Source-pathway-receptor analyses involving solute migration pathways through soil and shallow groundwater are typically undertaken to assess how people and the environment could come into contact with chemicals associated with coal seam gas operations. For the potential short-term and long-term release of coal seam gas fluids from storage ponds, solute concentration and dilution factors have been calculated using a water flow and solute transport modelling framework for an unsaturated zone-shallow groundwater system. Uncertainty about dilution factors was quantified for a range of system parameters: (i) leakage rates from storage ponds combined with recharge rates, (ii) a broad combination of soil and groundwater properties, and (iii) a series of increasing travel distances through soil and groundwater. Calculated dilution factors in the soil increased from sand to loam soil and increased with an increasing recharge rate, while dilution decreased for a decreasing leak rate and leak duration. In groundwater, dilution factors increase with increasing aquifer hydraulic conductivity and riverbed conductance. For a hypothetical leak duration of three years, the combined soil and groundwater dilution factors are larger than 6980 for more than 99.97% of bores that are likely to be farther than 100 m from the source. Dilution factors were more sensitive to uncertainty in leak rates than recharge rates. Based on this dilution factor, a comparison of groundwater predicted environmental concentrations and predicted no-effect concentrations for a subset of hydraulic fracturing chemicals used in Australia revealed that for all but two of the evaluated chemicals the estimated groundwater concentration (for a hypothetical water bore at 100 m from the solute source) is smaller than the no-effect concentration for the protection of aquatic ecosystems.

中文翻译：

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一种预测土壤和浅层地下水中水力压裂化学品环境浓度的通用方法

源-途径-受体分析涉及通过土壤和浅层地下水的溶质迁移途径，通常用于评估人类和环境如何接触与煤层气作业相关的化学品。对于煤层气流体从储存池中潜在的短期和长期释放，已使用非饱和带浅层地下水系统的水流和溶质输运建模框架计算了溶质浓度和稀释因子。稀释因子的不确定性针对一系列系统参数进行了量化：(i) 蓄水池的渗漏率与补给率相结合，(ii) 土壤和地下水特性的广泛组合，以及 (iii) 一系列增加的穿过土壤的行进距离和地下水。土壤中计算的稀释因子从沙土到壤土增加，并随着补给率的增加而增加，而稀释率随着泄漏率和泄漏持续时间的降低而减少。在地下水中，稀释因子随着含水层水力传导率和河床传导率的增加而增加。对于三年的假设泄漏持续时间，对于可能距离源头超过 100 m 的超过 99.97% 的钻孔，土壤和地下水稀释系数的总和大于 6980。稀释因子对泄漏率的不确定性比补给率更敏感。基于这个稀释因子，