Impacts of urban discharges on the coastal environment and groundwater quality case: Coastal area of ecological interest Stidia (West Mostaganem-Algeria)
The coastal area of Stidia, located in the extreme west of the wilaya of Mostaganem, has a significant agricultural and forestry potential and a renowned dune belt, which is of considerable interest for ecology, agriculture and seaside tourism. Unfortunately, this area suffers considerable consequences in terms of pollution, especially during the summer season, due to urban discharges without prior treatment, which cause contamination of groundwater and vegetable crops, thus harming public health and the coastal environment. Indeed, on agricultural land near the beach there is a wild lagoon where urban wastewater flows, which unfortunately are considered a source of irrigation for farmers. To assess water pollution in this sensitive area, physicochemical analyzes were carried out from January to December 2019, on wastewater samples at discharge and the lagoon and on groundwater (4 wells located near the lagoon). The results of the measured parameters obtained show concentrations exceeding international standards, which revealed chemical pollution of the groundwater. This is confirmed by the high levels of Chlorides 625 mg/l, which explains the values of Electrical Conductivity that reach 2460 μs/cm. Nitrate levels reaching 65.4 mg/l, proving nitric pollution. A high organic load is reflected in high values of BOD5 and COD values of up to 30 and 220 mg/O2/l respectively, confirming the strong degradation of groundwater and the coastal environment that compromises any sustainable development. Furthermore, the degree of contamination differs from one site to another depending on the distance from the source of the pollution and the depth of the water table.