Department of Geology, Federal University of Technology, Owerri, Imo State, Nigeria.
Department of Physics, University of Port Harcourt, Port Harcourt, River State, Nigeria.
Environ Monit Assess. 2022 Nov 18;195(1):123. doi: 10.1007/s10661-022-10643-2.
A near-surface resistivity investigation was undertaken to investigate soil contamination and aquifer vulnerability due to leachate percolation in a major dumpsite in Calabar. The study was undertaken using 2-D electrical resistivity tomography (ERT) and vertical electrical sounding. Ten traverse lines were created within and outside the dumpsite and geo-electric measurement was conducted using dipole-dipole and Schlumberger electrode configurations. Interpretation of the measured data was carried out using DIPROWIN and WinResist program. 2-D resistivity structures were produced, showing four resistivity layers. Conductive layers with a resistivity of less than 14Ωm were delineated as leachate infiltrated and soil-contaminated zones. The study has shown that leachate has spread across all the survey lines except the two control stations outside the dumpsite. The investigation has further revealed that leachate has percolated the subsurface up to 25 m in the area. Subsequently, twenty vertical electrical soundings were carried out to evaluate aquifer protective capacity/vulnerability in the area. The interpretation shows the area is underlain by four to five geo-electric layers. Total longitudinal conductance values were calculated. Two VES points (14 and 19), representing 10% of the sounding points, showed a weak protective capacity rating; eight VES points (1, 7, 9, 11, 12, 13, and 18), representing 35% of the soundings, showed a moderate protective capacity rating; ten VES points (2, 3, 4, 5, 6, 8, 10, 15, 16, 17, and 20), representing 55% of the total soundings, showed a good protective capacity rating. Three (3) hand-dug wells were sampled with the view to obtaining the groundwater and leachate flow direction within the dump vicinity. An electric water level recorder was used to determine the static water level (SWL) of the three wells, and the leachate flow direction was determined to be north-easterly.
在卡拉巴尔的一个主要垃圾场，为了调查沥滤液渗透造成的土壤污染和含水层脆弱性，进行了一项近地表电阻率调查。该研究使用二维电阻率层析成像（ERT）和垂直电测深进行。在垃圾场内外创建了 10 条测线，并使用偶极-偶极和 Schlumberger 电极配置进行了地质电测量。使用 DIPROWIN 和 WinResist 程序对测量数据进行解释。制作了二维电阻率结构，显示了四个电阻率层。电阻率小于 14Ωm 的导电层被划定为沥滤液渗透和土壤污染区。研究表明，沥滤液已经扩散到所有的勘测线路，除了垃圾场外的两个控制站。调查还进一步表明，沥滤液已经渗透到该地区地下 25 米处。随后，进行了 20 个垂直电测深，以评估该地区的含水层保护能力/脆弱性。解释显示该地区由四到五个地质电层组成。计算了总纵向电导率值。两个 VES 点（14 和 19），代表了 10%的测深点，显示出较弱的保护能力等级；八个 VES 点（1、7、9、11、12、13 和 18），代表了 35%的测深点，显示出中等的保护能力等级；十个 VES 点（2、3、4、5、6、8、10、15、16、17 和 20），代表了 55%的总测深点，显示出良好的保护能力等级。为了获得垃圾场附近地下水中的沥滤液流向，对三口手动挖掘的水井进行了采样。使用电水位记录仪确定了三口井的静态水位（SWL），并确定沥滤液流向为东北方向。
