Phosphorus is one of those chemicals that people may have heard of, but few know much about.
We have known about phosphorus since 1669 when Henning Brandt of Hamburg discovered that it could be distilled from urine. By collecting the vapours from urine and condensing them in water, he created phosphorus. It may seem odd today, but many of the earliest discoveries were made by boiling urine or using it for various industrial purposes.
Brandt kept his discovery secret because he thought he had discovered the Philosopher’s Stone, a substance that would transmute base metals, such as lead, into gold. He was wrong. Phosphorus does not turn lead into gold. When he ran out of money, he sold his process to a man who exhibited it all around Europe. Soon after, phosphorus was discovered in bones, so the process of boiling urine was little used.
Phosphorus is an active chemical. It is never found in its elemental form because it will combine with many substances to form compounds. Most commonly, phosphorus is found in two forms: white phosphorus — a white, waxy and toxic chemical; and red phosphorus — a mostly inert compound that is relatively harmless. White phosphorus is commonly used in flares and other incendiary devices. Red phosphorus is commonly the reddish coating on a book of matches used to light safety matches. Phosphorus can be found in other forms, too.
Phosphorus is used to enhance some of the properties of steel during its production. Its use in detergents has been reduced greatly because phosphorus in wastewater can lead to algae blooms, which block the sun to the water depths and stops photosynthesis. This leads to the death of aquatic organisms and the depletion of oxygen in the water.
Yellow phosphorus was used to make matches and glowing watch faces in the 1800s. Female employees — it was usually girls who did this work — used small paint brushes to paint the dials. Unfortunately, to make the point of their brushes fine, they were taught to lick the brush. This resulted in a condition known as Phossy Jaw. It started with toothaches and swelling of the gums. Soon it spread to the jawbone and caused abscesses and tooth loss. Finally, the bone of the jaw would die, and the phosphorus poisoning would cause brain damage.
By far, the greatest use for phosphorus is in the manufacture of fertilizers. When you go to your garden centre to purchase something to help your flowers grow, you will see three numbers on the bag. The first is the nitrogen content, the second is the phosphorus content and the last is the amount of potash.
Phosphorus is an essential element for life. We each contain about 750 grams of it in our bodies and consume about one gram each day. It is a major constituent in the chemical adenosine triphosphate, vital to energy transfer in our cells and it also makes up the sugar-phosphate scaffold that makes up DNA and RNA in our cells.
Phosphorus is mined on industrial scales to produce fertilizers. Large quantities of the phosphorus-containing mineral apatite are mined each year with the top three producers being China, Mexico, and Morocco. Large reserves are held by China, Morocco and the United States.
Phosphorus and fertilizer, in general, are critical to feeding the world’s population of more than 7.5 billion people. Without fertilizer, millions who are living a hand-to-mouth existence now would starve and many more would be pushed to the brink of starvation. Fortunately, we still have plenty of phosphorus, however, it is estimated that peak phosphorus production will occur by 2050 or sooner. After that time, the production of phosphorus will gradually diminish, and we will have run out of a critical resource to produce food.
There are methods being developed to recycle phosphorus in the future. But, unless we take the time to develop them now, we could be in for some mighty lean times in the next few decades. Technology has allowed us to continue to grow populations, but even technology will be helpless in the face of critical shortages of elements like phosphorus. Let’s hope we learn soon.
Tim Philp has enjoyed science since he was old enough to read. Having worked in technical fields all his life, he shares his love of science with readers weekly. He can be reached by e-mail at: firstname.lastname@example.org or via snail mail c/o The Expositor.