Just one part per billion can make a Rat grotesque obesity

New research indicates that with some pollutants, drugs, and natural substances, the effects of the toxic substance vary according to dose -- meaning that the results of high doses might mean absolutely nothing when it comes figuring out the effects of lower levels of exposure.

Take, for example, the pair of rats featured prominently in a photo accompanying the study. While in-utero exposure to 100 parts per billion of the estrogenic drug diethylstilbestrol (DES) makes for scrawny adult mice, exposure to just one part per billion causes grotesque obesity, one study found.

Does this mean higher doses of toxics are better for us? Not likely. But it does mean that since most regulation is based on apparently false assumptions, we might have a whole bunch of health standards that are too weak.  Read on Grist Lovers