Postings to Composting Council discussion group in 2006 on issue of infectious human and animal prions in both Class A and Class B sewage sludge biosolids, with particular regard to the fact that EPA pathogen reduction measures under Part 503 do NOT inactivate prions… this is of particular concern because the US EPA is promoting top dressing of sewage sludge biosolids on hay fields, grazing lands, dairy pastures, where cattle ingest soil and sludge with their fodder. – and on ballfields, playgrounds and home flower and vegetable gardens.
Therefore, the potential risks of human and animal prions in both Class B and Class A sludge biosolids should be fully evaluated without delay.
I apologise in advance if I have missed something in the previous exchanges, but is anyone saying they have evidence of prions surviving modern waste water treatment processes?
Prions are proteins, WWTWs rely on microbes to mineralise the various organic (and inorganic) wastes in the water, surely prions make very tasty food for the organisms which treat the water? -so how would they survive?
Waste Minimisation Officer
01772 533 831
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—– Original Message —–
To: COMPOSTING COUNCIL
Sent: Wednesday, April 19, 2006 3:47 PM
Subject: Prion survival in waste water treatment?
The US Environmental Protection Agency, says wastewater/sewage treatment does not inactivate prions:
“1. CRITICAL ISSUE: We are currently prohibiting the discharge of untreated, potentially prion-contaminated wastes to POTWs. Typical treatment and disinfection processes used by non-domestic users and those used at Publicly Owned Treatment Works (POTW) do not deactivate prions. Prions will pass through the POTW as a pollutant to be released into receiving waters and concentrated in biosolids. Biosolids are the solids produced by POTWs and typically land applied to food and non-food (grazing) crops.” (EPA Region 8, May 2005)
U. S. Dept. of Agriculture: “Bovine spongiform encephalopathy (BSE), or “mad cow disease” can survive anaerobic digestion.”
University of Guelph, Toronto, Canada, says temperatures in excess of 1400 F (760 C) are needed to inactivate prions:
UUO Toronto (Canada) Dept. of Health, Nov. 2004: “Given it is unlikely that the sewage treatment or pellet production processes can effectively deactivate prions, adopting measures to prevent the entry of prions into the sewer system is advisable.”
“This suggests that the pelletization process may not be the most suitable one to use for prion inactivation. It has also been noted that lipids, which are certainly likely to be present in biosolids, greatly enhances the stability of prion proteins, particularly at the lower temperatures (Appel et al, 1994).”
Dr. Paul Gale, in a May 2002 Risk Assessment prepared for UK Dept. for Environment, Food and Rural Affairs (DEFRA) states:
“Scrapie – : assumes composting and stock-piling has no effect on scrapie prions” “BSE: “Dorsal Root Ganglia (DRG) are main source of infectivity in catering waste – assumes composting has no effect on BSE agent”
“BSE and scrapie prions and C. botulinum spores are excluded because for the purposes of risk assessment they are considered not to be affected by the temperatures achievable by composting and biogas processes.”
“Model assumes that composting does not destroy any scrapie prion infectivity, and that there is no decay in the soil.”
Many other health and science experts say even composting to produce Class A sewage sludge biosolids does not inactivate prions. It is generally agreed in the scientific community that the chemical process known as alkaline hydrolysis is the most effective way to inactivate prions.
—– Original Message —–
To: COMPOSTING COUNCIL
Sent: Monday, March 20, 2006 6:04 PM
Subject: prions in sewage sludge biosolids
This is to respond to the issue raised by Dr.Rufus Chaney of prions in treated municipal sewage sludge “biosolids”.
Both risk assessments on prions in sewage sludge (Gale, et al, 2001, and Yamamoto, et al, 2006) agree: Prions from SRM (specified risk materials such as brains and spinal cords) of infected animals processed at abattoirs (slaughterhouses) may pass through drains into sewage treatment plants. The wastewater treatment process does not inactivate infectious prions and reconcentrates those prions in the treated sewage sludge “biosolids”. Spreading the sludge as fertilizer may expose animals including livestock to transmissible spongiform encephalopathies (TSEs).
However, as a basis for their conclusions, both Gale and Yamamoto rely on incorporation of the sewage sludge into the soil to dilute the infectious prions.
Gale: “For pasture land, a grazing restriction of three weeks applies and the treated sludge must be deep injected or ploughed down immediately after application.”
Yamamoto: “The level of sludge-derived fertilizer ingested by cattle was considered to be very low since the fertilizer is mixed with ground soil, … “
In the United States (US), top dressing sewage sludge “biosolids” on hay fields, dairy pastures and grazing lands is common practice. Thus, there is no incorporation to dilute the prions in the sludge.
Further, both Yamamoto and Gale consider the only prion source to be tiny amounts of Bovine Spongiform Encephalopathy (BSE) infected SRM (specified risk material) passing through drain screens and/or filters in abattoirs to the sewage plant. Neither Yamamoto nor Gale consider other sources of prions which are present here in the US including Chronic Wasting Disease (CWD) and human prions from Creutzfeldt Jakob Disease (CJD).
CWD, a transmissible infectious prion disease similar to BSE, is spreading and has infected farmed and/or wild deer and elk (and frequently both) in Montana, Wyoming, Colorado, South Dakota, Nebraska, Kansas, Oklahoma, New Mexico, Minnesota, Wisconsin, Illinois, and has moved east to West Virginia and New York Shedding of the CWD prions in feces and urine is considered a plausible route for transmission and environmental contamination. (Williams, et al 2002)
Infectious CWD prions are also found in muscle tissue. (Angers, et al 2006)
Disposal of infected CWD carcasses in landfills is common: “We want to reiterate that disposing of potentially contaminated CWD carcasses and wastes in MSWLFs (Municipal Solid Waste Landfills ) that are compliant with 40 CFR 258 standards is and remains an acceptable option.” (EPA memo, Nov. 12, 2004)
“In most instances the (landfill) leachate is transferred to a wastewater treatment plant (WWTP) for treatment.”
“Once that leachate (from landfill) reaches the wastewater treatment plant the suspended solids will be separated from the effluent. Those suspended solids will then be termed “sludge” or biosolids.”
“Land application of municipal sludge that potentially contains CWD PrP-res (prions) may result in the presence of CWD PrP-res in surface soils.” (WIDNR, 2002; EPA Reg. 8, 2005)
Prions can survive for years in soil (Brown, et al 1991). Animals can become infected from prions in soil. (Miller, et al 2004)
Human victims of Creutzfeldt Jakob Disease (CJD) are also shedding infectious prions into public sewers, to end up in both Class B sewage sludge and Class A sludge compost. Between 2 and 25% of the 4.5 million cases of Alzheimer’s Disease and senile dementia victims in the US are actually infected with sporadic CJD. (Manuelidis, et al, 1989; Boller, et al, 1989, 1995; Harrison, 1991; Teixeira, 1995; Warren, et al, 2005) creating the reality that many thousands of CJD victims are shedding infectious prions into public sewers.
Prions have been found in the blood and urine of CJD victims. (Gabizon, et al, 2001; Reichl, et al 2002).
Undertakers and medical facilities routinely discharge CJD infected blood and body fluids into public sewers. (Yale; UC Davis, CDC)
Prions can cross the intestinal barrier by riding piggyback on ferritin, a protein normally absorbed by the intestine. Because ferritin shares considerable homology across species, these data suggest that PrPSc-associated proteins, in particular ferritin, may facilitate PrPSc uptake in the intestine from distant species, leading to a carrier state in humans. (Singh, et al 2004)
“… enteric infection at early as well as later stages of (CJD) disease, and regardless of the route of agent entry, implicates potential environmental spread by fecal matter.” (Radebold, et al 2001)
Class B sewage sludge “biosolids” is expected to be pathogenic. EPA allows land applied sludge “biosolids” to contain fecal coliform up to 2 million CFU/gram. But the EPA and waste industry promote the use of “pathogen-free” Class A sludge “biosolids” compost on playgrounds, ball fields, public parks, and home flower and vegetable gardens.
“Pathogen free” is clearly not the case when the Class A sludge compost can contain infectious human and animal prions. Not only are livestock and wildlife at risk from ingesting prion infected soil and sludge, but humans, and particularly children, are especially at risk because their hand to mouth behavior results in the ingestion of dirt (Robischon, 1971; LaGoy, 1987; Binder, et al 1986; Gerba, et al 2002 ; CDC, Callahan, 2004).
The EPA guidelines and disclosures on pathogens in Class A sludge “biosolids” compost need to be revisited.
—– Original Message —–
To: COMPOSTING COUNCIL
Sent: Wednesday, March 22, 2006 4:06 PM
Subject: inactivating prions
This is to respond to Loyd Johnston’s questions regarding inactivation of prions by composting and other pathogen reduction methods.
EPA Region 8: “Common methods of waste treatment in sewage treatment plants, or publicly owned treatment works (POTWs), and septic systems, as well as landfilling and composting, are ineffective at completely inactivating TSE agents (Prusiner 1982; Bellinger-Kawahara et al. 1987; Manuelidis 1997; Taylor 2000; Taylor 2001)…”
National Renderers Assoc. response to USDA and APHIS, June 2005: “While finished compost can be spread on crop ground as fertilizer, if prions are present and the compost is used as fertilizer prions can re-enter the food chain through grazing plants and hay and straw obtained from those. Thus, composting should not be used to dispose of CWD deer and elk, sheep and goats with scrapie or cattle with BSE. Composting is especially unsuitable for specified risk materials, especially neural tissues (skull and spinal cord) encased in bones (ref.11). The indiscriminate use of composting and spreading its by-products on agricultural land is inconsistent with the FDA feed rule, would dilute its integrity and invalidate all existing BSE/TSE risk assessment models (ref.8). This is similar to what may have transpired with the CWD material, given the WIDNR disposal policy (refer to 2.3. Controlled Land Fill) was indeed implemented.”
Dr. Paul Gale, UK, DEFRA, May 2002: “BSE and scrapie prions and C. botulinum spores are excluded because for the purposes of risk assessment they are considered not to be affected by the temperatures achievable by composting and biogas processes.”
Iowa State: “Due to many unknown factors regarding the biodegradability of the prions that cause bovine spongiform encephalopathy (commonly called BSE or “mad cow” disease), composting should NOT be used for disposal of cattle suspected to have BSE.”
APHIS/USDA – Jan. 2005: Anaerobic digestion (of carcasses )… “it is necessary to use additional heat at the end of the process to fully inactivate pathogens. However, even with this, prions are not inactivated.”
University of Ottawa, Ontario, Canada: “This suggests that the pelletization process may not be the most suitable one to use for prion inactivation. It has also been noted that lipids, which are certainly likely to be present in biosolids, greatly enhances the stability of prion proteins, particularly at the lower temperatures (Appel et al, 1994).”
US EPA: “Prions are extremely resistant to inactivation by ultraviolet light, irradiation, boiling, dry heat, formaline, freezing, drying and changes in pH. Methods for inactivating prions in infected tissues or wastes include incineration at very high temperatures and alkaline hydrolysis.”
—– Original Message —–
To: COMPOSTING COUNCIL
Sent: Friday, April 14, 2006 12:05 PM
Subject: prions in soil
This is to respond to issue raised by Mr. Peregrim that prion diseases can only be spread through consumption of infected animal tissue. To the contrary, a new study confirms that soil in a pen contaminated by alimentary shedding of sick animals (urine, saliva and feces) can remain infective for up to 3 years and transmit Chronic Wasting Disease to previously healthy animals.
“Prions Adhere to Soil Minerals and Remain Infectious” Christopher J. Johnson, et al – University of Wisconsin –
The US Environmental Protection Agency (EPA) acknowledges that no sludge biosolids pathogen reduction method — including composting — inactivates infectious prions:
“CRITICAL ISSUE: We are currently prohibiting the discharge of untreated, potentially prion-contaminated wastes to POTWs. Typical treatment and disinfection processes used by non-domestic users and those used at Publicly Owned Treatment Works (POTW) do not deactivate prions. Prions will pass through the POTW as a pollutant to be released into receiving waters and concentrated in the biosolids. . Biosolids are the solids produced by POTWs and typically land applied to food and non-food (grazing) crops.” (EPA Region 8, May 2005 )
The wild card is the shedding of infectious prions in the blood, urine and feces of tens of thousands of victims of the prion disease sCreutzfeldt Jakob Disease (sCJD) [Several studies have found between 2 and 25% of the 4.5 million Alzheimer’s victims in USA actually have CJD].
Class B sludge is expected to be pathogenic. But Class A sewage sludge biosolids compost is advertised as being “pathogen free”. If it contains infectious human and animal prions — it isn’t “pathogen free” and EPA/waste industry advertising is false.
What is particularly worrisome is this statement in the U of Wisconsin study referenced above:
“Taken together, these data support the notion that PrPsc-contaminated soil may allow intraspecies TSE transmission and enhance the likelihood of spread to other species.”
—– Original Message —–
To: COMPOSTING COUNCIL
Sent: Monday, April 17, 2006 8:45 PM
Subject: prion “species barrier” and infective doses
This is to respond to waste industry claim that the “species barrier” protects from prion diseases.
“BSE has now been transmitted orally to 16 species,” (S. Dealler, 1995)
Animals which have suffered fatal prion diseases include Sheep,( Rendered sheep fed to cattle are believed to have initiated the mad cow epidemic) Goats, Cattle, Bison, Elk, Mule and white-tailed deer , Oxen, moose, domestic house cats, several species of macaques/monkeys, several species of lemurs, farmed Mink, Cougars, Cheetahs, Puma, Ocelot, Tiger, Lion, Kudu, Oryx, Eland, Nyala, Gemsbok and Ankole.
Contaminated meat and MBM feed are linked to zoo animal infections.
Pigs have been found to be susceptible to transmission of TSEs.
There is a 1999 report of three German zoo ostriches which developed TSEs after having been fed downer cattle.
Recently in Europe, two sheep and a goat have been found to be infected with BSE ( NOT scrapie) – indicating mad cow disease has again jumped species.
University of Wisconsin researchers recently released a report finding CWD prions from infected carcasses, and alimentary shedding (urine, saliva and feces), could survive in soil up to 3 years and possibly infect other species. By using flashlit photography, they found an infected CWD carcass attracted many species which could be at risk including raccoons, hawks, owls, crows, dogs, cats, coyotes, skunks, mink, foxes and opossums.
Initially, UK officials insisted the mad cow epidemic was no risk to humans. 150 human vCJD deaths later they found they were wrong.
For years, the “experts” insisted infectious prions could not be found in blood or muscle except for scrapie infected sheep and goats. Prions have since been found in blood and muscle of human vCJD and sCJD victims and in leg muscle tissue of CWD deer.
Sludge proponents claim there aren’t enough prions in sludge to constitute an infectious dose.
“Critics say that one example of outdated assumptions is the Harvard study’s assumption that a cow would have to eat 1 gram of infected material to come down with the disease. Kihm said most scientists now believe a cow would have to eat only 10 milligrams of infected material, a piece the size of a peppercorn, to catch the disease. That’s 100 times smaller than the assumption in the Harvard study. Recent British studies suggest the infectious dose could be 400 micrograms, which is 25 times smaller than 10 milligrams” (Dr. Michael Hansen) (400 micrograms = 0.0004 gram )
Prion expert Dr. John Collinge: “It’s often said that injecting prions directly into the brain of an animal is about 100,000 times more effective than feeding the same dose. That’s true when you’re within the same species, but when you’re jumping from one species to another that ratio doesn’t always hold, and the oral route may be surprisingly effective. ”
Ignoring animal sources of prions, blood, urine and feces of humans infected with sporadic Creutzfeldt Jakob Disease (sCJD) are the largest potential source of infectious prions in both Class B and Class A sewage sludge biosolids.
Between 2 and 25% of the 4.5 million cases of Alzheimer’s Disease and senile dementia victims in the US are actually infected with sporadic CJD. (Manuelidis, et al, 1989; Boller, et al, 1989, 1995; Harrison, 1991; Teixeira, 1995; Warren, et al, 2005)
These sCJD diagnoses are irrefutable because they are based on either biopsies or autopsies – not merely observation or speculation.
Under ordinary circumstances, most sCJD cases go undiagnosed. Few autopsies are done on suspected sCJD victims because the families don’t want to incur the expense. What’s the point? And the pathologist/medical examiner is reluctant to do an autopsy because he is concerned about his own risk of infection and the fact that expensivemedical instruments may have to be discarded if the case is positive.
Last year I filed a FOIA request with US EPA regarding prions in sludge. They provided a long list of the documents they were withholding from me. But even that list was instructive of the extent to which the US EPA internally considers prions in sludge a serious problem.
It is the responsibility of the US EPA – not me – to determine whatpathogens survive in both Class B and Class A sewage sludge”biosolids” which they promote for use on grazing lands, hay fields, dairy pastures, children’s ballfields and home flower and vegetable gardens.
—– Original Message —–
From: “HShields” <email@example.com>
To: “COMPOSTING COUNCIL” <firstname.lastname@example.org>
Sent: Saturday, May 06, 2006 7:49 PM
Subject: [USCC] Prions at soil surface from organic fertilizer and excreta …
The UK Spongiform Encephalopathy Advisory Committee (SEAC) forwarded a new research article this past week:
“Interactions of prion proteins with soil”, Liviana Leita, et al, Soil Biology & Biochemistry, (Elsevier) accepted November 7, 2005″
“Results clearly demonstrate that both the no infectious (PrPc) and infectious (PrPsc) forms are absorbed by all soils… The strong interaction of PrPsc with soil favors the accumulation of prions in soils, especially if amended with prion-containing organic fertilizers and/or whenever TSE-affected animal carcasses, placenta, and excreta in general are buried or laid at the soil surface.”
“In conclusion, although these results cannot precisely define the nature of the bonds between prions and soil
components, especially if they are reversible under conditions other than those tested in the present study, the apparent strength of such interactions suggests that prions can be retained, and accumulate in soil, especially if amended with prion-containing organic fertilizers and/or whenever TSE-affected animal carcasses, placenta, and excreta in general are buried or laid at the soil surface (Miller et al, 2004). If the adsorbed prions also retain their pathological activity (Brown and Gajdusek, 1991; Leita et al., unpublished results), they could represent a hazardous environmental source of infectivity, and provide a further explanation for the horizontal transmissibility of TSE forms, such as scrapie and CWD.”
Please note these Italian researchers specifically identify “organic fertilizer” and “excreta” as potential sources of prions. This European study parallels and reinforces the recent conclusions of University of Wisconsin scientists (Johnson, Pedersen, et al 2006) that prions in soil survive for long periods and may contribute to horizontal transmission of TSEs (transmissible spongiform encephalopathies) in animals.
The US Composting Council is a wide-reaching, well read forum for discussion. Last week, in response to a posting, I had a call from an oral surgeon who was concerned about dealing with medical instruments used on elderly patients who may potentially be infected with sporadic Creutzfeldt Jakob Disease (sCJD).
His concerns are well founded since between 2 and 25% of Alzheimer’s patients are actually infected with sCJD, and standard autoclaving does not inactivate infectious prions. Some experts advise discarding medical instruments used on patients who turn out to be infected with sCJD — obviously an expensive proposition.
I also received a call from a Southern California composter who questioned the accuracy of my statement that EPA approved sewage sludge pathogen reduction methods do not inactivate prions. He was concerned about top dressing his Class A sewage sludge biosolids compost on playgrounds and childrens’ ball fields. His caution is noteworthy and well justified because children with their undeveloped immune systems and hand-to-mouth (eat dirt) behavior are most at risk of infection from any pathogens, including human and animal prions, which may survive in Class A sludge biosolids. He was quite interested to learn that in June 2004, the US EPA made a $100,000 grant to University of Wisconsin researchers (Judd Aiken, Trina McMahon, Joel Pedersen, Craig Benson) to investigate the fate of prions discharged to wastewater treatment plants. In 2002, the Wisconsin Dept. of Natural Resources concluded the infectious prions pass through the sewage treatment plant and are reconcentrated in the sludge biosolids.
The US EPA recently committed to upgrading the Process Design Manual for Sludge Treatment and Disposal…
The original 26 year old document doesn’t even mention prions as a potential sludge pathogen. If the US EPA is going to continue promoting land application and top dressing of both Class B and Class A sewage sludge biosolids on hay fields, grazing lands, dairy pastures, ballfields, playgrounds and home flower and vegetable gardens, the potential risks of human and animal prions in both Class B and Class A sludge biosolids should be fully evaluated without delay.
And NOW – July 2007 – we have the shocking scientific finding by University of Wisconsin researchers (Dr. Aiken and Dr. Pedersen), operating with a $100,000 EPA grant, that prions can be up to 700 times more infectious when bound to soil! […how about the EPA approved policy of topdressing sewage sludge which may contain both human and animal prions on dairy pastures, hay fields and grazing lands?]
“Aiken agreed. “You have an infective agent that doesn’t degrade easily,” he said. “It’s not going to percolate through the soil. It’s going to bind.”
FRI., JUL 6, 2007 – 10:00 AM
Finding offers clues on CWD
By binding to a common soil mineral, the misshapen proteins that cause chronic wasting disease in deer can be as much as 700 times more infectious than exposure to the proteins alone, according to researchers at UW-Madison. The finding, by UW-Madison animal health and biomedical science professor Judd Aiken, may help explain why CWD spreads orally among Wisconsin deer even though animals in the wild are exposed to relatively low levels of the infectious proteins, called prions. Herbivores, including deer and sheep, consume a fair amount of dirt each day as they graze. They are also known to consume soil as a source of minerals. [grazing cattle are known to ingest 1 kilogram of soil a day 2.2 pounds – ]