Toxicity of lunar dust assessed in inhalation-exposed rats
Authors: Lam, Chiu-wing1; Scully, Robert R.1; Zhang, Ye2; Renne, Roger A.3; Hunter, Robert L.4; McCluskey, Richard A.5; Chen, Bean T.6; Castranova, Vincent6; Driscoll, Kevin E.7; Gardner, Donald E.8; McClellan, Roger O.9; Cooper, Bonnie L.10; McKay, David S.10; Marshall, Linda2; James, John T.1
Source: Inhalation Toxicology, Volume 25, Number 12, October 2013 , pp. 661-678(18)
Publisher: Informa Healthcare
Humans will again set foot on the moon. The moon is covered by a layer of fine dust, which can pose a respiratory hazard. We investigated the pulmonary toxicity of lunar dust in rats exposed to 0, 2.1, 6.8, 20.8 and 60.6 mg/m3 of respirable-size lunar dust for 4 weeks (6 h/day, 5 days/week); the aerosols in the nose-only exposure chambers were generated from a jet-mill ground preparation of a lunar soil collected during the Apollo 14 mission. After 4 weeks of exposure to air or lunar dust, groups of five rats were euthanized 1 day, 1 week, 4 weeks or 13 weeks after the last exposure for assessment of pulmonary toxicity. Biomarkers of toxicity assessed in bronchoalveolar fluids showed concentration-dependent changes; biomarkers that showed treatment effects were total cell and neutrophil counts, total protein concentrations and cellular enzymes (lactate dehydrogenase, glutamyl transferase and aspartate transaminase). No statistically significant differences in these biomarkers were detected between rats exposed to air and those exposed to the two low concentrations of lunar dust. Dose-dependent histopathology, including inflammation, septal thickening, fibrosis and granulomas, in the lung was observed at the two higher exposure concentrations. No lesions were detected in rats exposed to ≤6.8 mg/m3. This 4-week exposure study in rats showed that 6.8 mg/m3 was the highest no-observable-adverse-effect level (NOAEL). These results will be useful for assessing the health risk to humans of exposure to lunar dust, establishing human exposure limits and guiding the design of dust mitigation systems in lunar landers or habitats.
Document Type: Research Article
Affiliations: 1: 1Space Toxicology Office, NASA Johnson Space Center, Houston, TX, USA, 2: 2Wyle Science, Technology & Engineering Group, Houston, TX, USA, 3: 5Roger Renne ToxPath Consulting Inc., Sumner, WA, USA, 4: 3Department of Pathology and Laboratory Medicine, University of Texas Medical School, Houston, TX, USA, 5: 6Naval Hospital Pensacola, Pensacola, FL, USA, 6: 7Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA, 7: 8PGT Healthcare, Geneva, Switzerland, 8: 9Inhalation Toxicology Associates, Savannah, GA, USA, 9: 10Toxicology and Human Health Risk Analysis, Albuquerque, NM, USA, 10: 11Astromaterials Research and Exploration Systems, NASA Johnson Space Center, Houston, TX 77058, USA,
Publication date: October 1, 2013
- In this: publication
- By this: publisher
- In this Subject: Internal Medicine
- By this author: Lam, Chiu-wing ; Scully, Robert R. ; Zhang, Ye ; Renne, Roger A. ; Hunter, Robert L. ; McCluskey, Richard A. ; Chen, Bean T. ; Castranova, Vincent ; Driscoll, Kevin E. ; Gardner, Donald E. ; McClellan, Roger O. ; Cooper, Bonnie L. ; McKay, David S. ; Marshall, Linda ; James, John T.