Dwindling water supply for human consumption and irrigation, and river pollution are the main threats facing Bolivia, Ecuador and Peru, according to a study  by British aid organization Oxfam International. The study indicates the three countries have “critical” levels of [water] stress which could lead to severe water scarcity if preventive actions are not taken.
[...] While [...] there is currently enough water to cover personal use, which is estimated at 120m3 per person per year, in Peru and Bolivia there are problems with supply for irrigation. The decreasing water supply is partly due to the loss of the surface vegetation layer in hydrological basins, caused by the expansion of agricultural activities, deforestation, overuse and burning.
Climate change is also playing a major role. Over the past 40 years, glaciers in the area have retreated more than 20% and the Amazon river level has also shrunk by 20%.
In rural areas in Bolivia, Ecuador and Peru, they have less than 40% potable water and sewerage coverage.
The decline of available water resources is made more serious by [river] pollution [...] caused by mining activities and oil companies. Heavy metals and chemicals are contaminating both river and underground resources, according to Jeroen Voes, one of the author’s of the study.
Another source of pollution is untreated sewage. In Bolivia and Peru, only 20% of sewage receives treatment, while in Ecuador the figure drops to 10%, according to the study.
More than half of the bigger rivers in these three countries are severely contaminated and some of them have stretches that are biologically dead, such as in the rivers Mantaro, Ene, Corrientes, Huaytará, Napo, Ramis, Rímac and Chira in Peru. The study also cited Bolivia’s Pilcomayo and Rocha rivers, and the Machángara, Guallabamba, Esmeraldas and Guayas rivers in Ecuador.
 El agua ante nuevos desafíos. Actores e iniciativas en Ecuador, Perú y Bolivia. View summary in Spanish here
Source: BNamericas [subscription site], 19 Mar 2009 ; Oxfam America [in Spanish] 20 Mar 2009