The persistence of steroidal estrogens in the aquatic environment

Abstract

The presence and fate of the steroidal estrogens, estrone (E1), 17beta-estradiol (E2) and 17alpha-ethinylestradiol (EE2), in Ottawa and Cornwall wastewater treatment plants (WWTP's), drinking water, and the river water used as the drinking water source, were identified. Estrogens were extracted using accelerated solvent extraction, gel permeation chromatography and solid phase extraction, and identified using gas chromatography-mass spectrometry and internal C-13 standards. E1, E2 and EE2 concentrations ranged from 1.8 to 370, 24.3 to 66.9 and 0.4 to 9.8 ng L-1, respectively, and were affected by weather variables such as temperature and precipitation, and WWTP parameters such as daily flow and carbonaceous biochemical oxygen demand. Photodegradation rate constants under ultraviolet B radiation for E1 were directly proportional to radiation intensity and sample thickness, and inversely proportional to dissolved organic carbon concentration, but EE2 was remarkably persistent. A luciferase reporter gene assay found estrogenicity in both sewage effluent and UVB-exposed samples of estrogens, contributed by the degradation products of steroidal estrogens. Finally, EE2 persistence was also seen in a time-course experiment in which goldfish were exposed to 25 ng L-1 EE2. A mass-balance model calculated a bioconcentration factor (BCF) for EE2 in fish blood of 1400, whereas measured data revealed a maximum BCF of only 500.