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901.
Megan A. Bergauff Tony J. Ward Curtis W. Noonan Christopher P. Palmer 《Atmospheric environment (Oxford, England : 1994)》2009,43(18):2938-2943
Residential woodstoves are the single largest source of PM2.5 in Libby, MT, resulting in the community being designated as a nonattainment area for PM2.5. Beginning in 2005, a community-wide woodstove changeout program was implemented that replaced nearly 1200 old stoves with EPA-certified units. In an effort to track the reduction of woodsmoke particles throughout the program, ambient PM2.5 samples were collected before, during, and after the changeout. These samples were analyzed for seven selected woodsmoke tracers, including vanillin, acetovanillone, guaiacol, 4-ethylguaiacol (methoxyphenols), levoglucosan (sugar anhydride), abietic acid, and dehydroabietic acid (resin acids). Results of the changeout showed that PM2.5 levels decreased by 20% during the changeout period, while levels of the seven chosen tracer compounds gave variable responses. Levoglucosan levels decreased by 50% while both resin acids increased after the changeout, suggesting a change in the chemistry of the particles. No trend was observed in the levels of methoxyphenols as a group over the changeout period. The results suggest that the concentrations of woodsmoke related PM2.5 in the Libby airshed have decreased; however, the chemistry of the emitted particles also changed when old woodstoves were replaced with new EPA-certified stoves. 相似文献
902.
This article describes a template for implementing an integrated community sustainability plan. The template emphasizes community
engagement and outlines the components of a basic framework for integrating ecological, social and economic dynamics into
a community plan. The framework is a series of steps that support a sustainable community development process. While it reflects
the Canadian experience, the tools and techniques have applied value for a range of environmental planning contexts around
the world. The research is case study based and draws from a diverse range of communities representing many types of infrastructure,
demographics and ecological and geographical contexts. A critical path for moving local governments to sustainable community
development is the creation and implementation of integrated planning approaches. To be effective and to be implemented, a
requisite shift to sustainability requires active community engagement processes, political will, and a commitment to political
and administrative accountability, and measurement. 相似文献
903.
Building recycling rates through the informal sector 总被引:1,自引:0,他引:1
Many developing country cities aspire to modern waste management systems, which are associated with relatively high recycling rates of clean, source separated materials. Most already have informal sector recycling systems, which are driven solely by the revenues derived from selling recovered materials, even though they are saving the formal sector money by reducing waste quantities. There is clear potential for 'win-win' co-operation between the formal and informal sectors, as providing support to the informal sector, to build recycling rates and to address some of the social issues could reduce the overall costs of waste management for the formal sector. This paper shows that recycling rates already achieved by the informal sector can be quite high, typically in the range from 20% to 50%; often up to half of this is in the form of clean, source separated materials collected directly from households and businesses by itinerant waste buyers. Four country case studies provide a number of lessons on how this solid foundation could be used to build high recycling rates of clean materials. 相似文献
904.
Joanna Endter‐Wada Judith Kurtzman Sean P. Keenan Roger K. Kjelgren Christopher M.U. Neale 《Journal of the American Water Resources Association》2008,44(4):902-920
Abstract: Landscape water conservation is an important issue for municipalities throughout the Western United States, and especially in Utah as rapid growth strains existing water supplies. We conducted interdisciplinary research in Layton, Utah, that aimed at understanding patterns of landscape water use among households and businesses. The research project involved three basic tasks. First, a landscape “water budget” was developed by producing a calibrated and classified mosaic of landscape type and area from airborne multispectral digital imagery, integrating this information with Layton City parcel boundary data to determine landscape vegetated areas per lot, and estimating irrigation needs derived from reference evapotranspiration (ETo) obtained using weather data for the Salt Lake City metropolitan region. Second, utilizing Layton water billing data, water use for each household and business was identified and categorized as “conserving,”“acceptable” or “wasteful” by determining how much the water applied varied from actual landscape plant need. Third, surveys were administered to a random stratified sample of households and businesses in the study area to investigate various factors that were hypothesized to be predictive of wasteful watering practices. This paper primarily focuses on analysis of the household and business survey data, which explores factors affecting urban landscape water use from a human behavioral perspective. We found that the most significant factors predicting actual water use were the type of irrigation system and whether the location was a household or business. Attitudinal and motivational characteristics were not consistently associated with water use. We found that wasteful watering is the result of many factors embedded in the complex context of urban landscapes. This implies that water conservation programs should identify potential wasteful users through analyses of water billing data and direct water conservation measures at these users by focusing on site‐specific evaluations and recommendations. Water audits or water checks are one such tool that some communities have employed to help people understand and assess the quantity of water needed by and applied to their landscapes. This approach provides an opportunity to evaluate situational constraints at particular locations and design appropriate strategies for reducing water waste. 相似文献
905.
Arsenate and perchlorate toxicity, growth effects, and thyroid histopathology in hypothyroid zebrafish Danio rerio 总被引:3,自引:0,他引:3
Exposure to perchlorate or other thyrotoxic compounds can cause hypothyroidism in most vertebrates, and this may affect levels of endogenous antioxidants and cause oxidative stress. Arsenic also induces oxidative stress in animals by modifying the antioxidant capacity and may alter the thyroid homeostasis. Therefore, hypothyroidism may affect the toxicity of arsenate. In order to test this hypothesis, zebrafish (Danio rerio) were made hypothyroid by exposure to perchlorate, and toxicity of arsenate in hypothyroid and euthyroid fish was compared. The endpoints were LC50 and thyroid histopathology. Additionally, the recovery of thyroid histopathological indices after cessation of perchlorate exposure was determined. The current study showed that 96 h LC50 of perchlorate anion and arsenate ion to juveniles fish (37 day post-fertilization) were 2532 and 56 mg l(-1), respectively. In addition, hypothyroid fish were more sensitive to arsenate, with a 96 h LC50 of 43 mg l(-1). Growth rates were also significantly retarded by perchlorate exposure. After cessation of perchlorate exposure, there was recovery of thyroid histopathology in terms of epithelial cell height, but not colloid area or growth rate. In conclusion, perchlorate enhances arsenate toxicity to juvenile zebrafish, and the rate of thyroid recovery after cessation of perchlorate exposure depends on the endpoints examined. 相似文献
906.
Lagmay AM Tengonciang AM Rodolfo RS Soria JL Baliatan EG Paguican ER Ong JB Lapus MR Fernandez DF Quimba ZP Uichanco CL 《Disasters》2008,32(3):416-433
A rockslide-debris avalanche destroyed the remote village of Guinsaugon in Southern Leyte, Philippines, on 17 February 2006. Although search and rescue procedures were implemented immediately, the scale of the landslide and a lack of information about its nature resulted in unfocused and imprecise efforts in the early days of the operation. Technical support was only introduced five days after the event, provided by a team of volunteer geologists, geophysicists, and meteorologists. By the time search and rescue operations were transferred to specific target sites, however, the chances of finding survivors trapped under the rubble had diminished. In such critical situations, speed, accuracy, and the maximum appropriation of resources are crucial. We emphasise here the need for a systematic and technically informed approach to search and rescue missions in large-scale landslide disaster contexts, and the formulation of better disaster management policies in general. Standard procedures must be developed and enforced to improve how civil authorities respond to natural calamities. 相似文献
907.
Macedo-Sousa JA Gerhardt A Brett CM Nogueira AJ Soares AM 《Environmental pollution (Barking, Essex : 1987)》2008,156(3):966-973
The drainage of abandoned mines leads to several ecological problems, particularly the acidification of surface freshwater systems and heavy metal contamination. In order to study the possibility of using the behavioural early warning responses of Portuguese indigenous benthic invertebrates to detect an acute short-term pulse of Acid Mine Drainage (AMD), experiments with the Multispecies Freshwater Biomonitor MFB™ were performed and locomotion and ventilation were measured as endpoints. AMD was collected from the “São Domingos” mine (Southeast Portugal) and the following species were selected: Echinogammarus meridionalis (Pinkster, 1973), Hydropsyche pellucidula (Curtis, 1834) and Choroterpes picteti (Eaton, 1870). For simulating the pulsed exposure, AMD was added to river water where invertebrates were collected and pH was lowered until reaching 3.5. The effects of H+ and heavy metals were discriminated using HCl positive controls. In addition to behaviour, mortality was registered. E. meridionalis was the most sensitive species in terms of mortality and behavioural endpoints, followed by C. picteti and H. pellucidula. E. meridionalis early warning responses consisted of increased locomotion with subsequent increase in ventilation, whereas for C. picteti only an increase in locomotion was observed. H. pellucidula showed no early warning responses. This work demonstrates the suitableness of using benthic invertebrates' behavioural early warning responses for detecting spikes of pollutants like AMD. 相似文献
908.
909.
To provide additional evidence that several halogenated organic compounds (HOCs) found in environmental samples are natural and not industrially produced, we analyzed an archived whale oil sample collected in 1921 from the last voyage of the whaling ship Charles W. Morgan. This sample, which pre-dates large-scale industrial manufacture of HOCs, contained two methoxylated polybrominated diphenyl ethers (MeO-PBDEs), five halogenated methyl bipyrroles (MBPs), one halogenated dimethyl bipyrrole (DMBP), and tentatively one dimethoxylated polybrominated biphenyl (diMeO-PBB). This result indicates, at least in part, a natural source of the latter compounds. 相似文献
910.
Aquifer sediments collected via split-spoon sampling in two new groundwater wells in the 200-UP-1 operable unit at the Hanford Site were characterized and showed typical Ringold Unit E Formation properties dominated by gravel and sand. High iron-oxide content in Fe oxide/clay coatings caused the highest U(VI) adsorption as quantified by batch K(d) values, indicating iron oxides are the key solid adsorbent in the 200-UP-1 sediments that affect U(VI) fate and mobility. Even though U(VI) adsorption on the gravel-sized fraction of the sediments is considered to be negligible, careful characterization should be conducted to determine U(VI) adsorption on gravel, because of presence of Fe oxides coatings and diffusion-controlled adsorption into the gravel particles' interior surfaces. A linear adsorption isotherm was observed up to 10(-6) M (238 microg/L) of total U(VI) concentration in batch U(VI) adsorption tests with varying total U(VI) concentrations in spiked groundwater. U(VI) adsorption decreased with increasing concentrations of dissolved carbonate, because strong anionic aqueous uranium-carbonate complexes formed at high pH and high alkalinity conditions. Noticeable uranium desorption hysteresis was observed in a flow-through column experiment, suggesting that desorption K(d) values for aged uranium-contaminated sediments at the Hanford Site can be larger than adsorption K(d) values determined in short-term laboratory experiments and slow uranium release from contaminated sediments into the groundwater is expected. 相似文献