Spike in giant Stingray deaths believed to be linked to heavy metal pollution

Monday, October 24, 2016 by: J. D. Heyes
Tags: heavy metals, stingrays, deaths

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(NaturalNews) Something is killing giant stingrays in Thailand, and local officials believe it could be lethal doses of heavy metals, the Bangkok Post is reporting.

Residents living in Samut Songkhram along the Mae Klong river are expressing their concerns to local authorities following the recent and mysterious mass deaths of the giant stingrays, which many have said is unprecedented in the western region's principle waterway.

Normally, the Post reported, residents along the river avoid catching stingrays because of their superstitious beliefs. Also, they note that the sea-faring animals are a barometer of the fragile ecosystem in the area.

But in recent weeks more than 15 of the giant stingrays, which are endangered and threatened already, have been found dead.

"I've never seen anything like this before," one local resident, Ubon Chanbandit, 60, a housewife and former fisherman in the Muang district, told the Post.

She added that while dead fish were discovered in the river last year because of wastewater, it was the first time she'd seen such mass death of giant stingrays.

Pollutants from a sugar factory?

Retired public relations worker Sompon Wangcharoen, 75, who was employed with the Tai Had Tambon Administration Organization (TAO), echoed Chanbandit's observations. He added that he, too, had not seen the number of stingray deaths recorded since September while working at TAO, a job he left 20 years ago.

He did say that one time, the river was polluted by wastewater from a sugar plant in 2010, and that resulted in the deaths of prawns (an English/Irish/Commonwealth name for swimming crustaceans and shrimp) and fish. However this time, he told the Post, the water did not smell as it did last time, which is the first indication the water was tainted.

Chatree Tharaseng, head of the fisheries office in Samut Songkhram's Muang district, said that everyone concerned is quickly working on efforts to figure out what is killing the giant stingrays. He told the Post that there was also a recent drop in plankton levels as a result of a large amount of rainwater, which also often leads to poor water quality in the river, due to run-off, most likely. However, it's not clear if that is the cause this time around when it comes to the death of the stingrays, he said.

Piya Promsthit, head of the Regional Environmental Office 8, said that officials discovered that a trio of water samples from three separate locations upstream from the Mae Klong Rover in Ratchaburi contained lower-than-normal levels of oxygen.

That said, a coordinated effort will be needed from several agencies in order to confirm what is causing the death of the stingrays. That will include lab examination and testing of the tissue of the dead sea creatures, as well as further analysis of the river water.

Authorities suspect a connection

But already the deaths of the stingrays has spurred some suspicions that perhaps factories upstream are discharging toxic, tainted waste into the river. As such, one environmental protection organization has already filed a formal complaint against a sugar factory in Ban Pong because the group suspects that it has discharged foul wastewater into the river.

"It must be investigated whether water discharged from these Ratchaburi-based factories is linked to the death of the stingrays," said Rattawut Wallathanaroj, secretary-general of the network for environmental protection and against corruption, the Post reported.

He added that provincial industrial authorities have taken water samples from the factories wastewater pipe for analysis.

He also said he believes there is a connection to the deaths of the stingrays given the location of the city of Samut Songkhram at the end of the river, which makes it a catch-all area.

Sources:

BangkokPost.com

NaturalScienceJournal.org

ThaiPBS.or.th