Mekong River Sand Sale Sparks Toxic Heavy Metal Fears in Chiang Rai

CHIANG RAI – Serious concerns have emerged in Thailand's northern province of Chiang Rai over potential toxic heavy metal contamination from the sale of sediment dredged from the Mekong River. The Marine Department’s Waterway Maintenance Office 7 announced the sale of over 322,789 cubic meters of sand and dirt, dredged from the Mekong River near the Chiang Saen Commercial Port No. 2. While interested buyers were allowed to inspect the site on July 1, residents quickly raised alarms about hidden toxic dangers within the river mud. This public panic stems from official water quality reports in the northern region. The Pollution Control Department has repeatedly tested the Mekong River area, revealing dangerous levels of heavy metals in the riverbed. Since May 2025, environmental tests have shown arsenic levels exceeding safe limits, with some sediment samples containing a shocking 94 milligrams per kilogram. Elevated levels of cadmium and chromium have also been found at several local checkpoints. These toxic metals can cause severe health problems if they spread into local communities. Buyers often use this dredged sand for local construction and land-filling projects, meaning the use of contaminated soil could directly threaten public health and local groundwater supplies. Following intense online criticism, the Chiang Rai Marine Office responded swiftly. They coordinated with Waterway Maintenance Office 7 to clarify the dredging project’s true goals. Officials explained the project is vital for safe boat navigation in the busy river, maintaining deep shipping channels for large cargo vessels and ensuring smooth water flow from the Kok River into the Mekong. This process helps prevent seasonal flooding and supports local trade around the Chiang Saen port. The Marine Office stressed that the sediment currently being sold is strictly old material dug up in past years, from routine dredging work completed in 2021, 2022, and 2024. They confirmed that no newly dredged material from 2026 is being sold, aiming to reassure the public that the currently available dirt is safe and was removed long before recent heavy metal spikes were recorded. To build public trust, the Chiang Rai Marine Office extended an open invitation to all relevant government agencies to thoroughly test the stockpiled materials. These independent laboratory tests will verify the absence of any dangerous heavy metals. Regional authorities hope this transparency will ease the fears of local buyers and residents, ensuring the safety of anyone using the soil for construction. The health and safety of the local community remain their top priority during this sale.