[PEN-L:28648] The perils of trying to heal the rift

["ken hanly" <khanly@xxxxxxxxxxxxxxx>]

There is another article from the National Post dated May 20, 2002 and
entitled: Fields of sewage. New research suggests composted human waste may
not be safe for use as fertilizer by Margaret Munro.

Thousands of tonnes of fertilizer from sewage plants enrich ranchland. It
contains nutrients that are good for the soil, but also passes toxins
through cattle into the human food chain.

Ranchers insist their hay has never grown better. Golf course operators
swear it does wonders for their greens. And in Kelowna, B.C., people can
hardly flush their toilets fast enough to keep up with demand for the dark,
fragrant compost made from that city's human sewage.

"It's become quite fashionable to use it," chuckles Wilma Schellenberger,
past-president of the Kelowna Garden Club, who smothered her lawn with
compost-enriched soil.

"It came back wonderfully green," says Mrs. Schellenberger, whose flowers
are also thriving on the composted sewage the city sells for as much as
$21.50 a cubic metre.

Such talk is music to the ears of municipal officials responsible for the
human and industrial waste flushed down the country's toilets and drains.

The rivers of sewage produce mountains of sludge -- or biosolids, as
engineers prefer to call the material. The engineers like to think they have
hit on the ideal disposal scheme: Transform the sludge into fertilizers and
compost, then get farmers and gardeners to plough it back into the land.

To listen to municipal officials talk, they are turning a sow's ear (and far
worse) into a silk purse.

"It's full of nutrients that are good for the soil," says Theresa Duynstee,
biosolids recycling manager for the Greater Vancouver Regional District, who
is echoed by sludge managers across the country.

Toronto is about to start churning fertilizer pellets out of the
foul-smelling goo extracted from sewage at a new $23-million plant. In
Moncton, N.B., and dozens of other towns and cities, human sewage is finding
its way into compost and topsoil. And in Vancouver, the putrid waste that
flows into the region's newest treatment plant comes out as black, chunky
material that municipal officials have christened Nutrifor.

Close to 50,000 tonnes of the stuff is trucked into the B.C. Interior every
year and used to reclaim mine sites and enrich ranchlands. And poplar trees,
destined to be used to produce toilet paper, are thriving on
biosolid-enriched islands in the Fraser River.

Vancouver's regional government has also been busy making plans to use
Nutrifor in the city. The logic is simple: What is good for cattle and trees
is good for the gardens of folks who produce the stuff in the first place.

But a recent report from the University of British Columbia, prepared for
the province's medical-health officers, has prompted a sudden change of
plans.

The report warns that dioxins and furans might concentrate in vegetables
such as cucumbers and in cattle munching grass grown on land fertilized with
sewage biosolids. "It is recommended at this time that biosolids application
not be permitted on land used to grow plants of the cucumber family or on
grazing lands," the UBC report concludes.

The report, which was presented to waste-water specialists a few weeks ago,
shocked regional officials and managers who last year sent 45% of their
biosolids to ranches in the B.C. Interior.

"We were stunned," says Paul Kadota, head of the Vancouver region's
biosolids program, who fears his silk purse is turning back into a sow's
ear.

Given the conclusions of the UBC report, Kadota says the plan to get city
dwellers using Nutrifor as a soil enhancer has been shelved. "It's
definitely on hold ," says Kadota. And the practice of using Nutrifor on
grazing land in the B.C. Interior is up in the air. The regional government,
he says, is awaiting advice from the province's medical-health officers,
which is expected in the next few months.

"We're looking for clarity," Kadota says.

But clarity is awfully elusive in the murky world of sewage treatment and
disposal.

For every official who says biosolids are harmless, there is a critic
warning of toxins and microbial pathogens. And for every report suggesting
sludge can be safely used, there is another raising concerns.

The one thing everyone seems to agree on is that processed and composted
sludge is a huge improvement over the untreated sewage that farmers have
been using on their lands throughout the ages. Many towns and cities in
Canada still spread raw and partly treated sewage, which contains high
levels of bacteria, viruses and parasitic worms, on farmland.

Processed and composted sewage sludge is better because it is treated, often
at high temperatures, to kill pathogens.

That is not to say the stuff is clean. It can contain bacteria -- a level up
to 1,000 fecal coliforms is allowed in every gram of sludge-based fertilizer
or compost sold in Canada. And there are traces of almost every toxin one
can think of: selenium from anti-dandruff shampoos, manganese used in
additives used in gasoline, copper that leaches out of household pipes,
brominated diphenyl ethers (BDEs) from flame retardants. And perhaps most
worrisome, traces of furans and dioxins, cancer-causing toxins that can be
produced in tiny amounts by a multitude of sources ranging from textile dyes
to steel mills and hospital incinerators.

Provincial and municipal officials say the pathogens and toxins are under
control. They like to point to recycling programs that have reduced levels
of everything from the mercury flushed down dentists' sinks to paints and
dry-cleaning fluids that go straight into drains.

Sewage sludge does, however, vary considerably from one place to the next.
Not only does the stuff pouring down toilets differ from city to city, so do
treatment processes.

In Toronto processed sludge rolls over hot plates and is heated to close to
100C, forming pellets that resemble gravel. "It's hot enough to kill any
bacteria, " says Kiyoshi Oka, Toronto's senior engineer in charge of
biosolids. But pellets have their own drawbacks. They can start smouldering
if not stored or handled properly.

Toronto had hoped to be marketing and using its new fertilizer in city
gardens by now, as part of a plan to combat the stigma surrounding the tiny
pellets, Oka says. But controversy over a combustion problem with pellet
dust at a loading dock last year and regulatory problems over labeling have
delayed production. Pellet production is now slated to begin before summer.

Oka says sewage biosolids are one of the most studied materials around. And
many people would be surprised, were they to read the fine print on their
fertilizer boxes, that they are already using pellets made from sewage
sludge. Several U.S. cities, such as Milwaukee, Wisc., which has been
producing the product Milorganite for years, produce sludge fertilizers
widely used on golf courses and sold in Canada for use on home gardens.

Oka, like most people familiar with sludge treatment, insists there is no
health or environmental risk in sprinkling the sludge-based composts and
fertilizers on lawns and gardens as long as they meet limits that have been
set for pathogens and heavy metals.

But federal records show plenty of fertilizers on the market are in
violation of those limits. Inspectors from the Canadian Food Inspection
Agency (CFIA), which enforces the Fertilizers Act, tested 55 fertilizers and
composts for bacterial contamination during the past year. Of 21 products
tested for fecal coliforms, 24% had levels above the limit. And 15% of the
34 fertilizers tested for salmonella were over the limit. Fecal coliforms
and salmonella are considered "indicators" because they are such hardy
microbes. If they survive the sewage treatment process, so might more
serious pathogens.

CFIA officials refuse to name the non-compliant products. And they will
provide no details on the height of the bacterial counts. But they say the
non-compliant products were detained and returned to their producers for
further treatment or disposal.

None of which is very reassuring to people such as Dr. Coleman Rotstein,
president of the Canadian Infectious Diseases Society, who teaches at
McMaster University in Hamilton, Ont. "I am not convinced about the quality
control," says Dr. Rotstein, who would like to see more debate and study
before more pelletized or composted sewage sludge is scattering in urban
areas.

"That's a problem when you live in populated areas. Anything can happen.

"I don't think we should do this until we know it is perfectly safe," says
Dr. Rotstein, who was recently asked to serve on a committee being formed by
Toronto Public Health to review the safety of biosolids, given that city's
plan to market 25,000 tonnes of fertilizer pellets a year.

A similar exercise recently led by Kay Teschke, a professor at UBC's School
of Occupational and Environmental Hygiene, concluded spreading sludge-based
fertilizers and compost on home gardens is not a problem.

"I wouldn't hesitate to use it myself," she says.

The much bigger concern, she and her colleagues report, is using biosolids
to fertilize agricultural land.

Teschke's group dug through dozens of studies and reports from around the
world trying to determine whether biosolids could lead to problems with
dioxins and furans, which can accumulate in living tissues and have been
linked to cancer.

It is well known that sewage sludge contains trace levels -- parts per
trillion -- of dioxins and furans. But there is limited data on the fate of
the toxins once the sludge is spread around, the UBC group says in its
report prepared for the province's medical-health officers. It notes that
several studies have shown concentrations of dioxins and furans in the soil
increase measurably when biosolids are applied, and the contamination
persists over time.

There is little evidence they build up in leafy vegetables, tree fruits,
peas and beans and harvested forage crops. But experiments in which plants
were grown in soil highly contaminated with dioxins and furans have shown
the toxins can accumulate in plants of the cucumber family.

Their report stresses the "great need for further data on the relationship
between biosolids application to agricultural land." In the meantime, it
recommends against using biosolids on land used to grow plants of the
cucumber family or on grazing lands, where furans and dioxins swallowed by
cattle could end up in meat and milk.

Teschke says they are recommending the province launch a research program to
study whether dioxins and furans are being taken up in cattle grazing on
ranchland treated with Vancouver's biosolids. And to hold back any meat
until tests prove it is safe, she says.

And if the research fails to prove the material can be used safely,
Vancouver might have to come up with another use for sludge that is not
about to stop rolling out of its sewage plants.mailto:
mmunro@xxxxxxxxxxxxxxxx

"Perhaps we could make bricks out of it," Kadota says.
mmunro@xxxxxxxxxxxxxxxx

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