Concentrations and Human Health Risk Assessment of Heavy Metals in Drinking Water Surrounding the Cerro de Pasco Mining District, central Peru

Heavy metals are natural in the environment and have existed in nature for the entire history of human development. However, anthropogenic activities such as industrial mining and smelting have elevated the concentrations of these contaminants in soil, air, and water to hazardous levels for ecosystems and humans. These metals are not biodegradable and can accumulate and magnify in organisms due to their bioaccumulative potential along the food chain, high toxicity, prevalence, and persistence in ecosystems. Metals can also enter into humans by digestion, respiratory, and skin pathways and cause non-carcinogenic and carcinogenic health impacts. Cerro de Pasco sits at 4,440 meters above sea level, marking it as one of the highest cities in the world, and one the most polluted. Inside the city's borders is a 350 meter deep open-pit silver mining complex that is swallowing the neighboring residential areas. We analyzed the concentrations of ten heavy metals in 73 water sampling locations surrounding Cerro de Pasco, and following the United States Environmental Protection Agency Risk Assessment Methodology calculated non-carcinogenic and carcinogenic health indexes to predict impacts on the surrounding human population. We determined that children are at a greater risk of adverse health effects than adults and the route of ingestion contributed more than dermal contact to non-carcinogenic and carcinogenic risk. Arsenic poses the greatest carcinogenic risk through oral pathways with 98% of sampling locations showing children at risk of carcinogenic effects over their lifetime.