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Protecting Drinking Water from Pesticides

Drinking water monitoring results for Ireland show that a number of commonly used pesticides are being detected more frequently in recent years. Careless storage, handling or use of pesticides, or improper disposal of empty pesticide containers, can easily cause breaches of the legal limit for pesticides in drinking water. 

Pesticides is a broad term which encompasses various types of pest control agents including herbicides, fungicides, insecticides, seed dressings and rodenticides. 

How do pesticides get into drinking water? 

Pesticides can enter water bodies from: 

  • Point sources – leaks from storage areas; spills or drips from handling operations such as mixing, filling and washing equipment; or
  • Diffuse sources – releases that occur during or after application, such as spray drift, runoff or drainage inputs. Water bodies are particularly vulnerable to runoff or washoff inputs from hard or compacted surfaces  

DOs when using pesticides: 

  • Read the product label instructions carefully and plan the treatment in advance, taking care to ensure strict compliance with the specified conditions of use. Follow all health and safety instructions.
  • Inform yourself of the location of all nearby water bodies (ditches, streams, ponds, rivers, lakes and springs).
  • Find out if any groundwater body or surface water body in your locality is used as a drinking water source and, if so, the location of the nearest abstraction point. Ensure compliance with the safeguard (no-use) zones around drinking water abstraction points.
  • Ensure that the pesticide products are stored in a secure, dry area which cannot result in accidental releases to drains, wells or water courses.
  • Ensure that any pesticide application equipment used is properly calibrated and in good working order.
  • Take every precaution during mixing and preparation of pesticides for application to avoid spills and drips. Minimise water volumes (rain and washings) on the handling area.
  • Consider using drift-reducing nozzles if spraying. Keep the spray boom as low as possible to the ground and use the coarsest appropriate spray quality.
  • Clean and wash down application equipment at the end of the day, preferably in the field and well away from water bodies or open drains. Tank washings should be sprayed onto a previously sprayed area, on a section far away from any water body, observing the maximum dose for that area.
  • Ensure that empty, triple-rinsed containers and foil caps are disposed of in accordance with the Good Practice Guide for Empty Pesticide Containers.

DON’Ts when using pesticides:

  • DON’T fill application equipment directly from a water body.
  • DON’T perform handling operations (filling, mixing or washing the sprayer) near water bodies, open drains or well heads. A distance of at least 10 metres should be maintained and preferably 50 metres, where possible.
  • DON’T spray if the target area is wet or if heavy rain is forecast within 48 hours after application.
  • DON’T apply pesticides during windy conditions.
  • DON’T apply pesticides near open drains, wells or springs.
  • DON’T apply pesticides on waterlogged or poorly draining soils that slope steeply towards a water body or on any other vulnerable area that leads directly to water
  • DON’T apply pesticides if field drains are flowing.
  • DON’T discard washings from application equipment down a drain or onto an area from which they can readily enter a water body 

Read also:

DAFM

Background Information

 Triple rinse procedure (PDF)

 

Control rushes using MCPA safely, correctly, and responsibly

Guide to demonstrate the correct procedures when applying pesticides to grasslands, with an emphasis on rush control by MCPA based products