2023-08-08 バーミンガム大学
◆この発見は、将来の宇宙船の設計と建設に影響を与え、初期段階での材料の選択により多くの汚染源を排除する可能性があります。発見された汚染物質には、有害なものも含まれており、特に炎症抑制剤として使用されるフルオロ化合物などが含まれています。
◆宇宙ステーション内の空気は常に循環されており、CO2とガス状の微小な汚染物質が除去されますが、BFRsなどの化学物質がどの程度除去されるかは不明です。高いイオン化放射線は材料の老化を加速させ、プラスチック製品がマイクログラビティ環境で微小およびナノプラスチックに分解され、空中に浮遊する可能性があります。このため、ISSの塵中のPBDEs、HBCDD、NBFRs、OPEs、PAH、PFAS、およびPCBsの濃度や相対的な存在量は、地球上の室内マイクロ環境の塵とは異なる可能性があります。
＜関連情報＞
- https://www.birmingham.ac.uk/news/2023/chemical-contamination-on-international-space-station-is-out-of-this-world
- https://pubs.acs.org/doi/10.1021/acs.estlett.3c00448
国際宇宙ステーションの塵に含まれる残留性有機汚染物質 Persistent Organic Contaminants in Dust from the International Space Station
Stuart Harrad, Mohamed Abou-Elwafa Abdallah, Daniel Drage, and Marit Meyer
Environmental Science and Technology Letters Published:August 8, 2023
DOI:https://doi.org/10.1021/acs.estlett.3c00448
Abstract
Polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD), “novel” brominated flame retardants (NBFRs), organophosphate esters (OPEs), polycyclic aromatic hydrocarbons (PAH), perfluoroalkyl substances (PFAS), and polychlorinated biphenyls (PCBs) were measured in a composite sample of dust from the International Space Station (ISS). Notwithstanding the unique environment from which the dust originated, while concentrations of all target compound classes frequently exceeded the median values in terrestrial indoor microenvironments in the US and western Europe, ISS dust concentrations were generally within the terrestrial range. The relative abundance of the three HBCDD diastereomers is dominated by γ-HBCDD (96.6% ΣHBCDD). This matches very closely with the commercial mixture added to materials and contrasts with the diastereomer distribution observed in most terrestrial indoor dust samples (in which γ-HBCDD is typically ∼60–70% ΣHBCDD). This suggests conditions inside the ISS do not favor the previously reported photolytically mediated formation in dust of α-HBCDD. Also of note, the concentration of perfluorooctanoic acid (PFOA) in ISS dust (3300 ng/g) exceeds the maximum reported (1960 ng/g) in a 2008 survey of dust from US child daycare centers and homes. This may reflect the widespread use of waterproofing treatments in the ISS to prevent microbial growth. Our findings can inform future material choices for manned spacecraft such as the ISS.
