Monitoring natural and synthetic estrogens at activated sludge sewage treatment plants and in a receiving river water

Sewage treatment plant (STP) effluents with primarily domestic inputs are s trongly suspected to be an important source of natural and synthetic estrog ens contaminating the aquatic environment. Even a few ng/L of some of these substances can provoke reproductive disturbances in riverine fish. The mai n purpose of this investigation has been that of ascertaining whether activ ated sludge STPs (ASSTPs) are able to produce significant amounts of free e strogens. For this purpose, we have monitored monthly estriol (E-3), estrad iol (E-2), estrone (E-1) and ethinylestradiol (EE2) in influents and efflue nts of six Roman ASSTPs for five months. To do this, we have developed an o riginal analytical method involving analyte extraction with a Carbograph 4 cartridge and LC coupled with negative turbo ion spray tandem mass spectrom etry in the selected reaction monitoring mode. Analyte recovery ranged betw een 86 and 91%, and limits of quantification were below 1 ng/ L. Over five months, inlet concentrations of E-3, E-2, E-1 and EE2 at the six plants ave raged respectively 80, 12, 52 and 3.0 ng/L. On the basis of the daily human excretion of conjugated estrogens, the above values suggest that deconjuga tion oc curs preferentially in sewers. The activated sludge treatment effic iently removed E-3 (95%), E-2 (87%), EE2 (85%), but not E-1 (61%). In four events out of thirty, E-1 outlet levels were even larger than inlet levels. Median concentrations of the two most potent estrogens, that is E-2 and EE 2 leaving the six ASSTPs were respectively 1 and 0.45 ng/L. Ana lysis of a river (Tiber) water sampled downstream of small towns whose sewages are tre ated by percolating filter STPs or directly discharged into the river revea led the presence of all four estrogens at levels between 0.04 (EE2) and 1.5 ng/L (E-1).