Bisphenol-A in artificial indoor streams: I. Fate and effects on aufwuchs.

The disappearance (DT50) from water-phase and effects on aufwuchs of three nominal concentrations (5, 50 and 500 microg/l) of bisphenol-A (BPA) were investigated in artificial indoor streams over a period of 103 days. HPLC was used for analyses of BPA in water. Because of the disappearance of BPA from the water-phase, a pulse dosed exposure in weekly intervals was established. At the beginning of the exposure, a lag-phase of approximately 3-8 days was noted. Afterwards DT50 values (time, when 50% of initial BPA disappeared) were about 1 day with no clear trend to lower values during the experiment. The dynamics of aufwuchs was investigated on artificial substrates (unglazed ceramic tiles) in 14-day intervals and quantified by ash free dry weight (AFDW). As an ecotoxicological endpoint the area under the biomass/time curve (AUC) was calculated for: (a) the absolute AFDW-values and (b) values as percentage of start biomass (value of day-2 set as 100%). The reduction of AUC by 10% (EC10) and 50% (EC50) for absolute values was 11 microg/l (nominal: 38) and 46 microg/l (450), respectively; for values as percentage of start biomass: EC10 20 microg/l (239) and EC50 73 microg/l (806). These values are 20-70-fold lower compared to results from standard algae tests (EbC, 96 h).