Science of Biosolids Odors

I am a science nerd and always have been. Just this week I got real excited by ”Harvesting therapeutic proteins from animal slobber” in this week’s(2/22/2017) Chemical & Engineering News, just as I was about “Slow-release nitrogen fertilizer could increase crop yields: A new nanoparticle-based fertilizer…” in the same issue. I spend several hours a week updating my EndNote database, where I have cataloged over 3,000 science journal articles. I received my tee-shirt this week: March for Science – Earth Day 2017. I occasionally, for fun, visit the National Center for Emerging and Zoonotic Infectious Diseases (NCEZID) just to catch up. I jump at the chance to encourage people to listen to The Great Courses audio lecture series Earth's Changing Climate.

I take science seriously, which explains my annoyance at seeing the negative news clipping below and receiving word that David L Lewis is again pretending to be an honest whistleblower scientist fired by the US EPA over his opposition to Part 503 regulations.  Apparently a new documentary is in the works featuring Lewis as a hero: How EPA Faked the Entire Science of Sewage Sludge Safety: A Whistleblower’s Story.  It was just in January that I started out a newsletter noting that "David Lewis, long-retired from EPA but not from anti-biosolids activism, has posted to the United Sludge Free Alliance his 'recommendation for a new EPA Clean Soil Standard'.”   And this week I learned that Caroline Snyder has been stirring up folks in eastern Pennsylvania that there are no science articles showing biosolids is safe. THIS IS NOT TRUE!

Lewis’s argument of biosolids risk is absurd on its face. Virtually every state and federal regulatory system accommodates and supports biosolids recycling; that is hundreds of environmental regulators. Virtually every scientific article finds positive attributes of biosolids use in soils; I have 600 such references, authored by probably more than 1,500 scientists. The wastewater profession backs this practice; WEF counts itself having 33,000 members. For Dr. Lewis to be on the right side of this issue, these scientists, engineers, and regulators would need to be in some sort of mass conspiracy. How can rational media reporters be so blind to this absurdity?

The “fake news” story that is told around biosolids follows common themes of mythology. A number of years ago, Pulitzer Prize winning science writer Jon Franklin explored this theme in“Biosolids Hits the Fan” presentation to the opening general session the last time the national biosolids conference was held in the Seattle vicinity.

This argument has also been provided a veneer of respectability by several journal articles, now over a decade ago. Lewis made that case in Interactions of pathogens and irritant chemicals in land-applied sewage sludges (biosolids). He speculated that “an increased risk of infection may occur when allergic and non-allergic reactions to endotoxins and other chemical components irritate skin and mucus membranes and thereby compromise normal barriers to infection.”

Works by other familiar anti-biosolids activists have appeared in technical journals. Today’s most active activist, Carolyn Snyder, authored in 2005 for the International Journal of Environmental and Occupational Health the article The Dirty Work of Promoting “Recycling” of America's Sewage Sludge. Helane Shields authored in 2003 for an online publication, NEW SOLUTIONS: A Journal of Environmental and Occupational Health Policy, an ominously titled article Sludge Victims: Voices from the Field.  And in that same year and in the same publication, a more extensive treatment of the claims of biosolids-related illness was set forth by Cornell Waste Management Institute’s Ellen Z Harrison, Investigation of Alleged Health Incidents Associated with Land Application of Sewage Sludges: “Residents near land application sites report illness. Symptoms of more than 328 people involved in 39 incidents in 15 states are described.” A journal article with a theme linking biosolids use to environmental justice is Public Officials’ Perspectives on Tracking and Investigating Symptoms Reported Near Sewage Sludge Land Application Sites.  The authors of this paper observed: “Residents living close to treated farmland have reported becoming ill following land application of sludge. No systematic tracking or investigation of these reports or of land application practices that could affect off-site migration of chemical and biological constituents of the sludge has occurred, however.”

These “science” articles share the specific feature that neighbors to land application sites are self-reporting symptoms of ill health.  This is not medical science.  Medical science is founded on objective measurements and on plausible mechanisms linking pathogens or toxins to health effects. These standards of medical science are not met with self-reported illnesses.

Nevertheless, WERF (now WE&RF) actively responded to these wide-spread and persistent public concerns. It sponsored research leading to the 2005 report. Health Effects of Biosolids Odors: A Literature Review and Analysis.  This review was followed by WERF’s more proactive Epidemiologi Surveillance and Investigation of Illness Reported by Neighbors of Biosolids Land Application Sites, Phase 1, “a draft protocol designed to be used by local, state, and federal health and environmental officials,” and by Pilot Testing: Surveillance and Investigation of the Illness Reported by Neighbors of Biosolids Land Application and Other Soil Amendments, which tested the protocol.  This project had its bumps in the road, in part because the Phase 1 authors were in disagreement with the focus and findings as they were shaped by the project review team. One underlying issue is this: are people who believe they have been sickened by biosolids exposure in fact experiencing ill health?

I took a shot at the issue of whether, in the absence of pathogen and toxicant exposures, can biosolids make people sick? I had been put on to this topic by Dr. William Cain, the principal investigator of WERF”s first report on health effects, in a visit to his odor lab shortly after his WERF report was complete. He explained that the chemical sensing system, particularly the trigeminal nerves in the nose, could be triggered by biosolids odors and that odor triggers could cause physical reactions, even subconscious ones. After a long, circuitous path of journal reading, I set this argument down in 2007 in Biosolids Odorant Emissions as a Cause of Somatic Disease: What Ought to be Our Profession’s Response?  I convinced myself that we, as environmental professionals, ignore odor complaints at our peril. My basic argument is that we can reasonably predict that someone in a community affected by biosolids odors may become fearful and experience physical manifestations of panic arising from odors, not pathogens.

Over the past ten years, scientific tools for investigating pathogens and exposures are increasingly sensitive and affordable. Has science raised the level of concerns with biosolids-borne toxicants and pathogens? The short answer is no.

But we do now know a lot more about biosolids-borne microbes.  A series of reports were issued by Dr. Jordan Peccia’s lab at Yale University.  He and his grad students looked far beyond our traditional, regulation-inspired indicator organisms. In Toward a consensus view on the infectious risks associated with land application of sewage sludge he concluded “such analysis demonstrates that the tradition of monitoring pathogen quality by Salmonella spp. and enterovirus content underestimates the infectious risk to the public…”   In Source tracking aerosols released from land-applied class B biosolids during high-wind events, Peccia’s team concluded that “[T]he application of DNA-based source tracking to aerosol samples has confirmed that wind is a possible mechanism for the aerosolization and off-site transport of land-applied biosolids." Further, in Prevalence of Respiratory Adenovirus Species B and C in Sewage Sludge, the researchers asserted “[T]hese findings reinforce the necessity to consider aerosol exposure to sewage-derived pathogens."  But, in terms of actual risk, the evidence seemed to point to exposures not being of great health concern. In  Respiratory Toxicity and Inflammatory Response in Human Bronchial Epithelial Cells Exposed to Biosolids, Animal Manure, and Agricultural Soil Particulate Matter the article “…suggests that an inflammatory aerosol exposure in the TB region could only occur under worst case scenarios…,” which seems relatively benign.

The other major team looking at the microbial content of biosolids and its implication for worker and community health is at the University of Arizona, that of Drs. Ian Pepper and Chuck Gerba.  This team put out the report Pathogens and Indicators in United States Class B Biosolids: National and Historic Distributions, a “major study of the incidence of indicator organisms and pathogens found within Class B biosolids within 21 samplings from 18 wastewater treatment plants across the United States….illustrating that the Part 503 Rule has been effective in reducing public exposure to pathogens relative to 17 yr ago.”  As with the Yale work, this team’s graduate students studied Bioaerosol transport modeling and risk assessment in relation to biosolid placement, concluding that for nearby residents “little risk  of infection from aerosolized bacteria and at no risk from aerosolized viruses.” This works was also reported and confirmed in  Estimation of bioaerosol risk of infection to residents adjacent to a land applied biosolids site using an empirically derived transport model.  When the new assessment tool, QMRA, or quantitative microbial risk assessment, was applied to manures and biosolids, in Land Application of Manure and Class B Biosolids: An Occupational and Public Quantitative Microbial Risk Assessment, the researchers showed that “decreases in risk were typically over six orders of magnitude beyond 30 d. Nearly all risks were reduced to below 10−4 when using a 4-mo harvest delay for crop consumption.” These confirmed the effectiveness of Part 503 management regulations.

What can we say today with these new tools, new studies, new technologies, and new complaints? We still can confidently say that biosolids land application has not proved a significant source of pathogens that cause sickness in workers and communities. This is good, but not sufficient. Odors still provoke panic-related symptoms, so we need to continue our search for improved odor qualities. We should not be shy about offering to respond to claims of ill health effects of biosolids, because some of these reports arise from genuine fears. Class A pathogen treatment vastly reduces risks compared to Class B treatment, so our industry’s move to Class A is wise. Land management practices that prevent windblown dust, incidentally also reducing odorant releases, are always smart.

We know biosolids is safe, but our public does not. We need to go beyond our rational brain and toward our emotional nature, our heart, and follow our nose. Even the safest biosolids by any other name is Still Not a Rose.