Introduction

Classes and uses of pesticides

Legal framework

Approval Levels

Scientific information in the regulatory process.

Risk Management Process

Constitution and function of the various organisations

Management of pesticides in the future.

Potential toxicity in humans....

Data on potential toxicity are required for the active substance, the product as a whole, and also any important metabolites of the active substance to which humans might be exposed. These data are derived largely from tests in laboratory animals, but care is taken to ensure that all use of laboratory animals is the minimum strictly necessary. If reliable information can be obtained by other means, these are used in preference. When products are first considered for provisional approval, any human exposure to them has usually been rather limited. However, where information on the health of exposed humans is available (e.g. of workers involved in their manufacture and testing), this is taken into account.

An important objective of the toxicological assessment is to establish “No adverse effect levels” (NOAELs) for any ill-effects that might occur. A NOAEL is the highest dose in an investigation that does not cause ill-effects.

The data that are required to assess potential human toxicity cover:

• How the active substance is metabolised and excreted in mammals.

• The "acute" toxicity of a single high dose of the active substance and of the product by oral, dermal and inhalation exposure, usually in rats

• The "sub-acute" and "chronic" toxicity of the active substance when administered to animals over periods of several weeks or longer (in two species, typically rats for up to two years and dogs for up to a year).

• The potential of the active substance to cause cancer when it is administered over a lifetime (in two species, usually in rats for a minimum of two years and in mice for 18 months).

• The genotoxicity of the active substance – i.e. its potential to damage the genetic material in cells.

• The developmental toxicity of the active substance – i.e. whether it can cause fetal death or malformations when administered to female animals during pregnancy.

• The toxicity of the active substance when it is administered to at least two successive generations of animals over the course of their lifetime. As well as providing further information on the chronic toxicity of the pesticide, this addresses its potential to impair fertility and the ability to rear young.

• The potential of the active substance and product to irritate the skin or eyes.

• The potential of the active substance and product to cause allergies (sensitisation).

• Further tests may be required if there is a need to understand effects better, for example on particular organ systems such as the nervous, immune, or endocrine systems.

On the basis of these data, a decision is made as to whether the product requires labelling as a hazard (eg. irritant, harmful, toxic). In addition, acceptable levels of exposure or reference doses may be defined.