Exposure Analysis

Determining toxicity and exposure is necessary in a chemical risk assessment. Exposure to a chemical can occur through direct or indirect routes. Direct exposure is easier to identify, for example, exposure to nicotine and carbon monoxide from smoking cigarettes, or exposure to a pesticide from swimming in a contaminated lake. Indirect exposure can be somewhat more elusive, for example, mercury exposure by eating fish from mercury-contaminated waters. Whether direct or indirect, human exposure to chemicals will be dermal (skin contact), oral (contact by ingestion), and/or inhaled (contact by breathing).

Assessing human exposure to a chemical involves first determining the magnitude, duration, frequency, and route of exposure; and second, estimating the size and nature of the exposed population. Questions include to what concentration of chemical is a person exposed? How often does exposure occur—is it long-term or short-term, continuous or varied? What is the route of exposure—is the chemical in foods, consumer products, or in the workplace? Is the chemical bioactive, or is it purged from the human system without causing any harmful effects? Are special risk groups, such as pregnant women, children, or the elderly, exposed?

0 0

Post a comment