How ignorant are you. In a thermal power station the water used to generate the steam is ultra pure. It goes through filtration, floculation, ionisation and degassing. It is in a closed system and the only release is from small leaks or occasional blow downs. Water used for cooling is not tested and in many cases is pumped directly from the river or ocean, passed through the condensers and returned to its original source uncontaminated with at most an increase in temperature. Get your facts correct.