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41.
The purpose of this study was to evaluate the efficiency of the recent (2006) European Union Directive concerning the management of bathing water quality to exclude the presence of pathogens from complying waters. Coastal water samples were classified according to the Directive. 2.5% of ‘excellent’ water contained Salmonella and 39.2% Candida albicans 11.8% of samples in category ‘good’ were Salmonella positive and 35.2% were C.albicans positive. When the USEPA criterion for marine waters was applied to the same dataset, fewer samples complied, however 6.0% of the complying samples contained Salmonella. The results suggest that the bacterial indicator threshold levels for marine recreational water quality of the 2006/7/EC European Union Directive do not fully exclude contact of bathers with dangerous pathogens. Enterococci, if used as the sole index, appear to form a more reliable proxy of the risk of contact with Salmonella. 相似文献
42.
Four small freshwater river systems in Hessen, Germany, have been investigated with respect to seasonal and spatial concentration variations and transported load of the organophosphates tri‐n‐butyl phosphate (TBP), tris(2‐butoxyethyl)phosphate (TBEP), tris(2‐chloroethyl)phosphate (TCEP), tris(1‐chloro‐2‐propyl)phosphate (TCPP), and tris(1,3‐dichloro‐2‐propyl)phosphate (TDCPP) and the synthetic musk fragrances 1,3,4,6,7,8‐hexahydro‐4,6,6,7,8,8‐hexa‐methylcyclopenta‐[γ]‐2‐benzopyran (HHCB) and 7‐acetyl‐1,1,3,4,4,6‐hexamethyl‐1,2,3,4‐tetrahydronaphthalene (AHTN). Data originate from water samples collected in the time span from September 2003 to April 2005 at 25 sampling locations. The detection frequency for all compounds was about 90%. Mean concentration levels of organophosphates were 502 ng/L (TCPP), 276 ng/L (TBP), 183 ng/L (TBEP), 118 ng/L (TCEP), and 117 ng/L (TDCPP). The synthetic musk fragrances HHCB and ATHN were detected with mean concentrations of 141 and 46 ng/L, respectively. The variability of the concentration of all compounds was high with respect to space and time. The highest concentrations were observed in the Schwarzbach system characterized by the highest proportion of wastewater compared to the other river systems. Concentration levels of synthetic musk fragrances were significantly lower in summer times compared to winter times. 相似文献
43.
The feasibility of pilot‐scale mineralization of organic pollutants in wastewaters using the Electro‐Fenton® process is demonstrated. The treatment was applied in a continuous‐flow reactor, to solutions of nitrobenzene, 2,4‐D and benzoic acid and to actual wastewaters from a fine chemicals company along with a pulp and paper company. The results showed mineralization yields from 60 to 84% by simply applying the Electro‐Fenton® process. When a subsequent exposure to sunlight was carried out (Helielectro‐Fenton method), this mineralization almost went to completion, except for the effluent from the fine chemicals industry. 相似文献
44.
针对浙江省奉化市粮食局米厂大米车间、粮库基础托换和锅炉房基础加固工程 ,成功地应用树根桩基础托换技术 ,使沉降和裂缝得到有效控制 ,危房再现使用价值 相似文献
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46.
Heavy metals in sediments of the Tecate River, Mexico 总被引:1,自引:0,他引:1
F. T. Wakida D. Lara-Ruiz J. Temores-Peña J. G. Rodriguez-Ventura C. Diaz E. Garcia-Flores 《Environmental Geology》2008,54(3):637-642
Ten sites along the Tecate River, Mexico were sampled to evaluate the cadmium, lead, nickel and chromium concentrations in
sediments. The result shows contamination for cadmium in most of the sites, where two sites were class 4 (polluted to strongly
polluted) according to geoaccumulation index proposed by Muller. Two sites were found polluted for all the heavy metals analyzed
(Cr, Cd, Pb and Ni), indicating the effect of anthropogenic activities. A correlation between Ni and Cd concentration had
been found indicating a common source. These metals are usually used in electroplating industry. The results of this study
can be used for decision makers to prioritize measures to control the pollution for these metals. 相似文献
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49.
Effect of Mixtures of Heavy Metals on the Biological Treatment of Sewages Containing Naphthalenesulfonic Acid Biological wastewater treatment processes can be destabilized considerably by heavy metals. In this investigation, the effect of loadings of heavy metals on the degradation of naphthalene-2-sulfonic acid (2NS) by immobilized bacteria in continuously operated airlift-loop reactors was studied. Shock loadings with mixtures of cadmium and nickel, or cadmium and zinc, respectively, resulted in increases in inhibition compared to those observed with the single metals. In contrast, the 2NS-degradation was less inhibited by shock loadings with mixtures of nickel and zinc than by the single metal ions. Repeated shock loadings up to 100 mg L?1 nickel and 1000 mg L?1 zinc effected an adaptation of the microorganisms. Continuous loadings with up to 10 mg L?1 cadmium and nickel each, or with 50 mg L?1 nickel and 210 mg L?1 zinc, respectively, did not inhibit the degradation of 2NS. The permanent loadings led to an adaptation of the bacteria with an increased biosynthesis of proteins from 0.2 to 0.5 g g?1 cell dry weight. However, if the immobilized cells were incubated with mixtures of cadmium and nickel, the specific polysaccharide content decreased to less than 0.2 g g?1 cell dry weight, resulting in a detachment of the biofilms. 相似文献
50.
Electrochemical Characterization of the Surface of Activated Carbon Used in Water Treatment Plants. We tried to measure electrochemically those properties of activated carbons which are important for using them for water purification. A success was achieved with the electrochemical immersion potential Ui which is found to be a function of concentration of functional surface groups on the carbon surface. However, the expected direct proportionality for inert surfaces between BET surface area and amount of charge measured in recharge processes has not been observed. 相似文献