Natural Sediments, Gold Mining Contaminate Drinking Water

Protecting drinking water from contamination by bacteria and other parasites is the number one concern of government officials and or­ganizations dealing with water issues.

With an estimated 66 percent of Cam­bo­dians drinking unsanitary water, mostly from sur­face ponds and streams, the Ministry of Rural Development and international organizations have focused resources on drilling wells and training villagers to use them.

But in several provinces water wells have run up against a less deadly, but nonetheless dangerous, form of contamination: Arsenic.

According to a UN Children’s Fund study done in January 2004, most of Cambodia’s groundwater is free of toxic chemicals. But in 15.6 percent of wells tested nationwide by Unicef, arsenic concentrations were above the national standard of 0.05 milligrams per liter.

The national standard is also far less stringent than the guidelines recommended by the World Health Organization, which calls for arsenic lower than 0.01 milligrams per liter.

The presence of arsenic is highly concentrated in provinces bordering major rivers.

Along the Mekong River, Kandal has the highest rate, with 46 percent of wells containing arsenic-tainted water. Kompong Cham province is next with 35 percent. Roughly five percent of wells in Kratie, Kompong Chhnang and Banteay Meanchey provinces are contaminated.

Arsenic has no taste, smell or color. It can be detected only by chemical testing. The small quantities detected in Kandal province and elsewhere will not kill within a week—something dysentery from parasites does everyday in this country.

However, well water containing arsenic can cause the serious condition known as arsenicosis, according to Unicef’s report.

“Fortunately a study of Kandal province did not reveal any cases of arsenicosis yet, but the effects are long-term,” World Bank water and sanitation expert Jan-Willem Rosenboom said.

The first signs of arsenicosis is hardening of skin on the palms of the hands and soles of the feet into yellow or brown nodules.

Exposure over many years can lead to Black Foot Disease or peripheral vascular disease: In these cases patients gradually loose feeling in their extremities until gangrene sets in and amputation is called for. Arsenic exposure has also been linked to many types of cancer.

“The arsenic in Kandal province is a naturally occurring phenomenon,” Sieng Sotham, the director the Ministry of Industry, Mines and Energy’s geology department said Monday.

“When we first discovered these concentrations, we did not know about the natural de­po­sits and we thought it could be man-made. It is not possible that this arsenic comes from in­dus­trial pollution,” Rosenboom said.

In Kandal province and elsewhere, the gov­ern­ment paints pumps found to be arsenic-contaminated with red-colored paint.

But experts fear that villagers will overreact to arsenic findings and turn to drinking pond water, which would actually be more immediately dangerous for their health.

Because filtering arsenic from water is expensive, other options are being researched for affected wells.

“If you can’t have a well, rainwater collection tanks are an excellent option. Cambodians have long collected rainwater, but traditionally not in the large quantities needed to last the entire dry season,” Rosenboom said.

In some localities the concentrations of arsenic may be much greater due to the increased presence of gold mining, according to Sieng Sotham.

In 19 locations nationwide, small-scale gold mining has been found to be releasing cyanide and mercury—toxic chemicals used to separate gold from rock. Several localized incidents of cyanide poisonings have been reported.

“The cyanide and mercury…do not travel outside the mining area. Many of the mines…are in remote areas, but hill tribe people use the streams for everything,” Sieng Sotham said.

“In Kompong Cham we studied three villages. Over 800 people are affected there. Now they must travel 4 km for clean water. Some of the elderly only bathe twice a month,” he said.

The byproducts of gold mining, called tailings, often also contain arsenic.

No government study has been commissioned to examine cyanide, mercury or arsenic contamination from gold mining.


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