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71.
Scott W. Stine Inhong Song Christopher Y. Choi Charles P. Gerba 《Food and environmental virology》2011,3(2):86-91
The purpose of this study was to quantify the transfer of viral and bacterial pathogens in water used to dilute pesticides
sprayed onto the surfaces of cantaloupe, iceberg lettuce, and bell peppers. The average percent transfer of bacteria was estimated
to range from 0.00021 to 9.4%, while average viral transfer ranged from 0.055 to 4.2%, depending on the type of produce. Based
on these values the concentrations of hepatitis A virus (HAV) and Salmonella in water necessary to achieve a 1:10,000 annual risk of infection were calculated. Under worst case scenario assumptions,
in which a pesticide is applied on the same day that the produce is harvested and when maximum transfer values are used, concentrations
of 1.5 × 10−3 CFU Salmonella or 2.7 × 10−7 MPN HAV per 100 ml of the water used for application would result in 1:10,000 annual infection risk to anyone who consumes
the fresh produce. If harvesting does not occur until at least 14 days after the application, to produce the same risk of
infection, the numbers of Salmonella in 100 ml of water used to dilute the pesticides will be greater by up to five orders of magnitude, while the HAV numbers
will have increased by up to two orders of magnitude. Based on the reported concentrations of enteric viruses in surface and
ground waters in the United States, a 1:10,000 annual risk of infection could easily be exceeded with some groundwater sources
used in the United States. To reduce the risks associated with the consumption of fresh produce, water used to prepare pesticides
in spray applications should be evaluated for its microbiological quality. 相似文献
72.
The goal of this study was to better quantify the degree of viral contamination of tomato and cucumber in relationship to
virus type, soil type, and irrigation method. Tomatoes and cucumbers were grown in ten-gallon (37.8 L) buckets filled with
Pima clay loam or Brazito sandy loam soils. Plants were irrigated with secondary wastewater effluent using surface drip irrigation
or subsurface drip irrigation. At specified time intervals irrigation water was seeded with bacteriophages MS-2 and P22, poliovirus
type 1 (PV1), enteric adenovirus 40 (Ead 40), and hepatitis A virus. Surface drip irrigation always resulted in viral contamination
of both the above and below ground parts of both crops. The roots showed the greatest level of contamination, followed by
leaves and fruits. In contrast, with subsurface drip irrigation no viruses were detected in any of the above ground plant
surfaces. It was found that under similar soil type and irrigation method, risk of crop contamination was similar for all
of the viruses studied. It can be concluded that method of irrigation is the single most critical factor in the contamination
trend of different parts of crop plants. Plant parts can be categorized into three groups (root, stem, and leaf/fruit) based
on the risk of viral contamination from irrigation water. 相似文献
73.
A little known side effect of the atmospheric air pollution is the degradation of photovoltaic (PV) cells’ performance due to the deposition of solid particles varying in composition, size and origin. In this context, an experimental-based investigation is conducted in order to compare the energy performance of two identical pairs of PV-panels; the first being clean and the second being artificially polluted with ash, i.e. a by-product of incomplete hydrocarbons’ combustion mainly originating from thermal power stations and vehicular exhausts. A series of systematic measurements of current intensity, voltage output and solar radiation are executed simultaneously for the clean and the polluted PV-panel, so that the effect of several mass depositions on the PVs’ power output, energy yield and conversion efficiency may be determined. According to the results, a considerable deterioration of the PV-panels’ performance is obtained, i.e. almost 30% energy reduction per hour or 1.5% efficiency decrease (in absolute terms) for ash accumulation on the panels’ surface reaching up to 0.4 mg/cm2. 相似文献
74.
ISO 14001 certification and financial performance: selection-effect versus treatment-effect 总被引:1,自引:0,他引:1
Iñaki Heras-Saizarbitoria José F. Molina-Azorín Gavin P.M. Dick 《Journal of Cleaner Production》2011,19(1):1-12
The paper explores the bi-directional relationship between ISO 14001 certification and financial performance with the aim of shedding light on whether better performance is due to the beneficial effects of ISO 14001 or due to selection-effects where better performance precedes accreditation. The study uses a five year longitudinal analysis to compare the financial performance of firms in Spain before and after certification. The results of a multivariate panel data analysis find that firms with better than average performance have a greater propensity to pursue accreditation but there is no evidence that improvements in performance follow certification. This suggests that the inference that environmental variables cause improved financial performance may be unwise in research studies that can only measure association. 相似文献
75.
S. Veerasingam R. Venkatachalapathy S. Sudhakar P. Raj V. Rajeswari 《环境科学学报(英文版)》2011,23(7):1129-1134
Eight mollusc species and sediment samples collected from three different stations along Tamilnadu coast, Bay of Bengal, India
were analysed for the levels of petroleum hydrocarbons to elucidate the status of the petroleum residues in mollusc meant for human
consumption. The concentrations of petroleum hydrocarbons in sediments along Tamilnadu coast varied from 5.04–25.5 g/g dw (dry
weight). High concentration of petroleum hydrocarbons in the sediment of Uppanar estuary (25.5 1.45 g/g dw) was perhaps land
and marine based anthropogenic sources of this region. The petroleum hydrocarbon residues in eight mollusc species collected from
Uppanar, Vellar and Coleroon estuaries varied between 2.44–6.04 g/g ww (wet weight). Although the concentration of petroleum
hydrocarbons in sediment of the Uppanar region was markedly higher than the background, the petroleum hydrocarbon residues in
mollusc collected from Uppanar estuary did not suggest bioaccumulation. The results signified that industrial growth has affected the
aquatic environments and regular monitoring will help to adopt stringent pollution control measures for better management of the
aquatic region. 相似文献
76.
P. Kaniewska K. R. N. Anthony E. M. Sampayo P. R. Campbell O. Hoegh-Guldberg 《Marine Biology》2014,161(2):313-328
Reef-building corals are an example of plastic photosynthetic organisms that occupy environments of high spatiotemporal variations in incident irradiance. Many phototrophs use a range of photoacclimatory mechanisms to optimize light levels reaching the photosynthetic units within the cells. In this study, we set out to determine whether phenotypic plasticity in branching corals across light habitats optimizes potential light utilization and photosynthesis. In order to do this, we mapped incident light levels across coral surfaces in branching corals and measured the photosynthetic capacity across various within-colony surfaces. Based on the field data and modelled frequency distribution of within-colony surface light levels, our results show that branching corals are substantially self-shaded at both 5 and 18 m, and the modal light level for the within-colony surface is 50 μmol photons m?2 s?1. Light profiles across different locations showed that the lowest attenuation at both depths was found on the inner surface of the outermost branches, while the most self-shading surface was on the bottom side of these branches. In contrast, vertically extended branches in the central part of the colony showed no differences between the sides of branches. The photosynthetic activity at these coral surfaces confirmed that the outermost branches had the greatest change in sun- and shade-adapted surfaces; the inner surfaces had a 50 % greater relative maximum electron transport rate compared to the outer side of the outermost branches. This was further confirmed by sensitivity analysis, showing that branch position was the most influential parameter in estimating whole-colony relative electron transport rate (rETR). As a whole, shallow colonies have double the photosynthetic capacity compared to deep colonies. In terms of phenotypic plasticity potentially optimizing photosynthetic capacity, we found that at 18 m, the present coral colony morphology increased the whole-colony rETR, while at 5 m, the colony morphology decreased potential light utilization and photosynthetic output. This result of potential energy acquisition being underutilized in shallow, highly lit waters due to the shallow type morphology present may represent a trade-off between optimizing light capture and reducing light damage, as this type morphology can perhaps decrease long-term costs of and effect of photoinhibition. This may be an important strategy as opposed to adopting a type morphology, which results in an overall higher energetic acquisition. Conversely, it could also be that maximizing light utilization and potential photosynthetic output is more important in low-light habitats for Acropora humilis. 相似文献
77.
V.S. Yaliwal N.R. Banapurmath P.G. Tewari 《International Journal of Sustainable Engineering》2014,7(3):253-268
Renewable and alternative fuels have numerous advantages compared with fossil fuels, as they are renewable and biodegradable, and provide food and energy security and foreign exchange savings besides addressing environmental concerns and socio-economic issues. In this context, present work was carried out to investigate the feasibility of alternative and renewable fuels derived from biomass feedstock of different origin for engine applications. The present study was also extended to study the effect of producer gas composition derived from different biomass feedstock on the performance, combustion and emission characteristics of a single-cylinder, four-stroke, direct injection stationary diesel engine operated on a dual-fuel mode using Honge oil methyl ester (HOME) and producer gas induction. The performance of the engine was evaluated with a constant injection timing of 27° before top dead centre, an injection pressure of 205 bar for the diesel–producer gas combination and 230 bar for the HOME–producer gas combination and a compression ratio of 17.5. The results showed that the performance of the dual-fuel engine varies with the composition of the producer gas and depends on the type of biomass feedstock used in the gasifier. Experimental investigations on the dual-fuel engine showed that brake thermal efficiency values for the engine operated using HOME–producer gas derived from babul, neem and honge woods were found to be 17.2, 14.3 and 11.56% respectively, compared to 23.8% for diesel–producer gas operation at 80% load. However, the results showed better engine performance with lower exhaust emission levels for the operation of HOME–producer gas derived from the ordinary or babul wood compared with the operation of that derived from the neem and Honge woods. In view of this, present study reveals that use of alternative and renewable fuels for dual fuel engine can be considered as an immediate solution for the development of rural areas and emergency use in the event of severe diesel fuel shortage. 相似文献
78.
N. Dolgener L. Freudenberger N. Schneeweiss P. L. Ibisch R. Tiedemann 《Regional Environmental Change》2014,14(3):1063-1072
Environmental change is likely to have a strong impact on biodiversity, and many species may shift their distribution in response. In this study, we aimed at projecting the availability of suitable habitat for an endangered amphibian species, the Fire-bellied toad Bombina bombina, in Brandenburg (north-eastern Germany). We modelled a potential habitat distribution map based on (1) a database with 10,581 presence records for Bombina from the years 1990 to 2009, (2) current estimates for ecogeographical variables (EGVs) and (3) the future projection of these EGVs according to the statistical regional model, respectively, the soil and water integrated model, applying the maximum entropy approach (Maxent). By comparing current and potential future distributions, we evaluated the projected change in distribution of suitable habitats and identified the environmental variables most associated with habitat suitability that turned out to be climatic variables related to the hydrological cycle. Under the applied scenario, our results indicate increasing habitat suitability in many areas and an extended range of suitable habitats. However, even if the environmental conditions in Brandenburg may change as predicted, it is questionable whether the Fire-bellied toad will truly benefit, as dispersal abilities of amphibian species are limited and strongly influenced by anthropogenic disturbances, that is, intensive agriculture, habitat destruction and fragmentation. Furthermore, agronomic pressure is likely to increase on productive areas with fertile soils and high water retention capacities, indeed those areas suitable for B. bombina. All these changes may affect temporary pond hydrology as well as the reproductive success and breeding phenology of toads. 相似文献
79.
Silvestre García de Jalón Ana Iglesias Ruth Cunningham Juan I. Pérez Díaz 《Regional Environmental Change》2014,14(3):1229-1242
Agricultural water management needs to evolve in view of increased water scarcity, especially when farming and natural protected areas are closely linked. In the study site of Doñana (southern Spain), water is shared by rice producers and a world heritage biodiversity ecosystem. Our aim is to contribute to defining adaptation strategies that may build resilience to increasing water scarcity and minimize water conflicts among agricultural and natural systems. The analytical framework links a participatory process with quantitative methods to prioritize the adaptation options. Bottom-up proposed adaptation measures are evaluated by a multi-criteria analysis (MCA) that includes both socioeconomic criteria and criteria of the ecosystem services affected by the adaptation options. Criteria weights are estimated by three different methods—analytic hierarchy process, Likert scale and equal weights—that are then compared. Finally, scores from an MCA are input into an optimization model used to determine the optimal land-use distribution in order to maximize utility and land-use diversification according to different scenarios of funds and water availability. While our results show a spectrum of perceptions of priorities among stakeholders, there is one overriding theme that is to define a way to restore part of the rice fields to natural wetlands. These results hold true under the current climate scenario and even more so under an increased water scarcity scenario. 相似文献
80.