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121.
Alan J. Hoffman Stanley F. Sleva William M. Cox 《Journal of the Air & Waste Management Association (1995)》2013,63(7):704-707
The National Ambient Air Quality Monitoring Program is carried out by state and local air pollution control agencies in support of their State Implementation Plans (SIP’s). The current EPA regulations which specify the characteristics of these state monitoring programs are undergoing change as a result of a comprehensive review by an independent work group. These revised regulations, which are described in the paper, are intended to improve the quality, timeliness, and usability of the data generated by the states for all data users. In addition, the revised regulations seek to bring about; (a) national consistency in monitoring site locations through standardized siting procedures; (b) improved network operations by means of a minimum quality assurance program; (c) reduced network inflexibility through an annual network review process; and (d) reduced data reporting through changed data reporting procedures. 相似文献
122.
William M. Cox Jon Clark 《Journal of the Air & Waste Management Association (1995)》2013,63(7):762-766
Data on dally maximum ozone concentrations measured at ambient air monitoring stations operated by state and local air pollution control agencies in the Eastern United States were analyzed using principal factor analysis. Four orthogonal factors representing O3 formation potentials were derived using the statistical package SPSS; these factors accounted for over two-thirds of the variations in 1978 summer O3 levels at 21 urban-oriented stations. The analysis confirmed that O3 variations are similar among stations within defined geographical areas; this confirmation supports the widely held theory that ambient O3 formations are reglonwlde. The analysis suggested that trends analysis for determining general progress in improving O3 air quality should be based on aggregate statistics from clusters of monitors rather than from a single monitoring station within areas associated with the derived factors. 相似文献
123.
Managing Baltic Sea fisheries under contrasting production and predation regimes: ecosystem model analyses 总被引:1,自引:0,他引:1
Based on an earlier published ecosystem model, we have explored possible effects of different management scenarios for the Baltic Sea. The scenarios include an oligotrophication of the system, a drastic increase in the number of seals, and changes in the fishery management. From these simulations we conclude that fisheries, seals, and eutrophication all have strong and interacting impacts on the ecosystem. These interactions call for integrated management. The modeling highlights the potential for conflicts among management mandates such as flourishing fisheries, rebuilt seal populations, and substantially reduced eutrophication. The results also suggest that fisheries management reference points have to be adjusted in response to changes in the presence of natural predators or ecosystem productivity. 相似文献
124.
125.
These days almost any construction plan gives rise to environmental, economic, and other concerns. In November 1977, the EPA funded a $9,000 two-day seminar at the University City Science Center in Philadelphia to examine the possible merits of Environmental Mediation as a procedure. The study materials supplied in advance contained eight cases for discussion. Case 5B was not one of them and was not prepared by federal officials. Though the situation described in Case 5B dates from 165 BC it is, coincidentally, in the same style and format (situation, problems, possible options) as the other eight cases of current vintage.However, there is one important difference. While the necessary permits for a proposed refinery at Portsmouth, Virginia (Case 2), or for conversion of VEPCO's power plant at Yorktown, Virginia from oil to coal (Case 3), or the Trexler, Pennsylvania, Lake Project (Case 7), may be held up forever, the aqueduct in Case 5B was built and performed its intended function well. 相似文献
126.
Robert E. Cox 《补救:环境净化治理成本、技术与工艺杂志》1995,5(2):29-39
Enhanced methods of in-situ remediation based on patented technology involving fluid injection with vacuum extraction have been used successfully at the Sand Creek Superfund Site in Commerce City, Colorado. Approximately 177,000 pounds of volatile organic compounds (VOCs) were removed from the subsurface in six months, two months ahead of schedule. Remediation goals were achieved on this thermally enhanced soil vapor extraction project by using vertical and horizontal wells interchangeably in vacuum or pressure service for vapor extraction, dual vacuum extraction, heated vapor reinjection, and air sparging. Although VOCs consisted of mixed chlorinated and petroleum hydrocarbons, the petroleum hydrocarbons, some in the form of nonaqueous phase liquids, had not been fully characterized. This article examines the evolution of the remedial design from that conceptualized in the Record of Decision (ROD) of the U.S. EPA, presents the rationale for the selection of alternative system components, and provides a cost analysis of the selected remedial technology, with comparisons to that of alternatives considered for use at Sand Creek. 相似文献
127.
Amniocentesis was performed because of a fetal abdominal wall defect, and a 45,X karyotype was obtained. A near-normal male infant with no features of Turner syndrome was delivered. The karyotype of the infant was 45,X/46,X, dic(Y)(q11), with each of the cell lines present in approximately 50 per cent of the lymphocytes and fibroblasts examined. 相似文献
128.
129.
Autotoxic effects of essential oils on photosynthesis in parsley, parsnip, and rough lemon 总被引:3,自引:0,他引:3
Summary. Many plant species contain essential oils with allelochemical properties, yet the extent to which these same chemicals can be autotoxic is unclear. In this study, we tested the toxicity of several essential oil components to three species that produce them—Pastinaca sativa and Petroselinum crispum (Apiaceae), and Citrus jambhiri (Rutaceae). The effects of exogenous application of small amounts of essential oil components to the surface of foliage, followed by a pinprick to allow entry into the leaf, were monitored by chlorophyll fluorescence imaging. Rapid and spatially extensive declines in photosynthetic capacity were detected within 200 s. The most toxic constituents were monoterpenes. Two sesquiterpenes, caryophyllene and farnesene, and the phenylpropanoid myristicin, by comparison, were not toxic. Autotoxicity of endogenous essential oil was investigated by slicing through containment structures (glands or tubes); significant toxicity, manifested by reduced photosynthetic activity, was observed in all three species but was most pronounced in P. sativa and P. crispum, both of which possess oil tubes. 相似文献
130.
Filamentous cyanophytes containing phycourobilin and in symbiosis with sponges and an ascidian of coral reefs 总被引:2,自引:0,他引:2
A study was made of the ultrastructure and pigment composition of filamentous cyanophytes living in symbiosis with several sponges and a colonial didemnid ascidian collected from the southern end of the Great Barrier Reef, Australia, between 1983 and 1986. The sponges were Dysidea herbacea Keller and several other encrusting sponges which have not been identified; the ascidian was Trididemnum miniatum Kott (1977). The cyanophyte Oscillatoria spongeliae (Shultz) Hauck was identified as the symbiont of several of the sponges, including D. herbacea. Two other unidentified Oscillatoria species were found in a bristly papillate sponge and in T. miniatum. Chlorophyll a, alone, was present in all the symbionts with the exception of T. miniatum, which contained the cosymbiont Prochloron and where chlorophyll b was also present. Two phycoerythrins were isolated by chromatography and chromatofocusing. Both resembled C-phycoerythrin, but one of the two carried the chromophore phycourobilin as well as phycoerythrobilin possibly on both the and subunits, which had apparent molecular masses of 18 and 20 kdaltons. No subunit was present. Ultrastructurally, the three Oscillatoria species were distinguished by an unusual type of parallel, longitudinal, thylakoid organisation; the arrangement was different in detail in each species. 相似文献