Health Risk Assessment Of Polychlorinated Biphenyls Exposure In A Typical Village Engaged In Solid Waste Recycling

As the synthetic chlorinated persistent organic pollutants (POPs) in the environment, Polychlorinated Biphenyls (PCBs) have carcinogenicity, neurotoxicity and endocrine disrupting effects on human bodies. Taizhou is the most typical disassembly of solid waste in China, and its primitive methods used for e-waste recycling have caused severe environmental pollution, which have threatened agricultural products safety and human health. In the present study, we conducted a dietary investigation for residents and a comprehensive survey on local soil, groundwater, air and foodstuffs in order to carry out health risk assessment on local residents in the study area and screen out the main PCBs exposure pathways and the maximum contribution of environmental media, thus providing effective suggestions to guide the residents how to reduce PCBs exposure. The main results are presented as follows:(1) The results of dietary investigation for local residents in the study areaFood Frequency Questionnaire method was used in the dietary investigation for local residents. The results showed that vegetables, cereals and fruit were the main source of their dietary intake. While animal derived food contributed much smaller portion, which was lower than the average consumption of ordinary rural residents in Zhejiang Province. This may be related to the strengthening of awareness to environmental pollution.(2)Levels of PCBs in various environmental mediaSamples of soil, groundwater, air and agricultural products were collected to investigate the PCBs concentrations in these environmental media. The results showed that PCBs levels in32soil samples were0.03～1.96mg·kg-1, and the levels of PCBs in38% of the soil samples exceeded the PCBs contaminated soil guideline value for0.20mg·kg-1raised by Zhejiang Province in residential and public land. The concentration range of PCBs in7groundwater samples were ND～0.06μg·L-1, and only one sample can be detected the existence of PCBs. Gaseous PCBs levels was27.4～62.4ng·m-3, and the concentration of aerosol PCBs was0.5ng·m-3, both of which were higher than those of home and abroad. A total of60samples of agricultural products were analyzed for PCBs residual levels. The local production of vegetables and poultry can be detected the presence of PCBs, and the concentration range was1.6～83ng·g-1, which could pose a great threat to human health, while PCBs were not detected in13kinds of animal and plant food samples purchased from local markets.(4)Health risk assessment of local residents in the study areaUse the methods of US EPA (1996) to assess health risk of PCBs exposure, while making a corresponding adjustment to the relevant model parameters combined with local actual situation. The non-carcinogenic risk assessment results showed that Hazard Quotients (HQ) was0.43, which was lower than the acceptable risk level (HQ=1). It indicated that the lifetime average daily dose of local residents hasn’t exceeded Reference Dose, and there was certain non-carcinogenic risk in the study area. The level of cancer risk by three exposure pathways was5.79×10-6,which exceeded baseline level of lifetime carcinogenic risk, while the oral ingestion pathway contributed the maximum rate (65.6%). The health risk assessment of PCBs exposure via soil, local poultry and vegetable, groundwater resulted in most of lifetime cancer risk, while PCBs exposure risk through soil was the highest.(5) Suggestions to lower health risk of PCBs exposureIt is suggested that the residents should minimize the consumption of locally produced agricultural production and reduce drinking or using well water in order to effectively lower health risk of PCBs exposure. In addition, it is recommended that relevant departments should mark out heavy, medium, light pollution area based on PCBs pollution status and distribution characteristics to carry out soil bioremediation or risk control measures to ensure health care for local residents.