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1.
Many communities along coastlines and riverbanks are threatened by water erosion and hence an accurate model to predict erosion events is needed in order to plan mitigation strategies. Such models need to rely on readily available meteorological data that may or may not be correlated with the occurrence of erosion events. Computing these correlations requires a quantified index that reports the magnitude of erosion events over time. This study introduces a method to create erosion indices using affordable consumer grade digital cameras. It is able to detect and quantify erosion using an image series obtained from just one such camera by segmenting each images instance into equally sized squares that can be preprocessed and analyzed separately. This approach isolates each image segment from noise and temporary disturbances that frequently occur throughout images taken with low cost cameras. In this fashion, noise may either be addressed locally or simply ignored if it is too extreme. After preprocessing, comparison of subsequent segments yields change matrices that form the basis for segment-specific erosion indices that are later combined into a composite value for the entire image instance. Whenever a segment instance is unavailable or unusable, the algorithm attempts to use neighboring instances whenever possible. When tested against human observation of erosion events during a 6 week period, the resulting index achieves a true positive rate of 67% while producing only a small number of false positives. Finally, the index is validated by significant correlation with various meteorological data streams.  相似文献   

2.
The speciation of nickel is of the highest importance for the definition of lists of substances for regulatory activity in terms of prevention, regarding possible cancer risk. A review is made of the different attitudes of outstanding administrations in front of nickel speciation. Some of them show a maximum of care in chemical definition, others reflect a lack of scientific rigor leading to generic classifications, more or less abusive. The great complexity of the chemistry and physicochemistry of nickel imposes the “two‐level speciation concept” (chemical and physicochemical), at least for compliance with the “Good Laboratory Practice” as far as experimental toxicology is concerned. Recommendations are exposed for the attention of toxicologists and regulators who have been for some years now extremely solicited for prevention aims.  相似文献   

3.
4.
The changes promoted by treatment of a highly polluted soil with sulphuric acid or calcium hydroxide for changing its pH value are studied by controlling physical properties (particle size, TGA and DTA curves), evolution of metal species (exchangeable, as carbonates, related to Fe‐Mn oxides, linked to organic matter and residual) and metal uptake by plant cultures. Metal contents were determined, after wet digestion with HF—HNO3—HC1O4 when necessary, by AAS (Ca, Mg, Cu, Pb, Mn, Fe, Zn) or emission (Na, K). The treatment of soil with successive amounts of sulphuric leads to changes in particle size, hydration properties and exothermic peak for organic matter combustion. Very small changes were, however, detected in the alkaline treatment of soil. Soil treatments do not have practical influence on speciation of some metals (Na, K, Mg, Pb, Mn, Fe), but the intensity of the acid treatment leads to both an increase in the Cu extraction and a decrease in the Ca solubilization, probably through gypsum formation. In the case of zinc a maximum solubility in the middle of the range of acid treatment was observed. The comparison among extractants shows solubilities high for two pollutants (Pb, Cu), associated mainly to Fe—Mn oxides and organic matter, and low for two macrocomponents (Fe, K). The rest of metals, basically present in soil as carbonates or oxides, have intermediate extractions. Pot cultures weights depended mainly on both the treatment of soil (poor development in the more acid sample and drainage difficulties in the rest of acid treatments) and the situation (very low weights in laboratory runs as compared with outside), but the irrigation with water or a diluted sulphuric acid solution (at pH = 4.0) did not produce significant weight changes. Tendencies to increase plant pollution were observed for smaller soil pH, acid irrigation and probably for outside cultures, due to uptake by leaves.  相似文献   

5.
In the winter of 2006/2007 approximately 200,000 m3 of high quality sand from the dredging of the local marina were placed at the ocean-side beaches in the vicinity of a tourism development in Tróia, Portugal. The beach-quality sediment provided a source of “sand of opportunity” which was used to increase the dry-beach width of the highly used coastal stretch. The sediment was placed along approximately 600 m of shoreline and a monitoring program has since being carried out twice a year. High-resolution topographic surveys and sediment analysis are being conducted to evaluate the performance and response of the fill to the local forcing factors and ultimately to evaluate the effectiveness of the fill project. Two years after the nourishment, the sediment has been distributed both cross-shore and alongshore. The pre-nourishment beach slope was attained and the new shoreline has acquired a natural shape. Berm width increased by a maximum of 100 m, and a set of new dune ridges has developed, due to sand accumulation promoted by the settlement of vegetation. In conclusion, 2 years after its completion, the beach nourishment in Tróia can be viewed as a successful project in which the beneficial use of dredged material resulted in: 1) area for increased dune field growth and development, 2) enhancement of potential shorebird nesting areas and habitat, and 3) increased area for recreation purposes.  相似文献   

6.
The environmental decision-maker is aware of the increasing difficulties in finding sufficient financial resources for nature conservation. So he must focus his attention on ecological situations that more than the others merit considering and defending because of elevated value but also because of risk for their intrinsic characteristics and for human pressure acting on them. Usually an ecological scientist focuses his attention on the natural patches of the landscape, analyzing their peculiar ecological traits forgetting that, even if we want to protect some environmental critical situations, this can be done only moving to the administrative partition of the territory since the central and local environmental stakeholders have primary interest in providing funds to those involved in those critical situations. The present work shows a methodological approach, consisting of a set of statistical and geoinformational tools, considering both ecological and socio-demographical indicators. The goal is not simply to give some general guidelines for environmental policies to the involved stakeholders but focuses more on finding out which administrative local partitions in a study area are more worthy to receive urgently the priority funds for biodiversity protection to face critical environmental situations often due to a combination of intrinsic ecological parameters and external human pressure ones. Obtaining results that cover 5% of the Communes involved in the area seems to be a realistic result that a decision-maker can support and fund. Methodologically and geospatial data analytically, the investigation offers interesting challenges for surveillance geoinformatics of hotspot detection and prioritization, because of the presence of multiple hotspots and multiple sets of multiple indicators.  相似文献   

7.
Spatial and temporal distributions of water quality using multivariate statistical techniques for the evaluation of nutrients (NO2-N, NO3-N, NH4-N, PO4-P, SiO4-Si, total N, total P) in relation to some physico-chemical features (DO, BOD, TSS, TDS, SO42−, Cl) were studied for 31 different stations of the Mahanadi river–estuarine system in the eastern part of India. The seasonal nutrient variations (except SiO4-Si) exhibit higher values during monsoon season in unpolluted stations and the reverse trends for polluted stations, which are related to agricultural run-off and regional anthropogenic activities respectively. Silicate shows a well defined pattern of distribution with a higher concentration during the monsoon, which is slightly removed from the estuarine water of Mahanadi during the pre-monsoon season. The results of R-mode factor analyses revealed that anthropogenic contributions are responsible for the increase in nutrients and the decrease in DO and pH levels of the water. The magnitude of BOD with respect to total N and P demonstrates the intensity of organic pollution in the system. The removal of silicate in the saline system is clearly visible through factor analysis and the different mode of association of TSS is reflected seasonally. The relationships among the stations are highlighted by cluster analysis, represented in dendograms to categorize different levels of contamination.  相似文献   

8.
Accelerated sea level rise (slr) is expected to transform vulnerable Atlantic coastal habitats in the United States during this century. Low-elevation sandy beaches, important nesting habitat for the continued recovery of the federally threatened piping plover (Charadrius melodus) in Rhode Island, are especially vulnerable. These beaches, under a mix of private and public ownership, exist in a heterogeneous landscape of dunes, rocky headlands, salt ponds, and heavily developed areas. Understanding the extent to which piping plover nesting beaches can retreat landward under projected slr is important for prioritizing future conservation actions across multiple jurisdictions. This research examines habitat change in response to slr (0.5, 1.0, and 1.5 m) under stationary and migration beach responses and whether development blocks habitat migration for five productive piping plover nesting beaches. We found that under the stationary habitat model, all beaches lose area under all slr scenarios. For the habitat migration model, future habitat availability differs by beach depending on elevation, landward topography, and presence of development. However, across the majority of beach area, piping plover habitat will be able to migrate landward if unconstrained by future development. A coalition of public and private stakeholders already supports management efforts to help ensure plover population recovery in the area. With emerging habitat change prediction tools, these stakeholders and other partners can engage in innovative, local-level planning needed to protect wildlife habitat and commercial, residential, and infrastructure assets from sea level rise.  相似文献   

9.

Background

In spite of the prevalence of aluminum in nature, no organism has been found to date which requires this element for its biological functions. The possible health risks to human beings resulting from uptake of aluminum include detrimental effects to the hemopoietic system, the nervous system and bones. Aluminum is used in many fields and occurs in numerous foodstuffs. Food contact materials containing aluminum represent an anthropogenic source of dietary aluminum.

Results

As a result of their frequent use in private households a study was undertaken to detect migration of this metal to foodstuffs from drink containers, coffee pots, grill pans, and camping cookware made of aluminum.

Conclusions

An estimate of the health risk to consumers is calculated, based on the tolerable weekly intake (TWI) specified by the European Food Safety Authority of 1 mg/kg body weight for all groups of people. In some instances the TWI is significantly exceeded, dependent upon the food contact material and the food itself.
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