Health and Medicine – Greg Laden's Blog https://gregladen.com/blog Thu, 14 Apr 2022 00:40:44 +0000 en-US hourly 1 https://wordpress.org/?v=6.4.8 https://i0.wp.com/gregladen.com/blog/wp-content/uploads/2017/10/Greg_Ladens_Blog_Favicon_black_GLb.png?fit=32%2C32&ssl=1 Health and Medicine – Greg Laden's Blog https://gregladen.com/blog 32 32 77525483 What happens if I eat mold? https://gregladen.com/blog/2022/04/17/what-happens-if-i-eat-mold/ https://gregladen.com/blog/2022/04/17/what-happens-if-i-eat-mold/#comments Sun, 17 Apr 2022 12:19:50 +0000 https://gregladen.com/blog/?p=9389 Continue reading What happens if I eat mold? →]]> A common concern people have is the outcome of eating food that is moldy. This happens when you are not paying attention to what you are eating and suddenly realize that you just ate half a sandwich made with bread that has some mold on it. Then you go “Oh, crap, I just ate some mold” and then you google it to find out if you are going to die ….

As with all things you eat, the first thing that must be said is this: If you are allergic to it, then you probably shouldn’t have eaten it. But, we’ll ignore that because if you are actually allergic to “mold” (or some subset of molds) than you already know what to do or not do.

Otherwise, the answer to the question is: There’s good news and bad news. First the good news. Mold is generally not bad for you (some molds are even good for you, or otherwise enhance food, as in those fancy smelly French cheeses). If you ate mold, just don’t worry. If you feel sick then maybe the mold is a problem, but most likely it isn’t.

Keep in mind, being less concerned with mold than one automatically might applies mainly to mold that was not sufficient in quantity or yuckiness to notice it BEFORE you took a bite, and even during the biting process. In other words, this does not necessarily apply to cases such as the above depicted bread.

Check out: The IKONOKAST Science Podcast. Excellent interviews with top scientists.

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The bad news is simple: If the food is moldy, then it may be old and otherwise contaminated with bacteria and stuff that is not good for you. If you are in a high risk group for such things, or pregnant and trying to avoid listeria, etc., then you might want to avoid old rotten food, and the mold itself, while not harmful, is a clue that the food is old.

As a general rule, soft food is more risky if it is moldy, while hard food (like hard cheese) can be cleaned up by scraping or slicing away the moldy part.

In my personal opinion, First Worlders are more worried about rotten food than they need to be, and throw away a lot of perfectly good food. Try to be less squeamish and check your priv before discarding things that scare you.

Some books related to mold and things moldy:

Kid’s science book: Cell and Microbe Science Fair Projects: Using Microscopes, Mold, and More (Biology! Best Science Projects)

Fungi: Mushrooms, Toadstools, Molds, Yeasts, and Other Fungi (Class of Their Own (Paperback))

The Mold in Dr. Florey’s Coat: The Story of the Penicillin Miracle

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]]> https://gregladen.com/blog/2022/04/17/what-happens-if-i-eat-mold/feed/ 5 9389 How an epidemic (or pandemic) starts https://gregladen.com/blog/2022/02/26/how-an-epidemic-or-pandemic-starts/ https://gregladen.com/blog/2022/02/26/how-an-epidemic-or-pandemic-starts/#comments Sat, 26 Feb 2022 20:32:45 +0000 https://gregladen.com/blog/?p=34342 Continue reading How an epidemic (or pandemic) starts →]]> Years ago Ebola made itself known to scientists, when it appeared simultaneously in the Sudan and Zaire. The two events were a very long way from each other. It happens that I am very familiar with that part of the map, and I’m certain that any attempt to go from Nzara, Sudan, to Yambuku Zaire on land would take several weeks and, actually, be impossible. It could not happen casually. For a while, experts thought a particular person who was probably patient zero at Yambuku had made the trip, despite no evidence for him having done so. In the end, most ebola experts simply stopped thinking about this conundrum. A few of us working in the area, though, had a different idea. Animal-born (we thought fruit bat) ebola spread in the animal first, and conditions emerged that heightened the chance of a jump to humans also spread, so there were two separate jumps. Likely, this could happen now and then, with several jumps within a few weeks time, but only during those few weeks time when conditions were just right. The trick to managing future ebola outbreaks might be to figure out what those conditions might be, and at least, set up a warning system. But, since epidemiology worked at the time entirely on the pump model, one source, one initial spread, that sort of thinking never happened.

If that is typical for zoonotic diseases (even if not inevitable in every case) it presents a slightly different view than what one usually conjures up. It is not the case that an animal sneezes or bleeds (or whatever) on a human, then that humna, patient zero spreads the disease to other humans. Rather, the condition of transfer from an animal reservoir becomes temporarily highly likely insead of almost impossible, and perhaps dozens of transfers happen, of which, one or two or three, perhaps, are traced to eventually by epidemiologists.

Turns out that is what probably happened with Covid-19. The transfer happened twice, over just a few weeks time. The best explanation for this is that some animal species (could be more than one) had their own epidemic of this particular coronavirus strain going on, and there happen to be a big market with this animal species (or species) on sale, and the rest is history.

There are two studies, this one and this one, seem to support this idea. When the disease experts are done being incredibly busy with Covid, maybe they can go back to Sudan/Congo and rethink the initial appearance of Ebola with this model, now no longer just some zany idea a few of us had years ago, in mind.

]]> https://gregladen.com/blog/2022/02/26/how-an-epidemic-or-pandemic-starts/feed/ 9 34342 Punch Covid In The Face with Money https://gregladen.com/blog/2021/12/31/punch-covid-in-the-face-with-money/ https://gregladen.com/blog/2021/12/31/punch-covid-in-the-face-with-money/#comments Fri, 31 Dec 2021 14:59:25 +0000 https://gregladen.com/blog/?p=34296 Continue reading Punch Covid In The Face with Money →]]> The global, and American, research programs in health and biology over recent decades have given us inadequate tools to understand the Covid virus as fully and quickly as I think we could have. We need:

  • …more basic research on viruses, never mind the virus
  • …more basic research on infections, never mind the pathogen, the host, or even the severity of the disease
  • …a research center on T cells, another on B cells, another on NK cells, another on the lymph system, if that is what it takes
  • For every working vaccine for an existing vaccine there should be 1000 vaccines made up just for the fun of learning what and how and if and everything one learns while making things.
  • Pathogen researchers should be producing experimental just-for-fun vaccines like Linux geeks produce operating systems or distros. So when a new pathogen comes along, the best vaccine response, you can order on Amazon.
  • Very little of these basic research approaches has been the subject of targeted research. This is the fallacy of targeted research. Targeted research alone is not how we address the Next Big Thing.
  • In the US, the NIH,NSF, and all the other research funding and oversight agencies, and the research arms of all the scientific agencies such a the USGS, NOAA, DOE,etc. are INFRASTRUCTURE and their funding should be TRIPLED.

Let’s throw money at this thing!

]]> https://gregladen.com/blog/2021/12/31/punch-covid-in-the-face-with-money/feed/ 1 34296 Children of Covid https://gregladen.com/blog/2021/12/30/children-of-covid/ https://gregladen.com/blog/2021/12/30/children-of-covid/#comments Thu, 30 Dec 2021 18:47:16 +0000 https://gregladen.com/blog/?p=34293 Continue reading Children of Covid →]]> In Minnesota, our surge peaked just before Thanksgiving. Then it unpeaked and went higher. Then is started to go down a little, then Xmas, and it unpeaked again and is probably going to go higher by the weekend. Just in time for the New Years resurgence, which would result in a peak-on-top-of-peak happening about January 8th.

But, that peak will be nothing compared to the Superpeak that will pile on top of that one, because Omicron will sweep through the region. Expect the biggest peak ever to pretty much coincide with the month of January.

And this is really going to mess up school in January. World epidemic expert Michael Osterholm was recently asked what should happen in schools. He was essentially unable to answer because the question is so ridiculous, framed as it is as a request for options. There are no options. He did say, “We may think we are done with Covid, but Covid is not done with us.”

For those who don’t know, the following are entirely or mostly true, as far as I know:

1) 1 In X P-12 teachers will be out with Covid in January.

2) 1 in Y P-12 teachers will be unable to go to work because their daycare shuts down because of Covid in January.

(X and Y are unknown but the ratio is not insignificant.)

3) Same for administrators and students, at various levels.

4) There are no substitutes. That is not the beginning of a sentence where the next word is “for” like “there are no substitutes for good study habits.” There are no substitutes, as in substitute teachers. Short term subs are gone, long term subs were hired up as teachers long ago.

5) There are very few, if any, new teachers coming in to replace those who retired, went crazy and ran away, or died, during this pandemic. Our society has shoved its problems up the nether regions of teachers for long enough, Covid is the last straw, only an idiot would become a teacher these days, and most possible teachers are not idiots. Maybe they will go be truck drivers. So, there is probably a rapidly growing systemic shortage of teachers going on independently of Covid, made worse by Covid.

By mid January we are going to be herding the kids who show up to school into large rooms where cameras controlled by Covid-riddled deans working from home will watch them during the school day, after which they will be picked up by their parents because whatever is left of the school bus system is going to collapse again.

Now’s your chance, Children of Covid! You don’t need no education!

]]> https://gregladen.com/blog/2021/12/30/children-of-covid/feed/ 3 34293 Covid Vaccines Confer Better Immunity Than Getting The Disease https://gregladen.com/blog/2021/11/09/covid-vaccines-confer-better-immunity-than-getting-the-disease/ https://gregladen.com/blog/2021/11/09/covid-vaccines-confer-better-immunity-than-getting-the-disease/#comments Wed, 10 Nov 2021 01:15:54 +0000 https://gregladen.com/blog/?p=34214 Continue reading Covid Vaccines Confer Better Immunity Than Getting The Disease →]]> We know that Covid vaccines reduce the risk of future infection by over 200%, and also reduce the severity of infection, compared to getting the disease. The official current thinking by the CDC is that vaccines are better than natural infection for Covid-19, based on that research and other considerations. (Added: See also this [thanks Yana!])

Surely, getting Covid would, for most people, cause a certain degree of immunity. That is what the immune system is for, after all. A vaccine imitates that process. It is entirely conceivable that getting a disease would be better than vaccinating in some cases. Remember the 2009 influenza epidemic? One study showed that getting that strain of influenza conferred better immunity than the vaccine available at the time.

The logic behind infection being better than a vaccine is usually this: The body responds, possibly, to multiple, and different, molecular configurations on the infectious agent, and learns to recognize them. A vaccine is almost always targeted to a smaller set of molecular configurations, so naturally a vaccine would not prime the immune system in as many different ways as the infection would.

That is a nice logical argument, but the empirical data clearly indicates it is wrong. The available vaccinations work better than infection in creating immunity. So why is this true?

I don’t think we fully understand this yet, but I’ll offer two lines of thinking. First, the somewhat more obscure but possibly very important. Remember, despite the fact that reporters and even doctors (and Facebook and Twitter self styled experts) only know about one part of the multi-part immune system, the b cell mediated anti-body response to an infection. There are other pars as well, including the t cell response, which amounts to t cell mediated death of infected cells, and the memory system for both t and b cell systems. Both of these systems work in concert with other aspects of the immune system, that involve for example cells that find a pathogen and bring it to specific sites in the body where it is interrogated, and responded to.

There is research to suggest that for some diseases (not Covid specifically but other respiratory viruses) an infection may elicit a very rapid response by the t cell system, which does the infection in fast enough that the b cell system does not fully develop an “evolved” memory response to use later in the event of a second infection. However, over time, with repeated infections, all of the various parts of the adaptive immune system figure it out and fully respond, and now the individual has excellent immunity.

Personally I suspect that this explains the curious phenomenon that no children or young adults are zero percent likely to get a cold, but lots of people in their 70s or older claim that they never had a cold in their lives. They did, they forgot, and in the mean time, their immune system developed a strong response to common colds. This is an untested hypothesis, so don’t go around thinking it just yet.

The larger point is this. If that research is meaningful, it may be the case that the immune system is capable of tripping over itself, so a natural infection produces a less than idea result. Meanwhile, a vaccine is designed to not do that. Remember, if we have a few vaccines for a given infection, those vaccines represent a small subset of many potential vaccines that were tried out and either gave indications of ineffectiveness or bad side effects. Perhaps those earlier variants of the vaccine are analogous to less than effective immune responses to natural infection.

Which is a nice segue into the second idea. Imagine a target in a shooting range, one of those outlines of the body with a few areas designated (by bull’s eye symbols) as places to shoot. Imagine firing a gun semi-randomly at the target and maybe hitting it in a few places. If you do that a bunch of times, you may now and then accidentally hit the head, and have a clean kill. All the other shots are either totally ineffective, or only “wound” the target. That is natural immunity to a natural infection.

Alternatively, you shoot the target in the head once and it is dead. One bullet, one shot, but a perfect shot aimed at exactly where you have to shoot to have the best result. That is a carefully designed vaccine. It doesn’t matter how many other body parts (surface configurations of molecules on a virus) the natural immunity responds to, if there is one main configuration (in this case, part of the spike protein) that the vaccine focuses on. And no, the virus doesn’t easily mutate in such a way that the spike protein is different enough that it can’t be targeted. This is a part of the virus that is highly conserved. It cant change much, or the individual virus with the change can’t reproduce. A target can’t exist without a head. It will always have a head, and if you can always hit the head, then you always win, and all the other strategies are lesser.

]]> https://gregladen.com/blog/2021/11/09/covid-vaccines-confer-better-immunity-than-getting-the-disease/feed/ 35 34214 Covid Contaminants Harm Self https://gregladen.com/blog/2021/09/27/covid-contaminants-harm-self/ https://gregladen.com/blog/2021/09/27/covid-contaminants-harm-self/#comments Mon, 27 Sep 2021 11:05:52 +0000 https://gregladen.com/blog/?p=34044 Continue reading Covid Contaminants Harm Self →]]>
Republican Contaminants are killing Americans at the rate of about one half million per year, because of their pro-Covid stance. But they are killing more of their own.
This is probably not a self correcting phenomenon. Not enough Contaminants are dying of Covid to change election outcomes. But a precinct by precinct study may reveal a small effect.

“John Nolte argued that the partisan gap in vaccination rates was part of a liberal plot. Liberals like Biden, Nancy Pelosi, Anthony Fauci and Howard Stern have tried so hard to persuade people to get vaccinated, because they know that Republican voters will do the opposite of whatever they say, Nolte wrote.”

This would be funny if it wasn’t so …. no wait, this is actually just really funny.

Source: New York Times “The Mornting” September 27, 2021, byline: David Leonhardt

]]> https://gregladen.com/blog/2021/09/27/covid-contaminants-harm-self/feed/ 2 34044 This ain’t the Washita River, General https://gregladen.com/blog/2021/09/20/this-aint-the-washita-river-general/ https://gregladen.com/blog/2021/09/20/this-aint-the-washita-river-general/#comments Tue, 21 Sep 2021 02:15:30 +0000 https://gregladen.com/blog/?p=34030 Continue reading This ain’t the Washita River, General →]]> A growing number of Contaminants (aka Republicans aka Magatrumpers) believe that Liberals and Democrats are pushing vaccines in order to make conservatives and yahoos dislike and therefore avoid vaccines, so that on election day, more Republicans are dead of Covid than Democrats.

Maybe we are doing that, maybe we are not. Not my job to tell you. I am not the mule skinner.

]]> https://gregladen.com/blog/2021/09/20/this-aint-the-washita-river-general/feed/ 7 34030 Covid Poems: Odes to odious antivaxers https://gregladen.com/blog/2021/08/28/covid-poems-odes-to-odious-antivaxers/ https://gregladen.com/blog/2021/08/28/covid-poems-odes-to-odious-antivaxers/#comments Sat, 28 Aug 2021 23:07:05 +0000 https://gregladen.com/blog/?p=33959 Continue reading Covid Poems: Odes to odious antivaxers →]]> I feel sorry for some of these people, esp the couple with the dogs. Some of the others? Might as well be Nikolas Cruz, since their choices result in the death of innocent children. But they are all doing one thing well: Serving as object lessons. Don’t be a dumbass.

]]> https://gregladen.com/blog/2021/08/28/covid-poems-odes-to-odious-antivaxers/feed/ 7 33959 Everyone in the US will be vaccinated by early August. https://gregladen.com/blog/2021/02/28/everyone-in-the-us-will-be-vaccinated-by-early-august/ https://gregladen.com/blog/2021/02/28/everyone-in-the-us-will-be-vaccinated-by-early-august/#comments Sun, 28 Feb 2021 20:47:11 +0000 https://gregladen.com/blog/?p=33721 Continue reading Everyone in the US will be vaccinated by early August. →]]> Everyone eligible and who wants to, that is.

Have a look at this line. I call it “line going up.” Feel free to download it and use it for your own purposes.

This line. It is going up.

I ask you to consider the following questions. Assume the vertical scale on the y-axis is 10:

1) What is the average value of this line?

2) What is the average value of the last 20% of the line, over to the left?

3) Assume the “line going up” is in fact upward-going indefinitely. This is the first ten units of time. What will be the average value of the second ten units of time?

4) Given the same assumption, what is the average value of all 20 units of time?

5) If you were asked to predict the total magnitude (all the areas under the curve) for all of the curve, for the next 10 units of time only, what would it be?

Answers:
1: about 5.
2: About 8
3: About 15
4: About 10
5: A lot, but it runs from about 10 to about 20, so if it is that many units per day, about 150 (the average of 10 and 20 times 10).

I know you got all those questions right. So, now that we can do baby analytical geometry and statistics, have a look at this:

This graph shows an upward trend. We know the trend is somewhat open-ended up to about 7 million a day, with new vaccines coming on line. The drop before the recent mode, which casues an average that would have been about 2.0 million per day, was caused by a preternatural natural disaster (Texas). So, the best estimate of curent production is much closer to 2.5, not 1.7, and that rate will continue to go up so in about four weeks it will be closer to 4 million a day. This is not just based on me looking at the graph and sucking my thumb. This is what the experts are saying. April through July would be 600 million doses, many of which would be one shot doses of the newest vaccines. In other words, every eligible person in the US will be vaccinated by the end of July, comfortably.

That is a very conservative estimate.

Why to people take perfectly good data combined with clear projections from the health experts and turn them into bald face lies? Oh, it is not a lie you say, just a mistake. No, I reply, it is impossible to make a mistake like this and publish it in bloomberg. This is a lie, designed to get a rise out of the readership, and that lie regardless of its intent will contribute to the gloom and doom and that has consequences.

]]> https://gregladen.com/blog/2021/02/28/everyone-in-the-us-will-be-vaccinated-by-early-august/feed/ 7 33721 The Complex Problem of Microplastic Particle Pollution https://gregladen.com/blog/2021/02/19/the-complex-problem-of-microplastic-particle-pollution/ https://gregladen.com/blog/2021/02/19/the-complex-problem-of-microplastic-particle-pollution/#comments Fri, 19 Feb 2021 16:13:14 +0000 https://gregladen.com/blog/?p=33673 Continue reading The Complex Problem of Microplastic Particle Pollution →]]> The importance of microplastic particles in the ecosystem, both as they might effect ecological systems and human health, is the subject of great deal of new research, and is one of more rapidly developing areas of of knowledge related to environmental concern. Once thought of as mainly a problem in the oceans (related to the now famous “Pacific Garbage Patch“) it is now understood that microplastic particles are also common in the terrestrial ecosystem and the part of the food chain we eat.

Microplastic fluxes and associated ecosystem feedbacks: Deposition and accumulation of microplastics can affect soil properties, with consequences for process rates and net primary production (NPP), causing feedbacks to the atmosphere, including greenhouse gases (GHGs). So far, nanoplastic has unknown consequences for this system. Fig 1 from “Microplastics in Terrestrial Ecosystems” Rillig and Lehmann 2020. Science. GRAPHIC: A. KITTERMAN/SCIENCE FROM M. C. RILLIG AND A. LEHMANN

Sources of microplastic particles include wearing down of tires, the use of synthetic textiles, road paint, the coatings and pain used on boats, and personal care products (roughly in that order) as well as “city dust,” a ‘generic name given to a group of nine sources” including the soles of footwear, synthetic cooking utensils, building paint, cleaning supplies, etc, all with small individual contributions but collectively about 24% of the microplastic particle pollution observed in the ocean. (See this.)

Estimated contribution of various sources to the microplastic particle pollution observed in the oceans. Source: Primary microplastics in the oceans, IUCN (see link in text).

The effects of microplastic particles may be more related to size and shape of the particles, rather than toxicity. (But all these factors matter.) Microplastic particles are mostly made of carbon. Normally carbon gets spread around the environment as part of the photosynthetic segment of the carbon cycle. Microplastic particles now exist in what has become known of as the “plastic cycle.” (See this and this.) Since the nature of microplastic routed carbon is different than “natural” carbon, direct and indirect effects on ecology can occur. Soil structure can be affected (including the spaces where air or water may be trapped in soil). Microplastics in soil can benefit plants, because soil density is lowered, so root growth is easier. However, where microplastics make up a large proporation of fill, plant growth is reduced (see this).

Note that the carbon in microplastic particles is fossil carbon, which prior to the manufacture of the plastic was mostly trapped in petroleum or coal, which in turn is mostly out of the short and medium term carbon cycle. Moving carbon from the long term cycle (which involves processes like continents being subjected into the mantle of the Earth, to be belched out later from volcanoes or added to spreading sea floors) into the short and medium term cycle (such as the cycle affected by human activity to cause global warming) may be important.

Microplastic particle contamination has been associated with changes in the immune system, the spread of antibiotic resistant bacteria (in part because bacterial microfilms that cover microplastic particles may favor, or at least contain, resistant forms), and microplastic particles have been found all over the place. Microplastic particles can be a vector moving chemicals between parts of the ecosystem.

Conceptual model of the plastic pollution cycle and the interactions between biogeochemistry, trophic transfer, and human health and exposure. Note that arrows and artwork are not to scale and are for descriptive purposes only. Expanded, adapted, and redrawn, in part, from Rochman et al. (2019) with permission. Fig 1 in Environ. Sci. Technol. 2019, 53, 13, 7177-7179

See “Microplastic in terrestrial ecosystems” for a fuller review of the effects of microplastic particles in soils and other parts of the ecosystem. It is pretty complex.

We may tend to think of microplastic particles as being a problem because we use plastic containers, which can break down into micro particles. That is true. For example, using polypropylene bottles in the preparation of infant formula releases microplastic particles into the formula itself. But a lot of microplastic particles are introduced directly into the environment because we make and use those small sized particles in a range of applications including agriculture and cosmetics. As a rule where the material being used is less solid, the degree to which it is soluble and thus the ease with which it enters the environment increases. This could allow regulations to be focuses more stridently and more quickly on areas of plastic use and production that have the most effect.

The universe of polymer species from primary microplastics to functional polymers, where solidity decreases, and solubility increases from polymer pellets to dispersion aids. Fig one in “Microplastic regulation should be more precise to incentivize both innovation and environmental safety” Nature October 21 2020.

Microplastic particles can be taken in to cells by a process called “internalization” or “endocytosis” (synonyms) (see abstract below). There is evidence that “fresh” microplastic particles are not easily taken in but once exposed to the environment for a while, the surface of the microplastic particles changes, allowing internalization to happen more easily. The effects of the microplastic on the inside of the cell is understudied, but could in some cases be a problem. Microplastics may decrease cellular activity and increase reactive oxygen species, which in turn has potentially serious health effects.

Is this hopeless? Possibly. Can we stop using plastics? Maybe. Can the environment sequester microplastic particles (and thus carbon) naturally? Sometimes and maybe. Developing nations contribute hugely to plastic pollution due to a lack of solid waste infrastructure. Developed nations like the US have a great plastic waste infrastructure, but use so many plastics that the contribution from these countries is still huge (see this). We shed microplastic particles through many activities from feeding one’s baby to driving to the store to buy more forumla.

The fact that microplastic particles are something we ingest, breath in, our that our cells engulf is not itself a novelty. The gas and liquids we exist among are normally full of particles. Many of these particles are polymers, like plastic, but natural (pollen, skin cells, etc.). The problem with microplastic particles isn’t so much that they exist, but that they exist and are subtly, or sometimes dramatically, different than what is normally there, and what we thus normally adapt to. Also, microplastic particles may create a different distribution than what would normally occur (like the frequency in baby formula?). The challenge is to figure out where microplastic particles matter most, and then figure out ways of addressing those problems first and fast. This will also involve figuring out if the best solutions (which is a function of how well the solution works and how likely it is to get it to happen) is a change in specific policies or regulations, or changes in individual behavior. And, of course, we must be cognizant that changes to avoid or reduce microplastic particles do not result in some other negative effect.

This is just a rough, preliminary look at microplastic particles. I tried to include a wide selection of links to recent works, but I’m afraid many may be behind paywalls. But, you should be able to find a lot more by CLICKING HERE.

Additional Info and Resources:
Machado, Et Al. 2018. Impacts of microplastics on the soil biophysical environment. Environ. Sci Technol 52(17)

Abstract: oils are essential components of terrestrial ecosystems that experience strong pollution pressure. Microplastic contamination of soils is being increasingly documented, with potential consequences for soil biodiversity and function. Notwithstanding, data on effects of such contaminants on fundamental properties potentially impacting soil biota are lacking. The present study explores the potential of microplastics to disturb vital relationships between soil and water, as well as its consequences for soil structure and microbial function. During a 5-weeks garden experiment we exposed a loamy sand soil to environmentally relevant nominal concentrations (up to 2%) of four common microplastic types (polyacrylic fibers, polyamide beads, polyester fibers, and polyethylene fragments). Then, we measured bulk density, water holding capacity, hydraulic conductivity, soil aggregation, and microbial activity. Microplastics affected the bulk density, water holding capacity, and the functional relationship between the microbial activity and water stable aggregates. The effects are underestimated if idiosyncrasies of particle type and concentrations are neglected, suggesting that purely qualitative environmental microplastic data might be of limited value for the assessment of effects in soil. If extended to other soils and plastic types, the processes unravelled here suggest that microplastics are relevant long-term anthropogenic stressors and drivers of global change in terrestrial ecosystems.

Ramsperger et al. 2020 “Environmental exposure enhances the internalization of microplastic particles into cells” Science Advances 6(50)
Abstract: Microplastic particles ubiquitously found in the environment are ingested by a huge variety of organisms. Subsequently, microplastic particles can translocate from the gastrointestinal tract into the tissues likely by cellular internalization. The reason for cellular internalization is unknown, since this has only been shown for specifically surface-functionalized particles. We show that environmentally exposed microplastic particles were internalized significantly more often than pristine microplastic particles into macrophages. We identified biomolecules forming an eco-corona on the surface of microplastic particles, suggesting that environmental exposure promotes the cellular internalization of microplastics. Our findings further indicate that cellular internalization is a key route by which microplastic particles translocate into tissues, where they may cause toxicological effects that have implications for the environment and human health.

Rilling and Lehman. 2020. Microplastic in terrestrial ecosystem. Science.

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