Natural and birth control estrogens excreted by humans and xenoestrogens such as detergents and plasticizers that enter streams from wastewater treatment plants (WWTP) cause endocrine disruption in fish.  The Lopatcong Creek in Phillipsburg, NJ had previously been shown to have elevated levels of estrogenic activity below the Philipsburg WWTP effluent outfall.  We used transgenic yeast to determine if the elevated estrogenic levels downstream were high enough to cause a measurable increase in estrogenic activity in the tissues of downstream fish.  Estrogenic chemicals are removed from the blood by the liver and are concentrated in the bile.  Previous studies had shown elevated estrogenic activity in the bile of several species of fish taken from waters with elevated estrogenic activity.  We measured estrogenic activity of decongugated fish bile with a strain of brewer’s yeast, Saccharomyces cerevisiae, that had been genetically modified by the insertion of the human estrogen receptor gene and the reporter lac-Z operon.  The yeast could detect as little as 10 parts per trillion of natural estrogen.  American eels (Anguilla rostrata) were collected  in the Lopatcong Creek by electroshocking above and below the WWTP effluent outfall in October 2007. 

Results/Conclusions

The median estrogenic activity in the bile of the 5 eels collected below the outfall (280 parts per billion) was 5 times greater (p<0.02) than the median estrogenic activity of the 9 eels collected above the WWTW outfall (56 ppb).  This research provides insight into the presence of estrogenic compounds in a high quality stream and suggests that fish populations below the WWTP outfall may be negatively affected.  .