A vast, heaving mat of plastic bobs on the waves in a bend of the Grijalva River within the Sudidero Canyon of Chiapas, Mexico. The one kilometre towering cliffs, diverse wildlife and thick rainforests of Mexico’s Grand Canyon are just as striking as the plastic bottles and other debris choking the waterway.
This is one of many examples where the waste of human societies harms the ecosystem and the animals within it.
At an individual level, plastic can be dangerous to wild animals through physical entrapment and ingestion. There are documented cases of plastic affecting more than 267 species of wild animals. We have all seen images of a wild animal entangled in plastic, whether it is a bear cub with its head stuck in a jar or turtles and birds in a six-pack plastic ring. These individual animals surely suffer greatly, making plastics a concern for animal welfare.
Wild animals are also harmed when they eat plastic. One poignant example is the impact of plastic consumption on seabirds, including gigantic albatrosses. Birds are attracted to the bright colours and eat these objects instead of food. Many die from starvation and blocked digestive tracts.
Fish and sea turtles suffer similar fates. Marine mammals including whales and dolphins also die from swallowing plastic.
Less striking but probably more serious is the issue of microplastics. Large pieces of plastic are broken down by physical means (imagine waves crashing plastic against a rocky shore) and ultraviolet light from the sun. This creates increasingly smaller pieces of plastic, eventually so small that they are not visible to the naked eye — microplastics are less than five micrometres in diameter. Microplastics are ingested by some of the smallest forms of sea life including oysters, mussels and zooplankton. Once microplastics are in these animals, larger animals that prey upon them may also get a dose.
As plastics work through the food chain, even the fish that people eat may contain microplastics.
There are also unseen consequences of plastic-associated toxins on the health of animals. Ingested plastics and also plastics battered by the elements and sun release a slew of toxins. Plastic associated toxins can accumulate in waterways, harming fish and other animals. These toxins can affect growth, reproductive and thyroid hormones. At a population level, these less visible impacts may be the most substantial.
It is easy to point a finger at the Mexican government and suggest that they do a better job of cleaning the river. But that would miss the upstream contribution to the problem — that people continue to use and toss single-use plastic containers and these end up choking rivers and eventually end up in the ocean.
In Canada, we are not often confronted with the images of our throw-away society, plastics included. The plastic in this Mexican National Park represented a proverbial drop in the bucket compared to the vast quantities accumulated in oceans and landfills.
The onus is on us as individuals to take steps to reduce plastic waste.
A few places to start include eliminating the use of disposable plastics like balloons, dishes, straws, bottles and bags.
Try reusable versions instead.
Recycle the plastic that you do use. Support businesses that limit their use of plastics and those that actively recycle.
While it is a privilege to visit one of the most beautiful natural areas in the world, it is also a reminder that we all need to do our part to reduce our impact on the environment and wild animals. That includes less plastic.
Dr. Jamie Rothenburger is a veterinarian who practices pathology and a PhD student at the Ontario Veterinary College. Twitter: @JRothenburger