Adsorption and degradation of triclosan and triclocarban in soils and biosolids-amended soils.

Triclosan and triclocarban are antibacterial agents that are widely used in numerous personal care products. Limited information is available on their environmental behavior in soils and soils land applied with wastewaters and biosolids. In this study, laboratory experiments were performed to investigate their adsorption and degradation in soils. Both antibacterial agents adsorbed strongly to the sandy loam and silty clay soils with and without addition of biosolids, with distribution coefficients (K(d)) ranging from 178 to 264 L kg(-1) for triclosan and from 763 to 1187 L kg(-1) for triclocarban. Sorption of triclosan decreased with increase in soil pH from 4 to 8, whereas triclocarban sorption showed no effect within the tested pH range. Competitive sorption was observed when triclosan and triclocarban coexisted, but the cosolute effect was concentration dependent. Biosolids amendment increased the sorption of triclosan and triclocarban, likely due to the addition of soil organic matter, but displayed no significant effect on degradation.