Janet Kit Yan Chan

Environmental impact and human exposure to PCBs in Guiyu, an electronic waste recycling site in China

PCB levels in fish (collected from local rivers), atmosphere and human milk samples have been studied to determine the exposure levels of PCBs for local residents and e-waste workers in Guiyu, a major electronic waste scrapping center in China. The source appointment and correlation analyses showed that homologue composition of PCBs in 7 species of fish were consistent and similar to commercial PCBs Aroclor 1248. PCB levels in air surrounding the open burning site were significantly higher than those in residential area. Inhalation exposure contributed 27% and 93% to the total body loadings (the sum of dietary and inhalation exposure) of the local residents, and e-waste workers engaged in open burning respectively. Total PCB concentrations in human milk ranged from N.D. to 57.6 ng/g lipid, with an average of 9.50 ng/g lipid. The present results indicated that commercial PCBs derived from e-waste recycling are major sources of PCBs accumulating in different environmental media, leading to the accumulation of high chlorinated biphenyls in human beings.

Body burdens of polybrominated diphenyl ethers in childbearing-aged women at an intensive electronic-waste recycling site in China

Background, aim and scopeThis study is the first to investigate PBDE body burden with regard to the concurrent analyses of multiple human matrices, namely milk, placenta, and hair, collected from a group of childbearing-aged women at an electronic waste (e-waste) recycling site to determine the partitioning of PBDEs in these different human matrices and the possible health risks imposed to infants at the e-waste recycling site.Methods and methodsFive sets of milk, placenta, and hair samples were collected from an e-waste site (Taizhou, Zhejiang Province) and a reference site (Lin’an city, Zhejiang Province; 245xa0km away from Taizhou) in China. The concentrations of total PBDEs in different human tissues were analyzed according to US EPA standard methods.ResultsPBDE body burdens of women from the e-waste site (milk 117u2009±u2009191, 8.89–457xa0ng/g fat, placenta 19.5u2009±u200929.9, 1.28–72.1xa0ng/g fat, hair 110u2009±u2009210, 8.47–486xa0ng/g dry wt.) showed significantly higher levels than those from the reference site (milk 2.06u2009±u20090.94, 1.0–3.56xa0ng/g fat, placenta 1.02u2009±u20090.36, 0.59–1.42xa0ng/g fat, hair 3.57u2009±u20092.03, 1.56–5.61xa0ng/g dry wt.) and were higher than those reported in other studies, due to e-waste recycling operations, especially open burning. On a dry-weight basis, the following trend was found for PBDE among the samples from Taizhou: hair≫milk>placenta. Among the donors, the body burden of an e-waste worker ranked second. Higher brominated BDEs (hepta-BDEs) contributed a significantly greater proportion to total PBDEs in hair of the Taizhou women (20%) than that in milk (2.9%) and in placenta (2.6%). The estimated intake of PBDEs of 6-month-old breastfed infants living at the e-waste site was 572u2009±u2009839xa0ng/kg body wt/day, which was 57 times higher than that of infants from the reference site (10.1u2009±u20094.60xa0ng/kg body wt/day). Moreover, the maximum calculated value (2,240xa0ng/kg body wt/day) exceeded the chronic oral reference dose for penta-BDE (2,000xa0ng/kg/day) of US EPA.DiscussionBDE-47 was the dominant congener accounting for 20–30% in all the individual samples, while higher-brominated congeners, for example, BDE-183 and BDE-190, contributed between 2% and 20%. The presence of hepta-BDE congeners (BDE-181, BDE-190) in hair of the women in Taizhou suggest that thermal degradation of Deca-BDE from the open burning of e-waste may have been their source because these congeners are not found in either Penta-BDE or Octa-BDE technical products. Of the three types of samples analyzed, it was also suspected that hair may be more favorable to higher-brominated compounds which might explain why the hair samples contained the highest total PBDE concentrations and the highest proportion of higher-brominated BDEs (hepta-BDEs).ConclusionThis study provides evidence that primitive e-waste recycling in China leads to high PBDE body burdens in local residents and can potentially threaten the health of infants.Recommendations and perspectivesControl measures should be imposed to minimize the level of pollutants resulting from e-waste processing operations to the environment and to humans. In-depth investigations on epidemiological studies of health impacts caused by e-waste recycling operations should be conducted. It is recommended that further measurements of PBDE levels in local food (e.g., fish, shellfish, dairy products, meat, fruits, and vegetables), dust, air, water, and human specimens be collected from a larger sample size at the e-waste processing site for the determination of human exposure pathways to PBDEs.

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.

Bioaccessibility of polychlorinated biphenyls in different foods using an in vitro digestion method

Bioaccessibility of organic pollutants in food is important for exposure estimation and risk assessment. An in vitro enzyme digestion experiment was carried out to analyze the bioaccessibility of PCBs in different foods including freshwater fish (bighead carp and oriental weather fish) and vegetables (spinach and cabbage). The results indicated that the bioaccessibility of PCBs in freshwater fish (3%) was much lower than that in leafy vegetables (25%). Based on field survey, the daily exposure TEQ value from these two types of food was 17.9 pg/kg bw/day. However, when bioaccessibility was taken into consideration, the value decreased to 0.61 pg/kg bw/day. Therefore, the forms of PCBs existing in food strongly influenced the bioavailability for humans, which may have important implications on dietary exposure. To our knowledge, this is the first paper to illustrate the bioaccessibility of PCBs in different foods using an in vitro digestion method.

Dietary intake of PBDEs of residents at two major electronic waste recycling sites in China

The dietary intake of polybrominated diphenyl ether (PBDE) of local residents from 2 major electronic waste (e-waste) processing sites (Guiyu, Guangdong Province and Taizhou, Zhejiang Province) in China was investigated. Seventy-four food items were collected from these sites, divided into 9 food groups (freshwater fish, marine fish, shellfish, pork, poultry, chicken offal, egg, vegetables and cereals), and examined for residual PBDE concentrations. Out of all food items examined, the freshwater bighead carp (Aristichthys nobilis) contained extremely high (11,400±254 ng/g wet wt.) concentrations of PBDE, the highest concentrations amongst published data concerning PBDE detected in freshwater fish. Food consumption data obtained through semi-quantitative food intake questionnaires showed that Guiyu residents had a PBDE dietary intake of 931±772 ng/kg bw/day, of which BDE-47 (584 ng/kg bw/day) exceeded the US EPAs reference dose (100 ng/kg/day). Taizhou (44.7±26.3 ng/kg bw/day) and Linan (1.94±0.86 ng/kg bw/day) residents exhibited lower readings. The main dietary source of PBDEs in Guiyu and Taizhou residents was seafood (88-98%) and pork (41%) in Linan. The present results indicated that health risks arising from PBDE dietary exposure are of significance in terms of public health and food safety to local residents of e-waste processing sites.

DDTs in mothers' milk, placenta and hair, and health risk assessment for infants at two coastal and inland cities in China

This study is a one of the very few investigating the dichloro-diphenyl-trichloroethanes (DDTs) (summation of o,p-DDE, p,p-DDE, o,p-DDD, p,p-DDD, o,p-DDT, and p,p-DDT) in multiple human matrices in mothers milk, placenta and hair collected from residents from two coastal cities: Guiyu (GY) and Taizhou (TZ) and one inland city: Linan (LA). TZ (milk: 360±319ng/g lipid wt.) showed significantly higher concentrations of DDTs than those from LA (milk: 190±131ng/g lipid wt.), whereas, concentrations of DDTs in GY (milk: 305±109ng/g lipid wt.) were in between TZ and LA. In addition, levels of DDTs in the human tissues from TZ (placenta: 122±109ng/g lipid wt.; hair: 79.9±215ng/g dry wt.) were significantly higher than those from Linan (placenta: 49.2±30.2ng/g lipid wt.; hair: 10.8±7.09ng/g dry wt.). The above concentrations of DDTs in milk exceeded the Codex Maximum Residue Limits/Extraneous Maximum Residue Limits for milk (20ng/g lipid wt. whole milk), indicating that the human milk samples were grossly polluted. The present study revealed that human specimens collected from the coastal city (TZ) were more contaminated with inland one (LA), based on the levels of DDTs contained in samples which may be due to the higher dietary exposure to DDTs via consumption of contaminated seafood. The estimated daily intakes of DDTs by GY, TZ and LA infants were 1.69±1.86, 1.48±0.79, and 0.95±0.73μg/kg body wt./day, respectively which did not exceed 10μg/kg body wt./day, the provisional tolerable daily intake proposed by the Food and Agriculture Organization/World Health Organization.

Dietary exposure to DDTs in two coastal cities and an inland city in China.

Dietary intakes of dichloro-diphenyl-trichloroethanes (DDTs) of residents from two coastal cities: Guiyu (GY) and Taizhou (TZ) and one inland city: Linan (HZ) were investigated by collecting 73 food items (divided into 9 food groups). The oriental weatherfish and white crab (both from TZ) contained higher DDTs (112±1.81 and 70.1±1.81 ng/g wet wt, respectively) than the maximum admissible concentration (50 ng/g wet wt) set by the European Union for human consumption. Furthermore, 40% of TZ seafood, 56% of GY and 30% of HZ freshwater fish exceeded the guideline for subsistence fish eaters for DDTs (14.4 ng/g wet wt) defined by the United States Environmental Protection Agency (US EPA). The estimated daily intakes of DDTs for TZ (52.1 ng/kg bw/day) and GZ (31.5 ng/kg bw/day) were significantly higher than for HZ (13.0 ng/g wet wt, p<0.05), these values were below the US EPA oral reference dose (500 ng/kg bw/day) and the Food and Agriculture Organization of the United Nations and the World Health Organization provisional tolerable daily intake (10,000 ng/kg bw/day).

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 70xa0pg 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 363xa0ng/g lipid, 224xa0ng/g lipid, and 386xa0ng/g dry wt. Respectively, three times higher than those samples collected from the reference site (Linan). 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 (12.9xa0pg WHO-PCB-TEQ/kg bw/day) and infants (438xa0pg 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 (1-4xa0pg 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.

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 EUs 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 EUs 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.