Fate of Steroidal Hormones During Soil‐Aquifer Treatment

Abstract

AbstractThere is increasing concern that endocrine disrupting compounds such as steroidal hormones present in treated waste water effluents can affect ground water quality where waste water is used to recharge local ground water. Little is known how efficiently steroidal hormones are removed or transformed during percolation through the subsurface. The scope of this study was to examine the fate of hormones during soil‐aquifer treatment (SAT) leading to ground water recharge in controlled laboratory soil‐column studies and at two water reuse field sites where treated waste water is fed to ground water recharge basins. The selected steroidal hormones represented estrogens (17β‐estradiol and estriol) and androgens (testosterone). Composite samples of treated waste water and from ground water monitoring wells were collected and analyzed for steroidal hormones using enzyme‐linked immunosorbent assays. The study revealed that the mobility of the selected hormones in subsurface systems was low, and estriol and testosterone were both not detected (< 0.6 ng/L) in ground water monitoring wells or shallow lysimeters representing water samples after 1.5 m of travel through porous media. 17β‐estradiol, however, was consistently detected at concentrations < 2 ng/L in monitoring wells after travel of 1.5 m through porous media. Results from field sites that have been operational for more than 13 years indicated no breakthrough of the target compounds in ground water samples collected downstream of the surface spreading operation. These findings were confirmed by controlled laboratory studies simulating SAT in soil‐column experiments. It appeared that the majority of attenuation was due to adsorption of the three target compounds to the porous media matrix, and additional attenuation to below the detection limit occurred due to the presence of bioactivity regardless of dominating redox conditions (aerobic vs. anoxic) or the type of organic carbon matrix present (hydrophobic acids, hydrophilic carbon vs. colloidal carbon).