Microplastics: A Macro Threat to the Food Planet
Images of turtles entangled in plastic often hit the headlines. When it doesn’t directly kill marine life, plastic debris breaks down into tiny pieces called microplastics. They’re on seafloors and in the groundwater. They’ve even found their way to some of the Earth's most remote places, such as Antarctica. A recent study also discovered plastic fragments in the air we breathe. Microplastics are a fast-spreading plague.
While we use plastics in nearly all aspects of life, our global appetite for this petroleum byproduct is notably fueled by the way we produce, distribute, consume, and dispose of food; food and drink packaging alone accounts for 16% of all plastics produced. Microplastics have infested the entire food chain, polluting land, water and atmosphere; this could potentially have disastrous environmental- and public health consequences.
Land contamination –Microplastics flushed into the soil
The agricultural sector contributes greatly to the problem, using 6.5 million metric tons of plastics annually. Mulching – covering soil with plastic film – conserves water and controls temperatures, it accelerates growth and prolongs the seasons for certain vegetables, but it causes widespread soil and crop contamination. Paradoxically, despite the existence of plastic-free alternatives such as wood chips, leaves, grass trimmings or straw – which have the added benefit of enhancing soil quality – mulching is still favored by organic farmers as it increases productivity without the use of prohibited fertilizers and pesticides.
Beyond plastic mulch, tunnels, greenhouses and seed coatings – yes, as crazy as it sounds, seeds are coated in plastic – sewage sludge is by far the largest source of microplastics on farmlands. Whether poured directly on soils or first processed as biosolids, this fertilizer resulting from sewage treatments is predominantly used in industrialized countries and accounts for 92% of microplastics contamination on farms. The impact of such large-scale use remains unknown. Still, a 2019 Kansas State University lab experiment showed that wheat grown with microplastics contained 1.5 times more cadmium, one of the most toxic components in sewage sludge. The experiment also found drainage problems in plastic-contaminated soils.
Water contamination –Plastics dumped into the ocean
Although microplastics "only" account for 8% of the total mass of debris found in the infamous Great Pacific Garbage Patch, they represent 94% of floating fragments, the very particles that take off and travel in the atmosphere when powered by waves and wind. As if that wasn’t bad enough, a study from Australia's national science agency, CSIRO, estimates that there are 35 times more marine habitat-threatening microplastics buried in the seabed than floating on the surface of oceans. What's more, fishing nets make up the vast majority of larger debris in the oceans, some of this plastic eventually enters our food chain, from the plankton that krill eat, to the salmon fillet on your plate. Microplastics have even found their way into groundwater.
Air contamination –Microplastics dispersed into the atmosphere
We force-feed our lands and waters a colossal quantity of plastic which is spat back out into the atmosphere. Once in the air, microplastics can travel for up to six and a half days, accumulating organic pollutants, exposing the ecosystems to additional air pollution and posing risks of respiratory diseases, according to a study conducted by researchers at Utah State University and Cornell University.
Not only are we breathing plastic particles, but we’re also eating a credit card-sized amount of microplastics each week. This can affect our immune system and facilitate the transmission of toxic chemicals and pathogens. We ingest microplastics through seafood and related chemicals through direct transfers from food packages. Bisphenol A is a carcinogenic and endocrine-disrupting substance found in food and beverage packaging, e.g., water bottles and soda cans. This synthetic compound is banned from use in baby bottles in most industrialized countries, though it’s still allowed in nearly all Low-Income Countries.
Despite scientific findings and alarming evidence, plastic production continues to rise and is projected to quadruple by 2050. By then, we will have generated 26 billion metric tons of plastic waste, further contaminating the planet.