Distribution of pesticides in sediments from municipal drains in Delhi, India

Abstract

A study was conducted to assess the levels of organic pollutants i.e. organochlorine pesticides, (OGPs), organophosphate pesticides (OPPs) and herbicides, in sediments from nine major municipal drains in Delhi, India. Sediment samples from Delhi's municipal drains were extracted with acetone/dichloromethane (l:lv/v) and analyzed using GC and HPLC. The average concentration of ΣOCPs, ΣOPPs and Σherbicides was 27.26±9.7 ng g-1 (dry wt.), 80.89±22.4 ng g-1 (dry wt.) and 16.20±4.45 ng g-1(dry wt.), respectively. Among OCPs ΣHCH alone accounts 63% followed by ΣDDT (16%), Xendosulphan (13%) and drins 8%. The ratio of p,p'-DDT/ΣDDT (0.23), p,p'-DDT/p,p'-DDE (0.26) and o,p'-DDT/p,p'-DDT (<0.01) indicates the aged mixture or past usage of DDT and no dicofol type DDT. Among OPPs Chlorpyriphos was the dominant pollutant with 89% of total OPPs. Pendimethalin accounts 77% of total herbicides followed by Butachlor (14%) and Alachlor (9%). The level of herbicides, OCPs and OPPs in this study were compared with Canadian Sediment Quality Guidelines, Interim Sediment Quality Guidelines (ISQG) and Probable Effect Level (PEL) and found much lower than fresh water sediment guideline values. However, it is recommended that regular intensive assessment for persistent organic pollutants and heavy metals to be conducted, due to environmental concerns. © 2011 Asian Network for Scientific Information.