Iron Contamination in Groundwater: Risk Assessment and Remediation Techniques in Egypt’s New Valley

Abstract

This study evaluates water quality (surface and deep wells as well as tap water) within villages of the El-Kharga Oasis (New Valley), focusing on their chemical composition, Fe contents, and potential hazards quantifying human exposure to Fe through different pathways, i.e., ingestion and dermal contact. Generally, the water quality meets the standards of the WHO guidelines for most sites, except for Fe, whose total and soluble contents in surface and ground waters exceed the permissible levels. Fe was higher in surface wells than in the deeper ones. Moreover, total Fe was higher than the permissible level in tap water, indicating potential health hazards for children living therein (hazardous index > 1). Another lab experiment was conducted to assess the efficacy of using dolomite, calcite, glauconite, and biochar for Fe removal from solutions artificially contaminated with Fe at a rate of 1000 mg Fe L−1. Generally, Fe solubility decreased with increasing the pH of media from two to seven. Dolomite exhibited the highest efficiency for removing Fe from the solution for five successive cycles, with slight reductions in efficiency from 100% to 93.67% between the first and fifth cycle. Overall, Fe removal efficiencies followed the order of calcite > dolomite > biochar > glauconite. This sorption fitted the Langmuir isotherm model, and its kinetics (5–20 min) followed a pseudo-second order model. Furthermore, Fe recovery from dolomite was high, ranging from 100%, while decreased slightly to 92.93% in the fifth cycle. Although the results for calcite were also promising, our results showed its higher erodibility rate compared to dolomite. These findings offer valuable insights towards managing water quality and developing solutions for treating contaminated water sources, with a specific emphasis on the efficacy of dolomite and calcite for removing Fe from Fe-contaminated water.