Spatiotemporal evaluation of hydrochemical facies and pesticide residues in the cardamom plantations of Southern Western Ghats, India

ABSTRACT

In India, Kerala state is considered as the “land of spices” and providing good quality spices to the world especially cardamom, ginger, clove, cinnamon, turmeric, nutmeg, vanilla, tamarind and pepper. To maintain consistency in better crops yield, planters are constantly using pesticides. Most of the time, over-usage causes environmental degradation in terms of water and soil pollution. Highlands of Southern Western Ghats, especially in the Idukki district of Kerala, is famous for cardamom plantations. The widespread use of pesticides in plantations creates irreparable environmental concern due to pesticide residues in water and sediment. Abandoned pesticides are available in the local market with special brand names, and have been regularly used. At the same time organics such as acephate, fenvalerate, methamidophos, atrazine, chlorpyrifos, cypermethrin and ethion with comparable activity have been widely used in the areas of cardamom plantations as pesticides. A systematic field-survey conducted in cardamom plantations during the summer and monsoon seasons in 2020 (before and after the critical COVID-19 pandemic period). The sampling carried out from small streams near the plantations, which finally flows into the Periyar River. The samples collected from each location are carefully preserved and analysed using GC-MS/MS and LC-MS/MS facilities using corresponding pesticide standards. The study identified the presence of acephate and fenvalerate in almost half of the sampling stations, while ethion is absent in all the samples. The rest of the hydrochemical parameters also determined. The potability and irrigational suitability of water-resources evaluated. The study also pointed out that the presence of pesticides is not having much influence on the hydrochemical prospects of water resources. Further studies required to get more information about the status and dynamics of pesticide contamination in other areas of the basin. Such studies are inevitable in mitigating pesticide pollution in a view of sustainable ecosystem management.