Recent research carried out by scientific research bodies in Venezuela shows that 92% of indigenous women of the Caura river, a major affluent of the Orinoco, have levels of mercury poisoning higher than internationally agreed permissible levels. Over one third of those tested have such high levels of mercury poisoning that they have a 5% risk of their newborn children having neurological disorders. The researchers note that the ongoing contamination of rivers, which results from the continuing illegal gold mining in the lands of the Ye'kuana and Sanema peoples, is getting worse and will lead to progressive bio-accumulation, posing an ever growing risk.