Options
2016
Journal Article
Titel
Method for identification of low soluble, biopersistent dusts (GBS)
Titel Supplements
Abstract
Abstract
Respirable biopersistent granular dusts (GBS) show a negligible solubility in physiological lung fluid and do not exhibit a specific surface chemistry-related toxicity at volumetric non-overload conditions in lungs. The German MAK Commission proposed a TLV of 0.3 mg/m3 for GBS excluding any adverse lung effects upon chronic exposure (no volumetric lung overload). OBJECTIVES: Determination of a value of 'low solubility' and analysis of the inflammatory response in lungs including micro-/nanoscaled dusts. For TiO2 (rutile-micro), TiO2 (anatase-nano), Eu2O3 (micro-nano mixed), BaSO4 (micro), ZrO2 (micro) and amorphous SiO2 (nano) the solubility (day 3, 28 and 90) and inflammation (day 3 and 28) after intratracheal instillation in rats was analysed. Two doses of 0.5 (non-overload) and 1.5 ml (moderate overload) were administered. The differential cell count showed only slight inflammatory cell levels after treatment with TiO2 (rutile) and BaSO4. In contrast, the TiO2 (anatase) showed a stronger response. The rare earth Eu2O3 dust showed the strongest effect including a red-coloured lung lavage fluid. ZrO2 and amorphous SiO2 showed a strong acute response after 3 days, however, recovered mostly completely within 28 days. These data were validated by parallel subacute inhalations at same lung loads. GBS have to fulfill a 'low solubility' and a 'non-significant inflammatory response'. Unlike as the microscaled most nanoscaled dusts will not meet these criteria and an individual toxicological characterization seems to be necessary for this particle class.