PCD ready to sting ethanol firm with fine
Bangkok Post 22 October 2016 | Apinya Wipatayotin
Wastewater thought to have killed rays
The Pollution Control Department (PCD) will lodge a complaint with local police next week against Rajburi Ethanol Co for allowing wastewater containing molasses to leak into the Mae Klong River, killing many giant stingrays.
PCD director-general Wijarn Simachaya disclosed the legal move yesterday at a press conference after his department completed its laboratory tests to confirm the type of chemical that might be the cause of death of the rarely found species, pointing out that a leakage of molasses from the plant into the river is strongly suspected.
Mr Wijarn said testing had shown that wastewater leaked from the plant into the river in Ratchaburi's Ban Pong district, polluting and killing aquatic life, including many native giant stingrays, in Ratchaburi and Samut Songkhram provinces from Oct 1 to 7.
He said that Rajburi Ethanol earlier admitted there was a leak from its last pond of treated wastewater at 8.50am on Sept 30. Many agencies subsequently tested the water in the river.
"The laboratory result has confirmed that ammonia was a key factor leading to the deaths of the stingrays. The department will file a complaint with local police next week against the company under the Environment Promotion Act BE 2535 as the company is accused of causing pollution," he said.
He also said relevant officials in Samut Songkhram province are assessing the financial damages to sue the company.
Tests found that dissolved oxygen in the lower part of the river amounted to 1.0-2.8 milligrammes per litre from Oct 4 to 10. This was below the level measured there in the same period last year.
Biochemical oxygen demand (BOD) in Samut Songkhram from Bang Khonthi district down to the estuary ranged between 11mg and 28mg per litre on Oct 7.
The wastewater that leaked from Rajburi Ethanol on Sept 30 continued to accumulate in the Mae Klong River at least until Sept 7.
It took six to eight hours for the water mass in the river to flow from Ban Pong district, Ratchaburi, to Bang Khonthi district, Samut Songkhram, and a high tide during the period blocked the water mass from reaching the sea.
Consequently, some of the wastewater settled in the riverbed and high levels of free ammonia killed aquatic animals, including the stingrays, which were unable to discharge ammonia from their bodies during the period of low dissolved oxygen, Mr Wijarn said.
Tests to simulate the condition of the river during the polluted period showed that the level of free ammonia soared 18 times and caused the sudden death of the aquatic animals, he said.
A total of 45 giant stingrays were found dead in the area in early October.
Nantarika Chansue, a veterinarian with Chulalongkorn University, said she found the chemical caused paralysis so the stingrays were unable to move to a safer place, adding she also found cyanide in the stingrays' bodies, citing increased toxification of their bodies, though she was