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301.
Anthony R. Buda David R. DeWalle 《Atmospheric environment (Oxford, England : 1994)》2009,43(29):4453-4464
Stable isotopes of NO3? (δ15N–NO3? and δ18O–NO3?) were monitored in precipitation at a central Pennsylvania site during six storm events in 2005 to determine whether information on atmospheric oxidants (e.g., O3, NO2, and NOx), and storm tracks (using the NOAA HYSPLIT model) were capable of explaining observed seasonal and within-storm isotopic variation. Results showed that δ15N–NO3? and δ18O–NO3? in precipitation varied significantly during individual storm events. Seasonally, δ15N–NO3? and δ18O–NO3? in precipitation followed a pattern of depletion during the summer months and enrichment during the winter months. NO3? precursor concentrations and atmospheric oxidants were useful for explaining the seasonal and within-storm variation of δ15N–NO3? for all six storm events as evidenced by negative relationships with NO2:NOx ratios and ozone (O3). In comparison, δ18O–NO3? was positively related to O3 in three dormant season storms, which suggested that the O3 oxidation pathway was important for producing the high δ18O–NO3? observed in wintertime precipitation. Storm track information was especially useful for describing differences in δ15N–NO3?. Cool-sector storms originating from the E/NE produced slightly negative δ15N–NO3? values characteristic of automobile emissions, whereas warm-sector storms with tracks from the SW/S/SE produced slightly positive δ15N–NO3? values characteristic of coal-fired emissions. Lightning also may have been an important source of atmospheric NO3? during two warm-sector thunderstorms. This study showed that (1) information about oxidant levels can be useful to predict the seasonal and within-storm variation of NO3? stable isotopes in precipitation, and (2) knowledge of storm tracks (warm-sector versus cool-sector) may be important for determining sources of NO3? in wet deposition. 相似文献
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Methyl tertiary‐butyl ether (MTBE) is commonly used as a fuel additive because of its many favorable properties that allow it to improve fuel combustion and reduce resulting concentrations of carbon monoxide and unburnt hydrocarbons. Unfortunately, increased production and use have led to its introduction into the environment. Of particular concern is its introduction into drinking water supplies. Accordingly, research studies have been initiated to investigate the treatment of MTBE‐contaminated soil and groundwater. The summer 2000 issue of Remediation reported the results of an initial study conducted by the authors to evaluate the treatment of MTBE using Fenton's reagent. In this follow‐up study, experiments were conducted to further demonstrate the effectiveness of using Fenton's reagent (H2O2:Fe+2) to treat MTBE‐contaminated groundwater. The concentration of MTBE was reduced from an initial concentration of 1,300 μg/l (14.77 μ moles) to the regulatory level of 20 μg/l (0.23 μ moles) at a H2O2:Fe+2 molar ratio of 1:1, with ten minutes of contact time and an optimum pH of 5. The by‐products, acetone and tertiary butyl alcohol, which are always present in MTBE in trace amounts, were not removed even after 60 minutes of reaction time. © 2002 Wiley Periodicals, Inc. * 相似文献
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Raymond Anthony 《Journal of Agricultural and Environmental Ethics》2012,25(4):543-552
I consider Paul Thompson’s Agrarian Vision from the perspective of the philosophy of technology, especially as it relates to certain questions about public engagement and deliberative democracy around food issues. Is it able to promote an attitudinal shift or reorientation in values to overcome the view of “food as device” so that conscientious engagement in the food system by consumers can become more the norm? Next, I consider briefly, some questions to which it must face up in order to move closer in dismantling the barriers that inhibit the capacity for virtuous caretaking of the food system at various levels. Lastly, and more deeply, how successful might agrarianism be in inculcating citizenship values (ones that go beyond food ethics as a private affair), for the democratization of agricultural technologies? Might the Jeffersonian foundation to which the agrarianism (a la) Thompson appeals need something like a contemporary theory of justice in order to facilitate the reconstitution of our politico-moral selves? How can it help guide appropriate ruminations on the intra and intergenerational question, “What do we want the shape of our current and future social and political institutions to look like in relation to food?” 相似文献
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Wang Meichen Bera Gopal Mitra Kusumica Wade Terry L. Knap Anthony H. Phillips Timothy D. 《Environmental science and pollution research international》2021,28(6):6758-6770
Environmental Science and Pollution Research - Heavy metal exposure in humans and animals commonly occurs through the consumption of metal-contaminated drinking water and food. Although many... 相似文献
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Using soundscapes to detect variable degrees of human influence on tropical forests in Papua New Guinea
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Zuzana Burivalova Michael Towsey Tim Boucher Anthony Truskinger Cosmas Apelis Paul Roe Edward T. Game 《Conservation biology》2018,32(1):205-215
There is global concern about tropical forest degradation, in part, because of the associated loss of biodiversity. Communities and indigenous people play a fundamental role in tropical forest management and are often efficient at preventing forest degradation. However, monitoring changes in biodiversity due to degradation, especially at a scale appropriate to local tropical forest management, is plagued by difficulties, including the need for expert training, inconsistencies across observers, and lack of baseline or reference data. We used a new biodiversity remote‐sensing technology, the recording of soundscapes, to test whether the acoustic saturation of a tropical forest in Papua New Guinea decreases as land‐use intensity by the communities that manage the forest increases. We sampled soundscapes continuously for 24 hours at 34 sites in different land‐use zones of 3 communities. Land‐use zones where forest cover was fully retained had significantly higher soundscape saturation during peak acoustic activity times (i.e., dawn and dusk chorus) compared with land‐use types with fragmented forest cover. We conclude that, in Papua New Guinea, the relatively simple measure of soundscape saturation may provide a cheap, objective, reproducible, and effective tool for monitoring tropical forest deviation from an intact state, particularly if it is used to detect the presence of intact dawn and dusk choruses. 相似文献