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Genotoxicity of size‐fractionated samples of urban particulate matter
Author(s) -
Healey Katherine,
Lingard Justin J.N.,
Tomlin Alison S.,
Hughes Adam,
White Kay L.M.,
Wild Christopher P.,
Routledge Michael N.
Publication year - 2005
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/em.20105
Subject(s) - comet assay , genotoxicity , dna damage , particulates , chemistry , dna , environmental chemistry , microbiology and biotechnology , toxicity , biology , biochemistry , organic chemistry
Urban particulate matter (UPM) includes particles of size smaller than 10 μm (PM 10 ), which may impact on human respiratory and cardiovascular health. It has been reported previously that PM 10 can induce DNA damage. We have collected size‐fractionated PM 10 at the roadside and measured the induction of DNA damage by different‐sized UPM using the alkaline Comet assay and the plasmid strand‐break assay. We found that foil disks were more suitable for collecting UPM than quartz fiber filters, as the UPM could be easily extracted from the foil disks and accurately weighed. Using the Comet assay, all size fractions induced DNA damage in A549 lung epithelial cells, with the finer fractions (D 50% = 0.65 μm and lower) inducing the most damage. In the plasmid strand‐break assay, in which DNA damage is induced by free‐radical species generated in solution, the most damage was also induced by the finer fractions, although the finest fraction (D 50% < 0.43 μm) did not induce as much damage as D 50% = 0.65 and 0.43 μm. When an organic extract of a standard UPM sample was compared to the whole particles and the washed particles in the Comet assay, it was found that around 75% of the damage induced by the whole UPM could be induced by the organic extract. These results show that finer particulates have the greatest ability to induce DNA damage in lung epithelial cells and naked DNA, and that both organic and inorganic components of the UPM contribute to its genotoxic effects. Environ. Mol. Mutagen., 2005. © 2005 Wiley‐Liss, Inc.