| Short-chain chlorinated paraffins(SCCPs,C10-13)was listed as one of new Persistent Organic Pollutants(POP)in 2017,have larger quantities in the environment and adverse effects on ecological environment and human health,therefore,have received extensive attention.China is the largest chlorinated paraffin(CP)producer and consumer worldwide.Given that CP production is a major source of SCCP pollution,the effects of CP production on the environment inside and outside of CP production plants are worth revealing.The concentrations and specific congener patterns of SCCPs in various environmental matrices,such as air,soil,dust,sediment and water,inside and outside of a chosen CP production plant surrounded by farmlands and villages were analyzed to explore SCCP pollution and transportation behaviors.Inside the CP production plant,SCCP concentrations in air,dust and soil samples were 129.4-1441.8 ng/m3,439.5-16,687.6 μg/g and 27,508.4-554,160.8 ng/g,respectively.The highest SCCP concentration was expectedly found in the production hall.The extremely high SCCP concentrations in soil environment indicated the large potential for CP leakage,possibly resulting from the improper disposal of scrapped production equipment and the accidental leakage of CP products during internal transport.In the farmlands and villages surrounding the plant,SCCP concentrations in air(88.8-332.8 ng/m3)and soil(102.2-440.6 ng/g)samples were dramatically in decline,but still non-neglectable.Through the atmospheric transport,SCCPs released from CP production were transported to outside air and soil environment.In the Xiaoqing River,SCCP concentrations in sediment and water samples were 291.4-2274.9 ng/g and 519.0-6134.9 ng/L,repectively.The treated sewage was the significant source of SCCPs in the river.Average congener abundance profiles among all samples illustrated that lighter groups(C10-11 and Cl5-6)preferred to exist in atmospheric and aquatic environments and undergo long-range transport,whereas heavier groups(C12-13 and Cl7-10)tended toward deposition.Obviously,CP production released considerable amounts of SCCPs,which polluted the in-plant and out-plant environment,which indicate the significance of pollution control during the CP production stage.In the SCCP highly contaminated area,like the CP production plant,human was potentially exposed to SCCPs via non-dietary intake.Thus,SCCP exposure and health risks for employees and local residents in the investigated area should be analyzed and assessed through a combination of obtained data and appropriate models.Ingestion and dermal absorption of indoor dusts was the dominant pathway for the occupational SCCP exposure of employees;while the major exposure pathways for adults and children outside the plant were air inhalation.The daily occupational SCCP exposure of employees in the production hall(21.81 μg/day-kg)exceeded the tolerable daily intake(TDI)given by Canadian Environmental Protection Act,suggesting that production employees were confronted with high health risk from SCCP exposure.This is mainly due to the continued heavy SCCP pollution of dusts in the production hall.Therefore,appropriate physical protection for employees,like anti-dust masks,needs to be applied to avoid the ingestion and skin contact of highly-contaminated dusts.Daily SCCP exposure of employees in office areas(0.57μg/day-kg)and residents near the CP plant(1.22-25.5×10-2 μg/day-kg)were significantly lower,representing low health risk.However,SCCP exposure of office employees and children in this study were higher than those of people in low industrial areas and developed countries.Considering that restriction of SCCP production and usage in China has not been established,the health risk induced by accumulative exposure of residents,especially children,to SCCPs will remain a concern. |
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