Organochlorine pesticide contamination of soils and dust from an urban environment in the Niger Delta of Nigeria.

The concentrations, sources, and risk of twenty organochlorine pesticides (OCPs) in soils and dusts from a typical urban setting in the Niger Delta of Nigeria were examined. The Σ20 OCP concentrations (ng g-1) varied from 4.49 to 150 with an average value of 32.6 for soil, 4.67 to 21.5 with an average of 11.7 for indoor dust, and 1.6 to 96.7 with an average value of 23.5 for outdoor dust. The Σ20 OCP concentrations in these media were in the order: soil > outdoor dust > indoor dust, which was in contrast with the order of the detection frequency, i.e., indoor dust (95 to 100 %) > soil (60 to 90 %) > outdoor dust (30 to 80 %). The concentrations of the different OCP classes in these media followed the order: aldrin + dieldrin + endrin and its isomers (Drins) > chlordanes > dichlorodiphenyltrichloroethane (DDTs) > hexachlorocyclohexane (HCHs) > endosulfans for outdoor dust and soil, while that of the indoor dust followed the order: Drins > chlordanes > endosulfans > DDTs > HCHs. The cancer risk values for human exposure to OCPs in these sites exceeded 10-6 which indicates possible carcinogenic risks. The sources of OCPs in these media reflected both past use and recent inputs.

Safety evaluation of organochlorine pesticides and polybrominated diphenyl ethers in imported canned fish in Nigeria.

Organochlorine pesticide (OCP) and polybrominated diphenyl ether (PBDE) concentrations were measured in thirty popular brands of imported canned fish (mackerel, sardines, and tuna) in Nigeria to ascertain potential threats to humans arising from their consumption. The Σ20 OCP concentrations in mackerel ranged from 0.47 to 7.36 ng g-1, while those of tuna and sardines varied from 1.06 to 2.19 and 0.11 to 12.7 ng g-1, respectively. The Σ39 PBDE concentrations in mackerel varied from 0.06 to 4.21 ng g-1, while those of tuna and sardines ranged from 0.19 to 3.18 and 0.04 to 8.26 ng g-1, respectively. The estimated daily intake (EDI) of OCPs and PBDEs from ingestion of the canned fish by adults and children were in the magnitude of 0.03 to 17.6 ng kg-1 bw day-1 and 9.9 × 10-3 to 11.5 ng kg-1 bw day-1 respectively. The hazard index (HI) and total cancer risk (TCR) values for OCPs and PBDEs from ingestion of the canned fish were less than 1 and 10-6, respectively. The dietary intakes of OCPs and PBDEs from these brands of canned fish by adults and children result in no adverse non-cancer and cancer risks.