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21.
Concentrations of mercury and arsenic in fish from the Persian Gulf were determined by graphite furnace atomic absorption spectrometry. Concentrations of the metals in muscle samples were 0.049–0.402 μg g?1 for mercury and 0.168–0.479 μg g?1 for arsenic, with means of 0.133 and 0.312 μg g?1, respectively. The maximum daily consumption rate (grams per day) and meal consumption limit (meals per month) was calculated to estimate health risks associated with fish consumption. According to the results, the maximum allowable consumption rate varies between 8–56 and 15–96 g/day base on mercury and arsenic content, respectively. The results of this study indicate that the concentration of mercury and arsenic is well below the maximum permissible levels for mercury (0.5 μg g?1) and arsenic (6 μg g?1) according to international standards.  相似文献   
22.
In order to evaluate the exposure of the northern India rural population to polyaromatic hydrocarbon (PAH) inhalation, indoor pollution was assessed by collecting and analyzing the respirable particulate matter PM2.5 and PM10 in several homes of the village Bhithauli near Lucknow, UP. The home selection was determined by a survey. Given the nature of biomass used for cooking, homes were divided into two groups, one using all kinds of biomass and the second type using plant materials only. Indoor mean concentrations of PM2.5 and associated PAHs during cooking ranged from 1.19 ± 0.29 to 2.38 ± 0.35 and 6.21 ± 1.54 to 12.43 ± 1.15 μg/m3, respectively. Similarly, PM10 and total PAHs were in the range of 3.95 ± 1.21 to 8.81 ± 0.78 and 7.75 ± 1.42 to 15.77 ± 1.05 μg/m3, respectively. The pollutant levels during cooking were significantly higher compared to the noncooking period. The study confirmed that indoor pollution depends on the kind of biomass fuel used for cooking.  相似文献   
23.
The present study investigated the impacts of treated effluent discharge on physicochemical and biological properties of coastal waters from three pharmaceuticals situated along the coast of Visakhapatnam (SW Bay of Bengal). Seawater samples were collected (during the months of December 2013, March 2014 and April 2014) from different sampling locations (Chippada (CHP), Tikkavanipalem (TKP) and Nakkapalli (NKP)) at 0- and 30-m depths within 2-km radius (0.5 km = inner, 1 km = middle and 2 km?=?outer sampling circles) from the marine outfall points. Physicochemical and biological parameters, which differed significantly within the stations, were likely to be influenced by strong seasonality rather than local discharge. Dissolved oxygen variability was tightly coupled with both physical and biological processes. Phytoplankton cell density and total chlorophyll (TChla) concentrations were significantly correlated with dissolved inorganic nutrient concentrations. CHP (December) represented a diatom bloom condition where the highest concentrations of diatom cells, total chlorophyll (TChla), dissolved oxygen coupled with lower zooplankton abundance and low nutrient levels were noticed. The centric diatom, Chaetoceros sp. (>?50%) dominated the phytoplankton community. TKP (March) represented a post-diatom bloom phase with the dominance of Pseudo-nitzschia seriata; zooplankton abundance and nutrient concentrations were minimum. Conversely, NKP (April) represented a warm well-stratified heterotrophic period with maximum zooplankton and minimum phytoplankton density. Dinoflagellate abundance increased at this station. Relatively higher water temperature, salinity, inorganic nutrients coupled with very low concentrations of dissolved oxygen, TChla and pH were observed at this station. Copepods dominated the zooplankton communities in all stations and showed their highest abundance in the innermost sampling circles. Treated effluent discharge did not seem to have any significant impact at these discharge points.  相似文献   
24.
25.
Paper mill wastewater leads to a serious damage on the environment owing to the high content of organic matters, suspended solids, toxic substances, and lignin. Hence, exploring new treatment technologies is the passion of environmental engineers to minimize the effluent impact on the environment and cleaner production aspects. This research focused on the performance of full-scale coagulation-fluctuation/DAF system for pre-treatment of high strength wastepaper-recycling wastewater and its effect on biodegradability improvement. To optimize unit performance, optimum coagulant and flocculant doses were firstly determined by jar test without prior change and adjustment of pH in lab-scale experiments. The optimum dosages were obtained by 1500 mg L?1 polyaluminum chloride (PACl) as coagulant coupled with 40 mg L?1 cationic polyacrylamide (C-PAM) as flocculant. Percentage removals of 39?±?10, 6.8?±?3.6, 31.0?±?6.7, 24.0?±?3.8, and 33.0?±?20.0 were achieved for COD, sCOD, BOD5, sBOD5, and color, respectively. The average BOD5 to COD ratio after pre-treatment increased from 0.44 to 0.5, whereas the ratio of sBOD5/sCOD dropped from 0.65 to 0.53. A superior effectiveness in reduction of TSS (98.1%) and VSS (98.4%) was also achieved. The results show that the application process is able to prevent malfunction operation in the following bioreactors which is obtainable through bio-treatability enhancement of pre-treated wastewater and reducing the risks of clogging and sludge washout. Attached growth processes are suggested to be applied in the further anaerobic/aerobic processes because of high proportion of soluble fraction of COD in the effluent to avoid poor floc formation and dispersed growth problems.  相似文献   
26.
Work-related traumatic forestry and sawmill fatalities were studied as part of a larger study of all work-related traumatic fatalities in Australia from 1982 to 1984. Data on 79 cases were obtained from inspection of coroners' files. The fatality incidence per 100,000 person-years was extremely high for loggers (396), and high for forest service workers (52) and workers employed in sawmills (30), compared to the entire Australian workforce (8.1). Felling/trimming trees, traffic-related activities and operating heavy machinery (forestry workers) and loading/unloading logs and operating bench saws (sawmill workers) were the most common tasks being performed at the time of the fatal injury. Being struck by a falling tree, often one that had been disturbed by the tree being felled, was the most common mechanism of fatal injury. Isolation, poor work practice, errors of judgement, and equipment problems were the most common contributing factors to the fatal incidents. Emphasis on correct work practice and training (especially in felling), equipment maintenance, and availability of communication and medical retrieval in isolated areas are recommended.  相似文献   
27.
Five week-old mice were divided into a vehicle control group, and groups exposed to ZnO nanoparticles at low (0.5 g/kg), middle (1 g/kg), high (3 g/kg), and exceptionally high-dose (5 g/kg). After the first, second, third, and fourth weeks’ of exposure, blood biochemistry, histopathology, and electron microscopic ultrastructural changes in liver, kidney and spleen were investigated. Increased alkaline phosphatase activities were observed in all treated mice being statistically significant at higher dose. No changes were observed in the serum glutamic pyruvic transaminase, serum glutamic oxaloacetic transaminase, creatinine, blood urea nitrogen, and lipid levels. During the first and second weeks of the treatment, effects on the cytoarchitecture of liver, kidney, and spleen were not perceived while during the third and fouth weeks of treatment sporadic mild effects were seen. Ultrastructural electron microscopic changes in liver, kidney, and spleen were not observed for the low-dose group on the first, second, third, and fourth weeks, suggesting that exposure to ZnO nanoparticles at low dose is safe. Long-term (i.e., more than 28 days) exposure to the exceptionally high-dose resulted in sporadic changes in nuclear chromatin condensation, irregular nuclear membrane, polymorphic mitochondria, mitochondrial swelling, and vacuolation. ZnO nanoparticles could be well tolerated and no death occurred in any group of treated mice.  相似文献   
28.
This paper assesses the cost-effectiveness of, and the return on the investment in, the 2002 catch-up and the 2003 follow-up measles campaigns in Afghanistan from the perspective of the donor. The catch-up campaign targeted nearly 12 million children aged between six months and 12 years, while the follow-up campaign targeted over five million children aged between 9 and 59 months. Both campaigns successfully vaccinated approximately 96 per cent of the respective target populations, and are expected to avert an estimated 301,000 measles deaths over the next 10 years. The average cost per dose of measles vaccine delivered was USD 0.40. The cost per death prevented is USD 23.6, assuming a case fatality rate of 10 per cent and a discount rate of three per cent. With more than 42,000 measles deaths avoided for every one million US dollars spent, the campaigns are an excellent public health investment for precluding childhood mortality in a country affected by a complex emergency.  相似文献   
29.
Wastewater and soil samples were collected from the industrial area of Ghaziabad City, India from January 2005 to December 2007 and were analyzed for the presence of heavy metals by atomic absorption spectrophotometry. Test samples revealed high levels of Fe, Cr, Cu, Ni, Zn, and Cd as 967.03, 34.63, 27.97, 19.7, 16.70, and 3.20 mg/L of wastewater, respectively. The concentrations of inorganic minerals were higher in the soil samples irrigated with wastewater. Total coliforms were found to be maximum (1,133 × 104 most probable number per 100 mL) during spring and summer followed by winter and postmonsoon in the wastewater samples. The microbial count in soil as well as in wastewater decreases as the metal concentration increases. The concentration 200 μg/mL of nickel and cadmium inhibits majority of the population, while, at some points, it inhibits 100% of the population. The exponential decay model for microbial count at the increasing metal concentrations indicate that asymbiotic N2 fixers were best fitted to the model. In all the seasons, the order of decline in terms of exponential decay of the population of different microbial groups in soil was asymbiotic N2 fixers > actinomycetes > fungi > aerobic heterotrophic bacteria. The different microbial groups that have different values of slope in different seasons indicate that the resistant population of microorganisms was variable with seasons.  相似文献   
30.
On 27 July 2003, Tasman Spirit spilled 31,000 tonnes of crude oil into the sea at the Karachi coast. This disaster badly affected the marine life (Flora and Fauna.) Present research has been proposed to ascertain the level of Polycyclic Aromatic hydrocarbons (PAHs) contamination in different fisheries including Fishes, Crustaceans; Crabs and Shrimps, Mollusks and Echinoderms along with passing time. Heavier components of crude oil such as Polycyclic Aromatic Hydrocarbons (PAHs) appear to cause most damages as these are relatively unreactive and persist in water. High concentrations of toxic PAHs were observed in all the fisheries and shellfishes caught form oil-impacted area. In this study fishes were found most contaminated than shellfishes i.e. summation operator 16 PAH = 1821.24 microg/g and summation operator 1164.34 microg/g, respectively. Naphthalene was found in the range of 0.042-602.23 microg/g. Acenaphthylene, acenaphthene, fluorene, phenanthrene and anthracene were detected in the range 0.008-80.03 microg/g, fluoranthene, pyrene, benzo(a)anthracene and chrysene 0.0008-221.32 microg/g, benzo(b) fluoranthene, benzo(k)fluoranthene and benzo(a) pyrene 0.0005-7.71 microg/g, benzo(g,h,i)perylene and indeno(1,2,3-c,d)pyrene 0.02-503.7 microg/g. Dibenzo(a,h)anthracenre was not detected in any specie.  相似文献   
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