Hi JaSin,
Google AI:
Water on Mars is polluted with perchlorates,
which are toxic salts that lower the freezing point of water, allowing it to remain liquid on the Martian surface. This salty, briny water can also contain other salts like chlorides and sulfates of sodium, magnesium, and calcium. Before use, this water would require significant detoxification to remove these contaminants for both human health and equipment corrosion prevention.
Perchlorates: The primary contaminant, perchlorates are toxic salts that are also corrosive to equipment. They are abundant on Mars and can absorb water from the atmosphere, forming liquid brines.
Other salts: The water also contains other salts like sulfates and chlorides of elements such as sodium, magnesium, and calcium.
Why it's liquid: The high concentration of these salts lowers the freezing point of the water, allowing it to exist as a liquid even at Mars' very low temperatures, in a process similar to how salt is used to de-ice roads on Earth.
Health and equipment concerns: Because these perchlorates are toxic to humans and corrosive to equipment, the water would need to be purified before it could be used for drinking, food production, or propellant manufacturing.