Unchecked pollution is wreaking havoc on Meghna’s aquatic life

The Meghna River in Chandpur, stretching 15 kilometres from Ekhlaspur to Chotaki in Matlab Uttar upazila, has turned into a graveyard for aquatic life.

In recent weeks, countless fish, snakes, frogs and other aquatic creatures have been found dead, floating on the water. Carried by the current, their lifeless bodies have been piling up along the riverbanks.

According to locals and media reports, the banks of the mighty Meghna River, in areas such as Ekhlaspur, Char Kalia, Babur Bazar, Dashani, Chotaki, Shatnol, and Mohanpur, are littered with an alarming number of dead fish.

Large numbers of dead fish, including species like chewa, seleng, med, shrimp, air, kachki, baila, and chapila, have been seen floating on the water and accumulating along the banks, carried by the current and waves. Other aquatic creatures have also been found among the dead.

"Much like the Buriganga River, where no fish except invasive species like sucker fish can survive, the Meghna is heading towards a similar fate. Eventually, even hilsa — Meghna's most iconic fish — could disappear."

Dr Mohammad Mahfujul Haque, professor, Department of Aquaculture, Bangladesh Agricultural University

The recent wave of dead fish and aquatic animals in the Meghna River may have persisted for the past two weeks, but it is far from a new phenomenon. This has been happening for years, with the situation worsening every time. The root cause of the issue is no secret either.

Md Abu Kawsar Didar, a scientific officer at the Riverine Station of the Bangladesh Fisheries Research Institute in Chandpur, has been investigating the crisis. After collecting samples from the affected areas, he revealed shocking levels of pollution in the river.

"The dissolved oxygen level has dropped to way under 5 mg/L, sometimes between 2 and 2.5, and the pH level of the water is now between 6 and 6.5, whereas it should ideally be between 7.5 and 9," he said. 

"Additionally, ammonium levels, highly toxic to aquatic life, have been recorded at 0.02 mg/L in some areas — double the critical threshold."

As per his assumption, the primary culprit is nothing but the untreated industrial waste. 

"This usually happens during the dry season, from January to March, before the rains," Didar explained. "Factories in the area release untreated effluents into the rivers, leading to severe toxicity that kills large numbers of fish and other aquatic animals.

"This isn't the first time either. We witnessed a similar scenario last year too," he added.

Despite this recurring issue, it is evident that no effective measures were taken previously, leading to yet another tragic episode for the river's ecosystem.

This year, however, the Department of Environment formed an eight-member committee on 31 January to investigate the matter. 

Nevertheless, there are ongoing concerns that the committee's findings may merely reiterate existing information without leading to any meaningful action.

So, experts stress the importance of addressing the root causes of the pollution and implementing effective measures to mitigate its impact.

Dr Mohammad Mahfujul Haque, a professor in the Department of Aquaculture at Bangladesh Agricultural University, described how the Meghna River's once-pristine banks have changed drastically over the past two decades.

"Between 2000 and 2020, industrialisation has urbanised nearly 70-80% of the riverbanks," he said. "Factories, oil refineries, textile and dyeing units, tanneries, fertiliser plants, and battery recycling units are all major contributors to the pollution."

He further explained the seasonal dynamics of this pollution. 

"During winter, when rainfall is absent and river flow decreases, pollutants concentrate in the water. Acidic substances, heavy metals, and other toxic compounds accumulate. The pH of the water drops, making it more acidic, while dissolved oxygen levels plummet, creating a lethal environment for aquatic life."

Dr Haque warned of a grim future if the situation remains unchecked. "Much like the Buriganga River, where no fish except invasive species like sucker fish can survive, the Meghna is heading towards a similar fate. Eventually, even hilsa—Meghna's most iconic fish—could disappear."

Meanwhile, Malik Fida A Khan, Executive Director of the Center for Environmental and Geographic Information Services (CEGIS), emphasised the urgent need to address industrial pollution at its source.

He acknowledged that no proper study has been conducted on this issue on their behalf yet but assured that a team will soon be sent to collect water samples from the Meghna River in Chandpur to carry out independent research, separate from government initiatives.

He further added, "As you know, this is not a new phenomenon; it has been occurring for years. We can safely assume that dissolved oxygen levels are critically low, and the water has become acidic, with a pH below 7."

And so, he stressed the role of untreated industrial effluents and airborne dust from cement factories, which form a thin layer on the water's surface and hinder oxygen absorption. 

"The Department of Environment [DoE] must identify the exact sources of such pollution — whether from cement factories or other industries — and take immediate action," he said. 

According to Khan, factories responsible for discharging untreated waste should be fined, and their operations should be suspended until they comply with safety standards.

"The DoE has the authority to take such actions. So, if they find sufficient evidence through proper studies, I see no reason why they wouldn't take bold steps before the situation goes out of hand," he explained.

On a different note, Dr Haque mentioned that while the Department of Fisheries focuses primarily on fish biology, broader issues like enforcing laws, maintaining river flow, and preventing pollution are beyond their jurisdiction.

"This creates a complex web of stakeholders, with the Ministry of Water Resources and the Ministry of Shipping being the primary authorities responsible for river management," he explained.

He stressed that protecting the entire ecosystem is now more critical than simply conserving fish populations. 

"Factors such as river flow, riverine environments, water quality, sedimentation, and dams play a significant role in the life cycle, migration, and breeding of fish in rivers," he said.

"The Department of Fisheries could provide valuable insights to ensure that the ecosystem is more suitable for fish. Therefore, this department should be given greater authority over river management to address these interconnected issues effectively," he concluded.