Allium cepa assay was carried out in this study to evaluate genotoxic effects of raw and treated water samples from Perak River in Perak state, Malaysia. Samples were collected from three surface water treatment plants along the river, namely WTPP, WTPS, and WTPK. Initially, triplicates of equal size Allium cepa (onions) bulbs, 25-30 mm in diameter and average weight of 20 g, were set up in distilled water for 24 h at 20 ± 2 °C and protected from direct sunlight, to let the roots to grow. After germination of roots (0.5-1.0 cm in length), bulbs were transferred to collected water samples each for a 96-h period of exposure. The root physical deformations were observed. Genotoxicity quantification was based on mitotic index and genotoxicity level. Statistical analysis using cross-correlation function for replicates from treated water showed that root length has inverse correlation with mitotic indices (r = - 0.969) and frequencies of cell aberrations (r = - 0.976) at lag 1. Mitotic indices and cell aberrations of replicates from raw water have shown positive correlation at lag 1 (r = 0.946). Genotoxicity levels obtained were 23.4 ± 1.98 (WTPP), 26.68 ± 0.34 (WTPS), and 30.4 ± 1.13 (WTPK) for treated water and 17.8 ± 0.18 (WTPP), 37.15 ± 0.17 (WTPS), and 47.2 ± 0.48 (WTPK) for raw water. The observed cell aberrations were adherence, chromosome delay, C-metaphase, chromosome loss, chromosome bridge, chromosome breaks, binucleated cell, mini cell, and lobulated nuclei. The morphogenetic deformations obtained were likely due to genotoxic substances presence in collected water samples. Thus, water treatment in Malaysia does not remove genotoxic compounds.
Seasonal haze episodes and the associated inimical health impacts have become a regular crisis among the ASEAN countries. Even though many emerging experimental and epidemiological studies have documented the plausible health effects of the predominating toxic pollutants of haze, the consistency among the reported findings by these studies is poorly understood. By addressing such gap, this review aimed to critically highlight the evidence of physical and psychological health impacts of haze from the available literature in ASEAN countries. Systematic literature survey from six electronic databases across the environmental and medical disciplines was performed, and 20 peer-reviewed studies out of 384 retrieved articles were selected. The evidence pertaining to the health impacts of haze based on field survey, laboratory tests, modelling and time-series analysis were extracted for expert judgement. In specific, no generalization can be made on the reported physical symptoms as no specific symptoms recorded in all the reviewed studies except for throat discomfort. Consistent evidence was found for the increase in respiratory morbidity, especially for asthma, whilst the children and the elderly are deemed to be the vulnerable groups of the haze-induced respiratory ailments. A consensual conclusion on the association between the cardiovascular morbidity and haze is unfeasible as the available studies are scanty and geographically limited albeit of some reported increased cases. A number of modelling and simulation studies demonstrated elevating respiratory mortality rates due to seasonal haze exposures over the years. Besides, evidence on cancer risk is inconsistent where industrial and vehicular emissions are also expected to play more notable roles than mere haze exposure. There are insufficient regional studies to examine the association between the mental health and haze. Limited toxicological studies in ASEAN countries often impede a comprehensive understanding of the biological mechanism of haze-induced toxic pollutants on human physiology. Therefore, the lack of consistent evidence among the reported haze-induced health effects as highlighted in this review calls for more intensive longitudinal and toxicological studies with greater statistical power to disseminate more reliable and congruent findings to empower the institutional health planning among the ASEAN countries.
This study investigated the reaction kinetics and mechanism of the degradation of 5,5-diphenylhydantoin (DPH) during conventional chlorination and UV/chlorination. DPH is one of the antiepileptic drugs, which has frequently been detected in the aquatic environment. For chlorination, the second-order rate constant for the reaction between DPH and free active chlorine (FAC) was determined at pH 5 to 8. At pH 6 to 8, the efficiency of chlorination in the removal of DPH was found to be dominated by the reaction involving hypochlorous acid (HOCl). The result also showed that anionic species of DPH was more reactive toward FAC as compared with neutral DPH. For UV/chlorination, the effect of FAC dosage and pH on the degradation of DPH was evaluated. UV/chlorination is a more effective method for removing DPH as compared with conventional chlorination and UV irradiation. The DPH degradation rate was found to increase with increasing FAC concentration. On the other hand, the degradation of DPH was found to be more favorable under the acidic condition. Based on the identified transformation by-products, DPH was found to be degraded through the reaction at imidazolidine-2,4-dione moiety of DPH for both chlorination and UV/chlorination. Toxicity study on the chlorination and UV/chlorination-treated DPH solutions suggested that UV/chlorination is a more efficient method for reducing the toxicity of DPH.
The release of pollutants, especially heavy metals, into the aquatic environment is known to have detrimental effects on such an environment and on living organisms including humans when those pollutants are allowed to enter the food chain. The aim of this study is to analyse the damage to Clarias gariepinus' liver caused by exposure to different concentrations of copper. In the present study, samples of C. gariepinus were exposed to sub-lethal copper sulphate (CuSO4) concentrations (from 0.2 to 20.0 mg/L) for 96 h. Physiological and behavioural alterations were observed with respect to their swimming pattern, mucus secretion and skin colour. Mortality was also observed at high concentrations of copper. Histopathological alterations of the liver were analysed under light, transmission and scanning electron microscopies. The liver of the untreated group showed normal tissue structures, while histopathological abnormalities were observed in the treated fish under light and electron microscopes with increased copper concentrations. Histopathological abnormalities include necrosis, melanomacrophage, hepatic fibrosis and congested blood vessels. In addition, the enzyme activity of liver cholinesterase (ChE) was also found to be affected by copper sulphate, as 100% of cholinesterase activity was inhibited at 20.0 mg/L. Thus, liver enzyme activity and histopathological changes are proven to be alternative sources for biomarkers of metal toxicity.
This study investigates whether financial development dampens the negative impact of oil resource abundance on economic growth. Because of substantial cross-sectional dependence in our data, which contain a core sample of 63 oil-producing countries from 1980 through 2010, we use the common correlated effect mean group (CCEMG) estimator to account for the high degree of heterogeneity and drop the outlier countries. The empirical results reveal that oil resource abundance affects the growth rate in output contingent on the degree of development in financial markets. More developed financial markets can channel the revenues from oil into more productive activities and thus offset the negative effects of oil resource abundance on economic growth. Thus, better financial development can reverse resource curse or enhance resource blessing in oil-rich economies.
The main objective of this study is to investigate the influence of the globalisation (Trans-Pacific Partnership (TPP) agreement in particular) on air pollution in Malaysia. To achieve this goal, the Autoregressive Distributed Lag (ARDL) model, Johansen cointegration test and fully modified ordinary least square (FMOLS) methods are utilised. CO2 emission is used as an indicator of pollution while GDP per capita and urbanisation serve as its other determinants. In addition, this study uses Malaysia's total trade with 10 TPP members as an indicator of globalisation and analyse its effect on CO2 emission in Malaysia. The outcome of this research shows that the variables are cointegrated. Additionally, GDP per capita, urbanisation and trade between Malaysia and its 10 TPP partners have a positive impact on CO2 emissions in general. Based on the outcome of this research, important policy implications are provided for the investigated country.
A novel sustainable hybrid system of photocatalytic fuel cell (PFC) and Fenton process is an alternative wastewater treatment technology for energy-saving and efficient treatment of organic pollutants. The electrons generated from PFC photoanode are used to produce H2O2 in the Fenton reactor and react with the in situ generation of Fe2+ from sacrificial iron for hydroxyl radical formation. In this study, the effect of different initial Amaranth dye concentrations on degradation and electricity generation were investigated. ZnO/Zn photoanode was prepared by anodizing method and characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results revealed that the maximum power density (9.53 mW/m2) and current density (0.0178 mA/m2) were achieved at 10 mg/L of Amaranth. The correlation between dye degradation, voltage output, and kinetic photocatalytic degradation were also investigated and discussed.
The present paper aims to assess the phytoremediation performance based on pollution removal efficiency of the highly polluted region of Alur Ilmu urban river for its applicability of on-site treatment. Thirteen stations along Alur Ilmu were selected to produce thematic maps through spatial distribution analysis based on six water quality parameters of Malaysia's Water Quality Index (WQI) for dry and raining seasons. The maps generated were used to identify the highly polluted region for phytoremediation applicability assessment. Four free-floating plants were tested in treating water samples from the highly polluted region under three different conditions, namely controlled, aerated and normal treatments. The selected free-floating plants were water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), rose water lettuce (Pistia sp.) and pennywort (Centella asiatica). The results showed that Alur Ilmu was more polluted during dry season compared to raining season based on the water quality analysis. During dry season, four parameters were marked as polluted along Alur Ilmu, namely dissolve oxygen (DO), 4.72 mg/L (class III); ammoniacal nitrogen (NH3-N), 0.85 mg/L (class IV); total suspended solid (TSS), 402 mg/L (class V) and biological oxygen demand (BOD), 3.89 mg/L (class III), whereas, two parameters were classed as polluted during raining season, namely total suspended solid (TSS), 571 mg/L (class V) and biological oxygen demand (BOD), 4.01 mg/L (class III). The thematic maps generated from spatial distribution analysis using Kriging gridding method showed that the highly polluted region was recorded at station AL 5. Hence, water samples were taken from this station for pollution removal analysis. All the free-floating plants were able to reduce TSS and COD in less than 14 days. However, water hyacinth showed the least detrimental effect from the phytoremediation process compared to other free-floating plants, thus made it a suitable free-floating plants to be used for on-site treatment.
The development of novel mosquito control tools is a key prerequisite to build effective and reliable Integrated Vector Management strategies. Here, we proposed a novel method using cigarette butts for the synthesis of Ag nanostructures toxic to young instars of the malaria vector Anopheles stephensi, chloroquine (CQ)-resistant malaria parasites Plasmodium falciparum and microbial pathogens. The non-target impact of these nanomaterials in the aquatic environment was evaluated testing them at sub-lethal doses on the predatory copepod Mesocyclops aspericornis. Cigarette butt-synthesized Ag nanostructures were characterized by UV-vis and FTIR spectroscopy, as well as by EDX, SEM and XRD analyses. Low doses of cigarette butt extracts (with and without tobacco) showed larvicidal and pupicidal toxicity on An. stephensi. The LC50 of cigarette butt-synthesized Ag nanostructures ranged from 4.505 ppm (I instar larvae) to 8.070 ppm (pupae) using smoked cigarette butts with tobacco, and from 3.571 (I instar larvae) to 6.143 ppm (pupae) using unsmoked cigarette butts without tobacco. Smoke toxicity experiments conducted against adults showed that unsmoked cigarette butts-based coils led to mortality comparable to permethrin-based positive control (84.2 and 91.2%, respectively). A single treatment with cigarette butts extracts and Ag nanostructures significantly reduced egg hatchability of An. stephensi. Furthermore, the antiplasmodial activity of cigarette butt extracts (with and without tobacco) and synthesized Ag nanostructures was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of P. falciparum. The lowest IC50 values were achieved by cigarette butt extracts without tobacco, they were 54.63 μg/ml (CQ-s) and 63.26 μg/ml (CQ-r); while Ag nanostructure IC50 values were 72.13 μg/ml (CQ-s) and 77.33 μg/ml (CQ-r). In MIC assays, low doses of the Ag nanostructures inhibited the growth of Bacillus subtilis, Klebsiella pneumoniae and Salmonella typhi. Finally, the predation efficiency of copepod M. aspericornis towards larvae of An. stephensi did not decrease in a nanoparticle-contaminated environment, if compared to control predation assays. Overall, the present research would suggest that an abundant hazardous waste, such as cigarette butts, can be turned to an important resource for nanosynthesis of highly effective antiplasmodials and insecticides.
In light of a slow buildup in CO2 emissions since the recovery, this paper revisits the relationship between CO2 emissions and the US economy using a nonlinear autoregressive distributed lag model, in which the determinants are identified through an expanded real business cycle model. We find convincing evidence that CO2 emissions decline more rapidly during recessions than increase during expansions over the long run. Of all determinants considered, long-run asymmetry is fostered once vehicle miles traveled is controlled. This calls for a greater attention to public transportation development and vehicle miles traveled tax for slowing down stock buildup of CO2 emissions during good times.
In this study, the chemical substance flow of hydrogen fluoride (hydrofluoric acid, HF) in domestic chemical industries in 2014 was analyzed in order to provide a basic material and information for the establishment of organized management system to ensure safety during HF applications. A total of 44,751 tons of HF was made by four domestic companies (in 2014); import amount was 95,984 tons in 2014 while 21,579 tons of HF was imported in 2005. The export amount of HF was 2180 tons, of which 2074 ton (China, 1422 tons, U.S. 524 tons, and Malaysia, 128 tons) was exported for the manufacturing of semiconductors. Based on the export and import amounts, it can be inferred that HF was used for manufacturing semiconductors. The industries applications of 161,123 tons of HF were as follows: manufacturing of basic inorganic chemical substance (27,937 tons), manufacturing of other chemical products such as detergents (28,208 tons), manufacturing of flat display (24,896 tons), and manufacturing of glass container package (22,002 tons). In this study, an analysis of the chemical substance flow showed that HF was mainly used in the semiconductor industry as well as glass container manufacturing. Combined with other risk management tools and approaches in the chemical industry, the chemical substance flow analysis (CSFA) can be a useful tool and method for assessment and management. The current CSFA results provide useful information for policy making in the chemical industry and national systems. Graphical abstract Hydrogen fluoride chemical substance flows in 2014 in South Korea.
This study examines the three-way linkage relationships between CO2 emission, energy consumption and economic growth in Malaysia, covering the 1975-2015 period. An autoregressive distributed lag approach was employed to achieve the objective of the study and gauged by dynamic ordinary least squares. Additionally, vector error correction model, variance decompositions and impulse response functions were employed to further examine the relationship between the interest variables. The findings show that economic growth is neither influenced by energy consumption nor by CO2 emission. Energy consumption is revealed to be an increasing function of CO2 emission. Whereas, CO2 emission positively and significantly depends on energy consumption and economic growth. This implies that CO2 emission increases with an increase in both energy consumption and economic growth. Conclusively, the main drivers of CO2 emission in Malaysia are proven to be energy consumption and economic growth. Therefore, renewable energy sources ought to be considered by policy makers to curb emission from the current non-renewable sources. Wind and biomass can be explored as they are viable sources. Energy efficiency and savings should equally be emphasised and encouraged by policy makers. Lastly, growth-related policies that target emission reduction are also recommended.
The composition of heavy metals (and metalloid) in surface soils of iron ore mine-impacted areas has been evaluated of their potential ecological and human health risks. The mining areas included seven selected locations in the vicinity of active and abandoned iron ore-mining sites in Pahang, Malaysia. Heavy metals such as Fe, Mn, Cu, Zn, Co, Pb, Cr, Ni, and Cd and metalloid As were present in the mining soils of the studied area, while Cu was found exceeding the soil guideline value at all sampling locations. However, the assessment of the potential ecological risk index (RI) indicated low ecological risk (RI between 44 and 128) with respect to Cd, Pb, Cu, As, Zn, Co, and Ni in the surface soils. Contributions of potential ecological risk [Formula: see text]by metal elements to the total potential ecological RI were evident for Cd, As, Pb, and Cu. Contribution of Cu appears to be consistently greater in the abandoned mining area compared to active iron ore-mining site. For non-carcinogenic risk, no significant potential health risk was found to both children and adults as the hazard indices (HIs) were all below than 1. The lifetime cancer risk (LCR) indicated that As has greater potential carcinogenic risk compared to other metals that may induce carcinogenic effects such as Pb, Cr, and Cd, while the LCR of As for children fell within tolerable range for regulatory purposes. Irrespective of carcinogenic or non-carcinogenic risk, greater potential health risk was found among children (by an order of magnitude higher for most metals) compared to adults. The hazard quotient (HQ) and cancer risk indicated that the pathways for the risk to occur were found to be in the order of ingestion > dermal > inhalation. Overall, findings showed that some metals and metalloid were still present at comparable concentrations even long after cessation of the iron ore-mining activities.
The relationship between environmental factors and human health has long been a concern among academic researchers. We use two indicators of environmental pollution, namely particulate matter (PM10) and carbon dioxide (CO2) to examine the effects of poor air quality on human mortality. This study explores an issue that has largely been ignored, particularly in the African literature, where the effect of air pollution on human mortality could be influenced by gender specification. We analyse a panel data from 35 African countries and our result suggests that the elevated levels of PM10 and CO2 have a significant effect on the increasing mortality rates in infants, under-five children and adults. Although the effect of poor air quality on adults is found to differ between genders, such difference is not statistically significant. We conclude that the air pollution effects, on average, are similar between genders in the African countries.
The Klang area of Peninsular Malaysia has experienced rapid industrial growth with intense activities, which can increase the concentration of pollutants in the environment that significantly impact on habitats and the human health. The purpose of this study was to determine the levels of selected heavy metals (Cu, Zn, Ni, Fe, and Pb) in the heart, lung, brain, liver, kidney, muscle tissues, and feathers of house crow, Corvus splendens, in Klang, Peninsular Malaysia. House crow samples were collected from the Klang area through the Department of Public Health at Majlis Perbandaran Klang. Quantitative determination of heavy metals was carried out using atomic absorption spectrophotometer (AAS). The result shows the presence of heavy metals in all biological samples of house crows. For heavy metals in all the house crow tissues analyzed, Fe concentrations were the highest, followed by those of Zn, Cu, Pb, and Ni. The feathers and kidney accumulated high concentrations of Pb, whereas the liver accumulated high concentrations of essential heavy metals (Fe > Zn > Cu > Ni). Significant variations were also detected in the concentrations of Pb among adult and juvenile and male and female bird samples. The results also revealed significant positive correlations between Pb metal concentration in the breast feathers and all internal organs. Accumulation of toxic heavy metals in feathers reflected storing and elimination processes, while the accumulation of toxic heavy metals in the kidney can be consequential to chronic exposure. The present study clearly shows the usefulness of house crow breast feather as a suitable indicator for heavy metal accumulation in the internal organs of house crows in the Klang area.
Treatment of oil-contaminated soil is a major environmental concern worldwide. The aim of this study is to examine the applicability of a green solvent, ethyl lactate (EL), in desorption of diesel aliphatic fraction within total petroleum hydrocarbons (TPH) in contaminated soil and to determine the associated desorption kinetics. Batch desorption experiments were carried out on artificially contaminated soil at different EL solvent percentages (%). In analysing the diesel range of TPH, TPH was divided into three fractions and the effect of solvent extraction on each fraction was examined. The experimental results demonstrated that EL has a high and fast desorbing power. Pseudo-second order rate equation described the experimental desorption kinetics data well with correlation coefficient values, R (2), between 0.9219 and 0.9999. The effects of EL percentage, initial contamination level of soil and liquid to solid ratio (L/S (v/w)) on initial desorption rate have also been evaluated. The effective desorption performance of ethyl lactate shows its potential as a removal agent for remediation of TPH-contaminated soil worldwide.
The wide application of microalgae in the field of wastewater treatment and bioenergy source has improved research studies in the past years. Microalgae represent a good source of biomass and bio-products which are used in different medical and industrial activities, among them the production of high-valued products and biofuels. The present review focused on greywater treatment through the application of phycoremediation technique with microalgae and presented recent advances in technologies used for harvesting the microalgae biomass. The advantages and disadvantages of each method are discussed. The microbiological aspects of production, harvesting and utilization of microalgae biomass are viewed.
This study has applied the concept of the hybrid PAC-UF process in the treatment of the final effluent of the palm oil industry for reuse as feedwater for low-pressure boilers. In a bench-scale set-up, a low-cost empty fruit bunch-based powdered activated carbon (PAC) was employed for upstream adsorption of biotreated palm oil mill effluent (BPOME) with the process conditions: 60 g/L dose of PAC, 68 min of mixing time and 200 rpm of mixing speed, to reduce the feedwater strength, alleviate probable fouling of the membranes and thus improve the process flux (productivity). Three polyethersulfone ultrafiltration membranes of molecular weight cut-off (MWCO) of 1, 5 and 10 kDa were investigated in a cross-flow filtration mode, and under constant transmembrane pressures of 40, 80, and 120 kPa. The permeate qualities of the hybrid processes were evaluated, and it was found that the integrated process with the 1 kDa MWCO UF membrane yielded the best water quality that falls within the US EPA reuse standard for boiler-feed and cooling water. It was also observed that the permeate quality is fit for extended reuse as process water in the cement, petroleum and coal industries. In addition, the hybrid system's operation consumed 37.13 Wh m(-3) of energy at the highest applied pressure of 120 kPa, which is far lesser than the typical energy requirement range (0.8-1.0 kWh m(-3)) for such wastewater reclamation.
For the synthesis of a highly active TiO2-chitosan nanocomposite, pH plays a crucial role towards controlling its morphology, size, crystallinity, thermal stability, and surface adsorption properties. The presence of chitosan (CS) biopolymer facilitates greater sustainability to the photoexcited electrons and holes on the catalysts' surface. The variation of synthesis pH from 2 to 5 resulted in different physico-chemical and photocatalytic properties, whereby a pH of 3 resulted in TiO2-chitosan nanocomposite with the highest photocatalytic degradation (above 99 %) of methylene orange (MO) dye. This was attributed to the efficient surface absorption properties, high crystallinity, and the presence of reactive surfaces of -NH2 and -OH groups, which enhances the adsorption-photodegradation effect. The larger surface oxygen vacancies coupled with reduced electron-hole recombination further enhanced the photocatalytic activity. It is undeniable that the pH during synthesis is critical towards the development of the properties of the TiO2-chitosan nanocomposite for the enhancement of photocatalytic activity.
We identified marine fish species most preferred by women at reproductive age in Selangor, Malaysia, mercury concentrations in the fish muscles, factors predicting mercury accumulation and the potential health risk. Nineteen most preferred marine fish species were purchased (n = 175) from selected fisherman's and wholesale market. Length, weight, habitat, feeding habit and trophic level were recognised. Edible muscles were filleted, dried at 80 °C, ground on an agate mortar and digested in Multiwave 3000 using HNO3 and H2O2. Total mercury was quantified using VP90 cold vapour system with N2 carrier gas. Certified reference material DORM-4 was used to validate the results. Fish species were classified as demersal (7) and pelagic (12) or predators (11), zoo benthos (6) and planktivorous (2). Length, weight and trophic level ranged from 10.5 to 75.0 cm, 0.01 to 2.50 kg and 2.5 to 4.5, respectively. Geometric mean of total mercury ranged from 0.21 to 0.50 mg/kg; maximum in golden snapper (0.90 mg/kg). Only 9 % of the samples exceeded the JECFA recommendation. Multiple linear regression found demersal, high trophic (≥4.0) and heavier fishes to accumulate more mercury in muscles (R (2) = 27.3 %), controlling for all other factors. About 47 % of the fish samples contributed to mercury intake above the provisional tolerable level (45 μg/day). While only a small portion exceeded the JECFA fish Hg guideline, the concentration reported may be alarming for heavy consumers. Attention should be given in risk management to avoid demersal and high trophic fish, predominantly heavier ones.