LAUSR

This preliminary investigationhighlights the occurrence of organochlorine pesticides (OCPs) in the indoor environment of a megacity, Lahore, Pakistan using the dust ensnared by air-conditioner filters. The Σ16 OCPs concentration ranged from 7.53-1272.87 ng/g with the highest percent contribution by ΣDDT (dichlorodiphenyltrichloroethane; 87.21 %) and aldrin(6.58 %).The spatial variation of OCPs profile revealed relatively higher concentration from homes near to agricultural and abandoned DDT manufacturing sites.Calculated isomer ratiosrevealed historic sources of hexachlorocyclohexanes (HCHs) and the fresh input of technical DDT and chlordane by the dwellers. The air conditioner dust was helpful to better understand the health risk in the indoor environment. So fara high lifetime cancer risk (10-3 )was predicted for toddlersviaaccidental ingestion, inhalation and dermal exposure. Similarly, thenon-carcinogenic risk-based hazard quotient was found to be high for toddlers (6.94) and within the permissible limit (< 1) for adults.