Hydrogeochemical characterization of the presence of arsenic in the Puelche aquifer in the area of Mataderos, Buenos Aires province, Argentina

摘要

The Chaco-Pampean plain, located in central Argentina, presents arsenic in groundwater related to volcanic glass from loessical sediments. As this region occupies an area of 1 million km2, approximately, water quality controls are essential. This research gives insight into origin and dynamics of arsenic from the Puelche aquifer in Mataderos, Buenos Aires province, an industrial urban zone. Eighteen wells were monitored and chemically characterized, and arsenic levels, origin and hydrogeological aspects were evaluated. Arsenic concentrations ranged 0.01-0.025 mg L~(-1). Forty per cent of the samples exceeded the limit set by the Argentine Food Code, 0.01 mg L~(-1), being this data remarkable because several food industries are settled in the study area. Spatial analysis demonstrated that the south zone presents higher concentration than others. This difference may be related to the natural origin, coming from Pampeano aquifer filtration, where geological, structural and chemical characteristics favor the presence of As.