Several species of fish caught in the Kok River in Chiang Rai province have been found to be suffering from blotches on the skin and are infested with parasites and bacteria, although traces of heavy metals, such as arsenic, were not found, according to provincial fishery officials.
The officials had collected specimens, of both carnivorous and herbivore species, from various locations in the river for testing for the second time and sent them to Chiang Mai province for analysis.
An official said that most of the fish caught were found to have red blotches on their skin, mouths, tails and fins. Lab tests show parasitic infestations and bacterial infections.
He said he expects the latest results from Chiang Mai at the end of this month.
Many residents in Chiang Rai province are avoiding eating fish caught in the Kok and Sai rivers, over fears of arsenic contamination, allegedly caused by the unregulated discharge of waste water into the rivers from gold mining activities, operated by Chinese investors in Shan state of Myanmar.
The provincial administration advises people in the province not to consume water from the rivers, but they are unable to deal with the arsenic problem, because the Shan state is controlled by several armed minority groups, such as the United Wa State Army and Myanmar government troops,
