Electronic journal of the International Association
for Environmental Hydrology
On the World Wide Web at http://www.hydroweb.com
JEH Volume 9 (2001), Paper 6, March 2001
Posted March 9, 2001
GROUNDWATER CONTAMINATED WITH ARSENIC AND FLUORIDE IN THE ARGENTINE
PAMPEAN PLAIN
A. Cabrera
M. Blarasin
G. Villalba
Department of Geology, National University of Río Cuarto,
Argentina
ABSTRACT
The phreatic aquifer of the Los Jagüeles basin is made up principally
of Quaternary loessic sediments. It has sodium bicarbonate (high and middle
basin) and sodium sulfate (lower basin) water, with fluoride and arsenic
concentrations that exceed the permissible limits for human consumption.
The major contents of fluoride and arsenic are found in the middle basin,
where the predominance of loess, bicarbonate waters, and the highest Na+/Ca++
index
values coincide. The fluoride is derived from the main components of loess,
with anion exchange being the most important release mechanism. Arsenic
is derived from the alteration of volcanic glass and, although it is generally
related to reducing conditions, it occurs in the basin under oxidizing
conditions. In this paper, some appropriate techniques to lower the concentrations
of fluoride and arsenic are suggested.
Mónica Blarasin
Department of Geology
National University of Río Cuarto
Río Cuarto, Argentina
Email: mblarasin@exa.unrc.edu.ar