During one study of the ISS atmosphere, 12 bacterial strains were isolated and fingerprinted
from the ISS water system. The bacteria consisted of common strains and were encountered at
levels below 10,000 colony-forming units/10 cm^2 , which is well below the minimum bacteria
needed to cause illness. This data represents the beginning of ISS habitation and indicates that
the lessons learned from the Mir and Skylab missions were implemented and have been
effective in keeping the ISS a safe place to live and work (Castro 2004).
Solid waste in space must be safely processed and stored in a confined environment. Most of
the solid waste is wet and poses a high risk of culturing the growth of undesirable
microorganisms. Analysis was performed in order to assess potential crew risks resulting from
microbial decay. Results show certain levels of volatile organic compounds, ethylene, methane,
and carbon dioxide. These gases are being contained within the trash compartments,
minimalizing potential risk for crew members (Peterson 2004).
On station, silver is used as a biocidal agent based
on its antimicrobial properties in the potable
water system. Recent studies have shown that
colloidal silver is possibly toxic to humans.
Researchers are currently developing and testing
a simple technique that will enable crew
members to test silver levels in the water system
in less than 2 minutes (Hill 2010).Continual efforts to ensure crew safety will
accompany the lifetime of the ISS. A new type of
air testing was performed in 2010, evaluating
threshold (T) values for 16 adverse health effect
groups. All T levels were within the safe limit. The highest values were found in mucosal limits,
headaches, central nervous system depression, and cardiac sensitization. This evaluation is an
integral tool to NASA’s Lifetime Surveillance of Astronaut Health (James 2012).
PUBLICATION(S)
Checinska A, Probst AJ, Vaishampayan PA, et al. Microbiomes of the dust particles collected
from the International Space Station and Spacecraft Assembly Facilities. Microbiome.
2015;3:50. doi: 10.1186/s40168-015-0116-3.
Willsey GG, Wargo MJ. Extracellular lipase and protease production from a model drinking
water bacterial community is functionally robust to absence of individual members. PLOS ONE.
November 23, 2015;10:e0143617. doi: 10.1371/journal.pone.0143617.
Garcia HD, Tsuji JS, James JT. Establishment of exposure guidelines for lead in spacecraft
drinking water. Aviation, Space, and Environmental Medicine. July 2014;85:715-720. doi:
10.3357/ASEM.3853.2014.
ISS021E010366 – Expedition 21 Commander
Frank De Winne fills a bag with water from the
Potable Water Dispenser in the US
Laboratory/Destiny for analysis. NASA image.