Subscribe
Microplastics travel across borders from cities to seas and back to human bodies.
They contaminate India’s coastlines, rivers, soils and food.
Microplastic are a pervasive public health and ecological threat that is extremely hard to control once released.
Plastic is recognised as one of the most exceptional materials due to its cheap cost, durability, easy access and viability. But tiny particles released by plastic degradation have become a major concern. Microplastics, tiny plastic particles smaller than 5 millimetres, have become a serious environmental threat because they are omnipresent in almost every other place, including rivers, oceans, soil, air, and even the food we eat and the water we drink.
The most worrisome thing about microplastics is not just their presence in food and water, but also their transboundary nature of travelling long distances across multiple environments, including land, sea, cities, nature or even in the human body.
Coastal areas and river systems have a huge role in the transportation of microplastics. Many research studies have proven that India’s eastern coastline is severely contaminated with microplastics, with them being found in seawater, beach sand, and commercially important fish species. Most of these areas have a high pollution hazard index, which is a clear sign of extreme ecological stress.
Recent studies along India’s eastern coastline recorded average microplastic concentrations of 80 ± 33 particles / m³ in seawater and 4 ± 2 particles / kg in beach sand, with the hazard index scores indicating several places in the most hazardous pollution categories.
It has also been found through various studies that about 30 per cent of commercially important fish species sampled from these coasts were found to contain microplastics, with polyethylene terephthalate (PET) and polypropylene being dominant polymers among them.
Rivers are one of the dominant routes for plastic flow and pollution. Poor waste management systems, untreated sewage and plastic litter release microplastics into rivers, which slowly end up in the oceans. So, what began as an unmanaged waste in the city can reach marine ecosystems thousands of kilometres away.
Baseline studies and measurements from South Indian rivers showed microplastic concentrations of 0.4 particles / litre in urban rivers, much more than found in rural rivers, which indicates the influence of human activity on urban rivers.
It is believed that wastewater treatment plants are a great solution for microplastic removal, and to a large extent, they do eliminate microplastics. However, these eliminated microplastics accumulate in the sewage sludge, which is commonly used as biosolids in agriculture and land rehabilitation.
And because of this, microplastics unintentionally end up on land from water, contaminating soils and groundwater. This way, an effort to manage waste intensifies the pollution instead of eliminating it.
Treatment methods like electrocoagulation, although designed to extract and remove more than 90 per cent of microplastics, have the ability to physically and chemically alter these particles. Studies prove that such methods may break down microplastics into even smaller particles, like nano plastics, which are more easily bioavailable to living organisms.
Soils that have been treated with long-term application of biosolids were found to contain up to 6.04 × 10² microplastic particles per kg, far higher than soils without the application of biosolids.
Microplastics have been found in a wide range of edibles, including food products like seafood, sea salt, drinking water, cooked meals and even the air we inhale. Research studies prove that food is the primary pathway through which humans uptake microplastics, followed by air and water.
Commercial sea salts in India were found to contain about 700 microplastic particles per kg. Urban pollution exposure studies indicate that Indians inhale an average of 2012 microplastic particles per person per day through food, air and drinking water combined.
Once they enter the body, microplastics release toxic chemicals like plasticisers and other emerging contaminants, which can cause grave health issues. Laboratory experiments have confirmed that microplastic exposure can lead to cellular stress, endocrine disruption, apoptosis and inflammation, which has left a great stress on its long-term health impacts.
Further, microplastics are transboundary, long-lasting and extremely hard to control if released in the environment.
Microplastic pollution is not just an environmental issue; it is a public health concern that has the capacity to affect everyone, irrespective of any social hierarchies. But major gaps exist in how we detect, track and evaluate the risks associated with microplastics.
There is an immediate need to develop standardised methods to detect system-based risk assessments and the development of strong policies that manage plastics throughout their life cycle. Minimisation of plastic waste, building strong waste management systems and redesigning the treatment technologies are key steps in limiting microplastic contamination.
Tackling microplastic pollution requires collective action from all concerned stakeholders — scientists, industries, policy makers and civil society — to protect and safeguard both environmental and human health.
Pondharshini Ponnusamy is pursuing MSc in environmental science and sustainability management at Bharathidasan University, Trichy, Tamil Nadu. Views expressed are the author’s own and don’t necessarily reflect those of Down To Earth.