Estrogen occurrence and persistence in vernal pools impacted by wastewater irrigation practices

Planned beneficial re-use of water has become an increasingly common conservation practice worldwide, sparking questions about the degree of water treatment needed to mitigate negative environmental impacts. Since the early 1980s, as an alternative to surface discharge, the Pennsylvania State University has spray-irrigated all of its treated wastewater effluent via land application onto an environmental setting known as the “Living Filter” site (∼245 ha). The impacts of spray irrigation on nearby ephemeral wetlands, known as vernal pools, were explored. The pools gain water from both natural rainfall and spray-irrigation of the University's treated wastewater. The occurrence and persistence of estrogens in three vernal pools were quantified by analyzing >137 water samples collected from the pools over an eight-week period coincident with the development period of native amphibian larvae. Additionally, dissolved oxygen, oxidation-reduction potential, water level, water temperature, electrical conductivity, pH, and rainfall data were measured continuously throughout the study period within each pool. Further, the treated wastewater effluent was sampled during each weekly spray-irrigation event. Estrone was detected in nearly 100% of the vernal pool samples, with concentrations up to 6.2 ng L⁻¹. Additionally, 17α-estradiol was not detected in the wastewater effluent, but was present in 52% of the vernal pool samples. 17β-estradiol, estriol, and 17α-ethinylestradiol were detected in fewer than 10% of the vernal pool samples. The findings of this research have important implications for management practices that can help protect these critical habitats.