Shallow wells dug for drinking water in the Amazon basin in order to avoid polluted rivers contain up to 70 times the recommended limit of arsenic, researchers warned Tuesday.
Samples taken from 250 sites along the Amazon—the first systematic analysis of the region’s well water—also revealed hazardous levels of manganese and aluminium, they reported at a conference in Vienna.
"In parts of the Amazon basin, groundwater contains these trace elements in concentrations that are potentially harmful to human health."
"Contamination should not be underestimated—all our data point in the same direction," she added.
Levels of manganese were up to 15 times higher than World Health Organization (WHO) limits, while aluminium exceeded WHO standards by up to three-fold.
Chronic exposure to arsenic is linked to cancers of the liver, kidney and bladder, as well as heart disease.
It is also thought to contribute to miscarriages, low birth weights and poor cognitive development in children.
"At this time, we cannot say how many people are affected," de Meyer said.
Because iron causes water to turn reddish-brown, people often let it stand so that particles—including some of the arsenic—can settle to the bottom.
De Meyer first uncovered dangerous levels of arsenic in groundwater drawn for drinking at a couple of sites in the Peruvian Amazon, leading her to suspect the problem was more widespread.