By Kimbel Westerson
According to Jim Elser, the only reason to care about phosphorus is if you drink water and eat food.
Elser is a distinguished sustainability scientist at Arizona State University’s (ASU) Global Institute of Sustainability, and a Regents’ Professor of Ecology, Evolution and Environmental Sciences. He’s also the co-coordinator of ASU’s Sustainable Phosphorus Initiative and has studied phosphorus for more than 20 years. He is convinced that if we can find a way to recycle phosphorus, we can secure food supplies and ensure clean water for future generations.
Most of us recall phosphorus being one of the elements on the Periodic Table – number 15 to be exact – but beyond high school chemistry and the label on multivitamins, we don’t know much else about it. All living things require phosphorus to live. Our bodies use phosphorus to synthesize calcium for bones and teeth, change food into energy, produce hormones and more. Phosphorus is an important ingredient in nucleic acids and is in our DNA. We cannot survive without it.
Plants can’t survive without phosphorus either and it is a key ingredient in the synthetic fertilizers that make high agricultural yields possible… but there’s a finite supply. Phosphorus is derived from phosphate rock, and global deposits are dwindling. As supplies decrease, prices increase (from $100 per ton in 2000 to $850 per ton in 2008), and those who need the fertilizer—especially those in developing countries—can’t afford it. In order to feed the earth’s 7 billion people, the supply and affordability of phosphorus has to be protected, or the supply increased. Increased? Impossible, since the supply is finite. Conserved? Certainly. Recycled? Working on it.
AN INDISPENSABLE NUTRIENT
Elser is also a principal investigator and member of the steering committee of the Sustainable Phosphorus Initiative’s Research Coordination Network (RCN). The RCN is meant to bring experts in various disciplines into better communication with each other to integrate projects and focus on new analyses to answer questions about reducing phosphorus waste and recycling phosphorous.
Phosphorus is an indispensable nutrient for plants, but only one-third to one-half of it is used in the plants’ fertilizer. Some gets trapped in the soil, but much of it gets leached out or eroded off. When it infiltrates water supplies, a chain reaction starts: phosphorus causes algal blooms, bacteria consume the algae and suck up oxygen, and lack of oxygen suffocates aquatic life creating areas where plant and animal life is unsustainable. The most infamous of these areas is the 5,840-square-mile (about the size of Connecticut) “dead zone” in the Gulf of Mexico.
There are sources of phosphorus besides phosphate rock deposits. Every well-nourished human wastes phosphorus every day in their – well – waste. Wastewater treatment plants have been removing phosphorus from water for as long as 40 years because their phosphorus-rich water was another cause of algal blooms. Now, effluent treatment facilities have started to use a process that transforms sludge destined for a landfill into struvite, a pellet that can be used in fertilizer that’s commercially viable. Studies are underway about treating animal waste in the same way.
Another issue is food waste. Elser says about 50 percent of the global food supply “is lost before it even gets to the plate.” In developing countries, waste happens mostly between the farm and table as spoilage. Most of the discarded food ends up in landfills. “There’s a lot of energy in that food. There needs to be technology to extract that energy value and get that phosphorus back to a field where it belongs,” Elser says.
THE PHOSPHORUS FOOTPRINT
Being mindful of our carbon footprint is a familiar concept, but what about a phosphorus footprint? To conserve this precious supply, consider making some simple changes. Americans love lawns. According to information gathered by the U.S. National Aeronautics and Space Administration, grass grown for lawns could be considered America’s largest crop. There are about 31.6 million acres of turf – almost 50,000 square miles – in the United States. Consider the tons of fertilizer applied to green up those yards every year, and xeriscaping or using organic lawn care could be a good alternative.
Since meat production is an inefficient process for phosphorus, consider eliminating or decreasing meat in the diet. Those who aren’t ready to become strict vegetarians can consider becoming demitarians, people who have committed to decreasing their meat consumption for environmental and personal health. Some restaurants already offer demitarian choices, serving the same entrée with only half the meat. Other people choose to go organic. The U.S. Department of Agriculture’s National Organic Program prohibits the use of synthetic fertilizers on organic farms.
Some sources project phosphorus production peaking as soon as 2035. Yet as prices increase, users may get by with less, and suppliers will need to find or create new sources. But since there is literally no way to make phosphorus – no way to synthesize it in a lab – and no way to produce food without it, research on conservation and recycling is imperative. As Elser says, this may be “the biggest problem we’ve never heard of.”