Ecotoxicological characterization of a disposal lagoon from a munition plant

Sediment samples were collected at several locations in an unlined wastewater-disposal lagoon of a munitions plant in Argentina, and concentrations of total petroleum hydrocarbons, 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, and nitrocellulose were determined. Counts of anaerobic heterotrophic microorganisms were quantified also, and the effects of the sediments on earthworms Eisenia fetida were examined. Concentrations of total petroleum hydrocarbons and 2,4,6-trinitrotoluene ranged 0 313 g/kg and 0 800 mg/kg, respectively. In the earthworm bioassay, survival was inhibited in a dose-dependent manner. The sensitivity of the earthworm bioassay was low compared with the microbiological assay, and microscale bioremediation assays revealed that the growth of endogenous flora was limited by the low phosphorus content of the sediment. However, the presence of microorganisms in all sediment samples suggested that, if isolated, indigenous microflora could be adapted for remediation.