Estimation of the leak term and sensitivity analysis at a LUST groundwater system under data scarcity

摘要

With the development and popularization of automobiles in China, the Leaking Underground Storage Tanks (LUSTs) containing gasoline have become potential sources of groundwater contaminant. However, in China information on the occurrence of LUSTs in groundwater is scarce. Based on general enquiries and investigation of 22 LUST sites, a typical one located in Suzhou city was selected to explore the existence of tank leakage and assess its effect on the groundwater quality. Based on the proposition that anaerobic benzene degradation occurs in the aquifer, MODFLOW and MT3DMS, two commonly used groundwater flow and transport simulators, are introduced to simulate the contaminant transport of benzene in groundwater, and determine the leak location and the leak rate at the same time. Considering there are broad categories of modelling uncertainty, the sensitivity analysis is used in this study to address the relative importance of eight model parameters in the established model. This study demonstrates a general framework for identifying the contaminant sources and evaluating the potential impacts of the LUSTs on drinking groundwater sources using numerical simulation models under data scarcity.