Mi Tian

Brominated flame retardants in house dust from e-waste recycling and urban areas in South China: Implications on human exposure

Brominated flame retardants (BFRs) were examined in house dust from the electronic waste (e-waste) recycling and urban areas of South China. The concentrations of polybrominated diphenyl ethers (PBDEs) were in the range of 227-160,000 ng/g in the e-waste recycling area and 530-44,000 ng/g in the urban area. These values were much higher than other BFRs, except for novel decabromodiphenyl ethane (DBDPE) whose value of 100-47,000 ng/g was dominant in approximately 1/4 of the samples from the urban area. Urban dust PBDE levels were generally higher than those in many European and Asian countries and comparable to the values found in North America. Urban dust DBDPE levels were higher than those of other areas in the world. The distinct dust BFR profiles observed in the two studied areas were reflective of activities in these areas (electronics industry vs. e-waste recycling). The presence of BDE202, as well as the BDE197 to BDE201 and the nona-BDEs to deca-BDE ratios in the dust samples from the studied areas were probably indicative of environmental degradation of deca-BDE. The estimated daily intakes (EDIs) of average adult and toddler via house dust ranged from 37.0 to 304 ng/day for PBDEs and from 3.01 to 87.6 ng/day for all other BFRs in the studied areas. The EDIs via house dust were much higher than those via other indoor pathways (air, fish, human milk, and toys). Despite the potentially low deleterious risk of PBDE exposure via house dust as suggested by the hazard quotients, this exposure pathway should be of great concern because of the higher BFR exposures for children and the presence of other BFRs (such as DBDPE) which have not yet been fully investigated.

Dechlorane Plus in Human Hair from an E-Waste Recycling Area in South China: Comparison with Dust

Dechlorane Plus (DP) and a dechlorination product, 1,6,7,8,9,14,15,16,17,17,18-octadeca-7,15-diene (anti-Cl(11)-DP), were measured in human hair and indoor dust collected from an e-waste recycling area and two control areas (rural and urban) in South China. DP was detected in hair and dust samples at concentrations ranging from 0.02-58.32 ng/g and 2.78-4197 ng/g, respectively. anti-Cl(11)-DP, mainly detected in human hair and dust samples from the e-waste recycling area, ranged from nd (nondetected) to 0.23 ng/g in hair and from nd to 20.22 ng/g in dust. Average values of anti-DP fractional abundance (f(anti) ratio) in hair of e-waste dismantling workers (0.55 ± 0.11) and dust from e-waste recycling workshops (0.54 ± 0.15) were significantly lower than those in other groups (0.62-0.76 means for hair and 0.66-0.76 means for dust). Significantly positive correlation between DP concentrations in dust and hair and similarity in f(anti) ratios between hair and dust suggest that ingestion of dust comprise one of the major routes for DP exposure. Significantly positive relationships were also observed between anti-Cl(11)-DP and anti-DP for both hair and dust samples with similar regression line slopes. The ratios of anti-Cl(11)-DP to anti-DP between hair and dust show no significant difference. These results suggest that anti-Cl(11)-DP in the human body is likely accumulated from the environmental matrix and not formed from biotransformation of the parent DP.

Brominated Flame Retardants in the Atmosphere of E-Waste and Rural Sites in Southern China: Seasonal Variation, Temperature Dependence, and Gas-Particle Partitioning

The recycling of electrical and electronic waste(e-waste) in developing countries has attracted much attention as a significant source of brominated flame retardants (BFRs).Gaseous and particle-bound BFRs were measured in the atmosphere at e-waste and rural sites in southern China during 2007-2008. The annual average concentrations in the air were 3260 ± 3370 and 219 ± 192 pg/m³ for polybrominated diphenyl ethers (PBDEs) and were 546 ± 547 and 165 ± 144 pg/m³ for non-PBDE BFRs at the e-waste and rural sites,respectively. PBDEs had unusually high relative concentrations of di- and tribrominated congeners at the e-waste site. The Clausius-Clapeyron (CC) plots showed that the gaseous concentrations of less brominated BFRs (di- through hexa-BFRs) were strongly controlled by temperature-driven evaporation from contaminated surfaces (e.g., e-waste, soils, and recycled e-waste remains) except for winter. However, weak temperature dependence at the rural site suggests that regional or long-range atmospheric transport was largely responsible for the air concentrations. Gas-particle partitioning (KP) of PBDEs correlated well with the subcooled liquid vapor pressure (PL(o)) for most sampling events. The varied slopes of log KP versus log PL(o) plots for the e-waste site (-0.59 to -1.29) indicated an influence of ambient temperature and atmospheric particle properties on the partitioning behavior of BFRs. The flat slopes (-0.23 to -0.80) for the rural site implied an absorption-dominant partitioning. This paper suggests that e-waste recycling in Asian low-latitude regions is a significant source of less brominated BFRs and has important implications for their global transport from warm to colder climate

Diffusion of polybrominated diphenyl ether (PBDE) from an e-waste recycling area to the surrounding regions in Southeast China

Using Cinnamomum camphora (C. camphora) leaves as biomonitors, we investigated that the diffusion of polybrominated diphenyl ethers (PBDEs) from an e-waste recycling area to the surrounding regions. Variance in sigma(32)PBDEs concentrations (0.46-399.93 ng g(-1) dry weight) in the leaves showed that PBDEs from the e-waste recycling area diffused into the surrounding regions, and resulted in a halo of PBDEs contamination, at least 74 km in radius. The attenuation of sigma(32)PBDEs in the diffusing process fitted in log-linear regression. The difference in the attenuating slopes of linear equations among different directions can be explained by terrain and wind direction. The attenuation of PBDE congeners also fitted well in log-linear regression. The findings that similar attenuating slopes and characteristic travel distance among congeners suggest that the transport behavior of lower brominated congeners might not differ from that of higher brominated congeners in short-range scale.

Inhalation Cancer Risk Associated with Exposure to Complex Polycyclic Aromatic Hydrocarbon Mixtures in an Electronic Waste and Urban Area in South China

Atmospheric particulate matter samples were collected from May 2010 to April 2011 in a rural e-waste area and in Guangzhou, South China, to estimate the lifetime inhalation cancer risk from exposure to parent polycyclic aromatic hydrocarbons (PAHs), high molecular weight PAHs (MW 302 PAHs), and halogenated PAHs (HPAHs). Seasonal variations in the PAH concentrations and profiles within and between the e-waste and urban areas indicated different PAH sources in the two areas. Benzo[b]fluoranthene, benzo[a]pyrene, dibenz[ah]anthracene, and dibenzo[al]pyrene made the most significant contribution to the inhalation cancer risk. MW 302 PAHs accounted for 18.0% of the total cancer risk in the e-waste area and 13.6% in the urban area, while HPAHs made a minor contribution (<0.1%) in both the areas. The number of lifetime excess lung cancers due to exposure to parent PAHs, MW 302 PAHs, and HPAHs ranged from 15.1 to 1198 per million people in the e-waste area and from 9.3 to 737 per million people in Guangzhou. PAH exposure accounted for 0.02 to 1.94% of the total lung cancer cases in Guangzhou. On average, the inhalation cancer risk in the e-waste area was 1.6 times higher than in the urban area. The e-waste dismantling activities in South China led to higher inhalation cancer risk due to PAH exposure than the urban area.

Occurrence of brominated flame retardants (BFRs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) in agricultural soils in a BFR-manufacturing region of North China

We investigated the occurrence of brominated flame retardants (BFRs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) in the surface soils from the largest BFR-manufacturing and vegetable farming center (Shouguang) of North China. The total concentrations of BFRs ranged from 39.9 to 8,145 ng/g dry weight with a mean of 1,947 ng/g. The BFRs were dominated by decabromodiphenylethane (deca-BDEs) and tetrabromobisphenol A (TBBPA), with means of 1127 and 672 ng/g, respectively, followed by decabromodiphenyl ethane (DBDPE) (111 ng/g) and hexabromocyclododecanes (HBCD) (37.5 ng/g). This profile was generally consistent with the BFR production and use in China, except for TBBPA. Although the lower brominated BDEs (tri- through hepta-BDEs) in the soil may originate from technical deca-BDE mixtures as trace impurities and/or from the degradation of deca-BDEs, deca-BDE was shown to be persistent in the soil. The concentrations of OCPs (44 ng/g) were significantly lower than those of BFRs and displayed a spatial distribution opposite to that of BFRs, which was concentrated in the industrial zone. PCBs (with the lowest levels) showed a relatively uniform spatial distribution because of regional diffusive sources. The mass inventories for the entire land soil (20-cm) were estimated to be 1042, 26, and 3.7 t for BFRs, OCPs, and PCBs, respectively.

Dechlorane Plus (DP) in air and plants at an electronic waste (e-waste) site in South China.

Air and foliage samples (Eucalyptus spp. and Pinus massoniana Lamb.) were collected from e-waste and reference sites in South China and analyzed for Dechlorane Plus (DP) and two dechlorinated DPs. DP concentrations in the air were 13.1-1794 pg/m3 for the e-waste site and 0.47-35.7 pg/m3 for the reference site, suggesting the recycling of e-waste is an important source of DP to the environment. Plant DP, with concentrations of 0.45-51.9 ng/g dry weight at the e-waste site and 0.09-2.46 ng/g at the reference site, exhibited temporal patterns similar to the air DP except for pine needle at the reference site. The air-plant exchange of DP could be described with the two-compartment model. Anti-Cl11 DP was measured in most air and plant samples from the e-waste site. The ratios of anti-Cl11 DP to anti-DP in the air and plants may indicate the preferential uptake of dechlorinated DP by plant compared with DP.

Measurement and human exposure assessment of brominated flame retardants in household products from South China

Brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), and decabromodiphenyl ethane (DBDPE) were examined in household products in the Pearl River Delta, South China, including electronic appliances, furniture and upholstery, car interiors, and raw materials for electronics. The concentrations of PBDEs derived from penta-BDE mixture were much lower (<111 ng/g) than those for octa- and deca-BDE commercially derived PBDEs, with maximum values of 15,107 and 1,603,343 ng/g, respectively, in all the household products. Our findings suggest the recycling of old electronic products and their reuse might be also a potential important source of discontinued PBDEs to the environment. DBDPE was found in 20.0% of all the samples, ranging from 311 to 268,230 ng/g. PBDE congener profiles in both the household products and raw materials suggest that some less brominated BDEs in the environment may be derived from the decomposition of higher brominated PBDEs in PBDE-containing products in process of the manufacturing, use and/or recycling. Human exposure to PBDEs from household products via inhalation ranged from 175 to 612 pg/kg bw day, accounting for a small proportion of the total daily exposure via indoor inhalation. Despite the low deleterious risk associated with household products with regard to PBDEs, they are of special concern because of the relatively higher exposures observed for young children and further work is required.

Plant Uptake of Atmospheric Brominated Flame Retardants at an E-Waste Site in Southern China

Brominated flame retardants (BFRs) were measured in eucalyptus leaves and pine needles as well as the leaf surface particles (LSPs) of the two species at an e-waste site in southern China in 2007-2008. The monthly concentrations of total BFRs in the eucalyptus leaves and pine needles were in range of 30.6-154 and 15.1-236 ng/g dry weight, respectively, and relatively higher concentrations were observed in winter and spring. Correlation analysis of BFR concentrations and comparison of PBDE compositions between the plants and LSPs, air (gaseous and particle-bound phases), and ambient variables were conducted. The results revealed that BFRs in the plants, especially for less brominated BFRs, showed positive relationships with BFRs in the LSPs and negative relationships with the gaseous BFRs and ambient temperature. The PBDE profiles in the plants were similar to the gaseous profile for low brominated BDEs (di- through hexa-BDEs) and to the LSP profiles for highly brominated BDEs (hepta- through deca-BDEs). Applying McLachlans framework to our data suggests that the uptake of BFRs was controlled primarily by gaseous partitioning equilibrium for compounds with log octanol-air partition coefficients (K(OA)) < 12 and by particle-bound deposition for compounds with log K(OA) > 13. Different relationships between the plant/air partition coefficient (K(PA)) and K(OA), which depend on the uptake mechanisms, were observed for polybrominated diphenyl ethers (PBDEs). This paper adds to the current knowledge of the factors and mechanisms governing plant uptake of semivolatile organic compounds with relatively high K(OA) in the environment.

Atmospheric deposition of halogenated flame retardants at urban, e-waste, and rural locations in southern China.

Measurements of atmospheric deposition fluxes and temporal variation of halogenated flame retardants (HFRs) from 2007 to 2008 at urban, electronic waste (e-waste), and rural sites in southern China are presented. The deposition fluxes of total HFRs at the urban (99.3-1327 ng m(-2) day(-1)) and e-waste (79.1-1200 ng m(-2) day(-1)) sites were much higher than at the rural site (9.27-79.5 ng m(-2) day(-1)), demonstrating that e-waste recycling and industrial activities in southern China are two important sources of HFRs in the environment. The urban deposition profile was dominated by current-use HFRs (decabrominated diphenyl ether and decabromodiphenyl ethane), whereas the profile at the e-waste site reflects the past when significant amounts of PBDEs and Dechlorane Plus were used. Source apportionment estimated by principal component analyses with multiple linear regression analysis showed that deposition HFRs at the rural site were primarily contributed by the urban and e-waste sources (45% and 38%, respectively) compared to the contribution from local emission (17%). Our results suggest that the HFRs that are readily present in gas or sorbed onto fine particle phases have enhanced potential for long-range atmospheric transport.