IUPAC Glossary of Terms Used in Toxicology - Terms Starting with W

waste
Anything that is discarded deliberately or otherwise disposed of on the assumption that it is of no further use to the primary user.

wasting syndrome
Disease marked by weight loss and atrophy of muscular and other connective tissues that is not directly related to a decrease in food and water consumption.

water potential (in physiology)
Difference in free energy or chemical potential (per unit molal volume) between pure water and water in cells and solutions.

Weibull model
Dose-response model of the form

where P(d) is the probability of a tumor (or other response) from lifetime, continuous exposure at dose d until age t (when tumor is fatal), α is a fitted dose parameter (sometimes called the Weibull parameter), Β is a fitted dose parameter, and γ is the background response rate.

weight-of-evidence for toxicity
Extent to which the available biomedical data support the hypothesis that a substance causes a defined toxic effect such as cancer in humans.

withdrawal effect
Adverse event following withdrawal from a person or animal of a drug to which they have been chronically exposed or on which they have become dependent.

working zone
Space measuring up to 2 m over the level of the floor or platform that contains a worker's permanent or temporary station.