Displaying publications 21 - 40 of 198 in total

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  1. Khan AM, Bakar NKA, Bakar AFA, Ashraf MA
    Environ Sci Pollut Res Int, 2017 Oct;24(29):22764-22789.
    PMID: 27722986 DOI: 10.1007/s11356-016-7427-1
    Rare earths (RE), chemically uniform group of elements due to similar physicochemical behavior, are termed as lanthanides. Natural occurrence depends on the geological circumstances and has been of long interest for geologist as tools for further scientific research into the region of ores, rocks, and oceanic water. The review paper mainly focuses to provide scientific literature about rare earth elements (REEs) with potential environmental and health effects in understanding the research. This is the initial review of RE speciation and bioavailability with current initiative toward development needs and research perceptive. In this paper, we have also discussed mineralogy, extraction, geochemistry, analytical methods of rare earth elements. In this study, REEs with their transformation and vertical distribution in different environments such as fresh and seawater, sediments, soil, weathering, transport, and solubility have been reported with most recent literature along key methods of findings. Speciation and bioavailability have been discussed in detail with special emphasis on soil, plant, and aquatic ecosystems and their impacts on the environment. This review shows that REE gained more importance in last few years due to their detrimental effects on living organisms, so their speciation, bioavailability, and composition are much more important to evaluate their health risks and are discussed thoroughly as well.
    Matched MeSH terms: Seawater
  2. Ismail A, Toriman ME, Juahir H, Zain SM, Habir NL, Retnam A, et al.
    Mar Pollut Bull, 2016 May 15;106(1-2):292-300.
    PMID: 27001716 DOI: 10.1016/j.marpolbul.2015.10.019
    This study presents the determination of the spatial variation and source identification of heavy metal pollution in surface water along the Straits of Malacca using several chemometric techniques. Clustering and discrimination of heavy metal compounds in surface water into two groups (northern and southern regions) are observed according to level of concentrations via the application of chemometric techniques. Principal component analysis (PCA) demonstrates that Cu and Cr dominate the source apportionment in northern region with a total variance of 57.62% and is identified with mining and shipping activities. These are the major contamination contributors in the Straits. Land-based pollution originating from vehicular emission with a total variance of 59.43% is attributed to the high level of Pb concentration in the southern region. The results revealed that one state representing each cluster (northern and southern regions) is significant as the main location for investigating heavy metal concentration in the Straits of Malacca which would save monitoring cost and time.

    CAPSULE: The monitoring of spatial variation and source of heavy metals pollution at the northern and southern regions of the Straits of Malacca, Malaysia, using chemometric analysis.

    Matched MeSH terms: Seawater/chemistry*
  3. 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: Seawater/chemistry
  4. Ali HR, Arifin MM, Sheikh MA, Mohamed Shazili NA, Bachok Z
    Mar Pollut Bull, 2013 May 15;70(1-2):253-7.
    PMID: 23490347 DOI: 10.1016/j.marpolbul.2013.02.024
    Emerging booster biocides contamination raises particular attention in the marine ecosystem health. This study provides the baseline data on the occurrence of Irgarol-1051 (2-methylthio-4-tert-butylamino-6-cyclopropylamiono-s-triazine) in the selected coastal water around Malaysia. The maximum detected concentration of Irgarol was 2021 ng/L at Klang West, commercial and cargo port. Coral reef Islands (Redang and Bidong) were relatively less contaminated compared to other coastal areas. The temporal variation revealed that only 1% of 28 stations sampled on November, 2011 was above the environmental risk limit of 24 ng/L as suggested by Dutch Authorities, while in January and April, 2012; 46% and 92% of the stations were above the limit respectively. The present findings demonstrate the wide detection of novel antifouling materials Irgarol-1051 which advocates the need for proper monitoring and conservation strategies for the coastal resources.
    Matched MeSH terms: Seawater/chemistry*
  5. Khalik WMAWM, Ibrahim YS, Tuan Anuar S, Govindasamy S, Baharuddin NF
    Mar Pollut Bull, 2018 Oct;135:451-457.
    PMID: 30301058 DOI: 10.1016/j.marpolbul.2018.07.052
    The first report on the emergence of microplastic in Malaysian marine waters was documented in this study. Water samples were collected from two regions, namely Kuala Nerus and Kuantan port, as the representatives of different anthropogenic activities. Identification of microplastic was performed based on physical characteristics (colour, shape, density) and chemical characterisation (ATR-FTIR analysis) for a functional group of polymers. Fragment type, black or grey colour and high density (>1.02 g cm-3) of microplastic were the most prevalent characteristics found in both areas. Two principal components (density and colour) rendered explained about 95.3% (Kuantan) and 95.6% (Kuala Nerus) of the total variance. Six possible polymer materials were identified, namely polyester, polystyrene, polyamide, polyvinyl chloride, polypropylene, and polyethylene. The findings of the study provided good baseline information on marine debris issue in Malaysia.
    Matched MeSH terms: Seawater/analysis
  6. Abdulbari HA, Basheer EAM
    Sci Rep, 2019 08 29;9(1):12576.
    PMID: 31467344 DOI: 10.1038/s41598-019-49071-7
    Directional solvent extraction is one of the promising membrane-less seawater desalination method. This technique was not extensively investigated due the poor mixing and separation performances of its bench-scale system. It is believed that, overcoming these drawbacks is possible now with the rapid development of microfluidics technology that enabled high-precession micro mixing and separation. This work presents microfluidics chip for extracting and separating salt from seawater. The chip was designed with two sections for extraction and separation. In both sections, the liquids were separated using capillary channels perpendicular to the main stream. The main channels were designed to be 400 µm in width and 100 µm in height. Two streams inlets were introduced through a Y-junction containing octanoic acid as the organic phase and saltwater as the aqueous phase. The desalination performance was investigated at four different temperatures and five different solvent flow rates. Water product salinity was recorded to be as low as 0.056% (w/w) at 60 °C and 40 mL/h. A maximum water yield of 5.2% was achieved at 65 °C and 40 mL/h with a very low solvent residual (70 ppm). The chip mass transfer efficiency was recorded to be as high as 68% under similar conditions. The fabricated microfluidic desalination system showed a significant improvement in terms of water yield and separation efficiency over the conventional macroscale. The high performance of this microsystem resulted from its ability to achieve a high mixing efficiency and separate phases selectively and that will provide a good platform in the near future to develop small desalination kits for personal use.
    Matched MeSH terms: Seawater
  7. Rahman RN, Ghaza FM, Salleh AB, Basri M
    J Microbiol, 2006 Jun;44(3):354-9.
    PMID: 16820766
    This study examined the capacity of immobilized bacteria to degrade petroleum hydrocarbons. A mixture of hydrocarbon-degrading bacterial strains was immobilized in alginate and incubated in crude oil-contaminated artificial seawater (ASW). Analysis of hydrocarbon residues following a 30-day incubation period demonstrated that the biodegradation capacity of the microorganisms was not compromised by the immobilization. Removal of n-alkanes was similar in immobilized cells and control cells. To test reusability, the immobilized bacteria were incubated for sequential increments of 30 days. No decline in biodegradation capacity of the immobilized consortium of bacterial cells was noted over its repeated use. We conclude that immobilized hydrocarbon-degrading bacteria represent a promising application in the bioremediation of hydrocarbon-contaminated areas.
    Matched MeSH terms: Seawater/microbiology*
  8. Ab Lah R, Kelaher BP, Bucher D, Benkendorff K
    Mar Environ Res, 2018 Oct;141:100-108.
    PMID: 30119918 DOI: 10.1016/j.marenvres.2018.08.009
    Rising levels of atmospheric carbon dioxide are driving ocean warming and acidification. This could cause stress resulting in decreases in nutritional quality of marine species for human consumption, if environmental changes go beyond the optimal range for harvested species. To evaluate this, we used ambient and near-future elevated temperatures and pCO2 to assess impacts on the proximate nutritional composition (moisture, ash, protein, and lipids), fatty acids and trace elements of the foot tissue of Turbo militaris, a commercially harvested marine snail from south-eastern Australia. In a fully orthogonal design, the snails were exposed to ambient seawater conditions (22 ± 0.2 °C, pH 8.13 ± 0.01-450 μatm pCO2), ocean warming (25 ± 0.05 °C), pCO2 ocean acidification (pH 7.85 ± 0.02, ∼880 μatm pCO2) or a combination of both in controlled flow-through seawater mesocosms for 38 days. Moisture, ash, protein and total lipid content of the foot tissue in the turban snails was unaffected by ocean warming or acidification. However, ocean warming caused a reduction in healthful polyunsaturated fatty acids (PUFA) relative to saturated fatty acids (SFA). Under future warming and acidification conditions, there was a significant 3-5% decrease in n-3 fatty acids, which contributed to a decrease in the n-3/n-6 fatty acid ratio. The decrease in n-3 PUFAs, particularly Eicopentanoic acid (EPA), is a major negative outcome from ocean warming, because higher n-3/n-6 ratios in seafood are desirable for human health. Furthermore, ocean warming was found to increase levels of zinc in the tissues. Calcium, iron, macroelements, microelements and the composition of toxic elements did not appear to be affected by ocean climate change. Overall, the major impact from ocean climate change on seafood quality is likely to be a decrease in healthy polyunsaturated fatty acids at higher temperatures.
    Matched MeSH terms: Seawater*
  9. Adiana G, Shazili NA, Marinah MA, Bidai J
    Environ Monit Assess, 2014 Jan;186(1):421-31.
    PMID: 23974537 DOI: 10.1007/s10661-013-3387-9
    Concentrations of trace metals in the South China Sea (SCS) were determined off the coast of Terengganu during the months of May and November 2007. The concentrations of dissolved and particulate metals were in the range of 0.019-0.194 μg/L and 50-365 μg/g, respectively, for cadmium (Cd), 0.05-0.45 μg/L and 38-3,570 μg/g for chromium (Cr), 0.05-3.54 μg/L and 21-1,947 μg/g for manganese (Mn), and 0.03-0.49 μg/L and 2-56,982 μg/g for lead (Pb). The order of mean log K D found was Cd > Cr > Pb > Mn. The study suggests that the primary sources of these metals are discharges from the rivers which drain into the SCS, in particular the Dungun River, which flows in close proximity to agricultural areas and petrochemical industries. During the northeast monsoon, levels of particulate metals in the bottom water samples near the shore were found to be much higher than during the dry season, the probable result of re-suspension of the metals from the bottom sediments.
    Matched MeSH terms: Seawater/chemistry
  10. Amin YM, Mahat RH, Nor RM, Khandaker MU, Takleef GH, Bradley DA
    Radiat Prot Dosimetry, 2013 Oct;156(4):475-80.
    PMID: 23584496 DOI: 10.1093/rpd/nct097
    The presence of natural radioactivity and (137)Cs has been investigated in fresh media obtained from South China Sea locations off the coast of peninsular Malaysia. The media include seafood, sea water and sediment. The samples were collected some weeks prior to the devastating 2011 Tōhoku earthquake and associated tsunami, the occurrence of which precipitated the Fukushima incident. All samples showed the presence of naturally occurring (226)Ra, (228)Ra and primordial (40)K, all at typically prevailing levels. The concentrations of natural radioactivity in molluscs were found to be greater than that of other marine life studied herein, the total activity ranging from 337 to 393 Bq kg(-1) dry weight. The total activity in sea water ranged from 15 to 88 Bq l(-1). Sediment samples obtained at deep sea locations more than 20 km offshore further revealed the presence of (137)Cs. The activity of (137)Cs varied from ND to 0.5 Bq kg(-1) dry weight, the activity increasing with offshore distance and depth. The activity concentrations presented herein should be considered useful in assessing the impact of any future radiological contamination to the marine environment.
    Matched MeSH terms: Seawater
  11. Teh L, Cabanban AS
    J Environ Manage, 2007 Dec;85(4):999-1008.
    PMID: 17204361
    A priori assessments of a site's biophysical and socio-economic capacity for accommodating tourism are less common than tourism impact studies. A priori evaluations can provide a contextual understanding of ecological, economic and socio-cultural forces, which shape the prospects for sustainable tourism development at the host destination, and can avert adverse impacts of tourism. We conduct an a priori assessment of the biophysical environment of Pulau Banggi, in the Malaysian state of Sabah for sustainable tourism development. We characterise baseline conditions of the island's marine biodiversity, seasonality, and infrastructure. We then evaluate how existing biophysical conditions will influence options for sustainable tourism development. In particular, we suggest conditions, if there are any, which constitute a limit to future tourism development in terms of compatibility for recreation and resilience to visitor impacts. We find that the biggest constraint is the lack of adequate water and sanitation infrastructure. Blast fishing, although occurring less than once per hour, can potentially destroy the major attraction for tourists. We conclude that while Pulau Banggi possesses natural qualities that are attractive for ecotourism, financial and institutional support must be made available to provide facilities and services that will enable local participation in environmental protection and enhance prospects for future sustainable tourism.
    Matched MeSH terms: Seawater/analysis*
  12. Tan WS, Yunos NY, Tan PW, Mohamad NI, Adrian TG, Yin WF, et al.
    Sensors (Basel), 2014;14(7):12104-13.
    PMID: 25006994 DOI: 10.3390/s140712104
    N-acylhomoserine lactones (AHL) plays roles as signal molecules in quorum sensing (QS) in most Gram-negative bacteria. QS regulates various physiological activities in relation with population density and concentration of signal molecules. With the aim of isolating marine water-borne bacteria that possess QS properties, we report here the preliminary screening of marine bacteria for AHL production using Chromobacterium violaceum CV026 as the AHL biosensor. Strain T33 was isolated based on preliminary AHL screening and further identified by using 16S rDNA sequence analysis as a member of the genus Vibrio closely related to Vibrio brasiliensis. The isolated Vibrio sp. strain T33 was confirmed to produce N-hexanoyl-L-homoserine lactone (C6-HSL) and N-(3-oxodecanoyl)-L-homoserine lactone (3-oxo-C10 HSL) through high resolution tandem mass spectrometry analysis. We demonstrated that this isolate formed biofilms which could be inhibited by catechin. To the best of our knowledge, this is the first report that documents the production of these AHLs by Vibrio brasiliensis strain T33.
    Matched MeSH terms: Seawater/microbiology*
  13. Chan XY, Arumugam R, Choo SW, Yin WF, Chan KG
    Genome Announc, 2013;1(4).
    PMID: 23950114 DOI: 10.1128/genomeA.00540-13
    Tropical seawater harbors a rich diversity of microorganisms as a result of its nutrient-rich environment, constant supply of sufficient sunlight, and warm climate. In this report, we present the complexity of the microbial diversity of the surface seawater of the Georgetown coast as determined using next-generation sequencing technology.
    Matched MeSH terms: Seawater
  14. Wong CS, Yin WF, Choo YM, Sam CK, Koh CL, Chan KG
    World J Microbiol Biotechnol, 2012 Feb;28(2):453-61.
    PMID: 22806840 DOI: 10.1007/s11274-011-0836-x
    A chemically defined medium called KGm medium was used to isolate from a sample of sea water a bacterial strain, MW3A, capable of using N-3-oxohexanoyl-L: -homoserine lactone as the sole carbon source. MW3A was clustered closely to Pseudomonas aeruginosa by 16S ribosomal DNA sequence analysis. It degraded both N-acylhomoserine lactones (AHLs) with a 3-oxo group substitution and, less preferably, AHLs with unsubstituted groups at C3 position in the acyl side chain, as determined by Rapid Resolution Liquid Chromatography. Its quiP and pvdQ homologue gene sequences showed high similarities to those of known acylases. Spent supernatant of MW3A harvested at 8-h post inoculation was shown to contain long-chain AHLs when assayed with the biosensor Escherichia coli [pSB1075], and specifically N-dodecanoyl-L: -homoserine lactone and N-3-oxotetradecanoyl-L: -homoserine lactone by high resolution mass spectrometry. Hence, we report here a novel marine P. aeruginosa strain MW3A possessing both quorum-quenching and quorum-sensing properties.
    Matched MeSH terms: Seawater/microbiology
  15. Chan XY, Chen JW, Adrian TG, Hong KW, Chang CY, Yin WF, et al.
    Genome Announc, 2017 Mar 30;5(13).
    PMID: 28360153 DOI: 10.1128/genomeA.00067-17
    Bacillus sp. is a Gram-positive bacterium that is commonly found in seawater. In this study, the genome of marine Bacillus sp. strain G3(2015) was sequenced using MiSeq. The fosfomycin resistant gene fosB was identified upon bacterial genome annotation.
    Matched MeSH terms: Seawater
  16. Chen CY, Nagarajan D, Cheah WY
    Bioresour Technol, 2018 Apr;253:1-7.
    PMID: 29328929 DOI: 10.1016/j.biortech.2017.12.102
    In this study, Nannochloropsis oceanica CY2 was grown in deep-sea water (DSW)-based medium in 5-L plastic bag-type photobioreactors (PBRs) for the autotrophic production of Eicosapentaenoic acid (EPA, 20:5n-3). EPA production of N. oceanica CY2 was stimulated when it was grown in 100% DSW amended with 1.5 g L-1 NaNO3, achieving a EPA content of 3.1% and a biomass concentration of 3.3 g L-1. An outdoor-simulated microalgae cultivation system was also conducted to validate the feasibility of outdoor cultivation of the CY2 strain in plastic bag-type PBRs. Using an inoculum size of 0.6 g/L, the biomass concentration in the PBR culture was 3.5 g L-1, while the EPA content and productivity reached a maximal level of 4.12% and 7.49 mg L-1 d-1, respectively. When the PBRs were operated on semi-batch mode, the EPA productivity could further increase to 9.9 mg L-1 d-1 with a stable EPA content of 4.1%.
    Matched MeSH terms: Seawater
  17. Ip YK, Randall DJ, Kok TK, Barzaghi C, Wright PA, Ballantyne JS, et al.
    J Exp Biol, 2004 Feb;207(Pt 5):787-801.
    PMID: 14747411
    Periophthalmodon schlosseri is an amphibious and obligatory air-breathing teleost, which is extremely tolerant to environmental ammonia. It actively excretes NH(4)(+) in ammonia loading conditions. For such a mechanism to operate efficaciously the fish must be able to prevent back flux of NH(3). P. schlosseri could lower the pH of 50 volumes (w/v) of 50% seawater in an artificial burrow from pH 8.2 to pH 7.4 in 1 day, and established an ambient ammonia concentration of 10 mmol l(-1) in 8 days. It could alter the rate of titratable acid efflux in response to ambient pH. The rate of net acid efflux (H(+) excretion) in P. schlosseri was pH-dependent, increasing in the order pH 6.0<7.0<8.0<8.5. Net acid flux in neutral or alkaline pH conditions was partially inhibited by bafilomycin, indicating the possible involvement of a V-type H(+)-ATPase. P. schlosseri could also increase the rate of H(+) excretion in response to the presence of ammonia in a neutral (pH 7.0) external medium. Increased H(+) excretion in P. schlosseri occurred in the head region where active excretion of NH(4)(+) took place. This would result in high concentrations of H(+) in the boundary water layer and prevent the dissociation of NH(4)(+), thus preventing a back flux of NH(3) through the branchial epithelia. P. schlosseri probably developed such an 'environmental ammonia detoxification' capability because of its unique behavior of burrow building in the mudflats and living therein in a limited volume of water. In addition, the skin of P. schlosseri had low permeability to NH(3). Using an Ussing-type apparatus with 10 mmol l(-1) NH(4)Cl and a 1 unit pH gradient (pH 8.0 to 7.0), the skin supported only a very small flux of NH(3) (0.0095 micromol cm(-2) min(-1)). Cholesterol content (4.5 micromol g(-1)) in the skin was high, which suggests low membrane fluidity. Phosphatidylcholine, which has a stabilizing effect on membranes, constituted almost 50% of the skin phospholipids, with phosphatidyleserine and phsophatidylethanolamine contributing only 13% and 15%, respectively. More importantly, P. schlosseri increased the cholesterol level (to 5.5 micromol g(-1)) and altered the fatty acid composition (increased total saturated fatty acid content) in its skin lipid after exposure to ammonia (30 mmol l(-1) at pH 7.0) for 6 days. These changes might lead to an even lower permeability to NH(3) in the skin, and reduced back diffusion of the actively excreted NH(4)(+) as NH(3) or the net influx of exogenous NH(3), under such conditions.
    Matched MeSH terms: Seawater/analysis*
  18. Thevarajoo S, Selvaratnam C, Goh KM, Hong KW, Chan XY, Chan KG, et al.
    Int J Syst Evol Microbiol, 2016 Sep;66(9):3662-3668.
    PMID: 27334651 DOI: 10.1099/ijsem.0.001248
    A Gram-staining-negative, aerobic, yellow-orange-pigmented, rod-shaped bacterium designated D-24T was isolated from seawater from sandy shoreline in Johor, Malaysia. The 16S rRNA gene sequence analysis revealed that strain D-24T is affiliated with the genus Vitellibacter. It shared more than 96 % sequence similarity with the types of some of the validly published species of the genus: Vitellibactervladivostokensis KMM 3516T (99.5 %), Vitellibactersoesokkakensis RSSK-12T (97.3 %), VitellibacterechinoideorumCC-CZW007T (96.9 %), VitellibacternionensisVBW088T (96.7 %) and Vitellibacteraestuarii JCM 15496T (96.3 %). DNA-DNA hybridization and genome-based analysis of average nucleotide identity (ANI) of strain D-24T versus V.vladivostokensisKMM 3516T exhibited values of 35.9±0.14 % and 89.26 %, respectively. Strain D-24T showed an even lower ANI value of 80.88 % with V. soesokkakensis RSSK-12T. The major menaquinone of strain D-24T was MK-6, and the predominant fatty acids were iso-C15 : 0 and iso-C17 : 0 3-OH. Strain D-24T contained major amounts of phosphatidylethanolamine, two lipids and two aminolipids, and a phosphoglycolipid that was different to that of other species of the genus Vitellibacter. The genomic DNA G+C content was 40.6 mol%. On the basis of phenotypic properties, DNA-DNA relatedness, ANI value and chemotaxonomic analyses, strain D-24T represents a novel species of the genus Vitellibacter, for which the name Vitellibacter aquimaris sp. nov. is proposed. The type strain is D-24T (=KCTC 42708T=DSM 101732T).
    Matched MeSH terms: Seawater/microbiology*
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