Tag Archives: Plastics

The Mediterranean Sea is filled with plastics that come from elsewhere

Almost every country in the Mediterranean Sea has at least one Marine Protected Area (MPA) where over half of its macroplastics originated from another country, according to a new study. The findings highlight that plastic pollution is an international problem and we need international collaboration in order to tackle it, the researchers argue.

Image credit: Joan / Flickr.

Slowly but surely, plastic pollution has become one of the major environmental issues of our times, comparable to the climate crisis and overfishing. While much recent research focused on microplastics, this new effort looked at how macroplastics (plastic bits bigger than five millimeters) affect the marine ecosystem, as organisms ingest or become entangled in plastic litter — often with dramatic consequences. 

Plastic pieces (especially small ones) can travel very long distances and end far from their original sources. They come in unseen for multiple, often distant sources, threatening wildlife and their habitats in marine areas. Previous studies in the Arctic, the Pacific and the Atlantic have shown MPAs are very affected by plastic pollution. 

In the new study, a group of researchers focused on the Mediterranean Sea, one of the most polluted regions globally which also happens to be an important biodiversity hotspot. It’s shared by numerous countries in Europe, Africa, and Asia, which brings big differences in terms of governance, politics, and cultures — which makes it difficult to implement common regulations of marine ecosystems. 

About 229,000 tons of plastic leak every year into the Mediterranean Sea, according to a report by IUCN from 2020, equivalent to 500 shipping containers. Roughly speaking, it’s like dumping a container and a half of plastic straight into the sea. Egypt, Italy, and Turkey were identified as the countries with the highest plastic leakage rates into the Mediterranean, mainly because of mismanaged waste and large coastal cities.

“Our study shows that specific sites, important for the conservation of biodiversity, concentrate high amounts of plastics,” Dr Yannis Hatzonikolkis, lead author of the study, said in a statement. “Although marine protected areas are protected by restrictions from other threats as tourism, plastic acts like an ‘invisible’ enemy.” 

Plastics and the Mediterranean

The researchers carried out a three-year simulation (from 2016 to 2018) of the distribution of plastic particles in the Mediterranean Sea. They used a particle drift model that considers the main dispersion processes such as winds and currents, incorporating three land-based sources of plastic particles – wastewater discharge, rivers, and cities. 

Image credit: The researchers.

The findings showed that coastal zones were the hardest hit, both by macroplastics and microplastics (plastic pieces smaller than five millimeters). As MPAs tend to be closer to coastal zones, they accumulated more plastic waste than sites in offshore waters. Most plastics were traced back to land-based sources, which means the issue has to be tackled at source.

The average concentration of macroplastics in inshore waters was larger than five kilograms per squared kilometer, while offshore waters had over 1.5 kilograms. Meanwhile, average microplastics concentration in inshore waters was higher than 1.5 million particles per squared kilometer, and 0.5 million particles in offshore waters. 

“The most effective way to reduce plastic pollution in protected areas is by reducing marine litter at the sources. A management plan including litter reduction at its sources can occasionally be successfully implemented locally,” the researchers wrote, suggesting the use of a floating barrier installation and a pre-filtering device. 

The study was published in the journal Frontiers. 

Florida’s birds of prey are full of microplastics

A new study from the University of Central Florida (UCF) has found, for the first time, microplastics in terrestrial and aquatic birds of prey in the state.

Image credits Harry Burgess.

Some of the birds in whose digestive systems the team found microplastics include hawks, ospreys, and owls. The accumulation of such material can lead to starvation and poisoning, either of which can be life-threatening. The findings are particularly worrying because birds of prey are critical to a functioning ecosystem, the authors note.

A bird’s gut view

“Birds of prey are top predators in the ecosystem and by changing the population or health status of the top predator, it completely alters all of the animals, organisms and habitats below them on the food web,” says Julia Carlin, the study’s lead author and a graduate of UCF’s Department of Biology.

Microplastics are pieces of plastic that are under 5 mm in length, produced from the breaking down of larger pieces of plastic such as synthetic clothes, or that are purposely-made for use in industry, or for health and beauty products.

Plastic ingestion by wildlife was first noted in the 1960s, the team explains, adding that microplastic ingestion has come under increased scrutiny since 2010. Since then, microplastics have been found in the guts of fish, marine birds, filter-feeding invertebrates such as oysters, and humans.

Birds of prey, however, have not been studied for microplastic ingestion due to their protected status.

For the study, the team worked with the Audubon Center for Birds of Prey in Maitland, Florida where injured raptor birds are nursed back to health. This gave them a unique opportunity to study the stomach contents of 63 birds found across Florida that were dead when they arrived at the center or died 24 hours after they arrived.

Microplastics were found in the digestive systems of all the examined birds, totalling nearly 1,200 pieces of plastic. The most common microplastics found were microfibers (86%), which come from synthetic ropes and fabrics, and can be released into the environment from clothes-washing.

The most common colors seen were blue and clear, which the team says is likely caused by the birds confusing these colors with prey or materials that would be useful for nesting.

As for solutions, the team says removing plastic waste from open landfills (so birds can’t pick them up), retrofitting water treatment installations to capture microplastics, and switching to natural fibers in the clothing industry could all help.

The paper “Microplastic accumulation in the gastrointestinal tracts in birds of prey in central Florida, USA” has been published in the journal Environmental Pollution.

EU pushes for circular economy to have longer-lasting products

Produce, use, and throw away? No, better reduce, reuse, and recycle, says the EU. The paradigm of the current linear economic model could be coming to an end, replaced by a circular economy, a system that seeks to better use the resources available and reduce their environmental impact.

The European Commissioner for the Environment, Oceans and Fisheries, Virginijus Sinkevicius. Credit EU

The European Union (EU) wants to move forward in that direction and introduced a new Circular Economy Action Plan, with the objective of reducing the bloc’s consumption footprint and double its circular material use rate. By doing so, the EU’s GDP would increase an additional 0.5% by 2030.

“Only by changing the economic model can we hope for success, ease the pressure on our biodiversity and achieve the 2050 goals on carbon neutrality in the European Union (EU),” explained the European Commissioner for the Environment, Oceans and Fisheries, Virginijus Sinkevicius.

The EU acknowledged that many products are currently being manufactured in such a way that they break down fast and can’t be reused, repaired, or recycle. Instead, green products should be the norm, rewarding manufacturers of products based on their sustainability performance, according to the bloc’s plan.

In order to do that, the bloc wants to push for legislation to ensure the manufacturing of sustainable products in electronics and textiles. They should be designed to last longer, be easier to use, repair, and recycle and incorporate the maximum of recycled materials instead of new ones. Additionally, the EU aims to restrict single-use items, deal with planned obsolescence, and veto the destruction of unsold durable goods. Along these lines, consumers should have information on the life expectancy of the products and to what extent they can be repaired, in order to help them make greener purchases.

The EU also wants to improve the collection and treatment of electronic waste, establish new mandatory requirements for plastics — with special attention to microplastics — and encourage the use of more ecological construction elements and reusable articles that replace cutlery or single-use food packaging.

This will lead to less waste generated and minimize the amount of waste exported by the bloc, according to the plan, which would also include the development of a harmonized model for waste collection and threshing across the Union as well as labeling.

As an example, Sinkevicius said that the EU will “move in the direction of universal chargers“, for laptops, smartphones or tablets, so that when buying a new one it does not need to include a charging device. This will make it unnecessary to extract so many raw materials and boost the secondary market.

The initiative was welcomed by business leaders, grouped under the chamber BusinessEurope. They said in a press release that it’s a “win-win” proposal and that “minimizing the amount of waste and keeping the value of raw materials as long as possible is good for the environment and for companies.”

Magnetic coils, the new way to deal with microplastics

Flowing through rivers and oceans, plastic waste has become an important environmental threat across the globe. Trying to deal with the problem, researchers in Australia developed a way to purge water sources of microplastic without harming microorganisms, using a set of magnets.

Credit: Flickr

 

Microplastics are ubiquitous pollutants. Some are too small to be filtered during industrial water treatment, such as exfoliating beads in cosmetics, while others are produced indirectly when larger debris like soda bottles or tires weather amid sun and sand.

“Microplastics adsorb organic and metal contaminants as they travel through water and release these hazardous substances into aquatic organisms when eaten, causing them to accumulate all the way up the food chain,” said senior author Shaobin Wang, a professor at the University of Adelaide (Australia).

Wang and the research team generated short-lived chemicals, called reactive oxygen species, which trigger chain reactions that chop the polimers (long molecules) that makeup microplastics into tiny and harmless segments that dissolve in water. The study was published in the journal Matter.

The problem was reactive oxygen species are often produced using heavy metals such as iron or cobalt, which are dangerous pollutants in their own right and thus unsuitable in an environmental context. To get around this, they used carbon nanotubes laced with nitrogen to help boost the generation of reactive oxygen species.

“Having magnetic nanotubes is particularly exciting because this makes it easy to collect them from real wastewater streams for repeated use in environmental remediation,” says Xiaoguang Duan, a chemical engineering research fellow at Adelaide who also co-led the project.

The carbon nanotube catalysts removed a significant fraction of microplastics in just eight hours while remaining stable themselves in the harsh oxidative conditions needed for microplastics breakdown. Their coiled shape increased stability and maximized reactive surface area. Chemical by-products of this microplastic decomposition, such as aldehydes and carboxylic acids, aren’t major environmental hazards. The team, for example, found that exposing green algae to water containing microplastic by-products for two weeks didn’t harm the algae’s growth.

The next step of the research will be to ensure that the nano springs work on microplastics of different compositions, shapes, and origins, as all microplastics are chemically different. They also think that the byproducts of microplastic decomposition could be harnessed as an energy source for microorganisms.

“If plastic contaminants can be repurposed as food for algae growth, it will be a triumph for using biotechnology to solve environmental problems in ways that are both green and cost-efficient,” Wang says.

 

N. aromaticivorans bacteria.

Slightly-tweaked microbe could create plastics from a common plant waste material

A few genetic modifications can induce a strain of soil bacteria to convert a renewable material, lignin, into plastics. The best part? Lignin is so cheap and plentiful we don’t even bother trying to use it right now.

N. aromaticivorans bacteria.

N. aromaticivorans bacteria.
Image credits Great Lakes Bioenergy Research Center / UoW.

Woody plants show great promise as a potential replacement for petroleum in various uses — such as fuel, plastics, and chemical production. They contain a lot of sugars, which can be used for those applications, but they’re kept out of reach behind the cellulose in their cellular walls.

Those walls are so durable and hard (read: ‘expensive’) to break down industrially, that we generally don’t really bother extracting the materials.

Mister bacteria, break down this wall

A team of researchers at the Great Lakes Bioenergy Research Center (based at the University of Wisconsin-Madison-based and funded by the Department of Energy) hopes that a bacteria species can point the way to woody-plants-based replacements for petroleum. Their plan is to take this microscopic critter, tweak its genome around a bit, and unleash it on the plants’ cells — where it will transform all the lignin, a polymer that ties cellulose to the sugars, into something we can actually use.

Lignin is actually super abundant. It’s the second-most abundant type of aromatic compound (those ‘rings’ you see in organic chemistry) on the planet after petroleum, the team explains. However, isn’t very valuable right now. That’s actually an understatement. Lignin today is so cheap that paper mills — which have been in the business of stripping lignin from wood for centuries — can’t even bother trying to sell the stuff; they just dispose of it in huge boilers.

“They say you can make anything from lignin except money,” says Miguel Perez, a UW-Madison graduate student in civil and environmental engineering and the paper’s first author.

The bacteria in question is Novosphingobium aromaticivorans. It was first isolated in soils that were previously contaminated by petroleum products. And, in this environment where most other organisms find it hard to eek out a living, N. aromaticivorans was thriving. Its name aromaticivorans means ‘aromatic-eater’ as a nod to its unique adaptations.

Lignin is a large molecule that’s very difficult to break down into smaller pieces. But N. aromaticivorans already had a natural appetite for lignin-like products when discovered — in fact, it’s the only known organism so far that can digest many parts of the lignin molecule and excrete smaller aromatic compounds.

“Other microbes tried before may be able to digest a few types of aromatics found in lignin,” Perez says. “When we met this microbe, it was already good at degrading a wide range of compounds. That makes this microbe very promising.”

During this process, N. aromaticivorans produces 2-pyrone-4,6-dicarboxylic acid or PDC. The team engineered the bacteria by removing three genes in its genome, further stabilizing the digestion process and coaxing it reducing all its meal into PDC. In the end, what they obtained was an organism which could be fed any part of the lignin molecule and produce PDC.

“There’s no industrial process for doing that, because PDC is so difficult to make by existing routes,” says Daniel Noguera, the study’s corresponding author. “But if we’re making biofuels from cellulose and producing lignin — something we used to just burn — and we can efficiently turn the lignin into PDC, that potentially changes the market for industrial use of this compound.”

“The compound performs the same or better than the most common petroleum-based additive to PET polymers — like plastic bottles and synthetic fibers — which are the most common polymers being produced in the world,” Perez adds.

PDC is also biodegradable and doesn’t leach any by-products while it degrades.

For now, the engineered variation on N. aromaticivorans can turn at least 59% of lignin’s potentially useful compounds into PDC. The team suggests that a greater efficiency is possible through further genetic manipulation of the microbe. They’re currently at work implementing such changes and “might create a new industry,” Noguera says.

The paper “Funneling aromatic products of chemically depolymerized lignin into 2-pyrone-4-6-dicarboxylic acid with Novosphingobium aromaticivorans” has been published in the journal Green Chemistry.