Benchmark approach and dose-response modelling in toxicological risk assessment: new projects at FoBiG
The benchmark approach makes use of all dose-response data observed in a toxicological study and allows for a description of data uncertainty. Therefore, the benchmark approach is superior to the NOAEL as a point of departure for risk characterisation.
Dose-response modelling is of importance also for carcinogenic substances. With major contributions from Fritz Kalberlah, who is member of UA III and chairman of the ad-hoc working group “Krebsrisikozahlen”, the “Ausschuss für Gefahrstoffe” of the German Federal Ministry of Work and Social Affairs established a methodology to derive risk-based values for assessing exposure to carcinogenic substances at the workplace. This methodology includes dose-response modelling to determine a point of departure (the respective guide is available from the website of the German Federal Institute for Occupational Safety and Health).
Similarly, FoBiG is currently developing a methodology for assessing carcinogenic substances in indoor air on behalf of the State Northrhine-Westphalia.
In another project on behalf of the German Federal Environmental Agency (UBA), FoBiG develops a guidance document for applying the benchmark approach to derive effect-related human biomonitoring values (HBM values, see the website of the Federal Environmental Agency for more information).


New article on mechanisms of action
FoBiG has recently described basic (toxicologically relevant) biochemical and cellular mechanisms of action in a research project for the German Federal Environmental Agency. Data on the so-called toxicity pathways can lead to the discovery of "new" endpoints that are toxicologically meaningful. In addition, the number of animal experiments can be reduced with the aid of such data and the assessment of mixtures can be based on a new foundation. Some of the results of this research project are now published in a journal article.


Assessment of nitrogen trichloride in indoor swimming pools
Nitrogen trichloride (trichloramine, TCA) is generated during chlorination of swimming pool water in the presence of organic nitrogen sources such as urea. The volatile substance evaporates easily from water and is considered to be responsible for the typical “chlorine smell“ in swimming pools. TCA is irritating to the eyes and the upper respiratory tract. Furthermore, TCA is suspected of causing asthma in swimming pool attendants and users. Regulation of indoor TCA concentrations was therefore considered important. FoBiG, under contract of the German Federal Environment Agency (UBA), has recently summarised measured concentrations of TCA in the air of indoor swimming pools and evaluated the toxicological data for the substance. The report (in German with English abstract) is available here.