I ll give you a recent example Fukushima when that blew of radioactivity have migrated over to the west coast of California probably reached further in the interior and a lot of the radioactivity got into the surface water as well as into our a food chain the sources of contamination in our drinking water to fall one what s coming from environmental pollution and to what they add at the treatment plant so I saw more 1st about what is done at the treatment plant the primary goal of water treatment miscible treatment is to make the what a potable to look good and to put certain additives into the water that have been deemed quote beneficial which are really not really harmful for example you have to disinfect the water because there are bacteria in the water the primary disinfectant of choice of the government is chlorine and now the using a combination of chlorine amount and ammonia cool chloramine so they have to disinfect the water because if you drank water that contained the whole