Campaigners have revealed the results of farmland testing which provides new evidence of the potential link between intensive poultry units and the decline of the River Wye. Citizen scientists sampled farmland along public footpaths near a tributary to the river in Herefordshire. They discovered the soil with the highest levels of phosphorus, which can blight a river, were close to intensive poultry units. The results of the tests by the Wye Salmon Association with support from CPRE, the Countryside Charity, were presented to River Wye nutrient management board on 28 September. It is responsible for delivering the objectives of the special area of conservation. The Observer revealed last month how the food giant Cargill, whose chicken supply chain has been linked to the Wye’s decline, faced claims over similar pollution scandals in the US. The company denied liability in the claims. Volunteers sampled 22 sites around Garren Brook, a Wye tributary, and analysed them using an Olsen P test a standard test for phosphorus in soil. The four sites with the highest levels were all close to large poultry farms. Gordon Green, the report author and a member of the Wye Salmon Association, said: “We need an annual survey of the entire catchment. It’s a mystery why this isn’t done routinely already.” The Herefordshire poultry industry has expanded rapidly since the 1990s. Activists say phosphates from poultry litter are washed into the Wye, fuelling the growth of algae blooms which can suffocate a river. Last year a Lancaster University study found chicken litter was the main source of farm manure causing Wye phosphate pollution. The new report provides further evidence of a potential link between chicken farms and pollution on the river. The government’s code of good agricultural practice says farmers should avoid spreading manure which raises soil phosphorus above target levels. Campaigners are calling for stronger regulation. Tom Tibbits of Friends of the Upper Wye said the current system was ineffective. He said: “They’ve got tonnes of chicken manure to get rid of and have got to find somewhere to put it.” An Environment Agency spokesperson said: “The River Wye is an iconic river. We have secured additional funding to increase monitoring activity on the Wye. Solutions will take time and require maximum effort from partners, river users, farmers and businesses.”