Assessment of groundwater pollution by heavy metals in the industrial zone of Skikda

Abstract

Pumped groundwater volumes have been estimated at 52 hm3 per year with 12hm3 per year being abstracted from oil installation industry in Skikda city, situated in the north east of Algeria. Large industrial demands of groundwater have caused prejudicial effect on alluvial aquifer through aquifer depletion and moreover by contamination of aquatic ecosystems. An environmental assessment was carried out on water resources collected from boreholes and river, the aim was to assess heavy metal contamination in water close to our industrial area. Indeed, 20 water samples were collected in December 2021, including surface water and groundwater. results reveal that Safsaf river presents an alkaline pH (7.49), a high conductivity which reached 10620 us/cm exceeding the WHO limit fixed at 2500 us/cm, dissolved oxygen reaching up to 5.21 mg/l, and a maximum BOD5 of 140 mg/l, this load exceeded WHO standards fixed at 25 mg/l. cadmium concentrations measured at 1.48mg/l as a maximum load which exceed WHO standards fixed at 0.05 mg/l, zinc concentrations show a large peak of 9.3 mg/l, when WHO standards limits it at 3 mg/l in water and arsenic was measured at 1.05 mg/l, greatly exceeding WHO standards fixed at 0.01mg/l. this high concentration of heavy metals may be of industrial origin, as the river flows through the industrial zone, or anthropic, as Safsaf passes through the entire city of Skikda. On the other hand, groundwater results indicate the presence of cadmium ranged from 0.005 to 5.09 mg/l and largely exceed WHO standards about only 0.003 mg/l. high concentration could be due to anthropogenic and industrial discharge. Also, presence of a high concentration of Zn ranged from 0.325 to 7.21 mg/l and largely exceed WHO standards about only 3 mg/l. and which has practically the same sources of pollution as surface water