KUALA LUMPUR (March 15): An atmospheric science and climate change expert has urged the authorities to continuously monitor the air in not only Pasir Gudang but also other areas nearby to determine the concentration and movement of harmful gases.
Dr Mohd Shahrul Mohd Nadzir, a senior lecturer at Universiti Kebangsaan Malaysia's Faculty of Science and Technology, said it was not impossible for more gases to be emitted from the chemicals dumped into Sungai Kim Kim in Pasir Gudang, Johor.
Some 947 people, including students, had to seek medical treatment since March 7, after they reportedly inhaled methane fumes from the chemical spill and experienced symptoms such as shortness of breath, nausea and vomiting.
Meanwhile, 111 schools in Pasir Gudang have been closed temporarily to prevent more students from being affected.
Mohd Shahrul, who is also head of UKM's Research Centre for Tropical Climate Change System, told Bernama that eight of the chemicals identified by the Ministry of Energy, Science, Technology, Environment and Climate Change had probably generated the dominant gases detected in the affected area.
The eight chemicals, identified from water samples taken from Sungai Kim Kim, are methane, hydrogen chloride, acrylonitrile, acrolein, benzene, toulena, xylene and limonene, believed to have dumped into the river by a used tyre processing factory.
"The gases generated by the chemicals in the river are released into the air through the evaporation process. So far, eight chemicals have been identified but there could be other chemical compounds present there that need to be studied further," he explained.
He said when gas is released, it can interact with other gases in the atmosphere, while the sun's intense heat can cause these gases to disintegrate and form the molecules of other gases.
"This is why it is important for the authorities to monitor the air continuously to identify the toxicity level of the gases concerned," he added.
Mohd Shahrul said the current hot weather would make the situation more challenging as it would cause the chemicals to evaporate easily and react with other substances in the air, leading to higher concentrations of the substances created through these chemical reactions.
The wind direction, meanwhile, is also crucial as it dictates the movement of the gases to other areas, he said.
Explaining that the adverse effects of any pollutant is influenced by its atmospheric lifespan, he said: "A gas like methane that has a longer lifespan will not have any effect on human beings as long as its concentration in the air is below the level specified by NIOSH (National Institute of Occupational Safety and Health), that is 1,000 ppm (parts per million; exposure to methane over a period of eight hours)."
Methane, an invisible and odourless gas, can be easily removed from the atmosphere through its reaction with hydroxyl radicals. Acrylonitrile, on the other hand, may only have an atmospheric lifespan of 18 hours but it has carcinogenic effects, he cautioned, adding that high concentrations of this substance in the air can pose a danger to humans.
Adverse effects of acrylonitrile
Mohd Shahrul, who had carried out studies on the gases found on the earth's surface and ozone layer in Antarctica in 2016, said acrylonitrile was a yellow or pale-coloured liquid with an acrid odour.
Being a volatile organic chemical, it is highly flammable and can explode, he said.
"It is usually used to manufacture acrylic fibres. It is also used in chemical industries to produce other chemical substances," he said, adding that exposure to high concentrations of acrylonitrile can have adverse effects on one's health.
It can cause damage to the central nervous system, tiredness, memory problems, dizziness, muscle weakness, numbness and walking difficulties.
He said the International Research Agency for Cancer has revealed that acrylonitrile was carcinogenic, that is, it has the potential to cause cancer.
Effects of methane, benzene
Methane, a colourless and odourless flammable gas, is the main constituent of natural gas produced by wetlands, termites (as a result of digestive processes), biomass burning and livestock farming, among others.
Methane is also emitted during the combustion of petrol and fossil fuels such as coal, natural gas and oil.
"Methane is also a greenhouse gas that is causing climate changes. When inhaled, it can cause breathing difficulty, dizziness and vomiting. The heart rate can also go up and one can lose one's sense of coordination," said Mohd Shahrul.
Benzene, which is used in the production of chemical substances and rubber and plastic materials, will not cause serious harm if a person is exposed to it for short durations, he said.
However, if exposed to high concentrations of benzene over a prolonged period, it can harm the liver, kidneys, central nervous system and eyes.
Acrolein, meanwhile, can be toxic to humans when inhaled; it can cause upper respiratory tract irritation and shortness of breath.
Mohd Shahrul, who is closely following the crisis caused by the chemical dumping in Pasir Gudang, said people living in the affected areas should wear a proper mask, for example, the 3M 7502 Respirator 6001, that can filter the gases permeating in the air. He also advised them not to remain outdoors for too long.
He said the initial data retrieved by the Department of Environment's (DOE) air monitoring equipment proved to be very helpful in determining the concentration levels of the gases concerned.
He also said that additional air monitoring equipment should be installed in schools and public places to enable the authorities to have early access to vital information.
"In my opinion, the Pasir Gudang crisis has taught us all an important lesson. Safeguarding our environment is of paramount importance and it is not something that can be taken lightly.
"The science of environmental care is fundamental to all humans starting from childhood. Malaysia is a developing country, hence our mentality should also develop and not go backwards," he said.
He also said that the Pasir Gudang issue should not be politicised as it involved human lives.
"Everyone has a responsibility to help and ensure that such a thing does not recur in the future," he said, adding that DOE can collaborate with educational institutions armed the necessary expertise to carry out remedial measures to contain the crisis in Pasir Gudang.