Characterization of the chemical constituents and toxicity to aquatic organisms of a municipal landfill leachate

Samples of leachate were obtained at four locations in effluent streams from a municipal waste landfill near Halifax, Nova Scotia. Samples were analyzed for a number of physical and chemical parameters using standard laboratory procedures. Samples were also screened to identify organic chemicals by matching mass spectrometer output against a reference spectrum library. Static acute toxicity tests (48 h to 96 h) were also conducted on samples using rainbow trout (Oncorhynchus mykiss), brook trout (Salvelinus fontinalis) and water fleas (Daphnia magna) as test organisms. The acute toxicity of leachate was primarily due to its ammonia content; however, the chronic effects on aquatic organisms of the range of organic chemicals identified in these samples remains undetermined. Paradoxically, the leachate discharge to the receiving water body reduced the toxic potential of that water to the organisms tested.