Biocides can only be authorised for use in Denmark if they do not pose an unacceptable risk to health. But how does the Danish Environmental Protection Agency assess the effects on health?
The Danish Environmental Protection Agency looks partly at studies of the active substance, which is the effective element against the harmful organism and partly at the product, which is a mixture of the active substance and one or more other sub-stances. The majority of studies submitted are carried out on the active substance.
Evaluation of the active substance
Based on the studies of tests animals and other information submitted by the applicant, we look at how acutely toxic the substances are and what effects they have both in the medium term and in the long term.
The acute studies investigate how dangerous the substance would be if a person were to be exposed to it on a single occasion. This gives an indication of how dangerous it would be if a person were to accidentally eat or drink the substances, or how dan-gerous it would be to pour it over the skin or to inhale it. Whether the substances irritate the eyes or the skin and whether they are allergenic is also investigated.
An investigation is then carried out to determine any harmful effects that the substances may have on health in the medium and the long term. The investigation could for example examine whether the substance has carcinogenic properties, or whether it adversely affects reproductive ability or the unborn child or whether it affects the genome, but also whether the substance harms various organs, e.g. the nervous system, heart, liver, etc.
The tests designed to provide such information use several different doses and a NOAEL (No Observed Adverse Effect Level) value is determined, which is the highest dose at which no harmful effects can be seen.
Evaluation of the product
For many products, studies are often only available for acute effects, for potential eye and skin irritation and whether they cause allergic reactions.
A person who uses a wood preservative or insect repellent, for example, will get some of the substance on them, and some of this will enter the body. How much enters the body can be calculated using different models for the substance concerned (exposure calculation).
The amount that enters the body is compared with the highest dose that did not produce a harmful effect in the tests on animals. In order to take account of differences between people and animals and between different people, a safety factor is used. This is usually 100, but may be different in some cases depending on, for example, the severity of the effects and the quality of the data.
Under the current national Danish rules, these exposure calculations are carried out in only a few cases depending on the properties and use of the substance. When a substance is to be evaluated under the EU rules, exposure calculations must be performed for everyone who could come into contact with the substances (except those involved in the manufacture of the sub-stance).
Until a substance has been included in Annex I to the Biocidal Products Directive (also known as "the positive list"), the evaluation is carried out in accordance with the Danish national rules.
When a substance is included in Annex I to the Biocidal Products Directive, the evaluation is carried out in accordance with several guidelines which can be found on the European Commission's website