Hanoi (AsiaNews / Agencies) - Arsenic, manganese, selenium, barium and other toxic substances were discovered in drinking water wells of the Red River Delta, which also supplies Hanoi.
A study published last week in the journal Proceedings of the National Academy of Sciences, shows that 65% of the wells are polluted. To the point that the newspaper has suggested the government should find other water sources or improve anti-pollution facilities.
The study considers that the continuous pumping of water from deep aquifers, for over a century, has caused naturally occurring arsenic in groundwater above to seep downward. From 2005 to 2007 512 private wells were reviewed and have shown that arsenic poisoning in about 27% of the wells, a million people use drinking water with concentrations of 5 times the limit set by the World Health Organization.
The researcher Michael Berg, head of research conducted by Swiss Federal Institute of Aquatic Science and Technology, explains that the situation is difficult because "the manganese is present where there is no arsenic, and vice versa. This makes it difficult to know which wells are really clean".
The area of the Red River Delta is one of the world's most populous, with about 1,160 persons per square kilometre. 16.6 million live in the area and about 11 million people have no access to public drinking water, but depend on other sources such as private wells. At least 7 million people are at risk of arsenic poisoning. Manganese pollutes about 44% of the wells, affecting the drinking water of 5 million people.
Arsenic can cause vomiting, sudden abdominal illnesses, dysentery with blood and is connected with various cancers of the skin, kidneys, lungs. Water with more than 10 micrograms of arsenic per liter is considered unhealthy, but the substance is widespread in the waters of many countries, including China, India, Thailand and Bangladesh, but even in the U.S.. For years, experts fear that the deep aquifer in many countries of Southeast Asia contain high amounts of arsenic.