Microplastics and Their Effect on Aquatic Animals
Plastics have become an everyday part of society with products ranging from tires and hospital IV bags to cellphones and computers to fleece clothing and food containers. Mass production of plastic began in the 1940s and today over 300 million tons of plastic are produced worldwide each year. Plastic has made life for many people easier and more convenient, however it has also created an enormous pollution problem.
Is it estimated that it takes many plastic products hundreds of years to degrade. In the short term, weathering and sun exposure cause these items break down into smaller particles such as micro and nanoplastics. Microplastics are tiny fragments of plastic debris that are usually smaller than 5 millimeters in length. Microplastics not only result from larger plastic debris that is degrading but can also be intentionally manufactured to be small. These plastics, called microbeads, can be found in toothpaste, face wash, and other health and beauty products.
Microplastics can enter aquatic habitats in several ways, through littering, water run-off, and poor solid waste management. Some of these plastic particles are even small enough to bypass filtration systems and have been found to enter the water supply when households do their laundry. Fleece, for example, is usually made from recycled plastic bottles and petroleum. Once in the environment, these microplastics can harm a variety of wildlife including birds, fish, turtles and marine mammals. According to one report published in 2009 by David Barnes, a lead author and researcher for the British Antarctic Survey, over 180 species of animals have been found to have ingested plastic. In terms of aquatic animals, scientists have found microplastics in 114 species, both freshwater and marine, wild caught and farmed.
There are several ways microplastics cause harm to aquatic animals. The most obvious is that they can block an animal’s digestive system, which in turn reduces their consumption of nourishment, affecting growth and reproduction. This can be fatal for some animals because they eventually starve. Additionally, the chemical composition of plastics is detrimental to aquatic life. They are not only petroleum based, but they also contain harmful chemicals that pose risks to marine ecosystems and biodiversity. Petrochemicals and their byproducts are known to cause a variety of health issues, including cancer, for living creatures, both animals and humans. Not all of the chemical additives in plastic have been tested for toxicity, however research has shown that the ones that have been tested are known endocrine disrupters, which negatively affect the endocrine system in humans and animals by creating adverse developmental, reproductive (e.g. lower fertility), neurological, and immune effects (e.g. increased risk of cancer) Furthermore, a Global Microplastics Initiative found that microplastics are capable of absorbing other toxic chemicals that they come into contact with while in the water, such as BPA, DDT, phthalates, and heavy metals. Neurological damage is also possible after the animals have ingested the microplastics as the toxic chemicals have the ability to cross the protective border that separates the blood from the brain. This can then result in structural and functional damage to the brain. Additionally, a study by Professor Chelsea Rochman from the University of Toronto in 2016 has shown that fish that ingest chemically treated plastic have resulting liver damage. This liver damage reduces the animal’s ability to metabolize drugs, pesticides, and other pollutants. Not only does plastic negatively impact the animal that ingests it but, then some of these damaging substances are transferred to other animals through the food chain.
Despite the fact that plastic production continues to increase, there are ways that this devastating problem can be addressed. As individual consumers we can take multiple actions such as opting for reusable water bottles and coffee cups, reduce use of beauty products that contain microbeads, and supporting ballot initiatives that are aimed at banning them locally. One of the easiest actions that can be taken is to pick up litter when you see it. On a larger policy level, nations can ban specific types and uses of plastic, such as plastic bags at retail establishments. Chemical companies should continue to create plastics that are plant based and made to biodegrade. Lastly, government systems can invest in infrastructure that will both help to recycle plastics and also properly dispose of solid waste.
Sources: National Center for Biotechnology Information, National Geographic, National Ocean Service, One Green Planet, Scientific American