Sorption and degradation of 17β-estradiol-17-sulfate in sterilized soil-water systems

Abstract

To identify abiotic processes that govern the fate of a sulfate conjugated estrogen, 17β-estradiol-17-sulfate (E2-17S), soil batch experiments were conducted to investigate the dissipation, sorption, and degradation of radiolabeled E2-17S under sterilized conditions. The aqueous dissipation half-lives (DT50) for E2-17S ranged from 2.5 to 9.3h for the topsoil of high organic carbon (OC) content (1.29%), but E2-17S remained at ∼80% of applied dose in the low OC (0.26%) subsoil by 14 d. The non-linear sorption isotherms indicated limited sorption of E2-17S, and the concentration-dependent log KOC values were 2.20 and 2.45 for the topsoil and subsoil, respectively. Additionally, two types of hydroxyl E2-17S (OH-E2-17S and diOH-E2-17S) were found as major metabolites in the aqueous phase, which represented 9-25% and 6-7% of applied dose for the topsoil and subsoil at 14 d, respectively. Free estrogens, 17β-estradiol (E2) and estrone (E1), were detected from the sorbed phase of the soil-water systems.

Keywords: 17β-Estradiol-17-sulfate; Deconjugation; Estrogen conjugate; Hydroxylation; Sorption.