The leachates are the seat of complex processes which give them a heterogeneous character. Their compositions vary according to several factors: nature of the waste, conditions of their deposition, climatic conditions, their durations of stay, etc. They contain important quantities of organic, mineral matters even of bacteria, which require their treatment in order to safeguard the environment. To do this, several methods are used, such as membrane techniques (reverse osmosis, nanofiltration, etc.), biological techniques (activated sludge, SBR, etc.) and physicochemical techniques (Coagulation-flocculation, adsorption on activated carbon, etc.). Among these techniques, the leachate treatment by coagulation process with the lime showed interesting reduction of the various pollutants: 92.95% of turbidity, 88.23% of suspended matter, 89.89% of COD, 90.83% of BOD5, 78.39% of Fe, 77.78% of Mo, 38.29% of Cd, 48.75% of Al, 50.24% of S 2− , 20.57% of K + , 27.24% of phosphorus and 19.53% of Cl −. Based on these results, the coagulation with the lime reveals interesting because it allows to reduce at a lesser cost the pollutants present in leachates.

World wide application of pesticide has drastically increased during the last two decades resulting with the changes in farming practices and enormously increasing intensive agriculture. This wide application of pesticides has resulted in the presence of their residues in various environmental matrices. It’s environmental tenacious, hoarding and their impacts in the ecosystem was incompetently perceive. These chemicals will finally enters into the aquatic system. Their lower persistent and soluble nature of many pesticide will impart their major portion to fishes, so the aim of the present study was the assessment of residues in water and fishes of the aquatic system it will throw back the present status of accumulation pesticides in the ecosystem. Result of the analysis showed that the fishes from the various study locations are fit for domestic consumptions, as the samples studied did not indicate any adverse or extremely high pesticide content that may affect the health of those consuming the fishes.