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721.
Heavy metal accumulation in soil poses serious environmental and health risks, as metals are carried with eroded soils. In this study, 17 different soil erosion and sediment control products were investigated for their effectiveness in controlling transport of particulate heavy metals (Cu, Zn, Pb, Cd). Among the treatments investigated, wood mulch and tackifiers were found to be the most effective in reducing total suspended solids (TSS) and total heavy metal losses. They reduced TSS to an undetectable level during short-term simulation tests. Paper mulch was the only treatment that had no significant reduction in both total metal loss and TSS. Fiber rolls, silt fences, and gravel bags were effective in reducing sediment loss. Although the netting/blanket treatments were not effective in reducing total metal discharge, they significantly reduced sediment loss compared with the control.  相似文献   
722.
Simulating Land-Cover Change in Montane Mainland Southeast Asia   总被引:6,自引:0,他引:6  
We used the conversion of land use and its effects (CLUE-s) model to simulate scenarios of land-cover change in Montane mainland southeast Asia (MMSEA), a region in the midst of transformation due to rapid intensification of agriculture and expansion of regional trade markets. Simulated changes affected approximately 10 % of the MMSEA landscape between 2001 and 2025 and 16 % between 2001 and 2050. Roughly 9 % of the current vegetation, which consists of native species of trees, shrubs, and grasses, is projected to be replaced by tree plantations, tea, and other evergreen shrubs during the 50 years period. Importantly, 4 % of this transition is expected to be due to the expansion of rubber (Hevea brasiliensis), a tree plantation crop that may have important implications for local-to-regional scale hydrology because of its potentially high water consumption in the dry season.  相似文献   
723.
Federal land managers are faced with the task of balancing multiple uses and goals when making decisions about land use and the activities that occur on public lands. Though climate change is now well recognized by federal agencies and their local land and resource managers, it is not yet clear how issues related to climate change will be incorporated into on-the-ground decision making within the framework of multiple use objectives. We conducted a case study of a federal land management agency field office, the San Juan Public Lands Center in Durango, CO, U.S.A., to understand from their perspective how decisions are currently made, and how climate change and carbon management are being factored into decision making. We evaluated three major management sectors in which climate change or carbon management may intersect other use goals: forests, biofuels, and grazing. While land managers are aware of climate change and eager to understand more about how it might affect land resources, the incorporation of climate change considerations into everyday decision making is currently quite limited. Climate change is therefore on the radar screen, but remains a lower priority than other issues. To assist the office in making decisions that are based on sound scientific information, further research is needed into how management activities influence carbon storage and resilience of the landscape under climate change.  相似文献   
724.
This paper assesses local biodiversity monitoring methods practiced in the Tonle Sap Lake of Cambodia. For the assessment we used the following criteria: methodological rigor, perceived cost, ease of use (user friendliness), compatibility with existing activities, and effectiveness of intervention. Constraints and opportunities for execution of the methods were also considered. Information was collected by use of: (1) key informant interview, (2) focus group discussion, and (3) researcher's observation. The monitoring methods for fish, birds, reptiles, mammals and vegetation practiced in the research area have their unique characteristics of generating data on biodiversity and biological resources. Most of the methods, however, serve the purpose of monitoring biological resources rather than biodiversity. There is potential that the information gained through local monitoring methods can provide input for long-term management and strategic planning. In order to realize this potential, the local monitoring methods should be better integrated with each other, adjusted to existing norms and regulations, and institutionalized within community-based organization structures.  相似文献   
725.
Barriers and bridges to implement policies about sustainable development and sustainability commonly depend on the past development of social–ecological systems. Production of metals required integration of use of ore, streams for energy, and wood for bioenergy and construction, as well as of multiple societal actors. Focusing on the Swedish Bergslagen region as a case study we (1) describe the phases of natural resource use triggered by metallurgy, (2) the location and spatial extent of 22 definitions of Bergslagen divided into four zones as a proxy of cumulative pressure on landscapes, and (3) analyze the consequences for natural capital and society. We found clear gradients in industrial activity, stream alteration, and amount of natural forest from the core to the periphery of Bergslagen. Additionally, the legacy of top-down governance is linked to today’s poorly diversified business sector and thus municipal vulnerability. Comparing the Bergslagen case study with other similar regions in Russia and Germany, we discuss the usefulness of multiple case studies.  相似文献   
726.
Panax notoginseng (Burk.) F.H. Chen, a rare traditional Chinese medicinal herb, is a widely used phytomedicine used all over the world. In recent years, the arsenic contamination of the herb and its relative products becomes a serious problem due to elevated soil As concentration. This study aimed to evaluate the effects of different types and dosages of amendments on As stabilization in soil and its uptake by P. notoginseng. Results showed that comparing to control treatment, the As concentrations of P. notoginseng declined by 49–63%, 43–61% and 52–66% in 0.25% zero-valent iron (Fe(0)), 0.5% bauxite residue, and 1% zeolite treatment, respectively; whereas the biomasses were elevated by 62–116%, 45–152% and 114–265%, respectively. The As(III) proportions of P. notoginseng increased by 8%, 9%, and 8%, and the transfer factors of As from root to shoot increased by 37%, 42% and 84% in the optimal treatments of Fe(0), bauxite residue, and zeolite. For soil As, all the three amendments could transform the non-specifically adsorbed As fraction to hydrous oxides Fe/Al fractions (by Fe(0) and red mud) or specifically adsorbed As fraction (by zeolite), therefore reduced the bioavailability of soil As. With a comprehensive consideration of stabilization efficiency, plant growth, environmental influence, and cost, Fe(0) appeared to be the best amendment, and zeolite could also be a good choice. In conclusion, this study was of significance in developing As contamination control in P. notoginseng planting areas, and even other areas for medicinal herb growing.  相似文献   
727.
Two compounds, 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO) are the main ingredients in a suite of explosive formulations that are being, or soon will be, fielded at military training ranges. We aim to understand the dissolution characteristics of DNAN and NTO and three insensitive muntions (IM) formulations that contain them. This information is needed to accurately predict the environmental fate of IM constituents, some of which may be toxic to people and the environment. We used Raman spectroscopy to identify the different constituents in the IM formulations and micro computed tomography to image their three-dimensional structure. These are the first three-dimensional images of detonated explosive particles.  相似文献   
728.
Organochlorine contamination in the Mediterranean coastal environment of Egypt was assessed based on 26 surface sediments samples collected from several locations on the Egyptian coast, including harbors, coastal lakes, bays, and estuaries. The distribution and potential ecological risk of contaminants is described. Organochlorine compounds (OCs) were widely distributed in the coastal environment of Egypt. Concentrations of PCBs, DDTs, and chloropyrifos ranged from 0.29 to 377 ng g−1 dw, 0.07 to 81.5 ng g−1 dw, and below the detection limit (DL) to 288 ng g−1 dw, respectively. Other organochlorinated pesticides (OCP) studied were 1–2 orders of magnitude lower. OCP and PCBs had higher concentrations at Burullus Lake, Abu Qir Bay, Alexandria Eastern Harbor, and El Max Bay compared to other sites. OCP and PCB contamination is higher in the vicinity of possible input sources such as shipping, industrial activities and urban areas. PCB congener profiles indicated they were derived from more than one commercially available mixture. The ratios of commercial chlordane and heptachlor metabolites indicate historical usage; however, DDT and HCHs inputs at several locations appear to be from recent usage. The concentrations of PCBs and DDTs are similar to those observed in sediments from coastal areas of the Mediterranean Sea. Ecotoxicological risk from DDTs and PCBs is greatest in Abu Qir Bay, Alexandria Harbor, and El-Max Bay.  相似文献   
729.
In this study, an analytical methodology was developed for the determination of psycho-active drugs in the treated effluent of the University Hospital at the Federal University of Santa Maria, RS – Brazil. Samples were collected from point A (Emergency) and point B (General effluent). The adopted methodology included a pre-concentration procedure involving the use of solid phase extraction and determination by liquid chromatography coupled to mass spectrometry. The limit of detection for bromazepam and lorazepam was 4.9 ± 1.0 ng L−1 and, for carbamazepine, clonazepam and diazepam was 6.1 ± 1.5 ng L−1. The limit of quantification was 30.0 ± 1.1 ng L−1, for bromazepam, clonazepam and lorazepam; for carbamazepine was 50.0 ± 1.8 ng L−1 and was 40.0 ± 1.0 ng L−1 for diazepam. The mean concentrations in the Emergency and General effluent treated currents were as follows: for bromazepam, 195 ± 6 ng L−1 and 137 ± 7 ng L−1; for carbamazepine, 590 ± 6 ng L−1 and 461 ± 10 ng L−1; for diazepam, 645 ± 1 ng L−1 and 571 ± 10 ng L−1; for lorazepam, 96 ± 7 ng L−1 and 42 ± 4 ng L−1; and for clonazepam, 134 ± 10 ng L−1 and 57 ± 10 ng L−1. A preliminary risk assessment was conducted: carbamazepine and diazepam require considerable attention owing to their environmental toxicity. The occurrence of these psychoactive-drugs and the environmental risks that they pose demonstrated the need for a more efficient treatment system. As far we are aware, there have been no comparable studies to this on the hazards of hospital effluents in Brazil, and very few that have carried out a risk assessment of psycho-active drugs in hospital effluent in general.  相似文献   
730.
Previous attempts to measure heavy metals in air are discussed with particular reference to lead. A polarographic method was developed for lead in air samples taken on glass fiber sheet. Using this method, the distribution of lead across the glass fiber sheet was investigated, and within experimental error, found to be uniform. Air samples from 18 Ontario cities, previously analyzed for benzo [a]pyrene content were analyzed.  相似文献   
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