Spatial and temporal distribution of free and conjugated estrogens during soil column transport

Endocrine disrupting chemicals (EDCs) are detected in environmental matrices such as surface water, wastewater, groundwater, and drinking water in the ng/L range. For environmental sediments, values in the range of ng/g and even lower are reported. These almost omnipresent low concentrations of estrogens are of major concern, in particular as sorption parameters derived from laboratory investigations tend to imply the absence of estrogens in the natural environment. Very few studies consider the fate and transport of estrogens in column tests at environmentally relevant concentrations, including metabolite formation and sorption. Also, the effect of input concentration on hormone degradation is unclear. To close this gap, the estrogens 17a-estradiol (E2), estrone (E1), and the conjugated estrogen estrone-sulfate (E1-3S) were each injected into saturated, packed soil columns as pulses with subsequent analysis of soil and aqueous samples. The transformation pathway E2 to E1 and subsequently to E1-3S was verified in sandy clay loam soil from Bet Dagan, Israel. Furthermore, it was shown that (i) E2 is rapidly degraded in soil and transformed in soil to E1; (ii) E1 is subject to strong retardation by sorption; and (iii) E1-3S behaves almost conservatively and shows the lowest sorption and transformation potential.