摘要
Municipal effluents are known to impede the immune system of aquatic organisms. The purpose of this studywas to examine the immunotoxicity of urbanwastewaters before and after 6 treatment processes from 12 cities toward trout leucocytes. Freshly prepared trout leucocyteswere exposed to increasing concentrations of solid phase （C18） extracts ofwastewaters for24 hr at 15°C. Immunocompetencewasdetermined by following changes in leucocyte viability and the proportion of cells able to ingest at least one （immunoactivity） and at least three （immunoefficiency） fluorescent beads. The influentswere treated by sixdifferent treatment strategies consisting of facultative aerated lagoons, activated sludge, biological aerated filter, biological nutrient removal, chemically-assisted physical treatment and trickling filter/solid contact. Water quality parameters of thewastewaters revealed that the plants effectively removed total suspended solids and reduced the chemical oxygendemand. The results revealed that the effluents＇ immunotoxic propertieswere generally more influenced by the properties of the untreatedwastewaters than by the treatment processes. About half of the incoming influentsdecreased leucocyte viabilitywhile4 treatment plantswere able to reduce toxicity. The influents readily increased phagocytosis activity for 8/12 influentswhile itwasdecreased in4/12 influents. This increasewas abolished for4/12 of the effluents using treatments involving biological and oxidative processes. In conclusion, municipal effluents have the potential to alter the immune system in fish and more researchwill be needed to improve the treatments ofwastewaters to better protect the quality of the aquatic environment.
Municipal effluents are known to impede the immune system of aquatic organisms. The purpose of this studywas to examine the immunotoxicity of urbanwastewaters before and after 6 treatment processes from 12 cities toward trout leucocytes. Freshly prepared trout leucocyteswere exposed to increasing concentrations of solid phase （C18） extracts ofwastewaters for24 hr at 15°C. Immunocompetencewasdetermined by following changes in leucocyte viability and the proportion of cells able to ingest at least one （immunoactivity） and at least three （immunoefficiency） fluorescent beads. The influentswere treated by sixdifferent treatment strategies consisting of facultative aerated lagoons, activated sludge, biological aerated filter, biological nutrient removal, chemically-assisted physical treatment and trickling filter/solid contact. Water quality parameters of thewastewaters revealed that the plants effectively removed total suspended solids and reduced the chemical oxygendemand. The results revealed that the effluents＇ immunotoxic propertieswere generally more influenced by the properties of the untreatedwastewaters than by the treatment processes. About half of the incoming influentsdecreased leucocyte viabilitywhile4 treatment plantswere able to reduce toxicity. The influents readily increased phagocytosis activity for 8/12 influentswhile itwasdecreased in4/12 influents. This increasewas abolished for4/12 of the effluents using treatments involving biological and oxidative processes. In conclusion, municipal effluents have the potential to alter the immune system in fish and more researchwill be needed to improve the treatments ofwastewaters to better protect the quality of the aquatic environment.
基金
supported by the St-Lawrence Action plan
