I. INTRODUCTION – RISK MANAGEMENT

The technique of risk assessment is used in a wide range of professions and academic subjects. Engineers "risk assess" bridges to determine the likelihood and effect of failure of components, and social welfare workers "risk assess" their clients to determine the likelihood of the reoccurrence of anti-social behavior. Risk assessment has become a commonly used approach in examining environmental problems. It is used to examine risks of very different natures. Definitions in risk assessment are all-important because of the wide range of uses of the approach, and different meanings of terms used by different groups of experts and practitioners.
Hazard is commonly defined as "the potential to cause harm". A hazard can be defined as "a property or situation that in particular circumstances could lead to harm" Risk is a more difficult concept to define. The term risk is used in everyday language to mean "chance of disaster". When used in the process of risk assessment it has specific definitions, the most commonly accepted being "The combination of the probability, or frequency, of occurrence of a defined hazard and the magnitude of the consequences of the occurrence".
The distinction between hazard and risk can be made clearer by the use of a simple example. A large number of chemicals have hazardous properties. Acids may be corrosive or irritant to human beings for example. The same acid is only a risk to human health if humans are exposed to it. The degree of harm caused by the exposure will depend on the specific exposure scenario. If a human only comes into contact with the acid after it has been heavily diluted, the risk of harm will be minimal but the hazardous property of the chemical will remain unchanged.
There has been a gradual move in environmental policy and regulation from hazard-based to risk-based approaches. This