Plastics: Physical effects

The crisis of plastics in our oceans has received an enormous amount of attention over the past couple of years. This has led to efforts to reduce the use of plastic materials such as bans on plastic straws. To understand why plastic in our oceans is such a significant threat, we must understand the physical forms that plastic takes in the environment. Macro plastics are often the products that we use. These are the single use carrier bags, bottles, and food containers from grocery stores. The packaging that goods are shipped in and the plastic products that we use in our daily lives. Macroplastics also make up abandoned fishing equipment like netting that is disposed of in the ocean.

Take a look around your house and note all the plastic products that you have. When macro plastics enter the environment, natural processes including physical mixing and sun exposure act to weather these products and break them up into smaller pieces. Particles less than 5mm are classified as microplastics. But not all microplastics are a result of the breakdown of larger plastics. Microplastics are intentionally added to many products including face scrubs, beauty products, and even glitter used in crafts. Microplastics can also take the form of fibres which are generated from the synthetic fabrics that our close are made from and are released when we wash them.

There is growing concern amongst scientists about a new class of plastic pollution even smaller than microplastics, called nanoplastics. These are largely formed by the breakdown of microplastics and are 10-1000 times smaller than the smallest microplastic. If you live in a place that is far from an ocean, you may think this issue does not apply to you. However, the improper disposal of plastic waste inland often ends up in rivers and streams which eventually leads to the ocean. The longer the pathway to the ocean, the more opportunity for these macroplastics to breakdown into micro and nanoplastic particles. We are just starting to get an understanding of the environmental impact of plastic pollution. The risk to wildlife for macroplastics is most obvious.

Marine life including whales, seals, and sea turtles can get tied up in large pieces of plastic waste. Sea birds mistakenly eat plastic waste, filling themselves up, but missing the nutritional benefits needed for their survival. The impacts of microplastics are less obvious. However, smaller order organisms consume them, and similarly to macroplastics, do not gain the nutrition necessary to survive. Microfibers can get caught in organisms digestive systems causing internal stress. These impacts are then passed up the foodchain. We are just beginning to study the impacts of nanoplastics. But with the ability to penetrate tissues like gills and lungs, nanoplastics may represent an even greater ecological risk.