17β-Estradiol and Testosterone Sorption in Soil with and without Poultry Litter

17 beta-estradiol and testosterone are naturally occurring steroids that co-occur in poultry litter. The effects of litter on sorption of these hormones to soil are not known. Sorption isotherms were developed for C-14-labeled testosterone and H-3-labeled estradiol in a Cecil sandy clay loam with and without poultry litter addition. The effect of applying the hormones alone (single-sorbate) or together (multisorbate) was also investigated. C-14-testosterone sorption in soil increased from 2 to 48 h and remained relatively constant thereafter. H-3-estradiol sorption in soil was relatively constant from 2 to 24 h and then decreased to 72 h. These differences may reflect transformation of the parent hormones to products with different solid-phase affinity. The maximum sorption coefficient (K-d) in soil for C-14-testosterone (20.2 mL g(-1)) was similar to that for H-3-estradiol (19.6 mL g(-1)) in single-sorbate experiments. When hormones were applied together, sorption of both hormones in soil decreased, but the C-14-testosterone K-d (12.5 mL g(-1)) was nearly twice as large as the H-3-estradiol K-d (7.4 mL g(-1)). We propose this resulted from competition between the hormones and their transformation products for sorption sites, with C-14-testosterone and its expected transformation product (androstenedione) being better competitors than H-3-estradiol and its expected transformation product (estrone). When poultry litter was mixed with soil, sorption increased for H-3-estradiol but decreased for C-14-testosterone. This may have been because poultry litter slowed the transformation of parent hormones. Our results show that poultry litter could have important effects on the mobility of estradiol and testosterone.