Microplastics, Environment and Human Health
Plastics and plastic products being easily mouldable, chemical resistant, easy to manufacture, light easy to transport, useful and cheap are everywhere. One can see widespread use of plastics in food packaging, building and plumbing accessories, electronic products, medical equipment and accessories and in almost all other fields in some way or the other.
Non-biodegradable plastics and plastic products, being persistent in the environment are a major area of concern. Ironically, they have a very small functional life span but may remain in the environment for hundreds of years.
The Government of India has been concerned about the disposal of plastics and regulates plastics through the Plastic Waste Management Rules 2016 as amended. Some important amendments include the amendments of 2018, 2021, and two amendments in 2022, one of which also includes the E.P.R. guidelines for plastic waste disposal. These rules, prescribed under the E.P. Act of 1986, entrust various responsibilities on Local Bodies, Pollution Control Boards, Generators, Manufactures, Producers, Brand owners and Importers. (See Also: The Plastics Waste Management Rules were notified in 2016 (G.S.R. 320 E dated 18/03/2016) and have been amended in 2018 (G.S.R. 320 E dated 27/03/2018); 2021 (G.S.R. 571 E dated 12/08/2021); 2022 (G.S.R. 133 E dated 16/02/2022); 2022 (G.S.R. 522 E dated 06/07/2022); and 2024 (G.S.R. 201 E dated 14/03/2024)).
Waste generators must ensure that plastic waste is not littered and is stored and segregated before disposal as prescribed through the Municipal Solid Waste Handling Rules and disposed only through authorized vendors.
Producers of Carry bags must ensure that the thickness of carry bags is not less than 120 microns. It has also to be ensured that the producers, brand owners, importers or manufactures and the recyclers are duly registered with the Pollution Control Boards. The rules prohibit the use of recycled plastic for carrying or storing food. Single use plastics like earbuds, plastic sticks for balloons, plastic flags, candy sticks, ice cream sticks or thermocole for decoration are banned since 2021.
The rules entrust the producers, manufacturers, importers and brand owners with the responsibility for managing the end-of-life disposal of plastics introduced by them in the market. It also provides for environmental compensation in the event of noncompliance to rules. End of life disposal has been construed to mean using plastic waste for the generation of energy including co processing, waste to oil and road construction etc. as provided. Of late, the rules have been amended to provide for biodegradable and compostable plastics. “Biodegradable plastics”, means plastics, other than compostable plastics, which undergoes degradation by biological processes in specific environment such as soil, landfill, sewage sludge, fresh water, marine, without leaving any micro plastics or visible or distinguishable or toxic residue, which has adverse environment impact,” and “compostable plastics” mean plastic that undergoes degradation by biological processes during composting to yield CO2, water, inorganic compounds and biomass at a rate consistent with other known compostable materials, excluding conventional Petro-based plastics, and does not leave visible, distinguishable or toxic residue.
Microplastics are generally defined as plastic particles between 1 nanometer (nm) and 5 million nm (or 5 millimeters [mm]) in size. Particles larger than 5 mm are often referred to as macroplastics while particles less than 1 nm are considered nanoplastics, a subgroup of microplastics. Micro plastics are a major area of concern. In comparative terms they are generally regarded as being the size of a grain of rice to 1/80000 width of human hair. Their problem is again that they are persistent in the atmosphere, they absorb toxins and other chemicals from the environment and release constituent chemical products.
Microplastics may harbour microorganisms which may be pathogenic, and the chemicals transferred by them to the environment may enter the food chain, bio magnify and impact the sink biota. Microplastics have been found in all biotic and abiotic components of the ecosystem which have been exposed to plastics and where plastics are used and disposed. They may enter the soil through sewage sludge (where they reach after escaping through S.T.P.’s or through raw untreated sewage). They may become air borne being introduced through traffic (tyres) or through abrasion of plastics used in Road Construction (?), industrial processes, erosion of contaminated soils and action of wind.
Micro and Nano particles are major pollutants effecting rivers and oceans.
Microplastics, depending on their origin, may be either primary or secondary.
Primary microplastics include tiny particles for commercial use (Nurdles), Microfibers shed from textiles and clothing, microbeads in personal care products like cosmetics, exfoliating creams, toothpastes etc., plastic pellets and plastic fibres and the like.
Secondary micro plastics are degradation products of larger plastics due to degradation and disintegration. Some examples are microplastics generated from toothbrushes (change tooth brush every month), tyre dust, construction debris, plastic mulch in agriculture and plastic covers including green house covers.
More than 10000 unique chemicals are associated in plastic manufacture out of which 2400 are identified as chemicals of concern and which find their way into the ecosystem through disposal and dispersal of micro plastics.
As stated, microplastics act as carriers for various chemicals, antibiotic resistant bacteria and pathogens and create enormous health and other ecological impacts if discharged in an improper way without treatment. They may absorb and concentrate harmful chemicals from the surrounding water such as pesticides, heavy metals, other persistent organic pollutants which may bio accumulate as they move up the food chain posing health hazards.
Micro plastics impact ocean ecology. Marine biota, from plankton to whales are exposed to micro plastics either directly or indirectly. Ingestion of microplastics may cause physical harm, block digestive tract and lead to malnutrition and starvation. Also, micro plastics can bioconcentrate in various issues. It has been reported that over 60% species in the North pacific had ingested plastic debris. Settling on the sea bed may also affect benthic organisms and smother small marine life. It may affect the feeding and reproduction behaviours. Coral reefs may be affected through reduced growth impacts and a reduction in resilience.
Micro plastics in soil affect the soil water retention and microbial communities causing a reduction in crop yield and fertility. Agricultural lands using plastic mulch and sewage sludge as fertilisers are particularly vulnerable. Microplastics can also enter plastics through roots and get incorporated into the food chain leading to both plant and human level impacts.
In relation to impacts on humans, microplastics have been found to be accumulating in human brain and other body organs. In postmortem investigations, brain has been reported to contain up to a spoon full of micro and nano plastics. Brain tissues have 7 to 30 times more micro and nano plastics than in other organs like the liver or kidney. Microplastics have also been found in human placenta and the meconium, affecting foetal-maternal exchanges. Micro plastics affect male and female fertility and epigenetic formatting and Oocyte health. Impaired spermatogenesis has also been observed. Microplastics exposure can lead to adverse health impacts via oxidative stress, inflammation, immune dysfunction, altered biochemical/energy metabolism, impaired cell proliferation, abnormal organ development, disrupted metabolic pathways and carcinogenicity. People with a carotid artery plaque, where microplastics have been found, have a higher risk of myocardial infarction, stroke and increased mortality.
Learning and memory deficits have been observed along with lower levels of synaptic proteins and neuro inflammation in mice exposed to nano plastics.
Human exposure to microplastics occurs through food, water, air and dermal contacts.
The following have been suggested as actions to minimize generation of microplastic in the Environment.
- Switching from bottled water to tap water could reduce Micro and Nano particle intake from 90000 to 4000 particles per year.
- Stopping heating of food in plastic could be very effective in limiting microplastics. Choose fresh and unprocessed food.
- Limiting canned food consumption and opting for non-plastic packaging alternatives.
- Avoiding plastic utensils.
- Using loose leaf tea with a stainless steel or glass infuser.
- Avoid throwaway cups and cutlery.
- Choose natural skin care and beauty products free from micro beads. Change Toothbrush every month.
- Washing synthetic clothes in a micro fiber filtering laundry bag or using a washing machine filter.
- Reduce plastic use
- Shun single use plastics which is banned in India.
- Use biodegradable alternatives
- Encourage recycling.
- Step up waste management.
- Clean up contaminated areas.