Microplastics, already a problematic presence in water, seafood, and other things we consume, are showing up in other parts of the food chain, including fruits and vegetables. Let our leaders know it’s time to stand up to industrial interests and reduce our exposure to harmful synthetic pollutants.
We’ve known for years that microplastics have invaded our oceans, rivers and drinking water. It’s a challenge to take water samples anywhere, even Earth’s most remote places, without finding these small polymers. But scientists now believe microplastics may be just as widespread on farmland, where they can end up in food grown and raised there.
Microplastics – and their tiny counterparts, nanoplastics – are either manufactured small for use in commercial and industrial products, or they’re the remains of synthetic textiles or other plastics broken down by sunlight, suds or even scissors. On farms, they can come from many sources, including plastic mulching and degraded water pipes, but recycled sewage sludge is a huge factor. This largely organic material left over from the water treatment process is applied as fertilizer all over the world because it’s widely available, inexpensive and rich in nitrogen and phosphates. We now know it’s also rich in microplastics – about one percent of sludge is composed of plastic particles too small to filter out before heading to the farm. These pieces settle into soil, where moisture-seeking plants draw them up into their roots.
One recent survey of produce in Sicily found apples and carrots were most likely to contain microplastics. Because most microplastics remain in the plant’s root systems, we’re more likely to ingest them from eating root vegetables – radishes and turnips, for example – than such leafy produce as lettuce and kale. Unlike surface pesticides, which we can mitigate by rinsing produce before eating it, microplastics become part of the plants themselves. Of course, as livestock graze on polluted land or eat contaminated grains, that adds to the microplastics in our meat and milk.
We get a lot of microplastics in our diets already – they’re pervasive in fish, especially oysters, clams and mussels, found in high concentrations in salt, beer, rice and honey, and microscopic particles even flake and fall into foods and beverages from plastic packaging. American tap water has the world’s highest rate of plastic contamination, with one study finding fibers in 94 percent of its samples. If you’ve ever used a body scrub or toothpaste with abrasive plastic microbeads, you’ve put microplastics directly on your skin and in your mouth. .
Australian researchers found that we ingest, on average, 5 grams of plastic – the weight of a credit card – every week. We excrete about 90 percent of it, but that still leaves a lot behind.
The long-term health effects of this exposure aren’t fully understood – the small sizes, numerous varieties and widespread presence makes it hard to study microplastics – but there’s plenty of evidence that ingredients in plastics are bad for us, including increasing our risk of cancer, heart disease and inflammation. We know some ingredients in plastics disrupt the endocrine system and reproductive hormones, while others affect fetal development. Researchers have found microplastics in placentas and breast milk, which means babies consume this material directly in the womb and during their first months of life.
There are also hazards specific to microplastics and nanoplastics. Sharp-edged remains of deteriorated plastic can sometimes puncture our cell walls, killing the cell itself. Some particles are small enough to cross the blood-brain barrier and circulate throughout our bodies. Toxic substances and bacteria can attach themselves to – or be absorbed by – tiny polymers, hitching a ride directly into our organs and systems. These particles are also easy to inhale – clothes dryers tend to loosen tiny fibers from synthetic materials and make them airborne. One researcher examining lung tissue taken from thirteen people awaiting chest surgeries found a total of 39 plastic particles in eleven of those patients.
Scientists say it may be another decade or more before we fully understand how serious this problem is and, in the meantime, microplastics concentrations in the water, soil and air will only grow. Switzerland and The Netherlands have taken limited action to stop sludge use on their own farmland, but the Netherlands now simply exports its sludge fertilizer to other countries. In the United States, lawmakers and federal regulators have been hesitant to act, yielding to aggressive pressure from major oil and chemical companies. It wasn’t until 2015 that the United States even approved a ban on cosmetic microbeads, arguably the lowest-hanging fruit of the microplastics problem. One recent Congressional bill to merely study the problem and potential solutions went nowhere. To show the government’s mindset, rather than looking for ways to reduce plastic waste, it recently funded research to figure out how to turn it into food.
We can all play a part by replacing plastic bags with reusable cloth totes, avoiding plastic straws, and switching to bamboo-based utensils. Air purifiers and HVAC filters may be able to reduce microplastics in our homes, and we can buy fewer synthetic clothes and carpeting.
