Noorain Mohd Isa

Application of geoaccumulation index and enrichment factors on the assessment of heavy metal pollution in the sediments

An investigative study was carried out in Langat River to determine the heavy metal pollution in the sediment with 22 sampling stations selected for the collection of sediment samples. The sediment samples were digested and analyzed for extractable metal (48Cd, 29Cu, 30Zn, 33As, 82Pb) using the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Parameters, such as pH, Eh, electrical conductivity (EC), salinity, cation exchange capacity (CEC) and loss on ignition (LOI) were also determined. The assessment of heavy metal pollution was derived using the enrichment factors (EF) and geoaccumulation index (Igeo). This study revealed that the sediment is predominantly by As > Cd > Pb > Zn > Cu. As recorded the highest EF value at 187.45 followed by Cd (100.59), Pb (20.32), Zn (12.42) and Cu (3.46). This is similar to the Igeo, which indicates that the highest level goes to As (2.2), exhibits moderately polluted. Meanwhile, Cd recorded 1.8 and Pb (0.23), which illustrates that both of these elements vary from unpolluted to moderately polluted. The Cu and Zn levels are below 0, which demonstrates background concentrations. The findings are expected to update the current status of the heavy metal pollution as well as creating awareness concerning the security of the river water as a drinking water source.

Extent and severity of groundwater contamination based on hydrochemistry mechanism of sandy tropical coastal aquifer.

Small islands are susceptible to anthropogenic and natural activities, especially in respect of their freshwater supply. The freshwater supply in small islands may be threatened by the encroachment of seawater into freshwater aquifers, usually caused by over pumping. This study focused on the hydrochemistry of the Kapas Island aquifer, which controls the groundwater composition. Groundwater samples were taken from six constructed boreholes for the analysis and measurement of its in-situ and major ions. The experimental results show a positive and significant correlation between Na-Cl (r=0.907; p<0.01), which can be defined as the effect of salinization. The mechanisms involved in groundwater chemistry changes were ion exchange and mineralization. These processes can be demonstrated using Pipers diagram in which the water type has shifted into a Na-HCO(3) water type from a Ca-HCO(3) water type. Saturation indices have been calculated in order to determine the saturation condition related to dissolution or the precipitation state of the aquifer bedrock. About 76% of collected data (n=108) were found to be in the dissolution process of carbonate minerals. Moreover, the correlation between total CEC and Ca shows a positive and strong relationship (r=0.995; p<0.01). This indicates that the major mineral component in Kapas Island is Ca ion, which contributes to the groundwater chemical composition. The output of this research explains the chemical mechanism attributed to the groundwater condition of the Kapas Island aquifer.

Application of Environmetric Methods to Surface Water Quality Assessment of Langkawi Geopark (Malaysia)

Cluster analysis (CA), discriminant analysis (DA) and principal component analysis (PCA) were applied to evaluate the spatial variation in the river water quality data matrix of Langkawi Geopark. The CA result rendered two groups based on their similar properties. Group 1 comprised the sampling sites LG1, LG2, LG3, LG4, LG5, LG6, LG7, LG9, LG10, LG11, LG13, and LG14; Group 2 was further divided into two groups: Group 2(i) consisted of LG8, LG15, LG17, and LG19 while Group 2(ii) consisted of LG12, LG16, and LG18. DA revealed that COD, Cr and SO4 were the most significant parameters for discrimination between Group 1 and Group 2. The PCA results extracted seven components for Group 1 and six components for Group 2. Agriculture and sand mining were identified as the main latent pollution sources contributing to Group 1, while recreational activities constituted the major pollution source contributing to Group 2. This study illustrates the usefulness of environmetric techniques in the interpretation of complex data, optimizing monitoring networks to a lower cost mentoring program and controlling the degradation of surface water quality in Langkawi Geopark.

Applying the scores of multivariate statistical analyses to characterize the relationships between the hydrochemical properties and groundwater conditions in respect of the monsoon variation in Kapas Island, Terengganu, Malaysia

Abstract The different factors (seasonal changes) and variables (physicochemical) controlling the groundwater hydrochemistry of Kapas Island were identified using multivariate techniques principal component analysis (PCA), discriminant analysis (DA) and hierarchy cluster analysis (HCA). In the present study, the hydrochemistry of 216 groundwater samples, consisting of information concerning the in situ parameters and major ions in six monitoring boreholes, was studied and compared in two different monsoon seasons. The dominant variables derived from four components by PCA in the pre-monsoon indicated the influence of the salinity process, while the dominant variables derived from three components in the post-monsoon mostly indicated on the mineralization process. The DA gave the final variables after discriminating the insignificant variables based on the pre- and post-monsoon classifications. This provided important data reduction in terms of the mineralization process, as it only discriminated physical variables (TDS, EC, salinity, DO and temperature). Based on the HCA result, samples belonging to stations KW 3 and KW 4 were under Ca-rich water, while the remaining boreholes were grouped in Na-rich water.

Groundwater Composition and Geochemical Controls in Small Tropical Islands of Malaysia: A Comparative Study

Water usage for domestic and irrigation purposes differ greatly from country to country. Roughly, water use per capita increases with the increase of gross national income per capita. As speaking on national incomes, ecotourism activities in tropical countries play an important role in this field. Authorities on finance management focus on small islands as their greater contribution in ecotourism activities. Maintenance of small island ecology especially on groundwater has to be considered otherwise it hinders the growth of ecotourism development when it comes to overexploitation. Kapas Island and Manukan Island in Malaysia are among the islands that are highly developed for the ecotourism. Hence, unintentionally the groundwater in small islands is exposed to natural and manmade interference. A comparative study of these islands was done to clarify the sources of interference in the groundwater aquifer. An attempt to identify the hydrogeochemical processes in these small islands that accompany with current and past intrusion of seawater was made using the analyses on groundwater chemistry, saturation indices and ionic ratios. In addition of the major chemical compositions, analyses gives two different types of water, saturation index also indicates two different processes (saturation and dissolution) happened in the islands. Manukan Island tends to have Na-Cl water type and most of the groundwater samples were in precipitation condition with respect to carbonate minerals. Disparate to Kapas Island, it has Ca-HCO3 water type and experienced dissolution process in most groundwater samples. The results using ionic ratios were demonstrated to delineate the seawater intrusion process, which includes of Mg/Ca, Na/Cl, Na/K, SO4/Cl, Cl/HCO3 and Ca/(HCO3 + SO4). Comparison of ions derivation also shows two different major groups representing the islands. Other processes that related in this study were the ions exchanges and mineralization.

Application of Geochemical and Geostatistical Analyses in Observing the Controlling Factors of Groundwater Compositions

The groundwater hydrogeochemistry assessment has been carried out based on physic–chemical parameters (which are in situ and major ions) to observe the hydrochemical mechanism that might occur and control the groundwater chemistry changes. A total of 216 groundwater samples from Kapas Island were collected bimonthly during two different monsoon seasons which were South–West Monsoon known as pre-monsoon (August–October 2010) and North–East Monsoon known as post-monsoon (February–April 2011). Geochemical data on dissolved major constituents in groundwater samples from the Kapas Island revealed the main processes responsible for their hydrogeochemical evolution. The abundance of major ions revealed Ca > Na > Mg > K and HCO3 > Cl > SO4 dominations. Principal Component Analysis (PCA) extracts four (pre-monsoon) and three (post-monsoon) effective components which explained the origin of groundwater sources which have 81.6 and 78.9 % of total variances respectively. Comprised of variables TDS, EC, Salinity, Eh, pH, Cl, and Na in component 1, pre-monsoon experienced slightly saline process while component 1 in post-monsoon consist of Mg, TDS, EC, Salinity, Ca, Na, pH, Eh and HCO3 described the mineralization process of the geological matrix have taken place. Saturation indices of carbonate minerals were calculated using PHREEQC for window software; calcite, dolomite and aragonite solubility showed strong and positive correlationship value (p < 0.01) with Ca constituent respectively, also indicating mineralization processes.