Arsenic-contaminated drinking water and associated health risks in children from communities located in a geothermal site of Michoacán, México: Monte Carlo probabilistic method
Laura N. Rodríguez-Cantú, Marco Antonio Martínez-Cinco, José J. Balderas-Cortés, Iram Mondaca Fernández, María del Mar Navarro-Farfán, María Mercedes Meza‐Montenegro
Abstract
Arsenic occurs naturally in ground and spring waters in several geothermal regions in México as a result of natural geochemical processes. Therefore, the goal of this study is to assess the probabilistic health risk in children exposed to arsenic by drinking water from communities located in the geothermal site of Zinapécuaro, Michoacán, México. The water sampling was done monthly for one year and total inorganic arsenic was determined using Hydride Generation coupled with Atomic Absorption Spectrometry. The health risk was assessed using the Monte Carlo probabilistic method. The arsenic levels in water were found to be in the range of 10.4 to 58.9 μg/L, with the highest levels from the hot springs. For children, the 95th percentile of Hazard Index was (HI) >1 for all study sites, with the highest mean (HI = 11 ± 2.9) for Taimeo’s spring water. The ingestion pathway predominantly contributed > 95% to the total health risk in comparison to the dermal exposure route. These results show the potential non-cancerous effects of arsenic in drinking water for children are high. For children and adults, the 95th percentile of Total Cancer Risk (TCR) was 4.7 × 10−4 and 1.2 × 10−3 respectively, exceeding the US EPA safe threshold of 1 × 10−4, which is an unacceptable cancer risk. Sensitivity analysis indicated that arsenic concentration in drinking water, body weight and arsenic intake for children were the most relevant variables on the output parameter HI. Consequently, the environment and health authorities must make greater efforts to provide safe drinking water to protect the residents of Zinapécuaro County.