Environmentally-related health impacts of coal seam gas development: An impact assessment approach in Queensland, Australia

Abstract

Queensland, Australia has a large mining industry and has been extracting coal seam gas (CSG) on an increasingly larger scale in recent years. CSG is a type of unconventional natural gas. Historically, concerns associated with unconventional natural gas development (UNGD) have come from areas where types of UNGD other than CSG are predominant. While shale gas and CSG development are not identical, there is an underlying theme of community concern about the potential environmentally-related health impacts (ERHIs) of such development. A problem for Australia is that there is a dearth of research on ERHIs associated with CSG, in particular, in Queensland. The purpose of this research was to explore the ERHIs associated with CSG development in Queensland and suggest areas for further research. This exploratory study used three environmental settings: a CSG setting and two alternative settings (i.e., coal mining and rural/agricultural). The CSG study area served as the primary setting, as this is a fairly new industry and there is as yet no substantial body of knowledge to fully understand what the health impacts may be. Data concerning CSG gas well numbers, as well as other ‘macro’ environmental determinants, such as production figures, were used to assess increased environmental activity within these areas. Subjective health outcomes in residents were assessed through a self-report survey. This was to determine any differences in health and psychosocial impacts of environmental change between the respondents living in each environmental setting. In addition to the subjective health outcomes data, objective health outcomes were examined through hospital admissions data for the period 1995-2011 for all three areas. These data were compared between the three areas for differences in hospitalisation rates over time in relation to various conditions according to the International Classification of Diseases (ICD) chapters. Hospital admissions data were also examined in conjunction with CSG well development activity data in the CSG area to gather evidence of CSG health impact using limited available environmental data. The findings showed that the self-reported health status of respondents in the CSG area did not differ compared to the two other study areas; however, respondents did self-report higher levels of environmental distress for some measures. There were significant increases in all-age hospitalisation rates over time in the CSG area compared to the coal mining and rural areas for ‘All-cause’ hospitalisation rates (RR: 1.01; 95% CI: 1.00-1.01 compared to the coal mining area and RR: 1.01; 95% CI: 1.01-1.02 compared to the rural area). Significant increases were also seen for admission rates within ICD chapters related to ‘Blood/immune’ diseases (RR: 1.08; 95% CI: 1.05-1.12 compared to the coal mining area and RR: 1.05; 95% CI: 1.01-1.09 compared to the rural area) and ‘Eye’ diseases (RR: 1.04; 95% CI: 1.02-1.06 compared to the coal mining area and RR: 1.04; 95% CI: 1.02-1.06 compared to the rural area). The child/adolescent and adult cohorts in the CSG area showed increases in hospitalisation rates over time compared to the other two study areas. Strongest observed effects for evidence of health impact in the CSG area were found to be for ‘All-cause’ hospitalisation rates for all-ages (RR: 1.12; 95% CI: 1.08-1.15 for the low vs very low period of CSG development; RR: 1.16; 95% CI: 1.12-1.19 for the medium vs very low period of CSG development; and RR: 1.25; 95% CI: 1.21-1.29 for the intense vs very low period of CSG development), as well as 35-44 year olds (RR: 1.16; 95% CI: 1.09-1.23 for low vs very low; RR: 1.26; 95% CI: 1.19-1.33 for medium vs very low; and RR: 1.38; 95% CI: 1.31-1.46 for intense vs very low). This suggests a dose-response relationship between hospitalisation rates due to any cause and increasing CSG development. Strongest observed effects were also noted for diseases of the ‘Eye’ for all-ages (RR: 1.16; 95% CI: 1.02-1.33 for low vs very low; RR: 1.34; 95% CI: 1.18-1.52 for medium vs very low; and RR: 1.89; 95% CI: 1.66-2.14 for intense vs very low). The estimates presented here suggest a dose-response relationship for hospitalisation rates associated with ‘Eye’-related diseases and CSG development. This research serves as an important first step towards exploring ERHIs associated with CSG development in Queensland and highlights areas that need to be investigated further. The ERHI assessment revealed some evidence of health impact associated with CSG development; however, there is a need for more environmental data so that these data can be assessed alongside health outcomes data. This research presents evidence on which future research can be based, which can further elucidate any possible ERHIs associated with UNGD activity. The ERHI assessment framework used for this study provided a useful way of assessing ERHIs in an environmental setting of interest (i.e., CSG) and alternative settings (i.e., coal mining and rural/agricultural). Such a framework can be applied to other settings and in other geographic localities.