A Review of Exposure and Toxicity. The Need for Gloves and Respirators A Brief Review of Exposure.

A Review A Review of of

Exposure and ToxicityExposure and Toxicity

The Need for Gloves and RespiratorsThe Need for Gloves and Respirators

A Brief Review of ExposureA Brief Review of Exposure

Pesticide Health HazardPesticide 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

ExposureExposure

How Pesticides Enter the Body

4 Routes of 4 Routes of ExposureExposure

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

EyesEyes

NoseNose

MouthMouth

SkinSkin

Dermal Dermal ExposureExposure 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 Dermal ExposureExposure Parts of the body absorb pesticides at different ratesParts of the body absorb pesticides at different rates

Area Rate *

forehead 4.2forearm 1.0abdomen 2.1 palm 1.3 scrotum 11.8ball of foot 1.8

*Absorption rate compared to forearm (1.0)

Dermal Dermal ExposureExposure 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 Inhalation ExposureExposure

Typically occurs when using fine dusts and mists

Mixing and loading concentrates

Lung exposure is the fastest way to the bloodstream

Oral Oral ExposureExposure

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 Oral Route of ExposureExposure

Splashing during mixing or cleaning

Siphoning with the mouth

Eating Drinking Smoking Licking lips

Eye Eye ExposureExposure

Absorption through the eyes can be significant

Serious eye exposure can result from splash, spill, drift, or rubbing eyes with contaminated hands or clothing

PesticidePesticide ExposureExposure

Avoiding exposure is the key to safe pesticide use

Proper protective equipment worn correctly helps avoid exposure

The Need for Gloves and RespiratorsThe Need for Gloves and Respirators

A Brief Review of ToxicityA Brief Review of Toxicity

Hazard = Hazard = ToxicityToxicity x x ExposureExposure

Toxicity

Types of Types of ToxicityToxicity

Acute and

Chronic

Acute Acute ToxicityToxicity

single, short term exposure

the effects of acute pesticide poisoning usually occur within minutes or hours after exposure

Acute Acute ToxicityToxicity - Symptoms - 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 Acute ToxicityToxicity

Acute toxicity is expressed as:

Lethal Concentration 50 (LC50)

Lethal Dose 50 (LD50)

Lethal Concentration (LC50)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 (LDLethal Dose (LD5050)) 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 50Lethal Dose 50

The less you need to cause a toxic effect – the more toxic the substance is

Thus an LD50 of 25 mg/kg is more toxic than is an LD50 of 6,000 mg/kg

Lethal Dose (LDLethal Dose (LD5050))

higher toxicity higher toxicity ==

HIGHERHIGHER LD50LD50 = =

lower toxicitylower toxicity LOWERLOWER LD50LD50

Chronic ToxicityChronic 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:Chronic Toxicity:

(repeated exposures)

x

Threshold concentrat ion

SYMPTOMS

TIME: Weeks, months, years

Blo

od

or

Tis

su

e

Co

nc

en

trat

ion

x

x

x

x

x

x

x

Chronic Toxicity Can CauseChronic Toxicity Can Cause

Cancer Tumors Birth defects Impotence Infertility or sterility

Blood Disorders Brain damage Paralysis Emphysema, asthma Kidney problems

REMEMBER:REMEMBER:

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

Toxicity - 4 CategoriesToxicity - 4 Categories

Toxicity

Category

Signal

Word

Oral

LD50

(mg/kg)

Approx. Adult

Lethal Dose

(oral)

I

Highly Toxic Danger

Poison0-50

Few drops

to a teaspoon

II

Moderately Toxic

Warning 51-500

1 teaspoon

to

1 ounce

III

Slightly ToxicCaution 501-5,000 1 ounce to 1 pint

IV

Relatively nontoxic

Caution > 5,0001 pint

or more

Signal WordsSignal 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 / PoisonDanger / Poison

The oral LD50 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

DangerDanger

Tells nothing about the toxicity of the pesticide

Indicates that the product has a high potential to irritate or damage the eyes and skin

WarningWarning

The oral LD50 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”

CautionCaution All pesticides with an LD50 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?Where do I find LD50 values?

On the label? NO

On the product’s

MSDS

Relative Toxicity Relative Toxicity Are all substances toxic?

YES!All are toxic to some quantifiable degree

Sugar has an LD50 of 30,000 mg/kg~ 4.5 pounds

Even water has a recognized LD50 of slightly greater than 80,000 mg/kg~ 1.5 gallons

SummarySummaryYou cannot control the toxicity of a

pesticide …BUT…You can control your exposure to a

pesticide

SummarySummaryToxicity is a given amount….not in

control of applicatorExposure 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 The best way to avoid a pesticide poisoning is to protect pesticide poisoning is to protect

yourself by yourself by

Reading the labelReading the label andand

Wearing personal Wearing personal protective equipmentprotective equipment

SummarySummary

This presentation produced through a grant in cooperation withThis presentation produced through a grant in cooperation withThe Pennsylvania State University Pesticide Education ProgramThe Pennsylvania State University Pesticide Education Program

by the Southwestern Pennsylvania Pesticide Educators Committeeby the Southwestern Pennsylvania Pesticide Educators Committee

www.pested.psu.eduwww.pested.psu.edu