24 November 1995

Water controls set to tighten

By Andrew Blake

NO-GO areas for sprayers seem set to become a more prominent feature of UK arable farming.

That was the underlying message from the joint FWAG/NRA conference, Pesticide Application – Safeguarding the Environment, held in Cambridge.

Buffer zones to protect water courses from pesticide pollution are attracting growing attention. But workshops suggest there are many hurdles before a universal scheme for the full range of chemicals used on farms is up and running.

Illegal to spray too close

Already several pesticides may not legally be sprayed within 6m (20ft) of surface waters and ditches. But as the all-embracing European Directive 91/414/EEC on the approval of pesticides begins to bite, the picture is likely to become much more complex, delegates heard.

Terry Tooby, deputy director of the UKs Pesticide Safety Directorate pointed out that under the directive, risks to water sources and the environment take priority over improving plant protection. He said pesticide application is still an "imprecise" operation, often giving rise to drift. So industry has a "collective responsibility" to ensure products are used correctly.

Mr Tooby highlighted the need for "risk management" and predicted a growing emphasis on advice such as the recent IPU stewardship scheme. And he warned that unless users achieve the desired reduction in levels of IPU reaching surface waters, he will come under strong pressure to withdraw approval altogether.

Growers have two distinct responsibilities, according to Alan Barnden, pesticide adviser for the NRAs Anglian Region. One involves helping to keep the level of pesticides in drinking water below the ECs "surrogate zero" level of 0.1ppb.

The other, for which there can be "no universal standard", means taking account of the effect of chemicals on aquatic wildlife. "Were trying to derive environmental quality standards. These EQSs will be specific to individual pesticides."

Expressed as concentrations, some of the values are extremely low, especially for insecticides, he warned. For cyfluthrin (as in Baythroid) it is 100 times less than the drinking water level. But the herbicide trifluralin has an EQS figure of 20ppb.

The difficulty of translating such information into useful practical advice and getting it over to growers stimulated plenty of discussion in the workshops.

"If you spray directly beside a watercourse you can expect to get 5% of the chemical in the water," said Mr Tooby. Introducing a buffer zone of 5m (16ft) cuts that to about 0.5%. But it all depends on the environmental impact of the chemical, he explained.

Under the "uniform principles" of the EC approvals directive the PSD is "working towards" a toxicity exposure rating for each pesticide. "What were seeing is that some products need 15m, others just 2m."

Mr Barnden noted that Scotland has introduced a 2m (6.5ft) restriction for all chemicals. The current 6m figure on some labels seemed to be derived from a simple and somewhat arbitrary "half boom width" approach.

Not all growers will be equally affected by buffer zones. Fenland farmers could face particular problems. Dr Alistair Burn of English Nature said fen ditches were in effect "upside-down hedges" for wildlife, and wanted to know the impact of chemical "misuse".

Mr Barnden said specific studies on "point source" effects were under way in two catchments. If these showed problems remained from approved use, then the only way to make progress would be to change the approvals.

&#8226 NRA monitors only a third of the 450 pesticide active ingredients.

&#8226 "Acceptable" wildlife damage debatable.

&#8226 Tecnazene from potato stores accumulating in the Wash sediments.

&#8226 Label instructions on buffer zones likely to be insufficient.

&#8226 Need for widespread education and publicity acknowledged.

&#8226 Call for more information on alternative approaches and chemicals.

&#8226 Temporarily dry ditches remain legal watercourses.

&#8226 Needed to protect drinking water.

&#8226 Impact on wildlife is of growing concern.

&#8226 Range of buffer zones likely.

&#8226 Based on toxicity exposure ratings.

Working to keep pesticides out of water…Terry Tooby of the PSD(left) expects more grower guidelines, while Alan Barnden, NRA, advocates environmental quality standards for individual pesticides to protect wildlife.