A bad mix: exposure may be "safe" only with one chemical at a time.

A bad mix: exposure may be "safe" only with one chemical at a time.
http://www.environmentalhealthnews.org/ehs/newscience/bad-mix-exposures-safe-only-one-chemical-at-a-time#do

"Exposure to a mixture of pollutants found in food, water and air have more severe effects than each chemical alone.
Exposure to a mixture of environmental chemicals is far more harmful to male rats than exposure to the individual chemicals would predict, even when the level of each contaminant in the mixture causes no effect by itself. The results indicate that assessing the risk of chemicals one-compound-at-a-time will underestimate potential harm. People are exposed to hundreds of chemicals at a time, if not more.  People could be affected by mixtures of chemicals that are currently considered "safe" based on their individual toxicities."

Christiansen S, M Scholze, M Dalgaard, AM Vinggaard, Marta Axelstad, Andreas Kortenkamp and Ulla Hass. Synergistic disruption of external male sex organ development by a mixture of four antiandrogens. Environmental Health Perspectives doi:10.1289/ehp.0900689.  http://www.ehponline.org/docs/2009/0900689/abstract.html