Monday, October 31, 2011

From Salami to Soda Pop: What Does “Toxic” Really Mean?

It started out as a crazy stunt — a gag to keep commuters entertained. DJs at KDND-FM Sacramento had lined up 20 volunteers for a water-drinking contest. Whoever drank the most water without urinating would take a Nintendo Wii home as a prize.

Jennifer Strange was 28 and the mother of three children; she’d entered the contest to win the game player for her kids. Several hours into the event, she started to complain about the pain in her head, and by the time it was over, her belly was protruding so badly she looked pregnant. The DJs thought it was funny. She left the station crying, the pain in her head growing worse all the time.

She was found dead that afternoon; poisoned by water.

Ms. Strange’s tragic story illustrates a peculiar fact: even water can be toxic if you drink too much. It seems odd because most of the time, we think of toxicity as clear-cut, a property some things have and others don’t. A widespread belief in popular culture has it the origins of a substance tell you how toxic it will be. If a compound is made by Nature, we assume it must be good for us. If it’s artificial or it has a long unpronounceable name, on the other hand, we assume it must be toxic, and it’s only a matter of time until scientists figure that out.

Alas, the truth is more complicated than popular culture would have you believe. Nature makes poisons more vicious than any chemists can invent. And nearly anything can be toxic if you consume too much.

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