Anyone else concerned about the carcinogens created because of incomplete burning when making bone sauce? This article says the PAH can last for months in the ground and breathing the stuff isn't good either. I plant a lot of food around my trees. If the trees were in a orchard or field, the bone sauce would be great, close to other edibles, I'm not so sure. Any ideas? https://www.atsdr.cdc.gov/phs/phs.asp?id=120&tid=25
That's an interesting point. I think it boils down to concentrations. If your bone sauce washes off in the rain, settles on some veggies you are about to harvest, and you eat them, sure, I would expect you to eat a bit of bone sauce. Yuck.
But if you apply your bone sauce and it stays pretty much on the tree, with a little flaking off into your soil now and then, I wouldn't worry. If you have healthy soil, the fragments of bone sauce will likely be eaten by microbes or soil macrobiota. I would be surprised if there remained any identifiable levels of carcinogens in the soil.
I think it's also a matter of perspective. If you eat anything cooked in a way that produces a Maillard reaction, that nice browning effect that we observe with meat and vegetables both, you are creating carcinogens through incomplete combustion. If you live in a city, or in an urban exhaust plume, your air contains higher amounts of carcinogens. If you smell woodsmoke, chances are...
You see where I'm going with this. I don't think there's any real cause for special concern about the carcinogens in bone sauce. If you're worried about carcinogens, there are bigger fish to fry (or steam, fewer carcinogens).
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein
Sunlight is a carcinogen.
Everyday every living thing is bombarded with countless exposures to DNA altering chemicals and radiation. It's unavoidable, weather you're in a dense industrial city, or hundreds of miles from the nearest paved road. Fortunately, evolution produced a bunch of ways to repair DNA and and reverse that constant damage, not to mention a healthy immune system helps keep things in check. Any living body (accidentally) produces cancerous cells on a somewhat regular basis but healthy habits prevent that from becoming a problem.
When it comes down to carcinogen exposure through permaculture, just take a step back and look at the alternatives.
With all of that being said, any charred carbon rich material will contain elevated levels of mutagenic DNA altering organic substances, don't rub the bone sauce directly on your skin or on the fruit and you should be fine.
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