Seasonal Variability of Pesticide Residues in Vellode Bird Sanctuary: Implications for Ecosystem Health

This research provides a comprehensive examination of the seasonal fluctuations in pesticide residues within the Vellode Bird Sanctuary, with a particular emphasis on the detection and quantification of organochlorines, organophosphates, synthetic pyrethroids, and herbicides in the sanctuary's aquatic environment. The pesticide analysis was conducted from July 2019 to May 2020. This study period spanned three seasons: monsoon, winter, and summer. Gas Chromatography-Mass Spectrometry (GC-MS) from Perkin Elmer was used to analyze the pesticide residues in lake water. The pesticide analysis showed that aldrin, α-cypermethrin, α-HCH, β-HCH, bifenthrin, butachlor, chlorpyrifos, dimethoate, endosulfan-α, γ-HCH, pendimethalin, phorate, profenophos, p,p'-DDT, and quinalphos were recorded at higher levels during the monsoon season. The values of pesticide residues in the winter and summer seasons were below the level of detectable quantification (less than 0.5 μg/l). The study shows that increased pesticide concentrations during the monsoon are due to runoff from nearby agricultural fields caused by heavy rainfall. In contrast, lower pesticide levels in winter and summer are likely due to reduced pesticide use and rainfall. These findings highlight the significant impact of seasonal variations on pesticide contamination, with greater ecological risks during the monsoon. The sanctuary's aquatic ecosystem is particularly vulnerable during periods of high rainfall, emphasizing the need for targeted conservation and management strategies.