The chemical behavior of binuclear oxygen-bridged nitratonitrosylruthenium complex was studied in neutral aqueous solution containing sodium nitrate. This binuclear complex has been referred to for convenience as (Ru-O-Ru) nitrate, and is formed in reactor fuel-reprocessing through solvent extraction. Following facts have been found. (1) Nitrosyl groups of the original binuclear complex change to nitro or nitrato group by air-oxidation. (2) A charge-negative mononuclear aquo-ruthenyl complex with nitro and nitrato groups is formed, presumably due to the decomposition and air-oxidation of (Ru-O-Ru) nitrate.
A method for the determination of chlorobiphenyl in rat adipose tissue by neutron activation analysis is described. Adipose tissue from the tritiated chlorobiphenyl loaded rat was extracted with nhexane, and the extrat was partially purified by thin layer chromatography. Both crude and partially purified extract were used for analysis. The extracted material was sealded in a quartz ampoule while cooling with dry ice, and activated in a research reactor, Model TRIGA-II, at 4.4×1012 n/cm2⋅sec for 30 minutes. After cooling, ampoule was cleaned with diluted nitric acid, distilled water and acetone, and heated in electric furnace at 650°C for 10 minutes for pyrolysis of extract. Ampoule was then broken in 5%NaOHand H2O2solution (30: 1/ν: ν) containingNH4Clas a chlorine carrier to recover38Clin solution. To eliminate24Nacontamination chlorine was precipitated asAgCIand the precipitate was washed withHNO3and distilled water followed by redissolving in ammonium solution. Precipitating and washing were repeated again to get the final precipitate for assay of radioactivity. The radioactivity was measured with38Clγ-ray spectrum and its half life of 37.5 minutes. The sensitivity of the method was 0.1 micro gram. The value of chlorobiphenyl in adipose tissue was calculated assuming that it exists in fat without any changes in structure. At the same time, a method of measuring tritium labelled chlorobiphenyl with a liquid scintillation counter was carried out and a comparative study of both measured values made. The validity of values obtained by this assay procedure was confirmed by the demonstration that the value agreed with those determined independently by the analysis based on the amount of tritium activity in the extracted material.
The uptake of radioactive ruthenium by freshwater organisms in a biocenose was studied in an aquarium ecosystem which consisted of natural river water, duckweeds, mud snails, river snails, freshwater mussels, crucian carps and bottom sands. The aquarium was equipped with a filtration-aeratian apparatus. After a single addition of106Ru in nitrosyl ruthenium nitrato complex forms into the aquarium ecosystem, the uptake and distribution of106Ru in organisms were observed. The loss of106Ru from organisms were also studied. The radioactive concentration in rearing water rapidly decreased in 1 or 2 days and then maintained a constant level. The radioactive concentrations of106Ru in organisms reached peaks in 1 or 2 days, then gradually decreased with a gradual tendency to reach an equilibrium state. The deposition of106Ru in upper layer of bottom sands reached an equilibrium state in about 7 days. The average concentration factors for106Ru in organisms showed a decreasing tendency in following order: duckweeds, mud snails, river snails, freshwater mussels and crucian carps. In soft tissues of mud snails, freshwater mussels and river snails, the concentration factors for106Ru (RuNO-nitrato) were less than about several times in rearing single species. However, in crucian carps no significant difference of the concentration factor for 106Ru was observed with different rearing conditions. In crucian carps, about 80% of total radioactivity was distributed in visceral mass including digestive tract. The loss of106Ru in chlorocomplex forms from some organisms was more rapid than that of ruthenium in nitrosyl nitrato complex forms. Two biological half-lives of106Ru were observed in some tissues.