Persistent organic pollutants in residential soils of North India and assessment of human health hazard and risks

Abstract

Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) (dichlorodiphenyltrichloroethane, hexachlorocyclohexane, and their isomers) and dioxin-like polychlorined biphenyls (DL-PCBs) in residential soils from North India have been quantified for the assessment of human health risks. The average concentration based on dry weight basis of ∑PAHs, ∑OCPs, and ∑DL-PCBs were 3600 ± 1600, 8.2 ± 1.6, and 3.6 ± 0.8 μg kg−1, respectively. The observed levels were more or less comparable globally and lower than recommended soil quality guidelines. For risk assessment, lifetime average daily doses (LADD) of ∑PAHs, ∑OCPs, and ∑DL-PCBs for human adults were estimated to be 3.5 × 10−6 mg kg−1 d−1, 9.7 × 10−9 mg kg−1 d−1, and 4.4 × 10−11 mg-TEQ kg−1 d−1, and for children 1.8 × 10−5 mg kg−1 d−1, 5.1 × 10−8 mg kg−1 d−1, and 2.3 × 10−10 mg-TEQ kg−1 d−1. The corresponding incremental lifetime cancer risks for human adults were 3.9 × 10−6, 1.2 × 10−8, 6.7 × 10−6, and for children 2.1 × 10−5, 6.5 × 10−8, 3.5 × 10−5, and lower than the acceptable guideline range of 10−6–10−4 for adults but within that range for children. The non-cancer risks due to OCPs and DL-PCBs were less than 1 (≤1.0). It is concluded that cancer and non-cancer risks for humans through PAHs, PCBs and OCPs in these soils are low.