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| A toxicological study based on DNA damage of inhalable particulates collected in Macao during winter. |
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Abstract Plasmid DNA assay was applied to study oxidative capacity of the winter PM10 in Macao. The PM10 samples were collected at three sites, including the Sun Yat Sen Municipal Park site (SYSP) and the Av. de Horta e Costa site (AHC) in the Macao Peninsula as well as the Macao University site in the Taipa Island (TI). The TD30 values (the dosage of PM10 that caused 30% DNA damage) of the PM10 were relatively lower at the SYSP site, followed by the AHC site, with the TI site to be the highest, demonstrating that the PM10 in the Macao Peninsula had a higher toxicity than that of the Taipa Island. Field emission scanning electron microscopy (FESEM) and image analysis were used to analyse the morphology and size distribution of individual particles in PM10, and these microscopic characteristics were further combined with the oxidative capacity of PM10. A higher proportion of secondary particles and unknown ultrafine particles were associated with the lower TD30 values of PM10. The secondary particles and unknown ultrafine particles might be the important components responsible for the observed plasmid DNA damage. The water-soluble fractions and intact whole particle solutions of Macao airborne particles produce a similar plasmid assay, demonstrating that the oxidative damage by the particles in Macao was mainly sourced from the water-soluble fraction.
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Received: 19 January 2009
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