For substances that do not have a drinking water quality criterion, it is necessary to carry out a toxicological assessment to arrive at the acceptable concentration in the drinking water.
The toxicological assessment is based on the inherent properties of the chemical substance. On this basis, an acceptable level is set for the concentration in the drinking water (acceptance requirement).
The assessment is based on the substance's TDI (tolerable daily intake) - if this exists - and follows the principle for determining the health-based quality criterion for drinking water.
For those substances where there is no TDI either in Denmark or in other countries, other available data will be used, e.g. migration limits for food contact materials (SML values). For substances where there is no TDI, SML or equivalent toxicological value, the toxicologist carries out a risk assessment based on the toxicity of the substance.
The toxicological risk assessment is a systematic review of the chemical substance's possible health-damaging effects in humans when low doses are taken orally over a long period of time, e.g. carcinogenic or reproductive toxic properties.
Published data from e.g. animal studies, in vivo tests and in silico tests are used to assess the toxicity of the substances. This means, among other things, that DHI also uses QSAR and 'read across' when necessary. With QSAR (Quantitative Structure-Activity Relationship) and 'read across', the substance is compared with similar substances (e.g. with the same functional chemical group, physical/chemical data, etc.).
Data from comparable substances is thus used in the assessment.
The acceptance requirement is based on this data and includes safety factors that were used when determining the quality criterion. The assessment is based on the method of toxicological risk assessment according to European legislation (REACH, guidance on risk assessment).
Since material manufacturers are constantly developing the existing and new raw materials, the chemical composition of the materials also changes over time.
This means that you must check the ingredients in the material on a regular basis and assess new substances that you have not previously assessed and analysed for.