How are micro plastics a concern for sea salts in India?

By Vivek Saini 

Over the past few years, the existence of microplastics in sea salt has been confirmed by numerous investigations conducted throughout India. Microplastic particles varying between 35 and 575 were discovered in a kilogramme of sea salt in different studies. 

A wide range of plastic items have been produced thanks to the plastic industry’s rapid expansion. Plastics’ potential to permeate the environment is increased by their widespread manufacture and use. 

The threat of plastic pollution to the earth’s climate has increasingly been recognised as plastic trash production has increased.

How does (micro) plastic contribute to climate change? 

Plastics are manufactured with the use of fossil fuels. The greenhouse gas (GHG) emissions produced by the many processes involved in the life cycle of products made of plastic pose a serious threat to the environment because they increase the rate at which the earth’s temperature rises. Every phase of the plastic life cycle, including the extraction and transportation of raw materials, plastic manufacturing, waste treatment, and environmental release, has been shown to produce greenhouse gas emissions.

Up to 13% of the carbon budget for our planet will be consumed by plastic manufacture by 2050. The remaining carbon reserves on Earth have been exhausted as a result of global GHG emissions, which have also created an unsettling feedback cycle. GHG emissions increase as a result of inadequate management of plastic garbage and its accumulation on riverbanks, coasts, and other natural areas.

Every phase of the plastic life cycle, including the extraction and transportation of raw materials, plastic manufacturing, waste treatment, and environmental release, has been shown to produce greenhouse gas emissions.

The ability of the ocean to fix carbon will be severely hampered by the presence of microplastics in the water due to the delayed release of greenhouse gasses from plastics into the environment. By 2030 and 2050, respectively, the greenhouse gas emissions caused by plastics from cradle to grave will amount to 1.34 gigatons per year and 2.8 gigatons per year, The ability of the international community to keep global temperature increases at 1.5 °C or even 2 °C by 2100 will be gravely threatened by this serious consumption of the remaining carbon budgets. 

How do microplastics get accumulated in Indian sea salts? 

Ocean ecosystems are gravely concerned about plastic contamination. Although it is difficult to assess the amount of plastic dumped into the ocean with certainty, estimates show that at least 14 million tonnes of plastic enter the ocean annually. In the next two decades, the amount of plastic is expected to significantly increase if nothing is done.

The discovery of microplastics (plastic particles smaller than 5 mm) in a variety of marine animals, including fish, mussels, and crustaceans, has brought the pervasiveness of plastic contamination in the marine environment into sharp light in recent years.

Despite being thought of as nearly indestructible, plastic does fragment in the environment when exposed to ultraviolet light and outside pressures, leading to mechanical and biological degradation and the creation of smaller plastic particles. 

The omnipresence of micro plastics and their effects on the sea derived products

2018 saw the publication of a first-of-its-kind (in India) research article by Chandan Krishna Seth and Amritanshu Shriwastav from the Centre for Environmental Science and Engineering at the Indian Institute of Technology (IIT) Bombay on the identification and assessment of microplastic particles from commercial Indian salt samples. With counts ranging from 56 to 103 particles per kilogramme of the salt sample, Seth and Shriwastav discovered microplastics in every sample.

The analyzed samples contained both fibers and fragments, with fragments making up the majority of the observed microplastic population. The scientists also investigated the microplastics’ chemical makeup and found that polystyrene, polyamide, and polyethylene were present, as well as polyesters like polyethylene terephthalate (PET) and others.

In the same year, a survey by Greenpeace East Asia found that 90% of the world’s table salt brands included microplastics, with one Indonesian sample being the most contaminated of the lot. The nation is second in the world in terms of its contribution to marine plastic pollution. Only three of the 39 samples that were examined revealed a lack of microplastics, illustrating how widespread the problem is. According to the study, an adult could typically ingest 2,000 microplastic particles annually from their salt intake.

How many Microplastics are there on our dining table? 

India is one of the top producers of salt in the world. The nation produced 45 million metric tonnes of salt in 2022, coming in second to China’s 64 million metric tonnes. For Indian salt producers, seawater is a supplier of salt. Researchers at the Suganthi Devadason Marine Research Institute in Thoothukudi studied seven samples of sea salt and seven samples of salt made from borewell water and found microplastics in all of the salt samples, which is similar to the 2018 IIT Bombay study. The microplastic content of sea salt samples ranged from 35 to 72 pieces per kilogramme, while borewell salts had substantially lower counts, between 2-29 items per kilogramme, supporting the high levels of pollution in seawater.

In a subsequent study conducted in 2021, A. Vidyasakar et al. examined crystal and powder salt samples from Tamil Nadu and Gujarat and discovered microplastic levels ranging from 23 to 101 particles per 200 g (in Tamil Nadu salts) to 46 to 115 particles per 200 g (in Gujarat salts). Like their forerunners, Vidyasakar et al. detected the presence of polyvinyl chloride in addition to polyethylene and polyester.

How does it affect humans?

Due to their various physical-chemical characteristics, which make microplastics multifunctional stressors, it is extremely complicated to comprehend their influence. Microplastics are a mix of dangerous compounds, which makes them both carriers of toxic substances in ecosystems and carriers of poisonous chemicals themselves. 

“We also need to keep in mind that sea salts are just one of the many sources through which we now ingest microplastics,” explains Shriwastav. Microplastics have also been found in fruits-vegetables, water, and the air we breathe in addition to being present in seafood.

He also added, “While direct consumption of salt may not expose one to large amounts of microplastics, we see exposure to higher concentrations if we combine all the possible routes. Unless we have health risk assessments factoring in all these routes of entry and the resulting dose, it would be difficult to comprehend the effect,”

References:

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Image source: https://india.mongabay.com/2023/04/varying-levels-of-microplastics-detected-in-sea-salt-produced-across-india/