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Chemical Use Risk Assessment

Spraying, spray drift and off-target damage

Spraying agricultural chemicals, whether from the ground or the air, needs to be properly planned and carefully executed, to minimise the risk of off-target chemical movement.

As an agricultural chemical user, you have a legal obligation to ensure that the chemicals you apply stay within the target area.

It is an offence to undertake agricultural spraying which:

  • injures any plants or stock outside of the target area
  • injures any land outside the target area so that growing plants, or keeping stock on that land would result in contamination, or
  • is likely to contaminate any agricultural produce derived from plants or stock outside the target area.

Spray drift and off-target damage

Spray drift is the most common cause of off-target chemical movement. It can injure or damage plants, animals, the environment or property, and even affect human health.

‘Drift’ is the airborne movement of agricultural chemicals as droplets, particles or vapour (see ‘Chemical formulations and vapour drift’ below).

Tips to minimise off-target spray drift

A combination of factors can contribute to spray drift, including the volatility of the chemical, weather conditions, equipment and droplet size. Below are some handy tips to help chemical users minimise off-target spray drift.

  • Always read and follow the product label directions, including any restrictions. Many labels now detail weather conditions, droplet size, equipment and spray drift restraints and/or mandatory no-spray zones to help users manage drift.
  • Choose a chemical formulation  that is less likely to drift off-target (e.g. use amine formulations of 2,4-D instead of 2,4-D high volatile esters which are more prone to drift as vapour during or after application).
  • Check for susceptible plants, animals and areas (e.g. stream, bee hives) close to the target area and put strategies in place to protect them from drift (e.g. use a buffer zone or leave an unsprayed buffer next to a susceptible crop).
  • Discuss your spray plans with neighbouring properties, particularly if you plan to spray near a sensitive crop or area. This provides them with the opportunity to implement protective measures on their property if needed and can help avoid complaints later on.
  • Ensure your equipment is set up and calibrated correctly.
  • Use a nozzle or sprayer setting that produces the largest possible droplet size (coarsest spray quality) to reduce the risk of drift without compromising the efficacy of the chemical.
  • Before you start, check that the weather conditions are suitable for spraying (i.e. wind speeds between 3-15 km/h, blowing away from sensitive crops/areas, Delta T between two and eight, temperature below 28oC, no inversion layer present). If the weather is unstable or unpredictable, don’t spray. Continue to monitor weather conditions while spraying and stop spraying if it turns unfavourable.

Risk assessment for vertebrate pest control using 1080 pest animal bait products

The bait user is responsible for assessing and managing the risks associated with the use of 1080 pest animal bait products. Completing a 1080 pest animal bait risk assessment will help you to determine if 1080 baiting is an appropriate control option and, if so, how much bait will be needed, what the risks are and how these risks will be managed.

A 1080 pest animal bait risk assessment provides the 1080 bait user with a checklist of actions that need to be undertaken prior to, during and after baiting. It covers the identification of hazards (i.e. toxicity to target and non-target species) and the potential for non-target species to be exposed to bait. A 1080 pest animal bait risk assessment will enable 1080 bait users to identify and minimise the risks associated with the use of 1080 pest animal bait products.

More information is provided in the Chemical Use Application section of the manual.



Veterinary Chemicals