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1.
The trends of yearly emission of sulphur dioxide are analysed for the European Union during a period of time from 1985 to 1997. To achieve the above matter the method of the least squares model has been used. Major SO2emissions were found in Germany, the United Kingdom, Spain, Italy and France. However, high SO2emissions by km2were found in Germany, the United Kingdom and Belgium. The most remarkable results of the trend analysis appears as follows: 12 countries with significant downward trends, 2 countries with significant upward trends and 1 country with no significant trend. A decreasing trend is evident for the most part of the E.U., although Portugal and Greece generated significant increasing trends of SO2emission for the mentioned year period.  相似文献   

2.
Data from National Health and Nutrition Examination Survey for children aged 6–11 years for 1999–2014 were used to study time trends and factors affecting the urinary levels of barium, cobalt, cesium, molybdenum, lead, antimony, thallium, and tungsten. Adjusted levels in urine declined every two years by 5.9% for barium, by 1.2% for cesium, by 18.2% for lead, and by 14% for antimony. For every additional smoker smoking inside a home, the levels of barium increased by 10.6% and for lead by 10%, but for tungsten levels decreased by 7.7%.  相似文献   

3.
This study estimates the detailed chemical profiles of China's anthropogenic volatile organic com- pounds (VOCs) emissions for the period of 2005-2020. The chemical profiles of VOCs for seven activity sectors are calculated, based on which the Photochemical Ozone Creation Potential (POCP) of VOCs for these sectors is evaluated. At the national level, the VOCs species emitted in 2005 include alkanes, alkenes and alkynes, aromatic compounds, alcohols, ketones, aldehydes, esters, ethers and halocarbons, accounting for 26.4wt.%, 29.2wt.%, 21.3 wt.%, 4.7 wt.%, 5.4 wt.%, 1.7 wt.%, 2.1 wt.%, 0.7 wt. % and 2.2wt.% of total emissions, respectively. And during 2005-2020, their mass proportions would respec- tively grow or decrease by - 34.7%, -48.6%, 108.5%, 6.9%, -32.7%, 7.3%, 65.3%, 100.5%, and 55.4%. This change would bring about a 13% reduction of POCP for national VOCs emissions in the future. Thus, although the national VOCs emissions are expected to increase by 33% over the whole period, its ozone formation potential is estimated to rise only by 14%. Large discrepancies are found in VOCs speciation emissions among provinces. Compared to western provinces, the eastern provinces with a more developed economy would emit unsaturated hydrocarbons and benzene with lower mix ratios, and aromatic compounds except benzene, oxidized hydrocar- bons and halocarbons with higher mix ratios. Such differences lead to lower POCP of VOCs emitted in eastern provinces, and higher POCP of VOCs emitted in western provinces. However, due to the large VOCs emissions from Chinese eastern region, the ozone forma- tion potential of VOCs emission in eastern provinces would be much higher than those in western provinces by about 156%-235%.  相似文献   

4.
Many lupine species (Genus Lupinus) contain toxic compounds, although the amount of these substances varies by the plant part and species. This investigation described the epidemiology of 138 lupine exposures reported to Texas poison centers during 1998–2005. Almost 88% of the lupine exposure calls occurred in March and April, and 90% of the calls came from the central portions of the state. Sixty-one percent of the calls involved female patients, and 91% of the patients were age <6 years. The lupine exposure occurred at the patient's own residence in 79% of the cases. Of the reported lupine exposures, 93% were handled outside of health care facilities, and, of those cases with a known medical outcome, few moderate or major effects, and no deaths, were reported. The most frequently noted clinical effect among cases during 2000–2005 was vomiting, affecting 8% of the cases. In conclusion, most reported lupine exposures in Texas came from the central parts of the state, occurred in spring, and involved young children. Typical reported lupine exposures in Texas were not likely to have adverse outcomes.  相似文献   

5.
6.
The purpose of this study was to describe a large number of lionfish envenomations reported to poison control centers. Cases were lionfish envenomations reported to Texas poison control centers during 1998–2006. The distribution of cases was determined for selected parameters. A total of 188 cases were identified. Of the cases with a known location of envenomation, 94% involved the finger or hand. The patient was male in 72% of the cases, and the mean age was 32 years (range 4–65 years). The most frequently reported adverse clinical effects were dermal pain (89%) and a puncture or wound (66%). The most commonly reported treatments were immersion in hot water (84%) and tetanus antitoxin/status (48%). Patients with lionfish envenomations reported to Texas poison control centers were most often adults and males. The reported adverse clinical effects were typical of lionfish envenomations, and the treatments were generally consistent with the recommended guidelines.  相似文献   

7.
Centipedes are found globally, including the southern United States. Although centipede bites may cause pain, the bite is generally not considered life threatening. The present retrospective investigation studied the epidemiology of centipede exposures reported to Texas poison control centers. Cases were all human exposures reported during 1998–2004 that involved centipedes. There were totally 851 cases. Among the cases with a known patient age, 16% were less than 6 years of age, 19% were 6–19, and 65% were greater than 19 years. Females accounted for 55% of the patients with known gender. The reported centipede exposures were managed on site (outside of a health care facility) in 93% of the cases. Of the 305 cases with a known clinical outcome, 82% had minor effects. Cases exhibited a seasonal trend, with most of the reports occurring during July–September. There was no clear geographic pattern to the reported centipede exposures, although the highest rate occurred in West Texas. Dermal irritation or pain was reported in 73% of cases and the treatment by decontamination via irrigation was reported for 76% of the cases during 2000–2004.  相似文献   

8.
The seasonal productivity cycle and factors controlling annual variation in the timing and magnitude of the winter–spring bloom were examined for several locations (range: 42°20.35′–42°26.63′N; 70°44.19′–70°56.52′W) in Boston Harbor and Massachusetts Bay, USA, from 1995 to 1999, and compared with earlier published data (1992–1994). Primary productivity (mg C m−2 day−1) in Massachusetts Bay from 1995 to 1999 was generally characterized by a well-developed winter–spring bloom of several weeks duration, high but variable production during the summer, and a prominent fall bloom. The bulk of production (mg C m−3 day−1) typically occurred in the upper 15 m of the water column. At a nearby Boston Harbor station a gradual pattern of increasing areal production from winter through summer was more typical, with the bulk of production restricted to the upper 5 m. Annual productivity in Massachusetts Bay and Boston Harbor ranged from a low of 160 g C m−2 year−1 to a high of 787 g C m−2 year−1 from 1992 to 1999. Mean annual productivity was higher (mean=525 g C m−2 year−1) and more variable near the harbor entrance than in western Massachusetts Bay. At the harbor station productivity varied more than 3.5-fold (CV=40%) over an 8 year sampling period. Average annual productivity (305–419 g C m−2 year−1) and variability around the means (CV=25–27%) were lower at both the outer nearfield and central nearfield regions of Massachusetts Bay. Annual productivity in 1998 was unusually low at all three sites (<220 g C m−2 year−1) due to the absence of a winter–spring phytoplankton bloom. Potential factors influencing the occurrence of a spring bloom were investigated. Incident irradiance during the winter–spring period was not significantly different (P > 0.05) among years (1995–1999). The mean photic depth during the bloom period was significantly deeper (P < 0.05) in 1998, signifying greater light availability with depth. Nutrients were also in abundance during the winter–spring of 1998 with stratified conditions not observed until May. In general, the magnitude of the winter–spring bloom in Massachusetts Bay from 1995 to 1999 was significantly correlated with winter water temperature (r 2=0.78) and zooplankton abundance (r 2=0.74) over the bloom period (typically February–April). The absence of the 1998 bloom was associated with higher than average water temperature and elevated levels of zooplankton abundance just prior to, and during, the peak winter–spring bloom period. Received: 3 July 2000 / Accepted: 6 December 2000  相似文献   

9.
Large rivers often present a river–lakedelta system, with a wide range of temporal and spatial scales of the flow due to the combined effects of human activities and various natural factors, e.g., river discharge, tides, climatic variability, droughts, floods. Numerical models that allow for simulating the flow in these river–lakedelta systems are essential to study them and predict their evolution under the impact of various forcings. This is because they provide information that cannot be easily measured with sufficient temporal and spatial detail. In this study, we combine one-dimensional sectional-averaged (1D) and two-dimensional depth-averaged (2D) models, in the framework of the finite element model SLIM, to simulate the flow in the Mahakam river–lakedelta system (Indonesia). The 1D model representing the Mahakam River and four tributaries is coupled to the 2D unstructured mesh model implemented on the Mahakam Delta, the adjacent Makassar Strait, and three lakes in the central part of the river catchment. Using observations of water elevation at five stations, the bottom friction for river and tributaries, lakes, delta, and adjacent coastal zone is calibrated. Next, the model is validated using another period of observations of water elevation, flow velocity, and water discharge at various stations. Several criteria are implemented to assess the quality of the simulations, and a good agreement between simulations and observations is achieved in both calibration and validation stages. Different aspects of the flow, i.e., the division of water at two bifurcations in the delta, the effects of the lakes on the flow in the lower part of the system, the area of tidal propagation, are also quantified and discussed.  相似文献   

10.
Now, there is a decreasing trend for the prevalence rate of Kaschin–Beck disease (KBD) in most parts of China, but the disease is still active and severe in the Tibetan Plateau for some reason. To further explore the role of selenium in the occurrence of KBD, We collected samples including drinking water, cultivated topsoil, Highland Barley grains, and tsamba in Rangtang County and Aba County, Sichuan Province and determined concentrations of selenium by Hydride Generation Atomic Fluorescence Spectrometry. Levels of selenium in the environment were analyzed in detail. Selenium in the soil–plant–food system and their relationship with prevalence rate of KBD were also discussed. The results indicate: (a) the levels of environmental selenium are very low and the study area belongs to a selenium-deficient ecological landscape; (b) the KBD becomes much more severe with decreasing environmental selenium under the selenium-deficient condition. Namely, the lower the environmental selenium is, the more severe the disease is; (c) soil selenium deficiency plays a critical role for the prevalence of local KBD, and more factors inducing selenium deficiency should be more concerned in the future.  相似文献   

11.
Keshan disease (KD) occurs in a wide geographic belt stretching from the Heilongjiang Province in northeastern China to Yunnan Province in southwestern China, including Huangling County, Shaanxi Province. In order to research relationships between eco-environmental geochemistry and KD pertaining to Se, Mo, B, Zn, Mn, and Cu, this investigation was conducted in the Jiantou KD area in Huangling County, one of the areas in China where the incidence of KD is highest. Environmental samples (rock, soil, plant and childrens hair) were collected from the area. Se in plants is low, ranging from 0.03 to 0.06 µg Se g–1 in corn, potato and soybean. Se contents in childrens hair are normal or reach the limitation of dangerous level. This study reports 0.18 µg Se g–1, B <40 µg g–1, and Mo <1.0 µg g–1 in aeolian soil, 0.14–0.38 µg Mo g–1 and 3–8 µg B g–1 in corn and potato (daily staple food for local human beings in the area). The Jiantou KD area is one where the elements Se, Mo and B are deficient. It is proposed that the deficiency of elements Se, Mo and B may be involved in the pathogenicity of KD with respect to the eco-environmental system because Se, Mo and B are essential micronutrients for plants and human beings. It seems that there is no significant relationship between the Zn–Mn–K–Pb–Ba associations and KD.  相似文献   

12.
The confusion effect describes the observed decrease in the likelihood that a predator will successfully catch any prey when attacking larger groups of moving prey. We introduce readers to the work of cognitive psychologists interested in human visual attention who have been studying their own version of the confusion effect for many years, developing methods and concepts that may be of fundamental utility to behavioral ecologists. In psychology, ‘basic features’ are characteristics unique to a target object in the visual field that no distracter objects share. Images containing targets with basic features are often less likely to induce the confusion effect in human subjects. Target objects with conjunctions of features, on the other hand, have no individual characteristics unique from distracters, but unique characteristics in combination. Such targets more often induce the confusion effect in humans. We propose the ‘basic feature’ (vs. conjunctions of features) as a new organizing concept for studies on the occurrence of the confusion effect in nature, potentially allowing predictions about which types of prey groups are likely to induce the confusion effect in predators.  相似文献   

13.
Organic reactions in aqueous media are being developed because water is environmentally benign. The Horner–Wadsworth–Emmons reaction is a modified Wittig reaction for the synthesis of α,β-unsaturated ketones and other conjugated compounds. Here we prepared high molecular weight ketones by the Horner–Wadsworth–Emmons reaction of dimethyl-2-oxopropylphosphonate and various aldehydes in water at room temperature. The product was precipitated during the reaction process and was separated readily by a simple filtration in 90–99 % yield.  相似文献   

14.
The temporal variation in metal concentrations in soil and vegetation samples collected in an area of Catalonia (Spain), which will be under the potential influence of a new hazardous waste incinerator was determined. In 1996 and again in 1998, As, Be, Cd, Cr, Hg, Mn, Ni, Pb, Sn, Tl and V were measured in 40 soil and 40 herbage samples collected at 250–4000 m from the facility at the same sampling points. Data of both surveys and the percentages of variation are here presented for all metals. Results are shown according to the main wind directions in the area, as well as distances from the new facility. During the period 1996–1998, a general decrease was noted for most metals. Only the levels of Hg were significantly increased during this period. The present results will be useful for future surveys aimed to evaluate the environmental impact of metals derived from emissions of the new plant.  相似文献   

15.
There has been a growing interest on using local modelling techniques for the analysis of spatio-temporal data because of their powerfulness in extracting the underlying local patterns in the data. In this study, we propose a two-step local smoothing approach to explore spatial patterns and temporal trends of spatio-temporal data via combining the geographically weighted regression and the local polynomial smoothing procedure. The proposed method incorporates both spatial and temporal information into the calibration process and makes it easier to implement visualization of the results. A simulation experiment is conducted to assess the performance of the proposed method and the results show that the method works satisfactorily. A real-world spatio-temporal data set is analyzed to demonstrate the practical usefulness of the method.  相似文献   

16.
17.
While it is known that Antarctic sea ice biomass and productivity are highly variable over small spatial and temporal scales, there have been very few measurements from eastern Antarctic. Here we attempt to quantify the biomass and productivity and relate patterns of variability to sea ice latitude ice thickness and vertical distribution. Sea ice algal biomass in spring in 2002, 2003 and 2004 was low, in the range 0.01–8.41 mg Chl a m−2, with a mean and standard deviation of 2.08 ± 1.74 mg Chl a m−2 (n = 199). An increased concentration of algae at the bottom of the ice was most pronounced in thicker ice. There was little evidence to suggest that there was a gradient of biomass distribution with latitude. Maximum in situ production in 2002 was approximately 2.6 mg C m−2 h−1 with assimilation numbers of 0.73 mg C (mg Chl a)−1 h−1. Assimilation numbers determined by the 14C incubations in 2002 varied between 0.031 and 0.457 mg C (mg Chl a)−1 h−1. Maximum fluorescence quantum yields of the incubated ice samples in 2002 were 0.470 ± 0.041 with E k indices between 19 and 44 μmol photons m−2 s−1. These findings are consistent with the shade-adapted character of ice algal communities. In 2004 maximum in situ production was 5.9 mg C m−2 h−1 with an assimilation number of 5.4 mg C (mg Chl a)−1 h−1. Sea ice biomass increased with ice thickness but showed no correlation with latitude or the time the ice was collected. Forty-four percent of the biomass was located in bottom communities and these were more commonly found in thicker ice. Surface communities were uncommon.  相似文献   

18.
19.
More than 150 scientists from the Americas, Europe, and Asia met in Brno, Czech Republic, in May 2002 at the Second PCB Workshop, entitled “Recent Advances in the Environmental Toxicology and Health Effects of PCBs”. NIEHS/EPA-Superfund Basic Research Program, the Graduate Center for Toxicology at the University of Kentucky, and the Research Centre for Atmospheric and Environmental Chemistry and Ecotoxicology of Masaryk University, Brno, sponsored the Workshop. At six separate sessions (including posters) the origins, human residues and exposures, actions, biomarkers, risk and remediation issues relating to PCBs were discussed.  相似文献   

20.
The concentrations of total phosphorus (TP) from 83 surface water sampling sites in 29 of the Chinese Ecosystem Research Network (CERN) monitored ecosystems, representing typical agro- and forest ecosystems, were assessed using monitoring data collected between 2004 and 2010 from still and flowing surface water. Results showed that, TP concentrations were significantly higher in agro-ecosystems than those in forest ecosystems both for still and flowing surface water. For agro- ecosystems, TP concentrations in the southern area were significantly higher than those in the northern and north- western areas for both still and flowing surface water, however no distinct spatial pattern was observed for forest ecosystems. In general, the median values of TP within agro- and forest ecosystems did not exceed the Class V guideline for still (0.2mg.L-1) or flowing (0.4mg.L-1) surface water, however, surface water at some agro- ecosystem sampling sites was frequently polluted by TE Elevated concentrations were mainly found in still surface water at the Changshu, Fukang, Linze and Naiman monitored ecosystems, where exceedance (〉 0.2 mg.L-1) frequencies varied from 43% to 78%. For flowing water, elevated TP concentrations were found at the Hailun, Changshu and Shapotou monitored ecosystems, where exceedance (〉 0.4 mg. L-1) frequencies varied from 29% to 100%. Irrational fertilization, frequent irrigation and livestock manure input might be the main contributors of high TP concentrations in these areas, and reduced fertilizer applications, improvements in irrigation practices and centralized treatment of animal waste are necessary to control P loss in these TP vulnerable zones.  相似文献   

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