Is sewage fertilizer safe?
Worries grow over 'stew' of chemicals spread on farmlandJuly 12, 2008
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URBAN AFFAIRS REPORTER
Feces, urine, vomit, blood. Synthetic hormones, heart pills, antibiotics,
illicit drugs, Viagra. Bacteria, viruses, E. coli, parasites. Household
cleaners, shampoo, solvents, pesticides and traces of arsenic, mercury, cadmium,
lead, dioxins and flame retardants.
Each day, this chemical cocktail is piped from our homes, businesses and
industries to sewage plants across the province. The water is filtered and
The solid waste that remains is turned into biosolids, more commonly called
sludge. For more than 30 years, Ontario's sludge has been trucked out to
farmland for use as fertilizer.
Then in 1996, the province, which monitors sludge dispersal, increased
promotion of the nutrient-rich goo to farmers as a beneficial alternative to
chemical fertilizers. Officials insist sludge is tested and safe and that there
are no documented cases of adverse health effects when requirements are
But some rural residents who live near properties where sludge has been used
have argued for years that what ends up on fields isn't benign fertilizer, but a
"toxic stew" that's harming them and the environment.
"It takes the air out of your lungs and burns your eyes. It's nasty, nasty
stuff," said Crystal Chordis, a resident of Corbetton north of Orangeville.
Country-dwellers exposed to sludge complain of a litany of ailments including
respiratory problems, diarrhea, headaches, nausea, rashes, fatigue and
Ontario's acting chief medical officer of health, Dr. David Williams, says a
clear link to adverse health effects hasn't been established. He is satisfied
that the practice of using biosolids on farmers' fields is safe and says the
process of monitoring possible health issues is "active and ongoing."
Just what is making people ill is difficult to pin down but two things are
Firstly, what is making its way into our sewage system has changed with new
drugs and chemicals raising questions as to whether the testing and tests are
Secondly, local officials who investigate health complaints are not required
to report their findings to the province.
And while experts on both sides of the issue are mostly at odds, they agree
on the first point: There is still a lot to learn about sludge.
"A complete analytical characterization of sludge's pathogen, endotoxin and
chemical contaminant composition has never been attempted," says researcher Dr.
Rob Hale of the Virginia Institute of Marine Science. Forty per cent of the
sludge produced by Ontario's municipal sewage plants – 120,000 dry tonnes each
year spread on 15,000 hectares – is put on soil where crops are grown. The bulk
of it, which is given to farmers free, ranges in consistency from a thick liquid
to a drier cakelike form.
A plant in Windsor turns a small amount of biosolids into dried pellets for
which farmers pay about $19 a tonne. (What's not spread on farmland is burned or
sent to landfills.)
Eighty per cent of Ontario's municipalities spread sludge on agricultural
land. Last year, 13 per cent of Toronto's sludge was put on farmers' fields.
What to do with municipal sludge is nothing new and for years it was
incinerated, sent to landfills or simply dumped into the nearest Great Lake.
Diverting some of it to fields got its start in the 1970s but went into high
gear in 1996 after the Great Lakes Water Quality Agreement stiffened sewage
treatment guidelines and in turn created more sludge.
Since then, the province has pushed so-called land application as a safe
option for municipalities struggling to deal with fast-filling landfills and a
U.S. border that is slowly closing to Ontario's waste.
But the provincial regulations governing testing and application were last
updated in 1998 and now a whole new range of chemical compounds is turning up in
our sewer systems. Many of these, such as pharmaceuticals and personal care
products, simply aren't tested for because there are few labs that can do that
kind of analysis, no accepted methodology, and no benchmarks to say what's safe.
Yet, the lack of epidemiological studies means it cannot be determined
whether sludge is making people sick. That has prompted a call for more research
from Toronto toxicologist Dr. Anne Mildon.
"It's cause and effect," says Mildon, who treats several patients who believe
sludge made them ill. "I'm too good a scientist to say, `Yes, this is definitely
it,' but it's very likely."
Several major food companies are not taking any chances. Del Monte, Campbell
Soup and Gerber won't use food that has been fertilized with biosolids. Not
enough is known about biosolids, they say.
Del Monte developed its no-biosolids policy in the early '80s, concerned that
trace amounts of heavy metals and chemicals might find their way into the food
chain. The other firms have also had long-standing policies.
Mildon, who led a provincial task force on radioactive waste in Port Hope
during the 1990s, says the provincial government has been in a "state of denial"
and has failed miserably to address public health concerns about sludge.
Her concerns are echoed here and around the world.
In parts of the United States, several deaths have been linked to sludge
exposure. In Ontario, several citizens' group including those in Prince Edward
County and near Orangeville have succeeded in halting or restricting
Sweden, Switzerland, France and Holland are among the countries that have
either banned or introduced tougher standards on the use of biosolids as
fertilizer. Instead, they are burning more of it in energy-from-waste
Since 2002, Ellen Harrison, recently retired director of the Waste Management
Institute, a research and training branch of Cornell University in Ithaca, N.Y.,
has argued for a ban on sludge application. She expresses frustration over the
paucity of health studies.
One of the few is a recently published report by researchers from the
University of Toledo in Ohio, which found a significant increase in problems
such as abdominal bloating, jaundice and weight loss among residents exposed to
The 2005 study surveyed 613 people over one month and researchers also noted
an increased risk for respiratory, gastrointestinal and some chronic diseases
such as multiple sclerosis. Four hundred and thirty-seven of the people surveyed
lived within 1.6 kilometres of fields treated with biosolids, 176 lived further
In 2002, under pressure from concerned residents, the City of Ottawa
commissioned a review on the health and safety of spreading biosolids.
Struck by the lack of medical information, the consultants concluded that a
"surveillance system for monitoring health effects from biosolids does not
appear to exist in any jurisdiction.
"While anecdotal cases are occasionally reported by the news media, few of
these are investigated by trained teams of agronomists, engineers,
toxicologists, microbiologists or public health professionals, let alone make
their way into peer-reviewed research literature," the final report read.
After a two-year moratorium, sludge-spreading resumed in Ottawa.
Today, provincial officials do not know how many health complaints have been
reported or how many investigations have been done in Ontario.
(Complicating the issue is people who experience illnesses they believe are
related to sludge often are afraid to report anything because it would mean
blowing the whistle on neighbours they value as friends and helping hands.)
Here's how the complaint system works in Ontario: Anyone with a health
complaint they believe is related to biosolid-spreading should report it to
their local health unit. The local medical officer of health investigates the
complaint to determine whether a health hazard exists.
He or she notifies and consults with the environment ministry, which assesses
if the sludge was applied according to provincially set regulations and
standards. The medical officer of health also consults with the agriculture
ministry. If provincial guidelines were violated or a health hazard exists the
environment ministry can order the problem fixed and may lay charges.
After investigating, the health officer sends a written report to the
complainant but there is no requirement to send the report to anyone at the
Communication is at the discretion of the local health units, said David
Jensen, a spokesperson for the health ministry. He added that Williams, the
acting chief medical health officer, is required by law to keep himself informed
"on matters related to occupational and environmental health."
Williams said he expects local medical officers of health to keep him in the
loop but "there is no requirement by law to tell me everything they're doing."
Cornell's Harrison finds it "appalling" that Ontario does not catalogue
complaints or do a thorough and immediate investigation. When a sludge-related
health issue is suspected, she says, an investigation should be launched at the
source, as it would be in an outbreak of food-borne disease.
Harrison had some advice for politicians: "If it is possible to err on the
side of caution, do it: Put in place a system for complaints investigation, and
(don't) continue with a `head in the sand' approach that everything is all