| Human Toxicity Excerpts | /HUMAN EXPOSURE STUDIES/ Bronchoalveolar lavage (BAL) cell and cytokine concentrations, pulmonary function, and peripheral blood neutrophil concentrations /were quantified/ in 6 healthy volunteers 18-20 hr after inhalation of fine and ultrafine magnesium oxide particles produced from a furnace system model. ...Postexposure studies /were compared/ with control studies from the same 6 subjects. Mean +/- standard deviation (SD) cumulative magnesium dose was 4,138 +/- 2,163 min x mg/cu m. By weight, 28% of fume particles were ultrafine (<0.1 micron in diameter) and over 98% of fume particles were fine (<2.5 micron in diameter). There were no significant differences in BAL inflammatory cell concentrations, BAL interleukin (IL)-1, IL-6, IL-8, tumor necrosis factor, pulmonary function, or peripheral blood neutrophil concentrations postexposure compared with control. ... /These/ findings suggest that high-dose fine and ultrafine magnesium oxide particle exposure does not produce a measurable pulmonary inflammatory response. These findings are in marked contrast with the well-described pulmonary inflammatory response following zinc oxide particle inhalation. ... /It was concluded/ that fine and ultrafine particle inhalation does not result in toxicity in a generic manner independent of particle composition./HUMAN EXPOSURE STUDIES/ Ambient air particulates derived from a magnesite-processing plant contain magnesium oxide (85-90%), iron oxide (7-8%), calcium oxide (about 2.5-3%), Al- and Si oxides (0.1-0.5%) as well as additional elements in trace amounts as follows: Ni, Cr, Mn, Co, Hg, Cd, Pb, V, Ba, Ag, Cu and Sn. Magnesite clinker is manufactured from raw magnesite by baking in rotary furnaces using the Leseps-Polysius system, which represents the source of particulate pollutants entering the atmosphere. In the area heavily polluted by magnesite particles, the health impact using the data obtained from the exposed humans and animals was assessed. The reason for this study were the data on the increased frequency of respiratory diseases in children in the polluted area. In a group of children (9-10 years of age) residing in the area, the immune response to ambient air pollutants exposure in comparison to a non-exposed group living outside the polluted area was investigated. A statistically significant decrease in the amount of salivary lysozyme, SlgA, IgG and albumin in the exposed group was observed. .../HUMAN EXPOSURE STUDIES/ Examination of 95 workers exposed to an unspecified concentration of MgO dust revealed slight irritation of the eyes and nose. ... Conjunctivitis, nasal catarrh, and coughing up discolored sputum /was cited/ after industrial exposures, but even when such exposures doubled serum magnesium as compared to normal concentrations, no systematic effects were noted amoung these workershowever, serum calcium concentrations were elevated./HUMAN EXPOSURE STUDIES/ ... Four volunteers ...were exposed for 1-9 min to freshly generated /magnesium oxide/ fume at 410, 420, 430, or 580 mg/cu m. Although slight reactions were observed after <10 min of exposure at these concns, it was believed that increased exposures would lead to more severe reactions. Inhalation of magnesium oxide produced a febrile reaction and a leukocytosis, similar to metal fume fever, in the exposed subjects analogous to that caused by inhalation of zinc oxide.For more Human Toxicity Excerpts (Complete) data for MAGNESIUM OXIDE (10 total), please visit the HSDB record page. |
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