Farmers fix an underground water pump they use to water their shrimp farm in the Mekong Delta.

Groundwater levels have sunk 17 meters over a decade while much of the supply has been contaminated with arsenic.

Scientists have also found high levels of arsenic in groundwater and evidence that the substance may be present in people using the water, posing a risk of neurological disturbances and death.

Duong Van Vien, a lecturer from the Water Resources University, said the groundwater level in the Mekong Delta would drop to “dead” levels by 2014 if no action was taken to tackle the problem.

“Groundwater levels are between 12 and 14 meters lower than they were 10 years ago, with the highest decrease of up to 17 meters in some places” said Tran Van Thanh, deputy director of the Soc Trang Province Department of Natural Resources and Environment.

Authorities in Bac Lieu Province have also reported a decrease of 14 meters and said hundreds of wells dried up every dry season.

Pham Khoi Nguyen, Minister of Natural Resources and Environment, has also warned of a serious water supply shortage.

“We often think water is an abundant gift from God,” he said during the ongoing National Assembly session. “But the country could suffer a water shortage soon due to impacts from the climate change as well as an increase in demand.”

Unquenchable thirst

The Ho Chi Minh City People’s Committee has instructed the municipal Department of Natural Resources and Environment to all of the municipality’s 24 districts for illegal wells.

HCMC is extracting around 530 million liters of groundwater every day while only 200 million liters enter the supply daily, lowering groundwater levels by an average of one meter every year.

There are around 400,000 wells in the Mekong Delta and most of them belong to local families using them to meet household and irrigation needs.

Experts have warned that excessive amounts of groundwater are wasted when farmers use the supply for shrimp farming. This is common in coastal provinces like Ca Mau, Bac Lieu, Soc Trang, Kien Giang, Tra Vinh and Ben Tre.

Duong Van Ni, director of the Hoa An Biodiversity Application Research Center at Can Tho University, said it was wasteful for farmers to drill wells of up to 120 meters deep to extract fresh water only to mix it with seawater to produce saline water for shrimp farming.

Many families in Cau Ngang and Duyen Hai districts in Tra Vinh Province use up to three wells each for household use and shrimp farms and crop irrigation.

Bac Lieu Province farmer Nguyen Van Ut said he had begun pumping groundwater to his shrimp farm several years ago.

“The water becomes more salty in the dry season and that can stunt the growth of the shrimp. Many farmers cope with the problem by pumping groundwater into their farms,” he said, adding that some farmers had up to five wells for that purpose.

Acerbic analysis

Up to 6,500 wells in the provinces of Ca Mau, Bac Lieu and Tra Vinh have become unusable due to pollution or salinization, while experts have also warned of large scale arsenic contamination.

Ly Nhan, deputy director of the Ca Mau Province Department of Natural Resources and Environment, said the department had asked the provincial administra-tion to fill unused wells that allowed saline water from the surface to intrude on fresh groundwater.

Research by the Institute of Hygiene and Public Health at the Ministry of Health recently found “alarming” levels of arsenic contamination in groundwater.

Researchers found high arsenic contents in up to 40 percent of 2,966 groundwater samples in An Giang Province. The figure is 66.4 percent in Thanh Binh District in Dong Thap Province and 50 percent in several Long An Province districts.

Mai Thanh Truyet of the Vietnamese American Science and Technology Society (VAST) said symptoms of arsenic poisoning had recently surfaced in Mekong Delta residents who drink groundwater. The poisoning, also known as arsenicosis, has been linked elsewhere with the drinking of arsenic-tainted water over long periods of time.

He said the skin on some residents’ chests, legs and hands had darkened due to exposure to arsenic-laden water for five to ten years.

After 15 years of contamination, internal organs may swell and affect the neural and respiratory systems, he said, adding that cancer could appear in the liver, spleen, bladder and kidneys after 20 years.

He said researchers had found levels of arsenic contamination in the delta far above the safe level of 10 parts per billion stipulated by the World Health Organization.

Source: Thanh Nien, Agencies