Assessment of Potential Health Hazards of Trace Elements Contamination of Groundwater in a Shallow Aquifer: A Case Study in Guenniche (Northern Tunisia)

Abstract

Contamination of groundwater by trace elements causes unacceptable human health problems both in short- and long-term. In order to examine the concentration of nine trace elements (Mn, Fe, Cu, Zn, Hg, As, Cr, Cd, and Se), shallow groundwater samples were collected from twenty wells along Guenniche plain, which is one of the most important regions of farming at Bizerte governorate (Northern Tunisia). The analysis’ results show that the Mercury and Cadmium concentrations ranging between 0.04 and 1.91 µg L⁻¹ and 0.06 and 5.43 µg L⁻¹, respectively, exceed the national and/or international standards in some wells. All the Mercury samples’ results respect the international standard (WHO) set at 6 µg L⁻¹, and seven samples exceed the national standard (NT) set at 1 µg L⁻¹. For the Cadmium, two samples exceed the NT standard (5 µg L⁻¹), and five samples exceed the WHO standard (3 µg L⁻¹). The intense chemical pesticides used in agriculture and the uncontrolled disposal of domestic wastes are probably the cause behind the pollution in some wells. This region’s inhabitants are the most vulnerable population to carcinogenic risk because the results are higher than the acceptable risk level (between 10^–6 and 10^–4 set by the USEPA). The Arsenic, Chromium, and Cadmium risk level ranges from 2.5 × 10^–6 to 4.3 × 10^–4, 1.7 × 10^–8 to 1.10 × 10^–4, and 3.1 × 10^–5 to 2.7 × 10^–3, respectively. The findings in this research will inspire the decision makers to be more vigilant about the human health risk and to move forward with taking urgent and effective solutions to protect the Guenniche plain humans from trace elements contamination.