....toxicity due to the presence of perchlorates.....
So, the Martian soil is loaded with ROCKET FUEL?
Good, now they won’t have to take any with them...............................
[snip] Perchlorate is a negatively charged molecule made of one chlorine atom and four oxygen atoms. Perchlorate can occur naturally or be man-made. [/snip]
https://www.fda.gov/food/environmental-contaminants-food/perchlorate-questions-and-answers
OTOH:
https://en.wikipedia.org/wiki/Ammonium_perchlorate_composite_propellant