Concentration, Distribution, and Potential Aquatic Risk Assessment of Metals in Water from Chott Merouane (Ramsar...

In this study, 28 surface water samples were collected from eight different sites throughout the Chott Merouane. Samples were detected by atomic absorption spectrometry for Cd, Co, Cr, Cu, Fe, Ni, Mn, Pb, and Zn. The dissolved metal concentrations (mg/L) ranged from 0.05 to 0.90 mg/L for Cd, 0.13-6.45 mg/L for Co, bDL-2.05 mg/L for Cr, 0.03-0.27 mg/L for Cu, 0.34-7.41 mg/L for Fe, 01.6-4.54 mg/L for Ni, 0.15-1.19 mg/L for Mn, 0.23-5.88 mg/L for Pb, and 0.01-0.28 mg/L for Zn. Compared with U.S. EPA standards and other freshwaters worldwide, the most mean concentration of metals in surface water of this salt lake are higher than the guideline levels of aquatic life. This was further corroborated by results from the water quality indices that Chott Merouane is seriously polluted by metals. The values of the metal pollution index indicated that metal pollution level was Cd > Pb > Ni > Fe > Cr > Cu > Mn > Zn, and those metals belong to moderate or high pollution level. The Nemerow pollution index further indicated that Chott Merouane was suffering from serious metal contamination. Based on geostatistics analyses, generally distributions of these metal contents decreased in the order of the North Chott Merouane ≈ the Northwest Chott Merouane > the Eastern part of Chott Merouane > the South Chott Merouane. The quality of water has drastically deteriorated due to the mixed source of anthropogenic inputs. Therefore, necessary conservation and management measures should be taken to improve the water quality of this Ramsar wetland.