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Comparative studies of atmospheric trace elements: improvements in air quality near a copper smelter
Science of the Total Environment 332 (2004) 39 – 49 www.elsevier.com/locate/scitotenv
Comparative studies of atmospheric trace elements: improvements in air quality near a copper smelter F. Beavington a,b,*, P.A. Cawse c, Amiette Wakenshaw d a
Onetime Bayero University, Kano, Nigeria King’s College, University of London, UK c Onetime AEA Technology, Environmental Safety Division, Harwell Laboratory, Oxon, UK d New South Wales Environment Protection Authority, Wollongong 2500, Australia b
Received 18 August 2003; received in revised form 4 March 2004; accepted 17 April 2004
Abstract Measurements of trace element concentrations, including heavy metals in the atmosphere near a copper smelter in Port Kembla, New South Wales, have shown improvements in air quality, attributed mainly to modernisation of the plant, with more than 85% decrease (for each element) in airborne Cr, Zn, Se, Ag, Cd, Sb, Au and Pb, associated with 74% reduction in Cu concentration. This data was obtained by analysis of air particulate sampled in 2001 – 2002 for comparison with measurements at the same location in 1978. As expected, measurements of Na and Cl derived from the marine aerosol at this coastal location showed no corresponding change. The recent analysis of air particulate shows significant correlations between the monthly concentrations of Cu, Zn, Se, Ag and Pb, associated with industry, hence giving a high enrichment in airborne particulate by reference to the element/Sc ratios in ‘average’ soil. These enrichments, shown by heavy metals in particular, were two orders of magnitude greater than the values recorded in the atmosphere of rural areas; however, it is clear that air quality at Port Kembla is much improved and predominantly related to the modernisation of the smelter. D 2004 Elsevier B.V. All rights reserved. Keywords: Copper smelter; Emissions; Trace metals; Environmental contamination; Background levels
1. Introduction Previous studies have shown that the entire environment in the vicinity of the copper smelter at Port Kembla, Australia, (surface soil, herbage, vegetable gardens, rivulet and harbour water and rainwater) was contaminated by heavy metals, es* Corresponding author. Church Farm House, Ryarsh, Kent ME19 5LB, UK. Tel./fax: +44-1732-845791. E-mail address: [email protected] (F. Beavington). 0048-9697/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2004.04.016
pecially Cu, Zn, Cd and Pb (Beavington, 1973, 1975a,b,c, 1977). These studies also showed that the concentration of Fe in herbage and rainwater was highest near the open-hearth furnace of the adjacent steelworks (Fig. 1). Port Kembla (latitude 341/2jS) is a southern suburb of the City of Wollongong (pop. 178,000) in New South Wales, 72 km south of Sydney, and where the smelter is the largest in the southern hemisphere. The investigations in the 1970s also found inverse correlations between distance from the smelter and the content of heavy metals in surface soil, herbage,
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Fig. 1. Location of heavy industry complex and residential area of Port Kembla.
lettuce and supporting soil and rainwater. Soil profile samples showed that the contaminant metals were concentrated in the 0 –15 cm layer. Confirmation that the smelter is the dominant source of heavy metal contamination is shown by the pattern of extractable soil Cu over the Wollongong City area (Fig. 2). This map (Fig. 2), hitherto unpublished, is based on surface soil samples (0 –15 cm) taken at the intersections of a 200m grid covering the city area, as reported by Beavington (1973). Roads and built-up areas in the city were excluded from the sampling, and the outlying farmland within the city boundary was sampled at less frequent intervals. Within 1km radius of the smelter, exceptionally high levels of extractable soil Cu of 1380, 1360, 700, 620, 514, 505, 395, 312 and 280 Ag g 1 were found. Beyond this radius values fell steeply with distance from the smelter so that over the northern and western areas
of the city the content of extractable soil Cu was similar to that of the rural control area, on the coast 35 km to the south, with similar soil and with an average value of 5.3 Ag g 1 extractable soil Cu (Beavington, 1973). A study was also made at Port Kembla, in 1978, but not reported, of 26 trace elements in the air, namely, Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Ag, Cd, In, Sb, I, Au, Hg and Pb, sampled at a site in the residential area only 150 m from the base of the chimney of the copper smelter (Fig. 1). Sampling was continuous for a 3-month period (February to April). The smelter continued to operate until February 1995 when it was closed. Modernisation to world’s best practice with up-to-date precipitators and water quality regime was carried out in 1998 and 1999. The smelter then opened as a new company in February 2000
F. Beavington et al. / Science of the Total Environment 332 (2004) 39–49
Fig. 2. Distribution of easily extractable copper in surface soil (0 – 15 cm) over the Wollongong City area.
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(and ceased production again in September 2003 with just maintenance and management staff on site). During the 1990s, modern equipment to reduce atmospheric pollution was also installed in the steelworks, though the 1970s studies showed, from the deposition and accumulation of Cu in the environment, that compared with the smelter, the steelworks did not make a significant contribution of heavy metals to the atmosphere other than Fe. For a number of years, there had been concern for the health of children at Port Kembla Primary School which is located close to the smelter (Fig. 1). This concern led to the closure of the school in 1999. Roberts et al. (1974) reported on the effect of Pb on children in the vicinity of two secondary lead smelters in Toronto, Canada and showed that Pb contamination decreased sharply with distance from the smelter source. The purpose of the present study was to compare the recent content of heavy metals and other trace elements in the atmosphere in the vicinity of the smelter with the concentrations of the same elements found in 1978. To this end, in April 2001, a sampling station was set up at the same site. The same type of sampling equipment was used as in 1978, and the same analytical methods were used for most of the elements. Again, sampling was continuous, though this study covered a 12-month period, from May 2001 to April 2002. Studies have been made from the University of Wollongong on heavy metal contamination of local marine environments in the vicinity of Port Kembla (Chiaradia et al., 1997; Payne et al., 1997). A review of work on Port Kembla harbour from 1975 by Zhijia and Morrison (2001) showed a marked reduction in heavy metal contamination of the harbour water and its aquatic life as a result of controls on the discharge of industrial effluent.
2. Methods of sampling and analysis The method of sampling used was that described by Cawse and Peirson (1972). Air particulate was collected continuously on cellulose filters (Whatman 40 grade), of 6-cm diameter, held in a polypropylene duct at 1.5 m above ground level. Air was drawn through the filter by means of an electrically driven low suction
pump. The airflow rate, of about 10.5 m3 every 24 h, was measured exactly by a diaphragm flowmeter connected to the outflow manifold of the pump. Filters were changed half monthly and the two were analysed together as a single sample. The sampling equipment was mounted on a timber frame and polythene gloves and plastic forceps were used in the handling of the filter papers to avoid contamination. Instrumental neutron activation analysis (INAA), as described by Salmon (1975) and Salmon and Cawse (1990), and used routinely at the UK Atomic Energy Authority, Harwell Laboratory, was the preferred technique for the analysis of most elements in the 1978 study, supported by atomic absorption spectrometry for Cu, Ni and Cd, with X-ray fluorescence for Pb. Following the closure of the nuclear reactor at Harwell, the reactor at Imperial College, University of London, was used for INAA of the air filters from the 2001 –2002 study. The accuracy of analysis was validated by measurements on a standard reference material, SRM 1571, orchard leaves, from the National Bureau of Standards/National Institute of Standards and Technology. In addition, the application in the 1970s of INAA to multielement analysis of air particulate involved comparison with results from gamma-photon activation, atomic absorption and X-ray fluorescence methods (Cawse, 1976). During this comparison, the accuracy of INAA was established and results were within 5% of the 15 certified or indicated concentrations in the SRM 1571. The analysis of K, Ni, Cd and Pb was made by high-resolution inductively coupled plasma mass spectrometry, for which the Laboratory of the (UK) Government Chemist used gas works contaminated soil as reference material (LGC 6144). Samples of blank (unexposed) Whatman 40 filter papers were submitted to both laboratories and taken into account in the calculation of the results. Both the Government Chemist and Imperial College laboratories conform to UKAS methodology in respect of their quality control. Soil samples for the measurement of Cu were gently ground and passed through a 2-mm sieve of nylon mesh and aluminium frame; EDTA (0.02/L) was the extractant, as used by Purves and Mackenzie (1969), and determination was by atomic absorption spectrometry.
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3. Results and discussion 3.1. Comparison of the 1978 and 2001 – 2002 results and examination of ratios between elements Table 1 shows the average monthly concentrations at Port Kembla of 26 elements in the air for the year, May 2001 to April 2002, and separately, for the 3 months February, March and April 2002, and for the corresponding 3-month period in 1978, allowing a direct comparison between the average concentrations for these quarters after 24 years. The percentage
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uncertainty for analysis of this data is also included in Table 1. Table 1 also shows the atmospheric content of trace elements at two background sites remote from industry and exposed to a strong maritime influence: Cape Grim (latitude 40jS) at the northwest tip of Tasmania, shown on Fig. 1, a monitoring station of the Australian Nuclear Science and Technology Organisation (Cohen et al., 2000) and Collafirth (latitude 60jN) in the Shetland Isles, northern Scotland, a monitoring station of the UK Atomic Energy Authority (Cawse, 1977). Cape Grim, therefore, is in the path of prevail-
Table 1 Concentrations of elements in air at Port Kembla, NSW, Australia 2001 – 2002 and 1978 and comparison with background sites 1
2
3
4
5
6
Collafirth Shetland Isles 60jN
Cape Grim NW Tasmania 41jS
Percentage reduction in concentration:
Jan – Dec 1976
1992 – 1998 average
column 2 as a percentage of column 3
ng kg
121 36 25 116 – 8 24 18 11 32 28 21 22 26 14 51 8 18 – 4.7 14 4.7 9 3.3 – 2.4
1550 270 66 2200 760 300 0.011 1.4 0.39 2.7 52 0.062 <2 14 11 < 0.5 0.44 9.9 0.028 < 0.9 < 0.04 0.35 <1 0.004 < 0.008 14
Port Kembla 341/2jS
May 2001 – April 2002 ng kg
Na Mg Al Cl K Ca Sc V Cr Mn Fe Co Ni Cu Zn As Se Br Ag Cd In Sb I Au Hg Pb
1
Feb – Apr 2002
Feb – Apr 1978
aira; Percentage uncertainty of analysis in parentheses
2480 (2.2) 229 (8.0) 210 (3.3) 4397 (2.2) 131 (2.5) 725 (13) 0.046 (4.9) 1.7 (8.5) 1.3 (8.0) 7.3 (2.5) 389 (4.6) 0.22 (8.5) 34.4 (5.0) 200 (7.3) 157 (2.4) 13.5 (3.9) 4.0 (11) 11.1 (3.8) 0.4 (17) 1.8 (5.0) < 0.2 (4.7) 0.67 (5.0) 0.87 (13) 0.0015 (9.0) < 0.4 38.8 (5.0)
3109 259 147 5690 91 735 0.031 1.5 1.4 5.8 353 0.19 6.8 238 226 14.7 3.7 12.8 < 0.4 4.0 0.17 0.61 0.67 0.0013 < 0.4 47.3
2570 (6.1) 723 (10) 586 (4.2) 4900 (5.1) < 660 9200 (15) 0.13 (4.0) 8.4 (5.4) 13 (8.3) 18 (4.5) 1280 (5.5) 0.90 (7.0) 31 (5.3) 920 (11) 1600 (5.5) 29 (9.3) 49 (6.9) 71 (6.0) 15.6 (20) 86 (5.0) 1.2 (14) 12.9 (2.9) 7.4 (20) 0.04 (18) 0.62 2000 (5.4)
1
Results are quarterly or annual average concentrations for the period stated. a ng kg 1 1.226 = ng m 3, since 1 m3 air at 15 jC, 760 mm Hg (Standard Cubic Metre) = 1.226 kg.
aira
816 – 12.2 1223 32 31 – 0.82 0.08 0.57 3.3 0.2 0.33 1.1 0.98 – – 2.1 – – – – – – – 0.90
Na Mg Al Cl K Ca Sc V Cr Mn Fe Co Ni Cu Zn As Se Br Ag Cd In Sb I Au Hg Pb
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ing winds from the Southern Ocean, and the Shetland Isles from those of the North Atlantic. The figures for Collafirth are for the year 1976 and cover the same range of elements as for Port Kembla, the analysis being carried out in the same laboratory. The data for Cape Grim are averages for 1992 –1998 and are for 15 trace elements that include the heavy metals, Cr, Fe, Ni, Cu, Zn and Pb. Data shown in Figs. 3 and 6 also include a further background site: Bagauda, at latitude 11jN in the rural savanna of northern Nigeria (Beavington and Cawse, 1978). The land use of this region is peasant arable farming with manual labour only and transport to and from the small, scattered native villages is by donkeys (Beavington and Varley, 2000). The sampling and analytical methods for both Northern Hemisphere sites were the same as used for the Port Kembla study. It may be noted that although both Collafirth and Bagauda are very different in respect of their location and proportion of atmospheric elements derived from ocean and from land, their content of heavy metals is both low and similar (Fig. 3), owing to long distance dispersion of pollutants (Peirson et al., 1974). The contents of the
elements in the atmosphere at these background sites are only expected to show variation over the long term in response to climate change that affects rainfall, wind and temperature. The percentage differences for element concentrations at Port Kembla between 1978 and 2001– 2002 (Table 1, column 4) show a dramatic decrease in most elements associated with industrial pollution [decreases in Mg, Al, Ca (Table 1) could be attributed to improved controls in handling the ore]. Thus, in 2002, on average, there is less than 10% of the Se, Cd, Sb, I and Pb in the air than there was in 1978, less than 20% of theV, Cr, Zn and Br, less than 30% of the Cu and Fe and only about half of the As, compared with 1978. By comparison with Port Kembla, the purity of the air at Cape Grim is evident from the concentrations of Cr, Fe, Ni, Cu, Zn and Pb (Table 1) which are two orders of magnitude lower than at Port Kembla even since the modernisation of the smelter. Arimoto et al. (1989) found air of still greater purity at a site in the remote Pacific islands of Samoa (latitude 14jS) where concentrations of Cu and Pb were two orders of magnitude lower that at Cape Grim.
Fig. 3. Comparison of the atmospheric content of trace elements between Port Kembla and Cape Grim, NW Tasmania and two further background sites, Collafirth, Shetland Isles and Bagauda, West African savanna.
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The average concentration of atmospheric Pb reduces from 2000 ng kg 1 air during February to April 1978 to 47.3 ng kg 1 air over the same 3 months in 2002 and 39.8 ng kg 1 for the 2001 – 2002 year. These concentrations may also be compared with the annual average values of 0.9, 14 and 12 ng kg 1 air for rural locations at Cape Grim, Collafirth and Bagauda, respectively (Table 1 and Fig. 3). The two main sources of atmospheric Pb in Port Kembla in 1978 would have been emissions from the unmodernised smelter and lead from vehicle exhausts. The addition of lead to petrol in Australia ceased in 1988, except for older vehicles. Consequently, there was no need for the Br-enriched ethyl fluid additive which had a Pb/Br ratio of 2.8 (Lininger et al., 1966) to be used in petrol. The content of Br in the air fell sharply between 1978 and 2001 –2002. Table 2 shows that the Pb/Br ratio of 28 at Port Kembla in 1978 contrasts with 3.6 for 2001– 2002 (3.7 for February to April 2002). Exhaust emissions from leaded fuel, therefore, were a minor contributor relative to emissions of Pb from the smelter which had resulted in the former massive concentration of Pb in air particulate prior to the modernisation of the smelter. Measurements of Fe, Cu, Zn and Pb in the air near the smelter carried out by the laboratory of the smelter company, Port Kembla Copper, for the period April 2001 to March 2002 agree with the improvement in air
Table 2 Comparison of element ratios in rainwater, air and copper ore at Port Kembla Element Rainwater Air monthly Air average ratios mean of average for for Feb – 13 sites 2001 – 2002 April 1978 (Beavington, 1977)
Copper orea from
Cu/Zn Cu/Pb Cu/Cd Zn/Pb Zn/Cd Pb/Cd Pb/Br Fe/Al Fe/Pb Cl/Na
145 1000 290 308 – – 0.5 3.3 – – – – – – 321 11.3 340 300 – –
a
2.4 6.3 133 2.6 55 21 – – 12.5 –
1.3 5.0 111 3.9 87 22 3.6 1.9 9.8 1.8
0.6 0.5 10.7 0.8 18.6 23 28 2.2 0.64 1.9
Cobar N Parkes source source
Analysis of copper ore from the two main sources used by the smelter.
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quality as found in this study. Their sampling station, although in the same close vicinity to the smelter, was more exposed to it. A high-volume sampler was used that operated for short periods only, and the analytical method was different with only four elements, Fe, Cu, Zn and Pb, determined. Nevertheless, the concentrations of these elements in air, although higher by a factor of 1.2 to 3.0, are in similar order of concentration as recorded by the present study for the period 2001– 2002, whilst the element ratios in air particulate of Cu/Zn 1.8, Cu/Pb 7.4, Zn/Pb 4.0 and Fe/Pb 11.7 are comparable with those of Table 2. The ratios between certain heavy metals (Table 2) in air particulate for 2001– 2002 are close to those recorded from earlier analysis of rainwater and dry deposition, collected for 12 months at three locations within 610 m of the copper smelter (Beavington, 1977). Thus, the Cu/Zn, Cu/Cd and Pb/Cd ratios in air particulate and rainwater (i.e., the total deposition) are comparable for the historic 1978 data and recent measurements and thus indicate consistency in the spectrum of elements in air particulate emitted from the smelter. However, the relatively high content of both Cd and Pb in air in 1978 (Table 1) prior to the upgrading of the smelter would explain the lower ratios for Cu/Pb, Cu/Cd, Zn/Pb, Zn/Cd and Fe/ Pb than those recorded in 2001– 2002 (Table 2). The influence of the maritime aerosol is evident from the Cl/Na ratios in the range 1.7 to 1.9 for the year 2001– 2002, giving an average ratio of 1.8 which is the same as in seawater (Mason, 1966). A comparison of the ratios of metals in the copper ore from both its main sources, Cobar and North Parkes, with those for metals in the air during 2001 – 2002 (Table 2) show that copper is well removed from the ore. In addition, the relatively low ratio of 1.9 for Fe/Al in air for 2001– 2002, when compared with the much higher ratios in the ore samples of 11.3 (North Parkes) and 321 (Cobar), indicates little contribution of dust from ore handling. 3.2. Monthly variations in airborne trace elements Fig. 4 shows the monthly variations in the atmospheric content of elements of industrial origin for the year 2001– 2002, whilst Fig. 5 shows the less pronounced variations for these elements derived directly from terrestrial and marine sources. The smelter
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Fig. 4. Monthly variation in the atmospheric content of elements mainly of industrial origin at Port Kembla (May 2001 to April 2002).
Fig. 5. Monthly variations in the atmospheric content of elements mainly of non-industrial origin at Port Kembla (May 2001 to April 2002).
F. Beavington et al. / Science of the Total Environment 332 (2004) 39–49
underwent annual maintenance during the second half of July and part of August 2001. This was followed by an apparent marked increase in smelting activity in September when there was a four to fivefold increase in many airborne metals over the July recordings. As would be expected, these variations did not occur in the atmospheric content of Na, Cl, Sc, V, Mn and Br (Fig. 5); these elements being mainly of non-industrial origin. There was a further sharp decline in January in the atmospheric content of the eleven metals shown in Fig. 4, but again, no change in the elements of Fig. 5. The smelter was not closed in this holiday month and although meteorological data (recorded at the University of Wollongong) showed there were days of high temperatures (31 – 35 jC maximum), there was no unusual weather. The obvious explanation for this improvement in air quality is a reduction in the amount of ore being smelted. During half of the study period, November 2001 to April 2002, when higher rainfall was recorded (742 mm) compared with 381 mm in the winter six months, onshore winds are more frequent and form 77% of all wind directions from December to February. In these 3 months, concentrations of Na and Cl in air were approximately 2.8 times greater than for the three corresponding winter months when offshore winds predominate limiting marine aerosol from sea spray. Br follows the same pattern. There were, however, no apparent seasonal variations for the elements derived from the land or for the heavy metals; the reduction of the latter being apparently due to reduced smelting. The supply and distribution of airborne contaminant metals in an industrial city are affected by a number of factors. Emissions from large smelters are supplemented by incineration, minor industrial sources, vehicles, domestic chimneys and bonfires, whilst distribution is affected by buildings and turbulence, especially in the immediate vicinity of the smelter chimney. Other sources, including industrial deposits and pockets of buried refuse, produce local variations in the soil content of heavy metals, as shown in the case of Cu (Fig. 2). In a different situation of a lowland rural area, Little and Martin (1972) showed, from a study of soil and vegetation up to some 15 km from the smelter at Avonmouth, UK, that the distribution of Zn, Pb and Cd was strongly influenced by prevailing winds.
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3.3. Enrichment factors and correlations The application of air particulate enrichment factors (EF) to demonstrate the influence of industrial activities on air quality was made in the 1970s when neutron activation of air filters could provide a comprehensive multielement analysis (Rahn, 1972; Peirson et al., 1974; Beavington and Cawse, 1978; Greenberg et al., 1978). The concentrations of elements recorded in air particulate are referred to a single element selected to represent a natural source material such as soil. Selection of a reference element to assess the contribution to the aerosol from soil or Earth’s crust may be made from Al, Ce, Sc, Si or Ti, and in the present study, Sc is the marker element.Thus, the EF for an element X=[X/Sc in aerosol]/[X/Sc in average soil (Bowen, 1966)]. The differences in enrichments of 17 elements in air particulate at Port Kembla are illustrated in Fig. 6 for high, intermediate and low EF groups and reveal order of magnitude variation, as expected from an industrial area. Further, a comparison with EF values recorded previously at a rural location in northern Nigeria (Beavington et al., 1978) indicates the extent of heavy metal pollution by industry at Port Kembla. The mechanism of enrichment in industrial atmospheres has been related to the high volatility of chalcophilic elements, e.g., Zn, Se, Cd and Pb, compared to those in the lithophilic group represented by Al, Sc, Mn and Fe. Consequently, the volatile metals arising from smelting and other combustion processes (e.g., incineration, use of fossil fuels, automobile exhaust) condense on the smaller size fraction of air particulate having relatively high surface area (Heindrycks, 1976). In respect of the atmospheric concentrations for 18 of the elements measured at Port Kembla (Table 1), correlations between pairs at P < 0.001 and P < 0.01 (Table 3) were predominant for Cu, Zn, As, Se and Pb, all with EF>100; none of these elements correlated with those from non-industrial origins, i.e., Na, Cl and Br from the marine aerosol, or Al and Sc brought into suspension from the land by wind, and hence without enrichment. At P < 0.05, correlations were found between 19 pairs of elements, of which 16 were for elements with industrial associations namely V, Co, Ni, Cd, Sb and Pb. The only correlation
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Fig. 6. Comparison of air particulate enrichment factors.
involving Fe in air, at either the 0.01% or the 0.1% level of significance, is with V (Table 3); there being no correlation of Fe with the heavy metals, the high enrichment of which (Fig. 6) is attributed to emissions from the smelter. This implies that the steelworks does
Table 3 Significance of correlations between pairs of elements in air particulate at Port Kembla 2001 – 2002 P < 0.001
P < 0.01
P < 0.05
r = 0.823
r = 0.710
r = 0.575
Pb – Cu Pb – Zn Pb – As
Pb – Se
Cu – As
Cu – Se Cu – Zn
Pb – Ni Pb – Sb Pb – Fe Pb – V Cu – V Cu – Cd Zn – Ni Zn – Se Zn – Sb As – Ni As – V Se – Co Ni – Sb Ni – Co Sb – Fe Sb – Co Fe – Mn
Zn – As
As – Se
Fe – V Sc – Al Na – Cl Na – Br Cl – Br
Na – Mn (negative) Cl – Mn (negative)
not have an appreciable influence on airborne metals at the sampling site.
4. Conclusion The investigations of the 1970s showed that the entire environment in Port Kembla was contaminated by heavy metals. It was also shown that except for Fe, the smelter was the dominant source of this contamination and that the concentration of metals in each of these parts of the environment, surface soil, herbage, vegetable gardens, rivulet and harbour water, rainwater and air, increased nearer to the smelter. The atmosphere is of dual concern since not only is it the principal medium for the contamination of the environment but it is breathed in daily and probably ingested by the people who live and work in the area. The improved environment emissions control installed in the smelter (and also in the steelworks) has resulted in a very substantial improvement in air quality, as far as metals are concerned, and this improvement shows what could be achieved if older smelters and other metal processing facilities were upgraded using modern technologies. Even so, the heavy metal content of the atmosphere of Port Kembla is still appreciably higher than that of the rural background of the West African savanna and the maritime background of Shetland, and in particular, that of the north west Tasmanian coast.
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Acknowledgements We thank Dr. R.T. Wheway of the University of Wollongong for assistance with the 1978 sampling programme, Dr. M.E. Frost for producing the correlation matrix, Mr. E.J. Beavington for the computer graphics, Ms. Roma Beamont for cartographic assistance, Mr G.E.L. McDougall for field assistance and the Soil Studies students of Wollongong University College who, in 1971, helped with the soil sampling programme. We also acknowledge the interest and assistance of the New South Wales Environment Protection Authority.
References Arimoto R, Duce RA, Ray BJ. Concentrations, sources and air – sea exchange of trace elements in the atmosphere over the Pacific Ocean. In: Riley JP, Chester R, editors. Chemical Oceanography, vol. 10. London: Academic Press; 1989. p. 107 – 47. Beavington F. Contamination of soil with zinc, copper, lead and cadmium in the Wollongong city area. Aust J Soil Res 1973; 11:27 – 31. Beavington F. Some aspects of contamination of herbage with copper, zinc and iron. Environ Pollut 1975a;8:65 – 71. Beavington F. Heavy metal contamination of vegetables and soil in domestic gardens around a smelting complex. Environ Pollut 1975b;9:211 – 7. Beavington F. Pollution by heavy metals of rivulet and harbour water in Wollongong. Search 1975c;9:390 – 1. Beavington F. Trace elements in rainwater and dry deposition around a smelting complex. Environ Pollut 1977;13:127 – 31. Beavington F, Cawse PA. Comparative studies of trace elements in air particulate in northern Nigeria. Sci Total Environ 1978;10: 239 – 44. Beavington F, Varley JA. Letter to the editor. Geogr J 2000;166: 282 – 3. Bowen HJM. Trace elements in biochemistry. New York: Academic Press; 1966. Cawse PA, editor. Inter-comparison of analysis of air filter deposits for trace elements. AERE Harwell Rep. R8191. London: HMSO; 1976. Cawse PA. A survey of the atmospheric trace elements in the UK: results for 1976. AERE Harwell Rep. R8869. London: HMSO; 1977. Cawse PA, Peirson DH. An analytical study of trace elements in the
49
atmospheric environment. AERE Harwell Rep. R7131. London: HMSO; 1972. Chiaradia M, Chenhall BE, Depers AM, Gulson BL, Jones BG. Identification of historic lead sources in roof dust and recent lake sediments from an industrialised area: indications from lead isotopes. Sci Total Environ 1997;205:107 – 28. Cohen DD, Garton D, Stelcer E. Multi-element methods for fine particle source apportionment at the global baseline station at Cape Grim, Tasmania. Nucl Instrum Methods Phys Res 2000; 161 – 163:775 – 9. Greenberg RR, Zoller WH, Gordon GE. The contribution of refuse incineration to urban aerosols. Proc. 4th Joint Conf. Sensing Environmental Pollutants. Washington (DC): American Chemical Society; 1978. p. 817 – 20. Heindrycks R. Comparison of the mass-size functions of the elements in the aerosols of Gent industrial district with data from other areas. Some physio-chemical implications. Atmos Environ 1976;10:65 – 71. Lininger RL, Duce RA, Winchester JW, Matson WR. Chlorine, bromine, iodine and lead in aerosols from Cambridge, Massachusetts. J Geophys Res 1966;71:2457 – 63. Little P, Martin MH. A survey of zinc, lead and cadmium in soil and natural vegetation around a smelting complex. Environ Pollut 1972;3:241 – 54. Mason B. Principles of geochemistry. 3rd ed. New York: Wiley; 1966. Payne M, Chenhall BE, Murray M, Jones BG. Spatial variation of sediment-bound zinc, lead, copper and rubidium in Lake Illawarra, a coastal lagoon in eastern Australia. J Coast Res 1997;13:1181 – 91. Peirson DH, Cawse PA, Cambray RS. Chemical uniformity of airborne particulate material, and a maritime effect. Nature (Lond.) 1974;251:675 – 9. Purves D, Mackenzie EJ. Trace element contamination of parkland in urban areas. J Soil Sci 1969;20:288 – 90. Rahn KA. Study of national air pollution by combustion, Progress Report, I.NW, University of Liege, Gent, Belgium; 1972. Roberts TM, Hutchinson TC, Paciga J, Chattopadhyay A, Jervis RE, Van Loon J, Parkinson DW. Lead contamination around secondary smelters: estimation of dispersal and accumulation by humans. Science 1974;186:1120 – 3. Salmon L. Instrumental neutron activation analysis in environmental studies of trace elements. AERE Harwell Rep., R7859. London: HMSO; 1975. Salmon L, Cawse PA. Instrumental neutron activation analysis. In: Smith KA, editor. Soil analysis: modern instrumental techniques, 2nd ed. New York: Marcel Dekker; 1990. p. 377 – 423. Zhijia HE, Morrison RJ. Changes in the marine environment of Port Kembla Harbour, NSW, Australia, 1975 – 1995: a review. Mar Pollut Bull 2001;42:193 – 201.
Comparative studies of atmospheric trace elements: improvements in air quality near a copper smelter F. Beavington a,b,*, P.A. Cawse c, Amiette Wakenshaw d a
Onetime Bayero University, Kano, Nigeria King’s College, University of London, UK c Onetime AEA Technology, Environmental Safety Division, Harwell Laboratory, Oxon, UK d New South Wales Environment Protection Authority, Wollongong 2500, Australia b
Received 18 August 2003; received in revised form 4 March 2004; accepted 17 April 2004
Abstract Measurements of trace element concentrations, including heavy metals in the atmosphere near a copper smelter in Port Kembla, New South Wales, have shown improvements in air quality, attributed mainly to modernisation of the plant, with more than 85% decrease (for each element) in airborne Cr, Zn, Se, Ag, Cd, Sb, Au and Pb, associated with 74% reduction in Cu concentration. This data was obtained by analysis of air particulate sampled in 2001 – 2002 for comparison with measurements at the same location in 1978. As expected, measurements of Na and Cl derived from the marine aerosol at this coastal location showed no corresponding change. The recent analysis of air particulate shows significant correlations between the monthly concentrations of Cu, Zn, Se, Ag and Pb, associated with industry, hence giving a high enrichment in airborne particulate by reference to the element/Sc ratios in ‘average’ soil. These enrichments, shown by heavy metals in particular, were two orders of magnitude greater than the values recorded in the atmosphere of rural areas; however, it is clear that air quality at Port Kembla is much improved and predominantly related to the modernisation of the smelter. D 2004 Elsevier B.V. All rights reserved. Keywords: Copper smelter; Emissions; Trace metals; Environmental contamination; Background levels
1. Introduction Previous studies have shown that the entire environment in the vicinity of the copper smelter at Port Kembla, Australia, (surface soil, herbage, vegetable gardens, rivulet and harbour water and rainwater) was contaminated by heavy metals, es* Corresponding author. Church Farm House, Ryarsh, Kent ME19 5LB, UK. Tel./fax: +44-1732-845791. E-mail address: [email protected] (F. Beavington). 0048-9697/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2004.04.016
pecially Cu, Zn, Cd and Pb (Beavington, 1973, 1975a,b,c, 1977). These studies also showed that the concentration of Fe in herbage and rainwater was highest near the open-hearth furnace of the adjacent steelworks (Fig. 1). Port Kembla (latitude 341/2jS) is a southern suburb of the City of Wollongong (pop. 178,000) in New South Wales, 72 km south of Sydney, and where the smelter is the largest in the southern hemisphere. The investigations in the 1970s also found inverse correlations between distance from the smelter and the content of heavy metals in surface soil, herbage,
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Fig. 1. Location of heavy industry complex and residential area of Port Kembla.
lettuce and supporting soil and rainwater. Soil profile samples showed that the contaminant metals were concentrated in the 0 –15 cm layer. Confirmation that the smelter is the dominant source of heavy metal contamination is shown by the pattern of extractable soil Cu over the Wollongong City area (Fig. 2). This map (Fig. 2), hitherto unpublished, is based on surface soil samples (0 –15 cm) taken at the intersections of a 200m grid covering the city area, as reported by Beavington (1973). Roads and built-up areas in the city were excluded from the sampling, and the outlying farmland within the city boundary was sampled at less frequent intervals. Within 1km radius of the smelter, exceptionally high levels of extractable soil Cu of 1380, 1360, 700, 620, 514, 505, 395, 312 and 280 Ag g 1 were found. Beyond this radius values fell steeply with distance from the smelter so that over the northern and western areas
of the city the content of extractable soil Cu was similar to that of the rural control area, on the coast 35 km to the south, with similar soil and with an average value of 5.3 Ag g 1 extractable soil Cu (Beavington, 1973). A study was also made at Port Kembla, in 1978, but not reported, of 26 trace elements in the air, namely, Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Ag, Cd, In, Sb, I, Au, Hg and Pb, sampled at a site in the residential area only 150 m from the base of the chimney of the copper smelter (Fig. 1). Sampling was continuous for a 3-month period (February to April). The smelter continued to operate until February 1995 when it was closed. Modernisation to world’s best practice with up-to-date precipitators and water quality regime was carried out in 1998 and 1999. The smelter then opened as a new company in February 2000
F. Beavington et al. / Science of the Total Environment 332 (2004) 39–49
Fig. 2. Distribution of easily extractable copper in surface soil (0 – 15 cm) over the Wollongong City area.
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(and ceased production again in September 2003 with just maintenance and management staff on site). During the 1990s, modern equipment to reduce atmospheric pollution was also installed in the steelworks, though the 1970s studies showed, from the deposition and accumulation of Cu in the environment, that compared with the smelter, the steelworks did not make a significant contribution of heavy metals to the atmosphere other than Fe. For a number of years, there had been concern for the health of children at Port Kembla Primary School which is located close to the smelter (Fig. 1). This concern led to the closure of the school in 1999. Roberts et al. (1974) reported on the effect of Pb on children in the vicinity of two secondary lead smelters in Toronto, Canada and showed that Pb contamination decreased sharply with distance from the smelter source. The purpose of the present study was to compare the recent content of heavy metals and other trace elements in the atmosphere in the vicinity of the smelter with the concentrations of the same elements found in 1978. To this end, in April 2001, a sampling station was set up at the same site. The same type of sampling equipment was used as in 1978, and the same analytical methods were used for most of the elements. Again, sampling was continuous, though this study covered a 12-month period, from May 2001 to April 2002. Studies have been made from the University of Wollongong on heavy metal contamination of local marine environments in the vicinity of Port Kembla (Chiaradia et al., 1997; Payne et al., 1997). A review of work on Port Kembla harbour from 1975 by Zhijia and Morrison (2001) showed a marked reduction in heavy metal contamination of the harbour water and its aquatic life as a result of controls on the discharge of industrial effluent.
2. Methods of sampling and analysis The method of sampling used was that described by Cawse and Peirson (1972). Air particulate was collected continuously on cellulose filters (Whatman 40 grade), of 6-cm diameter, held in a polypropylene duct at 1.5 m above ground level. Air was drawn through the filter by means of an electrically driven low suction
pump. The airflow rate, of about 10.5 m3 every 24 h, was measured exactly by a diaphragm flowmeter connected to the outflow manifold of the pump. Filters were changed half monthly and the two were analysed together as a single sample. The sampling equipment was mounted on a timber frame and polythene gloves and plastic forceps were used in the handling of the filter papers to avoid contamination. Instrumental neutron activation analysis (INAA), as described by Salmon (1975) and Salmon and Cawse (1990), and used routinely at the UK Atomic Energy Authority, Harwell Laboratory, was the preferred technique for the analysis of most elements in the 1978 study, supported by atomic absorption spectrometry for Cu, Ni and Cd, with X-ray fluorescence for Pb. Following the closure of the nuclear reactor at Harwell, the reactor at Imperial College, University of London, was used for INAA of the air filters from the 2001 –2002 study. The accuracy of analysis was validated by measurements on a standard reference material, SRM 1571, orchard leaves, from the National Bureau of Standards/National Institute of Standards and Technology. In addition, the application in the 1970s of INAA to multielement analysis of air particulate involved comparison with results from gamma-photon activation, atomic absorption and X-ray fluorescence methods (Cawse, 1976). During this comparison, the accuracy of INAA was established and results were within 5% of the 15 certified or indicated concentrations in the SRM 1571. The analysis of K, Ni, Cd and Pb was made by high-resolution inductively coupled plasma mass spectrometry, for which the Laboratory of the (UK) Government Chemist used gas works contaminated soil as reference material (LGC 6144). Samples of blank (unexposed) Whatman 40 filter papers were submitted to both laboratories and taken into account in the calculation of the results. Both the Government Chemist and Imperial College laboratories conform to UKAS methodology in respect of their quality control. Soil samples for the measurement of Cu were gently ground and passed through a 2-mm sieve of nylon mesh and aluminium frame; EDTA (0.02/L) was the extractant, as used by Purves and Mackenzie (1969), and determination was by atomic absorption spectrometry.
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3. Results and discussion 3.1. Comparison of the 1978 and 2001 – 2002 results and examination of ratios between elements Table 1 shows the average monthly concentrations at Port Kembla of 26 elements in the air for the year, May 2001 to April 2002, and separately, for the 3 months February, March and April 2002, and for the corresponding 3-month period in 1978, allowing a direct comparison between the average concentrations for these quarters after 24 years. The percentage
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uncertainty for analysis of this data is also included in Table 1. Table 1 also shows the atmospheric content of trace elements at two background sites remote from industry and exposed to a strong maritime influence: Cape Grim (latitude 40jS) at the northwest tip of Tasmania, shown on Fig. 1, a monitoring station of the Australian Nuclear Science and Technology Organisation (Cohen et al., 2000) and Collafirth (latitude 60jN) in the Shetland Isles, northern Scotland, a monitoring station of the UK Atomic Energy Authority (Cawse, 1977). Cape Grim, therefore, is in the path of prevail-
Table 1 Concentrations of elements in air at Port Kembla, NSW, Australia 2001 – 2002 and 1978 and comparison with background sites 1
2
3
4
5
6
Collafirth Shetland Isles 60jN
Cape Grim NW Tasmania 41jS
Percentage reduction in concentration:
Jan – Dec 1976
1992 – 1998 average
column 2 as a percentage of column 3
ng kg
121 36 25 116 – 8 24 18 11 32 28 21 22 26 14 51 8 18 – 4.7 14 4.7 9 3.3 – 2.4
1550 270 66 2200 760 300 0.011 1.4 0.39 2.7 52 0.062 <2 14 11 < 0.5 0.44 9.9 0.028 < 0.9 < 0.04 0.35 <1 0.004 < 0.008 14
Port Kembla 341/2jS
May 2001 – April 2002 ng kg
Na Mg Al Cl K Ca Sc V Cr Mn Fe Co Ni Cu Zn As Se Br Ag Cd In Sb I Au Hg Pb
1
Feb – Apr 2002
Feb – Apr 1978
aira; Percentage uncertainty of analysis in parentheses
2480 (2.2) 229 (8.0) 210 (3.3) 4397 (2.2) 131 (2.5) 725 (13) 0.046 (4.9) 1.7 (8.5) 1.3 (8.0) 7.3 (2.5) 389 (4.6) 0.22 (8.5) 34.4 (5.0) 200 (7.3) 157 (2.4) 13.5 (3.9) 4.0 (11) 11.1 (3.8) 0.4 (17) 1.8 (5.0) < 0.2 (4.7) 0.67 (5.0) 0.87 (13) 0.0015 (9.0) < 0.4 38.8 (5.0)
3109 259 147 5690 91 735 0.031 1.5 1.4 5.8 353 0.19 6.8 238 226 14.7 3.7 12.8 < 0.4 4.0 0.17 0.61 0.67 0.0013 < 0.4 47.3
2570 (6.1) 723 (10) 586 (4.2) 4900 (5.1) < 660 9200 (15) 0.13 (4.0) 8.4 (5.4) 13 (8.3) 18 (4.5) 1280 (5.5) 0.90 (7.0) 31 (5.3) 920 (11) 1600 (5.5) 29 (9.3) 49 (6.9) 71 (6.0) 15.6 (20) 86 (5.0) 1.2 (14) 12.9 (2.9) 7.4 (20) 0.04 (18) 0.62 2000 (5.4)
1
Results are quarterly or annual average concentrations for the period stated. a ng kg 1 1.226 = ng m 3, since 1 m3 air at 15 jC, 760 mm Hg (Standard Cubic Metre) = 1.226 kg.
aira
816 – 12.2 1223 32 31 – 0.82 0.08 0.57 3.3 0.2 0.33 1.1 0.98 – – 2.1 – – – – – – – 0.90
Na Mg Al Cl K Ca Sc V Cr Mn Fe Co Ni Cu Zn As Se Br Ag Cd In Sb I Au Hg Pb
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ing winds from the Southern Ocean, and the Shetland Isles from those of the North Atlantic. The figures for Collafirth are for the year 1976 and cover the same range of elements as for Port Kembla, the analysis being carried out in the same laboratory. The data for Cape Grim are averages for 1992 –1998 and are for 15 trace elements that include the heavy metals, Cr, Fe, Ni, Cu, Zn and Pb. Data shown in Figs. 3 and 6 also include a further background site: Bagauda, at latitude 11jN in the rural savanna of northern Nigeria (Beavington and Cawse, 1978). The land use of this region is peasant arable farming with manual labour only and transport to and from the small, scattered native villages is by donkeys (Beavington and Varley, 2000). The sampling and analytical methods for both Northern Hemisphere sites were the same as used for the Port Kembla study. It may be noted that although both Collafirth and Bagauda are very different in respect of their location and proportion of atmospheric elements derived from ocean and from land, their content of heavy metals is both low and similar (Fig. 3), owing to long distance dispersion of pollutants (Peirson et al., 1974). The contents of the
elements in the atmosphere at these background sites are only expected to show variation over the long term in response to climate change that affects rainfall, wind and temperature. The percentage differences for element concentrations at Port Kembla between 1978 and 2001– 2002 (Table 1, column 4) show a dramatic decrease in most elements associated with industrial pollution [decreases in Mg, Al, Ca (Table 1) could be attributed to improved controls in handling the ore]. Thus, in 2002, on average, there is less than 10% of the Se, Cd, Sb, I and Pb in the air than there was in 1978, less than 20% of theV, Cr, Zn and Br, less than 30% of the Cu and Fe and only about half of the As, compared with 1978. By comparison with Port Kembla, the purity of the air at Cape Grim is evident from the concentrations of Cr, Fe, Ni, Cu, Zn and Pb (Table 1) which are two orders of magnitude lower than at Port Kembla even since the modernisation of the smelter. Arimoto et al. (1989) found air of still greater purity at a site in the remote Pacific islands of Samoa (latitude 14jS) where concentrations of Cu and Pb were two orders of magnitude lower that at Cape Grim.
Fig. 3. Comparison of the atmospheric content of trace elements between Port Kembla and Cape Grim, NW Tasmania and two further background sites, Collafirth, Shetland Isles and Bagauda, West African savanna.
F. Beavington et al. / Science of the Total Environment 332 (2004) 39–49
The average concentration of atmospheric Pb reduces from 2000 ng kg 1 air during February to April 1978 to 47.3 ng kg 1 air over the same 3 months in 2002 and 39.8 ng kg 1 for the 2001 – 2002 year. These concentrations may also be compared with the annual average values of 0.9, 14 and 12 ng kg 1 air for rural locations at Cape Grim, Collafirth and Bagauda, respectively (Table 1 and Fig. 3). The two main sources of atmospheric Pb in Port Kembla in 1978 would have been emissions from the unmodernised smelter and lead from vehicle exhausts. The addition of lead to petrol in Australia ceased in 1988, except for older vehicles. Consequently, there was no need for the Br-enriched ethyl fluid additive which had a Pb/Br ratio of 2.8 (Lininger et al., 1966) to be used in petrol. The content of Br in the air fell sharply between 1978 and 2001 –2002. Table 2 shows that the Pb/Br ratio of 28 at Port Kembla in 1978 contrasts with 3.6 for 2001– 2002 (3.7 for February to April 2002). Exhaust emissions from leaded fuel, therefore, were a minor contributor relative to emissions of Pb from the smelter which had resulted in the former massive concentration of Pb in air particulate prior to the modernisation of the smelter. Measurements of Fe, Cu, Zn and Pb in the air near the smelter carried out by the laboratory of the smelter company, Port Kembla Copper, for the period April 2001 to March 2002 agree with the improvement in air
Table 2 Comparison of element ratios in rainwater, air and copper ore at Port Kembla Element Rainwater Air monthly Air average ratios mean of average for for Feb – 13 sites 2001 – 2002 April 1978 (Beavington, 1977)
Copper orea from
Cu/Zn Cu/Pb Cu/Cd Zn/Pb Zn/Cd Pb/Cd Pb/Br Fe/Al Fe/Pb Cl/Na
145 1000 290 308 – – 0.5 3.3 – – – – – – 321 11.3 340 300 – –
a
2.4 6.3 133 2.6 55 21 – – 12.5 –
1.3 5.0 111 3.9 87 22 3.6 1.9 9.8 1.8
0.6 0.5 10.7 0.8 18.6 23 28 2.2 0.64 1.9
Cobar N Parkes source source
Analysis of copper ore from the two main sources used by the smelter.
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quality as found in this study. Their sampling station, although in the same close vicinity to the smelter, was more exposed to it. A high-volume sampler was used that operated for short periods only, and the analytical method was different with only four elements, Fe, Cu, Zn and Pb, determined. Nevertheless, the concentrations of these elements in air, although higher by a factor of 1.2 to 3.0, are in similar order of concentration as recorded by the present study for the period 2001– 2002, whilst the element ratios in air particulate of Cu/Zn 1.8, Cu/Pb 7.4, Zn/Pb 4.0 and Fe/Pb 11.7 are comparable with those of Table 2. The ratios between certain heavy metals (Table 2) in air particulate for 2001– 2002 are close to those recorded from earlier analysis of rainwater and dry deposition, collected for 12 months at three locations within 610 m of the copper smelter (Beavington, 1977). Thus, the Cu/Zn, Cu/Cd and Pb/Cd ratios in air particulate and rainwater (i.e., the total deposition) are comparable for the historic 1978 data and recent measurements and thus indicate consistency in the spectrum of elements in air particulate emitted from the smelter. However, the relatively high content of both Cd and Pb in air in 1978 (Table 1) prior to the upgrading of the smelter would explain the lower ratios for Cu/Pb, Cu/Cd, Zn/Pb, Zn/Cd and Fe/ Pb than those recorded in 2001– 2002 (Table 2). The influence of the maritime aerosol is evident from the Cl/Na ratios in the range 1.7 to 1.9 for the year 2001– 2002, giving an average ratio of 1.8 which is the same as in seawater (Mason, 1966). A comparison of the ratios of metals in the copper ore from both its main sources, Cobar and North Parkes, with those for metals in the air during 2001 – 2002 (Table 2) show that copper is well removed from the ore. In addition, the relatively low ratio of 1.9 for Fe/Al in air for 2001– 2002, when compared with the much higher ratios in the ore samples of 11.3 (North Parkes) and 321 (Cobar), indicates little contribution of dust from ore handling. 3.2. Monthly variations in airborne trace elements Fig. 4 shows the monthly variations in the atmospheric content of elements of industrial origin for the year 2001– 2002, whilst Fig. 5 shows the less pronounced variations for these elements derived directly from terrestrial and marine sources. The smelter
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F. Beavington et al. / Science of the Total Environment 332 (2004) 39–49
Fig. 4. Monthly variation in the atmospheric content of elements mainly of industrial origin at Port Kembla (May 2001 to April 2002).
Fig. 5. Monthly variations in the atmospheric content of elements mainly of non-industrial origin at Port Kembla (May 2001 to April 2002).
F. Beavington et al. / Science of the Total Environment 332 (2004) 39–49
underwent annual maintenance during the second half of July and part of August 2001. This was followed by an apparent marked increase in smelting activity in September when there was a four to fivefold increase in many airborne metals over the July recordings. As would be expected, these variations did not occur in the atmospheric content of Na, Cl, Sc, V, Mn and Br (Fig. 5); these elements being mainly of non-industrial origin. There was a further sharp decline in January in the atmospheric content of the eleven metals shown in Fig. 4, but again, no change in the elements of Fig. 5. The smelter was not closed in this holiday month and although meteorological data (recorded at the University of Wollongong) showed there were days of high temperatures (31 – 35 jC maximum), there was no unusual weather. The obvious explanation for this improvement in air quality is a reduction in the amount of ore being smelted. During half of the study period, November 2001 to April 2002, when higher rainfall was recorded (742 mm) compared with 381 mm in the winter six months, onshore winds are more frequent and form 77% of all wind directions from December to February. In these 3 months, concentrations of Na and Cl in air were approximately 2.8 times greater than for the three corresponding winter months when offshore winds predominate limiting marine aerosol from sea spray. Br follows the same pattern. There were, however, no apparent seasonal variations for the elements derived from the land or for the heavy metals; the reduction of the latter being apparently due to reduced smelting. The supply and distribution of airborne contaminant metals in an industrial city are affected by a number of factors. Emissions from large smelters are supplemented by incineration, minor industrial sources, vehicles, domestic chimneys and bonfires, whilst distribution is affected by buildings and turbulence, especially in the immediate vicinity of the smelter chimney. Other sources, including industrial deposits and pockets of buried refuse, produce local variations in the soil content of heavy metals, as shown in the case of Cu (Fig. 2). In a different situation of a lowland rural area, Little and Martin (1972) showed, from a study of soil and vegetation up to some 15 km from the smelter at Avonmouth, UK, that the distribution of Zn, Pb and Cd was strongly influenced by prevailing winds.
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3.3. Enrichment factors and correlations The application of air particulate enrichment factors (EF) to demonstrate the influence of industrial activities on air quality was made in the 1970s when neutron activation of air filters could provide a comprehensive multielement analysis (Rahn, 1972; Peirson et al., 1974; Beavington and Cawse, 1978; Greenberg et al., 1978). The concentrations of elements recorded in air particulate are referred to a single element selected to represent a natural source material such as soil. Selection of a reference element to assess the contribution to the aerosol from soil or Earth’s crust may be made from Al, Ce, Sc, Si or Ti, and in the present study, Sc is the marker element.Thus, the EF for an element X=[X/Sc in aerosol]/[X/Sc in average soil (Bowen, 1966)]. The differences in enrichments of 17 elements in air particulate at Port Kembla are illustrated in Fig. 6 for high, intermediate and low EF groups and reveal order of magnitude variation, as expected from an industrial area. Further, a comparison with EF values recorded previously at a rural location in northern Nigeria (Beavington et al., 1978) indicates the extent of heavy metal pollution by industry at Port Kembla. The mechanism of enrichment in industrial atmospheres has been related to the high volatility of chalcophilic elements, e.g., Zn, Se, Cd and Pb, compared to those in the lithophilic group represented by Al, Sc, Mn and Fe. Consequently, the volatile metals arising from smelting and other combustion processes (e.g., incineration, use of fossil fuels, automobile exhaust) condense on the smaller size fraction of air particulate having relatively high surface area (Heindrycks, 1976). In respect of the atmospheric concentrations for 18 of the elements measured at Port Kembla (Table 1), correlations between pairs at P < 0.001 and P < 0.01 (Table 3) were predominant for Cu, Zn, As, Se and Pb, all with EF>100; none of these elements correlated with those from non-industrial origins, i.e., Na, Cl and Br from the marine aerosol, or Al and Sc brought into suspension from the land by wind, and hence without enrichment. At P < 0.05, correlations were found between 19 pairs of elements, of which 16 were for elements with industrial associations namely V, Co, Ni, Cd, Sb and Pb. The only correlation
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Fig. 6. Comparison of air particulate enrichment factors.
involving Fe in air, at either the 0.01% or the 0.1% level of significance, is with V (Table 3); there being no correlation of Fe with the heavy metals, the high enrichment of which (Fig. 6) is attributed to emissions from the smelter. This implies that the steelworks does
Table 3 Significance of correlations between pairs of elements in air particulate at Port Kembla 2001 – 2002 P < 0.001
P < 0.01
P < 0.05
r = 0.823
r = 0.710
r = 0.575
Pb – Cu Pb – Zn Pb – As
Pb – Se
Cu – As
Cu – Se Cu – Zn
Pb – Ni Pb – Sb Pb – Fe Pb – V Cu – V Cu – Cd Zn – Ni Zn – Se Zn – Sb As – Ni As – V Se – Co Ni – Sb Ni – Co Sb – Fe Sb – Co Fe – Mn
Zn – As
As – Se
Fe – V Sc – Al Na – Cl Na – Br Cl – Br
Na – Mn (negative) Cl – Mn (negative)
not have an appreciable influence on airborne metals at the sampling site.
4. Conclusion The investigations of the 1970s showed that the entire environment in Port Kembla was contaminated by heavy metals. It was also shown that except for Fe, the smelter was the dominant source of this contamination and that the concentration of metals in each of these parts of the environment, surface soil, herbage, vegetable gardens, rivulet and harbour water, rainwater and air, increased nearer to the smelter. The atmosphere is of dual concern since not only is it the principal medium for the contamination of the environment but it is breathed in daily and probably ingested by the people who live and work in the area. The improved environment emissions control installed in the smelter (and also in the steelworks) has resulted in a very substantial improvement in air quality, as far as metals are concerned, and this improvement shows what could be achieved if older smelters and other metal processing facilities were upgraded using modern technologies. Even so, the heavy metal content of the atmosphere of Port Kembla is still appreciably higher than that of the rural background of the West African savanna and the maritime background of Shetland, and in particular, that of the north west Tasmanian coast.
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Acknowledgements We thank Dr. R.T. Wheway of the University of Wollongong for assistance with the 1978 sampling programme, Dr. M.E. Frost for producing the correlation matrix, Mr. E.J. Beavington for the computer graphics, Ms. Roma Beamont for cartographic assistance, Mr G.E.L. McDougall for field assistance and the Soil Studies students of Wollongong University College who, in 1971, helped with the soil sampling programme. We also acknowledge the interest and assistance of the New South Wales Environment Protection Authority.
References Arimoto R, Duce RA, Ray BJ. Concentrations, sources and air – sea exchange of trace elements in the atmosphere over the Pacific Ocean. In: Riley JP, Chester R, editors. Chemical Oceanography, vol. 10. London: Academic Press; 1989. p. 107 – 47. Beavington F. Contamination of soil with zinc, copper, lead and cadmium in the Wollongong city area. Aust J Soil Res 1973; 11:27 – 31. Beavington F. Some aspects of contamination of herbage with copper, zinc and iron. Environ Pollut 1975a;8:65 – 71. Beavington F. Heavy metal contamination of vegetables and soil in domestic gardens around a smelting complex. Environ Pollut 1975b;9:211 – 7. Beavington F. Pollution by heavy metals of rivulet and harbour water in Wollongong. Search 1975c;9:390 – 1. Beavington F. Trace elements in rainwater and dry deposition around a smelting complex. Environ Pollut 1977;13:127 – 31. Beavington F, Cawse PA. Comparative studies of trace elements in air particulate in northern Nigeria. Sci Total Environ 1978;10: 239 – 44. Beavington F, Varley JA. Letter to the editor. Geogr J 2000;166: 282 – 3. Bowen HJM. Trace elements in biochemistry. New York: Academic Press; 1966. Cawse PA, editor. Inter-comparison of analysis of air filter deposits for trace elements. AERE Harwell Rep. R8191. London: HMSO; 1976. Cawse PA. A survey of the atmospheric trace elements in the UK: results for 1976. AERE Harwell Rep. R8869. London: HMSO; 1977. Cawse PA, Peirson DH. An analytical study of trace elements in the
49
atmospheric environment. AERE Harwell Rep. R7131. London: HMSO; 1972. Chiaradia M, Chenhall BE, Depers AM, Gulson BL, Jones BG. Identification of historic lead sources in roof dust and recent lake sediments from an industrialised area: indications from lead isotopes. Sci Total Environ 1997;205:107 – 28. Cohen DD, Garton D, Stelcer E. Multi-element methods for fine particle source apportionment at the global baseline station at Cape Grim, Tasmania. Nucl Instrum Methods Phys Res 2000; 161 – 163:775 – 9. Greenberg RR, Zoller WH, Gordon GE. The contribution of refuse incineration to urban aerosols. Proc. 4th Joint Conf. Sensing Environmental Pollutants. Washington (DC): American Chemical Society; 1978. p. 817 – 20. Heindrycks R. Comparison of the mass-size functions of the elements in the aerosols of Gent industrial district with data from other areas. Some physio-chemical implications. Atmos Environ 1976;10:65 – 71. Lininger RL, Duce RA, Winchester JW, Matson WR. Chlorine, bromine, iodine and lead in aerosols from Cambridge, Massachusetts. J Geophys Res 1966;71:2457 – 63. Little P, Martin MH. A survey of zinc, lead and cadmium in soil and natural vegetation around a smelting complex. Environ Pollut 1972;3:241 – 54. Mason B. Principles of geochemistry. 3rd ed. New York: Wiley; 1966. Payne M, Chenhall BE, Murray M, Jones BG. Spatial variation of sediment-bound zinc, lead, copper and rubidium in Lake Illawarra, a coastal lagoon in eastern Australia. J Coast Res 1997;13:1181 – 91. Peirson DH, Cawse PA, Cambray RS. Chemical uniformity of airborne particulate material, and a maritime effect. Nature (Lond.) 1974;251:675 – 9. Purves D, Mackenzie EJ. Trace element contamination of parkland in urban areas. J Soil Sci 1969;20:288 – 90. Rahn KA. Study of national air pollution by combustion, Progress Report, I.NW, University of Liege, Gent, Belgium; 1972. Roberts TM, Hutchinson TC, Paciga J, Chattopadhyay A, Jervis RE, Van Loon J, Parkinson DW. Lead contamination around secondary smelters: estimation of dispersal and accumulation by humans. Science 1974;186:1120 – 3. Salmon L. Instrumental neutron activation analysis in environmental studies of trace elements. AERE Harwell Rep., R7859. London: HMSO; 1975. Salmon L, Cawse PA. Instrumental neutron activation analysis. In: Smith KA, editor. Soil analysis: modern instrumental techniques, 2nd ed. New York: Marcel Dekker; 1990. p. 377 – 423. Zhijia HE, Morrison RJ. Changes in the marine environment of Port Kembla Harbour, NSW, Australia, 1975 – 1995: a review. Mar Pollut Bull 2001;42:193 – 201.