Unmasking the spread, carcinogenic-non carcinogenic risk characterization, and source fingerprinting of organochlorine pesticides (OCPs) in soil and vegetables of Gaya, Bihar, India

The use of organochlorine pesticides (OCPs) in specific regions is still prevalent. Moreover, the impact of past utilization can be observed in the present environmental matrices. The present study monitored the extent of contamination of OCPs in the soil and vegetable samples of Gaya, Bihar, India. For this, 63 soil and vegetable samples were collected from the vegetable cultivated area of Gaya. The collected samples were extracted using a Soxhlet extraction unit and OCPs were analysed with a gas chromatography-mass spectrometry detector. The concentration data generated from the analysis were interpreted using statistical tools and software. Mean concentration (μg/g) of Σ₁₉OCPs in soil from residential, agricultural, commercial, and polyhouse sites were 0.69, 2.21, 0.17, and 0.72, respectively. Similarly, in vegetable samples, mean concentration (μg/g) of Σ₁₉OCPs were 0.91, 0.96, 1.00, and 0.67, respectively. Among the monitored vegetable types, the concentration of OCPs increased in the order: pods > tubers > leaves > fruits > roots > stem. The bioconcentration factor of 19 OCPs showed that 61.90% of vegetable samples were hyperaccumulators. The results of molecular diagnostic ratio and positive matrix factorization reported the recent inputs of heptachlor, aldrin, endrin and methoxychlor; the past application of dichlorodimethyltrichloroethane (DDT), endosulfan, and chlordane; and the degradation of DDT to its metabolites and aldrin to dieldrin, which make up an overall source profile of OCPs in study area. The study found that incremental lifetime cancer risks and hazard quotients ranged from 6.98 × 10^-8 to 1.31 × 10^-5 and 4.25 × 10^-2 to 4.63 × 10^-1, respectively in vegetable samples which indicate low to high ILCR and low non-carcinogenic risk to populations exposed to OCPs. The study indicates the long lasting impact of past pesticide use by studying the contamination in soil and vegetables, and raises serious concerns about food safety. The contamination poses direct health risk to consumers related to potential carcinogenic and endocrine disrupting effects. Thus monitoring on the ground level could be a force to modify region specific policies, health, and remediation measures related to exposure to OCPs.