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  1. Growth and production of biomass of Rhodovulum sulfidophilum in sardine processing wastewater
    Azad SA, Vikineswary S, Ramachandran KB, Chong VC
    Lett Appl Microbiol, 2001 Oct;33(4):264-8.
    PMID: 11559398
    AIMS: Rhodovulum sulfidophilum was grown in sardine processing wastewater to assess growth characteristics for the production of bacterial biomass with simultaneous reduction of chemical oxygen demand.

    METHODS AND RESULTS: Growth characteristics were compared in diluted and undiluted, settled and non-settled wastewater growing in anaerobic light and aerobic dark conditions; and also at different agitation speeds. The highest biomass (8.75 g l(-1)) and a reduction in chemical oxygen demand of 71% were obtained in unsettled, undiluted wastewater after 120 h culture with 15% inoculum. In settled wastewater, highest biomass (7.64 g l(-1)) and a COD reduction of 77% was also obtained after 120 h. Total biomass was higher (4.34 g l(-1)) after 120 h culture in anaerobic light compared to (3.23 g l(-1)) in aerobic dark growth.

    CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: Better performance, mean of total biomass (6.97 g l(-1) after 96 h), total carotenoids (4.24 mg g(-1) dry cell from 24 h) and soluble protein (431 microg ml(-1) after 96 h) were obtained from aerobic dark culture at 300 rev min(-1). The COD reduction, however, was lower (69%) after 96 h culture. Thus, the benefits in the production of bacterial biomass in non-sterilized sardine processing wastewater with the reduction of chemical oxygen demand could be achieved.

    Matched MeSH terms: Water Microbiology*; Water Pollution*
  2. Occurrence of Heavy Metals in Groundwater Along the Lithological Interface of K/T Boundary, Peninsular India: A Special Focus on Source, Geochemical Mobility and Health Risk
    Chandrasekar T, Keesari T, Gopalakrishnan G, Karuppannan S, Senapathi V, Sabarathinam C, et al.
    Arch Environ Contam Toxicol, 2021 Jan;80(1):183-207.
    PMID: 33392777 DOI: 10.1007/s00244-020-00803-1
    Evaluation of the hydrogeochemical processes governing the heavy metal distribution and the associated health risk is important in managing and protecting the health of freshwater resources. This study mainly focused on the health impacts due to the heavy metals pollution in a known Cretaceous-Tertiary (K/T) contact region (Tiruchinopoly, Tamilnadu) of peninsular India, using various pollution indices, statistical, and geochemical analyses. A total of 63 samples were collected from the hard rock aquifers and sedimentary formations during southwest monsoon and analysed for heavy metals, such as Li, Be, Al, Rb, Sr, Cs, Ba, pb, Mn, Fe, Cr, Zn, Ga, Cu, As, Ni, and Co. Ba was the dominant element that ranged from 441 to 42,638 μg/l in hard rock aquifers, whereas Zn was the major element in sedimentary formations, with concentrations that ranged from 44 to 118,281 μg/l. The concentrations of Fe, Ni, Cr, Al, Cr, and Ni fell above the permissible limit in both of the formations. However, the calculated heavy metal evaluation index (HEI), heavy metal pollution index (HPI), and the degree of contamination (Cd) parameters were higher in the sedimentary formation along the contact zone of the K/T boundary. Excessive health risks from consumption of contaminated groundwater were mostly confined to populations in the northern and southwestern regions of the study area. Carcinogenic risk assessment suggests that there are elevated risks of cancer due to prolonged consumption of untreated groundwater. Ba, Sr, and Zn were found to be geochemically highly mobile due to the partitioning between the rock matrix and groundwater, aided by the formation of soluble carbonato-complexes. Factor analysis indicates that the metals are mainly derived from the host rocks and anthropogenic inputs are relatively insignificant. Overall, this study indicated that groundwater in K/T contact zones is vulnerable to contamination because of the favorable geochemical factors. Long-term monitoring of such contact zones is required to avert the potential health hazards associated with consumption of the contaminated groundwater.
    Matched MeSH terms: Fresh Water/chemistry; Water Pollutants, Chemical/analysis*
  3. Fulltext Accumulation and risk assessment of heavy metals employing species sensitivity distributions in Linggi River, Negeri Sembilan, Malaysia
    Razak MR, Aris AZ, Zakaria NAC, Wee SY, Ismail NAH
    Ecotoxicol Environ Saf, 2021 Mar 15;211:111905.
    PMID: 33453636 DOI: 10.1016/j.ecoenv.2021.111905
    The constant increase of heavy metals into the aqueous environment has become a contemporary global issue of concern to government authorities and the public. The study assesses the concentration, distribution, and risk assessment of heavy metals in freshwater from the Linggi River, Negeri Sembilan, Malaysia. Species sensitivity distribution (SSD) was utilised to calculate the cumulative probability distribution of toxicity from heavy metals. The aquatic organism's toxicity data obtained from the ECOTOXicology knowledgebase (ECOTOX) was used to estimate the predictive non-effects concentration (PNEC). The decreasing sequence of hazardous concentration (HC5) was manganese > aluminium > copper > lead > arsenic > cadmium > nickel > zinc > selenium, respectively. The highest heavy metal concentration was iron with a mean value of 45.77 μg L-1, followed by manganese (14.41 μg L-1) and aluminium (11.72 μg L-1). The mean heavy metal pollution index (HPI) value in this study is 11.52, implying low-level heavy metal pollutions in Linggi River. The risk quotient (RQ) approaches were applied to assess the potential risk of heavy metals. The RQ shows a medium risk of aluminium (RQm = 0.1125) and zinc (RQm = 0.1262); a low risk of arsenic (RQm = 0.0122) and manganese (RQm = 0.0687); and a negligible risk of cadmium (RQm = 0.0085), copper (RQm = 0.0054), nickel (RQm = 0.0054), lead (RQm = 0.0016) and selenium (RQm = 0.0012). The output of this study produces comprehensive pollution risk, thus provides insights for the legislators regarding exposure management and mitigation.
    Matched MeSH terms: Fresh Water; Water Pollutants, Chemical/analysis; Water Pollutants, Chemical/toxicity*
  4. Fulltext An Extended Thickness-Dependent Moisture Absorption Model for Unidirectional Carbon/Epoxy Composites
    Azizan A, Johar M, Karam Singh SS, Abdullah S, Koloor SSR, Petrů M, et al.
    Polymers (Basel), 2021 Jan 30;13(3).
    PMID: 33573112 DOI: 10.3390/polym13030440
    Moisture absorption tests for materials that exhibit non-Fickian behavior generally require a relatively long period to reach saturation. Therefore, it would be beneficial to establish a relationship between the moisture content and the thickness to minimize the experimental time and cost. This research characterizes the moisture absorption behavior of AS4/8552 carbon/epoxy composites. Specimens were prepared at 4, 8, and 16 plies and immersed in distilled water at 60 °C. The relationship between the non-Fickian parameters (Fickian to non-Fickian maximum moisture content ratio ϕ, non-Fickian diffusivity per square thickness α, and non-Fickian initiation time to) and thickness was characterized using a thickness-dependent model. A comparison with other materials revealed that all three non-Fickian parameters are able to be fitted using a power law. Nevertheless, the upper boundary for the applicability of this model was not determined in this study. The Weibull distribution plots indicate that the probability of non-Fickian moisture absorption is influenced by ϕ and α at approximately 62% within a normalized thickness range of 2-3. In regards to to, it is 82% at a normalized thickness of 6. Therefore, the Weibull distribution is proposed for the assessment of non-Fickian moisture absorption based on the material's thickness.
    Matched MeSH terms: Water
  5. Fulltext A case of unrecognized psychogenic polydipsia
    Seng-Choi Chong, Normala Ibrahim
    Malaysian Journal of Medicine and Health Sciences, 2020;16(3):337-339.
    MyJurnal
    Psychogenic polydipsia is prevalent among people with schizophrenia. Although its pathophysiology is relatively unknown, it causes life threatening complications due to acute or severe hyponatraemia.. This report illustrates a patient with schizophrenia who had unrecognized psychogenic polydipsia and developed severe complication. It also highlights the clinical salience of its management.
    Matched MeSH terms: Water Intoxication
  6. Fulltext Mesoporous Carbon: A Versatile Material for Scientific Applications
    Rahman MM, Ara MG, Alim MA, Uddin MS, Najda A, Albadrani GM, et al.
    Int J Mol Sci, 2021 Apr 26;22(9).
    PMID: 33925852 DOI: 10.3390/ijms22094498
    Mesoporous carbon is a promising material having multiple applications. It can act as a catalytic support and can be used in energy storage devices. Moreover, mesoporous carbon controls body's oral drug delivery system and adsorb poisonous metal from water and various other molecules from an aqueous solution. The accuracy and improved activity of the carbon materials depend on some parameters. The recent breakthrough in the synthesis of mesoporous carbon, with high surface area, large pore-volume, and good thermostability, improves its activity manifold in performing functions. Considering the promising application of mesoporous carbon, it should be broadly illustrated in the literature. This review summarizes the potential application of mesoporous carbon in many scientific disciplines. Moreover, the outlook for further improvement of mesoporous carbon has been demonstrated in detail. Hopefully, it would act as a reference guidebook for researchers about the putative application of mesoporous carbon in multidimensional fields.
    Matched MeSH terms: Water Purification
  7. Fulltext THE EFFECTIVENESS OF ADSORBENT DERIVED FROM MORINGA OLEIFERA AS A WATER TREATMENT AGENT
    Farasyahida A. Samad, Wan Salida Wan Mansor, idayatul Aini Zakaria
    UMT Journal of Undergraduate Research, 2019;1(4):51-60.
    MyJurnal
    Clean, safe and readily available water is very crucial in everyday life, especially for health, hygiene, and the productivity of the community. Unfortunately, increase in contaminants in water supplies from human activities and industrialization is very worrying. Conventional wastewater treatment includes the usage of alum that will affect health with prolonged consumption. This research was carried out to focus on the development of wastewater treatment system using adsorbent from Moringa oleifera seeds. Adsorbent was successfully synthesized from the seeds of Moringa oleifera. Characterization of the sample was made using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), while the effectiveness of water treatment was analyzed using Turbidity Meter. Then, all samples were tested against kaolin wastewater. XRD results showed that all the adsorbent samples were amorphous in nature. FTIR results indicated that there were hydroxyl group and carboxylic group in the sample representing numerous oxygen-riddled functional groups on the surface. From SEM results, it was clearly shown that the pore structure and size of Moringa oleifera affected the capability of adsorption where the smaller the size, the more effective the sample. Turbidity test showed that the sample that worked best for wastewater treatment was adsorbent from Moringa oleifera seeds in size of 125µm that was heated for 4 hours with 93.76% turbidity removal. Therefore, this study proved that the adsorbent from Moringa oleifera seeds is very suitable for high turbidity wastewater treatment. Further studies investigating the combination of conventional activated carbon with adsorbent from Moringa oleifera seeds should be conducted before these samples are made available for further use so that we can compare which sample works best for wastewater treatment.
    Matched MeSH terms: Water; Water Supply; Water Purification; Waste Water
  8. Fulltext DISTRIBUTION AND DIVERSITY OF FORAMINIFERA IN THE NORTHWEST OF SARAWAK OFFSHORE WATERS, MALAYSIA
    WAN NUR SYARAH WAN MUHAMED SABRI, OMAR ABDULA RAHMAN ABDUL MANAF, FATIN IZZATI MINHAT, FATIN IZZATI MINHAT
    UMT Journal of Undergraduate Research, 2019;1(2):19-25.
    MyJurnal
    A study on distribution and diversity of benthic foraminifera in surface sediments was carried out in Northwestern Sarawak waters, Malaysia. The range of water depth at the study site was between 43 m and 71 m. A total of seven sediment samples were taken for this study. As a result, 11 genera were identified from a total of 1,222 individuals of foraminifera. 200 individuals were picked out from each sample. The 11 genera that were identified from the study site included Heterolepaspp., Textulariaspp., Quinqueloculinaspp.,Operculina spp. Pseudorotaliaspp., Amphisteginaspp., Cylindroclavulinaspp., Elphidiumspp., Ammobaculitesspp., Asterorotaliaspp. and Bolivinaspp.. The common genera found in the sediments of the study areas were Heterolepa, Textularia, Quincoloculina, Operculinaand Pseudorotalia. The highest and lowest values of Fisher alpha and Shannon-Wiener indices were shown at Station C287 and Station B482 respectively. The highest value of Fisher alpha was 3.23 and the lowest value was 1.97. The highest and lowest values of Shannon-Wiener were 2.30 and 1.91. The highest index value of diversity was 3.23 at depth 67.76 m and the lowest value was 1.53 at depth 45.54 m and 68.45 m. From this study, depth is not the main factor that influencesthe diversity of benthic foraminiferal in northwestern Sarawak waters.
    Matched MeSH terms: Water
  9. Recent advances in the removal of pharmaceuticals and endocrine-disrupting compounds in the aquatic system: A case of polymer inclusion membranes
    Olasupo A, Suah FBM
    J Hazard Mater, 2021 03 15;406:124317.
    PMID: 33307454 DOI: 10.1016/j.jhazmat.2020.124317
    The presence of pharmaceuticals and endocrine-disrupting compounds in aquatic systems is a matter of great concern. The occurrence, fate, and potential toxicity of these compounds have triggered the interest of the scientific community. As a result of their high solubility and low volatility, they are common in aquatic systems, and wastewater treatment plants (WWTP) are the main reservoir for these contaminants. Conventional WWTPs have demonstrated an inability to remove these contaminants completely; hence, different advanced treatment processes have been explored to compensate for the lapses of the conventional system. The outcome of this study revealed the significant improvements made using advanced treatment processes to diminish the number of contaminants; however, some contaminants have proven to be refractory. Thus, there is a need to modify various advanced treatment processes or employ additional treatment processes. Polymer inclusion membranes (PIMs) are a liquid membrane technology that is highly efficient at removing contaminants from water. They have been widely studied for the removal of heavy metals and nutrients from aquatic systems; however, only a few studies have investigated the use of PIMs to remove pharmaceutically active compounds from aquatic systems. This research aims to raise awareness on the application of PIMs as a promising water treatment technology which has a great potential for the remediation of pharmaceuticals and endocrine disruptors in the aquatic system, due to its versatility, ease/low cost of preparation and high contaminant selectivity.
    Matched MeSH terms: Waste Water
  10. Baseline distribution and sources of selected agricultural runoff in the bottom water of an active cockle farming area, Bagan Pasir, Perak, Malaysia
    Joni AAM, Mohamat-Yusuff F, Noor NAM, Mohamed KN, Ash'aari ZH, Kusin FM, et al.
    Mar Pollut Bull, 2021 Jun;167:112276.
    PMID: 33901978 DOI: 10.1016/j.marpolbul.2021.112276
    This paper aims to study the spatial and temporal patterns of selected agricultural runoff, specifically in terms of glyphosate, nitrate, and ammonia in bottom water, as well as their possible sources, within an active cockle farming area in Bagan Pasir, Perak, Malaysia. Samples were taken along the cockle farming area from March to November 2019. Glyphosate was analyzed using HPLC with both extraction and derivatization methods using 9-fluorenyl-methyl chloroformate (FMOC-Cl), while nitrate and ammonia levels were determined using the standard Hach method. Generally, glyphosate, nitrate, and ammonia were present within the study site with the average concentration of 37.44 ± 12.27 μg/l, 1.65 ± 0.52 mg/l, and 0.37 ± 0.19 mg/l, respectively. The results suggest that glyphosate and nitrate might be derived from an inland source, while a uniform and low level of ammonia suggested might originate from lithogenic origins. Continuous monitoring remains encouraged.
    Matched MeSH terms: Water
  11. Removal of protein wastes by cylinder-shaped NaY zeolite adsorbents decorated with heavy metal wastes
    Cheng TH, Sankaran R, Show PL, Ooi CW, Liu BL, Chai WS, et al.
    Int J Biol Macromol, 2021 Aug 31;185:761-772.
    PMID: 34216668 DOI: 10.1016/j.ijbiomac.2021.06.177
    Cylinder-shaped NaY zeolite was used as an adsorbent for eradicating both heavy metal ions (Cu2+, Zn2+, Ni2+, and Co2+) and proteins from the waste streams. As a pseudo-metal ion affinity adsorbent, NaY zeolite was used in the capture of heavy metal ions in the first stage. The amount (molar basis) of metal ions adsorbed onto NaY zeolite decreased in the order of Cu2+ > Zn2+ > Co2+ > Ni2+. Bovine serum albumin (BSA) was utilized as a model of proteins used in the waste adsorption process by NaY zeolite. The adsorption capacities of NaY zeolite and Cu/NaY zeolite for BSA were 14.90 mg BSA/g zeolite and 84.61 mg BSA/g zeolite, respectively. Moreover, Cu/NaY zeolite was highly stable in the solutions made of 2 M NaCl, 500 mM imidazole or 125 mM EDTA solutions. These conditions indicated that the minimal probability of secondary contamination caused by metal ions and soluble proteins in the waste stream. This study demonstrates the potential of Cu/NaY zeolite complex as an efficient pseudo-metal chelate adsorbent that could remove metal ions and water-soluble proteins from wastewater concurrently.
    Matched MeSH terms: Water Pollutants, Chemical/analysis*; Waste Water/chemistry
  12. In situ generation of plasma-activated aerosols via surface acoustic wave nebulization for portable spray-based surface bacterial inactivation
    Wong KS, Lim WTH, Ooi CW, Yeo LY, Tan MK
    Lab Chip, 2020 05 19;20(10):1856-1868.
    PMID: 32342089 DOI: 10.1039/d0lc00001a
    The presence of reactive species in plasma-activated water is known to induce oxidative stresses in bacterial species, which can result in their inactivation. By integrating a microfludic chipscale nebulizer driven by surface acoustic waves (SAWs) with a low-temperature atmospheric plasma source, we demonstrate an efficient technique for in situ production and application of plasma-activated aerosols for surface disinfection. Unlike bulk conventional systems wherein the water is separately batch-treated within a container, we show in this work the first demonstration of continuous plasma-treatment of water as it is transported through a paper strip from a reservoir onto the chipscale SAW device. The significantly larger surface area to volume ratio of the water within the paper strip leads to a significant reduction in the duration of the plasma-treatment, while maintaining the concentration of the reactive species. The subsequent nebulization of the plasma-activated water by the SAW then allows the generation of plasma-activated aerosols, which can be directly sprayed onto the contaminated surface, therefore eliminating the storage of the plasma-activated water and hence circumventing the typical limitation in conventional systems wherein the concentration of the reactive species diminishes over time during storage, resulting in a reduction in the efficacy of bacterial inactivation. In particular, we show up to 96% reduction in Escherichia coli colonies through direct spraying with the plasma-activated aerosols. This novel, low-cost, portable and energy-efficient hybrid system necessitates only minimal maintenance as it only requires the supply of tap water and battery power for operation, and is thus suitable for decontamination in home environments.
    Matched MeSH terms: Water
  13. Novel sequential flow baffled microalgal-bacterial photobioreactor for enhancing nitrogen assimilation into microalgal biomass whilst bioremediating nutrient-rich wastewater simultaneously
    Leong WH, Lim JW, Lam MK, Lam SM, Sin JC, Samson A
    J Hazard Mater, 2021 05 05;409:124455.
    PMID: 33168319 DOI: 10.1016/j.jhazmat.2020.124455
    A novel sequential flow baffled microalgal-bacterial (SFB-AlgalBac) photobioreactor was designed to cater for the synergistic interactions between microalgal and bacterial consortia to enhance nitrogen assimilation into microalgal biomass from nutrient-rich wastewater medium. The performance of the SFB-AlgalBac photobioreactor was found to be optimum at the influent flow rate of 5.0 L/d, equivalent to 20 days of hydraulic retention time (HRT). The highest microalgal nitrogen assimilation rate (0.0271 /d) and biomass productivity (1350 mg/d) were recorded amidst this flow rate. Further increase to the 10.0 L/d flow rate reduced the photobioreactor performance, as evidenced by a reduction in microalgal biomass productivity (>10%). The microalgal biomass per unit of nitrogen assimilated values were attained at 16.69 mg/mg for the 5.0 L/d flow rate as opposed to 7.73 mg/mg for the 10.0 L/d flow rate, despite both having comparable specific growth rates. Also, the prior influent treatment by activated sludge was found to exude extracellular polymeric substances which significantly improved the microalgal biomass settleability up to 37%. The employment of SFB-AlgalBac photobioreactor is anticipated could exploit the low-cost nitrogen sources from nutrient-rich wastewaters via bioconversion into valuable microalgal biomass while fulfilling the requirements of sustainable wastewater treatment technologies.
    Matched MeSH terms: Waste Water
  14. Fulltext Optimal reduction of chemical oxygen demand and NH3-N from landfill leachate using a strongly resistant novel Bacillus salmalaya strain
    Dadrasnia A, Azirun MS, Ismail SB
    BMC Biotechnol, 2017 Nov 28;17(1):85.
    PMID: 29179747 DOI: 10.1186/s12896-017-0395-9
    BACKGROUND: When the unavoidable waste generation is considered as damaging to our environment, it becomes crucial to develop a sustainable technology to remediate the pollutant source towards an environmental protection and safety. The development of a bioengineering technology for highly efficient pollutant removal is this regard. Given the high ammonia nitrogen content and chemical oxygen demand of landfill leachate, Bacillus salmalaya strain 139SI, a novel resident strain microbe that can survive in high ammonia nitrogen concentrations, was investigated for the bioremoval of ammonia nitrogen from landfill leachate. The treatability of landfill leachate was evaluated under different treatment parameters, such as temperature, inoculum dosage, and pH.

    RESULTS: Results demonstrated that bioaugmentation with the novel strain can potentially improve the biodegradability of landfill leachate. B. salmalaya strain 139SI showed high potential to enhance biological treatment given its maximum NH3-N and COD removal efficiencies. The response surface plot pattern indicated that within 11 days and under optimum conditions (10% v/v inoculant, pH 6, and 35 °C), B. salmalaya strain139SI removed 78% of ammonia nitrogen. At the end of the study, biological and chemical oxygen demands remarkably decreased by 88% and 91.4%, respectively. Scanning electron microscopy images revealed that ammonia ions covered the cell surface of B. salmalaya strain139SI.

    CONCLUSIONS: Therefore, novel resistant Bacillus salmalaya strain139SI significantly reduces the chemical oxygen demand and NH3-N content of landfill leachate. Leachate treatment by B. salmalaya strain 139SI within 11 days.

    Matched MeSH terms: Water Pollutants, Chemical/analysis*; Water Pollutants, Chemical/metabolism; Water Pollutants, Chemical/chemistry
  15. A review on phytoremediation of contaminants in air, water and soil
    Wei Z, Van Le Q, Peng W, Yang Y, Yang H, Gu H, et al.
    J Hazard Mater, 2021 02 05;403:123658.
    PMID: 33264867 DOI: 10.1016/j.jhazmat.2020.123658
    There is a global need to use plants to restore the ecological environment. There is no systematic review of phytoremediation mechanisms and the parameters for environmental pollution. Here, we review this situation and describe the purification rate of different plants for different pollutants, as well as methods to improve the purification rate of plants. This is needed to promote the use of plants to restore the ecosystems and the environment. We found that plants mainly use their own metabolism including the interaction with microorganisms to repair their ecological environment. In the process of remediation, the purification factors of plants are affected by many conditions such as light intensity, stomatal conductance, temperature and microbial species. In addition the efficiency of phytoremediation is depending on the plants species-specific metabolism including air absorption and photosynthesis, diversity of soil microorganisms and heavy metal uptake. Although the use of nanomaterials and compost promote the restoration of plants to the environment, a high dose may have negative impacts on the plants. In order to improve the practicability of the phytoremediation on environmental restoration, further research is needed to study the effects of different kinds of catalysts on the efficiency of phytoremediation. Thus, the present review provides a recent update for development and applications of phytoremediation in different environments including air, water, and soil.
    Matched MeSH terms: Water
  16. Application of artificial intelligence methods for monsoonal river classification in Selangor river basin, Malaysia
    Wong YJ, Shimizu Y, Kamiya A, Maneechot L, Bharambe KP, Fong CS, et al.
    Environ Monit Assess, 2021 Jun 22;193(7):438.
    PMID: 34159431 DOI: 10.1007/s10661-021-09202-y
    Rivers in Malaysia are classified based on water quality index (WQI) that comprises of six parameters, namely, ammoniacal nitrogen (AN), biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), pH, and suspended solids (SS). Due to its tropical climate, the impact of seasonal monsoons on river quality is significant, with the increased occurrence of extreme precipitation events; however, there has been little discussion on the application of artificial intelligence models for monsoonal river classification. In light of these, this study had applied artificial neural network (ANN) and support vector machine (SVM) models for monsoonal (dry and wet seasons) river classification using three of the water quality parameters to minimise the cost of river monitoring and associated errors in WQI computation. A structured trial-and-error approach was applied on input parameter selection and hyperparameter optimisation for both models. Accuracy, sensitivity, and precision were selected as the performance criteria. For dry season, BOD-DO-pH was selected as the optimum input combination by both ANN and SVM models, with testing accuracy of 88.7% and 82.1%, respectively. As for wet season, the optimum input combinations of ANN and SVM models were BOD-pH-SS and BOD-DO-pH with testing accuracy of 89.5% and 88.0%, respectively. As a result, both optimised ANN and SVM models have proven their prediction capacities for river classification, which may be deployed as effective and reliable tools in tropical regions. Notably, better learning and higher capacity of the ANN model for dataset characteristics extraction generated better predictability and generalisability than SVM model under imbalanced dataset.
    Matched MeSH terms: Water Quality
  17. Fulltext The effects of ground water level fluctuation on slope stability by using Slopew
    Jestin Jelani, Nur Amirah Adnan, Hapsa Husen, Mohd Nazrin Mohd Daud, Suriyadi Sojipto
    ZULFAQAR International Journal of Defence Science, Engineering & Technology, 2020;3(1):1-7.
    MyJurnal
    This study is a continuation of previous research work conducted by the author on the stability of man-made slope constructed in UPNM campus. This paper presents the effects of ground water level (GWL) fluctuation on slope stability by using numerical simulation program, SlopeW. Ground water rises were simulated from 5m below the ground until 10m above the ground. Soil samples were taken from the site and tested in laboratory and then were incorporated into the program. It was found that the stability of the slope decreased with an increase of GWL. The critical slip surface formed by each case study is categorised as toe failure with circular and non-circular shapes.
    Matched MeSH terms: Water; Groundwater
  18. Distribution of linear alkylbenzenes (LABs) in riverine and coastal environments in South and Southeast Asia
    Isobe KO, Zakaria MP, Chiem NH, Minh le Y, Prudente M, Boonyatumanond R, et al.
    Water Res, 2004 May;38(9):2448-58.
    PMID: 15142807
    This paper reports the result of sewage pollution monitoring conducted in South and Southeast Asia during 1998-2003 using linear alkylbenzenes (LABs) as molecular tracers of sewage contamination. Eighty-nine water samples collected from Malaysia, Vietnam, and Japan (Tokyo), and 161 surface sediment samples collected from Tokyo, Thailand, Malaysia, Philippines, Vietnam, Cambodia, Indonesia, and India were analyzed for alkylbenzenes. The concentration range of SigmaLABs in river water particles in Southeast Asia (<0.005-0.913 microg/L) was comparable to or higher than those found in Tokyo (<0.005-0.638 microg/L). I/E ratios (a ratio of internal to external isomers of LABs) in tropical Asian waters were close to the value of LABs in raw sewage ( approximately 1) and much lower than those in secondary effluents (3-5). This suggests that untreated or inadequately treated sewage is discharged into the water. SigmaLABs concentrations in sediments from South and Southeast Asia ranged from <0.002-42.6 microg/g-dry with the highest concentration occurring at several populous cities. Low I/E ratios of the sediments with high SigmaLABs concentrations suggest a heavy load of untreated sewage. Clearly in view of the current data and evidence of the implications of sewage pollution, this paper highlights the necessity of the continuation of water treatment system improvement in tropical Asia.
    Matched MeSH terms: Fresh Water/chemistry; Water Pollutants, Chemical/analysis*
  19. Formation, modeling and validation of trihalomethanes (THM) in Malaysian drinking water: a case study in the districts of Tampin, Negeri Sembilan and Sabak Bernam, Selangor, Malaysia
    Abdullah MP, Yew CH, Ramli MS
    Water Res, 2003 Nov;37(19):4637-44.
    PMID: 14568050
    A modeling procedure that predicts trihalomethane (THM) formation from field sampling at the treatment plant and along its distribution system using Tampin district, Negeri Sembilan and Sabak Bernam district, Selangor as sources of data were studied and developed. Using Pearson method of correlation, the organic matter measured as TOC showed a positive correlation with formation of THM (r=0.380,P=0.0001 for Tampin and r=0.478,P=0.0001 for Sabak Bernam). Similar positive correlation was also obtained for pH in both districts with Tampin (r=0.362,P=0.0010) and Sabak Bernam (r=0.215,P=0.0010). Chlorine dosage was also found to have low correlation with formation of THM for the two districts with Tampin (r=0.233,P=0.0230) and Sabak Bernam (r=0.505,P=0.0001). Distance from treatment plant was found to have correlation with formation of THM for Tampin district with r=0.353 and P=0.0010. Other parameters such as turbidity, ammonia, temperature and residue chlorine were found to have no correlation with formation of THM. Linear and non-linear models were developed for these two districts. The results obtained were validated using three different sets of field data obtained from own source and district of Seremban (Pantai and Sg. Terip), Negeri Sembilan. Validation results indicated that there was significant difference in the predictive and determined values of THM when two sets of data from districts of Seremban were used with an exception of field data of Sg. Terip for non-linear model developed for district of Tampin. It was found that a non-linear model is slightly better than linear model in terms of percentage prediction errors. The models developed were site specific and the predictive capabilities in the distribution systems vary with different environmental conditions.
    Matched MeSH terms: Water Pollutants, Chemical/analysis*; Water Purification/methods*
  20. Composition, sources, and bioavailability of nitrogen in a longitudinal gradient from freshwater to estuarine waters
    Jani J, Toor GS
    Water Res, 2018 06 15;137:344-354.
    PMID: 29571112 DOI: 10.1016/j.watres.2018.02.042
    Nitrogen (N) transport from land to water is a dominant contributor of N in estuarine waters leading to eutrophication, harmful algal blooms, and hypoxia. Our objectives were to (1) investigate the composition of inorganic and organic N forms, (2) distinguish the sources and biogeochemical mechanisms of nitrate-N (NO3-N) transport using stable isotopes of NO3- and Bayesian mixing model, and (3) determine the dissolved organic N (DON) bioavailability using bioassays in a longitudinal gradient from freshwater to estuarine ecosystem located in the Tampa Bay, Florida, United States. We found that DON was the most dominant N form (mean: 64%, range: 46-83%) followed by particulate organic N (PON, mean: 22%, range: 14-37%), whereas inorganic N forms (NOx-N: 7%, NH4-N: 7%) were 14% of total N in freshwater and estuarine waters. Stable isotope data of NO3- revealed that nitrification was the main contributor (36.4%), followed by soil and organic N sources (25.5%), NO3- fertilizers (22.4%), and NH4+ fertilizers (15.7%). Bioassays showed that 14 to 65% of DON concentrations decreased after 5-days of incubation indicating utilization of DON by microbes in freshwater and estuarine waters. These results suggest that despite low proportion of inorganic N forms, the higher concentrations and bioavailability of DON can be a potential source of N for algae and bacteria leading to water quality degradation in the estuarine waters.
    Matched MeSH terms: Fresh Water/analysis*; Fresh Water/chemistry; Water Quality
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