The endocrine disrupting activity of surface waters and of wastewater treatment plant effluents in relation to chlorination

The mean EEQs were 5.0 ng/L ( ± 6.1 ng/L) upstream of the plant, 6.7 ng/L ( ± 7.4 ng/L) downstream from the plant and 23.3 ng/L ( ± 20.4 ng/L) in the WWTP effluent. The difference between upstream and downstream of the treatment plant was not significant. Chlorinated water samples had lower estrogenic activity and E. coli concentrations, but had greater toxicity and higher trihalomethane concentrations. Estrogenic activity was not correlated with toxicity. These results suggest that the WWTP effluent had little impact on the estrogenic activity of the recipient river.