Ecotoxicological characterization of surface water, groundwater, and leachate from a sanitary landfill.

Improper disposal of such waste represents a serious threat to the environment due to its potential to contaminate soil, rivers, and oceans, thereby endangering biota and public health. This study aimed to evaluate the ecotoxicological effects of raw and treated leachate, as well as surface water and groundwater adjacent to a Class II landfill, on germination and early growth parameters of Allium cepa L. and the viability or survival of Aliivibrio fischeri. The tested sample concentrations were 25, 50, 75, and 100%, each diluted in distilled water. In the phytotoxicity assays, A. cepa seeds were exposed to different sample concentrations, with distilled water serving as a negative control. The analyzed parameters included germination percentage, germination speed index, shoot length, root elongation, mitotic index, and chromosomal abnormalities. In the acute toxicity tests, the effect on bacterial luminescence was evaluated. Surface water and groundwater samples did not induce toxicity in A. cepa seeds, whereas raw and treated leachate samples inhibited germination and consequently negatively affected all other evaluated parameters. In A. fischeri assays, leachate samples exhibited toxicity, while surface water and groundwater samples induced a hormesis effect. The results from adjacent water samples demonstrate the landfill's efficiency in mitigating contamination of water bodies.