Pesticides & Herbicides

Pesticides and Herbicides

Pesticides and herbicides can enter rivers, streams or groundwater bodies used as sources for drinking water supplies through direct application, run-off, aerial drift or by seeping through the soil.

Prevention is better – Do you know that one foil seal contains enough pesticide to breach 0.21 microgram/L level along 30km of a typical stream (width = 1m, depth = .03m)?

General advice for users to minimise point-source pesticide emissions (typical entry routes: mixing, filling, washing, spillage, leaks)

·        Be aware of location of water bodies and if they are used to supply drinking water.

·        Do not apply if heavy rain is forecast within 48 hours.

·        Do not apply to saturated or frozen ground.  Avoid applications to

soils that are prone to repeated water logging.

·        Do not apply if field drains are overflowing.

·        Do not apply on areas with channels that drain directly to water.

·        Do not apply to dry, cracked soil.

·        Do not apply on poorly draining wet soils that slope strongly

towards a water body.

·        Consider grassed buffer strip to protect vulnerable water bodies.

·        Ensure application equipment is properly calibrated.

·        Do not spray in windy conditions.

·        Keep the spray boon as low as possible.

·        Use the coarsest appropriate spray quality.

·        Use drift-reducing nozzles if possible.

·        Consider lower application rates, different application timings, alternative treatments, etc.

The labels and information supplied with plant protection products often specify measures to reduce aquatic exposure, e.g. a buffer zone of a particular width.  If a buffer zone is specified on the label of a plant protection product, it must be complied with.  An adequate buffer zone is an untreated strip of a specified minimum width between the edge of a water feature (such as a ditch, stream, pond, river or lake) and the edge of the treated area adjacent to the water body.

Always consider alternatives to pesticides and herbicides.

Useful guidance documents on promoting biodiversity and encouraging pollinators in a range of environments have been prepared by the national biodiversity centre. Each of these documents contains advice on alternatives to herbicides and pesticides. Please refer to             

Good practice guide for empty pesticide containers.

General guidelines for pesticides.

Pesticides - Advice for Gardeners and Household Users

Pesticides - Advice for Farmers and Other Professional Users

Protecting Drinking Water from Pesticides

Herbicide Use in Grassland

Teagasc and the Department of Food, Agriculture and the Marine Pesticide Best Practice Demonstration video