Ecology's Waste 2 Resources (W2R) Program is working to reach goals outlined in the Organics Initiative of the Beyond Waste Plan (Washington's strategy for managing hazardous and solid waste). This 30 year plan has a clear and simple objective: eliminate wastes and toxics whenever we can and use the remaining waste as resources.
According to Ecology's 2009 Washington Statewide Waste Characterization Study, organic materials (food scraps, green waste, animal manure, animal carcasses, paper products and wood debris) are 55% of our state's municipal solid waste (MSW); with the most prevalent material type being food scraps (18%). On a larger scale, the U.S. Environmental Protection Agency's Revised 2010 MSW Fact sheet, states that organic materials continue to be the largest component of MSW in the country with 29% paper, 14% food scraps and 13% yard waste. Most organic materials can be diverted from landfills and made into soil amendments, energy, or other products. W2R supports these projects by providing technical and some financial assistance (W2R Grants and Financial Assistance).
Biosolids are another type of organic material. Visit Ecology's Biosolids page for more information.
NewsHERBICIDES: If you apply herbicides to your lawn, it's important to read the label and know whether or not you can compost the treated grass clippings. Some herbicides do not break down during the composting process. If contaminated compost is used, the herbicide may still be active and could impact growth of some sensitive plants.
Persistent herbicides do not break down easily and some can remain in soil, plants, and animals for years. They are used to kill broad leaf weeds in range crops. Manure from animals that eat treated hay will have herbicide residues, and should not be composted.
Watch for aminopyralid residues in manure-based composts and soil blends (Abbreviated from the June 2010 WSU Whatcom County Extension Fact Sheet)
AminopyralidWhat is aminopyralid? It is a broadleaf herbicide registered for use on grassland (including rangeland). It is registered under several product names such as Milestone® and ForeFront® R&P. Aminopyralid is used to control many broadleaf weeds, including invasive and noxious weeds. It is used on grass crops and on non-cropland areas.
Why is it in manure-based composts? Aminopyralid was probably used to control weeds on grassland for dairy farms. The grass was cut and consumed by dairy cattle. Aminopyralid breaks down slowly or not at all in the digestive system of a cow or in the composting process, so it will show up in compost or other manure based soil amendments.
What will it do to my plants? Residues of aminopyralid in manure, composts or soils can cause damage to sensitive plants at levels as low as 1 part per billion. Some plant species are more sensitive than others, but all broadleaf plants are considered sensitive to aminopyralid. Damage includes cupped leaves, twisted stems, distorted apical growing points, and reduced fruit set.
What can I do to test for aminopyralid? Before using or distributing products that contain organic matter from a dairy, perform a bioassay. This can be done by planting seeds of plants with known susceptibility, such as peas, beans or tomatoes, in small pots with a mix of suspicious material and peat-based potting mix. For instructions for this bioassay, see WSU's Bioassay Test for Herbicide Residues in Compost.
What else is being done? Washington State University Extension is working with Washington State Department of Agriculture and other agricultural organizations to determine the best way to use remaining dairy derived organic matter containing aminopyralid residue. Residues may remain in the soil, plant tissue, and dairy waste for a year or more; the farming and gardening community need to work together to fully understand the issue and determine the best steps to manage weeds and manures.
See Washington State Department of Agriculture's Herbicides in Compost fact sheet.
Clopyralid contamination is still a risk in some manure-based compost.
Clopyralid in Compost (WSU)
Watch for new persistent herbicides.
Herbicides that are persistent in compost continue to make news. See the USCC's Persistent Herbicide FAQ page.
The herbicide Imprelis warning was initially reported in the USCC newsletter Vol 2, No. (2011). It has now been registered in every state except California and New York for use by licensed applicators on lawns and other turf areas for control of broadleaf weeds. The label clearly states that clippings from treated grass should not be used as mulch or put in a compost pile. "One problem is that the warning is on page 7 of a 9 page label," remarked Dr. Stuart Buckner, Executive Director of the USCC, "and unfortunately not everyone reads or follows the label. We are requesting the USEPA initiate a special review of the registration due to the likelihood of residual herbicide levels in compost damaging non-target plants." See the USCC's Press Release and the USCC's Composter Alert.
At this time DuPont has suspended sale of Imprelis and is conducting a product return and refund program. They are reviewing the effect of Imprelis on compost and some sensitive evergreen tree species. For current information see DuPont's Imprelis fact sheet.
Success StoriesEuropean Commission
King County Green Schools Program
Soils for Salmon Case Studies
Compost Use on State Highway Applications
WSU Whatcom County Extension
Western Washington University
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