Risk assessment of bioaccessible organochlorine pesticides exposure via indoor and outdoor dust

•Different cytotoxic effects on human cell lines were estimated for different dusts.•Higher accumulation for OCPs was found in <63 μm fraction.•Dust was a major route to total OCP exposure for children while low for adults.•The cancer risk of OCPs exposure for 42% of residences was of concern (10−5).•Exposure risks of OCPs via dust ingestion corrected by bioaccessibility were low.

Dust, enriched by dichlorodiphenyltrichloroethanes (DDTs), was defined as a new route of organochlorine pesticides (OCPs) exposure, especially for children. Chemical analyses showed the medians of ∑OCPs were 171 (outdoor) and 520 (indoor) μg kg−1 in Guangzhou (GZ) while 130 (outdoor) and 115 (indoor) μg kg−1 in Hong Kong (HK). Significantly higher accumulative effect of OCPs occurred in the size fractions of <63 and 63-100 μm than 100-280 and 280-2000 μm, therefore 0-100 μm dust particles were used for risk evaluation. Different cytotoxic effects on human hepatocellular live carcinoma cell (HepG2) and human skin keratinocyte cell line (KERTr) were found for extracts of indoor dust and outdoor dust from different functional areas. For total exposure (dust and food), OCPs intake via dust was low for adults (accounting for 0.16-3.78% of total exposure), while for children it was high (8.16-24.4% of total exposure). Non-carcinogenic OCPs exposure via dust was safe for adults; however DDT and Dieldrin exposure for children was higher than Reference Dose (RfD). The cancer risk related to indoor dust exposure for GZ and HK was moderate, below 10−4, while 42% of residences in GZ should be of concern (10−5). However, when bioaccessible OCPs used, daily intake and health risk were found to be greatly lower than the estimates without considering bioaccessibility.