"Plastics are showing up in the world’s most remote places, including Mount Everest" and "How much plastic floats in the Great Pacific Garbage Patch?"

 Posted by Harrison Smith

Plastics are finding a way into the most extreme and isolated landscapes that Planet Earth has to offer. Plastics, or rather microplastics, have been found in the snow of Mount Everest. Majority of the plastics were found to be polyester fibers, likely originating from clothes of human hikers. Supporting this claim, it was found that snow from the base camp had a high concentration of plastic particles. The base camp is a common place for hikers to congregate, so it is reasonable that there is a high concentration of microplastics in this area shedding from their clothes. Nonetheless, plastic was found as high as 8,440 meters above sea level, only 400 meters from the summit of the tallest peak on the planet.

Plastic has also been found in some of the deepest depths of the sea, in the Mariana Trench. Plastics were found as deep as 10,890 meters below sea level, far below the penetrable reach of sunlight. The worst part? These plastics were found inside of animals. In one 2019 study, 90 crustaceans deep in the Pacific were analyzed for plastic contaminants. Of these 90 crustaceans, 65 were found to have microplastics inside of them. It is obvious that human waste is reaching the furthest corners and most hidden nooks and crannies of our planet.

Apart from the Mariana Trench and Mount Everest, plastics have been found in places far from any usual human activity. Plastics have been found in alarming amounts at an isolated meteorological station in the Pyrenees Mountains. Specifically, 365 microplastic particles per day rain down on each square meter at the station. That is as much as some cities! These particles are estimated to travel 95 km due to wind propulsion before landing at the remote meteorological station in the Pyrenees Mountains. This 95 km distance is based on simulations that consider wind speed and direction.

Now I know what some of you may be thinking. 365 particles per square meter in a remote location? How is that possible? Well we are not talking about Tupperware or water bottles here. We are talking about microplastics. Microplastics, as defined by this article, are any

plastic pieces smaller than 5 millimeters in length. Some may be invisible to the human eye, and others may be fibers reaching the length of a half centimeter. Below is an image provided to give an idea of the size of particles that were in discussion throughout the duration of the article.

A microplastic, as shown on the right, compared in size to one of the previously discussed crustaceans, as shown on the left. This comparison is provided to give a general guideline of the size of the plastics discussed in this article and blog post. Use the key provided at the top of pictures for size comparisons.

The microplastics in discussion are definitely small, but are they small enough to be labeled as negligible or harmless? The answer is no. Microplastics can block the gills of certain crustaceans, like crabs, and negatively impact ecosystems. Other animals around the globe are also susceptible to harm from these microplastics.

To be fair, larger animals will likely bypass complications caused by these microplastics. Believe it or not, humans consume a surprising amount of microplastics. One study estimates that humans consume between 39,000 and 52,000 microplastics annually. This study came about these numbers based on analyzing common food and drinks for their composition of microplastics. These numbers are surprisingly large, considering that we likely are never aware of the plastic we are consuming; if that were the case, we would just spit out our food before swallowing. Based on this, it is reasonable to assume that microplastics do not impact larger animals, such as sea turtles or big game fish. Whereas this might be true for the individual, it is not true for the ecosystems that host these animals. If their ecosystems cannot withstand the microplastic pollution, the animals themselves may be at risk.

However, there are direct, pollution-related risks to the species that may be immune to harm from microplastics. This is because microplastics are a form of pollution, but it does not act alone. All of the plastic waste around the world is not under 5 millimeters in length. A lot of waste is bigger and more prominent than the small fibers previously talked about in this blog post. The truth is there is all kinds of human waste found in our previously pristine environment. This is due to the increase in human plastic use over the past century. In the 1950’s the global plastic usage landed around 5 million tons per year. In 2020, the annual plastic usage has jumped to 330 million tons per year. The heavy usage of plastic has resulted in vast amounts of pollution.

One major example is the Great Pacific Garbage Patch, also referred to as Trash Island. The Great Pacific Garbage Patch is comprised of two massive piles of trash floating in the Northern Pacific. Whereas much of the debris is made of larger pieces of plastic, majority of it is actually comprised of degraded plastics that have turned into microplastics. These microplastics account for about 94% of the object counts of the patches. In terms of mass, however, objects larger than .5 centimeters account for 92% of the total mass. The patches are massive; scientists have estimated that the size of the patches is equivalent to twice the area of Texas. The problem here is that much of the plastic floats below the surface, and the patches are constantly moving and morphing into different shapes. These factors make it hard for scientists to estimate the size and density of the patches. These numbers are important to accurately determine, as they can lead engineers to develop more efficient ways to clean up the garbage and help restore a healthy ecosystem.

A portion of the Great Pacific Garbage Patch floats in the ocean.

Perry the Platypus’s Signature Color Isn’t Total Fantasy

 

Figure 1: Perry the Platypus, a Disney character from the show Phineas and Ferb

Recent articles from National Geographic and Science News have brought to light an interesting discovery. It was found that the fur of platypuses exhibited biofluorescence. This was not expected from researchers because very few other mammals, such as a few species of flying squirrel and a few marsupials such as opossums, are known to be fluorescent. Fluorescence works when the fur absorbs a photon at one wavelength and emits a photon at another wavelength with common emitted colors being red, green, orange, and blue. When the platypus pelt was illuminated by ultraviolet (UV) light the pelt emitted a blue-green glow similar to the color of Perry the Platypus. However, due to the UV light saturating everything with a purple hue, a yellow filter was used to produce a more “true” color to what the eye sees.

Figure 2: This picture shows what platypuses look like when illuminated with normal visible light and UV light with and without the yellow filter, and the UV reflectance.

The purpose of the biofluorescence is still unknown to researchers. Platypuses are already one of the strangest creatures alive on several counts. Not only are they one of only two mammals that lay eggs, but they also have poisonous spines on their rear legs and have the ability to sense electrical signals in water to aid in catching prey. There are several theories about why platypus fur fluoresces ranging from camouflage to a simple vestigial trait. The basis of the camouflage theory is that common predators of platypuses such as birds of prey, dingoes, crocodiles, and Murray Cod can see in the UV, and since the platypus absorbs UV light it gains camouflage. On the other hand, it could have no real function and just be an ancestral trait that was retained and has no practical use anymore. This is plausible because fluorescent fur has beenfound in all 3 major branches of mammals: monotremes (platypuses), marsupials (opossums), and placental mammals (flying squirrel). While there are still more theories such as aiding in intraspecies communication, only one real correlation that has been found, the dark. All the known cases of mammals being fluorescent occur in mammals that are active at night or in the low light time such as dusk or dawn. Since there is less known about the nocturnal world, there is a high probability that there are lots of other mammals that exhibit biofluorescence. As research continues more information on the actual cause and reason for the biofluorescence will come to light.
 

Extra Chemical Speculation:​ It is known that the species of fly squirrels fluoresce pink and platypuses fluoresce blue-green. Therefore, the chemical source of the biofluorescence is most likely different for each animal. None of the articles specified any compounds responsible for the biofluorescence, but typical organic compounds that fluoresce strongly are aromatic and/or heterocyclic compounds. It is likely that the source of biofluorescence in mammals is an unknown aromatic and/or heterocyclic compound.

Sources:

● https://www.nationalgeographic.com/animals/2020/11/glowing-platypus/#close
● https://www.sciencenews.org/article/platypus-glow-blue-green-ultraviolet-light-fluorescent-fur 

 

New Cloth Face Masks can be Disinfected by the Sun!

 Posted by Julia Munoz

In the current era of COVID-19, many people have turned to cloth face coverings. While this is good, viruses and bacteria that are stuck to the mask can be transferred off the mask when the mask is taken off. An article from ScienceDaily, discusses how ACS Applied Materials and Interfaces has developed a new cotton mask that kills 99.9999% of bacteria and viruses after only 60 minutes of daylight exposure.

Credit: Adapted from ACS Applied Materials and Interfaces 2020,

DOI:10.1021/acsami.Oc15540

Most face masks, which are made of various cloth materials, filter out nanoscale aerosol particles. These are usually released when someone coughs or sneezes. Wearing masks prevents these particles from being spread between peoples because it blocks their transmission. However, the bacteria and virus on the mask still remain contagious.  Peixin Tang, Gang Sun, Nitin Nitin and colleagues have been working on a new cotton fabric that would be able to release reactive oxygen when it was exposed to daylight, thus killing microbes attached to the cloth, while still being washable, reusable, and safe to wear.

ACS Appl. Mater. Interfaces 2020, 12, 44, 49442–49451

Publication Date:October 22, 2020 https://doi.org/10.1021/acsami.0c15540 

The group made their antimicrobial masks by attaching positively charged chains of 2-diethylaminoethyl chloride to regular cotton. Next, they dyed the modified cotton in a solution of negatively charged photosensitizer. This attaches to the DEAE chains by strong electrostatic interactions. Testing showed that the mask could be handwashed at least 10 times and constantly exposed to daylight for 7 days before losing its antimicrobial defense. 

Safer Lithium Metal Batteries

Posted by Garrett Moran

A recent article from ScienceDaily illustrates a group of engineers from Columbia University School of Engineering discovering a way to make the common lithium metal batteries not only safer, but also more efficient and longer lasting. There are countless stories of lithium batteries catching on fire and exploding. This is due to the formation of microstructures that contain non-conductive compounds on the surface of lithium metal during the battery use or recharge cycle. These undesirable microstructures stop the lithium ion transport process and cause dangerous short-circuiting within the battery which results in the battery overheating and either catching on fire or exploding.

Hazards of Li Batteries

The group of engineers discovered that the addition of alkali metals, such as potassium ions to a conventional lithium battery electrolyte, prevents lithium microstructure proliferation during the batteries use. The group achieved this by using a combination of techniques to examine the lithium metal while the additives were introduced. These techniques include microscopy, nuclear magnetic resonance and computational modeling. The article notes that when the metal was being examined while the additives were being introduced, “unique chemistry” was observed at the lithium/electrolyte interface. This unique chemistry was not specified, but the teams PI says that this addition of potassium salt to the lithium electrolyte mitigates the formation of these undesirable, non-conductive microstructures. The article also notes that this discovery differs in technique from traditional electrolyte manipulation approaches where depositing conductive polymers on the lithium metal surface was the primary focus. This discovery is one of the first to characterize the surface chemistry of lithium metal using NMR and is considered a breakthrough for new techniques using NMR and future designs of electrolytes for lithium metal.

CRISPR Cuts the Scientific Community in Two

Posted by Cole McElmurray

Much ado has been made about CRISPR, the enzyme complex that can edit and remove DNA from cells. Most recently, a team of scientists in 2017 led by Dr. Shoukhrat Mitalipov at Oregon Health and Science University published results where they used CRISPR to remove a gene that caused heart disease in human embryos. Mitalipov found that the enzyme complex did not use the sample DNA that the scientists had provided to repair the break in the DNA, but instead copied and used the healthy gene that was found elsewhere in the cell. Proponents of CRISPR say that the gene editing technology can be used to remove genetic mutations in human fetuses that would otherwise put them at risk for genetic disease and conditions, but others take the view that CRISPR is more trouble than it’s worth, as Megan Molteni reports for Wired.

Figure 1. The method by which CRISPR cuts and edits DNA. 

Opposition to Mitalipov’s findings was swift. Dr. Dieter Egli from Columbia University conducted research of his own on CRISPR. After three years, he has found evidence that seems to contradict Mitalipov’s research. Egli’s team injected CRISPR into sperm cells that were positive for a gene that causes blindness. After the sperm was used to fertilize eggs, the chromosomes of the embryos were looked at. It was found that the offending genes had been removed, but nothing had been put in their place. Large sections of missing DNA can cause major and adverse health effects to humans, such as disease, cancer, or death of the embryo, even more so than the mutated genes that CRISPR can remove.

Gene editing in human embryos also brings up major ethical concerns. Egli and his team were forced to find outside funding for their experiments because the US Congress will not fund experiments on viable human embryos, and the United States and 75 other countries ban any experiments that involve establishing a pregnancy with a genetically-modified embryo or fetus. The World Health Organization has recommended an immediate stop to experiments that would result in births of genetically modified humans. He Jiankui, the controversial figure who claims to have performed CRISPR experiments on embryos that were carried to term in China, was found guilty of a breach of medical ethics in late 2019 and sentenced to 3 years in prison.

This article is not exactly positive about science and chemistry, and seems to try to paint a picture of “mad science”. It’s meant to show the reader that sometimes scientists can go too far in their pursuit of research and progress. The article uses fear tactics by focusing on genetically modified fetuses and negative health effects that can occur from CRISPR, as well as bringing up the lurid story of He Jiankui. The article is remarkably light on actual chemistry facts. It does not even bring up that CRISPR is an enzyme complex, leading some readers to make the conclusion that it is some sort of machine or tool. While it makes mention of CRISPR “cutting” DNA, it does not mention the mechanism by which it does so. The article deliberately keeps the chemistry light in order to not bore a lay reader and to focus on the ethics of CRISPR instead of the science. 

 

Black and Blue all over: Scientists Discover a Method to Make Concrete Bruise Like a Bumped Knee.

Posted by Tim Martin 

Recently a research team from the Structural Composite Research Center at the Institute of Advanced Composite Materials, which is part of the Korean Institute of Science and Technology, has improved the mechano-sensitivity of spiropyran. spiropyran reacts to an external force that converts it into merocyanine, which appears blue in light. Before the recent development spiropyran was not sensitive enough for real life applications, for instance when injected into concrete or silicone the deformation of the parent material must be drastic for the spiropyran to visibly convert to merocyanine . However, a more sensitive polymer will not only allow for safer building materials but also the use of spiropyran in wearable sensors for artificial skin, a leap forward for the medical field. The research group enhanced spiropyran’s sensitivity to stimuli by first synthesizing a composite material and then applying a solvent mixture of spiropyran, which “ages” the molecule and makes it more fragile to force. The formed polymer showed up to a 850% improvement as compared to polymers produced through other,more traditional methods. The solvent approach also allows for the application of spiropyran by manipulating the solvent mixture based on the target material. The polymer is so sensitive it can now react to tension compression and bending, exceeding its prior applications in building materials.
 

 

Periodic Table and New Elements

 Posted by Qianhui Hua

Every field of science has its favorite anniversary.  For chemistry, there is no reason tobe celebrated beyond the origin of the periodic table. The periodic table of the elements was created 150 years ago by the Russian chemist Dmitrii Ivanovich Mendeleev.

Chemistry students have become more and more familiar with the periodic table. It enumerates the elements that make up all the earth's materials and arranges them to reveal the laws of their properties, thereby guiding the development of chemical research in theory and practice. But the periodic table of elements is not immutable. In 2016, four new elements officially became full members. I searched and understood how the periodic table gets new elements. 

Each element on the periodic table has a different number of protons. Therefore, chemists look for two known elements that they can crush together to create new elements. So far, the element with the highest atomic number discovered by humans is element 118.

To make oganesson, element 118, chemists used 20 protons of Ca and 98 protons of Cf.  A beam of ions of one element is shot at atoms of the other element. With luck, the two fuse, forming the new element. But often they don’t. And even when they do, the new element are often unstable. They can decay in mere milliseconds.

I am also very interested in its naming. These names were determined by the International Union of Pure and Applied Chemistry (IUPAC). Anyway, the IUPAC says that elements have to be named after one of five things: a scientist, a place, a mineral or substance, a descriptor of the element, or a mythological reference. Of the new elements, three are named after places and one is named after a person.
For these 4 new elements, nihonium (element 113), the name is based on the Japanese word Nippon, which is one word for Japan itself—where the element was discovered—and means “Land of the Rising Sun”. Moscovium (115), named after Moscow. Tennessine (117), named after Tennessee. Researchers at Vanderbilt University and University of Tennessee teamed up to discover this one in 2010, making it the most recently synthesized element. It’s also just the second element to be named after a U.S. state, the first being californium. Oganesson(118) is named after Yuri Oganessian, a Russian nuclear physicist.

https://www.sciencenews.org/article/physics-periodic-table-future-superheavy-elements 

https://www.sciencenews.org/article/physics-chemistry-how-periodic-table-gets-new-elements