Staff check water quality at the Ha Noi Water Company. The company denies claims that water supplied by several water companies in the city contained arsenic, a toxic chemical linked to skin cancer.


Nguyen Nhu Hai, General Director of the Ha Noi Water Company, said there was no evidence to substantiate the allegations.

"We examine the quality of water regularly and figures on the chemicals in the water are checked every day in all of these facilities. The level of arsenic is tested every six months," said Hai.

"Thus, it can be affirmed that water supplied by branches managed by Ha Noi Water Company meets the Ministry of Health's requirements. People do not have to be worried about using the water," he added.

Hai also said that water filters used improperly could filter out helpful minerals and affect the mineral compilation of the water. He made the statement after a study carried out last year by a group of Vietnamese scientists with researchers from Columbia University's Lamont-Doherty Earth Observatory, showed that arsenic had leached its way into a major drinking-water aquifer servicing Ha Noi. The most serious pollution was in the southern part of the city.

Underground water, which provides 35-50 percent of the total water volume provided to urban areas nationwide, has been reported by the study, "Retardation of arsenic transport through a Pleistocene aquifer", to be seriously polluted.

The experts, who took water samples from the households in 34 locations near 13 key water plants and four water stations, found that 46 percent of the samples had traces of arsenic exceeding levels permitted by the World Health Organization (WHO) and Vietnamese authorities.

Most of the locations with high concentrations of arsenic were located near water plants in Nam Du, Yen Phu, Luong Yen, Gia Lam, Phap Van and Linh Dam.

Arsenic in some areas was recorded as 10 to 50 times higher than safe levels, said Pham Hung Viet, a co-author of the study and a professor from the Ha Noi University of Science.

Scientists have also found a close correlation between the concentration of arsenic and the time of the year. The high arsenic concentrations occurred in the second and fourth quarter, while concentrations were lower in the first and third quarters.

Authorities in the capital have moved to filter arsenic from the city's water supply, but many people living in the suburban area remain off the water grid. Tran Hong Con, a professor from the Ha Noi University of Natural Sciences, adds that the city's water filtration techniques are out-dated.

"In developed countries, they don't use chlorine to filter water anymore, they use ozone or x-rays. But these methods are costly, and we haven't been able to afford that," Con said.

The study also found out that people living in areas affected by arsenic, many residents had showed symptoms of mental disorders, skin conditions and reproductive health disorders.