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61.
Forest fires are an integral part of the ecology of the Mediterranean Basin; however, fire incidence has increased dramatically during the past decades and fire is expected to become more prevalent in the future due to climate change. Fuel modification by prescribed burning reduces the spread and intensity potential of subsequent wildfires. We used the most recently published data to calculate the average annual wildfire CO(2) emissions in France, Greece, Italy, Portugal and Spain following the IPCC guidelines. The effect of prescribed burning on emissions was calculated for four scenarios of prescribed burning effectiveness based on data from Portugal. Results show that prescribed burning could have a considerable effect on the carbon balance of the land use, land-use change and forestry (LULUCF) sector in Mediterranean countries. However, uncertainty in emission estimates remains large, and more accurate data is needed, especially regarding fuel load and fuel consumption in different vegetation types and fuel layers and the total area protected from wildfire per unit area treated by prescribed burning, i.e. the leverage of prescribed burning.  相似文献   
62.
Environmental Science and Pollution Research - Coal extraction and processing generate environmental contamination, which has several negative impacts on human health. Hematological and biochemical...  相似文献   
63.
The purpose of this study was to establish a subsampling procedure for benthic macroinvertebrates to aid in the development of a multimetric index to assess the biological condition of streams. Data from six streams that are considered minimally impaired were used. Subsampling was done using a device divided into 24 quadrats. The sediment from each quadrat was sorted, and all organisms were removed and identified. Richness metrics were the most affected by subsample size. Relative-abundance metrics were the most stable, proving that the sample was well distributed throughout the tray and abundance proportions were maintained. The results showed that the macroinvertebrate assemblage present in the six quadrats was similar to that present in the full sample. These analyses indicated that six quadrats, randomly designated, with a minimum of 200 collected specimens could be used in place of the full sample. In routine water management, managing time and costs are a major challenge; therefore, this type of simplification is absolutely necessary to ensure that a biomonitoring tool is useful for practical applications.  相似文献   
64.
In this experimental program, the effects of non-methane organic compounds (NMOCs) on the biological methane (CH4) oxidation process were examined. The investigation was performed on compost experiments incubated with CH4 and selected NMOCs under different environmental conditions. The selected NMOCs had different concentrations and their effects were tested as single compounds and mixtures of compounds. The results from all experimental sets showed a decrease in CH4 oxidation capacity of the landfill bio-cover with the increase in NMOCs concentrations. For example, in the experiment using compost with 100% moisture content at 35 °C without any NMOCs the Vmax value was 35.0 μg CH4h-1gwet wt-1. This value was reduced to 19.1 μg CH4h-1gwet wt-1 when mixed NMOCs were present in the batch reactors under the same environmental conditions. The experimental oxidation rates of CH4 in the presence of single and mixed NMOCs were modeled using the uncompetitive inhibition model and kinetic parameters, including the dissociation constants, were obtained. Additionally, the degradation rates of the NMOCs and co-metabolic abilities of methanotrophic bacteria were estimated.  相似文献   
65.
Pesticides are among the most widely used chemicals in the world. Because of the widespread use of agricultural chemicals in food production, people are exposed to low levels of pesticide residues through their diets. Scientists do not yet have a total understanding of the health effects of these pesticide residues. This work aims to determine differences in terms of pesticide residue content in Portuguese strawberries grown using different agriculture practices. The Quick, Easy, Cheap, Effective, Rugged, and Safe sample preparation method was conducted and shown to have good performance for multiclass pesticides extraction in strawberries. The screening of 25 pesticides residue was performed by gas chromatography?Ctandem mass spectrometry. In quantitative validation, acceptable performances were achieved with recoveries of 70?C120 and <12?% residual standard deviation for 25 pesticides. Good linearity was obtained for all the target compounds, with highly satisfactory repeatability. The limits of detection were in the range of 0.1?C28???g/kg. The method was applied to analyze strawberry samples from organic and integrated pest management (IPM) practices harvested in 2009?C2010. The results showed the presence of fludioxonil, bifenthrin, mepanipyrim, tolylfluanid, cyprodinil, tetraconazole, and malathion when using IPM below the maximum residue levels.  相似文献   
66.
Weldon Spring is consistently enriched in 18 O relative to other karst springs in east-central Missouri and western Illinois, suggesting an evaporated source component. Regional potentiometric head maps of the shallow aquifer suggest that Prairie Lake, an artificial lake built between 1954 and 1982, could represent this component. Isotopic, biological and chemical tracing of the spring conclusively verify the hypothesis that this lake has impacted Weldon Spring. Mixing calculations indicate that Weldon Spring is now comprised of approximately 80% lake water and 20% groundwater. Recent measurements indicate that the discharge rate of the spring is now approximately 10 times the rate prior to the construction of the lake, confirming the augmentation of flow by a new source. Analysis of the isotopic trends indicates that the subsurface travel time is short, and suggests that the conduits connecting the lake and the spring may be progressively enlarging.  相似文献   
67.
Road runoff is a linear diffuse source of pollution, with very specific characteristics. This study intends to improve the understanding of road runoff impacts in water bodies in Portugal. The chosen case study is S. Domingos reservoir catchment. The study analyzed land uses, the presence of pollution sources, and gathered temporal water quality data and performed site measurements and sample collection. The water quality data for the reservoir was provided by the national water quality monitoring system from the Portuguese Water Institute. The parameters selected were TSS, COD, NO3 ?, Cl?, and Cu. The results obtained revealed that the presence of IP6 highway at S. Domingos catchment affects the water quality; however, the impacts are not significant due to the high dilution effect of the reservoir volume. Agriculture, the main land use of the catchment, is responsible for introducing pollutants such as TSS, Cl?, COD, N, and P in the local water streams and at the reservoir. TSS, COD, and Cu are pollutants generated by the road. The success of the study was very much dependent on the availability of 12 years of historic water quality data for S. Domingos reservoir, and the use of the moving average method. Taking into consideration the high variability of hydrological variables in Mediterranean climates, the concentration of pollutants in the water bodies must always be assessed in a significant time period.  相似文献   
68.
Severely fragmented habitats increase the risk of extirpation of native mammal populations through isolation, increased edge effects, and predation. Therefore, monitoring the movement of mammal populations through anthropogenically altered landscapes can inform conservation. We used metabarcoding of invertebrate-derived DNA (iDNA) from carrion flies (Calliphoridae and Sarcophagidae) to track mammal populations in the wheat belt of southwestern Australia, where widespread clearing for agriculture has removed most of the native perennial vegetation and replaced it with an agricultural system. We investigated whether the localization of the iDNA signal reflected the predicted distribution of 4 native species—echidna (Tachyglossus aculeatus), numbat (Myrmecobius fasciatus), woylie (Bettongia penicillata), and chuditch (Dasyurus geoffroii)—and 2 non-native, invasive mammal species—fox (Vulpes vulpes) and feral cat (Felis catus). We collected bulk iDNA samples (n = 150 samples from 3428 carrion flies) at 3 time points from 3 conservation reserves and 35 road edges between them. We detected 14 of the 40 mammal species known from the region, including our target species. Most detections of target taxa were in conservation reserves. There were a few detections from road edges. We detected foxes and feral cats throughout the study area, including all conservation reserves. There was a significant difference between the diversity (F3, 98 = 5.91, p < 0.001) and composition (F3, 43 = 1.72, p < 0.01) of taxa detections on road edges and conservation reserves. Conservation reserves hosted more native biodiversity than road edges. Our results suggest that the signals from iDNA reflect the known distribution of target mammals in this region. The development of iDNA methods shows promise for future noninvasive monitoring of mammals. With further development, iDNA metabarcoding could inform decision-making related to conservation of endangered taxa, invasive species management, and impacts of habitat fragmentation.  相似文献   
69.
70.
Sediments constitute a pollutant trap and have proven to be an efficient tool to identify environmental impacts. Sediments are considered a very important means to assess the level of contamination of water bodies because of their ability to accumulate metals and organic. The anthropogenic inputs of sewage, with or without prior treatment, in aquatic environments, affect the geochemical composition of sediment. In addition, the sediment adsorbs hydrophobic compounds found in feces, such as the fecal sterols. The granulometric and geochemical composition of the sediment of Barigüi River-Brazil was investigated. The results show that silt and clay dominate the granulometric composition of the sediments. The geochemical composition of sediments showed high concentrations of phosphorus and nitrogen. The Redfield ratios confirm the inputs of phosphorus and nitrogen. The TOC/N ratio was used to identify the source of pollution. N/TP ratios were found between 1.0 and 3.5. Clearly, an input of phosphorus, sewage is the most acceptable source, following the historic profile of the Barigüi River. High concentration of nitrogen phosphorus labels the area to be polluted by sewage. To confirm the sewage pollution, adsorbed fecal sterols in sediments were investigated. The concentration of total sterols was found between 0.86 and 304.58 μg g???1. Two distinguished scenario was found, one severely polluted and another slightly polluted. The highest concentrations of total fecal sterols were associated with sediment whose geochemical composition showed higher levels of TOC, as well as higher proportions of silt and clay. Also, epicoprostanol, a coprostanol isomer, was used as an indicator of the level of treatment or age of the fecal matter because it is formed during the treatment of wastewater and sludge digestion. If the treatment of sludge takes a long time, epicoprostanol can form from cholesterol, and relative proportions of those compounds may be used as an indicator of the presence of untreated sewage in the sediments. The epicoprostanol was found in the range between 0.02 and 9.71 μg g???1; concentration of up to 0.015 μg g???1 represents situations where there is strong contamination by sewage. All sites investigated showed a concentration of epicoprostanol higher than the value adopted as threshold. The lower concentration of epicoprostanol found for all sites is consistent with the high concentration found for coprostanol, and this is typical for untreated sewage.  相似文献   
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