October 9, 2006.
E. coli: Is There a Cover-up of Poor Decisions on the Type of Water Used for Irrigation of Croplands in the
Second of Two Articles
By Frank Pecarich
Retired Soil Scientist
I am one of the last to cry "cover-up in government" but sometimes the evidence seems overwhelming. For weeks now
the US has been suffering one of the worse outbreaks of E. coli in our food stream in history. This event centered on
spinach grown in Monterey County. On September 8 it started when Wisconsin reported that there was a problem to the
CDC and it was on September 14 that the FDA issued an alert asking Americans to shun spinach.
As we watched this repeat of previous E.coli contaminations unfold, there was a distinct sense of deja vu. By now all
have now read that there have been 20 such cases in the last decade and an FDA official recently said that we
probably could expect a 21st case. This is the ninth outbreak that has been traced to the Salinas Valley.
A major concern is the fact that Monterey County since at least 1998 has been irrigating 12,000 acres of edible food
crops with tertiary treated sewage effluent water in their $78 million Castroville Sea Water Intrusion Project. The
Monterey County officials, including their local Congressman, have been claiming that their tertiary treated sewage
effluent is safe to use as irrigation water and has been fully tested. As they tap-dance and send out this "no-worry"
message, much of the regulatory and scientific world looks on in wonderment.
Other than in Santa Rosa, California, which recently started irrigating about 6000 acres of crops with municipal
sanitation system sewage effluent, it is probable that no other governmental entity in the US uses sewage effluent to
irrigate contamination-vulnerable crops like spinach and lettuce. Even Nevada, well known to appreciate gambling,
would not gamble on the safety of their food supply. A few years ago even Nevada instituted a prohibition on using
effluent to irrigate contamination prone food crops and like most sensible people limited the use of effluent water to golf
courses and the like. Canada, realizing that the United States was using effluent on exported vegetables recently
proposed regulations that will not allow the importation of produce that has been irrigated with sewage treatment plant
effluent to be sold as 'certified organic' in Canada.
While all this has been going on, inspectors from government agencies have been combing the fields in Monterey
County looking like Junior Inspector Closeaus. It's as if the FDA and others never picked up a research study as the
evidence is compelling that using effluent to irrigate edible crops, certainly tender leafy green vegetables, is a very bad
Since the government officials cannot seem to find the truth, let's – like the Little Red Hen – do it ourselves. We can
start with the 2005 interim research report of the august andhighly acclaimed Agricultural Research Service which is the
primary research branch of the USDA. In their report entitled "Groundwater Recharge and Wastewater Irrigation" to
Protect Crops and Groundwater, the soil scientist researchers were unequivocal in their conclusion that E. coli was
present in treated effluent that passed through pipelines on its way to the point of irrigation. Specifically they said, "this
research established that although the reclaimed water met EPA standards for irrigation at the treatment plant, there is
great potential for bacterial re-growth during transport that could place the water out of compliance at the point of
The USDA scientists went on to say, "this work illustrated the critical need to understand the environmental fate of
microorganisms and the potential for bacterial re-growth in reclaimed water used for crop rotation so that future
problems of food and groundwater contamination via wastewater irrigation can be prevented". Because the USDA study
emphasized the E. coli contamination potential in the pipelines, it should be noted that Monterey County's pipeline
system to deliver this treated sewage effluent to farmland is forty five miles in total length. What the USDA ARS 2005
report then concluded was that E. coli can get through tertiary treated water and onto cropland.
Monterey County has cited as evidence their own "homegrown" studies that basically ended in 1987. They
used these studies to justify their proceeding with their recycled effluent-food crop irrigation efforts.
One of the key pieces of research we have looked at is the aerosol study that proved that irrigation water spraying
techniques (aerosol) would indeed transmit E.coli and other bacteria-pathogens to the plant and soil. This is the work
by Ethan B. Solomon, Hoan-Jen Pang and Karl R. Matthews. That study was completed in 1987, the same year
Monterey County finished theirs and from my reading, concluded the opposite from Monterey County which concluded
that aerosol spray irrigation tests they performed were safe. At this point we might conclude that they may have not
known about the Solomon, Hoan-Jen Pang and Karl Mathews work as they were parallel in time to each other.
But that "out" for Monterey County goes away when we realize that conclusive evidence existed prior to
1987 in the form of two journal published studies.
One of the studies I will refer to as the H. T. Bausum, S. A. Schaub, K. F. Kenyon and M. J. Small research. That
research was published in 1982 in the Journal of Applied Environmental Microbiology, five years before the Monterey
study ended. The researchers found that in the aerosol, both dispersal and downwind migration occurred.
The aerosol (irrigation spray) contained bacteria and tracer bacteriophage and treated and untreated water was tested.
They found that both survived although there was a difference between bacteria and bacteriophage survival.
Specifically they said, "chlorination reduced wastewater bacterial levels 99.97% and reduced aerosol concentrations to
near background levels; coliphage f2 was reduced only 95.4% in the chlorinated effluent and was readily measured 137
m (approximately 535 feet) downwind." May I point out that 535 feet is almost the length of two football fields.
In my reading of the Monterey County sponsored study, they were clear to point out that they tested irrigation water
spraying at night since much of the irrigation there is accomplished that way. Monterey concluded in their study that
there was no problem. The above referenced published study however discovered not only was there transport of
pathogens at night but that "Downwind microbial aerosol levels were somewhat enhanced by nighttime conditions.
Then I looked at the other two studies. In 1978 -- nine years before the Monterey study concluded -- Appl Environ
Microbiol. 1978 February; 35(2): 290-296), B. Teltsch and E. Katzenelson -- studied "the relationship between bacterial
concentrations in wastewater used for spray irrigation and in the air". They found that "aerosolized coliforms were
detected when their concentration was 10(3)/ml or more in the wastewater. Relative humidity and solar irradiation
appeared to affect viable bacteria in the air; a positive correlation was found between relative humidity and the number
of aerosolized bacteria." Moreover, they clearly state that "During night irrigation, up to 10 times more aerosolized
bacteria were detected than with day irrigation." (Remember that the Monterey County study found no problem) Wind
velocity did not play an important role in the survival of aerosolized bacteria and Echovirus 7 was found in air samples
up to 130 feet away from the irrigation sprinkler source.
The third study was published in 2002 by E.B. Solomon, C.J. Potenski and K.R. Matthews and published in the Journal
of Food Protection, Volume 65, Number 4, 1 April 2002, pp. 673-676(4). They specifically demonstrated the
transmission of Escherichia coli O157:H7 to lettuce plants through spray and surface irrigation. (emphasis added)
They state, the number of plants testing positive following a single exposure to E. coli O157: H7 through spray irrigation
(29 of 32 plants) was larger than the number testing positive following surface irrigation (6 of 32 plants). E. coli O157:H7
persisted on 9 of 11 plants for 20 days following spray irrigation with contaminated water. Immersion of harvested
lettuce heads for 1 min in a 200 ppm chlorine solution did not eliminate all E. coli O157:H7 cells. (emphasis added)
They conclude their study with this statement "The results of this study suggest that regardless of the irrigation method
used, crops can become contaminated; therefore, the irrigation of food crops with water of unknown microbial quality
should be avoided."
OK, it appears to me that the evidence that irrigating edible crops, certainly crops like lettuce and spinach
is a bad, bad -- did I say bad? -- idea.
I think that not only is there "a smoking gun", authentic researchers have found the bullet. At the very least, Monterey
County appears to be practicing some very bad science and is, at the very least, guilty of inadequate research. This is
particularly damming and egregious when you realize their mistakes may have cost people their lives. You'd think that
even Monterey Congressman Sam Farr with his degree in Biology could understand this.
As I said when I started, is there a "cover-up" in Monterey County? Why aren't officials dealing with this
overwhelming and ample evidence?
Frank Pecarich retired from the Washington, D.C. headquarters of the US Bureau of Reclamation in 1987. During his
26 year federal career he worked as a soil scientist with the USDA on the now- published Soil Survey for Monterey
County. He lives in Ventura County.
An informational hearing is scheduled for Wednesday, October 11, 2006 before the California State Senate
Governmental Organization Committee that is titled "Unraveling the e.coli outbreak: Are state emergency response
systems prepared for outbreaks of foodborne illnesses?" Perhaps the state should be asking other questions as well.