title: Comparing the presence, potency, and potential hazard of genotoxins extracted from a broad range of industrial effluents.
abstract: We examined the genotoxicity of dichloromethane extracts from 50 final effluent samples collected from 42 industries, including pulp and paper, chemical manufacturing, metal refining, metal surface treatment, and municipal waste water treatment. Effluents were initially fractionated into dissolved substances, and substances adsorbed to suspended particulate matter. Acid/base partitioning was used to further fractionate aqueous extracts. Genotoxicity of extracts was found to be related to sample type, industry type, metabolic activation status, and extract fluorescence (380 nm excitation, 430 nm emission). S9 metabolic activation reduced genotoxic potency in over 90% of the extracts examined. Expression of potency values per equivalent unit of original sample revealed that effluent particulate matter is, on average, almost four orders of magnitude more potent than aqueous filtrates. Suspended particulate matter from organic and inorganic chemical production, petroleum and metal refining, and from metal surface treatment facilities, provided extracts that were significantly more genotoxic than those from sewage treatment and pulp and paper facilities. Aqueous filtrates from inorganic and organic chemical production, metal refining, and surface treatment facilities were significantly more genotoxic than those emitted by aluminum and petroleum refineries. Overall, the results suggest that pulp and paper mills emit mostly soluble genotoxins, while petroleum and aluminum refineries emit predominantly particle-associated genotoxins. Although some extracts elicited a strong SOS response, the potency of the extractable residues was low when compared to highly potent pure substances such as benzo(alpha) pyrene. On average, a mg of dichloromethane-extractable residue has an SOS genotoxicity equivalent to 0.1-1.0 microg of benzo(alpha) pyrene. Predicted Ames mutagenic potency values corresponded reasonably well with industrial waste mutagenic potency values corresponded reasonably well with industrial waste mutagenic potency values published by other researchers. Genotoxic loading values were calculated to quantify the total daily genotoxic emission and potential hazard of each industry. Highest loadings were from sewage treatment, pulp and paper, and metal refining facilities. Highest loading values were the SOS genotoxic equivalent of over 30 kg of benzo(alpha)pyrene per day. The ultimate hazard of genotoxic emissions is not known. Actual hazard assessment is complicated by a poor understanding of the postemission behavior of genotoxins. Exposure of downstream biota is likely substantial.
authors.affiliation: Department of Biology, McGill University, Montreal, Canada.
authors.forename: P A
authors.initials: PA
authors.lastname: White
authors.forename: J B
authors.initials: JB
authors.lastname: Rasmussen
authors.forename: C
authors.initials: C
authors.lastname: Blaise
mesh_terms: D000704:Analysis of Variance; D001564:Benzo(a)pyrene / Q000633:toxicity; D001711:Biotransformation; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure; D007220:Industrial Waste / Q000009:adverse effects*; D008670:Metals / Q000633:toxicity; D008752:Methylene Chloride; D009152:Mutagenicity Tests; D009153:Mutagens / Q000633:toxicity*; D009154:Mutation / Q000187:drug effects* / Q000235:genetics; D013014:SOS Response, Genetics / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D013223:Statistics as Topic
chemical_list: D007220:Industrial Waste; D008670:Metals; D009153:Mutagens; D001564:Benzo(a)pyrene; D008752:Methylene Chloride