The personal assessments of the current and expected future state of the environment by 3232 community respondents in 18 nations were investigated at the local, national, and global spatial levels. These assessments were compared to a ranking of each country's environmental quality by an expert panel. Temporal pessimism (“things will get worse”) was found in the assessments at all three spatial levels. Spatial optimism bias (“things are better here than there”) was found in the assessments of current environmental conditions in 15 of 18 countries, but not in the assessments of the future. All countries except one exhibited temporal pessimism, but significant differences between them were common. Evaluations of current environmental conditions also differed by country. Citizens' assessments of current conditions, and the degree of comparative optimism, were strongly correlated with the expert panel's assessments of national environmental quality. Aside from the value of understanding global trends in environmental assessments, the results have important implications for environmental policy and risk management strategies. 相似文献
This paper documents the occurrence of polychlorinated biphenyl (PCB) and hexachlorocyclohexane (HCH) deposition inferred from a sedimentary record exposed in a salt-marsh trench in South-Central Chile. Sediments were carefully collected every 1 cm from the trench wall. The samples were analyzed for PCBs, HCHs, 137Cs, organic carbon and grain size. The 137Cs fallout and the sedimentary signature left by the 1960 Chilean tsunami were used as temporal markers to estimate the stratigraphic chronology and the sedimentation rates. PCBs were quantified by gas chromatography with electron capture detection (GC-ECD), and positive samples were confirmed by gas chromatography and mass spectrometry detection (GC-MS). Based on these results, PCBs and HCHs deposition over the last 40 years was estimated. No PCBs were detected below the tsunami signature. Total concentrations ranged from undetectable (ND) to 32 ng/g d.w. for PCBs and from undetectable (ND) to 1.29 ng/g d.w. for HCHs. The highest PCB concentrations were found in the upper 7 cm of the core. Even though PCBs were banned in 1982 as electrical fluids in Chile, total estimated PCB fluxes have increased approximately 20 times during the last 40 years: from undetectable values to 102.6 ng/cm2/year, reflecting that PCBs are still in use and being released into the environment. 相似文献
High infestations of alexandergrass (Brachiaria plantaginea) in experimental area have reduced seedbank of some weed species in soil at a greater degree compared to those obtained with the use of an efficient herbicide. Aconitic acid (AA) has been identified in those plants in high concentration. Thus, two experiments were carried out in the laboratory to determine the effects of pure AA on weed seed germination and on endophytic fungi in wild poinsettia (Euphorbia heterophylla) and morningglory (Ipomoea grandifolia) weed species. Doses of AA (0, 0.5, 1.0, and 2.0 mM) were introduced in agar-water 0.5% medium and weed seeds treated with and without external sterilization by sodium hypochloride. Four replications of fifty seeds of each species by treatment were sown in plastic boxes with cover and maintained in germination chamber for 12 days. Reduction in germination rate, root and stem growth were observed in both species, as well as reduction in root number in morningglory were also observed at 2.0 mM concentration of AA. An increase in number of seeds with presence of endophytic fungi was also observed in both species, independently of seed sterilization, mainly of a green type fungi coloration in wild poinsettia. Aconitic acid presents allelopathic activity and can stimulate endophytic fungi species growth in weed seeds. 相似文献
AbstractCamanducaia River is part of the Piracicaba watershed responsible for pumping water into the Cantareira System, which is one of the main water sources for the metropolis of São Paulo and Campinas, Brazil. Intensive use of pesticides and hilly topography represents a situation of high risk for river water contamination. Therefore, water samples from 12 locations were collected along the Camanducaia River and its tributaries, over a period of 4?mo during the rainy season, and analyzed by GC-MS/MS or UPLC- MS/MS for the presence of 46 pesticides. Seven pesticides (fipronil, methyl parathion, metolachlor, atrazine, carbofuran, diuron, and simazine) were positively detected. Only atrazine (the most frequently detected) and diuron were present at concentrations above the limit of quantification of the analytical method (0.32 and 0.57?μg L?1 for atrazine and diuron, respectively). Pesticides detection frequency was higher than expected for a river system where only 11.8% of the land area is under agriculture. The vulnerability of the Camanducaia basin to pesticide contamination is attributed to the high annual precipitation (> 1.5?m y?1 in the headwaters), associated with topographical features (steep terrain) and soil types that favor surface runoff, which has been exacerbated by poor soil management practices. 相似文献
The electrochemical oxidation of p-substituted phenols, with both electron donor (OH- and NH2-) and electron withdrawing groups (NO2-, COOH-, and halogens), on Pt anodes using sodium sulfate as support electrolyte has been studied. It was found that, except for p-halogen phenols, compounds with electron donor substituents are easier to remove and their initial rates of degradation are correlated to the octanol-water partitioning coefficient (log Poct) and the Hammett's constant. Degradation of all of our starting compounds produced the same intermediates, therefore, a general pathway of reaction is proposed. Additionally, the influence of pH, temperature, electrolyte concentration and current density on the initial and total degradation of p-chlorophenol was also investigated. 相似文献
By means of multivariate techniques, we studied: (1) the differences in the structure of bentho-demersal, non-cryptic, fish
assemblages associated with unvegetated sandy substrates, vegetated meadows constituted by the seagrass Cymodocea nodosa and the bottoms under the influence of sea-cage fish farms; as well as (2) the persistence of these patterns with regard
to different scales of spatial variability, across three islands of the Canarian Archipelago (Central East Atlantic). Our
sampling strategy (involving three islands, with five locations per island, and two sites within each location) detected significant
changes in the composition and structure of the fish assemblages between the three habitats. Fish assemblages associated with
the unvegetated and vegetated bottoms were similar among the surveyed islands. In contrast, we observed a significant inter-island
variability in the fish populations associated with the sea-cage fish farms. The presence of the sea-cage fish farms increased
the overall fish abundance (184.8±49.8 ind 100 m−2) as compared to both the vegetated (38.8±9.7 ind 100 m−2) and unvegetated habitats (1.1±0.4 ind 100 m−2). Differences within and between the habitats were found to be associated with the relative abundance of a few fish species.
The most abundant species were Xyrichthys novacula in the unvegetated bottoms and Diplodus annularis, Spondyliosoma cantharus and Mullus surmuletus on the seagrass meadows. Finally, we recorded an increase in the abundance of Heteroconger longissimus, Trachinus draco and Pagellus acarne in the bottoms beneath the sea-cage fish farms. These species, in addition to a group of large benthic chondrichthyes, were
responsible for the differences between islands in the composition and structure of the demersal ichthyofauna beneath the
sea-cage fish farms. 相似文献
Schroederichthys chilensis is a common shark that lives in Chilean coastal environments. In this work, the relationship between liver 7-ethoxyresorufin-O-deethylase dealkylation (EROD) activity and Fluorescent Aromatic Compounds (FAC) in bile of S. chilensis sampled in three bays with different degrees of pollution were performed including a reference area. Sixty individuals were collected, 20 for each site; (10 males and 10 females per site) livers and bile samples were obtained and immediately frozen. EROD activity and FAC were measured according to three standard methods. EROD activity and FAC were higher in polluted areas than in the reference area. Synchronous Fluorescence Spectra of the bile from the fish collected at the most polluted area showed a peak at 347nm representing a metabolite corresponding to 1-hydroxypyrene. The low EROD activity in the reference area is likely related to the low level of PAH in sediments. We propose that this species is a good indicator of exposure to FACs, since it presents a series of characteristics that make it suitable for monitoring PAH exposure in coastal zones. 相似文献
Objective: The aim of this study is to evaluate, through a systematic review of hospital-based studies, the proportion of road traffic injuries and fatalities in sub-Saharan Africa (SSA).
Methods: In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology guidelines, we searched the following electronic databases: PubMed, Embase, Africa-Wide Information, Global Health, and Web of Science. Articles were eligible if they measured proportion of road traffic injuries (RTIs) in SSA by using hospital-based studies. In addition, a reference and citation analysis was conducted as well as a data quality assessment.
Results: Up to 2015, there were a total of 83 hospital-based epidemiologic studies, including 310,660 trauma patients and 99,751 RTI cases, in 13 SSA countries. The median proportion of RTIs among trauma patients was 32% (4 to 91%), of which the median proportion of death for the included articles was 5% (0.3 to 41%).
Conclusion: The number of studies evaluating RTI proportions and fatalities in SSA countries is increasing but without the exponential rise expected from World Health Organization calls for research during the Decade of Action for Road Traffic Injuries. Further research infrastructure including standardization of taxonomy, definitions, and data reporting measures, as well as funding, would allow for improved cross-country comparisons. 相似文献