Carbon Monoxide in the Atmosphere

A carbon monoxide analyzer has been developed which is capable of continuous measurement of the carbon monoxide concentration in the atmosphere. The operating principle of the instrument is the reaction of carbon monoxide with hot mercuric oxide followed by the photometric determination of the mercury vapor produced. Oxygenated hydrocarbons and olefins are quantitatively detected. Those normally present are in the ambient atmosphere in low concentrations relative to CO. Hydrogen and methane in the atmosphere do not interfere with the CO analysis. Measurements of atmospheric CO concentrations in California, Greenland, and Oregon seem to indicate that CO content is an air mass characteristic. North Pacific marine air mass concentrations may be as low as about 0.040 parts per million (ppm) CO, while the air mass over continental California seems to be characterized by CO levels of 0.5-1.0 ppm or greater.     

Atmospheric versus biological sources of polycyclic aromatic hydrocarbons (PAHs) in a tropical rain forest environment

To distinguish between pyrogenic and biological sources of PAHs in a tropical rain forest near Manaus, Brazil, we determined the concentrations of 21 PAHs in leaves, bark, twigs, and stem wood of forest trees, dead wood, mineral topsoil, litter layer, air, and Nasutitermes termite nest compartments. Naphthalene (NAPH) was the most abundant PAH with concentrations of 35 ng m(-3) in air (>85% of the sum of 21PAHs concentration), up to 1000 microg kg(-1) in plants (>90%), 477 microg kg(-1) in litter (>90%), 32 microg kg(-1) in topsoil (>90%), and 160 microg kg(-1) (>55%) in termite nests. In plants, the concentrations of PAHs in general decreased in the order leaves > bark > twigs > stem wood. The concentrations of most low-molecular weight PAHs in leaves and bark were near equilibrium with air, but those of NAPH were up to 50 times higher. Thus, the atmosphere seemed to be the major source of all PAHs in plants except for NAPH. Additionally, phenanthrene (PHEN) had elevated concentrations in bark and twigs of Vismia cayennensis trees (12-60 microg kg(-1)), which might have produced PHEN. In the mineral soil, perylene (PERY) was more abundant than in the litter layer, probably because of in situ biological production. Nasutitermes nests had the highest concentrations of most PAHs in exterior compartments (on average 8 and 15 microg kg(-1) compared to <3 microg kg(-1) in interior parts) and high PERY concentrations in all compartments (12-86 microg kg(-1)), indicating an in situ production of PERY in the nests. Our results demonstrate that the deposition of pyrolytic PAHs from the atmosphere controls the concentrations of most PAHs. However, the occurrence of NAPH, PHEN, and PERY in plants, termite nests, and soils at elevated concentrations supports the assumption of their biological origin.     

Avoidance of toxic mixing zones by Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.) in the limed River Audna, southern Norway

Chlorophyll a (chl a) fluorescence was used to determine the effects of treatments with gaseous HF or aqueous solutions of NaF on the photosynthetic apparatus of spinach prior to the appearance of visible injury. Placing the petioles in 2 mM NaF for 3 h resulted in the accumulation of 240 ppm F in leaf blades. The second oldest leaves of spinach plants accumulated similar concentrations (270 ppm F) when the plants were exposed to gaseous HF at 5 microg F m(-3) for 6 days. These NaF and HF treatments did not result in visible injury nor did they affect Fo, Fm or Fv/Fm. However, during the slow (>2 s) induction kinetics, fluorescence quenching in fluoride-treated leaves increased during the P to S phase and the M peak was no longer resolved. This was due, in part, to increased photochemical quenching. The results are consistent with a reduced ability to develop or maintain a trans-thylakoid proton gradient in chloroplasts containing elevated concentrations of F.     

Influence of a diet of fluoride-fed cockerels on reproductive performance of captive American kestrels

In 1982, twenty-four pairs of captive American kestrels (Falco sparverius) were forced to renest by removal of their first clutches 6 days after their completion. Immediately following, each of three groups of eight pairs was randomly assigned to one of three daily dietary regimes for 10 days: (1) three 1-day old cockerels with background levels of F(-) (62.4+/-51ppm, mean+/-SD) in their femurae, (2) two 10-day old cockerels with 4512+/-810ppm of F(-) in their femurae, (3) two 10-day old cockerels with 7690+/-417ppm of F(-) in their femurae. Fluoride levels in femurae of treated kestrels were significantly (P<0.0025) higher than those of control birds. Clutch sizes tended to be smaller as more fluoride was added to the diet, but not significantly so, due to an increase of the variance in the treatment group. Per cent fertility and per cent hatchability were not significantly affected by treatment. The fluoride content in eggshells in the fluoride-treated groups differed significantly from those of the control group (P<0.001).     

Reduction of net photosynthesis in oats after treatment with low concentrations of ozone

Oats (Avena sativa L. cv Titus) were exposed to low concentrations of O3 in an assimilation chamber system. Net photosynthesis (net CO2 uptake), measured before and after O3 fumigation, showed significantly different responses for leaves of different age. The oldest active leaf was the most sensitive to O3. Net photosynthesis was depressed after 2 h with 0.075 ppm (150 microg m(-3)) O3. For leaves exposed to 0.150 ppm (300 microg m(-3)) O3 for 2 h, net photosynthesis was reduced significantly for 4 h, after which recovery occurred, nearly reaching the preexposure level 19 h after the exposure. Dark respiration was initially more than doubled after exposure to 0.130 ppm (260 microg m(-3)) O3. There was no visible injury after any of the experiments. The results indicate that O3 may cause crop losses through effects on photosynthesis even in Scandinavia, where a typical O3 episode lasts 1 to 2 h, and the concentration seldom exceeds 0.150 ppm.     

春蚕期桑叶氟化物含量变化规律分析与研究

春蚕桑叶氟化物中毒引起政府部门的高度重视。通过对历年来桑叶含氟量监测数据统计分析，找出春蚕期桑叶含氟量日均值变化规律，并对规律成因进行探讨研究，为春蚕防氟工作提供科学依据。     

Relative sensitivity of greenhouse pot plants to long-term exposures of NO- and NO2-containing air

Thirty-five cultivars of pot plants of 20 families were exposed for 50-64 days in a greenhouse facility to either 1 microl litre(-1) NO with 0.5 microl litre(-1) NO2, or 1 microl litre(-1) NO2 with 0.1 microl litre(-1) NO for 15 h each day, with air which was free from these gases as the reference. A sensitivity ranking of the pot plants was compiled, with the highest priority on visible injuries, followed by growth reductions, primarily as a response to the NO-dominated exposures, simulating the NOx-polluted environment in direct-fired, CO2-enriched greenhouses. This treatment reduced the leaf dry weight more than the number and area of the leaves. Twenty-two cultivars were significantly injured, while two (Hibicus sp, Epipremnum pinnatum, green) were significantly improved. The NOx-sensitivity of pot plants was highest in cultivars with variegated, small or narrow leaves, and in the Moraceae family. Nine cultivars (Ficus elastica 'Robusta', F. benjamina, F. pumila 'Sonny', Dieffenbachia maculata 'Camilla', F. elastica 'Tineke', Epipremnum pinnatum 'Marble Queen', Begonia elatior 'Nelson', Cyclamen persica, Poinsettia 'Mini') were specifically sensitive to the NO-containing exposure; six were specifically sensitive to the NO2-containing exposure (F. elastica 'Robusta', Asparagus den. 'Sprengeri', Hedera helix 'Shamrock', Aspledium nidus, Aster novo-belgii, Hypoestes phyl. 'Betina'); and 12 (Soleirolia soleirolii, Asparagus den. 'Sprengeri', H. helix 'Ester', Codiaeum 'Pictum', Rosa 'Minimo Red', F. benjamina 'Starlight', Saintpaulia ionantha 'light blue', F. pumila, Rhododendron simsii, H. helix 'Shamrock', Hibiscus sp., E. pinnatum) were equally sensitive to mixtures dominated by either gas, as measured by at least one response parameter.     

A congener-specific PCDD/F emissions inventory for the UK: do current estimates account for the measured atmospheric burden?

Considerable effort has been expended in the UK and elsewhere to quantify and rank PCDD/F primary sources and emissions to the environment, principally the atmosphere, so that cost-effective source reduction measures can be taken. Here, we predict a congener-specific emissions inventory for primary and secondary nondioxin-regulated sources to the UK atmosphere, estimated to have ranged from 3 to 22 kg in 1996. The inventory profile is dominated by OCDD (approximately 30-40%), 1,2,3,4,6,7,8-HpCDD (approximately 15-19%) and 1,2,3,4,6,7,8-HpCDF (approximately 14-19%). Congeners 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD dominate the sigmaTEQ composition. Mass balance modelling suggests that the predicted congener pattern in UK air (based on the emission inventory) is similar to observed measurements, with absolute concentrations being estimated within a factor of 2 for most congeners. Calculations taking into account atmospheric weathering processes and long range (advective) transport suggest that PCDD/F sources to ambient air are primarily ongoing and that atmospheric mixing will mask individual emission source profiles/identities. This supports measured evidence for the consistency of PCDD/F air profiles observed around the UK throughout the year.     

Detection and Measurement of Air Pollutants by Absorptions of Infrared Radiation

A technique of detecting gaseous air pollutants by means of absorption of laser radiation is under development at the NASA Electronics Research Center. The iodine infrared laser and the carbon dioxide infrared laser are forced to emit spectral lines which fall on the infrared absorption bands of atmospheric pollutants. The attenuation of a laser line when passed through an air sample is the measure of the pollutant concentration. The narrow spectral width of the laser emission permits sensitive detection, minimizes interference between pollutants, and allows penetration of atmospheric water bands. The collimation and high power outputs available from lasers permit transmission of the radiation over long straight paths through the atmosphere and over long folded paths in multiple-pass absorption cells. A sample of absorbing gas placed within the laser cavity forces the emission of the selected wavelengths. With a one-half kilometer path to a retro-reflector and back, it is predicted that the following concentrations of air pollutants will be detected by means of the indicated laser lines: carbon monoxide at 2 parts per million in air (ppm), using the 4.86 micron iodine line; nitric oxide at 1 ppm, using the 5.5 micron iodine line; ethylene at 0.1 ppm, using the 10.53 micron carbon dioxide line; sulfur dioxide at 1.5 ppm, using the 9.08 micron carbon dioxide line; and ozone at 0.15 ppm, using the 9.52 micron carbon dioxide line. It seems feasible to extend the technique to other gaseous pollutants such as nitrogen dioxide, methane, butane, and peroxy acetyl nitrate. Continuing effort is being devoted to development and construction of the laser transmitting and receiving equipment. Field testing is planned for the near future.     

Trends of PCDD/F and PCB concentrations and depositions in ambient air in Northwestern Germany

Time series of polychlorinated dioxins and furans (PCDD/F) and polychlorinated biphenyls (PCB) in ambient air of a large conurbation in North-Western Germany are presented and analyzed. The trend of PCDD/F concentrations, starting from as early as 1988, shows a pronounced decrease by at least one order of magnitude, demonstrating that the emission reductions were effective. The PCDD/F depositions also have decreased by a factor of 5 since 1992. However, both trends have leveled out since 2005. Time series of PCB concentrations and depositions starting in 1994 show only slight decreases for the concentrations and almost no decrease for the depositions. From the decay rates following first order kinetics, half-lives in the order of 5-15 years for the PCDD/F and 15-31 years for the sum of the six indicator PCB could be calculated, which are much longer than the half-lives estimated from their reactivity towards the OH radical. Apparently, small fresh emissions (PCDD/F), considerable secondary emissions and evaporation from contaminated soils slow down their decay in the atmosphere of big conurbations. Analyzing the decay rates of individual PCB congeners shows that the lower chlorinated and more volatile ones are removed faster than the higher chlorinated congeners, probably via gas phase reactions with the OH radical. It can be concluded from the present study that the input of PCDD/F and PCB into the food chain via the air path will continue for another one or two decades in big conurbations.     

The influence of ozone exposure dynamics on the growth and yield of kidney bean

A field experiment was conducted in open-top chambers to assess the importance of peak exposure concentration and exposure frequency on the responses of kidney bean plants to O3. There were five treatments in the study: charcoal-filtered air, constant exposure to 0.05 ppm O3 (131 microg m(-3)) daily. fluctuating exposure to 0.08 ppm O3 on three alternate days, cluster exposure to 0.08 ppm O3 on three consecutive days, and peak exposure to 0.12 ppm O3 on two consecutive days. Exposures lasted 4 h and produced an average weekly exposure-period concentration of approximately 0.05 ppm in the O3-addition treatments and 0.025 ppm in the charcoal-filtered treatment. Exposures began on June 23 and terminated on September 8. Plants were harvested weekly and assessed for the number, area, and dry mass of leaves; dry mass of stems; dry mass of roots; the number of pods; and the incidence of foliar O3 injury. Yield was assessed at the end of the study. There were no consistent differences between the plants receiving charcoal-filtered air and those receiving O3 exposure. Significant differences were detected among the treatments for several of the growth variables assessed at the interim harvests, but in the final two harvests these differences had mostly disappeared. There were no significant effects of the O3-addition treatments on yield when compared to the plants receiving charcoal-filtered air. This indicates that there were no cumulative impacts on plants exposed to 0.12 ppm O3 for 4 h on two consecutive days followed by filtered air compared to plants receiving charcoal-filtered air. The seasonal 7-h average concentrations of O3 in the peak and filtered air treatments were approximately 0.040 and 0.025 ppm, respectively.     

Ambient Carbon Monoxide And Its Fate in the Atmosphere

Carbon monoxide, the most abundant air pollutant found in the atmosphere generally exceeds that of all other pollutants combined (excluding C0₂). An estimated tonnage of >87 X 10⁶ of CO was emitted in the United States from major technological sources alone during 1966. More than 90% of the total CO emitted from fossil fuels is derived from gasoline powered motor vehicles. Other sources of CO include emissions from coal and fuel oil burning, aircraft and open burning. Some CO is also formed by certain vegetation and marine invertebrates (siphonophores). Chemical reactions of CO in the upper and lower atmosphere are discussed. Chemical oxidation of CO in the lower atmosphere by molecular oxygen is very slow. The exact duration of CO in the lower atmosphere is not known with certainty; however, the mean residence time has been variously estimated to be between 0.3 and 5.0 years. In the absence of scavenging processes the estimated world-wide CO emission would be sufficient to raise the’atmospheric level by 0.03 ppm per year, yet the background levels of CO in clean air do not appear to be increasing. Several potential sinks are discussed. Knowledge of the mechanism of process of removal of CO from the lower atmosphere is unsatisfactory; the process, at the present time, cannot be identified with certainty.     

Evaluation of mercury contamination using plant leaves and humus as indicators

Plant leaves and humus were collected from three areas with and without mercury emission sources. Mercury in these samples were determined by cold flameless atomic absorption spectrometry. A part of mercury emitted from the source into the atmosphere is absorbed by plant leaves, and move to humus through fallen leaves. Consequentry, plant leaves are able to be used as an indicator for the evaluation of mercury in air at present. Humus is usefull for the evaluation of mercury contamination through the air from the past to present.     

Effects of fluorine emission on agricultural products surrounding an aluminum factory

The F concentrations of precipitate dust, agricultural products, and fingernail and hair at the surrounding Al factory were investigated. The F content of dust ranged from 15400 to 42500 micrograms/g dry weight, 190,000 to 380,000 micrograms/g Al. Rice grain contained about 3.4 times more F than that in the control area, but some kinds of agricultural products, egg plants (S. melongena L.), mulberry plants (M. japonica Bailey non Sieb.), and soy beans (G. max (L.) Merrill) were almost equal to that of controls. Also, the high F concentration in the hair and nails of some workers was affected by available F contents in the emission from the factory as well as food and water surrounding the aluminum factory compared with those of control area.     

Ozone stress and antioxidant substances in Trifolium repens and Centaurea jacea leaves

Ozone-sensitive (NC-S clone) and resistant plants (NC-R clone) of Trifolium repens and Centaurea jacea were exposed to moderate ozone concentrations in ambient air. The aim of this study was the investigation of the relation between ozone-sensitivity and leaf concentrations of antioxidants (ascorbic acid, total phenolics and total antioxidant capacity). NC-R clone showed the highest concentrations of antioxidants with 50-70% more ascorbic acid than NC-S. NC-R had about 5 times more ascorbic acid in the young leaves and 9 times more in the old leaves than Centaurea. In a fumigation experiment with acute ozone stress (100 nl L(-1)) the antioxidant levels changed profoundly. The ozone-injured leaves of NC-S had 6-8 times more total phenolics than uninjured leaves. Generally older leaves had lower antioxidant concentrations and were more prone to ozone injury than younger leaves. Ascorbic acid concentrations were closer related to the appearance of visible ozone injury than the other antioxidative parameters.     

Screening loblolly pine seedling responses to SO2 and O3: analysis of families differing in resistance to fusiform rust disease

Open pollinated families of loblolly pine differing in resistance to fusiform rust disease were screened in laboratory studies for responses to gaseous air pollutants. Twenty families were given acute exposures (2 fumigations for 4 h each) to SO(2) (0.4-1.0 ppm), O(3) (0.25 ppm), SO(2) (0.4-1.0 ppm) + O(3) (0.25 ppm) and control. Analyses of variance were performed to evaluate the treatment effects of these air pollutants on percent foliar injury, and to determine whether the families responded differentially to the air pollution treatments. Treatment effects were significant, with the combination treatment of SO(2) + O(3) producing a higher percentage of foliar injury than the controls; however, injury levels were very low and may not be of biological significance. Subsequently, twelve families were grown in two soil types for exposure to chronic levels of SO(2) (0.06 ppm), O(3) (0.07 ppm), SO(2) (0.06 ppm) + O(3) (0.07 ppm) and control. The families were then ranked for decreased primary shoot growth, shoot dry weight, root dry weight, total plant dry weight and root/shoot ratio after exposure to air pollution treatments. Air pollution treatments as a main effect were significant for only one of five growth parameters measured, that of primary shoot growth. The main effect of family, and the interaction of family and air pollution treatments, were significant for most growth parameters measured. In general, O(3) alone and in combination with SO(2) reduced growth more than SO(2) alone. Fumigation with O(3) reduced growth of two families in comparison with control groups, whereas SO(2) alone produced decreased growth in one family and stimulated growth in three families. Treatment with O(3) alone produced higher root/shoot ratios than fumigation with charcoal-filtered air in two families. Overall, families which were fast growers under control conditions maintained their ranking after exposure to air pollution. Families producing less growth in charcoal-filtered air also produced less growth under various air pollution regimes. Results indicated that these families exhibited a high degree of resistance to air pollution injury. Growth responses of seedlings may not reflect family differences in long-term productivity. No relationship was apparent between fusiform rust resistance and growth reductions due to air pollutants.     

The linear accumulation of atmospheric mercury by vegetable and grass leaves: Potential biomonitors for atmospheric mercury pollution

One question in the use of plants as biomonitors for atmospheric mercury (Hg) is to confirm the linear relationships of Hg concentrations between air and leaves. To explore the origin of Hg in the vegetable and grass leaves, open top chambers (OTCs) experiment was conducted to study the relationships of Hg concentrations between air and leaves of lettuce (Lactuca sativa L.), radish (Raphanus sativus L.), alfalfa (Medicago sativa L.) and ryegrass (Lolium perenne L.). The influence of Hg in soil on Hg accumulation in leaves was studied simultaneously by soil Hg-enriched experiment. Hg concentrations in grass and vegetable leaves and roots were measured in both experiments. Results from OTCs experiment showed that Hg concentrations in leaves of the four species were significantly positively correlated with those in air during the growth time (p?<?0.05), while results from soil Hg-enriched experiment indicated that soil-borne Hg had significant influence on Hg accumulation in the roots of each plant (p?<?0.05), and some influence on vegetable leaves (p?<?0.05), but no significant influence on Hg accumulation in grass leaves (p?>?0.05). Thus, Hg in grass leaves is mainly originated from the atmosphere, and grass leaves are more suitable as potential biomonitors for atmospheric Hg pollution. The effect detection limits (EDLs) for the leaves of alfalfa and ryegrass were 15.1 and 22.2 ng g^–1, respectively, and the biological detection limit (BDL) for alfalfa and ryegrass was 3.4 ng m^–3.     

Lead induced changes in antioxidant metabolism of horsegram (Macrotyloma uniflorum (Lam.) Verdc.) and bengalgram (Cicer arietinum L.)

One-month old horsegram (Macrotyloma uniflorum (Lam.) Verdc. cv VZM1) and bengalgram (Cicer arietinum L. cv Annogiri) were exposed to different regimes of lead stress as Pb(NO3)2 at 0, 200, 500 and 800 ppm concentrations. The extent of oxidative damage as the rate of lipid peroxidation, antioxidative response and the accumulation of lead in roots and shoots of both plants were evaluated after 12 days of lead stress. Lead (Pb) treated plants showed increased levels of lipid peroxidation as evidenced from the increased malondialdehyde content coupled with the increase in the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione reductase (GR), glutathione S-transferase (GST) compared to control (untreated) plants. Lead stress caused significant changes in the activity of antioxidative enzymes. The effect of lead was found to be concentration dependent. Higher concentration of lead (800 ppm) resulted 2- to 3-fold increase in SOD, catalase and peroxidase activities, 3- to 5-fold increase in GR activity and 3- to 4-fold increase in GST activity in roots and leaves of both horsegram and bengalgram plants. Lead stress caused a significant increase in the rate of peroxidation as showed in the levels of malondialdehyde content in roots and leaves of both plant species. Horsegram registered lower Pb accumulation than bengalgram, however localization of Pb was greater in roots than leaves in both plants. In general, lipid peroxide levels and antioxidative enzyme activities were higher in horsegram than bengalgram and also more in roots than leaves which best concordance with the lead contents of both the plants and organs. These results suggest that Pb toxicity causes oxidative stress in plants and the antioxidative enzymes SOD, CAT, POD, GR, GST could play a pivotal role against oxidative injury.     

桑叶表面氟化物吸附积累规律的统计研究

以各气象因素和大气氟化物浓度为生态因子,对大田桑园中各叶位桑叶的氟化物的吸附积累规律,进行了统计分析和研究,建立了各叶位桑叶的氟化物的吸附积累模型。     

Tolerance to trichlorophenols in microorganisms from a polluted and a pristine site of a river

The effect of 2,4,5- and 2,4,6-trichlorophenol on the microbiota from a polluted and a pristine site of a river was studied. Bacterial metabolic activity measurements by epifluorescence microscopy showed that the polluted site contained more metabolically active cells than the pristine site. Total culturable bacterial counts and tolerant bacterial counts from both sites were not affected by incubation (for up to 5 days) with 200 ppm of chlorophenols. However, the incubation with 500 ppm of 2,4,5-trichlorophenol prevented detection of total and tolerant bacterial counts in the pristine site, and inhibited tolerants in the polluted site. None of 250 bacterial colonies directly isolated from these samples was able to grow on chlorophenols. However, bacteria able to grow on 2,4,6-trichlorophenol, were obtained by enrichment of water and sediments samples.