Markers of Exposure to Aromatic Amines and Nitro-PAH

Abstract

An essential step to protect human health from chemicals at the workplace or in the environment was to measure their concentration in the environment and to correlate them with adverse health effects. Tolerance values, like the maximum workplace concentrations (MAK-values), are established on that basis. A next step to improve exposure control was the introduction of human biomonitoring. Measuring the parent chemical or its stable metabolites in biological material, like blood or urine, allowed to assess the internal stress as compared to the external stress given by environmental monitoring. However, the biological activity of chemicals, of genotoxic carcinogens in particular, depends mostly on reactive intermediates generated in the course of metabolic activation. The biologically active dose cannot be assessed from stable metabolites usually measurable in biological metarial, but from the effects they produce. In contrast to „biomarkers of exposure“ the expression „biomarkers of response“ has been introduced. In this category two kinds of markers exist: biochemical effect markers and biological effect markers. The former markers are mainly protein and DNA adducts, the latter mutations, micronuclei, chromosomal aberrations or sister chromatid exchanges. Whereas the biochemical effects are not considered pathological per se, the biological effects can be seen one step further down to disease. However, as a dosimeter for the biologically active dose, adduct measurements are more specific and more sensitive than the biological endpoints. Moreover, they represent the strain of individuals best.