Effect of Nitrogen Nutrition on the Response of Tobacco to Ozone in the Atmosphere

Experiments were conducted to determine the effect of nitrogen nutrition on the response of tobacco to ozone in the atmosphere. With Nicotiana rustica L., a noncommercial tobacco, plants receiving an “optimum” nitrogen supply were found to be more susceptible to ozone injury than those receiving deficient or luxury supplies. Furthermore, it was found on analyses of the third oldest tobacco leaf that, while these “optimum” plants showed little or no increase in respiration as a result of ozone in concentrations too low to produce visible injury, plants grown with deficient or excess nitrogen showed a significant increase in respiration under these same conditions. The increase in respiration was accompanied by a comparable and equally significant decrease in carbohydrate con-lent in the latter plants which was not apparent in plants at the “optimum” nitrogen supply, as well as an increase in total nitrogen, protein-nitrogen, and amino-acid nitrogen. In conclusion, it is suggested that the carbohydrate reserve built up in plants grown with deficient nitrogen nutrition serves as protection against the ozidative potential of ozone. Likewise, a decrease in carbohydrate content below that of “optimum” plants provides protection in plants grown with an overabundance of nitrogen fertilization, though possibly by a more complex mechanism.     

Uncertainty Analysis of Ozone Formation and Response to Emission Controls Using Higher-Order Sensitivities

Abstract

Understanding ozone response to its precursor emissions is crucial for effective air quality management practices. This nonlinear response is usually simulated using chemical transport models, and the modeling results are affected by uncertainties in emissions inputs. In this study, a high ozone episode in the southeastern United States is simulated using the Community Multiscale Air Quality (CMAQ) model. Uncertainties in ozone formation and response to emissions controls due to uncertainties in emission rates are quantified using the Monte Carlo method. Instead of propagating emissions uncertainties through the original CMAQ, a reduced form of CMAQ is formulated using directly calculated first- and second-order sensitivities that capture the nonlinear ozone concentration-emission responses. This modification greatly reduces the associated computational cost. Quantified uncertainties in modeled ozone concentrations and responses to various emissions controls are much less than the uncertainties in emissions inputs. Average uncertainties in modeled ozone concentrations for the Atlanta area are less than 10% (as measured by the inferred coefficient of variance [ICOV]) even when emissions uncertainties are assumed to vary between a factor of 1.5 and 2. Uncertainties in the ozone responses generally decrease with increased emission controls. Average uncertainties (ICOV) in emission-normalized ozone responses range from 4 to 22%, with the smaller being associated with controlling of the relatively certain point nitrogen oxide (NO_x) emissions and the larger resulting from controlling of the less certain mobile NO_x emissions. These small uncertainties provide confidence in the model applications, such as in performance evaluation, attainment demonstration, and control strategy development.     

Response of Bean and Tobacco to Ozone: Effect of Light Intensity,Temperature and Relative Humidity

Pinto bean (Phaseolus vulgaris, L.) and Bel W₃ tobacco (Nicotiana tabacum, L.) were grown and exposed to 40 pphm ozone for 1 hr under a range of light intensities, temperatures, and relative humidities. Foliar injury to the more sensitive plant leaves was determined on the third day after exposure. Each atmospheric factor was independently assessed. Two significant three-way interactions were found: exposure light intensity by growth light intensity by species, and growth temperature by exposure temperature by species. Three significant two-way interactions were found for humidity: growth humidity by exposure humidity, growth humidity by species, and exposure humidity by species. The sensitivity of each species to ozone changed with changes in each environmental condition.     

Ozone disintegration of excess biomass and application to nitrogen removal.

A pilot-scale facility integrated with an ozonation unit was built to investigate the feasibility of using ozone-disintegration byproducts of wasted biomass as a carbon source for denitrification. Ozonation of biomass resulted in mass reduction by mineralization as well as by ozone-disintegrated biosolids recycling. Approximately 50% of wasted solids were recovered as available organic matter (ozonolysate), which included nonsettleable microparticles and soluble fractions. Microparticles were observed in abundance at relatively low levels of ozone doses, while soluble fractions became dominant at higher levels of ozone doses in ozone-disintegrated organics. Batch denitrification experiments showed that the ozonolysate could be used as a carbon source with a maximum denitrification rate of 3.66 mg nitrogen (N)/g volatile suspended solids (VSS) x h. Ozonolysate was also proven to enhance total nitrogen removal efficiency in the pilot-scale treatment facility. An optimal chemical oxygen demand (COD)-to-nitrogen ratio for complete denitrification was estimated as 5.13 g COD/g N. The nitrogen-removal performance of the modified intermittently decanted extended aeration process dependent on an external carbon supply could be described as a function of solids retention time.     

Exposure of Chronic Obstructive Pulmonary Disease Patients to Particulate Matter: Relationships between Personal and Ambient Air Concentrations

ABSTRACT

Most time-series studies of particulate air pollution and acute health outcomes assess exposure of the study population using fixed-site outdoor measurements. To address the issue of exposure misclassification, we evaluate the relationship between ambient particle concentrations and personal exposures of a population expected to be at risk of particle health effects.

Sampling was conducted within the Vancouver metropolitan area during April-September 1998. Sixteen subjects (non-smoking, ages 54-86) with physician-diagnosed chronic obstructive pulmonary disease (COPD) wore personal PM_{2 5} monitors for seven 24-hr periods, randomly spaced approximately 1.5 weeks apart. Time-activity logs and dwelling characteristics data were also obtained for each subject. Daily 24-hr ambient PM₁₀ and PM_2.5 concentrations were measured at five fixed sites spaced throughout the study region. SO₄ ^2-, which is found almost exclusively in the fine particle fraction and which does not have major indoor sources, was measured in all PM_{2 5} samples as an indicator of accumulation mode particu-late matter of ambient origin.     

Development of a 24-Hour Method for Analysis of SO2 and CO2 from Electric Utility Units Equipped with Flue Gas Desulfurization Scrubbers

A procedure was developed for the 24-h determination of SO₂ and CO₂ in effluent gas from fossil fuel combustion sources. Laboratory experiments were conducted to test absorption of SO₂ in hydrogen peroxide solution and absorption of CO₂ by sodium hydroxide on an inert substrate at expected ambient temperatures of 15 to 45°C. Isopropyl alcohol cannot be used to trap sulfuric acid and particulates because it permeates the sampling train and prevents complete absorption of CO₂. Elemental analysis of stack particulates revealed that at least 31 elements were present. Iron and other elements interfered with SO₂ analysis. These particulates were completely removed by a heated borosilicate glass filter. Both laboratory and field experiments showed that molecular sieves are a promising alternative for CO₂ absorption. Statistical evaluation of data collected at three units equipped with flue gas desulfurization scrubbers proved that the new procedure is accurate and precise.     

Use of a Continuous Nephelometer to Measure Personal Exposure to Particles During the U.S. Environmental Protection Agency Baltimore and Fresno Panel Studies

ABSTRACT

In population exposure studies, personal exposure to PM is typically measured as a 12- to 24-hr integrated mass concentration. To better understand short-term variation in personal PM exposure, continuous (1-min averaging time) nephelometers were worn by 15 participants as part of two U.S. Environmental Protection Agency (EPA) longitudinal PM exposure studies conducted in Baltimore County, MD, and Fresno, CA. Participants also wore iner-tial impactor samplers (24-hr integrated filter samples) and recorded their daily activities in 15-min intervals. In Baltimore, the nephelometers correlated well (R² = 0.66) with the PM₂₅ impactors. Time-series plots of personal nephelometer data showed each participant's PM exposure to consist of a series of peaks of relatively short duration. Activities corresponding to a significant instrument response included cooking, outdoor activities, transportation, laundry, cleaning, shopping, gardening, moving between microenvironments, and removing/putting on the instrument. On average, 63-66% of the daily PM exposure occurred indoors at home (about 2/3 of which occurred during waking hours), primarily due to the large amount of time spent in that location (an average of 7277%). Although not a reference method for measuring mass concentration, the nephelometer did help identify PM sources and the relative contribution of those sources to an individual's personal exposure.     

Ozone Regimes in or near Forests of the Western United States: Part 2. Factors Influencing Regional Patterns

Abstract

Ozone levels in or near forests of the western United States resulted from transport of ozone from urban areas, photochemical formation of ozone in nonurban areas from either natural or manmade precursors, and downward mixing of ozone from the tropospheric reservoir. Similarities in ozone exposure regimes were clearly associated with ozone characteristics, such as the shape of the diurnal curve in hourly ozone concentrations and the magnitudes of ozone levels. No single site characteristic dominated across the region. Eight classes of ozone regimes were identified: largeurban, medium-urban, small-urban, urban downwind-urban, urban-transport, rural, rural-remote, and remote. Sites in the western United States can be classified according to these classes. Of the sites included in the analysis, Olympic National Park, Colorado National Monument, Redwood National Park, Grand Canyon, and Crook County in Oregon showed the lowest impact from urban-generated ozone. The greatest impact of manmade ozone was found in forests of southern and central California, and to some extent in Rocky Mountain National Park and along the western slopes of the Cascades in Washington.

The eight groups of sites showing similar ozone exposure regimes as identified by Böhm et al.¹ corresponded closely with the eight classes of ozone regimes, indicating that regional similarities in ozone exposure regimes can be linked to ozone formation and transport processes despite a lack of geographic cohesion. Sixty-four percent of variance in ozone exposure regimes can be expressed in a twodimensional space called diurnal-curve space. Group membership is more cohesive in diurnal-curve than geographic space. Applications of diurnal-curve space include (1) a sensitive regional analysis of the nature and magnitudes of ozone exposure regimes in or near western forests; (2) a pro-active means for identifying sites with changing ozone exposure regimes; and (3) guidelines from which biologists can develop realistic experimental fumigation protocols. It is suggested that univariate statistics, such as 7-hour mean, 24-hour mean, SUM06, and SUM08, cannot identify up to 39% of the variance in ozone exposure regimes among sites in or near forests of the western United States.     

Response of the bacteria and fungi of two soils to the sulfonylurea herbicide cinosulfuron.

Changes in aerobic bacteria and autotrophic nitrifier numbers, and in respiration and nitrification in two soils treated with cinosulfuron at 42 (field rate) and 4200 microg/kg were studied after 1 and 4 weeks of incubation under laboratory conditions. Only nitrification at 1 week was slightly inhibited by the cinosulfuron treatment, even at the field rate. In vitro toxicity tests carried out in agar media on representative aerobic bacteria, fungi and Azotobacter strains isolated from the two soils, as well as on nine collection soil bacteria, showed that only a very high cinosulfuron concentration (100 mg/l) can have negative effects on the growth of a limited number of soil heterotrophic microorganisms, under conditions similar to those of soil environment. The absence of three branched-chain amino acids increased bacterial sensitivity, thus showing the importance of the chemical conditions and suggesting acetolactate synthase enzyme blockage as the toxicity mechanism. It is concluded that cinosulfuron has a negative effect on only a few aspects of the microbial community in soil ecosystems, even at concentrations higher that those currently in use.     

Response of needle sulphur and nitrogen concentrations of Scots pine versus Norway spruce to SO2 and NO2

The results of two field studies and an open-top chamber fumigation experiment showed that the response of mature Scots pine to SO(2) and NO(2) differed from that of mature Norway spruce. Moreover, the response of pine seedlings to SO(2) and NO(2) differed from that of mature trees. The greater increase in the needle total S concentrations of pine suggested more abundant stomatal uptake of SO(2) compared to spruce. Both pine seedlings and mature trees also seemed to absorb more N from atmospheric deposition. Mature pine was able to assimilate SO(4)(2-) derived from SO(2) into organic S more effectively than mature spruce at the high S and N deposition sites, whereas both pine and spruce seedlings accumulated SO(4)-S under NO(2)+SO(2) exposure. Spruce, in turn, accumulated SO(4)-S even when well supplied with N. Net assimilation of SO(4)(2-) in conifer seedlings was enhanced markedly by elevated temperature. To protect the northern coniferous forests against the harmful effects of S and N deposition, it is recommended that the critical level for SO(2) as a growing season mean be set at 5-10 microg m(-3) and NO(2) at 10-15 microg m(-3), depending on the 'effective temperature sum' and/or whether SO(2) and NO(2) occur alone or in combination.     

Note on a System to Evaluate the Influence of Chronic Exposure to CO on the Hatching Eggs of the White Leghorn Chicken

It has become increasingly apparent that there exists a need for evaluating the well-being of embryos subjected to chronic doses of CO during gestation. Baily¹ and Hadden,² for example, have reported that maternal cigarette smoking resulted in a significant decrease in infant birth weight. It is obvious, however, that the presence of other pharmacologically toxic substances in cigarette smoke besides carbon monoxide may have been significant. A problem in using the developing mammalian embryo as a model for studying the effects of such agents is that the physiological responses of the mother may afford some measure of protection to the developing fetus. This is not the case in oviparous development because there is no connection between mother and embryo.     

Exposure to mixture of heavy metals and muscle strength in children and adolescents: a population-based study

Environmental Science and Pollution Research - Human beings are exposed to heavy metals through various ways in daily life. However, the effect of heavy metal mixtures on muscle strength in...     

Exposure to trace elements of flamingos living in a biosphere reserve, the Camargue (France)

Recent research has shown that some adult flamingos Phoenicopterus roseus collected from the Camargue Biosphere Reserve had tissue metal concentrations considerably higher than the average for this species. As the range of these birds is large, the origin of the contamination was unknown. Blood and feather samples from nestling flamingos were therefore analysed for trace metals to determine the presence and origin of local contamination. A comparison of elemental concentration in the feathers of nestling and adult flamingos revealed higher concentrations of Cd, Cu, Pb and Se in adults, and higher concentrations of Zn in juveniles. This was attributed to increased exposure to atmospheric pollutants of adults, and either differences in Zn requirements and metabolism between adults and juveniles, or a local contamination of the juveniles' food supply by Zn. Concentrations of Zn in serum were also very elevated compared with human standards. Cd, Cu, Zn and Se concentrations were analysed in outer (O) and inner (I) barbs (i.e. barbs that are, respectively, exposed or not exposed to external deposits) of greater coverts of nestling flamingos. A comparison of elemental concentrations in these two feather components indicates a local atmospheric contamination by Cd, Cu and Pb.     

2种苔藓的叶绿素荧光特性及耐受性对Pb2+浓度的响应

在不同pbz+质量浓度(0、25、50、100、200 mg/L)的人工条件下,利用叶绿素荧光动力学技术研究比较了狭叶扭口藓(Barbula subcontorta Broth.)和地钱(Marchantia polymorpha L.)的叶绿素荧光特性.结果表明:(1)总体上,随着Pb2+浓度的增加,狭叶扭口藓和地钱...     

Response of the lichen Cladonia rei Schaer. to strong heavy metal contamination of the substrate

The phenomenon of mass occurrence of the lichen Cladonia rei in extremely contaminated post-smelting slag dumps was studied in relation to metal accumulation capacity of this lichen. The research was aimed to evaluate the relationships between element contents in the thalli and in the corresponding substrate. The study was conducted in terms of a wide spectrum of Zn, Cd, Pb and As contents. The concentrations of these elements in the lichen thalli and substrate samples were measured. Various regression models were considered to find the best fitted one that greatly reflects the dependencies. Various Cladonia species and the hyperaccumulator Diploschistes muscorum were also included in the study for comparison purposes. Specific non-linear regression models described by a power function reflected relationships between Zn and Cd contents in C. rei thalli and in the host substrate in the most reliable way. The relationship for As was also noted, but none significant model was found. Contrarily, Pb concentrations in the thalli varied independently of the metal levels in the substrate. Nevertheless, the concentrations of all measured heavy metals in C. rei thalli are relatively low considering the frequently enormous substrate contamination. Different Cladonia species demonstrated a generally similar accumulation capacity and could be considered as weak accumulators. The restrained accumulation pattern may be one of the important attributes of C. rei which facilitates its colonisation of extremely contaminated dumps. This finding highlights ecological importance of this species as stable and resistant pioneer in such affected sites.     

Response of a grassland ecosystem to air pollutants. VI. The chemical climate: concentrations and potential flux densities of relevant criteria pollutants

Of the so-called criteria air pollutants, ozone (O3) and sulfur dioxide (SO2) are relevant to agriculture due to their known toxic (O3, SO2) and fertilizing (SO2) potentials. A proper entity to describe pollutant doses in dose-response relationships is the cumulative flux density absorbed by the respective receptor systems. For nutrient budgets the whole ecosystem acts as receptor; for toxicological considerations, stomatal uptake has to be considered primarily. In Central Europe, the atmospheric inputs of oxidized S (SO2, SO3(2-) and SO4(2-)) have declined from the past, and at present are generally below the nutrient requirements of agroecosystems. In contrast, the phytotoxic potential of O3 has increased during the last decade. Pollutant absorbed doses and weighted concentrations were used to describe the risk potential. It could be shown that these two differ significantly.     

Evaluation of Human Exposure to Ambient PM10 in the Metropolitan Area of Mexico City Using a GIS-Based Methodology

ABSTRACT

The main goal of this study was to evaluate the magnitude of outdoor exposure to fine particulate matter (PM₁₀) potentially experienced by the population of metropolitan Mexico City. With the use of a geographic information system (GIS), spatially resolved PM₁₀ distributions were generated and linked to the local population. The PM₁₀ concentration exceeded the 24-hr air quality standard of 150 μg/m³ on 16% of the days, and the annual air quality standard of 50 μg/m³ was exceeded by almost twice its value in some places. The basic methodology described in this paper integrates spatial demographic and air quality databases, allowing the evaluation of various air pollution reduction scenarios. Achieving the annual air quality standard would represent a reduction in the annual arithmetic average concentration of 14 μg/m³ for the typical inhabitant. Human exposure to particulate matter (PM) has been associated with mortality and morbidity in Mexico City; reducing the concentration levels of this pollutant would represent a reduction in mortality and morbidity and the associated cost of such impacts. This methodology is critical to assessing the potential benefits of the current initiative to improve air quality implemented by the Environmental Metropolitan Commission of Mexico City.     

Response of foodborne Salmonella spp. marker strains inoculated on egg shell surfaces to disinfectants in a commercial egg washer.

The objective of this study was to determine the effectiveness of an iodine based disinfectant (IBD, Iocide, Biomedical Development Corporation, San Antonio, TX) on Salmonella enteritidis and S. typhimurium inoculated on egg shell surfaces under simulated industry egg processing conditions with a commercial egg washer used as the sanitizer delivery system. Re-circulated egg washer water containing 1.40-2.85 g/l total dissolved solids was obtained from a commercial egg processing. Sanitizing treatments consisted of distilled deionized water (DDW), IBD, and chlorine (CL; 200 ppm). All treatments (DDW, IBD and CL) significantly (p < 0.05) decreased Salmonella spp. populations on the shell compared to dry (no spray) egg controls. However, efficacy of egg sanitizers appeared to be dependent on the level of total dissolved solids in the egg wash water.     

An Air Quality Data Analysis System for Interrelating Effects,Standards, and Needed Source Reductions: Part 11. A Lognormal Model Relating Human Lung Function Decrease to O3 Exposure

Forced expiratory volume in 1 second (FEV1) was measured in 21 men exercising while exposed to four O₃ concentrations (0.0,0.08,0.10, and 0.12 ppm). A lognormal multiple linear regression model was fitted to their mean FEV1 measurements to predict FEV1 percent decrease as a function of O₃ concentration and exposure duration. The exercise level used was probably comparable to heavy manual labor. The longest O₃, exposure studied was 6 h. Extrapolating cautiously to an 8-h workday of heavy manual labor, the model predicts that O3 concentrations of 0.08, 0.10, and 0.12 ppm would decrease FEV1 by 9,15, and 20 percent, respectively.