Supplemental oxygenation of electric generating station cooling water     

G. Fred Lee  George A. Frey 《Water, air, and soil pollution》1979,12(2):135-139

The Delaware River Basin Commission established the requirement that the Philadelphia Electric Eddystone Generating Station shall add 5000 pounds (≈2.3 tonnes) of dissolved oxygen (DO) per day to the Delaware River as a condition for increased use of cooling water at this station. It has been found that the Eddystone Station normally adds from ≈1 to 3 tonnes per day of DO to the river arising from entrainment of air into the cooling water discharge tunnel. Further additions can readily be accomplished by bleeding air into the condenser tailpipe. The Delaware River Basin Commission's requirements can readily be met without significant expenditure of funds and without altering normal plant operating conditions.  相似文献   

Determination of residues of nitromide in poultry tissues to concentrations of less than 0.010 parts per million     

Zietlow DC  Petzold EN  George GM  Morrison JL 《Journal of agricultural and food chemistry》1969,17(5):1059-1061

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With Darwin, earthworms turn intelligent and become human friends: The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002     

George G. Brown  Christian Feller  Eric Blanchart  Pierre Deleporte  Sergey S. Chernyanskii 《Pedobiologia》2003,47(5-6):924-933

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Nutrient and water uptake by roots of forest trees     

Eckhard George  Horst Marschner 《植物养料与土壤学杂志》1996,159(1):11-21

Although per growing season nutrient uptake of adequately growing forest trees is less than the nutrient uptake of annual crop species, nutrient uptake per unit root length in trees is considerable. Because of high heterogeneity of soil conditions and root growth in forest soils, modelling of uptake processes is even more difficult for forest than for crop stands. Detailed studies show that white lips of growing tree roots have a high nutrient uptake capacity. However, most root tips are usually colonised by mycorrhizal fungi. These fungi can participate substantially in tree nutrient uptake, in particular in the utilisation of organically-bound phosphorus and nitrogen in soils. Mycorrhizal hyphae, root tips, and older root zones can all absorb water, but their actual contribution is difficult to assess. In this review, experimental results from our laboratory and literature data are used to describe the potential activity of tree roots and mycorrhizas in nutrient and water uptake. Methodology for in situ measurements must be developed to quantify at different forest sites the actual contribution of mycorrhizas and different root parts.  相似文献   

FACE facility CO₂ concentration control and CO₂ use in 1990 and 1991     

John Nagy  Keith F. Lewin  George R. Hendrey  Elaine Hassinger  Robert LaMorte 《Agricultural and Forest Meteorology》1994,70(1-4)

CO₂ treatment level control and CO₂ use are reported for free-air carbon dioxide enrichment (FACE) facility operations at the University of Arizona's Maricopa Agricultural Center in 1990 and 1991. These are required for evaluation of the validity of biological experiments conducted in four replicates of paired experimental and control plots in a large cotton field and the cost-effectiveness of the plant fumigation facility. Gas concentration was controlled to 550 γmol mol^-1 at the center of each experimental plot, just above the canopy. In both years, season-long (April–September) average CO₂ levels during treatment hours (05:00–19:00 h Mountain Standard Time) were 550 γmol mol⁻¹ measured at treatment plot centers when the facility was operating. Including downtime, the season average was 548 γmol mol⁻¹ in 1991. In 1990, the season averages for the four elevated CO₂ treatments varied from 522 to 544 γmol mol⁻¹, owing to extended periods of downtime after lightning damage. Ambient CO₂ concentration during treatment was 370 γmol mol⁻¹. Instantaneous measurements of CO₂ concentration were within 10% of the target concentration of 550 γmol mol⁻¹ more than 65% of the time when the facility was operating, and 1 min averages were within 10% of the target concentration for 90% of the time. The long-term average of CO₂ concentration measured over the 20 m diameter experimental area of one array at the height of the canopy was in the range 550–580 γmol mol⁻¹ during July 1991, with the higher values near the edges. In 1991, CO₂ demand averaged 1250 kg per array per 14 h treatment day, or 4 kg m⁻² of fumigated plant canopy. The FACE facility provided good temporal and spatial control of CO₂ concentration and was a cost-effective method for large-scale field evaluations of the biological effects of CO₂.  相似文献   

Heavy Metals Contamination in Vegetables Grown in Urban and Metal Smelter Contaminated Sites in Australia   总被引：1，自引：0，他引：1  

Anthony George Kachenko  Balwant Singh 《Water, air, and soil pollution》2006,169(1-4):101-123

Dietary exposure to heavy metals, namely cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu), has been identified as a risk to human health through the consumption of vegetable crops. This study investigates the source and magnitude of heavy metal contamination in soil and vegetable samples at 46 sites across four vegetable growing regions in New South Wales, Australia. The four regions Boolaroo, Port Kembla, Cowra and the Sydney Basin were a mix of commercial and residential vegetable growing areas. The extent of metal contamination in soils sampled was greatest in regions located in the vicinity of smelters, such as in Boolaroo and Port Kembla. Soil metal concentrations decreased with depth at these two sites, suggesting contamination due to anthropogenic activities. Cadmium, Pb and Zn contamination was greatest in vegetables from Boolaroo, and Cu concentrations were greatest in vegetables sampled from Port Kembla. At Boolaroo, nearly all the samples exceeded the Australian Food Standards maximum level (ML) (0.01 mg kg^?1 fresh weight) of Cd and Pb in vegetables. Over 63% of samples exceeded international food standard guidelines set by the Commission of the European Communities and the Codex Alimentarius Commission. All vegetables sampled from Cowra, which is a relatively pristine site had Cd and Pb levels below the Australian and international food standards guideline values. This study suggests that the Australian guideline values are more conservative in defining the ML for Cd and Pb in vegetable crops. This investigation highlights the increased danger of growing vegetables in the vicinity of smelters.  相似文献   

Degradation of isoxaflutole (balance) herbicide by hypochlorite in tap water     

Lin CH  Lerch RN  Garrett HE  George MF 《Journal of agricultural and food chemistry》2003,51(27):8011-8014

Chlorine has been widely employed for the disinfection of drinking water. Additionally, it has the capacity to oxidize many organic compounds in water. Isoxaflutole (Balance; IXF) belongs to a new class of isoxazole herbicides. Isoxaflutole has a very short soil half-life and rapidly degrades to a stable and phytotoxic metabolite, diketonitrile (DKN). Further degradation of DKN produces a nonbiologically active benzoic acid (BA) metabolite. In experiments using high-performance liquid chromatography-UV spectroscopy (HPLC-UV) and HPLC tandem mass spectrometry (HPLC-MS/MS), DKN was found to rapidly react with hypochlorite in tap water, yielding the BA metabolite as the major end product. One milligram per liter (19 microM) of hypochlorite residue in tap water was able to completely oxidize up to 1600 microg/L (4.45 micromol/L) of DKN. In tap water, the disappearance of IXF was much more rapid than in DI water. As soon as the IXF is hydrolyzed to DKN, the DKN quickly reacts with the OCl(-) to form nonphytotoxic BA. As a result, the herbicide solutions prepared with tap water at 500 microg/L will no longer possess any herbicidal activity after 48 h of storage. However, in agronomic settings, highly concentrated tank solutions (600-800 mg/L) may be prepared with tap water since the conversion of IXF to BA would represent <5% of the herbicide; therefore, any impact on the herbicide efficacy would be negligible. Results of this study show that current chlorination disinfection protocols in municipal water systems would completely eliminate the phytotoxic form of this new herbicide, DKN, from drinking water supplies; yet, farmers can use chlorinated tap water without significant loss of efficacy.  相似文献   

Spectrophotometric methods to determine carbohydrates in soil   总被引：2，自引：0，他引：2  

Don A. Doutre  George W. Hay  Alan Hood  Gary W. Vanloon 《Soil biology & biochemistry》1978,10(6):457-462

Two common spectrophotometric procedures for determining neutral carbohydrates—the phenol-sulfuric acid and anthrone methods were evaluated for soil analysis. The phenol-sulfuric acid procedure gives results comparable to those obtained by gas-liquid chromatography, and is applicable to a variety of soil types. Prior removal of interfering substances by anion and cation exchange is required. Glucose is recommended as the spectrophotometric reference standard. The anthrone method is not satisfactory under the conditions employed.  相似文献   

Techniques for air pollution observation from space     

George Ohring  Joseph Otterman  Joachim Joseph 《Water, air, and soil pollution》1973,2(2):191-217

Air pollution problems of a scale larger than the point monitoring problem lend themselves to space observational techniques. Examples of these large scale problems are those associated with changes in the global background of gases and aerosols; potential stratospheric pollution resulting from SST operations; regional sources, pollution episodes, and large scale diffusion; and effects of pollutants on climate. These problems are discussed and observational requirements are specified. Possible remote sensing techniques for satellite monitoring are described. These include monitoring of pollutant gases and particulates by means of their absorption and scattering of radiation in both the solar spectrum range and terrestrial emission spectrum range. A discussion of potential difficulties includes the atmospheric and surface background problems, the temperature sensitivity problem in the terrestrial spectrum range, the band overlap problem, and the cloud interference problem. Recent observations from satellites and balloons are reviewed. It appears that except for H₂O, and, perhaps, O₃, measurements of the vertical profiles of atmospheric pollutant gases and aerosols from satellites will be extremely difficult. On the other hand, measurements of the total amounts (in a vertical column) of pollutant gases and aerosols do appear feasible.  相似文献   

Determination of isoxaflutole (balance) and its metabolites in water using solid phase extraction followed by high-performance liquid chromatography with ultraviolet or mass spectrometry   总被引：2，自引：0，他引：2  

Lin CH  Lerch RN  Thurman EM  Garrett HE  George MF 《Journal of agricultural and food chemistry》2002,50(21):5816-5824

Balance (isoxaflutole, IXF) belongs to a new family of herbicides referred to as isoxazoles. IXF has a very short soil half-life (<24 h), degrading to a biologically active diketonitrile (DKN) metabolite that is more polar and considerably more stable. Further degradation of the DKN metabolite produces a nonbiologically active benzoic acid (BA) metabolite. Analytical methods using solid phase extraction followed by high-performance liquid chromatography-UV (HPLC-UV) or high-performance liquid chromatography-mass spectrometry (HPLC-MS) were developed for the analysis of IXF and its metabolites in distilled deionized water and ground water samples. To successfully detect and quantify the BA metabolite by HPLC-UV from ground water samples, a sequential elution scheme was necessary. Using HPLC-UV, the mean recoveries from sequential elution of the parent and its two metabolites from fortified ground water samples ranged from 68.6 to 101.4%. For HPLC-MS, solid phase extraction of ground water samples was performed using a polystyrene divinylbenzene polymer resin. The mean HPLC-MS recoveries of the three compounds from ground water samples spiked at 0.05-2 microg/L ranged from 100.9 to 110.3%. The limits of quantitation for HPLC-UV are approximately 150 ng/L for IXF, 100 ng/L for DKN, and 250 ng/L for BA. The limit of quantitation by HPLC-MS is 50 ng/L for each compound. The methods developed in this work can be applied to determine the transport and fate of Balance in the environment.  相似文献