خيارات البحث
النتائج 101 - 110 من 306
Degradation of aromatics and saturates in crude oil by soil enrichments
1981
Fedorak, P.M. | Westlake, D.W.S. (Alberta Univ., Edmonton (Canada). Dept. of Microbiology)
Soil was incubated in the presence of Prudhoe Bay crude oil at 20 deg C under shake-flask conditions. With the addition of N and P to the medium, the susceptibility of aromatic compounds to microbial degradation over an 11-day period was found to be: naphthalene approx. = 2-methylnaphthalene 1-methylnaphthalene dimethylnaphthalenes approx. = dibenzothiophene approx. = phenanthrene C(,3)-napthalenes methyl-phenanthrenes C(,2)-phenanthrenes. The n-alkanes and isoprenoids (pristane and phytane) were also extensively degraded during this time. The omission of N and P from the medium reduced the extent to which the culture degraded the n-alkanes but had little effect on the degradation of the aromatic fraction after a 27-day incubation period.
اظهر المزيد [+] اقل [-]Metal pollutants in agricultural soils and the St Louis urban rainfall anomaly
1981
Gatz, D.F. | Bartlett, J. (Illinois State Water Survey, Urbana (USA). Atmospheric Sciences Section) | Hassett, J.J.
The existence of a rainfall anomaly downwind of the St. Louis urban-industrial areas prompted a survey of area soils for elevated heavy metal concentrations. The goals of this work were to measure concentrations of Zn, Cd, and Pb, and to evaluate the role of the urban rainfall anomaly in their accumulation, in potentially-affected soils. Samples from three soil layers were collected from agricultural fields at 21 sites along two NE-SW transects. The samples were analyzed for pH, texture, cation exchange capacity, and total organic carbon, in addition to the three metals. The highest metal concentrations were observed near Granite City, Illinois, and coincided with an area of maximum Zn deposition in rain found in an earlier study. Only slight increases of the metals over background were found in the area of rainfall anomaly. Present rates of atmospheric deposition can account for these slightly elevated metal concentrations. However, the maximum concentrations found near Granity City cannot be accounted for by present atmospheric deposition rates. Other kinds of sources, or larger atmospheric deposition rates, perhaps during the operation of a local Zn smelter which closed about 1960, must have contributed.
اظهر المزيد [+] اقل [-]Chlorophyll reduction in western wheatgrass (Agropyron smithii Rydb.) exposed to sulfur dioxide
1981
Lauenroth, W.K. | Dodd, J.L. (Colorado State Univ., Fort Collins (USA). Natural Resource Ecology Lab.)
Leaching of metals from the A-horizon of a spruce forest soil
1981
Tyler, G. (Lund Univ. (Sweden). Dept. of Plant Ecology)
The study quantifies the amount of metals, (Na, K, Mg, Ca, Al, Fe, Mn, Ni, Cr, V, Cu, Zn, Cd, Pb) leached from the A-horizon of a podzolic spruce forest soil in southern Sweden during 2.5 yr, and offers statistical evidence of environmental conditions of importance to metal release. Considerable losses of Pb, Cr, Ni and V may occur from the A-horizon of forest soils under conditions favoring leaching of organic matter, Fe, and Al, i.e. during periods of comparably high soil temperature and moisture. Metals with a larger fraction present in exchangeable form (Na, Mg, Ca, Zn, Cd) are more susceptible to minor pH changes. An accelerated deposition or internal production of acidic matter therefore will reduce the retention times of these elements particularly.
اظهر المزيد [+] اقل [-]Amounts and relative significance of runoff types in the transport of nitrogen into a stream draining an agricultural watershed
1981
Sharpley, A.N. | Syers, J.K. (Massey Univ., Palmerston North (New Zealand). Dept. of Soil Science)
Groundwater resources
1981
Mandel, S. (Samuel) | Shiftan, Z. L.
Sulphur isotope ratios in water, air, soil and vegetation near Teepee Creek gas plant, Alberta [(Canada)]
1981
Krouse, H.R. | Case, J.W. (Calgary Univ., Alberta (Canada). Physics Dept.)
Baseline data relevant to assessing environmental impact of continued operation of the Teepee Creek gas plant or similar future industrial operations included S concentrations, pH of soil and water, and S isotope determinations. Concentrations evaluated the S loading while isotope determinations identified sources of environmental S. The industrial source was very enriched in ('34)S(delta('34)S=+24 0/00) while soil and vegetation were characterized by ('34)S depletions (delta('34)S values as low as-20 0/00 mean value near -8 0/00). Thus S isotope determinations provided an excellent tool for environmental assessment in the region. It was found that the following are the more significant observations: (1) Neither the pH data nor S isotope compositions of the water or soil samples reveal measurable S loading by the industrial operation. (2) The measured atmospheric SO('2) concentrations are well below permitted air quality standards. (3) Data from an atmospheric sampling array revealed that the directions of highest SO('2) concentrations did not correspond to the direction of the gas processing plant nor did high concentrations relate isotopically to the emissions. (4) In both soil and vegetation samples, increase of S concentration was identified isotopically with mineral layers in the sub-surface and not with the industrial operation. Thus it is concluded that S in the environment surrounding the Teepee Creek gas plant was dominated by sources other than the plant emissions.
اظهر المزيد [+] اقل [-]Atrazine residues in estuarine water and the aerial deposition of atrazine into Rhode River, Maryland [USA]
1981
Wu, T.L. (Smithsonian Institution, Edgewater, MD (USA). Chesapeake Bay Center for Environmental Studies)
Water samples from the Rhode River, an estuary situated on the western shore of the Chesapeake Bay, were analyzed for atrazine residues twice a week for 2 yr. Precipitation samples, which included dryfall, rainfall, and snowfall were collected with wide-mouth stainless steel collection pans situated about 20 m above ground in an open space. A total of 68 precipitation samples was collected from December 1976 to February 1979. Atrazine residues were detectable in estuarine water and in rainwater year-round. Atrazine residues in estuarine water were generally 6 to 190ng/l, atrazine residues in rainwater (bulk precipitation) were 3 to 2190ng/l. Atrazine residues in rainwater samples collected during the winter season (January to April 1977) were unexpectedly high (e.g. 3 to 970ng/l). The highest atrazine concentration of 2190ng/l was detected from a 0.76 cm rainfall event collected on May 19, 1977. Intermittent spraying operations of atrazine within the cornfields were generally done during May of each year. Rain samples collected during May of 1978 also showed higher atrazine residues than the rest of the 1978 growing season, but at levels much less than those detected in 1977 rainwater. Although high attrazine concentrations were detected in winter rainfall, these did not result in similarly higher atrazine concentrations in estuarine receiving waters. Our data showed a decline of atrazine concentrations in estuarine water in October and November which continued until a rainfall following Spring herbicide applications. Atrazine is enriched at the microsurface layer of estuarine water, but direct atmospheric input of atrazine did not seem to contribute significantly to the enrichment mechanism. Atrazine is believed to be transported long distances in polluted air masses. The estuarine microsurface layer could be a source of atmospheric atrazine, but the importance of the source is yet to be determined. Atrazine was quantitatively determined by GC using a nitrogen specific electrolytic detector and was confirmed by GC/Mass.
اظهر المزيد [+] اقل [-]Species and ecosystem level bioindicators of airborne pollution: an analysis of two major studies
1981
Grodzinski, W. (Jagiellonian Univ., Krakow (Poland). Dept. of Animal Ecology) | Yorks, T.P. (Colorado State Univ., Fort Collins, CO (USA). Natural Resource Ecology Lab.)
Bioindication of air pollution effects has received considerable attention in recent years. It has been almost entirely focused on individual species and relatively little notice has been given to ecosystem level process and function monitors. Longterm research projects in the Niepolomice Forest in southern Poland and the Colstrip area in southeast Montana, U.S.A., were analyzed for both organismic and system level indicators and monitors for SO, trace elements, and fluoride pollution originating in nearby coal-fired industrial processes. Species of lichens exhibited changes in morphology and survival and pine species exhibited pollutant accumulation in needles at both sites. Declines in Scots pine growth in Poland of up to 20% were compared with declines in western wheatgrass rhizome biomass in Montana to illustrate system wide effects on primary productivity. Directly observable declines in decomposition rate were noted for both sites at higher pollution levels and tied to system wide occurrences of nutrient deficiency and toxicant buildup in soil pools. Pollutant increases in deer antler composition, changes in grasshopper dietary patterns, and lichen density and health were postulated to have system level implications as well
اظهر المزيد [+] اقل [-]Element mass balances for South Carolina coastal plain watersheds [(USA)]
1981
Gardner, L.R. (South Carolina Univ., Columbia (USA). Dept. of Geology)
Element mass balance estimates for South Carolina Coastal Plain watersheds indicate that fertilizers and liming materials are the major sources for inputs of Ca, Mg, K, Cl, and HCO(,3) whereas precipitation is the major input for Na and SO(,4). Stream flow is the chief mode of output for all of these elements. A balance between input and output is evident only for Cl. Retentions of 50% or more are shown by Ca, Mg, K, HCO(,3), and SO(,4) whereas Na shows an apparent net loss. The retention of Ca, Mg and HCO(,3) suggests that less than 25% of the dolomitic liming materials applied to the landscape actually dissolve and that the carbonate chemistry of Lower Coastal Plain streams is therefore probably largely controlled by seepage of groundwaters from underlying calcareous aquifers. The retention of K and the loss of Na may be due to cation exchange reactions on soil clays whereas the apparent retention of SO(,4) is probably due to reduction to H(,2)S in floodplain environments and soil adsorption.
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