Thalocean2 wrote:

Yes, it is a problem with human waste as well. That's why the human waste that
is spread all over farms in many states is first spun to remove the heavy
metals. It's a natural part of humans, dogs, cats etc. waste and when it's
concetrated to one small area, (your garden) the heavy metals can and do build
up to toxic levels. Do a quick search and look at all the court case documents
where farmers are sueing because their fields are ruined...



I assume that by human waste, you mean sewage sludge, since the
collection of human waste is basically only done at sewage treatment
plants (except for a very few outback places that still use privies).
The occurrence of heavy metals from sewage sludge is not necessarily
related to heavy metals in human waste. The heavy metals in the sewage
comes from people's practice of dumping everything down the drain in
addition to human waste.

Moreover, the availability of animal waste in large quantities (thank
you McDonalds and Col. Sanders) would render the collection of human
waste not economically feasible on a large scale outside of the sewage
treatment plants.

I have never heard of anyone spinning human waste before applying it to
fields, and I don't believe that spinning or centrifuging sewage sludge
containing heavy metals would separate them out. This process would be
extremely expensive and time consuming since the sludge would have to be
liquefied so that the heavier particles would be mobile enough in the
soup that they could settle out. The centrifuging equipment would be
costly and the same result could be obtained by letting the liquid
settle for an extended period of time. I am open to any references you
might be able to supply for this practice.