If these chemicals are produced as the authors postulate, the rate is probably quite slow. If the likely oxidants in the regolith are produced by other mechanisms (e.g. photochemically) then the rates may be even slower. Either way, there has been time in the 3 or 4 billion year arid history of Mars' surface for these to accumulate to the present "observed" (or is that inferred?) level, IF they are not removed by other processes at similar or faster rates.

IF life were present on Mars, even at the surface, it could probably cope with the rate of production and influx of new superoxidants. The threat to life is more from the extreme aridity, the surface radiation environment, and the generally low temperatures which limit reaction rates and hence organic growth.

In a way, we can use the Lovelock Gaia argument here and observe that SINCE there are such abundances of observed/inferred superoxidants then there is NOT any near-surface life (as we know it, Jim) BECAUSE if there were near surface life, it would cope with and neutralise these compounds quite effectively. (Or it would scavenge them and utilise them in its own metabolism, rather than leaving an energy-rich resource scattered across the surface regolith).

(In an extreme form of the argument, you could argue that the superoxide IS life, of a form that we don't know about on Earth, but I'm not brave enough to go that far today!)

Chris, have you exposed DRY aluminium to dry particles with superoxide activity? I suspect that the natural oxide skin that forms on all aluminium would be ample defence against such a material. Our moist, Oxygen-rich, temperate atmosphere is a significant challenge to reduced metals. Iron rusts spectacularly on Earth, but Raw aluminium does not.

Anodised Aluminium is even more resistant to chemical attack and also to mechanical abrasion - which may be the major threat on Mars. I suspect you'll find that the rover parts have had some form of surface treatment to armour them against likely insults on Mars.

(Would that we could all have such treatment - there would be fewer flames!)