Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/7/2011
Publication Date: 11/15/2011
Citation: Lozano, N., Rice, C., Torrents, A., Ramirez, M. 2011. Fate of triclosan and methyltriclosan in soil from biosolids application [abstract]. Society of Toxicology and Chemistry, 32:70. Interpretive Summary:
Technical Abstract: Biosolids contain synthetic chemicals that have the potential to alter soil microbial communities and disrupt endocrine functions if they move offsite. In this study, the persistence of triclosan (TCS), an antibacterial compound normally found in biosolids and in soils after biosolids applications was evaluated. The fate of its biodegradation product, Methyltriclosan (MeTCS), was also examined. TCS and MeTCS concentrations were analyzed in biosolids samples collected every two months from a large waste water treatment plant (WWTP) over 4 years. An experimental agricultural plot was treated with a single biosolid application from this plant (average TCS and MeTCS concentrations of 15.6 ± 0.6 and 0.12 ± 0.01 µg g-1 dry wt.) and surface soil samples were collected several times afterward, over a three year period. In the experimental plot, for the first 8 months, concentration of TCS in the soil gradually increased with maximum levels of 63.7 ± 14.1 ng g-1 dry wt., far below the predicted maximum concentration of 307.5 ng g-1 dry wt. After one year, TCS disappearance corresponded with MeTCS appearance, suggesting in-situ biodegradation. The results suggest that soil incorporation and degradation processes are taking place simultaneously and thus soil concentrations are always far below the predicted maximum concentration. In this study, TCS background levels are achieved within two years. TCS half-life was determined as 104 d and MeTCS half life was estimated to be more than 4 times this value.