Concentration of Accumulated Trace Element in Human Lungs, with Special Reference to the Correlation between Accumulated Amount and Age

Abstract

A study was made on the trace element concentration in black dust deposited in human lungs which were considered to have been inhaled through air and then intaked into the body. Autopsied lung samples were used for this study. Deposited particulates were separated in dissolving with alkaline solution and were prepared by multiple cycles of ultra-high speed centrifugation. The final residue was then washed using water and acetone and finally dried. The resulting black powder was analyzed using a scanning electron microscope coupled with an X-ray microanalyzer and by neutron activation analysis. In result, Al, Ti, V, Mn, Fe, Zn, Mg, Si and other elements were determined quantitatively and qualitatively. An attempt was made to correlate to contents of several elements with age. Correlation coefficients of V, Al, Fe, Si were positive on 72 samples. On the contrary, that of Mn and Ti were not correlated. This result means that absorption and clearance of Mn into body were considered to be fast. For emphasis of this result, lung tissues with deposited particulate was analyzed by ICP method. The result showed a same tendency on the correlation between accumulated amount of trace element and age in inhaled particulate deposited into lung tissue. These results provided us a valuable information about intake of trace nutrient through inhaled particulates into body.