Toxicity Assessment of Municipal Solid Waste Landfill Leachate Collected in Different Seasons from Okhala Landfill Site of Delhi

Recent studies of leachate induced toxicity have mainly focused on crude leachates collected once from the landfill site, while little attention has been paid to the changes in toxicity resulting from the varying leachate concentration with respect to seasonal variation. The present study deals with the toxicological effects of municipal landfill leachate on Vicia faba. Leachate samples were collected in different seasons (summer, monsoon and winter) and toxicity study was performed via various parameters like germination inhibition, growth, chlorophyll content, lipid peroxidation and activities of antioxidant enzymes. The results show that landfill leachate of all three seasons promoted the growth and chlorophyll content at lower doses for short exposure time but at the higher doses there was inhibition of growth as well as reduction in the chlorophyll content. There was a dose dependent elevation in the malondialdehyde (MDA) level and inhibited antioxidant enzyme activities. The physiological responses varied as a function of leachate concentration which was further dependent on the season of leachate collection. Therefore, this study suggests that the leachate collected in all the three seasons is toxic and may pose a health effect to the general public directly or indirectly. It also suggests that the most important aspect for the treatment of landfill leachate is controlling its concentration which varies with respect to the seasons of leachate collection.