Use of a time-domain electromagnetic method with geochemical tracers to explore the salinity anomalies in a small coastal aquifer in north-eastern Tunisia
Use of a time-domain electromagnetic method with geochemical tracers to explore the salinity anomalies in a small coastal aquifer in north-eastern Tunisia
复制标题
使用时域电磁方法和地球化学示踪剂探索突尼斯东北部沿海小型含水层的盐度异常
DOI：
10.1007/s10040-014-1180-7
复制
发表时间：
2014
影响因子：
2.8
通讯作者：
J.
中科院分区：
文献类型：
--
作者：
Chekirbane;A.;Tsujimura;M.;Kawachi;A.;Lachaal;F.;Isoda;H.;Tarhouni;J.
研究区域是突尼斯东北部的一个小的沿海平原。它由一个短暂的河流网络排水，并受到几种污染物的排放，如来自邻近石油公司的油田盐水和位于平原上游的Somâa市的废水。此外，含水层沿海部分附近的水头低于海平面，表明可能发生海水入侵。在Wadi Al Ayn和Daroufa平原进行了基于28次测深的时域电磁测量，以确定地下咸水。根据钻孔资料标定的电阻率二维拟剖面，识别了咸水体的范围。结合地化示踪剂和电阻率数据对地下水盐渍化成因进行了判别。在平原的上游部分，油田盐水通过Wadi Al Ayn的桑迪床的渗透似乎对地下水盐碱化产生了相当大的影响。然而，在含水层的沿海部分，地下水盐碱化是由于海水入侵造成的，盐水正在到达距离海岸线约1.3公里的内陆地区。从反演的氯化物数据得出的咸水体的贡献率在油田卤水中为1 ~ 13%，在海水中为2 ~ 21%。
The study area is a small coastal plain in northeastern Tunisia. It is drained by an ephemeral stream network and is subject to several pollutant discharges such as oilfield brine coming from a neighboring oil company and wastewater from Somâa city, located in the upstream of the plain. Furthermore, a hydraulic head near the coastal part of the aquifer is below sea level, suggesting that seawater intrusion may occur. A time-domain electromagnetic (TDEM) survey, based on 28 soundings, was conducted in Wadi Al Ayn and Daroufa plains to delineate the saline groundwater. Based on longitudinal and transversal resistivity two-dimensional pseudosections calibrated with boring data, the extent of saline water was identified. Geochemical tracers were combined with the resistivity dataset to differentiate the origin of groundwater salinization. In the upstream part of the plain, the infiltration of oilfield brine through the sandy bed of Wadi Al Ayn seems to have a considerable effect on groundwater salinization. However, in the coastal part of the aquifer, groundwater salinization is due to seawater intrusion and the saltwater is reaching an inland extent around 1.3 km from the shoreline. The contribution ratios of saline water bodies derived from the inverted chloride data vary for the oilfield brine from 1 to 13% and for the seawater from 2 to 21%.