Research Reveals Lead Contamination in Diseased Catfish from Chiang Khan
Diseased catfish from the Mekong River in Chiang Khan, Loei Province show lead levels slightly above safety standards, though healthy fish remain safe to eat when properly cooked. Researchers from Naresuan University recommend avoiding visi
On May 12, 2025, a research team from Naresuan University, led by Associate Professor Dr. Thanapol Penyarrat, director of the digital database and systems unit at the Office of the Science, Research and Innovation Promotion Committee (TSRI), released research findings on bloated catfish caught from the Mekong River in Chiang Khan District, Loei Province. The team tested five types of heavy metals including arsenic, mercury, lead, cadmium, and manganese. The lead levels in the tested catfish slightly exceeded the standard of 0.3, with samples measuring 0.31 mg/kg.
Initial inspection results of catfish from Chiang Khan, Loei Province found elevated lead and mercury content in the flesh, with lead contamination most prevalent in diseased catfish. In contrast, samples from Nong Khai Province showed levels below safety standards and are safe for consumption. Diseased fish should not be eaten due to the high parasite burden in their intestines. While healthy catfish typically contain moderate levels of heavy metals, diseased fish show higher concentrations of arsenic, mercury, lead, cadmium, and manganese, though only lead approached standard limits.
Statistical analysis shows that diseased fish contain significantly higher heavy metal levels than healthy fish, consistent with international research indicating that diseased fish have compromised immune systems and are susceptible to infections and parasites. Blood tests conducted by Dr. Nathawut Charoenphol on diseased fish from Nong Khai Province confirmed exposure to heavy metals, DNA damage, red blood cell abnormalities, numerous parasitic infections, elevated white blood cells, and bacterial infections.
Catfish from both Chiang Khan and Nong Khai require continued monitoring. However, the public should not panic as only visibly diseased fish are affected, while healthy-appearing fish remain safe for consumption when properly cooked. The research team will collect additional water, sediment, and fish samples weekly for further testing to determine heavy metal contamination levels and will coordinate with provincial authorities on management strategies.
