Energy Metabolism in Heart, Previous studies have demonstrated that acute or chronic exposureto ozone results in (1) alterations in the glutathione peroxidase system, and (2) the functional activity of sulfhydryls and sulfhydryl-contain+nq enzymes in lung tissue and erythrocytes. As a result, both structural damage and changes in metabolic profile occur. The present study examined tie effects of acute exposure to ozone on the metabolic properties of hamster heart(H), liver(L), and gastrocnemius(G) tissues. Measures included in vitro oxidative capacity(Q02) and the optimal activity of the marker enzymes 2-oxoglutarate Dehydrogenase(20GDII), Carnitine Palmitoyltransferase(CPT), hexokinase(HI;), Glucose-6-Phosphate Dehydrogenase(G6PDH), and Lactate Dehydrogenase(LDH). Relative to controls, both L and G tissues had significantlydepressed QC02 values(Pc0.01). Heart was unaffected. Significant treatment effects were also found for 20GDH(H,L), CPT(L), HK(H), and G6PDH(H). The data support previous work on lung and erythrocytes suggesting shifts in metabolic profiles in an attempt to counteract the deleterious effects of ozone exposure on cellular lipids or enzymes with sulfhydryl groups. Thepresent data also indicate that brief exposure to ozone will have an effect upon tissues other than the lungs or erythrocytes.

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No description available.

AbstractThe bactericidal effect of ozone at concentrations of 1 and 2 p.p.m. by volume, was tested on separately atmized resting cell suspensions of Aerobacter aerogenes, Bacillus megathreium, and Escherichia coli B impinged on Millipore filters. The exposure of each species required the use of 18 randomly selected filters containing impinged organisms. Of the 18 filters, 6 were used in the control. The temperature and the relative humidity of the ozone flow were approximately 25ºC and 20 per cent, respectively, while the flow-rate across each filter was 3 liters per minute. It was found that all of the organisms tested were completely destroyed by both 2 and 2 p.p.m. ozone within 2 minutes of exposure.Ball State UniversityMuncie, IN 47306

Ozone is recognized as one of the most dangerous irritants to eyes, throat, lungs and etc .. Chamber studies consistently have demonstrated adverse effects of ozone on human lung function. The results of epidemiological studies, however, have been controversial, partly because there are many factors that affect human lung function. Thus it has been difficult to control confounding in epidemiological studies. Among these factors, retention and ventilation are two of the more important because of their strong influence on ozone's physiologically effective dose. This study used a computer simulation model, utilizing data from the "children's Camp Study", to analyze the effects of retention factors and ventilation on ozone's physiologically effective dose. The results of the simulations indicated appreciable improvement in the estimated exposure to ozone when inhaled ozone exposure (effective dose) was included in the model. These results were consistent with the study's a priori- hypothesis (that incorporating retention and ventilation factors into the model would improve the estimated exposure to ozone) primarily because of the greater precision and reduction in bias associated with the use of heart rate data that were child-and hour-specific. The study identified three simulation data sets for which the ozone dose model yielded a more significant coefficient than did the average ozone concentration model. Using the t-statistic, the three models were seen to follow the expected pattern, with statistically significant differences between the R² values (the coefficient of variation changed from 45.4 to 11.0 when the error term was 0. 01). The results of the analyses support the hypothesis that ventilation and retention factors can be used to increase the precision of ozone exposure measurement and reduce exposure assessment errors significantly, thereby sharpening the power of studies evaluating ozone's acute health effects. / Graduation date: 1992

Water quality changes that occur during establishment and maintenance of nitrification in two identical recirculating aquaculture systems containing rainbow trout are described. The time taken for the nitrification process to become established was 40-45 days. Mortality of fish attributed to elevated nitrite concentrations were recorded during the initial conditioning phase of the systems. Un-ionised ammonia concentrations did not attain lethal levels during this period. Nitrate concentrations accumulated slowly throughout the study, while the pH and alkalinity of the water decreased with progressive nitrification. Levels of carbon dioxide, calcium, dissolved and suspended solids remained relatively stable until the carrying capacity of the systems was increased, upon which they increased rapidly and general water quality deteriorated. Permanently elevated concentrations of ammonia and nitrite served as an indication that the carrying capacity of the systems had been exceeded. The use of ozone as a water enhancement treatment in aquaculture systems during one- and six-hour applications was also considered in this study. Ozonation significantly reduced nitrite levels at · low concentrations (0,1 - 0,15 mg/l), although they returned to pre-treatment levels within a few hours of cessation of the treatment. The formation of an unstable, intermediate product that reforms as nitrite in the absence of ozone, rather than the complete oxidation of nitrite to nitrate, is proposed. Ozonation also resulted in decreased dissolved solids, and improved the clarity and odour of the water. Ozone had no effect on ammonia concentrations (at pH > 7,0), or on nitrate or calcium levels, and did not conclusively increase the redox potential of the water. Residual ozone concentrations up to 0,04 mg/l in a sixhour treatment had no harmful effects on rainbow trout, and there were no signs of gas-bubble disease arising from supersaturation of the water with oxygen. Activated carbon filters were effective at removing residual ozone from the water after treatment. Treatment of the water with oxygen alone had no effect on nitrite concentrations.

Radish plants (Raphanus sativus L. cv Cherry Belle) were exposed to 0.10 μl l⁻¹ ozone (O₃) or 0.50 μl l⁻¹ sulfur dioxide (SO2) for 4 h d⁻¹, 3 d wk⁻¹ for 3 weeks. From these fumigated plants, individuals were selected that were resistant or sensitive to these pollutants. The selected plants were used as parental material in a breeding program to produce lines differing in resistance to O₃ and SO₂. Non-selected (NS) plants from the original populations served as controls. F₁ populations were raised and exposed to O₃ or SO₂ with the same fumigation regime used for the parents. The plants were harvested 30 days after emergence and dry weights were determined. Plants selected for O₃ resistance (O3R) weighed significantly more than either plants selected for sensitivity to O₃ (O₃S) or NS plants when exposed to either O₃ or SO₂. The hypocotyl was most affected by pollutant exposure, leading to reduced root/shoot ratios. Plants selected for resistance or sensitivity to SO₂ generally had biomass production similar to that of NS plants. Growth analysis at early stages of growth indicated that both O₃R and O₃S plants had less growth under O₃ fumigated conditions; however, by maturity O₃R plants had similar amounts of growth under fumigated or non-fumigated conditions. Ozone fumigations tended to decrease free sugar concentrations in leaves at early stages of growth in both O₃R and O₃S plants, and caused some accumulations of carbohydrates during late stages of growth in O₃S plants. Allocation of Mc was significantly lower to hypocotyls and roots of O₃ fumigated O₃S plants. Allocation to hypocotyls of O₃R plants was not affected, although both O₃R and O₃S plant groups had lower photosynthetic rates due to O₃ fumigation. Ozone did not significantly affect chlorophyll concentrations in leaves of either sensitive or resistant plants, nor was the time of new leaf production affected by fumigation. These experiments demonstrated the potential of O₃ to influence the composition of sensitive plant populations. However, SO₂ was a much less powerful influence on the composition of these populations. / Ph. D.

The aim of this thesis is to examine the nature and characteristics of tropospheric ozone over Johannesburg, South Africa. Ozone, water vapour and meteorological profile data, which form part of the MOZAIC (Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft) database for the period 1995 to 2000 were utilized in this study. The thesis is divided into two main parts. The first part deals with the computation of total tropospheric ozone. A clear seasonal cycle, with ozone peaking in September and October is found. It is suggested that the main reason for the spring maximum is biomass burning, combined with prevailing anticyclonic circulation patterns, which facilitate the build-up of ozone over the region. Variability in TTO is greatest in January, September and November and least during autumn and winter (April to July). The lower day-to-day variability in autumn and winter is a reflection of the more settled weather at this time. Interannual variability is least in January and April to June. The autumn and winter ozone values are more consistent and appear to represent background tropospheric ozone loadings on which the dynamic and photochemical influences of other months are superimposed. High TTO events (>30 DU) occurred predominantly during September and October. Enhancements in the lower troposphere occurred mostly in September and seldom lasted for more than 1-2 consecutive days. It is suggested that these events are most likely due to effects of local surface pollution sources, either localised biomass burning or urban-industrial effects. An extended period of enhancement in the 7-12 km layer occurred from 14-17 September 1998 and again on 20 September 1998. The extended duration of this event suggests that it is due to an STE event. Confirmation of this was given in a case study of a particular MOZAIC flight on 16 September 1998 from Johannesburg to Cape Town. The second part of the thesis deals with the classification of ozone profiles and is used to find pattern and order within the profiles. TWINSPAN (Two-Way INdicator SPecies ANalysis), a cluster analysis technique, was used to classify the profiles according to the magnitude and altitude of ozone concentration. Six distinct groups of profiles have been identified and their characteristics described. The HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) trajectory model was used to relate the profiles to the origin of air masses, revealing clearly defined source regions. The mid-tropospheric peak in summer and the low to mid-tropospheric enhancement in spring is attributed to continental areas over central Africa and long-range transport while local sources are responsible for the winter low tropospheric enhancement. Reduced ozone values are due to westerlies bringing in clean maritime air. The classification has highlighted three important findings. Firstly, it has emphasized the pronounced seasonality of ozone profiles. It is evident that seasons are dominated by particular patterns and by inference, the processes and transport patterns that shape individual profiles are seasonally dependent. Secondly, the widely recognized spring maximum in tropospheric ozone has been confirmed in this classification, but a new and equally high summer mid-tropospheric enhancement due to the penetration of tropical air masses from continental regions in central Africa has been identified. Thirdly, it is suggested that the computation of a mean profile and furthermore, extrapolation of trends based on a mean profile is meaningless, particularly for a location on the boundaries of zonally defined meteorological regimes. / Thesis (M.A.)-University of Natal, Durban, 2002.