Post-Eid waste dumping triggers Halda River pollution 

The Halda River, the country's only natural breeding ground for carp, is facing a severe environmental crisis after large amounts of unsold raw hides and sacrificial animal waste were dumped into the river and its canals following Eid-ul-Adha.

Experts have reported a change in the river's water colour and confirmed fish deaths at several points along the river.

The Halda River Research Laboratory and environmental authorities have expressed serious concern over the potential long-term damage.

Dr Manzoorul Kibria, zoology professor at the University of Chittagong and coordinator of the Halda River Research Laboratory, said the pollution is the result of multiple factors—including post-Eid animal waste, monsoon flooding, and unauthorised industrial discharge.

"We have already received reports of significant fish mortality in different parts of the river. If immediate action is not taken, the situation could spiral out of control," he said.

According to Kibria, many residents and traders dumped animal remains directly into the river, particularly at night. A drop in rawhide prices this year also contributed, with unsold hides discarded without proper disposal.

"As these hides and innards decompose, they release ammonia and hydrogen sulphide, reducing dissolved oxygen levels and suffocating aquatic life," he explained.

This process, known as eutrophication, severely disrupts aquatic ecosystems.

The Halda River is home to endangered carp species and other biodiversity that may be at risk if pollution continues.

Kibria also warned that monsoon rains have worsened the problem. 

"Flooded riverbanks wash decomposing waste—especially from poultry farms and households—into the river as water levels recede," he said.

Dr Shafiqul Islam, another Halda researcher, highlighted illegal industrial waste dumping as a third source of pollution.

"Some factories take advantage of public holidays to release untreated waste into the river," he said.

In response, the Department of Environment (DoE) launched a drive yesterday to identify the sources of pollution and promised legal action against those responsible.

Ashraf Uddin, assistant director of the DoE in Chattogram, said, "We have collected water samples and are working to find those responsible. In some areas, the river water has turned dark red."

The Department of Fisheries is also attempting to remove decomposing hides.

Aminul Islam, senior fisheries officer of Hathazari upazila, said, "We deployed 30 river watchers in Hathazari and Raozan. We warned locals not to dump animal waste, but they did it anyway. Without public awareness, this cannot be controlled."

This is not the first incident of its kind. In 2020, a similar situation caused mass fish deaths and severe water contamination.

Environmentalists are now urging authorities to take urgent action to remove waste and monitor pollution levels.

They have also expressed hope that ongoing rainfall may help dilute the pollutants, but warned that without coordinated efforts, the Halda River may suffer lasting ecological damage.