In TOS no. 108 (April 2010) it was reported that in the US the Californian Department of Food and Agriculture (CDFA) had banned three green waste composts from use in organic production after traces of the pesticide bifenthrin had been found.

The bifenthrin contamination was discovered under unusual circumstances that illustrate some loopholes in the regulatory framework for organic compost. In this case, the pesticide was discovered when a wheatgrass farmer in Placerville had his product tested by the California Department of Pesticide Regulation. ‘The wheatgrass farmer figured out that wheatgrass grew really well in straight compost. The wheatgrass was shipped to the grocery store in a tray full of soil’. Because it was sold in that manner, explained Adam Grover, one of the three affected compost suppliers, the testers threw both the wheatgrass and some of the attached soil into the blender for testing in the lab. ‘When they tested just the wheatgrass, it was free of bifenthrin, but when it was mixed with the compost, it was not.’

The US National Organic Program (NOP) initiated a policy formulation through consultations with the accredited certification bodies, and a meeting was held in January 2010. Meanwhile, California Certified Organic Farmers (CCOF) tested soil and crop samples from fields where contaminated composts had been applied in July 2009. No bifenthrin residues were detected, at a limit of detection of 0.01 ppm.

On 19 April, 2010 the NOP released a directive entitled ‘The Allowance of Green Waste in Organic Production Systems’. This directive clarified that NOP regulations were developed with the understanding that there are background levels of synthetic pesticides and that they may end up in organic products, so-called unavoidable residual environmental contamination. In addition, it made it clear that NOP standards are process-based and has no stated zero-tolerance for inputs such as compost. However, the standards also say that the producer should handle materials in a manner that they do not contribute to the contamination of crops, soils and water. These two considerations have to be balanced, prompting the directive to conclude that ‘Green waste and green waste compost that is produced from approved feedstocks, such as, non-organic crop residues or lawn clippings may contain pesticide residues. Provided that the green waste and green waste compost (i) is not subject to any direct application or use of prohibited substances (i.e. synthetic pesticides) during the composting process, and (ii) that any residual pesticide levels do not contribute to the contamination of crops, soil or water, the compost is acceptable for use in organic production.’

As a result, the CDFA released an announcement on 21 April, 2010 stating that the prohibition of the three above named composts has been rescinded. The Organic Materials Review Institute (OMRI) welcomes the NOP clarification and feels that resolution of this issue will aid OMRI, certifiers and growers in verifying compliance of input materials for organic farms.

Gunnar Rundgren

Sources: (the NOP statement)