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PubMed2002

Formation and identification of intermediates in the visible-light-assisted photodegradation of sulforhodamine-B dye in aqueous TiO2 dispersion.

The photodegradation of dye pollutants under visible light irradiation in TiO2 dispersions continues to draw considerable attention because of the greater effective utilization of solar energy and its potential application in treating wastewaters from textile and photographic industries. To get a better handle on the mechanistics details of this TiO2-assisted photodegradation of dyes with visible radiation, the process was examined by UV-visible spectroscopy, high-performance liquid chromatography, silica gel thin-layer chromatography, and matrix-assisted laser desorption ionization time-of-flight mass spectrometric techniques to separate and identify the N-de-ethylated intermediate products during the photodegradation of N,N,N,N-tetraethylsulforhodamine-B (SRB) in the absence and presence of iodide ions. Five intermediates, namely, N,N-diethyl-N'-ethyl-sulforhodamine, N,N-diethylsulforhodamine, N-ethyl-N'-ethylsulforhodamine, N-ethylsulforhodamine, and sulforhodamine were thus identified. They correspond to intermediate products having a different number of N-ethyl groups, which are removed sequentially from the SRB molecule. The reaction process was accompanied by the oxidation of I- to I3- in the presence of I- ions. Formation of radicals was assessed by spin-trap electron spin resonance spectrometry. The experimental results provided the basis for a more detailed description of the reaction mechanism(s).

Coloring Agents↗
PubMed2002

Environmental remediation by an integrated microwave/UV illumination technique. 3. A microwave-powered plasma light source and photoreactor to degrade pollutants in aqueous dispersions of TiO2 illuminated by the emitted UV/visible radiation.

The characteristic features of a novel double-quartz cylindrical plasma photoreactor (DQCPP) were assessed by examining the photodegradation of rhodamine-B dye (RhB+) in aqueous TiO2 dispersions irradiated simultaneously by both microwave radiation and UV/visible radiation emitted from a microwave-powered (MW, 2.45 GHz) electrodeless mercury lamp. The features of the DQCPP lamp are given and discussed in terms of the experimental output UV energy in the wavelength ranges 210-300 and 310-400 nm for applied MW powers from 74 to 621 W. The DQCPP and a water-cooled DQCPP reactor absorbed more than 50% MW radiation (50-88 and 50-75%, respectively). The emitted light irradiance scaled sublinearly with applied MW power. Relative to the DQCPP lamp, loss of irradiance by the water-cooled DQCPP lamp was approximately 28-46% at 250 nm and approximately 41-58% at 360 nm in the range of MW power used. The smallest loss occurred at 178.9 W at which the degradation of RhB+ was subsequently examined by UV/visible spectroscopy and by total organic carbon analyses. Highly intense mercury lines were seen at 365, 404, 435, 546, and 579 nm (those below 365 nm were more than 10 times weaker). About 80% of the RhB+ solution was photomineralized after 60 min of irradiation of the aqueous RhB+/TiO2 dispersion with the DQCPP lamp; no UV/ visible spectral features of RhB+ were evident at wavelengths below 250 nm after 30 min. Possible effects of microwave radiation and temperature on the degradative process are described.

Coloring Agents↗
PubMed2003

Solar activated ozonation of phenol and malic acid.

The effect that sunlight has on the degradation rate of two model organic compounds, phenol and malic acid, by ozone is studied. The effect seems to be due to both direct light absorption (300-320 nm photons) by ozone, which produces the pollutant degradation, and light absorption by reaction intermediates. The presence of such a light notably improves the reactivity of ozone toward the organic species, leading to a faster and complete mineralization even at large initial total organic carbon values. The use of artificial sunlight (Xe lamp) is also explored. Finally, the simultaneous presence of sunlight and other ozone degradation catalyst like transition metal ions is studied, showing the beneficial effect of such a combination.

Absorption↗
PubMed1984

Environmental pollutant Cd2+ biphasically and differentially regulates myosin light chain kinase and phospholipid/Ca2+-dependent protein kinase.

Cd2+ was found to mimic effectively, potentiate and antagonize the stimulatory action of Ca2+ on myosin light chain kinase (MLCK) and phospholipid-sensitive Ca2+-dependent protein kinase (PL-Ca-PK, or protein kinase C). PL-Ca-PK, however, was slightly less sensitive to Cd2+ regulation than was MLCK. Cd2+ also biphasically regulates (i.e., stimulation followed by inhibition) phosphorylation, in the homogenates of the rat caudal artery, of myosin light chain and other endogenous proteins catalyzed by MLCK and PL-Ca-PK. The activation by Cd2+ of MLCK was inhibited by anticalmodulins (e.g., R-24571), whereas the inhibition by a higher Cd2+ concentration of MLCK and PL-Ca-PK was reversed by thiol agents (e.g., cysteine). The present findings may provide one mechanism underlying the vascular toxicity of Cd2+, a major environmental pollutant.

Animals↗
PubMed1991

[Effect of air pollution in MTTp (convenient calculation) of children].

A convenient formula (MTTp = 0.1FVC/2Vp) was derived according to the linear character of each 10% FVC portion on the FVC-t curve proposed by Jordanoglou. It was used to examine 765 healthy school children at the age of 8-13 in the lightly and heavily polluted, and controlled areas in the living quarters in a steel corporation. The results showed that the small airways were more severely affected than the larger ones. MTT45-55% at the middle lung volume had both higher sensitivity and accuracy, and could be considered as a good index for tests on the function of small airways in air pollution while MTT20-30% and MTT70-80% at high and low lung volumes had greater variability and less accuracy.

Air Pollutants↗
PubMed2005

Degradation of dye pollutants by immobilized polyoxometalate with H2O2 under visible-light irradiation.

A Keggin polyoxometalate (POM, i.e., PW12O40(3-)) and its lacunary derivative are immobilized on an anionic exchange resin through electrostatic interaction at pH 4.6 in an aqueous dispersion. The resin-supported POM thus obtained catalyzes the efficient degradation of cationic dye pollutants in the presence of H2O2 under visible-light irradiation. To evaluate the photocatalytic system, degradation of a rhodamine B (RB) dye was investigated in detail using UV-visible spectroscopy, high performance liquid chromatography, and gas chromatography/mass spectrometry techniques to identify the intermediates and final products. Fluorescence lifetime measurements revealed the electron transfer from the visible-light-excited RB molecules to the POMs. Electron paramagnetic resonance measurements, investigation of the effects of *OH and *OOH scavengers on the photoreaction kinetics, and IR analysis indicated that de-ethylation of RB was due to *OOH radicals, but the decomposition of the conjugated xanthene structure was caused by the peroxo species formed by interaction of H2O2 with the lacunary POM loaded on the resin. A total organic carbon removal of ca. 22% was achieved, and the recycle experiment suggested excellent stability and reusability of the heterogeneous catalyst. On the basis of the experimental results, a photocatalytic mechanism is discussed.

Catalysis↗
PubMed2000

The interaction "light, Fe(III)" as a tool for pollutant removal in aqueous solution: degradation of alcohol ethoxylates.

The photoinduced degradation of an alcohol ethoxylate (AE) (Brij 30) by Fe(III) in aqueous solution has been investigated. The study was carried out with the major fraction of ethoxymers having an alkyl chain length of 12 carbon atoms and n ethoxy units E (C12En). The Fe(III) sensitised degradation of this fraction occurs efficiently at 365 nm. The rate of degradation depends on the concentration of Fe(OH)2+, the most photoreactive species in terms of .OH radical formation. Formate ethoxylates were identified as photoproducts and shortening of the ethoxylated chain all along the degradation process was observed. The mechanism of Brij 30 degradation implies a major .OH radicals attack on the polyethoxylated chain. For prolonged irradiations, the total degradation of Brij 30 and of the photoproducts is obtained. Consequently, the degradation photoinduced by iron (III) could be an efficient method of AEs removal in water.

Detergents↗
PubMed1976

Immunoglobulins under the influence of nonspecific factors. III. Immunoglobulins, pertussis antibodies and lysozyme in three child populations exposed to different air pollution.

The levels of IgG, IgA, IgM, lysozyme, agglutinins against B. pertussis and B. parapertussis were followed in the blood serum of 306 children 9--10 years old in 3 areas of Central Bohemian region. In children dwelling in areas with more polluted air significantly higher levels of serum lysozyme and of parapertussis antibodies were found by the t-test. The distribution of these values shows significant differences between more polluted areas in comparison with lower-pollution area also in Kolmogorov-Smirnov test. The average levels of Ig approached statistically critical values but did not reach them, but significant differences in the distribution of values of IgG and IgA were shown by the F-test and chi2-test between lightly and heavily polluted areas. The values of immunological reactions in polluted areas were always higher than in the non-polluted group. This provides evidence for a hypothesis about a stimulatory effect of polluted air on immunological mechanisms in child population. The higher values of IgM observed recently by other authors in women were shown in girls of 9--10 years.

Agglutinins↗
PubMed2001

Monitoring of 1-min personal particulate matter exposures in relation to voice-recorded time-activity data.

Recent studies on the association between exposures to airborne particulate matter (PM) and disease have identified short-term peaks in PM exposures as posing especial health threats. Lightweight personal instruments are needed to characterize short-term exposures to PM and to identify the most important sources of high PM excursions. In this study, we measured exposure to fine PM using a small personal nephelometer (pDR; MIE, Inc) to investigate the utility of this instrument in identifying activities and microenvironments most associated with high PM exposures and the magnitude and duration of peaks in PM exposures. Ten adult volunteers wore a pDR recording PM concentrations at 1-min time intervals for 1 week each. PM concentrations were measured by the pDR in units of microg/m(3) based on light scatter. The use of a time-stamped voice recorder enabled activity and location to be continuously documented in real time. In addition, a small, inexpensive light intensity logger was affixed to the pDR to evaluate the potential of this instrument to assist in verifying wearer- recorded data. For each person, patterns of PM exposure were remarkably consistent over daily activities and showed large excursions associated with specific indoor and outdoor microenvironments and activities, such as cooking. When the magnitude and duration of excursions in PM were analyzed, we found that high PM levels occurred in relatively few of the minutes measured but comprised a substantial fraction of the total exposure to PM. Fifteen-minute averaged PM levels were found to be as much as 10 times the daily average. When the data were analyzed with a generalized estimating equation model to account for effects of autocorrelation and clustering, PM exposure was significantly higher during subject-reported events including barbeque, yard work, being near pets or construction activities, cooking, and environmental tobacco smoke exposure, as compared with periods with no pollution events. When light intensity data were explored to determine whether these loggers could be of potential use in establishing or verifying indoor vs outdoor location for future PM studies, we found that personal light intensity measurements differed among indoor, outdoor, and in-car environments (P<0.001). Overlap between measured values implies that light intensity cannot be used to absolutely predict location; however, a sudden increase or decrease in light intensity was highly associated with participant report of location change between indoors and outdoors. This study demonstrates the utility of the pDR in identifying patterns of personal exposures to particulate matter and especially in registering the magnitude and duration of excursions in PM in relation to location and activity.

Activities of Daily Living↗
PubMed1976

Morphometric study of trout gills: a light-microscopic method suitable for the evaluation of pollutant action.

1. Methods are described for the morphometric estimation of parameters of the gill system of trout which are relevant to its function in gas exchange. The methods have been used with 1 mum sections viewed under the light microscope. 2. In particular the diffusion distances between water and blood are measured, which together with determinations of gill area, provide figures for the morphometrically estimated diffusing capacity. 3. The methods have been used to compare the diffusing capacity of gills from control fish and those treated in polluted waters. The concept of relative diffusing capacity (Drel) is introduced which enables comparisons to be made without the need to determine the absolute diffusing capacity. 4. Quantitative estimation of changes in relative volumes and surface areas of components of the secondary lamellae were determined, and employed to explain the possible anatomical causes of changes in Drel. 5. It is suggested that these methods can be of value in the comparison of the gills of fish treated in different waters.

Animals↗
PubMed2006

Modelling atmospheric pollution during the games of the XXVIII Olympiad: effects on elite competitors.

UNLABELLED: The present study investigated the specific atmospheric conditions expected in Athens during the summer of 2004 in relation to the performance of elite athletes. DESIGN: Atmospheric pollution and weather data for the period April 16th to September 30th covering the entire greater Athens area and collected from 1984 to 2003 were used for descriptive statistics and model fitting. The analysis was focused on carbon monoxide (CO), ozone (O3), sulfur dioxide (SO2), nitrogen oxide (NO), nitrogen dioxide (NO2), and particulate matter with a diameter of < 10 microm (PM10). Factor and cluster analysis were used to describe atmospheric pollution in the northern, central, and southern sector of Athens. Generalized estimated equations (GEE) analysis was used to predict mean August 2004 pollutant concentration. Increased concentrations of O3 and PM10 (mean 2003 values: 134.3 +/- 9.3, 44 +/- 1.9 microg/m3, respectively) may generate adverse health and performance effects. The highest O3 values were recorded in the northern Athenian sector during the period June 12th to July 23rd, peaking around mid-day (12:00-18:00) (p < 0.05). The highest PM10 concentrations were recorded in the central Athenian sector during the period August 20th to September 9th, peaking at late afternoon (14:00-22:00) (p < 0.05). Similar concentrations were observed during all days of the week (p > 0.05). GEE approximated mean August 2004 pollutant concentrations similar to: CO: 2.8 (mg/m3), O3: 136, SO2: 24, NO: 134, and NO2: 106 (microg/m3). Concentrations of O3 and PM10 during the XXVIII Olympiad may generate adverse health and performance effects on the cardiovascular function of the elite competitors. (The present manuscript was submitted shortly before the start of the Games and became published after their completion. In this light, the actual pollution rates in Athens during August 2004 are presented in the Note Added in Proof as credence to the statistics used).

Air Pollutants↗
PubMed2005

Air pollution and cancer: biomarker studies in human populations.

Large cohort studies in the U.S. and in Europe suggest that air pollution may increase lung cancer risk. Biomarkers can be useful to understand the mechanisms and to characterize high-risk groups. Here we describe biomarkers of exposure, in particular DNA adducts as well as markers of early damage, including mutagenicity, other endpoints of genotoxicity and molecular biomarkers of cancer. Several studies found an association between external measures of exposure to air pollution and increased levels of DNA adducts, with an apparent levelling-off of the dose-response relationship. Also, numerous experimental studies in vitro and in vivo have provided unambiguous evidence for genotoxicity of air pollution. In addition, due to the organic extracts of particulate matter [especially various polycyclic aromatic hydrocarbon (PAH) compounds], particulate air pollution induces oxidative damage to DNA. The experimental work, combined with the data on frequent oxidative DNA damage in lymphocytes in people exposed to urban air pollution, suggests 8-oxo-dG as one of the important promutagenic lesions. Lung cancer develops through a series of progressive pathological changes occurring in the respiratory epithelium. Molecular alterations such as loss of heterozygosity, gene mutations and aberrant gene promoter methylation have emerged as potentially promising molecular biomarkers of lung carcinogenesis. Data from such studies relevant for emissions rich in PAHs are also summarized, although the exposure circumstances are not directly relevant to outdoor air pollution, in order to shed light on potential mechanisms of air pollution-related carcinogenesis.

Air Pollutants↗
PubMed2005

The next step--incorporating diffuse pollution abatement into watershed management.

The majority of adverse changes in watersheds impairing water quality occurred over a period of thirty to more than one hundred years. In many areas over a period of about 80 years more than 90% of the wetlands were drained, cultivated and converted to agricultural and urban uses. This conversion changed the redox status of the soils and soil cover with a concurrent large increase of suspended solids, dissolved organic matter, nitrogen, and phosphate loads from the watersheds located in the affected regions. The question whether these adverse changes are reversible by reduction or discontinuation of excessive inputs of pollutants came to light and has been analyzed recently after the political changes in Eastern Europe. Reliable dynamic long term models that would describe interactions between nutrient inputs, outputs, storage etc., have not been developed yet. It is becoming apparent that it may take longer for the watersheds to recover after nutrient loads to surface and groundwater are reduced if remedial measures are gradually implemented.

Conservation of Natural Resources↗
PubMed2003

On-line and in situ biosensors for monitoring environmental pollution.

Efficient tools for on-line and in situ monitoring of environmental pollutants are required to provide early warning systems. In addition, such tools can contribute important information on the progress of various remediation treatments. One of the recently developed monitoring technologies involves the use of whole-cell biosensors. Such biosensors could be constructed to detect general toxicity or specific toxicity caused by one or more pollutants. Currently, a large spectrum of microbial biosensors have been developed that enable the monitoring of pollutants by measuring light, fluorescence, color or electric current. Electrochemical monitoring is of special interest for in situ measurements as it can be performed using simple, compact and mobile equipment and is easily adaptable for on-line measurements. Here we survey the potential application of electrochemical biosensors in monitoring of general toxicity as well as hydrocarbons and heavy metals.

Bacteria↗
PubMed2003

Phenanthrene biodegradation by an algal-bacterial consortium in two-phase partitioning bioreactors.

An algal-bacterial consortium formed by Chlorella sorokiniana and a phenanthrene-degrading Pseudomonas migulae strain was able to biodegrade 200-500 mg/l of phenanthrene dissolved in silicone oil or tetradecane under photosynthetic conditions and without any external supply of oxygen. Phenanthrene was only removed when provided in organic solvent, which confirms the potential of two-phase systems for toxicity reduction. Phenanthrene was degraded at highest rates when provided in silicone oil rather than in tetradecane since this solvent probably sequestered the PAH, reducing its mass transfer to the aqueous phase. The influence of phenanthrene concentration, amount of inoculum and light intensity on pollutant removal was also investigated and, under the best conditions, phenanthrene was degraded at 24.2 g m(-3).h(-1). In addition to being cost-effective and mitigating the release of greenhouse gases into the atmosphere, photosynthetic oxygenation was especially beneficial to the use of two-phase partitioning bioreactors since it prevented solvent emulsification and/or volatilization and evidence was found that the microalgae release biosurfactants that could further enhance phenanthrene degradation.

Aerobiosis↗
PubMed2006

Renal and neurologic effects of cadmium, lead, mercury, and arsenic in children: evidence of early effects and multiple interactions at environmental exposure levels.

Lead, cadmium, mercury, and arsenic are common environmental pollutants in industrialized countries, but their combined impact on children's health is little known. We studied their effects on two main targets, the renal and dopaminergic systems, in > 800 children during a cross-sectional European survey. Control and exposed children were recruited from those living around historical nonferrous smelters in France, the Czech Republic, and Poland. Children provided blood and urine samples for the determination of the metals and sensitive renal or neurologic biomarkers. Serum concentrations of creatinine, cystatin C, and beta2-microglobulin were negatively correlated with blood lead levels (PbB), suggesting an early renal hyperfiltration that averaged 7% in the upper quartile of PbB levels (> 55 microg/L; mean, 78.4 microg/L). The urinary excretion of retinol-binding protein, Clara cell protein, and N-acetyl-beta-d-glucosaminidase was associated mainly with cadmium levels in blood or urine and with urinary mercury. All four metals influenced the dopaminergic markers serum prolactin and urinary homovanillic acid, with complex interactions brought to light. Heavy metals polluting the environment can cause subtle effects on children's renal and dopaminergic systems without clear evidence of a threshold, which reinforces the need to control and regulate potential sources of contamination by heavy metals. Key words: arsenic, biomarkers, cadmium, dopaminergic, heavy metals, interactions, lead, mercury, renal.

Arsenic↗