Уточнить поиск
Результаты 111-120 из 304
Sulphur and nitrogen nutrition and misting effects on the response of bluegrass to ozone, sulphur dioxide, nitrogen dioxide or their mixture
1981
Elkiey, T. | Ormrod, D.P. (Guelph Univ., Ontario (Canada). Dept. of Horticultural Science)
Kentucky bluegrass (Poa pratensis L.) plants, cultivars Cheri, Merion and Touchdown were grown at complete nutrition or with low S or low N. Plants were exposed to 10 ppm (v/v) O(,3) for 6 h/d, 15 pphm SO(,2) continuously, 15 pphm NO(,2) continuously, or their mixture at these concentrations for 10 days. The severity of injury was much increased by misting with deionized water for 5 min twice daily, especially with SO(,2) and NO(,2) single gas exposures. The misting did not have consistent effects on total S, total N, leaf area or fresh weight. Exposure to O (,3) decreased leaf area without affecting S or N content, while SO(,2) usually increased total S and, in some cases, increased total N. Exposure to NO(,2) increased total N without affecting total S, and the mixture increased both total S and total N. Low S or low N usually enhanced the effect of SO(,2) or NO(,2), respectively. Leaf area and fresh weight were not as responsive to the treatments as total S and total N. Rainfall outdoors may be a major meteorological factor affecting plant injury response to gaseous pollutants
Показать больше [+] Меньше [-]Occurrence and distribution of chemical pollutants in Lake Mariut, Egypt, 2: heavy metals, [(Tilapia fish)]
1981
Saad, M.A.H. | Ezzat, A.A. | El-Rayis, O.A. | Hafez, H. (Alexandria Univ. (Egypt). Faculty of Science, Oceanography Dept.)
The occurrence and distribution of heavy metals in the water of Lake Mariut, a heavily polluted brackish water lake in Egypt, and their accumulation in the different parts of Tilapia fish in this lake were studied. The variations in concentrations of the metals (Zn, Cu, Fe, Mn and Cd) in the lake water are mostly due to variations in the discharge rate of dumped wastes. The mean concentrations of these metals in different fish parts were much higher than those in the lake water.
Показать больше [+] Меньше [-]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.
Показать больше [+] Меньше [-]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.
Показать больше [+] Меньше [-]Element mass balances for South Carolina coastal plain watersheds [USA]
1981
Gardner, L.R. (South Carolina Univ., Columbia (USA). Dept. of Geology)
Aquatic pollution
1981
Laws, Edward A.
New York : Wiley, 1981.
Показать больше [+] Меньше [-]Environmental factors influencing the rate of spread of the grass Deschampsia cespitosa invading areas around the Sudbury [Canada] nickel-copper smelters
1981
Cox, R.M. | Hutchinson, T.C. (Toronto Univ., Ont. (Canada). Dept. of Botany and Inst. for Environmental Studies)
A study has been made of the soil chemistry and atmospheric quality of 9 Sudbury area sites where populations of Deschampsia cespitosa have invaded the contaminated industrial barrens near the smelters since 1972. The rate of increase in cover within marked quadrats was greater at sites near the disused Coniston smelter than at sites near the two active smelters. Air quality monitoring, using bulk collectors and sulphation plates, indicated substantial drops in phytotoxic air pollutants during the 1978-79 smelter shutdowns. Surface loadings of various metals were evident in soil at sites near the active smelters, whereas this was no longer true at sites near the Coniston smelter disused since 1972. However, water extractable levels of Ni and Cu at these sites remained as high as those found near the active smelters which also have high extractable soil Al. Both comparative studies and multiple regression analysis indicate that the rate of increase in cover of D. cespitosa in the populations studied correlate best with particulate deposition of Cu and Ni followed by sulphation rate and then by soil extractable Al. These findings are discussed in relation to tolerances of local populations, as well as to the potential effects of airborne particulates on growth
Показать больше [+] Меньше [-]Trace element concentrations in tropical marine fish at Bougainville Island, Papua New Guinea
1981
Powell, J.H. (Bougainville Copper Limited, Panguna, Bougainville Island (Papua New Guinea). Environment Dept.) | Powell, R.E. | Fielder, D.R.
Baseline trace element concentrations have been measured in 8 species of marine fish from Bougainville Island, Papua New Guinea. This is the first stage in an assessment of environmental impact associated with mining operations. In general, concentrations of Cu, Pb, Zn, Cd, Hg, and As in edible portions of the fish comply with Australian National Health and Medical Research Council public health standards. Two species of shark contained As concentrations in muscle tissue in excess of prescribed standards. Increased concentrations of Cu, Zn and Cd were recorded in liver and kidney, But Hg and Pb were not preferentially accumulated in these organs. The relationship between the size of fish and metal assay was investigated. Mercury content and weight of fish were always positively correlated but concentrations of other metals were variably correlated with size
Показать больше [+] Меньше [-]The role of atmospheric deposition in an eastern U.S. deciduous forest
1981
Lindberg, S.E. (Oak Ridge National Lab., Oak Ridge, TN (USA). Environmental Sciences Div.) | Hariss, R.C.
Atmospheric sources contributed significantly to the annual flux of trace metals and sulfate to the forest floor of Walker Branch Watershed, a forested catchment in the southeastern United States. Atmospheric deposition supplied from 14%(Mn) to approx. 40%(Zn, Cd, SO(,4)('2-)) to 99%(Pb) of the annual flux to the forest floor; the remainder was attributable to internal element cycling. The measured water solubility of these metals in suspended and deposited particles indicates that they may be readily mobilized following deposition. Dry deposition constituted a major fraction of the total annual atmospheric input of Cd and Zn(20%), SO(,4)('2-)(35%), Pb(55%), and Mn(90%); however, wet deposition rates for single events exceeded dry deposition rates by one to four orders of magnitude. Interception of rain by the canopy resulted in loss of Cd, Mn, Pb, Zn, and SO(,4)('2-) from the canopy, but uptake of H('+) which increased with increasing free acidity of the incoming rain, and with increasing residence time of the rain on the leaf surface
Показать больше [+] Меньше [-]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.)