A Review of Exposure and Toxicity

The Need for Gloves and Respirators A Brief Review of Exposure

Pesticide Health Hazard Pesticide Health Hazard Pesticide health hazard is determined by the toxicity of the pesticide and the amount of exposure to the pesticide Hazard = Exposure x Toxicity

Exposure How Pesticides Enter the Body

4 Routes of Exposure Dermal - any covered or uncovered skin Eyes – direct splash or contact with hands Inhalation – carried in with air Oral – taken into mouth or on lips Eyes Nose Mouth Skin

Dermal Exposure 97% of all pesticide exposures are dermal The most common route is through the hands and forearms Dermatitis is most common reported symptom associated with exposure

Dermal Exposure Parts of the body absorb pesticides at different rates AreaRate * forehead 4.2 forearm 1.0 abdomen 2.1 palm 1.3 scrotum 11.8 ball of foot 1.8 * Absorption rate compared to forearm (1.0)

Dermal Exposure Formulations vary in their ability to be absorbed through the skin. Emulsifiable concentrates are more readily absorbed than other formulations All formulations can be absorbed in clothing, thereby becoming a path to skin exposure

Inhalation Exposure Typically occurs when using fine dusts and mists Mixing and loading concentrates Lung exposure is the fastest way to the bloodstream

Oral Exposure Poisoning occurs most often when pesticides have been taken from original container and put in unlabeled bottle or food container Children are most common victims

Oral Route of Exposure Splashing during mixing or cleaning Siphoning with the mouth Eating Drinking Smoking Licking lips

Eye Exposure Absorption through the eyes can be significant Serious eye exposure can result from splash, spill, drift, or rubbing eyes with contaminated hands or clothing

Pesticide Exposure Avoiding exposure is the key to safe pesticide use Proper protective equipment worn correctly helps avoid exposure

The Need for Gloves and Respirators A Brief Review of Toxicity

Hazard = Toxicity x Exposure Toxicity

Types of Toxicity Acute and Chronic

Acute Toxicity single, short term exposure the effects of acute pesticide poisoning usually occur within minutes or hours after exposure

Acute Toxicity - Symptoms Dermal - skin irritation, itching, reddening Oral - nausea, muscle twitching, sweating, weakness Inhalation - burning of throat and lungs, coughing Eye - temporary or permanent irritation or blindness

Acute Toxicity Acute toxicity is expressed as: Lethal Concentration 50 (LC 50 ) Lethal Dose 50 (LD 50 )

Lethal Concentration (LC50) The concentration of a chemical in an environment (generally air or water) which produces death in 50% of an exposed population of test animals in a specified time frame mg/L Normally expressed as milligrams of substance per liter of air or water (ppm)

Lethal Dose (LD 50 ) Subject test members to different dosages of the active ingredient and each of its formulated products Amount of a chemical that it takes to kill 50% of the test population mg/kg Expressed in milligrams of chemical per kilogram of body weight of the test animal

Lethal Dose 50 The less you need to cause a toxic effect – the more toxic the substance is Thus an LD 50 of 25 mg/kg is more toxic than is an LD 50 of 6,000 mg/kg

Lethal Dose (LD 50 ) higher toxicity = higher toxicity = HIGHER LD50 = lower toxicity lower toxicity LOWER LD50

Chronic Toxicity Potential of a pesticide to cause injury from repeated or prolonged exposure to small doses of pesticides. Delayed - time lapses between exposure and effects

Chronic Toxicity: (repeated exposures)

Chronic Toxicity Can Cause Chronic Toxicity Can Cause Cancer Tumors Birth defects Impotence Infertility or sterility Blood Disorders Brain damage Paralysis Emphysema, asthma Kidney problems

REMEMBER: Repeated low-level exposure to chemicals can increase the possibility of future adverse health effects

Toxicity - 4 Categories Toxicity Category Signal Word Oral LD50 (mg/kg) Approx. Adult Lethal Dose (oral) I Highly Toxic Danger Poison 0-50 Few drops to a teaspoon II Moderately Toxic Warning teaspoon to 1 ounce III Slightly Toxic Caution 501-5,0001 ounce to 1 pint IV Relatively nontoxic Caution > 5,000 1 pint or more

Signal Words “Warning signs” on the label that indicate the toxicity of the pesticide to both humans and animals Signal words measure acute toxicity for skin, mouth, lung and eye exposure

Danger / Poison The oral LD 50 is from a trace amount up to 50 mg/kg of body weight Label must have the signal word “DANGER/PELIGRO” plus the word “POISON” Label also must display the skull and crossbones icon Human Exposure – trace to teaspoon is fatal to 150lb. person

Danger Tells nothing about the toxicity of the pesticide Indicates that the product has a high potential to irritate or damage the eyes and skin

Warning The oral LD 50 is between 50 and 500 mg/kg of body weight Pesticides in this category are classed as “moderately toxic” Human Exposure - two teaspoons is fatal to 150lb. Person “WARNING/AVISO”

Caution All pesticides with an LD 50 of greater than 500 mg/kg must display this word on their label Actually includes two groups of pesticides – those classed by the EPA as “Relatively nontoxic (>5,000 mg/kg) and those classified as “slightly toxic” (500 – 5,000 mg/kg)

Where do I find LD50 values? On the label? NO On the product’s MSDS

Relative Toxicity Are all substances toxic? YES! All are toxic to some quantifiable degree Sugar has an LD 50 of 30,000 mg/kg ~ 4.5 pounds Even water has a recognized LD 50 of slightly greater than 80,000 mg/kg ~ 1.5 gallons

Summary Summary You cannot control the toxicity of a pesticide …BUT… You can control your exposure to a pesticide

Summary Toxicity is a given amount….not in control of applicator Exposure is determined by applicator …therefore, if exposure is low or zero (0) then health hazard is also low or zero Using the equation: Toxicity x Exposure = Hazard 90 x 100 % (1.0) = 90% 90 x 0.0 % (0.0) = 0%

The best way to avoid a pesticide poisoning is to protect yourself by Reading the label Reading the labeland Wearing personal protective equipment Summary

This presentation produced through a grant in cooperation with The Pennsylvania State University Pesticide Education Program by the Southwestern Pennsylvania Pesticide Educators Committee