Microbiological, physicochemical, and heavy metals assessment of groundwater quality in the Triffa plain (eastern Morocco)

Abstract

The focus of this study is the physicochemical and bacteriological characteristics of groundwater in the Triffa plain, Morocco. In total, 34 groundwater samples were analyzed for major elements (Tp, pH, EC, K⁺, Na⁺, Ca²⁺, Mg²⁺, Cl⁻, SO₄ ²⁻, NO₃ ⁻, NO₂ ⁻, NH₄ ⁺, H₂PO₄ ⁻, CO₃, and HCO₃ ⁻) and trace metal (Al, Cd, Cu, Fe, and Zn) content. The results show that the pH values range between 6.7 and 8.9, electrical conductivity ranges between 740 and 7340 µS/cm, and nitrate content ranges between 1.7 and 212 mg/l. Hydrochemical facies represented using a Piper diagram indicate an Na–K–Cl type water. All the trace metal concentrations are within the admissible standard range except for Cd. The bacteriological analysis showed that the majority of groundwater samples are contaminated. Generally, the content of total coliforms, fecal coliforms, and fecal streptococci ranged from 0 to 140, 0 to 125, and 0 to 108 CFU/100 ml, respectively. The samples are grouped according to three factors. Factor 1 shows strong positive loadings of EC, Mg, Cl, Na and K with 51.91% of total variance (TV); factor 2 shows strong negative loadings of NO₃, SO₄ and Ca with 17.98% of TV; and factor 3 shows strong negative loading of HCO₃ with 15.56 of TV. We conclude that the quality of this groundwater is suitable for irrigation and domestic use (cleaning house, ect).