On November 1st, 2017 we learned about

The origins of the artificial flavors that make your antibiotics taste like bubblegum

In 1972, Beecham Laboratories made a significant advancement in medicine that has improved the lives of millions of children around the world. They launched Amoxil, an antibiotic related to penicillin that today is often sold under its generic name, amoxicillin. The exact bacteria-busting power of Amoxil were surely great, but the real innovation may have been the sweet, vaguely-bubblegum flavor that was mixed in with the otherwise bitter liquid. By adding what tasted like a spoonful of sugar to every dose, getting kids to follow through on their course of antibiotics became easier than ever.

Battling bitterness with sweet, syrupy relief

While the weirdly chalky flavoring of amoxicillin may stand out in many people’s experience as the best part of a childhood ear infection, but it certainly was not the first time flavor was added to medicine. In the Middle Ages, when illness was believed to be an imbalance of the “four humors,” treatments were based on flavor. So if you felt sad or sour, the recommendation would be that you should avoid acidic foods and eat something sweet instead. (“I feel sad!” shouts the eight-year-old). While sugar has been linked to pain-relief, a lot of these treatments were probably only effective as placebos, and even then it seems hard to feel optimistic over the prospect of being prescribed something to restore your phlegm.

Herbal remedies offered more efficacy, but like penicillin, often taste very bitter. This bitterness was seen as a sign of the herbs potency, but it didn’t make them any more attractive to patients. Rather than have people munch plants directly, herbs were dissolved in alcohol and mixed with sugary syrups. It was nothing as exciting as the wild cherry or banana flavors you might find today, but the sweetness made medications much more palatable.

A fruit salad’s worth of synthetic flavors

By the 1800s, chemists were starting to isolate specific compounds that matched the flavors and smells of various foods. These compounds were usually esters that turned up in various contexts, like the cherry flavors that were found in byproducts of everything from alcohol distillation to coal processing. Methyl anthranilate, which in Germany was associated with orange blossoms, reminded people of Concord grapes (Vitis labrusca) in the United States. It’s now the basis for all the grape flavored candy and cough syrups on the market, even if it doesn’t taste like the Vitis vinifera grapes we snack on or make into wine. Banana flavors have a similar disconnect these days, as the isoamyl acetate that’s added to food and medicine comes from the Gros Michel banana, a cultivar that hasn’t been available since the 1950s. The flavor was included in candies in the United States before the average consumer could buy any bananas, but now it clashes with our expectations of Cavendish banana flavor.

All these flavors promised tastier candies and medicines, which became a serious problem by the 1960s. So called “candy aspirin” was apparently sweet enough to be compared to SweeTarts, a fact that was not overlooked by kids who started seeking treatment for every ailment they could think of. Many children were so drawn in by this flavor that they started eating aspirin like literal candy, and increasing aspirin poisonings by 500 percent nationwide. In response, the flavor was toned down and child safety caps were introduced to keep smaller hands away from medications.

Flavored medicines beyond bubblegum

Anyone with a young child knows that these flavored medications haven’t vanished entirely though. Dimetapp is still flavored like Concord grapes, and amoxicillin is still the strawberry-banana-cherry-cinnamon mash-up that we recognize as bubble gum. Chemistry hasn’t stopped innovating though, opening up a larger array of options than ever before, including mango, watermelon, and chocolate. If that weren’t enough, your dog can get its medicine flavored as beef, tuna, chicken pot pie, bacon, salmon, and yes, bubble gum. No reason for dogs to miss out on one of medicine’s greatest achievements, right?

Source: A Search for the Flavor of a Beloved Childhood Medicine by Julie Beck, The Atlantic

On October 11th, 2017 we learned about

What makes smoke from wildfires so bad to breathe in?

My neighborhood, while thankfully a safe distance from being actually immolated in the fires spread across northern California, is starting to look a little scary. The skies are darkened with the red tint of smoke, and trees just two blocks away are starting to be obscured by the thickening particulate. My third grader is… not taking it well. She’s nervously asking how close we are to the fires, if her aunt further north is safe, and if she should start expecting ash to start falling out of the sky, a scenario she only knows from stories about when a baby in southern California. Parental instinct leads me to try and calm her, but with at least 160,000 acres burned this week, how worried should we be about all this smoke?

Byproducts of burning plants

The smoke from forest fires has a lot of different ingredients. Trees’ and other plants’ exact combinations of cellulose, tannins, oils, waxes and more can create a wide range of chemical byproducts of a fire. Smoke from a burning forest is likely to contain carbon dioxide, carbon monoxide, water vapor, hydrocarbons, nitrogen oxides, benzene, formaldehyde, trace minerals and other particulate matter. While that may sound like a big scary list, your body can bounce back from the bigger molecules it inhales pretty well, with only temporary irritation to sensitive tissues in the eyes and respiratory tract. The items that are more worrisome are the tiny particles less than 2.5 micrometers in diameter, around 30 times thinner than a human hair. These minuscule particles can get lodged deep in your lungs, where they can cause more lasting damage to cells.

Avoiding inhalation

There are, unfortunately, a lot of health concerns with breathing in too much smoke. Older people, people with compromised hearts or lungs, and of course, growing kids, are all considered to be especially at risk when the air is too polluted. Kids with asthma are probably at the most risk, as irritation can cause their airways to close enough to completely restrict breathing, but anyone who’s lungs are either sensitive or still growing should really avoid breathing hard outdoors if at all possible. Breathing in some particulate is unavoidable— the goal is just to minimize exposure and impact.

Some folks wear dust or surgeons’ masks to try to stay safe, but most of those masks aren’t designed to block the tiny particulate that is of the most concern. Even if you do have an N-95 or P-100 respirator, it needs to fit against your face without gaps, otherwise you’ll end up sucking in particulate you were trying to filter out. Staying inside is probably a safer bet, using air conditioners to help filter the air. If that’s not an option, you may want to look for Clean Air shelters, or even climate controlled malls and businesses, as a way to avoid sucking in too much smoke.

Hazards from flaming houses

The fact that 3,500 buildings have burned down in these wildfires complicates things a bit. Houses these days are packed with a lot of plastics, which burn hot and fast, releasing more toxic and corrosive gasses like hydrogen chloride, phosgene and even hydrochloric acid. Thankfully, most of these won’t be released in high enough concentrations to affect the surrounding areas, and are more commonly issues for firefighters entering burning buildings. In those scenarios, the to big worries are carbon monoxide and cyanide, both of which are odorless, colorless and most dangerous in hot areas with restricted airflows, like a structure fire. Both chemicals restrict your body’s access and use of oxygen, and can be lethal in under ten minutes’ exposure. Again, this isn’t something you need to worry about in a smokey neighborhood downwind of a fire because concentrations each compound will probably be too low to cause that much harm, but it’s something to consider if you’re ever asked to evacuate, as staying in your home may put you and firefighters in much more risk if you need rescuing later on.

Extended influence

If all this weren’t enough, there’s a chance that wildfires are affecting you even if you can’t see the smoke. Global surveys of air quality have found that large forest fires release enough smoke to be detectable on a large scale, even beyond areas where the smoke is visible. In some cases, there are things that can be done to try to mitigate the impact of forest fires, from direct prevention to reducing carbon emissions that raise the world’s temperatures and make fires more likely in the first place.

For now, everyone’s rubbing their eyes, doing a bit more sneezing, and hoping that the fires can be contained before things get too much worse. If waiting things out feels too passive,  making donations to the people whose lives have been more directly uprooted by the fires has felt helpful as well.

Source: Wildfire Smoke: A Guide for Public Health Officials by Harriet Ammann, Robert Blaisdell, Michael Lipsett, et al., Environmental Protection Agency

On September 28th, 2017 we learned about

Test authenticating paintings’ particular yellow pigment turns up with problems of its own

By the time you graduate from that first batch of eight crayons, you start to learn that just how much variability there is between one hue and it’s closest cousins. Despite similar naming conventions, you wouldn’t arbitrarily substitute Strawberry for Raspberry Red. These differences can even persist in what is supposedly the same color, depending on its formulation. A pigment known as Indian yellow is so particular it’s origins have become the stuff of slightly unbelievable legend. More importantly, the pigment has also become the center of controversy in identifying the dates and possible authenticity of many famous paintings from the early 1900s.

One of the best places to see Indian yellow is in the sunsets painted by Joseph Mallord William Turner. The impressive but not overly-saturated yellow of the late afternoon sun in Caernarvon Castle, for instance, is an example of a pigment that originally became popular with European painters back in the 14th century. Supposedly, it was produced only in Bihar province in India, where cows were fed only mango leaves. The cows’ urine was then collected and dried so that the remaining concentrate could be mixed with oil, creating the subtle hue that many artists desired. This method of production then continued until the early 1900s when it was halted out of concern for the cows, although that also happens to be around the same time when synthetic dyes and pigments were becoming more widely available.

Testing paint with the wrong test

Whether or not it was ever in a cow’s bladder, true Indian yellow is a magnesium salt of euxanthic acid. Its synthetic competitors were generally azo-based dyes, including tartrazine, a compound found in food coloring today. The synthetic, “fake” Indian yellow may have looked the part to most observers, but it was quite different on a molecular scale. This has proved useful to historians and curators, as the type of yellow could be used to prove when a particular painting was created (or at least altered or repaired.) By comparing the chemical signature of a euxanthic acid against an unknown painting, a researcher could tell if it was painted before or after the early 1900s. Theoretically.

This system was recently discovered to have a major flaw. People’s understanding of the two different paints was correct, but the “real” Indian yellow that they were often comparing new samples against was discovered to respond to measurements just like “fake” tartrazine pigments did. Essentially, people were checking for forged or altered paintings by comparing them to another “fake.” While figuring out how this mix-up occurred in the first place will take some time, curators are now looking to double check the paintings already in their collections. Fortunately, only Indian yellow made with euxanthic acid will fluoresce under ultraviolet blacklights. This low-cost test promises a quick alternative method of authentication, at least until a new spectral analysis standard can be established.

Source: The hunt for Indian yellow by Raychelle Burks, Chemistry World

On September 27th, 2017 we learned about

How chemistry lets us put pumpkin, orange or butter flavors in practically any food

It’s fall, which means every other item at my local Trader Joe’s now has pumpkin in it. Or the essence of pumpkin, at least. You know, that lovely cis-3-Hexen-1-ol (C6H12O) that your nose senses after you slice into a big, orange gourd to carve a jack-o-lantern. Or the always nostalgic dash of sabinene (C10H16) that you taste in a good pumpkin pie, and naturally, pumpkin tortilla chips, which are also a thing… These products probably do have their fair share of pumpkin puree, but sometimes smushed pumpkin isn’t even what we really expect to taste when offered a “pumpkin flavor” product. This isn’t really a problem either way, since really what’s going on pumpkin and other flavors is just some refined manipulation of how we perceive flavor in the first place. And probably sugar.

Compounds that are convincing to your nose and brain

You might not have anything labeled cis-3-Hexen-1-ol on your spice rack, but it’s actually one of the various compounds you’re likely to notice when you cut into a ripe pumpkin. Alongside a few other alcohols and aldehydes, the right ratios of these molecules hitting the right smell receptors in your nose will get your brain working to identify what is causing the aroma. With a pumpkin in front of you, that particular blend gets labeled as “fresh pumpkin smell” in your memory, although none of those compounds are terribly unique. When you taste (and smell) the food you eat, your brain is simply referencing memories of other times you’ve had those particular smell receptors get activated in some particular proportion.

Now, cis-3-Hexen-1-ol is a decently large molecule, but only one portion of it is needed to activate a smell receptor. Rather than have a receptor that can accommodate the entire molecule at once, your nose only really cares about the OH at the end. This is very convenient for chemists, who can attach that smell signifier to other compounds that may be more stable, cheaper or somehow easier to work with than what the pumpkins make themselves. It’s a concept that gets used in tons of different foods, with these artificial flavors often being mixed back into the foods they originated in.

Close control over foods’ flavors

As food production shifted to industrial scales in the early 20th century, manufacturers needed food that could survive longer in transport and on shelves, bring down costs, and also taste consistent from one helping to the next. As with pumpkins, oranges have had their chemistry parsed to see which molecules trigger the experience of “orange flavor,” so that it could be used in other products, as well as orange juice itself. By adding something like ethyl butyrate to orange juice, manufactures can be sure that a crop of bland oranges won’t tank their sales for a season. Similarly, diacetyl was added to products to give them a buttery taste, but the flavor association was so successful that creameries now spike actual butter with the compound, so that butter tastes more like what our brains think of as butter.

In the case of the deluge of seasonal pumpkin products, we also have to accept that we’re not sure what we want to taste. While cis-3-Hexen-1-ol is found in actual pumpkins, that’s not a smell you’re really looking for in your coffee or pumpkin biscotti (which is also a thing.) In those cases, the target flavor is actually pumpkin pie, which is why recipes also include sabinene for nutmeg, eugenol for cloves, and cinnamaldehyde for cinnamon. As ubiquitous as this now seems, it’s not an easy batch of flavors to get right since one person’s perfect pie might not match the expectations of someone else. This led Jelly Belly candies to even temporarily abandon their attempt at pumpkin pie flavor, at least until they embraced the variability inherent in the task by billing the candies as their “family’s” own recipe. Fortunately for manufacturers, sugar helps smooth things out considerably, as it’s certainly a flavor that our brains remember as “yummy.”

Source: The Absurd History of Artificial Flavors by Alison Herman, First We Feast

On September 26th, 2017 we learned about

Fuel cells may soon be powered by hydrogen harvested from people’s pee

As hydrogen fuel cells become a more common way to power our world, the idea of filling up your tank may take on a few new connotations. These power plants capture energy from the reaction of hydrogen bonding with oxygen, and while amazingly clean, they still require some raw materials on hand to function. Hydrogen is abundant in our universe, and oxygen is literally floating in front of your face right now, but capturing these ingredients in a form that’s usable isn’t always easy. The U.S. Army Research Laboratory has been working on how to simplify this supply chain, and may have found a very convenient source of hydrogen in the form of soldiers’ pee.

Making use of human urine wasn’t the project’s original point of interest, but has turned out to be so efficient that researchers can’t ignore its promise. They had originally been working with water and a nano-galvanic aluminum powder, which, when added to water would cause a reaction where one of the products was pure hydrogen. A few different water-based liquids were tested, and pee was found to perform twice as well straight H2O. Researchers haven’t narrowed down the secret to urine’s success, but think may be tied to the higher acidity and presence of electrolytes.

Portable power sources

If researchers do figure out why pee is such a good hydrogen producer, they’re not looking to alter that side of the formula. While the aluminum-based powder may still be refined, the goal of this project was to enable soldiers to generate power in remote locations. Researchers estimate that as little as two pounds of aluminum powder could yield enough hydrogen to produce 220 kilowatts of electricity, which is enough to fully charge up nine Nissan Leafs. As long as carrying the powder isn’t a problem, soldiers could then provide the necessary hydrogen by recycling other fluids, including the pee a healthy body creates anyway. To really close the loop on this supply chain, soldiers could then drink the clean water a fuel cell produces as a byproduct, getting them ready to top off their generators later on.

My kids said: Ew. That’s gross! Wouldn’t the water be like pee water?

Nope. The urea and other stronger smelling ingredients in the pee would be totally left behind in this processes first step. The water molecules from the pee would be effectively destroyed before even entering the fuel cell, and so the water byproduct at the end wold be pure water with no adulterants. It’d be safe to drink, although you presumably do have a dried out pile of urine ingredients after extracting the hydrogen from it.

Source: Army scientists discover power in urine by David McNally, United States Army Research Laboratory

On August 27th, 2017 we learned about

Lasers and polystyrene prove that outer planets can produce diamonds

Giving new meaning to the term “Ice Giants,” researchers have confirmed that Uranus and Neptune are likely producing massive diamonds on a regular basis. The frigid planets may be loaded with frozen hydrogen, helium, water and ammonia, but atmospheric conditions can still scrape together enough carbon, heat and pressure to create millions of carats of solid diamonds. Aside from further embarrassing the lie that diamonds are a rarity, understanding how the outer planets make their bling may help us analyze new exoplanets in other solar systems.

The key ingredients for the formation of a diamond are carbon, heat and pressure. The carbon should be as homogeneous as possible, lest you end up with a muddled mess of coal containing everything from oxygen to arsenic that ruins the diamond’s perfect structure. The heat and pressure need to be applied together, crushing the carbon atoms into a nice, tetrahedral lattice. On Earth, these conditions are most likely to be met deep in the ground, or possibly in a lab in California.

In the SLAC National Accelerator Laboratory, researchers used a laser to recreate some of the conditions we know exist within Uranus and Neptune, with the expectation that it would be enough to create some diamonds. The source material was a piece of polystyrene, as the plastic’s carbon and hydrogen are a good proxy for the methane found on the ice giants. With a good zap from an optical laser, overlapping shock waves were created in the polystyrene, briefly creating conditions hotter than 8,500° Fahrenheit with 145,038 pounds of pressure per square inch.

Dainty diamonds, distant worlds

This intense moment was barely a moment though. The shock waves existed so briefly that an x-ray laser operating on a femtosecond timescale was needed to document the process. The resulting diamonds were tiny too, reaching only a few nanometers across. However, scaling this process up to the size of a planet like Uranus or Neptune should give a much more dazzling result, with massive diamonds being created in the planets’ liquid mantles before settling near their rocky cores.

With these calculations in hand, scientists hope to improve our estimates about exoplanets with similar compositions. Beyond the radius and mass that we can now estimate, knowing what reactions and activity are happening in a distant planet’s interior would help explain everything from their weather patterns to the exact coloration of their atmospheres.

Source: The Forecast on Neptune? Diamond Rain by Nathaniel Scharping, D-brief

On August 13th, 2017 we learned about

Cow pie biogases now provide fuel for farm’s giant feed truck

The average dairy cow produces around 40,000 pounds of manure a year, most of which doesn’t just disappear into thin air. As a cow pie decomposes, some of that solid waste does become a gas, the most notorious of which is methane. Even though you can’t see all that CH4, it makes a big difference to the world since it traps 23 times more heat in the atmosphere than carbon dioxide. Fortunately, methane doesn’t need to simply waft away, and farms are now using their cow poop to power everything from buildings to the very feed trucks that carry food to cows in the first place.

Prepping poop for generating power

Unfortunately, you can’t just scoop some poop into a gas tank and be on your way. Cow poop is made of a variety of materials which need to be separated so they can be used more efficiently, not totally unlike the refinement processes for crude oil. To make the most of their manure, farms have to invest in a huge container called a digester. The digester helps maintain an optimal temperature for poop to break down, and conveniently contains the unpleasant “barnyard aromas” at the same time. The products of digestion are fibrous materials that can be used as cow bedding or other products, potent liquid fertilizer, and assorted “biogases,” including methane.

Methane burns easily, which is why it’s the primary component of natural gas. Burned in combustion generator, plenty of electricity can be harvested to power farms, trucks, and even surrounding communities. Again, the methane doesn’t simply vanish into thin air though, and burning methane does create carbon dioxide as one of it’s by-products. Still, since carbon dioxide isn’t as potent a greenhouse gas as methane, most people consider this a win. It doesn’t hurt if farms can be more self-sustaining either.

Dung-fueled driving

The amount of power than can be generated from reused cow poop is significant enough that many farms are looking to expand their capacity. Farmers that have made the investment to set up one digester are often interested in setting up a second. The Straus Family Creamery in California took a different approach, and invested in a lengthy retrofitting project with their International Harvester feed truck. After eight years of work, they converted the diesel truck into a zero-emissions electric vehicle so that it could be powered by their poop-fueled generator. Apparently the creamery feels their cows’ poop can provide even more, and they plan to power a delivery truck with methane-produced electricity in the near future.

Source: Poop-Powered Electric Feed Truck Debuts at Northern California Creamery by Tiffany Camhi, The California Report

On July 19th, 2017 we learned about

Ice cream isn’t gelato because of additional air, fat and cold

My third-grader said she has a preference for ice cream over gelato, which is interesting since they’re nearly the same mix of sugar, fat, ice and air. Gelato actually means ice cream in Italy, but the rise of what some people call “American ice cream” has prompted some examination of the differences between the two desserts, even beyond third-graders. The same flavoring may seem to taste a bit different, despite similar ingredients. The key is how the frozen treats are prepared, and the specific balance of fat, temperature and ice you’ll find in each.

Ice fixed with fat

At their core, ice cream and gelato both share the same basic formula. By volume, each sugary scoop is mostly ice, but that ice has been prepared to keep it from behaving like a hard, solid block in your mouth. Through a process known as emulsification, the ice crystals are kept as small and separated as possible so that no single piece of ice stands out. They’re suspended between milk fat, sugar and in the case of custard-based ice creams, egg yolk proteins which makes for a cold but smooth and creamy texture, rather than something as hard and crunchy as a snow cone.

Getting the fat and ice balance right is a big part of what makes ice cream delicious. Richer ice creams tend to have more fat, and products labeled “ice cream” in the United States are even required to be at least ten percent fat. Gelato, on the other hand, is made with more milk than cream, and so it has less fat per serving.

Inflated with air

To further soften the fat and ice, air is also whipped into both ice cream and gelato. Ice cream has air whipped in more vigorously, leaving more air bubbles trapped inside the fat, ice and sugar and increasing the volume of the finished product. That change in volume due to air is called overrun, and it can vary a lot depending on the recipe being used. Premium ice creams tend to avoid adding more than 25 percent overrun since it means less fat, sugar and flavor per scoop, but cheaper ice creams really fluffs things up. At the far end of the spectrum, soft-serve ice cream can have 100 percent overrun, making for a very spongy dessert that can melt pretty quickly.

Again, gelato follows the same formula, but in different amounts. Gelato overrun amounts are generally much lower, as it’s churned more slowly than other ice creams. The result is a denser scoop that can pack a lot of flavorings (versus air) into each bite. With less cream and less air, it seems like gelato should be getting closer to just freezing into a single block of ice, but that’s where temperature comes into play.

Robust refrigeration

Ice cream is produced and stored at lower temperatures than gelato. Commercial ice cream is sometimes churned in drums cooled with ammonia to -22° Fahrenheit, which helps keep the emulsified ice from moving around too much. It’s generally served at around 10° Fahrenheit so that it’s cold enough be structurally stable while starting to soften enough to let the tasty fats and sugars interact with your tongue.

Gelato avoids freezing up by being churned and served at higher temperatures. Even though there’s less fat, no egg yolks and less air to keep the ice from congealing, the warmer temperatures help maintain the pleasant, creamy texture. It can get soupy pretty quickly, although both gelato and ice cream recipes often include various gums or gelatin to help keep the structure stabilized.

Sugar and salts are of course two more important ingredients for these frozen treats, but they vary so much by recipe that they’re not useful to differentiate ice cream from gelato. Both help keep ice crystals separated while lowering the water’s initial freezing point, but the amount of sweet or salty is usually more about the desired taste rather than the defining the exact amount of creaminess. Perhaps the sweetness does play another role though, which is to add to one’s motivation to finish dessert before finding out when their ice cream or gelato is going to fall apart.

Source: What's the Difference Between Gelato and Ice Cream? by Max Falkowitz, Serious Eats

On July 16th, 2017 we learned about

High-speed ions make Comet 67P a surprising source of molecular oxygen

There’s a lot of oxygen in space, but not in a form you can breath. Thanks to the respiration of plants on Earth, our bodies have evolved to use O2, known as molecular oxygen, to pull off our own metabolic processes. Outside of our delightful atmosphere, the most likely place to find oxygen in the cosmos is bonded to other elements like hydrogen and carbon. O2 isn’t distributed equally around the universe, and scientists were starting to look at it as a marker of an Earth-like, habitual planet. However, newly released data from the Comet 67P/Churyumov-Gerasimenko is making us reconsider this most precious molecule yet again.

When the Rosetta spacecraft first reported molecular oxygen near Comet 67P, the assumption was that it was being released from deep within the comet’s core. As the comet got closer to the Sun, it warmed up, melting ice and loosening up, releasing gases that were normally frozen solid, including O2. This O2 would have then been some of our solar system’s original supply of oxygen, created 4.6 billion years ago alongside our Sun. However, unrelated research serendipitously suggested that O2 might not created as infrequently as previously assumed.

Synthesizing O2 with solar wind

Konstantinos Giapis looked at the data from the Rosetta spacecraft not from a geologists perspective, but from his experience as a chemical engineer developing microprocessors. His work involved studying the interactions between high-powered ions and semiconductor surfaces, usually for the purpose of improving memory components in computers. Giapis happened to be curious about this data from space, and recognized that the oxygen on Comet 67P was emerging in similar conditions to those he usually created in his lab.

The emerging hypothesis is that the molecular oxygen seen wafting off of Comet 67P isn’t from the birth of the solar system, and is instead being created as the comet orbits the Sun. Water molecules from ice inside the comet are indeed being released, but ions from the Sun, collectively known as solar wind, are actually breaking those water molecules apart. More oxygen is also being freed from rust and sand on the outside of the comet, and these loose atoms can then bond into new O2.

If this is confirmed, it’s good to know but certainly complicates our model of the universe. There had been hope that O2 could be an indicator of life on distant exoplanets, but knowing that it these molecules can be made with debris and the ions means that it’s not always going to be a sign of respiration. O2 is still rather unusual, but we now know there are more ways to get a hold of some if you don’t have any plants around.

Source: Comet 67P Found to Be Producing Its Own Oxygen in Deep Space by Nancy Atkinson, Seeker

On July 6th, 2017 we learned about

Testing tar-based water bottles for the transmission of dangerous toxins

Keeping potable water portable has been one of humanity’s big challenges. The different flavors and smells of water are thanks to all the different materials water can pick up and carry from its containers, from stream beds to lead pipes. Some containers are more concerning than others, including some of our favorite plastics of today. As those bottles break down, small amounts of molecules like BPAs can end up in your water. As much as people are trying to avoid these contaminants today, they’re rather benign compared to the first “plastic” water bottles, which were made of something regarded as “nature’s asphalt.”

Bottled in bitumen

Bitumen is a form of petroleum that can be functionally solid at room temperature, but usually oozes like a very viscous liquid over long amounts of time. It’s composed of a variety of compounds, and can be found in a variety of natural settings, such as sandstone, bubbling up under lakes, or for the paleontologists, the La Brea Tar Pits in Los Angeles. Native American tribes living on islands of the coast of Southern California, collectively known as the Chumash, also found bitumen washing up on their beaches. The little balls of tar seep out of fissures under the ocean, and with a little work, the Chumash peoples realized that bitumen could also seal water into a container better than ceramics or skins.

The recipe for a Chumash water bottles required plant-fiber nets, pitch from trees, an abalone shell and of course a lot of bitumen. The netting was a framework to make the overall shape, which was generally bulbous with a narrow spout on the top. The shell helped provide some initial structure at the bottom, and the rest was made by slathering melted bitumen and pitch along the netting. It’s a sticky, smokey process, but researchers recently recreated it so that they could test exactly how many toxins these bitumen bottles may have been.

Safe to sip and sup?

The carefully recreated bottles were left to hold water for two months to simulate the passage of time, then tested. Mass spectrometry found that the water had picked up naphthalene, phenanthrene, and acenaphthalene, all of which can be toxic if ingested. Tests were also conducted with olive oil instead of water in order to simulate contact with other foods, since there is evidence that Chumash people ate meats and fish off bitumen-based bowls or plates. The olive oil picked up more toxins, but it may not be a perfect proxy for what the Chumash were actually eating. In the end, the most dangerous component in all these products was the smoke made during their production. That wouldn’t have harmed as many people, but anyone regularly making bitumen water bottles likely paid a price to do so.

These investigations weren’t just interested in water bottle technology. Skeletons of Chumash people from around 5,000 years ago turn up with an unusual number of health problems, including poor bone quality, smaller skulls, and bad teeth. The data from the recreated bitumen water bottles don’t fully explain these health problems, although it’s a tough connection to prove at this point. Most studies of toxicity are based around people that still have enough flesh to damage, and so there’s not a lot of information if you want to know how naphthalene might affect bones over a lifetime. Still, the amount of toxins leached into the water, oil and of course, smoke, do suggest that these water bottles contributed to health problems at a minimum.

Source: Plastic Water Bottles Might Have Poisoned Ancient Californians by Nick Stockton, Wired