Low-risk landscaping: It's time to turf the toxins

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Low-risk landscaping: It's time to turf the toxins

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Here in the rural outskirts of Ottawa, I'm delighted to finally see yellow

peeking through the snow in the sunshine. Sure, it's just our newspaper box,

but can crocuses, daffodils and dandelions be far behind?

 

Not everyone shares my joy with all flowers. Many people maintain gorgeous

lawns by optimizing the conditions for growing grass and letting the plants

and insects fight it out. With good agronomy in your corner, the grass will

win. But others feel that synthetic pesticides are needed to maintain their

sward. That option may end soon, if the provincial government passes

legislation

to ensure that only least-toxic options are available for sale and use in

Ontario.

 

Many doctors and researchers, including the Ontario College of Family

Physicians, the Children's Hospital of Eastern Ontario, the chair of the

Canadian

Leukemia Studies Group, a past president of the Canadian Paediatric Society

and hundreds of others, have looked at the pesticides commonly used in

landscaping. They say the risk is not worth it for a cheap, quick way to

maintain

turf. Pesticides are persuasively linked to birth defects and genetic damage.

They harm the nervous system, the immune system and just about every other

system that keeps us ticking. The fetus may be irrevocably harmed before birth;

children playing on the floor or ground, with their immature organs and

propensity for putting everything in their mouths, are particularly at risk.

 

Purveyors of pesticides protest that the federal regulator, the Pest

Management Regulatory Agency, rigorously studies these chemicals. We are told

that

pesticides do not pose an unacceptable risk, and that the " best science "

should rule the day.

 

But let us look at the science behind the registration of pesticides used

for landscaping. The PMRA does not consider thousands of studies investigating

the health effects of pesticides. Indeed, with no epidemiologist or medical

doctor on staff, the PMRA is ill-equipped to assess human studies. The

pesticide company supplies most data, from density and solubility to efficacy

and

environmental effects. Key is information about the doses at which laboratory

animals — generally, genetically identical rodents — experience acute and

chronic harm.

 

Rats and mice have genes for detoxification of toxic chemicals that don't

exist in people. Genetic researchers say this has implications for

pharmaceutical and toxicology research. This is layered on enormous differences

in

abilities to metabolize pesticides, amongst humans at various ages and stages,

with

differing diets, medications, co-morbidities and histories of other

exposures.

 

Animal experiments are meant to determine a level of " no observable adverse

effect. " Sometimes they find a dose that apparently doesn't bother the

animals. Sometimes all doses cause harm, so the scientists guess what dose

would

not cause harm — perhaps a third of the lowest dose tested. Mathematical

models

help to predict the dosage people would be exposed to when using the

chemical, or living nearby. This is as far as science can take the regulators.

 

The next step is to determine whether there is " no unacceptable risk " of

harm. The single-chemical dose that was found or presumed to be all right for

the lab animals is compared to how much people would breathe in, ingest and

absorb through their skin. " Acceptability of risk " is not a question that

science can answer, so arbitrary values have been set for these comparisons. If

the

chemical squeaks under this regulatory ratio, it can be registered.

 

With this system, the allowable risk is constant, regardless of the benefit.

Many believe that the benefit of a weed-free lawn cannot balance even a

small risk of lifelong impairment or malignancy, especially when more benign

methods will successfully establish and maintain a beautiful landscape.

 

Prominent pesticide researchers who have previously asserted that pesticides

do not definitively cause harm (as opposed to pesticides definitely not

causing harm) now call for more comprehensive assessment of risks.

 

Comprehensive assessment is not easy — these products are complicated. They

contain the pesticide itself, plus contaminants, breakdown products and other

ingredients. One common contaminant is a form of dioxin that is not

rigorously regulated — it suppresses the immune system as strongly as the

most toxic

of all dioxins (which is severely regulated). A common insecticide may break

down into a persistent toxin.

 

Could all of these chemicals cause chronic disease? Pesticides are linked to

cancers such as leukemia, brain tumours, neuroblastoma and lymphoma

(particularly the genetic subset of non-Hodgkin lymphoma that is increasing

most

rapidly in North America). Other conditions such as asthma, allergies,

neurological and endocrine conditions and environmental sensitivities are

increasingly

prevalent, draining the health-care system and society as a whole.

 

Chemicals are hard to avoid. Pesticides don't stay where you put them, as

people drinking groundwater are keenly aware. Children may be exposed to much

more pesticide tracked and blown into the house than they do from food and

water. The only answer is to keep the chemicals out of the neighbourhood.

 

Ontario's legislation would fill gaps left by the federal government. It

would recognize that for landscaping, where many vulnerable people are exposed,

the risks highlighted by the medical community outweigh the benefits.

 

Sweden has all-party support for the goal of a " non-toxic environment "

within a generation. Ontario's children deserve no less. Least-toxic

landscaping

is one of the easiest, effective steps we can take toward this goal.

 

Meg Sears is adjunct investigator for the Children's Hospital of Eastern

Ontario Research Institute in Ottawa.