Routes of Exposure

The ways that pesticides enter the body are referred to as the routes of exposure. While it is a rather simplistic approach, we can refer to these routes as dermal (through the skin), respiratory (through the lungs and respiratory system) and oral (through the mouth including adsorption through the gastrointestinal tract). Routes of exposure have been discussed by many authors including: Bohmont (1983) and Ottoboni (1984). Based on the work of Gold et al. (1982) and Leavitt et al. (1982) dermal exposure is of major concern for urban pest control operators. Ottoboni (1984) indicates that intact skin presents a significant barrier to the penetration of pesticides into the body. She states that the majority of inorganic chemicals are not absorbed through intact skin, but that organic chemicals may or may not be absorbed. Organic chemicals in dry powder form are absorbed to a lesser degree than the same chemical in a solution, suspension or paste.

Oily solutions permit greater absorption than water solutions. Areas of the body also differ in chemical absorption.

Inhaled chemicals present an important route of entry into the body as the lungs have a tremendous surface area and many chemicals can pass easily through the lung tissues into the blood stream (Ottoboni, 1984). The importance of respiratory exposure also was recognized by Durham and Wolfe (1962) who advocated that this route of exposure is 10 times more important than dermal in terms of potential for penetration. This discussion obviously leads to the point that respiratory protection is needed when working with pesticides that are easily inhaled.

Oral exposure to pesticides can take various forms, but generally is associated with chemicals on/or in food or drink. Oral exposure can be a problem with children who have access to pesticides in home environments. It is unfortunate, but the majority of fatal exposure incidents involve children under the age of five, who ingest over-the-counter pesticide products (products with relatively low concentrations of toxic ingredients). For professional pesticide applicators it is important to recognize the importance of oral exposure to chemicals in terms of preventing access to stored chemicals by unauthorized persons, and to make sure that pesticide applicators refrain from using pesticides when eating, drinking or smoking.

Care must also be taken in applying pesticides in food handling and storage areas to avoid contaminating food stuffs.