ISS dust found to be highly contaminated with chemicals

In a new study conducted by the University of Birmingham in partnership with NASA’s Glenn Research Centre, scientists analysed a sample of dust from air filters within the ISS. The team found levels of organic contaminants which were higher than the median values found in US and Western European homes.

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Contaminants found in the ‘space dust’ included polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD), ‘novel’ brominated flame retardants (BFRs), organophosphate esters (OPEs), polycyclic aromatic hydrocarbons (PAH), perfluoroalkyl substances (PFAS), and polychlorinated biphenyls (PCBs). The work is published in Environmental Science and Technology Letters.

“Our findings have implications for future space stations and habitats, where it may be possible to exclude many contaminant sources by careful material choices in the early stages of design and construction,” said study co-author Professor Stuart Harrad, from the University of Birmingham. 

“While concentrations of organic contaminants discovered in dust from the ISS often exceeded median values found in homes and other indoor environments across the US and Western Europe, levels of these compounds were generally within the range found on Earth.”

The researchers noted that PBDE concentrations in the dust sample may reflect use on the ISS of inorganic FRs like ammonium dihydrogen phosphate to make fabrics and webbing flame retardant. They believe that the use of commercially available ‘off-the-shelf’ items brought on board for the personal use of astronauts, such as cameras, MP3 players, tablet computers, medical devices, and clothing, are also potential sources of many of the chemicals detected.

Air inside the ISS is constantly recirculated with 8-10 changes per hour. While CO2 and gaseous trace contaminant removal occurs, the degree to which this removes chemicals like BFRs is unknown. High levels of ionizing radiation can accelerate ageing of materials, including breakdown of plastic goods into micro and nanoplastics that become airborne in the microgravity environment. This may cause concentrations and relative abundance of PBDEs, HBCDD, NBFRs, OPEs, PAH, PFAS, and PCBs in ISS dust to differ notably from those in dust from terrestrial indoor microenvironments.