This site is undergoing reconstruction so some links may be broken
Places to Visit
School Veg Patch
Following this year's problems with pesticide residue in manure, DOW AgroSciences have created a website - Manure Matters - to provide guidance and advice.
As usual my words are in green
Contact with MEP
Question asked of MEP : Linda McAvan
I emailed you earlier in the year about our problems with contaminated manure. Just wondered if you had any idea whether the new EU legislation on pesticide use would affect the use of aminopyralid the herbicide that caused our problems. From what I can find out it would seem not as aminopyralid is supposedly not harmful to humans.
From what I have read I can't understand why farmers are so upset about it as the legislation seems only to apply to chemicals that have proven health affecting issues. It just seems strange that to ban a substance it has to be proven to be harmful as if this is the case how did these chemicals receive approval in the first place. Surely on initial application they would have to have been proven to be safe wouldn't they?
24 February 2009
Thank you for your e-mail regarding the new pesticides legislation which has recently been adopted by the European Parliament and national ministers and whether it could help with your problem of contaminated manure.
These new laws strengthen the existing rules for governing the production, licensing and use of pesticides. One such measure is a new authorisation procedure for plant protection products. This would cover all products containing active substances, safeners or synergists intended for use as a plant protection product. To be authorised, the product must meet a strict set of criteria, including that it shall not have any unacceptable effects on food or plants. It is therefore not limited to health effects. I have attached a copy of the new law, which lists the criteria in Annex II so you can assess whether the authorisation of aminopyralid would be affected.
However, this legislation will only gradually supersede existing EU law. Pesticides that can be placed on the market under current legislation will remain available until their existing authorisation expires. Once the license for aminopyralid runs out, the producers would have to submit a comprehensive dossier with test results showing that it met the strict criteria outlined in the Regulation. There is also the possibility for the public to submit opinions and evidence.
I hope this information is helpful and the new rules are useful for your case.
Conversation with DOW Agro-Chemicals
I have just had a very long telephone conversation with a DOW representative who was very helpful, so just to pass on some information obtained.
First of all we need to all be aware that DOW produce aminopyralid which is only one of the herbicides that may potentially be affecting our manure supplies. Dow's name has been given as a source of information to the public as they are the only company of this type with a public helpline and they are happy to field calls or email enquiries. This could mask the fact that the chemicals responsible for our problems may be from different companies and have names other than aminopyralid. As well as herbicides used on grass, chemicals used on wood shavings (typically used for horse bedding) may also have the same affect on our plants. These could be industrial chemicals as well as herbicide related.
Symptoms in plants:
Plants being poisoned by herbicide residue will typically exhibit the spoon shaped leaf growth. If this symptom is not present then it is likely that the problem to plant growth is attributable to another cause.
From tests done on cows ingesting treated silage or grass it has been shown that only a very small quantity of any residue is digested. 98% of the residue passes straight through the cow. As human digestive systems are even less efficient in the digestion of plant material this should be less for us. I am told that there are not carcogenic substances in the herbicide. If manure products are at all suspected of causing tummy upsets it is more likely that these are caused by bacteria present rather than chemicals
Texture of manure
The herbicide does not alter the texture of manure. Any sliminess or strange textures are maybe attributable to how manure has been left stacked. It is possible that manure with this type of look and feel has been stored at the bottom of a pile for a time and that rain etc has washed through the soil causing it to sour. This means that there is less air in the manure and decomposition will be much slower. Residue may also seep down the pile causing a more concentrated build up in this area. It is possible that even if gardeners have bought manure from the same pile that some will suffer worse effects than others due to where their particular manure was within the pile being stored on the farm. This is backed up by our experiences as the areas where we stored manure prior to spreading is the worse affected area. Our manure was stacked for about three months during which time we experienced heavy rain. Other plot holders have had worse symptoms in areas where the manure was stacked too.
Composting of affected plant materials
Affected plant material should not be composted on the compost heap as it is bacteria present in soil that breaks downs the chemicals. Affected crops should be dug back in to the soil. Burning was mentioned earlier but RHS don't recommend this method of disposal. See RHS response below.
Manure too fresh?
The use of manure that is too fresh will not produce the distorted leaf symptoms shown in the case of herbicide damage where the leaves curl upwards like a spoon. Fresh manure affects the roots of plants by burning them and not the top growth. Potatoes may have scabs on their tubers. Plants may also display symptoms of black leg.
Can residue leach into surrounding areas?
I have checked with the chemical company about the likelihood of residue seeping onto neighbouring plots and they say that once the manure has been mixed into the soil, any leachate is more likely to go into the soil profile rather than sideways. If there is any sideways movement it will be feet rather than yards, and this would only happen with manure on the surface, and torrents of rain.
We have areas on our plot where two plants growing right next to us have one showing damage and the other not - which seems to confirm DOWs answer - that is not yet! Although run-off seems to be another matter whereby particles have been swept downhill of affected areas and caused a problem.
Dow's Notice to Allotment Holders and Gardeners
Dow have published a web page of frequently asked questions with respect to the current problem This is no longer available
Frequently Asked Questions:
June - October 2008
Question: If veg is growing in land that has been manured using contaminated manure but shows no signs of being affected – is that safe?
Well there is no way you can exclude the possibility of weedkiller being present. Although the weedkiller is not considered a toxic material and must be present in vanishingly small quantities if plants are not affected there is no data on how safe the produce is to consume. One might assume the risk to be small but without solid scientific data it would be folly to assert this with confidence
The residue levels will decline in time, though this process is slower in plant tissue than in the soil. Delaying harvesting from affected plants until 2009 is a sensible precaution. For annual crops such as potato, it is best not to recommend consumption.
The PSD say that they are going to obtain samples to test. I wonder if given the nature of how the herbicide residue is released whether this would be in any way conclusive.
PS Date update:
Following PSD update the advice now is that it should be safe to eat vegetables growing in the soil where the manure has been used.
Question: So should we have our soil tested?
The 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
Question: Apparently courgettes and squash don’t succumb and appear to thrive so are they safe?
Quite possibly but no one really knows for absolute certain. Because the weedkiller is not considered a toxic material and must be present in vanishingly small quantities where seems little reason to be overly concerned if you have already consumed produce, although clearly if people feel ill they should consult their physician.
PS Date update:
Following PSD update the advice now is that it should be safe to eat vegetables growing in the soil where the manure has been used.
Question: If affected plant material is burned then is the ash safe to use on crops?
This is not a recommended way of disposing of contaminated plants. The recommended way is to incorporate plant material into the soil so soil microbes can degrade it. The sooner this is done the longer the microbes have to do the job when the soil is warm and moist.
Question: So should we be asking for compensation?
John from Sandwell has been advised by his National Society of Allotments and Leisure Gardeners representative that a reasonable compensation calculation is 2 years rent + the value at supermarket organic prices of two years produce + 50%
(Has anyone else had advice on this and who a claim should be made against).
Question: Is anything happening out there officially about this problem?
The manufacturers are very, very disappointed that things have come to this and are putting all their efforts into making sure it does not happen again. We are going to help them. I would point out that the manufacturers have handled this is a very open, honest and straightforward way and had their instructions on using the weedkiller been followed none of this would have happened.
It would seem that there is a need to raise the standards in the hay, silage and manure trading chain and the manufacturers are going to educate farmers, farm advisors and hay merchants. Since this response see PSD update
Question: Could straw used as a strawberry mulch for instance be contaminated?
Aminopyralid does not currently have approval for use on cereals so is unlikely to find its way into straw used for bedding or under strawberries.
Question: How can we be sure that green waste from our local council is ‘clean’ – can this herbicide be used by parks departments? It seems to me that the only sure way to be certain is to use one’s own compost.
There is one product containing aminopyralid approved for use on amenity grassland but it is not clear how widely this is used. I suspect the number of cases of composted green waste from local councils being contaminated with weedkiller is very small, especially in comparison to manures. You are right that some risk does exists from external sources of organic matter but I feel the benefit of using recycled green waste such as this outweighs the risks. The PSD are going to raise awareness among local authorities to be vigilant of potential green waste contaminants.
Question: If I can't use manure to improve my soil then what can I use?
Don’t stop using mulch. Organic mulches are essential to improving soil structure and soil moisture. If a reliable source of manure is not available, try using an alternative source of organic matter such as garden compost, leafmould, composted bark or composted green waste from your local council. Although it is possible that composted green waste may sometimes be made from raw materials that contain weedkiller, lawn mowings for example, we have not found this to be a problem. With increasing awareness of the risks associated with weedkiller residues in manure and composted green waste, this problem with hopefully decrease in the future.
RHS web site - Weedkiller Damage no longer available
Has information on symptoms
Use of indicator plants are frequently mentioned and so I asked a few questions about the use of these plants of the RHS:
June - October 2008:
Questions: It is suggested that particularly sensitive indicator plants are planted to test if contamination is still in the soil - how does this work?
Well, if you grow a tomato for example and it is distorted then weedkiller is probably present but if it does not, then the weedkiller might be absent, present at very, very low levels or still attached to hay, silage or straw.
Must admit I am not at all sure how the indicator plant idea will work as if the herbicide residue is only released when the plant material breaks down then the residue could be being released at any time couldn't it?
Exactly, but manure is almost entirely broken down in the first summer after application, hence by next spring it should have been eliminated from the soil by soil microbes.
I am told that after breaking down the residue takes 4 weeks to dissipate so wouldn’t it depend when the indicator plant was planted and in which area of soil as in our experience the symptoms are not consistent?
You’re a quite right everything depends on good sampling technique and there are no clear protocols for this and rate of breakdown depends on soil moisture, soil temperature, what microbes are present, how big the lumps of dung are and so on and on, leading to problems of interpretation.
Also if the RHS are saying that it would be wise not to eat crops from contaminated soil even if they show no signs of damage what is the advantage of an indicator crop?
If an indicator crop shows no symptoms it must mean that the weedkiller, if present at all, must be at very low concentrations and gardeners may decide to consume their produce, although obviously it is not possible to say that such produce is completely free of weedkiller
Could you explain how we could use an indicator plant to tell us when we would be OK to plant or indeed crop again?
Well, if you take pots of soil next February and plant tomato seedlings in them, and if you do the same with ordinary unmanured soil, and if the treated soil is as free of symptoms as the untreated soil then it should be safe to replant. But if you are looking for simple assurances of no weedkiller at all, then I am afraid it is not possible to give those assurances. You have use a smattering of common sense
I am told soya beans are susceptible too and would make a good indicator anything else that grows quickly?
Tomatoes – take sideshoots as cuttings now or raise seedlings at other times.
Input from the USA
Bob from Iowa State University says
I received a call from a person in Maryland reporting problems with tomatoes and potatoes. In terms of enough research being conducted on these products - I guess in this situation I feel we have an excellent understanding of their behaviour in the environment due to over 50 years of experience with growth regulator herbicides. Similar problems have been fairly common with products containing picloram (Tordon, Grazon) and clopyralid (Confront, Stinger).
The labels of the products specify clearly that the residues are persistent in the foliage and can be distributed in hay and manure. I think a couple factors lead to the problems:
Learning from previous mistakes?
John from Sandwell Allotments Council sent me the following link.
U.S. Composting Council position paper on Clopyralid and composting. Click here to read the full report.
The report is dated August 24 2001 and describes a similar situation to that being experienced by us at the moment. I quote:
"Recent incidents have revealed that the composting industry is vulnerable to contamination from a long-lasting herbicide called clopyralid. In several well-documented cases, compost products from clopyralid-containing feedstocks (including grass clippings, animal bedding, and manures) have damaged non-target crops due to the presence of clopyralid"
The report points to inadequate labelling but goes on to say that the problem doesn't "begin with nor does it end with the label". It further states that:
"Even if clopyralid applicators are provided with an unambiguous, accurate label, there would still be a long chain of communication that must be maintained among applicators, land owners, harvesters of the plant residuals, haulers and the compost facility operators. How will the applicators know how and where the plant residuals will be handled? How will the land owner know what chemical was applied and how the clippings should be managed? How will the compost facility operator know the history of the residuals delivered in the hauler's truck? As a practical matter, it would be impossible to ensure this essential chain of communication, rendering any improvements to the label ineffectual. A solution to the clopyralid-compost issues must provide for effective and continuous communications among all of the parties involved. If such communication cannot be ensured, the USCC strongly questions the appropriateness of continued uncontrolled use of clopyralid".
This is just what we have been saying with respect to our current problem. The actions recommended are too long to repeat here but the report is very readable so click on the link and read it for yourself.
This isn’t a complete list of media coverage as I have removed (December 2011) those links that are no longer available and no doubt there are lots of articles out there that I have not been made aware of. The same applies to the links below.
Forums and Web sites with threads on the subject and Websites
The more forums we can get talking about the subject the better so we can make sure other gardeners are less likely to have the problems that we have had in the future. If you find any more let me have the links just so we know how we are doing at getting the word out. The intention isn't to take part in all the discussions or even read them but just to get people talking about the problem - raising the profile.
MP’s getting involved
Paul Burstow MP - Member for Sutton and Cheam asked Parliamentary questions Hansard - more tabled
Linda McAvan MEP for Yorkshire and Humberside and has worked with REACH REACH is a new European Community Regulation on chemicals and their safe use (EC 1907/2006). It deals with the Registration, Evaluation, Authorisation and Restriction of Chemical substances. The new law entered into force on 1 June 2007.
Tim Brough MP - Member for East Worthing and Shoreham has asked Parliamentary questions Hansard
Nigel Farage MEP for South East
Vince Cable MP - Member of Parliament for Twickenham
Tom Watson MP - Member of Parliament for West Bromwich
The MPs mentioned above have been proactive rather than just sending a letter to a minister and forwarding the reply to their constituent. Thanks to them.
Extra reading for those interested:
any of these links point to problems in other countries well before aminopyralid was used in the UK. Some point to problems with clopyralid a similar herbicide.
Thanks to John from Sandwell for pointing me to the following link:
Snippets from above EEC Directive
● Member States shall prescribe that plant protection products must be used properly
● Member States shall ensure that a plant protection product is not authorized unless:
i(ii) it has no unacceptable effect on plants or plant products;
iv it has no harmful effect on human or animal health, directly or indirectly
(e.g. through drinking water, food or feed) or on groundwater;
Obviously the snippets above are out of context but are just intended to show that it is the government's responsibility to ensure plant protection products are properly used.
Aminopyralid Milestone review Toxicology dealt with from page 22
Clopyralid by Dow AgroSciences Found in Composted Grass
EMILY GREEN / LA Times dated 27 December 2001
University of Minnesota - advice when disposing of ditch hay (manure)
Re: Withdrawal of Milestone Herbicide Application (EPA Reg. No. 62719-519) Containing the Active Ingredient Aminopyralid. Chemical Code: 005209 click here
Evaluation of the new active AMINOPYRALID in the product Hotshot Herbicide - Australian Pesticides and Veterinary Medicines Authority, February 2006, Canberra, Australia No longer available
Aminopyralid Contamination in Farmyard Manure Soil and Land Consultants dated 11 July 2007
Persistent herbicides in compost From BioCycle Journal of Composting & Organics Recycling dated July 2001 no longer available
Tilth Producers quarterly - Clopyralid: The Story of a "Benign Herbicide" dated Spring 2003 no longer available
Position Paper of the US Composting Council
Environmental Policy and Regulatory Affairs Committee
(August 24, 2001) click here
Compost Communicator - The quarterly newsletter of the United States Composting Council
Clopyralid in Compost - Washington State Department updated 2004 no longer available accompanying factsheet dated 2002 (Links no longer available)
Aminopyralid - Dietary Exposure Assessment - United States Environmental Protection Agency - dated 21 June 2005
US Environmental Protection Agency dated 5 October 2005
Environmental Fate & Ecological Risk Assessment for the Registration of Aminopyralid
US Officer of Prevention, Pesticides Environmental Protection and Toxic Substance Agency (7501C) dated 10 August 2005
Pesticide Fact Sheet - Aminopyralid
Many of the original links are no longer available but I have left the references.
The lists above show the publicity that was acheved but still many gardeners are unaware unless they have been affected directly'