Quantification of hydrogen cyanide as a potential decomposition product of ethanedinitrile during pine log fumigation

Abstract

Background: The Stakeholders in Methyl Bromide Reduction (STIMBR) are evaluating ethanedinitrile (EDN) as an alternative fumigant to methyl bromide for use as a phytosanitary treatment for pine logs (Pinus radiata D.Don). Ethanedinitrile is hypothesised to decompose into hydrogen cyanide (HCN) in the presence of water. This process, if it occurs, is of particular interest because it may influence the efficacy and emissions data needed for commercialisation. Methods: The concentrations of EDN and HCN were measured in the treated space (28 L fumigation chambers) without (n = 1) and with pine log sections (n = 3; 46 ± 1.4% load factor) at 10 or 20 °C in a simulated commercial fumigation. Results: On average, the cylinder of EDN tested contained 34.6 g m− 3 HCN (or 3.1%), which corresponds to a concentration of 0.8 g m− 3 (or 0.07%) in the treated space for a 50 g m− 3 EDN dose (commercial rate in Australia). This level of HCN is likely a result of the manufacturing process, whereby HCN is oxidised to produce EDN. During fumigation, HCN was detected in the treated space at relatively low concentrations, which did not significantly change over time. This indicates that HCN is not produced in substantial amounts during fumigation and that, as a result, insect efficacy is unlikely to be affected by low unchanging (P = 0.055) concentrations of this compound in the treated space. Conclusions: The results of this work support the statement that EDN is not significantly converted to HCN during the treatment of recently harvested pine logs.