Research Updates by Sally Brown, University of Washington

Soil Health

Clearly, we have all been more than a little obsessed with our own health and well-being lately. The library this month is also about health and well-being, but with a focus on soils.   This is prompted by the Climate Action Reserve that is working on developing a protocol to give credit to people who help heal soils.  There is a good chance that organic amendments are high up there in the tool box for this.  When/if biosolids rate credits is a real question.  Let’s start with sick soils.  Who would have thought that soils get sick?  Soil degradation has a long history, as do the negative impacts on people who depend on soils.  For that I’d recommend you get a copy of Dirt: the Erosion of Civilizations by David Montgomery.  Speaking personally, I have had enough death and destruction for the time being, so I am not going to read that book by Montgomery.  We know how to fix soils, or at least we have a pretty good general idea.  Instead of focusing on destruction, let us focus on restoration. 

The first paper in the library, Soil health and sustainability: managing the biotic component of soil quality, is a very nice review of the whole concept of soil health and why it is important.  Over 40% of the world’s agricultural soils are hurting. This is from a combination of factors, including soil erosion, extensive cultivation, over-grazing, land clearing, salinization (too high in soluble salts) and desertification (turning soils into the Gobi desert equivalent).  impacts of poor soil health are also discussed, apart from not having enough to eat.  Excess nutrient runoff from soils and the creation of dead zones (areas of depleted oxygen) in fresh and salt waters are also a consequence of degraded soils.  The authors go over basic definitions of soil health; optimal functioning is the short answer.  They then spend a lot of time talking about the best ways to measure it.  We used to understand /study soils from three different perspectives.  We considered physical properties, biological properties and chemical properties.  The Soil Science Society of America even has three volumes on how you analyze each of these.  When you consider soils from a soil health perspective, it turns out that they are all related.  This makes the analysis extremely complicated. Simplified tools are critical, as not every person who works the soil is likely to install replicated field plots and have a large analysis budget with graduate students.  Ideally, indices are relatively simple and straightforward to measure.  They also reflect the interrelationship of the physical, biological and chemical.  That translates to low bulk density, good aggregation, and active soil food web and sufficient available nutrients.  The “take-home” quote here is: ‘Note that soil organic matter serves as a primary indicator of soil quality and health for both scientists and farmers’.  The table below shows a summary of the paper.

If you look at this summary, biosolids have the potential to fit in in several sections. We can be the medicine here.   In fact, two long-term biosolids sites are currently being monitored by the USDA as part of their soil health study.  One of those is Washington State University’s dryland wheat study, the other is in Colorado.  Many of the studies on land application of biosolids have focused on the safety, with a lens on the contaminant du jour.  Few studies consider the broader issue of biosolids and soil health without that requisite emphasis. 

The second paper in the library comes out of New Zealand: Composted biosolids enhance fertility of a sandy loam soil under dairy pasture  This is a relatively early paper (2004) and so there is a requisite discussion of metals, but the focus is primarily on benefits.  The authors applied composted biosolids to a pasture.  In addition to measures in the pasture, the authors also collected the soils and used them in pot trials.  They saw increased yield from the pot trials and improvements in soils from the field trials.  Higher carbon, nutrients, cation exchange capacity all increased.  From the microbial end, they also saw increased populations (a good thing), and those populations were carrying out their business (respiration and anaerobically mineralisable N).  This early paper used a range of indices and showed that adding biosolids compost to a field improved the health of the soil in that field. 

From there we go to a more recent study from England: Long-term effects of biosolids on soil quality and fertility. In this paper, the authors use the terms soil quality and fertility, but again are using a broad range of soil variables to evaluate the impact of biosolids on soil health.  This study has been in the library before but not with the lens of soil health.  Four sites received, biosolids applications over time at agronomic loading rates.  Measures included total and light organic matter, water holding infiltration and aggregate stability, available and total nutrients, and earthworm numbers.  In other words, physical, chemical and biological indicators were all included.  In all cases, the biosolids did the trick -- improvements were seen with response varying by soil type. 

The final paper of our series, giving evidence of the importance of biosolids on soil health, comes right from my state of Washington: Long-term crop and soil response to biosolids applications in dryland wheat.  The dryland wheat plots established by WSU in the 1990s, and now part of the USDA Soil Health study, were evaluated in this paper published in 2013.  The authors measured changes in yield, protein content of wheat, and soil carbon, nitrogen and phosphorus.  On the physical end of things, bulk density was measured.  Total microbial biomass and general types of bacteria and fungi were also measured.  Biosolids at the medium and high rates were the best: high yields, higher protein in the grain, lower bulk density, more carbon storage, higher nutrients and more critters.  The paper showed that the biosolids increased the ratio of bacteria to fungi in the soil.  This happened because of increases in the populations of aerobic, gram positive and negative and anaerobic bacteria increased.  Fungal populations stayed the same across all treatments.  Our knowledge of soil microbes isn’t sophisticated enough to really comment on this.  We can say that, in general, higher populations mean healthier as they reflect the fact that there is more to eat. 

So, three papers from three continents, all showing that biosolids improve soil health from the physical, chemical, and biological metrics used.  Will they count in the CAR protocol on soil enrichment? 

The last article in the library is the draft protocol: Soil Enrichment Protocol: Reducing emissions and enhancing soil carbon sequestration on agricultural lands.  If you want some dry reading, this fits the bill.  Developing a protocol to give carbon credits has to be a conservative exercise.  You are creating value out of too thick air, so to speak.  In my opinion, this first draft is over the top, despite that constraint.  I’ve submitted comments, including using newer values for default N₂O emissions (see February 2020 library) and using per ton amendment applied values for different amendments, again based on peer review research.  We will see what happens with this.  I know that the California Association of Sanitation Agencies has also submitted comments.   Strong research supports giving credits for organic amendment use to improve soil health.  It would be great if the CAR protocol recognizes this.  In the meantime, stay healthy.  Next month we go to contaminants. 

Managing Existential Risks of Our Biosolids Programs

“Existential Risk.” Just a few short weeks ago I had only a vague notion what that phrase might mean, and it was not the coronavirus pandemic alone that causes this phrase to be “front of mind.”  A lifetime ago, actually back on April 9, U.K. moral philosopher Toby Ord was interviewed for the Ezra Klein podcast (“Toby Ord on existential risk, Donald Trump, and thinking in probabilities”) discussing Ord’s exercise of framing the total scope of risks confronting the existence of humanity. No small questions on Dr. Ord’s mind. Spoiler alert, he opines that humanity’s existential risks, the ones that give us a combined chance of 1 in 6 of not reaching 2100, arise from “unaligned” artificial intelligence and from engineered pandemic viruses, not climate change and global habitat destruction, as I had expected. But he arrives at this conclusion from a rigorous, objective analysis of probabilities of risk. That approach had me download to my Kindle his book, The Precipice: Existential Risk and the Future of Humanity.  The book is half appendices; Ord gets deep in the weeds on his methods of comparing and overlaying risks. These methods are relevant to biosolids management.

I am wide open today to learning about risks. A colleague sent The New York Times opinion piece on risk, Embracing the Uncertainties, and this directed me to another article,  The Pandemic Isn’t a Black Swan but a Portent of a More Fragile Global System. “Black swan” is a concept of another “big thinker,” Nassim Nicholas Taleb, who co-authored a prescient article in January “Systemic Risk of Pandemic via Novel Pathogens—Coronavirus: A Note (1/26/2020).” Taleb is also author of the 2012 book Antifragile: Things That Gain from Disorder, which I also downloaded to my Kindle

The common thread of these two books is the argument that existential risks of global proportion require that humanity has governance systems able to quickly deploy rigorous science and compel global mutual action. Ord argues that the coronavirus may cause humanity to forge new global responses.  Taleb explains that “antifragility” is a concept where “errors create benefits… gene pools take advantage of shocks to enhance its fitness.” Today, humanity is fragile and is not set up for global response. Our national and local leaders focus on the front of a risk curve, rather than the far end of the curve.

Coronavirus may be the lever that causes humanity to develop effective responses beyond the pandemic to global climate change. Maybe not. The article, “After the Coronavirus, Two Sharply Divergent Paths on Climate,” presents both cases. The path toward climate action is not foreclosed, and that is my hopeful view, a view I learned in another podcast I share with Bill Gates.

Risks in the years ahead arising from fragility of our economy and environment are huge, even beyond the risks posed by the coronavirus. Our economic system is fragile: America’s (Still) Committing Economic Suicide: Why America is Facing Unprecedented Economic Disaster. Our food system is fragile: How resilient is the United States’ food system to pandemics? and Coronavirus Exposes Our Food System's Crisis, The coronavirus outbreak may be in part a result of environmental destruction (Coronavirus Pandemic Linked to Destruction of Wildlife and World's Ecosystems).  We have experienced the fragility of our health care delivery system, here in the U.S. and globally: The Curve Is Not Flat Enough.  And we see, too, the fragility of education and communication systems that have given short shrift to, and undermined the prestige of, science: Communicating uncertainty about facts, numbers and science. 

Our biosolids treatment and use programs are fragile. Ord’s The Precipice underscores the weakness of groupthink that hides risks and fragility from clear view and diverts our attention to risks that are not most important.  Our profession has a predictable perspective on risks that is revealed in the topics we cover in conferences, professional papers and research. Our attention has been commanded recently by PFAS and other persistent organic micropollutants: PFAS get the updates at the NEBRA PFAS webpage; and, pharmaceutical and personal care products, receives extensive review articles and cutting edge research.  Our attention is given to microbes and pathogens, with a search for new indicator organisms (including viruses) and for risks to workers and the public from potential exposures during land application.  Our attention is on technology solutions purported to lower risks, as with sustainable, low carbon footprint “Class A EQ products.”  We have given attention to odors as a health risk, showing that the risk is low, and we have learned that odor is a community nuisance issue, because our attention is grabbed by angry neighbors who are a risk to our programs. Our attention has been grabbed by naysayers who argue there is a risk from adverse effects of biosolids on soil quality, and we responded by having our national and international research organizations demonstrate biosolids pose low risks and offer significant benefits.

Our biosolids programs remain at risk, and we ought to figure out how to describe those risks. Toby Ord deploys a method of risk calculation that has a strong historical component. For example, he asks, over the 200,000 year of modern human species, has disease wiped out our species? No, in the worst known event, 30% of regional populations were lost to the plague in Europe in 1347, which, while horrible, does not rise to existential risk to humanity. He deploys scientific estimation. For example, even at “fat-tail” of risk projections, climate change raises sea level 250 feet and average global temperatures 14-degree F. At this fat-tail of climate change risks, human civilization will persist somewhere on Earth, though much further north. Existential risk to humanity is for keeps, and the ability of humanity to understand this risk and respond effectively is vital for humanity’s survival.

Have we as a professional practice missed opportunities to better understand risks in biosolids management?  First, following Toby Ord’s approach, we can ask the question, what kinds of risks have caused significant failures in biosolids programs over the past 50 years (using Earth Day as the starting point)? Second, we can ask the other question that Ord uses, and to which he ascribes significant risk, and that is what role may be played by “unknown risks?” As a thought experiment, Ord would have us ask experts in 1920 what are the greatest risks to humanity? They would have understandably answer that warring global powers and flu pandemic were top risks, and, also understandably, they would not point to nuclear weapons, climate change nor artificial intelligence. Third, we can ask Taleb’s question, are our systems designed to be unbreakable, which is good but not great, or are they designed to be adaptive and flexible, a better place to be, and thereby antifragile?

In our biosolids management systems, what might be the experience of historical risks, hidden risks, and fragility? I am now going to draw on my 30 years of biosolids experience at Philadelphia Water Department, rather than on an objective consensus of science and colleagues, which is really what we should one day seek. Here it goes. For microconstituents, I have lived through pesticides, PCBs, flame retardants, dioxin, radioactivity and triclosan; no one compound has caused the industry to stop in its tracks, or be seriously slowed, except in specific cases (see below). I have managed biosolids that has, on occasion, resulted in extraordinary plumes of odorous air, seriously upsetting neighbors and regulators alike, but we “managed” the nuisance, and “met our targets.” Our workers were afraid of bacteria and endotoxins, and had high hopes for “hazard pay,” but 20 years of medical monitoring of over 100 operators and annual industrial toxicology review of their records showed no ill-health among these “highly exposed individuals.” We took a deep breath, and sponsored soil health research by a skeptic at  Penn State, and the findings were mostly benign (On‐Farm Assessment of Biosolids Effects on Soil and Crop Tissue Quality). I had my challenges working down the seemingly never-ending list of risks, ones that are commonly cited as risks in our biosolids planning studies, but none of these categories rose to a level of existential risk for my biosolids program.

Philadelphia’s real risks were not the common ones, but rather in the “fat-tail” of probabilities. The “game-changing” events that seriously impacted its biosolids program are worth taking a quick look at. The first event was the risk of technology failure. Philadelphia participated in a federal grant for innovative technology that had the city build the largest static-pile, negative aeration, open-air biosolids composting facility, the first full-scale facility of its kind along a principal transportation corridor. Intractable odors caused it to close suspend operations after 18 years of struggle. The second event was sudden releases of toxic contamination. On two occasions, point source discharges of gigantic quantities of contaminants occurred, first DDT compounds and second PCBs, creating a nightmare of testing, tracking and quarantining that makes the nightmare of coronavirus feel familiar, with years of game-changing consequences. The third event was a fire caused by employee negligence. The fire caused by careless welding resulted in a total loss of the city’s compost mixing building due to fire. Technology failure, toxic releases, and worker negligence -- these categories do not typically show up in biosolids master planning, triple bottom line evaluations, life cycle assessment or the other tools for developing biosolids programs.

This brings us to the “unforesee-ability” of the pandemic. MABA surveyed its membership in early April on risks to biosolids programs posed by coronavirus. The highest reported risk is one that is, yes, novel. Solid waste shipments to landfills have dropped significantly, a result of a sharply reduced economy, and thus solid waste deliveries are insufficient for adequate commingling with biosolids, thereby causing shutdown of biosolids deliveries. This is a risk factor unforeseen and unforeseeable in biosolids management plans.

Ord and Taleb both point to an approach for unforeseeable, novel risks. They say we need governance systems that are fact-based, vigilant, responsive, flexible, and, importantly, collaborative across societies, or, in our case, across the entire biosolids profession. In reading this recommendation, I recall the example of the Center for Army Lessons Learned, and see it as an “antifragile”  system for responding to unforeseeable risks, This Center is committed to “forward thinking, aligning resources..., fostering readiness... and informing the future,” building “antifragility” into a system otherwise prone to being a top-down, hardened infrastructure environment, which characterizes not only the U.S. Army, but also many biosolids programs.