Physicochemical quality of groundwater and pollution risk in arid areas: the case of Algerian Sahara

Abstract

In urban areas, population growth generates significant amounts of wastewater which are treated in specialized treatment stations or rejected directly without control in the case of short water Bechar River. Because of their diverse backgrounds, these waters are often loaded with organic elements, minerals, and microorganisms; some of which could be harmful to health and is heavily involved in the degradation of groundwater that may be irreversible. The study was conducted on two boreholes located next to the Bechar River (north and south) by influencing wastewater localized on the course of the Bechar River. A work plan has been adopted; it is early to make a monthly monitoring of two wells during the period from January 2007 to April 2014, with a comprehensive analysis of physicochemical parameters, to determine the various anthropogenic contributions to polluting nature in the region and analyze their physicochemical composition, to explain the origin and evolution of each element. The analyses revealed the levels of Cl, NO₃, NO₂, NH₄, and phosphates that can be passed to the groundwater by the water surface runoff of the river; the wastewater undergoes a slow percolation through the layers Triassic. This is confirmed by the high levels of chlorides, ranging from 180 mg/l in 2007 to 216 mg/l in 2014 for drilling north and 199 to 336 mg/l for drilling south of the river, which explains the values of the conductivity of 990 μS/cm ranging up to 1050 μS/cm. Nitrate concentrations ranged from 11 mg/l to 28 mg/l for the drilling located north of the river.