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101.
The results of a study using epiphytic lichens (Parmelia caperata) as sentinels for heavy metal deposition at six selected forest ecosystems of central Italy are reported. The woods investigated are characterized by holm oak (Quercus ilex), turkey oak (Quercus cerris) and beech (Fagus sylvatica) and represent the typical forest ecosystems of central Italy at low, medium and high elevations, respectively. The results showed that levels of heavy metals in lichens were relatively low and consequently no risk of heavy metal air pollution is expected for the six forest ecosystems investigated. However, for two of them there are indications of a potential risk: the beech forest of Vallombrosa showed signs of contamination by Pb as a consequence of vehicle traffic due to the rather high touristic pressure in the area, and the holm oak forest of Cala Violina showed transboundary pollution by Mn, Cr and Ni originating from the steel industry in Piombino. Epiphytic lichens proved to be very effective as an early warning system to detect signs of a changing environment at forest ecosystems.  相似文献   
102.
Amniotic fluid samples received for routine prenatal diagnosis of open neural tube defects were used for a study to compare amniotic fluid acetylcholinesterase (AChE) determination using a monoclonal antibody (4F19) enzyme antigen immunoassay and amniotic fluid alpha-fetoprotein (AFP) measurement as diagnostic tests for open neural tube defects. The study was based on 9964 women with singleton pregnancies and known outcome (including 6 with anencephaly and 18 with open spina bifida) having an amniocentesis at 14–23 weeks of gestation. The AChE immunoassay yielded detection rates for anencephaly of 100 per cent (95 per cent confidence interval (CI) 54·07–100 per cent), for open spina bifida of 100 per cent (95 per cent CI 81·47–100 per cent), for anterior abdominal wall defects of 20 per cent (95 per cent CI 0-51-71-64 per cent), and a false-positive rate of 0·22 percent (95 per cent CI 0·14–0·34 per cent) excluding anencephaly, open spina bifida, and anterior abdominal wall defects. For similar detection rates the false-positive rate of the AFP test was significantly higher, 0·74 per cent (95 per cent CI 0·58–0·94 per cent). On the basis of these findings, it is recommended that the technically simple AChE immunoassay should be used on all samples; the AFP test should only be used on the 0·5 per cent of the samples with concentrations of AChE activity ⩾ 8·5 nkat/1 for clear samples and blood-stained samples becoming clear after centrifugation, and ⩾ 25·0 nkat/1 for blood-stained samples that are discoloured after centrifugation; an AFP cut-off level of 2·0 MOM is recommended for this policy. Thereby, the detection rates for anencephaly, open spina bifida, and anterior abdominal wall defects would be 100, 100, and 20 per cent, respectively (95 per cent CIs 54·07–100, 81·47–100, and 0·51–71·64 per cent, respectively), and the false-positive rate would be 0·08 per cent (95 per cent CI 0·03–0·16 per cent) (excluding anencephaly, open spina bifida, and anterior abdominal wall defects).  相似文献   
103.
104.
The Marano and Grado Lagoon is well known for being contaminated by mercury(Hg) from the Idrija mine(Slovenia) and the decommissioned chlor-alkali plant of Torviscosa(Italy).Experimental activities were conducted in a local fish farm to understand Hg cycling at the sediment–water interface. Both diffusive and benthic fluxes were estimated in terms of chemical and physical features. Mercury concentration in sediments(up to 6.81 μg/g)showed a slight variability with depth, whereas the highest methylmercury(MeHg) values(up to 10 ng/g) were detected in the first centimetres. MeHg seems to be produced and stored in the 2–3 cm below the sediment–water interface, where sulphate reducing bacteria activity occurs and hypoxic–anoxic conditions become persistent for days. DMeHg in porewaters varied seasonally(from 0.1 and 17% of dissolved Hg(DHg)) with the highest concentrations in summer. DHg diffusive effluxes higher(up to 444 ng/m~2/day) than those reported in the open lagoon(~ 95 ng/m~2/day), whereas DMeHg showed influxes in the fish farm(up to-156 ng/m~2/day). The diurnal DHg and DMeHg benthic fluxes were found to be higher than the highest summer values previously reported for the natural lagoon environment. Bottom sediments, especially in anoxic conditions, seem to be a significant source of MeHg in the water column where it eventually accumulates. However, net fluxes considering the daily trend of DHg and DMeHg, indicated possible DMeHg degradation processes. Enhancing water dynamics in the fish farm could mitigate environmental conditions suitable for Hg methylation.  相似文献   
105.
Forced expiratory volume in 1 second (FEV1) was measured in 21 men exercising while exposed to four O3 concentrations (0.0,0.08,0.10, and 0.12 ppm). A lognormal multiple linear regression model was fitted to their mean FEV1 measurements to predict FEV1 percent decrease as a function of O3 concentration and exposure duration. The exercise level used was probably comparable to heavy manual labor. The longest O3, exposure studied was 6 h. Extrapolating cautiously to an 8-h workday of heavy manual labor, the model predicts that O3 concentrations of 0.08, 0.10, and 0.12 ppm would decrease FEV1 by 9,15, and 20 percent, respectively.  相似文献   
106.
At present, information on the reproductive physiology of Centroscymnus coelolepis, which is one of most important and widespread deep-sea shark species, is completely lacking. In this study, we investigated vitellogenesis, a key step in the reproduction biology of fishes. Specimens of C. coelolepis were collected at 2850 m depth in the Western Mediterranean Sea. The size of the collected sharks (range: 35.5–65.0 cm TL) was much lower than those typically reported for the Atlantic and Pacific Oceans. The marked distinctiveness of Mediterranean and Atlantic/Pacific populations was reflected by the achievement of sexual maturity at a smaller size in Mediterranean specimens. The examination of cytoplasmatic components of oocytes indicated that vitellogenin uptake in the ovary started when oocytes reached 14 mm in diameter. Only reproductive females displayed a significant relationship between plasmatic vitellogenin and gonadal development, suggesting that vitellogenesis in C. coelolepis is a discontinuous process. Oestradiol levels were tightly coupled with gonadal development, underlining the importance of this hormone in controlling vitellogenesis. All these findings suggest that vitellogenesis in this yolk-sac viviparous shark might occur with similar mechanisms of oviparous vertebrates.  相似文献   
107.
Public participation is a key element of Integrated Water Resources Management and, in the European Union (EU), is a major challenge in the implementation of the Water Framework Directive (WFD), which was adopted in December 2000. When new legislation enters into force it is essential to set a baseline against which to measure the progress towards the established goals at significant milestones of its implementation. This paper presents an assessment of the quality of stakeholder participation at the beginning of the WFD implementation in twenty countries belonging to or with close institutional relationships with the EU. The evaluation was completed by environmental non-governmental organizations and it shows that already in 2003 there were positive examples of stakeholder participation in several countries but that, in general, the WFD implementation will require significant efforts to improve on participatory practices throughout Europe.  相似文献   
108.
Regional Environmental Change - Spain is a highly decentralized country where water governance is a multi-level institutional endeavor requiring effective intergovernmental coordination—in...  相似文献   
109.
Recycling of paper and glass from household waste is an integrated part of waste management in Denmark, however, increased recycling is a legislative target. The questions are: how much more can the recycling rate be increased through improvements of collection schemes when organisational and technical limitations are respected, and what will the environmental and economic consequences be? This was investigated in a case study of a municipal waste management system. Five scenarios with alternative collection systems for recyclables (paper, glass, metal and plastic packaging) were assessed by means of a life cycle assessment and an assessment of the municipality’s costs. Kerbside collection would provide the highest recycling rate, 31% compared to 25% in the baseline scenario, but bring schemes with drop-off containers would also be a reasonable solution. Collection of recyclables at recycling centres was not recommendable because the recycling rate would decrease to 20%. In general, the results showed that enhancing recycling and avoiding incineration was recommendable because the environmental performance was improved in several impact categories. The municipal costs for collection and treatment of waste were reduced with increasing recycling, mainly because the high cost for incineration was avoided. However, solutions for mitigation of air pollution caused by increased collection and transport should be sought.  相似文献   
110.
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