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At least 487 records · Page 27Linked to original sources
PubMed1984

The induction of sister chromatid exchanges by environmental pollutants: relationship of SCE to other measures of genetic damage.

Sister chromatid exchanges (SCEs), induced by environmental pollutants from fossil fuel use, were measured in 2 cell systems, Chinese hamster ovary (CHO) cells and Chinese hamster primary lung cell cultures. The frequency of SCEs induced in these cell systems was related to other measures of genetic damage, namely mutations in CHO cells at the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) gene locus and in bacteria (Salmonella mutagenicity test TA-98), produced by the same pollutants. The pollutants were divided into 2 classes: those produced in oxidizing combustion environments--extracts of particles from light-duty diesel cars, spark-ignition cars, and an automotive tunnel; and those produced in reducing environments--extracts from coke oven mains and condensates from a low BTU coal gasifier obtained either before or after cleanup of the process stream. Sister chromatid exchanges were induced by all pollutants without the addition of a rat liver microsomal fraction (S-9 mix), whereas S-9 mix was required to induce a positive response in the CHO/HGPRT assay for all pollutants. The pollutants produced in a reducing environment required metabolic activation by S-9 mix to be mutagenic in the Salmonella mutation assay. The addition of S-9 mix to pollutants produced in an oxidizing environment reduced the response in the Salmonella test. The relative genotoxic potency for each pollutant was determined for all 3 endpoints. The slopes of dose-response curves for each pollutant were plotted for each assay to compare relative potency. When the bacterial mutagenicity test was compared to either mammalian cell assay, SCE or CHO/HGPRT, there was little correlation between relative potencies. However, the data indicated that the responses in the 2 mammalian cell assays, SCE and CHO/HGPRT, showed similar relative responses to the pollutants. Differences in the requirement for S-9 mix seem to be related to both the chemical nature of the mixture and the endpoint measured. Differences in responses are related not only to cell type but also to chemical composition of the complex pollutants.

Air Pollutants↗
PubMed2006

Oxidative decomposition of rhodamine B dye in the presence of VO2+ and/or Pt(IV) under visible light irradiation: N-deethylation, chromophore cleavage, and mineralization.

In order to make clear the roles of dissolved O2 in the photocatalytic decomposition of organic pollutants and to discriminate different degradation pathways (N-deethylation, chromophore cleavage, and mineralization) during the degradation of dye, the photodegradation of rhodamine B (RhB) has been investigated using vanadate and/or platinum species as electron acceptors in the presence or absence of O2 under visible light irradiation. It was found that with VO2+ as electron acceptor, RhB underwent efficient N-deethylation under visible light irradiation and O2 was found to slow down this process significantly. Little mineralization has been observed in the presence and absence of O2 in VO2+ systems. By contrast, Pt(IV) resulted in the cleavage of conjugated chromophore structure (bleaching) of RhB dye under the otherwise identical conditions. In this case, the presence of O2 did not affect the bleaching rate of the dye, but enhanced greatly the mineralization. Both cleavage of conjugated chromophore structure and N-deethylation occurred simultaneously upon the coaction of VO2+ and Pt(IV) under visible light irradiation. The mineralization yield of the combined system was evidently higher than the expected summation of separate ones. TOC, XPS, and ESR results indicate that in the VO2+ and Pt(IV) combined system VO2+ not only oxidized RhB leading to deethylation but also oxidized the reduced Pt(II) to regenerate Pt(IV) leading to the further cleavage of chromophore structure of RhB, which behaved quite different from the separate ones. A mechanism was also proposed to interpret the different pathways for the oxidative photodecomposition of RhB under visible irradiation.

Journal Article↗
PubMed2006

Microbial community of cyanobacteria mats in the intertidal zone of oil-polluted coast of Saudi Arabia.

Cyanobacterial mats are found at various locations along the coast of the Eastern Province of Saudi Arabia. Those mats were affected by severe oil pollution following 1991 oil spill. In this study, samples from Abu Ali Island were collected at three selected sampling sites across the intertidal zone (Lower, Middle, and Upper) in order to understand the effect of extreme environmental conditions of high salinity, temperature and desiccation on distribution of cyanobacteria along the oil polluted intertidal zone. Our investigation of composition of cyanobacteria and diatoms was carried out using light microscopy, and Denaturant Gradient Gel Electrophoresis (DGGE) technique. Light microscopy identification revealed dominant cyanobacteria to be affiliated with genera Phormidium, Microcoleus, and Schizothrix, and to a lesser extent with Oscillatoria, Halothece, and various diatom species. The analysis of DGGE of PCR-amplified 16S rRNA fragments showed that the diversity of cyanobacteria decreases as we proceed from the lower to the upper intertidal zone. Accordingly, the tidal regime, salinity, elevated ambient air temperature, and desiccation periods have a great influence on the distribution of cyanobacterial community in the oil polluted intertidal zone of Abu Ali Island.

Biodiversity↗
PubMed2002

Scaling of atmospheric mercury emissions from three naturally enriched areas: Flowery Peak, Nevada; Peavine Peak, Nevada; and Long Valley Caldera, California.

With the development of analytical capabilities that allow for almost real time measurement of mercury concentrations in air, the fluxes of mercury between environment compartments is being more carefully scrutinized. Recent advances have demonstrated that the mercury cycle is much more complicated than previously realized. This study quantified the mercury emissions from three areas with low levels of mercury enrichment associated with precious and base metal mineralization and recent volcanic/geothermal activity. Area emissions were calculated using Geographic Information System technology, and in situ derived mercury fluxes and those parameters found to statistically be dominant in controlling emissions. The most important controls on emission strengths were found to be geologic while environmental parameters such as light and temperature were found to drive the diel pattern typically observed for mercury emissions. Calculated area averaged emissions were 18.5, 10.0, and 13.6 ng/m2 h for the Flowery Peak, NV, Peavine Peak, NV, and Long Valley Caldera, CA areas, respectively. These emissions are an order of magnitude higher than values applied in global models for natural sources. This study, along with other recent work, demonstrates that natural sources may contribute more mercury than previously recognized to the atmospheric mercury pool.

California↗
PubMedDate not supplied

The effect of pH on the decomposition of hydrophenols in aqueous solutions by ultraviolet direct photolysis and the ultraviolet-hydrogen peroxide process.

The decomposition of catechol (o-hydrophenol) and resorcinol (m-hydrophenol) in aqueous solution by 254-nm UV direct photolysis and the UV-hydrogen peroxide (H2O2) process under various solution pH values was studied. The light absorbance and photolytic properties of catechol and resorcinol were found to be highly dependent on solution pH and can be adequately described with a three-species distribution model. For the UV-H2O2 process, the individual contribution to the decomposition of pollutants by direct photolysis and indirect hydroxyl radical destruction was differentiated by studying the linear addition of UV light absorbance of various reactant species. The contribution to the decomposition of the two hydrophenols by hydroxyl radical destruction was more than 95% in acidic and neural solutions for treatment with the UV-H2O2 process.

Catechols↗
PubMed2000

Air quality measurements from the Fresno Supersite.

The Fresno Supersite intends to 1) evaluate non-routine monitoring methods, establishing their comparability with existing methods and their applicability to air quality planning, exposure assessment, and health effects studies; 2) provide a better understanding of aerosol characteristics, behavior, and sources to assist regulatory agencies in developing standards and strategies that protect public health; and 3) support studies that evaluate relationships between aerosol properties, co-factors, and observed health end-points. Supersite observables include in-situ, continuous, short-duration measurements of 1) PM2.5, PM10, and coarse (PM10 minus PM2.5) mass; 2) PM2.5 SO4(-2), NO3-, carbon, light absorption, and light extinction; 3) numbers of particles in discrete size bins ranging from 0.01 to approximately 10 microns; 4) criteria pollutant gases (O3, CO, NOx); 5) reactive gases (NO2, NOy, HNO3, peroxyacetyl nitrate [PAN], NH3); and 6) single particle characterization by time-of-flight mass spectrometry. Field sampling and laboratory analysis are applied for gaseous and particulate organic compounds (light hydrocarbons, heavy hydrocarbons, carbonyls, polycyclic aromatic hydrocarbons [PAH], and other semi-volatiles), and PM2.5 mass, elements, ions, and carbon. Observables common to other Supersites are 1) daily PM2.5 24-hr average mass with Federal Reference Method (FRM) samplers; 2) continuous hourly and 5-min average PM2.5 and PM10 mass with beta attenuation monitors (BAM) and tapered element oscillating microbalances (TEOM); 3) PM2.5 chemical speciation with a U.S. Environmental Protection Agency (EPA) speciation monitor and protocol; 4) coarse particle mass by dichotomous sampler and difference between PM10 and PM2.5 BAM and TEOM measurements; 5) coarse particle chemical composition; and 6) high sensitivity and time resolution scalar and vector wind speed, wind direction, temperature, relative humidity, barometric pressure, and solar radiation. The Fresno Supersite is coordinated with health and toxicological studies that will use these data in establishing relationships with asthma, other respiratory disease, and cardiovascular changes in human and animal subjects.

Aerosols↗
PubMed1994

Rapid and sensitive pollutant detection by induction of heat shock gene-bioluminescence gene fusions.

Heat shock gene expression is induced by a variety of environmental stresses, including the presence of many chemicals. To address the utility of this response for pollutant detection, two Escherichia coli heat shock promoters, dnaK and grpE, were fused to the lux genes of Vibrio fischeri. Metals, solvents, crop protection chemicals, and other organic molecules rapidly induced light production from E. coli strains containing these plasmid-borne fusions. Introduction of an outer membrane mutation, tolC, enhanced detection of a hydrophobic molecule, pentachlorophenol. The maximal response to pentachlorophenol in the tolC+ strain was at 38 ppm, while the maximal response in an otherwise isogenic tolC mutant was at 1.2 ppm. Stress responses were observed in both batch and chemostat cultures. It is suggested that biosensors constructed in this manner may have potential for environmental monitoring.

Bacterial Outer Membrane Proteins↗
PubMedDate not supplied

High prevalence of sick building syndrome in a new air-conditioned building in Italy.

This study, which was conducted in central Italy, included (a) 525 office workers employed in an air-conditioned building that had fan coil units in every room (building B) and (b) 281 subjects who worked in three naturally ventilated buildings (building A) that were operated by the same public administration. The prevalence of work-related symptoms was assessed by a questionnaire that was administered by an occupational medicine specialist. The most frequent complaints of employees in building B were dry air, strong lighting, and high temperature. Employees who worked in this building experienced a statistically higher prevalence of symptoms that were characteristic of the sick building syndrome. This is the first time that this syndrome has been reported in Italy. Excessive illumination, a low relative humidity, and fiberglass on floors and furniture might have contributed to the symptoms. Inadequate maintenance of the building's air-conditioning plant and the employees' lack of information regarding self-regulation of the fan coil units may also have contributed to the prevalence of symptoms.

Air Conditioning↗
PubMed1994

Enhanced clastogenicity of contaminated groundwater following UV irradiation detected by the Tradescantia micronucleus assay.

The Tradescantia micronucleus (Trad-MCN) assay was used to determine clastogenic effects of contaminated groundwater collected near a hazardous waste landfill. Water samples were taken from a purification plant (activated charcoal filtration, UV irradiation) which was built to avoid groundwater contamination by this landfill. Five series of experiments were conducted during approximately 4 months. In addition, water samples were irradiated under laboratory conditions with increasing doses of UV light. Several field water samples gave positive, dose-dependent effects before filtration and irradiation. Maximal values (6.1 +/- 4.7 micronuclei (MCN)/100 tetrads) were six-fold above controls. UV irradiation of activated charcoal-filtered water resulted in an enhancement of MCN frequencies. Exposure of groundwater to UV irradiation in the laboratory led to a dose-dependent increase of micronuclei. At the highest dose (1500 J/m2) the MCN frequency was more than six times higher than in the unirradiated sample (5.4 +/- 1.0 vs. 0.8 +/- 0.4 MCN/100 tetrads). The clastogenicity of UV-irradiated samples decreased with a half-life of approximately 1 day. Irradiation of tap water did not increase the MCN frequency. Our results indicate that irradiation of water with UV light for disinfection purposes might lead to a transiently increased genotoxicity of chemically polluted water samples.

Hydrocarbons, Halogenated↗
PubMed2004

Metal behavior during vitrification of incinerator ash in a coke bed furnace.

In this study, municipal waste incinerator ash was vitrified in a coke bed furnace system and the behavior of metals was investigated. Coke and lime were added to provide heat which facilitated vitrification. Ash contributed more than 90% of metal (except for Ca) input-mass. Metal species with low boiling points accounted for the major fraction of their input-mass adsorbed by air pollution control devices (APCDs) fly ash. Among the remaining metals, those species with light specific weights in this furnace tended to be encapsulated in slag, while heavier species were mainly discharged by ingot. Meanwhile, the leachability of hazardous metals in slag was significantly reduced. The distribution index (DI) was defined and used as an index for distribution of heavy metals in the system. A high DI assures safe slag reuse and implies feasibility of recovering hazardous heavy metals such as Cr, Cu, Fe, Pb and Zn. The vitrification in a coke bed furnace proved to be a useful technology for the final disposal of MSW incinerator ash. The heavy metals are separated into the slag, ingot and fly ash, allowing safe reuse of the slag and possible recovery of the metals contained in the ingot and ash fractions.

Air↗
PubMed2006

The effect of solution pH and peroxide in the TiO2-induced photocatalysis of chlorinated aniline.

Chlorinated anilines are frequently used in the industry as starting materials for chemical synthesis. This type of compounds can end up as pollutants in wastewater. 2-Chloroaniline (2-ClA) was selected irradiating under monochromatic UV light at 300nm. The reaction rate could be enhanced by introducing low level of H(2)O(2) into the UV/TiO(2) system. Excess H(2)O(2) could not increase the HO* generation but retarded the reaction rate. The pH effect was also investigated in UV/TiO(2) and UV/TiO(2)/H(2)O(2) systems. All the experimental results show that pH is a sensitive parameter to the rate of degradation. Low reaction rate at acidic pH could be accounted by the dark adsorption test which has also proven the photocatalysis of TiO(2) may contribute to a two-step process: (1) 2-ClA pre-adsorbed onto TiO(2) and (2) photoexcitation of TiO(2). At high pH, rate enhancement could be observed at UV/TiO(2) system because of the increase generation of HO*. However, the introduction of H(2)O(2) slowdown the decay rate at such alkaline medium.

Adsorption↗
PubMed1981

Stomatal Response and Leaf Injury of Pisum sativum L. with SO(2) and O(3) Exposures : II. INFLUENCE OF MOISTURE STRESS AND TIME OF EXPOSURE.

Stomatal response during exposure to SO(2) and O(3) and subsequent leaf injury were examined in plants of Pisum sativum L. ;Alsweet' grown in a peat-vermiculite medium in controlled environment chambers. Plants developing under moisture stress, induced by drying the medium to 50% of field capacity, exhibited greater stomatal closure during exposures and less than one-fourth the necrosis compared to plants developing in a medium maintained at field capacity. Plants under moisture stress had only a slightly more negative plant water potential ( approximately -4.0 bars) than at field capacity ( approximately -3.4 bars). Plants exposed to pollutants for 2 hours near the beginning or end of a 16-hour light period had greater stomatal closure during exposures and less leaf necrosis than plants exposed during the middle of the light period.

Journal Article↗
PubMed1995

[A case control study of risk factors for Japanese cedar pollinosis].

Risk factors for Japanese cedar pollinosis including past or family history of allergic diseases, smoking and passive smoking, dwelling conditions, and life events were analyzed by a case control method. Patients with Japanese cedar pollinosis (22 males and 67 females) were matched with a corresponding number of patients without potential symptoms of pollinosis according to sex and age (+/- 5 years). The mean age was 39 years in both groups. The odds ratio (OR) was calculated by McNemar's method and the conditional logistic regression model. The design and methodology in this study were somewhat inadequate so that the validity of the results is limited. The most important problem was no-matching according to exposure to pollen. Significantly high OR for past history of allergic disease (8.80, 95% confidence interval (CI); 3.49-22.2), atopic sermatitis (9.00, 95% CI; 1.14-71.0), and a sibling history of allergic disease (3.25, 95% CI; 1.06-9.97) were consistent with former genetical studies. ORs were lower than unity for current smokers (0.36, 95% CI; 0.11-1.13) and those smoking 10 cigarettes/day or more (0.20, 95% CI; 0.04-0.91) relative to nonsmokers. The OR for passive smoking from 7-15 years of age as a result of the father's smoking habit (0.38, 95% CI; 0.17-0.86) was also significantly low. Smoking was suggested to increase the level of total and antigen-specific IgE in serum by former studies, so that sensitization and symptoms should be studied separately. The high OR of residents in a business or light industrial area (5.00, 95% CI; 1.45-17.3) suggested an association with air pollution.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Respiratory epithelium exposed to sulfur dioxide--functional and ultrastructural alterations.

The value of morphological investigations of airway mucosa should be compared to a functional method when estimating the toxicity of airborne pollutants. In 34 guinea pig tracheas, mucociliary activity was measured using a modified light beam reflex method before and following exposure to sulfur dioxide for 30 minutes in concentrations ranging between 7.5 and 37.5 mg/m3. Exposure to air served as a control. Simultaneously, specimens were taken for light and electron microscopy. Mucociliary activity decreased from 8.4 +/- 2.9 Hz (control exposure) to 4.0 +/- 2.9 Hz following exposure to 7.5 mg/m3, to 3.4 +/- 2.7 Hz at 15 mg/m3 sulfur dioxide, to 1.8 +/- 2.2 Hz at 22.5 mg/m3 sulfur dioxide, to 1.5 +/- 1.8 Hz at 30 mg/m3 sulfur dioxide, and to 2.0 +/- 1.2 Hz at 37.5 mg/m3 sulfur dioxide, respectively (P < .01). Despite a 56% decrease in mucociliary activity, only minor morphological alterations were observed following exposure to 7.5 mg/m3 sulfur dioxide. However, following exposure to 15 mg/m3 sulfur dioxide or higher, structural alterations of respiratory mucosa such as epithelial sloughing, intracellular edema and mitochondrial swelling, widened intercellular space, and ciliary cytoplasmic extrusions were found. Thus measurement of mucociliary activity proved to be a more sensitive indicator of airway toxicity than structural investigations alone.

Animals↗
PubMed2005

Associations between health effects and particulate matter and black carbon in subjects with respiratory disease.

We measured fractional exhaled nitric oxide (FE(NO)), spirometry, blood pressure, oxygen saturation of the blood (SaO2), and pulse rate in 16 older subjects with asthma or chronic obstructive pulmonary disease (COPD) in Seattle, Washington. Data were collected daily for 12 days. We simultaneously collected PM10 and PM2.5 (particulate matter < or = 10 microm or < or = 2.5 microm, respectively) filter samples at a central outdoor site, as well as outside and inside the subjects' homes. Personal PM10 filter samples were also collected. All filters were analyzed for mass and light absorbance. We analyzed within-subject associations between health outcomes and air pollution metrics using a linear mixed-effects model with random intercept, controlling for age, ambient relative humidity, and ambient temperature. For the 7 subjects with asthma, a 10 microg/m3 increase in 24-hr average outdoor PM10 and PM2.5 was associated with a 5.9 [95% confidence interval (CI), 2.9-8.9] and 4.2 ppb (95% CI, 1.3-7.1) increase in FE(NO), respectively. A 1 microg/m3 increase in outdoor, indoor, and personal black carbon (BC) was associated with increases in FE(NO) of 2.3 ppb (95% CI, 1.1-3.6), 4.0 ppb (95% CI, 2.0-5.9), and 1.2 ppb (95% CI, 0.2-2.2), respectively. No significant association was found between PM or BC measures and changes in spirometry, blood pressure, pulse rate, or SaO2 in these subjects. Results from this study indicate that FE(NO) may be a more sensitive marker of PM exposure than traditional health outcomes and that particle-associated BC is useful for examining associations between primary combustion constituents of PM and health outcomes.

Age Factors↗
PubMed1983

[Exposure to anesthetic gases: risk and prevention].

Several studies published during the last fifteen years seem to demonstrate that major risks, i.e. congenital malformations in the offspring and increased rate of spontaneous abortions, are associated with occupational exposure to anesthetic gases (halothane and nitrous oxide) in operating rooms. In view of the severity of the potential risk, we have: 1) analyzed risk factors in the light of epidermiologic and experimental studies; 2) determined the threshold levels of air pollution for these risk factors; 3) analyzed the situation in the Grenoble Hospital and the means of dealing with it.

Abnormalities, Drug-Induced↗