I was wondering why you said ...

I was wondering why you said "removed". If you were wanting to chelate the metal compounds into their elemental state then the RNA microbial group has been doing this for 3 billion years. Sold world wide.  I believe Pat had asked your limits.  If you would check with the International Institute of health and nutrition you will find both are nutrients needed for life. On an old chart I found 3 ppm of Cd is the level for ocean life. .6 ppm is the level for land based life. Pp. is .5 to 8.4 ppm for ocean life. 2,0 to 2.7 ppm for land based life.  Of course if you have an excess you will need to remove it.  But since ocean waters have a level of 13 ppm this would be a nutrient for ocean life.  Too many people misunderstood when told Heavy metals are toxic. They are not only a nutrient but are directly responsible for all immune systems in plant and animals.  If you eat one ice cream cone it is a nutrient/desert. If you try to eat one ton it become toxic to you.  Most waste treatment facilities are 50 years behind in science and technology.