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  • From: "Lawrence F. London, Jr." <venaurafarm@bellsouth.net>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: Re: [permaculture] [Fwd: [SANET-MG] Convert landfills to compost!]
  • Date: Wed, 23 Dec 2009 00:14:17 -0500

Armed With A Mind Armed With A Mind wrote:
> One factor to consider with municipal scale composting systems is the contamination. In the city of Toronto they apparently used to have a composting system, and residents were free to come pick up finished product for free. The compost was tested and was found to be contaminated and unsafe for use in food gardens. I'm not saying that this should stop such programs but it is something that most do not think about and some extra step should be put in place to remove the contaminants if testing shows it to be present.

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If they are recycling yard and landscape waste there is always the risk of contamination from various categories of pesticides, particulary herbicides and especially roundup and the less biodegradable products
like chlorpyralid.
http://newfarm.rodaleinstitute.org/depts/talking_shop/1203/watilth3.shtml
Compost. The chlorpyralid herbicide problem has receded since restrictions on chlorpyralid use were put in place. The problem has been that plant materials that have been in contact with chlorpyralid and still have the residues on them, pass through the composting process and kill plants that come into contact with the compost. There have been no reports of chlorpyralid contaminated composts for two years, so testing of composts for chlorpyralid is no longer mandatory in the state of
Washington.

Chemical spills, spills of all categrories of pesticides used by homeowners or landscape contractors, dirt, mulches, potting soils, etc that might have had these substances applied to them or spilled on them that might have gotten mixed with the yard and landscape waste, all possibilities of these scenarios apply when assessing the safety of recycling yard waste for use by people as an amendment to their food producing gardens. There are two categories of recyclable biomass available from municipal waste collection and processing centers,
1) ground, shredded, pulverized landscape waste, usually larger woodier items including stump, tree trunk, branch and twig grindings, root systems, the heavier items
2) bark and light woody material, prunings, weeds of all sorts, vines, grass clippings and leaves; sometimes the leaves are stored and recycled by themselves
2) is where the problem lies as that group of landscape waste items is most likely to be contaminated to a greater or lesser degree
The professional lawn and yard, business and industry landscape maintenance companies are likely users of chemicals for many of their maintenance tasks, especially herbicides such as roundup, 24d, atrazine,
chlorpyralid but also fungicides and insecticides. All this can end up in the yard or landscape waste. Contaminated dirt, mulch and potting soil can also get mixed in.
From what I know grass clippings are the most likely source of contamination, possibly long term, of municipal compost destined for use in food producing gardens or production of food crop seedlings or as mulch.

Here's more from the New Farm magazine:

http://newfarm.rodaleinstitute.org/depts/talking_shop/1203/watilth3.shtml
<...>
NOSB snubbed. Author’s note: Several materials recommended by the National Organic Standards Board (NOSB), an advisory board to the NOP, were not approved. An ongoing issue throughout the evolution of the NOP Final Rule has been the NOP refusal to fully implement the recommendations of the NOSB. The NOSB is made up of volunteer members from the organic farming, support, and consumer sector, while the NOP is part of USDA and, in the end, does what the USDA bids.

The NOP zero tolerance problem. Another issue that McEvoy raised is that the NOP is going with a zero tolerance policy on what the WSDA-OFP has considered to be minor non-compliance issues having to do with the use of inert ingredients in various products.

Clarifications of the rules

Treated wood. Wood treated with chromium arsenate can’t be used as new or replacement items that come into direct contact with certified organic soil, plants, or animals. The issue of “direct contact” was discussed. A fence in a pasture is considered not to be in direct contact, since it is a border. A farrowing pen, a trellis, or a raised bed structure is considered to be in direct contact.
<...>
Compost. The chlorpyralid herbicide problem has receded since restrictions on chlorpyralid use were put in place. The problem has been that plant materials that have been in contact with chlorpyralid and still have the residues on them, pass through the composting process and kill plants that come into contact with the compost. There have been no reports of chlorpyralid contaminated composts for two years, so testing of composts for chlorpyralid is no longer mandatory in the state of Washington.




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