Scientists have discovered that coral reefs at Ao Phrao beach on Koh Samet in Rayong's Klaeng district still show signs of damage, six months after the area was flooded by tonnes of crude oil.
Boats remove oil-drenched waste from Ao Phrao beach on Koh Samet. The beach has almost returned to normal after a week of clean-up operations following the crude oil leak from a PTT Global Chemical pipeline in August 2013. (Photo by Thiti Wannamonth)
Marine scientists from Kasetsart University's Faculty of Fisheries, led by the head of the Department of Marine Science Thon Thamrongnawasawat, released their findings yesterday.
Mr Thon said no further damage has been detected, but there are no signs of a full recovery taking place yet.
The survey did locate, however, several indicators of recovery. These include a decreasing amount of petroleum hydrocarbon in sea water and an increasing number of small marine life, especially small crabs. Their numbers were found to have increased to 40 per every square metre, compared with zero just after the oil spill.
Mr Thon's team of scientists has been conducting a marine ecological impact system survey on Ao Phrao beach and in nearby areas since the crude oil leak from a PTT Global Chemical pipeline on July 27.
"The good news is that there is still no further escalation in the phenomenon of coral reef bleaching,'' he said.
''The coral reefs themselves are recovering from their illness. But we have not yet seen any baby coral attached to the side of old ones. If we see it, we are confident that a full recovery will take place."
Mr Thon said that baby coral is usually found between May and June. If signs of baby coral appear, it will increase the coral population in the colony. About 60% of the coral reef, most of which is mountain coral, became bleached after the oil spill. After two months the bleaching showed signs of tailing off.
Around 50 rai of coral reefs along Ao Phrao beach — the biggest area of coral reef on Koh Samet — suffered from bleaching.
Mr Thon hoped that five years would bring about a full recovery, if there are no more incidents that pose threats to the coral.
Shettapong Meksumpun, a lecturer at the Department of Marine Sciences, who joined the research team, said the quality of sea water is still good enough for swimming, as the amount of petroleum hydrocarbon present is less than one microgramme per gramme.
The safety level of sea water for recreation should not exceed one microgramme per gramme.
Meanwhile, a number of petroleum hydrocarbon in sediment at Ao Phrao beach is still high, compared with other beaches. The latest measurement found a level of petroleum hydrocarbon at two microgramme per gramme, compared with only 0.2-0.3 microgramme per gramme at other beaches.
He said that a remaining high amount of the crude oil's component could impact small marine life over a long period of time, which is why close monitoring is needed. Seafood from the area is safe to eat now, he confirmed.
Fishermen in tambon Pak Nam of Rayong’s Muang district yesterday found tarmac-like material near Laem Charoen and PMY beaches.
The strong-smelling, black, sticky material could be seen drifting along a five-kilometre stretch of the shoreline, raising fresh worries of a remaining oil slick from the incident.
Fishermen fear the material may affect the environment and yesterday tried to dispose of the material by setting fire to it, said Thammanun Thisabadi, a local fisherman.
The material was found comprise a mixture of mercury and arsenic, both of which which are extremely harmful to marine species, according to the examination conducted by a lecturer at Silpakorn University’s Faculty of Sciences.
Experts believe the toxic material could be lube oil secretly discharged by a large ship.