Risk Assessment of Human Exposure to Polychlorinated Biphenyls via Indoor and Outdoor Dust

The polychlorinated biphenyls (PCBs) in indoor and outdoor dust around the traffic road in Hunan Province were sampled and detected. The ∑PCBs in indoor dust ranged from 156-507ng/g, with a median of 362ng/g, and the ∑PCBs in outdoor dust ranged from 106-955ng/g, with a median of 406ng/g. Similar pattern of PCBs was observed in indoor and outdoor dust, which was dominated by Penta-PCBs and Hexa-PCBs. Risk assessment showed that cancer risk of human exposure to PCBs via dust varied from 1.28-2.97×10-7, with a median of 2.31×10-7, when the high slope factor was employed, and the risk ranged from 6.38×10-8-1.49×10-7, with a median of 1.16×10-7，when the central slope factor was employed. All of the risk values were below the acceptable risk level (1×10-6), which may indicate the relative safety of the present environment.