Green care. Lights out.
Explore the source record for details and available documents.
Conservation of Energy Resources↗
SEARCH · Search PubMed
Results for “Light Pollution”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[The influence of chemical factors on the oral cavity in workers of the Szczecin Plant of Phosphorous Fertilizers in the light of our own investigations].
Explore the source record for details and available documents.
Air Pollution↗
Transformations of environmental contaminants by light.
Explore the source record for details and available documents.
DDT↗
Removal of hydrogen sulfide by Chlorobium thiosulfatophilum in immobilized-cell and sulfur-settling free-cell recycle reactors.
Bioconversion of hydrogen sulfide to elementary sulfur by the photosynthetic bacterium Chlorobium thiosulfatophilum was studied in immobilized-cell and sulfur-settling free-cell recycle reactors. The cells immobilized in strontium alginate beads excreted elementary sulfur and accumulated it as crystal in the bead matrices, which made it possible that the reactor broth remained clear and the light penetrated the reactor deeper than with the free cells. In comparison with the free cells, the immobilized cells required 30% less light energy at a H2S removal rate of 2 mM/(L.h) and showed an activity of 2.4 times that of the free cells. However, in 40 h after the reaction the deterioration of the H2S removal efficiency became significant due to the accumulation of sulfur in the beads. The scanning electron micrograph (SEM) and energy-dispersive X-ray spectrometer (EDS) studies showed that the sulfur in the beads existed within a layer of 0.4 mm from the bead surface. In the sulfur-settling free-cell recycle reactor, about 80% of the sulfur excreted by the free cells could be removed in a settler. The 4-L fed batch reactor with the settler improved the light transmission to result in a H2S removal rate of 3 mumol/(mg of protein.h), 50% higher than that without it. The settling recycle reactor was much better in the removal of H2S than the immobilized-cell reactor because the former was a continuous system with the constant removal of sulfur particles by settling and of spent medium by supplying fresh medium at the same rate as the filtering rate of the reactor broth, while the latter was essentially a batch system where toxic metabolites and produced sulfur could not be removed.
Air Pollutants↗
Photochemical characterization of water samples from Minnesota and Vermont sites with malformed frogs: potential influence of photosensitization by singlet molecular oxygen (1O(2)) and free radicals on aquatic toxicity.
Environmental pollutants activated by UV sunlight may have contributed to the recent decline in frog populations and the concomitant increase in malformations in the USA and abroad. UV radiation is able to mutate DNA and to initiate photosensitization processes that generate mutagenic and biologically disruptive oxygen transients. We have examined water from selected sites in Minnesota and Vermont using singlet molecular oxygen (1O(2)), detected by its phosphorescence and free radicals detected by spin trapping, as markers for photosensitization. Water from a pond in Minnesota with malformed frogs, which also causes malformations in the laboratory, photosensitized more 1O(2), even though it absorbed less UV light compared to water from a site that did not cause malformations. This suggested that unknown natural or pollutant agents were present, and that photosensitization may be involved. Although UV irradiation of the two Minnesota water samples in the presence of the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) revealed the presence of the DMPO/*OH, DMPO/*H(e(aq)-) and DMPO/*C(unknown) adducts there were no qualitative or quantitative differences between them. We also examined water samples from several sites in Vermont, and compared them by measuring the quantum yield of 1O(2) photosensitization. While all the Vermont samples produced a small amount of 1O(2), there was no clear correlation with the incidence of frog malformations. However, the samples differed strongly in absorption spectra and the ability to quench 1O(2). These factors may determine how much UV light is absorbed and converted into chemical reactions. Our results show that photochemical characterization of 1O(2) photosensitization is possible in untreated natural water samples. Photosensitization falls into the category of global factors that may be closely associated with the effects of UV irradiation of the Earth's environments. Thus, photosensitization might be an important component in global amphibian malformation and decline. The observation of 1O(2) emission directly from natural water may also provide new opportunities to investigate the involvement of 1O(2) in other complex environmental processes.
Animals↗
Air pollution and lung cancer.
Epidemiological evidence proves conclusively that lung cancer correlates with air pollution. However, data on lung cancer death rates and smoking show that mankind accepts the risk of long-term and low-level exposure to carcinogens. As a rule, immediate benefits are sought and remote hazards ignored. Fear of atmospheric contamination by radioactive fallout seems to be the main factor for awareness of air pollution. Experimental works help us to understand physics of particle deposition in the lungs (inertial impactation, sedimentation, Brownian movement), shed light on carcinogenesis (eg, bay region theory in case of polycyclic aromatic hydrocarbons and surface charge changes regarding asbestos), show that atmospheric particulates accepted as harmless may act as co-carcinogens (eg, iron and benzo(a)pyrene) and stress the importance of in vitro researches (bacterial mutation tests, organ cultures, sister chromatid exchange system) to screen pollutants for their malignant potential and study their pathogenesis.
Aerosols↗
From science to policy--when are scientific results certain enough?
The amount of scientific findings linking air pollution with adverse health effects is continuously growing and indicates a need for action to improve air quality. On 21 September 2005, the European Commission published a new draft directive on air quality, as part of the Thematic Strategy on air pollution. This is a long-term plan on how to reduce air pollution in the European Union in the next 15 years. Immediately after its release, the Commission received criticism for not going far enough from various instances, such as research institutions and nongovernmental organizations concerned with health and environmental effects of air pollution. One policy argument for not taking full measures was the argument of scientific uncertainty. In light of this air quality strategy and the corresponding criticism which ensued, the present article discusses how the ambiguity of scientific uncertainty may contribute to impeding the process of translating scientific findings into concrete policy options. As complete certainty is likely to never be achieved, the question arises whether it is possible to determine and agree on clear and applicable definitions of certain levels of scientific certainty. The case referred to in this paper clearly demonstrates a situation with discordant views on the uncertainty of scientific findings. More discussion on how to define scientific uncertainty and how to deal with it would be beneficial for both the scientific and the political communities. Finally, it is important to recognize that scientific evidence is not the only driver influencing policy decisions.
Air Pollutants↗
Total microbial activity and microbial composition of a mangrove sediment are reduced by oil pollution at a site in the Arabian Gulf.
In a study carried out to determine the effect of oil pollution on the microbiota of sediment associated with mangroves in the United Arab Emirates, sediment samples were collected from oil-polluted and nonpolluted mangrove sites. The levels of the total recoverable hydrocarbons and the polycyclic aromatic hydrocarbons assayed were noticeably higher in the polluted sediment. Microbial activity as measured by the hydrolysis of fluorescein diacetate and by the total populations of the culturable aerobic and anaerobic bacteria, streptomycete and non-streptomycete actinomycetes, and filamentous fungi and yeasts was significantly (P < 0.05) lower in the polluted than in the nonpolluted sediment. The estimated total aerobic and anaerobic hydrocarbon-utilizing bacteria were significantly (P < 0.05) higher in the polluted than in the nonpolluted sediments. Four days after the addition of the water-soluble fractions of the light Arabian crude oil to the nonpolluted sediment, at 10 different concentrations, there was a significant (P < 0.05) reduction (65%) in the microbial activity of the sediment compared with that of nonamended sediment. Concentrations of water-soluble fractions at 0.1% and above significantly and progressively reduced microbial activity, with total cessation of activity recorded at levels >50%. This study is the first to evaluate the effect of oil pollution on aerobic and anaerobic microbial flora of sediment of mangrove communities.
Arabia↗
Radish (Raphanus sativus L.): a model for studying plant responses to air pollutants and other environmental stresses.
The use of Raphanus sativus L. as a model crop for studies on plant response to environmental stresses is reviewed with emphasis on the effects of different atmospheric pollutants (O(3), SO(2), NO(2), acidic precipitation) and their combinations. Responses to temperature, light supply, water stress, and atmospheric CO(2) are also studied and discussed. In addition, the references reviewed are evaluated in terms of their experimental protocols on growth conditions and recommendations for optimal ranges of environmental and cultural variables, i.e. light, temperature, nutrient supply are given. Its distinct pattern of biomass partitioning, the small dimensions along with short and easy culture make radish an excellent experimental plant. The fleshy below-ground storage organ, formed by the hypocotyl and upper radicle, acts as the major sink during vegetative development. Abundant assimilate supply due to elevated levels of CO(2) along with high irradiation frequently promote hypocotyl growth more than shoot growth, whereas under conditions of stress shoot growth is maintained at the expense of the hypocotyl. This makes the hypocotyl: shoot ratio of radish a very sensitive and suitable indicator for various environmental stresses. Potential weaknesses and shortcomings of radish in its role as a model crop, particularly the high variability of injury and growth responses, are discussed along with possible solutions. Future research needs are derived from the summarized results presented and from some disparities among findings within the literature reviewed.
Journal Article↗
Indoor radon/thoron survey report from Hamirpur and Una districts, Himachal Pradesh, India.
A survey of indoor radon and thoron levels has been carried out in a number of villages in the vicinity of uranium bearing sites in the Hamirpur and Una districts of Himachal Pradesh (H.P.), India. Levels were analysed with reference to the nature of building material, soil type and different seasons of the year. The one year average for radon concentration was found to vary from a minimum of 19.7 to a maximum of 146.3 Bq/m3 while the minimum and maximum thoron concentrations were 9.1 and 70.7 Bq/m3, respectively. The dose rate varied from 0.1 to 8.67 microSv/h. These are discussed in the light of ICRP recommendations.
Air Pollutants, Radioactive↗
Biochemistry of the bacterial catabolism of aromatic compounds in anaerobic environments.
Methods of aerobic degradation of aromatic compounds in the biosphere are well understood, but it is only relatively recently that it has been shown how some bacteria can also degrade these substrates in the absence of molecular oxygen. This occurs by photometabolism (Athiorhodaceae), nitrate respiration (Pseudomonas and Moraxella sp.) and methanogenic fermentation (a consortium) in which the benzene nucleus is first reduced and then cleaved by hydrolysis to yield aliphatic acids for cell growth. These methods may be used by microbial communities to catabolise man-made pollutants.
Anaerobiosis↗
Multipass acoustically open photoacoustic detector for trace gas measurements.
What we believe to be a novel multipass, acoustically open photoacoustic detector designed for fast-response, high-sensitivity detection of trace gases and pollutants in the atmosphere is demonstrated. The acoustic pulses generated by the absorption of the light pulses of a tunable optical parametric oscillator by target molecules are detected by an ultrasonic sensor at 40 kHz. The photoacoustic signal is enhanced by an optical multipass arrangement and by concentration of the acoustic energy to the surface of the ultrasonic sensor. The detection sensitivity, estimated from CO2 measurements around a 2 microm wavelength, is approximately 3.3 x 10(-9) W cm(-1).
Journal Article↗
Normal value for the direct micronucleus test on peripheral blood mononuclear cells from healthy donors.
OBJECTIVE: To obtain the normal value of micronuclei in peripheral blood mononuclear cells. STUDY DESIGN: We screened 300 blood samples for micronucleated cells. Samples from donors who smoked, were ill or lived in a polluted area were excluded. From each sample, 500 swollen mononuclear leukocytes were screened with a light microscope, using 400x magnification. A frequency distribution of micronucleated cell number was made, and the mean of micronucleated cell number was calculated. Further, the data were tested for the type of probability distribution using the test of goodness of fit, and the parameters were estimated. RESULTS: Of the 300 samples, 203 were excluded and 97 analyzed. In the 97 samples, the mean of micronucleated cells (from 500 cells screened) was 0.59; the data followed a Poisson distribution. The 95% confidence limits were .45 and .76. CONCLUSION: The normal value in unexposed individuals is .59 micronucleated cells per 500 cells.
Blood Donors↗
[Reef community structure at Falcón, Venezuela, before and after a mass mortality].
Morrocoy National Park used to be considered the most important continental coral reef of Venezuela. However, in January of 1996, there was a massive mortality of the benthic organisms for unknown reasons. The coral reef community was monitored since 1995, the year before the event, and yearly after that, until June 1999, by sampling linear transects and quadrats. A total of 26 hard corals were recorded in the study site (Playa Mero) in 1995 (36.56% cover), which already had some deterioration because 90.86% of the living coral cover was represented basically by four species, M. annularis with 51.36%, Colpophyllia natans with 18.22%, Agaricia agaricites with 11.58% and Porites porites with 9.70%. Three months after the event, living coral cover was only 4.84% and algae, particularly Dyctiota spp. covered most of the surface (81.89%). Benthic organisms suffered massive mortality over the whole depth gradient and in most park reefs. Even after three years the reef community shows highly perturbed conditions, with 85% of the total cover represented by the categories: dead coral, dead coral overgrowth by algae and sand. From the initial coral richness of the area (26 species) only nine species were observed although in very low cover (<1%), except for M. annularis and M. franksi, which presented lightly higher percentages.
Animals↗
Emission testing and inhalational exposure-based risk assessment for candles having Pb metal wick cores.
Segments of seven candles with wicks having a Pb metal core have been tested in a purpose-built combustion chamber to assess air Pb emissions. Emissions were collected on glass fibre filters that have been digested in concentrated HNO3 and analysed by flame atomic absorption spectroscopy (FAAS). Despite an indication of a bimodal distribution in Pb emission rates, and a range from 450 to 1130 micrograms Pb/h, the mean rate from the seven candles was 770 micrograms Pb/h. The 38-cm long candles are, on average, capable of emitting 104,000 micrograms of Pb into the air over approximately 127 h. A mean value of 20% of the Pb metal in the wick consumed by the candle is emitted into the air, the remainder appears to accumulate at the base of a molten wax-pool adjacent to the wick. Individual Pb-bearing particles from the combustion of candles were observed in a field emission scanning electron microscope (FESEM) to have a diameter of 1 micron or less. The emission from the candles has been analysed by X-ray diffraction (XRD) and identified as Sodium Lead Carbonate Hydroxide [NaPb2(CO3)2OH]. This compound, being a Pb carbonate, is likely to be easily absorbed in the lungs and gastrointestinal tract. Risks associated with inhalational exposure have been assessed after determining indoor lead in air (PbA) concentrations. Given a lack of information on the duration of use of candles, a range of scenarios from worst possible case to daily and weekly burning regimes are evaluated. Detailed evaluations of PbA are based on the emission from a single candle at rates of 500 and 1000 micrograms Pb/h, room volumes of 25 and 50 m3, durations of emission of 1.5, 3 and 6 h and air infiltration rates of 0, 0.25, 0.5, 0.75 and 1.0 air volume changes per hour (ACH). A candle burnt for 3 h at 1000 micrograms/h in a 50 m3 room having poor ventilation at 0.25 ACH is estimated to yield a 24-h average lead in air concentration of 9.9 micrograms/m3 with a peak PbA value of 42.1 micrograms/m3. Daily exposure to such candle burning where children spend 80% of their time indoors is likely to elevate PbB in children by a minimum of 24 to 40 micrograms/dl, according to the PbB:PbA relationship of Brunekreef, 1984 (The relationship between air lead and blood lead in children: a critical review). Estimating child Pb uptake from first principles using a range of exposure factors, a child would obtain some 85 to 127% of the provisional tolerable weekly Pb intake (PTWI) from such daily exposure. Child blood lead levels could readily exceed levels of 10 micrograms/dl, largely due to exposure to emissions from burning Pb wick core candles for several hours once per week. The regular burning of multiple candles in small, poorly ventilated spaces could readily be associated with clinical Pb poisonings and death. High levels of exposure could occur with Pb metal core wick candles in less developed countries where candles are used on a daily basis for indoor lighting purposes in small dwellings. Prolonged burning of candles may occur in religious and in ceremonial circumstances or restaurants where they may be of particular concern. On the basis of the limited investigation carried out, candles having a wick with a Pb metal core have the potential to present highly unacceptable and avoidable risks to human health.
Air Pollution, Indoor↗
Short-term respiratory effects of polluted ambient air: a laboratory study of volunteers in a high-oxidant community.
To investigate short-term health effects of community air pollution directly, we developed a mobile laboratory allowing "blind" exposures of volunteers to polluted ambient air and to purified air at similar temperature and humidity. Subjects (30 asthmatic, 34 normal) from the surrounding area were studied at Duarte, California, a Los Angeles suburb subject to frequent photochemical oxidant pollution. Each was exposed to a close approximation of outdoor ambient air for 2 h with intermittent light exercise. Lung function and symptoms were evaluated pre- and post-exposure. A control (purified air) study took place several weeks later. Mean ambient air exposure concentrations were near 0.22 ppm for ozone and 200 micrograms/m3 for total suspended particulate. Ambient air exposures were associated with small significant losses in forced expiratory performance and total lung capacity. The responses of asthmatic and normal subjects were generally not significantly different, possibly because many normal subjects had a history of allergy and appeared atypically reactive to respiratory insults. In the normal subjects, a small significant increase in reported symptoms was seen with ambient air exposures compared with the control. In the asthmatics, the increase was not significant. Over-all, only slight effects attributable to exposure were found, even though a severely polluted area and a presumed high-risk population were chosen for study.
Adolescent↗
Effects of salt concentration on floc characteristics and pollutants removal efficiencies in treatment of seafood wastewater by SBR.
Most seafood wastewater has been treated by the activated sludge process. Due to changes in salt concentration, pollutant loadings and raw materials, the process is not operated satisfactorily to meet effluent regulation. Most problems faced at present are solid liquid separation. In this study, effects of salt concentration on floc characteristics and pollutants removal efficiencies were investigated in treatment of seafood wastewater by SBR. For analyzing fractal dimension of flocs, the small angle laser light scattering (SALLS) method was applied using a Diffraction Particle Sizer (Malvern Instruments). Organic removal efficiencies (in terms of COD(Mn)) decreased with increasing salt concentration, but eventually reached a steady state. Fractal dimension and floc size also showed similar trends with changing salt concentration. The main reasons to reduced pollutant removal efficiencies were deteriorated biological activity and settling properties. The biological activity was affected faster than the floc characteristics by increasing salt concentration. The deteriorated settling properties were explained by decreased size and fractal dimension of floc due to increasing salt concentration. The settling properties of floc such as sludge volume index (SVI) and zone settling velocity (ZSV) were related to size and fractal dimension of floc. The fractal dimension of floc was better related to the settling properties than the size of floc.
Bioreactors↗
Public health response to an incident of secondary chemical contamination at a beach in the United Kingdom.
OBJECTIVES: To gather enough data from a large scale investigation involving two health authorities, to assess the possible concentrations and routes of exposure and the consequent health implications. To use the data to decide whether a polluted beach should remain open to the public. In Spring 1997, a chemical incident came to light at a beach on the south coast of England when a local resident reported a sulphurous smell, visible signs of oil, and reduced numbers of fishing bait. The beach was situated adjacent to a former gasworks site and was accessible to the public. The incident was reported to the local authority and was initially investigated by the Environment Agency and the local authority. An Environment Agency report confirmed contamination of the beach with cyanide, ammonia, and polycyclic aromatic hydrocarbons (PAHs) with associated potential health risks. The incident was then referred to the local health authorities for investigation. METHODS: The investigation was carried out in four stages: comprehensive sampling and analysis to identify the extent of contamination, followed by an assessment of risk to health; establishment of a long term monitoring programme to identify any changes in contaminant concentrations; investigation of the effects of the contamination on shellfish; and review of the routine monitoring data and current sampling strategy. RESULTS: The initial investigation confirmed that the beach was contaminated, with the most likely source being the adjacent former gasworks site. The level of contamination was not found to be likely to pose a hazard to users of the beach. However, subsequent investigation of shellfish in the area led to warning signs being erected on the beach to prevent human consumption of mussels contaminated with PAHs. CONCLUSIONS: Several lessons can be learnt from this investigation, which can be applied to incident management more generally: the importance of collaboration and coordination; the need for early involvement of the health authority; and the importance of carrying out appropriate sampling and analysis as soon as possible, to assess the risk to health and the environment.
Ammonia↗