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Sorption of steroid estrogens to soil and soil constituents in single‐ and multi‐sorbate systems
Author(s) -
Bonin Julia L.,
Simpson Myrna J.
Publication year - 2007
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/07-118.1
Subject(s) - sorption , freundlich equation , environmental chemistry , chemistry , soil water , langmuir , estrone , organic matter , soil science , adsorption , organic chemistry , geology , biochemistry , hormone
The sorptive behavior of 17 β‐estradiol (estradiol), estrone, and 17α‐ethinylestradiol (EE2) from aqueous solutions to four soil samples, two clay minerals, and sand was examined. The measured sorption isotherms were found to be nonlinear and soil isotherm data fit the Freundlich model. Alternatively, both the Langmuir and Freundlich models were used for the mineral samples. The sorption affinity of steroid estrogens was found to be greater for montmorillonite than kaolinite and the sand. The soil Freundlich coefficients ( K F ) for estradiol, estrone, and EE2 were observed to increase with organic carbon (OC) content, and resulting Freundlich coefficients that were normalized to the OC content ( K F OC) were observed to be within the same range for estradiol and estrone but not for EE2. Sorption of steroid estrogens in soil appears to be governed by OC and expanding clay mineral content; thus, estimating sorption coefficients from physicochemical properties may underestimate sorption in soils or sediments that are rich in OC and smectitic clay minerals. Analysis of soils by solid‐state 13 C nuclear magnetic resonance did not reveal any trends between sorption capacity and organic matter structure. Competitive sorption experiments revealed that the degree of competition varied with the OC and mineral content, further suggesting that specific soil properties are important for understanding sorption of estrogens in terrestrial environments.