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At least 469 records · Page 26Linked to original sources
PubMed1978

Interaction of chemical pollutants and virus in a crustacean: a novel bioassay system.

A large group of shrimp, 23.3% of which had light patent Baculovirus infections, was divided equally into two groups. One group was exposed to the chemical stressor Aroclor 1254 (a polychlorinated biphenyl) at 0.7 ppb for 35 days in flowing seawater. The other group was maintained as a control group in flowing seawater. Viral prevalence in exposed shrimp samples increased with time at a significantly greater rate than did viral frequency in control shrimp. Viral prevalence in Aroclor-exposed shrimp survivors was 75% after 35 days, whereas in control shrimp, only 45.7% had patent viral infections. This finding suggests an interaction among chemical stressor (Aroclor 1254), host, and virus. The nature or mechanism of this interaction has not been defined, but the shrimp-virus system shows, promise for future bioassays of influence of low concentrations of pollutants on natural pathogenhost interactions.

Animals↗
PubMed1965

CRITERIA AND METHODS FOR ESTABLISHING MAXIMUM PERMISSIBLE CONCENTRATIONS OF AIR POLLUTION.

The article describes experience in the USSR in establishing standards for air pollution control. The author emphasizes that health considerations must be the main criterion in deciding permissible concentrations, which constitute the "hygienic" standards ultimately to be achieved. Economic and technological reasons may dictate temporary "sanitary" standards, which modify the requirements for a limited period. "Technological" standards relate to the economic and technological consequences of air pollution and do not concern health.The maximum permissible concentrations of toxic substances used in toxicology and industrial hygiene are not sufficiently stringent for general use, and control standards are therefore based on the results of tests carried out on animals and human subjects.Tests on animals show that certain concentrations of toxic substances cause functional changes (e.g., in higher nervous activity, cholinesterase activity, and excretion of coproporphyrin) as well as a number of protective adaptational reactions. The results are used to establish maximum permissible concentrations of pollutants within a 24-hour period.Tests on human volunteers provide a basis for determining the maximum average concentrations at a given time. Reactions to odorous substances give the olfactory threshold and the level of concentration causing respiratory and visual reflexes, as well as subsensory effects such as changes in light sensitivity and in the activity of the cerebral cortex.Morbidity statistics also provide evidence of harmful pollution, but cannot serve as a basis for establishing maximum permissible concentrations, which should aim not only at preventing illness but also at avoiding pathological and adaptational reactions.

Air Pollution↗
PubMed1981

Inducibility of aryl hydrocarbon hydroxylase in BALB/c/ki mice exposed to urban air pollution.

In two separate experiments BALB/c/ki mice were exposed to urban air pollution. Mice exposed to clean air served as controls. In both experiments there were no obvious quantitative or qualitative differences in lung or liver tissue examined by light microscopy. In both experiments higher aryl hydrocarbon hydroxylase activities and higher trace metal concentrations were observed in the mice exposed to polluted urban air. These data are interpreted in terms of health hazards of urban air pollutants.

Air Pollutants↗
PubMed1990

Modelling soil productivity and pollution.

Predictive models of soil and plant processes should be of much benefit both in developing and developed countries. They can assist in enabling agronomic practices to be better adjusted for differences in conditions; in avoiding disasters that can accompany change in land use; in minimizing waste and environmental pollution, and in modifying and implementing legislation. These views are discussed in the light of recent advances. Particular attention is drawn to (i) the excellent relationships linking average national yields, nutrient uptakes, etc. to single factors such as average fertilizer application; (ii) equations for predicting the behaviour of added chemicals and water in soil that have been obtained by rigorous deduction from physical and chemical laws; (iii) the discovery of semi-empirical, but nevertheless widely applicable quantitative relations for key soil and plant processes, and (iv) the formulation and use of computer models for field situations. There is a pressing need to find ways of presenting the outcome of this work so that it can be more widely applied in practice.

Agriculture↗
PubMed2004

Toxicity of the 13 priority pollutant metals to Vibrio fisheri in the Microtox chronic toxicity test.

The Microtox Acute Toxicity Test has been successfully used to measure the toxicity of metals and other pollutants at high concentrations (ppm) in selected environmental samples. However, metals and other toxicants are often found in much lower concentrations (ppb) in many municipal wastewaters and receiving waters. In order to assess the toxicity of these pollutants in these samples, a more sensitive toxicity assay is needed. The Microtox chronic toxicity test has been developed to measure the sublethal effect of toxicants over multiple generations of the test species, Vibrio fisheri. In this study, the toxicity of the 13 priority pollutant metals [i.e. As, Se, Cd, Cr (III and VI), Cu, Pb, Sb, Ag, Tl, Zn, Be, Hg and Ni] to V. fisheri was evaluated using the Microtox chronic toxicity test. In this test, the inhibitory concentration (IC), lowest observable effect concentration (LOEC), and no observable effect concentration (NOEC) were obtained after 22-h of incubation at 27+/-1 degrees C, by comparing the light output of the control to that of the test sample. Among the 13 priority pollutant metals, beryllium (Be) was found to be the most toxic in the test (LOEC=0.742-1.49 microg/l) while thallium (Tl) was the least toxic (LOEC=3840-15300 microg/l). The LOECs for copper (as Cu) and lead (Pb) in reagent (ASTM Type I) water were 6.78-13.6 microg/l and 626-1251 microg/l, respectively. The toxicity of copper sulfate (as Cu) in reagent water was shown and significantly reduced with the addition of natural organic matter (fulvic acid) or EDTA to the sample. The LOEC values for the 13 priority pollutant metals in this test were comparable to or lower than those reported for commonly used aquatic toxicity tests, such as the Ceriodaphnia dubia assay.

Benzopyrans↗
PubMed2002

Integrating pollution prevention technology into public policy: the case of professional wet cleaning.

This paper discusses opportunities to promote pollution prevention technologies through public policy, describing the case of dry cleaning. The crisis in dry cleaning is associated with the industry's reliance on perchloroethylene (PCE), the chemical cleaning solvent used by the vast majority of cleaners. The limits to the current pollution control or end-of-pipe system of laws and regulations and the search for nontoxic alternatives are analyzed in light of the environmental and occupational hazards associated with PCE use. Criteria to evaluate those alternatives are then described, including their application to professional wet cleaning, a commercially available pollution prevention alternative to PCE. The article concludes with an evaluation of several public policy instruments that could be used to promote the diffusion of professional wet cleaning as a potential solution to this regulatory crisis. These include environmental and occupational regulations designed to reduce or eliminate risk from exposure to toxic substances as well as incentive-based programs. Both barriers and opportunities for the use of each instrument are identified. This review reveals that, while the pollution control approach to public policy has deepened the regulatory crisis in the garment care industry, policy instruments are currently available to create an effective transition toward a pollution prevention outcome.

Carcinogens↗
PubMed1969

Reaction of airborne Rhizobium meliloti to some environmental factors.

Survival of Rhizobium meliloti 102F5 in aerosols at 20 C was maximal at high relative humidity (RH) and minimal at low RH. Relatively high concentrations of NO(2), SO(2), or formaldehyde were needed to significantly reduce viability of R. meliloti in aerosols at 50% RH. Except for the reduction in activity of formaldehyde by SO(2), there was no additive or antagonistic effect of mixing pollutants. High environmental RH enhanced bactericidal activity of NO(2) and SO(2). High RH minimized and low RH accentuated the biological effect of ultraviolet light of 300 to 400 nm wavelength.

Aerosols↗
PubMed2006

Atmospheric mercury emissions from polluted gold mining areas (Venezuela).

Soil, waste rock and mud from mercury-gold amalgamation mining areas of El Callao (Venezuela) are highly enriched in Hg (0.5-500 microg g(-1)) relative to natural background concentrations (<0.1 microg g(-1)). Mercury fluxes to the atmosphere from twelve polluted sites of this area were measured in situ (6 a.m. to 8 p.m.) using a Plexiglas flux chamber connected to a portable mercury analyzer (model RA-915+; Lumex, St. Petersburg, Russia). Mercury fluxes ranged between 0.65 and 420.1 microg m(-2) h(-1), and the average flux range during the diurnal hours was 9.1-239.2 microg m(-2) h(-1). These flux values are five orders of magnitude higher than both reported world background Hg fluxes (1-69 ng m(-2) h(-1)) and the regional values, which are in the range 2-10 ng m(-2) h(-1). The flux results obtained in this study are, however, similar to those measured at Hg polluted sites such as chloro-alkali plants or polymetallic ore mining districts (>100,000 ng m(-2) h(-1)). The results from this study also show that Hg emissions from the soil are influenced by solar radiation, soil temperature and soil Hg concentration. Our data suggest that solar radiation may be the dominant factor affecting Hg degrees emission since the major species of mercury in polluted soil is Hg degrees (85-97% of total Hg). The simple release of Hg degrees vapor is probably the dominant process occurring with incident light in the field. The apparent activation energy for mercury emission indicates that the volatilization of mercury mainly occurred as a result of the vaporization of elemental mercury in soil. The degree of Hg emission differed significantly among the soil sites studied, which may be due to variations in soil texture, organic matter content and soil compaction.

Air Pollutants↗
PubMed2001

[Extinction characteristics of TiO2 suspension for different band ultraviolet radiation].

This study focused on the global absorption characteristics of UVA, UVB and UVC radiation in the suspension of titanium-pollutant solution using 4-CBA-Na as a model pollutant. The result showed that the attenuation of ultraviolet in the suspensions conformed to Beer's Law, light intensity negative-exponentially attenuating with the optic path. The extinction coefficient increased with the titanium dosage by a quadratic polynomial law, which may be approximated by a linear function at lower dosage. The sum of the respective UVC or UVB extinction coefficient in pollutant solution and titanium-water suspension was found to approach the measured value in Titanium-Pollutant suspension. Larger extinction coefficient was observed for shorter UV wavelength, implying higher energy efficiency with UVC as ultraviolet source.

Catalysis↗
PubMed2002

Abnormalities of the attachment clamps of representatives of the family Diplozoidae.

A comparative study has been made of the haptoral morphology of four species of diplozoon (Monogenea: Diplozoidae) from the gills of fish exposed to different levels of water pollution in two river systems in eastern Europe. An examination of the haptors of Paradiplozoon homoion (Bychowsky & Nagibina 1959), Paradiplozoon ergensi (Pejcoch 1968) and Paradiplozoon megan (Bychowsky & Nagibina 1959) from chub caught in the River Morava, Czech Republic and of Diplozoon paradoxum (Nordmann 1832) from bream recovered from the River Volga, Russia has revealed abnormalities to the attachment clamps. Two abnormal conditions were found: structural alterations to the attachment clamps and changes in the number of attachment clamps; these occurred both singly and in combination. A higher frequency of abnormal attachment clamps was found in diplozoons from fish caught in the more polluted localities of both rivers. The abnormalities have been recorded and their morphology compared in the light of conditions of environmental stress.

Animals↗
PubMed2002

Accumulation of lead and cadmium in the marine prosobranch Nerita saxtilis, chemical analysis, light and electron microscopy.

The potential value of the marine prosobranch Nerita saxtilis as an efficient biological monitor to heavy metal pollution in the Red Sea was investigated. Storage ability of lead and cadmium was compared in shell, headfoot and digestive gland of the marine snail N. saxtilis collected from Al-Hamrauin area at El-kuseir (lead, 300.35 +/- 28.53 microg/l, 1,716 +/- 16.14. cadmium 20.01 +/- 1.8 microg/l, 161.72 +/- 21.4 mean +/- S.D. for water and sediment, respectively) relative to that of inhabiting marine water and sediment employing atomic absorption spectrometry to determine the organ with highest capability of heavy metal accumulation. The influence of metal storage on light microscopic structure of that organ was investigated. Also, the ultrastructure localization of storage sites in the same organ was determined employing transmission electron microscopy. The digestive gland was shown to accumulate both metals at conccntrations that are several orders of magnitude higher than those in the surrounding marine water. The bioaccumulation capability of lead and cadmium was ranked in the following order; digestive gland > headfoot > shell for lead and digestive gland > shell > headfoot for cadmium. In spite of its evident highest metal storage capability, no histopathological changes were observed in the digestive gland of that marine prosobranch. Enlarged electron dense vesicles and many granules were observed in ultrathin sections in digestive cells of these snails and are suggested to be the sites of storage of detoxified metals. The results of that finding indicate the possibility of using the marine prosobranch N. saxtilis as biomonitor for heavy metal contaminants in the Red Sea.

Animals↗
PubMed2006

Kinetics of photocatalytic VOCs abatement in a standardized reactor.

A standardized micro-pilot scale continuous flow apparatus has been built up, using two types of differential photoreactors, and equipped with a refined control of the working conditions in order to study the photocatalytic degradation as a way to abate VOCs in air. Kinetic measurements have been carried out on trichloroethylene (TCE), methanol and benzene as model pollutants. The absence of diffusional limitation and of reaction product effect on the kinetics have both been demonstrated under our working conditions. The influences of concentration, light flux and temperature on the initial degradation rate have been studied. A simple Langmuir-Hinshelwood kinetic model has been verified for TCE and methanol, whereas benzene degradation was more complex and did not follow this simple mechanism. The determined experimental data aim at being useful in the scaling-up of photocatalytic reactors.

Air Pollutants↗
PubMed1981

Thermocamera, a macroscopic method for the study of pollution with nitrous oxide in operating theatres.

Nitrous oxide (N2O) is used in high concentrations in inhalation anaesthesia and can serve as a tracer of other, more potent anaesthetic agents polluting the air of operating theatres. It has the quality of absorbing infra-red light with a characteristic peak of 4.5 micrometer in the absorption spectrum. N2O in the operating-room atmosphere will absorb infra-red light emitted from a heat screen, and can therefore be registered by an infra-red-camera equipped with a filter eliminating waves outside the 4.5 micrometer waveband. The method was tested during paediatric inhalation anaesthesia. The infra-red-camera measurements are semi-quantitative and sensitive to an extinction of about 1000 ppmcm, comparable to a N2O concentration of 100 ppm measured by an infra-red N2O monitor. It was demonstrated that major pollution occurs during mask anaesthesia and after extubation. The polluting gas is insufficiently evacuated by the operating theatre ventilation. The method makes it possible to visualize the dispersion of spilled or leaking N2O, and is therefore of value when constructing and evaluating new scavenging equipment and in producing educational material.

Absorption↗