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Emerging pollutants in water pose risks

SM NAJMUS SAKIB | September 08, 2022 00:00:00

An alarming presence of emerging pollutants (EPs) in surface water becomes a new threat to the environment and health for incapacity to treat industrial and household sewage waste in Dhaka.

Bangladesh is suffering from excessive environmental pollution due to increased anthropogenic or human-induced activities.

EPs, which include products such as antibiotic, detergent, toothpaste, shampoo and lotion, in addition to the growing pollution are affecting nature and contaminating the food chain.

A new study traces such EPs in lakes and river waters of Bangladesh with intensity higher than other developed and underdeveloped countries.

The EPs are this considered a serious concern to the ecosystem and human health, it says.

The study styled 'Identification and characterisation of sources and fate of emerging pollutants (EPs) in surface water of Bangladesh using three-dimensional excitation-emission (3DEEM) spectroscopy' was published in the 'Journal of the Bangladesh Chemical Society' earlier this month.

First author of the study Nahin Mostofa Niloy said they earlier studied the Ganges for a year and found high presence of detergent or whitening agent both in its Bangladesh and Indian parts.

"As part of it, we examined the Turag and some seven lakes on the Jahangirnagar University (JU) campus to find if the surface water in those areas carries emerging pollutants," he told the FE.

"We collected water samples from the Turag in three different seasons and found shampoo and lotion as there are industries along the river."

The research team found an alarming level of antibiotic in the water of a lake close to the JU medical centre while other lakes carry EPs like detergent, toothpaste, antibiotic, Mr Niloy added.

"This contamination occurred through sewerage line," he said, emphasising the installation of water and sewerage treatment plants as found in developing countries.

Environment and waste expert Prof Dr Shafi Mohammad Tareq of JU told the FE that these emerging pollutants reach urban rivers and other surface water sources from factories and household sewerage lines.

The co-author of the study said, "We, in many cases, are to use whitening agents and detergents in industries, especially in dyeing factories. What we can do is to control its use to keep it at a permissible level and install water and sewerage treatment plants."

Treatment plants are needed to treat liquid chemicals and water before they harm the environment.

Another major concern is the alarming presence of antibiotics in surface water. Untreated sewage water from hospitals gets mixed with surface water sources and contaminates them.

"Human body absorbs some 40-50 per cent of a single dose of antibiotic while the remaining part is found alive in human waste. Bacteria can be resistant when antibiotics come to nature in such a process," said Prof Tareq.

In such a way, bacteria are introduced with antibiotics in nature and become resistant and powerful against antibiotics. Finally, we become vulnerable to diseases caused by bacteria," he explained.

A recent ICDDR,B study found that hospitals countrywide were admitting more and more young children with pneumonia with high resistance to standard antibiotics.

Hospitals in Bangladesh become a hub for anti-microbial resistance, certainly during the Covid pandemic due to random use of antibiotics that reduced effectiveness up to 50 per cent, according to a study of the Institute of Epidemiology, Disease Control and Research.

Experts said overuse of antibiotics in agricultural, animal husbandry or fish farming also releases untreated antibiotics and chemicals to surface water and has similar effects.

Food chain is also contaminated in this process. When an untreated antibiotic reaches surface water sources, lives in the water can house antibiotics in their body and get returned to the human body through the food chain like having contaminated fishes.

"Thus, an improper waste management or lack of sewerage treatment plants, these remaining alive antibiotics, personal care items like toothpaste, shampoo, lotion end up with the environment," Prof Tareq added.

"Earlier, we did not consider those EPs as pollutants but it is high time to pay proper attention," he emphasised.

Department of Environment director (Dhaka zone) Ziaul Haq told the FE that industries are supposed to use effluent treatment plants (ETPs) to treat industrial liquid before releasing it to the environment.

"We regularly monitor if factories install ETPs, but we cannot monitor fully because of manpower shortage while many factories are reluctant to use ETPs which could leak untreated waste to the environment."

Dhaka Water Supply and Sewerage Authority (WASA) can hardly manage 30-40 per cent household sewage waste and the rest reaches surface water untreated.

"So, we have to increase our capacity to deal with the emerging pollutants," Mr Haq asserted.

He also called for sensitising people to the harmful effects of the use of heavy metal-containing care products as chemicals are harmful to skin and health.

"To cover and manage this massive task and ensure a safe environment, we need a concerted effort by the local government authorities, city corporations and WASA," he concluded.

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