Current Issue : July - September Volume : 2012 Issue Number : 3 Articles : 7 Articles
Aerobic spherical granules were observed in zeolitic dual-layer intermittent percolating filters treating domestic septic tank effluent. The diameter of the granules ranged from 0.05 to 0.5 mm and when they predominate in the biofilms the mean SVI value was of 54 ml g-1 instead of 232 ml g-1 when they were absent.\r\n Flow behavior in these filters was characterized by the dimensionless Reynolds number. The values obtained (40 less than Re less than 60) were representative of intermediate flow conditions and invalidated the current hypothesis of laminar flow conditions. These values were of the magnitude of those estimated from studies on SBR reactors presenting granular sludge formation.\r\n The possible influence of granular sludge formation on long-term performances and interfacial clogging of intermittent dual-layer percolating filters is also discussed....
Background: Benzene, formaldehyde and acetaldehyde are carcinogenic substances to which gasoline station workers are most likely\r\nexposed via inhalation. To evaluate these compounds in the ambient air of gasoline stations, the inhalation exposure test on workers was\r\nperformed and assessed. By the appropriate intervention of wearing mask and hand washing during work shift, we determined whether or\r\nnot there is cancer risk to the exposure of benzene, formaldehyde and acetaldehyde using urinary biomarkers.\r\nMethods: A cross sectional study was conducted in 38 workers of 6 gasoline stations in Pathumwan District, Bangkok, Thailand. Inhalation\r\nand ambient air concentrations of benzene, formaldehyde and acetaldehyde were evaluated by GC/FID and HPLC/UV detectors. Urinary\r\ntrans, trans-muconic acid (t,t-MA), formaldehyde and acetaldehyde concentrations detected in gasoline workers before and after\r\nappropriate intervention were analyzed by GC/FID.\r\nResults: The average inhalation exposure concentrations of benzene, formaldehyde and acetaldehyde were 195.56, 12.60 and 5.74 �µg/m3,\r\nrespectively. The level of benzene exposure was significantly higher than the ambient air level (independent t-test, p < 0.01). The average\r\nlifetime cancer risk of the workers exposed to benzene, formaldehyde and acetaldehyde was determined at the values of 2.15E-04, 1.27E-05\r\nand 2.69E-06, respectively. Benzene and formaldehyde values were higher than an acceptable criteria defined as 1E-06. The amount of\r\nurinary t,t-MA, formaldehyde and acetaldehyde in the workers daily after 7-days appropriate intervention (wearing masks as personal\r\nprotective equipment (PPE) and hand washing) was decreased. Formaldehyde and acetaldehyde, which were detected in urine, showed\r\nsignificantly lower than before intervention (pair t-test, p < 0.001).\r\nConclusions: Results from our study confirmed that the gasoline workers have high chances of cancer risk from daily exposure to benzene\r\nand formaldehyde. The urinaryâ��s t,t-MA, formaldehyde and acetaldehyde could be considerably used as biomarkers in gasoline station\r\nworkers. An appropriate intervention, using PPE and hand washing, could reduce the cancer risk....
Electrochemical behavior of azo dyes, Fast Sulphon Black F (FSB-F) and Eriochrome Black T (EBT) was performed with cyclic voltammetry in sulphuric acid medium using glassy carbon as working electrode. The redox potentials observed at -230mV and -300mV for FSB-F and EBT respectively. Electrochemical degradation of dyes assessed by means of the application of DC current. However, complete degradation was achieved for both FSB-F and EBT. The decolourisation efficiency was assessed through UV-Vis studies. The Liquid Chromatograms of the dyes were analyzed before and after electrochemical treatment and confirmed that the azo groups and aromatic rings were destroyed. The effect of pH and nature of supporting electrolytes on the electrochemical degradation of the dyes were also studied. The maximum Chemical Oxygen Demand (COD) removal was 100% for the dye solutions at 15gL-1 of NaCl concentration. The results revealed that the suitability of the present process will effectively degrade the dye effluents....
Background: Despite the increase of mobile phone use in the last decade and the growing concern whether mobile\r\ntelecommunication networks adversely affect health and well-being, only few studies have been published that focussed\r\non children and adolescents. Especially children and adolescents are important in the discussion of adverse health effects\r\nbecause of their possibly higher vulnerability to radio frequency electromagnetic fields.\r\nMethods: We investigated a possible association between exposure to mobile telecommunication networks and wellbeing\r\nin children and adolescents using personal dosimetry. A population-based sample of 1.498 children and 1.524\r\nadolescents was assembled for the study (response 52%). Participants were randomly selected from the population\r\nregistries of four Bavarian (South of Germany) cities and towns with different population sizes. During a Computer\r\nAssisted Personal Interview data on participants'' well-being, socio-demographic characteristics and potential confounder\r\nwere collected. Acute symptoms were assessed three times during the study day (morning, noon, evening).\r\nUsing a dosimeter (ESM-140 Maschek Electronics), we obtained an exposure profile over 24 hours for three mobile\r\nphone frequency ranges (measurement interval 1 second, limit of determination 0.05 V/m) for each of the participants.\r\nExposure levels over waking hours were summed up and expressed as mean percentage of the ICNIRP (International\r\nCommission on Non-Ionizing Radiation Protection) reference level.\r\nResults: In comparison to non-participants, parents and adolescents with a higher level of education who possessed a\r\nmobile phone and were interested in the topic of possible adverse health effects caused by mobile telecommunication\r\nnetwork frequencies were more willing to participate in the study. The median exposure to radio frequency\r\nelectromagnetic fields of children and adolescents was 0.18% and 0.19% of the ICNIRP reference level respectively.\r\nConclusion: In comparison to previous studies this is one of the first to assess the individual level of exposure to mobile\r\ntelecommunication networks using personal dosimetry, enabling objective assessment of exposure from all sources and\r\nlonger measurement periods. In total, personal dosimetry was proofed to be a well accepted tool to study exposure to\r\nmobile phone frequencies in epidemiologic studies including health effects on children and adolescents....
Background: An Australian company called Lynas Corporation is building the worldââ?¬â?¢s largest rare earth extraction plant at Gebeng near\r\nthe city of Kuantan in Malaysia. This project is very controversial in Malaysia because of fears about possible negative health,\r\nenvironmental and economic impacts once the plant begins operation.\r\nMethods: Material was gathered through mass media reports, official Lynas Corporation publications and press releases, and public\r\nstatements as well as personal communication with opponents of the plant.\r\nResults: Lynas Corporation, backed by public authorities such as the government of the state of Pahang of which Kuantan is the capital\r\ncity, claims that the plant is not a threat to public health; the wastes generated can be disposed of safely; and that the economic benefits\r\nwill be substantial. Critics argue that the wastes produced will be in huge amounts and they will be a grave threat to health because the\r\nwastes would include radioactive thorium and uranium. Critics also claim that the methods of waste processing and disposal being\r\nproposed by Lynas Corporation are deplorable and irresponsible. Furthermore, contrary to the assertions of Lynas Corporation, the\r\neconomic benefits are dubious because of the twelve year tax holiday granted by the Malaysian authorities, the low number of jobs that\r\nwill be created, and the negative impact that the project is already exerting on property values in the Kuantan region.\r\nConclusions: Citizen resistance to the project is ongoing and fierce. In mid-March 2012, the project is still at an impasse. A ââ?¬Å?temporary\r\noperating licenseââ?¬Â has been granted by the Malaysian authorities but the situation remains unclear because the Lynas plant is still under\r\nconstruction and opponents are taking legal action in order to stop it from operating when it is finished. It remains to be seen if this\r\nrelatively rare mobilization of ââ?¬Å?people powerââ?¬Â in politically authoritarian Malaysia will be able to defeat state-backed transnational\r\ncorporate power....
not available...
We developed a model correlating Advanced Very High Resolution Radiometer (AVHRR)-based Temperature \r\nCondition Index (TCI) and Vegetation Condition Index (VCI) with potato yield in Bangladesh. Weekly TCI and VCI \r\nIndices for 1993ââ?¬â??2005 along with official potato yield statistics were used for model development. We found a strong \r\ncorrelation between inter annual variation in potato yield and TCI and VCI during the critical period of potato growth \r\n(vegetative phase and tuber initiation), mid-December to mid-January. Principal component regression (PCR) was \r\nused to construct a model to predict potato yield as function of TCI and VCI. The model explained about 75% of yearto-year variation in potato yield. Remote sensing offers valuable and readily obtainable information on potato yield well \r\nin advance of harvest....
Loading....