It’s been a week since my last post and I’m still thinking about salt. Salt mines. Road salt. Sea salt. Waking up in the middle of night and drinking several glasses of water because dinner was too salty. (You also can’t make a batch of lactofermented pickles without some salt.)
I remember learning in 6th grade social studies that salt was a major trade item in the kingdoms of ancient Africa. Check out this National Geographic video from Taoudenni, Mali of salt mining and transportation, similar to the process that took place hundreds of years ago. The workers cut slabs of salt from the beds, which traders load onto camel caravans to transport across the desert to Timbuktu.
The Taoudenni salt deposits are relatively recent Holocene (geologically speaking). Lakes covered this area about 9000-4000 years ago. As the climate changed, the lakes eventually evaporated, leaving salt deposits behind.
One of the challenges of producing modern sea salt is the presence of microplastics left behind by evaporating seawater. Karami et al (2017) tested 17 commercially produced sea salts from 8 countries for microplastic particles. These tiny bits of plastic wash out in our laundry wastewater, or photodegrade from larger pieces of plastic floating around in the ocean. Eventually, ocean circulation brings those tiny plastic bits to even remote locations (like the very bottom of the ocean). From the report, “Due to their low density and slow degradation, plastics are becoming the chief cross-border contaminant that often travels far from their original source. Hence, [microplastics] found in the salt samples of one country could have been produced by another country thousands of miles away. ”
For more about microplastics pollution, check out my posts here and here.
This morning, I woke up to the rumble of salt trucks and snow plows. Southeast Michigan is experiencing the first significant snowfall of the season this week. The mood is varied (depending on who you ask) with emotions of delight, annoyance and resigned acceptance (sometimes all mixed together).
While the kid part of my personality checks the school closings for a snow day first thing (810 today in Metro Detroit!), the grownup part (with the driver’s license) is very grateful for my car’s snow tires, the snow removal crews and copious amounts of rock salt sprinkled on the roads. Salt, when added to the wintry roads, keeps the slush and melted snow from re-freezing by depressing the freezing point of water. When salt molecules dissolve in a film of liquid water on top of ice, these dissolved substances alter the way that water molecules can line up to freeze. It takes a lower temperature to freeze water with stuff dissolved in it.
These salt layers are what remains of a shallow saltwater sea that once covered this area around 410 million years ago. This ancient “Great Lakes region” (which is a little confusing, because the Great Lakes wouldn’t form for another 400 million plus years), was located near the equator. Coral reefs allowed some water in, but limited exchange with the larger ocean. The seawater got saltier and saltier as the water evaporated in this hot climate.
Eventually, the salt (and other minerals) would precipitate in layers from the super salty water that sank to the sea bottom. By the end of the Silurian period (390 mya), this inland sea completely dried up, leaving only the salt deposits behind. (I highly recommend checking out MSU Prof. Randall J. Schaetzl’s online resources about Great Lakes geology.)
I like to think about how the salt spread on the local roads (even though it contributes to potholes, cars rusting and water pollution) is a connection in deep time to sunny days on an ancient sea. Right here, in this place (but not this latitude), now and 400 million years ago.
In case you missed it, this past Tuesday, December 5th, was World Soil Day! (I realize I commemorated it belatedly last year, too.) Maybe soil is a little like the heroine of “Sixteen Candles,” ignored on her birthday while chaos rages all around her. It’s easy to take soil for granted, even as it stands as this firmament beneath our feet. But don’t worry, soil, whether you’re caught in our fingernails or nitrogenating below a blanket of snow, plenty of folks are thinking about how awesome you are.
The amazing folks at the Land Institute in Salina, KS are doing some pretty nifty research on creating prairie agricultural ecosystems, including the development of perennial crops. These perennials plants help stash more soil organic matter conventional agriculture with annual plants. One of these perennial grains they’ve developed, Kernza, is now available fermented into beer!
We love you, soil. We might call you “dirt” sometimes, but we mean it fondly.
I would be remiss if I failed to mention my interest in the topic (as a clothes-wearer, water-drinker and eater-of-food) started with a series on articles on plastic pollution by science writer Lola Gayle at STEAM Register and Science Crush (Read some of them here, here and here. ) Thanks, Lola!
In addition, outdoor retailers like Patagonia and environmental advocacy organizations such as The Story of Stuff have been generating awareness about how wearing and washing synthetic fabrics can contribute to this pollution stream.
Check out some citizen scientists sampling microfibers from Puget Sound aboard the schooner Adventuress:
But as a science-educator and a concerned citizen, being informed about the problem isn’t enough. I also want to know how to take action. What can we (both as individuals and society) do to both reduce microplastic pollution and mitigate its effects?
One reader suggested that nudity (ignoring for a moment the issues of frostbite and indecency laws) could solve the problem of washing clothing made from synthetic fabric (It seriously reduces the volume of dirty laundry!) This suggestion would also possibly improve one’s Vitamin D levels by increasing overall skin exposure to sunlight.
Other suggestions have included only purchasing clothing containing natural fibers (i.e. cotton, wool, silk, hemp), whose fibers will biodegrade more readily when discharged with waste water.
But what if you already own a lot of synthetic-fiber based clothing and want to keep wearing it? These fibers seem to be in everything, from yoga pants to t-shirts to wool-blend socks.
1. Reducing washing frequency and intensity.
This cat won’t let you wash his fleece!
Suggestions from Patagonia and researchers at UC-Santa Barbara include washing your fleece outerwear less frequently, and using a front loading washing machine.
Any machine washing will wear down the fiber and cause micro-bits to break off. If you wear your stuff a little schmutzy (as any TEVA educator will attest), you don’t have to wash it as often (ergo, reducing breakage potential in washing machine).
If you use a front loading machine (vs. a top loading machine) it lowers the intensity of the laundry agitation, reducing impact on the fabric and breakage of fibers.
The folks at Plastics Pollution Coalition also add: Washing in cold water (is less tough on the fibers), using liquid detergent instead of powder (ditto) and drying on slower speeds (less impact during tumbling.)
2. Improved filtration of wash water.
Another strategy is improving filtration of the washing machine water to remove as much of the microfibers as possible before the effluent is released down the drain.
Some filters, like this one, are installed on the washing machine itself to catch microfibers from the water. The filters must be periodically cleaned out and have the microfiber clogs disposed of in the trash. These were originally designed with septic systems in mind, because plastic microfibers don’t break down in a septic system’s biological digestion process and clog up equipment.
If you can’t modify your washing machine, the folks at GuppyFriend have developed a wash bag (like a lingerie bag) that will catch synthetic fibers coming off your clothes. Users put laundry in the bag before putting it in the machine. Then after you remove your laundry, you clean out the bag after each wash and dispose of fibers in the trash. GuppyFriend bags started with a crowdfunding campaign, and do not yet appear to be available to the general public for purchase. Will keep you posted.
Since we’ve been washing synthetic fabrics for awhile, a lot of plastic microfibers have ended up in our bodies of water, as well as in our farm fields (fertilizers made from treated municipal sewage sludge may contain laundry-borne plastic microfibers). The plastic microfibers are out there in the world.
Some organisms may be adapting to consuming and breaking down plastic fibers in our soil and water. For example, researchers have discovered that mealworms (darkling beetle larvae) appear to be able to eat styrofoam (polystyrene) due the special Exiguobacterium sp. of bacteria that live in their digestive tract.
A team in Japan discovered a species of bacteria, Ideonella sakainesis, in wastewater and sediment samples at a recycling plant. These bacteria can eat a thin film of polyethelene (PET)- the same plastic used in water bottles and polyester fleece- given enough time and the proper temperature.
It is still too early to tell if any of these organisms (or others like them) will be able to tackle the massive amount of plastics humans have dumped into the environment. The fact that these critters exist gives me hope that microfibers may not be floating around forever. However, it is still better to try to keep microplastics out of water in the first place.
Or my love affair with synthetic fabric and shed microplastic fibers.
It’s a laundry day again (an occasion usually determined by running out of clean socks and/or underwear). I dutifully sort out my pile of dirty garments into hot, warm and cold washes. Bras and fine fabrics on delicate cycle. Add some bleach to my gunk-stained kitchen towels.
Here is a cute picture of a toddler captivated by a washing machine:
Normally, my focus is on whether or not the washing machine in my apartment building is being used by another resident. (It’s not – Check!) But today, I’m thinking about washing machine waste water, specifically the laundry fuzz in the water that shakes loose during the washing cycle, and where it ultimately ends up.
This is not the first time I have been concerned about the issue of wastewater treatment.
This is the cover of my 7th grade research paper on wastewater treatment, circa 1994. Found while cleaning out my childhood bedroom. The colored things are supposed to be pipes.
Back to laundry. So from my particular washing machine usage, the waste water (which often contains little fuzzy bits of lint that come off of synthetic fabric in the wash) goes to the Downriver Wastewater Treatment Plant, which discharges treated effluent into the Detroit River. The Detroit River continues flowing into Lake Erie, and then Lake Erie water continues to flow throughout the Great Lakes.
That water flowing from my washing machine to River to Great Lakes still contains tiny, tiny particles of plastic fibers shed from the fuzz of my polyester fleece sweaters and other synthetic fabrics. Hoffman & Hittinger model this flow of microplastics into the Great Lakes in the December 2016 Marine Pollution Bulletin. (Note: Not all the microplastics come from washing machine discharge.)
These microscopic plastic fibers might look something like this:
The problem with these synthetic microscopic fibers is that they’re … plastic. They’re really, really small, so they are impossible to remove from the water after the fact. They don’t biodegrade in the water (though they might break down into even smaller particles.) These fibers can absorb (and concentrate) other pollutants that are present in the water. And then these plastic fibers get eaten by plankton, and then work their way up the food chain into the bodies of fish and other wildlife, including humans.
As an environmental educator, most of my “outdoor” clothing (i.e. Teva Pants, long underwear, and outer layers, including socks) contain synthetic fibers. Every time I come out of the garden or woods to wash my mud-caked clothes, I’m contributing to this pollution problem.
There are few things more miserable, albeit non-deadly, than a cold. I was sitting on my couch, nostrils taped open with a “Breathe right” strip, my achy body wrapped in an afghan. By then, I was feeling quite sorry for myself, blowing my nose, and tossing a heap of crumpled tissues into the waste basket.
As I cradled a steaming cup of tea in my hands, my phone rang. I glanced at the caller id.It was my Dad. I picked it up.
“Hello?” I hoarsely croaked into the receiver.
“Are you sick again?” My dad asked. “Haven’t you been taking Vitamin D?”
“I’ve been taking 2000 IU a day!” I protested.
“Hmmm,” he said. “Maybe you should take more.”
Vitamin D is probably one of the most underratedly awesome contributors to human health and well-being. It helps build bones, and regulate the immune system. (Aranow, 2011.) Vitamin D may also help prevent heart disease and play a role in preventing certain cancers. (Harvard School of Public Health). As a human living in a northern latitude (approx 42 deg N) during the wintertime, I am the first to admit that I am not up to synthesizing all my own Vitamin D from sunlight and/or food consumption.
Humans synthesize Vitamin D from sunlight when UVB rays hitting skin convert precursor 7-dehydrocholesterol into Vitamin D3. Vitamin D3 travels to the liver and kidneys, to be come an active form of Vitamin D (Source: Harvard Medical School, 2009)
One of the ways in which Vitamin D may boost the immune system is by activating t cells, the guardians of the immune system that spring into action when they detect “non-self” invaders (i.e. pathogens) in the body. Per 2010 research paper at the University of Copehagen, after t cells detect traces of foreign material, they must become “activated” in order to become sensitized and effective fight that specific germ. T cells send out a chemical signal that triggers production of the VDR protein. VDR brings Vitamin D into the t cell, “activating it to hunt down and bind to pathogens. TL;DR: Not enough Vitamin D? T cells will not be marshalled as quickly to fight nasty germs.
So what’s a winter-bound, higher-latitude-located human to do? I could ingest more food sources of Vitamin D, like the injured Viking chugging fish oil in the extremely entertaining historic skiing movie, The Last King. Getting naked outdoors in subfreezing temperatures for maximal epidermal sun exposure is a no-go. (Frostbite, possible arrest due to violation of public decency statues.) Also, my relatively high latitude geographic location (Michigan!) in winter would reduce the incident angle (and Vit D synthesizing effectiveness) of sun exposure.
(It probably doesn’t help that my melanin-deficient skin’s causes me to cover up even in summer. This is what I usually look like when I plan to spend any time outside even in warmer months. )
It looks like the Vitamin D tablets are my new best friends. P.S. Cold symptoms subsided after a weekend with tea, soup and self-pity. Also, probably Vitamin D.
However, here at the Protopian Pickle Jar, I’m offering some reasons for blog-reading, clothes-wearing, oxygen-breathing, food-eating humans to get excited about soils!
Everything We Eat and Everything We Wear!
In TEVA, we taught the kids a chant: “Sun, Soil, Water, Air! Everything we eat and everything we wear!” Then, we challenged them to come up with an item that did not derive its existence from any of those things. (It’s rhyming version of the adage I learned in my undergrad earth science classes, “If it’s not grown, it’s mined.”) No matter what they came up with (plastic dinosaurs, fuzzy socks, water bottles) we were able to trace back its origin to a natural resource.
Every piece of clothing I’m wearing (including dyes, zippers, elastics and snaps)from my cotton underwear to my wool socks to my poly-blend shirt ultimately began with the soil. (Synthetics made from petroleum-based chemicals are mined from oil, which develops from long-dead marine algae, a kind of deposit of ancient solar energy.) Every item of food I eat – fruit, veggies, grains, meat, dairy, mineral supplements- began with the soil.* (Even food that comes from marine ecosystems is still linked to and dependent upon terrestrial soils.)
While I was busy playing with the internet, earth’s soil bacteria are running the planet’s biogeochemical cycles. These soil-dwelling microbes are quietly moving the Earth’s carbon, nitrogen, oxygen, sulfur (and other elements!) through the biosphere using a series of metabolic handoffs. The bacteria may just be trying to get some energy (we might say, “Eat!”) by moving a few electrons around. Collectively, these reactions produce the atmosphere we breathe, the greenhouse gases and feedbacks that drive our habitable global climate, and fix the soil nutrients required for plants to photosynthesize.
The Final Frontier
Not only do we rely on these soil microorganisms for the air we breathe and the food we eat, we don’t know very much about them. From the UN FAO Soil Portal: “Soil biology plays a vital role in determining many soil characteristics, yet, being a relatively new science, much remains unknown about soil biology and about how the nature of soil is affected.” We’re still learning how human activities affect soil microbes, often in unintended ways.