Experts have warned the public not to consume snails collected from the Thanlwin (Salween) River after tests found arsenic levels 10 to 20 times higher than safety standards, raising concerns over acute toxicity.
Thai media reported that Somporn Pengkham, director of the CHIA Platform and lead researcher of a project on strengthening environmental health literacy through citizen science, announced the findings on May 3, 2026, with support from the Health Systems Research Institute (HSRI).
Somporn said laboratory tests at Chiang Mai University’s Environmental Science Research Centre found arsenic and lead contamination above standard limits in samples submitted by the Mae Sam Laep Subdistrict Administrative Organization in Sob Moei district.
Local authorities and community monitoring teams along the Thanlwin River have been informed and asked to communicate risks to residents. Villagers are advised to temporarily avoid consuming river snails, particularly vulnerable groups such as children, pregnant women, the elderly, and those with underlying health conditions including kidney disease and cancer.
“When food is scarce, local communities often have little choice but to rely on fish and other river life for survival. But continued consumption could have serious long-term health consequences for the community,” said Saw He Say, spokesperson for the Karen Rivers Watch (KRW).
Researchers plan to conduct further sampling to determine the presence of inorganic arsenic, the most toxic form of the substance, while collaborating with local monitoring teams to develop health risk screening tools suited to communities along the Thanlwin River.
The screening programme aims to identify individuals at high risk of exposure. Findings will be shared with local health services for further laboratory testing, including urine tests for arsenic and blood tests for lead. If contamination is detected, medical treatment and preventive measures will be introduced to help reduce long-term health risks.
Experts have urged the government to issue an official public warning, citing toxin levels in the snails that are far above established safety limits. However, for many locals, river snails remain both a seasonal food staple and an important source of income.
The findings have raised food safety concerns, as well as broader worries about the impact of transboundary pollution on communities along the Thai-Myanmar border that depend on the river.
Experts said the rising arsenic levels are a serious consequence of widespread mineral mining along the Thanlwin River, prompting riverside communities and environmental activists to demand an end to such activities.
