Risk Assessment and Management in Toxicology

Risk

Probability of an adverse effect in an organism, system or population caused under specified circumstances by exposure to an agent. Probability of harm from a substance. Hazard x exposure

Hazard

Inherent capability of a substance to cause harm such ass illness, injury or death

Exposure

likelihood or amount of contact

Risk Assessment

Process to calculate or estimate the risk of a given target organism, system or population after exposure to a particular agent taking into account the characteristics of the agent and the characteristics of the target system.

Hazard Identification

Identifying whether exposure to a substance can cause harmful effects. Are they persistent, bioaccumulative, toxic. Worked out using human observations, studies of animals and studies of cells, presumptions based on chemical structure, relationship between exposure and disease and pre-exisitng databases.

Dose-Response Assessment

Quantifying the relationship between the magnitude of exposure (dose) to a substance and the severity and probability of the adverse effect.

Exposure Assessment

How much people are exposed to the substance. The source (concentration etc), type (inhalation, ingestion, dermal), magnitude and duration of the exposure.

NOAEL

No observed adverse effect level - Highest exposure at which no adverse effect is seen

LOAEL

Lowest observed adverse effect level - lowest exposure at which adverse effect is seen

Factors affecting toxicity

dose

duration

route of exposure

species

age

sex

genetics

lifestyle factors

Risk Characterisation

estimate the likelihood and severity of adverse health effects based on hazard, dose and exposure

Uncertainties: Data gaps, extrapolating from animals to humans, variations in individuals.

Exposure Pathway

The route through which a person may be exposed to a hazardous substance. inhalation, ingestion, dermal

In Vivo Testing

Testing conducted on living organisms.

In Vitro Testing

Testing conducted outside of a living organism, typically in a lab setting.

Risk management

Actions to reduce identified risks

• exposure limits

• safety measures

• restricting/barring cehmicals

• public health policies

These actions are influenced by

• evidence of risk

• cost of implementing

• social and political considerations

• feasibility

• public perception

Risk communication

Exchange of information about risks between experts, officials and the public. It is two way communication: experts giving information and listening to concerns and perceptions.