Groundwater Quality and Pollution Index for Heavy Metals in Saïs Plain, Morocco.

Background. Heavy metals contamination threatens groundwater resources in many areas around the world. Various methods to evaluate groundwater quality have been used to characterize sources of contamination and associated parameters. For assessment of heavy metals contamination, calculation of pollution indices is an effective tool for assessing water quality. Objectives. The purpose of the present study was to assess heavy metal concentrations and determine distributions in Sais plain, Morocco using multivariate analysis. Methods. A total of 144 groundwater samples were collected from twelve stations in Sais from January 2018 to January 2019, and were analyzed for heavy metals (arsenic, cadmium, total chromium, lead, copper, iron, manganese and zinc) using atomic absorption spectrophotometry. Results. Chromium was found to be a major contaminant affecting water quality in Station 2 (0.057 mg/l) and Station 8 (0.065 mg/l), while elevated levels of iron were found in Station 7 (1.4 mg/l) and Station 11 (0.45 mg/l), and elevated levels of copper (2.9 mg/l) and zinc (3.39 mg/l) were found in Station 11, relative to other heavy metals. The high concentrations of these elements are related to anthropogenic pollutants. The factor analysis showed two components controlling groundwater chemistry. The results of the present study demonstrate that the concentrations of toxic metals, like Fe and Cr, are present in slight excess in one or two stations during one season. The calculated heavy metal pollution level for the groundwater of Sais plain was below the index limit of 100. Conclusions. The results show that groundwater is not polluted with respect to heavy metals and is acceptable for drinking. However, precautionary measures, such as managing the use of agricultural inputs and avoiding the use of wastewater in agriculture, are recommended in this area.