Water of rivers surrounding capital Dhaka is now murky and spreading offensive smells all the time as untreated industrial effluent, urban wastewater, agro-chemicals, sewage water, storm runoff and solid waste are being dumped in the rivers.
Five rivers surrounding the capital including the Buriganga, Shitalakshya, Turag, Dhaleshwari and Balu, once called the lifeline of Dhaka, are being polluted from more than 300 drains on the banks.
At least 3.5 lakh kilograms of liquid waste and solid garbage are being mixed with river water every day through these drains.
Although the government had identified at least 185 sources, private statistics found more than 300 sources.
To close these sources, a task force committee was formed in 2009 keeping the then shipping minister as chairman of the committee.
Although the task force committee is still active, no decision has been taken to close the source in 12 years.
Experts suggested government agencies must work together to prevent river pollution.
According to a recent report of Bangladesh Inland Water Transport Authority (BIWTA), about 3.5 lakh kg or 350 tonnes of toxic waste falls into the river water every day from about 7,000 industries and other residential areas.
Of those, 60 percent is industrial waste, 30 percent waste is produced from City Corporation, WASA and Union Parishad drains and the remaining 10 percent is household and other waste.
The amount of dissolved oxygen in the Buriganga water has reached almost zero level. Healthy surface water should have dissolved oxygen concentrations above 6.5-8mg per liter, according to international standard. As a result, fishes and other aquatic species are at the high risk of extinction in the Buriganga due to the toxic water.
According to a report of World Bank, Buriganga is currently one of the 10 most polluted rivers in the world.
The water of the Buriganga contains heavy metals like chromium, iron and zinc. The condition of other four rivers is almost similar.
Abu Naser Khan, Chairman of Save the Environment Movement widely known as POBA told the Bangladesh Post, “The government enacted a law in 1995 making it compulsory for all industrial units to use effluent treatment plants in order to save river waters from pollution. But most of the industry owners hardly follow the rule.
“On the other hand, although many of them have this plant, they do not use it as it is expensive,” he said, adding, “As a result, all the untreated waste are being gone to the river waters.”
According to the BIWTA report, the Buriganga, Shitalakshya, Balu, Turag and Dhaleshwari rivers around Dhaka are being severely polluted every day.
The river water has lost its normalcy due to pollution. According to the Environment Protection Act-2007, fish and aquatic animals need at least 5mg dissolved oxygen per liter of water.
At present, the amount of dissolved oxygen in Sadarghat area of Buriganga is only 0.24 milligram, 0.69mg in Faridabad area of Dholaikhal, 0.98mg near Shampur canal, 0.63mg in Pagla area, and 0.29 near Mitford Hospital in the river Buriganga.
The highest amount of oxygen in the water of the Buriganga is 2.2mg under Gabtali Bridge.
In addition, the amount of dissolved oxygen is very low due to water pollution in other rivers around Dhaka including Turag, Balu, Shitalakshya and Dhaleshwari.
According to a recent report of Institution of Diploma Engineers, Bangladesh (IDEB), at least 316 sources have been identified that pollute the rivers around Dhaka.
Wastes from various institutions including hospitals, tanneries, cement factories, dockyards, readymade garment factories and the two city corporations are being mixed through these sources into the river.
However, the environmentalists said that the rivers around Dhaka must be saved from pollution immediately. The authorities concerned as well as the city dwellers should be more careful about this matter, they added.