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1.
Detailed analyses of persistent organic pollutants (POPs) such as hexachlorocyclohexane (HCH) isomers (HCHs), dichlorodiphenyltrichloro ethane (DDT) and its metabolites (DDTs), hexachlorobenzene (HCB) and congeners of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the coastal estuarine environment of West Bengal, northeast India allowed the evaluation of the contamination status, distribution and possible pollution sources. HCH, DDT, HCB, PCB and PAH were identified compounds in all the samples, whereas the concentrations of chlorinated pesticides (trans-eptachlorepoxide, dieldrin, endrin, metaoxychlor and mirex) were below the detection limits and were not of great concern. The pesticides did demonstrate markedly different distributions reflecting different agricultural and domestic usage in the region. The range of concentrations of HCH, HCB, DDT and PCBs in the sediments were 0.11-0.40, <0.05-0.98, 0.18-1.93 and 0.18-2.33 ng/g dry wt, respectively. Overall elevated levels of HCB, DDT and PCB were recorded at Babughat, a very closely located site of the metropolitan megacity Calcutta. Fluoranthene (flu) and pyrene (py), the dominant 4-ring PAHs, also showed an abrupt elevated concentrations at Babughat with values of 214 and 144 ng/g dry wt, respectively. Among the isomers and metabolites of HCH, DDT and PCB, alpha-HCH, pp'-DDT and PCB (101), PCB (118), PCB(153) and PCB (138) were found to be dominant. High ratios of metabolites of DDT to SigmaDDTs reveal recent use of DDT in this coastal environment. Fluoranthene, pyrene, 1,2-benzo(a)anthracene and chrysene formed the dominant congeners out of 19 identified PAHs. The sources of contamination are closely related to human activities such as domestic and industrial discharge, automobile exhausts, street runoff, slum sewage, agricultural chemicals and soil erosion due to deforestation as well as atmospheric transport. This study is compared to other coastal and estuarine environments in India and abroad. The baseline data can be used for regular ecological monitoring, considering the industrial and agricultural growth around this important estuarine ecosystem.  相似文献   

2.
The sensitivity of nine marine microalgal species (consisting of five divisions and seven genera) to the five heavy metals, Cu(II), As(V), Sb(III), Pb(II) and Cd(II) was studied by using a fluorometric growth-inhibition assay with 96-well microplates. The algal strains studied were Cylindrotheca sp. and the LPP group that respectively characterize aggregating and filamentous types, and Chlorococcum littorale, Chlorococcum sp., Isochrysis galbana, Tetraselmis tetrathele, Heterocapsa sp., Synechococcus sp. and Prasinococcus sp. for types that occur as single cells. A good linear relationship was observed between the chlorophyll a concentration and intensity of chlorophyll fluorescence (485-nm excitation filter and 645-nm emission filter) when the chlorophyll a concentration was within the range of 0.10-5.0 microg ml(-1). A starting cell concentration of 0.10 or 0.25 microg Chl a ml(-1) was therefore selected. In accordance with OECD 201 standard procedures, the IC(50) value (concentration of a metal producing 50% growth inhibition relative to the control) was determined 72 h after adding a heavy metal by using the biomass integral. The microplate toxicity test used in this study is considered to be applicable to diverse algae, not only enumerating species but also hardly enumerating ones.  相似文献   

3.
<正>1.Introduction And now we have Parxit.On 1 June 2017,President Trump issued the highly unpopular announcement that the United States will withdraw from the 2015 Paris Agreement on Climate Change.In this brief piece,I will try to explain the reasons for this nearly unprecedented act of foreign policy folly(Ronald Reagan did pull out of the Law of the Sea  相似文献   

4.
Twenty-five surface sediment samples were collected from Meiliang Bay, Taihu Lake, China, in 2003. The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs), identified as priority pollutants by the USEPA, were determined by gas chromatography equipped with a mass spectrometry detector (GC-MS). Total concentrations of the PAHs ranged from 1207 to 4754 ng/g dry weight. Sediment samples with the highest PAH concentrations were from the northern site of the bay, which is in proximity to the incoming PAH source; the PAH levels in the southern part were relatively low. The observed PAH levels were higher than those in river sediments in China but were lower than those found in sediments of urban areas and harbors. According to the observed molecular indices, PAHs originated largely from the high-temperature pyrolytic process, whereas the petrogenic process was more commonly responsible for PAH contamination in harbors. A good correlation existed between the benzo[a]pyrene level and the total PAH concentration (r=0.97), making benzo[a]pyrene a potential molecular marker for PAH pollution. According to the numerical effect-based sediment quality guideline (SQGs) of the United States, the levels of PAHs at most studied sites in Meiliang Bay, except some sites in the northern part of the bay, should not exert adverse biological effects. In the northern part of the bay, the PAH levels at sites 21 and 22 exceed the effects range low (ERL) and could thus cause acute biological impairments, in comparison with the sediment quality guidelines. The total PAH levels were expressed as the B[a]P toxicity equivalents (TEQs(carc)) and compared to the contaminated sediments from Guba Pechenga, Barents Sea, Russia.  相似文献   

5.
Paul Watson, founder of the Sea Shepherd Conservation Society and captain of anti-whaling ship the Steve Irwin, has emerged as one of the world's most visible environmental protesters. This essay, based in part on a long interview with Watson in Australia in 2009, analyzes his mediated visibility and thus capacity to participate in public debate by isolating various components of his strategic activities under four themes: mediated protest, symbolic power, media practices, and celebrity. It argues that Watson's visibility involves a complex flow of information and meanings across various “old” and “new” media form, but remains reliant on news media. Thus, despite his generally astute media practices and strategies, Watson's visibility is contingent on a set of professional practices and logics unlikely to provide sustained news access or long-term legitimacy to a political “outsider.”  相似文献   

6.
Data on the parasite fauna of the least cisco, Coregonus sardinella Valenciennes, 1848 in Ural tributaries of the Ob downstream of the city of Salekhard have been obtained for the first time. The formation patterns of the parasite fauna in this species and the rate (prevalence and intensity) of infection by Ichthyocotylurus erraticus (Odening, 1969), a parasite specific to coregonids, have been revealed. Infection of the least cisco with six parasite species (out of the 12 species found) occurs as the fish feed on zooplankton and benthic organisms. The dominant parasites are trematode larvae of the genera Ichthyocotylurus and, in some years, Diplostomum; this composition of dominants is evidence that the least cisco fattens up mainly in shallow areas. All sexually mature fish of this species were found to be infected by I. erraticus, but the average intensity of infection was rather low: the abundance index of the parasite did not exceed 40 ind. per fish. Analysis of the distribution of I. erraticus metacercariae in the least cisco shows that the relationship in the host-parasite system is stable and the parasite has no pathogenic effect on individuals of older age classes.  相似文献   

7.
This essay responds to the keynote address by Cox by discussing the ways in which critical rhetoric is implicated in environmental communication (EC) as a crisis discipline, as well as the ways in which EC, so positioned, is implicated within a broader coherentist epistemology. Issues of exigency, representation, and sustainability are considered, along with an examination of the concepts of nominalism and doxa as they relate to the enterprise of EC research. The critical cultural politics embedded in much EC scholarship are also addressed in terms of their intersections with the increasingly unscrupulous abuse of language within antienvironmental administrative rhetorics.  相似文献   

8.
Setting out from Jacques Derrida’s assertion that every act of naming is “a foreshadowing of mourning” ([2008. The animal that therefore I am. (M.-L. Mallet, Ed., D. Wills, Trans.). New York, NY: Fordham University Press], p. 20), this paper argues that the work of earthly coexistence is underwritten by the intertwined practices of naming and mourning. The paper demonstrates that names provide access to and shape our perceptions of earthly entities; that the act of naming prepares us for the work of mourning; that the proper names given to endlings provide poignant points of access to species on the edge of extinction; that species names disclose species as such and, thus, enable us to grieve not just particular living organisms but entire ways of life; and that the name given to the current geological epoch, the “anthropocene,” simultaneously reflects and engenders a mode of awareness which enables us to relinquish those ways of being human that no longer seem sustainable and carry forth those that promise to enrich earthly coexistence.  相似文献   

9.
How to choose among the dozen policy instruments available to environmental management agencies has been a matter of concern and debate among environmental economists for the entire life of the profession – nearly four decades. The ability, or lack of it, to measure the quantities or observe the actions made "enforceable" by particular policy instruments ought clearly to be central to this choice. However, all too often the monitoring problem has been assumed away. When it is reintroduced in realistic forms, we find, not surprisingly, that some favorite policy instruments, such as pollution charges, are not applicable to some important problems, such as runoff pollution from farms; that marginal subsidies, by changing the burden of proof, may no longer be symmetric with charges; and that the apparent freedom from monitoring requirements of the newly fashionable instrument involving the public provision of information about firms or products is "paid for" by our inability to say anything about its performance on other dimensions that are also of interest. Electronic Publication  相似文献   

10.
Mussels are worldwide recognized as pollution bioindicators and used in Mussel Watch programs, because they accumulate pollutants in their tissues at elevated levels in relation to pollutant biological availability in the marine environment. The present study deals with the use of Mytilus galloprovincialis as a local bioindicator of heavy metal and (137)Cs contamination in an estuarine ecosystem (Thermaikos gulf, Greece in Eastern Mediterranean). M. galloprovincialis samples were collected monthly from two aquaculture farms during the period April to October 2000. Analyses for the heavy metals Cu, Cr, Ni, Zn, Fe, Mn and (137)Cs showed that the concentrations measured were low and similar to those from other non-polluted Mediterranean areas. In terms of the two sampling stations, there were no statistically significant differences between them. On the contrary, the seasonal evolution of either heavy metals or (137)Cs levels presented high variation. The levels were found to increase during the cold period of the year, especially for Cu, Zn, Mn and Cr which are essential for life. Stable metals were positively inter-related and moreover, metals more involved in biochemical activities seem to present more correlations than others with less significant role in the metabolism of the organisms.  相似文献   

11.
The effect of Bladex, Etazine, Dicryl, and Baylucide on the growth of the fresh water alga Scenedesmus was investigated. The alga was cultured in various concentrations of the above mentioned pesticides. Scenedesmus was found to be more resistant to Dicryl than to the three other compounds. Dicryl, at a concentration of 2 mg/L, did not lead to complete inhibition of Scenedesmus cells. On the other hand, Bladex, Etazine and Baylucide, at a concentration of 0.5 mg/L, could eliminate the alga from cultures. Examination of Scenedesmus in all testing cultures showed that marked morphological changes and chloroplast disruption occurred especially in the presence of high concentrations of the studied compounds.  相似文献   

12.
Regional Environmental Change - Reliable information on the water balance components today and their future changes is a prerequisite for foresightful and sustainable water management. Basically,...  相似文献   

13.
This article details an integration of geographical information system (GIS) and corpus linguistics (CL) techniques for an ecolinguistic analysis of a contentious, environmental debate in Arizona, USA. The application of GIS and CL procedures enabled the mapping of place name mentions present within two interest group corpora as well as the mapping of particular meanings and representations of specific places prominent in the debate, that is, maps representing both places and the discursive representations of those places were produced. The corpus-aided analysis and the GIS visualizations exhibit how different interest groups refer to and represent geographical places within their texts and how these references to and representations of places index ideological positions towards the mine and the environment. This integrated CL–GIS approach to the study of environmental discourse provides insights into the discursive representation of place and the importance that references to places serve within environmental discourse. The article briefly discusses the ecolinguistics framework underpinning the work, explains the GIS–CL approach, displays and interprets corpus findings and GIS visualizations, and details implications for additional GIS–CL research for environmental discourse.  相似文献   

14.
The variability of the sorption properties (characterized by the distribution coefficient Kd) of a forest soil for Cs, Zn, Sr, Co, Cd, Ce, Ru, Tc, and I were determined along a transect of 150 m in regular intervals of 3 m. Radioactive tracers were used to ensure trace concentrations of these elements. For comparison, for each soil sample the loss on ignition, as a measure of the soil organic matter content, and the pH were also determined. On average, the Kd values increase in the sequence Tc < I < Ru ≈ Co ≈ Zn ≈ Sr < Cd < Ce < Cs; the spatial variability in the sequence I < Zn ≈ Sr ≈ Co ≈ Cd ≈ Ru ≈ Tc < Cs, and I ≈ Ce < Tc. Correlation analysis revealed that, when moving along the transect, the Kd values for some elements changed in a similar, and for others in a dissimilar pattern. In a few cases a correlation between the pH or the loss on ignition and the Kd values was also present. The spatial structure of the data was examined by semivariograms. For the elements Co, Cd, Zn, and Sr, the Kd values showed an almost periodic behaviour along the transect, which is probably due to periodic changes of some soil properties in a forest with regularly spaced trees.  相似文献   

15.
A geochemical study of the Erdek Bay sediments in the Sea of Marmara, Turkey, was carried out to investigate the heavy metal distributions and sources. The bay has an average depth of 34 m and a two-layer water column stratification, with a pycnocline at 20 m. The distribution of "total" metal (Fe, Mn, Pb, Cu, Ni, Cr, Zn and Hg) concentrations, together with sequential selective extraction analyses, shows that the relatively high metal concentrations are mainly due to land-based natural inputs from the erosion products of mineralized zones and mafic-ultramafic rocks delivered to the bay by two rivers from the south. However, some Pb, Zn and Cu occur in the Fe-Mn-oxyhydroxide and organic fractions, suggesting, in part, some anthropogenic inputs in addition to the predominantly natural inputs. The vertical distribution of metal/A1 ratios in a gravity core in the bay shows no significant change with depth, except for an early diagenetic enrichment at 0.7-1.6 m below sea floor (mbsf) above a 4750-3500-year-old sapropelic layer. This distribution is a further indication of the insignificant antropogenic metal pollution in the bay.  相似文献   

16.
In recent years, a number of so-called “farm protection” or “ag-gag” laws have been proposed and passed in state legislatures across the USA. These laws generally ban the undercover photographing or videotaping of industrial animal agricultural production and processing facilities. Proponents of the legislation suggest that such bills protect local farm economies and prevent misinformation campaigns by animal rights activists. Diverse sets of critics have argued against the bills, suggesting that they prevent whistleblowers from exposing animal cruelty and stand in the way of the public's right to know. This paper analyzes the debate by blending theory from science and technology studies regarding the social production of knowledge and ignorance with communication theory that explores the power of storytelling in shaping public understandings of social life. It investigates the stories told by three oppositional stakeholder groups—members of industrial animal agribusiness who defend the legislation, small-scale producers and consumers who believe the legislation prevents productive transparency, as well as animal advocacy and first amendment interests who believe the legislation masks fundamental flaws in the contemporary animal agricultural system. The paper provides insight into how competing mediated narratives frame ideological battles over the present and future of animal production processes. It demonstrates how fundamental and often opposing value systems construct what we consider knowledge and non-knowledge in the context of our contemporary risk society and in the digital media age.  相似文献   

17.
Contributing to extant discourses about corporate environmental advocacy, this paper argues that corporations can embed discursive rhetorical strategies in material places and spaces. This argument contributes to environmental communication by bridging divisions between discursive and materialist approaches to corporate rhetoric. Corporate materiality is realized in the study of Rio Tinto Kennecott (RTK) at places of corporate community where RTK enunciates a dominant environmental discourse about the necessity of the Bingham Canyon Mine through strategies such as the technological shell game, the hypocrite's trap, and corporate heterotopia, which are made manifest materially alongside cultural values such as epistemic trust, technological progress, community, and home. Using participatory critical rhetoric as a methodology, I analyse RTK's material rhetoric at the Natural History Museum of Utah, the Rio Tinto Soccer Stadium, and the Daybreak suburban community. This case study reveals that corporations are assemblages that assert many different, and sometimes competing, arguments that can deflect environmental criticism, materially.  相似文献   

18.
Marine resource management programs face conflicting mandates: to scale-up marine conservation efforts to cover larger areas and meet national and international conservation targets, while simultaneously to downscale and decentralize management authority to resource users and local communities. These conflicting goals create tensions in marine resource management. This paper explores these tensions by presenting and evaluating the outcomes of a fisheries co-management program on the island of Pemba, Tanzania, where institutions and scale were configured and reconfigured under externally funded programs to improve marine conservation through co-management. The initial institutional arrangements for co-management supported a functioning system to protect marine resources, ensure fishermen’s access, and distribute tourism revenues. However, a subsequent push to scale-up marine management reconfigured institutional arrangements and power in a more hierarchical and potentially weaker system. With the expansion of the co-management program, protected area coverage, financial resources, and the number of community organizations created for fisheries co-management expanded tremendously; however, community participation in marine management decreased, and the fishermen’s association previously involved in co-management dissolved. Several factors contributed to this outcome: inadequate time to solidify co-management institutions and arrangements, diverse resource users inexperienced with local management, a sudden and substantial new source of funding, and political pressures to restructure marine management. Rather than focusing primarily on expanding coverage and devolving authority, it is important to adapt co-management arrangements to the local contexts in which they operate.  相似文献   

19.
20.
Eighteen Dutch soils were extracted in aqueous solutions at varying pH. Extracts were analyzed for Cd, Cu, Ni, Pb and Zn by ICP-AES. Extract dissolved organic carbon (DOC) was also concentrated onto a macroreticular resin and fractionation into three operationally defined fractions: hydrophilic acids (Hyd), humic acids (HA) and fulvic acids (FA). In this manner, change in absolute solution concentration and relative percentage for each fraction could be calculated as a function of extraction equilibrium pH. The soils were also analyzed for solid phase total organic carbon and total recoverable metals (EPA Method 3051). Partitioning coefficients were calculated for the metals and organic carbon (OC) based on solid phase concentrations (less the metal or OC removed by the extraction) divided by solution concentrations. Cu and Pb concentrations in solution as a function of extract equilibrium pH are greatest at low and high pH resulting in parabolic desorption/dissolution curves. While processes such as proton competition and proton promoted dissolution can account for high solution metal concentrations at low pH, these processes cannot account for higher Cu and Pb concentrations at high pH. DOC increases with increasing pH, concurrently with the increase in Cu and Pb solution concentrations. While the absolute concentrations of FA and HA generally increase with increasing pH, the relative proportional increase is greatest for HA . Variation in HA concentrations spans three orders of magnitude while FA concentrations vary an order of magnitude over the pH range examined. Correlation analysis strongly suggests that HA plays a major role in increasing the concentration of solution Cu and Pb with increasing pH in the 18 soils studied. The percentage of the OC that was due to FA was nearly constant over a wide pH range although the FA concentration increased with increasing pH and its concentration was greater than that of the HA fraction at lower pH values (pH = 3-5). Thus, in more acidic environments, FA may play a larger role than HA in governing organo-metallic interactions. For Cd, Ni, and Zn, the desorption/dissolution pattern shows high metal solution concentrations at low pH with slight increases in solution concentrations at extremely high pH values (pH>10). The results presented here suggest that the effects of dissolved organic carbon on the mobilization of Cd, Ni, and Zn may only occur in systems governed by very high pH. At high pH, it is difficult to distinguish in this study whether the slightly increased solution-phase concentrations of these cations is due to DOC or hydrolysis reactions. These high pH environments would rarely occur in natural settings.  相似文献   

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