Hydrogeochemical investigations had been carried out at the Amol-Babol Plain in the north of Iran. Geochemical processes and factors controlling the groundwater chemistry are identified based on the combination of classic geochemical methods with geographic information system (GIS) and geostatistical techniques. The results of the ionic ratios and Gibbs plots show that water rock interaction mechanisms, followed by cation exchange, and dissolution of carbonate and silicate minerals have influenced the groundwater chemistry in the study area. The hydrogeochemical characteristics of groundwater show a shift from low mineralized Ca-HCO3, Ca-Na-HCO3, and Ca-Cl water types to high mineralized Na-Cl water type. Three classes, namely, C1, C2, and C3, have been classified using cluster analysis. The spatial distribution maps of Na(+)/Cl(-), Mg(2+)/Ca(2+), and Cl(-)/HCO3 (-) ratios and electrical conductivity values indicate that the carbonate and weathering of silicate minerals played a significant role in the groundwater chemistry on the southern and western sides of the plain. However, salinization process had increased due to the influence of the evaporation-precipitation process towards the north-eastern side of the study area.
A short-term investigation on the chemical composition of rainwater was carried out at five selected sampling stations in Kuantan district, Pahang, Malaysia. Sampling of rainwater was conducted by event basis between September and November 2011. Rainwater samples were collected using polyethylene containers and the parameters measured were cations (sodium, potassium, ammonium, calcium and magnesium) and anions (chlorides, nitrates and sulphates). The average pH value for rainwater samples was 6.0 ± 0.57 in which most of the sampling sites exhibited pH values >5.6. Calcium and sulphate were the most abundant cation and anion, respectively, whilst the concentrations of other major ions varied according to sampling location.
In this paper, numerous studies on groundwater in Malaysia were reviewed with the aim of evaluating past trends and the current status for discerning the sustainability of the water resources in the country. It was found that most of the previous groundwater studies (44 %) focused on the islands and mostly concentrated on qualitative assessment with more emphasis being placed on seawater intrusion studies. This was then followed by inland-based studies, with Selangor state leading the studies which reflected the current water challenges facing the state. From a methodological perspective, geophysics, graphical methods, and statistical analysis are the dominant techniques (38, 25, and 25 %) respectively. The geophysical methods especially the 2D resistivity method cut across many subjects such as seawater intrusion studies, quantitative assessment, and hydraulic parameters estimation. The statistical techniques used include multivariate statistical analysis techniques and ANOVA among others, most of which are quality related studies using major ions, in situ parameters, and heavy metals. Conversely, numerical techniques like MODFLOW were somewhat less admired which is likely due to their complexity in nature and high data demand. This work will facilitate researchers in identifying the specific areas which need improvement and focus, while, at the same time, provide policymakers and managers with an executive summary and knowledge of the current situation in groundwater studies and where more work needs to be done for sustainable development.
A new cobalt(II) ion selective electrode based on palladium(II) dichloro acetylthiophene fenchone azine(I) has been developed. The best membrane composition is found to be 10:60:10:21.1 (I)/PVC/NaTPB/DOP (w/w). The electrode exhibits a Nerstian response in the range of 1.0 × 10(-1)-1.0 × 10(-6)M with a detection limit and slope of 8.0 × 10(-7)M and 29.6 ± 0.2 mV per decade respectively. The response time is within the range of 20-25s and can be used for a period of up to 4 months. The electrode developed reveals good selectivity for cobalt(II) and could be used in pH range of 3-7. The electrode has been successfully used in the determination of cobalt(II) in water samples.
It is important to assess indoor air quality in school classrooms where the air quality may significantly influence school children's health and performance. This study aims to determine the concentrations of PM2.5 and dust chemical compositions in indoor and outdoor school classroom located in Kuala Lumpur City Centre. The PM2.5 concentration was measured from 19th September 2017-16th February 2018 using an optical PM2.5 sensor. Indoor and outdoor dust was also collected from the school classrooms and ion and trace metal concentrations were analysed using ion chromatography (IC) and inductively couple plasma-mass spectrometry (ICP-MS) respectively. This study showed that the average indoor and outdoor 24 h PM2.5 was 11.2 ± 0.45 µg m-3 and 11.4 ± 0.44 µg m-3 respectively. The 8 h PM2.5 concentration ranged between 3.2 and 28 µg m-3 for indoor and 3.2 and 19 µg m-3 for outdoor classrooms. The highest ion concentration in indoor dust was Ca2+ with an average concentration of 38.5 ± 35.0 µg g-1 while for outdoor dust SO42- recorded the highest ion concentration with an average concentration of 30.6 ± 9.37 µg g-1. Dominant trace metals in both indoor and outdoor dust were Al, Fe and Zn. Principle component analysis-multiple linear regression (PCA-MLR) demonstrated that the major source of indoor dust was road dust (69%), while soil dominated the outdoor dust (74%). Health risk assessment showed that the hazard quotient (HQ) value for non-carcinogenic trace metals was
Microbes in groundwater play a key role in determining the drinking water quality of the water. The study aims to interpret the sources of microbes in groundwater and its relationship to geochemistry. The study was carried out by collecting groundwater samples and analyzed to obtain various cations and anions, where HCO3-, Cl- and NO3- found to be higher than permissible limits in few samples. Microbial analysis, like total coliform (TC), total viable counts (TVC), fecal coliforms (FC), Vibrio cholera (V. cholerae) and total Streptococci (T. streptococci) were analyzed, and the observations reveal that most of the samples were found to be above the permissible limits adopted by EU, BIS, WHO and USEPA standards. Correlation analysis shows good correlation between Mg2+-HCO3-, K+-NO3-, TVC- V. cholerae and T. streptococci-FC. Major ions like Mg+, K+, NO3, Ca2+ and PO4 along with TS and FC were identified to control the geochemical and microbial activities in the region. The magnesium hardness in the groundwater is inferred to influence the TVC and V. cholerae. The mixing of effluents from different sources reflected the association of Cl with TC. Population of microbes T. streptococci and FC was mainly associated with Ca and Cl content in groundwater, depicting the role of electron acceptors and donors. The sources of the microbial population were observed with respect to the land use pattern and the spatial distribution of hydrogeochemical factors in the region. The study inferred that highest microbial activity in the observed in the residential areas, cultivated regions and around the landfill sites due to the leaching of sewage water and fertilizers runoff into groundwater. The concentrations of ions and microbes were found to be above the permissible limits of drinking water quality standards. This may lead to the deterioration in the health of particular coastal region.
In this study, geophysics, geochemistry, and geostatistical techniques were integrated to assess seawater intrusion in Kapas Island due to its geological complexity and multiple contamination sources. Five resistivity profiles were measured using an electric resistivity technique. The results reveal very low resistivity <1 Ωm, suggesting either marine clay deposit or seawater intrusion or both along the majority of the resistivity images. As a result, geochemistry was further employed to verify the resistivity evidence. The Chadha and Stiff diagrams classify the island groundwater into Ca-HCO3, Ca-Na-HCO3, Na-HCO3, and Na-Cl water types, with Ca-HCO3 as the dominant. The Mg(2+)/Mg(2+)+Ca(2+), HCO3 (-)/anion, Cl(-)/HCO3 (-), Na(+)/Cl(-), and SO4 (2-)/Cl(-) ratios show that some sampling sites are affected by seawater intrusion; these sampling sites fall within the same areas that show low-resistivity values. The resulting ratios and resistivity values were then used in the geographical information system (GIS) environment to create the geostatistical map of individual indicators. These maps were then overlaid to create the final map showing seawater-affected areas. The final map successfully delineates the area that is actually undergoing seawater intrusion. The proposed technique is not area specific, and hence, it can work in any place with similar completed characteristics or under the influence of multiple contaminants so as to distinguish the area that is truly affected by any targeted pollutants from the rest. This information would provide managers and policy makers with the knowledge of the current situation and will serve as a guide and standard in water research for sustainable management plan.
Aluminium (Al) phytotoxicity is an important soil constraint that limits crop yield. The objectives of this study were to investigate how growth, physiology, nutrient content and organic acid concentration is affected by Al, and to assess the degree of Al tolerance in different oil palm progeny (OPP). Four OPPs ['A' (Angola dura × Angola dura), 'B' (Nigerian dura × Nigerian dura), 'C' (Deli dura × AVROS pisifera) and 'D' (Deli dura × Dumpy AVROS pisifera)] were grown in different Al concentrations (0, 100 and 200 μm) in aerated Hoagland solution, pH 4.4, for 80 days. We observed a severe reduction (57.5%) in shoot dry weight, and root tips were reduced by 46.5% in 200 μm Al. In 'B' and 'C', the majority of macro- and micronutrients in plants were reduced significantly by 200 μm Al, with Mg being lowered by more than 50% in roots and shoots. The 200 μm Al treatment resulted in a 56.50% reduction in total leaf area, a 20% reduction in net photosynthesis and a 17% reduction in SPAD chlorophyll value in the third leaf. Root tips (0-5 mm) showed a significant increase in oxalic acid content with increasing Al concentration (∼ 5.86-fold); progeny 'A' had the highest concentration of oxalic acid. There was a significant interaction between Al concentration × OPP on total leaf number, root volume, lateral root length, Mg and K in root and shoot tissues, and Ca and N in shoots. The OPPs could be ranked in their tolerance to Al as: 'A' > 'D' > 'B' > 'C'.