Experts from the Institute of Standards of Cambodia (ISC) inspected Chinese-owned Rui Feng sugar company’s factory this week after suspicions that its runoff had caused last month’s mass fish deaths in Preah Vihear.

ISC director Chan Borin said yesterday that their team launched an investigation that lasted for two days as the factory was suspected by the local community of releasing waste into the Stung Sen River.

The factory, however, was found to have its own reservoir for waste storage, so the team went to the river for further investigation.

“We measured and tested the oxygen at the site and we figured that the water lacks oxygen, [so] the fish could not breathe and died . . . The level of oxygen is very low,” Borin said.

He added that the sugarcane waste would not have caused oxygen shortage as the “fish in the [waste] reservoir were alive”.

He suspected that plant decay had led to algal blooms, which deprive the river of oxygen.

According to Borin, however, the results of laboratory tests on the water samples will not be available for another 10 days.