The Nation
Thursday, Dec 10, 1998
Dr Sutee Titimuta, an official at the province's public health office, reported that the river's dissolved oxygen content had dropped alarmingly in some stretches during April, when many fish were found dead at the Ban Yoo weir near the city centre.
Sutee said untreated waste from the municipality and surrounding communities was the primary cause of the river's condition. The Lamphun public health office has therefore urged that a wastewater treatment plant be built for the city.
However, some local residents claim that pollution from the Northern Region Industrial Estate (NRIE) was largely responsible for the river's condition and the dead fish, which has now occurred two years in a row.
Piroon Chantham, chairman of the city's environmental volunteers committee, said that most of the city's sewage is released below the Ban Yoo weir, while the dead fish were found above it, where wastewater released by the NRIE several kilometres upstream would presumably collect.
The public health department's study also found that average lead levels in small fish had doubled from the year before: from 0.23 milligrammes per kilogramme (mg/kg) in 1997 to 0.46 mg/kg this year. The standard considered healthy for human consumption is 0.5 mg/kg.
Mean lead levels in big fish had also jumped from 0.01 mg/kg to 0.10 mg/kg, while the lead in medium-sized fish were measured at an average of 0.18 mg/kg.
Sutee said lead contamination was not yet a problem for the Mae Kuang River, but that it warranted further observation. ''We will do another study next year,'' he said, adding that the source of the lead remained unknown.
According to Piroon, however, residents of Lamphun had been warned not to eat fish from the river. The warning reportedly came from a local politician in a newspaper article, which claimed that the fish had lead levels over the health standard.
Valiya Nivatvongs, manager of the NRIE, said effluent from the industrial estate is monitored regularly and the amount of lead emitted from its wastewater treatment plant is under the standard set by environmental authorities.
She said there are other sources of pollution in the river upstream, including a food-processing factory and communities containing a total of about 1,100 families.
However, Charoen Manolee, a villager who lives along the river near the estate's effluent discharge pipe, maintained that it was the industrial estate which had made the river unusable.
''The estate releases its wastewater in the middle of the night and the smell is terrible,'' Charoen said. ''We used to be able to catch fish and shellfish in the river and sell them in the market. Now we can't even wash our clothes with the water.''
Valiya agreed that the smell from the estate's effluent discharge is a problem, but said that it was not a health hazard. NRIE is taking steps to improve its wastewater treatment system, she added.
Relations between the industrial estate and the local community have been strained since several workers at the NRIE died of mysterious causes. Critics, including northern non-governmental organisations, said the workers had died of lead poisoning, but the Industrial Estates Authority of Thailand, which runs the NRIE, said they died of Aids.
Lead is toxic to both humans and animals, but if it builds up gradually in an ecosystem it is not likely to cause sudden mass deaths of fish or animal life.
However, if ingested or inhaled in sufficient quantities, it can damage the nervous system and eventually cause death. Children contaminated by lead have been shown to suffer from reduced intelligence and increased aggression.
As a heavy metal, lead also tends to sink to the riverbeds when released into waterways, but so far there has been no study of the sediment at the bottom of the Mae Kuang River.
''That is not our responsibility,'' said Sutee. ''Actually, we
don't normally check fish either, since that is the
responsibility of the Fisheries Department. But in this case
we did because so many fish were found dead.''