Comet assay application in environmental monitoring: DNA damage in human leukocytes and plant cells in comparison with bacterial and yeast tests

Urban airborne particulate is a complex mixture of air pollutants, many of which have not been identified, However, short-term mutagenesis tests toget her with chemicophysical parameter analysis are able to better assess air q uality and genotoxic load. The findings of continuous monitoring (January 1 991-August 1998) of urban air genotoxicity of a Po Valley town (Italy) on S almonella typhimurium and Saccharomyces cerevisiae are reported. During thi s period, various measures (catalytic devices, unleaded fuels, annual vehic le overhaul, etc.) to improve air-dispersed pollutant control were enforced . However, a continuous presence of genotoxic compounds is shown and more q ualitative than quantitative changes are evident, We also demonstrate the a bility of the Comet assay to detect DNA-damaging agents in airborne particu late samples. We applied the test to human leukocytes and, with major impro vements, to plant cells (Allium cepa roots and epigean tissues of Impatiens balsamina). The first findings on human leukocytes confirm the sensitivity of this assay, its peculiarity and its applicability in assessing genotoxi city in environmental samples. The capability of plants to show the respons e of multicellular organisms to environmental pollutants largely counterbal ances a probable lowering in sensitivity. Moreover, application of the Come t test to epigean tissues could be useful in estimating the bioavailability of and genotoxic damage by air pollutants, including volatile compounds (o zone, benzene, nitrogen oxides, etc.) to higher plants.