There are large amounts of ice underground on mars. Some are closer to the surface then others. Assuming this ice has been mined and is not safe for human consumption without purification, is it safe for irrigation?

Do the intermixed dust particles provide nutritional value for the plants? Or is the risk of toxins (to both the plant, and the human assuming the plants produces food) too great?

Mars Ice Deposit Holds as Much Water as Lake Superior

with a composition that's 50 to 85 percent water ice, mixed with dust or larger rocky particles.



No one quite knows at the moment. This is the sort of thing, where the actual content of the water, needs to be examined and purification methods tested against it.

In general, distilling the water is one way to get back to pure water, but energy intensive. Many of the purification processes on Earth potentially could be used, but often are large, and energy intensive.

Anyone serious about colonizing Mars would be wise to consider investigating this issue experimentally. The good news is SpaceX who have considered Mars seriously, are planning on a Red Dragon mission (using the 2018 window), that will be the largest payload ever landed on the red planet, and likely will repeat that mission each launch window to do the work they need done.

  • $\begingroup$ Toxins in water on Earth are mostly biological, like virus. Hardly need to consider that on Mars. And I want to remind you that a Red Dragon is heavier than the sum of everything ever landed on Mars to date! $\endgroup$ – LocalFluff Nov 25 '16 at 20:37
  • $\begingroup$ @LocalFluff "Toxins in water on Earth are mostly biological, like virus." Do you have a source on that? Most of the water on Earth is in the oceans, and seawater cannot be used for irrigation due to the salt. Seawater might also contain microbes, but salt is the major bulk of the problem. $\endgroup$ – Andrew Thompson Nov 25 '16 at 23:47
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    $\begingroup$ @AndrewThompson Well, that's a matter of defining "toxic". Dust in water is impractical too. NaCl is hardly toxic. Mars' surface seems to have chlorates that indeed are toxic. And maybe stinking H2S. But on Earth bad water is generally bad because something is living in it that wants to eat humans. $\endgroup$ – LocalFluff Nov 26 '16 at 0:37
  • $\begingroup$ @LocalFluff Well, that's a matter of defining "toxic" toxic definition suggests 'poisonous' or 'poisonous substance'. It seems pretty straight-forward. "But on Earth bad water is generally bad because something is living in it that wants to eat humans." The question is asking about Mars and irrigation of plants. $\endgroup$ – Andrew Thompson Nov 26 '16 at 1:20

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