| 1. |
- Formiga-Cruz, M, et al.
(författare)
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Evaluation of potential indicators of viral contamination in shellfish and their applicability to diverse geographical areas.
- 2003
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 69:3, s. 1556-63
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of the concentration of potential indicators of fecal viral pollution in shellfish was analyzed under diverse conditions over 18 months in diverse geographical areas. These microorganisms have been evaluated in relation to contamination by human viral pathogens detected in parallel in the analyzed shellfish samples. Thus, significant shellfish-growing areas from diverse countries in the north and south of Europe (Greece, Spain, Sweden, and the United Kingdom) were defined and studied by analyzing different physicochemical parameters in the water and the levels of Escherichia coli, F-specific RNA bacteriophages, and phages infecting Bacteroides fragilis strain RYC2056 in the shellfish produced, before and after depuration treatments. A total of 475 shellfish samples were studied, and the results were statistically analyzed. According to statistical analysis, the presence of human viruses seems to be related to the presence of all potential indicators in the heavily contaminated areas, where E. coli would probably be suitable as a fecal indicator. The F-RNA phages, which are present in higher numbers in Northern Europe, seem to be significantly related to the presence of viral contamination in shellfish, with a very weak predictive value for hepatitis A virus, human adenovirus, and enterovirus and a stronger one for Norwalk-like virus. However, it is important to note that shellfish produced in A or clean B areas can sporadically contain human viruses even in the absence of E. coli or F-RNA phages. The data presented here will be useful in defining microbiological parameters for improving the sanitary control of shellfish consumed raw or barely cooked.
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| 2. |
- Formiga-Cruz, M, et al.
(författare)
-
Evaluation of potential indicators of viral contamination in shellfish and their applicability to diverse geographical areas
- 2003
-
Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 69:3, s. 1556-1563
-
Tidskriftsartikel (refereegranskat)abstract
- The distribution of the concentration of potential indicators of fecal viral pollution in shellfish was analyzed under diverse conditions over 18 months in diverse geographical areas. These microorganisms have been evaluated in relation to contamination by human viral pathogens detected in parallel in the analyzed shellfish samples. Thus, significant shellfish-growing areas from diverse countries in the north and south of Europe (Greece, Spain, Sweden, and the United Kingdom) were defined and studied by analyzing different physicochemical parameters in the water and the levels of Escherichia coli, F-specific RNA bacteriophages, and phages infecting Bacteroides fragilis strain RYC2056 in the shellfish produced, before and after depuration treatments. A total of 475 shellfish samples were studied, and the results were statistically analyzed. According to statistical analysis, the presence of human viruses seems to be related to the presence of all potential indicators in the heavily contaminated areas, where E. coli would probably be suitable as a fecal indicator. The F-RNA phages, which are present in higher numbers in Northern Europe, seem to be significantly related to the presence of viral contamination in shellfish, with a very weak predictive value for hepatitis A virus, human adenovirus, and enterovirus and a stronger one for Norwalk-like virus. However, it is important to note that shellfish produced in A or clean B areas can sporadically contain human viruses even in the absence of E. coli or F-RNA phages. The data presented here will be useful in defining microbiological parameters for improving the sanitary control of shellfish consumed raw or barely cooked.
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| 3. |
- Palacios, M.A., et al.
(författare)
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Platinum-group elements: quantification in collected exhaust fumes and studies of catalyst surfaces
- 2000
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Ingår i: The Science of the Total Environment. ; 257, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- Automotive catalytic converters, in which Pt, Pd and Rh (platinum-group elements; PGEs) are the active components for eliminating several noxious components from exhaust fumes, have become the main source of environmental urban pollution by PGEs. This work reports on the catalyst morphology through changes in catalyst surface by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) and laser-induced breakdown spectrometry (LIBS) from fresh to aged catalytic converters. The distribution of these elements in the fresh catalysts analysed (PtPdRh gasoline catalyst) is not uniform and occurs mainly in a longitudinal direction. This heterogeneity seems to be greater for Pt and Pd. PGEs released by the catalysts, fresh and aged 30 000 km, were studied in parallel. Whole raw exhaust fumes from four catalysts of three different types were also examined. Two of these were gasoline catalysts (PtPdRh and PdRh) and the other two were diesel catalysts (Pt). Samples were collected following the 91441 EUDC driving cycle for light-duty vehicle testing. The results show that at 0 km the samples collected first have the highest content of particulate PGEs and although the general tendency is for the release to decrease with increasing number of samples taken, exceptions are frequent. At 30 000 km the released PGEs in gasoline and diesel catalysts decreased significantly. For fresh gasoline catalysts the mean of the total amount released was approximately 100, 250 and 50 ng km−1 for Pt, Pd and Rh, respectively. In diesel catalysts the Pt release varied in the range 400800 ng km−1. After ageing the catalysts up to 30 000 km, the gasoline catalysts released amounts of Pt between 6 and 8 ng km−1, Pd between 12 and 16 ng km−1 and Rh between 3 and 12 ng km−1. In diesel catalysts the Pt release varied in the range 108150 ng km−1. The soluble portion of PGEs in the HNO3 collector solution represented less than 5% of the total amount for fresh catalysts. For 30 000 km the total amount of soluble PGEs released was similar or slightly higher than for 0 km.
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