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PubMedDate not supplied

[Study of petroleum-degrading activity of microflora from the shoreline region of the Caspian Sea].

Soil samples from the shore of Baku Bay (Caspian Sea), were studied. The content of oil products in the samples amounted to 2.7-8.0 wt%. The total counts of microorganisms were 1.8 x 10(6) cells per g soil, which is by two orders of magnitude lower compared to soils free from oil pollution. In addition, the diversity of microflora is considerably narrower. The samples were used to isolate pure cultures of microbial degraders capable of assimilating 24 to 32% of the oil introduced into liquid nutrient medium in six days. It was demonstrated that the fraction composition of residual oil changed and both light and heavy oil fractions were degraded.

Biodegradation, Environmental↗
PubMed2000

Using the example of Istanbul to outline general aspects of protecting reservoirs, rivers and lakes used for drinking water abstraction.

The six main drinking water reservoirs of Istanbul are under the threat of pollution due to rapid population increase, unplanned urbanisation and insufficient infrastructure. In contrast to the present land use profile, the environmental evaluation of the catchment areas reveals that point sources of pollutants, especially of domestic origin, dominate over those from diffuse sources. The water quality studies also support these findings, emphasising that if no substantial precautions are taken, there will be no possibility of obtaining drinking water from them. In this paper, under the light of the present status of the reservoirs, possible and probable short- and long-term protective measures are outlined for reducing the impact of point sources. Immediate precautions mostly depend on reducing the pollution arising from the existing settlements. Long-term measures mainly emphasise the preparation of new land use plans taking into consideration the protection of unoccupied lands. Recommendations on protection and control of the reservoirs are stated.

Developing Countries↗
PubMed1991

Inflammatory cell response in bronchoalveolar lavage fluid after nitrogen dioxide exposure of healthy subjects: a dose-response study.

The combination of environmental chamber exposure and bronchoalveolar lavage (BAL) was used to study the effects of the common air pollutant nitrogen dioxide (NO2). Eighteen healthy nonsmokers were exposed to NO2 during 20 min in an exposure chamber during light bicycle ergometer work. All subjects were examined with BAL at least 3 wks before exposure, as a reference. The subjects were re-examined with BAL, in groups of eight, 24 h after exposure to 4, 7 and 10 mg NO2.m.3 (2.25, 4.0 and 5.5 ppm), respectively. An inflammatory cell response was found after exposure to all concentrations. An increase in the number of lymphocytes in BAL fluid was observed after 7 and 10 mg.m.3 (p less than 0.05 and 0.02, respectively). An increase in the number of mast cells, that appears to be dose-dependent, was found after exposure to all concentrations. The proportion of lysozyme positive alveolar macrophages was elevated after exposure to 7 mg.m.3. The inflammatory mediators fibronectin, hyaluronan, angiotensin converting enzyme (ACE) and beta 2-microglobulin were unchanged by exposure. Due to the findings of inflammatory cell changes far below the peak exposure limits for work places in industrialized countries, 9-18 mg.m.3, the safety of these limits is questioned. Studies are in progress in our laboratory using BAL to evaluate the effects of repeated NO2 exposure.

Adult↗
PubMed1993

[Viral epizootic in the marine seal calf (Phoca vitulina) in 1988. Epidemiological aspects].

During the year 1988, an epizootic spread through European populations of harbour seals (Phoca vitulina). The first studies shed light on the importance of a new morbillivirus, close to canine distemper virus but different. However, other factors, like pollution by polychlorinated biphenyl (PCB) compounds may have played a part in the epizootic by increasing mortality. Up to then virology and pathology of wild populations of seals were not well known. This epizootic was an opportunity to learn about seal virus and their specificity, and to discover some biological and evolutionary implications of such a phenomenon.

Animals↗
PubMed1985

Metabolic Basis for Injury to Plants from Combinations of O(3) and SO(2): Studies with Modifiers of Pollutant Toxicity.

Pisum sativum L. cv Alsweet (garden pea) and Lycopersicon esculentum Mill. flacca (mutant tomato) were chosen to evaluate the metabolic basis for plant injury from combinations of O(3) + SO(2). The plants were exposed under conditions reported to specifically alter O(3) or SO(2) toxicity; light versus dark exposures, and treatment with the fungal metabolite fusicoccin (FC), the O(3) injury inhibitor N-[2-(2-oxo-1-imidazolidiny) ethyl]-N'-phenylurea (EDU), and the SO(2) injury stimulator diethyldithiocarbamate (DDTC). Plants were grown in controlled environment chambers and exposed to combinations of O(3) (0.05-0.2 microliters per liter) and SO(2) (0.1-0.3 microliters per liter) for 2 hours. Peas treated with FC had the same or greater injury (quantified by visual rating) with O(3) + SO(2) exposures compared to plants not treated with FC. For plants with open stomata in the dark as well as light, i.e. FC-treated peas and tomatoes, there was no change or an increase in foliar necrosis with O(3) + SO(2) exposures in the dark versus light. Peas treated with EDU had an almost complete absence of O(3) injury, no change in SO(2) injury, and moderate decreases in injury from combinations of O(3) + SO(2) compared to plants not treated with EDU. Tomatoes treated with DDTC showed the same or less injury compared to plants not treated with DDTC and exposed to O(3) or SO(2). The plant responses to the experimental treatments and O(3) + SO(2) resembled O(3) responses more than SO(2) responses. The evidence for O(3)-like responses are: no change or increase in injury in the light versus dark, and EDU-induced decreases in injury. Evidences for SO(2)-like responses are: incomplete protection from injury with EDU, and no change or increased injury to FC-treated versus untreated plants. Thus, a metabolic mechanism affected by both pollutants may be associated with the combination injury, e.g. effects the plasma membrane.

Journal Article↗
PubMed2005

A case study on fuel oil contamination in a mangrove swamp in Hong Kong.

Mangroves commonly found along tropical and subtropical coastlines are susceptible to oil pollution. In December 2000, around 500 1 m tall Kandelia candel saplings at the age of 3-5 years old located at the foreshore region of Sheung Pak Nai swamp, Hong Kong SAR, were found to be damaged by oil pollution. More than 80% of the saplings were either dead or washed away and leaving less than 5% healthy saplings with dense green leaves. Elevated concentrations of light n-alkanes (ranging from n-C14 to n-C20), pristane and phytane were recorded in surface sediments collected in December 2000. The ratio between light and total n-alkanes was 0.4. The total petroleum hydrocarbons (60-80 microg g(-1) TPH) and unresolved complex mixtures (60-70 microg g(-1) UCM) were higher than the background values of other mangrove sediments in Hong Kong, which were 40 and 20 microg g(-1), respectively. In certain root zone sediments, TPH concentrations were above 1000 microg g(-1). These results suggest that surface sediments in Sheung Pak Nai were contaminated by petroleum oil, most likely by illegal discharge of fuel oil which occurred between 1998 and 2002. One year later, in December 2001, unhealthy saplings had recovered and re-grown. The concentrations of TPH and UCM in sediments declined to around 40 microg g(-1), pristane and phytane dropped by 80%, and the ratio of light to total n-alkanes was 0.15, suggesting that residual oil in sediments was weathered leading to a remarkable recovery of the unhealthy saplings.

Alkenes↗
PubMed2004

Modeling of gas-phase photodegradation of chloroform and carbon tetrachloride.

The relationship between the irradiance in a photoreactor and the rate of photodegradation of organics is essential in the scaling-up of photoreactors to treat large volumes of air contaminated with organic pollutants. In this study, the analysis is adopted to compare results obtained from two different photoreactors. Initially, the applicability of two light models in calculating the irradiance in two photoreactors was evaluated. Thereafter, kinetic models of ultraviolet (UV) photooxidation of chloroform (CHCl3) and carbon tetrachloride (CCl4) from the archived literature were tested using experimental data under various operating conditions and different irradiances. Sensitivity analyses were conducted using different values of model parameters to determine the significance of each parameter on the photodegradation of the two chlorinated organics. For compounds that undergo photolysis as a primary mode of degradation, the rate of photodegradation at low initial concentrations can be predicted easily by the following equation: d[C]/dt = -2.303Iave, lambdaepsilonlambdaphilambda[C]. Although the photodegradation of chlorinated organic compounds in dry and humid air can be predicted well, it is difficult to predict the Cl* sensitized oxidation occurring at high initial concentrations. A good agreement between the simulated and experimental data provides a sound basis for the design of large-scale reactors.

Air Pollution↗
PubMed2025

Effects of aerosol aging on composition and light-absorbance of nitrogen-containing organic compounds: Evidences from ultra-high-resolution mass spectrometry analysis.

Nitrogen-containing organic compounds (NOCs) are key components of particulate matter (PM), but their compositional evolution and light-absorbing properties during atmospheric aging remain poorly understood. In this study, ultra-high-performance liquid chromatography coupled with Orbitrap mass spectrometry was used to semi-quantitatively analyze 59 PM1 samples collected in Shanghai. NOCs accounted for 31 % and 64 % of the detected species in negative (ESI-) and positive (ESI+) ionization modes, respectively. Atmospheric aging significantly reduced the molecular diversity of polar organics, with both the number and mass concentration percentages of CHON- compounds showing significant negative correlations with aging degree. Van Krevelen analysis demonstrated a decrease in the number of carboxylic-rich alicyclic molecules and their CHON- contributions during the aging process (from 37.7 % in fresh samples to 21.2 % in aged samples). CHN+ compounds, a major NOCs group in ESI+ mode, also decreased with aging. Correlation analyses involving the Bep/(Bep+Bap) ratio, relative humidity, and mass absorption efficiency at 365 nm revealed a decline in light absorption capacity with aging, suggesting aqueous-phase oxidation as a dominant aging mechanism. CHON- and CHN+ compounds were identified as the principal light-absorbing constituents in PM1. This work provides new insights into the aging-induced transformations of NOCs in urban PM1, and their changing role in light absorption, highlighting the need for further investigation of the aging mechanisms of NOCs.

Aerosols↗
PubMed2003

Analysis of a summertime PM2.5 and haze episode in the mid-Atlantic region.

Observations of the mass and chemical composition of particles less than 2.5 microm in aerodynamic diameter (PM2.5), light extinction, and meteorology in the urban Baltimore-Washington corridor during July 1999 and July 2000 are presented and analyzed to study summertime haze formation in the mid-Atlantic region. The mass fraction of ammoniated sulfate (SO4(2-)) and carbonaceous material in PM2.5 were each approximately 50% for cleaner air (PM2.5< 10 microg/m3) but changed to approximately 60% and approximately 20%, respectively, for more polluted air (PM2.5>30 microg/m3). This signifies the role of SO4(2-) in haze formation. Comparisons of data from this study with the Interagency Monitoring of Protected Visual Environments network suggest that SO4(2-) is more regional than carbonaceous material and originates in part from upwind source regions. The light extinction coefficient is well correlated to PM2.5 mass plus water associated with inorganic salt, leading to a mass extinction efficiency of 7.6 +/- 1.7 m2/g for hydrated aerosol. The most serious haze episode occurring between July 15 and 19, 1999, was characterized by westerly transport and recirculation slowing removal of pollutants. At the peak of this episode, 1-hr PM2.5 concentration reached approximately 45 microg/m3, visual range dropped to approximately 5 km, and aerosol water likely contributed to approximately 40% of the light extinction coefficient.

Air Movements↗
PubMed2003

Lead in grain size fractions of road-deposited sediment.

Road-deposited sediment (RDS) is an important environmental medium for assessing contaminant levels in urban systems. Their atmospheric resuspension has significant implications for human health, and storm water transport can directly impact aquatic biota. Data from 20 RDS samples from Palolo Valley, Oahu, Hawaii, were fractionated into six grain-size classes and analyzed for Pb using a weak HCl (0.5 M) digestion. Data indicate significant Pb contamination in all samples. Median labile Pb concentration (n = 120) was 170 mg/kg, with a range from 4 to 1750 mg/kg. The five sediment fractions < 1000 microm had statistically similar Pb concentrations, but all were significantly greater than the coarsest fraction examined (1000-2000 microm). Silt plus clay ( < 63 microm) was the single most important mass component with 38% of the total sediment stored in this fraction. Mass of sediment < 63 microm combined with a median labile Pb concentration of 222 mg/kg accounted for 51% of the total Pb load stored in road sediments. These findings are significant from an environmental management perspective, and these issues are discussed in light of street sweeper sediment grain size removal efficiencies.

Environmental Pollutants↗
PubMed2001

Removal and decomposition of malodorants by using titanium dioxide photocatalyst supported on fiber activated carbon.

Effective and compact deodorization systems have been required for the measure of small-scale emission sources of offensive odors usually found in urban areas. We have developed a sheet material with titanium dioxide (TiO2) photocatalyst supported on fiber activated carbon (FAC) for a compact deodorization system. In the deodorization system using the TiO2/FAC sheet and a ultraviolet lamp, malodorants can be collected on the TiO2/FAC sheet by adsorption and then decomposed by photocatalysis with UV-irradiation. In this study, we obtained basic information about the removal and the decomposition of malodorants in the photocatalytic deodorization system using the TiO2/FAC sheet. The malodorants used in this study were methyl mercaptan, ammonia, and hydrogen sulfide. In addition, two kinds of light sources, a black light bulb (BLB; dominant wavelength: 365 nm) and an ultraviolet germicidal lamp (UV2; dominant wavelength: 254 nm) were used to analyze the effect on removal and decomposition characteristics by different dominant wavelengths. The removal rates of malodorants from the gas phase were determined in the deodorization system in the presence or absence of the TiO2/FAC sheet and UV-irradiation in order to study each removal effect due to adsorption onto the TiO2/FAC sheet, direct photolysis by UV-irradiation, and photocatalytic decomposition. The effect of adsorption onto the TiO2 /FAC sheet was pronounced in this batch-type experiment. The effect of photocatalysis was observed from the removal rates of methyl mercaptan. The percent oxidation of ammonia to nitrate and that of methyl mercaptan to sulfate were examined by determining products, i.e. nitrate and sulfate ions, with purified water after the reaction. The formation of nitrate or sulfate was not observed without UV-irradiation using the BLB, while the reactions progressed in the presence of the TiO2/FAC sheet. When the UV2 lamp was used, the oxidation of methyl mercaptan to sulfate occurred without the TiO2/FAC sheet. This suggests that the decomposition characteristics of malodorants were dependent on the wavelength of the light source.

Air Pollutants↗
PubMed1989

[The possibilities and limits for virus inactivation in the household].

Viruses of importance brought into the household or excreted by its members vary in their resistance and are decimated or even completely inactivated by natural environmental influences as well as by washing and cleaning. Steps to disinfect the household should be limited to specific indications and performed with virucidal compounds harmless to the environment. Naturally antiviral influences such as heat, UV-rays, sunshine, acids, the effectiveness of washing and cleaning procedures in the household and some selected strongly virucidal, but non-pollutant disinfectants are discussed.

Disinfection↗
PubMed2002

Investigation into the importance of the stomatal pathway in the exchange of PCBs between air and plants.

The transfer of persistent organic pollutants (POPs) from air to vegetation is an important air-surface exchange process that affects global cycling and can result in human and wildlife exposure via the terrestrial food chain. To improve understanding of this process, the role of stomata in uptake of gas-phase polychlorinated biphenyls (PCBs) was investigated using Hemerocallis x hybrida "Black Eyed Stella", a plant with a high stomatal density. Uptake of PCBs was monitored over a 72-h period in the presence and absence of light. Uptake rates were significantly greater in illuminated (stomata open) plants than unilluminated (stomata closed) plants for 18 of the 28 measured PCB congeners (p < 0.05). Depuration of PCBs was monitored in a subsequent experiment over a period of 3 weeks. Levels after 3 weeks of depuration time were still much higher than the concentration prior to contamination. Tri- and tetrachlorinated PCBs showed the greatest depuration, with less than 20% and 50% of accumulated PCBs respectively remaining, while approximately 70% of higher chlorinated PCB congeners remained in the plants at the end of the experiment. Treatments with/without light (to control stomatal opening during uptake) and with/without abscisic acid (ABA) application (to control stomatal opening during depuration) were compared. After contamination indoors for 3 days, there was a significantly higher concentration of PCBs (p < 0.05) in the light contaminated plants than the dark-contaminated plants for 13 of the 28 measured PCB congeners. The ABA treatment affected depuration of PCB-18 only. "Light/ABA-treated" plants had a significantly slower depuration rate for PCB-18 than "light/untreated", "dark/ABA-treated", and "dark/untreated" plants (p < 0.05). The results of the study indicate that there is a stomatal effect on the rate of exchange of PCBs between Hemerocallis leaves and air.

Environmental Monitoring↗
PubMed2006

Air quality biomonitoring: assessment of air pollution genotoxicity in the Province of Novara (North Italy) by using Trifolium repens L. and molecular markers.

Mixed air pollutants are considered a major cause of DNA damage in living species. In this study Trifolium repens L. cv Regal was used as a bioindicator to assess the genotoxicity of air stressors in the Italian province of Novara. Two on-site biomonitoring experiments were performed during the spring and autumn of 2004. Test plants were exposed at 19 monitoring sites distributed homogeneously throughout the province, and each experiment lasted for a period of 6 weeks. Genotoxicity was evaluated with Amplified Fragment Length Polymorphism (AFLP) molecular markers. The results show the predominantly rural central-west region of the Novara Province to have the worst air quality with regard to genotoxicity. Analyses of geomorphology, land use and climatic factors suggest that the compromised air quality in the region could be attributed to wind strength and direction, transporting pollution from vehicular traffic on the A4 highway and from the urban/industrialized centres of Novara and Vercelli. Plant growth, changes in plant photochemical efficiency and the presence of ozone related leaf injuries were also measured to better interpret the results of genotoxicity. Statistical analyses show that although climatic factors such as light intensity and temperature influence plant growth, they do not contribute to atmospheric stressor-induced DNA damage. Further analyses indicated that, as expected, a mixture of genotoxic and non-genotoxic pollutants coexist in the Novara Province troposphere, and that the elevated ozone concentrations experienced during the study may have contributed to the DNA damage in the tested plants by enhancing genotoxicity via interaction with other air stressors.

Air Pollutants↗