ABSTRACT
The genotoxicity of river water and sediment including interstitial water was evaluated by microscreen phage-induction and Salmonella/microsome assays. Different processes used to fractionate the sediment sample were compared using solvents with different polarities. The results obtained for mutagenic activity using the Salmonella/microsome test were negative in the water and interstitial water samples analysed using the direct concentration method. The responses in the microscreen phage-induction assay showed the presence of genotoxic or indicative genotoxic activity for at least one water sample of each site analysed using the same concentration method. Similar results were obtained for interstitial water samples, i.e. absence of mutagenic activity in the Salmonella/microsome test and presence of genotoxic activity in the microscreen phage-induction assay. Metal contamination, as evidenced by the concentrations in stream sediments, may also help explain some of these genotoxic results. Stream sediment organic extracts showed frameshift mutagenic activity in the ether extract detected by Salmonella/microsome assay. The concentrates evaluated by microscreen phage-induction assay identified the action of organic compounds in the non-polar, medium polar and polar fractions. Thus, the microscreen phage-induction assay has proven to be a more appropriate methodology than the Salmonella/microsome test to analyse multiple pollutants in this ecosystem where both organic compounds and heavy metals are present.
Subject(s)
Bacteriophage lambda/physiology , DNA, Bacterial/drug effects , Metals, Heavy/toxicity , Salmonella typhimurium/drug effects , Virus Activation/drug effects , Water Pollutants, Chemical/toxicity , Water Pollution, Chemical/analysis , Animals , Bacteriophage lambda/genetics , Biotransformation , Brazil , DNA, Bacterial/genetics , Escherichia coli/drug effects , Escherichia coli/genetics , Escherichia coli/virology , Fresh Water , Genes, Bacterial/drug effects , Geologic Sediments/chemistry , Industrial Waste/analysis , Lysogeny , Male , Metals, Heavy/analysis , Metals, Heavy/isolation & purification , Microsomes, Liver/metabolism , Mutagenicity Tests , Rats , Rats, Sprague-Dawley , SOS Response, Genetics , Salmonella typhimurium/genetics , Solvents , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/isolation & purificationABSTRACT
The genotoxicity of river water samples was evaluated by the Salmonella mutagenicity assay and by the microscreen phage-induction assay. Different processes of sample treatment were compared using the following assays: different volumes of a non-concentrated sample (direct method); concentrated sample fractionated into portions with acid, basic and neutral activity (liquid-liquid extraction method); sample submitted to extraction of volatile substances (volatile extraction method). Samples that were positive to the Salmonella assay by the direct concentration method lost this activity after liquid-liquid extraction. This difference was related to the loss of substances that volatilize during the extraction process. The study of volatile product concentrates confirmed the role of these compounds in inducing activity present in some samples. The microscreen phage-induction assay proved to be a good screening assay for genotoxic compounds present in small concentration in environmental samples. We conclude that, whenever possible, samples should be treated by the direct method in different volumes to prevent the loss of genotoxic substances.
Subject(s)
Environmental Monitoring/methods , Mutagenicity Tests/methods , Mutagens/analysis , Water Pollutants/toxicity , Water Pollution, Chemical , Brazil , Chemical Industry , Environmental Monitoring/instrumentation , Evaluation Studies as Topic , Fresh Water , Petroleum , Salmonella/drug effects , Salmonella Phages/drug effects , Specimen HandlingABSTRACT
Aqueous extracts of seven species used in Brazilian popular medicine (Achyrocline satureoides, Iodina rhombifolia, Desmodium incanum, Baccharis anomala, Tibouchina asperior, Luehea divaricata, Maytenus ilicifolia) were screened to the presence of mutagenic activity in the Ames test (Salmonella/microsome). Positive results were obtained for A. satureoides, B. anomala and L. divaricata with microsomal activation. As shown elsewhere (Vargas et al., 1990) the metabolites of A. satureoides extract also show the capacity to induce prophage and/or SOS response in microscreen phage induction assay and SOS spot chromotest.
