Phosphorus is a lynchpin of our food system states ScienMag, the reason why is that plants cannot grow without it and [it] has no substitute. Phosphorus is also a component of nucleic acids (DNA and RNA), essential for cell membranes, for energy transactions in all living cells, and critical for teeth and bones*. We need to better manage phosphorus, both as a vital element essential for food production and life, but also an element behind environmental pollution that results in damage to aquatic biodiversity and habitat. Join me in exploration of this element.
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What is Phosphorus
Phosphorus is 7th most common element on earth and is found in rocks, soils, plants, and animals, including us. It is a necessary component to all life, but is also a commodity processed and sold on the global market.
It was first made by Hennig Brandt (Hamburg, Germany) in 1669 when he evaporated urine, heated the residue to red-hot, and using water, captured the distilled phosphorus vapor (1). It has come up again as an issue due to Putin’s ongoing war in Ukraine and the disruption that is causing in the delivery of fertilizer; it is highlighting global food security risks associated with reliance on critical imports like phosphorus.
- Ironically, during WWII the Allies used phosphorus incendiary bombs to destroy Hamburg, the place where phosphorus was first discovered.
The thing about phosphorus is that it has those two sides: as a deadly explosive with fire capacity, and as a farming and life necessity. This is thus a compound that is highly regulated in the USA.
Geology
The two main forms of phosphorus are white phosphorus and red phosphorus. In nature these two forms are combined, and are some of the compounds found in minerals. Rocks with apatite minerals are what white and red phosphorus is made from. As a finite resource, there are concerns that after 2050, given current use, the rock sources will dwindle; and as with oil reserves, geopolitics come becomes part of the discussion.
- White phosphorus is a poisonous waxy solid and contact with skin can cause severe burns. It glows in the dark and is spontaneously flammable when exposed to air. So no surprise, it is used in flares and incendiary devices, but also flame retardands, pesticides, nerve agents and water treatment.
- Red phosphorus is an amorphous non-toxic solid, and is part of the material on the side of matchboxes, that matches striked to light.
Columbia (2013) wrote, phosphorus cannot be manufactured or destroyed, and there is no substitute or synthetic version of it available.
Phosphorus Uses
Phosphorus is important in the creation of steel, some detergents (which is not a good thing, and should be phased out), special glasses, fine chinaware, various brands of fertilizer, and food additives.
- It is also used in food, like Soda for example. We already know that soda and sugary beverages are a risk factor for diabetes, heart disease, obesity, and tooth decay. But did you know that most sodas contain, either or both, phosphoric acid and citric acid? That is what is behind the wear of enamel, sensitive teeth, and vulnerabilities.
But for my post, I am concerned with ammonium phosphate, or fertilizer. The process to make this, is to take the ore, convert it into phosphoric acids, and then convert that into ammonium phosphate. This fertilizer is vital for food production, and is one of three nutrients (nitrogen, potassium and phosphorus) used in all commercial fertilizers.
- Interestingly, Australian and American Indigenous People were managing phosphorus without even knowing the chemical details of what they were doing. To manage their hunting and foraging grounds, they used fire, which effectively fertilized the landscape with biologically available ash-based phosphorus (2).
- Historically, in agrarian societies, farmers learned to use compost and manure to maintain field fertility.
- The sewage of the Aztec empire fed its famous floating gardens (3), in China this was known as “the business of the golden juice.”
- Even not that long ago, “night soil” was collected from humans for fertilizer.
But this all seemed to stop with the Sanitation Revolution (4, 5), that followed closely on the heels of the Industrial Revolution, and brought with it the yuckiness of waste.
Biology
Royal Society of Chemistry writes that phosphorus is essential to all living things. It forms the sugar-phosphate backbone of DNA and RNA. It is important for energy transfer in cells as part of ATP (adenosine triphosphate), and is found in many other biologically important molecules. We take in about 1 gram of phosphate a day, and store about 750 grams in our bodies, since our bones and teeth are mainly calcium phosphate.
- Calcium is the most abundant mineral in the body, second is phosphorus
- ~85% of our body’s phosphorus is stored in bones and teeth.
There are sources of phosphorus, outside of the rocks, and that is when we consider that animals and humans excrete almost 100% of the phosphorus consumed as food; if only we accessed it as part of processing waste. For farmers, this means putting the plant and farm animal waste back into the ground rather than buying fertilizers. It also means we ought to consider our waste not only processed back into usable water, and also collect the chemicals, such as phosphorus, to reuse.
It also means going back in history to look at food plants that may have once had the ability to utilize phosphorus or locate it better than current plants. For example, in 2012, scientists identified a gene in an ancient variety of Japanese rice that enhanced the plant-roots ability to find phosphorus.
Not only selective plant breeding, but using no-till farming, terracing, contour tilling, and windbreaks could help as well. These farming techniques would reduce soil compaction, soil disbursement, and encourage good root development, all of which would help plants access more of the legacy phosphorus. Also, adding symbiotic fungi and companion crops could help extend a plant’s roots, and some plants secrete phosphorus-releasing compounds to free up phosphorus that may be locked in the soil (6).
Environment
Ninety percent of the global phosphate rock reserves are located in just five countries: Morocco, China, South Africa, Jordan and the United States (7). But reportedly, only 20% of the phosphorus in rock form reaches the global food supply chain. Nearly 30-40% is lost during mining and processing, 50% is wasted in the food chain before getting the food to us, and globally, only half of all farm manure is recycled back into the soil.
Most of the wasted phosphorus enters our waterways from agricultural (manure) runoff. Along with phosphates from detergents dumped into drains. The result is eutrophication, a form of water pollution leading to algae blooms and consumption of oxygen, thereby creating “dead zones” in lakes and oceans where nothing can live. In 2013 it was estimated that 400 coastal dead zones existed at the mouths of rivers, and were expanding 10% percent per decade.
One way to help, is to first use up all the over-fertilization farmers have done for decades, which is called “legacy phosphorus.” Using up what is currently just sitting in the soil would reduce immediate costs from not importing fertilizers, and would reduce runoff as the fertilizer compounds in the soil start to get used up (8); and this is needed as, according to one study, phosphorus pollution affects ~40% of Earth’s land areas.
Phosphorus and Food
Crop and livestock production in the UK is almost entirely dependent on imported phosphorus in animal feeds and fertilizers. They import ~174k tons of phosphorus annually. Much of these imports come from countries including Russia, Morocco and China. But in the news recently, is the impact of Putin’s War on the global supply chain. This has caused both reduction in available material, and a quadrupled fertilizer price between 2020 and 2022. Additionally, it is causing people to rethink the entire global use of phosphorus, and to consider ways to replace the one-way supply chain, with closed cycles (9).
Industrial Agriculture
The recycle of manure is hard to do in our Industrial Agriculture system. The Factory raising of thousands upon thousands of farm animals is often geographically distant from crop growing. Which results in logistical problems of getting the manure from the factory to the crop fields. (Small to medium sized family farms do not have this problem.)
Additionally, the USA population has a lower tolerance for the yuck factor, we do not eat all of the meat we butcher due to yuck (eating chicken feet, beef tongue, turkey necks, etc), or the ideas of using processed human waste on our food fields, or of reusing water from our waste are all yucky. However, in the UK, and many other places are now adapting technology to provide efficient removal of both nitrogen and phosphorus from the water it treats (10).
Our Phosphorus Body
Our richest food sources for efficiently absorbed organic phosphorus are: dairy, legumes, nuts, poultry, red meat, and seafood. Whereas, plant foods like seeds, legumes, and whole grains contain a storage form of phosphorus called phytates or phytic acid that can reduce phosphorus absorption. It turns out that our bodies lack an enzyme needed to break down phytic acid, so it just passes through our digestive tract. But we can use cooking techniques to help break down the phytic acid and help absorb phosphorus more easily; that includes sprouting and soaking.
- A deficient level of phosphorus in our bodies is called hypophosphatemia, and toxicity from phosphorus is called hyperphosphatemia (11).
- Did you know that the overuse of aluminum-containing antacids, can bind to phosphorus and increase the risk of a deficiency?
Inorganic phosphorus is a processed form that is found in processed food. It is used to preserve color, moisture, and texture; and it is those additivies and preservatives that are a significant source of the phosphorus we consume, nearly 30% in the USA diet (12). Inorganic phosphorus is very easily absorbed in the gut, according to HSPS Harvard, ~90%, compared to ~40-60% from natural animal and plant foods (13).
Nutrition Labels
When looking at nutritional lables, phosphorus is often listed as: phosphoric acid, dicalcium phosphate, sodium phosphate, and trisodium phosphate.
What needs to happen
Not sure there is much we individually can do (bolded below), but we as a social community can do a lot.
- Make sure globally that detergents do not contain phosphorus.
- Improve the efficiency of existing mining, and its supply chain to improve efficiency.
- Cultivate food plants that have been selected for strong phosphorus-harvesting traits.
- Recycle human and farm animal waste to use manure as fertilizer.
- Start home composting from your food waste to assure phosphorus recycling in your own yard.
- Go back to harvesting bat guano for fertilizer, rather than synthetic made fertilizer.
- Make the application of fertilizer targeted, limited to what and where it is needed.
- Prevent soil erosion and agricultural runoff by promoting no-till farming, terracing, contour tilling and the use of windbreaks.
- Use technology to recycle water, nitrogen and phosphorus from waste systems.
Concerns
My spouse brought up that although talking about our waste is “yucky”, there are concerns about what we carry within us that might come out. For instance, if we already consume micro-plastics, and now have PFAS chemicals and medications in our body, and other things, what else besides phosphorus would we be putting into soil and thus our foods? Could our waste be toxic and ruin our food? A very good set of questions and I do not have all the answers. But we need not dump our waste directly in fields like we can organic manure, our waste can be filtered and processed.
But I can say movement is being made. For instance, TheAtlantic reports a Canadian company called Ostara has installed systems to extract phosphorus from wastewater at municipal treatment plants in more than 20 cities around the world, including Chicago and Atlanta. Switzerland and Germany have even passed laws mandating the recovery of phosphorus from sewage that will take effect over the next decade. And the Guardian, reports that in 2022 ~15% of the phosphorus in sewage is currently recovered around the world.
—Patty
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