Atrazine and bifenthrin persistence study was carried out in three sludge amended soil under laboratory condition. Atrazine persisted shorter in sludge amended soil sludge-3 (half-life 23.4 days) followed by sludge-2 (half-life 30.1 days) and sludge-1 (half-life 37.1 days) than unamended control (half-life 150.5 days). Bifenthrin followed the similar pattern with sludge-3 (half-life 43.1 days) which increased to 50.3, 60.2 and 75.2 days, respectively in sludge-2, sludge-1 and unamended control representing an immense influence of sludges on degradation. Duncan's Multiple Range Test revealed that carbon mineralization process was significantly influenced by all the sludges (p < 0.0001). Sludge-3 indicated highest Cmin (initial 118.16 to final 133.64 mg CO2-C/kg) in bifenthrin and 129.91 mg CO2-C/kg in atrazine. The relatively high Cmin rate in sludge amended soil than unamended control suggested a lower persistency of both the pesticides and thus decreasing its potential ecological risk. Sludge-3 sludge amended soil increased the dehydrogenase enzyme activity as compared to sludge-1 and sludge-2 sludge in atrazine.
Keywords: Atrazine; Bifenthrin; Carbon mineralization; Degradation; Dehydrogenase; Sludge.