This peer-reviewed study assessed (anti)estrogenic activity in South African wastewater treatment works and receiving surface waters, evaluating the reliability of different bioassay methods for environmental monitoring. Samples from wastewater influent, effluent, and downstream river systems were analysed to determine the presence of endocrine-disrupting compounds (EDCs) capable of mimicking or inhibiting natural estrogen activity.

Results confirmed measurable estrogenic and anti-estrogenic activity at various stages of treatment, with reductions observed through treatment processes but persistent activity detected in some receiving waters. The study highlights the importance of integrating effect-based bioassays with chemical analysis to strengthen monitoring programmes, improve risk assessment, and support more robust wastewater management strategies.