While marine plastic pollution has been studied for decades, the extent and effects of plastic pollution elsewhere is only just beginning to be explored. In the past few years, scientists have found microplastics in our soil, tap water, bottled water, beer and even in the air we breathe. And there’s growing concern about the potential health risks they pose to humans. Because research on microplastics on land and in freshwater is still in its infancy, there are no accurate figures on the extent of the problem, but some studies have suggested there are more microplastics on land than there are in our oceans. Globally, more than 330 million metric tons of plastics is produced each year, leaving potential sources of microplastic pollution all around us.
Research has found that fertilizers are one of the leading contributors to plastic pollution. In many countries, sewage sludge, the semi-solid by-product of sewage water treatment, is used to fertilize the agricultural fields. Though this may be seen as a resourceful way to reuse and preserve our water supply, it makes the food we consume hazardous to our health. The sludge very often contains microplastics in the form of microbeads found in cosmetics that have been washed down the sink and clothing fibers that get flushed into sewage systems after synthetic clothes are machine washed.
Exactly what happens to these plastics once they’re in the environment is largely unknown. “It’s crucially important that we get a hold on what’s happening on the land,” said professor Anne Marie Mahon of the Galway-Mayo Institute of Technology in Dublin. She studies microplastic pollution and has found it in Irish tap water and well water. Other research recently found microplastics in bottled water around the world. “It’s vital we know if they travel over land,” she said. “Do they stay in the top of the soil? Do they become integrated vertically into the soil column, in which case there could be a risk to groundwater?
“Even if they stay on the surface, they could be washed into streams when it rains. And even if they don’t get washed into streams, there’s still the potential for environmental impact, and then there’s the whole terrestrial food chain.”
Though there’s little known about the effect on plants or on the wider food chain, studies have shown that earthworms exposed to microplastics in soil have increased gut inflammation, slower growth and higher mortality.
Professor Frank Kelly, director of the Environmental Research Group at King’s College London who is researching the presence of microplastics in the air says they are definitely present, what we are unsure of is at what degree. They are also often found in indoor air, according to this report, so we can’t avoid plastic contaminated air by staying at home. “Inside modern homes there’s lots of potential sources of plastic,” Kelly said. “Potentially from erosion of synthetic carpets but also fibers could be released by putting on and taking off our clothes.” One source of airborne microplastics is the same fertilizers that contaminate the ground; as these fertilizers dry out, some of the plastics may get carried away by wind action.
Though scientists aren’t sure how these plastics affect humans, they believe there is a potential health risk. One risk stems from the fact that microplastics passing through wastewater plants can pick up harmful bacteria, which they can carry with them. If we ingest the plastics, we may ingest the bacteria. Another is that plastics have a number of chemicals added at the manufacturing stage, and it’s possible that these are released in the body. According to Kelly, “In sufficient concentrations the chemicals can injure and kill cells,” these sells may be replaced successfully, or they may not. Kelly says they could cause “damage to protein and DNA and things like that.” And while microplastics are too big to be absorbed by our cells, if they become broken down into fragments in the nanometer size range, it’s possible they could be absorbed in our circulatory system or pass into our organs, Mahon said. But whether that’s actually happening is another unknown. It’s one reason why scientists and environmental groups are saying there’s an urgent need for more research.
And with global plastic production expected to triple by 2050, along with the fact that some plastics can take hundreds of years to biodegrade, microplastic pollution is a problem that isn’t going away.
Source: CNN