Microplastics, a Contaminant of Emerging Concern
Microplastics are defined as plastic particles ranging in size from 1nm (nanometer) to 5mm (millimeter) and can be found in every ecosystem on the planet (U.S.-EPA). Although microplastics are present in all types of ecosystems inclusive of particles in air, soil and waters, it is the aquatic ecosystems that are often most associated with the presence of microplastics. These tiny particles (and many larger) can typically float and may congregate in eddies, tidal pools or wash up on beaches, making them obvious to the human eye. The most common microplastics, also known as synthetic polymers, that are found in aquatic environments are;
Polyethalene, polypropolene, polystyrene, polyamide, polyester and acrylics.
These polymer particles and pieces that are left behind as pollutants in the waters could have once been composed within paints, plastic bags, plastic water bottles, styrofoam, cosmetics, plastic toys, dust and other particles left behind from rubber tire wear or from just about any other polymer based products. Once these products have been discarded or cast off, they begin to degrade, weather and ultimately disintegrate leaving behind very small particles that can sometimes be so small that they are not visible to the naked eye. The smallest of these particles are known as nanoplastics, but they together with their larger counterparts are equally and perhaps even more of a hazard to the environment and living organisms.
What are some of the hazards associated with microplastics and nanoplastics?
The smallest of particles that are in the classification of nanoplastics can become hazardous when introduced into drinking water supplies and consumed by people. Nanoplastics can also be absorbed or ingested by very small living organisms such as plankton or settle upon vegetation that can later be ingested by other small organisms within the food web. From there, these small organisms may be consumed by other larger life forms such as minnows, crustaceans or amphibians, and so on up thru the food web to the next level of consumers such as larger fish, birds, animals and ultimately humans. The accumulative effect of ingesting these particles may eventually lead to health problems associated with either the chemicals or the particles themselves due to their physical properties or from bacteria they may carry upon their surfaces. Although the toxic effects to fish and humans are not well known, some studies have suggested that microplastics injested by fish can cause tissue damage, oxidative stress, immune related gene suppression, growth retardation and behavioral abnormalities.¹ Others effects on wildlife have been reported such as starvation when a plastic object blocks a digestive track in the consuming fish or animal, or even suffocation when a sea turtle mistakenly eats a plastic bag floating in the sea, as these bags can mimmick a jellyfish when submerged. Other discarded plastics such as the rings used to secure a 6-pak of cans have been found to suffocate fish, birds and mammals such as when the plastic gets caught around the head or neck of a fish, animal or bird.
In humans, microplastics can potentially cause oxidative stress, cytotoxicity, neurotoxicity, immune system disruptions and the potential for transfer of these particles to other tissues following exposure.¹ A less obvious hazard from microplastics is that when found in aquatic ecosytems they have a potential to act as a vector in transporting bacteria. Microplastics are often found suspended and floating and have surface areas with physical configurations that can support the harboring of bacteria, diseases or the carrying of invasive species which can then be transported to other areas by way of currents and wave action. This can lead to the introduction of invasive species, bacterias or diseases into habitats and spread among species that have not been previously exposed to such things.
What steps have been taken to help reduce microplastics from entering the environment?
Many countries around the world recognize microplastics as a pollutant and some have taken steps to address the issues associated with the presence and introduction of these particles into the environment. In 2015, the Unites States passed the Microbead-Free Waters Act which was aimed at preventing the introduction of microplastic beads into the waters of the U.S. by eliminating the production of cosmetics containing “rinse-off” microbeads. Other countries including Canada, France, New Zealand, Sweden, Taiwan and the United Kingdom also enacted similar laws aimed at banning the use of plastic “rinse-off” microbeads found in cosmetics. In 2020, California enacted the first law of its kind used to define microplastics within a state, which later led to the adoption of one of the first standardized methods used by a governmental agency to test for microplastics in drinking water.² Other actions taken by the US-EPA came in the form of including nanoscale particles as being a substance that is regulated as a “chemical substance” under the Toxic Substances Control Act (TCSA). This act identifies manufactures of and regulates the use of nanoparticles in industry by requiring heath studies, chemical identity, exposure and release data to accompany the manufacture and use of these products as a method of determining any regulatory actions required by EPA under this act.
What can the public do to help eliminate microplastics from entering the environment?
As members of the public, steps can be taken to reduce plastics from entering the environment by properly disposing of plastics, recycling of plastics and limiting regular uses of plastic products such as by using re-usable fabric shopping bags as opposed to using plastic ones when shopping for groceries. Try using less single use plastics eg, baggies or plastics wraps, or switch from plastic straws to paper or even by using a washable cup or tumbler for water instead of buying water in plastic bottles. To find out more interesting ways in which to reduce your use of products that contribute to the presence of microplastics, visit www.perchenergy.com
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¹ Effects of Microplastics on Fish and Human Health; S. Byuhan, 2022
² www.Californiawaterviews.com