Sodium fluoroacetate (compound 1080) uptake by Puha, a culturally-important food plant

Abstract

Sodium fluoroacetate (Compound 1080) is a key tool in the control of possums, and the most extensively used vertebrate pesticide in New Zealand (Livingstone 1994; Morgan 1994a, b; Thomas 1994; Gillies and Pierce 1999; Powlesland et al. 1999; Sherley et al. 1999; Styche and Speed 2002). The most common method of control using this pesticide is via aerial application of cereal or carrot baits containing 1080 (Eason et al. 2000). This is a cost effective means of reducing possum populations by more than 90% (Eason et al. 1994, Veltman and Pinder 2001). Despite the efficiency of aerial 1080 application for reducing possum population numbers, support amongst Māori is mixed. In general, Māori oppose the use of toxins in the environment, despite the benefits to be had through the control of pests. In particular, there is much opposition around the aerial use of 1080 (Ogilvie et al. in press). Para (1999) documented concerns of Māori regarding the fate of 1080 in wild harvested kai (food) species. The risk of secondary poisoning of people using kai resources has previously been identified as key research by the Animal Health Board (AHB), Environmental Risk Management Authority (ERMA) and Māori. During aerial application of 1080 baits, there is the possibility that 1080 may leach from baits and be taken up by nearby plants (Atzert 1971; Rammel and Fleming 1978). More recent laboratory research has shown that 1080 can be taken up by terrestrial and aquatic plants, including Myriophyllum triphyllum, a native aquatic New Zealand plant (Ogilvie et al. 1995); Elodea canadensis, an introduced aquatic species (Ogilvie et al. 1996); and broadleaf and ryegrass, both terrestrial species (Ogilvie et al. 1998). In a field setting where a simulated aerial 1080 operation has been conducted, low concentrations of 1080 were found in Coprosma robusta, or karamuramu, a native species used as medicine by Māori; however no 1080 was found in Asplenium bulbiferum, or pikopiko, a native species commonly consumed by Māori (Ogilvie et al. 2006). This report is part of a research programme conducted to investigate the uptake and persistence of 1080 in watercress and puha. This report focuses only on data generated from the puha component of this work. The watercress component will be reported at a later date.