Scientists urge for urgent action as more than one-fourth of water wells in the Red River Delta are contaminated with the carcinogenic chemicals
A resident in Vietnam's Red River Delta shows skin lesions caused by arsenic poisoning. Scientists have warned against an "alarming" contamination of arsenic and other toxic chemicals in the Delta's groundwater.
Rapid extraction has increased concentrations of toxic chemicals in groundwater throughout the Red River Delta in the past decade, according to a study published Tuesday (January 18) in the journal Proceedings of the National Academy of Sciences.
"This is the first time such an undesirable situation has been identified at such a large scale," lead author Michael Berg, a senior environmental scientist at the Swiss Federal Institute of Aquatic Science and Technology, wrote to Thanh Nien Weekly in an email.
Up to 65 percent of the ground wells in the northern region contain naturally occurring toxic elements, at levels which exceed the World Health Organization's (WHO) safety standards, according to the findings.
Chronic arsenic poisoning has been linked to cardiovascular diseases, skin lesions and numerous forms of cancer. These diseases may take years to manifest. And, while the symptoms of arsenic poisoning are treatable in the short-term, there is no way to reverse its long-term affects.
"About seven million people are at considerable risk of chronic arsenic poisoning. This is particularly worrying because groundwater is the main source of drinking water throughout the delta," Berg said.
Berg and colleagues analyzed samples from 512 private wells in the Red River Delta between May 2005 and January 2007. They found arsenic in 27 percent of the wells surveyed and manganese contamination in 44 percent of wells. Manganese is particularly harmful for newborns and children as it hampers the intellectual development.
"Our study reveals that arsenic enrichment in deep aquifers has been exacerbated by human activities, like extracting of large volumes of groundwater from deep aquifers that naturally contain little arsenic," said Berg.
In 1998 the arsenic problem in Vietnam was identified in the capital city of Hanoi and surrounding rural districts and has since been recognized in other locations of the densely-inhabited Red River Delta.
To identify safe and unsafe areas over the entire Red River Delta, a large-scale hydro-geochemical groundwater survey was launched in 2005. It included analysis of arsenic, manganese, selenium, boron, iron, salinity, phosphate, ammonium, sulfate, dissolved organic carbon, and 30 further chemical parameters.
Of the 16.6 million people that live in the Red River Delta, some eleven million people have no access to public water supply and therefore depend on other drinking water resources (such as private tube-wells).
"Concentration maps and arsenic risk modeling suggest that several million inhabitants of the Red River Delta are at risk of chronic arsenic and/or manganese poisoning," Berg said.
Having found an "alarming" contamination of toxic elements in the Delta's groundwater, Berg proposed urgent intensification of mitigation actions to reduce the risk of chronic arsenic poisoning.
"Several mitigation options are now available and should be implemented to avoid further exposure to arsenic-tainted drinking water. For example, point-of-use household sand filters were shown to be an efficient and socially accepted technology for the removal of arsenic from drinking water," he said.
Under the 2011 socio-economic development plan approved by the National Assembly - Vietnamese parliament - last November, 86 percent of people in rural area are expected to have access to clean water by the end of this year.
Only 40 percent of people in rural areas used clean water by 2009, according to the Ministry of Agriculture and Rural Development.
Berg hailed mitigation actions taken by the Vietnamese government but urged sustainable measures.
"Use of groundwater that contains elevated concentrations of arsenic and other geogenic contaminants... should, in the long term, be avoided by the utilization of other sources of drinking water," he said. "Alternatively, appropriate water treatment technologies must be evaluated and installed to produce sustainable drinking water that meets safe water quality standards for both rural and urban populations."
Berg said the consumption of groundwater containing arsenic has resulted in serious human health hazards around the globe but especially in the region's many delta countries, including Bangladesh, Cambodia, India, Myanmar, Nepal, Pakistan and Indonesia.