Pollution And Health Risk Assessment Of PCBs In Vegetables In E-waste Recycling Pollution Area And Remediated Area

Polychlorinated biphenyls(PCBs)are one of the typical environmental persistent organic pollutants,which have carcinogenicity,neurotoxicity and endocrine disrupting effects on human bodies.Due to the crudely electronic waste recycling,the environment in Taizhou was seriously polluted by PCBs.It posed a threat to human health by environmental exposure and dietary exposure.The samples of farmland soil,air,irrigation water and vegetables were collected from e-waste recycling pollution area,remediated area and non-dismantling area.The concentration of PCBs was determined and the relationship between PCBs in vegetables and those in environmental media were analyzed.And the local resident dietary exposure to PCBs in the different vegetables were evaluated.Some suggestions were given to guide the residents to avoid the PCBs exposure.The main results are as follows:(1)PCBs levels in agricultural environmental mediaThe average PCBs concentration of farmland soil samples in e-waste recycling pollution area was 210.55 ng/g,and that of remediated area and non-dismantling area were 21.15 ng/g and 14.78 ng/g.The PCB contaminated levels in these area were higher than the domestic and international levels.The main PCB homologs in e-waste recycling pollution area were low chlorinated congeners.While the high chlorinated congeners occupied a large proportion in non-dismantling area.The average concentrations of PCB in air in three area were 103.59 ng/m3,35.40 ng/m3 and 13.69 ng/m3.The tri-chorinated and tetra-chlorinated congener were the largest proportions in the air environment.Lower chlorinated PCBs occurred mainly in the gas phase,while higher chlorinated PCBs were high in particle phase.The average PCBs concentration of irrigation water in e-waste recycling pollution or remediated area was 16.25 ng/g,and that of non-dismantling area was 10.78 ng/g.The hex-chlorinated congener was the largest proportions in the water samples.(2)The characteristics and source of PCBs in vegetablesThe average concentrations in three researching areas were 226.68 ng/g,58.31 ng/g and 35.65 ng/g.The di-chlorinated to tetra-chlorinated congeners occupied largest proportion in the leafy and underground rhizomes vegetables,while the higher chlorinated congeners were increased in legume vegetables.The sources of PCBs in vegetables were analyzed.The PCBs in vegetables were mainly came from farmland soil and the atmosphere.The leafy vegetable was directly affected by the atmosphere,underground rhizome was directly affected by the soil,while the source of PCBs contamination in legume vegetables was unclear.(3)Health risk assessment of local resident about intake of vegetablesThe total cancer risk and hazard quotient of residents via intake PCBs in vegetables in e-waste recycling pollution area were 1.01×1 0-4 and 2.54,both of them were higher than the acceptable risk level.The total cancer risk in remediated area was 3.06×10-5,which was higher than the acceptable level,and the hazard quotient was 0.76.The total cancer risk in non-dismantling area was 6.19×10-6,and the hazard quotient was 0.16.The highest carcinogenic and non-carcinogenic levels appeared in e-waste recycling pollution area,and the carcinogenic risk of PCBs in the remediated area was still high.(4)Suggestions to avoid PCBs exposureIt was suggested that the local government ought to adjust the land planting structure,and stop the cultivation of edible agricultural products,especially the leafy vegetables.The regional-wide control and strict supervision were also recommended.