title: Occurrence, profile and spatial distribution of organochlorines pesticides in soil of Nepal: Implication for source apportionment and health risk assessment.
abstract: Nepal is a landlocked country located between world's two most populous countries-India and China where high level of organochlorines pesticides has been reported from multi-environmental matrices. In this study, we investigated the occurrence, distributions and profile of selected OCP chemicals in surface soil samples (N=72) from four major cities of Nepal. Overall, the sum of total OCPs in soil ranged from 20 to 250ng/g with Biratnagar being the most polluted site in Nepal. DDTs and endosulfans were the most abundant OCP chemicals in soil samples. The concentration of DDTs ranged from 8 to 230ng/g, 8-56ng/g, 8-63ng/g, and 8-27ng/g in surface soil, while endosulfans were in the range of 2.9-3.3ng/g, 2.8-8.7ng/g, 2.8-3.4ng/g, 2.8-3.2ng/g in Biratnagar, Kathmandu, Pokhara and Birgunj, respectively. The isomeric ratio of DDT and their metabolites suggested the ongoing usages of technical DDT as well as dicofol in this region. Lower ratio of α/β-endosulfan indicated past application of endosulfans in Nepal. HCHs were less detected OCPs in soil sample accounting only 4-9% of ∑OCPs. The isomeric ratio of α-/γ-HCH indicated that the HCHs may be originated from mixed source of technical HCH as well as lindane use. Scattered plot of TOC and BC showed they were weakly and positively related with concentration of OCPs in soil. Health risk assessment modeling study of OCPs in soil suggested moderate cancer risk with ingestion being the most potential pathway of OCPs exposure.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China. Electronic address: icyadav.bhu@gmail.com.
authors.forename: Ishwar Chandra
authors.initials: IC
authors.lastname: Yadav
authors.affiliation: Centre for Environmental Sciences, Central University of South Bihar, BIT Campus, Patna 800014, Bihar, India.
authors.forename: Ningombam Linthoingambi
authors.initials: NL
authors.lastname: Devi
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China. Electronic address: zhanggan@gig.ac.cn.
authors.forename: Gan
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Padma Kanya Multiple Campus, Tribhuvan University, Bagbazar, Kathmandu, Nepal.
authors.forename: Pawan Raj
authors.initials: PR
authors.lastname: Shakya
mesh_terms: D004784:Environmental Monitoring; D001556:Hexachlorocyclohexane; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D007306:Insecticides / Q000032:analysis*; D009390:Nepal; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D012989:Soil Pollutants; D001556:Hexachlorocyclohexane
keywords: Cancer risk; Isomeric ratio; Lindane; Nepal; Organochlorine