Solar photocatalysis is a green technology that takes advantage of sustainable solar energy for enhancing oxidation process of numerous harmful water contaminants. In this study, a custom solar driven zinc oxide (ZnO)-mediated photocatalytic system was developed and its efficiency to remove organic contaminants as well as to disinfect selected bacteria was investigated. Methylene blue (MB) dye was used as the model organic contaminant, while Escherichia coli(E.coli) was used as the model fecal coliform bacteria in contaminated water. A series of photodegradation experiments were conducted on water contaminated with either 10 mg/L of MB or ~1010CFU/ml of E.coli. The experiments were completed under sunlight irradiation in the presence of 1 g/L of nano ZnO photocatalyst for up to 6 hours. Using a solar thermal collector, the photoreactor operated in the temperature range of 25 to 50 oC. The findings revealed that the combination of solar thermal with solar photocatalysis usingZnO intensified the degradation of MB and disinfection of E.coli. 98.08% of MB dye and 99.99% of E.coliwere successfully removed from the water within the first 3 hours of treatment. Almost complete removal was eventually achieved after 6 hours of treatment. It is therefore suggested that ZnO-based solar photocatalytic system developed in this study is highly efficient at enhancing water decontamination process.
Recently, the graphite based materials have gained interest as excellent platforms to remove aqueous pollutants via adsorption routes. This is given that such materials possess large specific surface area and low density. In the present work, a comparative study of two facile and effective approaches is conventional thermal heating and microwave irradiation methods to fabricate expanded graphite from available flake graphite sources of Vietnam for oil-contaminated water purification. The as-prepared expanded graphite was characterized by using FT-IR, SEM, XRD and BET analysis. The results exhibited that expanded graphite has multilevel pore structures and the surface area of expanded graphite obtained from microwave irradiation and conventional heating was 147.5 (m²/g) and 100.97 (m²/g) under optimal processing conditions. The as-synthesized expanded graphite from the microwave irradiation method was found to have higher adsorption capacities for diesel oil, crude oil, and fuel oil compared to conventional heating method.
Acute Gastroenteritis (AGE) is common world wide and is a major health problem. The commonest cause is from contaminated water or food. Common infective agents are Rotavirus, Staph. aureus and Bacillus cereus. There was an AGE outbreak in Ipoh City from late August till early October 2006. Epidemiological and laboratory investigations were done. Fresh stool samples were taken from symptomatic patients. Water and food sampling were also done. Descriptive analysis of the outbreak was done. A total of 170 patients, mostly between 1 - 5 years of age, were affected. The highest incidents were seen in Bercham. Fever and diarrhea were the prominent features. Two stool samples (13.3%) were positive for E.coli and rotavirus respectively. Twelve of the twenty (60%) water samples taken were contaminated with coliform and fecal matter. Twenty-one of the eighty ((26.3%) food samples taken grew either E.coli, Staph. aureus or Bacillus cereus. It was concluded that a general source was responsible for this problem. The water supply to Ipoh City and the surrounding area is the most likely source. Novovirus was suspected as the organism involved because of the self-limiting and mild nature of the illness that occurred in this outbreak.
The AGE outbreak in Kinta District in September 2006 is due to contaminated
water supply from two water treatment
Gelatin from fish skin is known to be an alternative source for mammalian gelatin. However, it has weaker properties compared to bovine and porcine gelatin, which limits its use in the industry. The conventional method for fish gelatin extraction requires long production time and could cause serious water pollution and chemical treatments are often being used to enhance the yield of fish gelatin and its properties but it may affect the amino acid content of the gelatin. In this regard, High-Pressure Processing (HPP) is a novel method suggested for fish gelatin extraction. The HPP method is classified as green technology as it requires low electricity throughout the process. This study will discuss the impact of HPP the technique gelatin extracted from fish skin. Skins from four types of fish, namely red tilapia (Oreochromis niloticus), black tilapia (Oreochromis mossambicus), grouper (Epinephelus areolatus) and threadfin bream (Nemipterus tambuloides), were used. High pressure was applied at either pretreatment in citric acid solution or during thermal extraction; and the pressure was maintained at 250 MPa with pressure holding time of 10 minutes and 18 hours of water extraction. Gelatin extract from traditional acid-base method was prepared as a standard for comparison. The study found that there was an increment in the yield of gelatin and the concentration of gelatin extract, and the pre-treatment time was also reduced.
Clean water is very important for health and well-being of humans and ecosystem. However, over the year, a billion tons of industrial waste, fertilizers and chemical waste were dumped untreated into water bodies, such as rivers, lake and oceans contributing towards water pollution, then threatening human health and ecosystem. Hence, the need for clean water has urged scientists to research and find solutions for improving water quality. Application of nanoparticles in wastewater treatment improves the environmental quality by elimination of harmful pollutants in wastewater. Magnetite is one of the nanoparticles used in wastewater treatment because of its specific large surface area, high reactivity in adsorption and recoverable from treated water via magnetic separation technology. Preparation method of magnetite nanoparticles is the important key to its adsorption efficiency.
Water pollution is a critical management issue, with many rivers and streams draining urban areas being polluted by the disposal of untreated solid waste and wastewater discharge, storm water and agricultural runoff. This has implications for biodiversity, and many rivers in the developing world are now considered compromised. We investigated benthic macroinvertebrate community structure and composition in relation to physico-chemical conditions of the water column and sediments. The study was conducted in an Austral catchment subject to both urban and agricultural pollutants in two different seasons. We assessed whether sediment characteristics were more important drivers of macroinvertebrate community composition than water column characteristics. We expected clear differences in macroinvertebrate community composition and in the associated community metrics due to distinct flow conditions between the two seasons. A combination of multivariate analyses (canonical correspondence analysis (CCA)) and biological indicator analysis were used to examine these patterns. Chironomidae was the most abundant family (>60%) in the upper mainstem river and stream sites. Stream sites were positively associated with CCA axis 2, being characterised by high turbidity and lower pH, salinity, phosphate concentration, channel width and canopy cover. Canopy cover, channel width, substrate embeddedness, phosphate concentration, pH, salinity and turbidity all had a significant effect on macroinvertebrate community composition. Using CCA variation partitioning, water quality was, however, a better predictor of benthic macroinvertebrate composition than sediment chemical conditions. Furthermore, our results suggest that seasonality had little effect on structuring benthic macroinvertebrate communities in this south-eastern zone of South Africa, despite clear changes in sediment chemistry. This likely reflects the relative lack of major variability in water chemistry compared to sediment chemistry between seasons and the relatively muted variability in precipitation between seasons than the more classic Austral temperate climates.
Nitrate is required to maintain the growth and metabolism of plant and animals. Nevertheless, in excess amount such as polluted water, its concentration can be harmful to living organisms such as microalgae. Recently, studies on microalgae response towards nutrient fluctuation are usually limited to lipid accumulation for the production of biofuels, disregarding the other potential of microalgae to be used in wastewater treatments and as source of important metabolites. Our study therefore captures the need to investigate overall metabolite changes via NMR spectroscopy approach coupled with multivariate data to understand the complex molecular process under high (4X) and low (1/4X) concentrations of nitrate ([Formula: see text]). NMR spectra with the aid of chemometric analysis revealed contrasting metabolites makeup under abundance and limited nitrate treatment. By using NMR technique, 43 types of metabolites and 8 types of fatty acid chains were detected. Nevertheless, only 20 key changes were observed and 16 were down regulated in limited nitrate condition. This paper has demonstrated the feasibility of NMR-based metabolomics approach to study the physiological impact of changing environment such as pollution to the implications for growth and productivity of microalgae population.
Landfill leachate is one of the sources of surface water pollution in Selangor State (SS), Malaysia. Leachate volume prediction is essential for sustainable waste management and leachate treatment processes. The accurate estimation of leachate generation rates is often considered a challenge, especially in developing countries, due to the lack of reliable data and high measurement costs. Leachate generation is related to several variable factors, including meteorological data, waste generation rates, and landfill design conditions. Large variations in these factors lead to complicated leachate modeling processes. The aims of this study are to determine the key elements contributing to leachate production and then develop an adaptive neural fuzzy inference system (ANFIS) model to predict leachate generation rates. Accuracy of the final model performance was tested and evaluated using the root mean square error (RMSE), the mean absolute error (MAE), and the correlation coefficient (R). The study results defined dumped waste quantity, rainfall level, and emanated gases as the most significant contributing factors in leachate generation. The best model structure consisted of two triangular fuzzy membership functions and a hybrid training algorithm with eight fuzzy rules. The proposed ANFIS model showed a good performance with an overall correlation coefficient of 0.952.
Water contamination by herbicides and chelating agents is increasing mainly due to the
increasing agricultural activities. Water contamination by these compounds has become a
concern due to their adverse effects to the environment and humans. Seven sampling sites of
water sources in Selangor and Johor were chosen for the study. Contamination level of
Mecoprop (MCCP), Nitrilotriacetic acid (NTA) and Ethylenediaminetetraacetic acid (EDTA) in
these water body areas was determined by using Gas Chromatography-Electron Capture
Detector (GC-ECD). Our results indicated that water samples of Sungai Melot in Selangor
showed the highest presence of EDTA. MCCP was detected at a high level at Sungai Sarang
Buaya, Johor while NTA showed similar level of concentration at three different sites, Ladang
10, Ladang Sayur and Mardi, Selangor.
Population in urban centers in Kenya is increasing rapidly due to rural urban migration in search of better paying jobs. This migration has resulted in unauthorized settlements in the various urban centers. The income per capital of these people is less than a dollar a day. The amount of money is inadequate for survival and this has resulted into cultivating on open grounds for food crops. Unfortunately, these slums have come up along rivers, which carry, wastewater from household and industries. This wastewater is rich in heavy metals and the inhabitants of these areas use this contaminated water for irrigating their crops. The food crops from such areas have very high levels of heavy metals. The present study has screened Zea mays, Commelina bengalensis and Amaranthus hybridus for their ability to bioaccumulate these metals from contaminated soils using atomic absorption spectrophotometer (AAS). The results obtained showed that the C. bengalensis has high potential for removal of Cu, Pb and Cd metals as compared to the Zea mays and Amaranthus hybridus even though, results showed that C. bengalensis has a low potential for the removal of Zn as compared to Zea mays and Amaranthus hybridus.
Occurrence of pharmaceutical residues in drinking water has been widely reported in countries that have registered steady economic growth. This can exert concerns among the general consumers, prompting them to explore the potential human health risks associated with continuous exposure to pharmaceuticals. However, such an occurrence is rarely reported in developing or under-developed countries. To give more contexts, this study looked at the presence of nine pharmaceutical residues in drinking water (amoxicillin, caffeine, chloramphenicol, ciprofloxacin, dexamethasone, diclofenac, nitrofurazone, sulfamethoxazole, and triclosan) at Putrajaya residential area in Malaysia. Additionally, the potential health risks associated with contaminated drinking water were investigated. This study has found the presence of pharmaceutical residue concentrations up to 0.38 ng/L, with the highest concentration of caffeine (0.38 ng/L) and the lowest concentration of diclofenac (0.14 ng/L). In comparison, all the nine pharmaceutical residues were substantially lower than previously reported studies. In general, Hazard Quotient (HQ) values indicated that low potential health hazards were present for all age groups. Nevertheless, quantitative occurrences of pharmaceutical residues in drinking water will help guide future toxicological studies to examine other chronic effects, while canvassing for proper framework to look into the water risk management and regulation in Malaysia.
Water from the dental unit waterlines (DUWLs) is known to contaminate with microbial from the biofilm that formed in the tubing system. The water quality from DUWLs is important to patients and dental health care professionals as they could be infected either directly from the contaminated water or aerosol that is generated during dental procedures. Suppliers claimed that dental units supplied to the hospital can only use a specific disinfectant which is uneconomic compared with the others. The aims of this study were to evaluate and compare the efficacy of different disinfectant on the water quality of DUWLs. Four disinfectants (Calbenium, A-dec ICX tablet, Dentel 5, Metassys) and distil water were evaluated. 350 mL water sample was collected separately, from the outlet of high-speed handpiece, scaler, 3-ways syringe and cup filler into a sterile thiosulfate bag on the 1st, 2nd, 4th, 8th, 12th and 24th weeks of the study. The samples were tested on the following day for total viable count (TVC). There is significant difference in the efficacies of the different disinfectants. Only one disinfectant consistently produces water quality within the recommended level of American Dental Association (ADA). Within the limitation of this study, it was found that there is alternative disinfectant that can reduce the TVC to the level recommended by ADA. However, the water qualities produced with these disinfectants were not consistent although they did not cause any technical problem to the dental units during the period of study.
Heavy metal ion contamination in water poses a significant risk to human health as well as to the environment. Millions of tons of agricultural wastes are produced from oil palm plantations which are challenging to manage. In this study, we converted palm kernel shells (PKS) from a palm oil plantation into activated carbon (AC) having a surface area of 1099 m2/g using phosphoric acid as an activator. The prepared material was characterized using BET, XRD, Raman, FESEM and FTIR analyses. The AC was applied for the treatment of heavy-metal-contaminated water, and different parameters; the pH, adsorbent dosage, contact time and metal ion concentrations were varied to determine the optimal conditions for the metal ion adsorption. Different kinetic models; the zeroth, first-order and second-order, and Freundlich and Langmuir isotherm models were used to determine the mechanism of metal ion adsorption by the AC. Under the optimized conditions, Cr6+ and Pb2+ were removed completely, while Zn2+ and Cd2+ were more than 80% removed. This is a greener approach in which an agricultural waste, PKS is converted into a useful product, activated carbon and subsequently applied for the treatment of heavy metal-contaminated water.
Principal component analysis (PCA) is capable of handling large sets of data. However, lack of consistent method in data pre-treatment and its importance are the limitations in PCA applications. This study examined pre-treatments methods (log (x + 1) transformation, outlier removal, and granulometric and geochemical normalization) on dataset of Mengkabong Lagoon, Sabah, mangrove surface sediment at high and low tides. The study revealed that geochemical normalization using Al with outliers removal resulted in a better classification of the mangrove surface sediment than that outliers removal, granulometric normalization using clay and log (x + 1) transformation. PCA output using geochemical normalization with outliers removal demonstrated associations between environmental variables and tides of mangrove surface sediment, Mengkabong Lagoon, Sabah. The PCA outputs at high and low tides also provided to better interpret information about the sediment and its controlling factors in the intertidal zone. The study showed data pre-treatment method to be a useful procedure to standardize the datasets and reducing the influence of outliers.
Ralstonia mannitolilytica is a gram negative soil bacterium. Ralstonia infection though rare, has become the emerging nosocomial pathogens in hospital settings. Various clinical manifestations had been described as well as the mode of transmission. Despite its low virulence factor, it is able to survive under harsh condition and this may potentially cause significant morbidity and mortality especially in immunocompromised patients. Outbreak of Ralstonia mannitolilytica infections in the hospital are typically associated with contaminated medical supplies or instruments. We described here a case of Ralstonia mannitolilytica infection in a dialysis patient that occurred during the municipal reservoir water contamination crisis. In this report, we will also describe the behaviour of Ralstonia genus and its 4 main species, namely R. pickettii, R. solanacearum, R. insidiosa, and R. mannitolilytica and the choices of antibiotic therapy based on literature review.
A total of 127 and 177 seafood samples from Malaysia were analyzed for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs), respectively. The World Health Organization-toxic-equivalency quotients (WHO-TEQ) of PCDD/Fs varied from 0.13 to 1.03 pg TEQ g(-1), whereas dl-PCBs ranged from 0.33 to 1.32 pg TEQ g(-1). Based on food-consumption data from the global environment monitoring system-food contamination monitoring and assessment programme, calculated dietary exposures to PCDD/Fs and dl-PCBs from seafood for the general population in Malaysia were 0.042 and 0.098 pg TEQ kg(-1) body weight day(-1), respectively. These estimations were quite different from the values calculated using the Malaysian food-consumption statistics (average of 0.313 and 0.676 pg TEQ kg(-1) body weight day(-1) for PCDD/Fs and PCBs, respectively). However, both of the dietary exposure estimations were lower than the tolerable daily intake recommended by WHO. Thus, it is suggested that seafood from Malaysia does not pose a notable risk to the health of the average consumer.
Matched MeSH terms: Water Pollution, Chemical/statistics & numerical data
Polybrominated diphenyl ethers (PBDEs) were measured in surface sediment samples collected from urban canals or rivers in Lao PDR, Cambodia, Vietnam, India, Indonesia, Thailand, the Philippines, Malaysia and Japan. The total PBDE concentrations in the sediments ranged from 0.83 to 3140 ng/g dry wt. BDE-209 was predominant, ranging from 43% to 97% of total PBDEs, followed by nona-BDEs and some detectable concentrations of BDEs 47, 49, 99, 100, 153, 154 and 183. Sedimentary PBDE levels in Malaysia, Cambodia, the Philippines and Thailand were generally higher than those reported for highly industrialized countries. Spatial distribution of PBDEs indicated that inland sources may impact coastal areas. The presence of BDE congeners which are not contained in technical mixtures and the higher proportions of nona-BDEs relative to BDE-209 in the sediments were identified as indicators of debromination. BDE-209 was possibly debrominated under anaerobic conditions in some of the sediment samples.
Matched MeSH terms: Water Pollution, Chemical/statistics & numerical data
We analyzed 68 green and blue mussels collected from Cambodia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Philippines, Vietnam and the USA during 2003 and 2007, to elucidate the occurrence and widespread distributions of emerging pollutants, synthetic musks and benzotriazole UV stabilizers (BUVSs) in Asia-Pacific coastal waters. Synthetic musks and BUVSs were detected in mussels from all countries, suggesting their ubiquitous contamination and widespread distribution. High concentrations of musks and BUVSs were detected in mussels from Japan and Korea, where the levels were comparable or greater than those of PCBs, DDTs and PBDEs. Significant correlations were found between the concentrations of HHCB and AHTN, and also between the concentrations of UV-327 and UV-328, which suggest similar sources and compositions of these compounds in commercial and industrial products. To our knowledge, this is the first study of large-scale monitoring of synthetic musks and BUVSs in Asia-Pacific coastal waters.
Matched MeSH terms: Water Pollution, Chemical/statistics & numerical data
A study on the quality of water abstracted for potable use was conducted in the Selangor River basin from November 2008 to July 2009. Seven sampling sites representing the intake points of water treatment plants in the basin were selected to determine the occurrence and level of 15 organochlorine pesticides (OCPs), six phthalate esters (PAEs) and bisphenol A (BPA). Results indicated OCPs were still detected regularly in 66.1 % of the samples with the Σ(15)OCPs ranging from 0.6-25.2 ng/L. The first data on PAEs contamination in the basin revealed Σ(6)PAEs concentrations were between 39.0 and 1,096.6 ng/L with a median concentration of 186.0 ng/L while BPA concentration ranged from <1.2 to 120.0 ng/L. Although di-n-butyl phthalate was detected in all the samples, concentrations of di-ethyl(hexyl)phthalate were higher. Sampling sites located downstream recorded the highest concentrations, together with samples collected during the dry season. Comparison of the detected contaminants with the Department of Environment Water Quality Index (DOE-WQI) showed some agreement between the concentration and the current classification of stream water. While the results suggest that the sites were only slightly polluted and suitable to be used as drinking water source, its presence is cause for concern especially to the fragile firefly "Pteroptyx tener" ecosystem located further downstream.
Matched MeSH terms: Water Pollution, Chemical/statistics & numerical data