Arsenic exceeds safety limit in Kok, Sai riversOfficials from the Chiang Mai Natural Resources and Environment Office, together with Pollution Control Department authorities, collect water samples in the Kok River for lab analysis in late April last year. Water and sediment samples collected from Jan 13–16 in Chiang Mai and Chiang Rai followed reports of unusual turbidity and possible contamination. However, arsenic levels exceeding the standard of 0.01mg/l were detected at several locations. In the Kok River, arsenic levels of 0.011–0.012mg/l were found between Tha Ton Bridge in Mae Ai district and the Mae Nawao–Tha Ton Friendship Bridge. Tributaries including the Fang, Korn and Lao rivers, as well as the Ruak and Mekong rivers, met safety standards.

Source: Bangkok Post February 15, 2026 01:28 UTC