Coastal aquifer groundwater is vulnerable to saltwater contamination as it is located near the coastline. Therefore, a study is conducted to confirm all the major source of pollutants on coastal groundwater based on 13 sampling wells that located close to Terengganu coastline as well as to assess the intensity of saltwater intrusion into the wells. Measurements of selected water quality parameters such as dissolve oxygen (DO), electrical conductivity (EC), total dissolve solid (TDS), salinity, pH, turbidity and total suspended solid (TSS) were obtained from each well by using certified scientific instruments. Data were analysed by using multivariate techniques which involves principle component analysis (PCA) and cluster analysis (CA). CA was performed by using hierarchical agglomerative cluster analysis (HACA) technique. PCA yielded two PCs where PC1 forms composite factor loadings of TDS, salinity and EC that represented the saltwater intrusion meanwhile, PC2 formed composite factors of turbidity, TSS and TDS that represented the anthropogenic pollutions. CA successfully classified sampling wells into seven clusters; Extreme High (EH), Very High (VH), High (H), Moderate (M), Low (L), Very Low (VL) and Extreme Low (EL) where each cluster represented the saltwater intrusion intensity in decreasing order.
Keywords: groundwater, coastal aquifer, saltwater intrusion, multivariate techniques
AbstrakAir bawah tanah dari akuifer pantai terdedah kepada pencemaran air masin kerana ia terletak berhampiran pantai. Oleh itu, satu kajian dijalankan untuk mengesahkan sumber utama pencemaran kepada air bawah tanah pantai berdasarkan 13 telaga pensampelan yang terletak berhampiran kawasan pantai Terengganu serta untuk menilai keamatan pencerobohan air masin ke dalam telaga.Pengukuran parameter kualiti air seperti oksigen terlarut (DO), kekonduksian elektrik (EC), jumlah pepejal terlarut (TDS), kemasinan, pH, kekeruhan dan jumlah pepejal terampai (TSS) diambil dari setiap telaga dengan menggunakan peralatan saintifik. Data dianalisis menggunakan teknik multivariat iaitu analisis komponen utama (PCA) dan analisis kelompok (CA). CA dilakukan menggunakan teknik analisis kelompok hierarki agglomeratif (HACA). PCA menghasilkan dua PC yang mana, PC1 membentuk faktor komposit TDS, kemasinan dan EC yang mewakili pencerobohan air masin manakala, PC2 membentuk faktor komposit kekeruhan, TSS dan TDS yang mewakili pencemaran antropogenik. CA berjaya mengelaskan telaga pensampelan kepada tujuh kelompok; Tinggi Ekstrem (EH), Sangat Tinggi (VH), Tinggi (H), Sederhana (M), Rendah (L), Sangat Rendah (VL) dan Rendah Ekstrem (EL) yang mana setiap kelompok mewakili keamatan pencerobohan air masin dalam urutan berkurangan.