Assessing potential environmental contamination from compound 1080 (sodium monofluoroacetate) in bait dust during possum control operations

Abstract

The risk of environmental contamination by 1080 from bait dust during possum control operations was assessed after three such operations. This research was prompted by the lack of data on the potential risk of poisoning invertebrates in leaf litter by 1080 from bait dust. Cereal baits containing 0.15% 1080 were aerially applied and samples of bait dust (from application of bait), plants, leaf litter, soil, and water (from within and up to 1000 m outside the treatment areas) were collected prior to and up to 30 days after bait application. A maximum concentration of 25.2 μg 1080 m‐2 was detected in bait dust (from dust collectors) within the control zone immediately after aerial application of 1080 baits. Lower concentrations of 1080 were found outside the treatment areas indicating relatively little drift of bait dust. There were detectable short‐term 1080 residues in water, plant, leaf litter, and soil samples after two of the three baiting operations. However, the residues were very low indicating only minor contamination by 1080. Using the maximum concentration of 1080 found in leaf litter, and literature LD50 values for invertebrates, these results indicate that 1080 derived from bait fragments and bait dust does not pose a significant risk of poisoning to resident leaf litter invertebrates. However, the presence of 1080 baits on the ground may still pose a risk to those invertebrates in close proximity to these baits.