SORPTION OF MALE HORMONES BY SOILS AND SEDIMENTS

摘要

This paper reports the sorption of two male hormones, testosterone and androstenedione, by four soil and sediment samples at both equilibrium and rate-limiting conditions. Unlike prior studies, androstenedione was studied independently of testosterone. Apparent sorption equilibrium is achieved in one to two weeks when the initial aqueous hormone concentrations (C_o) at 10,000 μg/L (-30% of their solubility limits [S_w]) and two to three weeks when the C_o is 300 μg/L (less than 1% of S_w). The Freundlich model parameter n ranged from 0.698 to 0.899 for all soil-solute systems indicating nonlinear sorption isotherms. Isotherm nonlinearity leads to an inverse correlation between single-point organic carbon-normalized sorption distribution coefficients (K_(oc)) and equilibrium androgen concentration (C_c). When C_c/S_w = 0.012, the log K_(oc) values for testosterone and androstenedione on the various sorbents ranged from 6.18 to 6.75 and 6.83 to 6.04, respectively, compared to 6.30 to 6.80 and 6.16 to 6.92 when C_e/S_w = 0.004. This study suggests that male hormones may exhibit slow rates of sorption over 14 d or longer and that soils and sediments may have greater sorption distribution coefficients when concentrations fall into the ng/L range.