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871.
An increasing number of studies indicate that marine mammals and some seabirds are exposed to organotins. However, results from northern and Arctic areas are few. Here results from analysis of tributyltin (TBT), dibutyltin (DBT), monobutyltin (MBT), triphenyltin (TPhT), diphenyltin (DPhT) and monophenyltin (MPhT) in harbour porpoise (Phocoena phocoena), common seal (Phoca vitulina), ringed seal (Phoca hispida) and glaucous gull (Larus hyperboreus) from Norwegian territory are presented. Relatively high concentrations of DBT, TBT and MBT were observed in muscle, kidney and liver from harbour porpoises caught in northern Norway in 1988, just before restrictions on the use of tributyltin (TBT)(mainly on small boats) were introduced in several European countries. The concentrations in harbour porpoise muscle tissue were reduced significantly 11 years later, possibly as a result of the introduced restrictions. Considerably lower concentrations of butyltins were observed in the seals compared to porpoises. The lowest levels of organotins were found in ringed seals from Spitsbergen, where only traces of dibutyltin (DBT) and monobutyltin (MBT) were observed. Traces of DBT and MBT were also found in some individual glaucous gulls from Bear Island. The sum of the degradation products MBT and DBT in liver samples from all analysed species were generally higher than TBT itself. Triphenyltin (TPhT) was observed in all porpoise samples and in livers of common seals. Also the sum of the degradation products MPhT and DPhT in liver samples from porpoise and common seals were higher than TPhT. No traces of phenyltins were found in ringed seals from Spitsbergen or in glaucous gulls from Bear Island. The limited data available indicate low to moderate exposure to organotins in northern areas (Spitsbergen and Bear Island). Marine mammals are however more exposed further south along the Norwegian Coast.  相似文献   
872.
Two test methods are presented to assess the cytotoxicity of chemicals. On one hand the protozoonTetrahymena pyriformis and on the other the bacteriumPseudomonas aeruginosa is cultured in defined media containing the test chemicals. Test parameter is the quantity of living cells surviving exposure. The conversion of the tetrazolium salt MTT into formazan is equivalent to cell viability. A mixture of detergent and isopropanol is used to dissolve the blue formazan which is not soluble in water, prior to photometric measurement. For cetyltrimethylammonium bromide, benzyldimethyldodecylammonium chloride, dodecylbenzenesulfonic acid sodium salt, potassium dichromate, 4-toluenesulfonic acid sodium salt, and 4-nitrophenol the EC50-values (mol/l) in theTetrahymena pyriformis- (Pseudomonas aeruginosa) test system were: 10?5,81 (10?5,08); 10?4,68) (10?3,80; 10?4,50 (10?4,14); 10?3,97 (10?5,11); 10?2,71 (10?2,50) and 10?4,00 (10?3,64). — With the assays described here it is possible to measure a large number of samples by quick and simple means.  相似文献   
873.
Citizens' juries (CJs) are recommended as one approach that might be used to encourage the active involvement of interested parties in the implementation of the EU Water Framework Directive (WFD). In this light the paper critically reviews the citizens' jury method in the context of water resource management. It examines three strategic challenges of representation, accountability and the role of experts, and issues of scale related to geography, institutions and time. Innovative adaptations of the CJ approach and other deliberative methods are explored as means to address these challenges. The review concludes by arguing that CJs will only be suitable for use in implementation of the WFD if such adaptations are further developed and used to tailor the CJ approach to the particular needs of water resource management in different circumstances.  相似文献   
874.
We developed logistic regression models from data on biotic and abiotic variables for 172 sites on Banks Peninsula, New Zealand, to predict the probability of occurrence of two diadromous fish, banded kokopu (Galaxias fasciatus) and koaro (G. brevipinnis). Banded kokopu occurrence was positively associated with small streams and low-intensity land uses (e.g., sheep grazing or forested), whereas intensive land uses (e.g., mixed sheep and cattle farming) and lack of riparian forest cover impacted negatively on occurrence at sampled sites. Also, if forests were positioned predominantly in lowland areas, banded kokopu occurrence declined with increasing distance to stream mouth. Koaro occurrence was positively influenced by catchment forest cover, high stream altitudes, and areas of no farming activity or mixed land uses. Intensive land uses, distance to stream mouth, and presence of banded kokopu negatively influenced koaro occupancy of stream reaches. Banded kokopu and koaro presence was predicted in 86.0% and 83.7% agreement, respectively, with field observations. We used the models to quantify the amount of stream reaches that would be of good, moderate, and poor quality, based on the probability of occurrences of the fish being greater than 0.75, between 0.75 and 0.5, or less than 0.5, respectively. Hindcasting using historical data on vegetation cover undertaken for one catchment, Pigeon Bay, showed they would have occupied most of the waterway before anthropogenic modification. We also modeled potential future scenarios to project potential fish distribution.  相似文献   
875.
联合国秘书长科菲·安南: “让我鼓励所有的人都加入国际劳工组织,致力于促进职业安全与健康。这不仅是一项合理的经济决策,也是一项基本的人权。”  相似文献   
876.
Short-term impacts of aerial application of Bacillus thuringiensis israelensis (Bti) on Culicidae and Chironomidae were investigated over several years in temporary waters of the Dyje and Morava floodplains in Eastern Austria. The sampling followed a Before-After-Control-Impact (BACI) approach with sampling dates immediately before and shortly after the application and was repeated for 3 years. To test for effects of the Bti treatment on the two Diptera families, linear mixed-effects models were used. Data analysis included the factors Before-After and Control-Impact as fixed effects, while general temporal and spatial variables were random effects. One hundred sixteen taxa of chironomids were identified. Abundance varied between 2 and 1125 larvae per m2, while culicid densities reached values of several 100 ind. per liter. Total culicid abundance significantly decreased after the Bti treatment, whereas no significant effects were found on the abundance of total chironomids and dominant chironomid subfamilies, tribes, and genera, on relative proportions of chironomid feeding guilds, diversity, and species composition. Further studies from this area are needed to extend the investigation over a period of several weeks in order to reveal possible delayed effects of the larvicide application.  相似文献   
877.
Wet deposition of nitrogen, as NH(4)(+), NO(3)(-), and organic N, contributes up to 50% of the total externally supplied or 'new' N flux to the Neuse River Estuary (North Carolina). Excessive nitrogen (N) loading to N-sensitive waters such as the Neuse River Estuary has been linked to changes in microbial and algal community composition and function (harmful algal blooms), hypoxia/anoxia, and fish kills. In a 4-year study from July 1996 to July 2000, the weekly wet deposition of NH(4)(+), NO(3)(-), and dissolved organic N was calculated, based on concentration and precipitation measurements, at 11 sites on a northwest-southeast transect in the watershed. Data from this period indicate that the annual mean total wet atmospherically deposited (AD)-N flux was 11 kg ha(-1) year(-1). Deposition was fairly evenly distributed between nitrate, ammonium, and organics (32%, 32%, and 36%, respectively). Seasonally, the summer (June-August) months contained the highest weekly wet total N deposition; this trend was not driven by precipitation amount. Estimates of watershed N retention and in-stream riverine processing revealed that the AD-N flux contributed an estimated 20% (range of 15-51%) of the total 'new' N flux to the estuary, with direct deposition of N to the estuary surface accounting for 6% of the total 'new' N flux. This study did not measure the dry depositional flux, which may double the contribution of AD-N to the estuary. The AD-N is an important source of 'new' N to the Neuse River Estuary as well as other estuarine and coastal ecosystems downwind of major emission sources. As such, AD-N should be included in effective nutrient mitigation and management efforts for these N-sensitive waters.  相似文献   
878.
A demonstration project in Oregon examined the feasibility of combining Federal environmental monitoring surveys. An integrated approach should remove duplication of effort and reduce the possibility of providing apparently conflicting information to policy makers and the public. Data collection teams made photo interpretation measurements and on-site soil/vegetation/animal observations at locations that were selected from the Forest Inventory and Analysis (FIA), National Forest System (NFS) Region 6, and National Resource Inventory (NRI) surveys in a six-county area in Northern Oregon. The project demonstrated the feasibility of conducting a combined FIA/NFS/NRI survey and suggests an approach that will preserve the utility of the critical historical information from these surveys. We suggest a framework for estimating the extent of forest and range land that explains FIA/NRI differences and provides a common basis for both surveys. We suggest indicator and protocol criteria that will allow consistent national and regional estimates over all vegetation types, and stress the importance of including measurement repeatability in the design of the combined survey.  相似文献   
879.
Perfluorooctane sulfonic acid (PFOS) is a persistent and ubiquitous environmental contaminant that has been detected in organisms worldwide. Here, we evaluate whether long-term (1 and 4 months) exposure to PFOS contamination affects the behavioural performance of freshwater larvae of the damselfly Enallagma cyathigerum (Insecta: Odonata). Our results show reduced behavioural performance with increasing PFOS concentration. In 1 month exposed larvae, no observed effect concentrations (NOECs) were 100 μg/L for general activity. In 4 months exposed larvae, NOECs were 10 μg/L, for each behavioural trait, except swimming acceleration of male larvae where the NOEC was 100 μg/L. When faced with PFOS concentrations above the NOEC, E. cyathigerum larvae were less active, less capable to escape a simulated predator attack and less efficient in foraging. Together, our results show that damselfly larvae suffer reduced survival-related behavioural performance.  相似文献   
880.
Dioxin-like activity was measured in the serum of 1425 Flemish men and women via the CALUX assay. The adults, aged between 50 and 65 years, participated in a large biomonitoring program, executed by the Flemish Center of Expertise for Environment and Health between 2002 and 2006. Within the context of this biomonitoring program also dietary intake of dioxin-like contaminants was assessed through a food frequency questionnaire. The relation between the estimated dietary intake and the dioxin-like activity in serum was evaluated using multivariate analyses: a logistic model was performed on the total population, while a linear regression analysis was done on the subsample with quantifiable dioxin activity levels in serum. Region, gender, age, BMI, smoking status, as well as dietary habits were entered in the model, with dioxin level as an outcome estimate. Both the logistic and linear model confirmed the contribution of dietary intake to the dioxin activity measured in serum. Also BMI and region were found to be associated with dioxin activity levels.  相似文献   
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