- Future astronauts who visit Mars would
be well-advised not to drink the water, based on new findings that show
dangerous levels of lead and chromium on the Red Planet.
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- Researchers presented a study based on
their work Thursday at the Lunar & Planetary Science Conference in
Houston.
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- "This water would definitely violate
U.S. Environmental Protection Agency limits for potability," says
Allen Treiman, a meteorite expert at the Johnson Space Center. "Fortunately,
any Mars colony should have a pure supply of drinking water handy, if they
just melt the ice."
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- Treiman conducted an intense search for
known minerals on a Martian meteorite called EETA 79001, found in Antarctica
in 1979. His findings suggest they were deposited by groundwater containing
dangerous levels of lead and chromium. Martian ice, however, most likely
formed from water vapor, without picking up the toxic substances Treiman
says may taint any wells dug on the Red Planet.
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- But the bad groundwater could provide
useful clues to Martian geology.
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- A study a decade ago on the same meteorite
found evidence of lead, chromium, and sulfur in grains in the rock that
appeared to have been deposited by water, but the exact ratio of these
elements --- and thus the chemical substance that formed the deposits --
remained unknown. Reinterpreting this earlier analysis of the grains, Treiman
matched them to a rare mineral called phoenicochroite (pronounced "feena-co-crow-ite").
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- On Earth, this bright orange mineral
occurs naturally above some lead deposits in Arizona and has been found
in soils downstream of chrome plating plants. While there's no evidence
of industrial pollution on Mars, the mineral might indicate deposits of
lead or other heavy metals, at least in the region where the meteorite
originated.
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- Although space colonists would have to
melt ice for a drink, Treiman's study doesn't negate the possibility of
life on ancient Mars. On Earth, he points out, microbes often colonize
poisonous mine tailings. But even if it wasn't toxic, the mineral would
probably kill any NASA plans for selling bottled Mars-water: It also tastes
bad.
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- "This is nasty stuff," Treiman
says. "You definitely wouldn't want to drink it." The tainted
water would be unusually bitter, with a very high pH.
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- "It wouldn't taste quite as alkaline
as the ammonia under your sink," he says, "but it would come
close."
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