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1.
Temporal changes in the amounts of trace elements (As, Co, Cu, Mn, Ni, Pb, and Zn) and their correlations with temporal changes in charcoal abundance in age-dated sediments collected from Lake Thompson in Patagonia, Chile, attest to the substantial pyrogenic remobilization of contaminants that occurred in Patagonia during the mid-1900s. This remobilization was concurrent with the extensive slash and burn period in the region during that period. The changes in concentrations of Co, Cu, and Ni in relation to charcoal abundance in the lacustrine sediments over time were small compared to those of As, Mn, Pb, and Zn. However, the relatively low enrichment factors of all those trace elements, normalized to Fe, indicate that they were predominantly derived from local, natural sources impacted by fires rather than industrial sources. The primarily local source of Pb in the sediments was corroborated by the temporal consistency of its isotopic ratios ( 206Pb/ 207Pb: 208Pb/ 206Pb), which were similar to previously reported values for natural lead in Central and Southern Chile. However, the pyrogenic remobilization of both natural and industrial trace elements by forest fires in Chile and elsewhere is expected to rise as a consequence of climate change, which is projected to increase both the frequency and intensity of forest fires on a global scale. 相似文献
4.
River deltas all over the world are sinking beneath sea-level rise, causing significant threats to natural and social systems. This is due to the combined effects of anthropogenic changes to sediment supply and river flow, subsidence, and sea-level rise, posing an immediate threat to the 500–1,000 million residents, many in megacities that live on deltaic coasts. The Mississippi River Deltaic Plain (MRDP) provides examples for many of the functions and feedbacks, regarding how human river management has impacted source-sink processes in coastal deltaic basins, resulting in human settlements more at risk to coastal storms. The survival of human settlement on the MRDP is arguably coupled to a shifting mass balance between a deltaic landscape occupied by either land built by the Mississippi River or water occupied by the Gulf of Mexico. We developed an approach to compare 50 % L:W isopleths ( L:W is ratio of land to water) across the Atchafalaya and Terrebonne Basins to test landscape behavior over the last six decades to measure delta instability in coastal deltaic basins as a function of reduced sediment supply from river flooding. The Atchafalaya Basin, with continued sediment delivery, compared to Terrebonne Basin, with reduced river inputs, allow us to test assumptions of how coastal deltaic basins respond to river management over the last 75 years by analyzing landward migration rate of 50 % L:W isopleths between 1932 and 2010. The average landward migration for Terrebonne Basin was nearly 17,000 m (17 km) compared to only 22 m in Atchafalaya Basin over the last 78 years ( p < 0.001), resulting in migration rates of 218 m/year (0.22 km/year) and <0.5 m/year, respectively. In addition, freshwater vegetation expanded in Atchafalaya Basin since 1949 compared to migration of intermediate and brackish marshes landward in the Terrebonne Basin. Changes in salt marsh vegetation patterns were very distinct in these two basins with gain of 25 % in the Terrebonne Basin compared to 90 % decrease in the Atchafalaya Basin since 1949. These shifts in vegetation types as L:W ratio decreases with reduced sediment input and increase in salinity also coincide with an increase in wind fetch in Terrebonne Bay. In the upper Terrebonne Bay, where the largest landward migration of the 50 % L:W ratio isopleth occurred, we estimate that the wave power has increased by 50–100 % from 1932 to 2010, as the bathymetric and topographic conditions changed, and increase in maximum storm-surge height also increased owing to the landward migration of the L:W ratio isopleth. We argue that this balance of land relative to water in this delta provides a much clearer understanding of increased flood risk from tropical cyclones rather than just estimates of areal land loss. We describe how coastal deltaic basins of the MRDP can be used as experimental landscapes to provide insights into how varying degrees of sediment delivery to coastal deltaic floodplains change flooding risks of a sinking delta using landward migrations of 50 % L:W isopleths. The nonlinear response of migrating L:W isopleths as wind fetch increases is a critical feedback effect that should influence human river-management decisions in deltaic coast. Changes in land area alone do not capture how corresponding landscape degradation and increased water area can lead to exponential increase in flood risk to human populations in low-lying coastal regions. Reduced land formation in coastal deltaic basins (measured by changes in the land:water ratio) can contribute significantly to increasing flood risks by removing the negative feedback of wetlands on wave and storm-surge that occur during extreme weather events. Increased flood risks will promote population migration as human risks associated with living in a deltaic landscape increase, as land is submerged and coastal inundation threats rise. These system linkages in dynamic deltaic coasts define a balance of river management and human settlement dependent on a certain level of land area within coastal deltaic basins ( L). 相似文献
6.
Environment, Development and Sustainability - For a long time, air pollution caused by unreasonable urban spatial structure and excessive urban sprawl has been a prominent environmental problem in... 相似文献
7.
On the basis of studies on the ecology of boreal bat species in the Southern Urals (1997–2004), the first classification of their summer habitats has been made. It has been shown that spatial segregation of sex groups into areas of two types, designated wintering and breeding zones, takes place in populations in the period of offspring rearing. In females, seasonal migrations are guided by imprinting on sites providing sufficient food for offspring rearing and on wintering sites. In males, imprinting on wintering sites alone is observed. 相似文献
8.
Chlorinated paraffins (CPs) are large production volume chemicals used in a wide variety of commercial applications. They are ubiquitous in the environment and humans. Human exposure via the indoor environment has, however, been barely investigated. In the present study 44 indoor air and six dust samples from apartments in Stockholm, Sweden, were analyzed for CPs, and indoor air concentrations are reported for the first time. The sumCP concentration (short chain CPs (SCCPs) and medium chain CPs (MCCPs)) in air ranged from <5-210 ng m(-3) as quantified by gas chromatography coupled to electron ionization tandem mass spectrometry (GC/EI-MS/MS). Congener group patterns were studied using GC with electron capture negative ionization MS (GC/ECNI-MS). The air samples were dominated by the more volatile SCCPs compared to MCCPs. SumCPs were quantified by GC/EI-MS/MS in the dust samples at low μg g(-1) levels, with a chromatographic pattern suggesting the prevalence of longer chain CPs compared to air. The median exposure to sumCPs via the indoor environment was estimated to be ~1 μg day(-1) for both adults and toddlers. Adult exposure was dominated by inhalation, while dust ingestion was suggested to be more important for toddlers. Comparing these results to literature data on dietary intake indicates that human exposure to CPs from the indoor environment is not negligible. 相似文献
9.
Following the Chernobyl accident, 137Cs contamination levels of wild boar in some districts of Southern Germany are still exceeding thousands of Bq kg −1. While the long term 137Cs concentration in forest plants, mushrooms, and roe deer meat has decreased significantly, for wild boar it has remained constant during the last decade. Between 1998 and 2008, we analysed the muscle meat of 656 wild boars shot in the district (“Landkreis”) Ravensburg. The 137Cs activity concentration showed considerable variability from less than 5 up to 8266 Bq kg −1 and it followed a seasonal pattern, which is attributed to changes in dietary habits, fodder availability, meteorological conditions and specific behaviour of 137Cs in wild boar organism. Tag values for wild boars from the district Ravensburg varied from 0.008 to 0.062 m 2 kg −1 during 2000–2008. 相似文献
10.
Regional Environmental Change - This article describes the design of a new model-based assessment framework to identify and analyse possible future trajectories of agricultural development and... 相似文献
11.
Ecological scales proposed by H. Ellenberg, E. Landolt, and D.N. Tsyganov have been used to evaluate the roles of three ecological factors—elevation above sea level, soil moisture, and soil nitrogen—in determining the composition of forest communities in the Southern Ural region. The results obtained with all these scales are similar, which indicates that any of them can serve the purpose. 相似文献
12.
Particulate matter (PM) is a key indicator of air pollution brought into the air by a variety of natural and human activities. As it can be suspended over long time and travel over long distances in the atmosphere, it can cause a wide range of diseases that lead to a significant reduction of human life. The size of particles has been directly linked to their potential for causing health problems. Small particles of concern include “inhalable coarse particles” with a diameter of 2.5 to 10 μm and “fine particles” smaller than 2.5 μm in diameter. As the source–effect relationship of PM remains unclear, it is not easy to define such effects from individual sources such as long-range transport of pollution. Because of the potent role of PM and its associated pollutants, detailed knowledge of their human health impacts is of primary importance. This paper summarizes the basic evidence on the health effects of particulate matter. An in-depth analysis is provided to address the implications for policy-makers so that more stringent strategies can be implemented to reduce air pollution and its health effects. 相似文献
13.
Increased economic development and industrialization put strain on environment, hence causing pollution and destroying ecosystem. Generally, many different factors affect the environment. These factors include GHG emissions, deforestation, and others. These are all related to human activities on Earth. Other factors that affect environment include population, consumption patterns, and changing life styles of people due to increased income. This study involves the comparison analysis of Pakistan and China on the basis of environmental impact caused by some major driving factors. China is the second largest CO 2 emitter in the world with a population of 1.37 billion in 2016 and the second largest economy in the world. Pakistan is ranked as 40th on the basis of nominal GDP. Both the countries observed noticeable growth in economic development for over 55 years, i.e. 1960–2016. This study identifies how population, affluence, consumption, and emissions as the major factors affect environmental pollution and use ImPACT equation, or I = PACT, to calculate the environmental impact and to determine which factors affect the environment the most. The study suggests that the people of both China and Pakistan have experienced increased income for the past 50 years and this increase has led to the changes in their lifestyles, from suitable clothing and quality food to comfortable living and increased energy consumption, thus affecting environment. 相似文献
14.
Small island states around the world are among the areas most vulnerable to climate change and sea level rise. In this paper, we present results from an innovative methodology for a quantitative assessment of multiple hazards on coastal risks, driven by different hydro-meteorological events, and including the effects of climate change. Moreover, we take an additional step by including in the methodology the option to assess and compare the effectiveness of possible disaster risk reduction measures. The methodology is applied to a real case study at the island of Ebeye (the Republic of the Marshall Islands). An example is provided in which a rock revetment is implemented as a risk reduction measure for the island. Results show that yearly expected damages may increase, by the end of the century, by a factor of three to four, depending on the sea level rise scenario considered, while the number of yearly affected people may double. Putting a cap on the temperature increase (e.g. 1.5 vs. 2 °C) according to the Paris Agreement may reduce damages and number of affected people by about 20 and 15%, respectively. However, impacts for same warming levels can vary substantially among different emission scenarios. Disaster risk reduction measures can be useful for mitigating risks in current and future situations but should be incorporated within long-term adaptive planning for these islands. 相似文献
15.
The relationship between media and the construction of environmental policy has been studied acutely in the Global North. However, less attention has been paid to deeper cultural symbols displayed in public policy discussions in the Global South. Through qualitative examination of 100 letters to the editor (LTE) of the Chilean newspaper, El Mercurio, this study examined the imaginaries in the public discussion of the Native Forest Policy in Chile. Although such a discussion was often framed as a technical debate, the letters to El Mercurio were embedded within Catholic imaginaries, condensed into two main sets. The first one constructed forests as endangered due to human action and called for immediate protection, contending that humans shall not destroy God's creation. The second set depicted a degraded forest in need of rational management to satisfy the needs of God's children. This study suggests that, in a mediated public discussion, religion might play an important role in communicating environmental issues. This work contributes to our understanding of environmental imaginaries and discourses in the context of environmental controversies, to the understanding of the functions of the LTE, and to the social construction of forest policy in recent post-autocratic regimes. 相似文献
16.
Regional Environmental Change - Alien invasive species cause significant impacts on ecosystems and economies, but the impacts on human well-being and livelihoods are less well known. Negative... 相似文献
17.
BackgroundFew data exist in Latin America concerning the association between organophosphate (OP) urinary metabolites and the consumption of fruits and vegetables and other exposure risk variables in schoolchildren. MethodsWe collected samples of urine from 190 Chilean children aged 6–12 years, fruits and vegetables, water and soil from schools and homes, and sociodemographic data through a questionnaire. We measured urinary dialkylphosphate (DAP) OP metabolites and OP pesticide residues in food consumed by these 190 children during two seasons: December 2010 (summer) and May 2011 (fall). We analyzed the relationship between urinary DAP concentrations and pesticide residues in food, home pesticide use, and residential location. ResultsDiethylalkylphosphates (DEAP) and dimethylalkylphosphates (DMAP) were detected in urine in 76% and 27% of the samples, respectively. Factors associated with urinary DEAP included chlorpyrifos in consumed fruits ( p < 0.0001), urinary creatinine ( p < 0.0001), rural residence ( p = 0.02) and age less than 9 years ( p = 0.004). Factors associated with urinary DMAP included the presence of phosmet residues in fruits ( p < 0.0001), close proximity to a farm ( p = 0.002), home fenitrothion use ( p = 0.009), and season ( p < 0.0001). ConclusionsUrinary DAP levels in Chilean school children were high compared to previously reported studies. The presence of chlorpyrifos and phosmet residues in fruits was the major factor predicting urinary DAP metabolite concentrations in children. 相似文献
18.
Climate change is projected to influence the genetic resources of plant species. Recent research has examined genetic diversity patterns under current climate conditions, with little attention to the future genetic consequences for species. In this study, we combined ecological niche modeling and population genetic approaches to project future changes in genetic diversity using plastid and nuclear DNA and reconstructed distribution patterns of three circumboreal plants (Chamaedaphne calyculata, Linnaea borealis ssp. borealis, and Pedicularis sceptrum-carolinum ssp. sceptrum-carolinum) in the last glacial maximum. We found that circumboreal plants could potentially lose their geographic ranges in the future (2070; 35–52% in RCP 4.5 (representative concentration pathways), 37–53% in RCP 6.0, and 56–69% in RCP 8.5), only slightly compensated by a predicted range gain of 18–33% (across the three RCPs). It is expected that future genetic diversity level could remain similar or lower than the present level. On the other hand, the homogeneity of the genetic background—a lack of admixture and domination of one gene pool in most populations of C. calyculata and L. borealis ssp. borealis—was predicted to become more pronounced in the future. Combining the paleoecological niche modeling and genetic data revealed, more precisely, the climate refugia for circumboreal plants in the Alps, central Asia, Beringia, and southern North America and the macrorefugia more restricted to the northern part of Eurasia and North America, reaching the arctic zone. 相似文献
19.
The Limpopo River Basin is underlain by an alluvial aquifer along the main river stem and fractured water-bearing units in tributary catchments. Notwithstanding that development priorities in parts of the basin in South Africa have historically preferred surface water sources for irrigation and domestic supply, water resources auditing suggests that groundwater presents the only viable alternative source of cost-effective supply to meet future requirements. However, while aquifer yields are favourable in places, averaging 16.7 l/s for main-stem alluvium, groundwater is already extensively used. Between 1995 and 2002, total groundwater use in the area rose by almost 40%, increasing from 98 to 136 million m 3 per year. In all catchments, groundwater use grew by varying proportions, reaching a rather high 200% in the Mogalakwena catchment. In the particular case of commercial irrigation, over-exploitation of groundwater has been recorded in a number of places, especially in the northwest where drawdowns of more than 50 m have resulted from decades of intense agricultural water use. Although groundwater use for mining is still low at 4% of total usage in the study area, the region is currently witnessing a surge in mining operations, and a significant growth in water requirements is envisaged for mining development. Further, domestic water supply to the predominantly rural dwellers in the area is relatively low, even in terms of meeting the basic need of 25 l/day per person, underscoring the fact that groundwater will remain a critical source of community drinking water in the foreseeable future. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
20.
The results of long-term studies (1973–1982) have been used to analyze specific features in the distribution of larid bird colonies in the Selenga River delta over an 11-year climate cycle. It has been shown that the spatial distribution of these birds has distinct patterns in years with different water levels (high, medium, or low) in the delta and is based on preference for certain nesting biotopes, which is well manifested in all species studied and depends on their ecological niches. The main factors determining the distribution of birds over the study area include water level, terrain topography, and locations of major aggregations of food organisms. 相似文献
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