The Yorkshire Post carried a follow-up to their report on our problems with herbicide contamination this week. To read the article click here
The publicity given to this problem is obviously alerting people to the problem as we have had a couple of visits from nearby allotment holders and gardeners asking for more detail.
6 months ago
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I have had veges tested in a laboratory for residue of aminopyralid and nothing has shown up, not because it is free of contamination but because there is no effective test yet that can detect the herbicide.
ReplyDeleteDOW are working on a test with the lab.
That is absolutely spot-on Anon, the same is true for testing of soil or compost.
ReplyDeleteThe RHS say:
The issue of testing is flawed. Even cases of known contamination have failed to be confirmed by laboratory testing simply because the residue levels are too low to be detected.
All testing can do is prove aminpyralid is there not the opposite. Also fromour experiences the amount needed in the soil to affect plants is far less than that needed to control weeds. We have weeds growing happily where plants are failing!
Who tested your veg and how much did it cost you?
To RHS
ReplyDeleteIt was not necessarily because the residue is too low to recover, the lab and DOW are unable to recover aminopyralid from plant material because it sticks too strongly. Ask DOW.
Yes sorry - the response from the RHS was about the difficulty of testing soil and being able to confirm that it was free of contamination - it could only at best confirm contamination was present - which in itself is difficult in this instance - I just really meant to show that testing in all scenarios is extremely difficult.
ReplyDeleteSorry but this is nonsense. It may be that the lab consulted cannot detect levels but the Canadian equivalent of our PSD has measured levels in flour from sprayed cereals, bread made from the flour, eggs from chickens fed with corn from sprayed wheat, meat from animals fed on treated hay. All the results are available on the web. The levels may be low but they are measureable. Whether you think they are acceptable is a different matter.
ReplyDeleteThe information that the testing of plant material and soil is inconclusive comes from the PSD, DOW and the RHS.
ReplyDeleteThe amount of residue necessary in these substances needed to cause damage to crops is so small that a negative result doesn't mean that the chemical is not present.
Not being a scientist I can only go by what the experts tell us which is that a positive test proves aminopyralid is present but a negative one doesn't prove that it isn't.
I guess the testing is different on crops etc where they know spraying has occurred and when the spraying occurred. Also I guess to prove something is safe they are looking for maximum levels of residue in test results so it isn't inconceivable that some tests could come up inconclusive.