Abstract  U.S. Environmental Protection Agency. Fine particulate matter (PM) in urban atmospheres contains substantial amounts of semi-volatile material (e.g. animonium nitrate and semi-volatile organic compounds), some of which is lost when PM is sampled with a filter. This study addresses the hypothesis that the concentration of fine PM will be significantly underestimated in urban environments using the PM2.5 Federal Reference Method (FRM) because of the loss of semi-volatile material from the particles during and after sampling. Moreover, these losses will be substantial in environments where significant concentrations of semi-volatile PM are present. It is further postulated that fine PM mass, including the semi-volatile fine PM species, is an appropriate surrogate for the components of fine particles which have been associated with observed mortality and morbidity effects in epidemiological studies. The underestimation of the semi-volatile species will tend to over emphasize the importance of non-volatile fine PM components such as sulfate. There is a need for real-time and week-long sampling methods, as well as 24-hour methods, all of which accurately measure PM2.5, including the semi-volatile constituents animonium nitrate and semi-volatile organic material.

Abstract  1. The pulmonary toxic events induced by acute nitrogen dioxide (NO)2 exposure were studied in the rat to develop an inhalation model to investigate therapeutic measures. 2. A good correlation was observed between the lung weights and severity of the atypical pneumonitis. The pulmonary effects observed, became more pronounced with increasing NO2 concentrations (0, 25, 75, 125, 175 or 200 ppm, 1 ppm NO2 = 1.88 mg m-3 NO2) and exposure times (5, 10, 20 or 30 min). 3. An adequate NO2 concentration is 175 ppm, because it can induce a severe lung injury without mortality. This makes it possible to investigate suitable therapeutic interventions for several days. 4. Following acute inhalatory NO2 intoxication, transformation of NO2 to nitrate is presumably more notable than transformation to nitrite. 5. The transformation of NO2 to nitrate in lung tissue causes a slight increase in the serum nitrite concentration, which does not induce measurable formation of methaemoglobin. 6. Presumably, methaemoglobin does not contribute to the toxicity of NO2 intoxication.

Abstract  South Coast Air Quality Management District. #Many epidemiological studies provide evidence of an association between airborne particles, measured as PM10 (particulate matter less than 10 Ám in diameter), and daily morbidity and mortality. Most of these studies have been conducted in urban areas where PM10 consists primarily of fine particles (<2.5 Ám in diameter). Few studies have investigated impacts associated with coarse mode particles (>2.5 Ám in diameter). We investigated associations between PM10 and daily mortality in the Coachella Valley, a desert resort and retirement area east of Los Angeles, where coarse particles of geologic origin typically comprise approximately 50-60% of PM10 and can exceed 90% during wind events. Our analysis utilized daily data on mortality from 1989 through 1992 as well as several pollutant and meteorological variables, including PM10, nitrates, sulfates, ozone, nitrogen dioxide, carbon monoxide, temperature, and relative humidity. Outcome variables included several measures of daily mortality, including all-cause, cardiovascular and respiratory mortality, and counts of deaths for those above age 50. Multivariate Poisson regression models were used to explain these health endpoints, controlling for temperature, humidity, day of the week, season, and time, using locally weighted smoothing techniques. The analysis indicated statistically significant associations between PM10 (2- or 3-day lags) and each measure of mortality. The results were robust to various model specifications, correction for autocorrelation and overdispersion, and analysis of influential observations. A 10 Ág/m3 change in daily PM10 was associated with an approximately 1% increase in mortality, which is of similar magnitude to particle-associated impacts identified in urban areas. Thus, our findings provide evidence for a mortality effect of PM10 in an area where the particulate mass is dominated by coarse particles.

Abstract  The alveolar burden following nose-only aerosol exposure of rodents to highly toxic radioactive materials depends upon the percentage of the inhaled aerosol that is deposited beyond the animals' ciliated epithelium. The quantity inhaled was estimated from the product of the aerosol concentration (nCi/liter), the exposure time (minutes) and the mean minute volume (liter/min) of the animals. For rats exposed to Pu(NO3)4 and sacrificed within an hour, the mean alveolar deposition was 19.2 plus or minus 9.19% for 36 groups of both -239Pu and -238Pu. No important correlations between any of the measured parameters and this initial percentage deposition were observed, in contrast with the results for -239PuO-2 deposition measured in rats sacrified 24 or 48 hours postexposure. In these, the aerosol activity median aerodynamic diameter (AMAD) was strongly correlated with aerosol concentration and percentage deposition (mean-7.9 plus or minus 3.9% for 32 groups) with AMAD over the range of 1.5 to 4.5 mum. The 200-fold lower mass concentration of -238Pu compared with -239Pu for a given activity level may explain the fact that the AMAD was correlated with concentration for -239Pu oxide and nitrate, but not for -238Pu compounds.

Abstract  It is hypothesized that higher indoor nitrogen dioxide levels cause diarrhoea in infants and that this is the result of a direct action of oxides of nitrogen on the gut. This hypothesis is tested by reviewing the reported association between methaemoglobin and diarrhoea in children and two recent reports on indoor air and diarrhoea in infants. The collection of further empirical data is now needed. Studies which measure indoor levels of nitrogen dioxide could usefully collect data on infants symptoms that are not exclusively respiratory. Similarly, studies which are collecting diary information on children's health symptoms should consider collecting data on indoor air quality with respect to the oxides of nitrogen.

Abstract  Previous field and laboratory studies with vascular plants have shown that perchlorate is transported from perchlorate fortified soils and is accumulated in the plant tissues and organs. This paper contains results of preliminary investigations on the occurrence of perchlorate in tobacco plants grown in soils amended with a fertilizer whose nitrogen content is derived from naturally occurring sodium nitrate (Chile saltpeter). Ion chromatography (IC) and capillary electrophoresis (CE) were used for quantitative analysis, while nuclear magnetic resonance (NMR) spectroscopy was used for qualitative analysis of perchlorate. Results show that perchlorate is accumulated by tobacco plants into the leaves from soils amended with fertilizers that contain perchlorate. Also, perchlorate can persist over an extended period of time and under a variety of industrial processes as shown by its presence in off-the-shelf tobacco products including cigarettes, cigars, and pouch and plug chewing tobaccos in concentrations ranging from nd to 60.4 +/- 0.8 mg/kg on a wet weight basis.

Abstract  Dimethylamine is important because it is a precursor of nitrosodimethylamine, a suspected carcinogen in man. Significant quantities of dimethylamine and nitrite are found in gastric fluid, and conditions in the stomach are favorable for nitrosodimethylamine formation. Little is known about the origins of dimethylamine in gastric fluid. Studies were performed to determine whether dimethylamine can be transported from blood to gastric fluid. There was no diurnal variation of the dimethylamine content in gastric fluid or blood from untreated dogs. We administered 50 mg/kg dimethylamine i.v. to dogs and ferrets and collected blood and gastric fluid samples at timed intervals. In both species we observed similar kinetics of dimethylamine distribution into biologic fluids. Dimethylamine concentrations in blood and gastric fluid rose rapidly during the first minutes after treatment. Blood dimethylamine concentrations peaked within 30 min after the dose (rising from 10 to 430 nmol/ml in the dogs, and from 30 to 430 nmol/ml in the ferrets). Dimethylamine concentrations in blood slowly decreased thereafter. Gastric fluid dimethylamine concentrations continued to rise for 3 h after the dose (from 40 to 540 nmol/ml in the dogs, and from 40 to 1056 nmol/ml in the ferrets). Gastric fluid dimethylamine remained elevated for more than 5 h. Between 1 h and 5 h after treatment, gastric fluid dimethylamine concentrations were significantly higher than blood dimethylamine concentrations (by greater than 2.5 X). In gastric fluid from control animals, dimethylamine concentration exceeded monomethylamine concentration, which in turn was higher than trimethylamine concentration. Administration of dimethylamine transiently increased gastric fluid monomethylamine content, but had little effect upon trimethylamine concentration. These data demonstrate that dimethylamine is efficiently transported from blood into gastric fluid.

Abstract  Weanling male Wistar strain rats were administered, through the drinking water, nitrite (0.2%) and dimethylamine (DMA) (0.2%), either singly or in combination for 9 months. Some animals also received 0.5% butylated hydroxytoluene (BHT) in the diet. Nitrite, as well as DMA, caused higher in vitro lipoperoxidation, free lysosomal enzyme activities and cytosolic superoxide dismutase activity in liver. Some of these increases viz., the enzyme activities in liver, were counteracted to a significant extent in the rats receiving a dietary supplement of BHT. The results indicate that nitrite and DMA may induce toxicity through some free radical reactions and that BHT can provide some protection.

Abstract  Groups of mice were treated per os with sodium nitrite either alone or in combination with nitrosatable amino compounds and tested in the host mediated assay. When mice were treated with sodium nitrite in combination with dimethylamine a small(4-fold) but significant increase in mutant frequency (MF) was observed. Ethylurea or methylurea in combination with sodium nitrite induced 10- or 850-fold increases in MF, respectively. The response to methylurea was dose-dependent with a 6- and 30-fold increase in MF at 5.4 and 11.5 mg/kg NaNO2 and a 6-fold increase at 108 mg/kg methylurea. That this response reflected gastric nitrosation was shown by the disappearance of the response if NaNO2 administration preceded methylurea treatment by 10 min. High MF's were observed if NaNO2 was administered 10 or 20 min after methylurea.

Abstract  It is a well-known fact that dimethylnitrosamine (DMNA) causes the formation of liver cancer. And it is also recognized that DMNA is generated from dimethylamine in food and nitrite, a food additive, and that it is produced secondarily in the stomach. But there is a report that shows that albino rats practically given dimethylamine and sodium nitrite have developed no cancer. Therefore, in order to see whether the report is right or not, the present authors kept albino rats for 78 days giving them various degrees of concentration of sodium nitrite and dimethylamine solutions diluted with drinking water. As the result, no formation of tumours was found in the livers of those rats. But the decrease in the vitamin A content of their livers was observed, which suggested the disturbance of the liver function. Then in expectation of the probability that a longer period of administration of sodium nitrite and dimethylamine and a higher concentration of sodium nitrite might develop liver cancer, the authors kept rats for 410 days giving them higher concentrations of sodium nitrite (15 g/l and 30 g/l) as well as an ordinary concentration of it (5 g/l ), together with dimethylamine. The rats given sodium nitrite at higher concentrations died of methaemoglobinemia in a week or two, but the ones given at an ordinary concentration survived. One rat died on the 318th day, in whose liver a tumour was observed to have grown. Some tumours were also found in the spleen and the mesentery, which are considered to be metastatic tumours. One of the animals killed on the 410th day was found to have developed a tumour in the liver alone, which suggests that these tumours were liver-idiopathic. These tumours are conjectured through a pathohistological examination to be fibrous sarcomata of vascular origin. Judging from these results, the warning that these substances in food, i.e. dimethylamine and sodium nitrite, when they are ingested for a long time regardless of their quantities, will possibly cause the development of tumours in the liver cannot be disregarded.

Abstract  The cardiovascular system is currently considered a target for particulate matter, especially for ultrafine particles. In addition to autonomic or cytokine mediated effects, the direct interaction of inhaled materials with the target tissue must be examined to understand the underlying mechanisms. In the first approach, pulmonary and systemic distribution of inhaled ultrafine elemental silver (EAg) particles was investigated on the basis of morphology and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Rats were exposed for 6 hr at a concentration of 133 Ág EAg m3 (3 * 106 cm3, 15 nm modal diameter) and were sacrificed on days 0, 1, 4, and 7. ICP-MS analysis showed that 1.7 Ág Ag was found in the lungs immediately after the end of exposure. Amounts of Ag in the lungs decreased rapidly with time, and by day 7 only 4% of the initial burden remained. In the blood, significant amounts of Ag were detected on day 0 and thereafter decreased rapidly. In the liver, kidney, spleen, brain, and heart, low concentrations of Ag were observed. Nasal cavities, especially the posterior portion, and lung-associated lymph nodes showed relatively high concentrations of Ag. For comparison, rats received by intratracheal instillation either 150 ÁL aqueous solution of 7 Ág silver nitrate (AgNO3) (4.4 Ág Ag) or 150 ÁL aqueous suspension of 50 Ág agglomerated ultrafine EAg particles. A portion of the agglomerates remained undissolved in the alveolar macrophages and in the septum for at least 7 days. In contrast, rapid clearance of instilled water-soluble AgNO3 from the lung was observed. These findings show that although instilled agglomerates of ultrafine EAg particles were retained in the lung, Ag was rapidly cleared from the lung after inhalation of ultrafine EAg particles, as well as after instillation of AgNO3, and entered systemic pathways.

Abstract  HEEP COPYRIGHT: BIOL ABS. Measurements of NH3, HNO3 and particulate nitrate were made at urban sites in Commerce City, Colorado, and Warren, Michigan, and at rural locations near Abbeville, Louisiana, and Luray, Virginia (USA). The average NH3 and HNO3 concentrations over all sites were 1.7 and 0.7 ppb, respectively. Diurnal patterns, determined at the Abbeville site, suggested a photochemical mechanism for the production of HNO3 and local sources for NH3. Seasonal data collected in Warren, Michigan, showed NH3 concentrations were lowest in the winter. This was caused by the temperature dependence of the ammonium nitrate equilibrium constant. NH3 and HNO3 concentrations at the other sites were not in agreement with the concentrations predicted from the ammonium nitrate equilibrium constant.

Abstract  Electric Power Research Institute; U.S. Department of Energy. #Because dry-deposition inputs are difficult to measure, they are often ignored in biogeochemical studies. In this study three separate methods were used to estimate dry deposition of nitrate to a deciduous forest (Walker Branch Watershed) in eastern Tennessee. The range of estimates of dry-deposition flux was from 1.8 to 9.1 kg NO-/3-N ha-1 yr-1. Using a hybrid approach that combines some aspects of all three methods. a best estimate of 4.8 kg NO-/3-N ha-1 yr-1 was derived. About 75% of this flux is attributable to deposition of HNO3 vapor with large particles contributing most of the remainder; the contribution from small particles is negligible. The range of estimates obtained from the three techniques suggest that dry-deposition measurements should be interpreted with caution. Our best estimate indicates that dry deposition of NQ is the largest single form of inorganic nitrogen (N) deposition to this forest, contributing almost half of the 10.1 kg N ha-1 total annual input. All of the enhancement of NQ deposition in stemflow and throughfall relative to incident precipitation can be explained by washoff of dry-deposited NO-/3, and some canopy uptake of dry-deposited NO-/3 is suggested. This uptake occurs primarily during the growing season and contributes from 0.2 to 7.5 kg N ha-1 yr-1 to the N requirements of the ecosystem, with a best estimate of 3.2. Despite the uncertainties, the magnitude of the potential input fluxes to forested ecosystems necessitates consideration of nitrate dry deposition in ecosystem nitrogen cycling studies.

Abstract  Quantitation of trace levels of perchlorate ion in water has become a key issue since this species was discovered in water supplies around the United States. Although ion chromatographic methods presently offer the lowest limit of detection, "approx"40 nM (4 ng ml -1 ), chromatographic retention times are not considered to be unique identifiers and often cannot be used in legal proceedings without confirmatory testing. Mass spectrometry can provide such confirmation; however, detection capabilities can impose a practical limitation on its use. Moreover, quadrupole mass spectrometers cannot provide sufficient accuracy and precision in m/z to identify conclusively an ion as perchlorate when samples are run directly without prior chromatographic or electrophoretic separation. We report on the abilities of (1) tetralkylammonium cations and (2) minimally nucleophilic, sterically hindered organic bases to increase selectivity in the electrospray ionization mass spectrometric (ESI-MS) determination of perchlorate ion without concomitant loss of sensitivity. Selectivity arises from the formation of a stable association complex between a base molecule and a perchlorate anion. The best results were obtained using 10 ÁM chlorhexidine in methanolic solution; the lower limit of detection (LLOD) for S/N>/=2 was less than or equal to 0.10 ÁM (10 ng ml -1 ). This compares favorably with the LLOD determined for perchlorate in the absence of any complexing agents ("approx"0.05 ÁM=5 ng ml -1 ). For the other bases, which were diazabicyclo compounds (DBN, DBU, DBO), sensitivity was lower by 90% or more. The chlorhexidine-perchlorate complex (m/z=605) can be observed even in the presence of equiformal nitrate, nitrite, hydrogensulfate, chloride, bromide, bromate, and chlorate (all together) down to approximately 1 ÁM; thus, the method is rugged enough to find application to systems containing multiple inorganic anions.

Abstract  Spent regenerant brine from ion-exchange technology for the removal of perchlorate and nitrate produces a high salt waste stream, which requires remediation before disposal. Bioremediation is an attractive treatment option. In this study, we enriched for salt tolerant bacteria from sediments from Cargill salt evaporation facility (California, USA), the Salton Sea (California, USA), and a high density hydrocarbon oxidizing bacterial cocktail. The bacterial cocktail enrichment culture reduced ClO4- from 500 to 260 mg 1 in 4 weeks. Salt tolerant bacterial isolates from the enrichment cultures and two denitrifying salt tolerant bacteria, Haloferax denitrificans and Parococcus halodenitricans, substantially reduced perchlorate. The highest rate of perchlorate removal was recorded with the isolate, Citrobacter sp.: 32% reduction in 1 week. This bacterium substantially reduced perchlorate in 0-5% NaCl solutions and maximally at 30 degrees C and at an initial pH 7.5. In simulated brines containing 7.5% total solids, the Citrobacter sp. significantly reduced both perchlorate and nitrate with 34.9 and 15.6% reduction, respectively, in 1 week. Coculture of a potent perchlorate reducing, non-salt tolerant (non-saline) bacterium, perclace and the Citrobacter sp. proved most effective for perchlorate removal in the brine (46.4% in 1 week). This study demonstrates that both anions can be reduced in treatment of brines from ion exchange systems.

Abstract  Nitric oxide (NO) is increased in exhaled air of asthmatics. We hypothesized that endogenous NO contributes to airway inflammation and hyperresponsiveness, and that interleukin-8 (IL-8) might be involved in this mechanism. In human transformed bronchial epithelial cells in vitro, NO donors increased IL-8 production dose-dependently. In addition, tumor necrosis factor-"alpha" (TNF-"alpha") plus IL-1"beta" plus interferon-"gamma" (IFN-"gamma") increased IL-8 in culture supernatant of epithelial cells; the combination of NO synthase (NOS) inhibitors, aminoguanidine (AG) plus NG-nitro-L-arginine methyl ester (L-NAME) attenuated the cytokine-induced IL-8 production in epithelial cells. In guinea pigs in vivo, ozone exposure induced airway hyperresponsiveness to acetylcholine and increased neutrophils in bronchoalveolar lavage fluid (BALF), and these changes persisted for at least 5 h. Pretreatment with NOS inhibitors had no effect on airway hyperresponsiveness or neutrophil accumulation immediately after ozone, but significantly inhibited the changes 5 h after ozone. NOS inhibitors also attenuated the increases of nitrite/nitrate levels in BALF and the IL-8 mRNA expression in epithelial cells and in neutrophils in guinea pig airways 5 h after ozone. These results suggest that endogenous NO may play an important role in the persistent airway inflammation and hyperresponsiveness after ozone exposure, presumably partly through the upregulation of IL-8.

Abstract  U.S. Department of Agriculture Forest Service; U.S. Environmental Protection Agency. #The decline of red spruce (Picea rubens Sarg.) at high elevations in eastern North America has been linked in time and space with exposure to acidic cloud water. To investigate the below ground effects of a cloud water deposition gradient between two mature red spruce stands on the summit of Whitetop Mountain, Virginia, the chemistries of precipitation, throughfall, and soil solution were monitored over a 2-year period, and fine-root distributions were characterized. Deposition of water, sulfate, nitrate, and ammonium in throughfall and stemflow was from 15 to 55% greater at the site with greater exposure to cloud water deposition (high cloud site), depending upon the particular ion and year. Soil solution nitrate concentrations were highly variable over time, and base cation, Al, and H ion concentrations were highly correlated with nitrate in both organic and mineral horizons at both sites. Soil solution nitrate, base cation, Al, and H ion concentrations were two to six times greater during periods of low soil moisture in the summer-autumn of 1987 and 1988 than during the remainder of the study period. In the mineral soil solutions, the high cloud site had significantly higher (p < 0.001) concentrations of nitrate and Al, and significantly lower (p < 0.05) Ca:Al and Mg:AI ratios. The high cloud stand also had shallower root systems, with fine-root biomass less than 40% of that of the low cloud stand (p <0.05) at all depths greater than 18 cm. Soil solutions collected from below 15 cm at the high cloud site had a mean Ca:AI ratio less than 0.5 and Al concentrations that during dry periods, frequently approached or exceeded the literature values for the toxicity threshold for red spruce root growth. Restricted root development in the high cloud stand was apparently the result of this unfavorable chemical environment.

Abstract  Rabbits inhaled aerosols of hexavalent chromium (Na2CrO4) and trivalent chromium (Cr(NO3)3) at concentrations of 0.9 and 0.6 mg/m3 of the metal, respectively, for 4-6 weeks (5 days/week and 6 hr/day). Significantly more macrophages were obtained from the lungs of rabbits exposed to Cr(VI) but not from rabbits exposed to Cr(III) as compared with the controls. Macrophages from rabbits exposed to Cr(III) showed several conspicuous changes. About one-third of the macrophages contained round dark inclusions, 0.5-1.5 micron diameter, rich in chromium. Most cells had very large lysosomes which contained membranous fragments of different sizes surrounded by a more homogeneous matrix. Laminated inclusions similar to the lamellar bodies in the type II cells increased in number as did the percentage of cells with a smooth cell surface. Also macrophages from rabbits exposed to Cr(VI) showed morphological changes. The most pronounced one was enlarged lysosomes which contained short lamellae and electron-dense patchy inclusions. Only Cr(III) produced functional changes of the macrophages. The metabolic activity measured by reduction of nitroblue tetrazolium was increased and the phagocytic activity reduced.

Abstract  Enzymatic denitrification of 2-nitropropane (2NP) was investigated in an NADPH-dependent hepatic microsomal system from male CD1 mice. The involvement of cytochrome P-450 (P-450) as the catalyst in 2NP denitrification was revealed by the induction of nitrite-releasing activity following phenobarbital (PB) pretreatment, by a decrease in activity with carbon tetrachloride pretreatment, by the inhibition of the reaction with classical P-450 inhibitors, and by the observation of a type I binding spectrum. Under optimal conditions, two pH-dependent peaks of activity were observed at pH 7.6 and pH 8.8, each with its own optimal substrate concentration. Inhibition of the reaction by metyrapone and carbon monoxide (CO) (among others) produced differential responses dependent on pH. These results, along with two pH optima and two substrate optima, suggested the involvement of multiple P-450 isozymes. Average specific activities were 8.05 nmoles of nitrite released per minute per milligram microsomal protein at pH 7.6 and 6.44 nmoles of nitrite released per minute per milligram microsomal protein at pH 8.8. Acetone was identified as the second product of the reaction by gas chromatography/mass spectrometry (GC/MS). Stoichiometry studies indicated that the acetone production was slightly less than expected (about 70%) from nitrite release. Up to 25% residual activity was observed under anaerobic conditions. These results suggested that though the predominant reaction mechanism was oxidative, oxygen-independent metabolism of 2NP also occurred to some extent. In contrast to the reported lack of activity in untreated rat, the observed denitrification in uninduced mouse liver microsomes was significant and suggested that major species-specific differences exist in the in vitro metabolism of 2NP.