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351.
Since the 1990s there have been a number of government and market led initiatives to improve the welfare of layer hens in the United Kingdom, Australia and the USA. The focus of these regulatory and market initiatives has been a shift away from the dominant battery-cage system to enriched cages, barn/aviary and free-range production systems. Government regulations have played an important role in setting some minimum welfare standards and the banning of battery cages in the UK and in some US states. However the commodification and market segmentation of higher welfare standards has also seen the growth in production and demand of cage-free and free-range eggs in all three countries. This paper maps and compares the developments in government regulation and market segmentation of layer-hen welfare in the UK, Australia and the USA. The role of labelling and certification in facilitating commodification and market segmentation will be examined, including the public controversies and legal conflicts over egg labelling. The key state, market and civil society actors in each country will also be identified, and their role in driving or resisting higher standards examined, including the increasingly influential role of animal welfare organizations and food corporations.  相似文献   
352.
A study to characterize primary particulate matter (PM2.5 and PM10) from the French vehicular fleet was conducted during winter 2008, in a tunnel in Marseille, France. The carbonaceous fraction represents 70% of the aerosol mass and elemental carbon fraction (EC) represent 60% of the carbonaceous fraction. The organic carbon OC was characterized in term of its water soluble fraction, functionalization rate and HULIS content. Seventy trace organic compounds including alkanes, polycyclic aromatic hydrocarbons (PAH), petroleum biomarkers and carboxylic acids were also quantified, in order to determine an organic emission profile for chemical mass balance modeling studies. Such source profiles were still missing in Europe and particularly in France. The profile obtained in this study is consistent with profiles determined in tunnel or dynamometer studies performed in other countries during the last ten years. These results suggest that organic compounds profiles from vehicular exhaust emissions are not significantly influenced by the geographic area and are thus suitable for use in aerosol source apportionment modeling applied across extensive regions. The chemical profile determined here is very similar to those obtained for diesel emissions with high concentrations of EC relative to OC (EC/OC = 1.8) and low concentrations of the higher molecular weight PAH. These results are consistent with the high proportion of diesel vehicles in the French fleet (49%).  相似文献   
353.
The use of the gasoline additive methyl tert-butyl ether (MTBE) has caused serious concern about groundwater and surface water contamination. The behavior of MTBE in the two most relevant compartments, surface water and air in a generic environment and in a simulated German environment is investigated using the equilibrium criterion (EQC) model. Due to lack of literature data, the half-life time of MTBE in river water is estimated to about 80-120 d (105 d) at 18 degrees C and roughly 1.5 a (year)(533 d) at 4 degrees C from a batch experiment. The EQC model considers four compartments, air, surface water, soil and sediment in an environment of typically 100,000 km2 with about 10% of the area covered with water. The user can progress through the tiered sequence of Level I to III with increasing complexity which reveals more information about the the fate of the considered chemical. The equilibrium mass distribution of MTBE calculated with the Level I model shows that 87% partitions into air and 13% into surface water at 10 degrees C. The results of the Level II calculations indicate that 50% of MTBE in the air is transported from the system and 38% in the air is degraded at 10 degrees C. The resulting total persistence time of 3 d for MTBE in the generic environment of the Level II model can be compared to the calculated value for chlorobenzene. The MTBE input into water is significantly more sensitive to the 'mode of entry' than input into air. The MTBE concentration in surface water is almost exclusively the result of direct emission into water, whereas the atmosphere can additionally be loaded by volatilization from water. The total aquatic MTBE emission in Germany and the average MTBE concentration in German surface waters were roughly estimated to 20-80 t a(-1) (tons per year)(50 t a(-1)) and 50 ng L(-1), respectively. Surface water concentrations calculated with the underlying assumptions of the model can neither be explained by exposure through waste water and industrial effluents nor with an estimated loss of industrially used MTBE in Germany. For the year-round scenario at 10 degrees C, MTBE concentrations of 19 ng L(-1) (surface water) and 167 ng m(-3) (air) result. However, it remains unclear whether the assumptions of the model, the lack of analyses from industrial effluents or both are responsible for the difference. Additional aquatic emission sources could result from gasoline transport on and storage near rivers. The comparison of winter and summer scenarios shows that in summer, atmospheric (25%) and aqueous (50%) concentrations are lower than in winter due to higher degradation rates.  相似文献   
354.
This study focussed on a comparison of the extractability of mercury in soils with two different contamination sources (a chlor-alkali plant and mining activities) and on the evaluation of the influence of specific soil properties on the behaviour of the contaminant. The method applied here did not target the identification of individual species, but instead provided information concerning the mobility of mercury species in soil. Mercury fractions were classified as mobile, semi-mobile and non-mobile. The fractionation study revealed that in all samples mercury was mainly present in the semi-mobile phase (between 63% and 97%). The highest mercury mobility (2.7 mg kg(-1)) was found in soils from the industrial area. Mining soils exhibited higher percentage of non-mobile mercury, up to 35%, due to their elevated sulfur content. Results of factor analysis indicate that the presence of mercury in the mobile phase could be related to manganese and aluminium soil contents. A positive relation between mercury in the semi-mobile fraction and the aluminium content was also observed. By contrary, organic matter and sulfur contents contributed to mercury retention in the soil matrix reducing the mobility of the metal. Despite known limitations of sequential extraction procedures, the methodology applied in this study for the fractionation of mercury in contaminated soil samples provided relevant information on mercury's relative mobility.  相似文献   
355.
Macroalgal invasions in coastal areas have been a growing concern during the past decade. The present study aimed to assess the role of hull fouling on recreational yachts as a vector for macroalgal introductions. Questionnaire and hull surveys were carried out in marinas in France and Spain. The questionnaires revealed that the majority of yacht owners are aware of seaweed introductions, usually undertake short range journeys, dry dock their boat at least once a year, and use antifouling paints. The hull survey showed that many in-service yachts were completely free of macroalgae. When present, fouling assemblages consisted mainly of one to two macroalgal species. The most commonly found species was the tolerant green seaweed Ulva flexuosa. Most of the other species found are also cosmopolitan and opportunistic. A few nonnative and potentially invasive Ceramiales (Rhodophyta) were found occasionally on in-service yachts. On the basis of the information gathered during interviews of yacht owners in the surveyed area, these occurrences are likely to be uncommon. However they can pose a significant risk of primary or secondary introductions of alien macroalgal species, especially in the light of the increase in yachting activities. With large numbers of recreational yachts and relatively rare occurrences of nonnative species on hulls, comprehensive screening programs do not seem justified or practical. The risks of transferring nonnative species may, however, be minimized by encouraging the behaviors that prevent fouling on hulls and by taking action against neglected boats before they can act as vectors.  相似文献   
356.
The loss of contaminated wastewater into the environment by leakage or other means is a serious problem. This problem is essentially the same as true of the loss of chemical reagents from a chemical production or purification process. The present article shows how the joint estimation method, an outlier detection method for time series analysis, can be used by a facility manager to deal with these problems.  相似文献   
357.
The abundance of plastics in stomachs of northern fulmars from the North Sea is used in the OSPAR Ecological Quality Objective (EcoQO) for marine litter. The preliminary EcoQO defines acceptable ecological quality as the situation where no more than 10% of fulmars exceed a critical level of 0.1 g of plastic in the stomach. During 2003-2007, 95% of 1295 fulmars sampled in the North Sea had plastic in the stomach (on average 35 pieces weighing 0.31 g) and the critical level of 0.1 g of plastic was exceeded by 58% of birds, with regional variations ranging from 48 to 78%. Long term data for the Netherlands since the 1980s show a decrease of industrial, but an increase of user plastics, with shipping and fisheries as the main sources. The EcoQO is now also used as an indicator for Good Environmental Status in the European Marine Strategy Framework Directive.  相似文献   
358.
Engineered nano-sized Cu oxide particles are extensively used in diverse applications. Because aquatic environments are the ultimate “sink” for all contaminants, it is expected that nanoparticles (NP) will follow the same fate. In this study, two marine invertebrates Scrobicularia plana and Hediste diversicolor were chosen as ecotoxicological models. The aim was to evaluate behavioural (burrowing kinetics, feeding rate) and biochemical (biomarkers) responses of S. plana and H. diversicolor exposed in the laboratory to Cu (10 μg L−1) added in natural seawater either in the form of engineered nanoparticles (NPs) of CuO or as dissolved Cu in 2% HNO3. Exposure was characterized by considering (i) the physico-chemical fate of NP (ii) the fraction of labile Cu in experimental media and (iii) Cu bioaccumulation. Results showed high aggregation of CuO NPs in seawater and no additional bioavailable Cu concentrations. Behavioural impairments were observed in S. plana exposed to CuO NPs or soluble Cu whereas in H. diversicolor, only the exposure to soluble Cu led to a burrowing decrease. No obvious neurotoxicity effects were revealed since in both species, no changes in cholinesterasic activity occurred in response to both forms of Cu exposure. Biomarkers of oxidative-stress catalase and glutathione-S-transferase were enhanced in both species whereas superoxide dismutase was increased only in S. plana exposed to CuO NPs. Metallothionein-like protein was increased in bivalves exposed to both forms of Cu. Since, no detectable release of soluble Cu from CuO NPs occurred during the time of experiment, ecotoxicity effects seem to be related to CuO NPs themselves.  相似文献   
359.
The French Atlantic coast contains large highly productive intertidal mudflats that are colonised by juveniles of numerous flatfish species, including the common sole (Solea solea, L.). These ecosystems are also heavily exploited by the shellfish farming industry. Intensive bivalve culture is associated with substantial biodeposition (1–6 t-dw ha−1 day−1), which directly or indirectly contributes to increase exopolysaccharide (EPS) concentrations at the interface between water column and seabed. EPS are long-chain molecules organised into colloids, which influence rheological properties of water, particularly viscosity. Increased water viscosity had consequences for ventilatory activity of juvenile flatfish, whereby the minimal pressure required to ventilate the medium increases directly with EPS concentration. Moreover, the critical EPS concentration ([EPS]crit) at which water was no longer able to flow through the branchial basket ranged from almost nil to over 30 mg l−1, depending on species and size. [EPS]crit was lower in small individuals and individuals from species with high metabolic rates (turbot and plaice). These differences may depend upon gill and bucco-branchial cavity morphometrics. The ventilatory workload of sole increased with viscosity to a maximum at 2 mg EPS l−1. Viscosity might, therefore, be a limiting factor for flatfish post larvae, which colonise the intertidal mudflats, depending upon their size and species. EPS concentrations in the field can reach 15 mg l−1. A selective effect is conceivable but remains to be estimated in the field.  相似文献   
360.
Scleractinian symbiotic corals living in the Ligurian Sea (NW Mediterranean Sea) have experienced warm summers during the last decade, with temperatures rapidly increasing, within a few days, to 3–4°C above the mean value of 24°C. The effect of elevated temperatures on the photosynthetic efficiency of zooxanthellae in symbiosis with temperate corals has not been well investigated. In this study, the corals, Cladocora caespitosa and Oculina patagonica were collected in the Ligurian Sea (44°N, 9°E), maintained during 2 weeks at the mean summer temperature of 24°C and then exposed during 48 h to temperatures of 24 (control), 27, 29 and 32°C. Chlorophyll (chl) fluorescence parameters [F v/F m, electron transport rate (ETR), non-photochemical quenching (NPQ)] were measured using pulse amplitude modulated (PAM) fluorimetry before, during the thermal increase, and after 1 and 7 days of recovery (corals maintained at 24°C). Zooxanthellae showed a broad tolerance to temperature increase, since their density remained unchanged and there was no significant reduction in their maximum quantum yield (F v/F m) or ETR up to 29°C. This temperature corresponded to a 5°C increase compared to the mean summer temperature (24°C) in the Ligurian Sea. At 32°C, there was a significant decrease in chl contents for both corals. This decrease was due to a reduction in the chl/zooxanthellae content. For C. caespitosa, there was also a decrease in ETRmax, not associated with a change in F v/F m or in the non-photochemical quenching (NPQ); for O. patagonica, both ETRmax and F v/F m significantly decreased, and NPQmax showed a significant increase. Damages to the photosystem II appeared to be reversible in both corals, since F v/F m values returned to normal after 1 day at 24°C. Zooxanthellae in symbiosis with the Mediterranean corals investigated can therefore be considered as resistant to short-term increases in temperature, even well above the maximum temperatures experienced by these corals in summer.  相似文献   
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