We’re all aware of the importance of the
natural environment, and that each of us has
a responsibility to protect it. The widespread
use of pesticides by farmers, industry, the
pest control industry, and the general public
provides many possible sources for pesticides
to enter into the environment. In the 50's
and 60's, environmental contamination from
the use of pesticides was unexpected. It was
thought that pesticides in the natural environment
would either break down or be in such small
quantities that there would be no risks to
the environment. Ironically, the chemicals
designed to increase food production and improve
our standard of living, were harming our environment.
Most modern pesticides degrade readily when
exposed to sunlight or microorganisms in the
soil. However misuse or misapplication can
allow pesticides to drift to non target sites
or to move in surface run off or leach into
ground water. Wells and water courses have
been contaminated. Non-target plants and animals
have been affected. Trace levels of persistent
pesticides have been detected north of the
Arctic circle and south of the Antarctic circle
as a result of air currents moving and depositing
soil particles. Most of these persistent pesticides,
such as DDT, have been banned from use in
Canada since the mid 1970's. Because farmers
own a large portion of Ontario’s private
lands, they have a unique responsibility to
protect the environment on and around the
farm and around their community. Keep in mind,
that farmers and their families are living
in the same areas where they apply pesticides,
and it is in their own best interest to take
this responsibility seriously. Neglecting
to do so means risking the health of your
family and your community. So, what is the
Environmental Risk of using pesticides? 
Each time you apply a pesticide on your farm,
a number of things may happen to that pesticide.
The pesticide may be taken up by plants, evaporated
into the atmosphere, carried off as drift,
or ingested by insects, worms and microorganisms.
The pesticide may adhere to soil particles
or be dissolved in irrigation or rain water.
There is always some risk to the environment.
The degree of risk depends upon four factors,
how long the pesticide remains active in the
environment – PERSISTENCE, how easily the
pesticide can move from where it is applied
– MOBILITY, how toxic the pesticide is to
organisms other than the pest - NONTARGET
TOXICITY and how much of that pesticide is
used in the environment - VOLUME of USE. Environmental
Risk can be summarized in this equation. Environmental
Risk equals Persistence times Mobility times
Nontarget Toxicity times Volume of Use. Environmental
Risk is minimized when any of these risk factors
is close to zero. The physical and chemical
properties of pesticides influence their environmental
risk. By considering these properties before
you use a pesticide, you will be able to maximize
the pest control and minimize any adverse
environmental affects pesticides may have
on your farm, your community and far reaching
areas. 
First, let’s review six properties of pesticides
that can affect their behaviour in the environment.
These are the properties of pesticides that
can cause short or long term environmental
affects on your farm. Pesticides eventually
break down in the environment. This is called
DEGRADATION. How fast this happens depends
on the pesticide and the environmental conditions
on your farm. The pesticides are broken down
or degraded by soil microorganisms, by chemical
reactions and sunlight. If the soil is warm
and moist, microbes use the pesticide molecules
as a food source and turn them into harmless
molecules such as carbon dioxide and water.
Pesticides that do not break down quickly
are called persistent pesticides. Persistent
pesticides include chlordane and DDT both
of which are no longer used and are banned
in Ontario. However, chlordane still remains
in some soils from applications made in the
60’s and 70's. Most chlordane is lost from
soil through evaporation. Persistence is greater
in heavy clay or organic soil than in sandy
soil. Many farm wells, particularly in corn
growing areas, contain residues of atrazine.
Atrazine, has been found in surface and ground
water all over Ontario. Before you plan to
use a pesticide, find out how persistent the
pesticide is. If there is another product
that will do as good a job but is less persistent,
choose it instead. 
Pesticides may accumulate or build up in body
tissues or body fat of man and animals. This
is called BIO-ACCUMULATION. If the body has
no way of getting rid of the pesticide, every
time the organism is exposed to the pesticide,
more is stored in the fat cells. In the 1940's,
scientists found residues of the man-made
chlorinated hydrocarbon pesticide, DDT, in
human fat. This was the cause for much alarm.
Many chlorinated hydrocarbon pesticides do
not degrade readily, and because they accumulate
in fat, they moved from one creature to another
upward in the food chain all the way to us.
Small levels of these types of pesticides
in water and soil can magnify into a significant
hazard to predators at the top of the food
chain. Pesticides may change into a vapour
when exposed to air, or evaporate. This is
called VOLATILITY. Once a pesticide evaporates,
it can travel for miles, often hitchhiking
on dust particles in the air. The volatile
and persistent pesticide toxaphene has been
found in fish in the Great Lakes and in the
lakes of the Canadian Arctic, having travelled
unchanged for long distances in the air from
the southern US where it was used on cotton
until it was banned in 1982. The volatility
of the herbicide trifuralin, can be reduced
by the incorporation of the pesticide into
soil. Check the product label for ways to
apply pesticides to reduce volatility. Pesticides
can bind onto soil particles and organic matter.
This is called- ADSORPTION. The way a pesticide
binds to the surface of the soil particle
is similar to magnetic attraction. Soils that
are high in organic matter or clay are the
most adsorptive. These tightly bound pesticides
will be less likely to leach with water, that
is, to move downward through the soil, and
will be less likely to reach ground water.
However, a pesticide adsorbed tightly to the
soil may move with soil particles eroded by
wind or by water and not be so readily degraded
by soil microorganisms. The amount of organic
matter in the soil may be increased by the
addition of manure and the incorporation of
crop residues. Pesticides can move into organisms
like plants and insects or structures like
soil or wood, similar to the way that water
moves into a sponge. This is called - ABSORPTION.
Once inside the tissue of an organism, the
organism may use the pesticide and break it
down so that it is no longer harmful to the
organism. This reduces the hazard of pesticide
residues remaining in food. Consider these
six properties before you use a pesticide.
The fate of pesticides in the environment
is not determined by a single property but
by a combination of properties. And, the movement
of pesticides in the environment is very complex,
through the natural processes of drift, surface
runoff, leaching and soil erosion. Go to the
pesticide label for information on application
procedures for each pesticide you use to reduce
the movement of pesticides in the environment.
Mix your pesticides away from your source
of drinking water, such as your well, so that
you don’t contaminate it. Wear proper safety
equipment and protective clothing when you
mix, handle or use pesticides. Store pesticide
properly so they do not contaminate you, your
family or the environment. Before a pesticide
is registered by Health Canada to allow for
sale in Canada, the pesticide label directions
and precautions must be approved to ensure
the pesticide can be applied with minimal
risk if used according to the label directions.
Completely read the product label to check
for the environmental precautions you need
to know and follow as a user to protect your
farm, the environment around your community
and the planet. Strive to reduce the environmental
risk of pesticide use by being a responsible
user.
