Retention‐release characteristics of triclocarban and triclosan in biosolids, soils, and biosolids‐amended soils

Abstract

Transport models that incorporate retention/release characteristics of organic compounds in soils and sediments typically assume that organic-carbon normalized partition coefficients (K(OC)) apply to all solid matrices and that the partitioning process is completely reversible. Partition coefficients (K(d)) (from which the K(OC) was calculated), and retention/release characteristics of triclocarban (TCC) and triclosan (TCS) in biosolids, soils, and biosolids-amended soils were determined. Four soils of different physicochemical properties amended with biosolids at 10 g/kg, together with unamended soils, and several biosolids were separately spiked with either [(14)C]TCC or [(14)C]TCS for the various determinations. The hysteresis coefficient values of the two compounds were consistently <1 in all three solid matrices, suggesting strong hysteresis. Multiple desorption steps (24 h each) over several days revealed incomplete desorption of the two compounds from all three solid matrices. The K(d) values determined in biosolids (log K(d) 3.34 +/- 0.13 for TCC and 3.76 +/- 0.39 for TCS) were greater than those determined in soils (log K(d) 1.71 +/- 0.09 for TCC and 2.25 +/- 0.26 for TCS) and biosolids-amended soils (log K(d)1.90 +/- 0.16 for TCC and 2.31 +/- 0.19 for TCS), however, the K(OC) values of all three solid matrices were similar (log K(OC) of 3.82 +/- 0.16 for TCC and 4.26 +/- 0.31 for TCS). Thus, it was concluded that a single or a narrow range of K(OC) values for TCC and TCS may be appropriate to describe retention of the compounds in soils and sediments. However, models that assume complete reversibility of the retention/release processes of the compounds in soils and sediments may not adequately describe the retention/release characteristics of the compounds in soils and sediments, especially when the chemicals are biosolids borne.

Fate of triclosan and triclocarban in soil columns with and without biosolids surface application

“…The result from this study supports a previous finding of limited leaching for TCS and TCC in soil receiving long-term (33-year) biosolids application [13]. The limited leaching of those two compounds is possibly attributable to one or a combination of the following reasons: fast transformation and high partition coefficient (k d ) for soils and biosolids-applied soils [37,38]. The reported k d values by both studies ranged from 177 to 264 L/kg for TCS and from 51 to 1,187 L/kg for TCC for soils with texture varying from fine sand to silty clay soils with and without addition of biosolids.…”

Evaluation of triclosan and triclocarban at river basin scale using monitoring and modeling tools: Implications for controlling of urban domestic sewage discharge

“…The pseudo-partitioning process of TCS and TCC in water and sediment Partitioning of organic compounds between water and sediment phases has been known to be an important process in governing the fate of organic pollutants in aquatic environment (Agyin-Birikorang et al, 2010). The process is usually evaluated by partition coefficient (K d ), which is defined as the ratio of concentrations in sediment to water phase.…”

“…However, the log K OC 0 values were slightly larger than the reported values (4.27 for TCS and 4.70 for TCC), which were obtained by modeling or measuring works USEPA, 2009). Agyin-Birikorang et al (2010) had tested the retention/release characteristics of TCS and TCC in different solids, suggesting that a hysteresis effect occurred during the desorption of the two compounds from solid matrices. This might be the reason behind the calculated higher K OC 0 values in the riverine environments.…”

Effects of multiwalled carbon nanotubes and triclocarban on several eukaryotic cell lines: elucidating cytotoxicity, endocrine disruption, and reactive oxygen species generation

“…Therefore, they are detected often and in rather high concentrations in the environment [53]. TCC is a high-production volume chemical [54] that is widely used as an antimicrobial compound [53,55]. It is able to adsorb on the cell membrane and to destroy its semi-permeable character, leading to cell death [56].…”