Functional estrogenic activity in rivers, water supply, and rainwater

Estrogenic endocrine-disrupting chemicals (eEDCs) are a significant concern due to their widespread contamination of water sources and their potential to disrupt both human and ecological health. Currently, the assessment of EDC contamination focuses on detecting a limited number of targeted compounds that serve as proxies for broader chemical exposure .As a result, the true extent of the risk remains unknown. This study describes the development and application of a novel cell-free in vitro transcription (IVT)-based reporter gene assay for detecting estrogenic activity in water sourced from natural water bodies, drinking water (including filtered fountains and household supply), tank water, rainwater, and bottled water. Using estradiol (E2)-spiked water samples across the range 0.1362-1362 pg/mL, the assay demonstrated high sensitivity with a detection limit of 1.0 pg/mL. When applied to natural riverways, drinking, tank and rain waters, the results revealed significant estrogenic activity across all tested water sources, with E2 equivalence ranging from 2 pg/L to 69 mg/Lin natural water bodies. Bottled water samples also showed varying degrees of estrogenic activity (0-4 ng/L). This study underscores the urgent need for improved monitoring tools like the IVT assay, which are easy to use and capable of detecting the cumulative estrogenic effects of complex EDC mixtures. Employing such tools provides a more comprehensive view of contamination revealing broader human and environmental risks posed by these compounds.