Microplastics in the Food Chain

Microplastics have been found at the top of mountains, at the bottom of the ocean, in the atmosphere, in tap and bottled water, in animals, and in the human body. Now researchers from the Chinese Academy of Sciences have discovered them in the plants we eat, meaning they have infiltrated the food chain far more than previously thought. 

The United Nations estimates our oceans contain 51 trillion microplastic particles, 500 times more than the stars in the Milky Way. The largest collection is the Great Pacific Garbage Patch in the northern Pacific Ocean, estimated to be 1.6 million square kilometers, 3 times the size of France. Similar collections exist in the southern Pacific Ocean, the Indian Ocean, and in the northern and southern Atlantic Ocean.

The majority of microplastic in the ocean comes from the degradation of plastic waste, which finds its way into the ocean due to improper recycling or carelessness. The waves, sun, and wind break down the plastic into smaller and smaller pieces over long periods of time. Microplastics also come from washing synthetic clothes, the breakdown of tires, and microplastics that have been added to products, such as microbeads, already these have already been banned for a few years (the US banned them in 2015).

Likewise, plastic dumped into landfills eventually breaks down and leeches into the ground water and soil.

Because of this, microplastics have been found just about everywhere, from the tops of mountains to the bottom of the ocean. Researchers have also found microplastics in human stool samples, with some estimating that we ingest about a credit card’s worth of plastic every week. The sources are our drinking water, both bottled and tap and of course the food we eat, although land based animals were thought to be less affected than sea life.

Some pieces of microplastic can be as small as 10 nanometres, which is invisible to the human eye. Such a small size allows them to be easily transported through water ways, ocean currents, and even through the jet stream. It also means they can be easily ingested by animals and humans and travel through the bloodstream, raising the alarm for what effect they might be having on the human body.

To make matters worse, Chinese researchers discovered that microplastic particles can penetrate the root system of wheat and lettuce plants. The authors of the study published in Nature Sustainability claim “Our results provide evidence in support of submicrometre- and micrometre-sized polystyrene and polymethylmethacrylate particles penetrating the stele of both species.”

Before this, it was assumed that only microplastics smaller than 50 nanometers could permeate plant roots, but the team from China found that microplastic particles 40 times larger could also get in. The researchers found that the site where new roots are growing provides a large enough opening to allow them inside. In fact, they believe even larger particles than they observed might be able to fit in these gaps. From the roots, the microplastic particles are free to travel through the plant into the edible portions, passing the microplastics up the food chain. 

This has caused some alarm, as now it seems that the entire food chain is affected. If plant life is infiltrated with microplastic particles, then so are the animals that eat the plants, as well as the animals that eat them. The health effect this has on humans is still unclear. Some scientists believe it can lead to inflammation, which is a major precursor for a myriad of other problems. Other scientists point to the fact that microplastics often have on them the industrial chemicals used to produce them, which contain heavy metals like cadmium, lead, and zinc. Once in the human body, heavy metals can wreak havoc in high concentrations.

While the effects on humans are still unclear, we need to stop dumping plastic into the oceans and landfills and remove the plastic that is already there. Many countries have already banned harmful products like plastic straws, plastic bags, microbeads, among others. The Ocean Cleanup believes they can remove half of the Great Pacific Garbage Patch within 5 years with their buoy system. Individuals can also be more conscientious about what products they use and how–or even if–they get recycled. To make a real difference, pressure your local and national government to increase recycling programs, ban harmful products, create awareness campaigns, etc. In fact, 91% of plastic doesn’t get recycled, mainly due to lack of recycling facilities.

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