Displaying publications 101 - 120 of 291 in total

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  1. The application of chemometrics in metals source of identification in Brunei Bay surface sediment
    Ong MC, Yong JC, Shaari H, Joseph B, Shazili NAM, Pradit S, et al.
    Environ Geochem Health, 2023 Jun;45(6):3777-3787.
    PMID: 36574138 DOI: 10.1007/s10653-022-01456-w
    Brunei Bay is a unique ecosystem which offers a vast biodiversity. This study was carried out to define the source of metals in the surface sediment of Brunei Bay to ensure the bay's health. The secondary data were analysed using chemometrics analysis to verify the possible factors that influence metals distribution in Brunei Bay sediment. Samples were collected several times during 2013 to 2014 using Ponar grab at 16 stations within the bay. Samples were then dried, pre-treated, digested and analysed using Inductively Coupled Plasma Mass Spectrometry (ICPMS) in the laboratory. Overall, the mean concentration of metal, sediment pH and clay fraction were significantly changed during different sampling periods, as the changes were presumed affected by seasonal changes. The Pearson correlation has pointed that metals were dominantly derived by natural input; however, the total organic carbon was proven to be derived by anthropogenic sources. Moreover, the principal component analysis has verified that the distribution of metals in the bay's sediment was dominantly influenced by natural processes. However, the utilization and manipulation of marine resources are slightly affecting the bay's ecosystem which may deteriorate the ecosystem health soon.
    Matched MeSH terms: Environmental Monitoring/methods
  2. Fulltext A novel report on the occurrence of microplastics in Pekalongan River Estuary, Java Island, Indonesia
    Ismanto A, Hadibarata T, Kristanti RA, Sugianto DN, Widada S, Atmodjo W, et al.
    Mar Pollut Bull, 2023 Nov;196:115563.
    PMID: 37797535 DOI: 10.1016/j.marpolbul.2023.115563
    This study aimed to address the pressing issue of plastic pollution in aquatic ecosystems by assessing the prevalence and distribution of microplastics (MPs) in water and riverbank sediments of the Pekalongan River, a vital water source in Indonesia. From the present findings, MP concentrations in water ranged from 45.2 to 99.1 particles/L, while sediment concentrations ranged from 0.77 to 1.01 particles/g. This study revealed that fragment and film MPs constituted 30.1 % and 25.4 % of the total, respectively, with MPs measuring <1 mm and constituting 51.4 % of the total. Colored MPs, particularly blue and black MPs, accounted for 34 % of the total. The primary polymer components, as determined via Fourier transform infrared spectroscopy, were identified as polystyrene, polyester, and polyamide. In response to the escalating plastic waste crisis caused by single-use plastics, Pekalongan's local government implemented refuse segregation and recycling programs as part of its efforts to transition toward zero-waste practices.
    Matched MeSH terms: Environmental Monitoring/methods
  3. Study on Carapace Width Growth Band Counts Relationship of Orange Mud Crab, Scylla olivacea (Herbst, 1796) from Terengganu Coastal Waters, Malaysia
    Hasyima Ismail N, Amin Safwan A, Fairuz Fozi N, Megat FH, Muhd Farouk H, Kamaruddin SA, et al.
    Pak J Biol Sci, 2017;20(3):140-146.
    PMID: 29023005 DOI: 10.3923/pjbs.2017.140.146
    BACKGROUND: Orange mud crab Scylla olivacea is one of the most important fisheries resources. A new development in ageing technique of crustaceans has been introduced. The detection of growth band deposited in hard structure of gastric mill in the cardiac stomach are found retained after moulting process can be used as age indicator and growth estimation.

    OBJECTIVE: This study was carried out to determine the comparison between carapace width and growth band count of S. olivacea in Malaysia.

    MATERIALS AND METHODS: Samples were collected from Setiu Wetlands, Terengganu, Malaysia from February until August, 2016. Samples were categorized based on their morphological measurements. The mesocardiac and zygocardiac ossicles in the gastric mill of S. olivacea was dissected out and preserved in solutions and underwent a cross sectioning process. A total of 76 of wild S. olivacea ranging from 6.56 to 12.84 cm in carapace width were analysed. The growth band counts were examined for each individual and ranging from 1 to 3 band counts.

    RESULTS: A positive linear relation was observed between CW and GBC with r2 = 0.5178, p<0.01. Overall, there was a strong, positive correlation between CW and GBC. Increase in CW were correlated with increases in GBC respectively for this species.

    CONCLUSION: Therefore, the carapace width, growth band counts and body weight can be used to improve data on growth, recruitment, maturation and mortality. Thus, this study would able to improve new ageing technique and contribute greatly to improve the conservation and management of S. olivacea in Setiu Wetlands, Terengganu, Malaysia.

    Matched MeSH terms: Environmental Monitoring/methods*
  4. A review of personal exposure studies in selected Asian countries' public transport microenvironments: lessons learned and future directions
    Otuyo MK, Nadzir MSM, Latif MT, Din SAM
    Environ Sci Pollut Res Int, 2023 Dec;30(58):121306-121337.
    PMID: 37993649 DOI: 10.1007/s11356-023-30923-9
    This comprehensive paper conducts an in-depth review of personal exposure and air pollutant levels within the microenvironments of Asian city transportation. Our methodology involved a systematic analysis of an extensive body of literature from diverse sources, encompassing a substantial quantity of studies conducted across multiple Asian cities. The investigation scrutinizes exposure to various pollutants, including particulate matters (PM10, PM2.5, and PM1), carbon dioxide (CO2), formaldehyde (CH2O), and total volatile organic compounds (TVOC), during transportation modes such as car travel, bus commuting, walking, and train rides. Notably, our review reveals a predominant focus on PM2.5, followed by PM10, PM1, CO2, and TVOC, with limited attention given to CH2O exposure. Across the spectrum of Asian cities and transportation modes, exposure concentrations exhibited considerable variability, a phenomenon attributed to a multitude of factors. Primary sources of exposure encompass motor vehicle emissions, traffic dynamics, road dust, and open bus doors. Furthermore, our findings illuminate the influence of external environments, particularly in proximity to train stations, on pollutant levels inside trains. Crucial factors affecting exposure encompass ventilation conditions, travel-specific variables, seat locations, vehicle types, and meteorological influences. The culmination of this rigorous review underscores the need for standardized measurements, enhanced ventilation systems, air filtration mechanisms, the adoption of clean energy sources, and comprehensive public education initiatives aimed at reducing pollutant exposure within city transportation microenvironments. Importantly, our study contributes to the growing body of knowledge surrounding this subject, offering valuable insights for policymakers and researchers dedicated to advancing air quality standards and safeguarding public health.
    Matched MeSH terms: Environmental Monitoring/methods
  5. Fulltext Development of Biopolymer and Conducting Polymer-Based Optical Sensors for Heavy Metal Ion Detection
    Ramdzan NSM, Fen YW, Anas NAA, Omar NAS, Saleviter S
    Molecules, 2020 May 30;25(11).
    PMID: 32486124 DOI: 10.3390/molecules25112548
    Great efforts have been devoted to the invention of environmental sensors as the amount of water pollution has increased in recent decades. Chitosan, cellulose and nanocrystalline cellulose are examples of biopolymers that have been intensively studied due to their potential applications, particularly as sensors. Furthermore, the rapid use of conducting polymer materials as a sensing layer in environmental monitoring has also been developed. Thus, the incorporation of biopolymer and conducting polymer materials with various methods has shown promising potential with sensitively and selectively toward heavy metal ions. In this feature paper, selected recent and updated investigations are reviewed on biopolymer and conducting polymer-based materials in sensors aimed at the detection of heavy metal ions by optical methods. This review intends to provide sufficient evidence of the potential of polymer-based materials as sensing layers, and future outlooks are considered in developing surface plasmon resonance as an excellent and valid sensor for heavy metal ion detection.
    Matched MeSH terms: Environmental Monitoring/methods
  6. Environmental DNA metabarcoding of freshwater fish in Malaysian tropical rivers using short-read nanopore sequencing as a potential biomonitoring tool
    Munian K, Ramli FF, Othman N, Mahyudin NAA, Sariyati NH, Abdullah-Fauzi NAF, et al.
    Mol Ecol Resour, 2024 May;24(4):e13936.
    PMID: 38419264 DOI: 10.1111/1755-0998.13936
    The approach of combining cost-effective nanopore sequencing and emerging environmental DNA (eDNA) metabarcoding could prove to be a promising tool for biodiversity documentation, especially in Malaysia. Given the substantial funding constraints in recent years, especially in relation to the country's biodiversity, many researchers have been limited to conduct restricted research without extended monitoring periods, potentially hindering comprehensive surveys and could compromise the conservation efforts. Therefore, the present study aimed to evaluate the application of eDNA metabarcoding on freshwater fish using short reads generated through nanopore sequencing. This assessment focused on species detection in three selected rivers within the Endau Rompin Landscape in Malaysia. Additionally, the study compared levels of species detection between eDNA metabarcoding and conventional sampling methods, examined the effectiveness of primer choice, and applied both metabarcoding and shotgun sequencing to the eDNA approach. We successfully identified a total of 22 and 71 species with an identification threshold of >97% and >90%, respectively, through the MinION platform. The eDNA metabarcoding approach detected over 13% more freshwater fish species than when the conventional method was used. Notably, the distinction in freshwater fish detection between eDNA primers for 12S rRNA and cytochrome oxidase I was insignificant. The cost for eDNA metabarcoding proved to be more effective compared to conventional sampling with cost reduction at 33.4%. With favourable cost-effectiveness and increased species detection, eDNA metabarcoding could complement existing methods, enhance holistic diversity documentation for targeted habitats and facilitate effective conservation planning.
    Matched MeSH terms: Environmental Monitoring/methods
  7. Origins of suspended particulate matter based on sterol distribution in low salinity water mass observed in the offshore East China Sea
    Kim M, Jung JH, Jin Y, Han GM, Lee T, Hong SH, et al.
    Mar Pollut Bull, 2016 Jul 15;108(1-2):281-8.
    PMID: 27167134 DOI: 10.1016/j.marpolbul.2016.04.049
    The molecular composition and distribution of sterols were investigated in the East China Sea to identify the origins of suspended particulate matter (SPM) in offshore waters influenced by Changjiang River Diluted Water (CRDW). Total sterol concentrations ranged from 3200 to 31,900pgL(-1) and 663 to 5690pgL(-1) in the particulate and dissolved phases, respectively. Marine sterols dominated representing 71% and 66% in the particulate and dissolved phases, respectively. Typical sewage markers, such as coprostanol, were usually absent at ~250km offshore. However, sterols from allochthonous terrestrial plants were still detected at these sites. A negative relationship was observed between salinity and concentrations of terrestrial sterols in SPM, suggesting that significant amounts of terrestrial particulate matter traveled long distance offshore in the East China Sea, and the Changjiang River Diluted Water (CRDW) was an effective carrier of land-derived particulate organic matter to the offshore East China Sea.
    Matched MeSH terms: Environmental Monitoring/methods*
  8. Accumulation of Trace Metals in Anadara granosa and Anadara inaequivalvis from Pattani Bay and the Setiu Wetlands
    Pradit S, Shazili NA, Towatana P, Saengmanee W
    Bull Environ Contam Toxicol, 2016 Apr;96(4):472-7.
    PMID: 26725081 DOI: 10.1007/s00128-015-1717-z
    This study was undertaken to assess the levels of trace metals (As, Cd, Cu, Pb, and Zn) in two common species of cockles (Anadara granosa and Anadara inaequivalvis) from two coastal areas in Thailand (Pattani Bay) and Malaysia (the Setiu Wetlands). A total of 350 cockles were collected in February and September 2014. Trace metals were determined by Inductively Coupled Plasma Mass Spectrometry. We observed that cockles in both areas had a higher accumulation of metals in September. Notably, the biota-sediment accumulation (BSAF) of Cd was highest in both areas. A strong positive correlation of Cd with the length of the cockles at Pattani Bay (r(2) = 0.597) and the Setiu Wetlands (r(2) = 0.675) was noted. It was suggested that As could be a limiting element (BSAF < 1) of cockles obtained from Pattani Bay. In comparison with the permissible limits set by the Thailand Ministry of Public Health and the Malaysia Food Regulations, mean values of As, Cd, Cu, Pb, and Zn were within acceptable limits, but the maximum values of Cd and Pb exceeded the limits for both areas. Regular monitoring of trace metals in cockles from both areas is suggested for more definitive contamination determination.
    Matched MeSH terms: Environmental Monitoring/methods*
  9. Anthropogenic waste indicators (AWIs), particularly PAHs and LABs, in Malaysian sediments: Application of aquatic environment for identifying anthropogenic pollution
    Masood N, Zakaria MP, Halimoon N, Aris AZ, Magam SM, Kannan N, et al.
    Mar Pollut Bull, 2016 Jan 15;102(1):160-75.
    PMID: 26616745 DOI: 10.1016/j.marpolbul.2015.11.032
    Polycyclic aromatic hydrocarbons (PAHs) and linear alkylbenzenes (LABs) were used as anthropogenic markers of organic chemical pollution of sediments in the Selangor River, Peninsular Malaysia. This study was conducted on sediment samples from the beginning of the estuary to the upstream river during dry and rainy seasons. The concentrations of ƩPAHs and ƩLABs ranged from 203 to 964 and from 23 to 113 ng g(-1) dry weight (dw), respectively. In particular, the Selangor River was found to have higher sedimentary levels of PAHs and LABs during the wet season than in the dry season, which was primarily associated with the intensity of domestic wastewater discharge and high amounts of urban runoff washing the pollutants from the surrounding area. The concentrations of the toxic contaminants were determined according to the Sediment Quality Guidelines (SQGs). The PAH levels in the Selangor River did not exceed the SQGs, for example, the effects range low (ERL) value, indicating that they cannot exert adverse biological effects.
    Matched MeSH terms: Environmental Monitoring/methods
  10. Utilization of a genetic algorithm for the automatic detection of oil spill from RADARSAT-2 SAR satellite data
    Marghany M
    Mar Pollut Bull, 2014 Dec 15;89(1-2):20-29.
    PMID: 25455367 DOI: 10.1016/j.marpolbul.2014.10.041
    In this work, a genetic algorithm is applied for the automatic detection of oil spills. The procedure is implemented using sequences from RADARSAT-2 SAR ScanSAR Narrow single-beam data acquired in the Gulf of Mexico. The study demonstrates that the implementation of crossover allows for the generation of an accurate oil spill pattern. This conclusion is confirmed by the receiver-operating characteristic (ROC) curve. The ROC curve indicates that the existence of oil slick footprints can be identified using the area between the ROC curve and the no-discrimination line of 90%, which is greater than that of other surrounding environmental features. In conclusion, the genetic algorithm can be used as a tool for the automatic detection of oil spills, and the ScanSAR Narrow single-beam mode serves as an excellent sensor for oil spill detection and survey.
    Matched MeSH terms: Environmental Monitoring/methods*
  11. Assessment of heavy metals contamination in Mamut river sediments using sediment quality guidelines and geochemical indices
    Mohammad Ali BN, Lin CY, Cleophas F, Abdullah MH, Musta B
    Environ Monit Assess, 2015 Jan;187(1):4190.
    PMID: 25471626 DOI: 10.1007/s10661-014-4190-y
    This paper describes the concentration of selected heavy metals (Co, Cu, Ni, Pb, and Zn) in the Mamut river sediments and evaluate the degree of contamination of the river polluted by a disused copper mine. Based on the analytical results, copper showed the highest concentration in most of the river samples. A comparison with Interim Canadian Sediment Quality Guidelines (ICSQG) and Germany Sediment Quality Guidelines (GSQG) indicated that the sediment samples in all the sampling stations, except Mamut river control site (M1), exceeded the limit established for Cu, Ni, and Pb. On the contrary, Zn concentrations were reported well below the guidelines limit (ICSQG and GSQG). Mineralogical analysis indicated that the Mamut river sediments were primarily composed of quartz and accessory minerals such as chalcopyrite, pyrite, edenite, kaolinite, mica, and muscovite, reflected by the geological character of the study area. Enrichment factor (EF) and geoaccumulation index (Igeo) were calculated to evaluate the heavy metal pollution in river sediments. Igeo values indicated that all the sites were strongly polluted with the studied metals in most sampling stations, specifically those located along the Mamut main stream. The enrichment factor with value greater than 1.5 suggested that the source of heavy metals was mainly derived from anthropogenic activity such as mining. The degree of metal changes (δfold) revealed that Cu concentration in the river sediments has increased as much as 20 to 38 folds since the preliminary investigation conducted in year 2004.
    Matched MeSH terms: Environmental Monitoring/methods*
  12. Analysis of Southeast Asian pollution episode during June 2013 using satellite remote sensing datasets
    Vadrevu KP, Lasko K, Giglio L, Justice C
    Environ Pollut, 2014 Dec;195:245-56.
    PMID: 25087199 DOI: 10.1016/j.envpol.2014.06.017
    In this study, we assess the intense pollution episode of June 2013, in Riau province, Indonesia from land clearing. We relied on satellite retrievals of aerosols and Carbon monoxide (CO) due to lack of ground measurements. We used both the yearly and daily data for aerosol optical depth (AOD), fine mode fraction (FMF), aerosol absorption optical depth (AAOD) and UV aerosol index (UVAI) for characterizing variations. We found significant enhancement in aerosols and CO during the pollution episode. Compared to mean (2008-2012) June AOD of 0.40, FMF-0.39, AAOD-0.45, UVAI-1.77 and CO of 200 ppbv, June 2013 values reached 0.8, 0.573, 0.672, 1.77 and 978 ppbv respectively. Correlations of fire counts with AAOD and UVAI were stronger compared to AOD and FMF. Results from a trajectory model suggested transport of air masses from Indonesia towards Malaysia, Singapore and southern Thailand. Our results highlight satellite-based mapping and monitoring of pollution episodes in Southeast Asia.
    Matched MeSH terms: Environmental Monitoring/methods*
  13. Contamination of diuron in coastal waters around Malaysian Peninsular
    Ali HR, Arifin MM, Sheikh MA, Shazili NA, Bakari SS, Bachok Z
    Mar Pollut Bull, 2014 Aug 15;85(1):287-91.
    PMID: 24934440 DOI: 10.1016/j.marpolbul.2014.05.049
    The use of antifouling paints to the boats and ships is one among the threats facing coastal resources including coral reefs in recent decades. This study reports the current contamination status of diuron and its behaviour in the coastal waters of Malaysia. The maximum concentration of diuron was 285 ng/L detected at Johor port. All samples from Redang and Bidong coral reef islands were contaminated with diuron. Temporal variation showed relatively high concentrations but no significant difference (P>0.05) during November and January (North-East monsoon) in Klang ports (North, South and West), while higher levels of diuron were detected during April, 2012 (Inter monsoon) in Kemaman, and Johor port. Although no site has shown concentration above maximum permissible concentration (430 ng/L) as restricted by the Dutch Authorities, however, long term exposure studies for environmental relevance levels of diuron around coastal areas should be given a priority in the future.
    Matched MeSH terms: Environmental Monitoring/methods*
  14. Effect of asymmetrical street aspect ratios on microclimates in hot, humid regions
    Qaid A, Ossen DR
    Int J Biometeorol, 2015 Jun;59(6):657-77.
    PMID: 25108376 DOI: 10.1007/s00484-014-0878-5
    Asymmetrical street aspect ratios, i.e. different height-to-width (H1/W-H2/W) ratios, have not received much attention in the study of urban climates. Putrajaya Boulevard (northeast to southwest orientation) in Malaysia was selected to study the influence of six asymmetrical aspect ratio scenarios on the street microclimate using the Envi-met three-dimensional microclimate model (V3.1 Beta). Putrajaya Boulevard suffers from high surface and air temperature during the day due to the orientation, the low aspect ratio and the wide sky view factor. These issues are a common dilemma in many boulevards. Further, low and high symmetrical streets are incompatible with tropical regions as they offer conflicting properties during the day and at night. These scenarios are examined, therefore, to find asymmetrical streets which are able to reduce the impact of the day microclimate on boulevards, and as an alternative strategy fulfilling tropical day and night climatic conditions. Asymmetrical streets are better than low symmetrical streets in enhancing wind flow and blocking solar radiation, when tall buildings confront winds direction or solar altitudes. Therefore, mitigating heat islands or improving microclimates in asymmetrical streets based on tall buildings position which captures wind or caste shades. In northeast to southwest direction, aspect ratios of 0.8-2 reduce the morning microclimate and night heat islands yet the negative effects during the day are greater than the positive effects in the night. An aspect ratio of 2-0.8 reduces the temperature of surfaces by 10 to 14 °C and the air by 4.7 °C, recommended for enhancing boulevard microclimates and mitigating tropical heat islands.
    Matched MeSH terms: Environmental Monitoring/methods*
  15. Fulltext Determination of carbamate and organophosphorus pesticides in vegetable samples and the efficiency of gamma-radiation in their removal
    Chowdhury MA, Jahan I, Karim N, Alam MK, Abdur Rahman M, Moniruzzaman M, et al.
    Biomed Res Int, 2014;2014:145159.
    PMID: 24711991 DOI: 10.1155/2014/145159
    In the present study, the residual pesticide levels were determined in eggplants (Solanum melongena) (n = 16), purchased from four different markets in Dhaka, Bangladesh. The carbamate and organophosphorus pesticide residual levels were determined by high performance liquid chromatography (HPLC), and the efficiency of gamma radiation on pesticide removal in three different types of vegetables was also studied. Many (50%) of the samples contained pesticides, and three samples had residual levels above the maximum residue levels determined by the World Health Organisation. Three carbamates (carbaryl, carbofuran, and pirimicarb) and six organophosphates (phenthoate, diazinon, parathion, dimethoate, phosphamidon, and pirimiphos-methyl) were detected in eggplant samples; the highest carbofuran level detected was 1.86 mg/kg, while phenthoate was detected at 0.311 mg/kg. Gamma radiation decreased pesticide levels proportionately with increasing radiation doses. Diazinon, chlorpyrifos, and phosphamidon were reduced by 40-48%, 35-43%, and 30-45%, respectively, when a radiation strength of 0.5 kGy was utilized. However, when the radiation dose was increased to 1.0 kGy, the levels of the pesticides were reduced to 85-90%, 80-91%, and 90-95%, respectively. In summary, our study revealed that pesticide residues are present at high amounts in vegetable samples and that gamma radiation at 1.0 kGy can remove 80-95% of some pesticides.
    Matched MeSH terms: Environmental Monitoring/methods
  16. Development of an inhibitive assay using commercial Electrophorus electricus acetylcholinesterase for heavy metal detection
    Shukor MY, Tham LG, Halmi MI, Khalid I, Begum G, Syed MA
    J Environ Biol, 2013 Sep;34(5):967-70.
    PMID: 24558814
    Near-real-ime assay is anassay method that the whole process from sampling until results could be obtained in approximately Iess than one hour. The ElIman assay for acetyl cholinesterase (AChE) has near real-time potential due to its simplicity and fast assay time. The commercial acetylcholinesterase from Electrophorus electricus is well known for its uses in insecticides detection. A lesser known fact is AChE is also sensitive to heavy metals. A near real-time inhibitive assay for heavy metals using AChE from this source showed promising results. Several heavy metals such as copper, silver and mercury could be etected with IC50 values of1.212, 0.1185 and 0.097 mg I-1, respectively. The Limits of Detection (LOD) for copper, silver and mercury were 0.01, 0.015 and 0.01 mg I-1, respectively. TheLimits of quantitation (LOQ) or copper, silver and mercury were 0.196, 0.112 and 0.025 mg I-1, respectively. The LOQvalues for copper, silver and mercury were well below the maximum permissible limit for these metal ions as outlined by Malaysian Department of Environment. A polluted location demonstrated near real-time applicability of the assay with variation oftemporal levels of heavy metals detected. The results show that AChE from Electrophorus electricus has the potential to be used as a near real-time biomonitoring tool for heavy
    Matched MeSH terms: Environmental Monitoring/methods*
  17. Fulltext An inhibitive enzyme assay to detect mercury and zinc using protease from Coriandrum sativum
    Baskaran G, Masdor NA, Syed MA, Shukor MY
    ScientificWorldJournal, 2013;2013:678356.
    PMID: 24194687 DOI: 10.1155/2013/678356
    Heavy metals pollution has become a great threat to the world. Since instrumental methods are expensive and need skilled technician, a simple and fast method is needed to determine the presence of heavy metals in the environment. In this study, an inhibitive enzyme assay for heavy metals has been developed using crude proteases from Coriandrum sativum. In this assay, casein was used as a substrate and Coomassie dye was used to denote the completion of casein hydrolysis. In the absence of inhibitors, casein was hydrolysed and the solution became brown, while in the presence of metal ions such as Hg²⁺ and Zn²⁺, the hydrolysis of casein was inhibited and the solution remained blue. Both Hg²⁺ and Zn²⁺ exhibited one-phase binding curve with IC₅₀ values of 3.217 mg/L and 0.727 mg/L, respectively. The limits of detection (LOD) and limits of quantitation (LOQ) for Hg were 0.241 and 0.802 mg/L, respectively, while the LOD and LOQ for Zn were 0.228 and 0.761 mg/L, respectively. The enzyme exhibited broad pH ranges for activity. The crude proteases extracted from Coriandrum sativum showed good potential for the development of a rapid, sensitive, and economic inhibitive assay for the biomonitoring of Hg²⁺ and Zn²⁺ in the aquatic environments.
    Matched MeSH terms: Environmental Monitoring/methods*
  18. Spatial and temporal air quality pattern recognition using environmetric techniques: a case study in Malaysia
    Syed Abdul Mutalib SN, Juahir H, Azid A, Mohd Sharif S, Latif MT, Aris AZ, et al.
    Environ Sci Process Impacts, 2013 Sep;15(9):1717-28.
    PMID: 23831918 DOI: 10.1039/c3em00161j
    The objective of this study is to identify spatial and temporal patterns in the air quality at three selected Malaysian air monitoring stations based on an eleven-year database (January 2000-December 2010). Four statistical methods, Discriminant Analysis (DA), Hierarchical Agglomerative Cluster Analysis (HACA), Principal Component Analysis (PCA) and Artificial Neural Networks (ANNs), were selected to analyze the datasets of five air quality parameters, namely: SO2, NO2, O3, CO and particulate matter with a diameter size of below 10 μm (PM10). The three selected air monitoring stations share the characteristic of being located in highly urbanized areas and are surrounded by a number of industries. The DA results show that spatial characterizations allow successful discrimination between the three stations, while HACA shows the temporal pattern from the monthly and yearly factor analysis which correlates with severe haze episodes that have happened in this country at certain periods of time. The PCA results show that the major source of air pollution is mostly due to the combustion of fossil fuel in motor vehicles and industrial activities. The spatial pattern recognition (S-ANN) results show a better prediction performance in discriminating between the regions, with an excellent percentage of correct classification compared to DA. This study presents the necessity and usefulness of environmetric techniques for the interpretation of large datasets aiming to obtain better information about air quality patterns based on spatial and temporal characterizations at the selected air monitoring stations.
    Matched MeSH terms: Environmental Monitoring/methods*
  19. Modeling of nitrate concentration in groundwater using artificial intelligence approach--a case study of Gaza coastal aquifer
    Alagha JS, Said MA, Mogheir Y
    Environ Monit Assess, 2014 Jan;186(1):35-45.
    PMID: 23974533 DOI: 10.1007/s10661-013-3353-6
    Nitrate concentration in groundwater is influenced by complex and interrelated variables, leading to great difficulty during the modeling process. The objectives of this study are (1) to evaluate the performance of two artificial intelligence (AI) techniques, namely artificial neural networks and support vector machine, in modeling groundwater nitrate concentration using scant input data, as well as (2) to assess the effect of data clustering as a pre-modeling technique on the developed models' performance. The AI models were developed using data from 22 municipal wells of the Gaza coastal aquifer in Palestine from 2000 to 2010. Results indicated high simulation performance, with the correlation coefficient and the mean average percentage error of the best model reaching 0.996 and 7 %, respectively. The variables that strongly influenced groundwater nitrate concentration were previous nitrate concentration, groundwater recharge, and on-ground nitrogen load of each land use land cover category in the well's vicinity. The results also demonstrated the merit of performing clustering of input data prior to the application of AI models. With their high performance and simplicity, the developed AI models can be effectively utilized to assess the effects of future management scenarios on groundwater nitrate concentration, leading to more reasonable groundwater resources management and decision-making.
    Matched MeSH terms: Environmental Monitoring/methods*
  20. Development of effluent removal prediction model efficiency in septic sludge treatment plant through clonal selection algorithm
    Ting SC, Ismail AR, Malek MA
    J Environ Manage, 2013 Nov 15;129:260-5.
    PMID: 23968912 DOI: 10.1016/j.jenvman.2013.07.022
    This study aims at developing a novel effluent removal management tool for septic sludge treatment plants (SSTP) using a clonal selection algorithm (CSA). The proposed CSA articulates the idea of utilizing an artificial immune system (AIS) to identify the behaviour of the SSTP, that is, using a sequence batch reactor (SBR) technology for treatment processes. The novelty of this study is the development of a predictive SSTP model for effluent discharge adopting the human immune system. Septic sludge from the individual septic tanks and package plants will be desuldged and treated in SSTP before discharging the wastewater into a waterway. The Borneo Island of Sarawak is selected as the case study. Currently, there are only two SSTPs in Sarawak, namely the Matang SSTP and the Sibu SSTP, and they are both using SBR technology. Monthly effluent discharges from 2007 to 2011 in the Matang SSTP are used in this study. Cross-validation is performed using data from the Sibu SSTP from April 2011 to July 2012. Both chemical oxygen demand (COD) and total suspended solids (TSS) in the effluent were analysed in this study. The model was validated and tested before forecasting the future effluent performance. The CSA-based SSTP model was simulated using MATLAB 7.10. The root mean square error (RMSE), mean absolute percentage error (MAPE), and correction coefficient (R) were used as performance indexes. In this study, it was found that the proposed prediction model was successful up to 84 months for the COD and 109 months for the TSS. In conclusion, the proposed CSA-based SSTP prediction model is indeed beneficial as an engineering tool to forecast the long-run performance of the SSTP and in turn, prevents infringement of future environmental balance in other towns in Sarawak.
    Matched MeSH terms: Environmental Monitoring/methods*
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