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41.
Drake Hocking Peter Kuchar James A. Plambeck Roy A. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(2):133-137
Gold smelters near Yellowknife in Canada's Northwest Territories have emitted large quantities of sulfur dioxide and arsenic since inception of roasting in 1941. Although particulate wastes are well contained by baghouse fitters in the one remaining operating smelter, significant gaseous emissions continue. Soil and vegetation were sampled at 52 sites over an area of about 40 km radius from the source. Plant ecology was studied at 43 of those sites. After preliminary multi-element screening that indicated only arsenic was a serious persistent contaminant, x-ray fluorescence was used to measure arsenic content in sampled materials. The plant ecology data were synthesized into an Index of Vitality with numerical ratings of pertinent factors. In the marginal forests and rocky outcrops of the area, indicator species of vegetation permitted a division into zones of severe, moderate, mild, or no impact in order of increasing distance from the current center of emissions. Severe impact, including killing of trees, is local only. Analyses of foliage indicate little uptake of arsenic which, together with the presence of S02 symptoms, point to S02 as the main factor causing decline of vegetation. A separate study, abstracted here, supports this view by providing data that show a frequency of at least 2 significant fumigation episodes per growing season. Soil analyses indicate extremely high arsenic contamination near the stack. A monotonie pattern of dispersion yielded a function explainable in terms of rapid condensation of gaseous emissions. The relationship of arsenic in surface soil and vegetation to distance is approximately an inverse square. 相似文献
42.
S. Witz M. Smith M. Shu A. B. Moore 《Journal of the Air & Waste Management Association (1995)》2013,63(3):276-278
Air monitoring In the San Francisco Bay Area was carried out to measure outdoor community air concentrations of poly cyclic aromatic hydrocarbons (PAH) and mutagenlc activity (mutagenlclty) In participate organic matter (POM). Monitoring began In 1979 and Is currently conducted at six stations. PAH and mutagenlclty tests were performed on organic extracts prepared from high volume (hl-vol) filters composited every four months, by meteorological season. PAH were determined by high pressure liquid chromatography (HPLC) with fluorescence and ultraviolet detection. Mutagenlclty was measured In the Ames Salmonella bloas-say using strain TA98 with and without metabolic activation. The nine-year mean concentration of benzo(a)pyrene (BaP) was 0.4 ng/m3. The mutagenlcfty of this amount of BaP accounted for only about 0.2% of the observed mutagenicity In POM and other measured PAH accounted for even less. Concentrations of PAH and mutagenlclty were three to nine times higher during the winter than during other seasons. Year-to-year wintertime trends In several PAH were also seen. Early In the 1980s, winter concentrations of BaP and benzo (g,h,i)perylene Increased. However since the mld-1980’s, their concentrations have fallen. The decrease In PAH concentrations may be the result of an Increasing proportion of vehicles with relatively low organic emissions. In contrast to PAH, mutagenlcfty did not show significant year-to-year time trends. 相似文献
43.
Charles H. Darvin Lyndon S. Cox Daryl Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(3):339-344
ABSTRACT During recent years, greater emphasis has been placed on the control of particulate emissions from painting operations. This has gained more importance as more is learned about the potential release of toxic metals to the atmosphere from painting operations. This has led to queries about the efficiency of various painting arrestor systems to reduce particulate discharges to the atmosphere. Even more important is the capability of the arrestor systems to control PM10 emissions. In 1995, the U.S. Environmental Protection Agency initiated a study to evaluate various dry paint overspray arrestor systems. This study was designed to evaluate not only the total emissions control capability of the arrestor but also the PM10 control capability of the various system designs. Paint overspray arrestor systems using five different filtration concepts or materials were selected. They include systems constructed of fiberglass, paper, Styrofoam, and cardboard materials. These systems used filtration techniques incorporating the following filtration phenomena and designs: cyclone, baffle, bag systems, and mesh systems. The testing used an optical particle counting procedure to determine the concentration of particles of a given size fraction to penetrate a test arrestor system. The results of the testing indicated that there are significant differences in the efficiency of the tested system designs to capture and retain PM10. This paper summarizes the results of the research conducted to determine the capability of the arrestor systems to capture particulate of sizes down to approximately 1 μm in surface diameter. 相似文献
44.
Paul E. Smith 《Journal of the Air & Waste Management Association (1995)》2013,63(10):876-880
The purpose of this investigation was to determine the effects of meteorological conditions and specific air pollutants on the viability of airborne algae and protozoa. Such investigations will be of interest to medical researchers because these organisms are the source of many allergies. The three air pollutants that were continuously measured and recorded were sulfur, hydrocarbons, and particulate maiter. During the experiment, 25 different species of algae and 19 species of protozoa were collected from the atmosphere and cultured at the Westinghouse Environmental Station Laboratory in Raleigh, North Carolina. The algae and protozoa were collected over a one-year period (Jan-Dec 1971) by using a sequential sampler that moved air through a membrane filter at the rate of 15 ft3/hr. Every two hours a new filter was sequentially moved in to replace the old one. The results indicated a relationship between wind speed, wind direction, temperature, dew-point, particulate matter, barometric pressure, and rainfall to the percent frequency of positive culture tubes and number of cells/ft3 of air. Further studies are necessary to determine the interrelationships between the physical and chemical character of various air masses and their effect on the survival of algae and protozoa. 相似文献
45.
Rufus Edwards Kirk R. Smith Brent Kirby Tracy Allen Charles D. Litton Susanne Hering 《Journal of the Air & Waste Management Association (1995)》2013,63(6):789-799
Abstract In developing countries, high levels of particle pollution from the use of coal and biomass fuels for household cooking and heating are a major cause of ill health and premature mortality. The cost and complexity of existing monitoring equipment, combined with the need to sample many locations, make routine quantification of household particle pollution levels difficult. Recent advances in technology, however, have enabled the development of a small, portable, data-logging particle monitor modified from commercial smoke alarm technology that can meet the needs of surveys in the developing world at reasonable cost. Laboratory comparisons of a prototype particle monitor developed at the University of California at Berkeley (UCB) with gravi-metric filters, a tapered element oscillating microbalance, and a TSI DustTrak to quantify the UCB particle monitor response as a function of both concentration and particle size and to examine sensor response in relation to changes in temperature, relative humidity, and elevation are presented here. UCB particle monitors showed good linearity in response to different concentrations of laboratory-generated oleic acid aerosols with a coarse (mass median diameter, 2.1 µm) and fine (mass median diameter, 0.27–0.42 µm) size distributions (average r2 = 0.997 ± 0.005). The photoelectric and ionization chamber showed a wide range of responses based on particle size and, thus, require calibration with the aerosol of interest. The ionization chamber was five times more sensitive to fine rather than coarse particles, whereas the photoelectric chamber was five times more sensitive to coarse than fine. The ratio of the response between the two sensors has the potential for mass calibration of individual data points based on estimated parameters of the size distribution. The results demonstrate the significant potential of this monitor, which will facilitate the evaluation of interventions (improved fuels, stoves, and ventilation) on indoor air pollution levels and research on the impacts of indoor particle levels on health in developing countries. 相似文献
46.
Corals are the primary reef-building organisms, therefore it is key to understand their recruitment patterns for effective reef management. Coral recruitment rates and juvenile coral abundance were recorded in the Wakatobi National Marine Park, Indonesia, on two reefs (Sampela and Hoga) with different levels of environmental degradation (12.5 vs. 44 % coral cover with high and low sedimentation rates, respectively) to examine consistencies in recruitment patterns between years and seasons. Recruitment was measured on multiple panels at two sites on each reef (6–7 m depth) and cleared areas of natural reef. Although coral recruitment was twofold higher in 2008–2009 than in 2007–2008, and seasonal differences were identified, consistent significant differences in recruitment rates were found between the two reefs even though they are separated by only ~1.5 km. Recruitment rates and juvenile abundance were lower on the more degraded reef. These patterns are likely a consequence of differential pre- and post-settlement mortality as a result of the high sedimentation rates and degraded conditions and possibly reduced larval supply. 相似文献
47.
The threat-sensitivity hypothesis predicts that prey individuals will increase antipredator behaviors as apparent predator risk increases. An implicit assumption of the threat-sensitivity hypothesis is that predator risk is additive. In other words, all characteristics of a predator that indicate risk should contribute in an additive way to determine the degree of risk-sensitive behavior. We tested this assumption in the laboratory by presenting live predators (green sunfish, Lepomis cyanellus) to groups of western mosquitofish (Gambusia affinis). We examined effects of predator diet, hunger level, and size on predator avoidance and inspection behavior of mosquitofish. Both predator diet and predator hunger level were significant and additive determinants of distance maintained from a predator, resulting in a graded response to combinations of these predator cues. In contrast, whereas predator diet was the most important determinant of general avoidance distances, predator hunger level was more important in determining mosquitofish vertical distribution and inspection behavior. Thus, the relationship between predator cue and the antipredator behavior that it elicits is dependent on which cues and behaviors are examined. Our data suggest that during risky behaviors, such as predator inspection, mosquitofish rely mainly on visual cues (behavior differences between hungry and satiated predators), whereas general avoidance behavior is determined by additive responses from visual and chemical cues. 相似文献
48.
Long-Term Relationship between Phosphorus Inputs and Wetland Phosphorus Concentrations in a Northern Everglades Marsh 总被引:3,自引:0,他引:3
Assessments of long-term relationships between changes innutrient inputs and wetland nutrient concentrations can becomplicated by fluctuations in other environmental factors aswell as by problems typical of long-term monitoring data.Consequently, statistical analysisof these types of data sets requirescareful consideration of environmental covariates, potentialbiases in the monitoring design, and irregularities caused bychanges in field sampling protocols. We evaluated therelationship between anthropogenic phosphorus (P) inputs andwater-column total P (TP) concentrations in a northernEverglades marsh by statistically analyzing available datacollected from several sampling programs over the past 20 years(1978–1997). Canal inputs of agricultural runoff contributemost of the P to the marsh and have produced a zone ofenrichment within the marsh during the past few decades.Regression analyses showed that both canal and marsh TPconcentrations increased during the 1980s and then decreased inthe 1990s. However, the statistical relationship between canal Pinputs and marsh TP, while significant, generally was weakexcept for marsh locations adjacent to the canal. Strongerrelationships existed between marsh TP and hydrologic parameterssuch as marsh water depth, which is controlled by changes inweather patterns and marsh management. In particular, dryconditions during the 1980s may have contributed to observedincreases in marsh P concentrations and the movement of a P`front' further into the marsh. Higher rainfall and water depthsand agricultural best management programs initiated during the1990s have been associated with reduced P concentrations incanal waters entering the marsh. While it is anticipated thatthis reduction eventually will result in lower marsh TPconcentrations, this effect is not yet evident, possibly due tointernal loading of P from enriched marsh soils. Our findingsillustrate some of the environmental factors that can complicateattempts to develop empirical relationships between P inputs andwetland P concentrations and to use such relationships to forecast changesin marsh concentrations based on past monitoring data alone. 相似文献
49.
In order to take account of the congestion externalities associated with increased use intensity during a given period at a low density recreational resource, it is necessary to determine the effects of alternative use levels on the expected quality of each individual's experience. This paper describes a simulation model for wilderness recreation designed to provide such measures. In order to illustrate the model it is applied to the Spanish Peaks Areas in Montana. 相似文献
50.
Jimmie C. Oxley James L. Smith Carolyn Higgins Patrick Bowden Jesse Moran Joe Brady Carol E. Aziz Evan Cox 《Journal of environmental management》2009,90(11):3629-3634
When an explosive detonates or a propellant or flare burns, consumption of the energetic filler should be complete but rarely is, especially in the presence of large amounts of non-combustible materials. Herein we examine three types of perchlorate-containing devices to estimate their potential as sources of contamination in their normal mode of functioning. Road flares, rocket propellants and ammonium nitrate (AN) emulsion explosives are potentially significant anthropogenic sources of perchlorate contamination. This laboratory evaluated perchlorate residue from burning of flares and propellants as well as detonations of ammonium nitrate emulsion explosives. Residual perchlorate in commercial products ranged from 0.094 mg perchlorate per gram material (flares) to 0.012 mg perchlorate per gram material (AN emulsion explosives). The rocket propellant formulations, prepared in this laboratory, generated 0.014 mg of perchlorate residue per gram of material. 相似文献