Dietary exposure to PCBs based on food consumption survey and food basket analysis at Taizhou, China--the world's major site for recycling transformers

Health risk assessment and development of human health ambient water quality criteria for PCBs in Taihu Basin, China

Polychlorinated biphenyls (PCBs) are a class of typical persistent organic pollutants (POPs) with carcinogenicity and extensively found in diverse environmental mediums. The Taihu Basin is one of the most economically developed regions in China, and it has also caused a lot of historical legacy and unconscious emissions of PCBs, posing a threat to the health of people in the region. This study counted the concentrations of PCBs in five environmental media (water, soil, air, dust, and food) in the Taihu Basin from 2000 to 2020 and used Monte Carlo simulation to simulate the multi-channel exposure of PCBs in people of different ages (children, teenagers, and adults), and evaluated their noncarcinogenic and carcinogenic health risks. Finally, the human health ambient water quality standards (AWQC) for PCBs were obtained using regional exposure parameters and bioaccumulation factors. The results showed that the pollution of PCBs in the Taihu Basin was relatively serious in China. The concentration of PCBs in dust is higher than other environmental media. And exposure to water and food is the main exposure pathway for PCBs in the population of the region. Besides, PCBs pose no noncarcinogenic risk to people in this region, but their carcinogenic risk to residents exceeds the safety threshold. Among the three population groups, adults have the highest risk of cancer, and prevention measures need to be taken by controlling the intake of related foods and the concentration of PCBs in water. The following human health AWQC values of the PCBs in Taihu Basin is 3.2 × 10-9 mg/L.

The derivation of soil generic assessment criteria for polychlorinated biphenyls under the agricultural land scenario in Pearl and Yangtze River Delta regions, China

The agricultural soils in China are suffered from serious polychlorinated biphenyls (PCBs) contamination, however, the valid management standards for farmland are absent to efficiently control the health risks of PCBs exposure. This study analyzed the contamination characteristics and main composition of PCBs in agricultural soils of the southeastern China from the published literature over the past 20 years, and derived the regional generic assessment criteria (GAC) using an exposure modelling approach for individual and total PCBs (∑PCBs) via multiple exposure pathways such as ingestion of soil and dust, consumption of vegetables, dermal contact with soil and dust, ingestion of soil attached to vegetables, and inhalation of soil vapour and soil-derived dust outdoors under the agricultural land scenario. It is identified that the averaged ∑PCBs concentration of 80.03 ng g^-1 under the 95 % lower confidence limit with an unacceptable health risk of 4.8 × 10^-6 has significantly exceeded the integrated generic assessment criteria (expressed as GAC_int) of 16.5 ng g^-1. Accordingly, the exposure pathways from the consumption of agricultural produces and indirect ingestion of soil attached to vegetables contributed up to 62 %-88 % of the total exposure, followed by 11 %-33 % of the soil ingestion and 2 %-6 % of dermal contact. The derived GAC_int for ∑PCBs is extremely valuable to effectively assess and manage the PCBs contamination in agricultural soils of China.

Pharmacokinetics, withdrawal time, and dietary risk assessment of enrofloxacin and its metabolite ciprofloxacin, and sulfachloropyridazine-trimethoprim in Taihe black-boned silky fowls

Enrofloxacin (ENR) and sulfachloropyridazine combined with trimethoprim (TMP) were commonly used in poultries to treat bacterial infections. In this study, the pharmacokinetics of these antibiotics in four tissues of Taihe black-boned silky fowls was studied. The results showed that these drugs were absorbed and distributed rapidly, with the highest concentration showing in skin. Meanwhile, ENR and its metabolite ciprofloxacin (CIP) and TMP were depleted slowly, particularly in skin with the elimination half-lives being 37.1, 36.9, and 72.7 days, respectively. It may be attributed to the abundance of melanin in skin. The dietary risk assessment suggested that the long-term dietary intakes of ENR, CIP, and TMP showed a considerable threat to human health. Based on the experiment, the withdrawal times of 284 days for ENR + CIP and 159 days for TMP were acquired, which showed that these drugs are not appropriate for the application in Taihe black-boned silky fowls.

Presence of novel and legacy flame retardants and other pollutants in an e-waste site in China and associated risks

Electrical and Electronic Equipment (EEE) residues and their management have been widely identified as potential sources of plasticizers and flame retardants to the environment, especially in non-formal e-waste facilities. This study evaluates the distribution, partitioning and environmental and human impact of organophosphate esters (OPEs), legacy polychlorinated biphenyls (PCBs), polybromodiphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) in the e-waste recycling area of Baihe Tang village, in the Qingyuan county, Guangdong province, China. A plastic debris lump accumulated in a small pond during years was identified as the main source of pollution with ∑pollutants of 8400 μg/g dw, being OPEs the main contaminants detected, followed by PBDEs. This lump produced the contamination of water, sediments, soils and hen eggs in the surrounding area at high concentrations. Plastic-water and water-sediment partitioning coefficients explained the migration of OPEs to the water body and accumulation in sediments, with a strong dependence according to the K_OW. Triphenyl phosphate (TPhP), tricresyl phosphate (TCPs) and high chlorination degree PCBs produced a risk in soils and sediments, considering the lowest predicted no effect concentration, while the presence of PCBs and PBDEs in free range hen eggs exceeded the acceptable daily intake. OCPs were detected at low concentrations in all samples. The presence of organic contaminants in e-waste facilities worldwide is discussed to highlight the need for a strict control of EEE management to minimize environmental and human risks.

Residues of polychlorinated biphenyls (PCBs) in a wild predatory fish from an e-waste site in South China between 2009 and 2016

Crude electronic waste (e-waste) recycling has been banned due to the serious environmental pollution it caused, leaving many abandoned e-waste sites. However, information on the current levels and associated ecological risks of e-waste-derived contaminants such as polychlorinated biphenyls (PCBs) in e-waste site is limited. Wild fish, because they can accumulate high pollutant levels, are suitable indicators for environmental pollution monitoring and has been widely employed as biomonitoring. In this study, we investigated the changes in the levels and profiles of PCBs in a wild fish species, the northern snakehead (Channa argus), before (2009) and after (2016) the ban of crude e-waste recycling from a typical e-waste recycling site in South China. The mean total PCB concentration in the northern snakehead sampled in 2016 (343 ng/g ww) declined by 75% compared with that (1410 ng/g ww) in 2009. The contributions of less chlorinated congeners (tri-CBs and tetra-CBs) in the northern snakehead tended to decrease over the years, indicating that the lighter congeners are more easily eliminated than the heavier ones in the environment. Our findings suggested no fresh PCB input in these years, as well as the positive impacts of laws and regulations on the prohibition of e-waste recycling. The ecological risk assessment suggested that PCB exposure may have median to high risks to the wild fish and fish-eating wildlife that inhabit the e-waste site, even after the ban of crude e-waste recycling activities.

Toxic chemicals from uncontrolled e-waste recycling: Exposure, body burden, health impact

Uncontrolled electronic-waste (e-waste) recycling processes have induced serious environmental pollution and human health impacts. This paper reviewed studies on the wide range of toxic chemicals through the use of primitive recycling techniques, their transfer to various ecological compartments, and subsequent health impacts. Results indicated that local food items were heavily polluted by the pollutants emitted, notably heavy metals in vegetables, rice, fish and seafood, and persistent organic pollutants (POPs) in livestock. Dietary exposure is the most important exposure pathway. The associations between exposure to e-waste and high body burdens of these pollutants were evident. It seems apparent that toxic chemicals emitted from e-waste activities are causing a number of major illnesses related to cardiovascular, digestive and respiratory systems, according to the information provided by a local hospital (Taizhou, an e-waste recycling hot spot in China). More epidemiological data should be made available to the general public. It is envisaged that there are potential dangers of toxic chemicals passing on to the next generation via placental transfer and lactation. There is a need to monitor the development and health impacts of infants and children, born and brought up in the e-waste sites.

Forty years studies on polychlorinated biphenyls pollution, food safety, health risk, and human health in an e-waste recycling area from Taizhou city, China: a review

E-waste generation has become a serious environmental challenge worldwide. Taizhou of Zhejiang Province, situated on the southeast coastline of China, has been one of the major e-waste dismantling areas in China for the last 40 years. In this review, we focused on the polychlorinated biphenyl (PCB) trends in environmental compartments, burden and impact to humans, food safety, and health risk assessment from Taizhou, China. The review suggested that PCBs showed dynamic trends in air, soil, water, biodiversity, and sediments. Soils and fish samples indicated higher levels of PCBs than sediments, air, water, and food items. PCB levels decreased in soils with the passage of time. Agriculture soils near the e-waste recycling sites showed more levels of total PCBs than industrial soils and urban soils. Dioxin-like PCB levels were higher in humans near Taizhou, suggesting that e-waste pollution could influence humans. Compared with large-scale plants, simple household workshops contributed more pollution of PCBs to the environment. Pollution index, hazard quotient, and daily intake were higher for PCBs, suggesting Taizhou should be given priority to manage the e-waste pollution. The elevated body burden may have health implications for the next generation. The areas with stricter control measures, strengthened laws and regulations, and more environmentally friendly techniques indicated reduced levels of PCBs. For environment protection and health safety, proper e-waste dismantling techniques, environmentally sound management, awareness, and regular monitoring are very important.

Measurement of polychlorinated biphenyls with hand wipes and matched serum collected from Chinese E-waste dismantling workers: Exposure estimates and implications

To date, dermal/hand-to-mouth exposure to chemicals in the e-waste recycling environment has not been sufficiently understood, and the importance of dermal absorption of chemicals in e-waste dismantling workers remains controversial. In this study, we utilized hand wipes and matched sera to characterize dermal/hand-to-mouth exposure to PCBs for e-waste dismantling workers, and potential effects on thyroid hormones were also assessed. PCB loadings in hand wipes varied from 0.829-265 ng wipe^-1 (11.3-2850 ng m^-2 wipe^-1), with 37.2 ng wipe^-1 (432 ng m^-2 wipe^-1) as the median value. Serum concentrations of PCBs ranged from 32.3-3410 ng g^-1 lipid weight (lw) with 364 ng g^-1 lw as the median value. Between wipes and sera, lower-chlorinated congeners (e.g. CB-28, -66, -74, -99,-105 and -118) showed significant associations (p < 0.01), but higher-chlorinated congeners (e.g. CB-138, -153, -156, -170, and -180) did not. These lower-chlorinated CBs were the major contributors to estimated dermal/hand-to-mouth average daily doses (ADDs) and the hazard index (HI). Correspondingly, their estimated contributions to serum levels by dermal absorption were also significant, with the contribution of CB-28 being as high as 21.4%. As a consequence, dermal absorption of some low-chlorinated congeners was a non-negligible route for e-waste dismantling workers. Although insignificant association was shown between serum PCBs and thyroid hormones, the potential health risk should be of concern due to the high levels of PCBs observed in workers' sera.

Endocrine-disrupting organochlorine xenobiotics in fish products imported from Asia-an assessment of human health risk

The sources of endocrine-disrupting persistent organochlorine compounds (OC) are environmental pollutants. Contaminated food is a direct result of environmental pollution, and fish are considered as the main source of OC in the human diet. This study aimed to analyze the contamination of imported fish fillets with organochlorine pesticides (OCPs) and polychlorinated biphenyl (PCB) congeners in the context of potential health risks of consumers in Poland in the light of the new tolerable weekly intake (TWI) values. The tested compounds in fish products were determined by liquid-liquid extraction and gas chromatography mass spectrometry (GS-MS) method. Despite the detection of almost all pesticides analyzed in the fish fillets tested, the risk factor (hazard quotient) was significantly lower than 1.0, ranging from 0.003 to 0.013. Considering the previous recommended TWI value (14 pg-TEQ/kg bw/week), the estimated weekly intake was lower at 43-53% of TWI. However, according to the new TWI values set by the EFSA in 2018, the estimated weekly intake was about three times higher than the TWI. This raises concerns regarding threats to consumer health.

Proteomic insight on the polychlorinated biphenyl degrading mechanism of Pleurotus pulmonarius LBM 105

White-rot fungi are well known bioremediation agents capable of removing recalcitrant xenobiotics. However, the molecular mechanism involved in this process is not well understood. The aim of the present study was to compare the proteomic profiles of Pleurotus pulmonarius LBM 105 in presence and absence of a mixture of polychlorinated biphenyls. Cultures of the fungus were spiked with a mixture of Aroclors and cultivated for 28 days. This strain achieved a peak of PCBs-removal of 65.50 ± 8.09% after 21 days. The ecotoxicological assays showed a toxicity reduction of 46.47%. Based on these findings, a proteomic study was carried out and it was proven that the oxidative metabolism was highly affected. Two proteins that have a function at the transcriptional level and related to the oxidative metabolism, the glyceraldehyde-3-phosphate dehydrogenase and the basal transcription factor 3, presented an increase in their quantity in PCBs presence. Several oxidases and reductases were highly induced, presenting the short chain reductases, aldo/keto reductases, laccases and versatile peroxidases as the enzymes with the most notorious changes. These results indicate a complex response of the fungal metabolism towards these pollutants, which includes a transcriptional response to the oxidative stress and a modification of the intra- and extra-cellular enzymatic profile.

Transfer of dechlorane plus between human breast milk and adipose tissue and comparison with legacy lipophilic compounds

In this study, levels of dechlorane plus (DP) in breast milk and matched adipose tissue samples were measured from 54 women living in Wenling, China. Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured simultaneously for comparison. The levels of ∑DPs/∑PBDEs varied from less than one to several dozens of ng g^-1 lipid weight (lw) in matrices and the levels of ∑PCBs varied between several to hundreds of ng g^-1 lw. In the same matrix, ∑DPs and ∑PCBs/∑PBDEs showed a significant relationship (p < 0.05), indicating that they shared common sources. Accordingly, there was a strong association of lipid-adjusted concentrations of individual compounds (BDE-209 excluded) between matrices (p < 0.001), suggesting that breast milk could be a proxy for adipose tissue in human bioburden monitoring of these compounds. The predicted lipid-adjusted milk/adipose ratios varied from 0.62 to 1.5 but showed significant differences (p<0.001) between compounds, suggesting a compound-specific transfer between milk lipids and adipose tissue lipids. Specifically, the milk/adipose ratios for syn-DP and anti-DP (-1.40 and 1.3, respectively) were significantly higher than those of CB congeners and hexa/hepta-BDE congeners (p < 0.05). In addition, unlike PCBs/PBDEs (excluding BDE-209), DP's hydrophobicity might not be responsible for its preferable distribution in milk lipids. Instead, the interaction with nonlipid factors played a key role. The fraction of anti-DP between the two kinds of matrices was not significantly different, suggesting that the biochemical transfer processes may not be efficient enough to distinguish DP isomers. Nevertheless, the congener patterns of PCBs/PBDEs gave a clue about the compound-specific transfer between milk and adipose tissue. To our knowledge, this is the first to report the relationships of DP between adipose tissue and breast milk. These results could provide useful and in-depth information on biomonitoring of DP and facilitate the understanding of the accumulation and excretion potentials of DP and its distribution-related mechanism in humans.

Polychlorinated biphenyls in the soil-crop-atmosphere system in e-waste dismantling areas in Taizhou: Concentrations, congener profiles, uptake, and translocation

Samples of soil, air, and locally grown crops from around an old e-waste dismantling area (Fengjiang) and a new e-waste dismantling area (Binhai) in Taizhou were analyzed to investigate the behavior of polychlorinated biphenyls (PCBs) released during e-waste dismantling in the soil-crop-atmosphere system. The results indicated that PCB pollution is still widespread in the study area. The PCB concentrations were clearly higher in soil from FJ than in soil from BH, and the concentrations in the functional zones decreased strongly in the order industry park > residential area > farmland. Historical and current emissions during e-waste dismantling processes are probably the main sources of PCBs to soil because PCB production and use are banned. The long half-lives of PCBs have caused the target congener concentrations in soil not to decrease markedly over 10 years. The "halo effect" may have caused PCBs in soil in the heavily polluted FJ area to diffuse into the surrounding area. Soil-air exchange of PCBs in heavily contaminated FJ area may supply PCBs to air because the temperatures in Taizhou are often high. PCBs can accumulate in crops through various pathways. Less-chlorinated PCBs (mainly including Tri-PCBs) can enter crops by root uptake and translocated to the aerial tissues, and more-chlorinated PCBs (including Penta-PCBs and Hexa-PCBs) at high concentrations in soil can enter underground crop tissues through passive transport. More-chlorinated PCBs in underground tissues cannot be transferred to aboveground tissues of tall crops but may be transferred to aboveground tissues of short crops through the root-to-stem pathway and through soil dust being transferred to aboveground external surfaces.

Transcriptome analysis in normal human liver cells exposed to 2, 3, 3', 4, 4', 5 - Hexachlorobiphenyl (PCB 156)

BACKGROUNDS

Polychlorinated biphenyls are persistent environmental pollutants associated with the onset of non-alcoholic fatty liver disease in humans, but there is limited information on the underlying mechanism. In the present study, we investigated the alterations in gene expression profiles in normal human liver cells L-02 following exposure to 2, 3, 3', 4, 4', 5 - hexachlorobiphenyl (PCB 156), a potent compound that may induce non-alcoholic fatty liver disease.

METHODS

The L-02 cells were exposed to PCB 156 for 72 h and the contents of intracellular triacylglyceride and total cholesterol were subsequently measured. Microarray analysis of mRNAs and long non-coding RNAs (lncRNAs) in the cells was also performed after 3.4 μM PCB 156 treatment.

RESULTS

Exposure to PCB 156 (3.4 μM, 72 h) resulted in significant increases of triacylglyceride and total cholesterol concentrations in L-02 cells. Microarray analysis identified 222 differentially expressed mRNAs and 628 differentially expressed lncRNAs. Gene Ontology and pathway analyses associated the differentially expressed mRNAs with metabolic and inflammatory processes. Moreover, lncRNA-mRNA co-expression network revealed 36 network pairs comprising 10 differentially expressed mRNAs and 34 dysregulated lncRNAs. The results of bioinformatics analysis further indicated that dysregulated lncRNA NONHSAT174696, lncRNA NONHSAT179219, and lncRNA NONHSAT161887, as the regulators of EDAR, CYP1B1, and ALDH3A1 respectively, played an important role in the PCB 156-induced lipid metabolism disorder.

CONCLUSION

Our findings provide an overview of differentially expressed mRNAs and lncRNAs in L-02 cells exposed to PCB 156, and contribute to the field of polychlorinated biphenyl-induced non-alcoholic fatty liver disease.

Polychlorinated biphenyls and their hydroxylated metabolites in the serum of e-waste dismantling workers from eastern China

A number of studies have reported on the exposure of e-waste dismantling workers to significantly high concentrations of halogenated organic pollutants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers. Such exposure can have adverse health effects. However, little information on the metabolites of these contaminants exists. In this study, we investigated PCBs levels and their hydroxylated metabolites (OH-PCB) in the serum of e-waste workers in Taizhou in eastern China. Our results indicate elevated PCB and OH-PCB levels in the serum of the workers, with medians of 443.7 and 133.9 ng/g lw, respectively. Tri- to hexachlorinated PCB congeners were the dominant homologue groups in all of the samples. 4-OH-CB107 was the predominant homologue among the hydroxylated metabolites, accounting for 88.9% of the total OH-PCB concentrations. While dietary sources (e.g., fish) appear to be an important route for PCB accumulation in non-occupational exposure groups, exposure via ingestion of house dust and inhalation of pollutants derived from the recycling of PCB-containing e-wastes may primarily contribute to the high body burden observed in the occupational groups. Since we found concentrations of metabolites higher than those of their parent compounds, further studies need to pay more attention to their bioaccumulation and toxicity.

Prenatal exposure to polychlorinated biphenyl and umbilical cord hormones and birth outcomes in an island population

Prenatal exposure to polychlorinated biphenyl (PCB) is suspected to interfere with fetal development including reproductive and thyroid function and birth outcomes, but published evidence are still sparse. We designed a cross-sectional study to analyze the associations between PCB levels in umbilical cord sera and hormones and birth outcomes of mothers and newborns who are residents from an island. Seven indicator-PCB (PCB-28, 52, 101, 118, 138, 153, 180), and five reproductive hormones including luteotropic hormones (LH), estradiol (E2), testosterone (T), follicle-stimulating hormones (FSH) and anti-Mullerian hormones (AMH), and three thyroid hormones including tri-iodothyronine (T3), tetra-iodothyronine (T4) and thyroid stimulating hormones (TSH) were measured in 106 cord sera specimens. Birth outcomes include birth weight, length, head circumference, and gestational age. Multiple linear regression and quartile regression were used to analyze the associations between PCB and each of the hormones and birth outcomes, adjusting for selected potential confounders. The median value of total PCB in umbilical cord sera was 2.02 μg L^-1 (IQR, 1.13-4.64). Several negative associations between PCB exposure and reproductive hormones were found. Among them, the β value of PCB-101 for FSH reached -0.38 (95%CI, -0.69, -0.07; p = 0.02). Moreover, we also found some sex-specific associations i.e. PCB-28 was negatively correlated with LH and T and PCB-118 was negatively correlated with T in male newborns but not in female newborns. The associations between PCB and birth outcomes seem to differ by molecular weight of the PCB congeners i.e. the low-chlorinated PCB congeners were negatively associated with gestational age and head circumference while high-chlorinated PCB congeners were positively associated birth weight and gestational age. In this study, we found that PCB congeners with different molecular weight has different associations with hormones and birth outcomes, and future studies are recommended to investigate underlying mechanisms of these associations.

Intake, distribution, and metabolism of decabromodiphenyl ether and its main metabolites in chickens and implications for human dietary exposure

Diet is considered as the most important human exposure pathway for polybrominated diphenyl ethers (PBDEs). Metabolism and accumulation patterns of PBDEs in different growth periods of chickens are helpful for evaluating human dietary exposure, but such information is scarce. In this study, female chickens were fed with food spiked with BDE-209 at 85 mg kg^-1, and the intake, accumulation, and excretion of BDE-209 and its main metabolites in various tissues were examined. Concentrations of BDE-209 in chicken tissues increased over time in a tissue-specific manner; they were the greatest in liver and generally the lowest in breast meat during the entire exposure period. The kinetic patterns were dependent on both growth-dilution effects and accumulated concentrations of BDE-209. Tissue concentrations of ∑₈PBDE (sum of BDE-28, 47, 99, 100, 153, 154, 183, and 209) followed the sequence of liver > blood > skin > intestine > stomach > leg meat > breast meat. Different tissue partition coefficients and perfusion rates for blood may have resulted in different PBDE concentrations in tissues. The absorption efficiency of BDE-209 in chicken tissues followed the sequence of liver (0.15 ± 0.032%) > skin (0.14 ± 0.038%) > intestine (0.071 ± 0.021%) > breast meat (0.062 ± 0.020%) > leg meat (0.059 ± 0.016%) > stomach (0.021 ± 0.0095%), likely due in part to facilitated absorption of BDE-209 by transport proteins (P-glycoproteins). On average, 9.3 ± 1.7% of BDE-209 was excreted in feces. Estimated human average dietary intake via the consumption of chicken tissues of ∑₈PBDE for adults and children was 319 and 1380 ng day^-1 for liver, 211 and 632 ng day^-1 for leg meat, and 104 and 311 ng day^-1 for breast meat from the contaminated group. Liver clearly poses the highest exposure risk for human consumption, particularly if chickens are fed with contaminated feed.

Rhizoremediation of a dioxin-like PCB polluted soil by alfalfa: Dynamic characterization at temporal and spatial scale

This study investigates the temporal and spacial dissipation dynamics of a dioxin-like polychlorinated biphenyl (PCB 77) in the rhizosphere of alfalfa. A three-chamber rhizobox was designed to compare the PCB 77 dissipation efficiency in the rhizosphere, near-rhizosphere, and far-rhizosphere zones. Culture-independent techniques, including quantitative PCR (qPCR), Biolog-ECO plate, and denatured gradient gel electrophoresis (DGGE) were employed to investigate the variation of bacterial quantity, metabolic diversity and community structure in the alfalfa-rhizobium symbiosis rhizosphere at different rhizoremediation stages. PCB dissipation rates in different rhizosphere zones were in the order: rhizosphere (90.9%) > near-rhizosphere (80.5%) > far-rhizosphere (31.7%). The number of the bacterial 16S rRNA gene copies in the rhizosphere zone in the polluted treatment reached the highest value of all the treatments. Microbial metabolic diversity, as indicated by average well color development (AWCD) in both rhizosphere and near-rhizosphere zones, had recovered from the PCB 77 pollution. The soil bacterial community diversity improved greatly in the rhizosphere of alfalfa, with some new species appeared in the rhizosphere and near-rhizosphere zones. In conclusion, the dissipation of PCB 77, the quantity of total soil bacteria, soil microbial metabolic diversity, and soil microbial community structure were significantly improved in rhizosphere and near-rhizosphere zones of alfalfa.

Long-term spatiotemporal trends and health risk assessment of oyster arsenic levels in coastal waters of northern South China Sea

Long-term spatiotemporal trends and health risk assessment of oyster arsenic levels in the coastal waters of northern South China Sea were investigated in order to help improve the quality and safety control and sustainable aquaculture for mollusks in China. Cultured oysters (Crassostrea rivularis) collected from the waters of 23 bays, harbors, and estuaries along the coast of northern South China Sea from 1989 to 2012 were examined for spatial patterns and long-term temporal trends of oyster arsenic levels. Single-factor index and health risk assessment were used to quantify arsenic exposure to human health through oyster consumption. Overall, arsenic was detected in 97.4% of the oyster samples, and oyster arsenic levels were non-detectable-2.51 mg/kg with an average of 0.63 ± 0.54 mg/kg. Oyster arsenic levels in the coastal waters of northern South China Sea showed an overall decline from 1989 to 2012, remained relatively low since 2005, and slightly increased after 2007. Oyster arsenic levels in Guangdong coastal waters were much higher with more variation than in Guangxi and Hainan coastal waters, and the long-term trends of oyster arsenic levels in Guangdong coastal waters dominated the overall trends of oyster arsenic levels in the coastal waters of northern South China Sea. Within Guangdong Province, oyster arsenic levels were highest in east Guangdong coastal waters, followed by the Pearl River estuary and west Guangdong coastal waters. Single-factor index ranged between 0.27 and 0.97, and average health risk coefficient was 3.85 × 10^-5, both suggesting that oyster arsenic levels in northern South China Sea are within the safe range for human consumption. However, long-term attention should be given to seafood market monitoring in China and the risk of arsenic exposure to human health through oyster consumption.

A pilot study on health risk assessment based on body loadings of PCBs of lactating mothers at Taizhou, China, the world's major site for recycling transformers

Our early study reported an extraordinarily high Estimated Daily Intake (EDI) of PCBs of lactating mothers from Taizhou, Zhejiang Province, China (based on a food consumption survey and food basket analysis). The EDI well exceeded the intake limit stipulated by FAO/WHO 70 pg TEQ/kg body weight (bw)/month. The present pilot study provided further information on PCBs body burden in lactating mothers of Taizhou. The total PCBs detected in human milk, placenta and hair samples of these lactating mothers were 363 ng/g lipid, 224 ng/g lipid, and 386 ng/g dry wt. Respectively, three times higher than those samples collected from the reference site (Lin'an). Compared with the previous reported values in the 3rd WHO coordinated study, Taizhou topped the list of 32 countries/regions with regards to WHO-PCB-TEQ values of milk samples, which could be attributed to the relatively higher level of PCB-126 derived from electronic waste. In addition, the corresponding EDI of PCBs of Taizhou mothers (12.9 pg WHO-PCB-TEQ/kg bw/day) and infants (438 pg WHO-PCB-TEQ/kg) were derived from individual congener levels in human milk. The results were also higher than the tolerable daily intakes recommended by WHO (1-4 pg WHO-TEQ/kg bw/day) by 3 and 110 times, for mothers and infants, respectively. A more intensive epidemiological study on the potential health effects of e-waste recycling activities affecting both workers and residents seems to be of top priority, based on findings of this pilot study.

Accumulation of polybrominated diphenyl ethers in breast milk of women from an e-waste recycling center in China

Polybrominated diphenyl ethers (PBDEs) can be transferred to infants through the ingestion of breast milk, resulting in potential health risk. In this study, PBDEs, hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and 2,2',4,4',5,6'-hexachlorobiphenyl (CB-153) in human milk from women living adjacent to e-waste recycling sites of Wenling, China, were investigated. The median level of PBDEs in samples from residents living in the e-waste recycling environment >20years (R₂₀ group, 19.5ng/g lipid weight (lw)) was significantly higher than that for residents living in Wenling <3years (R₃ group, 3.88ng/g lw) (p<0.05), likely ascribable to specific exposure to PBDEs from e-waste recycling activities. In the R₂₀ group, most congeners (except for BDE-209) were correlated with each other (p<0.05). Moreover, CB-153 showed significant association with most PBDE congeners, rather than BDE-209. The relationship indicated that most BDE congeners other than BDE-209 shared common sources and/or pathways with CB-153, e.g., dietary ingestion. The correlations between BDE-209 and other congeners were different in the two groups, likely suggesting their different exposure sources and/or pathways for PBDEs. Although estimated dietary intake of PBDEs for infants via breast milk was lower than the minimum value affecting human health, the PBDE exposure of infants should be of great concern because of their potential effect on the development of neonates over long-term exposure. OH-PBDEs were not detected in the collected samples, which is in accordance with reports in published literature, likely indicating that they were not apt to be accumulated in human milk.

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in Zhejiang foods (2006-2015): Market basket and polluted areas

In this study, we measured the levels of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in 620 foods collected during 2006-2015 from Zhejiang market, a municipal waste incinerator (MWI) and E-waste disassembling areas. For market retail foods, the levels of PCDD/F TEQs, PCDD/F plus dioxin-like PCB (DL-PCB) TEQs, and the concentrations of six indicator PCBs were generally below the EU ML. The average TEQ values for the 13 food groups were 42% of EU ML for PCDD/Fs and 32% for PCDD/Fs+DL-PCBs. Some foods of animal origin were close to the corresponding EU ML: pork (PCDD/F TEQ, 79% of ML; PCDD/F+DL-PCB TEQ, 84% of ML); infant formula (90% of PCDD/F ML) and beef (96% of PCDD/F ML; PCDD/F+DL-PCB TEQ, 78% of ML). The estimated dietary intake for the general population was 22.0pgTEQ(kgbody weight (bw))^-1month^-1, which was below the standard of 70pgTEQ(kgbw)^-1month^-1 set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). For the MWI and E-waste disassembling sites, high concentrations of PCDD/Fs and PCBs were measured in all foods tested. The corresponding TEQ in (1) freshwater fish, (2) chicken egg, (3) chicken meat and (4) chicken liver was (1) 1.4-fold (MWI, PCDD/F TEQ), (2) 11.2-fold (MWI,) and 1.6-fold (E-waste disassembling sites), (3) 20.7-fold and (4) 3.3-fold greater than EU ML, respectively. Considering the worst situation (highly polluted foods were consumed), the estimated dietary intake for local residents were 244 (MWI) and 240pgTEQ(kgbw)^-1month^-1 (E-waste disassembling sites), approximately 3.5-fold greater compared to the standard 70pgTEQ(kgbw)^-1month^-1 set by JECFA, indicating high risk could have been imposed on the health of local residents.

The formal electronic recycling industry: Challenges and opportunities in occupational and environmental health research

BACKGROUND

E-waste includes electrical and electronic equipment discarded as waste without intent of reuse. Informal e-waste recycling, typically done in smaller, unorganized businesses, can expose workers and communities to serious chemical health hazards. It is unclear if formalization into larger, better-controlled electronics recycling (e-recycling) facilities solves environmental and occupational health problems.

OBJECTIVES

To systematically review the literature on occupational and environmental health hazards of formal e-recycling facilities and discuss challenges and opportunities to strengthen research in this area.

METHODS

We identified 37 publications from 4 electronic databases (PubMed, Web of Science, Environmental Index, NIOSHTIC-2) specific to chemical exposures in formal e-recycling facilities.

DISCUSSION

Environmental and occupational exposures depend on the degree of formalization of the facilities but further reduction is needed. Reported worker exposures to metals were often higher than recommended occupational guidelines. Levels of brominated flame-retardants in worker's inhaled air and biological samples were higher than those from reference groups. Air, dust, and soil concentrations of metals, brominated flame-retardants, dioxins, furans, polycyclic-aromatic hydrocarbons, or polychlorinated biphenyls found inside or near the facilities were generally higher than reference locations, suggesting transport into the environment. Children of a recycler had blood lead levels higher than public health recommended guidelines.

CONCLUSIONS

With mounting e-waste, more workers, their family members, and communities could experience unhealthful exposures to metals and other chemicals. We identified research needs to further assess exposures, health, and improve controls. The long-term solution is manufacturing of electronics without harmful substances and easy-to-disassemble components.

Spatial-temporal trend and health implications of polycyclic aromatic hydrocarbons (PAHs) in resident oysters, South China Sea: A case study of Eastern Guangdong coast

Spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) were investigated in Eastern Guangdong coast, China. Total PAH concentrations in oysters ranged from 231 to 1178ng/g with a mean concentration of 622ng/g dry weight. Compared with other bays and estuaries, PAH levels in oysters were moderate. Spatial distribution of PAHs was site specific, with relatively high PAH concentrations observed in Zhelin Bay and Kaozhouyang Bay. Based on the Spearman test analysis, only PAH concentration in oysters from Jiazi Harbor showed a significant increasing trend (P<0.05). Three-ring PAHs were the most abundant, accounting for 54.2%-88.4% of total PAHs. Diagnostic ratios suggested that PAHs were derived mainly from petroleum origin. BaP and ∑4PAH concentrations were well within the European Union limits (5ng/g and 30ng/g wet weight, respectively). The incremental lifetime cancer risks (ILCR) for PAHs were <10(-5), indicating that the adverse health risks associated with oyster consumption in this area were minimal.

Polychlorinated biphenyl (PCBs) in rice grains and straw; risk surveillance, congener specific analysis, distribution and source apportionment from selected districts of Punjab Province, Pakistan

The current study presents health risk surveillance by investigating the levels of polychlorinated biphenyls (PCBs) in rice (Oryza sativa L.) grains and rice straw. Samples were collected from four districts (Okara, Sahiwal, Lahore and Sheikhpura) of Punjab Province, Pakistan for congener specific analysis of PCBs, and to observe the spatial distribution pattern and point sources. Level of Σ30 PCB (ng g(-1)) in rice grains and rice straw ranged from 4.31 to 29.68 and 6.11-25.35, respectively. Tetra-CBs were found predominant in rice straw (49%) and grains (38%) over other PCB homologs. No significant variation (P>0.005) was observed for most of the screened PCBs congeners except, PCB-66, -77, -60, -101, -74, -138, -153 and -105 in rice grains and PCB-66 in rice straw. Reported toxicity equivalency (TEQ) values for dioxin like PCBs in rice grains were found lower than the previously published reports from Asian countries, however higher TEQ values are reported for rice straw in this study. Health was found at risk of cancer among one in million by consumption of the study area food stuffs, though no considerable carcinogenic risks to human health was found.

Assessment of the Polychlorinated Biphenyl (PCB) Occurrence in Copper Sulfates and the Influential Role of PCB Levels on Grapes

Copper sulfates (CuSO₄) are widely used as the primary component of fungicides in the grape industry. The agricultural-grade CuSO₄ that we collected from Chinese nationwide markets were found to be contaminated by polychlorinated dibenzo-p-dioxins and dibenzofurans and high levels of polychlorinated biphenyls (Σ₁₉PCBs: 0.32~9.51 ng/g). In the following research, we studied the impact of CuSO₄ application on PCB levels in grape products through a field experiment, and conducted a national survey to speculate the role that CuSO₄ played on the occurrence of PCB in grapes. In the field experiment, an obvious increase of PCBs in grape leaves (from 174 to 250 pg/g fw) was observed after Bordeaux mixture (the main component of which is CuSO₄) application. As to the main PCB congener in CuSO₄, the most toxic CB 126 (toxic equivalency factor = 0.1) also increased in grape peels (from 1.66 to 2.93 pg/g fw) after pesticide spray. Both the correlation study and the principal component analysis indicated that environmental factors were dominant PCB contributors to grapes, and grapes from e-waste dismantling area containing the highest PCBs also proved the notion. It is worth noting that this report describes the first research examining PCBs in CuSO₄ and its influence on agricultural products to date.

Dietary exposure to non-dioxin-like PCBs of different population groups in Austria

The dietary exposure to the sum of the six indicator PCBs (Σ6 PCBs; PCB 28, 52, 101, 138, 153, and 180) across different Austrian population groups was assessed in this study by combining data on occurrence from food of the Austrian market (n=157) analysed during 2006-2011 with national food consumption data. The most contaminated food group was meat, poultry, game and offal with average levels of ndl-PCBs of 5.20 ng g(-1) fat. In fish and fish products and eggs, mean concentrations of 3.89 ng g(-1) fresh weight (fw) and 4.00 ng g(-1) fat, respectively, were found. In milk and dairy products average concentrations ranged from 3.07 to 4.44 ng g(-1) fat. The mean dietary intake of Σ6 PCBs was estimated to be 3.37 ng kg(-1) bw d(-1) for children (6-15 years old), 3.19 ng kg(-1) bw d(-1) for women (19-65 years) and 2.64 ng kg(-1) bw d(-1) for men (19-65 years). In all three population groups, milk and dairy products was the major contributing food group to the total dietary intake (50-55%) followed by fish and fish products (23-27%). The exposure of all Austrian population groups is well below the tolerable daily intake (TDI) of 10 ng kg(-1) bw d(-1) proposed by WHO, accounting for 34% in children, 32% in women and 26% in men.

Polychlorinated biphenyls and polybrominated biphenyl ethers in adipose tissue and matched serum from an E-waste recycling area (Wenling, China)

To Date, the knowledge on relationship between PCBs/PBDEs exposure and thyroid hormones (THs) levels during pregnancy still needs to be extended. Meanwhile, studies on congener-specific adipose-serum ratios for PCBs/PBDEs were limited. This study reports the levels of PCBs/PBDEs in serum-adipose tissue samples (n = 64) from expectant women living surrounding e-waste recycling sites in Wenling, China. Their concentrations varied from several to hundreds of ng g(-1) lipid. Maternal exposure to PCBs was associated with lower TSH during pregnancy, suggesting possible implication for maternal health and fetal development. The compound levels between the adipose tissue and matched serum samples were highly correlated (p < 0.001), generating a predicted adipose-serum partitioning relationship for individual PCB congener and PBDE congener. Molecular characteristics, such as Kow value, molecular weight and molecular volume, may play a key role in the variable partitioning of some compounds between serum and adipose tissue.

Human health risk assessment of multiple contaminants due to consumption of animal-based foods available in the markets of Shanghai, China

To assess the health risks due to food consumption, the human daily intake and uptake of organochlorine pesticides, polychlorinated biphenyls, polybrominated diphenyl ethers, polycyclic aromatic hydrocarbons, and toxic trace elements (mercury, chromium, cadmium, lead, and arsenic) were estimated based on the animal-based foods collected from markets in Shanghai, China. The estimated daily intake and uptake considering the contaminant bioaccessibility via single food consumption were 9.4-399 and 4.2-282 ng/kg body weight/day for adults, and 10.8-458 and 4.8-323 ng/kg body weight/day for children, respectively. These values were 0.2-104 and 0.05-58.1, and 0.2-119 and 0.06-66.6 ng/kg body weight/day via multiple food consumption for adults and children, respectively. According to the United States Environmental Protection Agency risk assessment method, the non-cancer and cancer health risks posed by the contaminants were estimated using the hazard quotient and the lifetime cancer risk method, respectively. The results showed that the combined hazard quotient values for multiple contaminants via single or multiple food consumption were below 1, suggesting that the residents in Shanghai would not experience a significant non-cancer health risk. Among the contaminants investigated, the potential non-cancer risk of methylmercury was highest. However, the combined cancer risk posed by multiple contaminants in most foods exceeded the accepted risk level of 10(-6), and inorganic arsenic was the main contributor. The risks caused by polybrominated diphenyl ethers for cancer and non-cancer effects were negligible. The cancer risk of inorganic arsenic is a matter of concern in animal-based foods from Shanghai markets.

Human dietary intake of organohalogen contaminants at e-waste recycling sites in Eastern China

This study reports concentrations and human dietary intake of hexabromocyclododecanes (HBCDs), polychlorinated biphenyls (PCBs) as well as selected "novel" brominated flame retardants (NBFRs) and organochlorine pesticides, in ten staple food categories. Samples were sourced from areas in Taizhou City, eastern China, where rudimentary recycling and disposal of e-waste is commonplace, as well as from nearby non-e-waste impacted control areas. In most instances, concentrations in foods from e-waste recycling areas exceeded those from control locations. Concentrations of 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) and bis-(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (BEH-TBP) in samples from e-waste sites were 3.09-62.2ng/g and 0.81-16.3ng/g lipid weight (lw), respectively; exceeding consistently those in foods acquired from control sites by an order of magnitude in many cases. In contrast, while concentrations of HBCD in some foods from e-waste impacted areas exceed those from control locations; concentrations in pork, shrimp, and duck liver are higher in control samples. This highlights the potential significance of non-e-waste sources of HBCD (e.g. building insulation foam) in our study areas. While concentrations of DDT in all foods examined except pork were higher in e-waste impacted samples than controls; our exposure estimates were well below the provisional tolerable daily intake of 0.01mg/kgbw/day derived by the Joint FAO/WHO Meeting on Pesticide Residues. Concentrations of ΣPCBs resulted in exposures (650 and 2340ng/kgbw/day for adults and children respectively) that exceed substantially the Minimal Risk Levels (MRLs) for ΣPCBs of 20ng/kgbw/day derived by the Agency for Toxic Substances & Disease Registry. Moreover, when expressed in terms of dioxin-like toxicity equivalency based on the four dioxin-like PCBs monitored in this study (DL-PCBs) (PCB-105, 118, 156, and 167); concentrations in e-waste impacted foods exceed limits set by the European Union in 6 of the 8 food groups studied and result in dietary exposures for children (10.2pgTEQ/kgbw/day) that exceed the WHO tolerable daily intake of 1-4pgTEQ/kgbw/day.

Autochthonous ascomycetes in depollution of polychlorinated biphenyls contaminated soil and sediment

We investigated the capacity of a consortium of ascomycetous strains, Doratomyces nanus, Doratomyces purpureofuscus, Doratomyces verrucisporus, Myceliophthora thermophila, Phoma eupyrena and Thermoascus crustaceus in the mycoremediation of historically contaminated soil and sediment by polychlorinated biphenyls (PCBs). Analyses of 15 PCB concentrations in three mesocosms containing soil from which the fungal strains had previously been isolated, revealed significant PCB depletions of 16.9% for the 6 indicator PCBs (i-PCBs) and 18.7% for the total 15 PCBs analyzed after 6months treatment. The degradation rate did not statistically vary whether the soil had been treated with non-inoculated straw or colonized straw or without straw and inoculated with the consortium of the six strains. Concerning the sediment, we evidenced significant depletions of 31.8% for the 6 i-PCBs and 33.3% for the 15 PCB congeners. The PCB depletions affected most of the 15 PCBs analyzed without preference for lower chlorinated congeners. Bioaugmented strains were evidenced in different mesocosms, but their reintroduction, after six months treatment, did not improve the rate of PCB degradation, suggesting that the biodegradation could affect the bioavailable PCB fraction. Our results demonstrate that the ascomycetous strains potentially adapted to PCBs may be propitious to the remediation of PCB contaminated sites.

A systematic review of the human body burden of e-waste exposure in China

As China is one of the countries facing the most serious pollution and human exposure effects of e-waste in the world, much of the population there is exposed to potentially hazardous substances due to informal e-waste recycling processes. This report reviews recent studies on human exposure to e-waste in China, with particular focus on exposure routes (e.g. dietary intake, inhalation, and soil/dust ingestion) and human body burden markers (e.g. placenta, umbilical cord blood, breast milk, blood, hair, and urine) and assesses the evidence for the association between such e-waste exposure and the human body burden in China. The results suggest that residents in the e-waste exposure areas, located mainly in the three traditional e-waste recycling sites (Taizhou, Guiyu, and Qingyuan), are faced with a potential higher daily intake of these pollutants than residents in the control areas, especially via food ingestion. Moreover, pollutants (PBBs, PBDEs, PCBs, PCDD/Fs, and heavy metals) from the e-waste recycling processes were all detectable in the tissue samples at high levels, showing that they had entered residents' bodies through the environment and dietary exposure. Children and neonates are the groups most sensitive to the human body effects of e-waste exposure. We also recorded plausible outcomes associated with exposure to e-waste, including 7 types of human body burden. Although the data suggest that exposure to e-waste is harmful to health, better designed epidemiological investigations in vulnerable populations, especially neonates and children, are needed to confirm these associations.

Paddy field--a natural sequential anaerobic-aerobic bioreactor for polychlorinated biphenyls transformation

The environmental pollution and health risks caused by the improper disposal of electric and electronic waste (e-waste) have become urgent issues for the developing countries. One of the typical pollutants, polychlorinated biphenyls (PCBs), is commonly found in farmland in Taizhou, a major hotspot of e-waste recycling in China. This study investigated the amount of PCB residue in local farmlands. Biotransformation of PCBs was further studied under different water management conditions in paddy field with or without rice cultivation, with a special focus on the alternating flooded and drying processes. It was found that paddy field improved the attenuation of PCBs, especially for highly chlorinated congeners. In the microcosm experiment, 40% or more of the initial total PCBs was removed after sequential flood-drying treatments, compared to less than 10% in the sterilized control and 20% in the constant-drying system. Variation in the quantity of PCBs degrading and dechlorinating bacterial groups were closely related to the alteration of anaerobic-aerobic conditions. These results suggested that alternating anoxic-oxic environment in paddy field led to the sequential aerobic-anaerobic transformation of PCBs, which provided a favorable environment for natural PCB attenuation.

Polycyclic aromatic hydrocarbons and organochlorine pesticides in rice hull from a typical e-waste recycling area in southeast China: temporal trend, source, and exposure assessment

The residue levels of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) and 16 selected organochlorine pesticides (OCPs) in rice and rice hull collected from a typical e-waste recycling area in southeast China were investigated from 2005 to 2007. PAHs and OCPs also were measured in ten mollusk species (soft tissues) collected in an adjacent bay in 2007. Individual PAHs were frequently found in the entire sample set (including the rice, hull, and mollusk samples) with a detection rate of 73 %. The total concentrations of 16 PAHs (ΣPAHs) and 16 OCPs (ΣOCPs) were in the range of 40.8-432 ng/g dry weight (mean: 171 ng/g) and 2.35-925 ng/g (122 ng/g), respectively, which were comparable or higher than those reported in some polluted areas. Statistical comparisons suggested that the concentrations of contaminants in hull gradually decreased from 2005 to 2007 and the residue levels were generally in the order of mollusk, hull, and rice, on a dry weight basis. Principal component analysis in combination with diagnostic ratios implied that combustion of coal, wood, and plastic wastes that are closely associated with crude e-waste recycling activities is the main source of PAHs. The finding of decreasing trend of concentrations of PAHs in this area is consistent with the efforts of local authorities to strengthen regulations on illegal e-waste recycling activities. Composition analysis suggested that there is a recent usage or discharge of hexachlorocyclohexane and dichlorodiphenyltrichloroethane into the tested area. The estimated daily intake (EDI) of ΣPAHs and ΣOCPs (calculated from mean concentrations) through rice and mollusk consumption was 0.411 and 0.921 μg/kg body weight (bw)/day, respectively.

Arsenic concentration in rice, fish, meat and vegetables in Cambodia: a preliminary risk assessment

To assess arsenic contaminations and its possible adverse health effects, food samples were collected from Kandal, Kratie and Kampong Cham in Cambodia. The highest and the lowest concentrations were observed in fish (mean 2,832 ng g(-1), ww) collected from Kandal province and cattle stomach (1.86 ± 1.10 ng g(-1), ww) collected from Kratie, respectively. The daily intake of arsenic via food consumption was 604, 9.70 and 136 μg day(-1) in Kandal, Kratie and Kampong Cham, respectively. The arsenic dietary intake in Kandal ranked No. 1 among all the 17 compared countries or regions. Fish consumption contributed the greatest proportion of total arsenic daily intake in Kandal (about 63.0 %) and Kampong Cham (about 69.8 %). It is revealed to be a much more important exposure pathway than drinking water for residents in Kampong Cham. The results of risk assessment suggested that the residents in Cambodia, particularly for people in Kandal province, suffer high public health risks due to consuming arsenic-contaminated food.

Persistent toxic substances released from uncontrolled e-waste recycling and actions for the future

The Basel Convention on the Control of Transboundary Movement of Hazardous Wastes and their Disposal was adopted on March 22, 1989 and enforced on May 5, 1992. Since then, the USA, one of the world's largest e-waste producers, has not ratified this Convention or the Basel Ban Amendment. Communities are still debating the legal loophole, which permits the export of whole products to other countries provided it is not for recycling. In January 2011, China's WEEE Directive was implemented, providing stricter control over e-waste imports to China, including Hong Kong, while emphasizing that e-waste recycling is the producers' responsibility. China is expected to supersede the USA as the principal e-waste producer, by 2020, according to the UNEP. Uncontrolled e-waste recycling activities generate and release heavy metals and POPs into the environment, which may be re-distributed, bioaccumulated and biomagnified, with potentially adverse human health effects. Greater efforts and scientific approaches are needed for future e-product designs of minimal toxic metal and compound use, reaping greater benefits than debating the definition and handling responsibilities of e-waste recycling.

A review of environmental fate, body burdens, and human health risk assessment of PCDD/Fs at two typical electronic waste recycling sites in China

This paper reviews the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in different environmental media, human body burdens and health risk assessment results at e-waste recycling sites in China. To provide an indication of the seriousness of the pollution levels in the e-waste recycling sites in China, the data are compared with guidelines and available existing data for other areas. The comparison clearly shows that PCDD/Fs derived from the recycling processes lead to serious pollution in different environmental compartments (such as air, soil, sediment, dust and biota) and heavy body burdens. Of all kinds of e-waste recycling operations, open burning of e-waste and acid leaching activities are identified as the major sources of PCDD/Fs. Deriving from the published data, the estimated total exposure doses via dietary intake, inhalation, soil/dust ingestion and dermal contact are calculated for adults, children and breast-fed infants living in two major e-waste processing locations in China. The values ranged from 5.59 to 105.16 pg WHO-TEQ/kg bw/day, exceeding the tolerable daily intakes recommended by the WHO (1-4 pg WHO-TEQ/kg bw/day). Dietary intake is the most important exposure route for infants, children and adults living in these sites, contributing 60-99% of the total intakes. Inhalation is the second major exposure route, accounted for 12-30% of the total exposure doses of children and adults. In order to protect the environment and human health, there is an urgent need to control and monitor the informal e-waste recycling operations. Knowledge gaps, such as comprehensive dietary exposure data, epidemiological and clinical studies, body burdens of infants and children, and kinetics about PCDD/Fs partitions among different human tissues should be addressed.

Dietary exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans via fish consumption and dioxin-like activity in fish determined by H4IIE-luc bioassay

Dietary exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) via fish consumption in two major electronic (e) waste sites: Guiyu (GY), Guangdong Province and Taizhou (TZ), Zhejiang Province, and dioxin-like activity in fish determined by H4IIE-luc bioassay. In the present study, all fish were below EU's maximum allowable concentration in muscle of fish (4 pg WHO-TEQ/g wet wt), except crucian (4.28 pg WHO-TEQ/g wet wt) and silver carps (7.49 pg WHO-TEQ/g wet wt) collected from GY rivers. Moreover, the residual concentration in bighead carp collected from GY (2.15 pg WHO-TEQ/g wet wt) was close to the EU's action level (3 pg WHO-TEQ/g wet wt) which gives "early warning" to the competent authorities and operators to take measures to eliminate contamination. In addition, results indicated that the maximum human intake of PCDD/Fs via freshwater fish consumption in GY was 4.31 pg WHO-TEQ/kg bw/day, which exceeds the higher end of the tolerable daily intake recommended by the WHO, EC-SCF and JECFA (1-4, 2 and 2.3 pg WHO-TEQ/kg bw/day respectively). Furthermore, H4IIE-luc cell bioassay provides a very sensitive and cost-efficient screening tool for assessing the overall dioxin-like toxicity in the study, and is therefore valuable for high-throughput environmental monitoring studies.

Domestic duck eggs: an important pathway of human exposure to PBDEs around e-waste and scrap metal processing areas in Eastern China

Although consumption of local foods is recognized as an important pathway of human exposure to PBDEs in areas of China involved in rudimentary recycling of electronic waste (e-waste), dietary intake studies to date have not considered the contribution from consumption of duck eggs, despite being a common dietary component. Fresh duck eggs (n = 11) were collected from each of five farms located within 500 m of e-waste recycling workshops in the Wenling and Luqiao districts of Taizhou City, Eastern China, in November 2011, along with eggs from a control site located 90 km to the northeast. Average ΣPBDE yolk concentrations in eggs from the Taizhou farms ranged from 52.7 to 1778 ng/g lipid weight (8 ng/g lipid weight at the control site), at the high end of values previously reported for PBDEs in chicken eggs from the same locations and with BDE-209 predominant in over 60% of samples. Estimated typical adult daily ΣPBDE intakes due to consumption of duck eggs were in the range of 159-5124 ng/person per day. For the pentabrominated BDE-99 congener, estimated intakes from duck eggs alone were substantially above the no adverse effect level (NAEL) for impaired human spermatogenesis proposed by Netherlands researchers.

Environmental contamination and human exposure to dioxin-related compounds in e-waste recycling sites of developing countries

E-waste recycling using uncontrolled processes is a major source of dioxin-related compounds (DRCs), including not only the regulated polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) but also non-regulated brominated and mixed halogenated compounds (PBDD/Fs and PXDD/Fs). Various studies at informal e-waste recycling sites (EWRSs) in Asian developing countries found the soil contamination levels of PCDD/Fs from tens to ten thousand picogram TCDD-equivalents (TEQ) per gram and those of DL-PCBs up to hundreds of picogram TEQ per gram. The air concentration of PCDD/Fs was reported as high as 50 pg TEQ per m(3) in Guiyu, the largest Chinese EWRS. Non-regulated compounds also contributed substantially to the total DL toxicity of the DRC mixtures from e-waste, as evidenced by the high TEQ levels estimated for the currently identifiable PBDD/Fs as well as the large portion of unexplained bioassay-derived TEQ levels in soils/dusts from EWRSs. Considering the high exposure levels estimated for EWRS residents, especially children, comprehensive emission inventories of DRCs from informal e-waste recycling, the identities and toxic potencies of unidentified DRCs released, and their impacts on human health need to be investigated in future studies.

OCPs and PCBs in marine edible fish and human health risk assessment in the eastern Guangdong, China

Marine edible fish samples were collected from two important nearshore fishing sites in the eastern Guangdong Province, China: Shantou Harbor and Haimen Bay. In the mixed edible muscle tissues of marine fish samples, the concentrations of polychlorinated biphenyls, dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), chlordanes, and hexachlorobenzene ranged from 1.12 to 53.87, ND (not detected) to 84.01, 0.22 to 7.09, ND to 4.74, and ND to 1.49 ng/g wet weight (ww) in Haimen Bay, respectively, and from ND to 70.35, ND to 164.83, ND to 8.68, ND to 25.61, and ND to 1.76 ng/g ww in Shantou Harbor, respectively. The concentrations of PCBs, DDTs, and HCHs in all samples did not exceed maximum residue limits (China and United States Food and Drug Administration). However, a few fish samples exceed the maximum levels established by the European Union. Daily fish consumption from this region can be of serious concern, and lifetime cancer risk remains a possibility in the studied area.

Potential of autochthonous fungal strains isolated from contaminated soils for degradation of polychlorinated biphenyls

Up to now, most studies on polychlorinated biphenyl (PCB) bioremediation have examined the ability of model fungal strains to biodegrade PCBs. Yet, there is limited information concerning the potential of autochthonous filamentous fungal strains in the biodegradation of PCBs and their possible use in the environmental technologies. In this study, we investigated the capacity of autochthonous fungal strains in the biodegradation of PCBs by isolating 24 taxa from former industrial sites highly contaminated by PCBs. Microscopic and molecular analyses using the internal transcribed spacer (ITS) region revealed that the fungal strains belonged to the phyla Ascomycota (19 strains) and Zygomycota (five strains). The chromatography gas analysis revealed evidence of degradation of seven PCB congeners. With the exception of Circinella muscae which presented no degradation potential, the other fungal strains exhibited a rate of biodegradation ranging from 29 to 85 % after 7 d of incubation in liquid medium. Among these strains, Doratomyces nanus, Doratomyces purpureofuscus, Doratomyces verrucisporus, Myceliophthora thermophila, Phoma eupyrena, and Thermoascus crustaceus showed remarkable degradation ability (>70 %) regardless of the number of chlorine substituents on the biphenyl nucleus and a high tolerance towards PCBs. To our knowledge, this is the first study that demonstrates the ability of PCB degradation by these species and indicates the potential effectiveness of some autochthonous fungal strains in bioremediation systems.

Using placenta to evaluate the polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) exposure of fetus in a region with high prevalence of neural tube defects

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants suspected to have various toxic effects, including reproductive toxicity. The aim of this study was to determine the concentrations of PCBs and PBDEs in human placentas and to examine the potential association between in utero exposure to these pollutants and the risk of neural tube defects. Subjects were recruited from a birth defects surveillance program in a rural area of Shanxi Province, China, from 2005 to 2007. 80 placental samples from fetuses/neonates with neural tube defects and 50 samples from healthy newborn infants were analyzed for PCBs and PBDEs using electron-capture negative-ionization gas chromatographic mass spectrometry. The median concentrations were 0.89 and 0.54ng/g lipid for the eight PCB congeners and six PBDE congeners detected, respectively. The median concentration of total PCBs was slightly higher in the case samples than in the controls (0.91 vs. 0.89ng/g lipid), but the difference was not significant (P=0.46), as also found for the median concentration of total PBDEs (0.55 vs. 0.54ng/g lipid, P=0.61). For both PCBs and PBDEs, when their placental concentration was above the median of all samples, it was associated with a non-significantly higher or equal risk of neural tube defects. Low levels of PCBs and PBDEs are not likely risk factors for neural tube defects in this population.

Residues and sources recognition of polychlorinated biphenyls in surface sediments of Jiaojiang Estuary, East China Sea

Twenty-three surface sediment samples were collected from Jiaojiang Estuary, East China Sea in order to assess the distribution, possible sources, and potential risk of polychlorinated biphenyls (PCBs) in the environment. Total concentrations of PCBs ranged from 4.93 to 108.79 ng g(-1) dry weight for all sampling stations, with a substantial higher concentration in the inner part of the estuary than the outer part of the estuary. PCB patterns in sediments from sites 1-8 were extremely dominated by tetra-PCBs, which probably due to the discharge of local industrial plants but not the expected input from the nearby e-waste recycling areas. Principal component analysis revealed that the sources of PCBs for sites 9-23 were associated with Aroclor 1248 or Aroclor 1221. However, physical migration and bio-degradation may also play a role on PCB distribution. Hazard assessment of PCBs indicated possible toxic potential, particularly in areas close to point sources.

Environmental contamination of ready meals by polychlorinated biphenyls (PCBs)

The level of polychlorinated biphenyls (PCBs) contamination in ready meals was investigated to determine exposure compared to other foodstuffs. Chilled ready meals from nine categories (ambient, Chinese, Indian, Traditional UK, Italian, American Tex-Mex, Vegetarian and Organic), and three samples within each category were Soxhlet extracted in triplicate with hexane for 24 h, followed by a clean-up on deactivated silica gel. The cleaned extracts were concentrated to 1 ml under N(2) gas and analyzed on gas chromatography mass spectrometry (GC-MS) for 7 target PCBs (congeners 28, 52, 101, 118, 153, 138, and 180). Individual congener concentrations ranged from non-detectable to 0.40 ng g(-1) (wet weight). The cumulative concentration of all congeners (ΣPCBs) ranged between 0.20 and 1.00 ng g(-1) (wet weight). These values translate into exposure levels of less than 1 μg kg(-1)day(-1) for reference men and women of 70 and 57 kg, respectively. This preliminary study demonstrates that ready meals, like many other foods, are contaminated by PCBs and may represent an important route of human exposure given contemporary changes in consumer food choice. Even though low levels of contamination were observed, long-term exposure for population groups consuming a high volume of ready meals may have cause for concern regarding chronic health risks.

Are reductions in industrial organic contaminants emissions in rich countries achieved partly by export of toxic wastes?

Recent studies show that PCB (polychlorinated biphenyl) air concentrations remain surprisingly high in parts of Africa and Asia. These are regions where PCBs were never extensively used, but which are implicated as recipients of obsolete products and wastes containing PCBs and other industrial organic contaminants, such as halogenated flame retardants (HFRs). We hypothesize that there may be different trends in emissions across the globe, whereby emissions of some industrial organic contaminants may be decreasing faster in former use regions (due to emission reductions combined with uncontrolled export), at the expense of regions receiving these substances as obsolete products and wastes. We conclude that the potential for detrimental effects on the environment and human health due to long-range transport by air, water, or wastes should be of equal concern when managing and regulating industrial organic contaminants. This calls for a better integration of life-cycle approaches in the management and regulation of industrial organic contaminants in order to protect environmental and human health on a global scale. Yet, little remains known about the amounts of industrial organic contaminants exported outside former use regions as different types of wastes because of the often illicit nature of these operations.

Current needs and future directions of occupational safety and heath in a globalized world

This summary provides a synopsis of talks included in a symposium entitled "Current Needs and Future Directions of Occupational Safety and Heath in a Globalized World". The purpose of the symposium was to (1) highlight national and international agencies with occupational health related activities; (2) address electronic (e-)waste issues in developing countries where exposures are secondary to the handling and scavenging of scrap; and (3) discuss the effects of hazardous materials, such as polycyclic aromatic hydrocarbon (PAH) and tobacco smoke on child intelligence quotient (IQ) in developing countries.

Levels of PCDD/Fs and DL-PCBs in selected foods and estimated dietary intake for the local residents of Luqiao and Yuhang in Zhejiang, China

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) were measured by high resolution gas chromatograph/high resolution mass spectrometer (HRGC/HRMS) in six food groups from Luqiao (LQ) where the e-waste has been recycled and from Yuhang (YH) where the agriculture dominates in Zhejiang Province in China. The total WHO-TEQ values of PCDD/Fs and DL-PCBs in selected foods from LQ were significantly much higher than those from YH. The highest level of the total WHO-TEQ was in crucian carp (10.87 pg g(-1) w.w.) followed by duck (3.77 pg g(-1) w.w.), hen eggs (2.80 pg g(-1) w.w.), chicken (2.43 pg g(-1) w.w.), rice (0.08 pg g(-1) w.w.) and vegetables (0.022 pg g(-1) w.w.) in LQ. By contrast, the highest levels were measured in duck (0.74 pg g(-1) w.w.) followed by hen eggs (0.69 pg g(-1) w.w.), crucian carp (0.55 pg g(-1) w.w.), chicken (0.44 pg g(-1) w.w.), vegetables (0.002 pg g(-1) w.w.) and rice (0.0002 pg g(-1) w.w.) in YH, respectively. The monthly intake of PCDD/Fs and DL-PCBs for the local residents was 401.75 pg WHO-TEQ g(-1) w.w. in LQ, which is above the provisional tolerable monthly intake (PTMI) set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). We determined a monthly intake of 37.13 pg WHO-TEQ g(-1)w.w. in YH, which is below the PTMI. Crucian carp was the predominant contributor to the estimated monthly intake (EMI), accounting for 67.74% and 36.51% in LQ and YH, respectively. High levels of PCDD/Fs and DL-PCBs in selected foods indicate severe contamination of these pollutants in the e-waste recycling site.

Daily intake and human risk assessment of organochlorine pesticides (OCPs) based on Cambodian market basket data

To assess organochlorine pesticide (OCP) contaminations and its possible adverse health impacts, different food samples were collected from three areas of Cambodia, one of the poorest countries in the world. The ∑OCP concentrations in Kampong Cham, Kratie and Kandal provinces ranged from 1.28 to 188 (median 3.11), 1.06 to 25.1 (5.59) and 2.20 to 103 (20.6) ng g(-1), respectively. The dichlorodiphenyltrichloroethanes (DDTs) were the predominant OCPs and accounted for 62.2% (median) among all foodstuffs. Congener profile analyses suggested that there were new input sources of DDTs and hexachlorocyclohexanes (HCHs) in Cambodia, particularly in Kandal province. The estimated daily intake of OCPs (330 ng kg(-1)day(-1)) for residents in Kandal province ranked No. 1 among the 13 compared countries or regions. On the basis of 95th percentile concentrations, the carcinogenic hazard ratios (HRs) of most investigated individual OCPs in vegetable and fish in Cambodia exceeding unity. Particularly for α-HCH in vegetable, the 95th HR was as high as 186. The data revealed that there is a great cancer risk for the local residents with life time consumption of OCP contaminated vegetable and fish. To our knowledge, this the first study to evaluate the daily intakes of OCPs in Cambodia.

Exposure to PCBs, through inhalation, dermal contact and dust ingestion at Taizhou, China--a major site for recycling transformers

Air samples containing gaseous and particulate phases were collected from e-waste workplaces and residential areas of an intensive e-waste recycling area and compared with a reference site. The highest total concentration of PCBs was detected at transformer recycling workshops (17.6 ng m(-3)), followed by the residential area (3.37 ng m(-3)) at Taizhou, and the lowest was obtained at the residential area of the reference site, Lin'an (0.46 ng m(-3)). The same trend was also observed with regards to PCB levels in dust samples. The highest average PCBs level of 2824 ng g(-1) (dry wt) was found in the transformer recycling workshops, and was significantly higher than that of residential areas of Taizhou (572 ng g(-1) dry wt) and Lin'an (42.4 ng g(-1) dry wt). WHO-PCB-TEQ level in the workshops of Taizhou was 2216 pg TEQ(1998)g(-1) dry wt or 2159 pg TEQ(2005)g(-1) dry wt, due to the high abundance of PCB 126 (21.5 ng g(-1) dry wt), which contributed 97% or 99% of WHO-PCB-TEQs. The estimated intake of PCBs via dust ingestion and dermal absorption by transformer recycling workers were 77.5×10(-5) and 36.0×10(-5) pg WHO-PCB-TEQ(1998)kg(-1)d(-1), and 67.3×10(-5) and 31.3×10(-5) pg WHO-PCB-TEQ(2005)kg(-1)d(-1), respectively.