Detection, fate and transport of estrogen family hormones in soil

Estrone (E1), 17β-estradiol (E2), and estrone-sulfate (E1-3S) are released into the environment in significant amounts. They are known to adversely affect the endocrine systems of aquatic organisms. Although previous studies clearly demonstrate that free hormones sorb strongly to soil and degrade quickly, significant amounts of free and the more persistent conjugated estrogens can be still detected in various environmental media. To date, E1-3S has been considered as a metabolite that forms either during the animal hormone cycle or as a degradation product of precursor hormones like E2-3S. We performed small-scale laboratory column tests to investigate two major features: transport and degradation of E2, and formation of E1-3S and E1. To evaluate the influence of soil microbial activity, one portion of soil was autoclaved and the background solution treated with sodium azide. The results demonstrate that (i) E2 is degraded to E1 and E1-3S in non-autoclaved soil, and to E1 in autoclaved soil, (ii) the formation of E1-3S is biologically driven, and (iii) the transformation of E2 to E1 does not require biological interaction. An inverse modeling approach was used to quantify the transport parameters and degradation rate coefficients.