Types of Exposure

Maggie Scarbrough

If a person has contact with pesticides they may be harmed either by poisoning or injury. Internal physical damage is poisoning while external physical damage would be considered an injury.


The severity of effects of pesticides will depend on the amount of overexposure. Pesticides that have a similar chemical makeup will have similar effects. Some may cause internal poisoning and external injury. A particular chemical group may have the same pattern of illness or injury.


There are a few pesticides that are considered highly toxic. These chemicals may cause severe damage with only a few drops. The risk of harmful effects from pesticides is the hazard. To assess the amount of damage that can be caused, remember: HAZARD=Toxicity x Exposure. The hazard associated with a pesticide is directly dependent on the toxicity of it and the amount of exposure to it.


Pesticide exposure is when a pesticide contacts a surface or a living organism. The toxic effect depends on the amount of pesticide present and the length of exposure. For a person, exposure means you have gotten pesticide on or in your body.


Exposure occurs in one of four ways: oral (consumed), inhalation (inhaled), ocular (in your eyes), and dermal (on your skin).


To reduce harmful effects of pesticide exposure, there are certain safety precautions that can be taken. Wearing protective equipment, washing exposed equipment, and using closed systems are just some ways to reduce exposure.


Ninety-seven percent of all body exposure is dermal. Inhalation exposure becomes a bigger threat if work must be conducted in a poorly ventilated area.


Several factors determine the amount of pesticide absorption. The pesticide and its diluent are important. Dry formulations are not easily absorbed while water-based are more readily absorbed. The most likely concentrates to be absorbed through the skin, however, are emulsifiable concentrates and oil-based liquid pesticides. Another factor is the area of the body exposed. Highly absorptive areas include the scalp, ear canal, and forehead. The genital area is considered the most absorptive. Skin condition is also a factor. Hot, sweaty skin is more absorptive than cool, dry skin and areas that have cuts, rashes or abrasions more easily absorb chemicals.


To better avoid exposure, it is necessary to learn most common means of exposure. Oral exposure often results when hands are not washed prior to eating, drinking, smoking or chewing. Pesticides have also been mistaken for food or drink or applied to food or drink. Carelessness is most always the underlying factor.


Poorly ventilated areas, toxic fumigants, and lack of proper protective gear are usually the culprits when it comes to inhalation exposure. Using respirators that do not fit properly or reentering sprayed areas too soon are also risk factors for inhalation.


Dermal exposure often occurs by not washing properly, splashing or spraying pesticides, wearing contaminated clothing, wearing inadequate equipment, touching treated areas and by applying in windy weather.


Some similar factors contribute to eye exposure, like splashing and spraying pesticides as well as use in windy weather. Improper eye protection during handling of dust and powder formulations is also risky. Contaminated gloves or hands are also often inadvertently rubbed on eyes or forehead.