For many years, the Danish Environmental Protection Agency has been working on the development and use of computer models known as (Q)SARs (Quantitative Structure-Activity Relationships). These models are used to predict the properties of chemical substances.

What are (Q)SARs?
A (Q)SAR model can estimate the relationship between the structure of chemical substances and another property, e.g. the substance's ability to cause toxic effects. (Q)SAR models can therefore be used to predict the properties of substances that are harmful to the environment or health.

Use of (Q)SAR for regulatory purposes
Authorities can use (Q)SAR models to obtain information on chemicals that have not been tested in animals or with insufficient testing data. This can be used to identify chemical substances that are under suspicion of being dangerous to man or the environment. (Q)SAR models are therefore important tools in the authorities work to ensure a high level of protection.

The work of the Danish Environmental Protection Agency relating to (Q)SAR
(Q)SAR models are used as a working tool in assessments of chemicals. In addition the Danish EPA is also involved in development of new QSAR models. The Danish (Q)SAR Database and the Advisory Self Classification List are two examples of freely available tools developed with support from the Danish EPA.

Links to various (Q)SAR tools
Many (Q)SAR tools and databases are freely available on the internet. The following text presents a brief description and links to some of the systems that are most frequently used in connection with the work relating to regulation of chemicals.