Statistical Assessment of Water Quality in Mexico’s Contaminated Purisima Dam

Mexico's Purisima Reservoir is a significant aquatic ecosystem and a designated protected natural area. To comprehensively understand its environmental health, a recent study evaluated the reservoir's water quality and contamination through an integrated scientific approach. This involved analyzing water and sediment samples for metal/metalloid content and physicochemical properties. Data processing utilized WAWQI, PAST 4.03, JMP15.2, and QGIs 3.26.3. Primary elements found in the reservoir's water (0.002–0.1 mgL⁻¹) included
cadmium (Cd), chromium (Cr), mercury (Hg), lead (Pb), and arsenic (As). Strong associations (p<0.05) emerged between several element pairs: Pb and As; Cr with Hg and Pb; Hg with Pb and zinc (Zn); and Cd and Pb. Sediment analysis at 25 reference points concurrently showed arsenic (As) as the contaminant most enriched, largely due to anthropogenic mining and mineralization. Other elements generally mirrored natural crustal rock concentrations. We categorized the Purisima Reservoir's water quality as "poor," but biomonitoring revealed it to be "moderately polluted." This research offers vital insights into the environmental health of the reservoir, providing essential guidelines for preventive and corrective measures to manage and conserve this critical water resource.

Keywords: Heavy metals, Purisima Reservoir, Arsenic, water, sediment, WAWQI.