Displaying publications 1 - 20 of 30 in total

  1. Chow MF, Yusop Z
    Water Sci Technol, 2014;69(2):244-52.
    PMID: 24473291 DOI: 10.2166/wst.2013.574
    The characteristics of urban stormwater pollution in the tropics are still poorly understood. This issue is crucial to the tropical environment because its rainfall and runoff generation processes are so different from temperate regions. In this regard, a stormwater monitoring program was carried out at three urban catchments (e.g. residential, commercial and industrial) in the southern part of Peninsular Malaysia. A total of 51 storm events were collected at these three catchments. Samples were analyzed for total suspended solids, 5-day biochemical oxygen demand, chemical oxygen demand (COD), oil and grease, nitrate nitrogen, nitrite nitrogen, ammonia nitrogen (NH3-N), soluble reactive phosphorus and total phosphorus. Principal component analysis (PCA) and hierarchical cluster analysis were used to interpret the stormwater quality data for pattern recognition and identification of possible sources. The most likely sources of stormwater pollutants at the residential catchment were from surface soil and leachate of fertilizer from domestic lawns and gardens, whereas the most likely sources for the commercial catchment were from discharges of food waste and washing detergent. In the industrial catchment, the major sources of pollutants were discharges from workshops and factories. The PCA factors further revealed that COD and NH3-N were the major pollutants influencing the runoff quality in all three catchments.
  2. Nazahiyah R, Yusop Z, Abustan I
    Water Sci Technol, 2007;56(7):1-9.
    PMID: 17951862
    Sampling of urban runoff was carried out in a small catchment, which represents a residential area (3.34 ha) in Skudai, Johor. One hundred and seventeen runoff samples from ten storm events were analysed. Runoff quality showed large variations in concentrations during storms, especially for SS, BOD5 and COD. Concentrations of NO3-N, NO2-N, NH3-N, and P were also high. Lead (Pb) was also detected but the levels were low (<0.001 mg/L). In general, the river quality is badly polluted and falls in Class V based on the Malaysian Interim National Water Quality Standards. Event mean concentrations for all parameters were found to vary greatly between storms. The values (mg/L) were BOD5 (72), COD (325), SS (386), NO3-N (2.5), NO2-N (0.58), NH3-N (6.8), P (3.4), respectively. First flush phenomena were observed for BOD, COD, SS, NO3-N, NH3-N and P. The first 20-30% of the runoff volume evacuated between 20-59% BOD, 15-69% COD, 15-78% SS, 14-49% NO3-N, 14-19% NO2-N, 23-53% NH3-N and 23-43% P.
  3. Chow MF, Yusop Z, Mohamed M
    Water Sci Technol, 2011;63(6):1211-6.
    PMID: 21436558 DOI: 10.2166/wst.2011.360
    This paper examines the storm runoff quality from a commercial area in south Johor, Malaysia. Six storm events with a total of 68 storm runoff samples were analyzed. Event Mean Concentration (EMC) for all constituents analysed showed large inter-event variation. Site mean concentrations (SMC) for total suspended solids (TSS), oil and grease (O&G), biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrate-nitrogen (NO(3)-N), nitrite-nitrogen (NO(2)-N), ammonia-nitrogen (NH(3)-N), total phosphorus (Total P) and Soluble P are 261, 4.31, 74, 192, 1.5, 0.006, 1.9, 1.12 and 0.38 mg/L, respectively. The SMCs at the studied site are higher than those reported in many urban catchments. The mean baseflow concentrations were higher than the EMCs for COD, Soluble P, NH(3)-N, NO(3)-N, Total P and NO(2)-N. However, the reverse was observed for TSS and O&G. All pollutants showed the occurrence of first flush phenomenon with the highest strength was observed for TSS, COD and NH(3)-N.
  4. Yusop Z, Chan CH, Katimon A
    Water Sci Technol, 2007;56(8):41-8.
    PMID: 17978431
    Rainfall-runoff processes in a small oil palm catchment (8.2 ha) in Johor, Malaysia were examined. Storm hydrographs show rapid responses to rainfall with a short time to peak. The estimated initial hydrologic loss for the oil palm catchment is 5 mm. Despite the low initial loss, the catchment exhibits a high proportion of baseflow, approximately 54% of the total runoff. On an event basis, the stormflow response factor and runoff coefficient ranges from 0.003 to 0.21, and 0.02 to 0.44, respectively. Peakflow and stormflow volume were moderately correlated with rainfall. The hydrographs were satisfactorily modelled using the Hydrologic Engineering Centre-Hydrologic Modelling System (HEC-HMS). The efficiency indexes of the calibration and validation exercises are 0.81 and 0.82, respectively. Based on these preliminary findings, it could be suggested that an oil palm plantation would be able to serve reasonably well in regulating basic hydrological functions.
  5. Yakubu ML, Yusop Z, Yusof F
    ScientificWorldJournal, 2014;2014:361703.
    PMID: 25126597 DOI: 10.1155/2014/361703
    This paper presents the modelled raindrop size parameters in Skudai region of the Johor Bahru, western Malaysia. Presently, there is no model to forecast the characteristics of DSD in Malaysia, and this has an underpinning implication on wet weather pollution predictions. The climate of Skudai exhibits local variability in regional scale. This study established five different parametric expressions describing the rain rate of Skudai; these models are idiosyncratic to the climate of the region. Sophisticated equipment that converts sound to a relevant raindrop diameter is often too expensive and its cost sometimes overrides its attractiveness. In this study, a physical low-cost method was used to record the DSD of the study area. The Kaplan-Meier method was used to test the aptness of the data to exponential and lognormal distributions, which were subsequently used to formulate the parameterisation of the distributions. This research abrogates the concept of exclusive occurrence of convective storm in tropical regions and presented a new insight into their concurrence appearance.
  6. Chow MF, Yusop Z, Toriman ME
    Water Sci Technol, 2013;67(8):1822-31.
    PMID: 23579839 DOI: 10.2166/wst.2013.048
    Urbanization and frequent storms play important roles in increasing faecal bacteria pollution, especially for tropical urban catchments. However, only little information on the faecal bacteria levels from different land use types and the factors that influence bacteria concentrations is available. Thus, the objectives of this study were to quantify the levels and transport mechanism of faecal coliforms (FCs) from residential and commercial catchments. Stormwaters were sampled and the runoff flow rates were measured from both catchments during four storm events in Skudai, Malaysia. The samples were then analysed for FC, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS) and ammoniacal-nitrogen (NH3-N) concentrations. Intra-storm and inter-storm characteristics of FC bacteria were investigated in order to identify the level and transport pattern of FC. The commercial catchment showed significantly higher event mean concentration (EMC) of FC than the residential catchment. For the residential catchment, the highest bacterial concentrations occurred during the early part of stormwater runoff with peak concentrations usually preceding the peak flow. First flush effect was more prevalent at the residential catchment.
  7. Chow MF, Yusop Z, Shirazi SM
    Environ Monit Assess, 2013 Oct;185(10):8321-31.
    PMID: 23591675 DOI: 10.1007/s10661-013-3175-6
    Information on the pollution level and the influence of hydrologic regime on the stormwater pollutant loading in tropical urban areas are still scarce. More local data are still required because rainfall and runoff generation processes in tropical environment are very different from the temperate regions. This study investigated the extent of urban runoff pollution in residential, commercial, and industrial catchments in the south of Peninsular Malaysia. Stormwater samples and flow rate data were collected from 51 storm events. Samples were analyzed for total suspended solids, 5-day biochemical oxygen demand, chemical oxygen demand, oil and grease (O&G), nitrate nitrogen (NO3-N), nitrite nitrogen, ammonia nitrogen, soluble reactive phosphorus, total phosphorus (TP), and zinc (Zn). It was found that the event mean concentrations (EMCs) of pollutants varied greatly between storm characteristics and land uses. The results revealed that site EMCs for residential catchment were lower than the published data but higher for the commercial and industrial catchments. All rainfall variables were negatively correlated with EMCs of most pollutants except for antecedent dry days (ADD). This study reinforced the earlier findings on the importance of ADD for causing greater EMC values with exceptions for O&G, NO3-N, TP, and Zn. In contrast, the pollutant loadings are influenced primarily by rainfall depth, mean intensity, and max 5-min intensity in all the three catchments. Overall, ADD is an important variable in multiple linear regression models for predicting the EMC values in the tropical urban catchments.
  8. Ahmad UK, Ulang Z, Yusop Z, Fong TL
    Water Sci Technol, 2002;46(9):117-25.
    PMID: 12448460
    The complex nature of natural organic matter (NOM), and the impact of this matter on drinking water quality have necessitated the characterization studies of NOM. A fluorescence technique for the characterization of NOM in Malaysian river water is reported. Water samples from several river sampling sites were collected and concentrated using a low-pressure reverse osmosis (LPROM). Solid phase extraction (SPE) using C18 extraction cartridges were used to fractionate the water samples into humic and non-humic fractions. To differentiate and classify various types of humic substances, fluorescence was applied in emission, excitation and in synchronous-scan modes. A synchronous spectral profile was found to be able to differentiate humic and fulvic acids better than the emission or excitation spectra. Synchronous excitation spectra showed different spectral patterns for the water samples due to different origin. All water samples showed the presence of both fulvic and humic acids.
  9. Thanalechumi P, Mohd Yusoff AR, Yusop Z
    J Environ Sci Health B, 2019;54(4):294-302.
    PMID: 30729855 DOI: 10.1080/03601234.2018.1561057
    A newly developed electrochemical sensor for chlorothalonil based on nylon 6,6 film deposited onto screen printed electrode (SPE) with electrochemical modulation of pH at the electrode/solution interface was studied for the first time. Differential pulse cathodic stripping voltammetry (DPCSV) was used to carry out the electrochemical and analytical studies. Experimental parameters such as accumulation potential, initial potential, accumulation time and pH of Britton-Robinson buffer have been optimized. Chlorothalonil gave optimum analytical signal in a medium of 0.04 M Britton-Robinson buffer at pH 6.0. A well-defined reduction peak was observed, at Ep= -0.851 and -0.938 V vs. Ag/AgCl (3.0 M KCl) for both bare SPE and modified SPE, respectively. The peak currents of modified SPE were significantly increased as compared to bare SPE. At the modified SPE, a linear relationship between the peak current and chlorothalonil concentration was obtained in the range from 0.1 to 2.8 × 10-6 M with a detection limit of 1.53 × 10-8 M (S/N= 3). The practical applicability of the newly developed method has been demonstrated on analyses of real water samples. The newly developed sensor shows good reproducibility with RSD of 3.92%. The nylon 6,6 modified SPE showed itself as promising sensor with good selectivity for chlorothalonil determination.
  10. Thanalechumi P, Mohd Yusoff AR, Yusop Z
    J Pestic Sci, 2017 May 20;42(2):39-44.
    PMID: 30363139 DOI: 10.1584/jpestics.D16-086
    The voltammetric determination of metsulfuron-methyl, a type of pesticide, was investigated on a hanging mercury drop electrode using a differential pulse cathodic stripping voltammetry technique. The experimental parameters, such as the pH of the Britton-Robinson buffer, accumulation time, accumulation potential and initial potential were optimized for the metsulfuron-methyl determination. A well-defined reduction peak was observed at pH 2.0 to 4.0 in the potential range of -0.75 to -1.0 V. The pH of 2.0 was chosen as the optimum pH due to a good stripping signal of the reduction peak. There were no significant interfering ion effects on the electroanalysis of metsulfuron-methyl. The optimized parameters were then used to determine metsulfuron-methyl in the commercial pesticide Ally. The proposed method was highly sensitive due to the lower limit of determination (0.04 mg/L), being relatively selective, and consisting of good precision. The recovery values achieved were about 93% in water samples for this analysis.
  11. Chaudhry IS, Yusop Z, Habibullah MS
    Environ Sci Pollut Res Int, 2022 Jan;29(4):5360-5377.
    PMID: 34417974 DOI: 10.1007/s11356-021-15941-9
    The disastrous consequences of climate change for human life and environmental sustainability have drawn worldwide attention. Increased global warming is attributed to anthropogenic greenhouse gas (GHG) emissions, biodiversity loss, and deforestation due to industrial output and huge consumption of fossil fuels. Financial inclusion can be acted as an adaptation or a mitigation measure for environmental degradation. This study analyzed the impact of financial inclusion on environmental degradation in OIC countries for the period 2004-2018. A novel approach, "Dynamic Common Correlated Effects (DCCE)" is used to tackle the problem of heterogeneity and cross-sectional dependence (CSD). Various GHG emissions along with deforestation and ecological footprint are used as indicators of environmental degradation. Long-run estimation confirms that financial inclusion is positively and significantly linked with CO2 emission, CH4 emission, and deforestation while negatively correlated with ecological footprint and N2O emission in overall and higher-income OIC economies. An inverted U-shaped environmental Kuznets curve (EKC) is validated when ecological footprint, CO2, and CH4 are used in all panels of OIC countries. An inverted U-shaped EKC is also observed for deforestation in lower-income and overall OIC countries. In the case of N2O emission, however, a U-shaped EKC appears in lower-income and overall OIC countries. It is suggested that the governments of OIC countries should continue to have easy access to financial services and maintain sustainable use of forests and biocapacity management to address environmental challenges.
  12. Ali S, Yusop Z, Meo MS
    PMID: 34854006 DOI: 10.1007/s11356-021-17473-8
    Trade openness continues to have the potential to influence many parts of today's society, including religion, transportation, lifestyle, language, and international relations; however, its ability to impact environmental quality is the primary issue for environmental policy guidelines. In response to an increasing interest in finding the dynamic association between trade openness and environmental quality, the current study explores the trade openness- environmental quality nexus in the ten most open Organization of Islamic Cooperation (OIC) countries for the years 1991 to 2018. By taking CO2 emissions and ecological footprint as environmental indicators, a novel methodology "quantile-on-quantile (QQ)" is used to indicate how different quantiles of trade openness asymmetrically affect the quantiles of environmental indicators by providing an adequate pattern to comprehend the overall dependence structure. A negative openness-CO2 emissions association is dominant in seven out of ten selected OIC countries (i.e., Suriname, Malaysia, Jordan, UAE, Libya, Brunei, and Qatar). On the other hand, a positive impact of trade openness on ecological footprint is dominant in eight out of ten selected OIC countries (i.e., Oman, Jordan, UAE, Libya, Bahrain, Brunei, Qatar, and Kuwait). The outcomes indicate that the asymmetric strength of openness-induced environmental quality differs with countries at both upper and bottom quantiles of data distribution that need specific attention in contending trade and environment policies in OIC countries.
  13. Adham MI, Shirazi SM, Othman F, Rahman S, Yusop Z, Ismail Z
    ScientificWorldJournal, 2014;2014:379763.
    PMID: 25152911 DOI: 10.1155/2014/379763
    Runoff potentiality of a watershed was assessed based on identifying curve number (CN), soil conservation service (SCS), and functional data analysis (FDA) techniques. Daily discrete rainfall data were collected from weather stations in the study area and analyzed through lowess method for smoothing curve. As runoff data represents a periodic pattern in each watershed, Fourier series was introduced to fit the smooth curve of eight watersheds. Seven terms of Fourier series were introduced for the watersheds 5 and 8, while 8 terms of Fourier series were used for the rest of the watersheds for the best fit of data. Bootstrapping smooth curve analysis reveals that watersheds 1, 2, 3, 6, 7, and 8 are with monthly mean runoffs of 29, 24, 22, 23, 26, and 27 mm, respectively, and these watersheds would likely contribute to surface runoff in the study area. The purpose of this study was to transform runoff data into a smooth curve for representing the surface runoff pattern and mean runoff of each watershed through statistical method. This study provides information of runoff potentiality of each watershed and also provides input data for hydrological modeling.
  14. Yusop Z, Tan LW, Ujang Z, Mohamed M, Nasir KA
    Water Sci Technol, 2005;52(9):125-32.
    PMID: 16445181
    Runoff quality draining from 17.14 km2 urban catchment in Johor Bahru, Malaysia, was analysed. The land-use consists of residential (30.3%), agricultural (27.3%), open space (27.9%), industrial (8.1%) and commercial (6.4%) areas. Three storm events were sampled in detail. These storms produced stormflow between 0.84 mm and 27.82 mm, and peakflow from 2.19 m3/s to 42.36 m3/s. Water quality showed marked variation during storms especially for TSS, BOD and COD with maximum concentrations of 778 mg/l, 135 mg/l and 358 mg/l, respectively. Concentrations of TOC, DOC, NH3-N, Fe and level of colour were also high. In general, the river quality is badly polluted and falls in Class V based on the Malaysian Interim National Water Quality Standards. Event Mean Concentrations (EMC) for various parameters varied considerably between storms. The largest storm produced higher EMC for TSS, NO3-N and SS whereas the smaller storms tend to register higher EMC for BOD, COD, NH3-N, TOC, Ca, K, Mg, Fe and Zn. Such variations could be explained in terms of pollutant availability and the effects of flushing and dilution. Based on a three-month average recurrence interval (ARI) of rainfall, the estimated event loadings (ton/ha) of TSS, BOD, COD, TOC, NH3-N and NO3-N were 0.055, 0.016, 0.012, 0.039, 0.010, 0.0007 and 0.0002, respectively. Heavy metals present in trace quantities. Storms with 3 months ARI could capture about 70% of the total annual loads of major pollutants.
  15. Benalywa ZA, Ismail MM, Shamsudin MN, Yusop Z
    Trop Anim Health Prod, 2019 Feb;51(2):321-327.
    PMID: 30112733 DOI: 10.1007/s11250-018-1690-8
    Broiler meat is the largest and cheapest protein source in Malaysia. Using the policy analysis matrix (PAM), this study examines the comparative advantage of broiler production in Peninsular Malaysia. Three hundred and ten farms in Peninsular Malaysia were involved in a field survey. The results of the domestic resource cost (DRC) show that Malaysia has a comparative advantage in all scales of broiler production. Sensitivity analysis indicates that the changes in input prices have a significant effect on comparative advantage. Nonetheless, the industry should reduce its dependence on corn-based feed, which is expensive and has an unstable price, to increase competitiveness in further securing its comparative advantage.
  16. Vijaya Bhaskar Reddy A, Yusop Z, Jaafar J, Madhavi V, Madhavi G
    Curr Drug Discov Technol, 2016;13(4):211-224.
    PMID: 27697028
    Drug discovery is a highly complicated, tedious and potentially rewarding approach associated with great risk. Pharmaceutical companies literally spend millions of dollars to produce a single successful drug. The drug discovery process also need strict compliance to the directions on manufacturing and testing of new drug standards before their release into market. All these regulations created the necessity to develop advanced approaches in drug discovery. The contributions of advanced technologies including high resolution analytical instruments, 3-D biological printing, next-generation sequencing and bioinformatics have made positive impact on drug discovery & development. Fortunately, all these advanced technologies are evolving at the right time when new issues are rising in drug development process. In the present review, we have discussed the role of genomics and advanced analytical techniques in drug discovery. Further, we have also discussed the significant advances in drug discovery as case studies.
  17. Ali S, Yusop Z, Kaliappan SR, Chin L
    Environ Sci Pollut Res Int, 2021 Jan;28(4):4531-4548.
    PMID: 32944853 DOI: 10.1007/s11356-020-10845-6
    Being closely correlated with income and economic growth, trade openness impacts the environmental quality through different means. The study analyzes the robustness of the environmental Kuznets curve (EKC) hypothesis in OIC countries by examining the extent to which trade openness influence environmental quality through different environmental indicators for the period 1991 to 2018. A new methodology dynamic common correlated effects (DCCE) is applied to resolve the issue of cross-sectional dependence (CSD). We have used greenhouse gas (GHG) emissions, carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) along with ecological footprint as indicators of environmental quality. Results of DCCE estimation identify a negative association of trade openness with CO2, N2O, and CH4, while the positive relationship with the ecological footprint in overall OIC countries and higher income OIC countries. On the other hand, trade openness has a positive association with all environmental indicators in lower income OIC countries. Our findings confirm that inverted-U-shaped EKC exists in all groups of OIC countries when CO2, CH4, and ecological footprint are used as environmental indicators. However, a U-shaped EKC exists in overall OIC countries and lower income OIC countries when N2O is used. Eventually, it is recommended that if OIC countries continue trade openness policies and energy sector reforms and maintain sustainable use of biocapacity; then, they will be able to combat environmental issues with the increase in income.
  18. Muhamad MS, Salim MR, Lau WJ, Yusop Z
    Environ Sci Pollut Res Int, 2016 Jun;23(12):11549-67.
    PMID: 26939684 DOI: 10.1007/s11356-016-6357-2
    Massive utilization of bisphenol A (BPA) in the industrial production of polycarbonate plastics has led to the occurrence of this compound (at μg/L to ng/L level) in the water treatment plant. Nowadays, the presence of BPA in drinking water sources is a major concern among society because BPA is one of the endocrine disruption compounds (EDCs) that can cause hazard to human health even at extremely low concentration level. Parallel to these issues, membrane technology has emerged as the most feasible treatment process to eliminate this recalcitrant contaminant via physical separation mechanism. This paper reviews the occurrences and effects of BPA toward living organisms as well as the application of membrane technology for their removal in water treatment plant. The potential applications of using polymeric membranes for BPA removal are also discussed. Literature revealed that modifying membrane surface using blending approach is the simple yet effective method to improve membrane properties with respect to BPA removal without compromising water permeability. The regeneration process helps in maintaining the performances of membrane at desired level. The application of large-scale membrane process in treatment plant shows the feasibility of the technology for removing BPA and possible future prospect in water treatment process.
  19. Farooq F, Yusop Z, Chaudhry IS, Iram R
    Environ Sci Pollut Res Int, 2020 Mar;27(7):6904-6917.
    PMID: 31879877 DOI: 10.1007/s11356-019-07289-y
    The contemporary debate on globalization and gender equality has a strong impact on economic growth. The present study analyzes the impacts of globalization and gender parity on economic growth in the Organization of Islamic Cooperation (OIC) 47 member countries for the period (1991-2017), using System GMM panel data technique. The results of system GMM have also been empirically estimated by making two groups (viz., low-income and high-income OIC member countries from the World Bank data classification, 2019) to examine the robustness of globalization and gender parity on economic growth. The results reveal that there is a negative impact of globalization on economic growth in the overall sample of OIC countries. When estimated by decomposing low-income countries and high-income countries, globalization has a significantly positive impact on economic growth in the case of high-income OIC countries, whereas globalization slashes GDP in the case of low-income OIC countries. The study finds that there is a positive impact of gender parity (ratio of female to male labor force work participation) on economic growth. Moreover, foreign remittances, government expenditures, capital formation, and human capital are also becoming the causes of a significant increase in economic growth in OIC member countries.
  20. Ali S, Yusop Z, Kaliappan SR, Chin L
    Environ Sci Pollut Res Int, 2020 Apr;27(11):11671-11682.
    PMID: 31970640 DOI: 10.1007/s11356-020-07768-7
    The study aims to address the dynamic common correlated effects of trade openness, FDI, and institutional performance on environmental quality in OIC countries. Mostly, pollutants like CO2 and SO2 emissions are considered as the environmental indicators. However, for this study, we have selected ecological footprint as the indicator of environmental quality. The new econometric approach Dynamic Common Correlated Effects (DCCE) by Chudik and Pesaran (2015) has been used to measure the cross-sectional dependence among cross-sectional units. Results confirm that previous techniques for long panel data, like MG and PMG, give ambiguous outcomes in the presence of cross-sectional dependence. According to DCCE estimation, trade openness, FDI, and urbanization have a positive and significant relationship with ecological footprint while a significant and negative association is found between institutional performance and ecological footprint. The OIC countries must encourage green technology, clean production, and improved institutions for sustainable development and better environmental quality.
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