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51.
Perfluorinated compounds (PFCs) are man-made chemicals for which endocrine disrupting properties and related possible side effects on human health have been reported, particularly in the case of an exposure during the early stages of development, (notably the perinatal period). Existing analytical methods dedicated to PFCs monitoring in food and/or human fluids are currently based on liquid chromatography coupled to tandem mass spectrometry, and were recently demonstrated to present some limitations in terms of sensitivity and/or specificity. An alternative strategy dedicated to the analysis of fourteen PFCs in human breast milk was proposed, based on an effective sample preparation followed by a liquid chromatography coupled to high resolution mass spectrometry measurement (LC-HRMS). This methodology confirmed the high interest for HRMS after negative ionization for such halogenated substances, and finally permitted to reach detection limits around the pg mL(-1) range with an outstanding signal specificity compared to LC-MS/MS. The proposed method was applied to a first set of 30 breast milk samples from French women. The main PFCs detected in all these samples were PFOS and PFOA with respective median values of 74 (range from 24 to 171) and 57 (range from 18 to 102) pg mL(-1), respectively. These exposure data appeared in the same range as other reported values for European countries.  相似文献   
52.
New concerns about biodiversity, ecosystem services and human health triggered several new regulations increasing the need for sound ecotoxicological risk assessment. The PEER network aims to share its view on the research issues that this challenges. PEER scientists call for an improved biologically relevant exposure assessment. They promote comprehensive effect assessment at several biological levels. Biological traits should be used for Environmental risk assessment (ERA) as promising tools to better understand relationships between structure and functioning of ecosystems. The use of modern high throughput methods could also enhance the amount of data for a better risk assessment. Improved models coping with multiple stressors or biological levels are necessary to answer for a more scientifically based risk assessment. Those methods must be embedded within life cycle analysis or economical models for efficient regulations. Joint research programmes involving humanities with ecological sciences should be developed for a sound risk management.  相似文献   
53.
Emissions from shipping traffic may impact severely upon air quality in port cities. In this study, the size and composition of freshly emitted individual ship exhaust particles has been investigated using an aerosol time-of-flight mass spectrometer (ATOFMS) co-located with a suite of real-time instrumentation at a site in the Port of Cork, Ireland. The collected spectra were clustered using the K-means algorithm and a unique ship exhaust class containing internally mixed elemental and organic carbon, sodium, calcium, iron, vanadium, nickel and sulfate was identified. Over twenty sharp emission events were observed for this particle type during the three week measurement period in August 2008. Coincident increases in mass concentrations of sulfate, elemental carbon and particles below 2.5 μm in diameter (PM2.5) were also observed during these events. Simultaneous scanning mobility particle sizer (SMPS) measurements indicate that the vast majority of freshly emitted ship exhaust particles lie in the ultrafine mode (<100 nm diameter). A second particle class consisted of internally mixed organic carbon, elemental carbon, ammonium and sulfate, and is tentatively attributed to aged or regionally transported ship exhaust. The results suggest that ATOFMS single particle mass spectra, when used in conjunction with other air quality monitoring instrumentation, may be useful in determining the contribution of local shipping traffic to air quality in port cities.  相似文献   
54.
Lead concentrations and isotopic ratios were measured along two well-dated sediment cores from two distant lakes: Anterne (2100 m a.s.l.) and Le Bourget (270 m a.s.l.), submitted to low and high direct human impact and covering the last 250 and 600 years, respectively. The measurement of lead in old sediment samples (>3000 BP) permits, in using mixing-models, the determination of lead concentration, flux and isotopic composition of purely anthropogenic origin. We thus show that since ca. 1800 AD the regional increase in lead contamination was mostly driven by coal consumption ((206)Pb/(207)Pb approximately 1.17-1.19; (206)Pb/(204)Pb approximately 18.3-18.6), which peaks around 1915 AD. The increasing usage of leaded gasoline, introduced in the 1920s, was recorded in both lakes by increasing Pb concentrations and decreasing Pb isotope ratios. A peak around 1970 ((206)Pb/(207)Pb approximately 1.13-1.16; (206)Pb/(204)Pb approximately 17.6-18.0) corresponds to the worldwide recorded leaded gasoline maximum of consumption. The 1973 oil crisis is characterised by a drastic drop of lead fluxes in both lakes (from approximately 35 to <20 mg cm(-2) yr(-1)). In the late 1980s, environmental policies made the Lake Anterne flux drop to pre-1900 values (<10 mg cm(-2) yr(-1)) while Lake Le Bourget is always submitted to an important flux (approximately 25 mg cm(-2) yr(-1)). The good match of our distant records, together and with a previously established series in an ice core from Mont Blanc, provides confidence in the use of sediments as archives of lead contamination. The integration of the Mont Blanc ice core results from Rosman et al. with our data highlights, from 1990 onward, a decoupling in lead sources between the high elevation sites (Lake Anterne and Mont Blanc ice core), submitted to a mixture of long-distance and regional contamination and the low elevation site (Lake Le Bourget), where regional contamination is predominant.  相似文献   
55.
56.
Conservation decisions are typically made in complex, dynamic, and uncertain settings, where multiple actors raise diverse and potentially conflicting claims, champion different and sometimes contradictory values, and enjoy varying degrees of freedom and power to act and influence collective decisions. Therefore, effective conservation actions require conservation scientists and practitioners to take into account the complexity of multiactor settings. We devised a framework to help conservation biologists and practitioners in this task. Institutional economic theories, which are insufficiently cited in the conservation literature, contain useful insights for conservation. Among these theories, the economies of worth can significantly contribute to conservation because it can be used to classify the types of values peoples or groups refer to when they interact during the elaboration and implementation of conservation projects. Refining this approach, we designed a framework to help conservation professionals grasp the relevant differences among settings in which decisions related to conservation actions are to be made, so that they can adapt their approaches to the features of the settings they encounter. This framework distinguishes 6 types of agreements and disagreements that can occur between actors involved in a conservation project (harmony, stricto sensu arrangement, deliberated arrangement, unilateral and reciprocal compromise, and locked-in), depending on whether they disagree on values or on their applications and on whether they can converge toward common values by working together. We identified key questions that conservationists should answer to adapt their strategy to the disagreements they encounter and identified relevant participatory processes to complete the adaptation.  相似文献   
57.
Nest and territory defence are risky and potentially dangerous behaviours. If the resolution of life history trade-offs differs between individuals, the level of defence may also vary among individuals. Because melanin-based colour traits can be associated with life history strategies, differently coloured individuals may display different nest and territory defence strategies. We investigated this issue in the colour polymorphic tawny owl (Strix aluco) for which plumage varies from dark to light reddish melanic. Accordingly, we found that (1) our presence induced a greater response (flying around) from dark-coloured than light-coloured females and (2) dark reddish males suffered lower nest predation rates than light-coloured males. In experimentally enlarged broods, the probability that females reacted after we played back the hoot calls of a stranger male was higher if these females were lighter reddish; the opposite pattern was found in experimentally reduced broods with dark parents being more reactive than light parents. Finally, darker females alarmed more frequently when paired with a light than with a dark male, suggesting that partners adjust their behaviour to each other. We also tested whether colouration is used as a signal by conspecifics to adjust the level of their defensive behaviour. Accordingly, breeding females responded more vigorously to a dark than a light reddish stuffed tawny owl placed beside their nest. We conclude that melanin-based colouration is a signal of alternative nest and territory defence behaviour that depends on ecological factors.  相似文献   
58.
To determine the habitat and resource use of Dosidicus gigas in the Northern Humboldt Current System, we analysed carbon and nitrogen stable isotopes of 234 individuals collected during 2008–2010. Large variations in mantle stable isotope ratios were recorded, with values ranging from −19.1 to −15.1 ‰ (δ13C) and from 7.4 to 20.5 ‰ (δ15N). Most of the variation was explained by latitude, followed by distance to shelf break for carbon and by squid size for nitrogen. Latitudinal variations with increasing values from north to south were also found in zooplankton samples and were related to changes in isotope baseline values probably due to oxygen minimum zones that occur off Peru. This similar latitudinal trend in both zooplankton and D. gigas samples reveals that D. gigas is a relatively resident species at the scale of its isotopic turnover rate (i.e. a few weeks), even if this is not necessarily the case at the scale of its life. A small but significant size effect on δ13C values suggests that jumbo squid perform offshore–onshore ontogenic migration, with juveniles distributed offshore. For nitrogen, the high inter-individual variability observed with mantle length indicates that D. gigas can prey on a high variety of resources at any stage of their life cycle. This large-scale study off the coast of Peru provides further evidence that D. gigas have the capability to explore a wide range of habitats and resources at any stage of their life.  相似文献   
59.
This work focuses on assessing the impact of two types of waste pretreatment: addition of bottom ashes and aerobic pretreatment on both the onset and kinetics of methanogenesis and the evolution of different parameters in the leachate. It also studies the correlation between methane production and the different parameters measured in the leachate produced. A total of six 68-L pilots were thus used with fresh municipal solid waste (MSW) shredded to a 40-mm size. After 14months of landfilling, the control has produced less than 10NLkg(-1)DM, which corresponds to around 7% of its biochemical methane potential (BMP). Nevertheless, on one hand for aerobically pretreated waste, the lag phase before the onset of methanogenesis is significantly reduced to 0.9month compared to more than 1year for the control. In addition to that, on average 110NLkg(-1)DM (90% of the BMP) is produced within around 6.5months. On the other hand, the waste with added bottom ash shows a slight improvement of the lag phase over the control for one of the duplicate: 6.1months of lag phase. At this stage, on average of 26NLkg(-1)DM waste are detected (22% of the BMP) no final conclusion concerning the impact of bottom ashes could be made. The data obtained for the leachate parameters agrees with the observations on methane production. Statistical correlation study shows that the two components of the corrected PCA interpret 76% of the variability of the data: SUVA (specific UV absorbance at 254nm) and HPI(*) (% of hydrophilic compounds) are identified as interesting parameters for following up the biodegradation in landfill conditions.  相似文献   
60.
The little fire ant, Wasmannia auropunctata, constitutes one clonal supercolony throughout Israel, providing an opportunity to examine the effects of genotype versus environment on nestmate recognition. Intraspecific encounters among field-collected or among laboratory-maintained colonies were nonaggressive, but encounters between freshly collected and laboratory-maintained colonies were highly aggressive. Analyses of cuticular hydrocarbons revealed that freshly field-collected colonies had distinguishable profiles. Moreover, freshly collected colonies had profiles disparate from those of the same colonies after 4 months in the laboratory. These results indicate a strong interplay between genetic-based and environmentally based effects on the recognition cues. We propose that in the field the ants’ diet breadth is broad and consequently the incorporation of diet-borne substances is insufficient to mask the genetically determined cues. In the laboratory, however, the restricted diet promoted the incorporation of alien hydrocarbons at high levels, thus altering the genetically based cues to the point of alienation. These results shed a new light on the mechanisms by which environmental cues may affect label and/or template formation in ants. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
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