Organochlorine pesticides in the soils of Cardamom Hill Reserve (CHR), Kerala, India: Geo spatial distribution, ecological and human health risk assessment

The present study assessed the organochlorine pesticides (OCPs) residues in the soils of Cardamom Hill Reserve (CHR), a tropical humid forest landscape of Idukki District of Kerala, India. The concentrations, spatial distribution, health risk for human (both adults and children) due to individual OCPs and ecological risks were estimated. Soil samples were collected randomly from 22 different sampling locations during May 2017 and 2018. The sample preparation was done by QuEChERS method. A total of 17 persistent Organochlorine pesticides (OCPs) were determined by Gas chromatography in split less mode using Electron Capture Detector (ECD). The limit of detection and quantification for OCPs in the soils ranged from 1.57 to 3.74 ng/g and 4.78 to11.33 ng/g respectively. Spatial distributions of OCPs were evaluated using Arc GIS10.5.1 software. The most frequently found OCPs in the soils of the study area were endrin, β-endosulfan, the isomers of HCH, 4, 4′-DDD, dieldrin and endrin aldehyde. The concentration of ∑OCPs were ranged from 6.35 to 118.29 ng/g. Occurrence of pesticides residues in the soils of CHR is due to both ongoing and past usage. Human health risk assessment parameters like Lifetime average daily dose (LADD), incremental lifetime cancer risk (ILCR) and hazard quotient (HQ) for human adults and children due to individual OCPs were also estimated. Estimated LADD were lower than the reference dose and acceptable daily intake. The estimated human health risks were lower than safe limit of non- cancer risk (HQ ≤ 1.0) and low carcinogenic risks (ILCR below 10–6) in these soils. Finding from the present study provided an overview of the current status of OCPs contamination in the soils for the exposed populations are essentially negligible.