The Nation
Jan 12, 1996
Page A1 lead

Deadly toxins found off Eastern Seaboard

By JAMES FAHN
The Nation

Mercury and cyanide, two deadly toxic substances, have been found in the
sediment off Map Ta Phut industrial estate on the Eastern Seaboard.
        Authorities remain baffled as to the source of the alleged
contamination. And the conflicting nature of the new data has led to
calls from all quarters for further study.
        If the contamination turns out to be genuine, however, it could
represent a serious public health crisis for Thailand.
        Mercury is a neurotoxin which builds up in the food chain. When
ingested by people, it can lead to birth defects and chronic damage to
the central nervous system. In more severe cases it causes a loss of
hearing and vision, and ultimately death.
        Cyanide is an powerful poison which attacks the respiratory
system. A single dose of as little as 50 milligrams (mg) can lead to
immediate death.
        An environmental impact assessment (EIA) report being prepared
for the expansion of the Map Ta Phut industrial port has found, in some
instances, very high quantities of cyanide in the seabed of the Gulf of
Thailand.
        Initial sampling of the sediment in the port's basin found
cyanide levels as high as 4.46 milligrams per kilogram (mg/kg) of
sediment. Other high levels were found in the outer approach channel for
ships (3.45 mg/kg) and off the industrial estate's main drainage canal
(3.89 mg/kg).
        The consultant companies which are carrying out the study _
Siamtec International Ltd, Asian Environmental Protection Co Ltd and LG
Mouchel & Partners Ltd _ were so alarmed by the findings that they
carried out new tests, and this time found levels no higher than 0.02
mg/kg.
        The second set of samples, however, did yield higher levels of
mercury, in some cases more than ten times higher.
        The consultant companies stand by the validity of both sets of
results, and submitted a draft report to an evaluating committee earlier
this week.
        ``The testing methods were checked. There was no error,' said a
source from one of the companies, who asked not to be named. ``The
sediment samples were taken at different times of year, under different
tidal conditions. Both sets of results could be right.'
        Kasemsri Homchean, director of the environmental and safety
control division of the Industrial Estate Authority of Thailand, called
on the companies to check the results again.
        ``Why did the data change so much? Something must be wrong,'
said Kasemsri, who sits on the committee. ``They need to clarify why the
results are so different.'
        The source from the consultant company agreed that a broader
testing programme is needed.
        The presence of mercury in the waters of the Gulf of Thailand
has been known for some time, although authorities have yet to conclude
where it comes from.
        Natural gas from the Erawan field in the Gulf of Thailand is
known to be contaminated by mercury and other heavy metals. Cyanide
salts are also said to be present as dissolved trace elements in the
gas.
        The Petroleum Authority of Thailand's gas separation plant at
Map Ta Phut had to be shut down for more than a month in 1989 when it
was found that mercury had damaged the facility, causing a dispute
between the PTT and Unocal, the gas concessionaire. Pollution control
equipment has since been installed at both the PTT plant and Unocal's
drilling operations in the Gulf of Thailand.
        Representatives of both firms claim they have carefully
controlled the toxic wastes from their gas operations.
        Mercury and cyanide are also used in other industrial processes,
including downstream petrochemical plants in Map Ta Phut, and cyanide is
also used as a fumigant.
        The substances found in the Gulf of Thailand could therefore be
a result of waste water runoff or toxic waste dumping. It is also
possible their presence is a natural phenomenon.
        The IEAT's Kasemsri noted that the mercury levels found outside
Map Ta Phut's drainage canal (0.07 mg/l) were not as high as those found
offshore the port's western wall (0.28 mg/l), suggesting that waste
water from factories in the estate is not the main source for mercury.
        Whatever the source for the toxic substances, their presence
could hamper efforts to expand the industrial port, which will require
dredging the sea bottom and thus stirring up the toxic chemicals.
        During their initial testing of the sediment around Map Ta Phut,
the researchers found maximum mercury levels of 0.025 mg/kg. However,
mercury levels were significantly greater in the second set of samples,
reaching as high as 0.28 mg/kg.
        The IEAT's Kasemsri downplayed the significance of the mercury
findings.
        ``We are worried about the cyanide findings, but not the mercury
results. They are nothing new,' she said. ``Researchers at Chulalongkorn
University carry out a continuous water quality monitoring programme
around Map Ta Phut and they don't find mercury levels over the standard.
The levels are the same as those found naturally.'
        No environmental standards have been set for toxic substances in
marine sediment. There are, however, coastal water quality standards.
        An official at the Pollution Control Department (PCD), expressed
concern about mercury levels in the waters of the Gulf of Thailand.
Studies by the environmental agency have found that in several instances
the mercury levels exceeded the standard, although not consistently.
        According to the standards, cyanide levels should not exceed
0.01 milligrams per litre (mg/l) of water, and mercury should not exceed
0.0001 ml/g.
        The consultant firms did not check the water quality for these
substances.
        The highest mercury level recorded by the PCD in the waters off
Map Ta Phut was 0.00033 mg/l, more than three times the standard. That
figure was recorded in January of this year.
        The PCD is now carrying out further tests in waters all along
the eastern coast in order to determine the natural mercury levels in
the Gulf. It will also test for cyanide.