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摘要
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 [C-14]TCC or [C-14]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. Environ. Toxicol. Chem. 2010;29:1925-1933.
- 出版日期2010-9
