Microplastic pollution of the marine environment

Introduction

One of the most acute pollution problems is microplastic pollution in oceans and inland waters, which affects not only the aquatic environment but also humans. Of the types of marine pollution (hydrocarbon pollution, heavy metal pollution, POP pollution – persistent organic pollutants, nutrient pollution) the most dangerous is microplastic pollution. People are potentially exposed to microplastics through food, drink and air. Microplastic pollution is a major type of pollution in all water bodies and a significant concern of the 21st century, requiring proper public awareness and rapid remedial action. Pollution with non-biodegradable microplastics is due to the presence in the crushed state of 3 of 27 types of polymers (PET-polyethylene terephthalate, PP-polypropylene, PE-polyethylene).

The term “microplastic” began to be used after the discovery and recognition of the threat posed by plastic fragments to the environment. Microplastics are plastic particles with dimensions between 5 mm and 1 nanometer; particles smaller than 1 micron are called “nanoplastics”. Plastics are generally difficult to biodegrade (in decades) or do not biodegrade, but decompose into smaller and smaller pieces, resulting in microplastics. Excessive disposal of plastics into water resources results in fragments generated by microscopic particles called microplastics.

Microplastic pollution is particularly complex: plastics are now observed in some of the most remote regions of the Earth; they occur mainly in the water of rivers, streams and migrate to the seas and the Planetary Ocean. Plastic waste crumbles slowly, reaching very small dimensions and interacts strongly with the environment and especially with biodiversity.

Fig.1 Marine pollution with microplastics

Plastic waste present in the marine environment is a threat to both the environment and marine life, being swallowed by living things in the marine environment. The impact of microplastics on the marine environment depends on physical behaviors (migration, sedimentation and accumulation), chemical behaviors (degradation and adsorption) and bio-behaviors (ingestion, translocation and biodegradation). The particularly serious problem is that microplastics are transmitted along the entire food chain reaching the top of the food chain (respectively in the human body).

Ingestion of water in which microplastic particles are present is the main cause of contamination of marine organisms. Microplastic particles can be ingested by marine invertebrates confused with plankton due to their similar size.  Zooplankton is then consumed by fish that will be contaminated in this way to which is added direct contamination from the water.  Animals that consume fish with microplastic particles will also be contaminated, the process being repeated to the top of the trophic pyramid (respectively to the human body).

The existing situation

The situation of the Black Sea is special due to the fact that it is a large semi-closed that finally collects the waters of the Extended Hydrographic Basin with rivers such as the Danube, Dniester, Dnieper which in turn collects wastewater and significantly polluted with microplastics resulting from activities inhabited by hundreds of millions inhabitants of Central and Eastern Europe. Under these conditions of excessive microplastic pollution, Black Sea water has reached an amount of about 10 plastic microparticles per liter of water.

World plastics production has grown exponentially since the early 1950s and reached 322 million tonnes in 2015, this figure does not include synthetic fibers which amounted to 61 million tonnes in 2015. Plastics production is expected to increase in the future so it is likely to double by 2025. Inadequate management of plastic waste has led to increased contamination of freshwater and marine environments. It is estimated that in 2010 between 4.8 million and 12.7 million tonnes of plastic waste went into the oceans. Plastics constitute between 60 – 80% of the waste present in the marine environment, and 90% of the waste floating on the seas and oceans.

Since mass production of plastic began 60 years ago, mankind has produced more than eight billion metric tons of plastic. Only 9% were recycled, another 12% incinerated. The rest, almost 80% of the plastic ever created, collects in landfills or ends up in the natural environment, eventually reaching rivers, streams and oceans.

Plastics of all sizes have become the most dominant form of marine litter and it has been estimated that at least 5.25 trillion plastic particles weighing over 268,000 tonnes have been dumped into the oceans1. In addition, according to the 2017 United Nations Environment Assembly (UNEP), an estimated 4.8-12.7 million metric tons of plastic are introduced into the oceans annually.

Once plastics enter the ocean, they break into microplastics by photolytic, mechanical and / or biological degradation. Several studies on the abundance and distribution of plastic size have shown a permanent fragmentation of the microplastic from larger to smaller, to nanoplastics (<25 μm), which occur continuously in the oceans.

Plastic particles of all sizes in the range also contain additives and other anthropogenic contaminants, such as organic chemicals that are adsorbed from the surrounding seawater. These pollutants include persistent, bioaccumulative and toxic substances (PBT), such as polychlorinated biphenyls (PCBs) and dioxins.  In addition to being non-nutritive and indigestible, plastics have been shown to concentrate pollutants up to a million times their level in the surrounding seawater and then deliver them to the species that ingest them.

Fig.2 Microplastics in the Black Sea sediments

Assault of microplastics

Plastic pollution is detrimental to the fertility, growth and survival of marine life. Very small particles (nanoplastics) are particularly worrying because they are the same size as the food consumed by zooplankton, which are the basis of the marine food chain and play an important role in regulating the global climate. New data suggest that there may be more microplastic particles in some waters than zooplankton.

Contaminating the entire food chain, the effects of the bioaccumulation of microplastic particles on marine biodiversity and ultimately on the human body are worrying. These microplastic particles have the greatest potential to cause the most harm to the oceans, rivers and lakes and ultimately to human bodies. It has been shown that microplastics can affect the immune system, can cause various imbalances in the intestine. inflammation, oxidative stress and even neurotoxicity.

We are assaulted by plastic microparticles, which are found in food, in drinking water, in sea salt. Pollution of the environment and especially of the marine environment causes food consumed by humans to be increasingly polluted. It is currently unknown exactly what the impact of microplastic ingestion is on the human body, nor what is the maximum amount tolerated by it.

The effects of microplastic ingestion were classified by researchers into three stages:

-a) the first stage is related to the blockage and damage of the digestive tract,

-b) the second stage concerns the release of toxic chemicals into the body,

-c) and the third stage is represented by the assimilation and accumulation of these substances by organs and tissues.

Ingestion of microplastics can also result from the consumption of lower organisms, which in turn have ingested microplastics. In order to determine the risk that these particles pose to the human body, it is important to determine the amount of microplastic that we may ingest with food.

Sources of microplastics

Thus plastic microparticles can come from:

-food 50.000MP / year 140MP / day

-drinking water 4,000MP / year 11MP / day 5-6MP / L

-bottled water 16.000MP / year 44MP / day 25MP / L

In addition to consuming marine animals, such as shrimp, mussels, certain fish, dozens of other microparticles can be added:

-a serving of 200g shrimp has 140MP

-a medium portion of 200g has 80MP

The degree of contamination of sea fish is very high in some areas reaching from 10% to 29% in areas close to urban areas.

Basically in a few months we swallow an amount of plastic equivalent to the weight of a bank card.

Preventive and corrective measures

Given the serious situation, preventive and corrective measures should be taken at national, international and consumer levels to assess the toxicity of common polymers, reduce the use of plastics and encourage the use of alternative materials, recycling and the adoption of sustainable practices in the use of materials. plastics and plastic pollution management.

To address this challenge, organizations such as UNEP have engaged more than 100 countries in educational campaigns to raise awareness of plastic pollution and to encourage the reuse and recycling of plastics.

Other international cooperation programs have been set up to address marine litter, including microplastic pollution. In 2015, the United States passed a special law banning the manufacture and distribution of rinsing cosmetics containing plastic microparticles. Many other countries have also imposed bans on the use of plastic microparticles in the cosmetics industry and taken measures to minimize the release of microplastics from textiles, tires, paints and cigarettes. In the European Union, only about 30% of plastic waste is collected for recycling.

In 2018, the EU banned certain single-use plastic products, which end up as waste in the seas and for which alternative materials already exist, and a European plastic strategy was established in September 2018, which requires that all packaging in the EU plastic to be recyclable by 2030.

Oxo-degradable plastics have also been added to the list of items to be banned. These are materials that break easily into small pieces due to additives and contribute to the pollution of the oceans with microplastics.

However, measures are needed to stimulate recycling and increase the market for recycled plastic.

These measures would include:

-creating quality standards for secondary plastics;

-encouraging certification to increase industry and consumer confidence;

-introduction of mandatory rules on the minimum recycled content in certain products;

-encouraging Member States to consider reducing VAT on recycled products

Conclusions

 Microplastic pollution is a real threat to any life on our planet. Although there is no clear and complete information on the effects they have on humans, the current data are sufficient to give cause for concern about this phenomenon and to stimulate researchers to look at this topic of general interest.

Animals that filter seawater to feed on plankton, such as whales and basking sharks, ingest hundreds, even thousands of cubic meters of seawater a day that contain microplastic particles. Also, the fact that it is known exactly what are the sources of this pollution forces the authorities and even the population to take urgent measures to reduce the amount of microplastics that is released into the environment at any given time.

Human populations use the sea as landfills, and microplastic is one of their main components globally.

Microplastic contaminants are ubiquitous in almost all marine environments. The durability of plastics determines a very high resistance to degradation, and by non-selective elimination it enters the aquatic environment.

There is currently a growing scientific concern about microplastics, as these microparticles due to their small size are easily accessible to a wide range of aquatic organisms and eventually transferred along the food chain. The chronic biological effects on marine organisms result from the accumulation of microplastics in their cells and tissues. Potential effects on humans caused by ingestion of plastic microparticles can cause chromosome alteration that could lead to infertility, obesity and cancer.

For this reason, it is very important that the excessive use of plastic additives be controlled and that legislative provisions be introduced to regulate plastic waste sources. And this can be done by configuring the various processes of plastic recycling or by promoting awareness programs, through various social and informational media, on the danger that plastic has on the food chain.

Bibliography

 Ivar do Sul, Juliana A .; Costa, Monica F. (February 2014). “The present and future of microplastic pollution in the marine environment”. Environmental Pollution. 185: 352–364;

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Author: Muntoiu Alexandru – ECOM Team Romania