The Way Forward
Macroplastics are progressively fragmenting into smaller microplastics and nanoplastics which cannot be captured in routine monitoring studies. Ultraviolet light weakens plastic, and coupled with biological (bacterial fragmentation) or mechanical (wave energy) action, this can cause large items to fragment into micro- and nanoplastics . Further, it has been found that microplastics have accumulated in inaccessible and relatively under-sampled locations such as the deep sea, within the arctic ice and biota . Microplastics have also accumulated in beach sediments more than a meter underneath the sediment surface .
It seems probable that the eventual fate of all plastic in the environment is as microplastic- or nanoplastic-sized fragments. In some locations, microplastics are substantially more profuse in quantity than macroplastics. However, macroplastics are still the dominant size fraction by mass in the environment. Therefore, even if additional input of plastic debris into the oceans is prevented forthwith, the quantity of micro- and nanoplastics will continue to increase over time owing to fragmentation of legacy plastic items already present in the environment . It is also established that there are no effective resources for eliminating microplastics or nanoplastics once they are in the ocean. Hence, in addition to the quantification of microplastic and nanoplastic abundance and the consideration of their potential health and environmental effects, it is imperative to focus on developing methods to reduce the input of plastic debris into the ocean. Some countries have effected important changes in their legislations pertaining to plastic waste management and disposal in order to achieve the required cut in plastic input to oceans. For example, India amended its Plastic Waste Management Rules in 2018 to phase out all multilayered plastic (MLP) which is non-recyclable, non-energy recoverable or with no alternate use. Efforts are also being undertaken by the Indian government to enforce a complete ban on single-use plastics in the near future.
It is usually considered that with the exception of incinerated plastic, all the conventional (non-biodegradable) plastic that has ever been produced is still present on the planet Earth in a form that is too large in size to be biodegraded. Further, the rate of biodegradation of plastics is very slow, to the extent that biodegradation cannot be relied upon to have any useful effect on the vast quantities of plastic debris in the oceans .
The above facts point to an urgent need for undertaking concrete steps toward prevention of indiscriminate and irresponsible use of plastics around the world. Some important considerations that need to be made relating to the input of plastic debris into the marine environment are:
- • About 8% of the world’s oil production is utilized to produce plastic items . However, 50% of these items are discarded within a short time frame . Since the plastic products are inherently recyclable, it is possible to decrease the accumulation of plastic debris as well as the demand for fossil carbon by recycling end-of-life plastics.
- • A notable difference between the problem of marine plastic debris and several other existing environmental issues is that the emission of plastic debris to the oceans is not directly linked to the benefit. The benefits from plastics can be obtained without there being a need for end-of-life emissions of plastic to the marine environment .
- • While the relative importance of certain impacts caused by marine debris is debatable, there is typically universal consensus among scientists, industry representatives, policy makers and non-governmental organizations (NGOs) that the unchecked input of marine debris is detrimental to the economy, wildlife and the environment .
The solutions to the plastic menace are well-known and lie on land rather than at the sea. The problems that retard progress toward sustainable use of plastics relate to prioritizing the solutions at hand. Some potential solutions to ensure judicious use and minimal disposal of plastics are described as follows:
- • Reduction in the usage of plastic products leads to reduction in the amount of new plastic produced and ultimately reduces the potential for micro- or nanoplastic formation.
- • Reusing the plastic items directly reduces the need for new plastic items, thereby also reducing the quantity of end-of-life plastic material.
- • Recycling the end-of-life plastic material back into new items in a closed loop can simultaneously reduce the accumulation of waste and the demand for fossil carbon.
- • Recovering the energy potential of plastics by incineration helps in extraction of the value of plastic material that cannot be reused or recycled.