Transborder News: On April 4, 2025, Mr. Aweera Phakamat, Director of Environmental and Pollution Control office (EPCO) Region 1 in Chiang Mai, provided an interview regarding the water quality inspection of the Kok River. He stated that water samples had been collected and analyzed, revealing no cyanide presence. Cyanide naturally decomposes when exposed to sunlight and heat. However, arsenic was detected, a substance commonly found alongside gold ore.
EPCO collected water samples from Mae Ai District, Chiang Mai, at an initial site located just 500 meters from the Myanmar border (Thaton Subdistrict). The arsenic levels were found to be twice the acceptable standard, which is typically 0.01 milligrams per liter, but the test showed a concentration of 0.026 milligrams per liter.
Mr. Aweera further explained that additional tests conducted at two other locations—near the Thaton Bridge and further downstream—also showed arsenic contamination exceeding the standard at all three sites.
“If exposed to arsenic-contaminated water, such as in the past when people in southern Thailand suffered from ‘black fever,’ prolonged contact could lead to health issues, including cancer. Ingesting arsenic could cause food poisoning and other bodily dysfunctions,” said the Director.
When asked about how to address this situation for public awareness, Mr. Aweera stated that a meeting was held earlier that morning with relevant officials to issue warnings and communicate with community leaders. He advised that those swimming in the Kok River should minimize their time in the water, and individuals with open wounds should take extra precautions. Additionally, the use of river water for village water supply and agricultural purposes should be approached with caution.
“The water supply authorities must enhance their filtration processes because these contaminants can accumulate in aquatic animals. There must be thorough monitoring to determine whether arsenic has entered the food chain,” he added.
Regarding concerns in Chiang Rai City, where the Kok River serves as a primary water source for municipal water supply, Mr. Aweera stated that water samples were collected on March 24, and the results were expected within a day or two. However, since arsenic is a heavy element that can settle as sediment, the impact in Chiang Rai might be minimal. Still, he advised swimmers to avoid ingesting water and to seek medical attention if they experience irritation.
Ms. Somporn Phengkham, Director of the Community Health Impact Assessment Platform (CHIA) and an expert on transboundary pollution, noted that the presence of arsenic in the Kok River was not surprising given the history of gold mining upstream. She emphasized that further testing for mercury was essential, suggesting that predatory fish from the river should be analyzed for mercury accumulation. If detected, risk communication measures should be implemented to ensure public safety.
When asked how far mercury contamination could spread, Ms. Somporn stated that an ecological study of the Kok River should be conducted, including sediment sampling along the river up to Chiang Rai City to assess concentration levels at different points.
“As long as the source of pollution remains unaddressed, we must keep the public informed and take preventive measures,” she stressed.
Lieutenant Colonel Boonrot Kongkaew, Mayor of Thaton Subdistrict Administrative Organization in Mae Ai District, Chiang Mai, attributed the arsenic contamination to gold mining activities. He argued that arsenic would not naturally appear in the Kok River without external influence. He called for government intervention at the national level, as local authorities lack the influence to negotiate with those responsible. He also urged immediate action from the central government, stating that local demands often go unheeded, similar to the ongoing issue of cross-border forest fires.
“Previously, we only put up warning signs about deep water and dangerous zones in the river. Now, we must include contamination warnings. We are awaiting official guidance on how to proceed, as this is a sensitive issue with widespread implications. Currently, no one dares to enter the water. With these test results, the matter is settled—besides contamination, there is now an official warning about the toxicity. Initially, our members considered entering the water to set an example if the results were clear, but with these findings, even I, as the mayor, wouldn’t risk it,” he stated.
Meanwhile, local residents near gold mining sites in the Shan State of Myanmar, where the Kok River originates, have shared information and photos with reporters. The images depict small-scale gold mines authorized by the United Wa State Army (UWSA) for business operators. Large-scale land excavation and direct discharge of water into the Kok River have resulted in increased turbidity and arsenic contamination downstream as the river flows into Thailand.
See original Thai article, https://transbordernews.in.th/home/?p=41973
