A groundbreaking study has unveiled a startling revelation about the chemical contamination present on the International Space Station (ISS)—it surpasses the levels found in household floor dust across the United States and Western Europe. By analysing dust samples collected by the station's air filtration system, researchers have shed light on potential risks and possible implications for future space exploration.

Figure 1. Chemical Contamination of the International Space Station

The study identified a variety of organic contaminants within ISS dust, notably surpassing the average levels found in house dust across the U.S. and Western Europe. Among these contaminants were polybrominated diphenyl ethers (PBDEs), commonly employed as flame retardants in electrical equipment [1]. The presence of PBDEs on the ISS could be linked to the utilization of inorganic flame retardants, like ammonium dihydrogen phosphate, to imbue fabrics and webbing with flame-resistant properties. While PBDE concentrations in ISS dust samples technically align with those in U.S. house dust, the implications are thought-provoking. The insights gained from this study urge a revaluation of materials used in space station construction to ensure the well-being of astronauts and the integrity of future space habitats.

Researchers note that PBDE concentrations in the dust sample falling within the range of concentrations detected in US house dust 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 potential sources of many of the chemicals detected.

Air inside the ISS is constantly recirculated with eight to 10 changes per hour. While CO2 and gaseous trace contaminant removal occurs, the degree to which this removes chemicals like BFRs is unknown. [2] High levels of ionizing radiation can accelerate aging of materials, including breakdown of plastic goods into micro and nano plastics 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.

Scientists measured concentrations of a range of target chemicals in dust collected from the ISS. In a microgravity environment, particles float around according to ventilation system flow patterns, eventually depositing on surfaces and air intakes. Screens covering the ISS HEPA filters accumulate this debris, requiring weekly vacuuming to maintain efficient filtration. Material in ISS vacuum bags comprise of previously airborne particles, clothing lint, hair and other debris generally identified as spacecraft cabin dust. Some vacuum bags were returned to Earth for studies of this unique dust, with a small sample shipped to the University of Birmingham for analysis in the study.

References:

1. https://www.space.com/chemical-contaminant-levels-discovered-on-international-space-station
2. https://phys.org/news/2023-08-chemical-contamination-international-space-station.html

Cite this article:

Janani R (2023), Beyond Earthly Bounds: The Troubling Chemical Contamination of the International Space Station, Anatechmaz, pp.472