Hageman Kimberly J, Field Jennifer A, Istok Jonathan D, Schroth Martin H
Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-7301, USA.
Environ Sci Technol. 2003 Sep 1;37(17):3920-5. doi: 10.1021/es0342042.
A method for estimating in situ transformation rates of sorbing solutes in groundwater is presented. The method utilizes a novel data processing technique called "forced mass balance" (FMB) to remove the effects of transport processes from reactant and product concentrations measured during single-well, "push-pull" tests. The effectiveness of the FMB technique was evaluated by quantifying errors in derived rates obtained by applying FMB to simulated push-pull test data generated by a numerical model. Results from simulated tests indicated that errors in derived rates increase as the test duration, groundwater velocity, and ratio of reactant to product retardation factors increase. In addition, errors in derived rates increase as the reaction rate constant and aquifer dispersivity decrease. As a demonstration, the FMB technique was used to derive an in situ reductive dechlorination rate for trichlorofluoroethene (TCFE) using data from a field push-pull test. Error analyses indicated that the in situ TCFE transformation rate was underestimated by a factor of 1.1-2. Thus, the FMB technique makes it possible to estimate in situ transformation rates of sorbing solutes and when FMB is coupled with computer modeling to estimate errors in derived in situ rates.
本文提出了一种估算地下水中吸附性溶质原位转化率的方法。该方法利用一种名为“强制质量平衡”（FMB）的新型数据处理技术，以消除在单井“推-拉”试验中测量的反应物和产物浓度中传输过程的影响。通过量化将FMB应用于数值模型生成的模拟推-拉试验数据所得到的推导速率中的误差，对FMB技术的有效性进行了评估。模拟试验结果表明，推导速率中的误差随着试验持续时间、地下水速度以及反应物与产物阻滞因子的比值增加而增大。此外，推导速率中的误差随着反应速率常数和含水层弥散度的减小而增大。作为示例，利用现场推-拉试验的数据，采用FMB技术推导了三氯氟乙烯（TCFE）的原位还原脱氯速率。误差分析表明，原位TCFE转化率被低估了1.1至2倍。因此，FMB技术使得估算吸附性溶质的原位转化率成为可能，并且当FMB与计算机建模相结合时，还能估算推导的原位速率中的误差。
