Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “WATER 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.

At least 163 records · Page 9Linked to original sources
PubMed1971

Rapid quantitative method for Salmonella detection in polluted waters.

A procedure has been developed for the enumeration of salmonellae in polluted waters using several modifications of existing techniques. Confirmation of salmonellae is achieved within 48 hr. This procedure includes selective enrichment in m-Tetrathionate Broth (22 +/- 1 hr), plating on Brilliant Green Sulfa Agar (20 +/- 1 hr), and confirmation by flagellar (H) agglutination of the growth in a mannosecontaining medium (6 +/- 1 hr). An incubation temperature of 41.5 C was used throughout this procedure. Dilution to extinction techniques (most probable number) were employed to enumerate salmonellae. Large sample volumes were concentrated through the use of membrane filters. This technique proved to be rapid and reliable for the enumeration of salmonellae in water, waste water, and waste-water sludges.

Agar↗
PubMed2003

Treatment of waters polluted with crude oil and heavy metals by means of a natural wetland.

In the Dolni Dubnik oil deposit, Northern Bulgaria, waters polluted with crude oil and heavy metals (iron, manganese, zinc, cadmium, lead, copper) were treated by means of a natural wetland located in the deposit. The waters had a pH in the range of about 4.5-6.5 and contained about 1-5 mg/l oil. The concentrations of heavy metals usually were about 2-4 times higher than the relevant permissible levels for waters intended for use in the agriculture and industry. The watercourse through the wetland covered a distance of about 100 m and the water flow rate varied in the range of about 0.2-0.8 l/s. The wetland was characterized by an abundant water and emergent vegetation and a diverse microflora, including different oil-degrading bacteria and fungi. The treatment of the polluted waters by means of the above-mentioned wetland markedly depended on the temperature but was efficient during the different climatic seasons, even during the cold winter months at temperatures close to 0 degrees C. The oil content in the wetland effluents in most cases was decreased to less than 0.2 mg/l, and the concentrations of heavy metals were decreased below the relevant permissible levels. The removal of oil was connected with its microbial degradation. The removal of heavy metals was due to different processes but the microbial dissimilatory sulphate reduction and the sorption of metals on the organic matter and clay minerals present in the wetland played the main role.

Agriculture↗
PubMed1982

Dye-coupled electrode system for the rapid determination of cell populations in polluted water.

We determined cell populations in polluted waters by using a fuel cell-type electrode. The electrode was constructed from a platinum anode, a silver peroxide cathode, and a membrane filter for retaining microorganisms. The principle of cell number determination is based on sensing a redox dye reduced by the microorganisms with the electrode. Sample solutions containing microorganisms were membrane filtered, and the resulting filter containing microbial cells was attached to the surface of a platinum anode. The electrode was immersed in phosphate buffer solution (0.05 M, pH 7) containing a redox dye (2,4-dichlorophenol-indophenol), and the current generated was measured. The response time of the electrode system was 10 to 20 min, and the current generated was proportional to cell populations above 10(4) cells/ml.

Bacillus subtilis↗
PubMed1999

Efficacy of new formulations of the microbial larvicide Bacillus sphaericus against polluted water mosquitoes in Thailand.

Two new water dispersible granular (WDG) formulations of the microbial control agent Bacillus sphaericus (strain 2362) were extensively evaluated in polluted waters against Culex quinquefasciatus in Thailand. The studies were carried out in stagnant as well as flowing waters during August 1997 to July 1998. The trial period covered both rainy and dry seasons. The two WDG formulations of B. sphaericus tested were low potency (350 ITU/mg) and high potency (630 ITU/mg) products. Both formulations were used at various rates to determine initial efficacy and longevity. The high potency formulations provided excellent control (80 to 90%) of immature mosquitoes at the rates of 50 to 100 mg/ m2, while the less potent formulation yielded similar control at the rates of 89 to 250 mg/m2. Longevity of control was anywhere from one week to four weeks or longer depending on the dosage, habitat, and environmental conditions. Two treatments with low dosages of Bacillus thuringiensis ssp. israelensis WDG provided short-term control lasting for one week. Frequent episodes of heavy rains facilitated long-term suppression of immature mosquitoes in klongs by flushing out the larvae. In the absence of rain, the longevity of treatments in flowing waters was shorter than in the presence of rain. Rain, however, had some but not pronounced effect on longevity in the stagnant water habitats. Operation of floodgates controlling water flow from stagnant water habitats into the Chaophrya River had greater influence on the abundance of mosquito immatures in the ponded polluted waters under dwellings. Precipitation, adding large amounts of water, was probably responsible for diluting the control agents and also resulted in lower counts of immatures per unit volume of water. These variables could influence the efficacy (especially longevity) of treatments employing formulations of microbial agents in operational control programs. The WDG formulations are preferred over other formulations, such as granules, because the former contain larger quantities of toxins per unit mass than the latter and are easily applied as aqueous sprays. Potent formulations with greater content of active ingredients are less costly to ship and transport to distant areas.

Animals↗
PubMed1996

Effects of water pollution on the gill apparatus of fish.

The study was designed to investigate the influence of water pollution on gill apparatus. Specimens of Nile tilapia were collected from a polluted site in the São Paulo metropolitan area (Billings reservoir) and from a "clean" area. Fish from the polluted site showed a chronic inflammatory process in the distal region of the gill filaments, with epithelial hyperplasia. The raker length was increased and hypersecretion occurred, with a considerable volume of alcian blue-positive mucin on the epithelium of the rakers and a smaller volume of periodic acid-Schiff-positive mucin on the epithelial surface of the filaments. The rigidity of mucus in fish from the polluted site was increased, but no abnormalities in the viscosity to elasticity ratio or in mucus "wettability" were observed.

Animals↗
PubMed2001

The struggle for a cleaner urban environment: water pollution in Malmö 1850-1911.

This article focuses on the emergence of water pollution problems in the city of Malmö and on how they were discussed and solved. Various countermeasures were proposed and considered, but finally the discharge of wastewater into the Sound of Oresund was regarded as the best solution. As a result, a local pollution problem was transformed into a regional issue. The solutions adopted in Malmö are briefly compared with decisions made in Gothenburg and Stockholm.

Cities↗
PubMed2006

Cost-effective control of interdependent water pollutants.

Excess nutrient loads to coastal waters lead to increased production of algae, which when decaying cause oxygen depletion in bottom sediments, which in turn leads to major changes in marine ecosystems. A cost-minimization model was investigated in which nitrogen and phosphorus were assumed to interact with respect to algae production. It was investigated under what conditions only a single nutrient should be decreased and when it is cost-effective to decrease both nutrients. The model was applied to the Baltic Proper, which is the largest of the seven major basins in the Baltic Sea. Results showed that the stringency of the environmental target, as well as assumptions regarding substitutability between nutrients, are important factors to determine the nutrient on which to focus. Uniform decrease rates for emissions are often used in international agreements, and the results of this model showed that the costs of making such proportional decreases could be substantial.

Ecosystem↗
PubMed2005

Changes in mussel Mytilus galloprovincialis protein profile as a reaction of water pollution.

In the present report the changes in mussels Mytilus galloprovincialis protein profile, as a reaction of water pollution, is presented. The antioxidant capacity was determined by the efficacy to scavenge the derived radical in mussel samples using the Trolox Equivalent Antioxidant Capacity (TEAC) assay. The highest percentage of inhibition was estimated in protein mussels from the dirty area (DM) in comparison with the clean samples (CM). The amounts of both zinc and copper determined by atomic spectroscopy were significantly higher in the protein mussels from the dirty than from the clean areas (P<0.05). Fourier Transform Infrared (FT-IR) spectroscopy and fluorescence revealed specific qualitative changes in secondary and tertiary structures of mussel proteins from the dirty area by the shift in the amides I and II positions and fluorescence intensity. Estimated temperature and enthalpy of denaturation in the protein mussels well correlated with fluorescence and spectroscopic measurements and showed the changes influenced by water pollution.

Animals↗
PubMed2003

[Emergency counterplan for drinking water pollution accident].

After the almost nation-wide outbreak of SARS this year, all the health administration agencies have made attempt to analyze the origin of the epidemic and draw lessons from the measures taken against it, hoping to be better able to cope with such potential public health threats. For effectively preventing and timely controlling drinking water pollution accident so as to ensure the sanitation of life drinking water, it is of great importance to prepare emergency counterplan beforehand against such accident. In this article the author proposes the emergency counterplan against urban drinking water pollution on the basis of established laws and regulations of the state and Beijing municipality.

Emergencies↗
PubMed2003

Political economy of transnational water pollution: what do the LMB data (1985-2000) say?

On the basis of the cross-section and time-series data of the Lower Mekong Basin (LMB)--including large sections of Thailand, Lao PDR, Vietnam, and Cambodia, we find little evidence in support of the environmental Kuznets curve (EKC) hypothesis. Instead, our regressions support the general views that water pollution had been positively related to income level and that, as a result of the end of the Cold War era, it had been significantly reduced in the 1990s vis-à-vis the 1980s. In most circumstances, water resources were more seriously polluted in the transnational border areas than in the other areas. Specifically, the estimated coefficients on the political boundary dummies show that political influence on transnational water pollution was more significant in areas near "the international border along which the river runs" (denoted by BORDER2) than in places near "the international border across which the river runs" (denoted by BORDER1). The estimated coefficients on the ASEAN dummy present some information about the positive role of the Association for Southeast Asian Nations (ASEAN) membership in the reduction of transnational water pollution. Finally, the country-specific dummies are found to present conflicting information about the transnational differences of water pollution, although Thailand is found to have the least water pollution in the LMB.

Asia↗
PubMed2005

Ecotechnology: basis of a new immission concept in water pollution control.

Beyond the traditional load reduction also an ecosystem-internal mechanism can be used to minimise the effects of water pollution. The control of the internal mechanisms is achieved through the optimisation of the ecosystem structure. This ecotechnology principle is based on the idea to reduce as much as possible the gap between the current (suboptimal) structural status and the optimum structure by intentional manipulations. The spectrum of such manipulations is very broad. A few examples are demonstrated. They comprise physical (e.g. stream morphology), chemical (e.g. enhancing the redox potential at the sediment-water interface) and biological (e.g. enhancing stocks of predatory fishes) control measures. It can be supposed that a new immission concept including the ecotechnology principle could be much more adequate to the demand of modern water pollution control than the traditional emission and imission concepts.

Ecology↗