PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Waste Management”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,441 records · Page 80Linked to original sources
PubMed2006

Uranium induces oxidative stress in lung epithelial cells.

Uranium compounds are widely used in the nuclear fuel cycle, antitank weapons, tank armor, and also as a pigment to color ceramics and glass. Effective management of waste uranium compounds is necessary to prevent exposure to avoid adverse health effects on the population. Health risks associated with uranium exposure includes kidney disease and respiratory disorders. In addition, several published results have shown uranium or depleted uranium causes DNA damage, mutagenicity, cancer and neurological defects. In the current study, uranium toxicity was evaluated in rat lung epithelial cells. The study shows uranium induces significant oxidative stress in rat lung epithelial cells followed by concomitant decrease in the antioxidant potential of the cells. Treatment with uranium to rat lung epithelial cells also decreased cell proliferation after 72 h in culture. The decrease in cell proliferation was attributed to loss of total glutathione and superoxide dismutase in the presence of uranium. Thus the results indicate the ineffectiveness of antioxidant system's response to the oxidative stress induced by uranium in the cells.

Acetylcysteine↗
PubMed2005

Evaluation of wetland and tertiary wastewater treatments for estrogenicity using in vivo and in vitro assays.

The effects of wetland wastewater treatment on estrogenic activity and estrogenic activity of water after tertiary treatment were evaluated using in vivo (rainbow trout vitellogenin [VTG] expression) and in vitro (yeast estrogen screening) assays. Juvenile rainbow trout exposed to tertiary-treated wastewater from the Green Acres Treatment Plant in Orange County Water District had increased plasma VTG levels compared with control fish. When trout were exposed to wastewater-dominated water before it entered into Prado Wetland (Riverside County, CA), VTG concentrations were increased above those of controls and were not significantly different from fish exposed to water exiting the wetland. VTG E2-equivalent concentrations (EEQs) of the water samples from the Green Acres Plant were 16.92 +/- 16.49 ng/L. Activity of water entering Prado Wetland was 29.80 +/- 28.41 ng/L EEQ, and water exiting was 24.34 +/- 23.17 ng/L EEQ. In vitro assays estimated that estrogenic activity of water from the Green Acres Plant was <1 ng/L EEQ, whereas water entering and exiting Prado Wetland had yeast estrogen screening EEQs of 2.57 and <1 ng/L, respectively. Our results suggest that environmental estrogens that are not potent estrogen-receptor ligands exist in wastewaters from the Green Acres Plant as well as water entering and exiting Prado Wetland. Wetland treatment did not remove environmental estrogens in the water. Our results also suggest that in vitro assays may underestimate estrogenic activity of sampled water.

Animals↗
PubMed1997

Ecotoxicology for risk assessment in arid zones: some key issues.

In the hot arid zones of the world, ecotoxicological research is in statu nascendi. In these zones, the major sources of contamination by toxicants are: (1) plant protection and vector control in wet zones; (2) large-scale crop protection campaigns in dry and ephemeral wet zones; (3) refuse and obsolete pesticides in dry zones; and (4) mining. Economic development in many of these zones requires an adequate knowledge of certain basic principles, i.e., where extrapolating existing knowledge does not apply. The vulnerability of ecosystems to contaminants is closely related to water flow. In dry areas, species are susceptible to factors that interfere with the ecophysiological properties regulating water loss. Most hot arid areas are found at low latitudes where temperatures show striking extremes both in time and space. Living organisms are physiologically resistant and/or show adaptive behavior to these temperature extremes. Very little is known about the effects of toxicants on these key resistant and adaptive functions, although by extrapolation a few assumptions can be made. The effects of hyperthermia, for instance, can be aggravated by GSH depleting substances, and the temporary disabling effects characteristic of many pesticides may prove fatal under these circumstances. Most wet areas show a spatial concentration of both human activity and wildlife. In mesic zones, the contamination of water represents a health risk to both humans and other living organisms. The vast majority of aquatic communities are those inhabiting temporary pools and streams. Their populations are characterized by short reproductive cycles and/or long dormant stages. Toxicants affecting growth in these areas have been shown to have a deleterious effect. In a synthesis of existing knowledge the most prominent gaps are identified and priorities for further research are made.

Animals↗
PubMed1999

Oxidation of 2,4-dinitrophenol by hydrogen peroxide in the presence of basic oxygen furnace slag.

A treatment process was developed when basic oxygen furnace slag (BOF slag) and hydrogen peroxide were used to oxidize 2, 4-dinitrophenol from an aqueous solution. BOF slag, final waste slurry from steel making plants, contains about 12.5% by weight of ferrous oxide. In an acid solution, BOF slag can be dissociated to produce ferrous ions and react with hydrogen peroxide to produce hydroxyl radicals and oxidize 2,4-dinitrophenol. The results of the research demonstrated that the process had a significant capacity for oxidation of 2,4-dinitrophenol from the aqueous phase. Various factors critical to the oxidation of 2,4-dinitrophenol were studied, including hydrogen peroxide concentration, concentration of BOF slag, initial concentration of 2,4-dinitrophenol, and pH value of solution. Experimental results proved that 100 mg/L 2, 4-dinitrophenol and its oxidation intermediate could be totally decomposed within 60 min by 10 g/L BOF slag, 0.18 g/L hydrogen peroxide and pH 2.8 +/- 0.2. The optimum hydrogen peroxide concentration for degradation of 100 mg/L of 2,4-dinitrophenol is between 0.09 g/L and 0.18 g/L as 10 g/L BOF slag in the solution of pH 2.8 +/- 0.2. A hydrogen peroxide concentration higher than 0.18 g/L is disadvantageous to the oxidation process. The oxidation efficiency increased with the increase of BOF slag concentration at 0.18 g/L hydrogen peroxide dose. The best pH value of the solution is in the vicinity of 2.8. An oxidation reaction mechanism was proposed for predicting the concentration changes of 2, 4-dinitrophenol, ferrous ion, and hydrogen peroxide.http://link. springer-ny.com/link/service/journals/00244/bibs/37n4p427.++ +html</HEA

2,4-Dinitrophenol↗
PubMed2000

A multidisciplinary approach to assess history, environmental risks, and remediation feasability of soils contaminated by metallurgical activities. Part A: chemical and physical properties of metals and leaching ability.

Three soils contaminated by heavy metals (HMs) and aliphatic hydrocarbons originating from different industrial sources were characterized in a multidisciplinary study combining chemical, physical (Part A), and mineralogical (Part B) approaches to define history, environmental risks, and remediation feasibility. These were an agricultural soil located nearby a Zn/Pb smelter and two soils from a steel metallurgical (siderurgy) waste land. High Pb and Zn contents were reported for all, and high Cr, Cd, and aliphatic hydrocarbons were present in different combinations in two out of three soils. Carbonate matrixes more strongly cemented fine particles in the agricultural soil than in both siderurgical ones, but buffering capacities were stronger in the latter. After the disruption of these cements by ultrasounds, HM were concentrated in the <50-microm fraction of the agricultural and of one siderurgical soil. Sequential extractions indicated for all the soils a preferential association of HM with carbonates, Fe-Mn oxides, organic matter, and sulfides. The stirring of one siderurgical soil with water resulted in an immediate leaching of hexavalent chromium (0.3 mg x L(-1)) involving potential ecotoxicological risks.

Feasibility Studies↗
PubMed2000

A multidisciplinary approach to assess history, environmental risks, and remediation feasability of soils contaminated by metallurgical activities. Part B: direct metal speciation in the solid phase.

Three soils contaminated by industrial smelting activities previously characterized using chemical and physical approaches (Part A, Venditti et al. [2000] Arch Environ Contam Toxicol [in press]) were further investigated through a complementary mineralogical approach. X-ray diffraction allowed identification of the main mineral components: carbonates (calcite, siderite) and iron oxides (magnetite, hematite, goethite) prevailed in both siderurgical soils, and siliceous compounds were more abundant in the agricultural soil. Scanning electron microscopy coupled with energy dispersive x-ray microanalysis showed that carbonates and oxides contained low amounts of heavy metals (HMs), but the potential solubility of such species under acidic conditions associated to their abundance may result in a high mobility of associated contaminants. Microanalysis also revealed peculiar minor mineral forms (metallic nodules, alloys, ore residues) that were highly informative about the history of soil contamination. Small metal-rich particles were observed (brass, lead and zinc oxides). In such compounds, HMs showed high chemical stability and were consequently poorly mobile and toxic, but also poorly removable through chemical leaching. A risk of mechanical dispersion was suggested for these particles, particularly after the chemical and/or mechanical disruption of carbonate cements. These features allowed completion and confirmation of the conclusions achieved after chemical and physical investigations, providing accurate information about the history, environmental risks and remediation feasability of industrial soil contamination.

Feasibility Studies↗
PubMed2002

An update on the use of unconventional substrates for biosurfactant production and their new applications.

Biosurfactants are valuable microbial amphiphilic molecules with effective surface-active and biological properties applicable to several industries and processes. Microbes synthesize them, especially during growth on water-immiscible substrates, providing an alternative to chemically prepared conventional surfactants. Because of their structural diversity (i.e., glycolipids, lipopeptides, fatty acids, etc.), low toxicity, and biodegradability, these molecules could be widely used in cosmetic, pharmaceutical, and food processes as emulsifiers, humectants, preservatives, and detergents. Moreover, they are ecologically safe and can be applied in bioremediation and waste treatments. They can be produced from various substrates, mainly renewable resources such as vegetable oils, distillery and dairy wastes, which are economical but have not been reported in detail. In this review, we report advances made in using renewable substrates for biosurfactant production and their newer applications.

Biotechnology↗
PubMed2002

The influence of lignin content and temperature on the biodegradation of lignocellulose in composting conditions.

The aim of this research was to study the influence of lignin content and composting temperature on the biodegradation of lignin-containing pulp and paper products in a controlled composting test (European standard prEN 14046). Lignin reduced the biodegradation of the samples, and there was a linear correlation between the lignin content and the biodegradation of pulp and paper products at 58 degrees C. The influence of incubation temperature (35, 50 and 58 degrees C) on biodegradation was studied using bleached kraft paper containing 0.2 wt% lignin and mechanical pulp (stone-ground wood) containing 24-27 wt% lignin. Mechanical pulp biodegraded better at lower temperatures, while kraft paper biodegraded well at all three temperatures. Microbial activity was evaluated by measuring CO(2) evolution and the change in ATP content, and fungal biomass by measuring the ergosterol content during the composting experiments. Kraft paper strongly increased microbial activity during the controlled composting test, but the activity returned to the background level at the end of the composting test. The proportion of sample carbon converted to microbial biomass carbon was considerably higher at lower incubation temperatures. Changes in microbial community structure during biodegradation of mechanical pulp and kraft paper at 50 degrees C were studied by the PCR-based technique denaturing gradient gel electrophoresis. Changes in the microbial community were observed during the intensive degradation phase of kraft paper.

Bacteria↗
PubMed2002

An immobilised catalase peroxidase from the alkalothermophilic Bacillus SF for the treatment of textile-bleaching effluents.

A catalase peroxidase (CP) from the newly isolated Bacillus SF was used to treat textile-bleaching effluents. The enzyme was stable at high pH values and temperatures, but was more sensitive to deactivation by hydrogen peroxide than monofunctional catalases. Based on the Michaelis-Menten kinetics of the CP, a model was developed to describe its deactivation characteristics. The enzyme was immobilised on various alumina-based carrier materials with different shapes and the specific activity increased with the porosity of the carrier. The shape of the carrier had an important influence on the release of oxygen formed during the catalase reaction from the packed-bed reactor and Novalox saddles were found to be the most suitable shape. Bleaching effluent was treated in a horizontal packed-bed reactor containing 10 kg of the immobilised CP at a textile-finishing company. The treated liquid (500 l) was reused within the company for dyeing fabrics with various dyes, resulting in acceptable colour differences of below Delta E*=1.0 for all dyes.

Bacillus↗
PubMed2006

Selenite reduction by a denitrifying culture: batch- and packed-bed reactor studies.

Selenite reduction by a bacterial consortium enriched from an oil refinery waste sludge was studied under denitrifying conditions using acetate as the electron donor. Fed-batch studies with nitrate as the primary electron acceptor showed that accumulation of nitrite led to a decrease in the extent of selenite reduction. Also, when nitrite was added as the primary electron acceptor, rapid selenite reduction was observed only after nitrite was significantly depleted from the medium. These results indicate that selenite reduction was inhibited at high nitrite concentrations. In addition to batch experiments, continuous-flow selenite reduction experiments were performed in packed-bed columns using immobilized enrichment cultures. These experiments were carried out in three phases: in phase I, a continuous nitrate feed with different inlet selenite concentration was applied; in phase II, nitrate was fed in a pulsed fashion; and in phase III, nitrate was fed in a continuous mode but at much lower concentrations than the other two phases. During the phase I experiments, little selenite was removed from the influent. However, when the column was operated in the pulse feed strategy (phase II) or in the continuous mode with low nitrate levels (phase III), significant quantities of selenium were removed from solution and retained in the immobilization matrix in the column. Thus, immobilized denitrifying cultures can be effective in removing selenium from waste streams, but nitrate-limited operating conditions might be required.

Acetates↗