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At least 19 recordsLinked to original sources
PubMed2004

Fate of heavy metals and radioactive metals in gasification of sewage sludge.

The fates of radioactive cadmium, strontium, cesium, cobalt, arsenic, mercury, zinc, and copper spiked into sewage sludge were determined when the sludge was gasified by a process that maximizes production of char from the sludge (ChemChar process). For the most part the metals were retained in the char product in the gasifier. Small, but measurable quantities of arsenic were mobilized by gasification and slightly more than 1% of the arsenic was detected in the effluent gas. Mercury was largely mobilized from the solids in the gasifier, but most of the mercury was retained in a filter composed of char prepared from the sludge. The small amounts of mercury leaving the gasification system were found to be associated with an aerosol product generated during gasification. The metals retained in the char product of gasification were only partially leachable with 50% concentrated nitric acid.

Environmental Monitoring↗
PubMed1999

Relationship between the biodistributions of radioactive metal nuclides in tumor tissue and the physicochemical properties of these metal ions.

This study was undertaken to elucidate the relationship between the biodistribution of radioactive metal nuclides in tumor tissue and its physicochemical properties. Potassium analogs (86Rb, 134Cs, 201Tl) were taken up into viable tumor tissue, although 22Na concentrated in necrotic tumor tissue. 67Ga and 111In were more predominant in inflammatory tissue than in the viable and necrotic tumor tissue. 169Yb and 167Tm accumulated in viable tumor tissue and tissue containing viable and necrotic tumor tissue. 67Ga, 111In, 169Yb and 167Tm were bound to the acid mucopolysaccharide with a mol. wt. of about 10,000 daltons in the tumor tissue. 46Sc, 51Cr, 95Zr, 181Hf, 95Nb, 182Ta, and 103Ru were highly concentrated in inflammatory tissue and were bound to the acid mucopolysaccharides with a mol. wt. exceeding 40,000 daltons. 65Zn and 103Pd concentrated in viable tumor tissue and were bound to the protein in the tissue. The results suggest that the difference in intra-tumor distribution of these elements is caused by a difference in the binding substances (or status) of these elements in the tissues, and the binding substance is determined by physicochemical properties of the elements. We therefore conclude that the biodistribution of radioactive metal ions in tumor tissue is determined by its own physicochemical properties.

Animals↗
PubMed1982

Encapsulation, with high efficiency, of radioactive metal ions in liposomes.

The encapsulation of radioactive metalic cations, such as 111In3+ or 67Ga3+, in the internal aqueous compartment of liposomes can be achieved with an efficiency of about 90%. The efficient loading of a high specific activity of cations into liposomes involves the transport of 111In3+ or 67Ga3+ through the lipid bilayer to an encapsulated strong chelate, such as nitrilotriacetic acid, by 8-hydroxyquinoline, in conjunction with an efficient anion-exchange resin technique for the removal of the external cations. The efficiency of loading cations to liposomes is affected markedly by the concentration of 8-hydroxyquinoline-metal, and the presence of the chelating agents in the loading incubation mixture. However, the loading efficiency is not affected by the pH of the internal aqueous compartment of liposomes over a range of pH 5-9, the concentration of the liposomes, the method of liposomal preparation, the lamellar structure of the liposomes, and the composition of liposomes. Furthermore, the loading procedures do not appear to affect the size and the permeability of liposomes. There is a good agreement in the tissue distributions of the liposomes prepared by the present loading methods and those by the conventional method of encapsulation by sonication. Liposomes entrapping high specific activity of 67Ga3+ or 111In3+ will be useful for future studies of the in vivo kinetics of liposomes by the combined techniques of scintigraphic imaging and the gamma-ray perturbed angular correlation.

Animals↗
PubMed1982

Tumor imaging with radioactive metal chelates conjugated to monoclonal antibodies.

High-resolution gamma camera images of mouse erythroid tumors were obtained by use of leukemia cell-specific monoclonal antibodies labeled with bifunctional radioactive metal chelates. Small tumors (200 to 300 milligrams) were visible without subtraction or enhancement 1 to 5 hours after injection of antibody. Chelate-derivitized monoclonal antibodies permit targeting of a broad spectrum of radioisotopes, including those that are optimum for agamma for gamma camera imaging or positron tomography, as well as those that are tumoricidal.

Animals↗
PubMed1989

Radioactive metal complexes with affinity for tumors. II. Biodistribution of radioactivity in cellular and subcellular fractions of tumor tissues.

The 99mTc and 57Co complexes of ethylenediamine-N,N-diacetic acid (EDDA) are accumulated in tumor tissue. The complexes and related radioactive compounds were administered to experimental animals bearing Ehrlich tumor, and the blood, tumor, abscess, and other tissues were separated, fractionated and analyzed. In blood, the EDDA complexes of 99mTc and 57Co were in dialyzable forms, whereas other tumor-nonlocalizing compounds were in undialyzable or protein-bound forms. The tumor/blood and tumor/muscle ratios of the radioactivity showed that the complexes had the high affinity for tumor tissues. Density gradient centrifugation analysis of the ascites tumor tissues showed that a significant amount of the radioactivity of the complexes was present in tumor cells. Subcellular fractionation of solid tumor tissue showed that the radioactivity was present in nuclear fraction.

Animals↗
PubMed2006

A radioactive metal processing industry perspective source.

The current U.S. economic environment for the disposition of radioactive waste, including very-low-activity metals, is currently experiencing relatively low radioactive disposal costs and readily available disposal space. Despite the recent market increase in demand for recycled scrap metal commodities, there is still little change in the behavior of the nuclear industry (including radioactive waste processors and radioactive scrap metal recyclers) to pursue the recycling of potentially contaminated scrap metal. The relatively low cost of traditional radioactive waste disposal combined with the perceived risks associated with recycling of previously contaminated metals means that most U.S. radioactive facility managers and stakeholders will elect not to recycle. Current technology exists and precedence has been set for prescreening (by means of bulk radioactive assay techniques) scrap metal that is not contaminated and diverting it to industrial landfills for disposal. Other processes also allow some radiologically contaminated metals to be melted and recast into products with low, but acceptable, activity levels for restricted use in the nuclear industry. A new concept is being considered that would create a centralized licensed facility for the process and disposition of "very-low-activity" metals for "directed first use." The advantages to this type of approach would include a standardized method for licensing the clearance process.

Decision Making↗
PubMed2006

Pollution of the Begej Canal sediment--metals, radioactivity and toxicity assessment.

The Begej Canal is one among a large number of canals in Vojvodina (Northern Province of Serbia and Montenegro). The paper describes a study of metal and radioactivity contamination of the Begej Canal sediment. It is also concerned with the evaluation of sediment acute toxicity based on standard test species Daphnia magna and simultaneously extracted metals and acid volatile sulfides. The quality of sediment was assessed according to Dutch standards, but the results were also compared with some Canadian and USEPA (United States Environmental Protection Agency) guidelines for sediment quality. The results showed severe pollution with chromium, copper, cadmium and zinc, whereby the anthropogenic origin of these contaminants was indicated. The tests of toxicity of sediment pore water to D. magna, gave no indication of the presence of substances in acutely toxic concentrations to this species. It can be speculated that, despite of high metal contents, the observed toxicity was low because of the high contents of clay and iron, as well as sulphide. Also, based on a comparison with the Danube sediment and Vojvodina soil in general, the data of the Begej sediment contamination with 238U and 137Cs. The 137Cs data were used for approximate dating of the sediment. No traces of contamination by nuclear power plants in the region were found, while the presence of technologically enhanced naturally occurring radioactive materials (TENORM) was proved. Conclusions based on different criteria for sediment quality assessment were in some cases contradictory. Study also showed that radioactivity aspects can be useful in sediment quality surveys. The obtained results will be invaluable for the future activities regarding integrated water management based on EC Water Framework Directive (2000/60/EC) in the Danube basin, and particularly in the region of crossborder water body of the Begej Canal.

Animals↗
PubMed2001

Ion pairing as a strategy for extraction by modified supercritical carbon dioxide: extraction of radioactive metal ions.

Supercritical fluid carbon dioxide was investigated for its potential to extract perrhenate ion pairs. This has implications for radioactive waste processing because Tc-99, the second row congener of Re, is produced in approximately 6% fission yield from nuclear fuel and pertechnetate is its most common chemical form in aqueous environments. The variables examined to maximize extraction of the perrhenate ion pair were temperature, pressure, solvent modification, and ion-pairing agents. The tetrabutyl-ammonium cation was found to form the most efficient ion pair for extracting perrhenate using methanol-modified (approximately 10%) SFCO2 at 70 degrees C and 477 atm, with 0.083 mg of Re/g of SFCO2 extracted.

Journal Article↗