Organic pollutants in indoor dust from Ecuadorian Amazonia areas affected by oil extractivism

Abstract

Fifty-five household dust samples collected within six settlements surrounding oil production complexes along the Ecuadorian Amazonia were analysed to evaluate the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs), phthalates, alkylphenols (APs), bisphenol A (BPA), nicotine, organophosphorus flame retardants (OPFRs), polychlorinated biphenyls (PCBs), legacy organochlorine pesticides (OCs) and organophosphorus pesticides. Studied areas are mainly affected by gas flares emissions and oil spilling coming from extractivist operations and pesticides used in agriculture. Median ΣPAHs values ranged from 739 to 1182 ng g and up to 52% of the PAH dust concentrations were associated to petrogenic activities from crude oil extraction, according to diagnostic ratios. ΣPAHs and toxic equivalents based on benzo[a]pyrene concentration (ΣTEQ, ng g) suggested similar toxicities among the different areas. Individual lifetime cancer risk (ILCR) was calculated for ingestion and dermal contact exposure routes and a non-acceptable total carcinogenic risk of up to 10 (one case per ten thousand people) was found for newborns from 0 to 3 years-old in Pimampiro area. Plasticisers and OPFRs were present in dust at maximum median concentrations of 332,507 ng g (DEHP), 5,249 ng g (DBP), 1,885 ng g (BPA), 871 ng g (TBOEP) and 122 ng g (TEHP). Some dust samples from Ecuadorian houses had high maximum levels of legacy and modern pesticides such as chlorpyrifos (up to 44,176 ng g), 4,4′-DDT (12,958 ng g), malathion (34,748 ng g) and α+β-endosulfan (10,660 ng g) attributed to inappropriate use and storage of the pesticides. Finally, nicotine was seldom detected (36 ng g). The sources and risks of these compounds are discussed based on the activities carried out in the study areas and attending to an additional non-cancer risk assessment which showed high hazard quotients (HQ) and hazard indexes (HI) for DEHP, DBP, 4,4′-DDT, malathion, chlorpyrifos, naphthalene and benzo[a]pyrene in newborns and children up to 16 years-old.