Assessment of Geogenic Contaminants in Water Co-Produced with Coal Seam Gas Extraction in Queensland, Australia: Implications for Human Health Risk

Abstract

Organic compounds in Australian coal seam gas produced water (CSG water) are poorly understood despite their environmental contamination potential. In this study, the presence of some organic substances is identified from government-held CSG water-quality data from the Bowen and Surat Basins, Queensland. These records revealed the presence of polycyclic aromatic hydrocarbons (PAHs) in 27% of samples of CSG water from the Walloon Coal Measures at concentrations <1 µg/L, and it is likely these compounds leached from in situ coals. PAHs identified from wells include naphthalene, phenanthrene, chrysene and dibenz [a,h]anthracene. In addition, the likelihood of coal-derived organic compounds leaching to groundwater is assessed by undertaking toxicity leaching experiments using coal rank and water chemistry as variables. These tests suggest higher molecular weight PAHs (including benzo[a]pyrene) leach from higher rank coals, whereas lower molecular weight PAHs leach at greater concentrations from lower rank coal. Some of the identified organic compounds have carcinogenic or health risk potential, but they are unlikely to be acutely toxic at the observed concentrations which are almost negligible (largely due to the hydrophobicity of such compounds). Hence, this study will be useful to practitioners assessing CSG water related environmental and health risk. OPEN ACCESSGeosciences 2014, 4 220

Economic Synergies from Tighter Agri-Business and Coal Seam Gas Integration

“…levels fall characteristically between 3000 and 15,000 milligrams per litre (mg/L); CSGAW is typically classified as 'brackish water' as it has total dissolved solids (TDS) ranging between 1200 and 7000 mg/L [6,37]. Adequate water treatment and careful management practices are critical to prevent harmful effects on the environment and end user [38].…”

Coexistence Opportunities for Coal Seam Gas and Agribusiness

“…CSGAW is categorized as “brackish water” because of its characteristic total dissolved solids (TDS) range of 3,000 to 15,000 milligrams per liter (mg/L) (Stearman et al. ; Nghiem et al. ).…”

“…Other chemical constituents may include chemicals used on the CSG operator's sites during well construction, such as cement, drilling operations (drilling mud), reservoir stimulation (fracture fluid), and maintenance activities (workovers) (O'Kane 2013). Table 1 summarizes the typical CSGAW water quality from the Surat Basin. CSGAW is categorized as "brackish water" because of its characteristic total dissolved solids (TDS) range of 3,000 to 15,000 milligrams per liter (mg/L) (Stearman et al 2014;Nghiem et al 2011). Careful water management (including appropriate treatment before use) and water-quality monitoring is required to prevent detrimental effects on the environment or the end user (Jangbarwala 2007;Khan and Kordek 2014).…”

A Generic Method for Predicting Environmental Concentrations of Hydraulic Fracturing Chemicals in Soil and Shallow Groundwater

“…The Assessment investigated and characterized the risks to human health and the environment from surface handling of chemicals used in CSG extraction during the period 2010 to 2012. This included the transport, storage and mixing of chemicals, and the storage and handling of water pumped out of CSG wells (flowback and produced water) that contain chemicals originating from coal seam formations [2][3][4][5][6] and chemical residues from the hydraulic fracturing operation [7][8][9][10][11][12][13]. The risks of chemical use are likely to be greatest during surface handling because prior to mixing and injection, the chemicals are present in undiluted form [14][15][16][17][18][19][20][21][22][23][24].…”