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51.
52.
We monitored nest boxes during 1997–1999 at Acadia National Park, Mt. Desert Island, ME and at an old-field site in Orono,
ME to determine mercury (Hg) uptake in tree swallow (Tachycineta bicolor) eggs, tissues, and food boluses. Also, in 1998–1999 we monitored nest boxes at Grove Pond and Plow Shop Pond at a U.S. Environmental
Protection Agency Superfund site in Ayer, MA. We recorded breeding success at all locations. On average among locations, total
mercury (THg) biomagnified 2 to 4-fold from food to eggs and 9 to 18-fold from food to feathers. These are minimum values
because the proportion of transferable methyl mercury (MeHg) of the THg in insects varies (i.e., 35%–95% of THg) in food boluses.
THg was highest in food boluses at Aunt Betty Pond at Acadia, whereas THg in eggs was highest at the Superfund site. A few
eggs from nests at each of these locations exceeded the threshold (i.e., 800–1,000 ng/g, wet wt.) of embryotoxicity established
for Hg. Hatching success was 88.9% to 100% among locations, but five eggs failed to hatch from 4 of the 11 clutches in which
an egg exceeded this threshold. MeHg in feathers was highest in tree swallows at Aunt Betty Pond and the concentration of
THg in bodies was related to the concentration in feathers. Transfer of an average of 80%–92% of the Hg in bodies to feathers
may have enhanced nestling survival. Residues of Hg in tissues of tree swallows in the Northeast seem higher than those of
the Midwest. 相似文献
53.
This paper was one of several presented at the Workshop on Air Pollution Control in Portland, Oregon, on May 6, 1968. The Workshop was sponsored by the Manufacturing Chemists Association and the Chemical Industry Council of the Pacific Northwest in cooperation with the Association of Oregon Industries, Association of Washington Industries, and the Environmental Committee of the Portland Chamber of Commerce. While many of the papers were of localized interest, this paper speaks to anyone designing air pollution control systems. 相似文献
54.
J. O. Ivie M. D. Thomas O. C. Taylor C. Ray Thompson W. M. Dugger JR. B. L. Richards 《Journal of the Air & Waste Management Association (1995)》2013,63(8):355-359
A discussion of the methods used to determine the most economic design of chimney for a new thermal power station or large industrial plant is presented, with the objective that ground level concentration of pollutants will be kept at a minimum. Attention is paid to the geography and climatology of the site, with special reference to the frequency and height of inversions and the prevailing wind direction and speed. A method is illustrated in using a large thermal power station as an example. The maximum sulfur dioxide concentrations at ground level are computed for several chimney heights and gas exit velocities. The values of these sulfur dioxide concentrations, the capital cost of the chimney, the pumping costs, and the gas pressures within the chimney are considered in selecting a suitable chimney height and a gas exit velocity which will meet most economically the stated objective. The paper deals primarily with chimneys for industrial or power boiler plant of maximum continuous rating greater than 450 million Btu/hr (about 450,000 lbs of steam/hr), or to chimneys serving furnaces burning fuel at a maximum rate greater than 50,000 lbs/hr of coal, or 80,000 lbs/hr of oil. For chimneys serving plant with smaller heat inputs, chimney selection by reference to Clean Air Act 1956, Memorandum on Chimney Heights is suggested. 相似文献
55.
56.
Cheese, Tourists, and Red Pandas in the Nepal Himalayas 总被引:3,自引:0,他引:3
57.
58.
We assessed relationships between the extent to which farmers reported exposure to relevant information and their attitudes
towards, knowledge about, and degree of adoption of riparian management strategies. We also examined associations between
knowledge of, or receipt of, financial assistance for riparian fencing/planting and intentions for and extent of adoption
of this strategy. A mail survey of 718 pastoral farmers in Otago and Southland in New Zealand [294 surveys returned (41%)]
yielded 279 usable questionnaires. Indices were developed to reflect range and frequency of information use and range of practices
adopted. Attitudes were measured using Likert-type responses to 11 statements, and knowledge as a score on a ten-question
true/false test. Positive relationships between information and the three main response variables (attitude, knowledge, and
adoption) were weak but significant and systematic. These associations remained significant when important demographic and
farm characteristics were taken into account. Informed farmers were more likely to report intentions to carry out riparian
fencing or planting within the next year. Farmers who were aware that funding was available were also more likely to state
this intention, independent of information level. The reported extent to which waterways had been fenced to exclude stock
was related to receipt of funding, but not to information level. Financial factors were the most influential barrier preventing
adoption of permanent fencing. Our research shows a positive correlation between the receipt of information and funding and
the adoption of specific riparian management measures. 相似文献
59.
/ Arthropod communities from several habitats on and adjacent to the El Segundo dunes (Los Angeles County, CA) were sampled using pitfall and yellow pan traps to evaluate their possible use as indicators of restoration success. Communities were ordinated and clustered using correspondence analysis, detrended correspondence analysis, two-way indicator species analysis, and Ward's method of agglomerative clustering. The results showed high repeatability among replicates within any sampling arena that permits discrimination of (1) degraded and relatively undisturbed habitat, (2) different dune habitat types, and (3) annual change. Canonical correspondence analysis showed a significant effect of disturbance history on community composition that explained 5-20% of the variation. Replicates of pitfall and yellow pan traps on single sites clustered together reliably when species abundance was considered, whereas clusters using only species incidence did not group replicates as consistently. The broad taxonomic approach seems appropriate for habitat evaluation and monitoring of restoration projects as an alternative to assessments geared to single species or even single families. 相似文献
60.
The high degree of physical disturbance associated with conventional response options to oil spills in wetlands is driving
the investigation of alternative cleanup methodologies. In March 1995, a spill of gas condensate in a brackish marsh at Rockefeller
Wildlife Refuge in southwestern Louisiana was remediated through the use of in situ burning. An assessment of vegetation recovery
was initiated in three treatment marshes: (1) oil-impacted and burned, (2) oil impacted and unburned, and (3) a nonoiled unburned
reference. We compared percent cover, stem density, and biomass in the treatment marshes to define ecological recovery of
the marsh vegetation and soil hydrocarbon content to determine the efficacy of in situ burning as a cleanup technique. Burning
led to a rapid decrease in soil hydrocarbon concentrations in the impacted-and-burned marsh to background levels by the end
of the first growing season. Although a management fire accidentally burned the oil-impacted-and-unburned and reference marshes
in December 1995, stem density, live biomass, and total percent cover values in the oil-impacted-and-burned marsh were equivalent
to those in the other treatment marshes after three years. In addition, plant community composition within the oil-impacted-and-burned
marsh was similar to the codominant mix of the grasses Distichlis spicata (salt grass) and Spartina patens (wire grass) characteristic of the surrounding marsh after the same time period. Rapid recovery of the oil-impacted-and-unburned
marsh was likely due to lower initial hydrocarbon exposure. Water levels inundating the soil surface of this grass-dominated
marsh and the timing of the in situ burn early in the growing season were important factors contributing to the rapid recovery
of this wetland. The results of this in situ burn evaluation support the conclusion that burning, under the proper conditions,
can be relied upon as an effective cleanup response to hydrocarbon spills in herbaceous wetlands. 相似文献