Why in News:

• Microplastic pollution has been detected in human blood for the first time. The study, published in the journal Environment International, tested 22 anonymous blood samples.

What are microplastics?

• Microplastics are tiny bits of various types of plastic found in the environment. The name is used to differentiate them from “macroplastics”  such as bottles and bags made of plastic. There is no universal agreement on the size l — the U.S. NOAA (National Oceanic and Atmospheric Administration) and the European Chemical Agency define microplastic as less than 5mm in length.
• The researchers have an upper limit on the size of the particles as 0.0007 millimetre.
• Microplastics are divided into two types: primary and secondary.
  • Primary microplastics are tiny particles designed for commercial use, such as cosmetics, as well as microfibers shed from clothing and other textiles, such as fishing nets.  Microbeads(used in personal care products), plastic pellets, and plastic fibres are some of the examples.
  • Secondary microplastics are created when bigger plastics, such as water bottles, degrade. Exposure to external stimuli, namely the sun’s rays and ocean waves, causes this disintegration.

What the researchers found

• The study looked at the most commonly used plastic polymers. These were polyethylene tetraphthalate (PET), polyethylene (used in making plastic carry bags), polymers of styrene (used in food packaging), poly (methyl methylacrylate) and poly propylene. They found a presence of the first four types.
• The discovery shows the particles can travel around the body and may lodge in organs.
• The study found that 77% of tested people (17 of the 22 persons) carried various amounts of microplastics above the limit of quantification.
• Half the samples contained PET plastic, commonly used in drinks bottles. While a third contained polystyrene, used for packaging food and other products. Some of the blood samples contained two or three types of plastic.
• Microplastics were also observed to cause damage to human cells in the laboratory.

What is the significance of the study?

• Making a human health risk assessment in relation to plastic particles is not easy,  due to the lack of data on exposure of people to plastics. Hence, this study the first step.
• Validated methods to detect the tiny amounts of extremely small-sized (less than 10 micrometre) plastic particles are lacking. Hence this study, which builds up a method to check the same, is important.

Negative impact of Microplastics

• • It is not yet clear if these microplastics can cross over from the bloodstream to deposit in organs and cause diseases.

• Air pollution particles are already known to enter the body and cause millions of early deaths a year and plastic particles that are of similar size may also cause the same problem.

• The researchers point out that the human placenta has shown to be permeable to tiny particles of polystyrene.
• Oral administration of microplastics in rats led to accumulation of these in the liver, kidney and gut.
• Microplastics cause damage to human cells in the laboratory.
• A recent study found that microplastics can latch on to the outer membranes of red blood cells and may limit their ability to transport oxygen.
• Microplastics have been detected in marine organisms from plankton to whales, in commercial seafood, and even in drinking water.
• Standard water treatment facilities cannot remove all traces of microplastics.
• Microplastics in the ocean can bind with other harmful chemicals before being ingested by marine organisms.
• The particles have also been found in the placentas of pregnant women, and in pregnant rats they pass rapidly through the lungs into the hearts, brains and other organs of the foetuses.
• Deep sea hotspots of biodiversity are also likely to be microscopic plastic hotspots. Thermohaline driven currents can cause microplastics in the same regions where underwater flock in the benthic zone (Because currents also supply oxygen and nutrients to the deep sea benthos)
  • Deep-ocean currents are driven by differences in the water’s density, which is controlled by temperature (thermo) and salinity (haline). This process is known as thermohaline circulation.
  • Organisms that live on the seafloor are called benthos. Most of these animals lack a backbone and are called invertebrates. Typical benthic invertebrates include sea anemones, sponges, corals, sea stars, sea urchins, worms, bivalves, crabs, and many more.

Initiatives related to reducing plastic pollution

• The Extended Producer Responsibility concept was introduced by the Plastic Waste Management (Amendment) Rules 2018.
• According to the Plastic Waste Management Rules of 2016, every local body must put up infrastructure for the segregation, collection, processing, and disposal of plastic waste
• Elimination of Single-Use Plastic: India committed in 2019 to abolish all single-use plastic in the country by 2022.
• Un-Plastic Collective (UPC) is a voluntary project sponsored by UNEP-India, the Confederation of Indian Industry, and the World Wildlife Fund-India.
• The 1972 London Convention on the Prevention of Marine Pollution by Dumping Wastes and Other Matter was signed to regulate the dumping of waste materials into the sea in order to manage all causes of marine contamination and prevent pollution of the sea. The Collective aims to reduce the negative effects of plastics on our planet’s ecological and social health.
• Plastics Pacts are business-led efforts aimed at transforming the plastics packaging value chain across all forms and products.
• The Global Partnership on Marine Litter (GPML) was established in response to a request made in the Manila Declaration at the 2012 Earth Summit.

References:

1. https://www.downtoearth.org.in/video/pollution/microplastics-detected-in-human-blood-for-the-very-first-time-82111
2. https://www.thehindu.com/sci-tech/science/detecting-microplastics-in-human-blood/article65267369.ece
3. https://www.theguardian.com/environment/2022/mar/24/microplastics-found-in-human-blood-for-first-time
4. https://www.thehindu.com/sci-tech/science/scientists-find-microplastics-in-blood-for-first-time/article65261875.ece
5. https://www.nationalgeographic.org/encyclopedia/microplastics/