UPDATE
Chiang Mai and Chiang Rai Residents Warned After Toxic Contaminants Found in Kok River
Authorities have issued a public health warning for residents in Chiang Mai and Chiang Rai after high levels of lead and arsenic were detected in the Kok River, raising serious health concerns.
Aweera Pakamat, director of the Chiang Mai Environmental and Pollution Control Office, reported on Saturday that the Kok River—normally clear during the dry season—had turned unusually murky last month. Some locals also reported developing skin rashes after swimming in the water.
On March 19, environmental officers collected water samples from three points along the river. The results revealed turbidity levels nearly 10 times higher than the standard limit. More alarmingly, tests confirmed that lead and arsenic levels exceeded safety thresholds.
“Our analysis shows dangerously high levels of both lead and arsenic,” Aweera said. “Long-term exposure, especially to arsenic, significantly increases cancer risk.”
Residents are strongly advised not to use or consume water from the Kok River. If the water is to be diverted for use, it must be thoroughly tested in coordination with local water utilities.
Concerns are also mounting in neighboring Chiang Rai, where the Kok River has taken on a similarly cloudy appearance. Many locals suspect gold mining activities upstream in Myanmar may be contributing to the contamination.
Local authorities in Chiang Rai began water testing on March 24, with results expected soon, according to an official source.
Dr. Waranyu Chamnongprasatporn, chief of the Chiang Mai Provincial Public Health Office, warned that lead exposure can cause symptoms such as fatigue, headaches, and abdominal pain, while arsenic poisoning may result in rashes, nausea, and diarrhoea.
He emphasized that vulnerable groups, including children and pregnant women, should avoid all contact with the river. Residents should boil or filter any water before use as a precautionary measure.
Health officials will continue to monitor the situation and provide medical support where needed.
