Occurence and Vertical Transport of Endocrine Disrupting Compounds in a Wastewater Spray Irrigated System.

The estrogens 17 β-estradiol (E2), estrone (E1) and 17 a-ethynlestradiol (EE2) are ranked among the most potent endocrine disrupting compounds (EDCs) due to their adverse effects in aquatic species at extremely low (ng/L) levels. Due to the inadequacy of treatment technologies, wastewater discharge from sewage treatment plants is a major source of environmental E1, E2 and EE2 worldwide. Being lipophilic (log Kow 2.5 – 4.0), estrogens have a tendency to sorb to soil organic matter. Thus, irrigation of treatment plant effluents has been proposed as a good management strategy for reducing estrogen levels in aquatic systems where their adverse effects have been widely recorded. Preliminary studies have detected E1 and EE2 in well water and soil sampled from the Pennsylvania State University’s (PSU) wastewater spray-irrigated system. However, no information is available on the occurrence and mobility of these estrogens in the Pennsylvania State University’s living filter system. This study aims to evaluate the extent to which wastewater effluent irrigation reduces or eliminates the entrance of E1, E2 and EE2 into groundwater. The leaching patterns of E1, E2 and EE2 through the PSU living filter system is investigated using batch and soil column studies. Using batch studies, the distribution coefficient (Kd) of each of the three estrogens are determined for each soil horizon within 75 cm depth samples. The residence time of each estrogen is estimated using the Kd values found and previously determined residence time of water. Leachate collected from 6 m and 12 m deep lysimeters are also analyzed for E1, E2 and EE2 levels to determine E1, E2 and EE2 occurrence in the living filter system.