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Microplastics in the soil point to another potential ecosystem collapse

When these particles are eaten by earthworms, the results are not good.

Photo by: Andia/ Universal Images Group via Getty Images
  • New research from Anglia Ruskin University states that microplastics in soil are causing earthworms to lose weight.
  • Soil affected by microplastics produces less crop yield due to less productive earthworms and lower pH levels.
  • If this trend continues, our entire agricultural system could be compromised.

In the last installment of "How Plastic is Destroying Us," we discussed the billions of microplastic particles being leeched from tea bags into your mug. It turns out such particles are turning up in the darndest places. A new study, published in Environmental Science & Technology, reveals another unfortunate locale: the digestive tract of earthworms.

Outside of fishing and post-rainy day sidewalks, most of us pay little attention to endogeic worms, the class of worms that live in the top soil. That doesn't mean they lack importance for our survival. By feeding on soil, these wiggly critters—Aporrectodea rosea, rosy-tipped earthworms—mix minerals and air into the soil, which helps, among other things, plants to sprout. Worms are an essential component of our agricultural system.

A team at Anglia Ruskin University in Cambridge wanted to know if the introduction of microplastics into the soil would stunt plant growth. Short answer: yes. After placing different microplastic fibers—biodegradable polylactic acid (PLA), conventional high-density polyethylene (HDPE), and microplastic clothing fibers—into the soil, they planted perennial ryegrass (Lolium perenne). Fewer seeds germinated.

Microplastic contamination is a growing concern for soil health, yet, as the team writes, it has not been well-studied. Fertilizer made from sewage sludge, rain, and airborne fallout are all means for these particles to settle into the earth. The long-term impact could include stunted soil biodiversity.

Microplastics are everywhere | Sarah Dudas | TEDxBinghamtonUniversity

We often mistake broad names for processes as "extra." For example, dark matter, which represents 85 percent of all matter in the universe, is believed to non-baryonic, yet physicists recognize that it could be comprised of subatomic particles we haven't yet discovered. The universe isn't know for creating filler; usually, our own ignorance is the culprit.

"Dirt" and "soil," to non-farmers at least, are often treated as an earth layer; referencing it is often in the negative, as when a parent scolds a child for "playing in the dirt." But soil is a process, living and organic, dependent on decaying and dead matter constantly being churned through (by earthworms, for example) and recycled.

Soil is one of the major reasons that America has become a global power. Our fields supply an incredible amount of food for the planet. By contrast, China, with its billion-plus population to feed, struggles to produce adequate amounts of nutrition due to less fertile soil. This is, in fact, one of the undiscussed underpinnings of the current "trade war."

Damaged soil destroys not only ecosystems, but societies as well. When famers try to increase crop yield by introducing plastic mulches and irrigation, they're unknowingly polluting the soil with tons of microplastic particles. These particles are then ingested by earthworms (among other animals), causing them to lose weight.

The research team chose the most important grass grown in temperate regions; in grassland ecosystems ryegrass is abundant. A variety of ecosystems were used, some with added microplastics, one control without. Earthworms were most affected by HDPE microplastics, though any of the added particles made life worse for the worms.

Beach covered in microplastics

A view of the Schiavonea beach with microplastics, transported by the Ionian sea during the last sea storm.

Photo by Alfonso Di Vincenzo/KONTROLAB /LightRocket via Getty Images

Soil is generally low in nutrient value, meaning that worms have to eat and pass a lot of it for their existence. The team compares the results to aquatic environments, in which the digestive tracts of fish, like worms, are obstructed and worn away. The consumption of microplastic particles stunts their growth while compromising the survival of the organism.

Beyond worms, the particles (especially HDPE) decrease soil pH. This directly affects the diversity of organisms living there. As with the human microbiome, in which a diverse population of bacteria is healthiest, soil pays a steep price when diversity drops.

These particles don't remain in the soil; they end up, in some cases, on your plate. The team writes,

"In agricultural settings, such effects may have implications for the production and quality of crop plants, by directly affecting plant development and altering the soil environment in which they are produced as well as having potential implications for human health through the accumulation of microplastics and harmful compounds in the tissues of plants."

All plastics are biodegradable. The problem is, some take weeks to mineralize while others hang around for millions of years. Until we implement broad solutions that implement a shelf life for plastics, these particles aren't going anywhere—except inside of our digestive tracts, eventually. As with worms, such news doesn't look good for the health of our species.

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Hints of the 4th dimension have been detected by physicists

What would it be like to experience the 4th dimension?

Two different experiments show hints of a 4th spatial dimension. Credit: Zilberberg Group / ETH Zürich
Technology & Innovation

Physicists have understood at least theoretically, that there may be higher dimensions, besides our normal three. The first clue came in 1905 when Einstein developed his theory of special relativity. Of course, by dimensions we’re talking about length, width, and height. Generally speaking, when we talk about a fourth dimension, it’s considered space-time. But here, physicists mean a spatial dimension beyond the normal three, not a parallel universe, as such dimensions are mistaken for in popular sci-fi shows.

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A new hydrogel might be strong enough for knee replacements

Duke University researchers might have solved a half-century old problem.

Lee Jae-Sung of Korea Republic lies on the pitch holding his knee during the 2018 FIFA World Cup Russia group F match between Korea Republic and Germany at Kazan Arena on June 27, 2018 in Kazan, Russia.

Photo by Alexander Hassenstein/Getty Images
Technology & Innovation
  • Duke University researchers created a hydrogel that appears to be as strong and flexible as human cartilage.
  • The blend of three polymers provides enough flexibility and durability to mimic the knee.
  • The next step is to test this hydrogel in sheep; human use can take at least three years.
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Predicting PTSD symptoms becomes possible with a new test

An algorithm may allow doctors to assess PTSD candidates for early intervention after traumatic ER visits.

Image source: camillo jimenez/Unsplash
Technology & Innovation
  • 10-15% of people visiting emergency rooms eventually develop symptoms of long-lasting PTSD.
  • Early treatment is available but there's been no way to tell who needs it.
  • Using clinical data already being collected, machine learning can identify who's at risk.

The psychological scars a traumatic experience can leave behind may have a more profound effect on a person than the original traumatic experience. Long after an acute emergency is resolved, victims of post-traumatic stress disorder (PTSD) continue to suffer its consequences.

In the U.S. some 30 million patients are annually treated in emergency departments (EDs) for a range of traumatic injuries. Add to that urgent admissions to the ED with the onset of COVID-19 symptoms. Health experts predict that some 10 percent to 15 percent of these people will develop long-lasting PTSD within a year of the initial incident. While there are interventions that can help individuals avoid PTSD, there's been no reliable way to identify those most likely to need it.

That may now have changed. A multi-disciplinary team of researchers has developed a method for predicting who is most likely to develop PTSD after a traumatic emergency-room experience. Their study is published in the journal Nature Medicine.

70 data points and machine learning

nurse wrapping patient's arm

Image source: Creators Collective/Unsplash

Study lead author Katharina Schultebraucks of Columbia University's Department Vagelos College of Physicians and Surgeons says:

"For many trauma patients, the ED visit is often their sole contact with the health care system. The time immediately after a traumatic injury is a critical window for identifying people at risk for PTSD and arranging appropriate follow-up treatment. The earlier we can treat those at risk, the better the likely outcomes."

The new PTSD test uses machine learning and 70 clinical data points plus a clinical stress-level assessment to develop a PTSD score for an individual that identifies their risk of acquiring the condition.

Among the 70 data points are stress hormone levels, inflammatory signals, high blood pressure, and an anxiety-level assessment. Says Schultebraucks, "We selected measures that are routinely collected in the ED and logged in the electronic medical record, plus answers to a few short questions about the psychological stress response. The idea was to create a tool that would be universally available and would add little burden to ED personnel."

Researchers used data from adult trauma survivors in Atlanta, Georgia (377 individuals) and New York City (221 individuals) to test their system.

Of this cohort, 90 percent of those predicted to be at high risk developed long-lasting PTSD symptoms within a year of the initial traumatic event — just 5 percent of people who never developed PTSD symptoms had been erroneously identified as being at risk.

On the other side of the coin, 29 percent of individuals were 'false negatives," tagged by the algorithm as not being at risk of PTSD, but then developing symptoms.

Going forward

person leaning their head on another's shoulder

Image source: Külli Kittus/Unsplash

Schultebraucks looks forward to more testing as the researchers continue to refine their algorithm and to instill confidence in the approach among ED clinicians: "Because previous models for predicting PTSD risk have not been validated in independent samples like our model, they haven't been adopted in clinical practice." She expects that, "Testing and validation of our model in larger samples will be necessary for the algorithm to be ready-to-use in the general population."

"Currently only 7% of level-1 trauma centers routinely screen for PTSD," notes Schultebraucks. "We hope that the algorithm will provide ED clinicians with a rapid, automatic readout that they could use for discharge planning and the prevention of PTSD." She envisions the algorithm being implemented in the future as a feature of electronic medical records.

The researchers also plan to test their algorithm at predicting PTSD in people whose traumatic experiences come in the form of health events such as heart attacks and strokes, as opposed to visits to the emergency department.

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How often do vaccine trials hit paydirt?

Vaccines find more success in development than any other kind of drug, but have been relatively neglected in recent decades.

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