摘要：

本文对长江河口地区1960～1985年间78口钻井中的各层承压水进行了245个水化学样品测试，分析内容包括K+、Na+、Ca²+、Mg²+、NH4+、Al³+、Cl-、HCO₃-、CO₃₂-、SO₄₂-离子含量以及酸碱性、温度等项目。其中第I层有样品24个；II层有63个；III层有53个；IV层有70个；V层有35个。测试时采用平行双样进行精度控制，水质分析的结果，按阴阳离子毫克当量总和的平衡关系进行检查，超出允许误差及时进行复检。
为了研究各承压含水层咸、淡水界面分布的变化，我们将矿化度作为水质指标，并利用人工神经网络技术进行了计算机模拟。结果表明，本区第四纪地层中各含水层水质的时空分布格局主要受第四纪海平面波动控制；IV、V含水层中的微咸水、咸水的分布可能受上层咸水通过越流污染下层淡水所致。对II、III含水层在二十世纪六十年代和八十年代两阶段水质分布的分析发现，含水层内淡水区在上海市区有向东南和西北方向明显扩展的趋势。造成这种现象的主要原因在于二十世纪七十和八十年代，上海市区地下水开采量逐年压缩，并开展了人工回灌（均为淡水），从而阻止了由于二十世纪六十年代市区过量抽取地下水而引起的地面沉降等问题。

Abstract:

The present database was established primarily on the basis of 245 water samples obtained from the Quaternary confined aquifers in 78 hydrologic boreholes recovered during 1960~1985.  The analytic items include the concentrations of K+, Na+, Ca²+, Mg²+, NH4+, Al³+, Cl-, HCO₃-, CO₃₂-, and SO₄₂-, and the values of PH and temperatures.  There were 5 Quaternary aquifers (I-V, from coretop downward) and 1 phreatic (on the core toppest) defined.  Of which, 24 water samples come from aquifer I, 63 from aquifer II, 53 from aquifer III, 70 from aquifer IV, and 35 from aquifer V.  When analysis, parallel test was applied to monitor the precision.  Analytic result was checked according to equilibrium relation of the sum of cations and anions (units in meq/l), and would be retested if the errors were beyond the permissive range.
    In order to study the movement of saltwater-freshwater interfaces in the confined aquifers, total dissolved solids (TDS) in groundwater was used as index of water quality.  Artificial neural network applied as a tool to simulation of the TDS distribution in those 5 aquifers. The results demonstrated that TDS distribution in groundwater, which is in fully agreement with the occurrence of 4-7 marine transgressions in intensity in the study area during Quaternary, is affected by sea level fluctuation.  Saltwater in aquifers IV and V is very localized but fluctuated apparently.  Leakage processes, which may result from groundwater withdraw, most likely influence their movement.  After groundwater formation, leakage action in local area can cause mixing of different layers of groundwater and thus change the water quality.  Data comparison in aquifers II and III were made between 1960s and 1980s.  The result indicates that the freshwater tend to flow outward (northwest and southeastward) from Shanghai city to its suburb area.  This phenomenon is interpreted as heavily reinjection of the freshwater after 1980s, to prevent large-scale subsidence that had occurred during 1960s, due to intensifying human activity, such as underground water exploitation.