Influence of organic amendment on fate of acetaminophen and sulfamethoxazole in soil.

Land application of biosolids or compost constitutes an important route of soil contamination by emerging contaminants such as acetaminophen and sulfamethoxazole. Using (14)C labeling, we evaluated the influence of biosolids and compost on individual fate processes of acetaminophen and sulfamethoxazole in soil. The amendment of biosolids or compost consistently inhibited the mineralization of both compounds but simultaneously enhanced the dissipation of their extractable residues or parent form. Immediately after treatment, the majority of (14)C-residue became non-extractable, reaching 80.3-92.3% of the applied amount at the end of 84-d incubation. Addition of biosolids or compost appreciably accelerated the formation of bound residue, likely due to the fact that the organic material provided additional sites for binding interactions or introduced exogenous microorganisms facilitating chemical transformations. This effect of biosolids or compost should be considered in risk assessment of these and other emerging contaminants.