Dissipation of part per trillion concentrations of estrogenic hormones from agricultural soils

Abstract

Estrogenic hormones can affect fish at extremely low aquatic concentrations. A study was therefore undertaken to determine if agricultural soils, which can receive steroidal estrogenic hormones via livestock, poultry or municipal biosolids, could dissipate ng kg-1 soil concentrations of 17ß -estradiol or 17α-ethynylestradiol. Incubations with [4-14C]-17ß-estradiol, [6,7-3H(N)]-17ß-estradiol and [6,7-3H(N)]-17α-ethynylestradiol revealed that the major pathway of hormone dissipation was formation of soil-bound, non-extractable residues. The dissipation kinetics and pathways of both these compounds at these very low concentrations were entirely consistent with those previously observed at 1000-fold higher concentrations. We conclude that, in the absence of preferential or surface flow, very low concentrations of hormones can be expected to be dissipated, and the risk of contamination of water adjacent to agricultural soils treated with estrogen-containing biosolids during a temperate growing season is likely to be low. Key words: Endocrine disrupting chemical, soil, 17β-estradiol, 17α-ethynylestradiol, biodegradation