Precautions with Pesticides: Human Health

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Table of Contents

1. Risks of Pesticide Use
   • Table 1-2 Acute Toxicity Levels of Certain Pesticides
2. Exposure
3. Cholinesterase Blood Tests
• Table 1-3 Organophosphorus and Carbamate Pesticides
4. First Aid
5. Other topics on Precautions with Pesticides
   • Pesticide Regulations
   • Certification and Training Requirements
   • General Precautions
   • Read and Follow Pesticide Label Information
   • Human Health
   • Protective Clothing and Equipment
   • Protect the Environment
   • Disposal of Pesticides and Empty Pesticide Containers
   • Storing Pesticides
   • Pesticide Spills
   • Application Procedures
   • Precautions with Pesticide Tables
     • Pesticide Schedules in Ontario (Pesticide Regulations)
     • Safety Supply Companies in Ontario Providing Protective Clothing & Equipment (Table 1-1)
     • Pesticides Act Storage Requirements (Table 1-2)
6. Related Links

Risks of Pesticide Use

Each time you handle a pesticide, you are at some risk. The amount of risk depends on two things – the toxicity of that pesticide and your exposure to it.

Toxicity is a measure of how harmful or poisonous the pesticide is. There are 2 types of toxicity:

• Acute toxicity - the toxic response that results from a single exposure to the pesticide. The symbols and words on the front panel of a pesticide label give you information about the acute toxicity.
  • Lethal Dose 50% (LD50) is a measure of Acute Toxicity. It is the dose (mg of product per kg of body weight) that will kill 50% of the test animals within a stated period of time (24 hr. – 7 days). Products with low LD50 ratings are highly toxic.
• Chronic toxicity - the toxic response that results from repeated exposures to small doses of a pesticide over a longer period of time. These toxic effects may not appear for months or years after exposure to the pesticide. The symbols on the label do NOT give information about the chronic toxicity of the product. Use protective clothing and equipment to help reduce exposure and the risk of chronic effects.

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Exposure

Exposure is a measure of the contact workers have with the pesticide, which can occur in three ways.

• Dermal exposure occurs through the skin or eyes. The amount and rate of pesticide that may be absorbed depends on several things, including:
  • skin condition. If skin is moist, or has rashes, broken skin or scratches, the pesticide will be absorbed more easily
  • the part of the body exposed. Eyes, genital area, scalp and ear canals absorb pesticides at a higher rate than do hands or arms. Eyes absorb pesticides at a rate of 100%.
• Respiratory exposure (inhalation) occurs when small spray particles, dust, gases or vapours are inhaled.
• Oral exposure occurs when a pesticide enters the mouth or when you swallow a pesticide.

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Cholinesterase Blood Tests

Organophosphorus and carbamate pesticides can affect your nervous system. These pesticides can change your serum and red blood cell levels of an enzyme called acetyl cholinesterase. The body uses this enzyme to transmit messages through the nervous system. If your cholinesterase levels fall, you can experience symptoms including trembling, twitching, blurred vision, difficulty breathing and heart difficulties.

If you use any of the groups of pesticides listed in Table 1-3, Organophosphorus and Carbamate Pesticides, above, on a regular basis, have regular cholinesterase blood tests. Your family doctor can arrange these tests, which are covered by OHIP.

Have your first test during the off-season, before you begin to handle these pesticides. That will show the baseline (normal) cholinesterase level for your body. During the spray season, if you are spraying organophosphorus or carbamate insecticides regularly for several weeks, have a cholinesterase blood test every 7-10 days.

If your cholinesterase level drops to below one-half of your baseline level, then you are showing signs of pesticide poisoning and you must remove yourself from exposure to these pesticides until your cholinesterase level returns to normal.

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First Aid

1. Always protect yourself from injury first. Don't become another victim. Always put on protective clothing and equipment before you enter a contaminated area or handle a contaminated victim.
   
2. Check to see if the victim is breathing.

   If the victim is not breathing:

   • Straighten the victim's airway and check for breaths.
   • If the victim does not begin to breathe, administer artificial respiration until the victim begins to breathe on his/her own.
   • Do not contaminate yourself, especially if the victim has pesticide or vomit around his face or mouth. Use a face shield airway with a one way valve. Do not breathe the exhaled air from the victim.
   • Perform CPR if the victim's pulse disappears. You should only perform CPR if you are trained to do so.

   If the victim is breathing, but unconscious:

   • Place the victim in the recovery position (on the side with the head turned slightly to one side). If the victim vomits, try to keep the airway clear.
     
3. Stop the exposure to the pesticide. Move the victim away from the contaminated area. Remove all contaminated clothing. Use soap and water to wash any skin exposed to the pesticide.
   
4. Check the Four Basic Facts:

   Identify the pesticide. Look for the label, container or leftover pesticide.

   Quantity. How much product was the victim exposed to?

   Route of entry. How did the pesticide enter the body? Did it enter through the mouth, skin/eyes or lungs?

   Time period. How much time has passed since the victim was exposed to the pesticide, and how long was the exposure? Were the symptoms immediate or did the poisoning occur as a result of using the pesticide over a longer period of time?

Don't waste time. If you can't answer these questions quickly,
be ready to tell emergency personnel whatever you can.

5. Call an ambulance or the Poison Information Centre.
   
6. Start the First Aid treatment appropriate for the route of entry.
   
7. Make sure the patient gets medical attention. First aid is not a substitute for professional medical help.
   
   If symptoms of illness occur during or shortly after handling a pesticide, go to a hospital.
   Take the pesticide label, MSDS sheet, or pesticide container with you.
   Do not transport the container in the passenger compartment of the vehicle.
   Refer to the Emergency Procedures for Pesticide Poisoning.

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Related Links

• Publication 75, Guide to Weed Control
• Publication 812, Field Crop Protection Guide
• PMRA website

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