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41.
42.
The assessment of sediment screening risk in Venice Lagoon and other coastal areas using international sediment quality guidelines 总被引:3,自引:0,他引:3
Sabine E. Apitz Andrea Barbanti Alberto Giulio Bernstein Martina Bocci Eugenia Delaney Laura Montobbio 《Journal of Soils and Sediments》2007,7(5):326-341
Background, Aims and Scope A number of studies carried out in recent years have shown the presence of a wide range of contaminants in the Venice Lagoon.
It is important to have a good understanding of the ecological quality of Venice Lagoon sediments, in order to: i) define
and locate areas where a threat to the environment is present and therefore an intervention is needed (i.e. in situ assessment and management); and ii) define sustainable and environmentally correct ways of managing sediments which are to
be dredged for navigational purposes or in relation to other interventions (i.e., ex situ management).
Methods To examine how various regional and international SQGs ‘classed’ screening risk in Venice Lagoon sediments, data on median
contaminant levels in surface sediments in Venice Lagoon resulting from a literature review were compared to a range of local
and international sediment quality guidelines (SQGs). Then data on sediment contaminant levels in various areas and sub-basins
of Venice Lagoon (main Lagoon, Porto Marghera and Venice City Canals) and in other regional and international transitional
and coastal ecosystems with various levels of human impact (urbanization and industrialization) were evaluated based upon
a selected consensus-based SQG. Finally, screening sediment quality for all of Venice Lagoon was mapped and contoured, relative
to this consensus-based SQG and briefly compared with direct toxicity measurement through a battery of bioassays.
Results SQGs allow the sediment areas to be put in terms of potential, or screening, risk. Although there were some differences depending
upon which specific SQGs were applied, the Venice SQGs and other international SQGs provided the same general picture of screening
risk in Venice Lagoon despite geographic differences. Venice Lagoon South has the lowest screening risk levels, Venice Lagoon
Central/North has the highest (and is nearest to the Porto Marghera and Venice City Canals sites).
Discussion The Venice Lagoon sediments have hazard quotients on the low end of the range of moderately urbanized and industrialized sites
and higher than background case studies reviewed. Hg levels in the Venice Lagoon were generally higher than equivalent sites,
while other contaminants were either equivalent or lower. In Porto Marghera (PM) and Venice City Canals (VC), for many contaminants
of interest, PM, and for some, VC sediments have the highest levels of any case study reviewed. Ranges are high, so in all
cases, remedial or disposal decisions should be based upon site-specific (and preferably tiered) data.
Conclusions The use of hazard quotients makes it possible to compare screening risks due to different mixes of contaminants within and
between sites, but results should be interpreted with caution. How these sites rank when compared to some of the other highly
industrialized sites depends upon how data are synthesized and communicated. Actual risk must be evaluated using a weight
of evidence (WOE) approach, as site-specific bioavailability and background levels will differ both regionally and internationally.
Recommendations and Perspectives Whilst there are subtle differences, the current Venice sediment classifications (A, B and C) ‘performed’ in a similar manner
to SQGs in similar classes, suggesting that regions of Venice Lagoon would not be classified much differently if other SQGs
such as TEL, ERL, PEL, ERM or AET were adopted. The Italian sediment quality objectives, on the other hand, are significantly
more conservative than any other SQGs examined, with the exception of the Flemish Reference values. A number of European nations
are considering criteria based upon contaminant levels in relatively pristine modern sites, or based upon derivations of historical
(pre-anthropogenic) contaminant levels. When used as a standard, such an approach lacks discriminating power, designating
almost all sediments within an urbanized or industrialized region as of concern, or even, in many cases, mandating action
or prohibiting various management approaches in a large percentage of sediments. While generally based upon the laudable desire
to return sites to unimpacted levels, there is a risk that overprotective criteria have the opposite effect: by designating
too large a percentage of sediments as requiring management or control, limited resources may be improperly allocated. Which
set of SQGs is most ‘appropriate’ for the Venice Lagoon sediments depends upon the questions being asked. However, the Venice
classifications are currently being used as pass-fail criteria, without consideration of site-specific conditions. The fact
that they performed similarly to SQGs in similar classes suggests that any work to develop more site-specific SQGs (with the
same general decision classes) would probably not make much difference in how sediments were ultimately classified and managed
unless the fundamental approach was changed from a pass-fail to a tiered and WOE approach integrated in a comprehensive decision
framework. For Venice Lagoon, and for other regions, although SQGs should be developed with care, in a scientifically defensible
and risk-based manner, an equally or more important issue to be addressed is their role in overall decision frameworks.
ESS-Submission Editor: Dr. Marc Babut (marc.babut@cemagref.fr) 相似文献
43.
SJ McClure 《New Zealand veterinary journal》2013,61(2):102-108
AIM: To evaluate and compare the effects of a variety of diets on the resistance of young, lightweight Merino lambs to repeated low-dose infections of Trichostrongylus colubriformis. METHODS: Ninety-six 12-week-old lambs were fed balanced or unbalanced diets, and given primary (at 19 weeks of age) or both primary (at 12 weeks) and secondary (at 19 weeks) infections of T. colubriformis. Suboptimal diets were low in total intake, rumen undegradable protein, total protein, readily available carbohydrate or minerals, or supplemented with cod liver oil. Liveweight was monitored fortnightly, protection was assessed from worm counts at the end of the study (25 weeks) and faecal nematode egg counts (FEC) conducted weekly, and mast-cell response assessed at the conclusion of the study from concentration of mast-cell protease in the jejunum. Concentrations of glucose in plasma were measured at 21 weeks. RESULTS: Diets unbalanced for total protein, readily available carbohydrate, Mo or cod liver oil each increased the worm counts after 6 weeks of secondary infection (at 25 weeks of age) and FEC during secondary infection. Low intake of a highnutrient diet restricted liveweight gain but did not affect the development of resistance, as indicated by worm counts and FEC. Defi ciency of available carbohydrate resulted in reduced liveweight gain and reduced concentration of glucose in plasma. There was a reduction in jejunal mast-cell protease concentration in sheep fed unbalanced rations. CONCLUSIONS: The parasitology results and reduction in the concentration of jejunal mast-cell protease observed in sheep fed unbalanced rations suggest that the nutrient defi ciencies and the fi sh-oil supplement may have acted via inhibition or retardation of the host's acquired immune response. Diets unbalanced for a range of components adversely affected the acquired protective response to T. colubriformis to a similar extent and appeared to involve a similar mechanism as each other. The quality of the diet was more important than quantity for the development of resistance, and soluble carbohydrate was an essential component. 相似文献
44.
JR Delaney DS Kelley MD Lilley DA Butterfield JA Baross WSD Wilcock RW Embley M Summit 《Science (New York, N.Y.)》1998,281(5374):222-230
Seafloor diking-eruptive events represent the irreducible, quantum events of upper oceanic crustal accretion. They record events by which a large portion of the oceanic crust has formed through geological history. Since 1993, the U.S. Navy's real-time Sound Surveillance System has allowed location of ongoing acoustic signatures of dike emplacement and basalt eruptions at ridge crests in the northeast Pacific. These diking-eruptive events trigger a sequence of related, rapidly evolving physical, chemical, and biological processes. Magmatic volatiles released during these events may provide nutrients for communities of subseafloor microorganisms, some of which thrive in high-temperature anaerobic environments. Many of the organisms identified from these systems are Archaea. If microorganisms can thrive in the water-saturated pores and cracks within deep, volcanically active portions of our planet, other hydrothermally active planets may harbor similar life forms. 相似文献
45.
The free modulation of interlayer distance in a layered high-transition temperature (high-Tc) superconductor is of crucial importance not only for the study of the superconducting mechanism but also for the practical application of high-Tc superconducting materials. Two-dimensional (2D) superconductors were achieved by intercalating a long-chain organic compound into bismuth-based high-Tc cuprates. Although the intercalation of the organic chain increased the interlayer distance remarkably, to tens of angstroms, the superconducting transition temperature of the intercalate was nearly the same as that of the pristine material, suggesting the 2D nature of the high-Tc superconductivity. 相似文献
46.
Magnetic Field and Plasma Observations at Mars: Initial Results of the Mars Global Surveyor Mission 总被引:2,自引:0,他引:2
MH Acu?a JEP Connerney P Wasilewski RP Lin KA Anderson CW Carlson J McFadden DW Curtis D Mitchell H Reme C Mazelle JA Sauvaud C d'Uston A Cros JL Medale SJ Bauer P Cloutier M Mayhew D Winterhalter NF Ness 《Science (New York, N.Y.)》1998,279(5357):1676-1680
The magnetometer and electron reflectometer investigation (MAG/ER) on the Mars Global Surveyor spacecraft has obtained magnetic field and plasma observations throughout the near-Mars environment, from beyond the influence of Mars to just above the surface (at an altitude of approximately 100 kilometers). The solar wind interaction with Mars is in many ways similar to that at Venus and at an active comet, that is, primarily an ionospheric-atmospheric interaction. No significant planetary magnetic field of global scale has been detected to date (<2 x 10(21) Gauss-cubic centimeter), but here the discovery of multiple magnetic anomalies of small spatial scale in the crust of Mars is reported. 相似文献
47.
SJ More 《Australian veterinary journal》1999,77(12):813-813
48.
49.
50.
The equine industries in Ireland are vibrant and growing. They are broadly classified into two sectors: Thoroughbred racing, and sports and leisure. This paper describes these sectors in terms of governance, education and training in equine welfare, and available data concerning horse numbers, identification, traceability and disposal. Animal welfare, and specifically equine welfare, has received increasing attention internationally. There is general acceptance of concepts such as animal needs and persons' responsibilities toward animals in their care, as expressed in the 'Five Freedoms'. As yet, little has been published on standards of equine welfare pertaining to Ireland, or on measures to address welfare issues here. This paper highlights the central role of horse identification and legal registration of ownership to safeguard the health and welfare of horses. 相似文献