- Email: [email protected]
Polybrominated diphenyl ethers in indoor air during waste TV recycling process
Accepted Manuscript Title: Polybrominated Diphenyl Ethers in Indoor Air During Waste TV Recycling Process Author: Jie Guo Kuangfei Lin Jingjing Deng Xiaoxu Fu Zhenming Xu PII: DOI: Reference:
S0304-3894(14)00789-4 http://dx.doi.org/doi:10.1016/j.jhazmat.2014.09.044 HAZMAT 16292
To appear in:
Journal of Hazardous Materials
Received date: Revised date: Accepted date:
11-6-2014 4-8-2014 14-9-2014
Please cite this article as: J. Guo, K. Lin, J. Deng, X. Fu, Z. Xu, Polybrominated Diphenyl Ethers in Indoor Air During Waste TV Recycling Process, Journal of Hazardous Materials (2014), http://dx.doi.org/10.1016/j.jhazmat.2014.09.044 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.
Polybrominated Diphenyl Ethers in Indoor Air During Waste TV Recycling Process
a
ip t
Jie Guoa, Kuangfei Linb, Jingjing Dengb, Xiaoxu Fub, Zhenming Xua*
School of Environmental Science and Engineering, Shanghai Jiao Tong University,
State Environmental Protection Key Laboratory of Environmental Risk Assessment
us
b
cr
800 Dongchuan Road, Shanghai 200240, People’s Republic of China
and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237,
Corresponding author: Zhenming Xu
Fax: +86 21 54747495
te
Tel.: +86 21 54747495
d
E-mail: [email protected]
M
an
People's Republic of China
Ac ce p
School of Environmental Science and Engineering Shanghai Jiao Tong University
800 Dongchuan Road, Shanghai 200240, People’s Republic of China
Highlights: Air in the workshops was seriously contaminated by TV recycling activities. PBDEs profiles and levels varied with particulate matters and different workshops. 1
Page 1 of 41
Equilibrium between gas-particle partitioning was disrupted by recycling process. The highest occupational exposure concentrations occurred during heating
us
cr
ip t
process.
ABSTRACT:
an
Recycling process for waste TV sets mainly consists of dismantling, printed
M
wiring board (PWB) heating, PWB recycling, and plastic crushing in formal recycling plant. Polybrominated diphenyl ethers (PBDEs) contained in waste TV sets are
d
released to indoor air. Air samples at 4 different workshops were collected to measure
in indoor air were in the range of 6780-2280000 pg/m3.
Ac ce p
concentrations of
te
the PBDEs concentrations in both gaseous and particulate phases. The mean
The highest concentration in gaseous phase (291000 pg/m3) was detected in the PWB heating workshop. The
concentrations in PM2.5 and PM10 at the 4
workshops ranged in 6.8-6670 μg/g and 32.6-6790 μg/g, respectively. The gas-particle
partitioning of PBDEs was disrupted as PBDEs were continuously released during the recycling processes. Occupational exposure assessment showed that only the exposure concentration of BDE-47 (0.118 μg/kg/day) through inhalation in the PWB heating workshop for workers without facemask exceeded the reference dose (0.1 μg/kg/day), posing a health hazard to workers. All the results demonstrated that recycling of TV sets was an important source of PBDEs emission, and PBDEs emission pollution was 2
Page 2 of 41
related to the composition of TV sets, interior dust, and recycling process.
us
cr
ip t
Keywords: Particle pollution; recycling process; partition; risk assessment
1. Introduction
an
With the development of science and technology, the obsolete cathode ray tube television sets (CRT-TV) become an important category of waste electrical and
M
electronic equipment (WEEE). According to the data of Ministry of Commerce of China, 57.609 million units of waste household appliances were collected since the
te
d
enforcement of “Home Appliance Old for New Rebate Program” policy from June 1, 2009 to June 28, 2011 [1]. The volume of discarded TV sets is the largest portion of
Ac ce p
the WEEE categories, consisting of 81.53% of the total amount [2]. The composition of CRT-TV is complicated, containing CRT display, plastics, printed wiring board (PWB), and other electronic components. Generally, the process mainly includes TV dismantling, CRT processing, PWB recycling, and plastic crushing [3]. Hazardous substances contained in CRT-TV are released to indoor air during
recycling processes. High levels of heavy metals and brominated flame retardants (BFRs) were detected in WEEE materials [4], and in indoor dust collected from the workshops [5]. Polybrominated diphenyl ethers (PBDEs), a class of widely used BFRs, are commercially produced in three forms: penta-BDE, octa-BDE and 3
Page 3 of 41
deca-BDE. The penta-BDE and octa-BDE have been included in the Stockholm Convention on Persistent Organic Pollutants in May 2009 [6], leading to the elimination and restriction of commercial PBDEs products. Although the production
ip t
and application of penta-BDE has been banned, the release of penta-BDE from
cr
PBDEs-containing WEEE will be accelerated during recovery and recycling process.
us
The obsolete TV sets were produced decades ago, when PBDE mixture were widely used in TV part. A report showed that 25% of FR2-type PWB (FR-2 is an abbreviation
an
for Flame Resistant 2 of PWB, which is made of paper impregnated with phenol formaldehyde resin) in old appliances, such as CRT TV sets, radios, washing
M
machines, were treated with the mixture of penta-BDE [6]. So the recycling of waste CRT-TV is an important source of PBDEs release.
te
d
PBDEs is semivolatile organic compound, and it exists in both gaseous and particulate phases. Concentrations, profiles and gas-particle partitioning of PBDEs in
Ac ce p
air across China [7-9], especially in WEEE dismantling area, such as Guiyu [10,11], Guangdong Province, and Taizhou [12-15], Zhejiang Province, were investigated. Han et al. found that total concentration of
near the e-waste dismantling
area in Taizhou was 506 pg/m3 in summer [15]. Many studies have demonstrated that the informal recycling of WEEE can lead to seriously environmental pollution [11,16]. Particulate matter (PM) suspended in atmospheric environment can be described by size, including PM2.5 (defined as those particles with an aerodynamic diameter of 2.5 microns or less, also known as fine particles) and PM10 (defined as all particles equal 4
Page 4 of 41
to and less than 10 microns in aerodynamic diameter). Recently, the International Agency for Research on Cancer of the World Health Organization announced that PM, a major component of outdoor air pollution, was classified as carcinogenic to humans
ip t
[17]. Particle pollution in PM10 and PM2.5 during working time of recycling TV sets is
cr
attracting more attention due to the negative health effect of PM on workers. The
us
concentrations and health risk assessment of heavy metals (Cu, Cr, Cd, Ni, and Pb) adhered on PM2.5 and PM10 in and around the workshops were studied [3].
an
Twenty-two PBDE congeners in PM2.5 at Guiyu were measured, with the concentration of 16.6 ng/m3 [18]. So PM at the workshops during TV sets recycling
M
plays an important role in the exposure assessment of human health. The previous studies mainly focused on the status of PBDEs in outdoor air, and
te
d
indoor air [19,20], such as at home [21], cars [22], planes [23]. These observations have led to the hypothesis that release of contaminated air from indoor environments
Ac ce p
may be an important emission source of PBDEs to the outdoor environment [20]. However, research on PBDEs in the indoor air during different recycling processes of waste TV sets is rare. Therefore, the objective of this study is (1) to determine PBDE concentrations in gaseous phase and in PM2.5, PM10 and total suspended particles
(TSP) at different workshops; (2) to analyze PBDE partition between gaseous and particulate phases during working time; (3) to evaluate the occupational exposure of PBDE to workers’ health through inhalation.
2. Materials and methods 5
Page 5 of 41
2.1. Sampling location The study was conducted in a specialized factory for WEEE recycling located in Pudong District, Shanghai. Air samples were collected at different workshops
ip t
between June 2013 and July 2013 with daily capacity of about 2500 TV sets. The
cr
typical treatment process for CRT-TV recycling was shown in the Figure S1. A whole
us
waste CRT-TV was dismantled into different categories of materials in the TV dismantling workshop, then the dismantled materials, such as CRT, PWB, the back
an
casings of TV sets (also called housing plastic), wire and other electronic components (power cord, speaker, demagnetized coil), were treated, respectively. Because the
M
PBDEs mainly existed in PWB and housing plastic portion, we focused on the recycling process of PWB and housing plastic. Small electronic components
te
d
(capacitors, heat sinks, flyback transformers, etc.) affiliated on the surface of PWB were manually removed through melting solder using electric heating stove at 300 °C
Ac ce p
at an individual PWB heating workshop. The pretreated PWB were then recycled by mechanical method combining two-step crushing and electrostatic separating process at the PWB recycling workshop. Furthermore, the disassembled housing plastics of TV sets were transferred to a professional housing plastic crushing workshop by truck. The whole housing plastic was crushed to about 10 × 10 mm particles using a cutting machine. In addition, we selected a warehouse storing WEEE for a comparing site. So sampling locations included 4 workshops (TV dismantling, PWB heating, PWB recycling, and plastic crushing) and one warehouse (details were shown in Table S1). 2.2. Air and dust sampling 6
Page 6 of 41
Gas-phase air samples were collected by polyurethane foam (PUF) plugs (60 cm diameter × 51 mm length, SKC Inc. USA) using a high-volume sampler Model (220-280 L/min, TE-100, Tisch, USA). Concurrently, PM samples (PM2.5, PM10, and
ip t
TSP) were simultaneously collected on glass fiber filters (diameter=90 mm, pore
cr
size=0.1 µm, SKC Inc. USA) using three middle volume samplers (100 L/min, Lao
us
Ying 2030, Qingdao Laoshan electronic instrument factory Co. Ltd., China). The sampling duration for each sample was ~8 h during the working time. Prior to
an
sampling, filters were baked at 450 °C overnight. Then, they were allowed to cool to room temperature in a desiccator. PUF plugs were cleaned by Soxhlet extraction using
M
an acetone/hexane mixture (1:1) for 24 h.
Concentrations of PM2.5, PM10 and TSP were determined by weighting filters
te
d
before and after sampling. The weighted glass fibre filters were cut into chips using stainless scissors for PBDEs testing. Floor dust, surface dust from PWB and housing
Ac ce p
plastics were collected by the brushes which were cleaned by acetone/hexane solvent mixture (1:1 v/v). Then dust samples were added through 200-mesh screen. 2.3. Sample extraction, cleanup and analysis PUF plugs were extracted by Soxhlet extraction using an acetone/hexane solvent
mixture (1:1 v/v) for 24 h. Filters (PM2.5, PM10, and TSP) and dust samples were
separately extracted using microwave assisted extraction with 20 mL acetone/hexane solvent mixture (1:1 v/v). The extraction procedure was programmed for a temperature increase to 110 °C over a 10 min period which was maintained for 20 min. The dissolution and precipitation procedure was repeated three times. Prior to 7
Page 7 of 41
extraction, all the samples were spiked with
13
C12-labeled polychlorinated biphenyl
(PCB) congener (13C12-PCB-141 for tri- to nona-BDE) and
13
C12-BDE-209 (for
deca-BDE) as recovery standards. Samples were concentrated to a small volume and
ip t
transferred into hexane. Further clean up using multi layer silica gel column was
cr
carried out in a 12 cm × 10 mm i.d. glass column packed with, from bottom to top, 2
us
cm neutral alumina, 2 cm neutral silica, 2 cm alkalinized silica, 2 cm acidified silica, and 1 cm Na2SO4, and samples were eluted with dichloromethane/hexane mixture
an
(1:1 v/v).
The sample extracts were analyzed by an Agilent 7890A gas chromatograph
M
coupled with a 5975C mass spectrometer using negative chemical ionization (GC-NCI-MS) in the selected ion monitoring (SIM) mode. Helium (purity >
te
d
99.9995%) was used as the carrier gas at a flow rate of 1.5 mL/min and methane was used as a chemical ionization moderating gas at an ion source pressure of 82.7 kPa.
Ac ce p
Gas chromatographic separation was performed on a DB-5HT (15 m × 0.25 mm i.d., 0.25 μm film thickness, J&W Scientific, Folsom, CA, USA) capillary column, with temperature program increased from 110 °C (held for 1 min) to 320 °C at 8 °C/min (held for 3 min). The ionization temperature and interface temperature were set at 150 °C and 280 °C, respectively. The m/zs for tri- to nona-BDE congeners (79, 81),
BDE-209 (79, 81, 486, 488),
13
C12-PCB-141 (372, 374),
13
C12-PCB-208 (476, 478)
and 13C12-BDE-209 (414, 492) were selected. The 12 BDE congeners investigated in this study were BDE-28, -47, -100, -99, -154, -153, -183, -203, -208, -207, -206, and -209 (in order of retention times). 8
Page 8 of 41
Acetone, hexane, and dichloromethane (Sinopharm Chemical Reagent Co., Ltd, Shanghai, China) were of pesticide grade with purity > 98.0%. Standards of BDE congeners and 13C12-labeled PCB congeners were purchased from Accustandard (J&K
ip t
CHEMICA, New Haven, CT, USA).
cr
2.4. QA/QC
us
A procedure blank, a standard spiked blank, and triplicate samples were run with each batch of samples to ensure the accuracy and reproducibility. No detectable target
an
substances were found in blanks. The average recoveries for surrogate standard ranged from 85.2-105.4%. For each sample, PBDEs concentrations were the average
M
of 3 parallel testing results, and differences between duplicate samples were typically less than 30%. The limit of detection (signal/noise of 3) ranged from 0.2 to 2.5 ng/g
d
for tri- to nona-BDE and 50 ng/g for BDE-209 in PM and dust samples, and ranged
Ac ce p
te
from 0.083 to 0.16 pg/m3 for tri- to hepta-BDE in PUF samples.
3. Results and discussion
3.1. Concentrations of TSP, PM10 and PM2.5 (Figure 1)
The mass concentrations of PM2.5, PM10, and TSP in the warehouse and 4
workshops were shown in Figure 1. Mean concentrations at 4 workshops ranged in 103-230 μg/m3, 335-802 μg/m3, 442-1512 μg/m3 for PM2.5, PM10, and TSP, respectively.
According
to
the
Chinese
Ambient
Air
Quality
Standards
(GB3095-2012), the secondary standards for PM2.5, PM10, and TSP were 75, 150, and 9
Page 9 of 41
300 μg/m3, respectively. Obviously, the mass concentrations of PM2.5, PM10, and TSP at the 4 workshops were higher than the secondary standards, while PM concentrations in the warehouse was lower than the secondary standards, indicating
ip t
that ambient air in the workshops was seriously contaminated by TV recycling
cr
activities.
us
Particulate emissions to air within the plants were related to several factors, such as the amount of dust contained within TV sets, the recycling method and equipment
an
used, and the air circulation within the workshop. Most of the collected TV sets had been used and/or stored for several years, and significant amount of dust collected
M
outside as well as inside the TV sets. This dust was mobilized during the recycling process to the ambient air. The highest PM10 and TSP concentrations were obtained in
te
d
the TV dismantling workshop, with the mean values of 802 and 1512 μg/m3. TSP mass concentration at TV dismantling workshop in this study was lower than those in
Ac ce p
other e-waste dismantling halls in Sweden (3.3 mg/m3) [24] and in Guiyu (2.21 mg/m3) [25], China. However, the PM2.5/PM10 (0.27) in TV dismantling workshop was the lowest, indicating that suspended PM was mainly in the form of coarse particles emitted from dust collected outside as well as inside the TV sets. To our surprise, the highest value for PM2.5 occurred in PWB heating workshop (230 μg /m3).
This may be explained by the fact that the room temperature in PWB heating workshop was higher than other sampling sites due to the usage of electric stoves, and many working fans led to better air circulation, resulting in more fine particles captured by the air samplers. Furthermore, the recycling process in the PWB recycling 10
Page 10 of 41
workshop was equipped with cyclone dust extractor, and the air circulation in the plastic crushing workshop was effective as the workshop has open-sided structure. So
workshops were less than in the TV dismantling workshop.
cr
3.2. PBDE concentrations and congener compositions in air
ip t
the levels of particulate pollution in the PWB recycling and plastic crushing
us
(Table 1)
Total PBDE concentration combined from both gas with particulates varied
an
significantly among different workshops, as summarized in Table 1. Tri- to hepta-BDE were present in gaseous phase and PM10 while octa- to deca-BDEs were
M
detected only on the glass fibers indicating these higher brominated PBDE were associated primarily with the particulate phase. These results were in agreement with
te
d
the finding of previous study [22]. The concentrations of
at 4 workshops were in the order of plastic
Ac ce p
crushing > PWB heating > TV dismantling > PWB heating, with the range of 6780 -2280000 pg/m3. Total PBDE concentrations in the workshops were higher than in the warehouse (1310 pg/m3). Yu et al. [9] found that the concentration of particle-bound in the outside air in Pudong district, Shanghai (the location of recycling
plant in this paper) was 310 pg/m3. This indicated that human activities of recycling
TV sets would lead to air pollution of PBDEs. There were some reports on PBDEs in e-waste recycling plant, mainly focusing on e-waste dismantling. These published data are comparable to the results obtained at TV dismantling workshop. For example, it was reported that air concentrations of PBDEs in a dismantling hall in Sweden were 11
Page 11 of 41
0.35-2.1 ng/m3 for BDE-47, 0.54-5.5 ng/m3 for BDE-99, and 12-70 ng/m3 for BDE-209 [24]. Cahill et al. [26] obtained average concentration of total PBDEs in air samples collected inside the dismantling hall of an electronics recycling facility in
ip t
USA was 650000 pg/m3. The mean concentrations of PBDEs ranged from 21 to 2320
cr
ng/m3 at a WEEE recycling site in Finland [27]. However, the level of PBDEs in air at
us
e-waste recycling house in Vietnamese (620-720 pg/m3) [28] was lower than that in this study. The comparison of PBDE concentrations between recycling plant/house in
an
different regions indicated that the complicated mechanism of PBDE emission was related to several factors, such as the structure and size of the building, WEEE
M
category, throughput, recycling process and so on.
The highest concentration of PBDEs in gas was detected at PWB heating workshop,
te
d
and the value (291000 pg/m3) was approximately 2-4 orders of magnitude higher than those in other sampling sites. BDE-28, -47, and -99 were the most abundant
Ac ce p
congeners in the air, accounting for 28.6%, 60.5%, and 7.8% of the gaseous phase. Volatilization of a chemical and its presence in air is driven by the vapor pressure of the chemical, and vapor pressures of PBDE increase with decreasing molecular weight and degree of bromination [29]. The chamber studies [30,31] showed that the greater the vapor pressure, the more likely the BDE congener will volatilize from the plastic product into the air. In other words, the lower brominated BDE congeners with great vapor pressure were easier to migrate from the PWB matrix to the air during heating process under high temperature (about 200-300 °C) than under normal temperature (25-35 °C). 12
Page 12 of 41
concentration of 2280000 pg/m3 was
In the PM10 samples, the highest
obtained at plastic crushing workshop, and BDE-209 accounted for 95.2% of total PBDEs. More information on PBDEs in PM will be discussed in the forthcoming
ip t
section.
cr
(Figure 2)
us
It is interesting to compare the PBDE congener compositions in air (both gaseous and particulate phases) at different workshops as shown in Figure 2. Congener profile
an
of PBDEs at PWB heating workshop was obviously different from others. The ratio for BDE-47 and BDE-99 at PWB heating workshop was the highest (together
M
accounting for 70.4%), indicating the source of penta-BDE mixture existed during the PWB heating process. A high portion of BDE-209 (over 98%) was found in both TV
te
d
dismantling and plastic crushing workshops, which can be explained by the existence of deca-BDE contained in plastic surface dust and plastic materials as shown in Table
Ac ce p
2 [5]. The profile compositions of PBDEs in the warehouse and at PWB recycling workshop were similar, and BDE-209 was the main congener. The reasons for explaining the PBDEs air pollution were complicated, and the
proportion of PBDE congeners were intimately related to the PBDEs-containing products and dust collected on the surface of products. During the use phase of TV sets, the TV sets containing PBDEs mixture might off-gas PBDEs into the surrounding air, then transfer PBDE congener concentrations to interior dust [32]. Another chamber testing showed that when TV sets were placed into test chamber, and PBDEs were detected in air samples taken at the outlet of the chamber [30]. The 13
Page 13 of 41
concentrations and profiles of PBDEs were different in various TV materials and surface dust, leading to different PBDEs emission when waste TV sets were subjected
3.3. PBDEs concentrations and congener composition in PM
cr
(Table 2)
ip t
to dismantling, crushing, and disposal processes.
us
The concentrations of PBDEs per gram PM by weight were used to describe PBDEs in PM. The mean concentrations of penta-BDE, octa-BDE, deca-BDE, and
an
associated with PM2.5 and PM10 are listed in Table 2. PBDE concentrations in PWB, housing plastic, surface dust from PWB and housing plastic,
M
and floor dust in the warehouse and TV dismantling workshop investigated in our previous study were also cited in Table 2 [5]. The PBDE concentrations in PM2.5 and concentrations for PM2.5 and PM10
te
d
PM10 were varying, and the highest
were obtained in the plastic crushing workshop, followed by PWB heating and TV
Ac ce p
dismantling workshop. The amount of PBDEs sorbed to aerially suspended dust inside the workshops was decided not only by PM size, but also by formation and growth of particles, chemical and physical properties, sources of PM, or even partition between vapor and particle phases. For example, if the concentration of organic fraction in PM10 was lower than in PM2.5, the PBDEs in PM10 may lower than in
PM2.5. Further study on the relationship between PM size and the adsorbability of PBDEs is needed. (Figure 3) When TV sets were disassembled in the dismantling workshop, large quantities of 14
Page 14 of 41
dust were released from the TV waste, resulting in heavily particulate pollution as described in the above section. So PBDEs dispersed uniformly in both fine and course airborne particles, and PBDE profiles in PM2.5 and PM10 at TV dismantling workshop
ip t
showed the same characteristics (Figure 3a), in which BDE-209 was the dominant
cr
congener with a contribution of 99% ∑PBDEs. This result is explained that BDE-209
us
was easily affiliated to airborne particles, and generous amount of suspended particles in the TV dismantling workshop were captured by air samplers, leading to high
an
proportion of BDE-209.
The total concentrations of PBDEs in PM at PWB heating workshop were 3740
M
μg/g for PM2.5 and 1220 μg/g for PM10, and the ratios of BDE-209 were both less than 10%, indicating high percentages of lower molecular congeners in the indoor air in
te
d
the PWB heating workshop. It is noticeable that the penta-BDE in PM (accounting for 95.5% in PM2.5 and 88.5% in PM10) were quite abundant in the PWB heating
Ac ce p
workshop. As described, the PWB were produced decades ago, and commercial penta-BDE products prevailed at that time. The congener compositions in PM were consistent with the profile of the commercial penta-BDE products (DE-71 and 70-5DE) as shown in Figure 3b [33]. BDE-47, -99, and -100 were the most abundant congeners in the PWB heating workshop, accounting for 44.3%, 32.8%, and 11.3% of in PM2.5. Two heating stoves with 300 °C were working in the small PWB heating workshop with an area of about 24 square meters, and room temperature was about 30-35 °C. When PWB were suffered from heating process, the lower brominated PBDEs contained in PWB matrix tended to volatilize to the air 15
Page 15 of 41
microenvironment. Kemmlein et al. [31] found that the emission concentrations of BDE-28 and BDE-47 from a PWB increased significantly when raising the temperature from 23 °C to 60 °C in an emission test cell, proving the temperature was
ip t
a factor affecting the emission of PBDEs. As previously mentioned, large quantities of
cr
lower brominated PBDE were emitted from the PWB waste during the heating
us
process, and the indoor air were intensively filled with lower brominated PBDE both in gas and particulate phases. Comparing the PBDE congener compositions in PM at
an
PWB heating workshop with those in commercial penta-BDE mixture [33] and in PWB surface dust, it can obtain the result that lower brominated PBDEs were mainly
M
from PBDEs-containing PWB matrix, and BDE-209 mainly originated from PWB surface dust. The source of BDE-209 on PWB surface dust included: (1) volatilization
te
d
from deca-BDE mixture contained in housing plastics during the usage and product life of TV sets. Hirai et al., [30] calculated emission factors for BDE-209 of 2.8 ×
Ac ce p
10-6/tv/year, when the TV sets were placed in a chamber for 48-hour operation. (2) Dust on PWB surface collected from the surrounding environment when the TV set was used or stored.
The values of PBDEs concentrations in PM at the PWB recycling workshop were
significantly lower than those at PWB heating workshop as shown in Table 2. This result was related to the source of PM and the recycling process. PM in the PWB recycling workshop come from two sources: (1) surface dust in PWB, (2) dust leakage from the cracks appeared among the machines. Pieces of PWB were carried to the feed inlet of the crusher on a conveyer belt before the PWB underwent crushing and 16
Page 16 of 41
separating. The conveyer belt was shaking when conveying the PWB, which actuated the PWB’s surface dust to the air. The concentration and profile in PWB’s surface dust were shown in Table 2 and Figure 3b, respectively. After the PWB entered the crusher,
ip t
the closed mechanical recycling system did not generated severely particulate
cr
pollution, only dust leakage from the cracks appeared among the machines. Because
us
the machines were equipped with pulse-jet bag series dust filter and cyclone dust extractor, and the crushed particles were delivered by pipeline transportation system.
an
However, the pulse-jet bag series dust filter and the air outlet of the cyclone dust extractor, both of which were fixed outside the PWB recycling workshop, may cause
M
outdoor air pollution, which needed further study.
The concentration values of total PBDEs at plastic crushing workshop were 6670
te
d
μg/g in PM2.5 and 6790 μg/g in PM10, and BDE-209 was the main congener, accounting for 95 % of
. The higher brominated PBDE profiles in PM
Ac ce p
were consistent with the profiles of surface dust of housing plastic and the formulations of commercial deca-BDE products (102E and 82-0DE) as shown in Table 2 and Figure 3c [33].
The release mechanism of PBDEs was related to several factors, such as the
compositions of TV sets, interior dust, and the processing. PBDEs contained in TV sets may volatile toward the neighborhood in the form of gas or particles. PBDE emission from TV waste can be explained by the following two mechanisms: (1) Volatilization is one of the mechanisms of release from the PBDEs-containing product into the ambient air. PBDEs was added to the plastic and not covalently bonded with 17
Page 17 of 41
the plastic. It is possible for PBDEs emission from the PWB matrix during the volatilization process. Kemmlein et al. [31] determined PBDE emission by placing products treated with PBDEs into an enclosed chamber, passing an air stream over the
ip t
products, and systematically sampling the chamber air over the duration of the
cr
experiment. Obvious emission rate for BDE-47, -99, -100 were observed; (2) a second
us
possible mechanism of PBDEs transferring from TV sets to PM is through the abrasion of PBDE-treated materials [34]. The abrasion causes small polymers
an
particles that become incorporated as suspended PM in air. 3.4. Gas-particle partitioning of PBDEs
M
PBDEs are semivolatile organic compounds (SVOCs), and have the partition behaviors between the vapor and particle phases in air. Partitioning of atmospheric
d
SVOCs between gas and particle phases is also defined by the particle-gas partition
te
coefficient, KP (m3/μg) [35,36]:
Ac ce p
KP (CP / PM10) / CG
where CP and CG are the concentrations (pg/m3) of SVOCs in PM10 and gas phases,
respectively, and the unit of PM10 is μg/m3. Generally speaking, there are two mechanisms to explain the gas-particle partition
of SVOCs, including adsorption onto the aerosol surface and absorption into the aerosol organic matter. The two different mechanisms both lead to a linear relationship between logKP and logPL (sub-cooled liquid vapor pressure of the
analytes), which is expressed as [37]: +b 18
Page 18 of 41
where m and b are constants. The values of PL were temperature dependent, and ) which has been reported by
calculated from the equation (
Tittlemier et al. [36] for the PBDE congeners (BDE-28, -47, -99, -100, -153, -154, and
ip t
-183) studied in this study. Higher brominated PBDE (BDE-203, -206, -207, -208, and
cr
-209) mainly existed in the particulate phase, and they were not discussed in this
us
section.
The relative abundances of PBDEs in sampling sites are shown in Figure S2. In the
an
warehouse, more than half of BDE-28, -47, -99, -154, and -153 were found in the gas phase. For BDE-47, -100, -99, -154, -153, and -183 at TV dismantling and PWB
M
heating workshops, the BDE congeners were dominantly in the particulate phase, with particulate proportion over 68% and 57%, respectively. This result is expected dust
was
d
PBDEs-containing
constantly
released
to
airborne
te
because
microenvironment during dismantling and heating process, leading to a high PBDEs
Ac ce p
concentration in particulate phase. (Table 3)
Generally, slope (m) from plots of logKP vs. logPL can be considered as a
characterize value for evaluating the sorption processes (adsorption or absorption), and the value of m should be close to -1 at the ideal equilibrium. In reality, the m values derived from ambient air sampling often deviate from -1, and thus cannot be taken as indicative for nonequilibrium conditions [39,40]. However, it has been reported that the m values can be used to classify the type of sorption process: (1) m<-1, surface adsorption, (2) m>-0.6, absorption by the organic matter, and (3) -1< 19
Page 19 of 41
m<-0.6 for coexistence of both mechanisms [40]. The m and b values at different sampling sites were shown in Table 3, and the plots of logKP vs. logPL for the PBDEs at different sampling sites were shown in Figure S3. The m values ranged from -0.33
ip t
and -0.67, much larger than -1, indicating the partitioning equilibrium was dominated
cr
by coexistence of adsorption and absorption, or absorption process. The gas-particle
us
partitioning of PBDEs, which was related to the emission source of PBDEs and the recycling process, was disrupted as PBDEs in PM or gas were continuously released
an
during the working time, probably during TV dismantling, PWB heating, PWB crushing, and housing plastic crushing. For example, PBDEs source at TV
M
dismantling workshop originated from the dust interior TV sets (mostly in the particulate phase), while PBDEs source at PWB heating workshop originated from
te
d
PBDEs-containing PWB matrix and PWB surface dust (both in gaseous and particulate phases). The steepest slopes (m = -0.67) was obtained in the PWB heating
Ac ce p
workshop, and a high coefficient was noted between logKP and logPL (r2=0.84, P<0.0001). This may be due to the higher temperature caused by electric stove in the PWB heating workshop. Jin et al., [41] had obtained similar results that relatively higher equilibrium could be achieved at higher temperature. As a result, the gas-particle partitioning of PBDEs was complicated, and it was essentially controlled by source concentration, temperature, and physical-chemical properties of PBDE congeners, such as vapor pressure (VP), octanol air partition coefficient (Koa). Further study on mechanism of gas-particle partitioning of PBDEs at different workshops is needed. 20
Page 20 of 41
3.5. Health risk assessment of PBDEs exposure through inhalation Generally, inhalation of atmospheric air (both gas and PM10) is one of the primary means of human exposure to PBDEs [42]. Therefore, the inhalation exposure of total
ip t
PBDE concentration is calculated using the PBDE from PM10 and gas. In the case of
cr
WEEE recycling, workers at different recycling workshops inhaled pollutant air with
us
various levels of PBDEs contaminants. The average daily human intake of PBDEs via inhalation (assuming 100% absorption of intake) can be calculated using the
an
following equations [25]: :
M
is the daily occupational exposure via inhalation (ng of
Where
/person/day); CG, CP is the PBDE concentration (ng/m3) in the gaseous phase
d
and PM10, respectively. Work time (Tw), inhalation rate (Ir), and body weight (BW)
Ac ce p
According to total
te
were assumed to be 8 h, 3 m3/h [43], and 70 kg for each worker. concentrations at the 4 workshops (Table 1), it can
be concluded that the highest exposure site was plastic crushing workshop (782 ng/kg/day), followed by PWB heating (244 ng/kg/day) and TV dismantling (82.3 ng/kg/day). The lowest was 2.32 ng/kg/day at PWB recycling workshop. The 3M Particulate Respirator (Model 9032 KN90) was selected for the workers as
it provided good filtration performance with 90% efficiency against non-oil particulates. It is hypothesized that only 10% particulates and total gas were absorbed by air inhalation under the circumstance of wearing a facemask. In addition, the workers during working time were well protected by facemasks, goggles, dust cap, 21
Page 21 of 41
gloves, and clothing, and the dermal exposure was not evaluated in this study. So the average daily PBDEs intake of workers with facemask via inhalation can be
ip t
calculated using the following equations:
cr
(Table 4)
us
A comparison of BDE-congener exposure via the inhalation for different workshop workers is given in Table 4. BDE-47, -99, and -209 are the dominant congeners for
an
the inhalation exposure. The occupational inhalation exposure for BDE-47, -99, -153, and -209 were compared with the reference dose (RfD), as reported by U.S. EPA
M
Integrated Risk Information System. The draft RfD value was 0.1 μg/kg/day for BDE-47, -99, 0.2 μg/kg/day for BDE-153, and 7 μg/kg/day for BDE-209 [44].
te
d
Accordingly, the workers without facemask at PWB heating workshop had the exposure levels of 0.118, 0.0544, and 0.0151 μg/kg/day for BDE-47, BDE-99, and
Ac ce p
BDE-209, respectively. The exposure concentration of BDE-47 for workers without facemask (0.118 μg/kg/day) was higher than the draft RfD (0.1 μg/kg/day), posing a
health hazard to humans. However, when the workers wore the facemasks, the exposure risk decreased, and the exposure concentration of BDE-47 (0.0661 μg/kg/day) was lower than draft RfD. In addition, the exposure concentration of
BDE-99 (0.0544 μg/kg/day) for workers without facemask at PWB heating workshop was close to the draft RfD (0.1 μg/kg/day), showing potential health hazard to workers. From the viewpoint of health protection, wearing a facemask appeared to abrogate the adverse effects of air pollution at workshops, and had the potential to 22
Page 22 of 41
protect the workers from high concentrations of ambient PBDE pollution.
4. Conclusions
ip t
In summary, recycling of waste CRT-TV sets was an important source of PBDEs
cr
emission. BDE-209 in indoor air was mainly released from the TV dismantling and
us
plastic crushing process, while lower brominated PBDE originated from the PWB heating process. The gas-particle partitioning of PBDEs was disrupted by the constant
an
PBDEs emission during TV recycling process. The highest occupational exposure concentrations of BDE congeners occurred in the PWB heating workshop, posing a
d te
Acknowledgments
M
health hazard to workers.
This work was financially supported by the National Natural Science Foundation of
Ac ce p
China (21077071, 21307030). We would also appreciate the anonymous referees for their helpful comments on this paper.
Appendix A. Supplementary data Information for sampling sites (Table S1), recycling processes for waste CRT-TV
sets (Figure S1), relative distribution of PBDEs in air (Figure S2), and plots of logKP vs. logPL for PBDEs (Figure S3) are available.
References 23
Page 23 of 41
[1] MOFCOM (Ministry of Commerce of the People’s Republic of China), 2011. Available at: http://www.mofcom.gov.cn/aarticle/difang/henan/201106/20110607624819.html
ip t
[2] Q. Song, Z. Wang, J. Li, X. Zeng, Life cycle assessment of TV sets in China: A
cr
case study of the impacts of CRT monitors, Waste Manage. 32 (2012) 1926-1936.
us
[3] W. Fang, Y. Yang, Z. Xu, PM10 and PM2.5 and health risk assessment for heavy metals in a typical factory for cathode ray tube television recycling, Environ. Sci.
an
Technol. 47 (2013) 12469-12476.
[4] P.A. Wäger, M. Schluep, E. Müller, R. Gloor, RoHS regulated substances in
Technol. 46 (2012) 628-635.
M
mixed plastics from waste electrical and electronic equipment, Environ. Sci.
te
d
[5] J. Deng, J. Guo, X. Zhou, P. Zhou, X. Fu, W. Zhang, K. Lin, Hazardous substances in indoor dust emitted from waste TV recycling facility. Environ. Sci.
Ac ce p
Pollut. Res. 21 (2014) 7656-7667.
[6] UNEP, Stockholm Convention on Persistent Organic Pollutants (POPs). The 9 new POPs risk management evaluations 2005-2008 (POPRC1-POPRC4). Secretariat of the Stockholm Convention. United Nations Environment Programme. Switzerland, 2009.
[7] M. Yang, H. Jia, W. Ma, H. Qi, S. Cui, Y. Li, Levels, compositions, and gas-particle partitioning of polybrominated diphenyl ethers and dechlorane plus in air in a Chinese northeastern city, Atmos. Environ. 55 (2012) 73-79. [8] X. Qiu, T. Zhu, J. Hu, Polybrominated diphenyl ethers (PBDEs) and other flame 24
Page 24 of 41
retardants in the atmosphere and water from Taihu Lake, east China, Chemosphere 80 (2010) 1207-1212. [9] Z. Yu, R.E. Liao, H. Li, L. Mo, X. Zeng, G. Sheng, J. Fu, Particle-bound
cr
Shanghai, China, Environ. Pollut. 159 (2011) 2982-2988.
ip t
Dechlorane Plus and polybrominated diphenyl ethers in ambient air around
us
[10] M. Tian, S. Chen, J. Wang, X. Zheng, X. Luo, B. Mai, Brominated flame retardants in the atmosphere of e-waste and rural sites in southern China: Seasonal
an
variation, temperature dependence, and gas-particle partitioning, Environ. Sci. Technol. 45 (2011) 8819-8825.
M
[11] X. Bi, B.R.T. Simoneit, Z. Wang, X. Wang, G. Sheng, J. Fu, The major components of particles emitted during recycling of waste printed circuit boards in
4440-4445.
te
d
a typical e-waste workshop of south China, Atmos. Environ. 44 (2010)
Ac ce p
[12] Z. Gu, J. Feng, W. Han, M. Wu, J. Fu, G. Sheng, Characteristics of organic matter in PM2.5 from an e-waste dismantling area in Taizhou, China, Chemosphere 80 (2010) 800-806.
[13] Y. Li, G. Jiang, Y. Wang, P. Wang, Q. Zhang, Concentrations, profiles and gas-particle partitioning of PCDD/Fs, PCBs and PBDEs in the ambient air of an e-waste dismantling area, southeast China, Chin. Sci. Bull. 53 (2008) 521-528. (in Chinese) [14] T. Zhang, Y. Huang, S. Chen, A. Liu, P. Xu, N. Li, L. Qi, Y. Ren, Z. Zhou, B. Mai, PCDD/Fs, PBDD/Fs, and PBDEs in the air of an e-waste recycling area 25
Page 25 of 41
(Taizhou) in China: current levels, composition profiles, and potential cancer risks, J. Environ. Monitor. 14 (2012) 3156-3163. [15] W. Han, J. Feng, Z. Gu, D. Chen, M. Wu, J. Fu, Polybrominated diphenyl ethers
ip t
in the atmosphere of Taizhou, a major e-waste dismantling area in China, Bull.
cr
Environ. Contam. Toxicol. 83 (2009) 783-788.
us
[16] A.O.W. Leung, J. Zheng, C.K. Yu, W.K. Liu, C.K.C. Wong, Z. Cai, M.H. Wong, Polybrominated diphenyl ethers and polychlorinated dibenzo-p-dioxins and
an
dibenzofurans in surface dust at an e-waste processing site in southeast China, Environ. Sci. Technol. 45 (2011) 5775-5782.
M
[17] WHO., Outdoor air pollution a leading environmental cause of cancer deaths. International Agency for Research on Cancer, World Health Organization, 2013.
October 2013)
(accessed
20
te
d
http://www.iarc.fr/en/media-centre/iarcnews/pdf/pr221_E.pdf
Ac ce p
[18] W.J. Deng, J.S. Zheng, X.H. Bi, J.M. Fu, M.H. Wong, Distribution of PBDEs in air particles from an electronic waste recycling site compared with Guangzhou and Hong Kong, south China, Environ. Int. 33 (2007) 1063-1069.
[19] C.A. de Wit, J.A. Björklund, K. Thuresson, Tri-decabrominated diphenyl ethers and hexabromocyclododecane in indoor air and dust from Stockholm microenvironments 2: Indoor sources and human exposure, Environ. Int. 39 (2012) 141-147. [20] J.A. Björklund, K. Thuresson, A.P. Cousins, U. Sellström, G. Emenius, C.A. de Wit, Indoor air is a significant source of tri-decabrominated diphenyl ethers to 26
Page 26 of 41
outdoor air via ventilation systems, Environ. Sci. Technol. 46 (2012) 5876-5884. [21] D. Muenhor, S. Harrad, Within-room and within-building temporal and spatial variations in concentrations of polybrominated diphenyl ethers (PBDEs) in indoor
ip t
dust, Environ. Int. 47 (2012) 23-27.
cr
[22] M.A. Abdallah, S. Harrad, Modification and calibration of a passive air sampler
us
for monitoring vapor and particulate phase brominated flame retardants in indoor air: Application to car interiors, Environ. Sci. Technol. 44 (2010) 3059-3065.
an
[23] J.G. Allen, A.L. Sumner, M.G. Nishioka, J. Vallarino, D.J. Turner, H.K. Saltman, J.D. Spengler, Air concentrations of PBDEs on in-flight airplanes and assessment
M
of flight crew inhalation exposure, J. Expo. Sci. Environ. Epid. 23 (2012) 337-342.
Å. Bergman, C. Östman,.
te
d
[24] A. Sjödin, H.A. Carlsson, K. Thuresson, S. Sjölin,
Flame retardants in indoor air at an electronics recycling plant and at other work
Ac ce p
environments, Environ. Sci. Technol. 35 (2001) 448-454.
[25] T. An, D. Zhang, G. Li, B. Mai, J. Fu, On-site and off-site atmospheric PBDEs in an electronic dismantling workshop in south China: Gas-particle partitioning and human exposure assessment, Environ. Pollut. 159 (2011) 3529-3535.
[26] T.M. Cahill, D. Groskova, M.J. Charles, J.R. Sanborn, M.S. Denison, L. Baker, Atmospheric concentrations of polybrominated diphenyl ethers at near-source sites, Environ. Sci. Technol. 41 (2007) 6370-6377. [27] C. Rosenberg, M. Hämeilä, J. Tornaeus, K. Säkkinen, K. Puttonen, A. Korpi, M. Kiilunen, M. Linnainmaa, A. Hesso, Exposure to flame retardants in electronics 27
Page 27 of 41
recycling sites, Ann. Occup. Hyg. 55 (2011) 658-665. [28] N.M. Tue, S. Takahashi, G. Suzuki, T. Isobe, P.H. Viet, Y. Kobara, N. Seike, G. Zhang, A. Sudaryanto, S. Tanabe, Contamination of indoor dust and air by
ip t
polychlorinated biphenyls and brominated flame retardants and relevance of
cr
non-dietary exposure in Vietnamese informal e-waste recycling sites, Environ. Int.
us
51 (2013) 160-167.
[29] USEPA, An exposure assessment of polybrominated diphenyl ethers,
Technical
Information
an
(EPA/600/R-08/086F); Washington DC, 2010. Available from the National Service,
VA,
and
online
at
M
http://www.epa.gov/ncea.
Springfield,
[30] Y. Hirai, S. Sakai, K. Sato, K. Hayakawa, K. Shiozaki, Emission of brominated
te
d
flame retardants from TV sets, Organohalogen Compd. 68 (2006) 1772-1775. [31] S. Kemmlein, O. Hahn, O. Jann, Emissions of organophosphate and brominated
Ac ce p
flame retardants from selected consumer products and building materials, Atmos. Environ. 37 (2003) 5485-5493.
[32] H. Takigami, G. Suzuki, Y. Hirai, S. Sakai, Transfer of brominated flame retardants from components into dust inside television cabinets, Chemosphere 73 (2008) 161-169.
[33] M.J. La Guardia, R.C. Hale, E. Harvey, Detailed polybrominated diphenyl ether (PBDE) congener composition of the widely used Penta-, Octa-, and Deca-PBDE technical flame-retardant mixtures, Environ. Sci. Technol. 40 (2006) 6247-6254. [34] T.F. Webster, S. Harrad, J.R. Millette, R.D. Holbrook, J.M. Davis, H.M. 28
Page 28 of 41
Stapleton, J.G. Allen, M.D. McClean, C. Ibarra, M.A. Abdallah, A. Covaci, Identifying transfer mechanisms and sources of decabromodiphenyl ether (BDE 209) in indoor environments using environmental forensic microscopy, Environ.
ip t
Sci. Technol. 43 (2009) 3067-3072.
cr
[35] T. Harner, T.F. Bidleman, Octanol-air partition coefficient for describing
us
particle/gas partitioning of aromatic compounds in urban air, Environ. Sci. Technol. 32 (1998) 1494-1502.
an
[36] M. Yang, H. Qi, H. Jia, N. Ren, Y. Ding, W. Ma, L. Liu, H. Hung, E. Sverko, Y. Li, Polybrominated diphenyl ethers in air across China: levels, compositions,
M
and gas-particle partitioning, Environ. Sci. Technol. 47 (2013) 8978-8984. [37] D. Chen, X. Bi, J. Zhao, L. Chen, J. Tan, B. Mai, G. Sheng, J. Fu, M.H. Wong,
te
d
Pollution characterization and diurnal variation of PBDEs in the atmosphere of an e-waste dismantling region, Environ. Pollut. 157 (2009) 1051-1057.
Ac ce p
[38] S.A. Tittlemier, T. Halldorson, G.A. Stern, G.T. Tomy, Vapor pressures, aqueous solubilities, and Henry's law constants of some brominated flame retardants, Environ. Toxicol. Chem. 21 (2002) 1804-1810.
[39] J.F. Pankow, T.F. Bidleman, Interdependence of the slopes and intercepts from log-log correlations of measured gas-particle partitioning and vapor pressure-I. Theory and analysis of available data, Atmos. Environ. 26A (1992) 1071-1080. [40] K.U. Goss, R.P. Schwarzenbach, Gas/solid and gas/liquid partitioning of organic compounds: Critical evaluation of the interpretation of equilibrium constants, Environ. Sci. Technol. 32 (1998) 2025-2032. 29
Page 29 of 41
[41] J. Jin, Y. Wang, W. Liu, C. Yang, J. Hu, J. Cui, Polybrominated diphenyl ethers in atmosphere and soil of a production area in China: Levels and partitioning, J. Environ. Sci. (China), 23 (2011) 427-433.
ip t
[42] S. Harrad, S. Hazrati, C. Ibarra, Concentrations of polychlorinated biphenyls in
cr
indoor air and polybrominated diphenyl ethers in indoor air and dust in
us
Birmingham, United Kingdom: Implications for human exposure, Environ. Sci. Technol. 40 (2006) 4633-4638.
an
[43] USEPA, Exposure Factors Handbook: 2011 Edition. National Center for Environmental Assessment, (EPA/600/R-09/052F); Washington DC, 2011.
M
Available from the National Technical Information Service, Springfield, VA, and online at http://www.epa.gov/ncea/efh.
te
d
[44] USEPA, Integrated Risk Information System: 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) (CASRN 5436-43-1), http://www.epa.gov/iris/subst/1010.htm (accessed 2013);
Ac ce p
October
Integrated
2,2',4,4',5-Pentabromodiphenyl
Risk
ether
(BDE-99)
Information (CASRN
System: 60348-60-9),
http://www.epa.gov/iris/subst/1008.htm (accessed October 2013); Integrated Risk
Information System: 2,2',4,4',5,5'-Hexabromodiphenyl ether (BDE-153) (CASRN 68631-49-2), http://www.epa.gov/iris/subst/1009.htm (accessed October 2013);
Integrated Risk Information System: 2,2',3,3',4,4',5,5',6,6'-Decabromodiphenyl ether (BDE-209) (CASRN 1163-19-5), http://www.epa.gov/iris/subst/0035.htm (accessed 17 October 2013).
30
Page 30 of 41
Table and Figure legends
ip t
Table 1. Mean Concentrations (sd) of PBDEs in the Air (PM10 and gas phase) of Different Sampling Sites (pg/m3)
cr
Table 2. PBDEs Concentrations in PM2.5 and PM10 at Different Sampling Sites (μg/g) Table 3. Linear Relationship between logKP and logPL of PBDEs at Different
us
Sampling Sites
an
Table 4. Inhalation Exposure of PBDE Congeners -47, -99, -153, and -209 for
M
Workers with or without Facemask (μg/kg/day)
Figure 1. Mean concentrations of PM2.5, PM10 and TSP at different sampling sites.
te
sampling sites.
d
Figure 2. Congener contributions in air (both gas phase and PM10) at different
Ac ce p
Figure 3. Congener contributions in PM, dust, and commercial mixtures.
31
Page 31 of 41
ip t cr
warehouse
TV dismantling
us
Table 1. Mean Concentrations of PBDEs in the Air (PM10 and gas phase) of Different Sampling Sites (pg/m3) PWB heating
PWB recycling
Plastic crushing
gas
PM10
gas
PM10
gas
PM10
gas
PM10
gas
BDE-28
1.19
32.7
66.7
898
16200
83100
26.0
117
137
983
BDE-47
9.91
37.4
458
322
167000
176000
251
318
2990
3190
BDE-100
0.72
0.57
117
17.4
51100
8660
10.9
9.06
136
117
BDE-99
11.8
7.63
882
111
136000
22600
314
92.5
2180
22.0
BDE-154
0.43
0.86
77.7
7.17
4340
184
3.50
4.83
60.8
38.4
BDE-153
1.54
1.68
364
2.72
1610
616
20.0
15.7
771
145
BDE-183
4.70
0.48
273
0.78
950
25.3
4.64
0.83
4800
90.3
BDE-203
3.97
-
4.37
-
24.3
-
15.2
-
3370
-
BDE-208
17.8
-
1080
-
538
-
36.3
-
12000
-
BDE-207
5.18
-
352
-
61. 5
-
23.3
-
12100
-
BDE-206
50.0
-
3230
-
577
-
223
-
71900
-
BDE-209
1120
-
232000
-
44000
-
5290
-
2170000
-
239000
-
422000
-
6220
-
2280000
-
ed
ce pt
Ac
1230
81.2
Total
1310
M an
PM10
1360
291000
240000
713000
558 6780
4580 2280000
32
Page 32 of 41
ip t cr us
Table 2. PBDEs Concentrations in PM2.5 and PM10 at Different Sampling Sites (μg/g) TV dismantling
PM10
floor dustd
PM2.5
PM10
floor dustd
penta-BDEa
0.17
0.33
1.51
3.81
2.47
1.50
octa-BDEb
0.19
0.11
2.64
0.47
0.35
1.38
deca-BDEc
8.99
16.4
180
472
320
9.35
16.8
184
476
323
Plastic crushing
PM10
PM2.5
PM10
PWBd
PWB dustd
PM2.5
PM10
plasticd
plastic dustd
3570
1080
4.98
0.27
6030
20.0
40.5
18.7
1.45
6.61
4.48
2.81
2.94
0.093
6.02
0.32
33.4
24.4
4.11
2.91
100
168
138
8.91
32.2
5.35
52.6
6600
6750
6920
102
103
3740
1220
16.8
32.6
6044
72.9
6670
6790
6920
112
ce pt
penta-BDE(28, 47, 99, 100, 153, 154), bocta-BDE(183, 203), cdeca-BDE (206, 207, 208, 209) d data cited from Reference [5]
Ac
a
PWB recycling
PM2.5
ed
PM2.5
PWB heating
M an
warehouse
33
Page 33 of 41
ip t cr us
M an
Table 3. Linear Relationship between logKP and logPL of PBDEs at Different Sampling Sites
-0.55
TV dismantling
-0.33
PWB heating
-0.67
PWB recycling
-0.33
Plastic crushing
-0.54
b
r2
P
-4.48
0.58
<0.0001
-4.65
0.25
0.020
-4.54
0.84
<0.0001
-3.62
0.39
2.52E-3
-4.24
0.34
0.046
Ac
ce pt
warehouse
ed
m
34
Page 34 of 41
ip t cr us
Table 4. Inhalation Exposure of PBDE Congeners -47, -99, -153, and -209 for Workers with or without Facemask (μg/kg/day) without facemask TV dismantling
PWB heating
M an
draft RfD
with facemask
PWB recycling
Plastic crushing
TV dismantling
PWB heating
PWB recycling
Plastic crushing
1.95E-04
2.12E-03
1.26E-04
6.61E-02
1.18E-04
1.20E-03
1.39E-04
7.55E-04
6.83E-05
1.24E-02
4.25E-05
8.23E-05
0.1
2.67E-04
0.118
BDE-99
0.1
3.40E-04
5.44E-02
BDE-153
0.2
1.26E-04
7.63E-04
1.22E-05
3.14E-04
1.34E-05
2.66E-04
6.07E-06
7.61E-05
BDE-209
7
7.95E-02
1.51E-02
1.81E-03
7.44E-01
7.95E-03
1.51E-03
1.81E-04
7.44E-02
Ac
ce pt
ed
BDE-47
35
Page 35 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Figure 1
Page 36 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Figure 2
Page 37 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Figure 3a
Page 38 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Figure 3b
Page 39 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Figure 3c
Page 40 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Graphical Abstract (for review)
Page 41 of 41
S0304-3894(14)00789-4 http://dx.doi.org/doi:10.1016/j.jhazmat.2014.09.044 HAZMAT 16292
To appear in:
Journal of Hazardous Materials
Received date: Revised date: Accepted date:
11-6-2014 4-8-2014 14-9-2014
Please cite this article as: J. Guo, K. Lin, J. Deng, X. Fu, Z. Xu, Polybrominated Diphenyl Ethers in Indoor Air During Waste TV Recycling Process, Journal of Hazardous Materials (2014), http://dx.doi.org/10.1016/j.jhazmat.2014.09.044 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.
Polybrominated Diphenyl Ethers in Indoor Air During Waste TV Recycling Process
a
ip t
Jie Guoa, Kuangfei Linb, Jingjing Dengb, Xiaoxu Fub, Zhenming Xua*
School of Environmental Science and Engineering, Shanghai Jiao Tong University,
State Environmental Protection Key Laboratory of Environmental Risk Assessment
us
b
cr
800 Dongchuan Road, Shanghai 200240, People’s Republic of China
and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237,
Corresponding author: Zhenming Xu
Fax: +86 21 54747495
te
Tel.: +86 21 54747495
d
E-mail: [email protected]
M
an
People's Republic of China
Ac ce p
School of Environmental Science and Engineering Shanghai Jiao Tong University
800 Dongchuan Road, Shanghai 200240, People’s Republic of China
Highlights: Air in the workshops was seriously contaminated by TV recycling activities. PBDEs profiles and levels varied with particulate matters and different workshops. 1
Page 1 of 41
Equilibrium between gas-particle partitioning was disrupted by recycling process. The highest occupational exposure concentrations occurred during heating
us
cr
ip t
process.
ABSTRACT:
an
Recycling process for waste TV sets mainly consists of dismantling, printed
M
wiring board (PWB) heating, PWB recycling, and plastic crushing in formal recycling plant. Polybrominated diphenyl ethers (PBDEs) contained in waste TV sets are
d
released to indoor air. Air samples at 4 different workshops were collected to measure
in indoor air were in the range of 6780-2280000 pg/m3.
Ac ce p
concentrations of
te
the PBDEs concentrations in both gaseous and particulate phases. The mean
The highest concentration in gaseous phase (291000 pg/m3) was detected in the PWB heating workshop. The
concentrations in PM2.5 and PM10 at the 4
workshops ranged in 6.8-6670 μg/g and 32.6-6790 μg/g, respectively. The gas-particle
partitioning of PBDEs was disrupted as PBDEs were continuously released during the recycling processes. Occupational exposure assessment showed that only the exposure concentration of BDE-47 (0.118 μg/kg/day) through inhalation in the PWB heating workshop for workers without facemask exceeded the reference dose (0.1 μg/kg/day), posing a health hazard to workers. All the results demonstrated that recycling of TV sets was an important source of PBDEs emission, and PBDEs emission pollution was 2
Page 2 of 41
related to the composition of TV sets, interior dust, and recycling process.
us
cr
ip t
Keywords: Particle pollution; recycling process; partition; risk assessment
1. Introduction
an
With the development of science and technology, the obsolete cathode ray tube television sets (CRT-TV) become an important category of waste electrical and
M
electronic equipment (WEEE). According to the data of Ministry of Commerce of China, 57.609 million units of waste household appliances were collected since the
te
d
enforcement of “Home Appliance Old for New Rebate Program” policy from June 1, 2009 to June 28, 2011 [1]. The volume of discarded TV sets is the largest portion of
Ac ce p
the WEEE categories, consisting of 81.53% of the total amount [2]. The composition of CRT-TV is complicated, containing CRT display, plastics, printed wiring board (PWB), and other electronic components. Generally, the process mainly includes TV dismantling, CRT processing, PWB recycling, and plastic crushing [3]. Hazardous substances contained in CRT-TV are released to indoor air during
recycling processes. High levels of heavy metals and brominated flame retardants (BFRs) were detected in WEEE materials [4], and in indoor dust collected from the workshops [5]. Polybrominated diphenyl ethers (PBDEs), a class of widely used BFRs, are commercially produced in three forms: penta-BDE, octa-BDE and 3
Page 3 of 41
deca-BDE. The penta-BDE and octa-BDE have been included in the Stockholm Convention on Persistent Organic Pollutants in May 2009 [6], leading to the elimination and restriction of commercial PBDEs products. Although the production
ip t
and application of penta-BDE has been banned, the release of penta-BDE from
cr
PBDEs-containing WEEE will be accelerated during recovery and recycling process.
us
The obsolete TV sets were produced decades ago, when PBDE mixture were widely used in TV part. A report showed that 25% of FR2-type PWB (FR-2 is an abbreviation
an
for Flame Resistant 2 of PWB, which is made of paper impregnated with phenol formaldehyde resin) in old appliances, such as CRT TV sets, radios, washing
M
machines, were treated with the mixture of penta-BDE [6]. So the recycling of waste CRT-TV is an important source of PBDEs release.
te
d
PBDEs is semivolatile organic compound, and it exists in both gaseous and particulate phases. Concentrations, profiles and gas-particle partitioning of PBDEs in
Ac ce p
air across China [7-9], especially in WEEE dismantling area, such as Guiyu [10,11], Guangdong Province, and Taizhou [12-15], Zhejiang Province, were investigated. Han et al. found that total concentration of
near the e-waste dismantling
area in Taizhou was 506 pg/m3 in summer [15]. Many studies have demonstrated that the informal recycling of WEEE can lead to seriously environmental pollution [11,16]. Particulate matter (PM) suspended in atmospheric environment can be described by size, including PM2.5 (defined as those particles with an aerodynamic diameter of 2.5 microns or less, also known as fine particles) and PM10 (defined as all particles equal 4
Page 4 of 41
to and less than 10 microns in aerodynamic diameter). Recently, the International Agency for Research on Cancer of the World Health Organization announced that PM, a major component of outdoor air pollution, was classified as carcinogenic to humans
ip t
[17]. Particle pollution in PM10 and PM2.5 during working time of recycling TV sets is
cr
attracting more attention due to the negative health effect of PM on workers. The
us
concentrations and health risk assessment of heavy metals (Cu, Cr, Cd, Ni, and Pb) adhered on PM2.5 and PM10 in and around the workshops were studied [3].
an
Twenty-two PBDE congeners in PM2.5 at Guiyu were measured, with the concentration of 16.6 ng/m3 [18]. So PM at the workshops during TV sets recycling
M
plays an important role in the exposure assessment of human health. The previous studies mainly focused on the status of PBDEs in outdoor air, and
te
d
indoor air [19,20], such as at home [21], cars [22], planes [23]. These observations have led to the hypothesis that release of contaminated air from indoor environments
Ac ce p
may be an important emission source of PBDEs to the outdoor environment [20]. However, research on PBDEs in the indoor air during different recycling processes of waste TV sets is rare. Therefore, the objective of this study is (1) to determine PBDE concentrations in gaseous phase and in PM2.5, PM10 and total suspended particles
(TSP) at different workshops; (2) to analyze PBDE partition between gaseous and particulate phases during working time; (3) to evaluate the occupational exposure of PBDE to workers’ health through inhalation.
2. Materials and methods 5
Page 5 of 41
2.1. Sampling location The study was conducted in a specialized factory for WEEE recycling located in Pudong District, Shanghai. Air samples were collected at different workshops
ip t
between June 2013 and July 2013 with daily capacity of about 2500 TV sets. The
cr
typical treatment process for CRT-TV recycling was shown in the Figure S1. A whole
us
waste CRT-TV was dismantled into different categories of materials in the TV dismantling workshop, then the dismantled materials, such as CRT, PWB, the back
an
casings of TV sets (also called housing plastic), wire and other electronic components (power cord, speaker, demagnetized coil), were treated, respectively. Because the
M
PBDEs mainly existed in PWB and housing plastic portion, we focused on the recycling process of PWB and housing plastic. Small electronic components
te
d
(capacitors, heat sinks, flyback transformers, etc.) affiliated on the surface of PWB were manually removed through melting solder using electric heating stove at 300 °C
Ac ce p
at an individual PWB heating workshop. The pretreated PWB were then recycled by mechanical method combining two-step crushing and electrostatic separating process at the PWB recycling workshop. Furthermore, the disassembled housing plastics of TV sets were transferred to a professional housing plastic crushing workshop by truck. The whole housing plastic was crushed to about 10 × 10 mm particles using a cutting machine. In addition, we selected a warehouse storing WEEE for a comparing site. So sampling locations included 4 workshops (TV dismantling, PWB heating, PWB recycling, and plastic crushing) and one warehouse (details were shown in Table S1). 2.2. Air and dust sampling 6
Page 6 of 41
Gas-phase air samples were collected by polyurethane foam (PUF) plugs (60 cm diameter × 51 mm length, SKC Inc. USA) using a high-volume sampler Model (220-280 L/min, TE-100, Tisch, USA). Concurrently, PM samples (PM2.5, PM10, and
ip t
TSP) were simultaneously collected on glass fiber filters (diameter=90 mm, pore
cr
size=0.1 µm, SKC Inc. USA) using three middle volume samplers (100 L/min, Lao
us
Ying 2030, Qingdao Laoshan electronic instrument factory Co. Ltd., China). The sampling duration for each sample was ~8 h during the working time. Prior to
an
sampling, filters were baked at 450 °C overnight. Then, they were allowed to cool to room temperature in a desiccator. PUF plugs were cleaned by Soxhlet extraction using
M
an acetone/hexane mixture (1:1) for 24 h.
Concentrations of PM2.5, PM10 and TSP were determined by weighting filters
te
d
before and after sampling. The weighted glass fibre filters were cut into chips using stainless scissors for PBDEs testing. Floor dust, surface dust from PWB and housing
Ac ce p
plastics were collected by the brushes which were cleaned by acetone/hexane solvent mixture (1:1 v/v). Then dust samples were added through 200-mesh screen. 2.3. Sample extraction, cleanup and analysis PUF plugs were extracted by Soxhlet extraction using an acetone/hexane solvent
mixture (1:1 v/v) for 24 h. Filters (PM2.5, PM10, and TSP) and dust samples were
separately extracted using microwave assisted extraction with 20 mL acetone/hexane solvent mixture (1:1 v/v). The extraction procedure was programmed for a temperature increase to 110 °C over a 10 min period which was maintained for 20 min. The dissolution and precipitation procedure was repeated three times. Prior to 7
Page 7 of 41
extraction, all the samples were spiked with
13
C12-labeled polychlorinated biphenyl
(PCB) congener (13C12-PCB-141 for tri- to nona-BDE) and
13
C12-BDE-209 (for
deca-BDE) as recovery standards. Samples were concentrated to a small volume and
ip t
transferred into hexane. Further clean up using multi layer silica gel column was
cr
carried out in a 12 cm × 10 mm i.d. glass column packed with, from bottom to top, 2
us
cm neutral alumina, 2 cm neutral silica, 2 cm alkalinized silica, 2 cm acidified silica, and 1 cm Na2SO4, and samples were eluted with dichloromethane/hexane mixture
an
(1:1 v/v).
The sample extracts were analyzed by an Agilent 7890A gas chromatograph
M
coupled with a 5975C mass spectrometer using negative chemical ionization (GC-NCI-MS) in the selected ion monitoring (SIM) mode. Helium (purity >
te
d
99.9995%) was used as the carrier gas at a flow rate of 1.5 mL/min and methane was used as a chemical ionization moderating gas at an ion source pressure of 82.7 kPa.
Ac ce p
Gas chromatographic separation was performed on a DB-5HT (15 m × 0.25 mm i.d., 0.25 μm film thickness, J&W Scientific, Folsom, CA, USA) capillary column, with temperature program increased from 110 °C (held for 1 min) to 320 °C at 8 °C/min (held for 3 min). The ionization temperature and interface temperature were set at 150 °C and 280 °C, respectively. The m/zs for tri- to nona-BDE congeners (79, 81),
BDE-209 (79, 81, 486, 488),
13
C12-PCB-141 (372, 374),
13
C12-PCB-208 (476, 478)
and 13C12-BDE-209 (414, 492) were selected. The 12 BDE congeners investigated in this study were BDE-28, -47, -100, -99, -154, -153, -183, -203, -208, -207, -206, and -209 (in order of retention times). 8
Page 8 of 41
Acetone, hexane, and dichloromethane (Sinopharm Chemical Reagent Co., Ltd, Shanghai, China) were of pesticide grade with purity > 98.0%. Standards of BDE congeners and 13C12-labeled PCB congeners were purchased from Accustandard (J&K
ip t
CHEMICA, New Haven, CT, USA).
cr
2.4. QA/QC
us
A procedure blank, a standard spiked blank, and triplicate samples were run with each batch of samples to ensure the accuracy and reproducibility. No detectable target
an
substances were found in blanks. The average recoveries for surrogate standard ranged from 85.2-105.4%. For each sample, PBDEs concentrations were the average
M
of 3 parallel testing results, and differences between duplicate samples were typically less than 30%. The limit of detection (signal/noise of 3) ranged from 0.2 to 2.5 ng/g
d
for tri- to nona-BDE and 50 ng/g for BDE-209 in PM and dust samples, and ranged
Ac ce p
te
from 0.083 to 0.16 pg/m3 for tri- to hepta-BDE in PUF samples.
3. Results and discussion
3.1. Concentrations of TSP, PM10 and PM2.5 (Figure 1)
The mass concentrations of PM2.5, PM10, and TSP in the warehouse and 4
workshops were shown in Figure 1. Mean concentrations at 4 workshops ranged in 103-230 μg/m3, 335-802 μg/m3, 442-1512 μg/m3 for PM2.5, PM10, and TSP, respectively.
According
to
the
Chinese
Ambient
Air
Quality
Standards
(GB3095-2012), the secondary standards for PM2.5, PM10, and TSP were 75, 150, and 9
Page 9 of 41
300 μg/m3, respectively. Obviously, the mass concentrations of PM2.5, PM10, and TSP at the 4 workshops were higher than the secondary standards, while PM concentrations in the warehouse was lower than the secondary standards, indicating
ip t
that ambient air in the workshops was seriously contaminated by TV recycling
cr
activities.
us
Particulate emissions to air within the plants were related to several factors, such as the amount of dust contained within TV sets, the recycling method and equipment
an
used, and the air circulation within the workshop. Most of the collected TV sets had been used and/or stored for several years, and significant amount of dust collected
M
outside as well as inside the TV sets. This dust was mobilized during the recycling process to the ambient air. The highest PM10 and TSP concentrations were obtained in
te
d
the TV dismantling workshop, with the mean values of 802 and 1512 μg/m3. TSP mass concentration at TV dismantling workshop in this study was lower than those in
Ac ce p
other e-waste dismantling halls in Sweden (3.3 mg/m3) [24] and in Guiyu (2.21 mg/m3) [25], China. However, the PM2.5/PM10 (0.27) in TV dismantling workshop was the lowest, indicating that suspended PM was mainly in the form of coarse particles emitted from dust collected outside as well as inside the TV sets. To our surprise, the highest value for PM2.5 occurred in PWB heating workshop (230 μg /m3).
This may be explained by the fact that the room temperature in PWB heating workshop was higher than other sampling sites due to the usage of electric stoves, and many working fans led to better air circulation, resulting in more fine particles captured by the air samplers. Furthermore, the recycling process in the PWB recycling 10
Page 10 of 41
workshop was equipped with cyclone dust extractor, and the air circulation in the plastic crushing workshop was effective as the workshop has open-sided structure. So
workshops were less than in the TV dismantling workshop.
cr
3.2. PBDE concentrations and congener compositions in air
ip t
the levels of particulate pollution in the PWB recycling and plastic crushing
us
(Table 1)
Total PBDE concentration combined from both gas with particulates varied
an
significantly among different workshops, as summarized in Table 1. Tri- to hepta-BDE were present in gaseous phase and PM10 while octa- to deca-BDEs were
M
detected only on the glass fibers indicating these higher brominated PBDE were associated primarily with the particulate phase. These results were in agreement with
te
d
the finding of previous study [22]. The concentrations of
at 4 workshops were in the order of plastic
Ac ce p
crushing > PWB heating > TV dismantling > PWB heating, with the range of 6780 -2280000 pg/m3. Total PBDE concentrations in the workshops were higher than in the warehouse (1310 pg/m3). Yu et al. [9] found that the concentration of particle-bound in the outside air in Pudong district, Shanghai (the location of recycling
plant in this paper) was 310 pg/m3. This indicated that human activities of recycling
TV sets would lead to air pollution of PBDEs. There were some reports on PBDEs in e-waste recycling plant, mainly focusing on e-waste dismantling. These published data are comparable to the results obtained at TV dismantling workshop. For example, it was reported that air concentrations of PBDEs in a dismantling hall in Sweden were 11
Page 11 of 41
0.35-2.1 ng/m3 for BDE-47, 0.54-5.5 ng/m3 for BDE-99, and 12-70 ng/m3 for BDE-209 [24]. Cahill et al. [26] obtained average concentration of total PBDEs in air samples collected inside the dismantling hall of an electronics recycling facility in
ip t
USA was 650000 pg/m3. The mean concentrations of PBDEs ranged from 21 to 2320
cr
ng/m3 at a WEEE recycling site in Finland [27]. However, the level of PBDEs in air at
us
e-waste recycling house in Vietnamese (620-720 pg/m3) [28] was lower than that in this study. The comparison of PBDE concentrations between recycling plant/house in
an
different regions indicated that the complicated mechanism of PBDE emission was related to several factors, such as the structure and size of the building, WEEE
M
category, throughput, recycling process and so on.
The highest concentration of PBDEs in gas was detected at PWB heating workshop,
te
d
and the value (291000 pg/m3) was approximately 2-4 orders of magnitude higher than those in other sampling sites. BDE-28, -47, and -99 were the most abundant
Ac ce p
congeners in the air, accounting for 28.6%, 60.5%, and 7.8% of the gaseous phase. Volatilization of a chemical and its presence in air is driven by the vapor pressure of the chemical, and vapor pressures of PBDE increase with decreasing molecular weight and degree of bromination [29]. The chamber studies [30,31] showed that the greater the vapor pressure, the more likely the BDE congener will volatilize from the plastic product into the air. In other words, the lower brominated BDE congeners with great vapor pressure were easier to migrate from the PWB matrix to the air during heating process under high temperature (about 200-300 °C) than under normal temperature (25-35 °C). 12
Page 12 of 41
concentration of 2280000 pg/m3 was
In the PM10 samples, the highest
obtained at plastic crushing workshop, and BDE-209 accounted for 95.2% of total PBDEs. More information on PBDEs in PM will be discussed in the forthcoming
ip t
section.
cr
(Figure 2)
us
It is interesting to compare the PBDE congener compositions in air (both gaseous and particulate phases) at different workshops as shown in Figure 2. Congener profile
an
of PBDEs at PWB heating workshop was obviously different from others. The ratio for BDE-47 and BDE-99 at PWB heating workshop was the highest (together
M
accounting for 70.4%), indicating the source of penta-BDE mixture existed during the PWB heating process. A high portion of BDE-209 (over 98%) was found in both TV
te
d
dismantling and plastic crushing workshops, which can be explained by the existence of deca-BDE contained in plastic surface dust and plastic materials as shown in Table
Ac ce p
2 [5]. The profile compositions of PBDEs in the warehouse and at PWB recycling workshop were similar, and BDE-209 was the main congener. The reasons for explaining the PBDEs air pollution were complicated, and the
proportion of PBDE congeners were intimately related to the PBDEs-containing products and dust collected on the surface of products. During the use phase of TV sets, the TV sets containing PBDEs mixture might off-gas PBDEs into the surrounding air, then transfer PBDE congener concentrations to interior dust [32]. Another chamber testing showed that when TV sets were placed into test chamber, and PBDEs were detected in air samples taken at the outlet of the chamber [30]. The 13
Page 13 of 41
concentrations and profiles of PBDEs were different in various TV materials and surface dust, leading to different PBDEs emission when waste TV sets were subjected
3.3. PBDEs concentrations and congener composition in PM
cr
(Table 2)
ip t
to dismantling, crushing, and disposal processes.
us
The concentrations of PBDEs per gram PM by weight were used to describe PBDEs in PM. The mean concentrations of penta-BDE, octa-BDE, deca-BDE, and
an
associated with PM2.5 and PM10 are listed in Table 2. PBDE concentrations in PWB, housing plastic, surface dust from PWB and housing plastic,
M
and floor dust in the warehouse and TV dismantling workshop investigated in our previous study were also cited in Table 2 [5]. The PBDE concentrations in PM2.5 and concentrations for PM2.5 and PM10
te
d
PM10 were varying, and the highest
were obtained in the plastic crushing workshop, followed by PWB heating and TV
Ac ce p
dismantling workshop. The amount of PBDEs sorbed to aerially suspended dust inside the workshops was decided not only by PM size, but also by formation and growth of particles, chemical and physical properties, sources of PM, or even partition between vapor and particle phases. For example, if the concentration of organic fraction in PM10 was lower than in PM2.5, the PBDEs in PM10 may lower than in
PM2.5. Further study on the relationship between PM size and the adsorbability of PBDEs is needed. (Figure 3) When TV sets were disassembled in the dismantling workshop, large quantities of 14
Page 14 of 41
dust were released from the TV waste, resulting in heavily particulate pollution as described in the above section. So PBDEs dispersed uniformly in both fine and course airborne particles, and PBDE profiles in PM2.5 and PM10 at TV dismantling workshop
ip t
showed the same characteristics (Figure 3a), in which BDE-209 was the dominant
cr
congener with a contribution of 99% ∑PBDEs. This result is explained that BDE-209
us
was easily affiliated to airborne particles, and generous amount of suspended particles in the TV dismantling workshop were captured by air samplers, leading to high
an
proportion of BDE-209.
The total concentrations of PBDEs in PM at PWB heating workshop were 3740
M
μg/g for PM2.5 and 1220 μg/g for PM10, and the ratios of BDE-209 were both less than 10%, indicating high percentages of lower molecular congeners in the indoor air in
te
d
the PWB heating workshop. It is noticeable that the penta-BDE in PM (accounting for 95.5% in PM2.5 and 88.5% in PM10) were quite abundant in the PWB heating
Ac ce p
workshop. As described, the PWB were produced decades ago, and commercial penta-BDE products prevailed at that time. The congener compositions in PM were consistent with the profile of the commercial penta-BDE products (DE-71 and 70-5DE) as shown in Figure 3b [33]. BDE-47, -99, and -100 were the most abundant congeners in the PWB heating workshop, accounting for 44.3%, 32.8%, and 11.3% of in PM2.5. Two heating stoves with 300 °C were working in the small PWB heating workshop with an area of about 24 square meters, and room temperature was about 30-35 °C. When PWB were suffered from heating process, the lower brominated PBDEs contained in PWB matrix tended to volatilize to the air 15
Page 15 of 41
microenvironment. Kemmlein et al. [31] found that the emission concentrations of BDE-28 and BDE-47 from a PWB increased significantly when raising the temperature from 23 °C to 60 °C in an emission test cell, proving the temperature was
ip t
a factor affecting the emission of PBDEs. As previously mentioned, large quantities of
cr
lower brominated PBDE were emitted from the PWB waste during the heating
us
process, and the indoor air were intensively filled with lower brominated PBDE both in gas and particulate phases. Comparing the PBDE congener compositions in PM at
an
PWB heating workshop with those in commercial penta-BDE mixture [33] and in PWB surface dust, it can obtain the result that lower brominated PBDEs were mainly
M
from PBDEs-containing PWB matrix, and BDE-209 mainly originated from PWB surface dust. The source of BDE-209 on PWB surface dust included: (1) volatilization
te
d
from deca-BDE mixture contained in housing plastics during the usage and product life of TV sets. Hirai et al., [30] calculated emission factors for BDE-209 of 2.8 ×
Ac ce p
10-6/tv/year, when the TV sets were placed in a chamber for 48-hour operation. (2) Dust on PWB surface collected from the surrounding environment when the TV set was used or stored.
The values of PBDEs concentrations in PM at the PWB recycling workshop were
significantly lower than those at PWB heating workshop as shown in Table 2. This result was related to the source of PM and the recycling process. PM in the PWB recycling workshop come from two sources: (1) surface dust in PWB, (2) dust leakage from the cracks appeared among the machines. Pieces of PWB were carried to the feed inlet of the crusher on a conveyer belt before the PWB underwent crushing and 16
Page 16 of 41
separating. The conveyer belt was shaking when conveying the PWB, which actuated the PWB’s surface dust to the air. The concentration and profile in PWB’s surface dust were shown in Table 2 and Figure 3b, respectively. After the PWB entered the crusher,
ip t
the closed mechanical recycling system did not generated severely particulate
cr
pollution, only dust leakage from the cracks appeared among the machines. Because
us
the machines were equipped with pulse-jet bag series dust filter and cyclone dust extractor, and the crushed particles were delivered by pipeline transportation system.
an
However, the pulse-jet bag series dust filter and the air outlet of the cyclone dust extractor, both of which were fixed outside the PWB recycling workshop, may cause
M
outdoor air pollution, which needed further study.
The concentration values of total PBDEs at plastic crushing workshop were 6670
te
d
μg/g in PM2.5 and 6790 μg/g in PM10, and BDE-209 was the main congener, accounting for 95 % of
. The higher brominated PBDE profiles in PM
Ac ce p
were consistent with the profiles of surface dust of housing plastic and the formulations of commercial deca-BDE products (102E and 82-0DE) as shown in Table 2 and Figure 3c [33].
The release mechanism of PBDEs was related to several factors, such as the
compositions of TV sets, interior dust, and the processing. PBDEs contained in TV sets may volatile toward the neighborhood in the form of gas or particles. PBDE emission from TV waste can be explained by the following two mechanisms: (1) Volatilization is one of the mechanisms of release from the PBDEs-containing product into the ambient air. PBDEs was added to the plastic and not covalently bonded with 17
Page 17 of 41
the plastic. It is possible for PBDEs emission from the PWB matrix during the volatilization process. Kemmlein et al. [31] determined PBDE emission by placing products treated with PBDEs into an enclosed chamber, passing an air stream over the
ip t
products, and systematically sampling the chamber air over the duration of the
cr
experiment. Obvious emission rate for BDE-47, -99, -100 were observed; (2) a second
us
possible mechanism of PBDEs transferring from TV sets to PM is through the abrasion of PBDE-treated materials [34]. The abrasion causes small polymers
an
particles that become incorporated as suspended PM in air. 3.4. Gas-particle partitioning of PBDEs
M
PBDEs are semivolatile organic compounds (SVOCs), and have the partition behaviors between the vapor and particle phases in air. Partitioning of atmospheric
d
SVOCs between gas and particle phases is also defined by the particle-gas partition
te
coefficient, KP (m3/μg) [35,36]:
Ac ce p
KP (CP / PM10) / CG
where CP and CG are the concentrations (pg/m3) of SVOCs in PM10 and gas phases,
respectively, and the unit of PM10 is μg/m3. Generally speaking, there are two mechanisms to explain the gas-particle partition
of SVOCs, including adsorption onto the aerosol surface and absorption into the aerosol organic matter. The two different mechanisms both lead to a linear relationship between logKP and logPL (sub-cooled liquid vapor pressure of the
analytes), which is expressed as [37]: +b 18
Page 18 of 41
where m and b are constants. The values of PL were temperature dependent, and ) which has been reported by
calculated from the equation (
Tittlemier et al. [36] for the PBDE congeners (BDE-28, -47, -99, -100, -153, -154, and
ip t
-183) studied in this study. Higher brominated PBDE (BDE-203, -206, -207, -208, and
cr
-209) mainly existed in the particulate phase, and they were not discussed in this
us
section.
The relative abundances of PBDEs in sampling sites are shown in Figure S2. In the
an
warehouse, more than half of BDE-28, -47, -99, -154, and -153 were found in the gas phase. For BDE-47, -100, -99, -154, -153, and -183 at TV dismantling and PWB
M
heating workshops, the BDE congeners were dominantly in the particulate phase, with particulate proportion over 68% and 57%, respectively. This result is expected dust
was
d
PBDEs-containing
constantly
released
to
airborne
te
because
microenvironment during dismantling and heating process, leading to a high PBDEs
Ac ce p
concentration in particulate phase. (Table 3)
Generally, slope (m) from plots of logKP vs. logPL can be considered as a
characterize value for evaluating the sorption processes (adsorption or absorption), and the value of m should be close to -1 at the ideal equilibrium. In reality, the m values derived from ambient air sampling often deviate from -1, and thus cannot be taken as indicative for nonequilibrium conditions [39,40]. However, it has been reported that the m values can be used to classify the type of sorption process: (1) m<-1, surface adsorption, (2) m>-0.6, absorption by the organic matter, and (3) -1< 19
Page 19 of 41
m<-0.6 for coexistence of both mechanisms [40]. The m and b values at different sampling sites were shown in Table 3, and the plots of logKP vs. logPL for the PBDEs at different sampling sites were shown in Figure S3. The m values ranged from -0.33
ip t
and -0.67, much larger than -1, indicating the partitioning equilibrium was dominated
cr
by coexistence of adsorption and absorption, or absorption process. The gas-particle
us
partitioning of PBDEs, which was related to the emission source of PBDEs and the recycling process, was disrupted as PBDEs in PM or gas were continuously released
an
during the working time, probably during TV dismantling, PWB heating, PWB crushing, and housing plastic crushing. For example, PBDEs source at TV
M
dismantling workshop originated from the dust interior TV sets (mostly in the particulate phase), while PBDEs source at PWB heating workshop originated from
te
d
PBDEs-containing PWB matrix and PWB surface dust (both in gaseous and particulate phases). The steepest slopes (m = -0.67) was obtained in the PWB heating
Ac ce p
workshop, and a high coefficient was noted between logKP and logPL (r2=0.84, P<0.0001). This may be due to the higher temperature caused by electric stove in the PWB heating workshop. Jin et al., [41] had obtained similar results that relatively higher equilibrium could be achieved at higher temperature. As a result, the gas-particle partitioning of PBDEs was complicated, and it was essentially controlled by source concentration, temperature, and physical-chemical properties of PBDE congeners, such as vapor pressure (VP), octanol air partition coefficient (Koa). Further study on mechanism of gas-particle partitioning of PBDEs at different workshops is needed. 20
Page 20 of 41
3.5. Health risk assessment of PBDEs exposure through inhalation Generally, inhalation of atmospheric air (both gas and PM10) is one of the primary means of human exposure to PBDEs [42]. Therefore, the inhalation exposure of total
ip t
PBDE concentration is calculated using the PBDE from PM10 and gas. In the case of
cr
WEEE recycling, workers at different recycling workshops inhaled pollutant air with
us
various levels of PBDEs contaminants. The average daily human intake of PBDEs via inhalation (assuming 100% absorption of intake) can be calculated using the
an
following equations [25]: :
M
is the daily occupational exposure via inhalation (ng of
Where
/person/day); CG, CP is the PBDE concentration (ng/m3) in the gaseous phase
d
and PM10, respectively. Work time (Tw), inhalation rate (Ir), and body weight (BW)
Ac ce p
According to total
te
were assumed to be 8 h, 3 m3/h [43], and 70 kg for each worker. concentrations at the 4 workshops (Table 1), it can
be concluded that the highest exposure site was plastic crushing workshop (782 ng/kg/day), followed by PWB heating (244 ng/kg/day) and TV dismantling (82.3 ng/kg/day). The lowest was 2.32 ng/kg/day at PWB recycling workshop. The 3M Particulate Respirator (Model 9032 KN90) was selected for the workers as
it provided good filtration performance with 90% efficiency against non-oil particulates. It is hypothesized that only 10% particulates and total gas were absorbed by air inhalation under the circumstance of wearing a facemask. In addition, the workers during working time were well protected by facemasks, goggles, dust cap, 21
Page 21 of 41
gloves, and clothing, and the dermal exposure was not evaluated in this study. So the average daily PBDEs intake of workers with facemask via inhalation can be
ip t
calculated using the following equations:
cr
(Table 4)
us
A comparison of BDE-congener exposure via the inhalation for different workshop workers is given in Table 4. BDE-47, -99, and -209 are the dominant congeners for
an
the inhalation exposure. The occupational inhalation exposure for BDE-47, -99, -153, and -209 were compared with the reference dose (RfD), as reported by U.S. EPA
M
Integrated Risk Information System. The draft RfD value was 0.1 μg/kg/day for BDE-47, -99, 0.2 μg/kg/day for BDE-153, and 7 μg/kg/day for BDE-209 [44].
te
d
Accordingly, the workers without facemask at PWB heating workshop had the exposure levels of 0.118, 0.0544, and 0.0151 μg/kg/day for BDE-47, BDE-99, and
Ac ce p
BDE-209, respectively. The exposure concentration of BDE-47 for workers without facemask (0.118 μg/kg/day) was higher than the draft RfD (0.1 μg/kg/day), posing a
health hazard to humans. However, when the workers wore the facemasks, the exposure risk decreased, and the exposure concentration of BDE-47 (0.0661 μg/kg/day) was lower than draft RfD. In addition, the exposure concentration of
BDE-99 (0.0544 μg/kg/day) for workers without facemask at PWB heating workshop was close to the draft RfD (0.1 μg/kg/day), showing potential health hazard to workers. From the viewpoint of health protection, wearing a facemask appeared to abrogate the adverse effects of air pollution at workshops, and had the potential to 22
Page 22 of 41
protect the workers from high concentrations of ambient PBDE pollution.
4. Conclusions
ip t
In summary, recycling of waste CRT-TV sets was an important source of PBDEs
cr
emission. BDE-209 in indoor air was mainly released from the TV dismantling and
us
plastic crushing process, while lower brominated PBDE originated from the PWB heating process. The gas-particle partitioning of PBDEs was disrupted by the constant
an
PBDEs emission during TV recycling process. The highest occupational exposure concentrations of BDE congeners occurred in the PWB heating workshop, posing a
d te
Acknowledgments
M
health hazard to workers.
This work was financially supported by the National Natural Science Foundation of
Ac ce p
China (21077071, 21307030). We would also appreciate the anonymous referees for their helpful comments on this paper.
Appendix A. Supplementary data Information for sampling sites (Table S1), recycling processes for waste CRT-TV
sets (Figure S1), relative distribution of PBDEs in air (Figure S2), and plots of logKP vs. logPL for PBDEs (Figure S3) are available.
References 23
Page 23 of 41
[1] MOFCOM (Ministry of Commerce of the People’s Republic of China), 2011. Available at: http://www.mofcom.gov.cn/aarticle/difang/henan/201106/20110607624819.html
ip t
[2] Q. Song, Z. Wang, J. Li, X. Zeng, Life cycle assessment of TV sets in China: A
cr
case study of the impacts of CRT monitors, Waste Manage. 32 (2012) 1926-1936.
us
[3] W. Fang, Y. Yang, Z. Xu, PM10 and PM2.5 and health risk assessment for heavy metals in a typical factory for cathode ray tube television recycling, Environ. Sci.
an
Technol. 47 (2013) 12469-12476.
[4] P.A. Wäger, M. Schluep, E. Müller, R. Gloor, RoHS regulated substances in
Technol. 46 (2012) 628-635.
M
mixed plastics from waste electrical and electronic equipment, Environ. Sci.
te
d
[5] J. Deng, J. Guo, X. Zhou, P. Zhou, X. Fu, W. Zhang, K. Lin, Hazardous substances in indoor dust emitted from waste TV recycling facility. Environ. Sci.
Ac ce p
Pollut. Res. 21 (2014) 7656-7667.
[6] UNEP, Stockholm Convention on Persistent Organic Pollutants (POPs). The 9 new POPs risk management evaluations 2005-2008 (POPRC1-POPRC4). Secretariat of the Stockholm Convention. United Nations Environment Programme. Switzerland, 2009.
[7] M. Yang, H. Jia, W. Ma, H. Qi, S. Cui, Y. Li, Levels, compositions, and gas-particle partitioning of polybrominated diphenyl ethers and dechlorane plus in air in a Chinese northeastern city, Atmos. Environ. 55 (2012) 73-79. [8] X. Qiu, T. Zhu, J. Hu, Polybrominated diphenyl ethers (PBDEs) and other flame 24
Page 24 of 41
retardants in the atmosphere and water from Taihu Lake, east China, Chemosphere 80 (2010) 1207-1212. [9] Z. Yu, R.E. Liao, H. Li, L. Mo, X. Zeng, G. Sheng, J. Fu, Particle-bound
cr
Shanghai, China, Environ. Pollut. 159 (2011) 2982-2988.
ip t
Dechlorane Plus and polybrominated diphenyl ethers in ambient air around
us
[10] M. Tian, S. Chen, J. Wang, X. Zheng, X. Luo, B. Mai, Brominated flame retardants in the atmosphere of e-waste and rural sites in southern China: Seasonal
an
variation, temperature dependence, and gas-particle partitioning, Environ. Sci. Technol. 45 (2011) 8819-8825.
M
[11] X. Bi, B.R.T. Simoneit, Z. Wang, X. Wang, G. Sheng, J. Fu, The major components of particles emitted during recycling of waste printed circuit boards in
4440-4445.
te
d
a typical e-waste workshop of south China, Atmos. Environ. 44 (2010)
Ac ce p
[12] Z. Gu, J. Feng, W. Han, M. Wu, J. Fu, G. Sheng, Characteristics of organic matter in PM2.5 from an e-waste dismantling area in Taizhou, China, Chemosphere 80 (2010) 800-806.
[13] Y. Li, G. Jiang, Y. Wang, P. Wang, Q. Zhang, Concentrations, profiles and gas-particle partitioning of PCDD/Fs, PCBs and PBDEs in the ambient air of an e-waste dismantling area, southeast China, Chin. Sci. Bull. 53 (2008) 521-528. (in Chinese) [14] T. Zhang, Y. Huang, S. Chen, A. Liu, P. Xu, N. Li, L. Qi, Y. Ren, Z. Zhou, B. Mai, PCDD/Fs, PBDD/Fs, and PBDEs in the air of an e-waste recycling area 25
Page 25 of 41
(Taizhou) in China: current levels, composition profiles, and potential cancer risks, J. Environ. Monitor. 14 (2012) 3156-3163. [15] W. Han, J. Feng, Z. Gu, D. Chen, M. Wu, J. Fu, Polybrominated diphenyl ethers
ip t
in the atmosphere of Taizhou, a major e-waste dismantling area in China, Bull.
cr
Environ. Contam. Toxicol. 83 (2009) 783-788.
us
[16] A.O.W. Leung, J. Zheng, C.K. Yu, W.K. Liu, C.K.C. Wong, Z. Cai, M.H. Wong, Polybrominated diphenyl ethers and polychlorinated dibenzo-p-dioxins and
an
dibenzofurans in surface dust at an e-waste processing site in southeast China, Environ. Sci. Technol. 45 (2011) 5775-5782.
M
[17] WHO., Outdoor air pollution a leading environmental cause of cancer deaths. International Agency for Research on Cancer, World Health Organization, 2013.
October 2013)
(accessed
20
te
d
http://www.iarc.fr/en/media-centre/iarcnews/pdf/pr221_E.pdf
Ac ce p
[18] W.J. Deng, J.S. Zheng, X.H. Bi, J.M. Fu, M.H. Wong, Distribution of PBDEs in air particles from an electronic waste recycling site compared with Guangzhou and Hong Kong, south China, Environ. Int. 33 (2007) 1063-1069.
[19] C.A. de Wit, J.A. Björklund, K. Thuresson, Tri-decabrominated diphenyl ethers and hexabromocyclododecane in indoor air and dust from Stockholm microenvironments 2: Indoor sources and human exposure, Environ. Int. 39 (2012) 141-147. [20] J.A. Björklund, K. Thuresson, A.P. Cousins, U. Sellström, G. Emenius, C.A. de Wit, Indoor air is a significant source of tri-decabrominated diphenyl ethers to 26
Page 26 of 41
outdoor air via ventilation systems, Environ. Sci. Technol. 46 (2012) 5876-5884. [21] D. Muenhor, S. Harrad, Within-room and within-building temporal and spatial variations in concentrations of polybrominated diphenyl ethers (PBDEs) in indoor
ip t
dust, Environ. Int. 47 (2012) 23-27.
cr
[22] M.A. Abdallah, S. Harrad, Modification and calibration of a passive air sampler
us
for monitoring vapor and particulate phase brominated flame retardants in indoor air: Application to car interiors, Environ. Sci. Technol. 44 (2010) 3059-3065.
an
[23] J.G. Allen, A.L. Sumner, M.G. Nishioka, J. Vallarino, D.J. Turner, H.K. Saltman, J.D. Spengler, Air concentrations of PBDEs on in-flight airplanes and assessment
M
of flight crew inhalation exposure, J. Expo. Sci. Environ. Epid. 23 (2012) 337-342.
Å. Bergman, C. Östman,.
te
d
[24] A. Sjödin, H.A. Carlsson, K. Thuresson, S. Sjölin,
Flame retardants in indoor air at an electronics recycling plant and at other work
Ac ce p
environments, Environ. Sci. Technol. 35 (2001) 448-454.
[25] T. An, D. Zhang, G. Li, B. Mai, J. Fu, On-site and off-site atmospheric PBDEs in an electronic dismantling workshop in south China: Gas-particle partitioning and human exposure assessment, Environ. Pollut. 159 (2011) 3529-3535.
[26] T.M. Cahill, D. Groskova, M.J. Charles, J.R. Sanborn, M.S. Denison, L. Baker, Atmospheric concentrations of polybrominated diphenyl ethers at near-source sites, Environ. Sci. Technol. 41 (2007) 6370-6377. [27] C. Rosenberg, M. Hämeilä, J. Tornaeus, K. Säkkinen, K. Puttonen, A. Korpi, M. Kiilunen, M. Linnainmaa, A. Hesso, Exposure to flame retardants in electronics 27
Page 27 of 41
recycling sites, Ann. Occup. Hyg. 55 (2011) 658-665. [28] N.M. Tue, S. Takahashi, G. Suzuki, T. Isobe, P.H. Viet, Y. Kobara, N. Seike, G. Zhang, A. Sudaryanto, S. Tanabe, Contamination of indoor dust and air by
ip t
polychlorinated biphenyls and brominated flame retardants and relevance of
cr
non-dietary exposure in Vietnamese informal e-waste recycling sites, Environ. Int.
us
51 (2013) 160-167.
[29] USEPA, An exposure assessment of polybrominated diphenyl ethers,
Technical
Information
an
(EPA/600/R-08/086F); Washington DC, 2010. Available from the National Service,
VA,
and
online
at
M
http://www.epa.gov/ncea.
Springfield,
[30] Y. Hirai, S. Sakai, K. Sato, K. Hayakawa, K. Shiozaki, Emission of brominated
te
d
flame retardants from TV sets, Organohalogen Compd. 68 (2006) 1772-1775. [31] S. Kemmlein, O. Hahn, O. Jann, Emissions of organophosphate and brominated
Ac ce p
flame retardants from selected consumer products and building materials, Atmos. Environ. 37 (2003) 5485-5493.
[32] H. Takigami, G. Suzuki, Y. Hirai, S. Sakai, Transfer of brominated flame retardants from components into dust inside television cabinets, Chemosphere 73 (2008) 161-169.
[33] M.J. La Guardia, R.C. Hale, E. Harvey, Detailed polybrominated diphenyl ether (PBDE) congener composition of the widely used Penta-, Octa-, and Deca-PBDE technical flame-retardant mixtures, Environ. Sci. Technol. 40 (2006) 6247-6254. [34] T.F. Webster, S. Harrad, J.R. Millette, R.D. Holbrook, J.M. Davis, H.M. 28
Page 28 of 41
Stapleton, J.G. Allen, M.D. McClean, C. Ibarra, M.A. Abdallah, A. Covaci, Identifying transfer mechanisms and sources of decabromodiphenyl ether (BDE 209) in indoor environments using environmental forensic microscopy, Environ.
ip t
Sci. Technol. 43 (2009) 3067-3072.
cr
[35] T. Harner, T.F. Bidleman, Octanol-air partition coefficient for describing
us
particle/gas partitioning of aromatic compounds in urban air, Environ. Sci. Technol. 32 (1998) 1494-1502.
an
[36] M. Yang, H. Qi, H. Jia, N. Ren, Y. Ding, W. Ma, L. Liu, H. Hung, E. Sverko, Y. Li, Polybrominated diphenyl ethers in air across China: levels, compositions,
M
and gas-particle partitioning, Environ. Sci. Technol. 47 (2013) 8978-8984. [37] D. Chen, X. Bi, J. Zhao, L. Chen, J. Tan, B. Mai, G. Sheng, J. Fu, M.H. Wong,
te
d
Pollution characterization and diurnal variation of PBDEs in the atmosphere of an e-waste dismantling region, Environ. Pollut. 157 (2009) 1051-1057.
Ac ce p
[38] S.A. Tittlemier, T. Halldorson, G.A. Stern, G.T. Tomy, Vapor pressures, aqueous solubilities, and Henry's law constants of some brominated flame retardants, Environ. Toxicol. Chem. 21 (2002) 1804-1810.
[39] J.F. Pankow, T.F. Bidleman, Interdependence of the slopes and intercepts from log-log correlations of measured gas-particle partitioning and vapor pressure-I. Theory and analysis of available data, Atmos. Environ. 26A (1992) 1071-1080. [40] K.U. Goss, R.P. Schwarzenbach, Gas/solid and gas/liquid partitioning of organic compounds: Critical evaluation of the interpretation of equilibrium constants, Environ. Sci. Technol. 32 (1998) 2025-2032. 29
Page 29 of 41
[41] J. Jin, Y. Wang, W. Liu, C. Yang, J. Hu, J. Cui, Polybrominated diphenyl ethers in atmosphere and soil of a production area in China: Levels and partitioning, J. Environ. Sci. (China), 23 (2011) 427-433.
ip t
[42] S. Harrad, S. Hazrati, C. Ibarra, Concentrations of polychlorinated biphenyls in
cr
indoor air and polybrominated diphenyl ethers in indoor air and dust in
us
Birmingham, United Kingdom: Implications for human exposure, Environ. Sci. Technol. 40 (2006) 4633-4638.
an
[43] USEPA, Exposure Factors Handbook: 2011 Edition. National Center for Environmental Assessment, (EPA/600/R-09/052F); Washington DC, 2011.
M
Available from the National Technical Information Service, Springfield, VA, and online at http://www.epa.gov/ncea/efh.
te
d
[44] USEPA, Integrated Risk Information System: 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) (CASRN 5436-43-1), http://www.epa.gov/iris/subst/1010.htm (accessed 2013);
Ac ce p
October
Integrated
2,2',4,4',5-Pentabromodiphenyl
Risk
ether
(BDE-99)
Information (CASRN
System: 60348-60-9),
http://www.epa.gov/iris/subst/1008.htm (accessed October 2013); Integrated Risk
Information System: 2,2',4,4',5,5'-Hexabromodiphenyl ether (BDE-153) (CASRN 68631-49-2), http://www.epa.gov/iris/subst/1009.htm (accessed October 2013);
Integrated Risk Information System: 2,2',3,3',4,4',5,5',6,6'-Decabromodiphenyl ether (BDE-209) (CASRN 1163-19-5), http://www.epa.gov/iris/subst/0035.htm (accessed 17 October 2013).
30
Page 30 of 41
Table and Figure legends
ip t
Table 1. Mean Concentrations (sd) of PBDEs in the Air (PM10 and gas phase) of Different Sampling Sites (pg/m3)
cr
Table 2. PBDEs Concentrations in PM2.5 and PM10 at Different Sampling Sites (μg/g) Table 3. Linear Relationship between logKP and logPL of PBDEs at Different
us
Sampling Sites
an
Table 4. Inhalation Exposure of PBDE Congeners -47, -99, -153, and -209 for
M
Workers with or without Facemask (μg/kg/day)
Figure 1. Mean concentrations of PM2.5, PM10 and TSP at different sampling sites.
te
sampling sites.
d
Figure 2. Congener contributions in air (both gas phase and PM10) at different
Ac ce p
Figure 3. Congener contributions in PM, dust, and commercial mixtures.
31
Page 31 of 41
ip t cr
warehouse
TV dismantling
us
Table 1. Mean Concentrations of PBDEs in the Air (PM10 and gas phase) of Different Sampling Sites (pg/m3) PWB heating
PWB recycling
Plastic crushing
gas
PM10
gas
PM10
gas
PM10
gas
PM10
gas
BDE-28
1.19
32.7
66.7
898
16200
83100
26.0
117
137
983
BDE-47
9.91
37.4
458
322
167000
176000
251
318
2990
3190
BDE-100
0.72
0.57
117
17.4
51100
8660
10.9
9.06
136
117
BDE-99
11.8
7.63
882
111
136000
22600
314
92.5
2180
22.0
BDE-154
0.43
0.86
77.7
7.17
4340
184
3.50
4.83
60.8
38.4
BDE-153
1.54
1.68
364
2.72
1610
616
20.0
15.7
771
145
BDE-183
4.70
0.48
273
0.78
950
25.3
4.64
0.83
4800
90.3
BDE-203
3.97
-
4.37
-
24.3
-
15.2
-
3370
-
BDE-208
17.8
-
1080
-
538
-
36.3
-
12000
-
BDE-207
5.18
-
352
-
61. 5
-
23.3
-
12100
-
BDE-206
50.0
-
3230
-
577
-
223
-
71900
-
BDE-209
1120
-
232000
-
44000
-
5290
-
2170000
-
239000
-
422000
-
6220
-
2280000
-
ed
ce pt
Ac
1230
81.2
Total
1310
M an
PM10
1360
291000
240000
713000
558 6780
4580 2280000
32
Page 32 of 41
ip t cr us
Table 2. PBDEs Concentrations in PM2.5 and PM10 at Different Sampling Sites (μg/g) TV dismantling
PM10
floor dustd
PM2.5
PM10
floor dustd
penta-BDEa
0.17
0.33
1.51
3.81
2.47
1.50
octa-BDEb
0.19
0.11
2.64
0.47
0.35
1.38
deca-BDEc
8.99
16.4
180
472
320
9.35
16.8
184
476
323
Plastic crushing
PM10
PM2.5
PM10
PWBd
PWB dustd
PM2.5
PM10
plasticd
plastic dustd
3570
1080
4.98
0.27
6030
20.0
40.5
18.7
1.45
6.61
4.48
2.81
2.94
0.093
6.02
0.32
33.4
24.4
4.11
2.91
100
168
138
8.91
32.2
5.35
52.6
6600
6750
6920
102
103
3740
1220
16.8
32.6
6044
72.9
6670
6790
6920
112
ce pt
penta-BDE(28, 47, 99, 100, 153, 154), bocta-BDE(183, 203), cdeca-BDE (206, 207, 208, 209) d data cited from Reference [5]
Ac
a
PWB recycling
PM2.5
ed
PM2.5
PWB heating
M an
warehouse
33
Page 33 of 41
ip t cr us
M an
Table 3. Linear Relationship between logKP and logPL of PBDEs at Different Sampling Sites
-0.55
TV dismantling
-0.33
PWB heating
-0.67
PWB recycling
-0.33
Plastic crushing
-0.54
b
r2
P
-4.48
0.58
<0.0001
-4.65
0.25
0.020
-4.54
0.84
<0.0001
-3.62
0.39
2.52E-3
-4.24
0.34
0.046
Ac
ce pt
warehouse
ed
m
34
Page 34 of 41
ip t cr us
Table 4. Inhalation Exposure of PBDE Congeners -47, -99, -153, and -209 for Workers with or without Facemask (μg/kg/day) without facemask TV dismantling
PWB heating
M an
draft RfD
with facemask
PWB recycling
Plastic crushing
TV dismantling
PWB heating
PWB recycling
Plastic crushing
1.95E-04
2.12E-03
1.26E-04
6.61E-02
1.18E-04
1.20E-03
1.39E-04
7.55E-04
6.83E-05
1.24E-02
4.25E-05
8.23E-05
0.1
2.67E-04
0.118
BDE-99
0.1
3.40E-04
5.44E-02
BDE-153
0.2
1.26E-04
7.63E-04
1.22E-05
3.14E-04
1.34E-05
2.66E-04
6.07E-06
7.61E-05
BDE-209
7
7.95E-02
1.51E-02
1.81E-03
7.44E-01
7.95E-03
1.51E-03
1.81E-04
7.44E-02
Ac
ce pt
ed
BDE-47
35
Page 35 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Figure 1
Page 36 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Figure 2
Page 37 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Figure 3a
Page 38 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Figure 3b
Page 39 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Figure 3c
Page 40 of 41
Ac
ce
pt
ed
M
an
us
cr
i
Graphical Abstract (for review)
Page 41 of 41