As geothermal steam containing contaminants such as boron, arsenic, and mercury is passed through a turbine-condenser system, the contaminants preferentially collect in the initial condensate produced from the steam. Collecting this initially-produced condensate and segregating it from the remainder of the steam being condensed ensures that condensate produced from the remainder of the steam is contaminants-lean, preferably containing the contaminants in concentrations allowing for discharge of the contaminants-lean condensate to the environment.