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In the ancient Ghanian empire, a drum sounds in the distance.  Traders go to the appointed spot. The people they are trading with have already gone, leaving their goods behind them.  This is the silent trade. The commodity that wait for them unprotected is gold. What do they have to offer that would be important enough for their trading partners to trust this system so?  It’s salt. My name’s…


To a chemist, salt is what you get when positive and negative ions enter each other’s orbit. To most everyone else, salt is sodium chloride, the white crystals left over when seawater evaporates.  It’s been essential for food preservation since mankind began harvesting it in the Neolithic period. Egyptians traded cedar, glass and dye to Phoenicians who paid them primarily with salt and salted fish. The Celts were huge users of salt, growing rich by trading their salt in exchange for luxury items like wine from Greek and Roman businessmen.  Blocks of salt bound with straw, called ‘amole tchew,’ where used as currency until the early 20th century and had been since at least the 6th century. In China, bandits and rebels thrived on salt smuggling to avoid taxed.  Salt taxes and monopolies have led to protests and wars around the globe, including being a contributing factor in the French Revolution.  In colonial India, only the British government could produce and profit from the salt production conducted by Indians living on the coast. This was Gandhi and his followers marched for 23 days to protest in March 1930.  When he arrived on the coast, Gandhi deliberately violated the law by boiling a chunk of salty ocean mud. This march became known as the Salt March to Dandi, or the Salt Satyagraha. People across India began making their own salt in protest, which was an important milestone in the struggle for Indian independence.  Salt production also played a significant role in early America. The Massachusetts Bay Colony held the first patent to produce salt in the colonies and continued to produce it for the next 200 years. The Erie Canal was opened primarily to make salt transportation easier, and during the Civil War, the Union captured significant Confederate saltworks and created a temporary salt shortage in the Confederate states.  It continues to be important to the economies of many states, including Ohio, Louisiana and Texas.


The human body can’t live without sodium.  That’s why it’s been a critically commodity important throughout the world and throughout history.  Sodium is necessary for nerves to transmit impulses, for muscles, including the heart, to contract and relax, and for your body to maintain the correct fluid balance.  When sodium is in short supply, chemical and hormonal messages signal the kidneys and sweat glands to hold onto water and conserve sodium. Salt is so essential to the body that if you drink too much water it can flush it out of your system and cause fatal Hyponatremia.  Such was the case of the healthy 28 year old woman who died in 2007 when participating in a radio station contest, “Hold your wee for a Wii,” in which contestants were required to drink as much water as they could without urinating, in order to win a Nintendo video game console.  


When you get more sodium than you need, the kidneys flush out the excess by making more, or saltier, urine.  If your take in more sodium than your kidneys can get rid of, it accumulates in the fluid between cells. Water follows sodium like hippies follow the Grateful Dead, and as the volume of this fluid increases, so does the volume of your blood.  This means more work for the heart and more pressure on blood vessels. Over time, this can stiffen blood vessels, leading to high blood pressure, heart attack, stroke, or heart failure. There is also some evidence that salt can directly affect the heart, aorta, and kidneys without necessarily increasing blood pressure.  Hundreds of studies have looked at the connections between salt intake and mortality. The trouble with these studies is that virtually every one has flaws, which you get in human studies. They are too short, too small, not like the real world, or influenced by factors other than sodium. To really determine the effects of too much salt in the diet, you would need to get people who are as similar as possible in terms of health and lifestyle, ensure they eat diets as identical as possible, and follow them closely for years.  Ain’t gonna happen, cap’n. But that doesn’t mean you can disregard your doctor if she tells you to cut back on your sodium. Start by reading the labels on processed and prepared foods; the sodium level typically range from troubling to alarming. In 2011, Campbell’s Soups were sued because their “25% less sodium” tomato soup had the exact same amount of sodium as the regular variety, but it cost more. Their defense was that that was in comparison to all their soups in general, not regular tomato soup specifically, but they settled.


If humans need water and salt, why can’t we drink salt water.  The ideal salinity of blood is 9 grams of salt per 1,000 grams of water.  In medicine, fluids that have the same salinity as blood are referred to as isotonic.  When we consume too much salt, we excrete the excess in our urine to keep our bodily fluids isotonic.  Saltwater is a *hypertonic fluid with a salinity of 35. Drinking hypertonic fluids such as seawater throws the body’s coping mechanism into disarray.  Although our bodies are designed to normalize sodium and chloride concentrations, dealing with extremely high concentrations of salt in the blood is challenging.  Cell membranes are semipermeable, allowing water to pass through easily. When the salt concentration outside the cell is higher than on the inside, water moves from the inside to the outside of the cells to correct the imbalance.  You may remember from science class that the process of equalizing the concentrations of a substance on both sides of a semipermeable membrane is called osmosis.


If you drink seawater, the natural process of osmosis turns disastrous.  With the salinity of seawater being almost four times that of our bodily fluids, so much water leaves the cells to try to correct it that the cells actually shrink.  In order to regain an isotonic state, the body attempts to eliminate the excess sodium through the urine. However, at their best, human kidneys can -only produce urine that’s slightly less salty than saltwater.  So, in order to remove the excess sodium, we urinate more water than we actually drank and dehydration sets in. So, if you drink seawater, you’re actually incurring a net loss of fluids. The body tries to compensate for the fluid loss by increasing the heart rate and constricting blood vessels to maintain blood pressure and flow to vital organs.  You’re also most likely to feel nausea, weakness and even delirium. As you become more dehydrated, the coping mechanism fails. If you still don’t drink any fresh water to reverse the effects of excess sodium, the brain and other organs receive less blood, leading to coma, organ failure and eventually death. That being said, saltwater can actually come to your rescue in a survival situation.  You can mix it with your fresh water supply in a three parts fresh to one part seawater ratio to make a sort of sport drink and stretch your water supply.


To review, saltwater bad, mostly.  Speaking of reviews, we got another review through the Apple podcasts app, which always makes my day.  There’s great debate in the podcasting community about whether or not lots of positive reviews helps your show ranking, but I don’t care, I just love hearing from people who enjoy the show.  We did a get a one-star rating along the way, but the person didn’t leave a written review, so I’ll spend the rest of my life wondering what their principle complaint was. Anyway, on to the review from TeeMick, who says, “I’m a simple person with simple needs and direct input of factual information into my brain by a soothing voice with a touch of humor is really all I need.  I love this podcast!” Thanks, TeeMick. As always, credit for my radio voice goes to my mother, who was in radio in the 60’s and 70’s and whose podcast Rock History with JoChristie will debut before fall. I do get notified when there’s a new review through Apple Podcasts, but not when people review through other listening apps, so if you leave a review through your app, give us a shout.


So humans can’t drink sea water, but that’s okay, because we don’t live in the ocean.  What about animals who do? Most are what is called osmotic regulators, controlling the process of osmosis in various ways. For instance, salmon use specialized cells on their gills (called chloride cells) to excrete excess salt, allowing the fish to take in water without dehydrating.   Sea turtles secret excess salt from the salt glands behind their eyes.  They take in salt not from drinking the water but from eating jellyfish, who are mostly sea water themselves.   Sea birds *do drink salt water.  The salt moves through their blood stream into a pair of salt glands above their eyes. The densely salty fluid that results is excreted from the nostrils and runs down grooves in the bill.  Okay, but how do marine mammals not shrivel up and die from all the salinity? Scientists aren’t 100% sure, but the leading theories are that animals like dolphins and whales get the water they need as metabolic water in their food.  Some species of seals and sea lions drink seawater occasionally, but they also have access to snow to eat. Even sea ice is far less salty than sea water.


While it’s dangerously ubiquitous today, prior to industrialization, salt was extremely labor-intensive to harvest, which made salt an extremely valuable commodity.  In the Iron Age, the British evaporated salt by boiling seawater or salt spring brine in clay pots over open fires. In Jing Dynasty China people in Sichuan province excavated natural gas and used it to boil a rock salt solution.  In Rome, seawater was boiled in large lead-lined pans. Speaking of ancient Rome, you’ve probably heard that her soldiers were paid in salt, called salarium, which is where the word “salary” comes from. Just like in ep 73, “For the Last Time…” while widespread, that “fact” isn’t true, neither is the version that soldiers were given salarium argentum, or money specifically to buy their own salt.  First, the accurate bits. The English word ‘salary’ does indeed come from Latin ‘salarium,’ meaning ‘stipend, money allowance’. ‘Salarium’ does indeed appear to be linked to sal ‘salt’, via the adjective salarius ‘pertaining to salt’. There’s evidence of the facts getting muddled in dictionaries going back hundreds of years. The phrase ‘salt money’, or in Latin salarium argentum, is an invention of 18th and 19th century Latin dictionaries. The phrase was coined by dictionary-writers as their best *guess for how salarium ‘salary’ came from salarius ‘pertaining to salt’.  Actual archeological evidence of soldiers being paid in salt or having part of their wages designated for salt is thin on the ground. It also wouldn’t have been practical to pay soldiers in salt. While salt was valuable, it wasn’t like spices that were literally worth their weight in gold. A foot soldier’s wages were worth twenty Roman pounds of salt, per day. It wouldn’t work for either the soldier or the army to be paying out 600 pounds of salt to each soldier each month. What would they do with it? How would they even carry it away?


It’s been another great week for interaction with your fellow Brainiacs.  Over in the Brainiac Breakroom at url, presciently thematic for this week, Adam from Odd Dad Out podcast posted Sodium citrate is the secret ingredient to make any cheese into smooth, creamy nacho cheese sauce. Coincidentally, it’s chemical formula is Na3C6H5O7, NaCHO.  The Brainiac Breakroom is open to anyone looking for a place to share interesting tidbits they find or to get facts that don’t make it onto the main social media, as well as to talk about each week’s episode. And a big thanks to folks in the Twitterverse for RT’ing posts this week, including Eric Parfait, Jeff Vickers, Emily Prokop, Richard Enriquez, Eric Rowe, and Charles with a hammer.  And last week I finally got to be a guest on the great Historical Hotties show, which rates important people you may not have heard of on criteria like mental attractiveness and je ne sais quoi.


Humans taste saltiness thanks to epithelial sodium channels (eNaC), which are basically pores that allow sodium ions to pass into the taste receptors cells (TRCs) in the taste buds. The receptors then tell the brain that something’s salty.  Salt also makes things sweeter. Besides our mouths, our intestines are full of sugar sensors. In fact, many humans’ organs have sugar sensors and their job usually is to process glucose and insulin in the blood. However, intestinal glucose sensor (SGLT1) has another job in our mouth: it pushes glucose into the sweet taste cell when it senses the presence of sodium in the food, thus “triggering the cell to register sweetness.”  Salt also suppresses bitterness, even better than sugar does. The sodium interferes with the binding between bitter compounds and their taste cell receptors. Salt also makes food taste better by making them smell better. The ions in the salt are attracted to some of the available water in the food. So adding salt to foods makes it easier for volatile compounds — molecules that evaporate quickly and often contribute to aroma of the food — to escape into the air where you sense of smell gives your brain the bulk of information about the flavor.


Sea salt is generally more expensive than table salt because of how it’s harvested.  “Fleur de sel” (French for “flower of salt”), for example, is scraped by hand from the surface of evaporation ponds.  Sea salts are not as heavily processed as table salt, so they retain trace minerals that are usually removed in the refining process, which is why it can be white, pink, black, gray or a combination of colors, depending on where it comes from and which minerals it contains.  Some pink salts, such Himalayan salt, get their color from calcium, magnesium, potassium, copper and iron. Others contain carotene from salt-tolerant algae and are more peach-colored. Reddish-pink salts, such as Hawaiian alaea salt, have iron oxide in the form of volcanic clay.  Black salt is often just a really dark pinkish-gray color. Some foodies argue that the higher amounts of trace minerals can give sea salts a unique, earthy flavor. Others say that the taste is about the same but that their different colors and textures can add a lot to presentation.  If you’ve never had smoked salt, treat yourself, it’s wonderful.


When salt isn’t evaporated from the ocean, it’s brought up from under the earth.  Deep-shaft mining is much like mining for any other mineral. Typically, the salt exists as deposits in ancient underground seabeds, which were buried by tectonic plate shift thousands of years ago. Many salt mines use the “room and pillar” system, where shafts are sunk down to the floor of the mine, and rooms are carefully constructed by drilling, cutting and blasting between the shafts, creating a checkerboard pattern.  After the salt is removed and crushed, a conveyor belt hauls it to the surface. Most salt produced this way is used as rock salt. Table salt usually comes from solution mining. Wells are erected over salt beds and water is injected to dissolve the salt. Then the salt solution, or brine, is pumped out and taken to a plant for evaporation. Depending on the type of salt it will be, iodine and an anti-clumping agent are added to the salt.  When solution mines are located near chemical plants, they are called brine wells, and the salt is used for chemical production. After the salt is removed from a salt mine, the empty room often stores other substances, like natural gas or industrial wastes.


Salt mines are found in far-flung, exotic places like Pakistan, Chile, … Detroit.  A 114-year-old mine lies more than 1,200 feet beneath the Motor City’s roads with 100 miles of tunnels.  

Getting to the salt in 1910 proved costly, both financially and mortally.  Six men were killed during the dig, and the Detroit Salt and Manufacturing Company was bankrupted in the process. Everything had to be lowered 1,060 ft/323m into the mine, and once lowered in, it wasn’t coming back out. This included the mules.  A second tunnel was dug in 1922 so that salt could be brought up faster and larger equipment lowered in then reassembled in a machine shop in the mine. Miners ride down in a tiny elevator deeper than the Empire State Building is tall. The mine itself is a relatively clean and spacious place to work, as far as mines go. It’s not all bad: there’s no vermin, because there’s nothing to eat, and workers are even allowed to smoke.  


On the morning of November 21, 1980, a twelve-man Texaco oil rig team on Louisiana’s Lake Peigneur noticed that their drill had seized up below the surface of the shallow lake and they couldn’t free it.  There were some loud pops; their platform began to tilt toward the water and the men scrambled to the shore. 90 minute later, they $15 million worth of derrick somehow vanish into a lake that had an average depth of less than 3ft/1m.  The derrick had been 150 ft/46m tall. They had accidentally drilled into the main shaft of the Diamond Crystal salt mine, whose tunnels crisscrossed the rock under the lake. Lake water was now rushing into the mine through the rapidly expanding hole in the salt dome, with a force ten times that of a fire hydrant.  Down in the mine, fifty workers suddenly found themselves in a disaster movie, using mine carts and an agonizingly slow elevator to escape. Thankfully, they all got out alive, but the drama was just beginning for Lake Peigneur. The oilmen watched in shock as the lake became the largest man-made whirlpool in history, a swirling vortex of mud, trees, and *barges.  A tugboat, a dock, another drilling platform, a parking lot, and a big chunk of nearby Jefferson Island got sucked into the abyss. Lake Peigneur used to drain into Vermilion Bay via the Delcambre Canal, but once the lake had emptied into the mine, the canal changed direction and salt water from the Gulf of Mexico flooded into the muddy lake bed. To this day, Lake Peigneur has a brackish ecosystem very different from the way it was in 1980.  The backwards flow created a temporary 164ft/50m waterfall, the tallest in the state, and 400ft/122m geysers burst periodically from the depths as compressed air was forced out of the flooded mine shafts. The drilling companies eventually agreed to pay $45 million to the owners of the mine and other flooded local businesses, because they had been drilling in the wrong place — an engineer mistook one system of coordinates for a similar, but obviously distinctly, critically different system of coordinates.  Remind me of this if I do an episode on expensive failure.


Veering away from colossal catastrophes for a moment, I have an exciting new project to tell you about.  As if YBOF and SWSA7 weren’t enough to keep me busy (and there will be more SWS if I can squeeze into her busy summer break schedule), I’ve teamed up with three of my favorite podcast hosts to create the pilot for a new show.  Join Erik from FTW, Ryan from CT, Shawn from SYY, and myself as we take turns telling each other fascinating facts… except one of us is lying and the person who’s It only gets to ask each person one question to Spot The Lie. This pilot episode will be available as a Patreon exclusive on July 10, well before it goes out to the wider world.  Go to today to sign up for a membership as low as $2 a month to hear the first episode of Spot The Lie before anyone else. Take a look at the other tiers. In addition to early access to the regular episodes, you can get *two bonus mini episodes each month for as little as $.33 a day, less than the cheapest toll you go through, as well as voting on show topics and more.  And I’d like to thank our newest patron, Eric Rowe, who joins us all the way from New Zealand, which is some amazing and humbling reach for my little program.


Rock salt is one of the most effective substances for deicing roads when winter weather strikes. But while it makes roads safer, tons of salt end up in lakes, rivers and marshes where it poses dangers to aquatic life and the potability of water sources. It’s not doing bridges, overpasses, and any exposed metal in the road infrastructure any favors, either.  Currently, the U.S. dumps about 15 million tons each year. In some cases, the salt, silt, and other substances have been building up, layer by layer, since the 1930s. That’s why some areas are testing different substances to keep drivers safe in the winter. Some cities in Canada are now using a beet juice and salt mixture on their roads to keep them from freezing over.  The beet juice prevents roads from icing over in temperatures up to -25°C, making it more effective than using just salt brine. A beet juice mixture is also less toxic to the environment, though residents complain they don’t like the smell. One US city has used cheese brine to de-ice roads since 2009, more effectively than rock salt. Three guesses where that is and the last two don’t count.  That’s right, Wisconsin. Bergen County, New Jersey had been using pickle brine since the winter of 2014. It might not smell great (says you), but it’s cheaper and deposits less chloride into the environment than rock salt, and there’s plenty of it being discarded in homes and factories. New Jersey was pushed to use pickle brine after its 40,000-ton shipment of rock salt was held up at a port in Maine, because the vessel wasn’t flying a U.S. flag, a violation of the 1920 federal Maritime Act, which mandates that ships carrying goods between two U.S. ports must fly the American flag.  This bureaucratic tangle forced New Jersey to get creative with spare brine that turned out to be waste and cost effective. It seems many regions may have alternative chemicals on hand that can be inventively used to cut costs, eliminate waste, and protect wildlife and water and humans from the harm that is accumulating. Alaska, Russia, Hungary, and Tennessee have all used waste from their distilleries to deice roads.  


And that’s where we run out of ideas, at least for today.  We didn’t even get into salt’s significance in religion and folklore, like the Old Testament story of Lot’s wife being turned into a pillar of salt, the Finnish legend of a magic salt mill that spared slaves the burden of having to turn it all day, or the salt witch of the Nebraska plains.  I could probably do an entire episode on creation myths of how the ocean became salty, like the Russian story of a poor man who gets a magic millstone that can provide him with anything he wants. His greedy brother tricks him out of it and tells the millstone to make salt for him to sell, but doesn’t know the right words to tell the millstone to stop.  His boat sank under the weight of the salt and the millstone kept right on turning. Thanks…