How Can Bhoj Wetland Address the Issue of Microplastics?

As you enter the city of Bhopal through the road that connects it to the airport, a lake, literally called Bada Talaab (big lake), welcomes you. Bhopal, one of the few cities ruled by four female rulers in the past, is also known as the city of lakes. A magnificent 5 km road called the VIP Road was built in the early 1990s to save the lake under the Bhoj Wetland Project. I have driven on this road several times, mesmerised by the great immensity of the lake. A few years later, when I visited Chicago, US, Lake Michigan gave me the same feeling. Though the latter is much bigger and in better condition.

Bhoj—named after the king who once ruled the city—wetland includes two man-made lakes: the Upper Lake (Bhojtal) and the Lower Lake (Chhota Talaab). The Upper Lake covers about 31 km² and provides nearly 40% of Bhopal’s daily drinking water. The Lower Lake covers about 1.29 km² and gets water from the Upper Lake. Together, these lakes form Bhoj Wetland, a Ramsar site since 2002. The wetland supports over 160 bird species and many aquatic animals. It helps protect biodiversity and offers recreation for people.

Bhopal’s lakes and microplastics

In February 2023, a group of scientists, including Surya Singh, collected bulk water samples from Bhoj Wetland using the grab sampling method. Singh, the principal investigator of the study, works at the Division of Environmental Monitoring and Exposure Assessment (Water & Soil), ICMR—National Institute for Research in Environmental Health, Bhopal.

They used 1-liter wide-mouth glass jars to avoid plastic contamination. This method was chosen because the lake is small, unlike larger rivers or oceans, where manta trawls or nets are commonly used. Samples came from different spots, including wastewater discharge points, dense macrophyte areas, and shallow water zones. To study the problem, researchers visited ten spots across both the upper and lower lakes. 

In the lab, samples were filtered through sieves, smaller particles were collected with metal forceps. Samples underwent density separation using a sodium chloride solution (1.2 g/mL) to float microplastics, which were then analyzed under a stereomicroscope for size, shape, and colour. Water samples showed up to 6.6 microplastic items per litre. The particles were mostly thin fibers, broken fragments, small foams, and flat sheets. Their sizes ranged from 0.4 to 4.7 millimeters—small enough to be swallowed by fish and other aquatic life. 

The researchers used a special machine called an FTIR spectrometer to identify the types of plastic. In the upper lake, the most common was polyethylene terephthalate (PET), a common material in bottles, along with polypropylene and some PVC. The lower lake had a wider range, including polyester and nylon.

The plastic particles smaller than 5 millimeters, referred to as microplastics, have been found in every place from rivers, fish, and breasts to even placentas (a developing fetus). The inefficient and not up-to-the-mark waste management has deposited our plastic waste into rivers, lakes, air, spills, and other places. From there, the particles weave into food webs: a plankton gulps here, a fish nibbles there, and in a bird’s beak later on. The scientists have found them to be present in our tap and bottled water as well. 

Filters fail to capture particles

In the research, some plastic pieces showed signs of breakdown. Plastic waste doesn’t disappear—it breaks down. Over time, sunlight makes it brittle. It fragments into tiny pieces, eventually turning into microplastics. These particles then get carried into stormwater drains and end up in the lakes.

Dr. Pradeep Nandi, the Director General of the National Center for Human Settlement and Environment (NCHSE) and Environmental Planning & Coordination Organisation (EPCO), said, “Microplastics are a very serious concern. They’re not visible to the naked eye. They’re nano-sized particles, much smaller than what sand filters can catch. These particles pass through our standard water treatment systems. Our water filters are not designed to trap them.”

Dr. Nandi joined the Bhoj Wetland Project in December 1998. At first, he was tasked with establishing a water-quality laboratory so the team could gather “good data” and understand the lake’s condition. Once the lab was running, he took on broader duties: clearing invasive water hyacinth, leading afforestation drives around the shoreline, and supervising each of the project’s sub-initiatives. As a member of the Project Review Committee, he watched the original 14 sub-projects grow to 21 and remained deeply involved at every stage.

He said that momentum and conservation measures slid once the project wrapped up. Encroachments multiplied—hotels, shops, and restaurants crowding VIP Road—and enforcement all but vanished. He still recalls approving Hotel Ranjit only after it installed its sewage-treatment plant, a standard no longer upheld. “It’s all tourism now,” he says, noting that he has stopped taking his morning walks by the lake altogether.

Last year, we reported on the ecological crisis facing Bhoj Wetland in Bhopal. The wetland, a Ramsar site since 2002, is under threat from rapid urbanisation and pollution. It receives nearly 44 million liters of untreated sewage daily. Sewage, toxins, and nutrient runoff from nearby farms worsen water quality. This damages habitats for 2,500 migratory bird species, fish, and turtles. Experts raised alarms about development projects in the lake’s catchment area decades ago. 

Despite petitions, construction continues near the wetland’s banks. The National Green Tribunal stepped in last year, halting motor-powered boats to reduce damage. Scientists warn that sewage treatment plants in Bhopal fail to stop harmful waste from entering the wetland. They call for better management of local resources like forests and grasslands to prevent silt buildup. Experts also recommend creating a 200-meter buffer zone and de-silting the lake. This will protect aquatic life and improve water quality. They stress combining conservation with urban planning to save Bhoj Wetland.

“We can’t recycle our way out of plastics,” a researcher on the toxic chemicals in plastic and recycled plastic told me. Recycling is ingrained in our minds as a solution to plastic. This might work for large plastic materials like PET bottles. But some kind of shredding will suspend very small plastic particles in the air. What about them?

Lately, we have more research on microplastics in our bodies and the atmosphere. What are the consequences? We know very little. But, for certain, they aren’t good. For instance, early research links microplastics to inflammation, immune system changes, and potential hormone disruption. Some plastics carry toxic chemicals or heavy metals that may increase health risks. 

Dr. Leepika Parulekar, consultant, general medicine, Holy Family Hospital, Mumbai, said, “The health risks of exposure to microplastics are just beginning to be understood.” 

Research has linked microplastics to colorectal cancer and the worsening of breast cancer metastasis. Dr. Parulekar noted, “A recent report described a potential link between their presence in blood vessels and cardiovascular disease.” She also highlighted findings related to inflammatory bowel disease: “The concentration of fecal microplastics was higher in people with inflammatory bowel disease than in healthy people, and the level correlated with the severity of the disease.”

In December 2024, the Union government trained doctors and researchers in health issues caused by microplastics. The Scheme for Promotion of Academic and Research Collaboration (SPARC) project focuses on teaching clinical researchers, environmentalists, and pharmacists how to identify microplastics in the human body and develop treatment strategies.

Dr. Thava Palanisami, one of the experts for the project from the University of Newcastle, Australia, said India doesn’t have enough researchers working on this issue, despite having a large population exposed to plastic pollution. “That’s why this project is very important for India,” he said.

Rethink sewage before discharge

Speaking on the current lake management in Bhopal, Dr. Nandi said, “Microplastic pollution is not even on the radar for those managing the lake. If it were a concern, we would have seen policies or actions addressing it by now.”

But there are solutions. Dr. Nandi mentioned one: membrane filtration technology. This system uses thin layers with tiny pores to separate pollutants from water under pressure. It blocks microplastics and other small particles, letting clean water pass. Dr. Nandi said, “it is expensive… And it also doesn’t work well when the water has high turbidity.” High turbidity clogs membranes, reduces their performance, and raises maintenance costs. 

Similarly, Dr. Faiyaz Ahmad Khudsar, environmental scientist and ecologist, emphasised the need to rethink how we handle sewage before it reaches rivers and wetlands. “Most people look at sewage treatment plants, but constructed wetlands offer a low-energy, effective way to treat sewage,” he said. “These systems can remove plastics and solid waste before water enters natural wetlands or rivers. This should be part of urban planning. Without proper sewage management, microplastics will continue to pollute our water bodies.”

Constructed wetlands are man-made shallow ponds made of vegetation, soil, microorganisms, water, and a substrate that helps absorb and remove nutrients and pollutants. They clean wastewater using natural processes. Wastewater moves slowly through shallow beds planted with wetland plants like reeds and sedges. Plants trap solid waste, including plastics. Microbes around the roots break down organic matter and nutrients such as nitrogen and phosphorus. The soil filters particles and absorbs extra nutrients. Together, these processes remove 60 to 75 percent of pollutants, including organic matter, nitrogen, and phosphorus.

Dr. Khudsar clarified, “Microplastics themselves do not shrink wetlands. However, sewage causes eutrophication—leading to excessive plant and algae growth—by introducing nitrates and phosphates. This leads to algal blooms and oxygen depletion, which harms water quality and aquatic life. Microplastics add another layer of long-term contamination.”

Plastic waste doesn’t disappear. It just breaks down. In Bhopal, a lot of it ends up in the lakes through drains and sewage. Without addressing upstream factors like turbidity and untreated sewage, even the best technologies can fall short. Dr. Khudsar said, “In my childhood, we had no plastic and used natural bags. We need to bring back those practices before it is too late.” Maybe, we shouldn't rely too much on technology and change our behaviour too.

In the next part, we discuss where the water from Bhoj wetland, laced with microplastics, is used. The contamination persists under the administration's radar, and indirectly we are impacted.

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