Microplastics are not just in us, they are also in wildlife

Microplastics are accumulating in just about every ecosystem on Earth, from the depths of the ocean in the Mariana Trench, to the snowy top of Mount Everest, to everywhere in between. All of these microplastics are having harmful impacts on wildlife.

Plastic pellets are dangerous for wildlife

Microplastic is how plastic both begins and ends. The first recognizable plastic following conversion from oil or gas is something known as a plastic pellet. Under 5 mm in size, these are rarely seen by most people, but are mass produced to be melted and molded into everyday plastic products– everything from single-use plastic straws, to kid’s party favors, to car bumpers. It is estimated that 10 trillion plastic pellets enter our oceans every year.

While broken down shards of plastic bottles are emblematic of microplastics, the raw, industrial pellets synonymous with the global plastic supply chain are often overlooked. With global plastic production estimated to nearly triple by 2060, the scale of the impact of plastic pellets on ecosystems and wildlife is immense, and growing.

Seabirds often mistake plastic pellets for food

Shorebirds and seabirds are particularly vulnerable to eating industrial microplastics, due to their accumulation on beaches and floating within our oceans. They (along with fish, turtles, and crustaceans) can confuse plastic pellets for food, as pellets resemble organic matter, such as tadpoles, fish and salamander eggs. If they mistake too many pellets for food, they can starve, as the plastic blocks their digestive tracts. For example, polyethylene pellets can remain in the digestive tract of birds between 2-15 months, depending on the type of polyethylene plastic and the type of digestive tract of the bird. 

Fulmars, a type of seabird, are helping us to understand the extent of plastic animals are consuming in the oceans. They eat while at sea, which makes them vulnerable to feeding upon floating plastic. Rather than regurgitating the hard bits of prey (or plastic), like many other birds do, fulmars accumulate hard bits in their stomach, and slowly grind those bits down until they are a size which can pass through the rest of the digestive system. In 2022, Wageningen University collected the dead bodies of 66 Northern Fulmars and found that 94% had plastic in their stomachs, including plastic pellets, with an average of 19 pieces of microplastic per bird. 

Fish and marine mammals are also negatively impacted by plastic pellets

Fish not only eat plastic, but they consume organisms which have eaten plastic, which gets passed along to them, in a process known as trophic transfer. Studies have shown that when fish consume microplastic it can decrease their numbers and strength by causing many internal issues, such as inflammation, immunotoxicity, genotoxicity, and DNA damage. It can even change their behavioral patterns, swimming and feeding habits. On a more basic level, exposure to even a small amount of plastic pellets can cause stress for sea urchins, which can trigger other issues, such as less successful embryos. 

Microplastics have been found in all seven species of sea turtles. Juvenile sea turtles are particularly vulnerable to consuming plastic, because they drift and feed on the ocean’s surface, where seaweed and other ocean debris, including plastic, accumulates. A turtle was found on a beach in Brazil that weighed about 13 pounds, but had over 3,000 pieces of plastic within its large intestines. Another study found when there was an acute spill of plastic pellets in the Gulf of Mexico the amount of pellets found in the stomachs of turtles in the area increased. 

Plastic pellets expose animals to toxic chemicals

Pellets contain chemicals, such as plasticizers, flame retardants, UV stabilizers, etc. and they act as sponges. They both leach toxic additives and absorb toxic chemicals, including DDT, PCBs, and mercury. Studies show PCBs can decrease animal fertility, cause cancer, and the effects of these endocrine-disrupting chemicals can be passed on to offspring, which indicates the chemicals are causing genetic changes. A study completed near one of the largest ports in South America, in Brazil, which also has plastic pellet pollution, found that isopods become more aggressive, specifically cannibalistic, when exposed to heightened levels of plastic pellets in water.

Leachates have been shown to affect hormonal systems in both vertebrates and invertebrates which subsequently can affect reproduction, oxidative stress levels, feeding behavior, physiology as well as metabolic and immune functions. A study of mussels, a keystone species, in France and Portugal found that microplastic leachates from plastic pellets affected respiration rates, meaning they filtered less algae, which affects oxygen rates in water and could potentially have knock-on effects on ecosystems. In short, leachates can weaken animals and contribute to biodiversity loss. 

The animals and ecosystems we love are suffering from our plastic pollution and they cannot repair the damage, but we can. Plastic pellet pollution is not something that is a given and we have to just accept. There is a bill in congress now that would help prevent it– the Plastic Pellet Free Waters Act would ban the discharge of plastic pellets from facilities that make, use, or transport plastic pellets. Urge your representatives to pass the Plastic Pellet Free Waters Act today.