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Hazard, risk, human health and pesticides


Please note these defintions relate to the issues discussed in this section on pesticides and human health

Absorption: the process of a substance entering the body.

Absorption rate: how fast a substance is absorbed relative to another substance in the same situation.

AOEL: Acceptable Operator Exposure Level, ie the exposure level for a particular pesticide use that has been been shown to be safe in various studies.

Cellular repair: the ability of cells to repair damage which occurs from toxic substances.

Distribution: the transfer of a substance within the body.

Dose: the quantity of a substance administered or taken in to the body. Can be given by various routes eg through the mouth (oral) or via the skin (dermal).

Dose response curve: a graph showing how observable effects change relative to increasing dose, for a specific substance administered in a specific test.  

Dose response evaluation: the determination of the quantitative relationships between internal dose and effects observed.

Excretion: the elimination of waste products from the body. In mammals types of excretion are via the kidneys in urine; via the lungs in air (carbon dioxide); biliary excretion which is via the bile and ultimately the faeces; mucociliary excretion which is via the mucous from the respiratory tract (ie, blowing the nose); and perspiration via the skin.

Exposure: coming into contact with a substance.

Exposure mitigation: processes or controls to minimise the chance of exposure or the effect of exposure.

Exposure modelling: a way of assessing potential human exposure using a computer model containing a data set of relevant parameters for different real-life scenarios.

Hazard: a situation that under certain circumstances has the potential to do harm. Potential harm may be a threat to life, health, property or the environment. Most hazards are dormant or potential, with only a theoretical risk to do harm. However an active hazard can create a serious or emergency situation. There are many ways of classifying hazards, but in respect to pesticides, physical hazards and health hazards are particularly relevant.

Hazard profile: a list or review of all the known hazards of a substance or situation.

Hazardous substance: a substance which has the potential to cause harm to people or the environment.

Human exposure assessment: determining how people might be exposed to a substance under specific circumstances. Takes into account the source, route, magnitude and frequency of exposure.

LD50: the amount of a substance that causes one half of the animals in a specific test to die. A measure of the lethal dose to 50% of the organisms treated.

Metabolism: a set of chemical reactions that occur in living organisms in order to maintain life, including both breaking down food to provide nutrients and breaking down poisons or toxins to remove them from the body.

Mg/kg bw: is the abbreviation for milligram per kilogram bodyweight, and means the quantity of the dose administered in milligrams, divided by the weight of the individual or animal in kilograms. This allows for direct comparison of results of different tests which involve animals or people of different body sizes and weights.

NOAEL: No Observed Adverse Effect Level: in a toxicological study, the dose level below which no undesired toxic effects are seen or measured. The observed effects are compared statistically to those of non-treated controls in the same test.

NOEL: No Observed Effect Level: in a toxicological study, the dose level below which no effects at all are seen or measured, compared statistically to non-treated controls in the same test.

Physical and chemical properties: measurable aspects of a substance or thing.

Physical properties: properties that do not change the chemical nature of matter. Examples are boiling point, melting point, colour, smell, density, opacity, viscosity, magnetic attraction or repulsion, physical state (solid, liquid or gas).

Chemical properties: properties that do change the chemical nature of matter. Examples are pH, electromotive force, heat of combustion, reactivity with other substances.

Physical hazard: a hazard that results from a physical property. For example flammability and explosivity.

Pictograms: diagrams included on labels to show hazards of a pesticide without the use of words. The FAO has published a set of standard pictograms which are used in many countries.  (downloads Word document).

Reference dose: the maximum acceptable oral dose of a toxic substance (USEPA).

Risk: the probability that a particular adverse event will occur during a stated period of time under specified conditions.

Risk management: following risk identification and assessment, risk management is the coordinated and economical application of resources or processes to minimise, monitor or control the probability and/or impact of unwanted events.

Safety: the probability that harm will not occur under specified conditions (i.e. the opposite of risk).  

Safety margin: a number, factor or allowance to ensure safety. For pesticides it is an additional margin between the NOAEL and the measured exposure level for a particular use situation and a particular pesticide. A common safety margin is 100.

Surveillance: in relation to pesticide use, ongoing observation or monitoring of people potentially exposed to pesticides to determine real level of exposure.

Susceptibility: how sensitive an individual is to a particular hazard situation compared to other individuals. How much an individual would suffer if exposed to a particular substance, compared to others.

Toxicology: The study of adverse effects of substances on living organisms.

VMD: “Volume Mean Diameter”a measure of droplet size distribution in a spray, where one half of the spray volume consists of larger droplets and one half of smaller droplets.

Hazard, risk, human health and pesticides | Basic principles of toxicology | Assessing the risk to human health | Glossary - human health section