Occurrence and Risk Assessment of Estrogenic Hormones in Natural and Drinking Water Systems: An Integrative Review

Estrogenic hormones (EHs), including estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2), are recognized endocrine disruptor compounds that impact aquatic organisms and human health at low concentrations. Although their occurrence in water systems is well documented, regulatory benchmarks remain limited. This study presents an integrative review of EH concentrations in surface ( n = 145) and drinking water ( n = 27) worldwide, alongside a risk assessment based on biological assay data (no-observed-adverse-effect level/lowest-observed-adverse-effect level). Predicted no-effect concentration (PNEC) was calculated at 0.01 ng/L for E1 and E2 and 0.001 ng/L for EE2. Drinking water equivalent levels for human health were established at 0.007 ng/L for E1 and E2 and 0.0007 ng/L for EE2, highlighting that existing water treatment systems may not consistently reduce EH concentrations to levels considered safe for long-term exposure. The results emphasize the need for advanced water treatment technologies, broader monitoring programs, and the establishment of health-based regulatory standards. By proposing reference values and consolidating global occurrence data, this review supports the development of improved management strategies for water quality and public health.