共查询到20条相似文献,搜索用时 31 毫秒
1.
Zhi Gang Huang Ye Xiao Fei Yang Si Liang Huang Yu Ying Li 《Regional Environmental Change》2016,16(5):1333-1343
Returning farmland to forests is important for the protection of ecological values. Eucommia ulmoides is considered to be a suitable species for reforestation in the hilly red soil region of southern China. The objective of this study was to investigate the relationship between the water supply and demand of an E. ulmoides plantation to provide insights into the feasibility of large-scale planting for ecological restoration and forest management activities in the hilly red soil region of southern China. With the measured precipitation, surface runoff and interflow and actual evapotranspiration (ETc) estimated by the modified P–M model, soil water storage (SWS) was estimated based on the water balance equation. Monthly variations of SWS were then compared with in situ measured SWS. The results showed that the estimated mean monthly water losses (the sum of the surface runoff, interflow and ETc) were 139.8 mm in a wet year and 120.0 mm in a dry year, while the measured mean monthly water input values (net precipitation) were 131.2 mm in a wet year and 70.8 mm in a dry year. Net soil water storage (ΔSWS) was negative in each month of the growing season in a dry year, but the soil water deficit was replenished during the following season. The model performance showed that the modified P–M model can be adapted to estimate the soil water storage in other forest catchments where no adequate in situ data are available. As a result of estimating the water balance and observing soil water storage in two different hydrological years, E. ulmoides is recommended as a suitable forest rehabilitation species in the study area, and a suitable plant region has been defined by the GIS technique based on the water balance model. 相似文献
2.
Kurnaz A Kucukomeroglu B Damla N Cevik U 《Journal of environmental radioactivity》2011,102(4):393-399
The activity concentrations and absorbed gamma dose rates due to primordial radionuclides and 137Cs have been ascertained in 222 soil samples in 18 counties of the Trabzon province of Turkey using a HPGe detector. The mean activity concentrations of 238U, 232Th, 40K and 137Cs in soil samples were 41, 35, 437 and 21 Bq kg−1, respectively. Based on the measured concentrations of these radionuclides, the mean absorbed gamma dose in air was calculated as 59 nGy h−1 and hence, the mean annual effective dose due to terrestrial gamma radiation was calculated as 72 μSv y−1. In addition, outdoor in situ gamma dose rate (D) measurements were performed in the same 222 locations using a portable NaI detector and the annual effective dose was calculated to be 66 μSv y−1 from these results. The results presented in this study are compared with other parts of Turkey. Radiological maps of the Trabzon province were composed using the results obtained from the study. 相似文献
3.
A multiple criteria evaluation of sustainable agricultural development models using AHP 总被引:2,自引:0,他引:2
Selection of the appropriate agricultural development model has become an important issue in Iran. Using data from Fars province
of Iran, the purpose of this paper is to use analytic hierarchy process (AHP) for selecting between the two competing sustainable
agricultural development models, which have been developed based on the general tenets of Ecological Modernization (EM) and
De-Modernization (DM) theories. Farmers, environmentalists, board members of rural cooperative, rural women and experts from
Fars Agricultural (Jehad-e-Keshavarzi) Organization participated in application of AHP to this study. They applied AHP to
determine the priority of DM and EM based sustainable agricultural development models. Each group determined the priority
of the two models for sustainable agricultural development. The findings indicated that ecological criteria i.e. wise use
of resources, environmental protection and product quality are the most important criteria for sustainable agriculture of
Iran, followed by economic criterion employment and social criterion participation. A sensitivity analysis was carried out
to determine the critical factors that affected the priority of alternatives. The results indicated that EM-based sustainable
agricultural development model has a higher priority as the theoretical base of agricultural development of Iran.
Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue 相似文献
4.
Parameters of reproduction of the Siberian stone pine (Pinus sibirica), including radial and apical tree increments, the age structure of stands, the amount of young growth, and its distribution along an altitudinal gradient, have been studied in the forest-tundra ecotone of the Western Sayan. The results show that, over the past 30 years, P. sibirica undergrowth has expanded to the mountain tundra belt, the apical and radial tree increments and stand density have increased, and the life form of many P. sibirica plants has changed from prostrate to erect (single-or multistemmed). These changes correlate with the dynamics of summer temperatures and monthly (in May and June) and annual precipitation. The rise of summer temperatures by 1°C promotes the expansion of P. sibirica undergrowth for approximately 150 m up the altitudinal gradient. 相似文献
5.
E. V. Shuyskaya L. G. Gismatullina K. H. Toderich P. Yu. Voronin N. V. Soldatova 《Russian Journal of Ecology》2012,43(4):302-306
Populations of Haloxylon àphyllum in the Kyzylkum Desert have been found to be markedly deficient in heterozygotes at a medium level of genetic diversity (P 95 = 0.56, A = 1.67, H o = 0.14, H e = 0.28). Spatial genetic differentiation of these populations have been revealed along a soil salinity gradient (from 0 to 0.5 mmol Na+/g), with their genetic diversity reaching a maximum (H o = 0.21?C0.25, H e = 0.25?C0.27) in areas with a moderate salinity level (0.05?C0.1 mmol Na+/g). Locus Got-2 can serve as a marker of this differentiation (FstGot-2 = 0.4). 相似文献
6.
Farnaz Pourzand Mohammad Bakhshoodeh 《Environment, Development and Sustainability》2014,16(3):671-688
Fars has a special place in Iran in terms of natural resources and diverse climate aiming this province to increase production of major crops such as corns. In light of increasing domestic production and preventing yield loss of maize, many farmers utilize high quantities of pesticides, chemical fertilizers and over-extract groundwater without considering immediate and long-term consequences of such operations on environment. The main purpose of this study is to investigate technical efficiency and sustainability–technology gap ratio (STGR) of maize producers by agricultural sustainability in Fars province in Iran. Technical efficiency is considered as a key element among the triple elements of sustainable development (economic, social and ecological). Applying model of agricultural sustainability and compromise programming method, regions were classified into three groups (sustainable, relatively sustainable and unsustainable), and data were collected interviewing a total of 300 farmers in 2008–2009 from Kazerun, Firouzabad and Marvdasht chosen randomly and systematically as representatives of these three groups. Technical efficiencies and STGRs were calculated for the regions applying stochastic production frontier, regional stochastic frontier functions and the metafrontier. The results indicate that assuming the same technology between the fields (traditional methods) leads to overestimation of technical efficiency. Mean STGRs in Marvdasht, Firouzabad and Kazerun were found to be 59.3, 71.1 and 68.9, respectively. This suggests that technical efficiency and STGR of relatively sustainable regions are higher than those of the unsustainable regions. Thus, farmers in these areas can reduce gap between technology and agricultural sustainability levels via achieving metatechnology that is compatible with sustainable agriculture. 相似文献
7.
Mehrzad Kherad Hossein Ahani Mohammad Reza Kousari Arman Beyraghdar Kashkooli Mohammad Amin Karampour 《Environment, Development and Sustainability》2013,15(4):1129-1142
Fars Comprehensive Agricultural Database was created to remove bottlenecks and constrains of province for decision makers in a way that leads to sustainable agriculture. Regarding Fars agricultural comprehensive information database, and the importance of wheat as the strategic commodity, this study was conducted in Ali-Abad-e-Kamin (Pasargad, Iran) to assess two most important managerial factors affecting other agricultural factors. Therefore, in this study, besides evaluating the effect of water resource on wheat yield and other traits, education impacts were analyzed and evaluated as well. Data were collected regarding cadastre land use information derived from satellite imagery combined with GIS potencies, and also a comprehensive questionnaire was completed to collect local field information. Results revealed that educational level has significant effect on crop yield, fields’ area and seed consumption rate and also effect of water resource showed significant difference for crop yield, fields’ area. Finally, interactive effect of water resource and educational level showed significant difference just for wheat yield. Also, as a result, higher education positively results in improved wheat yield, lands’ area and seed consumption rate. On the other hand, river as a type of sustainable water resource with karstic geological formations positively affected wheat yield, lands’ area and farms distance from village. Overall, transferring knowledge from relevant organization resulting in higher productivity seems to be necessary. 相似文献
8.
To assess the stability of individual development of the pygmy wood mouse (Apodemus uralensis) in mountain areas with different ecogeographic conditions, the levels of fluctuating asymmetry in a series of skull phenes have been evaluated in ten samples from the Western and Central Caucasus. Attention has been focused on the influence of change in environmental conditions along the elevational gradient and the impact of some anthropogenic factors. An increase in the index of fluctuation asymmetry FAnm has been revealed in samples from populations exposed to pollutants and, in the absence of pollution, from areas where the average annual temperature drops below 5°С (mid-mountain regions). Instability of skull development observed in A. uralensis from the foothills of the Western Caucasus may be a consequence of competitive relationships with the Black Sea field mouse A. ponticus, a sympatric species that inhabits the same biotopes as does A. uralensis but numerically prevails over it. 相似文献
9.
Concentrations of the natural radionuclides 238U, 226Ra, 232Th and 40K have been measured by γ-ray spectrometry in 796 topsoil samples from the Pearl River Delta Zone (PRDZ) of Guangdong, China. The mean concentrations for 238U, 226Ra, 232Th and 40K were found to be 140 ± 37 Bq kg−1, 134 ± 41 Bq kg−1, 187 ± 80 Bq kg−1 and 680 ± 203 Bq kg−1 dry mass, respectively. These values were all higher than the mean values in soil for China and the world. Outdoor air-absorbed dose rates, calculated from activity concentrations of 226Ra, 232Th and 40K, ranged from 86 to 237 nGy h−1, with a mean value of 165 ± 46 nGy h−1. The corresponding annual outdoor effective dose rate per person was estimated to be between 0.11 and 0.29 mSv y−1, with a mean value of 0.20 ± 0.06 mSv y−1, which was also higher than the world mean value of 0.07 mSv y−1. The radium equivalent activity (Raeq) and the external hazard index (Ir) resulted from the natural radionuclides in soil, were also calculated and found to vary from 230 to 676 Bq kg−1 and from 0.6 to 1.8, respectively. The Raeq and the Ir in all the investigated regions were up to 75% higher than the set limits of 370 Bq kg−1 and 1.0, respectively. 相似文献
10.
The current research was carried out to find the most effective environmental factors in plant species occurrence and providing
their predictive habitat models. For this purpose, study was conducted in Poshtkouh rangelands of Yazd province in the central
of Iran. For modeling, vegetation data in addition to site condition information including topography, climate, geology and
soil were prepared. CCA and Logistic regression (LR) techniques were implemented for plant species predictive modeling. To
plants predictive mapping, it is necessary to prepare the maps of all affective factors of models. To mapping soil characteristics,
geoestatistical method including variogram analysis and Kriging interpolation were used. Based on obtained predictive models
for each species (through LR method) and for whole species (through CCA method) related predictive maps were prepared in GIS.
The accuracy of predictive maps were tested with actual vegetation maps. Vegetation modeling results with CCA indicates that
predictive map of vegetation corresponds with actual map (with high accuracy). Predictive maps of Cornulaca monachantha, Ephedra strobilacea-Zygophyllum eurypterum, Seidlitzia rosmarinus, and Tamarix ramosissima, which have narrow amplitude, has high accordance with actual vegetation map prepared for the study area. Among species of
study area, predictive model of Artemisia sieberi, due to its ability to grow in most parts of Poshtkouh rangelands with relatively different habitat conditions, is not possible.
Comparing CCA and LR methods showed that each technique has its advantages and drawbacks. In general, LR will provide better
specific-model, but CCA will provide a broader overview of multiple species. 相似文献
11.
Land cover changes as impacted by spatio-temporal rainfall variability along the Ethiopian Rift Valley escarpment 总被引:1,自引:0,他引:1
Sofie Annys Biadgilgn Demissie Amanuel Zenebe Abraha Miro Jacob Jan Nyssen 《Regional Environmental Change》2017,17(2):451-463
Magnitudes of land cover changes nowadays can be assessed properly, but their driving forces are subject to many discussions. Next to the accepted role of human influence, the impact of natural climate variability is often neglected. In this paper, the impact of rainfall variability on land cover changes (LCC) is investigated for the western escarpment of the Raya Graben along the northern Ethiopian Rift Valley. First, LCC between 2000 and 2014 were analysed at specific time steps using Landsat imagery. Based on the obtained LCC maps, the link was set with rainfall variability, obtained by means of the satellite-derived rainfall estimates (RFEs) from NOAA-CPC. After a correction by the incorporation of local meteorological station data, these estimates prove to be good estimators for the actual amount of precipitation (ρ RFE1.0 = 0.85, p = 0.00, n = 126; ρ RFE2.0 = 0.76, p = 0.00, n = 934). By performing several linear regression analyses, a significant positive relationship between the precipitation parameter DIFF 5Y (i.e. the at-RFE pixel scale difference in five-year average annual precipitation for the two periods preceding the land cover maps) and the changes in the woody vegetation cover was found (standardised regression coefficient β = 0.23, p = 0.02, n = 108). Despite the dominance of direct human impact, further greening of the study area can be expected for the future concomitantly to a wetter climate, if all other factors remain constant. 相似文献
12.
There has been an increase in oil sands development in northern Alberta, Canada and an overall increase in economic activity in the province in recent years. An evaluation of the state of air quality was conducted in four Alberta locations – urban centers of Calgary and Edmonton, and smaller communities of Fort McKay and Fort McMurray in the Athabasca Oil Sands Region (AOSR). Concentration trends, diurnal hourly and monthly average concentration profiles, and exceedances of provincial, national and international air quality guidelines were assessed for several criteria air pollutants over the period 1998 to 2014. Two methods were used to evaluate trends. Parametric analysis of annual median 1 h concentrations and non-parametric analysis of annual geometric mean 1 h concentrations showed consistent decreasing trends for NO2 and SO2 (< 1 ppb per year), CO (< 0.1 ppm per year) at all stations, decreasing for THC (< 0.1 ppm per year) and increasing for O3 (≤ 0.52 ppb per year) at most stations and unchanged for PM2.5 at all stations in Edmonton and Calgary over a 17-year period. Little consistency in trends was observed among the methods for the same air pollutants other than for THC (increasing in Fort McKay < 0.1 ppm per year and no trend in Fort McMurray), PM2.5 in Fort McKay and Fort McMurray (no trend) and CO (decreasing < 0.1 ppm per year in Fort McMurray) over the same period. Levels of air quality indicators at the four locations were compared with other Canadian and international urban areas to judge the current state of air quality. Median and annual average concentrations for Alberta locations tended to be the smallest in Fort McKay and Fort McMurray. Other than for PM2.5, Calgary and Edmonton tended to have median and annual average concentrations comparable to and/or below that of larger populated Canadian and U.S. cities, depending upon the air pollutant. 相似文献
13.
《Journal of environmental radioactivity》1986,4(1):39-64
Few analytical techniques are sensitive enough to detect environmental concentrations of uranium in waters where humic acids are present. One objective of this study was to devise a technique for measuring humic-complexed and uncomplexed uranium at these concentrations. Three techniques were combined to determine the binding capacity and conditional stability constant of uranium with Aldrich® humic acid. Free UO22+ was separated from bound by chelating resin; the CC bonds were destroyed by photo-oxidation and UO22+ was quantified by laser fluorometry. The binding capacity (BC) of 3·5 mg C liter−1 Aldrich humic acid solution was estimated to be 1·14 × 10−6MUO22+ with an asymptotic standard error of 5·0 × 10−8MUO22+. UO22+ was bound to humic acid by a continuum of sites with different strengths. The frequency distribution of these sites was log-normal. A Gaussian-Scatchard model was used to estimate the overall conditional stability constant for uranium concentrations of 5·25 × 10−8Mto 2·1 × 10−7M in the presence of 3·5 mg liter−1 humate (1·14 × 10−6M = φ). The estimates of the mean and standard deviation for the log of the stability constants were 6·5 and 0·8, respectively. When these mean and standard deviations were used to determine the mole-average number of binding sites at three points on the Gaussian distribution, the estimators of log-stability constants were found to be: K1 = 5·2, K2 = 6·5 andK3 = 7·7 with mole fractions of the total number of binding sites associated with each region of 0·21, 0·55 and 0·21, respectively. The thermodynamic, geochemical simulation model GEOCHEM and the three-component Gaussian-Scatchard estimates allowed accurate prediction of the relative proportion of UO22+ bound to humates for a soft water pond across the entire range of metal-ligand ratios studied. Approximately 22% of the UO22+ was predicted to be associated with dissolved organic carbon. 相似文献
14.
This study investigates the mortality effect of primary and secondary PM2.5 related to ship exhaust in the Sydney greater metropolitan region of Australia. A detailed inventory of ship exhaust emissions was used to model a) the 2010/11 concentration of ship-related PM2.5 across the region, and b) the reduction in PM2.5 concentration that would occur if ships used distillate fuel with a 0.1% sulfur content at berth or within 300 km of Sydney. The annual loss of life attributable to 2010/11 levels of ship-related PM2.5 and the improvement in survival associated with use of low-sulfur fuel were estimated from the modelled concentrations.In 2010/11, approximately 1.9% of the region-wide annual average population weighted-mean concentration of all natural and human-made PM2.5 was attributable to ship exhaust, and up to 9.4% at suburbs close to ports. An estimated 220 years of life were lost by people who died in 2010/11 as a result of ship exhaust-related exposure (95% CIβ: 140–290, where CIβ is the uncertainty in the concentration-response coefficient only). Use of 0.1% sulfur fuel at berth would reduce the population weighted-mean concentration of PM2.5 related to ship exhaust by 25% and result in a gain of 390 life-years over a twenty year period (95% CIβ: 260–520). Use of 0.1% sulfur fuel within 300 km of Sydney would reduce the concentration by 56% and result in a gain of 920 life-years over twenty years (95% CIβ: 600–1200).Ship exhaust is an important source of human exposure to PM2.5 in the Sydney greater metropolitan region. This assessment supports intervention to reduce ship emissions in the GMR. Local strategies to limit the sulfur content of fuel would reduce exposure and will become increasingly beneficial as the shipping industry expands. A requirement for use of 0.1% sulfur fuel by ships within 300 km of Sydney would provide more than twice the mortality benefit of a requirement for ships to use 0.1% sulfur fuel at berth. 相似文献
15.
Phelipe Manoel Oller Costa Marina Alessandra Gomes de Araújo Cristina Maria de Souza-Motta Elaine Malosso 《Environment, Development and Sustainability》2017,19(4):1189-1203
High litter inputs in agroforestry systems contribute to soil microbial activity, soil fertility and productivity. Considering that the cycling of organic matter is essential to the maintenance of physical–chemical and microbiological properties of the soil, the aims of this work were to estimate the production, accumulation and decomposition of litter, and assess soil microbial respiration in a complex multistrata agroforestry system located in the north-east of Brazil. This agroforestry system has three strata formed by forest and fruit trees and species of multiple uses. During 3 years (2011–2013), leaf litter was sampled monthly to account for litterfall and quarterly to account for litter accumulation. The rates of litter decomposition were estimated using the ratio produced-to-accumulated litter, and the correlation between litter fall and rainfall was calculated. Precipitation data were provided by the water and climate agency of Pernambuco (APAC). Soil samples (0–15 cm) were also taken quarterly, simultaneously with the litter accumulation samples, and soil microbial respiration was assessed using the capture, by a KOH solution, of the evolved CO2. The annual production of leaf litter was stable in the 3 years of study in this agroforestry system, and the monthly input of litter to the soil was influenced by rainfall, being higher in the dry seasons. The accumulated litter on the ground was constant, as was microbial activity (respiration) through time. The estimated litter decomposition rates were 1.49 (first year), 1.33 (second year) and 1.42 (third year), being considered rapid rates of decomposition. This guarantees (to the farmer) that this system is capable of maintaining soil fertility and eliminates the need for chemical fertilizers. 相似文献
16.
Philippe Calmon Yves Thiry Gregor Zibold Aino Rantavaara Sergei Fesenko 《Journal of environmental radioactivity》2009
Compared to agricultural lands, forests are complex ecosystems as they can involve diverse plant species associations, several vegetative strata (overstorey, shrubs, herbaceous and other annual plant layer) and multi-layered soil profiles (forest floor, hemi-organic and mineral layers). A high degree of variability is thus generally observed in radionuclide transfers and redistribution patterns in contaminated forests. In the long term, the soil compartment represents the major reservoir of radionuclides which can give rise to long-term plant and hence food contamination. For practical reasons, the contamination of various specific forest products has commonly been quantified using the aggregated transfer factor (Tag in m2 kg−1) which integrates various environmental parameters including soil and plant type, root distribution as well as nature and vertical distribution of the deposits. Long lasting availability of some radionuclides was shown to be the source of much higher transfer in forest ecosystems than in agricultural lands. This study aimed at reviewing the most relevant quantitative information on radionuclide transfers to forest biota including trees, understorey vegetation, mushrooms, berries and game animals. For both radiocaesium and radiostrontium in trees, the order of magnitude of mean Tag values was 10−3 m2 kg−1 (dry weight). Tree foliage was usually 2–12 times more contaminated than trunk wood. Maximum contamination of tree components with radiocaesium was associated with (semi-)hydromorphic areas with thick humus layers. The transfer of radionuclides to mushrooms and berries is high, in comparison with foodstuffs grown in agricultural systems. Concerning caesium uptake by mushrooms, the transfer is characterized by a very large variability of Tag, from 10−3 to 101 m2 kg−1 (dry weight). For berries, typical values are around 0.01–0.1 m2 kg−1 (dry weight). Transfer of radioactive caesium to game animals and reindeer and the rate of activity reduction, quantified as an ecological half-life, reflect the soil and pasture conditions at individual locations. Forests in temperate and boreal regions differ with respect to soil type and vegetation, and a faster decline of muscle activity concentrations in deer occurs in the temperate zone. However, in wild boar the caesium activity concentration shows no decline because of its special feeding habits. In the late phase, i.e. at least a few months since the external radionuclide contamination on feed plants has been removed, a Tag value of 0.01 m2 kg−1 (fresh weight) is common for 137Cs in the muscles of adult moose and terrestrial birds living in boreal forests, and 0.03 m2 kg−1 (fresh weight) for arctic hare. Radiocaesium concentrations in reindeer muscle in winter may exceed the summer content by a factor of more than two, the mean Tag values for winter ranging from 0.02 to 0.8 m2 kg−1 (fresh weight), and in summer from 0.04 to 0.4 m2 kg−1. The highest values are found in the year of initial contamination, followed by a gradual reduction. In waterfowl a relatively fast decline in uptake of 137Cs has been found, with Tag values changing from 0.01 to 0.002 m2 kg−1 (fresh weight) in the three years after the contaminating event, the rate being determined by the dynamics of 137Cs in aquatic ecosystems. 相似文献
17.
The Almaraz nuclear power plant (Spain) uses the water of Arrocampo reservoir for cooling, and consequently raises the radioactive levels of the aquatic ecosystem of this reservoir. From July 2002 to June 2005, monthly samples of surface water, bulrushes (Typha latifolia) and carp (Cyprinus carpio) were collected from this reservoir. They were analyzed to determine the temporal evolution of the levels of 3H in surface water and of its transfer from the surface water to free-water in the tissues (TFWT) of the aforementioned two organisms. The tritium levels in the surface water oscillate with a biannual period, with their values in the study period ranging between 53 and 433 Bq/L. The incorporation of tritium to bulrushes and carp was fairly similar, the respective mean concentration factors being 0.74 and 0.8 (unitless, as Bq/L tissue water per Bq/L reservoir water). The temporal evolution of the levels fairly closely followed that observed for the surface water tritium, although detailed analysis showed the dominant periodicity for the bulrushes to be annual. This difference reflects the influence on the incorporation of tritium to bulrushes of diverse environmental and metabolic factors, especially evapotranspiration and the seasonal growth of this plant. 相似文献
18.
Per- and poly-fluorinated compounds (PFCs), which include perfluorinated carboxylates (PFCAs) and sulfonates (PFSAs) and various precursors, are used in a wide variety of industrial, commercial and domestic products. This includes aqueous film forming foam (AFFF), which is used by military and commercial airports as fire suppressants. In a preliminary assessment prior to this study, very high concentrations (> 1 ppm wet weight) of the PFSA, perfluorooctane sulfonate (PFOS), were discovered in the plasma of snapping turtles (Chelydra serpentina) collected in 2008 from Lake Niapenco in southern Ontario, Canada. We presently report on a suite of C6 to C15 PFCAs, C4, C6, C8 and C10 PFSAs, several PFC precursors (e.g. perfluorooctane sulfonamide, PFOSA), and a cyclic perfluorinated acid used in aircraft hydraulic fluid, perfluoroethylcyclohexane sulfonate (PFECHS) in surface water from the Welland River and Lake Niapenco, downstream of the John C. Munro International Airport, Hamilton, Ontario, Canada. Amphipods, shrimp, and water were sampled from the Welland River and Lake Niapenco, as well as local references. The same suite of PFCs in turtle plasma from Lake Niapenco was compared to those from other southern Ontario sites. PFOS dominated the sum PFCs in all substrates (e.g., > 99% in plasma of turtles downstream the Hamilton Airport, and 72.1 to 94.1% at all other sites). PFOS averaged 2223 (± 247.1 SE) ng/g in turtle plasma from Lake Niapenco, and ranged from 9.0 to 171.4 elsewhere. Mean PFOS in amphipods and in water were 518.1 (± 83.8) ng/g and 130.3 (± 43.6) ng/L downstream of the airport, and 19.1 (± 2.7) ng/g and 6.8 (± 0.5) ng/L at reference sites, respectively. Concentrations of selected PFCs declined with distance downstream from the airport. Although there was no known spill event or publicly reported use of AFFF associated with a fire event at the Hamilton airport, the airport is a likely major source of PFC contamination in the Welland River. 相似文献
19.
Fertilization with 2.5 t/ha limestone: (83% CaCO3, 8% MgO, 6% K2O, 3% P2O5) reduces the 137Cs transfer from spruce forest soil into plants like fern (Dryopteris carthusiana) and blackberry (Rubus fruticosus) by a factor of 2–5 during at least 11 years as measured by the aggregated transfer factor Tag. In 1997 and 2006 these results were confirmed by additional measurements of the 137Cs transfer factor TF, related to the root zone (Oh horizon), which were explained by the selective sorption of 137Cs in the root zone by measurements of the Radiocaesium Interception Potential (RIP) in fertilized (RIP > 179 meq/kg) and non-fertilized soils (RIP < 74 meq/kg). 相似文献
20.
Azita Farashi 《Russian Journal of Ecology》2018,49(5):449-455
Many factors such as human activities threat brown bears (Ursus arctos) in Southern Asia, and limit it to small populations in remote and rocky mountainous regions. Brown bears are generally studied in North America and Europe, but there is little information about its conditions and requirements for survival in Asia. During the recent years, brown bear populations in Iran have decreased sharply. Therefore, they are now officially listed as a threatened species in local scale. Therefore, we tried to recognize brown bear habitat relationships in northern Iran using species distribution model (SDM). Maxent method was applied using multiscale approach to predict suitable habitats and habitat relationships of the species. Our results revealed that the predictive ability of environment variables and species distribution maps varied across scales strongly. Also, our findings showed that identifying a proper scale is important issue to improve habitat modeling accuracy. Only 17% of the protected areas was found suitable for brown bear and divided to 5.1% poor, 8.8% suitable, and 3.1% high-quality habitat. Consequently, it is suggested that the protected area of northern Iran reconsiders with interventions aimed at maintaining suitable habitats of brown bear. 相似文献