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511.
The management of swine manure is becoming an important environmental issue in Chile. One option for the final disposal of manure is to use it as a biofertilizer, but this practice could impact the surrounding environment. To assess the potential environmental impacts of the use of swine manure as a biofertilizer, we propose a method to identify zones of environmental risk through indices. The method considers two processes: nutrient runoff and solute leaching, and uses available information about soils, crops and management practices (irrigation, fertilization, and rotation). We applied the method to qualitatively assess the environmental risk associated with the use of swine manure as a biofertilizer in an 8,000-pig farm located in Central Chile. Results showed that the farm has a moderate environmental risk, but some specific locations have high environmental risks, especially those associated with impacts on areas surrounding water resources. This information could assist the definition of better farm-level management practices, as well as the preservation of riparian vegetation acting as buffer strips. The main advantage of our approach is that it combines qualitative and quantitative information, including particular situations or field features based on expert knowledge. The method is flexible, simple, and can be easily extended or adapted to other processes.  相似文献   
512.
Diatoms and macroinvertebrates have been extensively used as water quality indicators in Europe for the last two decades. In Portugal, the use of biological indicators to assess water quality in rivers has increased greatly. The aim of this work was to assess the water quality and ecological status of the Ul River in order to evaluate its ability for the establishment of a fluvial beach, using periphytic diatoms and macroinvertebrates as indicators. Four sites were selected along the Ul River. At each site, biological, physical, and chemical parameters were investigated. Epilithic diatoms and macroinvertebrates were sampled. The Specific Polluosensitivity Index and the Biological Diatom Index were applied to diatom data, while for macroinvertebrates, the Iberian Biological Monitoring Working Party (IBMWP) was used. According to the results obtained, it was possible to conclude that up to now, this river does not possess the ideal conditions for the establishment of a fluvial beach. We concluded that epilithic diatoms and macroinvertebrates provided consistent information on water quality assessment and can be used as biological indicators of the water quality in Ul River.  相似文献   
513.
The purpose of this paper is to analyse the spread of pesticide practices with respect to crop production (wheat, barley, and rapeseed) in French agriculture and to evaluate the potential pesticide reductions for cost-efficient farmers. This is made possible by conducting a double-step analysis based on non-parametric robust technology. First, from a panel data of 650 farms over a 12-year period located in the French department of Meuse, we selected the cost-efficient farms thanks to a robust free disposal hull (RFDH) technology. A second RFDH frontier analysis was run only on the selected cost-efficient farms thus enabling us to reveal the units which minimize the pesticide use per hectare while maintaining constant yields. Therefore, all the different total cost-efficient practices among farmers were evaluated in terms of pesticide per hectare and the minimum uses were selected. Our main conclusion is that the pesticide reductions per hectare for the cost-efficient farms could reach 24 %.  相似文献   
514.
To add data on trace metal contamination of Humboldt penguins in the South Pacific, levels of trace metals (As, Hg, Pb, Cu, Zn, and Cd) and porphyrins (copro-, uro-, and proto-) in excreta of Humboldt penguins that inhabit some important nesting sites on the northern coast of Chile were determined. Fresh excreta were collected on Pan de Azúcar Island, Chañaral Island, and Cachagua Island, from December 2011 to January 2012. Concentration of metals was determined by flame atomic absorption spectrophotometry, whereas porphyrins levels were measured by fluorimetric analysis. Concentrations (dry weight) of Cu (199.67 μg g?1), As (7.85 μg g?1), and Pb (12.78 μg g?1) were higher (p?≤?0.05) in Cachagua Island. Colonies from Pan de Azúcar Island showed the highest levels of Hg (0.76 μg g?1), Cd (47.70 μg g?1), and Zn (487.10 μg g?1). Samples from Cachagua Island showed the highest (p?≤?0.05) levels of copro- (2.16 nmol g?1), uro- (2.20 nmol g?1), and protoporphyrins (2.23 nmol g?1). There was a positive correlation between the metals As, Pb, and Cu with uro-, copro-, and protoporphyrins. The results indicated that penguin colonies from Cachagua Island are more exposed to metal contamination than penguin colonies from Pan de Azúcar and Chañaral Islands, thus being more likely to develop certain diseases caused by contamination with metals. Considering biomagnification, the metals detected in the excreta of Humboldt penguins can be a source of contamination from marine environments to terrestrial ecosystems, which could also affect other living organisms.  相似文献   
515.
Some common organochlorine, organophosphorus and pyrethroid insecticides were analysed in agricultural soil samples (n?=?35) and surface water and groundwater samples (n?=?25) collected from coastal areas of vegetable production in Togo. Analytical methods included solvent extraction of the insecticide residues and their subsequent quantification using GC-ECD. δ-HCH, heptachlor epoxide, 4,4-DDE, endosulphan (α, β and sulphate), lambda-cyalothrin and chlorpyrifos were found in the soil samples with concentrations that varied from non-detectable (ND) to 26.93 μg kg?1 dry weight. For water samples, heptachlor epoxide, 2,4-DDD, 4,4-DDD, 4,4-DDE and endosulphan (α, β, and sulphate) were found at contamination levels that varied from ND to 0.116 μg L?1. The concentration of insecticide residues detected in the water samples was below the limits set by the World Health Organization (WHO) and also by the European Union (EU), with the exception of the concentration of endosulphan sulphate at the Aného site, which was 0.116 μg L?1.  相似文献   
516.
Nucella lapillus (L.) is a marine gastropod mollusc widely used as a bioindicator of TBT pollution in the North Atlantic coastlines. The species reproductive cycle and the male penis length seasonal/spatial variation were studied at a single site at Aveiro seashore (NW Portugal) between December 2005 and June 2007. The main objective of this work is to assess if the "Relative Penis Size Index" (RPSI)--an important imposex assessment index--varies seasonally and spatially in the same sampling site and how this can affect results obtained in imposex monitoring programmes. Animals able to reproduce were found every month but a seasonal pattern in N. lapillus reproductive cycle was evident. Female gametogenic maturation varied seasonally and a decrease in capsule gland volume and condition factor occurred in late summer/early autumn. The gametogenesis in males did not show a significant seasonal variation as in females but the condition factor, penis length, amount of sperm and prostate volume also diminished in late summer/early autumn. On the other hand, males that were close to egg capsules clusters had larger penises than those far away from clusters. The temporal and spatial male penis length variation introduces a bias on imposex assessment results when using RPSI and the magnitude of the error involved is evaluated for different TBT pollution levels scenarios. We consider that RPSI provides interesting and complementary information that should not be excluded from monitoring programmes, but temporal or spatial comparisons of imposex should be based on other more reliable imposex indices like the VDSI.  相似文献   
517.
Enhanced activity of actinides and some decay products has been reported for the leaves of cypress trees (Chamaecyparis nootkatensis) at the edge of the Malvési uranium-processing facility, southwestern France. The enhanced activity is due to the release of actinides via the smokestacks and from artificial ponds inside the facility. This study was conducted to characterize airborne particulate matter deposited on the leaf surfaces and to investigate whether or not radioactive particles may be identified. Air-dried leaf samples were examined by scanning electron microscopy, in combination with energy-dispersive X-ray spectrometry. The samples were scanned systematically in both secondary and backscattered electron modes. Particles ranging in size from <200 nm to ~40 μm were found on most portions of the adaxial leaf surface, but they are especially abundant at the boundary between facial and lateral leaves. The majority of the analyzed particles could be attributed to five principal classes: carbonates, silicates, sulfates, oxides/hydroxides, and halides. In addition, other types of particles were found, including Fe alloys; scheelite-group phases; phosphates; sulfides; and fly ash spheres. Similar particles were also observed on the surface of a wheat sample used for comparison. Of special interest are U-rich particles, which were observed on the cypress leaves only and which were identified as U oxides, except for one particle, which was a U-oxide-fluoride. These U-rich particles were released into the atmosphere by the nuclear facility prior to their deposition on the leaf surfaces. As most of the U-rich particles are <2.5 μm across, they are respirable. Once inhaled, particles containing alpha-emitting isotopes represent a potentially long-term source of ionizing radiation inside the lungs and thus, pose a threat to the health of people living nearby.  相似文献   
518.
Only a few studies have assessed the joint incorporation of heavy metals into agricultural systems based on the range of agrochemicals used on a specific agricultural crop. This study was conducted to assess the heavy metals input through application of the main agrochemicals used in Brazilian tobacco fields. A total of 56 samples of different batches of 5 fertilizers, 3 substrates, 8 insecticides, 3 fungicides, 2 herbicides, and 1 growth regulator commonly used in the cultivation of tobacco in Brazil’s Southern Region were collected from 3 warehouses located in the States of Rio Grande do Sul, Santa Catarina, and Paraná. The total As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, and Zn content of the samples was then determined and compared with the regulations of different countries and information found in the available literature. The fertilizers were identified as the primary source of heavy metals among the agrochemicals used. Application of pesticides directly to the shoots of tobacco plants contributed very little to the supply of heavy metals. The agrochemicals used in Brazilian tobacco fields provide lower inputs of the main heavy metals that are nonessential for plants than those registered in the international literature for the majority of crop fields in different regions of the world.  相似文献   
519.
520.
Operational air quality models have become an important tool to assist the decision makers in European Environmental Offices at different levels: cities, regional and state. Because of the important advance on computing capabilities during the last few years the possibility of incorporating the complex research and academic mesoscale air quality models under routine operational basis has become a reality. OPANA model is the operational version of the research model ANA (Atmospheric mesoscale Numerical pollution model for regional and urban Areas). This model is a limited area model (mesoscale beta) and the capability to extend the prediction horizon is limited unless proper boundary conditions are provided during long simulations. In this contribution we show how AVN/MRF (NOAA) vertical numerical meteorological soundings are incorporated to the OPANA system by using JAVA technology. This new feature helps to keep the air quality model into medium power workstations and the performance is improved accordingly. This technology avoids running mesoscale models over larger areas (continental scale) to accordingly increase the forecasting temporal horizon.  相似文献   
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