Introduction
We are so absorbed with climate change these days that we haven’t appropriately sounded the alarm about the next biggest threat to the environment: plastics. Plastics and their smaller relatives, microplastics and nanoplastics, are ubiquitous in the environment and wreaking havoc. They are affecting every ecosystem on the planet, and the effects are magnified up the food chain. Our next major battle needs to be to reduce the terrible consequences of plastic pollution.
What Are Microplastics and Nanoplastics?
Microplastics are small particles of plastic, smaller than five millimeters. They are often invisible to the naked eye. Nanoplastics are less than 1 micrometer. For much of this article I will refer to microplastics, but nanoplastics are even more insidious.
Primary sources of microplastics include:
- Plastic pellets (nurdles) used in manufacturing to make plastics
- Microbeads formerly used in cosmetics
- Industrial abrasives
Secondary sources of microplastics include:
- Broken-down plastic bottles
- Food packaging
- Fishing gear
- Synthetic fibers
- Tires
Basically anything that is plastic can break down into microplastics.
Where Do Microplastics Come From?
Household Sources
- Washing synthetic clothing
- Plastic cutting boards
- Food containers
- Disposable packaging
Transportation
- Tire wear
- Road markings
- Vehicle components
Industry
- Plastic manufacturing
- Construction materials
- Paints
- Shipping
Agriculture
- Plastic mulch
- Irrigation tubing
- Fertilizer contamination
How Microplastics Spread Through the Environment
Just about anything we put into the environment will eventually end up in the oceans. Microplastics are no different.
It may start from a plastic bag carelessly allowed to blow away in the wind. It gets caught on a bush and sits there, partially on the ground, partially waving in the breeze, unnoticed for months, slowly scraping the branches as the wind blows.
Little particles of plastic come off onto the ground beneath the bush. A rain storm comes, and some of the particles are washed downhill into a nearby stream. From there, they flow easily downstream for miles. Some of them make it all the way to the ocean.
Others are captured along the way by, say a fish, which eats them thinking they are plankton. This, unfortunately, happens often because there are a lot of microplastics in the stream. The fish can’t expel them all, so they accumulate in its gut.
A bird catches the fish and has a delicious snack. But now the bird has the microplastics inside its gut. It eats more fish, and more microplastics, and soon its gut is full, but it has no nutrients. It dies of starvation with a gut full of plastic.
Back to the plastic in the bush. When the rain storm hits, not all the microplastics flow into the stream. Some go straight down through the soil to the aquifer, and into the groundwater. Lots of people have wells to get their drinking water. Now they are drinking microplastics.
Every person on this planet is thought to have microplastics in every organ of their body. We don’t know what the long term consequences are, but they can’t be good.
These were just two of the ways that microplastics can enter and spread in the environment. There are millions more. Microplastics have been found in every environment on the planet, from agricultural fields, parks, gardens, and forests to Arctic and Antarctic glaciers and the tops of mountains. We can’t get away from them.
Effects on Aquatic Ecosystems
I touched on it above, but fish often mistake microplastics for food. They can cause digestive blockages and reduced growth.
Shellfish are also affected. They cannot filter feed properly with microplastics blocking them.
Coral reefs, already in a dire situation due to climate change, are also under attack from microplastics. They reduce growth and cause disease and bleaching.
Even plankton are affected by microplastics. They are the base of the food chain, and if they are affected, so is everything above them.
Effects on Wildlife
Birds can mistake plastic for food, or they can eat things that already have plastic in them. The birds can’t digest the plastic, so it stays lodged in their intestines. They aren’t able to digest normal foods, so they die of starvation, even when their stomachs are full (of plastic). I’ve seen pictures where bird carcasses are decomposing, and there’s a big pile of plastic where their stomach once was.
Mammals aren’t immune from the effects of microplastics, either. They can eat the plastics directly, or they eat things that have plastics inside them. Small mammals can be affected much like birds, and larger mammals don’t seem to die quickly, but microplastics accumulate in their tissues. It can’t be good for them (or us).
Indeed, all animals are susceptible to the ill effects of microplastics, including reptiles, amphibians, insects, and anything else.
Effects on Plants and Soil
I illustrated earlier how microplastics can infiltrate the soil and seep into the groundwater. But as this is happening, some of the plastics will be retained in the soil. This causes changes in the soil structure affecting water retention and nutrient cycling. Also, dangerous pollutants can attach themselves to microplastic particles, poisoning the soil.
This, in turn, affects microorganisms in the soil, as well as larger organisms like earthworms. These changes in the soil can affect how plants grow. Microplastics can infiltrate plant tissues, and from there, they affect the entire food chain.
Microplastics in the Food Chain
Once the microplastics enter the food chain, they start to bioaccumulate and biomagnify. Bioaccumulation is when more and more particles accumulate in one individual. In other words, they enter the body but do not leave, and they get concentrated in the body.
Biomagnification is when they get even more concentrated the higher up the food chain you go. For instance, a fish may have a fairly low concentration of microplastics in its tissues, but then it’s eaten by a small mammal, and because that small mammal is eating a lot of fish, as well as getting it from the water and plants, it gets more concentrated in its body. Then a larger mammal eats the small mammal, and it gets even more concentrated. And so on up the chain.
Humans are generally at the top of the food chain, so this does not bode well for us!
Climate Change Connections
Microplastics are linked to climate change, as well. Plastic production is a major source of carbon dioxide, which is a major greenhouse gas emitter. Plastic degradation causes further greenhouse gas emissions, and as mentioned before, it can alter soil structure, which can lead to less carbon retention in the soil and more in the air.
Economic Impacts
Degradation of the environment has impacts on the economy, too. Fisheries suffer when the fish are smaller. Tourism may suffer as coral reefs disappear. Agriculture suffers as crops dwindle due to lower nutrient levels. Water treatment costs increase as measures to limit microplastics are introduced. And cleanup expenses skyrocket as we try to remove these unwanted particles from the environments around us. There is a lot of work to be done.
What Scientists Are Still Learning
We still don’t know what the long term effects of microplastics in our bodies are. We do know that microplastics are in every organ of our bodies.
It’s very hard to research what the effects are since microplastics are so ubiquitous. We have no control groups for experiments, and it’s hard to tease out what is caused by microplastics.
New research is published weekly about the effects of microplastics on the environment. Mainly, we are finding that microplastics, and their smaller relatives nanoplastics, are even more common than was thought.
Also, they can have communities of microorganisms living on them. Scientists are studying whether these microorganisms are spreading invasive species, transporting pathogens, affecting aquatic ecosystems, or changing how plastics break down.
Scientists have also found that some bacteria, fungi, and enzymes can break down plastics in laboratories. They are studying whether these could be used to clean contaminated soils, improve recycling processes, and reduce plastic waste in general. These inquiries have a long way to go before they can be tested in the wild.
What Individuals Can Do
- Reduce single-use plastics
- Choose natural fibers
- Use reusable products
- Dispose of plastic properly
- Support recycling
- Participate in cleanups
- Reduce tire wear (Drive smoothly and maintain proper tire pressure.)
- Write to your legislators
- Write to businesses
- Vote
- Vote with your dollars
- Spread the word about the dangers of plastics
What Governments and Business Can Do
- Product design
- Packaging design
- Improve recycling
- Better waste management
- Plastic reduction policies
- Innovation in materials
Ultimately, businesses need to reduce the amount of plastics they produce in order to make much of a difference in the amount of plastics in the environment. Some of the plastics we use are necessary, but the majority are just more convenient and not worth trading our wellbeing and our children’s wellbeing for.
Conclusion
Microplastics are one of the most serious threats to the environment that we have seen so far. They affect every plant and animal and invade every nook and cranny on the planet. We can’t wait until we have solved climate change to address this problem. We must address it immediately.
0 comments