Back Forty: How phosphorus helped create ‘a world out of balance’

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Workers clean algae on a beach in Qingdao, in China’s Shandong province. The algal phenomenon, an annual occurrence in Qingdao, is usually caused by an abundance of nutrients in the water, especially phosphorus. June 29, 2016. Photo by STR/AFP via Getty Images.

By Lela Nargi

Environmental journalist Dan Egan’s The Devil’s Element: Phosphorus and a World Out of Balance kicks off by describing how flaming nuggets of elemental phosphorus can incinerate human flesh, even after a few decades submerged in the ocean. With the danger of the periodic table’s 15th element thereby established, the book launches into a deep historical dive and a cautionary exploration of a substance that’s both critical to all life but also has the potential to eradicate it.

Phosphorus cycles endlessly through plants, animals, waste, rock and sediments, and humans have collected it from various sources for centuries. We’ve scraped bird guano off Pacific islands, mined ancient fossil beds, and more recently collected urine from university plumbing systems. In the pursuit of phosphorus, people have been exploited and entire ecosystems destroyed. Mining on the guano rich Pacific atoll of Banaba, part of Kiribati, stripped away 90 percent of the island’s surface. Chinese workers similarly mining Peruvian islands were exposed to toxic dust, beaten, and killed for trying to escape.

Early alchemists tried to make gold from the phosphorus in urine; during World War II, British military researchers included it in chemical weapons; and soap makers still use it to make detergent more effective.  But most of the world’s phosphorus has been used to restore productivity to crop fields and stave off famine in burgeoning populations. The element plays a key role in photosynthesis, and it helps boost crop yields, root growth, and fruit and seed development. The element is a good part of the reason, Egan writes, that “Earth’s food production has been able to double in the last half century.”

Globally, farmers apply around 25 million tons of phosphorus a year, but 14 million of those tons aren’t taken up by plants. Instead, rain and snowmelt wash phosphorus off fields and into waterways where — along with nitrogen from fertilizer — it spurs the growth of algae and other plants. The result is low-oxygen dead zones that harm aquatic life. Algal blooms can also produce toxins that contaminate drinking water and recreational water bodies.

In 2019, for example, unprecedented spring storms flushed fertilizer from farm fields in the Midwest into streams and rivers that flow to the Gulf of Mexico. This triggered a “first-of-its-kind” outbreak of a potent blue-green algae called Microcystis, “which ecologists thought could not survive long along open coastal saltwater,” Egan writes, and a massive die-off of marine life. The disaster was a sign that until “there are dramatic changes in the way agriculture is regulated, things are going to get worse.” Egan calls for reform of the Clean Water Act, which regulates the discharge of pollutants from pipes into rivers and streams but excludes runoff from farm fields, allowing the ag industry, says Egan, to “pollute with impunity.”

Much of The Devil’s Element is structured around a central irony that gives Egan’s arguments shape and purpose: phosphorus is plentiful but its supply is not infinite. The world’s largest reserves, which occur in the Western Sahara and are controlled by Morocco, are predicted to tap out at the end of this century, and yet we continue to squander this resource. One of Egan’s sources estimates that 80 percent of phosphorus intended for food production is lost — some of it during the mining process, but most of it from farm fields, including in regions that grow corn to make ethanol or to support the livestock sector.  

Rock isn’t the only source of phosphorus — animals produce it too. Egan argues that their manure, applied in proper amounts, could and should be a great source of fertilizer for farms, as it is in China and other Asian countries, and the book would benefit from more exploration of how other nations could overcome their disgust with this form of recycling. But regardless, in the U.S., due to a lack of affordable transportation between those with an abundance and those with need, manure doesn’t get where it could most be of use.

Instead, concentrated animal feeding operations (CAFOs) — which contain at least 700 cattle or 2,500 swine — spread their never-ending supply of shit across fields to fertilize grain crops and alleviate the abundance. But the land cannot absorb this volume of nutrients and again, Egan says, the majority washes away.

Egan, whose writing style is lively and engaging, doesn’t leave readers without some good news, although his final chapter, on solutions, is a bit thin. He describes efforts in the U.S. to collect and convert our own bodily wastes to use as fertilizer, and he applauds the states that ban phosphorus-based lawn fertilizers (currently 11 of them). Egan believes our mounting phosphorus problems are solvable if only we could muster the will. A “logical next step,” he argues, is for “Congress to revisit the agriculture exemption from the Clean Water Act” to hold large-scale farmers accountable.

Is legislation on the matter even possible? President Biden’s new Waters of the United States rule, which Congress recently rejected, left ag exemptions intact, which doesn’t bode well. But a public ever more exasperated by closed beaches and contaminated tap water just might — we can hope — force the issue.

But barring a sudden and massive shift in how we move goods, plants, animals, and ourselves around the planet, fungi are going to find their way everywhere. They are just too well adapted to the modern moment. “We haven’t simply opened Pandora’s box,” Monosson writes, “we have swung it around and shaken out the contents.” Still, we can each follow best practices. Don’t import exotic plants or animals. Learn to love those little red bananas. And occasionally, check yourself for new tendrils in strange places.