A slight increase in the number of UK water samples exceeding the 0.1 microgram a litre threshold for farm chemicals has been blamed on the very wet autumn of 2004.
According to figures from the Environment Agency, which were reported in the Pesticides Forum report on pesticide indicators, there was an overall failure rate of eight per cent, although after excluding sample failures caused by the amenity weed killer diuron, the number of samples exceeding the threshold stood at 6.62 per cent in 2005, compared with a low 5.2 per cent in 2004.
Patrick Goldsworthy, manager of the Voluntary Initiative (VI), a programme of measures agreed by the government to minimise the environmental impact of pesticides, said that high rainfall in the autumn of 2004 was the most likely explanation for the increase. A change in the number of sampling sites has also been cited.
Goldsworthy said: “What seems to have happened is that the very wet weather of autumn 2004 delayed pesticide applications until late in the year, so that the impact was not picked up until samples were taken in 2005. That had the effect of deflating both the 2004 results, and inflating the 2005 ones.
“The biggest increase was in failures caused by the amenity herbicide durion, which is used by local authorities in the spring to kill weeds on paved areas and hard-standings and is therefore particularly at risk of being washed off into drains.
“There is absolutely no suggestion that farmers have become less careful or less responsible in the way they apple pesticides. Given the vagaries of our weather, it is inevitable that there will be fluctuations from year to year. The really important thing is the long-term trend, and this is still downward, despite this setback.”
The VI pilot project shows that significant improvements can be made by farmers, by working with agronomists and water companies. Goldsworthy said: “In some catchments, 98 per cent of reductions were achieved in the number of days where exceedances occurred. This work is continuing, so as to consolidate on what has been achieved and make improvements in other catchments.”
No comments yet