HEALTH RISK ASSESSMENT AND THE IMPLICATIONS OF LOW-LEVEL EXPOSURE OF ARSENIC IN DRINKING WATER OF THE YAQUI VALLEY, SONORA, MEXICO

Drinking water has been considered as the predominant pathway of human exposure to environmental metals in agricultural areas at arid regions. The hydrologic Yaqui basin hosts some of the principal copper-dominated deposits that can be considered part of a larger belt of intrusion-related ore deposits of northern Mexico and southwestern United States. The water crosses over these rocks and finally deposits the water in the Yaqui valley aquifer.

In this work, As-content of drinking water was analyzed from three indigenous towns located at the Yaqui agricultural valley. Total arsenic was determined by atomic emission spectrometry with inductively coupled plasma (ICP-AES). Water contains low levels of As when compared to areas such as Bangladesh, Argentina, and Comarca Lagunera in Mexico. However, previous research shows negative health effects for low dose and chronic exposure to As. Furthermore, we used a murine model to evaluate the health effects in living organisms. Mice were exposed to drinking water with low, medium and “high” As contents (0.006, 0.012 and 0.075 mg/L, respectively).

The mice presented behavioral changes and aggressiveness. Those alterations coming from the interaction of animals and a neurotoxic agent, that could be extrapolated to human beings. Moreover, the results from this work show that the Yaqui valley is part of a geological arsenic province that deserves further research, mainly because nearly 50% of Sonoran population live in cities and towns located within this province.