A pilot survey of 39 Victorian WWTP effluents using a high speed luminescent umu test in conjunction with a novel GC-MS-database technique for automatic identification of micropollutants

Abstract

In 2007, samples of treated effluent were collected at point of discharge to the environment from 39 wastewater treatment plants (WWTPs) located across Victoria, Australia grouped by treatment type. Sample genotoxicity was assessed with a high-throughput luminescent umu test method using Salmonella typhimurium TL210 strain, with and without addition of a commercially available metabolic activation system. Samples were also screened using a gas chromatographic—mass spectrometric mass-structure database recognition method. A genotoxic response was observed in half of the samples tested without metabolic activation system (<LOR – 0.19 μg/L 4-nitroquinoline-N-oxide equivalents). On addition of metabolic activation system, 75% of samples elicited a genotoxic response, the majority of responses were stronger than without metabolic activation (<LOR – 2.97 μg/L benzo[a]pyrene equivalents). The type of WWTP had no effect on genotoxicity. A large number of chemicals were identified in the effluents, although none could be unambiguously tied to the genotoxicity observed. Chemicals observed in one or more effluents included food additives (e.g. dibenzylether), various alkyl phenols, tyre leachates (e.g. 2(3H)-benzothiazolone), antioxidants, flame retardants (e.g. tris(2-chloroethyl)phosphate), insect repellents (e.g. diethyltoluamide), stimulants (e.g. caffeine) and anticonvulsants (e.g. carbamazepine). Of the 451 pesticides screened, carbamate insecticides (e.g. bendiocarb, propoxur), plant growth regulators (e.g. propham) and herbicides (e.g. atrazine, metolachlor, simazine) were amongst the compounds observed.