- Hello Jeff - This dated July 13, 2008 yet, we talked
about this on your program MANY YEARS ago! I even remember saying
I was worried about prions spreading via crops.
-
- "...(prions) are not degraded by standard wastewater
decontamination and can end up in fertilizers, potentially contaminating
crops."
-
- This article also carries the same lame expert statements,
such as "It is unlikely the prions would be guzzled in treated tap
water, expert says." Oh, really? I would like to ask the EXPERT
why wouldn't prions find their way into treated drinking water?
-
- And then there was this statement:
-
-
- "...essentially no risk to human health," said
David Taylor, director of special projects with the Madison Metropolitan
Sewerage District.
-
- "ESSENTIALLY?" NO RISK to HUMAN HEALTH? Huh??
-
- Jeff, I must say that people first heard about this possibility
on (guess where?) The Rense Program and they heard it many years ago.
Now we have scientists saying that prions can survive standard wastewater
decontamination. Ending up in fertilizer, which they very likely are,
is very scary and can potentially contaminate our crops with Mad Cow disease.
-
- Patty
-
- Prions Can Survive Sewage Treatment - Says
UW-Madison Study
- But Risk From Mad Cow Said Low
- By Elie Dolgin
- July 13, 2008
-
- Mad cow disease-causing prions can survive conventional
sewage treatment, according to a new study by University of Wisconsin-Madison
scientists.
-
- Prions - rogue misfolded proteins that cause mad cow
disease, chronic wasting disease, and its human equivalent, variant Creutzfeldt-
Jakob disease - are not degraded by standard wastewater decontamination
and can end up in fertilizers, potentially contaminating crops.
-
- It is unlikely the prions would be guzzled in treated
tap water, expert says.
-
- Prions never have been reported in U.S. municipal sewage.
But as a precaution, "we should keep prions out of wastewater treatment
plants," said Joel Pedersen, an environmental engineer at UW-Madison
who led the study.
-
- Prions are notoriously resilient to extreme heat, caustic
chemicals and irradiation, but it wasn't known how they would fare under
the standard barrage of treatments applied to wastewater sludge.
-
- Researchers simulated a 20-day typical wastewater treatment
regime in the laboratory on sewage taken from Madison's Nine Springs treatment
plant and then spiked it with prions from the brains of infected hamsters.
They found that a large fraction of the infectious prions survived the
ordeal, eventually joining the treatment's end-product, known as biosolids.
-
- "Should prions enter wastewater treatment plants,
they would associate with the sludge," said Pedersen, who published
his findings in the journal Environmental Science & Technology. "And
they appear to survive the further sludge treatment and digestion."
- Plenty of sources
-
- Infectious prions may enter wastewater from a number
of routes, including contaminated disposed carcasses from slaughterhouses,
animal rendering or meatpacking facilities and private game hunters.
-
- After the 2002 outbreak of chronic wasting disease in
Wisconsin, deer carcasses initially were discarded in Dane County's public
landfill. Months later, officials shifted to incineration out of fear of
prions leaching through the waste.
-
- Humans with Creutzfeldt-Jakob disease also can shed prions
in their urine, feces or blood.
-
- Laboratory facilities are another potential prion source.
In 2006, two employees at the U.S. Department of Agriculture's National
Animal Disease Center in Ames, Iowa, alleged that improperly deactivated
prions were released into the City of Ames sanitary sewer system, though
a scientific review panel later ruled that the lab's prion management protocols
were acceptable.
-
- These findings cast doubt on the safety of biosolids,
Pedersen said, though he noted that the water effluent was clean and prion-free.
-
- Biosolids generally are thought to lack human pathogens
and to be safe for agricultural applications. The Milwaukee Metropolitan
Sewerage District makes a fertilizer called Milorganite from its Jones
Island treatment plant's biosolids. Madison makes its own biosolids fertilizer,
called Metrogro.
-
- "We're looking at this research and asking what
we can do to improve our systems," said Jeff Spence, marketing director
for Milorganite. "Based on the findings, there's little or no risk
in regard to these rogue proteins as it relates to biosolids."
- Little risk seen
-
- Between the low prevalence of prion diseases and the
low probability of prions surviving to enter landfill leachate, however,
there was "essentially no risk" to human health, said David Taylor,
director of special projects with the Madison Metropolitan Sewerage District.
-
- "There has to be an exposure route," he said.
"When you look at the potential pathways and occurrences of these
kinds of (prion diseases), it just doesn't suggest that there would be
a problem."
-
- Todd Williams, an engineer with CH2M Hill in Richmond,
Va., and the vice-chair of the Water Environment Federation's residual
and biosolids committee, said that the researchers took "a quantum
leap in their conclusions" in scaling up from a small laboratory-based
study to what might happen in the real world.
-
- "Any kind of digestion activity would be on such
a small scale," said Williams, "that I question whether it would
have the same concentrations of ammonia and methane gas," both of
which could help break down prions.
-
- Since prions were restricted to the biosolids and not
the water, the study "gives better confidence that (prions) could
be sequestered in matter associated with solid materials," and potentially
removed, said Fran Kremer, a senior science adviser for the National Risk
Management Research Laboratory of the Environmental Protection Agency,
which partially funded the study.
-
- She noted, however, that the prion concentrations tested
were "higher than what we would anticipate to come into wastewater
treatment plants," and that lower prion levels might not survive standard
treatment.
-
- edolgin@journalsentinel.com
-
- Patricia A. Doyle DVM, PhD
- Bus Admin, Tropical Agricultural Economics
- Univ of West Indies
-
-
- Please visit my "Emerging Diseases" message
board at:
- http://www.emergingdisease.org/phpbb/index.php
- Also my new website:
- http://drpdoyle.tripod.com/
- Zhan le Devlesa tai sastimasa
- Go with God and in Good Health
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