Impact of coal and coal seam gas industries on aquatic environments
thesisposted on 2022-03-28, 10:35 authored by Aal-e Ali
Energy generation and its resource utilization involves processes like the extraction of coal and coal seam gas (CSG) which generate produced water causing possible surface water, groundwater, and sediments pollution. This study aimed on the environmental impact evaluation along with the sustainable developments, particularly in field of coal and coal seam gas production. The study reports the impact of produced water and discharges from coal and coal seam mine's activities on high conservation environments. The objective of the thesis was to investigate chemical contamination of water and sediment along with the composition of / bioaccumulation in inhabitant macroinvertebrates and chlorophyll. The outcome of the objectives was taken as indicators of industrial pollution and environmental impairment. Extensive review precipitated into identifying the gaps in the reported work on the direct or indirect effects on sustainability of environment under continuous growth in energy consumption and coal and coal seam gas production. The water samples upstream and downstream from the discharge points were tested for water quality index (WQI) in comparison of national maximum admissible concentration (MAC) and their corresponding environmental impacts. Higher contamination of downstream samples was investigated for its toxicity and was used as an additional tool to assess water quality. The assessment culminated into newly proposed Environmental Water Quality Index (EWQI). 'Total Points' from 'Agency for Toxic Substances and Disease Registry (ATSDR)' being the basis for calculation validated EWQI as better index for impact evaluation. EWQI led to better trend in the impact evaluation of coal and coal seam gas mining activities on surface water quality. Similarly, the sediment samples were analysed for their size exclusion behaviour and contaminants adsorption. The contaminant analysis output was scrutinised on the basis of sediment quality guideline value (SQGL) for impact evaluation. It was also subjected to impact exploration by finding mean effective range median quotient (ERMQ) and environmental toxicity quotient (ETQ). The contaminants' toxic effect was investigated on the inhabitant invertebrates' taxa, bioaccumulation and chlorophyll. The study revealed that impacted water downstream of the mine discharge points contained higher metal content than the upstream reference locations above the Australia and New Zealand Environment Conservation Council and international water quality guidelines for freshwater stream. The major outliers to the guidelines were aluminium (Al), iron (Fe), manganese (Mn), nickel (Ni) and zinc (Zn). Toxicology indices of metals present in industrial discharges were used as an additional tool to assess water quality which lead the newly proposed Environmental Water Quality Index (EWQI) to better trend in the impact evaluation of coal and coal seam gas mining activities in environmental and health impact assessment. Various contaminants were measured to determine the sediment quality and arsenic, nickel, and zinc were found exceeding the Australian and New Zealand Environment and Conservation Council (ANZECC) guidelines. Degree of contamination (Cd), geoaccumulation index (Igeo), enrichment factor (EF), pollution load index (PLI) and sediment environmental toxicity quotients' increment in downstream sediment with the toxicology indices of metals present were used as tool to compare the level of environmental impact. Coal mining impacts were found to be substantially more than the coal seam gas production impact, mainly attributed to the different wastewater discharge licensing requirements which can be used as an additional model to assess the contribution of industrial and mining activities on aquatic environments. Investigation of macroinvertebrates and chlorophyll as indicators of industrial pollution and environmental impairment revealed change in abundance, taxonomic richness, and pollution sensitive macroinvertebrate groups. Aquatic invertebrates can absorb metals from water and they can serve as an indicator of ecotoxicological impacts of mining. A statistical evaluation of aquatic life and correlation of contaminant with the presence of community in ecosystem was assessed. A non-uniformity in the changes were observed indicating difference in tolerance level of different invertebrates. Finally, investigating the metal content in macroinvertebrates as indicators of pollution and environmental impairment revealed that certain metals were elevated within some of the aquatic invertebrate species indicating the presence of metal contamination as a function of both the ability of an individual species to regulate the metal intake and the concentration of metals in the environment. Elemental composition correlation indicated the phenomenon of filtering out Cr, Mn, Fe, Ni, and As for invertebrate survival. Certain metals, such as Al, Ti and Zn, were found to be in higher quantity in the invertebrates collected downstream the mining discharge locations. The objective of this thesis was to substantiate the effect of coal and coal seam gas production on the environment. The possibility of the environmental impairment with the type of processes involved in the production, waste generation and their disposal procedure were studied. The study provides the novel ideas for the need of thorough monitoring and licencing procedures for the sustainable industrialization. A baseline of the industrial constituents was established to understand geochemical process, resource utilization, and need for the revision of the coal mine run off management. The need for implementation of robust monitoring procedure was concluded.