Fashionable organic food may be contaminating consumers with microplastics due to microplastic-filled compost polluting organic farms, according to a study published Wednesday in Science Advances.
German scientists studying organic fertilizer found it contained huge volumes of plastic and observed that “because of their small size, MPPs (microplastic particles) may presumably also enter the food web and thus potentially end up in human food.”
The study comes at a time when “organic” is marketed as a synonym for “good” in everything from salmon to sweet potatoes, and at a time of growing concern about plastics fouling the planet’s oceans.
Until now, microplastic pollution on land has attracted little attention, but the study warns that a closer look is needed. The study warns there is no telling what happens when microplastics mix with agriculture.
“There they pose a risk that is not yet predictable, because the interaction of MPPs with tissue and cells is poorly understood. Investigation of the interaction is further complicated by the fact that MPPs are not single compounds but constitute mixtures of different plastic types, each often consisting of a blend of synthetic polymers, residual monomers, and chemical additives.”
The study warns that the compost used in organic farming might not be all that much better than “sewage sludge,” which the Germans now incinerate to keep it from polluting the landscape.
Organic fertilizer, on the other hand, is spread across the landscape, and in the process appears to be distributing microplastics on a massive scale.
2.2 Trillion pieces
In Germany alone, the researchers from University of Bayreuth calculated organic fertilizers could be annually pumping into the environment somewhere between 35 billion and 2.2 trillion pieces of microplastic bigger than 1 mm in size. They could not calculate the volume below that size.
Most of this little-noticed plastic, according to the research team led by Nicolas Weithmann at Bayreuth, comes from polypropylene, polyethylene, polyvinyl chloride (PVC), polyurethane, terephthalate (PET), and polystyrene.
Alaskans are well familiar with polypro. It’s the stuff used to make long johns and other undergarments now favored for winter wear for their ability to insulate without absorbing moisture.
Polyethylene, meanwhile, is the world’s most common plastic. It is regularly used for grocery bags and newspaper wrappers. PVC is used in everything from pipes for plumbing to credit cards. Polyurethane is used to make insulation and the foam that provides cushioning for chairs and couches.
PET is used to form the plastic water and soda bottles seen everywhere today and for packaging other food and merchandise. And polystyrene is used to make parts for appliances, electronic equipment and automobile parts, not to mention toys, disposable eating utensils, CD boxes, cups, carry-out food boxes, packaging and insulation. Big blocks of polystyrene sometimes wash up on Alaska beaches where they take years to decay.
The ocean decay of plastics into microplastics and even smaller, invisible microbeads has been an issue of growing concern among scientists.
“Microplastic contamination of the oceans is one of the world’s most pressing environmental concerns,” a group of British scientists reported in Nature Geoscience just last month.
When examining rivers in northwest England, they found “multiple urban contamination hotspots with a maximum microplastic concentration of approximately 517,000 particles per square meter.”
The good news was floods flushed most of it out sea. The bad news was floods flushed most of it out to sea.
Plastic stuffed salmon
“Many species of marine fish (more than 50) ingest plastic debris. Ingested plastic has a variety of lethal and sublethal impacts and can be a route for bioaccumulation of toxic compounds throughout the food web,” scientists from the University of California Davis reported in Proceedings of the Royal Society Biological Sciences in August of last year.
The plastics have shown up in salmon from Alaska and elsewhere which is not good news for an Alaska salmon industry trying to promote its fish as healthier than farmed salmon.
“Unfortunately, you as a consumer would have no idea if the salmon you buy in the store has consumed plastic,” EcoWatch was warning as early as 2015. “But chances are, it has, either by mistaking it for food and eating it directly, or by feeding on zooplankton that have eaten the plastic.”
Emerging, on-land salmon farms have already latched onto the value of selling uncontaminated salmon in a marketplace where commercial salmon fishermen years ago started a fight with salmon farmers over which salmon is healthier: those caught in the wild or those raised in coastal pens.
A growing band of dry-land salmon farmers are making the argument the answer is neither, but instead “locally grown” fish raised in carefully monitored and filtered water.
“Our water is free from heavy metals and other contaminants, so our fish and produce are free of them too,” proclaims Superior Fresh, a joint salmon farm and greenhouse operation in Wisconsin.
The Superior pitch echoes that long used by organic farming advocates.
NaturesPath.com offers “11 Reasons Why Organic Food is Better for You & the Planet.’‘ The first reason involves “taking a stance against the large chemical producing corporations that have polluted the world’s food and fields,” the website says.
But the new study indicates organic farmers could unknowingly be among those polluting “the world’s foods and fields.” Scientists have for some time been questioning whether organic foods are really any healthier and the latest study only adds fuel to the debate.
Weithmann and his groups at the Process Biotechnology and Centre for Energy Technology in their study paint a picture of what might good intentions gone badly awry.
In Germany, huge volumes of organic waste from homes and industry are composted or first used for biogas energy production and then composted. Recycling organic material in this way is, “in principle, an environmentally sound practice to return nutrients, trace elements, and humus to the soil,” the study said.
“However, most household and municipal biowaste is contaminated by plastic material. Sieving and sifting procedures can significantly reduce, but never completely remove, these contaminants. Moreover, most countries allow a certain amount of foreign matter such as plastics in fertilizers; for example, Germany, which has one of the strictest regulations on fertilizer quality worldwide, allows up to” 0.1 percent of the fertilizer weight to be plastic particles larger than 2 mm.
Plastic particles smaller than 2 mm are not considered in calculating the amount of plastic in the fertilizer. There are no national standards for plastics in organic fertilizers in the U.S., but some states do regulate the amount of “inert material” – primarily glass and plastic – allowed in organic fertilizer.
“Compost will not contain greater than 3 percent inert materials that are greater than or equal to 4 millimeters,” a Minnesota statutes specifies. There is no limit on materials smaller than 4 millimeters, or a little more than an eight of an inch. The regulation appears aimed more at the cosmetic appearance of organic fertilizer than worries about microplastic pollution, which the German study suggests could be massive.
“In Germany alone, which has one of the strictest regulations on fertilizer quality worldwide, more than 12 million metric tons of biowaste were either composted or passed through municipal biogas plants in 2013,” the scientists wrote. “This quantity of biowaste translates into more than 5 million metric tons of compost from these plants, most of which is used in traditional agriculture and gardening.
By sampling small amounts of that compost for microplastics and then extrapolating for the 5 million tons of fertilizer, the scientists arrived at that estimate of 35 billion to 2.2 trillion pieces of microplastic larger than 1 mm and an unknown number of smaller particles.
The study then offered this comparison to other organic waste:
“Sewage sludge is in the public opinion increasingly seen as problematic waste inappropriate for redistribution into the environment, probably not least because of the contamination with heavy metals, residual pharmaceuticals, and also artificial fibers. The latter was detectable in agricultural soils up to 15 years after application of sewage sludge.”
Organic fertilizer, the study added, might not be much better because “MPPs from biowaste processing plants inevitably enter the environment. Because Germany has one of the strictest regulations on fertilizer quality worldwide, we here report only on the ‘best case scenario,’ whereas the MPP contamination in countries with less strict regulations may be even higher.”
The study called for a much closer examination of what happens to these plastics in nature. They could further break down in harmless ways or bioaccumulate as dangerous poisons in the food chain.
“At least one study has shown that (pristine) polyethylene particles mixed with litter and offered to earthworms for uptake led to higher mortality and a reduced growth rate,” the study said. If the worms that survive accumulate polyethylene pollutants, they could pass them along to the birds that eat worms and move the chemicals up the food chain.
“Further studies on the possible consequences and impacts of MPP contamination of fertilizers originating from biowaste treatment plants for soil quality and soil life forms are necessary before any risk assessment can be undertaken,” the scientists concluded.
It could turn out that eating small bits of plastic with every meal is harmless, or it could be that microplastic-coated organic lettuce or microplastic-filled Alaska salmon could be trying to do you in.
“Microplastic is actually very absorbent and picks up the chemicals it is floating in. So it’s not just the plastic a fish is eating, but all of the contaminants in that plastic as well,” EcoWatch warned. “That goes for us, too, if we eat a fish that’s eaten plastic particles.”
North Pacific Ocean fishes ingest 12,000 to 24,000 tons of plastic each year, according to The Center for Biological Diversity, which claims “that a quarter of fish at markets in California contained plastic in their guts, mostly in the form of plastic microfibers.”
The activist group contends that, among other chemicals, the plastics “release potentially toxic chemicals such as bisphenol A (BPA), which can then enter the food web. When fish and other marine species mistake the plastic items for food, they ingest the particles and pass toxic chemicals through the food chain and ultimately to our dinner plates.”
BPA is a chemical that leeches out of many water bottles, and its danger has been hotly debated in recent years.
“Many studies have been done on BPA in rodents and have shown that BPA is an endocrine disrupter and acts like the hormone estrogen,” writes Dana E. Christofferson at the Harvard Medical School. “Much of the controversy surrounds the determination of a safe dose of BPA for humans.”
As with all chemicals, the dangers relate directly to dosage. H2O can kill you if you drink enough of it. The problem with microplastics is that it is unclear as to exactly how they breakdown in the environment, and nobody has a clue as to what dosages of the derivative chemicals might begin to cause health problems in humans.
The German study raises a lot of question in a world filled with plastics. Look around you wherever you sitting at this moment, plastics are everywhere.