Isotopic signatures of major methane sources in the coal seam gas fields and adjacent agricultural districts, Queensland, Australia

Abstract. In regions where there are multiple sources of methane (CH4) in close proximity, it can be difficult to apportion the CH4 measured atmosphere appropriate sources. Surat Basin, Queensland, Australia, coal seam gas (CSG) developments surrounded by cattle feedlots, grazing cattle, piggeries, mines, urban centres and natural CH4. The characterization carbon (?13C) hydrogen (?D) stable isotopic composition help distinguish between specific emitters However, Australia is a paucity data on various signatures different source types. This research examines whether dual used Basin. We also highlight benefits sampling at nighttime. During two campaigns 2018 2019, mobile monitoring system was detect plumes. Sixteen plumes immediately downwind from known (or individual facilities) were sampled analysed for their mole fraction ?13CCH4 ?DCH4 signatures. determined using Keeling plot method. These new then compared values documented reports peer-reviewed journal articles. CSG have ?55.6 ‰ ?50.9 ?207.1 ?193.8 ‰. Emissions an open-cut mine -60.0±0.6 -209.7±1.8 respectively. ground seeps (abandoned exploration wells) -59.9±0.3 -60.5±0.2 -185.0±3.1 -190.2±1.4 A river seep had signature -61.2±1.4 -225.1±2.9 Three dominant agricultural analysed. feedlot -62.9±1.3 -310.5±4.6 respectively, (pasture) -59.7±1.0 -290.5±3.1 piggery -47.6±0.2 -300.1±2.6 which reflects emissions animal waste. An export abattoir (meat works processing) -44.5±0.2 -314.6±1.8 plume wastewater treatment plant -177.3±2.3 attribution possible when both key categories CSG, waste feedlots water plants. Under most field situations alone will not enable clear attribution. It common Basin facilities co-located. Measurement assist apportionment such mixed.