Assessing the Occurrence, Persistence, and Fate of Natural and Synthetic Steroid Estrogens in Vernal Pools

Abstract:

The presence of natural and synthetic estrogens in treated wastewater used for irrigation of agricultural fields poses a potential risk to surface water ecosystems. While a large number of recent studies have investigated the occurrence, fate, and transport of estrogens in the environment, the vast majority of these studies have focused on the fate of estrogens in streams and rivers. However, no studies have been conducted assessing the occurrence, persistence, and fate of estrogens in impacted sensitive aquatic ecosystems such as vernal pools. This is of particular importance because vernal pools serve as critical breeding habitat for amphibians, which are known to be sensitive to the presence of endocrine disrupting compounds. A spray irrigation system was implemented over 50 years ago at Penn State’s “Living Filter” as an alternative to discharging treated wastewater to a high quality trout stream. This system introduces all of Penn State’s treated wastewater onto approximately 250 ha of agricultural and forested land at a rate of ~5 cm/ha/week. More than a dozen vernal pools are impacted by this wastewater irrigation, with some ponds adjacent to irrigation laterals receiving direct inputs of the treated wastewater. The goal of this study was to assess the impact of these weekly irrigation activities on the occurrence, persistence, and fate of estrogens (17α- and 17β-estradiol, estrone, estriol, and ethinylestradiol) in 3 vernal pools during an 8-week field study. The spring 2015 study period coincided with wood frog breeding and metamorphosis. Irrigation wastewater was collected weekly and water samples near the sediment-water interface in each vernal pool were collected daily. Real-time monitoring stations continuously recorded the temperature, pH, redox potential, DO, EC, and water level at each pool. Nearly 100% of the daily samples (n>130) collected contained estrogens, and the concentrations were several times higher compared to the wastewater. Additionally, the data suggest transformation of estrone back to 17α- and 17β-estradiol potentially due to anaerobic conditions in the vernal pools. This unique field study suggests that more research is needed to quantify the potential impact of estrogenic activity on amphibians, particularly during the critical metamorphosis period.