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841.
842.
Liem T. Tran C. Gregory Knight Robert V. O'Neill Elizabeth R. Smith Kurt H. Riitters James Wickham 《Environmental management》2001,29(6):845-859
A fuzzy decision analysis method for integrating ecological indicators was developed. This was a combination of a fuzzy ranking method and the analytic hierarchy process (AHP). The method was capable of ranking ecosystems in terms of environmental conditions and suggesting cumulative impacts across a large region. Using data on land cover, population, roads, streams, air pollution, and topography of the Mid-Atlantic region, we were able to point out areas that were in relatively poor condition and/or vulnerable to future deterioration. The method offered an easy and comprehensive way to combine the strengths of fuzzy set theory and the AHP for ecological assessment. Furthermore, the suggested method can serve as a building block for the evaluation of environmental policies. 相似文献
843.
Ashlee E. Walker Robert E. Holman Ross B. Leidy 《Journal of the American Water Resources Association》2000,36(1):67-74
ABSTRACT: Studies were conducted to analyze the presence of 11 pesticide residues in 12 surface waters in the Piedmont and coastal plain regions of North Carolina. Samples were assayed using enzyme‐linked immunosorbent assays (ELISAs). All ELISA results of one part per billion (ppb, μg/L) or greater were confirmed using gas chromatography/mass spectrometry (GCIMS). ELISA detection limits were approximately an order of magnitude higher than GCJMS methods. Of the 5,035 analytical results from 742 surface water samples, atrazine was detected in approximately 45 percent of the samples, five of which were at or above the Maximum Contaminant Level (MCL) of 3‐ppb. Metolachlor was detected in 64 percent of the samples. Aldicarb, 2,4‐D, chlorpyrifos, and chlorothalonil were also detected, and each was found in less than 12 percent of the samples. The remaining pesticides, including carbaryl, acetochior, methomyl, carbofuran, and alachlor, were not detected during the study period. 相似文献
844.
Per Angelstam Marine Elbakidze Robert Axelsson Malcolm Dixelius Johan Törnblom 《Ambio》2013,42(2):116-128
There are multiple challenges regarding use and governance of landscapes’ goods, functions and intangible values for ecosystem health and human well-being. One group of challenges is to measure and assess principal sustainability dimensions through performance targets, so stakeholders have transparent information about states and trends. Another group is to develop adaptive governance at multiple levels, and management of larger geographical areas across scales. Addressing these challenges, we present a framework for transdisciplinary research using multiple landscapes as place-based case studies that integrates multiple research disciplines and non-academic actors: (1) identify a suite of landscapes, and for each (2) review landscape history, (3) map stakeholders, use and non-use values, products and land use, (4) analyze institutions, policies and the system of governance, (5) measure ecological, economic, social and cultural sustainability, (6) assess sustainability dimensions and governance, and finally (7) make comparisons and synthesize. Collaboration, communication and dissemination are additional core features. We discuss barriers bridges and bridges for applying this approach. 相似文献
845.
Eylon Shamir Thomas L. Thompson Martin M. Karpiscak Robert J. Freitas Jeffrey Zauderer 《Journal of the American Water Resources Association》2001,37(2):315-325
ABSTRACT: A free water surface (FWS) constructed wetland was installed at a dairy in Glendale, Arizona, to study the potential of such a wetland to remove nitrogen (N) from wastewater. The study objectives were: (1) to determine N removal from the wastewater, and (2) to evaluate N accumulation in soil and plant tissues. The system consisted of eight cells (70 × 9 × 1.5 m) planted with Typha domingensis, Scirpus validus, and Phragmites australis. The four cells in series were lined with plastic, and the four cells in a parallel series were lined with clay. Cells received approximately 180 m3/d of partially treated dairy effluent. Plant tissues and soil samples were collected above and below ground from 24 locations during one year. Total N removal from wastewater was about 17 percent. Clay‐lined cells accumulated more N in the soil and less N in plant biomass compared with plastic lined cells. Plant biomass accounted for approximately 60 percent of total N accumulated in cells with dense plant communities. Ninety percent of accumulated soil N was organic. Total N accumulated in soil reached a maximum (1,100 mg/kg) eight months after the introduction of wastewater. 相似文献
846.
Walter J. Hamming Robert D. Macphee James R. Taylor 《Journal of the Air & Waste Management Association (1995)》2013,63(1):7-16
Sampling for nitrogen and sulfur dioxides was initiated at several National Air Sampling Network stations in 1959 using a sampler developed for that purpose. In 1961 the Gas Sampling Network was expanded to its maximum of 49 stations. Sampling equipment and collecting solutions are supplied and chemical analyses performed by the network laboratories. Sampling and analysis procedures are described briefly. Average and maximum 24-hour concentrations of nitrogen dioxide and sulfur dioxide observed at 48 stations during 1961-1963 are presented. 相似文献
847.
Charles H. Worsham Robert B. Long John P. Longwell 《Journal of the Air & Waste Management Association (1995)》2013,63(3):135-140
Present methods for the determination of carbon monoxide are discussed including indicator tubes, the iodine pentoxide reaction and measurement by gas chromatography. In the gas chromatographic method an air sample is separated on a gas-solid chromatogra-phic column and the separated CO is converted to methane by hydrogenation at elevated temperature. The separated CO, in the form of methane, is passed into a hydrogen flame detector and measured. The conversion from CO to methane allows the use of a sensitive ionization detector in place of the thermal conductivity cell which is insufficiently sensitive for the measurement of trace amounts of CO. The optimum operating conditions are discussed. It is possible to determine one ppm CO in air. The iodine pentoxide reaction with CO has been combined with electrometric measurement. The iodine liberated is passed into a Ditte cell and the current generated is measured by an electrometerrecorder combination. This method is continuously direct reading with a permanent record. It is suitable for the continuous routine analysis of one ppm CO. 相似文献
848.
849.
Gordon C. Page Robert M. Bethea 《Journal of the Air & Waste Management Association (1995)》2013,63(5):372-373
A combined water scrubber-impinger was used to control lint cleaner effluent from machine-stripped short staple (11/16-13/16 in.) cotton because of its high efficiency and low pressure drop. The 8 × 4 × 4 ft rectangular scrubber could handle a maximum of 8000 CFM entering air at 80°F, 20% relative humidity and 0.7 g particulates/m3 with a 1-sec residence time at a maximum pressure drop of 0.5 in. of water across the chamber. Water to the chamber’s 6 doublespray and 2 single-spray nozzle taps was supplied from recycle and makeup sources at pressures of 7.5–30 psig with total flows of 21.8–31.1 gpm depending on number of nozzle taps in use. These sprays effectively wetted the particulate- laden air and provided enough water to wash the collected particulate matter down the chamber walls. The four WR-10 nozzles used at the base of the scrubbing chamber provided fine conical spray patterns co-current with the air flow. The two sets of four F-20 nozzles used in the center portion of the chamber provided coarse flat sheet sprays perpendicular to the air flow path. Two large TR-50 nozzles at the top of the chamber provided the necessary coarse conical sprays to wash the collected particulates down the chamber wall to the trash-water separator below. Water flows through the nozzles were determined from pressure readings at each tap. Chamber pressure drop was determined by 15° inclined manometer readings taken across the chamber at the locations where the air inlet and outlet mean square velocities occurred. 相似文献
850.
Morton Corn Robert T. Cheng 《Journal of the Air & Waste Management Association (1995)》2013,63(11):870-875
A laboratory study was conducted of the heterogeneous catalysis of sulfur dioxide at ppm concentrations in air by insoluble particles of CaCO2, V2O5, Fe203, flyash from a coal-burning power plant, MnCO2, activated carbon, and suspended particulate matter from urban air. The investigalion was performed by utilizing a new technique for aerosol stabilization which consists of depositing the aerosol on Teflon beads in a fluidized bed. The Teflon beads with deposited aerosol particles were then packed into a flow reactor. Progress of the chemical reaction of SO2 with deposited particles was continuously monitored by determining the SO2 concentrations in the reactor effluent with a microcoulometer. In this investigation, CaCOg, V2O5, and flyash were essentially inert to SO2 at room temperature. Fe2O3, activated carbon, MnO2, and suspended particulate matter from urban air sorbed SO2 from air streams with up to 14.4 ppm SO2 in air. Evidence is presented which suggests that a substantial part of the sorbed SO2 was physically adsorbed. Bioassay procedures which utilize pulmonary flow resistance changes in guinea pigs to monitor response to inhaled SO2-aerosol mixtures in air have indicated the weak or non-potentiating capacity of insoluble aerosols as contrasted to soluble aerosols. Potentiating response of an aerosol appears to be strongly associated with reaction of SO2 in a water droplet containing aerosol ions and not with physically adsorbed SO2 on an insoluble aerosol. 相似文献