Biological Degradation of Common Pharmaceuticals and Personal Care Products in Soils with High Water Content

Biological degradation rates of six pharmaceuticals and personal care products were examined in soil from a land application site and in adjacent soil with no prior history of effluent exposure. Microbial degradation rates were compared over 2 weeks under standing water or saturated conditions and draining conditions after having been saturated for 3 days. Biological degradation of 17 beta-estradiol exhibited rapid rates of biological degradation under both saturated and draining conditions. Half-lives for 17 beta-estradiol ranged from 1.5 to 4 days; 66-97% was lost from the soils. Estriol showed a pattern of biological degradation in both saturated and draining conditions though the half-lives were longer (8.7-25.9 days) than those observed for 17 beta-estradiol. Twenty-eight percent to 73% of estriol was lost over the 14 days treatment period. Estrone and 17 alpha-ethinylestradiol exhibited slower rates of biological transformation under saturated and draining conditions. Half-lives for estrone ranged between 27.5 and 56.8 days with loss of at most 21%. 17 alpha-ethinylestradiol exhibited half-lives of 22.6-207 days. Half-life data for ibuprofen ranged from 30.4 to 1,706.4 days in this experiment. Losses of up to 17% were observed in draining soils. Triclosan loss was at most 10%, and half-lives were 70.9-398.8 days. In all cases, soils that were draining from saturated conditions exhibited faster degradation rates than soils that remained saturated. Prior exposure of the soil to effluent did not always result in higher biological degradation rates.