The investigation team led by Samut Sakhon governor and director of the Veterinary Medical Aquatic Animal Research Center (VMAARC) – Chulalongkorn University inspected the river and some fish cage farms along the river yesterday and tested the quality of the water.
After the inspection, the governor Mr Kamchatka Tansatien disclosed that it was likely that the mass death of fish in cage farming and the death of several stingrays in the river was from water pollution.
He said the water test showed that the biochemical oxygen demand or BOD quantity in the river is low and below standard.
There was also chemical substance in the water which might be the cause of pollution, he said.
Meanwhile officials from the VMAARC also collected samples of the dead stingray which was not discarded due to its big size for laboratory test.
The quality of water in the river passing the province is now in critical level and provincial authorities will soon assess the situation before giving instruction to cage fish farming in the river.
Since the beginning of this month a dozen of giant stingrays have died.
Cage fish farmers and residents suspected a factory near the river bank in adjacent Ratchaburi province is responsible.