J. Phys. IV France 107 (2003) 637
DOI: 10.1051/jp4:20030384

Effects of heavy metal pollution in the Pilcomayo river system, Bolivia, on resident human populations

K.A. Hudson-Edwards¹, J.R. Miller², D. Presto³, P.J. Lechler⁴, M.G. Macklin⁵, J.S. Miners¹ and J.N. Turner<sup>5

1</sup>  Research School of Earth Sciences at Birkbeck-UCL, University of London, London WC1E 7HX, U.K.
²  Department of Geoscience and Natural Resources Management, Western Carolina University, Cullowhee, NC 28723, U.S.A.
³  School of Geography, University of Leeds, Leeds LS2 9JT, U.K.
⁴  Nevada Bureau of Mines and Geology, University of Nevada, Reno, NV 89557, U.S.A.
⁵  Institute of Geography and Earth Sciences, University of Wales, Aberystwyth, Ceredigion, Wales SY23 3DB, U.K.

Abstract
The Pilcomayo river in Bolivia drains the Potosi mining district and flows downstream, exposing indigenous populations, who rely on the river for drinking water, irrigation and fish, to elevated levels of toxic metals. A preliminary analysis of agricultural soil and crops from four riverside Pilcomayo communities has shown that many agricultural fields are contaminated with heavy metals (Ag, Cd, Cu, Pb, Sb, Zn) and arsenic (As) However, concentrations of these elements in most crops are within guideline values. Concentrations of metals and As in samples of drinking water are, for the most part, lower than concentrations in Pilcomayo river water taken at the respective communities, and the drinking water concentrations are within guideline values. Exceptions are Sb and As concentrations in two of the communities. In irrigation waters, Zn and Pb exceed recommended guideline values in two of the communities, and may lead to high Zn and Pb values in some crops and soils. The work carried out to date suggests that the strategies used by these communities appear to considerably reduce their risks to exposure. Work is ongoing to develop more complex and effective strategies based on further geochemical analyses and social science surveys.

© EDP Sciences 2003