Displaying publications 1 - 20 of 177 in total

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  1. Kzar AA, Mat Jafri MZ, Mutter KN, Syahreza S
    PMID: 26729148 DOI: 10.3390/ijerph13010092
    Decreasing water pollution is a big problem in coastal waters. Coastal health of ecosystems can be affected by high concentrations of suspended sediment. In this work, a Modified Hopfield Neural Network Algorithm (MHNNA) was used with remote sensing imagery to classify the total suspended solids (TSS) concentrations in the waters of coastal Langkawi Island, Malaysia. The adopted remote sensing image is the Advanced Land Observation Satellite (ALOS) image acquired on 18 January 2010. Our modification allows the Hopfield neural network to convert and classify color satellite images. The samples were collected from the study area simultaneously with the acquiring of satellite imagery. The sample locations were determined using a handheld global positioning system (GPS). The TSS concentration measurements were conducted in a lab and used for validation (real data), classification, and accuracy assessments. Mapping was achieved by using the MHNNA to classify the concentrations according to their reflectance values in band 1, band 2, and band 3. The TSS map was color-coded for visual interpretation. The efficiency of the proposed algorithm was investigated by dividing the validation data into two groups. The first group was used as source samples for supervisor classification via the MHNNA. The second group was used to test the MHNNA efficiency. After mapping, the locations of the second group in the produced classes were detected. Next, the correlation coefficient (R) and root mean square error (RMSE) were calculated between the two groups, according to their corresponding locations in the classes. The MHNNA exhibited a higher R (0.977) and lower RMSE (2.887). In addition, we test the MHNNA with noise, where it proves its accuracy with noisy images over a range of noise levels. All results have been compared with a minimum distance classifier (Min-Dis). Therefore, TSS mapping of polluted water in the coastal Langkawi Island, Malaysia can be performed using the adopted MHNNA with remote sensing techniques (as based on ALOS images).
    Matched MeSH terms: Water Pollution
  2. Praveena SM, Aris AZ
    Mar Pollut Bull, 2013 Feb 15;67(1-2):196-9.
    PMID: 23260650 DOI: 10.1016/j.marpolbul.2012.11.037
    Tidal variation in tropical coastal water plays an important role on physicochemical characteristics and nutrients concentration. Baseline measurements were made for nutrients concentration and physicochemical properties of coastal water, Port Dickson, Malaysia. pH, temperature, oxidation reduction potential, salinity and electrical conductivity have high values at high tides. Principal Components Analysis (PCA) was used to understand spatial variation of nutrients and physicochemical pattern of Port Dickson coastal water at high and low tide. Four principal components of PCA were extracted at low and high tides. Positively loaded nutrients with negative loadings of DO, pH and ORP in PCA outputs indicated nutrients contribution related with pollution sources. This study output will be a baseline frame for future studies in Port Dickson involving water and sediment samples. Water and sediment samples of future monitoring studies in Port Dickson coastal water will help in understanding of coastal water chemistry and pollution sources.
    Matched MeSH terms: Water Pollution, Chemical/statistics & numerical data
  3. Pek CK, Jamal O
    J Environ Manage, 2011 Nov;92(11):2993-3001.
    PMID: 21820795 DOI: 10.1016/j.jenvman.2011.07.013
    In Malaysia, most municipal wastes currently are disposed into poorly managed 'controlled tipping' systems with little or no pollution protection measures. This study was undertaken to assist the relevant governmental bodies and service providers to identify an improved waste disposal management strategy. The study applied the choice experiment technique to estimate the nonmarket values for a number of waste disposal technologies. Implicit prices for environmental attributes such as psychological fear, land use, air pollution, and river water quality were estimated. Compensating surplus estimates incorporating distance from the residences of the respondents to the proposed disposal facility were calculated for a number of generic and technology-specific choice sets. The resulting estimates were higher for technology-specific options, and the distance factor was a significant determinant in setting an equitable solid waste management fee.
    Matched MeSH terms: Water Pollution/prevention & control
  4. Mei Siang Ma, Zalini Yunus, Zukri Ahmad, Farizah Abdul Fatah
    Sains Malaysiana, 2015;44:187-192.
    Water from the dental unit waterlines (DUWLs) is known to contaminate with microbial from the biofilm that formed in the tubing system. The water quality from DUWLs is important to patients and dental health care professionals as they could be infected either directly from the contaminated water or aerosol that is generated during dental procedures. Suppliers claimed that dental units supplied to the hospital can only use a specific disinfectant which is uneconomic compared with the others. The aims of this study were to evaluate and compare the efficacy of different disinfectant on the water quality of DUWLs. Four disinfectants (Calbenium, A-dec ICX tablet, Dentel 5, Metassys) and distil water were evaluated. 350 mL water sample was collected separately, from the outlet of high-speed handpiece, scaler, 3-ways syringe and cup filler into a sterile thiosulfate bag on the 1st, 2nd, 4th, 8th, 12th and 24th weeks of the study. The samples were tested on the following day for total viable count (TVC). There is significant difference in the efficacies of the different disinfectants. Only one disinfectant consistently produces water quality within the recommended level of American Dental Association (ADA). Within the limitation of this study, it was found that there is alternative disinfectant that can reduce the TVC to the level recommended by ADA. However, the water qualities produced with these disinfectants were not consistent although they did not cause any technical problem to the dental units during the period of study.
    Matched MeSH terms: Water Pollution
  5. Sehreen F, Masud MM, Akhtar R, Masum MRA
    Environ Monit Assess, 2019 Jun 22;191(7):457.
    PMID: 31230139 DOI: 10.1007/s10661-019-7595-9
    The city of Dhaka has been ranked repeatedly as the most polluted, the most populous, and the most unbearable city in the world. More than 19.5 million inhabitants live in Dhaka, and the population growth rate of urban areas in Bangladesh is almost double that of rural areas. Rapid urbanization is one of the leading contributors to water pollution in Dhaka and could prevent the country from achieving sustainable development. Therefore, this study estimates respondents' willingness to pay (WTP) to improve water pollution management systems and identifies factors that influence WTP in Dhaka. This study employed the contingent valuation method (CVM) to estimate WTP of the respondents. Data were collected using a structured questionnaire with CVM questions, which was distributed to households in the study areas. The results revealed that 67% of the respondents are willing to pay for an improved water pollution management system, while 31.8% of households are unwilling to pay. The study also found that socio-economic factors (e.g., income and education) and perception significantly influence WTP. Therefore, this paper will provide directives for policymakers in developing an effective policy framework, as well as sensitize all stakeholders to the management of water pollution in Dhaka. The study suggests that social institutions, financial institutions, banks, non-government organizations (NGOs), insurance companies, and the government could provide effective outreach programs for water pollution management as part of their social responsibility.
    Matched MeSH terms: Water Pollution/analysis*
  6. Sim SF, Ling TY, Lau S, Jaafar MZ
    Environ Monit Assess, 2015 Apr;187(4):181.
    PMID: 25773897 DOI: 10.1007/s10661-015-4416-7
    A computer-aided multivariate water quality index is developed based on partial least squares (PLS) regression. The index is termed as the partial least squares water quality index (PLS-WQI). Briefly, a training set was computationally generated based on the guideline of National Water Quality Standards for Malaysia (NWQS) to predict the water quality. The index is benchmarked with the well-established index developed by the Department of Environment, Malaysia (DOE-WQI). The PLS-WQI is a continuous variable with the value closer to I indicating good water quality and closer to V indicating poor water quality. Unlike other conventional indexing methods, the algorithm calculates the index in a multivariate manner. The algorithm allows rapid processing of a large dataset without tedious calculation; it can be an efficient tool for spatial and temporal routine monitoring of water quality. Although the algorithm is designed based on the guideline of NWQS, it can be easily adapted to accommodate other guidelines. The algorithm was evaluated and demonstrated on the simulated and real datasets. Results indicate that the algorithm is robust and reliable. Based on six parameters, the overall ratings derived are inversely correlated to DOE-WQI. When the number of parameter is increased, the overall ratings appear to provide better insights into the water quality.
    Matched MeSH terms: Water Pollution/statistics & numerical data*
  7. Suratman S, Tahir NM, Latif MT
    Bull Environ Contam Toxicol, 2012 May;88(5):755-8.
    PMID: 22392007 DOI: 10.1007/s00128-012-0574-2
    The distribution of total petrogenic hydrocarbon was investigated in the subsurface water of Setiu Wetland from July to October 2008. The concentration was quantified by UV-fluorescence spectroscopy and ranged from 4 to 121 μg/L (mean 60 ± 41 μg/L). Higher total petrogenic hydrocarbon concentrations were found in area with high boating activities suggesting that the contribution is likely related to fossil fuel combustion. The present study also revealed that the total petrogenic hydrocarbon values are still lower that those reported in Malaysian coastal waters.
    Matched MeSH terms: Water Pollution, Chemical/statistics & numerical data
  8. Halmi, M.I.E., Baskaran Gunasekaran, Othman, A.R., Shukor, M.Y., Kamaruddin, K., Dahalan, F.A., et al.
    MyJurnal
    The volume of contaminated rivers in Malaysia continues to keep rising through the years. The
    cost of instrumental monitoring is uneconomical and prohibits schedule monitoring of
    contaminants particularly heavy metals. In this work, a rapid enzyme assay utilizing the
    molybdenum-reducing enzyme as an inhibitive assay, prepared in crude form from the
    molybdenum-reducing bacterium Serratia sp. strain DRY5 has been developed for monitoring
    the heavy metals mercury, silver, copper and chromium in contaminated waters in the Juru
    Industrial Estate. The crude enzyme extract transformed soluble molybdenum
    (phosphomolybdate) into a deep blue solution, which is inhibited by heavy metals such as
    mercury, silver, copper and chromium. The IC50 and Limits of Detection (LOD) values for
    mercury, copper, silver and cadmium were 0.245, 0.298, 0.367, 0.326, and 0.124, 0.086, 0.088
    and 0.094 mg L-1, respectively. The assay is rapid, and can be carried out in less than 10 minutes.
    In addition, the assay can be carried out at ambient temperature. The IC50 values for these heavy
    metals are more sensitive than several established assays. Water samples from various locations
    in the month of November from the Juru Industrial Estate (Penang) were tested for the presence
    of heavy metals using the developed assay. Enzyme activity was nearly inhibited for water
    samples from several locations. The presence of heavy metals was confirmed instrumentally
    using Atomic Emission Spectrometry and a Flow Injection Mercury System. The assay is rapid
    and simple and can be used as a first screening method for large scale monitoring of heavy
    metals.
    Matched MeSH terms: Water Pollution
  9. Lim CTS, Lee SE
    Pak J Med Sci, 2017 10 27;33(4):1047-1049.
    PMID: 29067090 DOI: 10.12669/pjms.334.13112
    Ralstonia mannitolilytica is a gram negative soil bacterium. Ralstonia infection though rare, has become the emerging nosocomial pathogens in hospital settings. Various clinical manifestations had been described as well as the mode of transmission. Despite its low virulence factor, it is able to survive under harsh condition and this may potentially cause significant morbidity and mortality especially in immunocompromised patients. Outbreak of Ralstonia mannitolilytica infections in the hospital are typically associated with contaminated medical supplies or instruments. We described here a case of Ralstonia mannitolilytica infection in a dialysis patient that occurred during the municipal reservoir water contamination crisis. In this report, we will also describe the behaviour of Ralstonia genus and its 4 main species, namely R. pickettii, R. solanacearum, R. insidiosa, and R. mannitolilytica and the choices of antibiotic therapy based on literature review.
    Matched MeSH terms: Water Pollution
  10. Goh HW, Lem KS, Azizan NA, Chang CK, Talei A, Leow CS, et al.
    Environ Sci Pollut Res Int, 2019 May;26(15):14904-14919.
    PMID: 30977005 DOI: 10.1007/s11356-019-05041-0
    Bioretention systems have been implemented as stormwater best management practices (BMPs) worldwide to treat non-point sources pollution. Due to insufficient research, the design guidelines for bioretention systems in tropical countries are modeled after those of temperate countries. However, climatic factors and stormwater runoff characteristics are the two key factors affecting the capacity of bioretention system. This paper reviews and compares the stormwater runoff characteristics, bioretention components, pollutant removal requirements, and applications of bioretention systems in temperate and tropical countries. Suggestions are given for bioretention components in the tropics, including elimination of mulch layer and submerged zone. More research is required to identify suitable additives for filter media, study tropical shrubs application while avoiding using grass and sedges, explore function of soil faunas, and adopt final discharged pollutants concentration (mg/L) on top of percentage removal (%) in bioretention design guidelines.
    Matched MeSH terms: Water Pollution/prevention & control*
  11. Ryan PG
    Mar Pollut Bull, 2013 Apr 15;69(1-2):128-36.
    PMID: 23415747 DOI: 10.1016/j.marpolbul.2013.01.016
    A size and distance-based technique was used to assess the distribution, abundance and composition of floating marine debris in the northeast Indian Ocean. Densities of floating litter (>1 cm) were greater and more variable in the Straits of Malacca (578±219 items km(-2)) than in oceanic waters of the Bay of Bengal (8.8±1.4 items km(-2)). The density of debris in the Straits was correlated with terrestrial vegetation, and peaked close to urban centres, indicating the predominance of land-based sources. In the Bay of Bengal, debris density increased north of 17°N mainly due to small fragments probably carried in run-off from the Ganges Delta. The low densities in the Bay of Bengal relative to model predictions may result from biofouling-induced sinking and wind-driven export of debris items. Standardised data collection protocols are needed for counts of floating debris, particularly as regards the size classes used, to facilitate comparisons among studies.
    Matched MeSH terms: Water Pollution/statistics & numerical data
  12. MAHONY BJ, MORAN JG
    J R Army Med Corps, 1964;110:13-4.
    PMID: 14125191
    Matched MeSH terms: Water Pollution*
  13. Chew KW, Chia SR, Chia WY, Cheah WY, Munawaroh HSH, Ong WJ
    Environ Pollut, 2021 Mar 01;278:116836.
    PMID: 33689952 DOI: 10.1016/j.envpol.2021.116836
    The remarkable journey of progression of mankind has created various impacts in the form of polluted environment, amassed heavy metals and depleting resources. This alarming situation demands sustainable energy resources and approaches to deal with these environmental hazards and power deficit. Pyrolysis and co-pyrolysis address both energy and environmental issues caused by civilization and industrialization. The processes use hazardous waste materials including waste tires, plastic and medical waste, and biomass waste such as livestock waste and agricultural waste as feedstock to produce gas, char and pyrolysis oil for energy production. Usage of hazardous materials as pyrolysis and co-pyrolysis feedstock reduces disposal of harmful substances into environment, reducing occurrence of soil and water pollution, and substituting the non-renewable feedstock, fossil fuels. As compared to combustion, pyrolysis and co-pyrolysis have less emission of air pollutants and act as alternative options to landfill disposal and incineration for hazardous materials and biomass waste. Hence, stabilizing heavy metals and solving the energy and waste management problems. This review discusses the pyrolysis and co-pyrolysis of biomass and harmful wastes to strive towards circular economy and eco-friendly, cleaner energy with minimum waste disposal, reducing negative impact on the planet and creating future possibilities.
    Matched MeSH terms: Water Pollution
  14. Lau S, Mohamed M, Yen AT, Su'ut S
    Sci Total Environ, 1998 Jun 18;214:113-21.
    PMID: 9646520
    Heavy metals in the aquatic environment have to date come mainly from naturally occurring geochemical materials. However, this has been enhanced by human activity such as gold mining in the case of heavy metal pollution in Sg Sarawak Kanan. The high suspended solid loads in the river have quite efficiently removed most soluble metals from the water and trapped them in the bottom sediment. Three freshwater mollusc species were collected at the point source of the heavy metal pollutants and analysed for the heavy metal contents in their tissues and shells. Two of the mollusc species (Brotia costula and Melanoides tuberculata) are purely freshwater species while the Clithon sp. nr retropictus is able to survive in fresh and brackish water environments. The Brotia costula and the Clithon sp. are the edible species which are sold in the market. Accumulation of As, Cu, Fe, Se and Zn in all the three mollusc species were determined and the level of As in the tissues of Brotia costula and the Clithon sp. was much higher than the permissible level for human consumption. The mollusc species also demonstrated different preferences for the uptake of different metals. Variations in the heavy metal contents in the shell and tissues of the same species were also observed.
    Matched MeSH terms: Water Pollution, Chemical
  15. Chou L, Dai J, Qian X, Karimipour A, Zheng X
    Agric Water Manag, 2021 Feb 28;245:106583.
    PMID: 33100487 DOI: 10.1016/j.agwat.2020.106583
    With the development of Chinese economy, more and more attention has been paid to environmental protection, the implementation of water price policy affects economic and environmental changes in China. This paper analyzes the impact of water price policy on agricultural land use and the scale of water pollution discharge in 240 cities in China between 2001 and 2017, by including data from China Urban Statistical Yearbook and China Land & Resources Almanac. The theoretical analysis of this study indicates that the optimal scale of pollution depends on the local initial endowment, economic investment capital and the marginal cost of environmental pollution caused by government's economic activities. Furtherly, the economic activities have a worsening impact on environmental pollution, but when the government implements environmental protection and water price policy measures in response to environmental pollution caused by economic activities, it has a significant impact on the decline in the scale of pollution. The government has promoted the pollution suppression model in the formulation of water prices, which has internalized the external cost of pollution in economic activities and can effectively reduce the scale of agricultural water pollution discharge.
    Matched MeSH terms: Water Pollution
  16. Lili, Z.M., Noridah, O.
    MyJurnal
    Acute Gastroenteritis (AGE) is common world wide and is a major health problem. The commonest cause is from contaminated water or food. Common infective agents are Rotavirus, Staph. aureus and Bacillus cereus. There was an AGE outbreak in Ipoh City from late August till early October 2006. Epidemiological and laboratory investigations were done. Fresh stool samples were taken from symptomatic patients. Water and food sampling were also done. Descriptive analysis of the outbreak was done. A total of 170 patients, mostly between 1 - 5 years of age, were affected. The highest incidents were seen in Bercham. Fever and diarrhea were the prominent features. Two stool samples (13.3%) were positive for E.coli and rotavirus respectively. Twelve of the twenty (60%) water samples taken were contaminated with coliform and fecal matter. Twenty-one of the eighty ((26.3%) food samples taken grew either E.coli, Staph. aureus or Bacillus cereus. It was concluded that a general source was responsible for this problem. The water supply to Ipoh City and the surrounding area is the most likely source. Novovirus was suspected as the organism involved because of the self-limiting and mild nature of the illness that occurred in this outbreak.
    The AGE outbreak in Kinta District in September 2006 is due to contaminated
    water supply from two water treatment
    Matched MeSH terms: Water Pollution
  17. Zainurin SN, Wan Ismail WZ, Mahamud SNI, Ismail I, Jamaludin J, Ariffin KNZ, et al.
    Int J Environ Res Public Health, 2022 Oct 28;19(21).
    PMID: 36360992 DOI: 10.3390/ijerph192114080
    Nowadays, water pollution has become a global issue affecting most countries in the world. Water quality should be monitored to alert authorities on water pollution, so that action can be taken quickly. The objective of the review is to study various conventional and modern methods of monitoring water quality to identify the strengths and weaknesses of the methods. The methods include the Internet of Things (IoT), virtual sensing, cyber-physical system (CPS), and optical techniques. In this review, water quality monitoring systems and process control in several countries, such as New Zealand, China, Serbia, Bangladesh, Malaysia, and India, are discussed. Conventional and modern methods are compared in terms of parameters, complexity, and reliability. Recent methods of water quality monitoring techniques are also reviewed to study any loopholes in modern methods. We found that CPS is suitable for monitoring water quality due to a good combination of physical and computational algorithms. Its embedded sensors, processors, and actuators can be designed to detect and interact with environments. We believe that conventional methods are costly and complex, whereas modern methods are also expensive but simpler with real-time detection. Traditional approaches are more time-consuming and expensive due to the high maintenance of laboratory facilities, involve chemical materials, and are inefficient for on-site monitoring applications. Apart from that, previous monitoring methods have issues in achieving a reliable measurement of water quality parameters in real time. There are still limitations in instruments for detecting pollutants and producing valuable information on water quality. Thus, the review is important in order to compare previous methods and to improve current water quality assessments in terms of reliability and cost-effectiveness.
    Matched MeSH terms: Water Pollution
  18. Yap CK, Chong CM, Tan SG
    Environ Monit Assess, 2011 Mar;174(1-4):389-400.
    PMID: 20437264 DOI: 10.1007/s10661-010-1464-x
    It has been widely reported that allozyme frequency variation is a potential indicator of heavy metal-induced impacts in aquatic populations. In the present study, wild populations of horseshoe crab (Carcinoscorpius rotundicauda) were collected from contaminated and uncontaminated sites of Peninsular Malaysia. By adopting horizontal starch gel electrophoresis, seven enzyme systems were used to study allozyme polymorphisms. Nine polymorphic loci were observed in C. rotundicauda. The relationships of allozyme variations with the concentrations of Cd, Cu, Ni, and Zn in sediments and in muscle tissues of horseshoe crabs were determined. Based on genetic distance, the lower mean value of Nei's D (0.017) indicated that both of the contaminated populations of Kg. Pasir Puteh and Kuala Juru were very closely related when compared to the relatively uncontaminated Pantai Lido population. Higher heterozygosities were shown by the contaminated populations when compared to the uncontaminated population. Different allelic frequencies could be observed for the aldolase (ALD; E.C. 2.7.5.1) locus between the contaminated and uncontaminated populations of C. rotundicauda. The dendrogram of genetic relationships of the three populations of C. rotundicauda showed the same clustering pattern as the dendrograms are based on heavy metals in the sediments and in the horseshoe crabs' abdominal muscles. From the F statistics, the present study showed that the three populations of horseshoe crabs were considered to have undergone moderate genetic differentiation with a mean F (ST) value of 0.092 .The current results suggest that allozyme polymorphism in horseshoe crabs is a potential biomonitoring tool for metal contamination, although further validation is required.
    Matched MeSH terms: Water Pollution*
  19. Mojiri A, Ahmad Z, Tajuddin RM, Arshad MF, Gholami A
    Environ Monit Assess, 2017 Jul;189(7):337.
    PMID: 28612336 DOI: 10.1007/s10661-017-6052-x
    Water pollution is a global problem. During current study, ammonia, phosphate, phenol, and copper(II) were removed from aqueous solution by subsurface and surface flow constructed wetland. In current investigation, distilled water was polluted with four contaminants including ammonia, phosphate, copper (Cu), and phenol. Response surface methodology and central composite design were applied to optimize pollutant removal during treatment by subsurface flow constructed wetland (SSFCW). Contact time (12 to 80 h) and initial pollutant concentration (20 to 85 mg/L) were selected as independent factors; some upper and lower ranges were also monitored for accuracy. In SSFCW, water hyacinth transplanted in two substrate layers, namely zeolite and cockle shell. SSFCW removed 87.7, 81.4, 74.7, and 54.9% of ammonia, phosphate, Cu, and phenol, respectively, at optimum contact time (64.5 h) and initial pollutant concentration (69.2 mg/L). Aqueous solution was moved to a surface flow constructed wetland (SFCW) after treating via SSFCW at optimum conditions. In SFCW, Typha was transplanted to a fixed powdered substrate layer, including bentonite, zeolite, and cockle shell. SFCW could develop performance of this combined system and could improve elimination efficacy of the four contaminants to 99.99%. So this combined CW showed a good performance in removing pollutants. Graphical abstract Wetlands arrangement for treating aqueous solution in current study.
    Matched MeSH terms: Water Pollution
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