The provinces of La Pampa (central Argentina) and San Juan (northern Argentina) were investigated due to known elevated levels of natural arsenic and a control province (Río Negro) was used as a known naturally low arsenic region.
The aim of the study was to ascertain the human health status of the local populations and decide whether a biotransformation pathway could be a useful remediation approach.
Most people within the two study areas rely solely on the natural water sources for their domestic supplies for cooking, washing, irrigation and watering cattle. At the same time, many of the rural farmsteads supply their own vegetables, grown in high arsenic-containing soil and irrigated with the elevated arsenic surface or ground water.
We used ICP-MS to determine total elemental arsenic and arsenic species (AsIII, AsV, MAV, DMAV and AB) in both environmental and biological samples. Water samples were collected from a range of sources (photo 1: surface, ground and domestic supplies) and compared with levels in the head hair and urine of individuals who drink these waters.
The majority of the water samples were shown (ICP-MS) to exceed the World Health Organisation (WHO) guideline level for total arsenic in potable waters by as much as 1000%. The composition of the environmental samples (HPLC-ICP-MS) mainly comprised inorganic arsenic species (AsIII, AsV) - the more toxic of the arsenic species under investigation.
Attempts have been made within La Pampa to reduce the levels of arsenic in the water by installing water treatment works (photo 2) in two towns (Eduardo Castex and Ingeniero Luiggi). However, this does not currently cater for the more remote populations. Recent publications have shown the prevalence of certain cancers within Argentina and the potential link with the high natural arsenic levels. The research has addressed the need for further work into the effects of consuming high arsenic-containing drinking water in Argentina and alternative methods for its remediation.
The work was carried out as part of a recently completed PhD studentship by Jenny O'Reilly at the University of Surrey in collaboration with the British Geological Survey. For publications on water chemistry and field As speciation techniques see the December 2010 issue of Environmental Geochemistry and Health http://www.springerlink.com/content/100162. Publication of the biomonitoring data is in preparation. Dr Jenny O'Reilly now works for LGC Ltd in Teddington, UK.
Photo 2: Water treatment works in La Pampa
