Heavy metals in Pattani River Basin

FACT SHEET - Environmental Health : Vol. 1 No. 1 October 1997
Heavy metals in Pattani River Basin
Dr. Pornpimol Varathorn Bureau of Environmental Health, Department of Health
Ministry of Public Health, Tel : 5904348
Pattani River
The Pattani River Basin
covers an area including
Yala and Pattani
provinces, with the
Pattani River as the main
tributary with a length of
210 kilometers. The river
flows from the southern
part of the ThailandMalaysia boundary,
passes Yala Province and
flows into the Gulf of
Thailand at Pattani Bay.
Landuse along the river
consists of forestry,
agricultural, community,
industrial and mining
activities. One known
principal source of lead in
the Pattani River is a
group of abandoned tin
mines in the watershed
areas of Yala s Bannang
Sata District. The falling
market value of tin over
the past decade caused
operators to abandon the
mines, but toxic metals
continue to wash off
dumped mine tailings
into tributary streams
during the rainy season.
Lead concentrations at PT03, Bannang Sata District were found to
exceed the standards during 1986-1992 and 1996-1997. This establishes
evidence that high lead concentrations in Pattani River at Bannang Sata
District still exist.
Other sources of lead are
industries along Pattani
Bay, especially shipyards
which use lead-based
plumboplumbic oxide in
ship building and repair
work.
Pattani River was found
to contain high lead
concentrations in 1986.
Follow up studies
investigated the high lead
concentrations in the
environment, such as in
water sediment and
marine flora, and the
resulting health effects in
children. The study by
Prince of Songkla
University in 1993,
showed high
concentrations of lead
over 3,333 mg in each
gram of sediment taken
from a tributary stream
running through a mine
dump in Ban Thamthalu,
Bannang Sata District. The
lead level decreased to
only 32 mg per gram in
sediment downstream,
but rose again at a
sampling station close to
the Pattani Bay.
Moreover, in 1994 it was
found that a species of
seaweed in Pattani Bay
used in the local diet,
Gracilaria fishery,
contained very high lead
levels.
The Department of
Health reported the
concentration of heavy
metals in Pattani River
collected from 4
monitoring stations during
1986-1997 as shown in
Heavy metal pollution of water has a number of man-made causes including
the processing of ores and metals, the industrial use of metal compounds
and, particularly, leaching from domestic and industrial waste dumps and
mine tailings. Main rivers in the eastern part of Thailand found high levels of
heavy metals contaminated from industrial waste. The heavy metal pollution
caused by mining occurred in Southern Thailand in Ron-Pibool, Nakorn Sri
Tammaraj Province, when arsenic leached from tin mine tailings caused the
skin manifestation of chronic arsenic poisoning. Toxicity of heavy metals is
particularly difficult to measure because effects causing damage to human
health may not show up for years through long-term exposure.
Lead Concentrations in Pattani River
The results showed that the monitoring stations at PT01 PT02 and PT04
found high lead concentrations exceeding permissible values of river and
drinking water quality standards of 0.05 mg/l during 1986-1992, but were
within the standards after that time. Lead concentrations at PT03, Bannang
Sata District were found to exceed the standards during 1986-1992 and
1996-1997. This establishes evidence that high lead concentrations in
Pattani River at Bannang Sata District still exist. (Figure 2)
Figure 1. The site of
monitoring stations are as
follows:
PT01 : Muang District,
Pattani Province
PT02 : Muang District,
Yala Province
PT03 : Bannang Sata
District, Yala Province
PT04 : Banglang Dam,
Yala Province
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Other Heavy Metals in Pattani River
Other heavy metals such as iron, manganese, copper, zinc, total chromium
and cadmium in Pattani River were found to be within the river quality
standard and drinking water quality standard in all of the monitoring stations.
The lead level of piped water in Muang District, Yala and Pattani Province, as
monitored from 1994-1997, did not exceed the permissible value of WHO
drinking water quality standard and was considered safe for consumption
purposes.
Health Effects
Recent studies have associated lead exposure with adverse health effects on
diverse systems, including the neurological, somatic growth, psychological,
hematological, metabolic and cardiovascular systems. New information
suggests that prenatal lead exposure may be related to minor congenital
defects, growth retardation, and neuro- behavioural abnormalities. Neuropsychological effects have been encountered at blood lead levels of around
10 mg/dl. The safety levels for blood lead were established by the Ministry
of Public Health at 25 mg/dl for children and 40 mg/dl for adults.
Children are the critical population group for exposure to lead. The data from
a 1995 study by Prince of Songkla University on blood lead levels carried out
in Ban Thamthalu and Ban Tengkadeng schools in Bannang Sata District (close
to a mine dump) and Ban Thachi school in Yaha District (locate further down
river), showed that the blood lead levels of preschool children (6-12 years)
were 16.5 and 12.9 mg/dl in Bannang Sata District, and 8.44 mg/dl in Yaha
District. The number of children with blood lead levels exceeding 10
mg/dl was found to be very high at 96% and 73% in Bannang Sata, but
was only 23 % in Yaha District. The results of a series of blood tests of
children in Yala Province supported studies reporting high concentrations of
lead in water, sediment and marine flora.
Proposed actions
Measures have been proposed by various governmental agencies in attempt
to control health effects and reduce the contamination. Procedures include
providing adequate and safe public water supply coverage in areas of high
lead contamination. The Provincial Health Office regularly monitors the
drinking water quality and river quality in risk areas contaminated by heavy
metals. The following actions are proposed:



Develop sensitive, accurate and simple indicators to detect the
adverse health effects of heavy metals at an early stage.
Increase awareness of the severity of heavy metal contamina-tion
and its harmful effects on children.
Increase the role of the people living along the river banks to assist
with the river rehabilitation.
REFERENCE
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4.
Bureau of Environmental Health. Heavy Metals in Pattani and Pak Pannang Rivers, 1997.
Regional Environmental Health Office 12. Heavy Metals Contamination in Pattani River (1995), 1997.
Prince of Songkha University. Lead and Heavy Metals Problem in Pattani Basin, 1996
WHO. Human Exposure to Lead: Report of the Human Exposure Assessment Location (HEAL)
Programme, Bangkok, 16-19 Nov. 1992.