Arsenic levels exceed safe limits at Sai River test sites - Bangkok Post

(Photo: Pollution Control Department) Arsenic levels in the Sai River exceeded safety standards at all monitoring points in the latest survey, prompting Thai authorities to step up water quality checks and seek cooperation with Myanmar and Laos.

The Pollution Control Department (PCD) on Sunday released findings from its 23rd round of water quality testing, conducted in late September at 23 stations along the Kok, Ruak, Mekong and Sai rivers in Chiang Mai and Chiang Rai.

Arsenic levels in the other three rivers remained within safety standards, although the department reported rising concentrations in the Mekong, which it linked to flooding from neighbouring countries.

The PCD has instructed provincial authorities and relevant agencies, particularly the Provincial Waterworks Authority, to intensify checks on raw water and tap water.

Investigations are also under way into possible arsenic contamination in agricultural products, including rice, although more data is needed.

The department said inspections had found no domestic pollution source responsible for the contamination in northern Thailand, prompting efforts to investigate the problem with neighbouring countries.

A joint Thailand-Myanmar working group will meet later this month. The PCD will also coordinate with Laos through the Mekong River Commission to monitor water quality in border areas this month.

The department is working with the United Nations Industrial Development Organisation, Japan, SCG and the Massachusetts Institute of Technology in the United States to study contaminated sediment management and improve heavy-metal detection equipment.

That said, the PCD said excessive arsenic levels in surface water did not necessarily mean tap water exceeded safety limits.