(Beyond Pesticides, July 2, 2008) Gardeners in the United Kingdom (UK) have been warned not to eat home-grown vegetables that have been exposed to the new and persistent herbicide, aminopyralid. Domestic gardens and allotments have been contaminated by manure originating from farms where the herbicide aminopyralid was sprayed on fields.
All across the UK harvests of withered and rotten potatoes, beans, peas, carrots, salad vegetables and deformed tomatoes have been reported by confused and angry gardeners. It is believed that contamination of manure arose after grass was treated with aminopyralid 12 months ago. Experts say the grass was probably made into silage, and then fed to cattle during the winter months. The herbicide remained present in the silage, passed through the animal and into manure that was later sold.
Aminopyralid is gaining popularity with farmers, who spray it on grassland to control weeds such as docks, thistles and nettles without affecting the grass around them. Dow AgroSciences, which manufactures aminopyralid, has made a statement on their website saying: ‘As a general rule, we suggest damaged produce (however this is caused) should not be consumed.’ Those who have already used contaminated manure are advised not to replant on the affected soil for at least a year. Aminopyralid, however, is not licensed to be used on food crops and carries a label warning farmers using it not to sell manure that might contain residue to gardeners. Problems with aminopyralid are not new. Damage to potato crops emerged last year and at that time Dow launched a campaign within the agriculture industry to reassure farmers and to ensure that they were aware of how the products should be used. Since the chemical has now entered the food chain, many are demanding an investigation and a ban of the product. Affected farmers and gardeners say they have been given no definitive answer as to whether other produce on their gardens and allotments is safe to eat.
Unfortunately it is extremely difficult to trace the exact origins of each contaminated batch of manure and thus, claims by farmers seeking financial compensation will be difficult to prove. “I am absolutely incensed at what has happened and find it scandalous that a weed killer sprayed more than one year ago, that has passed through an animal’s gut, was kicked around on a stable floor, stored in a muck heap in a field, then on an allotment site and was finally dug into or mulched on to beds last winter is still killing “sensitive” crops and will continue to do so for the next year,” said gardener Shirley Murray of Hampton, south-west London. Dow insists that trace levels of aminopyralid that are likely to be in these crops are of such low levels that they are unlikely to cause a problem to human health. The Royal Horticultural Society (RHS) has advised, however, that vegetables grown with contaminated manure should not be eaten because the safety of the chemical is in question. Dow is already planning a major publicity campaign to reiterate warnings to farmers over usage, and to encourage gardeners and allotment holders to check the provenance of manure that they put down in an effort to prevent the problem escalating. On compensation, Dow was less forthcoming.
Aminopyralid was given a conditional registration as a “reduced risk herbicide” by the U.S. Environmental Protection Agency (EPA) in 2005 and is marketed under the trade name Milestoneâ„¢. It is used on rangeland, permanent grass pastures, non-cropland areas, and grazed areas as well as on wheat. EPA’s factsheet concludes, “[T]here is reasonable certainty that no harm will come from aggregate exposure to aminopyralid residues.” The agency has also determined aminopyralid to be practically non-toxic to non-target animals and is less likely to impact both terrestrial and aquatic plants. Aminopyralid persists in soil and half-lives range from 31.5 to 533.2 days. Label precautions for Milestone state that aminopyralid treated plant residues or manure from animals that have grazed on treated forage (within the previous 3 days) should not be used in compost or mulch to be used on susceptible broadleaf plants.
Manure contamination is not new to the U.S. Residential turf uses of the herbicide clopyralid were discontinued after reports from several states identified that the herbicide had contaminated composts. The herbicide, which does not break down during the composting process, was found in compost made from recycled grass, straw, and manure. (See Daily News: 12/14/01 and 7/31/07). Clopyraild is also manufactured by Dow AgroSciences.
Source: The Guardian UK