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Posted by David Sherman [72.47.9.228] on Tuesday, December 28, 2010 at 18:07:19 :
In Reply to: Here here! posted by Ed Tavernier [24.188.91.191] on Tuesday, December 28, 2010 at 17:45:48 :
I agree with most of that, but the last part isn't quite true. While there might be parts per trillion of some chlorinated hydrocarbons, for example, that are formed naturally in the reaction between tropical sunlight, salt water, and dead fish, the amounts are minuscule compared to what was found in, say, a 55 gallon drum of agent orange or even a bottle of weed-b-gone. There are also lots of chemicals, both harmless and harmful, that are never found in nature either because they're too reactive (metallic sodium and magnesium, for example), or they can only be made via tricky processes that start with highly reactive substances (fluorine to make Teflon, for example, or phosphorus to make Roundup). There are also radioactive elements such as plutonium that are only made in high-powered nuclear chain reactions of the sort that require conditions that are never found in nature. So, if we assume we're only talking about chemicals that exist in a large enough quantity to actually detect and be exposed to, then there are indeed a lot of man-made ones that were never found in nature.
The flip side of that is most of the seriously deadly poisons are not simple inorganic compounds like lead and mercury salts but are complicated organic molecules synthesized by living organisms in order to poison their enemies and competitors. That includes botulin toxin, amanita phaloides toxin (amatin), ricin, strychnine, various snake and spider venoms. Nature has been refining them for millions of years and some of them are really amazing in their effects. They are 100% organic, 100% natural, and vastly deadlier than anything you'll ever find in a store with warning labels and a skull and crossbones on it. No, they don't cause cancer, but it isn't because they're natural and organic. It's because they kill you way too fast. There are plenty of natural carcinogenic chemicals as well. Bracken fern fiddleheads are one that I'm familiar with that some people do eat. Euel Gibbons died of stomach cancer.
As for acetone, the main reason it's become more popular than petroleum solvents is that it's exempt from California VOC regulations. Although it's volatile and it's an organic compound, it doesn't contribute to smog like petroleum solvents do, so it's allowed as a solvent in paints and adhesives. The fact that it doesn't cause smog has nothing to do with it being particularly non-toxic to humans.
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