The surface of the moon is dusty 鈥� and nasty. The Apollo astronauts quickly learned that the sharp grains of moon dust could tear spacesuits and irritate their lungs, but now it seems the lunar surface is even worse for human health than we thought.
By studying lunar dust samples brought back by astronauts, we discovered that they contain certain minerals that are known to quickly react with human cells and generate toxic hydroxyl radicals. These hydroxyl radicals have previously been linked to lung cancers.
To estimate how many radicals would be produced in humans after exposure to lunar dust, Donald Hendrix at Stony Brook University and his colleagues soaked olivine and augite, two iron-based compounds found on the moon, in a liquid that simulates human lung fluid.
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After 15 minutes the two rocks had released about nine times more hydroxyl radicals per litre of fluid than quartz, a highly toxic, silicon-based compound.
鈥淭he fine metallic iron is extremely hazardous to human health,鈥� says Hendrix. He suggests these minerals can easily enter human system and produce large quantities of radicals.
Because of the limited supply of lunar dust, the study used similar rocks found on Earth, which contain less reactive 聽minerals, he says. So, the damage from real lunar dust may be more severe.
鈥淚t鈥檚 a major health concern for future astronauts,鈥� says Hendrix, who at the American Geophysical Union meeting in Washington, D.C. this week.
Cort Anastasio at University of California, Davis, says that it鈥檚 not enough to just look at simulated lung fluid 鈥� further research is needed to determine the dust鈥檚 toxicity to real human lungs.
鈥淭he generation of radicals by metals is highly dependent on the fluid characteristics,鈥� he says. 鈥淥ur lungs have defences against these free radicals, so it鈥檚 difficult to assess the toxicity of a given amount of hydroxyl radicals.鈥�
