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Applying geochemical signatures of atmospheric dust to distinguish current mine emissions from legacy sources
Accepted Manuscript Applying geochemical signatures of atmospheric dust to distinguish current mine emissions from legacy sources Chenyin Dong, Mark Patrick Taylor PII:
S1352-2310(17)30262-5
DOI:
10.1016/j.atmosenv.2017.04.024
Reference:
AEA 15291
To appear in:
Atmospheric Environment
Received Date: 5 January 2017 Revised Date:
12 April 2017
Accepted Date: 14 April 2017
Please cite this article as: Dong, C., Taylor, M.P., Applying geochemical signatures of atmospheric dust to distinguish current mine emissions from legacy sources, Atmospheric Environment (2017), doi: 10.1016/j.atmosenv.2017.04.024. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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GRAPHICAL ABSTRACT
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Perilya Broken Hill mining operation: recently mined and crushed lead and zinc ore stored outside in an uncontained manner.
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Applying geochemical signatures of atmospheric
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dust to distinguish current mine emissions from
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legacy sources
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Chenyin Donga*, Mark Patrick Taylora,b
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Department of Environmental Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
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Energy and Environmental Contaminants Research Centre, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
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* Corresponding Author
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Phone: +61 9850 4221; email: [email protected]
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ABSTRACT
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Resolving the source of environmental contamination is the critical first step in remediation and
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exposure prevention. Australia’s oldest silver-zinc-lead mine at Broken Hill (>130 years old) has
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generated a legacy of contamination and is associated with persistent elevated childhood blood
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lead (Pb) levels. However, the source of environmental Pb remains in dispute: current mine
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emissions; remobilized mine-legacy lead in soils and dusts; and natural lead from geological
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weathering of the gossan ore body. Multiple lines of evidence used to resolve this conundrum
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include spatial and temporal variations in dust Pb concentrations and bioaccessibility, Pb isotopic
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compositions, particle morphology and mineralogy. Total dust Pb loading (mean 255 µg/m2/day)
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and its bioaccessibility (mean 75 % of total Pb) is greatest adjacent to the active mining
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operations. Unweathered galena (PbS) found in contemporary dust deposits contrast markedly to
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Pb-bearing particles from mine-tailings and weathered gossan samples. Contemporary dust
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particles were more angular, had higher sulfur content and had little or no iron and manganese.
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Dust adjacent to the mine has Pb isotopic compositions (208Pb/207Pb: 2.3197; 206Pb/207Pb: 1.0406)
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that closely match (99 %) the ore body with values slightly lower (95 %) at the edge of the city.
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The weight of evidence supports the conclusion that contemporary dust Pb contamination in
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Broken Hill is primarily sourced from current mining activities and not weathering or legacy
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sources.
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KEYWORDS
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Bioaccessibility, Pb isotopes, SEM/EDS, natural weathering, legacy emissions, Broken Hill
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1. INTRODUCTION
The minerals resource industry contributes 8.7 % to the Australian gross domestic product,
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placing the nation as one of world’s leading resource nations (Australian Bureau of Statistics,
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2000; Australian Government, 2015). Despite the benefits of resource extraction and use, its
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adverse impacts remain a significant ongoing global concern (Thornton, 1996; Tong et al., 2000;
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Ericson et al., 2016; Pure Earth and Green Cross, 2016). While the consequences of toxic metal
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exposure is well understood (Lanphear, 2015), the sources (Kristensen and Taylor 2016) and the
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subsequent health risks from ore processing and emissions on adjoining communities tend to be
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minimized by polluters and government agencies (e.g. Taylor and Schniering, 2010; Taylor et
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al., 2014a; 2015; Sullivan and Green 2016). Strategies include using questionable scientific
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claims and disputing contamination sources (Sullivan, 2014; Spear et al., 2015).
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Broken Hill, in far west New South Wales (NSW), contains the world’s largest silver-lead-zinc
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(Ag-Pb-Zn) mineral deposit (Solomon, 1988). The ore deposit was discovered in 1883 and has
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since been mined uninterrupted (Kristensen and Taylor, 2016). Smelting of ore was conducted
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from 1886 until 1898 until it was relocated to Port Pirie due to a lack of local fuel sources for
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smelting (Woodward, 1965; Solomon, 1988). The ore processing operations have left behind a
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legacy of widespread Pb contamination in the adjoining residential community, with
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occupational and community Pb poisoning being reported as early as 1893 (Thompson et al.,
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1893). Systematic investigation of childhood blood Pb levels commenced in 1991 at which time
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86 % of children had blood Pb levels ≥ 10 µg/dL (the upper acceptable blood Pb value until
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2015) (Lyle et al., 2006).
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A series of studies about sources and pathways of environmental Pb were conducted in the
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1990s (Woodward-Clyde, 1993; Gulson et al., 1994a,b; Boreland et al., 2002). A prevailing
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perspective at the time was that current mining operations were not a dominant source of
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contamination compared to other emissions (Woodward-Clyde Pty Ltd, 1993, p. 5-3).
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Nevertheless, stable Pb isotopic composition analysis indicated childhood blood Pb in Broken
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Hill was predominantly derived from the local ore body (Gulson et al., 1994a). Further, hand-to-
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mouth activity was subsequently shown to be an important exposure pathway for childhood lead
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exposure (Gulson et al., 1994b, 2004).
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In 1994, the NSW State Government undertook the remediation of homes of children with
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high blood Pb levels (> 15 µg/dL) (Lyle et al., 2006). Since this time there has been a overall
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reduction in children’s blood Pb concentrations (Lesjak et al., 2015). However, in recent years
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the proportion of children with a blood Pb level > 10 µg/dL increased from 12.6 % (2010) to 21
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% (2012) and remained at ~20 % after 2012 (Lesjak et al., 2015). In 2015, Australia’s National
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Health and Medical Research Council (NHMRC) lowered the blood Pb intervention
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concentration to 5 µg/dL, resulting in ~50 % of children under 5 years of age with a blood Pb
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concentration in excess of this new guideline (Taylor et al., 2014b; Lesjak et al., 2015).
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The recent increase in Broken Hill childhood blood Pb levels has stimulated further
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environmental contamination studies (Taylor et al., 2014c) and AUD$13 million from the NSW
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Government to ‘rejuvenate the Broken Hill Environment Lead Program to address the issue of
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blood Pb levels in local children’ (Humphries, 2015). However, targeted remediation on sources
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is challenging because the primary source of contemporary environment Pb in Broken Hill
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continues to remain in dispute — with arguments ranging from naturally occurring Pb, legacy
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contamination or contemporary emissions and depositions. For example, the misconception
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about the source of Broken Hill environmental lead exposure was re-circulated again in 2015 by
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Dr Rob Stokes, NSW Minister for Environment (at that time) (Humphries, 2015).
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Recent assessments of soils and contemporary dusts have revealed two critical facts: 1) surface
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soil and dust Pb loading are predominantly derived from the ore body and 2) surface soil and
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dust Pb loading is unlikely to be related to natural weathering and dispersal of the lead rich ore
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from the gossan ore body (Kristensen and Taylor, 2016; Taylor et al., 2014c). As noted more
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than two-decades ago by Gulson et al. (1994a,b) dust Pb is the primary pathway for childhood Pb
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exposures (cf. Lanphear et al., 1996, 2002; Mackay et al., 2013). Therefore, in order to undertake
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targeted and effective remediation to reduce childhood Pb levels, the precise sources and
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mechanisms of Pb contamination need to be resolved unequivocally. This study investigates
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sources of contemporary dust Pb deposition in Broken Hill using a multiple lines of evidence
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approach: spatial and temporal variations in dust Pb concentrations, its bioaccessability, Pb
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isotopic compositions, particle morphology and chemical compositions.
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2. STUDY AREA AND METHODS
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2.1 Study area Broken Hill has a hot, arid climate with a mean annual precipitation of 260 mm (Stern et al.,
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2000; Bureau of Metrology, 2016a). Prevailing winds are predominantly from the south to north
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(Bureau of Metrology, 2016b). Currently, two mining companies operate in the city of Broken
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Hill: CBH Rasp Mine and Perilya Limited (Figure 1). The reported atmospheric Pb emissions for
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CBH Rasp Mine and Perilya Limited in 2014 were 0.09 and 29 tonnes, respectively (NPI,
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2015a,b). Atmospheric lead emissions from Perilya’s operations during the period 2002–2014
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are estimated to be 137.4 tonnes (Supplementary Table S1). Since 2011, the atmospheric Pb
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emissions from Perilya Limited’s operations have averaged ~30 tonnes per year (Supplementary
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Table S1), ranking it as the 4th largest emitter of Pb in Australia (NPI, 2015c). Perilya Limited
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has two operations in Broken Hill – its northern and southern operations (Figure 1). The southern
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mining operations (hereafter referred to as mining operations) are currently the only active site,
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and emissions from this site form the focus of this investigation.
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INSERT FIGURE 1
2.2 Sample collection
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Dust Pb loading and its sources in the community were measured using six sampling sites
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distributed across the residential area of Broken Hill (Figure 1). Dust monitoring sites belonging
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to the Broken Hill mining companies are located predominantly on the mining leases or close to
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their operations and do not monitor dust deposition in the residential areas (CBH, 2016; Perilya
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Limited, 2016). Dust gauge monitoring for this study was undertaken in accordance with the
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relevant Australian standard (Standard Australia, 2003). Sampling consisted of placing a 150 mm
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diameter glass funnel placed into a 4 L glass bottle ~2 m off the ground and mounted on a tripod.
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Samples were collected from each monitoring site every month for a year (Nov 2014 to Nov
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2015) and were analysed for their metal content and Pb isotopic compositions at the National
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Measurement Institute (NMI), North Ryde, Sydney. Samples of remnant gossan (the source of
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the original ore) (n = 3) were collected to assess morphological characteristics and chemical
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composition of natural, ancient weathered Pb-bearing particles. In addition, three samples were
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collected from a local mine-tailings dump as previous assessments have claimed tailings dumps
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were contributing a considerable amount of Pb contamination to the Broken Hill environment
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(Woodward-Clyde Pty Ltd, 1993, p. ES-2).
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2.3 Samples preparation and methods
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Dust gauge bottles were rinsed out using 500 ml of Milli-Q water on to pre-weighed filters to
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capture particulates for analysis. After drying overnight at 105 °C followed by reweighing, the
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dry filters were digested using a two-step sequential extraction (NMI, 2014). Step 1: 20 ml of 0.1
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M HCl for 2 hours at room temperature (to test for bioaccessible Pb); centrifuged at 4000 rpm
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for 10 minutes with the supernatant decanted into another new centrifuge tube. Bioaccessibility
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is a laboratory proxy for bioavailability, which is determined via the use of laboratory animals.
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Step 2: The remaining solid residue was further digested using 3 ml of 16 M HNO3 and 3 ml of
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10 M HCl for 2 hours at 105°C. The supernatant from step 1 and 2 were analysed for
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bioaccessible and residual Pb concentrations, respectively. The total acid extractable Pb equals to
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the bioaccessible Pb (step 1) plus the residual Pb (step 2). Analysis for Pb concentration and its
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isotopic compositions were measured using an Agilent 7900 Inductively Coupled Plasma Mass
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Spectrometer (ICP-MS) at NMI. Both methods at NMI are NATA (National Association of
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Testing Authorities) accredited. Lead isotopic composition data quality on the PerkinElmer Elan
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DRC II has been established by Kristensen et al. (2016).
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The metal content of five blank filters was determined from the analysis of 500 ml of Milli-Q
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water that had been passed through each filter. The five blank filter samples returned < 0.03 and
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< 0.1 µg/filter for bioaccessible and residual Pb analysis, respectively. National Measurement
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Institute in-house reference materials AGAL-10 (Hawkesbury River Sediment, n = 3) and
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AGAL-12 (biosoil, n = 3) were processed with dust gauge samples. Relative standard deviations
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(RSDs) of AGAL-10 and AGAL-12 were 2.5 % and 2.8 % for bioaccessible Pb and 2.0 % and
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6.7 % for residual Pb analysis, respectively. Mean recovery rates of AGAL-10 and AGAL-12
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were 102 % and 107 % for total acid digestible Pb concentrations (step 1 + step 2). Mean
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recovery rates for sample matrix spikes were 99 % and 96 % for bioaccessible Pb (step 1) and
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the residual Pb analysis (step 2), respectively.
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Dust gauge samples were diluted to 10 µg/L for Pb isotopic composition analysis.
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Concentration matched NIST SRM 981 (natural Pb isotope composition standard) bracketed
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each sample to correct for mass fractionation. The relative standard deviation (RSD) was 0.8 %
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for
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uncertainty was 0.0005 for 204Pb/206Pb, 0.004 for 207Pb/206Pb and 0.009 for 208Pb/206Pb.
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Pb/206Pb, 0.42 % for
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Pb/206Pb and 0.40 % for
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Pb/206Pb, respectively. Analytical
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For particle morphology and chemical compositions, dust was analysed using a JEOL JSM-
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6480 scanning electron microscope (SEM) with an EX-94300 SDD energy dispersive X-ray
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analyser (EDS). Carbon coating was carried out using a Quorum Q150T sputter coater. Three
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fields were selected randomly to identify dust Pb particles at 110 times magnification. Lead
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minerals were readily identified as bright particles due to their high atomic number in the
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backscatter electron imaging mode (Harding, 2002). The EDS data was processed using the ZAF
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Method Standardless Quantitative Analysis (van Borm and Adams, 1991).
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3. RESULTS AND DISCUSSION
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3.1 Dust Pb loading and bioaccessibility
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The two sites closest to the mining operations (D1 and D2, Figure 2) had the highest dust Pb
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loading of all monitoring sites with mean values of 255 µg/m2/day and 248 µg/m2/day,
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respectively (Figure 2, Supplementary Table S2). Site D2, located north of the mining
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operations, had higher dust Pb loading in summer (mean 270 µg/m2/day) than winter (93
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µg/m2/day) (Supplementary Table S2). By contrast, site D1, located on the southern side of the
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mining operations had higher dust Pb loading in winter (mean 217 µg/m2/day) than summer (102
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µg/m2/day) (Supplementary Table S2). During summer, the dominant wind direction in Broken
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Hill is northwards, while during winter the wind direction is reversed (Bureau of Metrology,
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2016c,d). The other four dust monitoring sites located to the north of mining operations
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displayed similar seasonal Pb dust loading patterns to those recorded at site D2 (Supplementary
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Table S2). These prevailing wind patterns are reflected in the dust Pb loadings and their relative
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position to the mining operations.
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There are no Australian guidelines for dust Pb deposition. However, the Queensland state
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government has set dust Pb at 100 µg/m2/day as a trigger for environmental monitoring of Mount
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Isa Mines (Taylor et al., 2014a). This is the same value as listed in the German TA Luft (TA Luft,
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2002), which has been used elsewhere as a benchmark value for assessing Pb deposition (Taylor
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et al., 2015). Further, the World Health Organization indicated that Pb dust deposition > 250
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µg/m2/day will increase blood lead levels (WHO, 2000). Using this guideline as a benchmark,
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mean dust Pb loadings at site D1 (255 µg/m2/day) and D2 (248 µg/m2/day) exceed and approach
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acceptable international values (Figure 2). Dust Pb loading generally decreased with distance
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away from the southern operations (Figure 2).
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The mean dust Pb bioaccessibility was 68 % (range 23–92 %) (Supplementary Table S3),
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which is consistent with a previous study of Broken Hill household vacuum dust (Gulson et al.,
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1994a). Total Pb loading correlated strongly with bioaccessible Pb concentrations (r2 = 0.95,
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p<0.01) (Figure 3). Bioaccessible Pb concentration exceeded the Queensland dust Pb loading
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guideline of 100 µg/m2/day at sites D1 (mean 181 µg/m2/day) and D2 (mean 178 µg/m2/day)
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with bioaccessibility decreasing with distance away from the mining operations (Figure 2,
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Supplementary Table S3). Least significant difference (LSD) analysis (Supplementary Table S4)
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revealed the mean bioaccessibility values at the two closest sites (D1 and D2) were significantly
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(p<0.05) greater compared to the furthest site, D6. Bioaccessibility at sites located at an
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‘intermediate’ distance (D3, D4 and D5) from the mining operations, were not statistically
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different to sites closest or furthest away from the mining operations. As demonstrated by the
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spatial distribution of total dust Pb, dust bioaccessibility data suggests that children living closest
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to the mining operations are at greater risk of Pb exposure. Moreover, Yang and Cattle (2015)
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showed that soil Pb bioaccessibility generally decreased with distance from the ore body, which
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concurs with the data presented here.
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In order to quantify the contribution of ore body Pb to dust Pb, the Pb isotopic composition mixing model devised by Larsen et al. (2012) was applied to the data: =
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3.2 Dust Pb isotopic compositions
where
[( [(
/ /
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is the percent contribution of ore body Pb in the analysed samples; (206Pb/207Pb)s and
(208Pb/207Pb)s are the isotopic compositions of Pb in sample; (206Pb/207Pb)o and (208Pb/207Pb)o are
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the Pb isotopic compositions of ore body; and (206Pb/207Pb)b and (208Pb/207Pb)b are from Broken
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Hill background soil (Kristensen and Taylor, 2016). Contemporary dust deposits have a Pb
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isotopic composition similar to the composition of the Broken Hill ore body (Figure 4). Dust
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samples from the proximal site D1, contain ~ 99 % Broken Hill ore, while distal dust samples
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(D6) contain a slightly lower proportion (~ 94 %) of Broken Hill ore, suggesting mixing with
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other sources of Pb. Mixing model analysis reveals seasonal differences in dust Pb isotopic
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compositions. In spring and summer, dust samples have a greater proportion of Pb derived from
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Broken Hill ore (~ 97 %) than in winter (~ 94 %). The data also corresponds to the dominant
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seasonal winds: southerlies in spring and summer (i.e. from the direction of the mining
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operations) and northerlies in winter, (towards the mining operations).
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INSERT FIGURE 4
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3.3 Morphology and geochemical compositions of Pb particles Dust Pb particle surface morphology and mineral composition was assessed in dust gauge,
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gossan and tailings dump samples for comparison. Analysis of SEM images and EDS of Pb
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bearing particles showed that they could be categories into four groups (Figure 5):
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i) Angular and well-crystallized galena (PbS) particles with no apparent chemical and
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physical surface alteration, which also contain high sulfur (S) concentrations and minor
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Fe, Mn, K, Mg, Ca, Al, Na, Cu and Zn concentrations.
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concentrations.
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ii) Subrounded galena (PbS) particles with minor Fe, Mn, K, Mg, Ca, Al, Na, Cu, Zn
iii) Pb bearing particles with cavities, with minor Fe, P, Cl, Ca, Al, Na, Cu concentrations and no elemental S detected.
iv) Rounded and sub-rounded Pb bearing particles with major weathering effects and high concentrations of Mn and Fe.
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Dust Pb particle deposits are dominated by those from groups (i) and (ii), while tailings dump
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particles and weathered gossan particles are from groups (iii) and (iv), respectively. Moreover,
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angular and well-crystallized galena particles were more commonly observed from dust collected
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at site D1, closest to the mining operation. The size of galena particles from site D1 ranges from
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20-50 µm, while galena particles from more distal sites are finer, at ~ 5 µm. Lead particles from
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tailings dump were classified as group (iii), while those from the gossan exhibited, as expected,
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extensive weathering and were classified as group (iv). Particle chemical composition analysis
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using EDS showed that no S was detected in tailings dump particles. Weathered gossan particles
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were characterized as having relatively abundant Fe and Mn compared with contemporary dust
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particles (Supplementary Table S5).
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INSERT FIGURE 5
255 3.4 Sources of dust Pb particles
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A study by Gulson et al. (1994a) found leaded gasoline to be a significant contributor to Pb in air
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in Broken Hill during 1991/1992. Since then, Pb in gasoline has been banned in Australia in
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2002. Contemporary dust Pb isotopic compositions reveals a clear shift away from leaded
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gasoline sources, with Pb isotopic compositions similar to the Broken Hill ore body (Figure 4).
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Moreover, Kristensen and Taylor (2016) found that other Pb sources including leaded paint and
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old batteries cannot reasonably account for the widespread Pb contamination across Broken Hill.
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However, stable Pb isotopic compositions on their own do not demonstrate unequivocally
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whether contemporary dust Pb depositions are derived from remobilised legacy emissions or
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whether they are from current emissions, natural sources or other anthropogenic activities. The
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addition of dust particle morphology combined with chemical compositions can reveal
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weathering processes of Pb particles, assisting in interpreting sources of origin (Kristensen et al.,
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2015; Ettler et al., 2016).
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Lead emissions from the former 28 Broken Hill Pb smelters operating between 1886−1897
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(Woodward, 1965) were significant with an estimated emission rate of approximately 110 tonnes
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of Pb per week in 1893 (Thompson et al., 1893). By comparison, the total atmospheric Pb
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emissions from mining operations between 1998−2015 were 140 tonnes (NPI, 2015c). Although
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smelter emissions and depositions have significantly contributed to environmental Pb in Broken
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Hill, it remains unclear what contribution they have to contemporary dust Pb depositions around
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the city. Characteristic spherical metal(loid)-bearing particles are emitted from Pb and Zn
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smelters, steelworks and power stations (Tye et al., 2006; Csavina et al., 2014). Such particles
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are easily distinguished from geogenic grains due to their characteristic morphology (Csavina et
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al., 2011; 2014). Spherical Fe oxide particles have been widely reported from historical and
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active smelting communities in the world (Tye et al., 2006; Csavina et al., 2014; Ettler et al.,
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2016). In Mount Isa, an Australian smelting community, these spherical Fe oxides contain
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approximately 11 % Pb (Csavina et al., 2014). However, no spherical particles were observed in
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Broken Hill dust, suggesting that legacy Pb from smelting operations are not contributing to
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contemporary dust Pb exposures.
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Other sources of environmental Pb include unconsolidated tailing deposits, which were subject
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to redistribution around the city prior to major remediation efforts in the 1990s (Supplementary
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Figure S6). Since the 1890s, unweathered sulphide-rich Pb and Zn ore has been mined and
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concentrated in Broken Hill (Blainey, 1968). Ore processing and concentrating using the froth
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flotation technique separates the valuable sulphide minerals from gangue (waste) minerals
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(Lynch, 1992). As a result, particles sourced from tailing dumps are likely to lack S compared to
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the ore body, providing an added opportunity for geochemical discrimination of contamination
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sources.
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Samples collected from the gossan were rounded/subrounded with high concentrations of Fe
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and Mn, suggesting these Pb particles have undergone significant long-term weathering. Fresh
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galena crystal particles were present in all of the dust gauge samples, and decreased in particle
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size with distance from the mining operations. Given the softness of the mineral galena (Mohs
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hardness 2.5), it is anticipated that atmospheric exposure is likely to induce chemical and
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physical alterations producing weathered surfaces and particle rounding (Kristensen et al., 2015;
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Davis et al., 2016). Under these assumptions, cuboid and sub-rounded galena particles in
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contemporary dust particles suggest these depositions are derived from new sources and have
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experienced limited transport in the environment. The marked morphological and chemical
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differences in dust gauge (contemporary) samples versus those sampled from gossan/tailing
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dumps supports the contention that Pb-rich dusts are sourced from current mining operations and
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not from legacy depositions that have been recycled. Galena is a dense mineral (7.57 g/cm3) and
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subsequently the atmospheric transport of larger particles is likely to be limited. For example,
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using the method detailed by Hinds (1999), cubic galena particles > 16 µm would travel < 1 km
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when exposed to the city’s average wind speed of 3.5 m/s (9 am) (Bureau of Metrology, 2016a).
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The diminishing size of galena particles with distance away from the active mining operations
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supports the contention that current mining operations are the primary source of contemporary
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Pb depositions. The video clip (Video 1) shows the transport of dusts from the lead and zinc ore
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pile at the head of the Perilya Mine at Broken Hill, NSW.
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4. STUDY LIMITATIONS
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The assessment of particles using SEM was a semi-quantitative technique. Further analysis of
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dust depositions using a quantitative SEM system would enable quantification of the relative
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portions of different grain morphologies and compositions (Williamson et al., 2013; Morrison et
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al., 2016). Dust sampling was uni-directional and additional relevant information could be
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complied by adding directional dust deposition sampling. In addition, the application of Micro-
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Orifice Uniform Deposit Impactor (MOUDI) would allow size partitioning coupled with
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geochemical and SEM analysis of different aerosol fractions (e.g. Miranda et al., 2002; Csavina
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2011; 2014; Félix et al., 2015).
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5. CONCLUSION
This assessment of contemporary dust deposits reveals the following relevant facts that are likely to be influential in determining blood Pb exposures in Broken Hill children: •
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Dust Pb bioaccessibility ranges between 23–92 % up to a mean of 68 %. This demonstrates the Broken Hill community, particularly those living close to the mining
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operations, are at risk of Pb exposure from contemporary dust depositions.
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•
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Lead isotopic composition analysis indicates that contemporary Pb dust is sourced mainly from the Broken Hill ore body. Former sources including leaded gasoline emissions are
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no longer significant.
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Dust particle morphology and chemical composition corresponds to characteristics associated with current physical mining activities (e.g. crushing, grinding and loading).
The application of multiple lines of geochemical evidence demonstrates that it is possible to
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establish the relative importance of contemporary emissions and depositions against legacy
340
sources. While it may seem ‘obvious’ to an outside observer that contamination in mining towns
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are derived from the most likely source, a weight of evidence is required to shift the status quo
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and stimulate, targeted remediation and abatement. Indeed, the NSW EPA have recently
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implemented a pollution reduction program for Perilya’s southern mining operations which
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include reducing waste pollution sources to soils and waters and developing a waste management
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plan for the entire mine site (NSW EPA, 2016). Assuming the changes to the mining operations
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are effective at markedly reducing Pb emissions, this may enable an opportunity for a ‘natural
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experiment’ of the subsequent changes in aerosol and dust Pb along with blood Pb outcomes.
348 ASSOCIATED CONTENT
350
Supporting Information
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Supplementary tables and figures (PDF) are available free of charge.
352
AUTHOR INFORMATION
353
Author Contributions
354
The research for this study completed by both authors. Both authors have approved the final
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version of the manuscript.
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Funding Sources
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C. Dong is funded via a International Macquarie University Research Excellence Scholarship
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(iMQRES No. 2014098) and received technical and practical support from the Broken Hill
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Environmental Lead Program (BHELP) as part of a Macquarie University–BHELP collaboration
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agreement. C. Dong also received laboratory and analytical support from the National
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Measurement Institute as part of a Macquarie University–National Measurement Institute PhD
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research collaboration agreement.
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Notes
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The authors declare no competing financial interest. M.P. Taylor is completing an independent
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‘Review of the New South Wales Environment Protection Authority’s Management of
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Contaminated Sites’ for the NSW Minister for the Environment and is also an advisor to the
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Broken Hill Environmental Lead Program. Chenyin Dong has no potential conflicts of interest to
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declare.
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369 ACKNOWLEDGMENTS
Dr. Janae Casvina is thanked for providing methods to evaluate travel distance of galena
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particles in Broken Hill. The authors are also grateful to Peter Oldsen and Frances Boreland
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(NSW EPA, Broken Hill Environmental Lead Program), Shiva Prasad, Andrew Evans, Michael
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Wu, Ping Di (National Measurement Institute), Nicole Vella, Nadia Suarez-Bosche and Sue
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Lindsay (Macquarie University Microscopy Unit) for sample collection and analysis. Mr Marek
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Rouillon and Dr Guan Wang are thanked for reviewing early drafts of the manuscript.
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REFERENCES Australian Bureau of Statistics, 2000. The Australian Mining Industry: From Settlement to 2000.
380
http://www.abs.gov.au/ausstats/abs%40.nsf/94713ad445ff1425ca25682000192af2/93136e734ff6
381
2aa2ca2569de00271b10!OpenDocument (accessed 01.11.16)
RI PT
379
Australian Government, 2015. Australian Industry Report – 2015. Office of the Chief
383
Economist, Department of Industry, Innovation and Science. http://www.industry.gov.au/Office-
384
of-the-Chief-Economist/Publications/Documents/AIR2015.pdf (accessed 13.09.16)
385
Blainey, G., 1968. The Rise of Broken Hill. Macmillan of Australia, Melbourne.
386
Bureau
388
Metrology,
M AN U
of
2016a.
Climate
statistics
for
Broken
http://www.bom.gov.au/climate/averages/tables/cw_047007.shtml (accessed 24.07.16) Bureau of Metrology, 2016b. Wind speed and direction rose at Broken Hill. http://www.bom.gov.au/cgi-
390
bin/climate/cgi_bin_scripts/windrose_selector.cgi?period=Annual&type=9&location=47007
391
(accessed 24.07.16)
EP
389
Bureau of Metrology, 2016c. Summer−Wind speed and direction rose at Broken Hill.
AC C
392
Hill.
TE D
387
SC
382
393
http://www.bom.gov.au/cgi-
394
bin/climate/cgi_bin_scripts/windrose_selector.cgi?period=Summer&type=9&location=47007&S
395
ubmit=Get+Rose (accessed 24.07.16)
396 397
Bureau of Metrology, 2016d. Winter−Wind speed and direction rose at Broken Hill. http://www.bom.gov.au/cgi-
19
ACCEPTED MANUSCRIPT
398
bin/climate/cgi_bin_scripts/windrose_selector.cgi?period=Winter&type=9&location=47007&Su
399
bmit=Get+Rose (accessed 24.07.16) Boreland, F., Lyle, D. M., Wlodarczyk, J., Balding, W. A., Reddan, S., 2002. Lead dust in
401
broken hill homes--a potential hazard for young children? Aust. N. Z. J. Public Health 26, 203-
402
207. CBH
Resources
Limited,
2016.
Environment
Monitoring
Overview.
SC
403
RI PT
400
http://www.cbhresources.com.au/files/6713/4551/1116/Monitoring_Overview_and_Criteria.pdf
405
(accessed 19.08.2016)
406 407
M AN U
404
Cooper, J. A., Reynolds, P. H., Richards, J. R., 1969. Double-spike calibration of the broken hill standard lead. Earth Planet. Sci. Lett. 6, 467-478.
Csavina, J., Landázuri A., Wonaschütz, A., Rine, K., Rheinheimer, P., Barbaris, B., Conant,
409
W., Sáez, A. E., Betterton, E. A., 2011. Metal and Metalloid Contaminants in Atmospheric
410
Aerosols from Mining Operations. Water Air Soil Pollut. 221, 145-157.
TE D
408
Csavina, J., Taylor, M. P., Félix, O., Rine, K. P., Sáez, A. E., Betterton, E. A., 2014. Size-
412
resolved dust and aerosol contaminants associated with copper and lead smelting emissions:
413
Implications for emission management and human health. Sci. Total Environ. 493, 750-756.
AC C
EP
411
414
Davis, J. J., Morrison, A. L., Gulson, B. L., 2016. Uncovering pathways of metal
415
contamination with microscopic techniques and lead isotopic tracing. Aust. J. Earth Sci. 63, 795-
416
803.
20
ACCEPTED MANUSCRIPT
Ericson, B., Caravanos, J., Keith, J., Taylor, M. P., Frostad, J., Fuller, R., Landrigan, P., 2016.
418
The Global Burden of Lead Toxicity Attributable to Informal Used Lead-Acid Battery (ULAB)
419
Sites. Ann. Glob. Health, accepted, DOI 10.1016/j.aogh.2016.10.009
RI PT
417
Ettler, V., Johan, Z., Kříbek, B., Veselovský, F., Mihaljevič, M., Vaněk, A., Penížek, V., Majer,
421
V., Sracek, O., Mapani, B., Kamona, F., Nyambe, I., 2016. Composition and fate of mine- and
422
smelter-derived particles in soils of humid subtropical and hot semi-arid areas. Sci. Total
423
Environ. 563–564, 329-339.
SC
420
Félix, O. I., Csavina, J., Field, J., Rine, K. P., Sáez, A. E., Betterton, E. A., 2015. Use of lead
425
isotopes to identify sources of metal and metalloid contaminants in atmospheric aerosol from
426
mining operations. Chemosphere 122, 219-226.
429 430
Metall. Proc. 19, 215-219.
TE D
428
Harding, D. P., 2002. Minearal identification using a scanning electron microscope. Miner.
Hinds, W. C., 1999. Aerosol Technology: Properties, Behavior, and Measurment of Airborne Particles, 2nd Eidtion. Wiely, New York.
EP
427
M AN U
424
Humphries, K. 2015. NSW Government commits more than $13 million to reduce lead levels
432
at Broken Hill. Media release: Kevin Humphries MP Minister for Natural Resources, Lands and
433
Water
434
2015. http://www.epa.nsw.gov.au/resources/MinMedia/EPAMin150213.pdf
435
05.01.2017).
436
AC C
431
Minister
for
Western
NSW,
13th
February (accessed
Gulson, B. L., 1986. Lead isotopes in mineral exploration. Elsevier: Amsterdam.
21
ACCEPTED MANUSCRIPT
Gulson, B. L., Mizon, K. J., Law, A. J., Korsch, M, J., Davis, J. J., 1994a. Source and
438
Pathways of Lead in Humans from the Broken Hill Mining Community – An Alternative Use of
439
Exploration Methods. Econ. Geol. 89, 889 – 908.
RI PT
437
Gulson, B. L., Davis, J. J., Mizon, K. J., Korsch, M. J., Law, A. J., Howarth, D., 1994b. Lead
441
Bioavailability in the Environment of Children: Blood Lead Levels in Children Can Be Elevated
442
in a Mining Community. Arch. Environ. Health 49, 326-331.
SC
440
Gulson, B. L., Mizon, K. J., Davis, J. J., Palmer, J. M., Vimpani, G., 2004. Indentification of
444
sources of lead in children in a primary zinc-lead smelter environment. Environ. Health Perspect.
445
112, 52 – 60.
M AN U
443
Kristensen, L. J., Taylor, M. P., Morrison, A. L., 2015. Lead and zinc dust depositions from
447
ore trains characterised using lead isotopic compositions. Environ. Sci. Process. Impacts 17, 631-
448
637.
TE D
446
Kristensen, L. J., Taylor, M. P., 2016. Unravelling a ‘miner’s myth’ that environmental
450
contamination in mining towns is naturally occurring. Environ. Geochem. Health 38, 1015-1027.
451
Kristensen, L. J., Taylor, M. P., Evans, A. J., 2016. Reply to Gulson’s comments on ‘Tracing
452
changes in atmospheric sources of lead contamination using lead isotopic compositions in
453
Australian red wine’. Chemosphere 154, 40-47.
455 456 457
AC C
454
EP
449
Lanphear, B. P., 2015. The Impact of Toxins on the Developing Brain. Annu. Rev. Publi. Health 36, 211-230. Lanphear, B. P., Hornung, R., Ho, M., Howard, C. R., Eberly, S., Knauf, K., 2002. Environmental lead exposure during early childhood. J. Pediatr. 140, 40-47.
22
ACCEPTED MANUSCRIPT
Lanphear, B. P., Weitzman, M., Winter, N. L., Eberly, S., Yakir, B., Emond, M., Matte, T. D.,
459
1996. Lead-contaminated house dust and urban children’s blood lead levels. Am. J. Public
460
Health 86, 1416-1421.
461 462
RI PT
458
Larsen, M. M., Blusztajn, J. S., Andersen, O., Dahllöf, I., 2012. Lead isotopes in marine surface sediments reveal historical use of leaded fuel. J. Environ. Monitor. 14, 2893-2901.
Lesjak, M., Jones, T., 2015. Lead Health Report 2014 - Children less than 5 years old in
464
Broken Hill. Population Health Unit, NSW Government, Western NSW & Far West Local
465
Health
466
http://www.fwlhd.health.nsw.gov.au/UserFiles/files/Directorates/Population%20Health/2014%2
467
0Lead%20Report.pdf (accessed 13.09.16).
District.
M AN U
SC
463
Lyle, D. M., Philips, A. R., Balding, W. A., Burke, H., Stokes, D., Corbett, S., Hall, J., 2006.
469
Dealing with lead in Broken Hill–Trends in blood lead levels in young children 1991–2003. Sci.
470
Total Environ. 359, 111-119.
472
Lynch, A. J., 1992. Broken Hill Metallurgy – A Story of Innovations in Processces, Equipment and Instruments. The AusIMM Annual Conference, Broken Hill.
EP
471
TE D
468
Mackay, A. K., Taylor, M. P., Munksgaard, N. C., Hudson-Edwards, K. A., Burn-Nunes, L.,
474
2013. Identification of environmental lead sources and pathways in mining and smelting town:
475
Mount Isa, Australia. Environ. Pollut. 180, 304-311.
476 477
AC C
473
Miranda, R. M., Andrade, M. F., Worobiec, A., Grieken, R. V., 2002. Characterisation of aerosol particles in the Sao Paulo Metropolitan Area. Atmos. Environ. 36, 345-352.
23
ACCEPTED MANUSCRIPT
Morrison, A. L., Swierczek, Z., Gulson, B. L., 2016. Visulisation and quantification of heavy
479
metal accessibility in smelter slags: The influence of morphology on availability. Environ. Pollut.
480
210, 271-281.
RI PT
478
National Measurement Institute (NMI), 2014. National Measurement Institute, Inorganic
482
Section, Method NT2.49: Determination of Acid Extractable Elements in Soils, Sediments,
483
Sludges and Solid Waste. Sdyney.
SC
481
National Pollutant Inventory (NPI), 2015a. 2014/2015 report for BROKEN HILL
485
OPERATION PTY LTD, CBH Resources – Rasp Mine – Broken Hill, NSW.
486
http://www.npi.gov.au/npidata/action/load/emission-by-individual-facility-
487
result/criteria/state/NSW/year/2015/jurisdiction-facility/1333 (accessed 19.08.16).
488
M AN U
484
National Pollutant Inventory (NPI), 2015b. 2014/2015 report for PERILYA BROKEN HILL LIMITED,
490
http://www.npi.gov.au/npidata/action/load/emission-by-individual-facility-
491
result/criteria/state/NSW/year/2015/jurisdiction-facility/125 (accessed 19.08.16).
494
National
Pollutant
Inventory
EP
493
Broken
Hill
Operations
(NPI),
2015c.
Hill,
NSW.
NPI
data
within
Broken
Hill.
New South Wales (NSW) EPA, 2016. Licence Variation of Environment Protection Licence No.
496
1&SYSUID=1&LICID=1545186 (accessed 02.11.16)
498
Broken
http://www.npi.gov.au/npidata/action/load/advance-search (accessed 23.07.16).
495
497
–
AC C
492
Perilya
TE D
489
Perilya
2688.
http://www.epa.nsw.gov.au/prpoeoapp/ViewPOEONotice.aspx?DOCID=-
Limited,
2016.
Monthly
reports:
environmental
reporting.
http://www.perilya.com.au/health--safety--environment/environment/reports (accessed 24.07.16).
24
ACCEPTED MANUSCRIPT
Pure Earth and Green Cross, 2016. The World’s Worst Pollution Problems 2016: The Toxics Beneath
501
01.11.16).
503 504 505 506
Feet.
http://worstpolluted.org/docs/WorldsWorst2016Spreads.pdf
Solomon, R. J., 1988. The richest lode: Broken Hill 1883-1988. Hale & Iremonger, Sydney, NSW.
Spear, M., Thomas, R., Sharader-Frechette, K., 2015. Commentary: Flawed Science Delays Smelter Cleanup and Worsens Health. Account. Res. 22, 41-60.
Standards Australia, 2003. Australian/New Zealand 3580.10.1:2003. Determinationof −
508
http://infostore.saiglobal.com/store/details.aspx?ProductID.373364.
Method.
Stern, H., de Hoedt, G., Ernst, J., 2000. Objective classification of Australian climates. Australian Bureau of Meteorology, Melbourne.
TE D
512
Gravimetric
Sullivan, M., 2014. Tainted Earth: Smelters, Public Health and the Environment. New Brunswick (US): Rutgers University Press.
EP
511
Matter
−
Particulate
510
Matter
Deposited
507
509
(accessed
SC
502
Our
RI PT
500
M AN U
499
Sullivan, M., Green, D., 2016. Misled about lead: an assessment of online public health
514
education material from Australia’s lead mining and smelting towns. Environ. Health 15:1. doi:
515
10.1186/s12940-015-0085-9.
516
AC C
513
TA Luft, 2002. Technical Instructions on Air Quality Control. In: First General Administration
517
Regulation
Pertaining
the
Federal
Immission
Control
518
http://www.bmub.bund.de/fileadmin/bmu-
519
import/files/pdfs/allgemein/application/pdf/taluft_engl.pdf (accessed 10.03.15).
Act.
25
ACCEPTED MANUSCRIPT
Taylor, M. P., Schniering, C., 2010. The public minimization of the risks associated with
521
environmental lead exposure and elevated blood lead levels in children, Mount Isa, Queensland,
522
Australia. Arch. Environ. Occup. Health 65, 45-48.
RI PT
520
Taylor, M. P., Davies, P. J., Kristensen, L. J., Csavina, J. L., 2014a. Licenced to pollute but not
524
to poison: The ineffectiveness of regulatory authorities at protecting public health from
525
atmospheric arsenic, lead and other contaminants resulting from mining and smelting operations.
526
Aeolian Res. 14, 35-52.
SC
523
Taylor, M. P., Winder, C., Lanphear, B. P., 2014b. Australia's leading public health body
528
delays action on the revision of the public health goal for blood lead exposures. Environ. Int. 70,
529
113-117.
M AN U
527
Taylor, M. P., Mould, S. A., Kristensen, L. J., Rouillon, M., 2014c. Environmental arsenic,
531
cadmium and lead dust emissions from metal mine operations: Implications for environmental
532
management, monitoring and human health. Environ. Res. 135, 296-303.
534
Taylor, M. P., 2015. Atmospherically deposited trace metals from bulk mineral concentrate port operations. Sci. Total Environ. 515-516, 143-152.
EP
533
TE D
530
Thompson, A. J., Hamlet, W. M., Thomas, J., 1893. Report of Board Appointed to Inquire into
536
the Prevalence and Prevention of Lead Poisoning at the Broken Hill Silver-Lead Mines to the
537
Honorable the Minister for Mines and Agriculture. Legislativ Assembly, New South Wales.
538 539
AC C
535
Thornton, I., 1996. Impacts of mining on the environment; some local, regional and global issues. Appl. Geochem. 11, 355-361.
26
ACCEPTED MANUSCRIPT
540 541
Tong, S. L., Schirnding, Y. E. von., Prapamontol, T., 2000. Environmental lead exposure: a public health problem of gobal dimensions. Bull. World Health Organ. 78, 1068-1077. Townsend, T. A., Yu, Z., McGoldrick, P., A. Hutton, J., 1998. Precise lead isotope ratios in
543
Australian galena samples by high resolution inductively coupled plasma mass spectrometry. J.
544
Anal. At. Spectrom. 13, 809-813.
RI PT
542
Tye, A. M., Hodgkinson, E. S., Rawlins, B. G., 2006. Microscopic and chemical studies of
546
metal particulates in tree bark and attic dust: evidence for historical atmospheric smelter
547
emissions, Humberside, UK. J. Environ. Monit. 8, 904-912.
551 552 553 554 555 556
M AN U
Williamson, B. J., Rollinson, G., Pirrie, D., 2013. Automated Mineralogical Analysis of PM10: New Parameters for accessing PM Toxicity. Environ. Sci. Technol. 47, 5570-5577.
TE D
550
Electron Probe Microanalysis of Microscopical Particles. X-Ray Spectrom. 20, 51-62.
Woodward-Clyde Pty Limited, 1993. Evaluation of environmental lead at Broken Hill. Report to the Environment Protection Authority.
EP
549
van Borm, W. A., Adams, F. C., 1991. A Standarless ZAF Correction for Semi-quantitative
Woodward, O. H., 1965. A review of the Broken Hill Lead-Silver-Zinc Industry. West Publishing Coroporation Pty. Ltd, Sydney, NSW.
AC C
548
SC
545
World Health Organization (WHO), 2000. Air Quality Guidelines for Europe: Second Edition.
557
Regional
558
http://www.euro.who.int/__data/assets/pdf_file/0005/74732/E71922.pdf (accessed 02.11.16)
559 560
Office
for
Europe,
Copenhagen.
Yang, K., Cattle, S. R., 2015. Bioaccessibility of lead in urban soil of Broken Hill, Australia: A study based on in vitro digestion and the IEUBK model. Sci. Total Environ. 538, 922-933.
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List of figure captions
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Figure 1. Study area and sites for dust gauge, tailings dump and gossan samples.
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distance of each site away from the mining operations is also shown.
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Figure 3. Linear relationship between total dust Pb and bioaccessible Pb loading values.
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Figure 4. Lead isotopic compositions of dust in Broken Hill. (a) comparison of sites, (b)
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comparison between spring/summer and winter samples. The averaged lead isotopic composition
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data of ore body in Broken Hill is from Cooper et al. (1969), Gulson (1986) and Townsend et al.
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(1998). The leaded gasoline and 1991/1992 dust Pb isotopic data are from Gulson et al. (1994a).
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The background soil values are from Kristensen and Taylor (2016). Standard deviations of the Pb
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isotopic compositions are also shown.
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Figure 5. Scanning electron micrographs taken using back-scattered electron mode (BSE) of
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Broken Hill Pb bearing particles. Energy-dispersive X-ray spectroscopy (EDS) results of dust
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gauge samples, tailings and gossan samples are also shown. The concentrations of elements are
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given as relative weight percentage.
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Video 1. Video showing dusts blowing off the lead and zinc ore pile at the head of the Perilya
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Mine in Broken Hill, NSW, Australia (dated 1 March 2015).
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Multiple approaches applied to identify sources of atmospheric dust contamination Broken Hill Pb in dust is highly bioaccessible with a mean of 68 % Former sources of contamination e.g. leaded gasoline are no longer significant Current mining activities contribute Pb-rich dust to the urban environment
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• • • •
S1352-2310(17)30262-5
DOI:
10.1016/j.atmosenv.2017.04.024
Reference:
AEA 15291
To appear in:
Atmospheric Environment
Received Date: 5 January 2017 Revised Date:
12 April 2017
Accepted Date: 14 April 2017
Please cite this article as: Dong, C., Taylor, M.P., Applying geochemical signatures of atmospheric dust to distinguish current mine emissions from legacy sources, Atmospheric Environment (2017), doi: 10.1016/j.atmosenv.2017.04.024. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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GRAPHICAL ABSTRACT
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Perilya Broken Hill mining operation: recently mined and crushed lead and zinc ore stored outside in an uncontained manner.
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Applying geochemical signatures of atmospheric
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dust to distinguish current mine emissions from
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legacy sources
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Chenyin Donga*, Mark Patrick Taylora,b
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Department of Environmental Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
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Energy and Environmental Contaminants Research Centre, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
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Phone: +61 9850 4221; email: [email protected]
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ABSTRACT
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Resolving the source of environmental contamination is the critical first step in remediation and
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exposure prevention. Australia’s oldest silver-zinc-lead mine at Broken Hill (>130 years old) has
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generated a legacy of contamination and is associated with persistent elevated childhood blood
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lead (Pb) levels. However, the source of environmental Pb remains in dispute: current mine
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emissions; remobilized mine-legacy lead in soils and dusts; and natural lead from geological
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weathering of the gossan ore body. Multiple lines of evidence used to resolve this conundrum
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include spatial and temporal variations in dust Pb concentrations and bioaccessibility, Pb isotopic
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compositions, particle morphology and mineralogy. Total dust Pb loading (mean 255 µg/m2/day)
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and its bioaccessibility (mean 75 % of total Pb) is greatest adjacent to the active mining
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operations. Unweathered galena (PbS) found in contemporary dust deposits contrast markedly to
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Pb-bearing particles from mine-tailings and weathered gossan samples. Contemporary dust
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particles were more angular, had higher sulfur content and had little or no iron and manganese.
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Dust adjacent to the mine has Pb isotopic compositions (208Pb/207Pb: 2.3197; 206Pb/207Pb: 1.0406)
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that closely match (99 %) the ore body with values slightly lower (95 %) at the edge of the city.
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The weight of evidence supports the conclusion that contemporary dust Pb contamination in
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Broken Hill is primarily sourced from current mining activities and not weathering or legacy
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sources.
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KEYWORDS
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Bioaccessibility, Pb isotopes, SEM/EDS, natural weathering, legacy emissions, Broken Hill
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1. INTRODUCTION
The minerals resource industry contributes 8.7 % to the Australian gross domestic product,
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placing the nation as one of world’s leading resource nations (Australian Bureau of Statistics,
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2000; Australian Government, 2015). Despite the benefits of resource extraction and use, its
37
adverse impacts remain a significant ongoing global concern (Thornton, 1996; Tong et al., 2000;
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Ericson et al., 2016; Pure Earth and Green Cross, 2016). While the consequences of toxic metal
39
exposure is well understood (Lanphear, 2015), the sources (Kristensen and Taylor 2016) and the
40
subsequent health risks from ore processing and emissions on adjoining communities tend to be
41
minimized by polluters and government agencies (e.g. Taylor and Schniering, 2010; Taylor et
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al., 2014a; 2015; Sullivan and Green 2016). Strategies include using questionable scientific
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claims and disputing contamination sources (Sullivan, 2014; Spear et al., 2015).
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Broken Hill, in far west New South Wales (NSW), contains the world’s largest silver-lead-zinc
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(Ag-Pb-Zn) mineral deposit (Solomon, 1988). The ore deposit was discovered in 1883 and has
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since been mined uninterrupted (Kristensen and Taylor, 2016). Smelting of ore was conducted
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from 1886 until 1898 until it was relocated to Port Pirie due to a lack of local fuel sources for
49
smelting (Woodward, 1965; Solomon, 1988). The ore processing operations have left behind a
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legacy of widespread Pb contamination in the adjoining residential community, with
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occupational and community Pb poisoning being reported as early as 1893 (Thompson et al.,
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1893). Systematic investigation of childhood blood Pb levels commenced in 1991 at which time
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86 % of children had blood Pb levels ≥ 10 µg/dL (the upper acceptable blood Pb value until
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2015) (Lyle et al., 2006).
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A series of studies about sources and pathways of environmental Pb were conducted in the
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1990s (Woodward-Clyde, 1993; Gulson et al., 1994a,b; Boreland et al., 2002). A prevailing
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perspective at the time was that current mining operations were not a dominant source of
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contamination compared to other emissions (Woodward-Clyde Pty Ltd, 1993, p. 5-3).
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Nevertheless, stable Pb isotopic composition analysis indicated childhood blood Pb in Broken
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Hill was predominantly derived from the local ore body (Gulson et al., 1994a). Further, hand-to-
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mouth activity was subsequently shown to be an important exposure pathway for childhood lead
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exposure (Gulson et al., 1994b, 2004).
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In 1994, the NSW State Government undertook the remediation of homes of children with
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high blood Pb levels (> 15 µg/dL) (Lyle et al., 2006). Since this time there has been a overall
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reduction in children’s blood Pb concentrations (Lesjak et al., 2015). However, in recent years
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the proportion of children with a blood Pb level > 10 µg/dL increased from 12.6 % (2010) to 21
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% (2012) and remained at ~20 % after 2012 (Lesjak et al., 2015). In 2015, Australia’s National
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Health and Medical Research Council (NHMRC) lowered the blood Pb intervention
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concentration to 5 µg/dL, resulting in ~50 % of children under 5 years of age with a blood Pb
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concentration in excess of this new guideline (Taylor et al., 2014b; Lesjak et al., 2015).
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The recent increase in Broken Hill childhood blood Pb levels has stimulated further
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environmental contamination studies (Taylor et al., 2014c) and AUD$13 million from the NSW
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Government to ‘rejuvenate the Broken Hill Environment Lead Program to address the issue of
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blood Pb levels in local children’ (Humphries, 2015). However, targeted remediation on sources
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is challenging because the primary source of contemporary environment Pb in Broken Hill
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continues to remain in dispute — with arguments ranging from naturally occurring Pb, legacy
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contamination or contemporary emissions and depositions. For example, the misconception
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about the source of Broken Hill environmental lead exposure was re-circulated again in 2015 by
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Dr Rob Stokes, NSW Minister for Environment (at that time) (Humphries, 2015).
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Recent assessments of soils and contemporary dusts have revealed two critical facts: 1) surface
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soil and dust Pb loading are predominantly derived from the ore body and 2) surface soil and
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dust Pb loading is unlikely to be related to natural weathering and dispersal of the lead rich ore
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from the gossan ore body (Kristensen and Taylor, 2016; Taylor et al., 2014c). As noted more
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than two-decades ago by Gulson et al. (1994a,b) dust Pb is the primary pathway for childhood Pb
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exposures (cf. Lanphear et al., 1996, 2002; Mackay et al., 2013). Therefore, in order to undertake
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targeted and effective remediation to reduce childhood Pb levels, the precise sources and
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mechanisms of Pb contamination need to be resolved unequivocally. This study investigates
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sources of contemporary dust Pb deposition in Broken Hill using a multiple lines of evidence
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approach: spatial and temporal variations in dust Pb concentrations, its bioaccessability, Pb
94
isotopic compositions, particle morphology and chemical compositions.
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2. STUDY AREA AND METHODS
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2.1 Study area Broken Hill has a hot, arid climate with a mean annual precipitation of 260 mm (Stern et al.,
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2000; Bureau of Metrology, 2016a). Prevailing winds are predominantly from the south to north
99
(Bureau of Metrology, 2016b). Currently, two mining companies operate in the city of Broken
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Hill: CBH Rasp Mine and Perilya Limited (Figure 1). The reported atmospheric Pb emissions for
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CBH Rasp Mine and Perilya Limited in 2014 were 0.09 and 29 tonnes, respectively (NPI,
102
2015a,b). Atmospheric lead emissions from Perilya’s operations during the period 2002–2014
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are estimated to be 137.4 tonnes (Supplementary Table S1). Since 2011, the atmospheric Pb
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emissions from Perilya Limited’s operations have averaged ~30 tonnes per year (Supplementary
105
Table S1), ranking it as the 4th largest emitter of Pb in Australia (NPI, 2015c). Perilya Limited
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has two operations in Broken Hill – its northern and southern operations (Figure 1). The southern
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mining operations (hereafter referred to as mining operations) are currently the only active site,
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and emissions from this site form the focus of this investigation.
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2.2 Sample collection
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Dust Pb loading and its sources in the community were measured using six sampling sites
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distributed across the residential area of Broken Hill (Figure 1). Dust monitoring sites belonging
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to the Broken Hill mining companies are located predominantly on the mining leases or close to
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their operations and do not monitor dust deposition in the residential areas (CBH, 2016; Perilya
117
Limited, 2016). Dust gauge monitoring for this study was undertaken in accordance with the
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relevant Australian standard (Standard Australia, 2003). Sampling consisted of placing a 150 mm
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diameter glass funnel placed into a 4 L glass bottle ~2 m off the ground and mounted on a tripod.
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Samples were collected from each monitoring site every month for a year (Nov 2014 to Nov
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2015) and were analysed for their metal content and Pb isotopic compositions at the National
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Measurement Institute (NMI), North Ryde, Sydney. Samples of remnant gossan (the source of
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the original ore) (n = 3) were collected to assess morphological characteristics and chemical
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composition of natural, ancient weathered Pb-bearing particles. In addition, three samples were
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collected from a local mine-tailings dump as previous assessments have claimed tailings dumps
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were contributing a considerable amount of Pb contamination to the Broken Hill environment
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(Woodward-Clyde Pty Ltd, 1993, p. ES-2).
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2.3 Samples preparation and methods
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Dust gauge bottles were rinsed out using 500 ml of Milli-Q water on to pre-weighed filters to
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capture particulates for analysis. After drying overnight at 105 °C followed by reweighing, the
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dry filters were digested using a two-step sequential extraction (NMI, 2014). Step 1: 20 ml of 0.1
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M HCl for 2 hours at room temperature (to test for bioaccessible Pb); centrifuged at 4000 rpm
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for 10 minutes with the supernatant decanted into another new centrifuge tube. Bioaccessibility
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is a laboratory proxy for bioavailability, which is determined via the use of laboratory animals.
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Step 2: The remaining solid residue was further digested using 3 ml of 16 M HNO3 and 3 ml of
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10 M HCl for 2 hours at 105°C. The supernatant from step 1 and 2 were analysed for
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bioaccessible and residual Pb concentrations, respectively. The total acid extractable Pb equals to
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the bioaccessible Pb (step 1) plus the residual Pb (step 2). Analysis for Pb concentration and its
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isotopic compositions were measured using an Agilent 7900 Inductively Coupled Plasma Mass
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Spectrometer (ICP-MS) at NMI. Both methods at NMI are NATA (National Association of
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Testing Authorities) accredited. Lead isotopic composition data quality on the PerkinElmer Elan
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DRC II has been established by Kristensen et al. (2016).
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The metal content of five blank filters was determined from the analysis of 500 ml of Milli-Q
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water that had been passed through each filter. The five blank filter samples returned < 0.03 and
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< 0.1 µg/filter for bioaccessible and residual Pb analysis, respectively. National Measurement
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Institute in-house reference materials AGAL-10 (Hawkesbury River Sediment, n = 3) and
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AGAL-12 (biosoil, n = 3) were processed with dust gauge samples. Relative standard deviations
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(RSDs) of AGAL-10 and AGAL-12 were 2.5 % and 2.8 % for bioaccessible Pb and 2.0 % and
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6.7 % for residual Pb analysis, respectively. Mean recovery rates of AGAL-10 and AGAL-12
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were 102 % and 107 % for total acid digestible Pb concentrations (step 1 + step 2). Mean
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recovery rates for sample matrix spikes were 99 % and 96 % for bioaccessible Pb (step 1) and
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the residual Pb analysis (step 2), respectively.
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Dust gauge samples were diluted to 10 µg/L for Pb isotopic composition analysis.
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Concentration matched NIST SRM 981 (natural Pb isotope composition standard) bracketed
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each sample to correct for mass fractionation. The relative standard deviation (RSD) was 0.8 %
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for
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uncertainty was 0.0005 for 204Pb/206Pb, 0.004 for 207Pb/206Pb and 0.009 for 208Pb/206Pb.
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Pb/206Pb, 0.42 % for
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Pb/206Pb and 0.40 % for
208
Pb/206Pb, respectively. Analytical
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For particle morphology and chemical compositions, dust was analysed using a JEOL JSM-
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6480 scanning electron microscope (SEM) with an EX-94300 SDD energy dispersive X-ray
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analyser (EDS). Carbon coating was carried out using a Quorum Q150T sputter coater. Three
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fields were selected randomly to identify dust Pb particles at 110 times magnification. Lead
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minerals were readily identified as bright particles due to their high atomic number in the
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backscatter electron imaging mode (Harding, 2002). The EDS data was processed using the ZAF
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Method Standardless Quantitative Analysis (van Borm and Adams, 1991).
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3. RESULTS AND DISCUSSION
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3.1 Dust Pb loading and bioaccessibility
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The two sites closest to the mining operations (D1 and D2, Figure 2) had the highest dust Pb
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loading of all monitoring sites with mean values of 255 µg/m2/day and 248 µg/m2/day,
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respectively (Figure 2, Supplementary Table S2). Site D2, located north of the mining
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operations, had higher dust Pb loading in summer (mean 270 µg/m2/day) than winter (93
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µg/m2/day) (Supplementary Table S2). By contrast, site D1, located on the southern side of the
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mining operations had higher dust Pb loading in winter (mean 217 µg/m2/day) than summer (102
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µg/m2/day) (Supplementary Table S2). During summer, the dominant wind direction in Broken
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Hill is northwards, while during winter the wind direction is reversed (Bureau of Metrology,
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2016c,d). The other four dust monitoring sites located to the north of mining operations
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displayed similar seasonal Pb dust loading patterns to those recorded at site D2 (Supplementary
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Table S2). These prevailing wind patterns are reflected in the dust Pb loadings and their relative
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position to the mining operations.
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INSERT FIGURE 2
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There are no Australian guidelines for dust Pb deposition. However, the Queensland state
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government has set dust Pb at 100 µg/m2/day as a trigger for environmental monitoring of Mount
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Isa Mines (Taylor et al., 2014a). This is the same value as listed in the German TA Luft (TA Luft,
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2002), which has been used elsewhere as a benchmark value for assessing Pb deposition (Taylor
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et al., 2015). Further, the World Health Organization indicated that Pb dust deposition > 250
191
µg/m2/day will increase blood lead levels (WHO, 2000). Using this guideline as a benchmark,
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mean dust Pb loadings at site D1 (255 µg/m2/day) and D2 (248 µg/m2/day) exceed and approach
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acceptable international values (Figure 2). Dust Pb loading generally decreased with distance
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away from the southern operations (Figure 2).
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The mean dust Pb bioaccessibility was 68 % (range 23–92 %) (Supplementary Table S3),
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which is consistent with a previous study of Broken Hill household vacuum dust (Gulson et al.,
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1994a). Total Pb loading correlated strongly with bioaccessible Pb concentrations (r2 = 0.95,
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p<0.01) (Figure 3). Bioaccessible Pb concentration exceeded the Queensland dust Pb loading
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guideline of 100 µg/m2/day at sites D1 (mean 181 µg/m2/day) and D2 (mean 178 µg/m2/day)
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with bioaccessibility decreasing with distance away from the mining operations (Figure 2,
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Supplementary Table S3). Least significant difference (LSD) analysis (Supplementary Table S4)
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revealed the mean bioaccessibility values at the two closest sites (D1 and D2) were significantly
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(p<0.05) greater compared to the furthest site, D6. Bioaccessibility at sites located at an
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‘intermediate’ distance (D3, D4 and D5) from the mining operations, were not statistically
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different to sites closest or furthest away from the mining operations. As demonstrated by the
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spatial distribution of total dust Pb, dust bioaccessibility data suggests that children living closest
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to the mining operations are at greater risk of Pb exposure. Moreover, Yang and Cattle (2015)
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showed that soil Pb bioaccessibility generally decreased with distance from the ore body, which
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concurs with the data presented here.
211 INSERT FIGURE 3
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In order to quantify the contribution of ore body Pb to dust Pb, the Pb isotopic composition mixing model devised by Larsen et al. (2012) was applied to the data: =
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3.2 Dust Pb isotopic compositions
where
[( [(
/ /
) −( ) −(
/ /
) ] + [( ) ] + [(
/ /
) −( ) −(
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/ /
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is the percent contribution of ore body Pb in the analysed samples; (206Pb/207Pb)s and
(208Pb/207Pb)s are the isotopic compositions of Pb in sample; (206Pb/207Pb)o and (208Pb/207Pb)o are
219
the Pb isotopic compositions of ore body; and (206Pb/207Pb)b and (208Pb/207Pb)b are from Broken
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Hill background soil (Kristensen and Taylor, 2016). Contemporary dust deposits have a Pb
221
isotopic composition similar to the composition of the Broken Hill ore body (Figure 4). Dust
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samples from the proximal site D1, contain ~ 99 % Broken Hill ore, while distal dust samples
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(D6) contain a slightly lower proportion (~ 94 %) of Broken Hill ore, suggesting mixing with
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other sources of Pb. Mixing model analysis reveals seasonal differences in dust Pb isotopic
225
compositions. In spring and summer, dust samples have a greater proportion of Pb derived from
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Broken Hill ore (~ 97 %) than in winter (~ 94 %). The data also corresponds to the dominant
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seasonal winds: southerlies in spring and summer (i.e. from the direction of the mining
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operations) and northerlies in winter, (towards the mining operations).
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INSERT FIGURE 4
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3.3 Morphology and geochemical compositions of Pb particles Dust Pb particle surface morphology and mineral composition was assessed in dust gauge,
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gossan and tailings dump samples for comparison. Analysis of SEM images and EDS of Pb
234
bearing particles showed that they could be categories into four groups (Figure 5):
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i) Angular and well-crystallized galena (PbS) particles with no apparent chemical and
236
physical surface alteration, which also contain high sulfur (S) concentrations and minor
237
Fe, Mn, K, Mg, Ca, Al, Na, Cu and Zn concentrations.
240 241 242 243
concentrations.
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ii) Subrounded galena (PbS) particles with minor Fe, Mn, K, Mg, Ca, Al, Na, Cu, Zn
iii) Pb bearing particles with cavities, with minor Fe, P, Cl, Ca, Al, Na, Cu concentrations and no elemental S detected.
iv) Rounded and sub-rounded Pb bearing particles with major weathering effects and high concentrations of Mn and Fe.
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Dust Pb particle deposits are dominated by those from groups (i) and (ii), while tailings dump
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particles and weathered gossan particles are from groups (iii) and (iv), respectively. Moreover,
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angular and well-crystallized galena particles were more commonly observed from dust collected
247
at site D1, closest to the mining operation. The size of galena particles from site D1 ranges from
248
20-50 µm, while galena particles from more distal sites are finer, at ~ 5 µm. Lead particles from
249
tailings dump were classified as group (iii), while those from the gossan exhibited, as expected,
250
extensive weathering and were classified as group (iv). Particle chemical composition analysis
251
using EDS showed that no S was detected in tailings dump particles. Weathered gossan particles
252
were characterized as having relatively abundant Fe and Mn compared with contemporary dust
253
particles (Supplementary Table S5).
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INSERT FIGURE 5
255 3.4 Sources of dust Pb particles
257
A study by Gulson et al. (1994a) found leaded gasoline to be a significant contributor to Pb in air
258
in Broken Hill during 1991/1992. Since then, Pb in gasoline has been banned in Australia in
259
2002. Contemporary dust Pb isotopic compositions reveals a clear shift away from leaded
260
gasoline sources, with Pb isotopic compositions similar to the Broken Hill ore body (Figure 4).
261
Moreover, Kristensen and Taylor (2016) found that other Pb sources including leaded paint and
262
old batteries cannot reasonably account for the widespread Pb contamination across Broken Hill.
263
However, stable Pb isotopic compositions on their own do not demonstrate unequivocally
264
whether contemporary dust Pb depositions are derived from remobilised legacy emissions or
265
whether they are from current emissions, natural sources or other anthropogenic activities. The
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addition of dust particle morphology combined with chemical compositions can reveal
267
weathering processes of Pb particles, assisting in interpreting sources of origin (Kristensen et al.,
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2015; Ettler et al., 2016).
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Lead emissions from the former 28 Broken Hill Pb smelters operating between 1886−1897
271
(Woodward, 1965) were significant with an estimated emission rate of approximately 110 tonnes
272
of Pb per week in 1893 (Thompson et al., 1893). By comparison, the total atmospheric Pb
273
emissions from mining operations between 1998−2015 were 140 tonnes (NPI, 2015c). Although
274
smelter emissions and depositions have significantly contributed to environmental Pb in Broken
275
Hill, it remains unclear what contribution they have to contemporary dust Pb depositions around
276
the city. Characteristic spherical metal(loid)-bearing particles are emitted from Pb and Zn
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smelters, steelworks and power stations (Tye et al., 2006; Csavina et al., 2014). Such particles
278
are easily distinguished from geogenic grains due to their characteristic morphology (Csavina et
279
al., 2011; 2014). Spherical Fe oxide particles have been widely reported from historical and
280
active smelting communities in the world (Tye et al., 2006; Csavina et al., 2014; Ettler et al.,
281
2016). In Mount Isa, an Australian smelting community, these spherical Fe oxides contain
282
approximately 11 % Pb (Csavina et al., 2014). However, no spherical particles were observed in
283
Broken Hill dust, suggesting that legacy Pb from smelting operations are not contributing to
284
contemporary dust Pb exposures.
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Other sources of environmental Pb include unconsolidated tailing deposits, which were subject
287
to redistribution around the city prior to major remediation efforts in the 1990s (Supplementary
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Figure S6). Since the 1890s, unweathered sulphide-rich Pb and Zn ore has been mined and
289
concentrated in Broken Hill (Blainey, 1968). Ore processing and concentrating using the froth
290
flotation technique separates the valuable sulphide minerals from gangue (waste) minerals
291
(Lynch, 1992). As a result, particles sourced from tailing dumps are likely to lack S compared to
292
the ore body, providing an added opportunity for geochemical discrimination of contamination
293
sources.
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Samples collected from the gossan were rounded/subrounded with high concentrations of Fe
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and Mn, suggesting these Pb particles have undergone significant long-term weathering. Fresh
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galena crystal particles were present in all of the dust gauge samples, and decreased in particle
298
size with distance from the mining operations. Given the softness of the mineral galena (Mohs
299
hardness 2.5), it is anticipated that atmospheric exposure is likely to induce chemical and
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physical alterations producing weathered surfaces and particle rounding (Kristensen et al., 2015;
301
Davis et al., 2016). Under these assumptions, cuboid and sub-rounded galena particles in
302
contemporary dust particles suggest these depositions are derived from new sources and have
303
experienced limited transport in the environment. The marked morphological and chemical
304
differences in dust gauge (contemporary) samples versus those sampled from gossan/tailing
305
dumps supports the contention that Pb-rich dusts are sourced from current mining operations and
306
not from legacy depositions that have been recycled. Galena is a dense mineral (7.57 g/cm3) and
307
subsequently the atmospheric transport of larger particles is likely to be limited. For example,
308
using the method detailed by Hinds (1999), cubic galena particles > 16 µm would travel < 1 km
309
when exposed to the city’s average wind speed of 3.5 m/s (9 am) (Bureau of Metrology, 2016a).
310
The diminishing size of galena particles with distance away from the active mining operations
311
supports the contention that current mining operations are the primary source of contemporary
312
Pb depositions. The video clip (Video 1) shows the transport of dusts from the lead and zinc ore
313
pile at the head of the Perilya Mine at Broken Hill, NSW.
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4. STUDY LIMITATIONS
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The assessment of particles using SEM was a semi-quantitative technique. Further analysis of
319
dust depositions using a quantitative SEM system would enable quantification of the relative
320
portions of different grain morphologies and compositions (Williamson et al., 2013; Morrison et
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al., 2016). Dust sampling was uni-directional and additional relevant information could be
322
complied by adding directional dust deposition sampling. In addition, the application of Micro-
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Orifice Uniform Deposit Impactor (MOUDI) would allow size partitioning coupled with
324
geochemical and SEM analysis of different aerosol fractions (e.g. Miranda et al., 2002; Csavina
325
2011; 2014; Félix et al., 2015).
328 329 330
5. CONCLUSION
This assessment of contemporary dust deposits reveals the following relevant facts that are likely to be influential in determining blood Pb exposures in Broken Hill children: •
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Dust Pb bioaccessibility ranges between 23–92 % up to a mean of 68 %. This demonstrates the Broken Hill community, particularly those living close to the mining
332
operations, are at risk of Pb exposure from contemporary dust depositions.
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•
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Lead isotopic composition analysis indicates that contemporary Pb dust is sourced mainly from the Broken Hill ore body. Former sources including leaded gasoline emissions are
335
no longer significant.
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•
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Dust particle morphology and chemical composition corresponds to characteristics associated with current physical mining activities (e.g. crushing, grinding and loading).
The application of multiple lines of geochemical evidence demonstrates that it is possible to
339
establish the relative importance of contemporary emissions and depositions against legacy
340
sources. While it may seem ‘obvious’ to an outside observer that contamination in mining towns
341
are derived from the most likely source, a weight of evidence is required to shift the status quo
342
and stimulate, targeted remediation and abatement. Indeed, the NSW EPA have recently
343
implemented a pollution reduction program for Perilya’s southern mining operations which
344
include reducing waste pollution sources to soils and waters and developing a waste management
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plan for the entire mine site (NSW EPA, 2016). Assuming the changes to the mining operations
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are effective at markedly reducing Pb emissions, this may enable an opportunity for a ‘natural
347
experiment’ of the subsequent changes in aerosol and dust Pb along with blood Pb outcomes.
348 ASSOCIATED CONTENT
350
Supporting Information
351
Supplementary tables and figures (PDF) are available free of charge.
352
AUTHOR INFORMATION
353
Author Contributions
354
The research for this study completed by both authors. Both authors have approved the final
355
version of the manuscript.
356
Funding Sources
357
C. Dong is funded via a International Macquarie University Research Excellence Scholarship
358
(iMQRES No. 2014098) and received technical and practical support from the Broken Hill
359
Environmental Lead Program (BHELP) as part of a Macquarie University–BHELP collaboration
360
agreement. C. Dong also received laboratory and analytical support from the National
361
Measurement Institute as part of a Macquarie University–National Measurement Institute PhD
362
research collaboration agreement.
363
Notes
364
The authors declare no competing financial interest. M.P. Taylor is completing an independent
365
‘Review of the New South Wales Environment Protection Authority’s Management of
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Contaminated Sites’ for the NSW Minister for the Environment and is also an advisor to the
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Broken Hill Environmental Lead Program. Chenyin Dong has no potential conflicts of interest to
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declare.
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369 ACKNOWLEDGMENTS
Dr. Janae Casvina is thanked for providing methods to evaluate travel distance of galena
372
particles in Broken Hill. The authors are also grateful to Peter Oldsen and Frances Boreland
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(NSW EPA, Broken Hill Environmental Lead Program), Shiva Prasad, Andrew Evans, Michael
374
Wu, Ping Di (National Measurement Institute), Nicole Vella, Nadia Suarez-Bosche and Sue
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Lindsay (Macquarie University Microscopy Unit) for sample collection and analysis. Mr Marek
376
Rouillon and Dr Guan Wang are thanked for reviewing early drafts of the manuscript.
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REFERENCES Australian Bureau of Statistics, 2000. The Australian Mining Industry: From Settlement to 2000.
380
http://www.abs.gov.au/ausstats/abs%40.nsf/94713ad445ff1425ca25682000192af2/93136e734ff6
381
2aa2ca2569de00271b10!OpenDocument (accessed 01.11.16)
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Australian Government, 2015. Australian Industry Report – 2015. Office of the Chief
383
Economist, Department of Industry, Innovation and Science. http://www.industry.gov.au/Office-
384
of-the-Chief-Economist/Publications/Documents/AIR2015.pdf (accessed 13.09.16)
385
Blainey, G., 1968. The Rise of Broken Hill. Macmillan of Australia, Melbourne.
386
Bureau
388
Metrology,
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2016a.
Climate
statistics
for
Broken
http://www.bom.gov.au/climate/averages/tables/cw_047007.shtml (accessed 24.07.16) Bureau of Metrology, 2016b. Wind speed and direction rose at Broken Hill. http://www.bom.gov.au/cgi-
390
bin/climate/cgi_bin_scripts/windrose_selector.cgi?period=Annual&type=9&location=47007
391
(accessed 24.07.16)
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Bureau of Metrology, 2016c. Summer−Wind speed and direction rose at Broken Hill.
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Hill.
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387
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382
393
http://www.bom.gov.au/cgi-
394
bin/climate/cgi_bin_scripts/windrose_selector.cgi?period=Summer&type=9&location=47007&S
395
ubmit=Get+Rose (accessed 24.07.16)
396 397
Bureau of Metrology, 2016d. Winter−Wind speed and direction rose at Broken Hill. http://www.bom.gov.au/cgi-
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ACCEPTED MANUSCRIPT
398
bin/climate/cgi_bin_scripts/windrose_selector.cgi?period=Winter&type=9&location=47007&Su
399
bmit=Get+Rose (accessed 24.07.16) Boreland, F., Lyle, D. M., Wlodarczyk, J., Balding, W. A., Reddan, S., 2002. Lead dust in
401
broken hill homes--a potential hazard for young children? Aust. N. Z. J. Public Health 26, 203-
402
207. CBH
Resources
Limited,
2016.
Environment
Monitoring
Overview.
SC
403
RI PT
400
http://www.cbhresources.com.au/files/6713/4551/1116/Monitoring_Overview_and_Criteria.pdf
405
(accessed 19.08.2016)
406 407
M AN U
404
Cooper, J. A., Reynolds, P. H., Richards, J. R., 1969. Double-spike calibration of the broken hill standard lead. Earth Planet. Sci. Lett. 6, 467-478.
Csavina, J., Landázuri A., Wonaschütz, A., Rine, K., Rheinheimer, P., Barbaris, B., Conant,
409
W., Sáez, A. E., Betterton, E. A., 2011. Metal and Metalloid Contaminants in Atmospheric
410
Aerosols from Mining Operations. Water Air Soil Pollut. 221, 145-157.
TE D
408
Csavina, J., Taylor, M. P., Félix, O., Rine, K. P., Sáez, A. E., Betterton, E. A., 2014. Size-
412
resolved dust and aerosol contaminants associated with copper and lead smelting emissions:
413
Implications for emission management and human health. Sci. Total Environ. 493, 750-756.
AC C
EP
411
414
Davis, J. J., Morrison, A. L., Gulson, B. L., 2016. Uncovering pathways of metal
415
contamination with microscopic techniques and lead isotopic tracing. Aust. J. Earth Sci. 63, 795-
416
803.
20
ACCEPTED MANUSCRIPT
Ericson, B., Caravanos, J., Keith, J., Taylor, M. P., Frostad, J., Fuller, R., Landrigan, P., 2016.
418
The Global Burden of Lead Toxicity Attributable to Informal Used Lead-Acid Battery (ULAB)
419
Sites. Ann. Glob. Health, accepted, DOI 10.1016/j.aogh.2016.10.009
RI PT
417
Ettler, V., Johan, Z., Kříbek, B., Veselovský, F., Mihaljevič, M., Vaněk, A., Penížek, V., Majer,
421
V., Sracek, O., Mapani, B., Kamona, F., Nyambe, I., 2016. Composition and fate of mine- and
422
smelter-derived particles in soils of humid subtropical and hot semi-arid areas. Sci. Total
423
Environ. 563–564, 329-339.
SC
420
Félix, O. I., Csavina, J., Field, J., Rine, K. P., Sáez, A. E., Betterton, E. A., 2015. Use of lead
425
isotopes to identify sources of metal and metalloid contaminants in atmospheric aerosol from
426
mining operations. Chemosphere 122, 219-226.
429 430
Metall. Proc. 19, 215-219.
TE D
428
Harding, D. P., 2002. Minearal identification using a scanning electron microscope. Miner.
Hinds, W. C., 1999. Aerosol Technology: Properties, Behavior, and Measurment of Airborne Particles, 2nd Eidtion. Wiely, New York.
EP
427
M AN U
424
Humphries, K. 2015. NSW Government commits more than $13 million to reduce lead levels
432
at Broken Hill. Media release: Kevin Humphries MP Minister for Natural Resources, Lands and
433
Water
434
2015. http://www.epa.nsw.gov.au/resources/MinMedia/EPAMin150213.pdf
435
05.01.2017).
436
AC C
431
Minister
for
Western
NSW,
13th
February (accessed
Gulson, B. L., 1986. Lead isotopes in mineral exploration. Elsevier: Amsterdam.
21
ACCEPTED MANUSCRIPT
Gulson, B. L., Mizon, K. J., Law, A. J., Korsch, M, J., Davis, J. J., 1994a. Source and
438
Pathways of Lead in Humans from the Broken Hill Mining Community – An Alternative Use of
439
Exploration Methods. Econ. Geol. 89, 889 – 908.
RI PT
437
Gulson, B. L., Davis, J. J., Mizon, K. J., Korsch, M. J., Law, A. J., Howarth, D., 1994b. Lead
441
Bioavailability in the Environment of Children: Blood Lead Levels in Children Can Be Elevated
442
in a Mining Community. Arch. Environ. Health 49, 326-331.
SC
440
Gulson, B. L., Mizon, K. J., Davis, J. J., Palmer, J. M., Vimpani, G., 2004. Indentification of
444
sources of lead in children in a primary zinc-lead smelter environment. Environ. Health Perspect.
445
112, 52 – 60.
M AN U
443
Kristensen, L. J., Taylor, M. P., Morrison, A. L., 2015. Lead and zinc dust depositions from
447
ore trains characterised using lead isotopic compositions. Environ. Sci. Process. Impacts 17, 631-
448
637.
TE D
446
Kristensen, L. J., Taylor, M. P., 2016. Unravelling a ‘miner’s myth’ that environmental
450
contamination in mining towns is naturally occurring. Environ. Geochem. Health 38, 1015-1027.
451
Kristensen, L. J., Taylor, M. P., Evans, A. J., 2016. Reply to Gulson’s comments on ‘Tracing
452
changes in atmospheric sources of lead contamination using lead isotopic compositions in
453
Australian red wine’. Chemosphere 154, 40-47.
455 456 457
AC C
454
EP
449
Lanphear, B. P., 2015. The Impact of Toxins on the Developing Brain. Annu. Rev. Publi. Health 36, 211-230. Lanphear, B. P., Hornung, R., Ho, M., Howard, C. R., Eberly, S., Knauf, K., 2002. Environmental lead exposure during early childhood. J. Pediatr. 140, 40-47.
22
ACCEPTED MANUSCRIPT
Lanphear, B. P., Weitzman, M., Winter, N. L., Eberly, S., Yakir, B., Emond, M., Matte, T. D.,
459
1996. Lead-contaminated house dust and urban children’s blood lead levels. Am. J. Public
460
Health 86, 1416-1421.
461 462
RI PT
458
Larsen, M. M., Blusztajn, J. S., Andersen, O., Dahllöf, I., 2012. Lead isotopes in marine surface sediments reveal historical use of leaded fuel. J. Environ. Monitor. 14, 2893-2901.
Lesjak, M., Jones, T., 2015. Lead Health Report 2014 - Children less than 5 years old in
464
Broken Hill. Population Health Unit, NSW Government, Western NSW & Far West Local
465
Health
466
http://www.fwlhd.health.nsw.gov.au/UserFiles/files/Directorates/Population%20Health/2014%2
467
0Lead%20Report.pdf (accessed 13.09.16).
District.
M AN U
SC
463
Lyle, D. M., Philips, A. R., Balding, W. A., Burke, H., Stokes, D., Corbett, S., Hall, J., 2006.
469
Dealing with lead in Broken Hill–Trends in blood lead levels in young children 1991–2003. Sci.
470
Total Environ. 359, 111-119.
472
Lynch, A. J., 1992. Broken Hill Metallurgy – A Story of Innovations in Processces, Equipment and Instruments. The AusIMM Annual Conference, Broken Hill.
EP
471
TE D
468
Mackay, A. K., Taylor, M. P., Munksgaard, N. C., Hudson-Edwards, K. A., Burn-Nunes, L.,
474
2013. Identification of environmental lead sources and pathways in mining and smelting town:
475
Mount Isa, Australia. Environ. Pollut. 180, 304-311.
476 477
AC C
473
Miranda, R. M., Andrade, M. F., Worobiec, A., Grieken, R. V., 2002. Characterisation of aerosol particles in the Sao Paulo Metropolitan Area. Atmos. Environ. 36, 345-352.
23
ACCEPTED MANUSCRIPT
Morrison, A. L., Swierczek, Z., Gulson, B. L., 2016. Visulisation and quantification of heavy
479
metal accessibility in smelter slags: The influence of morphology on availability. Environ. Pollut.
480
210, 271-281.
RI PT
478
National Measurement Institute (NMI), 2014. National Measurement Institute, Inorganic
482
Section, Method NT2.49: Determination of Acid Extractable Elements in Soils, Sediments,
483
Sludges and Solid Waste. Sdyney.
SC
481
National Pollutant Inventory (NPI), 2015a. 2014/2015 report for BROKEN HILL
485
OPERATION PTY LTD, CBH Resources – Rasp Mine – Broken Hill, NSW.
486
http://www.npi.gov.au/npidata/action/load/emission-by-individual-facility-
487
result/criteria/state/NSW/year/2015/jurisdiction-facility/1333 (accessed 19.08.16).
488
M AN U
484
National Pollutant Inventory (NPI), 2015b. 2014/2015 report for PERILYA BROKEN HILL LIMITED,
490
http://www.npi.gov.au/npidata/action/load/emission-by-individual-facility-
491
result/criteria/state/NSW/year/2015/jurisdiction-facility/125 (accessed 19.08.16).
494
National
Pollutant
Inventory
EP
493
Broken
Hill
Operations
(NPI),
2015c.
Hill,
NSW.
NPI
data
within
Broken
Hill.
New South Wales (NSW) EPA, 2016. Licence Variation of Environment Protection Licence No.
496
1&SYSUID=1&LICID=1545186 (accessed 02.11.16)
498
Broken
http://www.npi.gov.au/npidata/action/load/advance-search (accessed 23.07.16).
495
497
–
AC C
492
Perilya
TE D
489
Perilya
2688.
http://www.epa.nsw.gov.au/prpoeoapp/ViewPOEONotice.aspx?DOCID=-
Limited,
2016.
Monthly
reports:
environmental
reporting.
http://www.perilya.com.au/health--safety--environment/environment/reports (accessed 24.07.16).
24
ACCEPTED MANUSCRIPT
Pure Earth and Green Cross, 2016. The World’s Worst Pollution Problems 2016: The Toxics Beneath
501
01.11.16).
503 504 505 506
Feet.
http://worstpolluted.org/docs/WorldsWorst2016Spreads.pdf
Solomon, R. J., 1988. The richest lode: Broken Hill 1883-1988. Hale & Iremonger, Sydney, NSW.
Spear, M., Thomas, R., Sharader-Frechette, K., 2015. Commentary: Flawed Science Delays Smelter Cleanup and Worsens Health. Account. Res. 22, 41-60.
Standards Australia, 2003. Australian/New Zealand 3580.10.1:2003. Determinationof −
508
http://infostore.saiglobal.com/store/details.aspx?ProductID.373364.
Method.
Stern, H., de Hoedt, G., Ernst, J., 2000. Objective classification of Australian climates. Australian Bureau of Meteorology, Melbourne.
TE D
512
Gravimetric
Sullivan, M., 2014. Tainted Earth: Smelters, Public Health and the Environment. New Brunswick (US): Rutgers University Press.
EP
511
Matter
−
Particulate
510
Matter
Deposited
507
509
(accessed
SC
502
Our
RI PT
500
M AN U
499
Sullivan, M., Green, D., 2016. Misled about lead: an assessment of online public health
514
education material from Australia’s lead mining and smelting towns. Environ. Health 15:1. doi:
515
10.1186/s12940-015-0085-9.
516
AC C
513
TA Luft, 2002. Technical Instructions on Air Quality Control. In: First General Administration
517
Regulation
Pertaining
the
Federal
Immission
Control
518
http://www.bmub.bund.de/fileadmin/bmu-
519
import/files/pdfs/allgemein/application/pdf/taluft_engl.pdf (accessed 10.03.15).
Act.
25
ACCEPTED MANUSCRIPT
Taylor, M. P., Schniering, C., 2010. The public minimization of the risks associated with
521
environmental lead exposure and elevated blood lead levels in children, Mount Isa, Queensland,
522
Australia. Arch. Environ. Occup. Health 65, 45-48.
RI PT
520
Taylor, M. P., Davies, P. J., Kristensen, L. J., Csavina, J. L., 2014a. Licenced to pollute but not
524
to poison: The ineffectiveness of regulatory authorities at protecting public health from
525
atmospheric arsenic, lead and other contaminants resulting from mining and smelting operations.
526
Aeolian Res. 14, 35-52.
SC
523
Taylor, M. P., Winder, C., Lanphear, B. P., 2014b. Australia's leading public health body
528
delays action on the revision of the public health goal for blood lead exposures. Environ. Int. 70,
529
113-117.
M AN U
527
Taylor, M. P., Mould, S. A., Kristensen, L. J., Rouillon, M., 2014c. Environmental arsenic,
531
cadmium and lead dust emissions from metal mine operations: Implications for environmental
532
management, monitoring and human health. Environ. Res. 135, 296-303.
534
Taylor, M. P., 2015. Atmospherically deposited trace metals from bulk mineral concentrate port operations. Sci. Total Environ. 515-516, 143-152.
EP
533
TE D
530
Thompson, A. J., Hamlet, W. M., Thomas, J., 1893. Report of Board Appointed to Inquire into
536
the Prevalence and Prevention of Lead Poisoning at the Broken Hill Silver-Lead Mines to the
537
Honorable the Minister for Mines and Agriculture. Legislativ Assembly, New South Wales.
538 539
AC C
535
Thornton, I., 1996. Impacts of mining on the environment; some local, regional and global issues. Appl. Geochem. 11, 355-361.
26
ACCEPTED MANUSCRIPT
540 541
Tong, S. L., Schirnding, Y. E. von., Prapamontol, T., 2000. Environmental lead exposure: a public health problem of gobal dimensions. Bull. World Health Organ. 78, 1068-1077. Townsend, T. A., Yu, Z., McGoldrick, P., A. Hutton, J., 1998. Precise lead isotope ratios in
543
Australian galena samples by high resolution inductively coupled plasma mass spectrometry. J.
544
Anal. At. Spectrom. 13, 809-813.
RI PT
542
Tye, A. M., Hodgkinson, E. S., Rawlins, B. G., 2006. Microscopic and chemical studies of
546
metal particulates in tree bark and attic dust: evidence for historical atmospheric smelter
547
emissions, Humberside, UK. J. Environ. Monit. 8, 904-912.
551 552 553 554 555 556
M AN U
Williamson, B. J., Rollinson, G., Pirrie, D., 2013. Automated Mineralogical Analysis of PM10: New Parameters for accessing PM Toxicity. Environ. Sci. Technol. 47, 5570-5577.
TE D
550
Electron Probe Microanalysis of Microscopical Particles. X-Ray Spectrom. 20, 51-62.
Woodward-Clyde Pty Limited, 1993. Evaluation of environmental lead at Broken Hill. Report to the Environment Protection Authority.
EP
549
van Borm, W. A., Adams, F. C., 1991. A Standarless ZAF Correction for Semi-quantitative
Woodward, O. H., 1965. A review of the Broken Hill Lead-Silver-Zinc Industry. West Publishing Coroporation Pty. Ltd, Sydney, NSW.
AC C
548
SC
545
World Health Organization (WHO), 2000. Air Quality Guidelines for Europe: Second Edition.
557
Regional
558
http://www.euro.who.int/__data/assets/pdf_file/0005/74732/E71922.pdf (accessed 02.11.16)
559 560
Office
for
Europe,
Copenhagen.
Yang, K., Cattle, S. R., 2015. Bioaccessibility of lead in urban soil of Broken Hill, Australia: A study based on in vitro digestion and the IEUBK model. Sci. Total Environ. 538, 922-933.
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List of figure captions
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Figure 1. Study area and sites for dust gauge, tailings dump and gossan samples.
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Figure 3. Linear relationship between total dust Pb and bioaccessible Pb loading values.
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Figure 4. Lead isotopic compositions of dust in Broken Hill. (a) comparison of sites, (b)
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comparison between spring/summer and winter samples. The averaged lead isotopic composition
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data of ore body in Broken Hill is from Cooper et al. (1969), Gulson (1986) and Townsend et al.
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(1998). The leaded gasoline and 1991/1992 dust Pb isotopic data are from Gulson et al. (1994a).
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The background soil values are from Kristensen and Taylor (2016). Standard deviations of the Pb
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Figure 5. Scanning electron micrographs taken using back-scattered electron mode (BSE) of
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Broken Hill Pb bearing particles. Energy-dispersive X-ray spectroscopy (EDS) results of dust
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gauge samples, tailings and gossan samples are also shown. The concentrations of elements are
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Video 1. Video showing dusts blowing off the lead and zinc ore pile at the head of the Perilya
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Mine in Broken Hill, NSW, Australia (dated 1 March 2015).
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Multiple approaches applied to identify sources of atmospheric dust contamination Broken Hill Pb in dust is highly bioaccessible with a mean of 68 % Former sources of contamination e.g. leaded gasoline are no longer significant Current mining activities contribute Pb-rich dust to the urban environment
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