Geological mapping in Kuala Betis Area, Gua Musang and seawater intrusion studies in Pengkalan Chepa using geophysical and geochemical method

Generally seawater intrusion is a natural process but this process can be exacerbated by human activities. Human activities such as over-exploitation of groundwater can be one of the reason of sea water intrusion. Seawater intrusion can affect the quality and quantity of fresh groundwater in shallow aquifers as seawater is one of contamination source for groundwater. Therefore, this research is important to identify the extent of seawater intrusion in Pengkalan Chepa using Electrical Resistivity Imaging (ERI) and analyse the quality of coastal groundwater in Pengkalan Chepa using in-situ physical parameter. Electrical Resistivity Imaging (ERI) method used by using ABEM Terrameter LS instrument to produce a 2D pseudosection imaging of the subsurface to distinguish the seawater-freshwater interface with configurations used such as Wenner-Schlumberger and Pole-dipole array. The result display the extension of seawater intrusion from the shoreline. Integrated together with in-situ multiparameter, the parameters such as pH, temperature, salinity, turbidity, Total Dissolved Solids (TDS), Total Suspended Solids (TSS), and Electrical Conductivity were assessed. Using collected water samples, it is analysed using Atomic Absorption Spectroscopy (AAS) to measure the concentration of trace elements such as copper (Cu), manganese (Mn), potassium (K), sodium (Na) and Iron (Fe). The results then correlated with the National Guideline of Groundwater Quality Standards by Department of Environment. Latest geological map of Kuala Betis area, Gua Musang was produced by using ArcGIS software based on geological data during geological mapping.