Arsenic contamination in groundwater in Zimapan, Hidalgo, Mexico

Arsenic contamination in groundwater has been detected in several studies in the region ofZimapan, Mexico. Arsenic contamination sources have been reported as natural and anthropogenic.In this study, the variation in concentrations of pollutants in mineralized zones,sedimentary rocks and anthropogenic activities was determined. Arsenic and lead concentrationsof 5.0?248.0 and 0.10?132.0 ?g L?1 were observed in groundwater, respectively.Water mineralization was medium to medium high. Conductivity values between 198.0 and970.0 ?S cm?1 were determined. Some contaminated wells showed conductivity values asmuch as 1,700 ?S cm?1. Open wells near mining waste showed conductivity values up to1,485.0 ?S cm?1. Groundwater showed neutral pH and alkalinity tendency. Arsenic concentrationswere low in the volcanic aquifer, and high in the aquifer with carbonate rocks. Theaverage total arsenic concentration was 47.8 ?g L?1. Arsenic concentrations of 20?100 ?g L?1were observed in 93% of the sampled points; concentrations greater than 50 ?g L?1 werefound in 20% of the total. Forty-seven percent of the evaluated points correspond tosamples associated with carbonate rocks