Quantification of Estrogen Concentration in Cibolo Creek Receiving Wastewater Treatment Plants (WWTP) Effluent

Presence of estrogen compounds in aquatic environment and drinking water is a potential threat to aquatic organisms and human health. Estrogen contamination could be an issue in Cibolo Creek receiving effluents from two wastewater treatment plants (WWTP). Water samples from upstream and downstream of Cibolo Creek receiving effluent from WWTP were used to investigate natural estrogen (E2) and synthetic estrogen (EE2) prevalence in the stream as a function of distance travelled from the WWTP. Water samples were also collected from a spring input. The ELISA estrogen test-kit procedure was used for analyzing E2 and EE2 (ng L-1) in water samples collected bi-monthly during the summer of 2018. The mean E2 and EE2 concentration of the WWTP effluent were significantly different from concentrations in Cibolo Creek upstream of WWTP discharge points (p ≤ 0.05, ANOVA), indicating higher estrogen concentration in WWTP effluent compared to flow from Cibolo Creek upstream. The spring had the highest mean E2 concentration (0.0479 ng L-1), indicating potential contamination of shallow groundwater. Both E2 and EE2 concentration decreased downstream from the point of treated wastewater effluent discharge, whereas discharge did not increase, indicating a chemical or biological degradation of estrogen compounds. Nonetheless, the presence of E2 and EE2 at detectable levels suggests potential negative health effects on organisms inhabiting Cibolo Creek. A better understanding of the biological effects of estrogen compounds especially testing for vitellogenin and feminization in male fish inhabiting Cibolo Creek is essential to determine the possible adverse effects of estrogen compounds in streams receiving WWTP effluent.