NASA astronauts have only managed to live continuously on the International Space Station (ISS) for a year and Biosphere 2 on Earth failed at two years of uninterrupted human habitation. Both cases required extracting the sickened people from the toxic environments. At this point it is ludicrous to talk about a permanent manned base on Mars.
NASA has decades of experience in studying the effects of Sick Building Syndrome (SBS) and their experiments show that continuous habitation of an alien environment in Space results in sickness in less than a year in astronauts and a similar environment on Earth produces ill health in humans in just two years.