Info on Chrome +6.
http://www.cdc.gov/niosh/topics/hexchrom/
http://www.epa.gov/safewater/contami...mium.html#four
http://www.clu-in.org/contaminantfoc..._and_Guidance/
http://www.epa.gov/nrmrl/pubs/625r00005/625r00005.pdf
That will make yer head spin. Each body of water has different standards.
http://www.epa.gov/waterscience/meth...files/1636.pdf