Effects of air/fuel ratio on gas emissions in a small spark-ignited non-road engine operating with different gasoline/ethanol blends

This study investigates the effects of several blends of gasoline and anhydrous ethanol on exhaust emission concentrations of carbon monoxide (CO), total hydrocarbons (HCs), and nitrogen oxides (NO_x) from a small spark-ignited non-road engine (SSINRE). Tests were carried out for different air/fuel equivalence ratios as measured by lambda (λ). A 196 cm³ single-cylinder four-stroke engine-generator operating at a constant load of 2.0 kW was used; pollutant gas concentrations were measured with an automatic analyzer similar to those typically used in vehicle inspections. The results showed that as the ethanol content of the mixture increased the concentrations of CO, HCs, and NO_x reduced by 15, 53, and 34%, respectively, for values of λ < 1 (rich mixture) and by 52, 31, and 16% for values of λ > 1 (lean mixture). Overall, addition of anhydrous ethanol to the gasoline helped to reduce emissions of the pollutant gases investigated, what contributes to photochemical smog reduction and quality of life in urban areas.     

Mechanical properties of shotcrete with addition of sugarcane bagasse fiber and ash

Journal of Material Cycles and Waste Management - Shotcrete is a sprayed concrete placed on steep slopes that have been widely used because it can prevent surface weathering and erosion, and in...     

Ultracentrifugation as a direct method to concentrate viruses in environmental waters: virus-like particle enumeration as a new approach to determine the efficiency of recovery

Some health important enteric viruses are considered to be emerging waterborne pathogens and so the improvement of detection of these viruses in the aquatic environment is one of the most important steps in dealing with these pathogens. Since these viruses may be present in low numbers in water, it is necessary to concentrate water samples before viral detection. Although there are several methods to concentrate viruses in environmental waters, all present some drawbacks and consequently the method should be chosen that, despite its limitations, is adequate to achieve the aim of each study. As the effectiveness of the concentration methods is evaluated by determining the efficiency of viral recovery after concentration, it is important to use a simple and effective approach to evaluate their recovery efficiency. In this work ultracentrifugation, usually used as a secondary step for virus concentration, was evaluated as the main method to concentrate directly viruses in environmental water samples, using the microscopic enumeration of virus-like particles (VLP) as a new approach to estimate the efficiency of recovery. As the flocculation method is currently employed to concentrate viruses in environmental waters, it was also used in this study to assess the efficiency of the ultracentrifugation as the main viral concentration method in environmental waters. The results of this study indicate that ultracentrifugation is an adequate approach to concentrate viruses directly from environmental waters (recovery percentages between 66 and 72% in wastewaters and between 66 and 76% in recreational waters) and that the determination of VLP by epifluorescence microscopy is a simple, fast and cheap alternative approach to determine the recovery efficiency of the viral concentration methods.     

Bioaccumulation and related effects of PCBs and organochlorinated pesticides in freshwater fish Hypostomus commersoni

Few studies have investigated the bioaccumulation of persistent organic pollutants (POPs) in Brazilian native freshwater fish. In order to evaluate the bioavailability, potential risk to human exposure and the effects of POPs in the fish Hypostomus commersoni, muscle and liver samples of thirteen specimens were collected in a lake located in the city of Ponta Grossa (Parana State, Southern Brazil). Also, the liver and gills were considered for histopathological studies, and oxidative stress was investigated in the liver. Expressive concentrations of POPs were observed in the liver and muscle, with a total of 427 ± 78.7 and 69.2 ± 18.1 ng g(-1) dry weights of polychlorinated biphenyls (PCBs), respectively. Negative correlations between the concentration of several POPs and glutathione S-transferase and glucose-6-phosphate dehydrogenase were found. Otherwise, the cholinesterase activity in the muscle and brain presented positive correlations with the concentration of POPs. The hepatic bioaccumulation of some banned pesticides like aldrin, dieldrin and DDT was associated with various histopathological findings in the liver and gills. Necrotic areas, fibrosis, leukocyte infiltration, and the absence of macrophage centers were observed in the liver, indicating both chronic exposure and immunological suppression. Neoplasic changes were observed in the gills, confirming the carcinogenic potential reported for some of the investigated pollutants. The current work was the first to study the bioaccumulation of POPs in H. commersoni, an important species in ecological aspects and as a vehicle to human exposure to PCBs and organochlorine pesticides (OCPs).     

Critical analysis of the potential of Ipomoea nil'Scarlet O'Hara' for ozone biomonitoring in the sub-tropics

This study aimed to analyze critically the potential of Ipomoea nil'Scarlet O'Hara' for O(3) biomonitoring in the sub-tropics. Four field experiments (one in each season of 2006) were carried out in a location of the city of S?o Paulo mainly polluted by O(3). Each experiment started with 50 plants, and lasted 28 days. Sub-lots of five plants were taken at intervals between three or four days long. Groups of four plants were also exposed in closed chambers to filtered air or to 40, 50 or 80 ppb of O(3) for three consecutive hours a day for six days. The percentage of leaf injury (interveinal chloroses and necroses), the concentrations of ascorbic acid (AA) and the activity of superoxide dismutase (SOD) and peroxidases (POD) were determined in the 5th, 6th and 7th oldest leaves on the main stem of the plants taken in all experiments. Visible injury occurred in the plants from all experiments. Seasonality in the antioxidant responses observed in plants grown under field conditions was associated with meteorological variables and ozone concentrations five days before leaf analyses. The highest levels of antioxidants occurred during the spring. The percentage of leaf injury was explained (R(2) = 0.97, p < 0.01) by the reduction in the levels of AA and activity of POD five days before the leaf analyses and by the reduction in the levels of particulate matter, and enhancement of temperature and global radiation 10 days before this same day. Although I. nil may be employed for qualitative O(3) biomonitoring, its efficiency for quantitative biomonitoring in the sub-tropics may be compromised, depending on how intense the oxidative power of the environment is.     

Ensemble Techniques to Improve Air Quality Assessment: Focus on O3 and PM

Five air quality models were applied over Portugal for July 2006 with an ensemble purpose. These models were used, with their own meteorology, parameterizations, boundary conditions and chemical mechanisms, but with the same emission data. The validation of the individual models and its ensemble for ozone (O₃) and particulate matter was performed using monitoring data from 22 background stations over Portugal. After removing the bias from each model, different ensemble techniques were applied and compared. Besides the median, several weighted ensemble approaches were tested and intercompared: static (SLR) and dynamic (DLR) multiple linear regressions (using less-square optimization method) and the Bayesian Model Averaging (BMA) methodology. The goal of the comparison is to estimate to what extent the ensemble analysis is an improvement with respect to the single model results. The obtained results revealed that no one of the 4 tested ensembles clearly outperforms the others on the basis of statistical parameters and probabilistic analysis (reliability and resolution properties). Nevertheless, statistical results have shown that the application of the weights slightly improves ensemble performance when compared to those obtained from the median ensemble. The same statistical analysis together with the probabilistic measures demonstrates that the SLR and BMA methods are the best performers amongst the assessed methodologies.     

Analytical results and effective dose estimation of the operational Environmental Monitoring Program for the radioactive waste repository in Abadia de Goiás from 1998 to 2008

This paper presents the results of the Environmental Monitoring Program for the Radioactive waste repository of Abadia de Goiás, which was originated from the accident of Goiania, conducted by the Regional Center of Nuclear Sciences (CRCN-CO) of the National Commission on Nuclear Energy (CNEN), from 1998 to 2008.The results are related to the determination of ¹³⁷Cs activity per unit of mass or volume of samples from surface water, ground water, depth sediments of the river, soil and vegetation, and also the air-kerma rate estimation for gamma exposure in the monitored site.In the phase of operational Environmental Monitoring Program, the values of the geometric mean and standard deviation obtained for ¹³⁷Cs activity per unit of mass or volume in the analyzed samples were (0.08 ± 1.16) Bq.L⁻¹ for surface and underground water, (0.22 ± 2.79) Bq.kg⁻¹ for soil, and (0.19 ± 2.72) Bq.kg⁻¹ for sediment, and (0.19 ± 2.30) Bq.kg⁻¹ for vegetation. These results were similar to the values of the pre-operational Environmental Monitoring Program.With these data, estimations for effective dose were evaluated for public individuals in the neighborhood of the waste repository, considering the main possible way of exposure of this population group.The annual effective dose obtained from the analysis of these results were lower than 0.3 mSv.y⁻¹, which is the limit established by CNEN for environmental impact in the public individuals indicating that the facility is operating safely, without any radiological impact to the surrounding environment.     

Associations between forest characteristics and socio-economic development: a case study from Portugal

The integration of socio-economic and environmental objectives is a major challenge in developing strategies for sustainable landscapes. We investigated associations between socio-economic variables, landscape metrics and measures of forest condition in the context of Portugal. The main goals of the study were to 1) investigate relationships between forest conditions and measures of socio-economic development at national and regional scales, 2) test the hypothesis that a systematic variation in forest landscape metrics occurs according to the stage of socio-economic development and, 3) assess the extent to which landscape metrics can inform strategies to enhance forest sustainability. A ranking approach and statistical techniques such as Principal Component Analysis were used to achieve these objectives. Relationships between socio-economic characteristics, landscape metrics and measures of forest condition were only significant in the regional analysis of municipalities in Northern Portugal. Landscape metrics for different tree species displayed significant variations across socio-economic groups of municipalities and these differences were consistent with changes in characteristics suggested by the forest transition model. The use of metrics also helped inform place-specific strategies to improve forest management, though it was also apparent that further work was required to better incorporate differences in forest functions into sustainability planning.     

Bioaccumulation of polychlorinated biphenyls in the eel (Anguilla anguilla) at the Camargue Nature Reserve - France

Fish consumption is a potential source of human exposure to pollutants. Here, we study residue levels of PCBs in the eel, Anguilla anguilla, from the Nature Camargue Reserve in southern France. Chromatographic analysis (GC-ECD) found seventy identifiable congeners, among which, 10 are considered as dioxin-like PCBs, such as the non-ortho PCB 81 and the mono-ortho chlorobiphenyls PCB105, 114, 118, 123, 156, 157, 167, 170, 180. Toxic Equivalents (TEQ, WHO 2005 TEF-Toxic Equivalent Factors) varied among sites with a maximum in eels from Mornès (29.6pgg(-1) dry weight). Indicator PCBs (28, 52, 101, 118, 138, 153 and 180) were 22% and 29% of the total PCBs in livers and muscles respectively. Greater homogeneous bioaccumulation in muscle than that in liver suggests an increase risk for humans due to fish consumption.     

基于层次分析法的城市河流生态修复评估

城市的发展改变了许多河流的自然水文环境,并导致河流生态系统中水质、物理生境和生物完整性下降。评估受损河流水体修复的效果,需要结合物理、化学的参数,以及对生物结构、多样性和过程的影响。构建了包含河流水力、水质、水生生物、河岸带及物理结构5个方面15个指标的城市河流生态修复评估指标体系,运用群组决策的层次分析法(AHP),确定了各指标的权重,重要性排序前5位依次为：水质污染指数、鱼类IBI、水源补给量、藻类多样性、透明度。并以我国南方城市岐江河整治修复状况为例进行综合评价,结果表明,河流生态系统修复评估结果为可以接受,体现了河流整治工程使河流水质、生态的状况有所改善,但河流生态系统恢复需要较长的周期,修复初期生态系统仍处于受损状态。〖