Preah Vihear provincial authorities collected fish and water samples for examination on Monday after nearly a week of mass fish deaths in the Stung Sen river.

Ea Sokha, the director of the Preah Vihear environment department, said the fish began dying on March 24. Local authorities appealed to people living along the river to refrain from consuming or selling fish from the river.

Sokha said that the fish and water samples have been sent to a Phnom Penh laboratory for examination. “There are 3 to 4 tonnes of dead fish per day,” said Sokha, adding that the deaths continue to occur.

Lut Sang, a member of local NGO Ponlok Khmer, said that his organisation visited the river last Friday after hearing complaints from villagers.

Sang said that he and many villagers believe that runoff from a factory owned by the Rui Feng sugar company – located 10 kilometres from the river, in Chey Sen district – is behind the fish deaths.

“We suspect that the company released pollution into the river,” he said.

Sokha, however, said “the villagers blame the company, but those are their suspicions”. Experts “have not officially confirmed the reason”, he said.

Tach Vuthy, a resident of Prame commune, said that some villagers still collected the dead fish to make prahok.

“They know that it will affect their health but they do not care. They care about having something to eat,” Vuthy said.

Kuy Yoeun, administration manager of the Rui Feng company, could not be reached for comment.