Biomarkers of the effect of VOC exposure:: Recent developments

Biomarkers are convenient tools to characterize 1) specific human exposure to air pollution, 2) responses of the human organism to exposure, and 3) individual variations of both exposure and response. This paper presents two effect monitoring tests as recent examples to study human responses to exposure and the application of the tests in environmental,epidemiology. The common feature of these test methods is the use of the stable isotope tracer technique as a basic working principle. One of the methods, the in vivo [N-15]methacetin liver function test, has already been approved for use on humans to characterize SO2 load effects on the detoxification capacity of the liver. Its application field has now been extended for use in regions with other air pollution situations such as airborne dust loaded with heavy metals and airborne volatile organic compounds (VOCs). An excellent correlation was seen between dust or SO2 load and liver detoxification capacities. The other method, a new in vitro test system has been developed to characterize the early effects of a VOC as an airborne pollutant on the nitrogen metabolism. Using the cell system Tetrahymena pyriformis and the amino acid [N-15]arginine as a nutrient in the culture medium, the impact of a toluene load can be measured in terms of changes in the ratios and in the N-15 levels of the various metabolites in several pools.