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use of compost as an absorbant


Edo McGowan <[log in to unmask]>


IOBB E-Seminar: Biodegradation of Lubricating oil contaminated soil (08-31 May)" <[log in to unmask]>


Mon, 22 May 2006 16:26:17 +0000





text/plain (1 lines)

To: Jackie Foo
Re: Suggestion for using engineered microbes or sewer sludge as adsorbant
and then feed stock for composting oil spills.
Fm: Dr Edo McGowan

SUBJECT: "IOBB E-Seminar: Biodegradation of Lubricating oil contaminated
soil (08-31 May)" <[log in to unmask]>
Sent : May 22, 2006 12:45:30 PM
To : [log in to unmask]
Subject : [BIODEGRADATION] DIGEST 3.3. Discussion with Kenneth Yongabi (CM)
et al.

Jackie---some time ago, I think it was on this list serve, there was some
discussion of spreading or incorporating sewer sludge into land were there
had been oil spills. While at first glance this seems like a plausible
solution to a process that would mix two undesirables into a viable solution
to a problem, it is not without side effects such as the spread of
antibiotic resistance, hence public health implications.

Also with incorporation of engineered microbes, there may accompanying
spread of antibiotic resistance from the methods used in the engineering
processes that develop these microbes. In this latter case, antibiotic
resistant sections of genetic material are incorporated into the microbe’s
structure. These organisms can then be selected out because they are now
resistant to an antibiotic challenge, but the markers are left within the
final product.

Exposure to heavy metals and toxins for example, will also select for
resistance, and this resistance can cross to that capable of supplying
resistance to antibiotics. The cellular machinery developed for one is
similar to that needed for the other.

Recent articles in the press have noted that there is the development of
“superbugs”, i.e. germs or pathogens that have become resistant to even the
most potent currently available antibiotic. This may bring in an era where
infections are unstoppable. This thought is not new and this same idea was
introduced to the U.S. Congress by the World Health Organization’s head of
infectious disease several years ago. The WHO has for some time noted that
antibiotic resistance amongst these superbugs or professional pathogens has
been rapidly increasing and has now reached a global crisis. This is
actually a preparedness issue, especially if there is a major infectious
disease epidemic.

As to antibiotic resistance, the medical community may be tuned in, the
average citizen is not, especially where health care systems are
oversubscribed to non-existent as in many of the developing nations. In this
case there is no preparedness. Lets look at some reasons for the development
of supebugs and their antibiotic resistance. In scientific and medical
circles, much of the underlying cause is well known but this information
fails to reach the average citizen. Thus citizens are unable to prepare.

Two decades ago, superbugs were mainly confined to hospitals and other
facilities where large numbers of very sick people were maintained on
antibiotics. The fecal material and urine were often merely flushed into the
local sewer and thus enter sewer works in large numbers. A very good
coverage of this is found within the writings of Vikrant Chitnis of India.
These super bugs or professional pathogens are now emerging outside of the
hospital and are found increasingly within the local communities across this
and other nations. This problem is augmented by over prescribing or over use
of antibiotics, especially for viral infections since antibiotics have
essentially no effect on viruses. In many countries, there is no need for a
doctor’s prescription as one can just go to the local pharmacy and buy what
is felt to be needed. Additionally, many drug manufacturers are setting up
business in countries where there are lax environmental regulations. Studies
on discharge to rivers down stream from such plants have often found
astonishingly large numbers of highly resistant organisms. Another reason we
are seeing the spread of antibiotic resistance is the excessive use of drugs
within feeds used to raise food-animals. This is seen within these large
operations where antibiotics are used not for disease control but merely for
rapid weight gain. These drugs are added to feed mixes in small but constant
amounts. This creates antibiotic resistance, which is found in the manure
and also in the finished raw product. The derived product carrys these
resistant microbes and the resistant pathogens are later transferred to the
consumer, usually by heavily contaminating the kitchen surfaces. Once thus
contaminated, these surfaces are extremely hard to disinfect.

Another way for the spread of antibiotic resistance, but seldom discussed,
is the inadequate treatment of sewage. As now operated, sewer plants across
the world’s nations are manufacturing billions of antibiotic resistant
pathogens and discharging them into the environment.

Part of this problem accrues from people in the more affluent nations
flushing unused and dated antibiotics into the sewer.

Part of the excess flushing of antibiotics is also from nursing homes, at
least in the United States. In the U.S. the federal Drug Enforcement
Administration, mandates that dated and unused drugs to be dumped into the
toilet. This adds very impressive volumes of unused and dated drugs into the
toilets each year, which wind up in the sewer works. The problem is that
sewer plants were never designed to deal with these inputs.

Sewer plant designs have been recently under review for just such reasons
but unfortunately the main agency responsible for their operation in the
United States, for example, is the U.S. EPA with demonstrably poor staffing
in the areas of emerging and communicable disease. The EPA has steadfastly
refused to seriously look into this issue, especially the issue of
antibiotic resistance.

As the sewage is processed from the moment it enters a treatment plant and
then courses through the sewer works, there is increased survival pressure
placed on bacteria and other pathogens. In response to this increased
selective pressure, the microbes utilize all their acquired skills
attempting to survive. Some are amazingly gifted in this area, yet others
can freely share their genetic information with those that are totally
unrelated. The end result is that those who survive, and there are billions
of them, are now far more potent and far more resistant than when they first
arrived at the sewer plant. Most wind up in the sewer sludge (now termed
biosolids because it sounds better) which is then applied to our farmlands.

In 2002, the National Academy of Sciences produced a major report on the
land application of sewer sludge, the solids that are separated from the
discharged wastewater. That report admonished the U.S. EPA to look at sewage
generated antibiotic resistance. Most of this sewer sludge, classified
technically as hazardous waste, is dumped on agricultural lands or sprayed
(top-dressed) onto pasture lands. The controls over what can be raised on
this land or when the animals can be returned are presumed to be well
addressed within the EPA regulations. Unfortunately, there is
characteristically poor compliance and the regulations are often flaunted.
Worse, in the U.S. these regulations apply only to those spreading the
sludge but not the farmer upon whose land the material is applied----a big
loophole. Recognizing this flaw some of the major processed foods and canned
goods manufacturers in the U.S. refuse to allow product raised on sludge
applied lands to be used in their brands.

As to the preparedness issue, sewer sludge and sewer effluent are major
transport mechanisms for disease. The following example may help the reader
appreciate all this. In Toronto, there was a recent major out-break of SARS.
The death rates were astonishingly high and the whole of Toronto was placed
under strict public health quarantine. The economic impact was thus
devastating. Health care workers in contact with patients died along with
their patients. The people and their movements were carefully followed by
the health authorities. The epidemic’s quarantine was finally stopped and
this was now believed to have been premature based on business pressures
against the health authority. The health authority released statements that
all was well. The second epidemic of SARS then promptly broke out and now
people and their movements were really tightly controlled.

SARS is transmitted by sewage and air droplets. When a toilet is flushed, an
astonishingly high level of aerosolized material escapes, especially with
the new air-assisted toilets. No one was apparently aware of this situation
although there are several reports in the literature discussing this.
Further, as an easily aerosolized disease organism, the virus, once flushed
entered the local sewer plants. Sewer plants have high rates of aerosol
generation. From these plants the wastewater containing viable SARS virus
was sent to the lakes and the sludge was transported across the U.S border
to Michigan to be used on agricultural areas. No one thought the worse of
any of this, actually these pathways were not even considered by the

Thus when engineered microbes or sewer sludge are offered for remediation,
there is a need to look to the wider impacts from such activities. I doubt
that much of this is apparent to planning and policy-makers or elected
officials. Nonetheless, without a better perspective on how antibiotic
resistance and disease is passed around, the implications addressed above
for preparedness---or more accurately the apparent lack of preparedness and
thus public health implications, the citizens of a community may not be
being well served. Without further knowledge, it seems it would be reckless
to continue the current situation, absent a through analysis of how sewer
plant operations or how the use of engineered microbes may impact currently
emerging infectious diseases and antibiotic resistance.

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