Biosolids hit the fan

By Joel Preston Smith

This article was originally published in March 2012


PCC advocates buying organic and not just because of pesticides, antibiotics and hormones. Unlike conventional farmers, organic farmers can’t use sewage sludge as fertilizer.

It was one of the most hotly contested battles in developing national organic standards. Here’s why.

When Alice Cho Snyder and her husband Mark bought a 13-acre farm near Everett, Wash., last July, they thought they were going to be organic farmers, not the epicenter of a biosolids storm. Shortly after the Snyders closed on the property, Snohomish County officials notified the couple that biosolids were slated to be applied on 250 acres of land bordering their property.

“Biosolids” is a recycling industry term for sewage sludge that has been treated to remove most (or in some cases, nearly all) pathogens. After being somewhat defanged, biosolids are used as fertilizer or soil amendments.

The trigger words here — for the Snyders and for nearly anyone concerned with health and the environment — are “sewage” and “most” pathogens. Anytime a public agency or any other entity proposes spreading human waste, bacteria, viruses and other toxic contaminants over the landscape, regardless of the purpose, eyebrows are going to go up.

For the Snyders and those who don’t know much about sludge or how it’s applied to land, biosolids sound new, threatening and complicated. “We all want to support locally produced food,” says Alice, “but not if grown in sludge.”

Using sewage for fertilizer might sound threatening, at face value, but it’s hardly a new practice. About 7 million tons of dry sewage waste (most of it originating at watertreatment plants) is applied to land in the United States each year, according to the U.S. Environmental Protection Agency (EPA).

About 58,000 dry tons of biosolids were applied to agricultural lands in Washington in 2010, says Daniel Thompson, state biosolids regulator for the Washington State Department of Ecology.

Despite the inglorious name, sewage sludge isn’t just pumped directly onto land. The vast majority of biosolids fit EPA’s “Class B” category, meaning it has been treated to remove at least 95 percent of the pathogens in the original slurry (sewage isn’t just human waste; also it’s often composed of industrial effluent and/or storm water).

EPA sets limits on the presence of eight heavy metals (arsenic and mercury have the most stringent requirements). Few U.S. treatment plants are equipped to produce the more costly “Class A” biosolids — wastes in which pathogens have been reduced to a point “below detectable levels.” (Tacoma does.)

The obvious question is whether killing or removing 95 percent of the pathogens in a given volume of sludge is enough. Is it enough that in a given volume of sewage, only 5 percent of the E. coli, Salmonella, Shigella, Cryptosporidium, Giardia, Norwalk viruses (and potentially others) remain?

For more than three decades, EPA has offered a resounding yes. The agency has promoted biosolids as “safe and beneficial” at least since 1981, after first developing risk guidelines in 1979. The current EPA regulations (called the 503 Rule) for what the agency calls “sewage sludge” and “biosolids” came into effect in 1993.

Are biosolids safe?

David L. Lewis, Ph.D., a research microbiologist for EPA for 32 years, contends the agency based its 1993 regulations on “faked data” in an effort to “cover up adverse health effects from heavy metals and other hazardous
materials contained in the waste.”

Lewis, now senior science adviser for the National Whistleblower Center in Washington, D.C., says biosolids are “a serious threat to public health and the environment.” Lewis says he was fired in 2003 after authoring a series of articles in “Nature,” “Environmental Health Perspectives” and other publications that criticized EPA’s science policies and practices, and the agency’s management (and promotion) of biosolids in particular.

“Biosolids are one of the most regulated soil amendments out there,” argues Sally Brown, Ph.D., a research associate professor at the University of Washington in Seattle. “I use biosolids to grow my own vegetables. They’re a wonderful asset.”

Brown, who specializes in the ecology of soils and serves on the board of directors of the U.S. Composting Council, adds, “There’s nothing to be afraid of.”

Brown notes that biosolids have been used to reclaim soil health on several EPA Superfund sites, including the infamous Bunker Hill mining complex in Idaho, where mining operations begun in 1917 left 1.3 million cubic yards of tailings contaminated with lead, zinc and industrial wastes in the watershed of the south fork of the Coeur d’Alene River. The mine closed in 1981 and eventually became the locus of EPA’s largest Superfund settlement — $1.7 billion to date.

“Eventually we will run out of resources and disposal space, so we must redefine our definition of what is disposable …”
— Washington State department on ecology’s statement about one rationale behind using biosolids as fertilizer

And so it goes. There seem to be few agricultural practices as contentious and fraught with counterclaims as whether biosolids are a public health threat.

Farmers such as Alice Cho Snyder say, “The more we find out, the more we are convinced that this is a critical public health issue that needs to be addressed openly.”

Alice says she’s worried that if her neighbor’s application to use biosolids is approved by Snohomish County land-use officials, bacteria and toxins will wash over her property when the area floods, which she says it has — twice in the last five years.

A pathological legacy

The safety of biosolids has been addressed openly, but not conclusively. One question readers might ask is whether the agencies or entities that promote biosolids as safe are themselves competent to know (or say) what safe is (or means).

In 2002 EPA’s own Inspector General determined that the agency “does not have an effective program for ensuring land compliance” of biosolids, and thus “cannot assure the public that current land application practices are protective of human health and the environment.” The report also criticized EPA for conducting “virtually no inspections of land application sites.”

The Inspector General also castigated EPA for not collecting data on accumulated pollutants at biosolids application sites despite the fact that federal law requires the agency to collect such data. EPA also failed to monitor whether producers or appliers actually adhered to federal regulations. The Inspector General concluded that EPA’s failure to commit resources to the biosolids program constituted an “almost complete absence of a federal presence,” adding that the agency’s conduct “may result in increased risks to the environment.”

That was 10 years ago, which leads to the inevitable question: has EPA intensified its oversight of biosolids? When the Inspector General leveled these charges, EPA had 18 fulltime employees assigned to sewage sludge.

Current oversight

This past December, I requested current staffing data from the agency. Enesta Jones, a public affairs specialist for the agency, responded that “finding a precise figure was going to be hard …” The agency has yet to report so much as a single full-time employee currently working on biosolids.

These criticisms hardly inspire confidence in EPA as a biosolids regulator. But even the regulations themselves are suspect, according to Lewis and others. In February 2008, federal judge Anthony Alamo concluded the data used (in part) to develop EPA’s biosolids guidelines were “unreliable, incomplete and in some cases, fudged …”

Alamo’s condemnation of the science behind EPA’s regulations was issued during an Augusta, Ga., lawsuit. Several farmers alleged that biosolids shipped from a nearby wastewater plant had contaminated their jointly owned farm, killing several hundred cattle and forcing closure of the farm. Andy McElmurray and other farmers ultimately settled out of U.S. District Court for $1.3 million after arguing that high levels of chromium and molybdenum in biosolids were responsible for the cattle deaths, and for the loss of their livelihood.

No human deaths have been linked conclusively to biosolids (although one death has been alleged — that of Shayne Conner in 1995 in Greenland, N.H.). EPA’s regulations do make an attempt to minimize human contact with biosolids, by regulating how much time has to pass before crops in contact with biosolids can be consumed. The time lag is meant to allow a natural dieoff of whatever pathogens remain in Class B biosolids. The regulations, however, don’t set limits on any manufactured organic compounds in biosolids.

The research

In 2008 scientists from the U.S. Geological Survey and Colorado State University found that earthworms in soil plots amended with biosolids had bioaccumulated multiple human-manufactured compounds, including: disinfectants, anti-foaming agents and flame retardants, antibiotics, synthetic fragrances, detergents and pesticides, as well as other chemicals “reflecting a wide range of physicochemical properties” (Environmental Science & Technology, Feb. 20, 2008). Some of the same compounds were found in earthworms living in soils treated with animal manure.

In 2006 scientists from Eastern Washington University and the U.S. Geological Survey’s National Water Quality Laboratory found a total of 87 different human-manufactured compounds in biosolids originating from wastewater treatment plants in seven U.S. states. The researchers described biosolids as a “potentially ubiquitous nonpoint source” of “contaminants” in the environment (Environmental Science and Technology, Sept. 13, 2006).

“A minimum of 30 and a maximum of 45 [wastewater contaminants] were detected in any one biosolid,” the scientists noted.

EPA’s 2009 Targeted National Sewage Sludge Survey Report found 28 metals in every biosolids sample from 74 randomly selected water treatment plants in 35 states. The samples, collected in 2006 and 2007, also contained 72 pharmaceuticals, 25 steroids and hormones, flame retardants, and a variety of “semi-volatile organics and polycyclic aromatic hydrocarbons.”

Again, this is not comforting to the Snyders or other organic farmers. They’d like to know that when EPA says, “It’s safe,” it means safe. In the meantime, the Snyders are waiting for a hearing with Snohomish County officials. The state Department of Ecology approved an application to spread biosolids on the neighboring property, but county officials have argued that the state cannot preempt local land-use regulations.

Tom Rowe, permitting manager for Snohomish County, says the county is planning a hydrology survey of the area to determine what impact flooding (among other issues) might have on public health if biosolids are allowed. Rowe says the county plans to hold a public hearing on the issue.

Joel Preston Smith is a writer and photographer living in Portland.

Author’s notes

  1. Readers might wonder why biosolids are produced at all. The Clean Water Act of 1972 outlawed what was then a largely unregulated practice in the United States — dumping raw sewage or minimally treated human and industrial wastes into streams, rivers, lakes and other open bodies of water.

    EPA estimates the average family in the United States uses about 400 gallons of water a day, which doesn’t include industrial use. The portion that is wastewater can’t be dumped untreated, per the 1972 law. It has to go somewhere, thus the production of biosolids. It’s more costly, most treatment plants have found, to put it in landfills than to pay (in many cases) contractors to haul it away for use as fertilizer.

  2. In addition to removing 95 percent of the pathogens present in a given volume of sewage, the manufacturer and the entity applying biosolids to land are required to take steps to reduce the “attractiveness” of sewage sludge to pests such as mosquitoes, flies and other disease vectors.

    There are also EPA requirements for monitoring and reporting land application of biosolids. Note that EPA’s Inspector General has stated, however, that EPA is not monitoring whether the regulations are being followed. It should also be noted that EPA’s 503 Rule does not require that 95 percent of all pathogens be removed in order to merit a Class B designation for biosolids. The rule governs specific indicator pathogens, such as E. coli and Salmonella.

    One potential problem in relying only on indicator pathogens is the assumption that all pathogens in a given sample will respond to chemical or environmental purification procedures in basically the same way. Researchers have stated that about one entirely new pathogen is found in wastewater each year whose virulence as a disease vector in biosolids — due to the fact that the pathogen is new — isn’t known; without knowing what is in biosolids, it isn’t really possible to know that what is there is responding to purification treatments.

    The rationale for limiting the list to a series of “indicator” organisms lies in a desire for cost effectiveness for the producers of biosolids, which, for the most part, are municipal water-treatment facilities. It’s costly to test for pathogens; EPA has, in essence, determined that a given volume of sludge is unlikely to harbor enough pathogens (lying outside the list of “indicator” pathogens) to constitute a significant risk to the public.

  3. Regarding the tonnage of biosolids applied in Washington state annually: Marietta Sharp, a soil scientist for the Washington State Department of Ecology, points out that less than one-tenth of one percent of all agricultural lands in the state were amended with biosolids last year. “Most people [who’ve heard about the practice of using biosolids for fertilizer] think it’s a foot thick,” she notes. “It’s not.”

    Daniel Thompson observes that about 80 percent of biosolids produced in Washington are applied to land; the remaining 20 percent is burned in one of the state’s five incinerators. What isn’t clear is whether the state has included in those figures timberland, tree farms and other lands that do not produce crops for food consumption. If the State Department of Ecology includes those lands, that would tend to skew the figure toward the appearance of lower amounts of biosolids being applied overall. The department has not responded to questions regarding whether timberlands or tree farms were used in the calculation.

  4. Regarding the cost-effectiveness of producing biosolids: Sally Brown notes that “retrofitting [a Class B biosolids treatment plant to bring it up to Class A capability] can cost millions and millions of dollars, and they’re lucky right now if they can make payroll.”

    King County, she adds, recently found it would cost $27 million per treatment plant to bring its facilities up to Class A standards. Class A biosolids can be sold for home-garden composting, but Class B products cannot. It’s usually more cost effective to treat sewage only to meet the Class B standard.

    Daniel Thompson notes that about 12 percent of biosolids produced in Washington state meet the Class A standard.

  5. Readers may come to the conclusion that EPA’s management of biosolids is fraught with incompetence and/or negligence, that the agency has been influenced by political and economic concerns to the detriment of public safety, and has failed to rectify (or even address) problems identified by its Inspector General and the U.S. Government Accounting Office and others. This author believes such a conclusion is reasonably well-supported by a thorough survey of the allegations against EPA (the most troubling have been leveled by federal agencies) and the supporting evidence.

    The author also believes, however, that applying the same judgment to the Washington State Department of Ecology (DOE) isn’t merited. The DOE appears to have more staff developing biosolids policies, as well as regulating and monitoring the production of biosolids and the land applications themselves, than EPA has as a whole for the nation. If EPA ever does discover that it has tasked someone with managing biosolids, chances are the agency is doing far less to monitor sewage sludge than the DOE is. Daniel Thompson observes that Washington state inspects land application sites and “has a comprehensive regulatory program in place.” He adds that “most other states have their own biosolids programs as well.”

  6. Regarding the presence of personal-care products in biosolids: the researchers defined personal-care products as “fragrances, skin care and hair care products, insect repellents, cleaning products and flame retardants.” The American Society of Microbiologists has pointed out that the risks associated with toxins in personal-care products are higher in dwellings (where the products are being used to a greater extent than they are in the “landscape at large” and accumulate in dust) than they are in biosolids.

    A valid argument could be made that if the public was truly concerned about these compounds, it might be campaigning for their removal from personal-care products, rather than just worrying over whether the toxins are going to be found later in biosolids after passing through the human digestive tract.

  7. Untreated manures can harbor as many as 150 different types of enteric (occurring in the gastrointestinal tract of humans and other animals) pathogens, according to Charles P. Gerba, a faculty member with the Department of Soil, Water and Environmental Science at the University of Arizona, Tucson, Ariz. See “Sources of pathogenic microorganisms and their fate during land application of wastes,” Journal of Environmental Quality: 34:42–48 (2005). In asking whether biosolids are safe, it would be wise to consider their impact on public health compared with using untreated animal wastes, petroleum-based fertilizers, and other soil amendments that might present greater threats to the environment than do biosolids.
  8. One of EPA’s most troubling disappearing acts has been the removal of molybdenum from the watch list for heavy metals. EPA set a tolerance level of 75 mg/kilogram for Mo in 1993 but has since withdrawn the standard — not because Mo suddenly has been shown to be beneficial to humans, but because of a lawsuit against the standard.

    So, again, are biosolids safe? What concentration of Mo is acceptable in soil? EPA, in removing all restrictions on Mo, has said in essence said that what’s safe for you is whatever limit keeps EPA out of court. That essentially means no limits on Mo whatsoever. EPA, on the other hand, says, “Repeated exposure to molybdenum can cause increased uric acid accompanied by gout-like symptoms. In cud-chewing animals eating feed low in copper, molybdenum poisoning can be severe.”

    The Centers for Disease Control and Prevention, based in Atlanta, says, “Molybdenum is generally considered to be of low human toxicity, and clinical or epidemiologic evidence of adverse effects is limited.”

    EPA notes that it is planning to “reevaluate” Mo and the pollutants it discovered nine years ago in a 2003 biosolids survey. USDA states, “Following legal challenge, most Mo numerical standards were withdrawn, pending additional field-generated data using modern biosolids and pathway reassessment.”

  9. Regarding what “safe” means: It does not necessarily mean no one will be harmed. It involves probabilities and calculations, such as, at what level of occurrence of disease are the infected parties likely to seek medical attention, be diagnosed with a condition that can be linked with a reasonable degree of certainty with a specific cause, and so on.

    As for what is considered an “acceptable level of risk,” that involves a measure of probability that the alleged victim will enjoin the alleged source of the harmful agent (say a water-treatment plant) in a lawsuit, and win such a suit, with what damages awarded. “Safe” doesn’t mean you’re invincible. It just means the odds are in your favor. It’s an algorithm — a calculation of how likely you would seek a remedy if you’re harmed.

    The biosolids industry pointedly quotes a National Research Council (NRC) report, “Biosolids applied to land: advancing standards and practices,” July 2002: “There is no documented scientific evidence that the Part 503 rule has failed to protect public health.” It’s an old citation used by the Northeast Biosolids and Residuals Association and other biosolids promoters, and this author believes it is strictly true, to date. Strictly is the key word.

    The studies referred to in the NRC report have failed to demonstrate, under the rigors of the scientific method, human harm from biosolids. This does not mean there has not been or will not be harm. It means in some cases the methodology of the studies prevented researchers from reaching a scientifically valid conclusion demonstrating a relationship between harm and the presence (ingestion, inhalation, etc.) of pathogens or other harmful agents in biosolids.

    For example, scientists employed by the state of Virginia surveyed 23 scientific studies concerning the relationship between biosolids and human health and reported, “The observed health outcomes … included toxic exposures, viral, bacterial and protozoan infections, and irritation and allergic reactions.”

    Sally Brown notes the 2008 ruling in the McElmurray lawsuit (where McElmurray and others were awarded $1.3 million against a biosolids producer) was overturned. However, a reversal does not necessarily mean all evidence and arguments regarding EPA’s conduct automatically are negated (for example, whether the data the 503 Rule was based were “fudged” or not). See

    A reader might wonder, how can the industry claim there are no documented negative health effects if the studies, in fact, are reporting illnesses? The reason is that in many of the studies, the crucial step was not taken that might have demonstrated a linkage between biosolids and a given reported illness.

    The Virginia researchers note that in three studies that “documented complaints of gastrointestinal illness related to sewage sludge,” the authors of the study did not obtain “serological evidence.” In other words, people became sick; they had reported exposure to biosolids but the researchers did not follow up with lab tests that would have confirmed (or negated) the presence of pathogens. Researchers did not test the biosolids in question for pathogens.

    An examination of the studies shows a pattern where researchers note anecdotal linkage between illnesses and biosolids. Sick people. Biosolids. Not enough data. The conclusion? Biosolids are safe.

Also in this issue

Soil & Sea: reports from our producers

Learn what's happening with California Navel oranges, a virus infecting cherry trees, shrimping in Lousiana, and more.

News bites, March 2012

Fair labor certified farms, GMO bourbon, Non-GMO sales growing fast, and more

Coffee rediscovered

All coffee at PCC is organic, fairly traded, shade-grown, and Northwest-roasted. We’re excited to share the great quality of our brew and we’d love you to try it — stop by our coffee bars for a small drip coffee for just 50 cents all month! If you make your own at home, try any of these six brands, in packages or bulk.