Organic fertilizers from biowaste fermentation act as a vehicle for microplastic particles to enter the terrestrial environment, with the amount of microplastic particles differing based on pre-treatment methods and plant type, a new study shows.

Recycling of organic waste through composting or fermentation, followed by application of the resulting fertilizer products to agricultural land, is considered environmentally friendly, but the results of this study challenge that common perception and highlight an overlooked source of pollution.

Due to their small size, microplastic particles (MPPs) - mainly fragments, fibers and spheres of plastics, all smaller than five millimeters - presumably enter the food web, and may even end up in human food.

Considerable attention has thus been given to MPPs, but largely to those discovered in the ocean. Only more recently have researchers expanded their study to include microplastic pollution in terrestrial environments.

To better understand MPP production and initial entry into terrestrial ecosystems, Nicolas Weithmann and colleagues screened different organic fertilizers produced at recycled biowaste plants for MPPs greater than one millimeter in size.

Their screens focused on outputs of biowaste composting plants (which processed biowaste from households) and on outputs of biowaste digester plants (which create biogas from manure). As a reference, they also looked at MPP loads from agricultural energy crop digestion plants, which process only energy crops like corn, and no biowaste.

All fertilizer samples converting biowaste contained MPPs, they report - usually between two and five mm in size - while none of the samples from the agricultural energy crop digester plants contained significant amounts of the tiny plastics. The amount of MPPs from biowaste treatment differed based on pretreatment and plant type; the MPP load produced from biowaste digester plants, for example, was greatest.

In particular, the biowaste digester plant directly supplied by waste from commerce contained the highest numbers of MPPs (895 MPPs per kilogram of dry weight). Based on their findings, further study into the possible consequences and impacts of MPP contamination from these types of biowaste fertilizers is necessary before any risk can be assumed, Weithmann et al. say.

Research paper

Related Links
American Association for the Advancement of Science
Farming Today - Suppliers and Technology

Tweet

Thanks for being here; We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor $5 Billed Once credit card or paypal		SpaceDaily Monthly Supporter $5 Billed Monthly paypal only

Fixing soybean's need for nitrogen
Washington DC (SPX) Apr 11, 2018
Soybean is rich in protein, which is great for the humans and animals eating it. But this high protein content comes at a cost. To make protein, soybean plants need a lot of nitrogen. The plants get some of the nitrogen they need by working with specialized bacteria in the soil. These bacteria live in root nodules. They pull nitrogen from the atmosphere and convert it to a form the plants can use. But this process-biological nitrogen fixation-may not provide all the nitrogen soybean crops ne ... read more