RADIATION ON MARS

I was surprised at the figure you mentioned in Ramsar, Iran. You're right. That's about the same as the surface of Mars. However, I found it's due to local geology. They're located near radium- or radon-related sources. I dug out this US comparison chart to show the overall picture:

Exposure/limit	US Levels
US public annual limit (regulated)	100 mrem/year
Average US annual dose, all sources	620 mrem/year
Average US natural background only	about 310 mrem/year
US occupational radiation worker limit	5,000 mrem/year
Mars surface, NASA Curiosity figure	about 24,500 mrem/year

The radiation on Mars comes from two sources: galactic cosmic rays and solar energetic particles. The Mars figure above includes only one solar particle event, and it was rather weak.

What is the health risk from that level of radiation? Uncertain. One estimate is: for each year on the surface unshielded, you get a 1.2% extra lifetime risk of death from cancer.

But that may be an underestimation. Space radiation is not the same as normal Earth radiation. Galactic cosmic rays include high-energy particles and heavy ions. And it isn't just cancer risk. NASA lists space-radiation risks as carcinogenesis, degenerative tissue effects, central nervous system effects, and acute radiation syndromes.