Displaying publications 1 - 20 of 57 in total

  1. Zakaria MP, Okuda T, Takada H
    Mar Pollut Bull, 2001 Dec;42(12):1357-66.
    PMID: 11827123
    Malaysian coasts are subjected to various threats of petroleum pollution including routine and accidental oil spill from tankers, spillage of crude oils from inland and off-shore oil fields, and run-off from land-based human activities. Due to its strategic location, the Straits of Malacca serves as a major shipping lane. This paper expands the utility of biomarker compounds, hopanes, in identifying the source of tar-balls stranded on Malaysian coasts. 20 tar-ball samples collected from the east and west coast were analyzed for hopanes and polycyclic aromatic hydrocarbons (PAHs). Four of the 13 tar-ball samples collected from the west coast of Peninsular Malaysia were identified as the Middle East crude oil (MECO) based on their biomarker signatures, suggesting tanker-derived sources significantly contributing the petroleum pollution in the Straits of Malacca. The tar-balls found on the east coast seem to originate from the offshore oil platforms in the South China Sea. The presence of South East Asian crude oil (SEACO) tar-balls on the west coast carry several plausible explanations. Some of the tar-balls could have been transported via sea currents from the east coast. The tankers carrying SEACO to other countries could have accidentally spilt the oil as well. Furthermore, discharge of tank washings and ballast water from the tankers were suggested based on the abundance in higher molecular weight n-alkanes and the absence of unresolved complex mixture (UCM) in the tar-ball samples. The other possibilities are that the tar-balls may have been originated from the Sumatran oil fields and spillage of domestic oil from oil refineries in Port Dickson and Malacca. The results of PAHs analysis suggest that all the tar-ball samples have undergone various extent of weathering through evaporation, dissolution and photooxidation.
  2. Lim WY, Aris AZ, Zakaria MP
    ScientificWorldJournal, 2012;2012:652150.
    PMID: 22919346 DOI: 10.1100/2012/652150
    This paper determines the controlling factors that influence the metals' behavior water-sediment interaction facies and distribution of elemental content ((75)As, (111)Cd, (59)Co, (52)Cr, (60)Ni, and (208)Pb) in water and sediment samples in order to assess the metal pollution status in the Langat River. A total of 90 water and sediment samples were collected simultaneously in triplicate at 30 sampling stations. Selected metals were analyzed using ICP-MS, and the metals' concentration varied among stations. Metal concentrations of water ranged between 0.08-24.71 μg/L for As, <0.01-0.53 μg/L for Cd, 0.06-6.22 μg/L for Co, 0.32-4.67 μg/L for Cr, 0.80-24.72 μg/L for Ni, and <0.005-6.99 μg/L for Pb. Meanwhile, for sediment, it ranged between 4.47-30.04 mg/kg for As, 0.02-0.18 mg/kg for Cd, 0.87-4.66 mg/kg for Co, 4.31-29.04 mg/kg for Cr, 2.33-8.25 mg/kg for Ni and 5.57-55.71 mg/kg for Pb. The average concentration of studied metals in the water was lower than the Malaysian National Standard for Drinking Water Quality proposed by the Ministry of Health. The average concentration for As in sediment was exceeding ISQG standards as proposed by the Canadian Sediment Quality Guidelines. Statistical analyses revealed that certain metals (As, Co, Ni, and Pb) were generally influenced by pH and conductivity. These results are important when making crucial decisions in determining potential hazardous levels of these metals toward humans.
  3. Yap CK, Shahbazi A, Zakaria MP
    Bull Environ Contam Toxicol, 2012 Dec;89(6):1205-10.
    PMID: 23052577 DOI: 10.1007/s00128-012-0838-x
    In this study, the ranges of pollutants found in the soft tissues of Perna viridis collected from Kg. Masai and Kg. Sg. Melayu, both located in the Straits of Johore, were 0.85-1.58 μg/g dry weight (dw) for Cd, 5.52-12.2 μg/g dw for Cu, 5.66-8.93 μg/g dw for Ni and 63.4-72.3 μg/g dw for Zn, and 36.4-244 ng/g dry weight for ∑PAHs. Significantly (p < 0.05) higher concentrations of Cd, Cu, Ni, Zn and ∑PAHs in the mussels were found in the water of a seaport site at Kg. Masai than a non-seaport site at Kg. Sg. Melayu population. The ratios of low molecular weight/high molecular weight hydrocarbons (2.94-3.42) and fluoranthene/pyrene (0.43-0.45) in mussels from both sites indicated the origin of the PAHs to be mainly petrogenic. This study has demonstrated the utility of using the soft tissues of P. viridis as a biomonitor of PAH contamination and bioavailability in the coastal waters of Peninsular Malaysia.
  4. Keshavarzifard M, Zakaria MP, Hwai TS
    Environ Geochem Health, 2017 Jun;39(3):591-610.
    PMID: 27216263 DOI: 10.1007/s10653-016-9835-z
    The bioaccumulation and bioavailability of polycyclic aromatic hydrocarbons (PAHs) were characterized in sediment and Paphia undulata (short-neck clam) from six mudflat areas in the west coasts of Peninsular Malaysia. The concentrations of total PAHs varied from 357.1 to 6257.1 and 179.9 ± 7.6 to 1657.5 ± 53.9 ng g -1 dry weight in sediment and short-neck clam samples, respectively. PAHs can be classified as moderate to very high level of pollution in sediments and moderate to high level of pollution in short-neck clams. The diagnostic ratios of individual PAHs and principal component analysis indicate both petrogenic and pyrogenic sources with significant dominance of pyrogenic source. The first PAHs biota-sediment accumulation factors and relative biota-sediment accumulation factors data for short-neck clam were obtained in this study, indicating a preferential accumulation of lower molecular weight PAHs. Evaluation of PAH levels in sediments and short-neck clams indicates that short-neck clam could be introduced as a good biomonitor in mudflats. The results also demonstrated that under environmental conditions, the sedimentary load of hydrocarbons appears to be one of the factors controlling their bioavailability to biota.
  5. Keshavarzifard M, Zakaria MP, Sharifi R
    Arch Environ Contam Toxicol, 2017 Oct;73(3):474-487.
    PMID: 28497299 DOI: 10.1007/s00244-017-0410-0
    The distribution, sources, and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediment and the edible tissue of short-neck clam (Paphia undulata) from mudflat ecosystem in the west coast of Malaysia were investigated. The concentrations of ∑16 PAHs varied from 347.05 to 6207.5 and 179.32 to 1657.5 ng g-1 in sediment and short-neck clam samples, respectively. The calculations of mean PEL quotients (mean-PELQs) showed that the ecological risk of PAHs in the sediment samples was low to moderate-high level, whereas the total health risk through ingestion and dermal contact was considerably high. The PAHs biota sediment accumulation factors data for short-neck clam were obtained in this study, indicating a preferential accumulation of lower molecular weight PAHs. The source apportionment of PAHs in sediment using positive matrix factorization model indicated that the highest contribution to the PAHs was from diesel emissions (30.38%) followed by oil and oil derivate and incomplete coal combustion (23.06%), vehicular emissions (16.43%), wood combustion (15.93%), and natural gas combustion (14.2%). A preliminary evaluation of human health risk using chronic daily intake, hazard index, benzo[a]pyrene-equivalent (BaPeq) concentration, and the incremental lifetime cancer risk indicated that PAHs in short-neck clam would induce potential carcinogenic effects in the consumers.
  6. Vaezzadeh V, Zakaria MP, Bong CW
    Mar Pollut Bull, 2017 Nov 15;124(1):33-42.
    PMID: 28693809 DOI: 10.1016/j.marpolbul.2017.07.008
    The Straits of Malacca is one of the world's busiest shipping routes where frequent oil spills occur. Rapid development in the west coast of Peninsular Malaysia is the other major source of petroleum pollution in this narrow waterway. In order to identify occurrence and origin of hydrocarbons in the Straits, mangrove oysters (Crassostrea belcheri) were collected from five sampling locations and analysed for n-alkanes and biomarkers. Soxhlet apparatus and two step column chromatography were used for extraction, purification and fractionation of the oysters. Petroleum origin n-alkanes were detected in majority of the sampling locations which is indicative of anthropogenic activities in this region. Using source and maturity diagnostic ratios for hopanes revealed used crankcase oil as the main source of petroleum hydrocarbons in oysters from all sampling locations except for the Pulau Merambong where signature of South East Asia crude oil (SEACO) was detected.
  7. Alkhadher SAA, Suratman S, Zakaria MP
    Environ Monit Assess, 2023 May 24;195(6):720.
    PMID: 37222826 DOI: 10.1007/s10661-023-11310-w
    One of the molecular chemical markers used to identify anthropogenic inputs is linear alkylbenzenes (LABs) that cause serious impacts in the bays and coastal ecosystems. The surface sediments samples collected from the East Malaysia, including Brunei bay to estimate the LABs concentration and distribution as molecular markers of anthropogenic indicators. Gas chromatography-mass spectrometry (GC-MS) was used after purification, fractionation the hydrocarbons in the sediment samples to identify the sources of LABs. The analysis of variance (ANOVA) and Pearson correlation coefficient were applied to analyze the difference between sampling stations' significance at p 
  8. Karami A, Teh SJ, Zakaria MP, Courtenay SC
    J Environ Sci (China), 2015 Dec;38:95-102.
    PMID: 26702972 DOI: 10.1016/j.jes.2015.05.009
    Naturally-occurring and artificially-induced polyploids have been documented in various fish species but to date no comparison has been reported of the impacts of ploidy on fish biomarker responses to organic pollutants. This study describes effects of ploidy, gender, and dose on biliary fluorescent aromatic compound (FAC) concentrations, hepatic ethoxyresorufin-O-deethylase (EROD) and glutathione S-transferase (GST) activities in one of the most commonly cultured warm-water species, the African catfish Clarias gariepinus. Recently matured male and female diploid and triploid fish were intraperitoneally (i.p.) injected with 0, 5 or 25mg/kg benzo[a]pyrene (BaP) and liver and gallbladder were sampled 48hr later. No significant differences were found between ploidies in bile concentrations of 7,8 dihydrodiolbenzo[a]pyrene (7,8D BaP), 1-hydroxybenzo[a]pyrene (1-OH BaP) or 3-hydroxybenzo[a]pyrene (3-OH BaP). However, concentrations of the biliary FACs did differ between males and females at different dose of injection with generally higher concentrations in females at the low dose of BaP and higher concentrations in males at the higher BaP concentration. Hepatic EROD activity did not exhibit gender-dependent difference, whereas it was significantly higher in triploids than diploids. GST activities were not significantly influenced by any of the tested factors. This work advanced our understanding of the role of ploidy, gender, and dose in biotransformation of pollutants in fish.
  9. Ho YB, Zakaria MP, Latif PA, Saari N
    Sci Total Environ, 2014 Aug 1;488-489:261-7.
    PMID: 24836135 DOI: 10.1016/j.scitotenv.2014.04.109
    Repeated applications of animal manure as fertilizer are normal agricultural practices that may release veterinary antibiotics and hormones into the environment from treated animals. Broiler manure samples and their respective manure-amended agricultural soil samples were collected in selected locations in the states of Selangor, Negeri Sembilan and Melaka in Malaysia to identify and quantify veterinary antibiotic and hormone residues in the environment. The samples were analyzed using ultrasonic extraction followed by solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The broiler manure samples were found to be contaminated with at least six target analytes, namely, doxycycline, enrofloxacin, flumequine, norfloxacin, trimethoprim and tylosin. These analytes were detected in broiler manure samples with maximum concentrations reaching up to 78,516 μg kg(-1) dry weight (DW) (doxycycline). For manure-amended agricultural soil samples, doxycycline and enrofloxacin residues were detected in every soil sample. The maximum concentration of antibiotic detected in soil was 1331 μg kg(-1) DW (flumequine). The occurrence of antibiotics and hormones in animal manure at high concentration poses a risk of contaminating agricultural soil via fertilization with animal manure. Some physico-chemical parameters such as pH, total organic carbon (TOC) and metal content played a considerable role in the fate of the target veterinary antibiotics and progesterone in the environment. It was suggested that these parameters can affect the adsorption of pharmaceuticals to solid environmental matrices.
  10. Mirsadeghi SA, Zakaria MP, Yap CK, Gobas F
    Sci Total Environ, 2013 Jun 1;454-455:584-97.
    PMID: 23583984 DOI: 10.1016/j.scitotenv.2013.03.001
    The spatial distribution of 19 polycyclic aromatic hydrocarbons (tPAHs) was quantified in aquacultures located in intertidal mudflats of the west coast of Peninsular Malaysia in order to investigate bioaccumulation of PAH in blood cockles, Anadara granosa (A. granosa). Fifty-four samples from environmental matrices and A. granosa were collected. The sampling locations were representative of a remote area as well as PAH-polluted areas. The relationship of increased background levels of PAH to anthropogenic PAH sources in the environment and their effects on bioaccumulation levels of A. granosa are investigated in this study. The levels of PAH in the most polluted station were found to be up to ten-fold higher than in remote areas in blood cockle. These high concentrations of PAHs reflected background contamination, which originates from distant airborne and waterborne transportation of contaminated particles. The fraction and source identification of PAHs, based on fate and transport considerations, showed a mix of petrogenic and pyrogenic sources. The relative biota-sediment accumulation factors (RBSAF), relative bioaccumulation factors from filtered water (RBAFw), and from suspended particulate matter (SPM) (RBAFSP) showed higher bioaccumulations of the lower molecular weight of PAHs (LMWs) in all stations, except Kuala Juru, which showed higher bioaccumulation of the higher molecular weight of PAHs (HMWs). Calculations of bioaccumulation factors showed that blood cockle can accumulate PAHs from sediment as well as water samples, based on the physico-chemical characteristics of habitat and behaviour of blood cockles. Correlations among concentrations of PAHs in water, SPM, sediment and A. granosa at the same sites were also found. Identification of PAH levels in different matrices showed that A. granosa can be used as a good biomonitor for LMW of PAHs and tPAHs in mudflats. Considering the toxicity and carcinogenicity of PAHs, the bioaccumulation by blood cockles are a potential hazard for both blood cockles and their consumers.
  11. Ho YB, Zakaria MP, Latif PA, Saari N
    J Chromatogr A, 2012 Nov 2;1262:160-8.
    PMID: 23026257 DOI: 10.1016/j.chroma.2012.09.024
    A multi-residue analytical method was developed to quantify nine antibiotics and one hormone in soil, broiler manure and manure compost. The developed method was based on ultrasonic extraction with MeOH:ACN:EDTA:McIlvaine buffer, solid phase extraction (SPE) using HLB (3 cc/60 mg) cartridge, followed by instrumental analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with 25 min total run time. It was validated and tested on soil, broiler manure and manure compost samples and showed that the method is able to simultaneously detect and quantify the target analytes with good selectivity and sensitivity. The developed method was linear in a concentration range from its instrumental quantification limit (IQL) to 500 ng/mL, with correlation coefficients higher than 0.999. The overall method performance was good for the majority of the analytes, with recoveries range from 63% to 121% in all the sample matrices. The method quantification limit (MQL) for the 10 target analytes in the soil, broiler manure and manure compost samples were 2-10, 3-16 and 5-15 μg/kg dry weight (DW), respectively. The method has also included tilmicosin, an antibiotic known to be reported in the environment for the first time. The developed method was then applied on broiler manure samples and its relative manure amended agricultural soil samples to identify and quantify veterinary antibiotic and hormone residues in the environment. These analytes were detected in broiler manure and soil samples, with maximum concentrations reaching up to 78516.1 μg/kg DW (doxycycline) and 1331.4 μg/kg DW (flumequine), respectively. The results showed that the method can potentially be adopted for the analysis of veterinary antibiotic and hormone wastes in solid environmental matrices.
  12. Adnan NH, Zakaria MP, Juahir H, Ali MM
    J Environ Sci (China), 2012;24(9):1600-8.
    PMID: 23520867
    The Langat River in Malaysia has been experiencing anthropogenic input from urban, rural and industrial activities for many years. Sewage contamination, possibly originating from the greater than three million inhabitants of the Langat River Basin, were examined. Sediment samples from 22 stations (SL01-SL22) along the Langat River were collected, extracted and analysed by GC-MS. Six different sterols were identified and quantified. The highest sterol concentration was found at station SL02 (618.29 ng/g dry weight), which situated in the Balak River whereas the other sediment samples ranged between 11.60 and 446.52 ng/g dry weight. Sterol ratios were used to identify sources, occurrence and partitioning of faecal matter in sediments and majority of the ratios clearly demonstrated that sewage contamination was occurring at most stations in the Langat River. A multivariate statistical analysis was used in conjunction with a combination of biomarkers to better understand the data that clearly separated the compounds. Most sediments of the Langat River were found to contain low to mid-range sewage contamination with some containing 'significant' levels of contamination. This is the first report on sewage pollution in the Langat River based on a combination of biomarker and multivariate statistical approaches that will establish a new standard for sewage detection using faecal sterols.
  13. Al-Odaini NA, Zakaria MP, Yaziz MI, Surif S
    J Chromatogr A, 2010 Oct 29;1217(44):6791-806.
    PMID: 20851398 DOI: 10.1016/j.chroma.2010.08.033
    Pollutants such as human pharmaceuticals and synthetic hormones that are not covered by environmental legislation have increasingly become important emerging aquatic contaminants. This paper reports the development of a sensitive and selective multi-residue method for simultaneous determination and quantification of 23 pharmaceuticals and synthetic hormones from different therapeutic classes in water samples. Target pharmaceuticals include anti-diabetic, antihypertensive, hypolipidemic agents, β2-adrenergic receptor agonist, antihistamine, analgesic and sex hormones. The developed method is based on solid phase extraction (SPE) followed by instrumental analysis using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) with 30 min total run time. River water samples (150 mL) and (sewage treatment plant) STP effluents (100 mL) adjusted to pH 2, were loaded into MCX (3 cm(3), 60 mg) cartridge and eluted with four different reagents for maximum recovery. Quantification was achieved by using eight isotopically labeled internal standards (I.S.) that effectively correct for losses during sample preparation and matrix effects during LC-ESI-MS/MS analysis. Good recoveries higher than 70% were obtained for most of target analytes in all matrices. Method detection limit (MDL) ranged from 0.2 to 281 ng/L. The developed method was applied to determine the levels of target analytes in various samples, including river water and STP effluents. Among the tested emerging pollutants, chlorothiazide was found at the highest level, with concentrations reaching up to 865 ng/L in STP effluent, and 182 ng/L in river water.
  14. Ho YB, Zakaria MP, Latif PA, Saari N
    Bioresour Technol, 2013 Mar;131:476-84.
    PMID: 23384781 DOI: 10.1016/j.biortech.2012.12.194
    The fate of nine veterinary antibiotics and one hormone in broiler manure during 40 days of composting was investigated. Results showed that composting can significantly reduce the concentration of veterinary antibiotics and hormone in broiler manure, making application of the post-compost manure safer for soil application. More than 99% of the nine antibiotics and one hormone involved in this study were removed from the manure during 40 days of composting. The target antibiotics and hormone showed short half-life in broiler manure composting, ranging from 1.3 to 3.8 days. The relationship between the physico-chemical properties of soil, manure and manure compost and its veterinary antibiotic and hormone concentration was statistically evaluated by Pearson correlation matrix. The concentration of veterinary antibiotics and hormone in manure compost was suggested to be affected by physico-chemical properties such as pH, temperature, total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP) and metal contents.
  15. Anyika C, Abdul Majid Z, Ibrahim Z, Zakaria MP, Yahya A
    Environ Sci Pollut Res Int, 2015 Mar;22(5):3314-41.
    PMID: 25345923 DOI: 10.1007/s11356-014-3719-5
    Amending polycyclic aromatic hydrocarbon (PAH)-contaminated soils with biochar may be cheaper and environmentally friendly than other forms of organic materials. This has led to numerous studies on the use of biochar to either bind or stimulate the microbial degradation of organic compounds in soils. However, very little or no attention have been paid to the fact that biochars can give simultaneous impact on PAH fate processes, such as volatilization, sorption and biodegradation. In this review, we raised and considered the following questions: How does biochar affect microbes and microbial activities in the soil? What are the effects of adding biochar on sorption of PAHs? What are the effects of adding biochar on degradation of PAHs? What are the factors that we can manipulate in the laboratory to enhance the capability of biochars to degrade PAHs? A triphasic concept of how biochar can give simultaneous impact on PAH fate processes in soils was proposed, which involves rapid PAH sorption into biochar, subsequent desorption and modification of soil physicochemical properties by biochar, which in turn stimulates microbial degradation of the desorbed PAHs. It is anticipated that biochar can give simultaneous impact on PAH fate processes in soils.
  16. Thomes MW, Vaezzadeh V, Zakaria MP, Bong CW
    Environ Sci Pollut Res Int, 2019 Nov;26(31):32672-32673.
    PMID: 31520373 DOI: 10.1007/s11356-019-06373-7
    The original publication of this paper contains a mistake. The correct image of figure 2 is shown in this paper.
  17. Thomes MW, Vaezzadeh V, Zakaria MP, Bong CW
    Environ Sci Pollut Res Int, 2019 Nov;26(31):31555-31580.
    PMID: 31440968 DOI: 10.1007/s11356-019-05936-y
    Southeast Asia has undergone rapid developments in terms of urbanization, economic and population growth. The progress in sewerage treatment infrastructure has not kept pace with such developments. The inadequacy and inefficiency of sewerage systems has prompted the release of untreated sewage into the aquatic environment of Southeast Asia causing many waterborne illnesses since surface water is utilized for recreational, agricultural and aquaculture purposes and, above all, as a source of water intake in Southeast Asia. This paper will review the current data on molecular markers of sewage pollution including sterols and linear alkylbenzenes (LABs) in Southeast Asian aquatic environment to clarify the state of sewage pollution and the competence of sewage treatment plants (STPs) in this area. Despite the importance of sewage pollution research in the region, the number of studies using molecular markers to trace the sources of sewage pollution is limited. So far, indicators of sewage pollution have been investigated in aquatic environments of Indonesia, Vietnam, Malaysia, the Philippines, Thailand, Cambodia and Brunei among Southeast Asian countries. The concentrations and diagnostic ratios of faecal sterols and LABs show the release of untreated and primary treated urban waste into water bodies of these countries. Further studies are required to fill the data gaps in Southeast Asia and come to a better understanding of the trends of sewage pollution in this part of the world. Graphical abstract.
  18. Othman AR, Abdullah N, Ahmad S, Ismail IS, Zakaria MP
    PMID: 25652309 DOI: 10.1186/s12906-015-0528-4
    BACKGROUND: The Jatropha curcas plant or locally known as "Pokok Jarak" has been widely used in traditional medical applications. This plant is used to treat various conditions such as arthritis, gout, jaundice, wound and inflammation. However, the nature of compounds involved has not been well documented. Hence, this study was conducted to investigate the anti-inflammatory activity of different parts of J. curcas plant and to identify the active compounds involved.
    METHODS: In this study, methanol (80%) extraction of four different parts (leaves, fruits, stem and root) of J. curcas plant was carried out. Phenolic content of each part was determined by using Folin-Ciocalteau reagent. Gallic acid was used as the phenol standard. Each plant part was screened for anti-inflammatory activity using cultured macrophage RAW 264.7 cells. The active plant part was then partitioned with hexane, chloroform, ethyl acetate and water. Each partition was again screened for anti-inflammatory activity. The active partition was then fractionated using an open column chromatography system. Single spots isolated from column chromatography were assayed for anti-inflammatory and cytotoxicity activities. Spots that showed activity were subjected to gas chromatography mass spectrophotometry (GC-MS) analysis for identification of active metabolites.
    RESULTS: The hexane partition from root extract showed the highest anti-inflammatory activity. However, it also showed high cytotoxicity towards RAW 264.7 cells at 1 mg/mL. Fractionation process using column chromatography showed five spots. Two spots labeled as H-4 and H-5 possessed anti-inflammatory activity, without cytotoxicity activity. Analysis of both spots by GC-MS showed the presence of hexadecanoic acid methyl ester, octadecanoic acid methyl ester and octadecanoic acid.
    CONCLUSION: This finding suggests that hexadecanoic acid methyl ester, octadecanoic acid methyl ester and octadecanoic acid could be responsible for the anti-inflammatory activity of the J. curcas root extract.
  19. Fakhru'l-Razi A, Peyda M, Ab Karim Ghani WA, Abidin ZZ, Zakaria MP, Moeini H
    Biotechnol Prog, 2014 Jul-Aug;30(4):797-805.
    PMID: 24692323 DOI: 10.1002/btpr.1911
    In this work, crude oil biodegradation has been optimized in a solid-liquid two phase partitioning bioreactor (TPPB) by applying a response surface methodology based d-optimal design. Three key factors including phase ratio, substrate concentration in solid organic phase, and sodium chloride concentration in aqueous phase were taken as independent variables, while the efficiency of the biodegradation of absorbed crude oil on polymer beads was considered to be the dependent variable. Commercial thermoplastic polyurethane (Desmopan®) was used as the solid phase in the TPPB. The designed experiments were carried out batch wise using a mixed acclimatized bacterial consortium. Optimum combinations of key factors with a statistically significant cubic model were used to maximize biodegradation in the TPPB. The validity of the model was successfully verified by the good agreement between the model-predicted and experimental results. When applying the optimum parameters, gas chromatography-mass spectrometry showed a significant reduction in n-alkanes and low molecular weight polycyclic aromatic hydrocarbons. This consequently highlights the practical applicability of TPPB in crude oil biodegradation.
  20. Shafie NA, Aris AZ, Zakaria MP, Haris H, Lim WY, Isa NM
    PMID: 23043340 DOI: 10.1080/10934529.2012.717810
    An investigative study was carried out in Langat River to determine the heavy metal pollution in the sediment with 22 sampling stations selected for the collection of sediment samples. The sediment samples were digested and analyzed for extractable metal ((48)Cd, (29)Cu, (30)Zn, (33)As, (82)Pb) using the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Parameters, such as pH, Eh, electrical conductivity (EC), salinity, cation exchange capacity (CEC) and loss on ignition (LOI) were also determined. The assessment of heavy metal pollution was derived using the enrichment factors (EF) and geoaccumulation index (I(geo)). This study revealed that the sediment is predominantly by As > Cd > Pb > Zn > Cu. As recorded the highest EF value at 187.45 followed by Cd (100.59), Pb (20.32), Zn (12.42) and Cu (3.46). This is similar to the I(geo), which indicates that the highest level goes to As (2.2), exhibits moderately polluted. Meanwhile, Cd recorded 1.8 and Pb (0.23), which illustrates that both of these elements vary from unpolluted to moderately polluted. The Cu and Zn levels are below 0, which demonstrates background concentrations. The findings are expected to update the current status of the heavy metal pollution as well as creating awareness concerning the security of the river water as a drinking water source.
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links