Risk of pollution rises as our river levels drop, say experts
PETALING JAYA: A looming El Nino will not just cause water levels in Malaysian rivers to drop; it will also pollute them, experts warn.
Experts say this is because lower river levels reduce the natural ability of waterways to dilute waste, allowing pollutants to become more concentrated even if discharge levels remain unchanged.
Association of Water and Energy Research Malaysia president S. Piarapakaran said the base flow of Malaysian rivers has declined steadily over the years due to various factors.
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The El Nino and prolonged dry season, he said, can cause the base flow to become even lower, depending on the drought severity.
“During this period, the concentration of pollutants can increase and will only get worse if factors such as deforestation continue,” he said.
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“Lake systems are particularly at risk due to weaker natural recharge and dilution capacity,” he added.
Piarapakaran, who is also the Centre for Water and Energy Sustainability chief executive officer, proposed the establishment of a closed-loop chemical database to ensure hazardous waste is handled immediately, alongside having real-time monitoring features.
“This prevents unauthorised companies from handling waste materials, as the movement of chemicals – from importing and manufacturing to disposal – is monitored,” he said.
He also emphasised the importance of implementing regulations that would enable parties affected by water pollution to recuperate additional costs or losses in revenue.
Water Quality and Modelling specialist Dr Zaki Zainudin said smaller rivers are especially vulnerable, as they have less water to buffer changes.
“Even if the amount of pollution entering the river remains the same, lower water volume means pollutants become more concentrated.
“As a result, substances such as ammonia and, in some cases, heavy metals, may reach higher levels,” he said.
Zaki added that stagnant water bodies like lakes and ponds may experience increased algae growth during dry periods due to warmer temperatures and slower water movement.
Sahabat Alam Malaysia president Meenakshi Raman said climatic episodes expose rivers to higher levels of industrial effluents, domestic waste and agricultural run-off, increasing risks for communities dependent on the water source.
She proposed setting up special municipal council hotlines enabling nearby communities to alert authorities on polluted bodies of water.
“This is even more necessary during dry spells and in areas with various economic activities.
“Such hotlines also empower the public to be the eyes and ears of authorities,” Meenakshi said.
This comes as forecasts indicate that the El Nino phenomenon has a 62% chance of forming between June and August this year, according to the Malaysian Meteorological Department.
El Nino is associated with unusual weather events such as severe floods and prolonged droughts in parts of the world.
In South-East Asia and Australia, the weather conditions are drier than normal, while humid conditions are experienced in the central and eastern Pacific near the equator.
At press time, water levels at the Sungai Langat station in Selangor were recorded as “polluted”, according to the government’s River Water Quality Index (WQI) Management System.
It recorded a WQI reading of 59.
Another nine rivers were recorded as slightly polluted, as they had WQI readings ranging from 60 to 78.
These include Sungai Batang Sadong in Sarawak; Sungai Kulim in Penang; Sungai Selangor and Sungai Labu in Selangor; Sungai Linggi in Negri Sembilan; Terusan Mada and Sungai Mada in Kedah; Sungai Skudai in Johor; and Sungai Klang in Kuala Lumpur.
