Experimental determination of bioconcentration of the nonionic surfactant alcohol ethoxylate

Alcohol ethoxylate (AE) is the most widely used nonionic surfactant in hous ehold detergents. Here we present compound-specific bioconcentration data f ur AE constituents determined in flow-through experiments. Values of the bi oconcentration factor (BCF) and the rate constants of uptake (k(1)) and eli mination (k(2)) in fathead minnows (Pimephales promelas) ranged between <5 and 390 L/kg, 330 and 1,660 L/kg/d, and 3.3 and 59/d, respectively. The hig h values of k(2) suggested rapid biotransformation of AE. As a consequence, AE was not stored inside the fish, and no relationship between the BCF and the lipid content was observed. The influence of both the alkyl and the et hoxylate chain length was studied. The BCF as well as k(1) increased with i ncreasing length of the alkyl chain and decreasing length of the ethoxylate chain. In contrast, a decrease of ii, with increasing alkyl chain length a nd decreasing ethoxylate chain length was found. Using structure-bioconcent ration relationships, the bioconcentration potential of an AE mixture was e stimated to be 140 L/kg. The bioconcentration potential of AE termed to be largely unaffected by processes occurring during wastewater treatment.