Genotoxicity of aqueous elutions of industrial soils.

The genotoxicity of industrial soils was evaluated. A single cell electrophoresis assay or comet assay, using eleocyte cells of Eisenia foetida, was performed to assess the genotoxicity of aqueous elutions. These were obtained from industrial soils containing metals. All soil samples meet the environmental quality guidelines for metal concentrations. However, elutions have produced genotoxic effects at dilutions as low as 6%. Total metal concentrations for each aqueous elution could express synergistic effects of these compounds.

Risk assessment of domestic and industrial effluents unloaded into a freshwater environment.

An ecotoxicologic study was performed to assess the environmental status of the Lujan River. It is an important freshwater system in the northeast of Buenos Aires Province, Argentina. Surface waters (SWs) and liquids effluents (LEs), before they reached the river, and sediments were assessed via acute toxicity screening using a battery of tests with native species. Additionally, the presence, in each LE and SW sample, of bioaccumulatable compounds was checked by SPME extraction and gas chromatograph-MS determination. An environmental risk assessment of each LE was carried out via toxic units and assessment factors approach and through extrapolation methods. Hazardous concentrations for each LE were compared with their river effluent concentrations. Ninety-one percent (91%) of the total toxic load of the river was due to 4 of 11 LEs (37%) evaluated. Although SW samples were not toxic, a real environmental risk was found for this freshwater environment. Sediment toxicity was found to be related to the proximity to pipe discharges. Bioaccumulatable compounds were found in SWs and in LEs. Esters of phthalic acids, morpholine, hydroquinone, and nonylphenol were found throughout the river at different sample sites and in different months during the 1-year sampling program.

Effects of paraquat on mortality and cardiorespiratory function of catfish fry Plecostomus commersoni.

The effects of a paraquat commercial herbicide formulation on an early stage of the development of Plecostomus commersoni were evaluated. Mortality, opercular ventilation rate, cardiac contraction rate and body length and weight were examined every 12 hr. The effects of the paraquat formulation on the morphology of the branchial epithelium were also examined by light microscopy. The assayed paraquat formulation significantly affected cardiac contraction and opercular ventilation. Ecotoxicologically, this could represent an important deleterious effect for early development of the catfish. Mortality data may not be sufficient for an appropriate evaluation of secondary environmental hazards associated with the application of paraquat formulation because: a) The LC-50 values for Plecostomus commersoni fry were higher than the recommended individual application rate of paraquat for aquatic weed control (0.1-2.0 mg/L). b) The estimated maximum acceptable toxicant concentration (MATC) resulted in a concentration similar to the application rate when calculated from acute toxicity tests. When the MATC was estimated from opercular ventilation or cardiac contraction rates, it was lower and fell within the recommended single application rate.