- A Good Overview (though slightly back-dated): Quantitative assessment of worldwide contamination of air, water and soil by trace metals 
- A summary of Pollutants from the EPA 
- MCL: 5 ppb
- MCLG: 5 ppb
- Known Carcinogen
- Cadmium Contamination Sites
- Ishihara T, Kobayashi E, Okubo Y, Suwazono Y, Kido T, Nishijyo M, Nakagawa H, and Nogawa K. . pmid:11376862.
- Plachimada, India: 
- statistics on Pb, Cd, Cr levels in well water surrounding a Coca-Cola plant (2006)
- pictures too :)
- Most recent(June06) paper on e.coli bioaccumulation of Cd
- Deng X, Yi XE, and Liu G. . pmid:16890348.
- Heavy Metal Limits
- Staessen JA, Lauwerys RR, Ide G, Roels HA, Vyncke G, and Amery A. . pmid:7911869.
- Satarug S, Baker JR, Urbenjapol S, Haswell-Elkins M, Reilly PE, Williams DJ, and Moore MR. . pmid:12505433.
- MCL: 2 ppb
- MCLG: 2 ppb
- 20 ppb makes the fish mercury buildup significant
- Polluted sites
- Detection (to assess our system):
- Gold Nanoparticles http://www.cah.ucf.edu/news/2005-Mercurynose.php