A provincial official on Thursday said tests have concluded that sudden fish deaths in Preah Vihear province’s Stung Sen River last month were caused by fertilizer runoff from a nearby sugarcane plantation, but the environment minister later said the investigation was ongoing and other culprits were still being considered.
Ea Sokha, the provincial environment department director, said that tests on river water conducted by the Environment Ministry on Monday had revealed high levels of fertilizer residue.
“We conclude that the fish deaths were because of fertilizer runoff,” Mr. Sokha said, adding that the ministry would investigate whether the company, Chinese-owned Rui Feng, used banned fertilizers on their crops.
Mr. Sokha said that several Chinese-owned sugarcane plantations operating in eastern Preah Vihear had illegally constructed a blockade across the O’Preal river, a tributary to the Stung Sen, to hold water to irrigate the sugarcane.
After two days of heavy rain in March, water overflowed the blockade, spilling onto the plantation and soaking up the fertilizer, which ultimately killed the fish, he said.
However, Mr. Sokha’s version of events was contradicted by Environment Minister Say Sam Al, who on Thursday denied that tests had uncovered any concrete proof of the sugarcane company’s culpability in the fish deaths.
“We’re not very clear at this stage. It is still under investigation,” Mr. Sam Al said. “It might be runoff from a nearby farm, but we’re not sure.”
Mr. Sam Al said the next most likely cause of the deaths was a poisonous plant species living along the river, which locals had told him bear fruits every six or seven years and poisons the water when the fruit falls from the branch. The identity of the plant was unknown.
“It is better to wait for a while. Give us one more week and we will look at every possible cause,” he said.
Villagers living along the waterway had previously accused Rui Feng of dumping chemicals into the river and killing the fish.
Rui Feng could not be reached on Thursday for comment.
