Dr Holger M. Koch 1,2

  1. Institute for Prevention and Occupational Medicine (IPA) of the German Social Accident Insurance, Ruhr-University Bochum, Germany.
  2. Queensland Alliance for Environmental Health Sciences, The University of Queensland, Brisbane, Australia

In my talk, I will describe the general approach of human biomonitoring (HBM) to determine human exposure to (environmental) chemicals and explain how sound risk assessments can be made based on HBM data. HBM is the only tool that comprehensively covers all sources and pathways of exposure and can help to understand the individual cumulative body burden of potentially harmful chemicals.

Developing new HBM methods and approaches requires a profound understanding of the chemicals' human metabolism and excretion. This knowledge is essential for choosing the best biomarkers in terms of sensitivity and selectivity, as well as for interpreting their measured concentrations in terms of doses taken up and toxicological relevance.

Exposure biomarker data can be used to “simply” compare different subpopulations, e.g., children versus adults, men versus women, rural versus urban areas, but also regions, countries, or continents, or to identify exposure hotspots. When collected regularly, biomarker data can also provide excellent information on temporal trends in exposure. In epidemiological studies, HBM data can be used to uncover associations with health effects. When combined with PBPK data, reverse dosimetry allows the calculation of (daily) intake levels, which can then be compared to health-based guidance values such as tolerable daily intakes (TDI) or animal-based points of departure (PODs).

Thus, HBM data are extremely valuable not only for exposure assessment but also for both risk assessment and risk management, as they allow rapid identification of exposure hotspots, emerging chemicals of concern, and provide information on whether individual or cumulative exposures (across all known or unknown sources and pathways) exceed permissible levels and warrant intervention.

Using specific examples of new or emerging chemicals such as phthalate-substituting plasticizers, novel UV filters, legacy nonylphenol, and other plastics-related chemicals such as bisphenols, I will describe how valuable and robust novel exposure biomarkers can be identified based on (human) metabolism studies, how analytical methods are developed, and how these methods are applied in population samples.