Mining activity in the central Andes poses a serious threat to human health due to the release of heavy metals in surface water. Long-term exposure to elevated levels of heavy metals, including lead, cadmium, copper, and arsenic, are known to have severe detrimental effects on human health. Mining exposes large quantities of metal bearing rock, which oxidize in the presence of oxygen and water, releasing heavy metal ions into surface water. Surface water contamination in Perú as a result of mining operations is of particular concern due to a lack of regulation of large-scale mines. In order to determine the impact of mining on surface water heavy metal concentrations, water samples were collected in nine streams throughout our three watersheds in the central Peruvian Andes. Results showed [Mn] and [As] exceeded the EPA maximum allowable limits at 55% and 14% of sites, respectively. The [Mn] was significantly higher in impacted streams than non-impacted streams. The [As] was elevated in some non-impacted streams and below the EPA maximum allowable drinking water levels in some mine-impacted streams. While Mn appeared to be impacted by mining effluent, As seemed to have a natural groundwater source. This study suggests Mn and As pose a serious threat to human health in the regions of study. The [Zn], [Cu], and [Pb] seldom exceeded the EPA maximum allowable drinking water limit (5%, 3% and 5% of sites, respectively). Dry season [Zn], [Cu], and [Pb] do not appear to pose a serious threat to human health in these regions. Further research is needed to understand seasonal variations in both dissolved and particulate trace metal concentrations. Implementing a community-based water quality monitoring program in study regions may also afford local residents more autonomy and local knowledge regarding the impact of mining on heavy metal concentrations in their surface water.
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