Regulatory Update: 30/2008
Issued: 11 September 2008
This Update summarises the results from an analysis of crops, manure, and soil following damage to allotment crops believed to be caused by residues of aminopyralid in manure. Previous information can be found in Regulatory Updates 15/2008, 18/2008, and 23/2008.
Findings reported in Regulatory Update 18/2008 have confirmed that using manure that may contain residues of aminopyralid does not have implications for human health.
However, the approvals for marketing and use of aminopyralid-containing products will remain suspended while investigations into the circumstances of the phytotoxicity continue. The analysis reported below is part of that investigation.
It has been difficult to find examples of damage where details of the source of the manure and how much might have been derived from treated grassland are known with any certainty. In the first example that went some way to meeting these criteria, the manure had been supplied over a number of years by a single farmer. Dates are not precise but after purchasing in January 2008 and digging in or rotavating during February-March, various crops were planted in April. Samples of the remaining manure, treated soil, and affected potatoes and tomatoes were taken in July and analysed by the government’s The Food and Environment Research Agency.
Crop samples of potatoes and tomatoes contained trace amounts of aminopyralid. The levels were below the Limit of Quantification (LOQ) of 0.02 mg per kilogram. The LOQ is the lowest level at which quantifiable residues can be measured.
The unused manure sampled in January still had trace residues below the LOQ.
It was not possible to find aminopyralid in the treated soil taken. This reflects the bacterial decomposition that begins to act on the pesticide after free aminopyralid is released from plant material in the manure in the first few weeks after digging in.
PSD will continue to investigate this matter and hold further discussions with the main data holder, Dow. This action will help to decide whether, and if so, under what conditions the suspension of aminopyralid products can be lifted.
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