At 08:08 AM 11/25/02, you wrote:
>http://www.state.nj.us/dep/dshw/rrtp/compost/problem.htm
>
>"Some pesticides also may be present, particularly in grass clippings, but
>again the levels ordinarily are expected to be too low to pose any concern.
>An unconfirmed 1991 study in Illinois found low levels of 19 pesticides in
>composting yard wastes. The concentrations were so low that all except one
>of the 44 samples met the levels allowed in raw agricultural commodities for
>the 13 detected pesticides for which such levels have been established. (No
>levels are set for the other 6, which were mostly banned pesticides no
>longer in use.) In samples from 6 sites in New Jersey only one pesticide,
>chlordane, was detected. Since chlordane is no longer used, and since it is
>not taken up by plants,
Chlordane is taken up by plants. Cucurbits draw it into their flesh and can
actually concentrate it in their seeds to a level equal to the soil
concentration. I know that this was taken from the above website but it is
certainly in contradiction to the data I have seen here in Oregon. This can
be a real problem for pumpkin seeds, pickles, etc.
> it is believed that this came from the residential
>soil mixed with the yard waste during raking or bagging.
>
>Based on these considerations and findings, yard waste compost is considered
>safe for residential use without specific testing. The only exception to
>this would be for composts containing materials from golf courses, where
>more intensive use of more toxic and persistent compounds is common. Such
>materials may require testing for specific metals and pesticides before
>general use."
>
>A more careful approach is now warranted due to the clopyralid problem.
>(Moment of silence while we all thank Dow Chemical.)
>
>http://csanr.wsu.edu/programs/compost/cc13.pdf
>
>.....
>"Researchers F.C. Michel and C.A. Reddy at
>Michigan State University studied the fate of three
>commonly used lawn chemicals during composting:
>diazinon, 2,4-D, and pendimethalin (Prowl). A
>laboratory scale compost system was used for leaves
>and grass (in a 2:1 ratio) amended with radiolabeled
>pesticides at levels typical for incoming feedstocks at
>a commercial compost operation. Evolution of
>labeled CO2 was a primary indicator of pesticide
>breakdown.
>
>About 50% of the 2,4-D was mineralized to CO2,
>compared to only 10-13% of the other two pesticides.
>Leaching and volatile losses were low. The
>researchers then searched for the fate of the
>remaining carbon. Much of the labeled carbon from
>all three pesticides was associated with the humic
>materials or was unextractable from the final
>composts. These pesticide residuals appeared
>chemically quite different from the parent compounds
>and less available to plants and animals. Thus, while
>complete mineralization did not occur, decomposition
>appeared to eliminate the pesticides as bio-active
>materials.
>
>Researchers at the University of Guelph are studying
>the fate of 2,4-D, mecoprop and dicamba applied to
>turf and then composted. They measured a 78-87%
>loss of the herbicides over 10 weeks of composting.
>But the mass of compost declined by 92%, leading to
>an increase in the concentrations of the herbicides.
>(see http://www.uoguelph.ca/GTI/94anrep/94r9.htm)
>
>More recently, there have been several instances of
>phytotoxicity from composts produced in Washington
>State. A relatively new lawn herbicide from Dow
>Chemical called 'Confront' (clopyralid) appears to be
>causing herbicide damage on plants grown with the
>compost from the Spokane, Wash., facility. Confront
>is intended to provide residual weed control in the
>soil. The product label specifically states "Do not
>use compost containing grass clippings from turf
>treated with Confront in the growing season of
>application."
>
>The herbicide has a half-life of about 250 days. The
>60-90 day composting process at Spokane did not
>break down the material. Clopyralid was present
>only in trace amounts in the compost and in the
>plants. The limit of detection is 0.03 ppm, and levels
>were below that. Even so, enough herbicide was
>present to kill tomato plants.
>
>Recently, a two-part literature review of the fate of
>pesticides in composting was published in Compost
>Science and Utilization (Buyuksonmez et al.; Fall
>1999, Winter 2000). While the recent problem with
>Confront was not included, the authors generally
>concluded that pesticide degradation in compost is
>similar to that in soil. Compost may have different
>microbial communities, higher temperatures, and
>more active organic matter. But those pesticides that
>are persistent in soil and cause residual phytotoxicity
>may exhibit the same problems in compost and
>should be candidates for more careful monitoring
>than pesticides that routinely degrade."
>
>In a word, life is complicated, and a blanket assurance that pesticides are
>degraded by composting is not fully adequate in the Brave New World we live
>in.
>
>Like others on this list, I do collect substantial quantities of fall
>leaves, which are the backbone of my composting and vermicomposting. I rely
>on the general virtues of degradation that I know I can expect from
>composting, and I tend to stay in the higher range of C:N values, which
>favors the fungal growth which I understand is most likely to degrade
>recalcitrant materials.
>
>There may be some chlordane in my area, even though it has been banned for
>more than a decade, since it was once recommended as a lawn and garden
>insecticide. As far as I know, there is not any use of clopyralid in the
>local lawn chemical industry.
>
>It could be in food wastes, though. The Canadian government recently
>approved clopyralid residues in food materials at levels as high as 7 ppm.
>Brave New World, indeed!
>
>Frank Teuton
>
>
>----- Original Message -----
>From: "Dale Wilson" <nosliwelad_at_YAHOO.COM>
>To: <SANET-MG_at_LISTS.IFAS.UFL.EDU>
>Sent: Monday, November 25, 2002 5:56 AM
>Subject: Re: [SANET-MG] Purity Of Organic Foods
>
>
> > Dave,
> >
> > > My wife complains that when I collect the 80 or more bags of leaves
> > > from my neighbors that they may have sprayed their trees or worse yet
> > > leaves may have touched the spoiled grass, tainted by fertilizers.
> >
> > When I read this I thought of one of my favorite passages from the
> > bible "Love covers a multitude of sins." The "deep Basidiomycetic
> > penetralia of the soil" (to quote E.O. Wilson) is like love. With very
> > few exceptions, everything is broken down and recycled in the pile and
> > in soil, and pretty soon everything is "natural."
> >
> > Dale
> >
> > __________________________________________________
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Yours,
Dave DeCou
.
Received on Mon Nov 25 2002 - 15:15:56 EST