Risk

Measuring the effects of a hazard in an area. Risk significance therefore depends on the hazard but also on exposed challenges (populations, property and the environment) and on their vulnerability. There is no risk when the area exposed to a hazard is devoid of human, material and environmental challenges.

Action to eliminate or reduce an immediate risk to an acceptable level (e.g. through removal or disposal of hazardous products and wastes from a site, by prohibiting or limiting access to the site, or by eliminating the risks of fire and explosion, etc).

Maximum tested dose causing no mortality in the studied population of organisms during a given time, with single-dose administration (LD0). The dose causing a 50% (or n%) of deaths in the studied population of organisms during a given time, with single-dose administration, is rated LD50 (or LDn).

(Internal or external) dose of substance received by the organism related to the weight of the individual and the number of exposure days (in the case of a non-carcinogenic substance) and to the number of days in a lifetime (in the case of a carcinogenic substance).

Maximum allowable concentration for a pollutant in a medium (air, water, soil) in a food or drink.

Concentration of a toxic substance that causes the death of a percentage n in a given population, for a given time and in a given experiment (LCn). We speak of LC0 for the maximum tested concentration applied in a single dose and causing no death in the population of studied organisms during a given time. Finally we talk about LC50 for a concentration applied in a single dose and causing 50% mortality in the population of…

Substances that could cause serious problems in a living organism and possibly cause death (see toxic pollution).

Risk which is characterized by both a low probability of occurrence and huge seriousness of a given event should it occurs (many casualties, extensive damage to property and the environment).