title: Dissipation and transformation of 17β-estradiol-17-sulfate in soil-water systems.
abstract: In the environment, estrogen conjugates can be precursors to the endocrine-disrupting free estrogens, 17β-estradiol (E2) and estrone (E1). Compared to other estrogen conjugates, 17β-estradiol-17-sulfate (E2-17S) is detected at relatively high concentrations and frequencies in animal manure and surface runoff from fields receiving manure. To elucidate the lifecycle of manure-borne estrogens and their conjugates in the environment, the fate of radiolabelled E2-17S in agricultural soils was investigated using laboratory batch studies with soils of different organic carbon (OC) content (1.29% for topsoil versus 0.26% for subsoil). E2-17S was found relatively persistent in the aqueous phase throughout the duration of the 14 d experiment. The aqueous E2-17S persisted longer in the subsoil (half-lives (DT₅₀)=64-173 h) than the topsoil (DT₅₀=4.9-26 h), and the aqueous persistence of E2-17S depended on its initial concentration. The major transformation pathway was hydroxylation, yielding mono- and di-hydroxy-E2-17S (OH-E2-17S and diOH-E2-17S). Free estrogens, E2 and E1, were only observed in the sorbed phase of the soil at low concentrations (∼1% of applied dose), which demonstrated that deconjugation and subsequent oxidation had occurred. Although deconjugation was not a major pathway, E2-17S could be a precursor of free estrogens in the environment.
authors.affiliation: Department of Soil Science, North Dakota State University, Fargo, ND 58108-6050, USA.
authors.forename: Xuelian
authors.initials: X
authors.lastname: Bai
authors.forename: Francis X M
authors.initials: FX
authors.lastname: Casey
authors.forename: Heldur
authors.initials: H
authors.lastname: Hakk
authors.forename: Thomas M
authors.initials: TM
authors.lastname: DeSutter
authors.forename: Peter G
authors.initials: PG
authors.lastname: Oduor
authors.forename: Eakalak
authors.initials: E
authors.lastname: Khan
mesh_terms: D000383:Agriculture / Q000379:methods; D000818:Animals; D002244:Carbon / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods; D004958:Estradiol / Q000031:analogs & derivatives* / Q000737:chemistry; D004967:Estrogens / Q000737:chemistry; D006868:Hydrolysis; D006900:Hydroxylation; D007700:Kinetics; D008372:Manure; D013058:Mass Spectrometry; D010100:Oxygen / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000302:isolation & purification*; D012997:Solvents / Q000737:chemistry; D013552:Swine; D013997:Time Factors; D014873:Water Pollutants / Q000032:analysis / Q000302:isolation & purification*
chemical_list: D004967:Estrogens; D008372:Manure; D012989:Soil Pollutants; D012997:Solvents; D014873:Water Pollutants; C048615:estradiol 17-sulfate; D004958:Estradiol; D002244:Carbon; D010100:Oxygen
keywords: 17β-Estradiol; 17β-Estradiol-17-sulfate; Deconjugation; Estrogen; Estrogen conjugate; Hydroxylation