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4-Nonylphenol (4-NP) is of particular concern because of its ubiquity in aquatic environment and its endocrine-disrupting effects in aquatic organisms. On the basis of its octanol-water partition coefficient (104.6), it has a potential to bioaccumulate in aquatic food webs. However, there are no reported field studies on the trophodynamics of 4-NP and its precursor, nonylphenol polyethoxylate (NPEOs) surfactants, in aquatic food webs. This study reports the trophodynamics of 4-NP and NPEOs (4 < s < 16) in a marine aquatic food web from Bohai Bay, North China. 4-NP and NPEOs (4 < s < 16) were determined in 14 marine species including plankton, benthic invertebrates, fish, and marine birds. This paper provides the first report on the occurrence of NPEOs with s > 5 in marine biota. Co-analysis of DDTs in all samples allowed a direct comparison of the bioaccumulation behavior of DDTs with that of NP and NPEOs. The lipid equivalent concentration of DDE and 2,2-bis(chlorophenyl)-1-chloroethylene (DDMU) increased with increasing trophic level, and the trophic level was determined by stable isotope ratios. The trophic magnification factors (TMFs) of DDE and DDMU were 3.26 and 3.7, respectively. Lipid equivalent concentrations of 4-NP and of all NPEOs did not exhibit a statistically significant correlation with trophic levels in the food web, and the TMF of NP was 0.83, which was similar to those of all NPEOs (0.45-1.22). These results show that in the studied aquatic food web, there was no trophic magnification for 4-NP and NPEOs, whereas DDE and DDMU biomagnified.  相似文献   

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The development of methods to extract information from landscape analysis to refine risk assessment is becoming increasingly important. This paper presents results from a pesticide surface water exposure assessment at the watershed scale, based on a combination of edge of field studies, large-scale monitoring studies, and modeling activities with GIS-based landscape analysis methodologies covering an area of approximately 3200 ha surrounding the Simeto River in Sicily (Italy). The dynamic behavior of the pesticide chlorpyrifos-methyl was modeled in two different steps: calculation of the fraction of the application rate that is deposited beyond the field edge and simulation of the fate and persistence of the pesticide in the aquatic environment. Drift loads showed high spatial variability. Considering spray drift deposition as a fraction of the pesticide application rate, 60% of the results were < or = 0.02 (equal to 0.04 mg/m2). Only 8.5% of the results were above 0.5. The highly variability of the landscape factors was reflected in the results. More than 60% of the predicted pesticide concentrations were less than the limit of quantification (0.05 microg/L), affecting about 75% of the total length of the river tract analyzed. Predicted pesticide concentrations were higher than 0.1 microg/L in 23% of cases, but this corresponded to an insignificant portion of the river (1.2% of the total length). These results suggest that management options, such as increased no-spray zones, could provide further protection for surface water. These could be modeled to illustrate their overall impact. As an alternative, the introduction of a 20-m no-spray zone clearly reduced potential exposure, and 92% of the water body was protected. Estimated data are in agreement with data collected during a field monitoring study.  相似文献   

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This study investigated the effect that the taste of certain metals has on the perception of food. Four spoons plated with different metals (gold, copper, zinc, and stainless steel) were used to taste cream samples having different tastes: sweet, sour, bitter, salty, and plain. The results revealed that the zinc and copper spoons, in addition to transferring a somewhat metallic and bitter taste, enhanced to a greater or lesser extent, each cream’s dominant taste. Contrary to our expectations, the metallic taste of the copper and zinc spoons did not seem to affect the pleasantness of the samples significantly. These findings reveal that the effect that the metals from which cutlery can be made have on food perception differs from that found when the metal salts are added to the composition of the food itself.  相似文献   

6.
Household food consumption surveys indicate that the diet in Kenya is ill balanced and that many families cannot afford nutrient-rich foods such as meat and fruits. In this regard, rural populations-the majority of the Kenyan population-are much worse off than urban populations. Agriculture, the most important sector in the Kenyan economy, contributes 27% of the gross domestic product and generates 65% of the country's export earnings. Food-enhancing biotechnologies thus could increase national food yields and fill nutrition gaps by contributing to household and national food security and poverty reduction in Kenya. To overcome barriers to adopting biotechnology to improve food crops in Kenya and elsewhere in Africa, policy makers must create a receptive environment for, increase public understanding of, and stimulate investment in the new technology.  相似文献   

7.
Hu J  Zhen H  Wan Y  Gao J  An W  An L  Jin F  Jin X 《Environmental science & technology》2006,40(10):3142-3147
Organotins, especially tributyltin (TBT) and triphenyltin (TPT), are of particular concern due to their ubiquity in the aquatic environment and theirtoxicityto aquatic organisms. This study reports field studies on trophic magnification factors (TMF) of TBT and TPT in a marine food web. TBT, TPT, and their metabolites in plankton, five benthic invertebrate species, and six fish species collected from Bohai Bay, North China were determined, and it was found that the concentrations of TPT in marine fish were unexpectedly higherthan those of TBT. A positive relationship was found between trophic levels and concentrations of TPT, indicating trophic magnification of TPT in this food web. The TMF of TPT was calculated to be 3.70. On the other hand, concentrations of TBT, dibutyltin (DBT) and monobutyltin (MBT) did not exhibit statistically significant trends with trophic levels, and the TMF of TBT was 0.59. Analysis of organotins in the water and surface sediment from Bohai Bay revealed low inputs of TPT to the environment, which indicated that the high concentrations of TPT found in fish from Bohai Bay were due to the food web magnification of TPT.  相似文献   

8.
Saltworks have emerged as important alternative/complementary feeding habitats for avifauna. However, the consequences of such habitat shifts in terms of changes in exposure to contaminants are poorly understood. We evaluated the exposure of the waterbird community breeding at the saltworks of Thyna (Tunisia) to total Hg (THg) and Se according to their differential use of saltworks dietary resources, as revealed by δ13C and δ1?N values in their eggs (included species [n] -sorted according to increasing reliance on saltworks resources: Yellow-legged Gull Larus michahellis [12], Common Tern Sterna hirundo [12], Slender-billed Gull Larus genei [15], Little Egret Egretta garzetta [20], and Pied Avocet Recurvirostra avosetta [22]). Concentrations of THg and Se were under the threshold points for deleterious effects. Egg THg concentrations significantly decreased as the dietary contribution of saltworks resources increased (mean: 3.23, 1.66, 0.76, 0.4, and 0.27 μg/g dw, respectively). Conversely, egg Se concentrations did not vary according to foraging habitats (2.49, 2.96, 2.61, 3.27, and 1.5 μg/g dw, respectively). Tracing waterbird exposure to THg and Se at saltworks was feasible through the use stable isotopic assays of eggs. Birds using saltworks are not exposed to higher concentrations of THg and Se than in adjacent marine habitats.  相似文献   

9.
Recreational marine beaches in California are posted as unfit for swimming when the concentration of fecal indicator bacteria (FIB) exceeds any of seven concentration standards. Finding and mitigating sources of shoreline FIB is complicated by the many potential human and nonhuman sources of these organisms and the complex fate and transport processes that control their concentrations. In this study, a three-tiered approach is used to identify human and nonhuman sources of FIB in Avalon Bay, a popular resort community on Catalina Island in southern California. The first and second tiers utilize standard FIB tests to spatially isolate the FIB signal, to characterize the variability of FIB over a range of temporal scales, and to measure FIB concentrations in potential sources of these organisms. In the third tier, water samples from FIB "hot spots" and sources are tested for human-specific bacteria Bacteroides/Prevotella and enterovirus to determine whether the FIB are from human sewage or from nonhuman sources such as bird feces. FIB in Avalon Bay appear to be from multiple, primarily land-based, sources including bird droppings, contaminated subsurface water, leaking drains, and runoff from street wash-down actvities. Multiple shoreline samples and two subsurface water samples tested positive for human-specific bacteria and enterovirus, suggesting that at least a portion of the FIB contamination is from human sewage.  相似文献   

10.
The following is a personal account of a school-based research co-ordinator, tracing the development of the Norwich Consortium in one school. It also draws on written evidence provided by other teachers involved in the project.  相似文献   

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在很多纺纱厂,只要关注一下它们的生产标准、废料控制、劳动力及运转状况,不难发现在很多环节可以通过较小的投入来降低输入成本。  相似文献   

12.
Using the Niagara Peninsula Appellation as the case study, qualitative research was employed through the use of interviews conducted with wineries and industry associations, in an attempt to answer two specific questions: (1) how does the wine industry and wine tourism aid in the development of Niagara’s rural area using the integrated rural tourism (IRT) concept, and (2) how can IRT aid in rural development through direct, experiential, conservation, development, and synergistic benefits. It is apparent that the seven components of IRT provide a reasonable framework to analyse the ability of IRT to realize benefits, although that the addition of marketing and future needs/desires as components improve its explanatory power. Using the modified IRT framework, this research found that wine tourism has derived direct, experiential, conservation, and synergistic benefits, with work still to be undertaken in order to improve upon tourism’s positive impacts in Niagara and peripherally rural areas more generally in the areas of community engagement and improved industry synergy.  相似文献   

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Yano E 《Tobacco control》2005,14(4):227-33; discussion 233-5
Objectives: To provide a participant''s account of the development of a paper commissioned by the tobacco industry examining the reliability of self reported smoking status; to redress the distorted report of this Japanese spousal smoking study which evaluated the reliability and validity of self reported smoking status, and estimated confounding by diet and lifestyle factors. Design: Repeated interviews on smoking status and its verification by environmental and biological markers for environmental tobacco smoke (ETS) exposure. Setting: Urban wives in Osaka City and Sizuoka City, Japan Participants: Semi-random sampling of 200 wives in each city. From the Osaka subjects, 100 non-smoking wives were selected for the validity study. Main outcome measures: Kappa coefficient for reliability of self reported smoking status. Correlation coefficients between environmental nicotine concentration, cotinine in saliva and urine, and self reported smoking status. Results: The κ coefficient for the repeated interview was high suggesting sufficient reliability of the response. The proportion of self reported current smokers misclassified as non-smokers was equivalent to the misclassified self reported non-smokers. Ambient concentration of nicotine and personal exposure to nicotine correlated with each other and also with salivary cotinine and self reported ETS exposure but not with urinary cotinine/creatinine ratio (CCR). There was no major difference in diet and lifestyle related to husband''s smoking status. Conclusion: Self reported smoking status by Japanese wives shows high reliability. It also shows high validity when verified by both nicotine exposure and salivary cotinine, but not by CCR. A previous report questioning the credibility of self reported smoking status, based on questionable CCR, could thus be of dubious validity. In addition, possible dietary and lifestyle confounding factors associated with smoking husbands were not demonstrable, a finding not reported previously. Using all the data from this project changes the conclusion of the previous published report. In addition to the distortion of scientific findings by a tobacco industry affiliated researcher, anti-smoking campaigners made attempts to intimidate and suppress scientific activities. These distortions of science should be counteracted.  相似文献   

16.
The owner of a 500-cow Holstein herd requested economic assessment of his embryo transfer program. Actual net economic benefit was determined from marginal cost and present value of lifetime milk predicted from first lactations of 24 cows produced by embryo transfer compared with those of their 51 contemporaries sired by artificial insemination. Actual average pregnancy rate was 60% by embryo transfer or AI. An average of 5.5 transferable embryos was obtained per collection, which produced 1.37 cows in first lactation. Additional milk from embryo transfer cows was from more intensive selection of sires. Additional milk from the donor cows did not differ from zero. Actual marginal cost of a replacement by embryo transfer was +215, but it would have been +200 with same +25/unit semen price as contemporaries. If donors had been from the elite 5% for transmitting ability in milk, present value of gain in milk (5% real interest rate) ignoring additional feed costs would have been less than the cost of embryo transfer. For management and costs similar to this case, embryo transfer is not economically justified for producers earning income primarily from the sale of milk.  相似文献   

17.
A case history of the manufacture and use of whey protein isolate is presented and particular attention is paid to the nutritional and processing characteristics of Ultra Whey 99, a whey protein isolate manufactured by Volac International Ltd. The growth of the nutritional bar market in the USA is used to demonstrate the increasing demand for specialist products such as whey protein.  相似文献   

18.
This article analyses the change processes, both personal and professional, undergone by a disparate group of South African educators, within a reflective practice paradigm. The group was involved in a 2-year pilot project based at the Universities of Exeter and Cape Town. The article also examines the impact on the group's teachers of experiencing radically different models of education from those within which they had been raised and still worked. It discusses the outcomes in terms of professional development, motivation, materials production, curriculum innovation and pupil perceptions. The major contributory change factors - political, moral, attitudinal, cultural and professional - are identified and analysed, and further problems and issues raised.  相似文献   

19.
Red table wines of quality are characterized by pleasing and complex mouth-feel sensations, the most important of these being astringency. While a comprehensive set of terms has been developed over time to describe the flavor of red wines, an appropriate vocabulary describing the astringent sensations produced by these wines is not well defined. This paper presents a structured vocabulary derived by a panel of experienced wine tasters that can be used to describe the astringent sub-qualities of red wines. Multidimensional scaling of sorting data showed that an experienced panel and a group of skilled red wine-makers had similar interpretations of the relationships among the astringency terms. A tasting panel was successfully trained to identify and consistently rate the intensity of the astringent sub-qualities encountered in a set of one year old Shiraz wines. A novel approach of using finger touch standards to represent the astringent sensations experienced in the mouth was utilized.  相似文献   

20.
Uncertainties about the long-term prospects of urban water management systems have increased substantially over the past decade due to an increasing variety of regulations, technologies, and demand structures. In Switzerland, this uncertainty is mirrored by growing difficulties of utility managers and (waste)water scientists to agree on shared strategies: Water professionals demand support for pressing management problems, while researchers fundamentally question the longer-term sustainability of the established water management system. To reestablish shared orientation, we conducted a foresight study for the Swiss (waste)water sector in 2004. Based on interviews with 29 experts from Swiss water management and research to collect 56 drivers of change, a team of 17 experts developed three scenarios: (A) regional mergers of water utilities leading to enhanced professionalism in the sector, (B) consequent material flows management leading to a radically restructured urban water management system, and (C) generalized financial crisis leading to a breakdown of centralized utility services. These scenarios helped identifying shared research priorities. We conclude that scenario analysis is a powerful tool for framing long-term strategies, defining priorities, and integrating different interests in the multidisciplinary contexts of sustainability science, which are marked by high uncertainties and concern a wide range of stakeholder groups.  相似文献   

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