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my local grocery store started selling rhubarb with the leaves cut off because they were worried (so says the guy in the produce dept) that people wouldn't know to eat the stalks instead of the...

Try "Ranking Possible Carcinogenic Hazards" by BRUCE N. AMES,* RENAE MAGAW, Lois SWIRSKY GOLD. SCIENCE, VOL. 236, April 17, 1987, pp 271-280. You can find that at www.sciencemag.org for a fee.
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