Welcome to the Grower Pesticide Safety
Course. This presentation is on Chapter 8 Health Risks of Pesticide Use. Chapter 8
starts on page 95 of the manual. There are twelve slides in this presentation
and it’ll take us about ten minutes to review. Let’s get started. What will I
learn? By the end of this lesson you should be ready to, define risk, toxicity
exposure, identify and describe routes of exposure, compare acute and chronic
toxicity, describe the health risks of pesticide use, and list ways to prevent
pesticide exposure. Each time that you handle a pesticide you are at risk. Just
as you would be with household cleaners, medications, you can harm yourself if you
don’t handle them properly. The amount of risk depends on two things — the toxicity
of the pesticide and your exposure to it. So toxicity is a measure of how harmful
or poisonous a pesticide is. Exposure is a measure of the contact you have with
the pesticide. Now you can control your exposure. You may have to deal with the
toxicity of the product – the one that you’ve chosen to use. But you can always
reduce your exposure, and if your exposure is zero, any number times
another number, that’s zero. Your risk will be zero. So protect yourself from
exposure to lower your risk. To do that, follow the label directions. Wear the
protective clothing and the personal protective equipment that’s stated on
the label for that product. Now how do we measure our toxicity. Toxicity is the
measure of how harmful the pesticide is or poisonous it is. And before a
pesticide product is approved by the Pest Management Regulatory Agency of
Health Canada, it’s tested to determine how dangerous
it is for a single dose exposure and also repeated exposures. So the acute
toxicity is the toxic response that results from the single exposure or
exposure over a short period of time, and we’re talking 24 hours, 48 hours, short
period of time, a single exposure . Chronic toxicity, chronic, long-term, it’s the toxic
response that results from repeated exposures over a longer time. And so PMRA, Health Canada will review studies for both the acute toxicity and the
chronic toxicity. Acute toxicity is measured by Lethal Dose 50 percent, LD50. Now we’ve
talked briefly in other chapters about an LD50, the dose of the pesticide that
kills 50 percent of the test animals. On a pesticide label, we’ve mentioned in
Chapter 3, The Pesticide Label, that there are symbols that will appear on the
front panel, principal display panel of the product label, and that’s determined
based on the criteria of acute oral LD50, acute dermal LD50, or the acute
inhalation LC50 for the product and how that’s been
determined. The lower the LD50 value, the more toxic the pesticide. That means the
smaller amount you would have to take in your body or be exposed to, to have a
toxic effect. So that is a more toxic product. Here is a chart in your manual
with some of the pesticides and the corresponding symbol that will be on the
front, and how that relates back to the acute oral, the acute dermal, and the acute
inhalation LC50. Dermal means skin, acute oral would be through the mouth or
product taken in through ingestion, and acute inhalation is taking in through the
nose and the lungs in a respiratory way. The LD50
is less than 10 milligrams per kilogram — you know that pesticide is extremely toxic. And this can be the case with some of the rat poisons. If there’s
no symbol on a pesticide label, then you would realize that none of the criteria
has been met and it is not as toxic. Chronic toxicity — acute toxicity doesn’t
tell you the full story. You need more information about what would happen over
the long term, and that is chronic toxicity. Sorry. To protect you from
chronic poisoning, the label will have precautionary statements you must follow. For example, a pesticide product may limit the number of hours you can use
the product in one day, and if that’s on the label that statement would be a
result of chronic toxicity evaluation by the Pest Management Regulatory Agency. Scientists conduct studies to find out if the product could cause cancer, tumor
growth or birth defects. Let’s talk a little bit about sensitization and
allergies. Some people are more sensitive to certain pesticides than others. You
may have an allergy to an active ingredient or another chemical used in
the formulation. Allergens are stated on the front of the label on that principal
display panel. So peanuts, sulphites, milk eggs, shellfish, soy, wheat, sesame seeds,
those could all be part of the formulation of a pesticide. So if there
is an allergen, there’ll be a warning — “contains the allergen ____” and it will state
sulphites or egg or whatever — it’ll name it. Some people are more sensitive to
certain pesticides than others. A person may not react the first time but may
react the next time he or she uses the product. So look for warnings on the
front of the label: Danger Skin Irritant, Potential Skin Sensitizers. Those are the
clues on very front on the label. You should be
careful for skin exposures. The U.S. Agricultural Health Study. In 1993
scientists in the United States began the study known as the Agricultural
Health Study and the study has nearly 90,000 participants from Iowa and North
Carolina who are farmers or farm family members. So some results of the
Agricultural Health Study have been published and again you can go to the
website and look at the published information there. Certain pesticides are
linked to higher risk of developing non-hodgkins lymphoma, Parkinson’s,
diabetes, and thyroid disease. We worry about protecting others when we’re using
pesticides not only our exposure but exposure to others. So keep pesticides out
of reach of children. Pregnant or breastfeeding women should
not contact pesticides. Keep people, pets and livestock from exposure. I was
talking to a pesticide applicator and he was applying pesticides to his field and
the pet dog was running behind the sprayer. Things like that can be avoided.
Make sure that people, pets and livestock are not going to be exposed. Follow the
Restricted Entry Intervals. Follow the pre-harvest intervals on the label. And
finally prevent take-home exposure. Family members and pets could be exposed
if a person who used a pesticide then contaminates the home or vehicles. So you
want to take off your protective clothing and equipment before you get into a
truck or a car. Don’t touch the door handles, steering wheels, or cell phones.
If you’ve got contaminated pesticide gloves. take the gloves off first,
and remove your protective clothing and equipment before you get into your car,
truck or tractor cab. There’s a brief overview of the health risks of using
pesticides. You can review that further in your chapter.