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How safe is Meghna’s water?

  • Published at 01:25 am October 30th, 2018
Meghna  river
Photo: Syed Zakir Hossain/Dhaka Tribune

Experts say the river water will be undrinkable in five years

The cost of safe drinking water in Dhaka will triple if no action is taken against its current trend of pollution, a deputy director of the Department of Environment has warned.

The bulk of Dhaka’s water presently comes from groundwater provided by Dhaka Water Supply and Sewerage Authority (Dhaka Wasa).

As the water table is now depleting faster than it can replenished, however, Dhaka Wasa has turned to Meghna river as an alternative, which has already started becoming polluted. 

“If the (river) pollution continues, the water quality may further deteriorate, leading to a very high price for making it drinkable through treatment,” DoE deputy director Md Mustafizur Rahman Akhand said. 

According to a recent report released by the DoE, Dhaka Wasa and other stakeholders, if the current pollution trend continues, a toxic mix of pollutants is going to make the Meghna river water undrinkable in five years.

The joint report “Protecting Water Quality of the Meghna River for Dhaka’s Sustainable Water Supply” was released under the Dhaka Environmentally Sustainable Water Supply Project (DESWSP) on October 11.

The report’s other stakeholders were the Department for Forests and Climate Change, the Japan Fund for Poverty Reduction, and the Asian Development Bank (ADB).

It urged better governance and law enforcement to protect the river from uncontrolled industrialization, the dumping of waste, and the use of pesticides.

‘Drastic rise’ in pollution

Currently, Dhaka Wasa supplies 605 deep tube wells in Dhaka with groundwater.

Every year, the groundwater level declines by 2-3 metre, creating a shortage and causing 30-40 deep tube wells to become ineffective. 

Authorities have turned to Meghna River as an alternative. 

However, there are around 2,000 industrial factories situated along the banks of the Meghna in Narsingdi and Narayanganj, of which many are washing and dying factories which emit chemical waste into the river. 

Most of these factories do not have any Effluent Treatment Plant (ETP) and the ones that do hardly ever run them. Thirteen large factories are discharging wastewater directly into the river.

Under the Meghna project, the authority will pump water from two intake points 30 kilometres away from Dhaka via the Bisnondi and Haria canals.

This is despite Bisnondi canal being routinely polluted with waste from a number of small-and medium-sized textile factories, as well as by untreated domestic waste.

The other canals  located upstream - including Amider, Boatarder and Harihuda - are also being heavily polluted.

The report also says that the Meghna has a high presence of E-coli from the domestic waste of 3.3 million people who live in the area. 

The river also has high levels of the organophosphate insecticide Dimethoate, the herbicide Diuron, and the fungicide Carbendazim, and contains unacceptable levels of heavy metals such as chromium.

The level of Dissolved Oxygen (DO) - the element most essential for the survival of fish, invertebrates, bacteria and underwater plants - has also fallen to below acceptable levels over the past two decades, making the waters inhospitable to life. 

In 2002, the DO level of the Meghna was 7.5mg per litre, falling to 6mg by 2011 - both acceptable levels. From 2012 to 2016, however, the DO level fell to as low as 4.6mg. 

Since 2007, the level of Electrical Conductivity (EC) - a measurement of dissolved pollutants in the water - has increased from 124 to 164 microsiemens per centimetre. Prior to 2007, it was around 100.

The rise in the EC level directly affects the Chemical Oxygen Demand (COD). Although COD standard for drinking water is 4mg per litre, the rate in the Meghna was found to be as high as 38mg from May 2016 to Jan 2017.

What can be done?

A director of the environment department, who wished to remain anonymous, said selected areas will be declared as Ecological Critical Areas (ECA) to prohibit the setting up of environmentally dangerous industries in order to maintain water quality and to prevent pollution. 

“In addition, the government has planned a number of economic zones both upstream and downstream of the intake points,” he said.

The Department of Environment (DoE) is providing technical assistance for the Dhaka Wasa project. “If these areas can be declared as an ECA, industrialization can go in a planned and controlled way,” said Md Mustafizur Rahman Akhand, DoE deputy director.  

“Industries with state of the art technology to treat their waste properly will be eligible to get environmental clearance certificate in the ECA. Also, existing industries can also be monitored properly.”