title: Evaluation of factors influencing the groundwater chemistry in a small tropical island of Malaysia.
abstract: Groundwater chemistry of small tropical islands is influenced by many factors, such as recharge, weathering and seawater intrusion, among others, which interact with each other in a very complex way. In this work, multivariate statistical analysis was used to evaluate the factors controlling the groundwater chemistry of Kapas Island (Malaysia). Principal component analysis (PCA) was applied to 17 hydrochemical parameters from 108 groundwater samples obtained from 18 sampling sites. PCA extracted four PCs, namely seawater intrusion, redox reaction, anthropogenic pollution and weather factors, which collectively were responsible for more than 87% of the total variance of the island's hydrochemistry. The cluster analysis indicated that three factors (weather, redox reaction and seawater intrusion) controlled the hydrochemistry of the area, and the variables were allocated to three groups based on similarity. A Piper diagram classified the island's water types into Ca-HCO3 water type, Na-HCO3 water type, Na-SO4-Cl water type and Na-Cl water type, indicating recharge, mixed, weathering and leached from sewage and seawater intrusion, respectively. This work will provide policy makers and land managers with knowledge of the precise water quality problems affecting the island and can also serve as a guide for hydrochemistry assessments of other islands that share similar characteristics with the island in question.
authors: Faculty of Environmental Studies, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. nuraumar@gmail.com
authors: Nura Umar
authors: NU
authors: Kura
authors: Mohammad Firuz
authors: MF
authors: Ramli
authors: Wan Nur Azmin
authors: WN
authors: Sulaiman
authors: Shaharin
authors: S
authors: Ibrahim
authors: Ahmad Zaharin
authors: AZ
authors: Aris
authors: Adamu
authors: A
authors: Mustapha
mesh_terms: D016000:Cluster Analysis; D004784:Environmental Monitoring; D060587:Groundwater / Q000737:chemistry*; D008296:Malaysia; D015999:Multivariate Analysis; D010084:Oxidation-Reduction; D025341:Principal Component Analysis; D013054:Spectrophotometry, Atomic; D014874:Water Pollutants, Chemical / Q000032:analysis*; D060753:Water Quality; D014887:Weather
chemical_list: D014874:Water Pollutants, Chemical
references: Environ Monit Assess. 2013 Mar;185(3):2439-52
references: 22766921
references: Environ Int. 2009 Nov;35(8):1225-33
references: 19640587
references: Water Sci Technol. 2011;64(4):809-17
references: 22097065
references: Sci Total Environ. 2012 Oct 15;437:390-402
references: 22960402
references: Environ Sci Pollut Res Int. 2013 Apr;20(4):2421-34
references: 22935861
references: Environ Monit Assess. 2008 Mar;138(1-3):65-79
references: 17508262
references: Sci Total Environ. 2012 Nov 1;438:414-25
references: 23022725
references: BMC Public Health. 2007 Sep 21;7:256
references: 17888154
references: Int J Environ Res Public Health. 2011 Apr;8(4):1084-109
references: 21695030
references: Environ Monit Assess. 2010 May;164(1-4):297-310
references: 19396558
references: Environ Geochem Health. 2009 Dec;31(6):643-55
references: 19030998