Background exposure versus additional exposure in human biomonitoring

Abstract

Due to the improved analytical methods, it is now possible to measure in man hazardous chemicals or their activation products in human blood and tissues. Biomarkers have been identified whose tissue level reflects the internal exposure resulting from all sources of uptake – including the contribution of endogenously occurring products (biological monitoring). One step further to risk assessment is the measurement of protein and DNA adducts (biochemical effect monitoring) which reflects the body burden with reactive metabolites. Applying these methods it turned out that in most cases not only the exposed but also not knowingly exposed controls had significant adduct levels. This raised questions about the existence of background exposures and their role for risk assessment.