| Exogenous zinc (Zn) is emerging as a serious contaminant in the environment. Yearly deposition of zinc particles line heavily traveled inner city roadways and less traveled rural roadways. Particle size for zinc ranges from approximately PM10 to PM 2.5 microm or less. These fine particles contain microscopic solids or liquids that can cause serious health problems. PM10 are considered to be "thoracic" sized particles, with the mass fraction of inhaled particles penetrating beyond the larynx. Whereas, PM2.5 are considered to be "respirable" sized particles, with the mass fraction of inhaled particles penetrating to the unciliated airways. Exogenous zinc can be used as a quantifiable marker to contrast the differences in exposures in canines originating from urban and rural environments. These exposures are analyzed using a scanning electron microscope with energy dispersive X-ray spectrometry, and usage of a morphometric point counting method for a physical count and categorization of composition of inhaled retained particle content. |
