permaculture

[Rain Tenaqiya <raincascadia@yahoo.com>]

I would like to know more about what kinds of biocides, pharmaceuticals, and 
other organic chemicals can be taken in by plants.  In my biology classes, I 
was taught that plant cell membranes are very selective about what they let 
inside when it comes to organic compounds.  Most testing for crop residues 
seems to focus on the outside of the plant rather than the inside.  What 
kinds of things could a plant intake that could cause problems for people?  I 
think this is an important question, not to be used as a way to justify using 
nasty chemicals on farm land, but to utilize existing wastes and soils that 
may not be perfectly "organic."
 
Many of the substances commonly used in households are relatively benign once 
introduced back into the environment (this has nothing to do with their 
manufacture, with often has much more impact).  For example, Draino is mostly 
just very alkaline salts and would cause no problems for humuns eating plants 
grown in soil contaminated with it (assuming the plants could still grow in 
that soil).  Most detergents, soaps, and cleaning break down into basic 
chemicals, some of which feed plants.  Biocides and pharmaceuticals are 
another story.  If they are long-lived (like Prozac is proving to be), then 
they could potentially be taken up by plants and eaten by people, which isn't 
a nice thought.  They might even be transformed into something worse in the 
process.
 
But in the ecotopian communities I envision, this would hopefully not be a 
problem and we could return humunure back to the soil on a large scale, 
closing the nutrient loops and creating sustainable culture.  Even now, it 
would probably be better to return sewage from cities to farms than to mine 
and/or deplete soils.  I wonder what a cost/benefit analysis would say?
 
Rain

                
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