People living along the Kok River in Thailand’s Chiang Mai and Chiang Rai provinces have been advised not to use water from the river for consumption due to the excessive amounts of arsenic it contains.
The poison is believed to originate from extensive gold mining in Mong Hsai town in Myanmar’s Shan state.
Arveera Pakamat, director of the Environment and Pollution Control Office in Chiang Mai, said officials took water samples on March 19 from the Kok River in Mae Ai district for testing which revealed that the arsenic content was twice the safe level.
The standard level of arsenic in natural watercourses is 0.01mg/L, but the samples from the Kok River were found to contain 0.026mg/L, which is harmful to health, according to Arveera. He added that the water in the river is currently about nine times cloudier than normal.
Other heavy metals such as cadmium and lead were also found in the water samples, he added.
Arveera warned that drinking water contaminated with arsenic can cause stomach upsets and, if the water is consumed regularly, accumulation of arsenic in the body can be carcinogenic. Exposure to arsenic also causes skin rashes.
Results of tests of water samples taken from the river in Muang district of Chiang Rai province are expected in the next two days.
According to a human rights organization in Myanmar, there were no gold mining activities in Shan State until 2020, when Chinese companies arrived to search for gold.
Currently, four Chinese companies are engaged in open-pit gold mining close to the Kok River in Mong Hsai. More than 300 Chinese nationals work in the gold mines around the clock.
Water used in the gold extraction process is drawn from the Kok River and is directly discharged back into the river without any post-use treatment, the organization claimed.
