Hazardous Heavy-Metal Levels Detected in Northern Thai Rivers

Picture courtesy of Bangkok Post

Authorities in Thailand have detected unsafe levels of heavy metals, notably arsenic and lead, in the Kok, Mekong, and Sai rivers in Chiang Mai and Chiang Rai provinces. The pollution is suspected to originate from outside Thailand, posing potential health risks to local communities.

Health deputy permanent secretary, Dr Weerawut Imsamran, announced on Wednesday that environmental officials assessed the river water quality on May 1 and 2, identifying elevated heavy-metal concentrations at multiple sites in these northern provinces. Such contamination could have serious health implications, particularly affecting children, pregnant women, and the elderly with symptoms like nerve disorders and irregular heartbeats.

In response, teams from the Department of Disease Control and the Department of Health will investigate the presence of arsenic in the local food chains over a four-month period. Dr Weerawut recommends consumers thoroughly wash vegetables and fruits to reduce arsenic exposure.

Aweera Pamat, director of the Environmental and Pollution Control Office 1, noted that from April 21-24, staff collected surface water at 12 locations along the Kok River, which originates in Myanmar. Nine sites showed unsafe arsenic levels, spanning three locations in Chiang Mai's Mae Ai district and six in Chiang Rai's Muang district.

Investigations into domestic pollution sources, including factories, mines, and farms along the Kok River, revealed no significant heavy-metal discharges within Thailand. This shifts the focus to potential cross-border contamination sources.

Despite the findings, tap water in Chiang Mai and Chiang Rai has been deemed safe for consumption. Heavy-metal pollution is commonly associated with byproducts from mining activities, highlighting the importance of regional cooperation in addressing this environmental challenge. The government continues to monitor the situation closely to safeguard public health and environmental quality.

  Adapted by ASEAN Now from Bangkok Post 2025-05-22