FATE OF PESTICIDES IN RIVERBANK FILTRATION : MODEL STUDIES

Abstract

In our study, removal/adsorption of organochlorine pesticide (Endosulfan a, Endosulfan 0) and organophosphorous pesticide (Chlorpyrifos) was determined by using physical model setup (98x65x30cm). Bed material used during the study was procured from local Solani River. For the study, Upper Ganga canal water was used as influent which was prepared by adding targeted pesticides of known concentration (25 p g/L- 2mg/L for chlorpyrifos and 25 pg/L-0.3mg/L for Endosulfans, according to their solubility), model was run continuously in order to. simulate riverbank conditions. Pesticides were quantified using GC-MS after preparation by liquid liquid extraction. It was found that the overall removal efficiency of RBF model for pesticides namely Chlorpyrifos, Endosulfan a and Endosulfan 0 was around 9-29%, 11-24% and 10.2-24% respectively during the study. Moreover, we observed that for less concentration of pesticides in water (around 25p.g/L) lesser removal was achieved (9-11%) while for higher concentration (around 0.3-2mg/L) higher removal of pesticides was achieved (24-29%). Therefore, RBF physical model was found to be more efficient for higher concentration of pesticides and adsorption is the key mechanism responsible for their removal. Keywords: Riverbank Filtration (RBF), GC-MS, Chlorpyrifos, Endosulfan a, Endosulfan 13, Adsorption