Flora (Tejido vegetal)

outcomes between those presented in the literature and those presented here due to the differences between shale gas and CSG operations (as described in the Introduction and in Chapter 2) or due to various data sources that have been used in different studies. Data presented in Chapters 6 and 7 were from hospital admissions; however, there are also separate registers that can be used to assess perinatal outcomes and congenital anomalies in Queensland (Perinatal Data Collection), as well as cancer

notifications (Queensland Cancer Registry), which were not analysed for this thesis. These databases may provide more specific data for certain outcomes compared to the data contained in the hospital admissions database (i.e., the Queensland Hospital Admitted Patient Data Collection).

While it would have been ideal to use primary care data, as these data are the most reliable source of information for certain diseases or symptoms (Coons & Walker, 2008) and also allow investigation of conditions of less severity that do not require hospitalisation, it was not possible to source primary care data for this thesis. In order to obtain such data, primary care providers must have electronic records that are recorded in a consistent manner across practices and must be able to provide de-identified patient data in a timely way (Coons & Walker, 2008). Emergency Department records are another potential data source that could usefully inform this topic. Due to the lack of electronic networking in the hospitals located within each of the study areas for the duration of the study period (17 years), this was not a viable option for this programme of work. The use of the Queensland Hospital Admitted Patient Data Collection has a number of limitations. Databases such as this exist for administrative purposes and do not contain data collected for research purposes. Hence, they are limited in scope, and are sometimes not comparable with other datasets; however, these types of datasets are typically the only datasets available for this type of study (Coons & Walker, 2008).

While hospitalisation data (Chapters 6 and 7) are available at the individual level (episode-based), provision of these data for this study was at a group level (according to broad groups of SLAs) due to privacy and confidentiality concerns. This was a condition of data access and ethics. Additionally, a number of relevant confounders, such as gender, Indigenous status, access to healthcare, and

socioeconomic status, were not accounted for across the study areas. Accounting for such confounders is an important next step in this work. While the CSG and CM areas had similar proportions of Indigenous persons, the RA area had approximately three times as many Indigenous persons as the CSG and CM areas, which could be one factor that could influence health outcomes as a result of various determinants of health and poorer health outcomes.

Additionally, hospital admissions data were at the episode level. Unique identifiers were not provided and repeat admissions were included in the dataset; therefore, each case may not be unique

because a resident could have been admitted multiple times for the same primary diagnosis over the study time period. For this thesis, data were analysed at the broad ICD chapter code level rather than analysing specific sub-chapters. This approach was considered appropriate for this exploratory study as the analyses were preliminary and intended to guide future research. Further exploration within these disease chapters is required and strongly recommended.

The use of environmental data in this programme of work was limited due to the lack of

environmental data available. Chapter 7 used what limited environmental data were available to analyse hospital admissions data alongside CSG-specific resource development data. CSG well development activity was assessed via numbers of CSG wells; however, it is acknowledged that this measure was not a highly sensitive measure as it assumed that all individuals living in the CSG area who were admitted to hospital had the same level of exposure.

It is also important to note that the findings presented here assessed the early stages of CSG well development activity and was conducted in areas that are less densely populated (i.e., mainly rural/remote areas). This is in contrast to much of the research that has been conducted in the USA where there is a higher level of activity and the industry is more mature. For example, states like Colorado and Texas have more mature industries and are often situated closer to residential areas. Even shale gas production from the Marcellus Shale, which is more recent, has taken off at a much more rapid pace. So, while the CSG industry in Queensland is projected to expand, this research examined a lower level of activity relative to other areas where UNGD has been researched.

2 Summary

Overall, the ERHI assessment used in this research proved to be valuable for identifying evidence of health impact in the primary environmental setting of CSG and comparing how these health impacts differed from those in the alternative environmental settings. The early stages of the assessment enabled scoping out of certain elements that could not be included due to various constraints and the process subsequently allowed for successful assessment of available data, including limited environmental data.

The lack of baseline health data in Queensland means that data were unavailable from which to assess changes over time with respect to CSG development. Typically, datasets are often unavailable for every ideal measure of interest; therefore, the ERHI assessment was completed using the data that do exist and that can be accessed, which allows for providing evidence (or lack thereof) of health impact in the setting of interest.

While UNGD is expanding globally, there are still many unknowns in terms of its impacts. It is possible that some ERHIs could manifest years after this research was conducted due to lag times in exposure and subsequent disease development, meaning that some of the health outcomes may not yet be present. Therefore, it is more likely that potential short-term ERHIs were assessed with the approach used in this thesis. Additionally, the findings of this study do not allow for assumptions of causality, which would require more in-depth epidemiological studies and more specific data to make any causal links.

Rather, the findings presented here are a way to identify areas where more in-depth research should

occur, with the use of more appropriate study designs and more sophisticated data, to further examine the areas of interest that were identified in this thesis.

The evidence regarding health impacts presented here was derived from an analytical cross-sectional study and a retrospective cohort study, which included the use of individual data classified by broader areas. Other approaches were considered; however, study designs, such as a prospective cohort study, were not feasible for this programme of work due to financial and time constraints. Therefore, the data used in this assessment were appropriate for the objectives discussed in the Introduction.

While important to consider, the limitations of the ERHI assessment presented here should be considered in the context of the strengths of this research. This is the most detailed study to date in Australia regarding the health impacts of UNGD activity, particularly with respect to CSG development.

Health impacts were measured using subjective and objective data, representing different levels of condition severity. This study represents an important advancement in this field, provides evidence on which future research can be based, and allows for further elucidation of possible health impacts of UNGD activity.

Conclusion

The environmentally-related health impact (ERHI) assessment presented in this thesis allowed for the investigation of the impact of coal seam gas (CSG) development through exploring residents’

subjectively and objectively measured health experiences across three study areas, which were synthesised to present some evidence of health impact in the CSG study area. This was an exploratory study that addressed the broad research question and aim outlined in the Introduction. Specifically, ERHIs associated with CSG development in Queensland, Australia were addressed.

This thesis presented some important steps towards addressing gaps in the knowledge about the ERHIs associated with CSG development by using an ERHI assessment to comparatively assess these impacts. This assessment used three different environmental settings in three geographical study areas, building the evidence base for ERHIs related to CSG development in Queensland, Australia.

The output associated with each of the identified thesis objectives helped to address the overall research question (i.e., What are the environmentally-related health impacts of CSG development in Queensland, Australia?), which has been answered through the use of the ERHI assessment. The

assessment presented some evidence of health impact associated with CSG development for a number of health outcomes, meaning that residents living in the CSG area did have poorer health outcomes over time. The evidence of adverse health impact covered the majority of the International Classification of Diseases (ICD) chapters. Most notable were health outcomes associated with all-cause hospitalisations, as well as diseases of the eye.

There was also evidence of higher levels of self-reported environmental distress for certain measures in the CSG area compared with the levels in the comparative rural/agricultural environmental setting, which could be indicative of certain environmental distress measures being associated with resource development activity. While exposure categorisation was broad, there is some factor (or are some factors) that have contributed to residents in the CSG area presenting poorer health outcomes for certain measures over the time period of CSG development.

The thesis met the objectives, proposed in the Introduction, Section 4.2, which were as follows:

 The current strength of evidence of health impact from unconventional natural gas development (UNGD) was reviewed to understand the current evidence base and to guide development of the assessment, including the environmental settings (Chapter 2);

 Environmental settings were determined and related health indicators were selected (discussed in Chapters 1, 3, and 4) so that the environmentally-related health impacts of UNGD could be investigated on an exploratory basis;

 Geographic areas in Queensland (relevant to the environmental settings) were identified and delineated based on land use activities, populations, and available data (Chapter 3);

 Data were collected, analysed, and interpreted using the following:

o Coal seam gas production, as well as CSG well development numbers, to serve as a proxy for potential environmental impact of UNGD activities (addressed in Chapters 3 and 7),

o Subjectively measured self-report health data by residents in the three study areas (Chapter 5), and

o Objectively measured health data through hospital admissions data over 17 years in the same three areas (Chapter 6), as well as hospital admissions data in the CSG area in conjunction with CSG well development activity (Chapter 7);

 The findings on evidence of CSG health impact were synthesised and reported, along with the implications of the study findings (Chapters 7 and 8); and

 The results from this assessment informed areas that need to be researched further to examine these preliminary findings more in-depth.

1 Recommendations

The intent of this programme of work was to use the ERHI assessment to explore signs of impact of significant anthropogenic changes potentially brought about by CSG development using comparative environmental settings and their respective study areas while minimising the effect of potential

confounders such as age. Such exploration was set up to guide further research and several areas have been identified that should be explored further. Considering this, a number of recommendations have emerged from the process, many of which have already been discussed in the previous chapters.