NEW MODEL FOR HEALTH EFFECTS OF AIR-POLLUTANTS - EVIDENCE FOR SYNERGISTIC EFFECTS OF MIXTURES OF OZONE AND SULFURIC-ACID AEROSOLS ON RAT LUNGS

  • 1 January 1978
    • journal article
    • research article
    • Vol. 91  (2) , 328-339
Abstract
Chronic respiratory disease-free rats were exposed to relatively low levels of O3 (0.4-0.5 ppm) and H2SO4 aerosols (11-3000 .mu.g/m3) and to mixtures of these pollutants. Exposure effects on conducting airway metabolism were evaluated as rate of secretion of mucus glycoproteins by tracheal explants and on lung homogenates (predominantly lung parenchyma) by various chemical assays. True synergism was observed in that the response to the mixture of gases exceeded the sum of effects observed with the same concentration of either gas alone. Wet to dry weight ratios; DNA, protein and RNA content; and the activities of various lysosomal hydrolases in the lung homogenate all increased on exposure to O3-H2SO4 mixtures concomitant with observed increases in the rate of secretion of mucus glycoproteins by tracheal explants from the same rats. All of these effects are probably reversible when rats are allowed to recover after exposure. The lack of toxicity noted on exposure of experimental animals to individual pollutant gases at near-ambient levels should be interpreted with caution, since there is now epidemiological, physiological and biochemical evidence that mixtures of pollutant gases may show synergistic effects.

This publication has 4 references indexed in Scilit: