90Sr and137Cs in fallout from Chernobyl in the Bucharest-Măgurele area during 1986–1987

This work shows the variation of⁹⁰Sr and¹³⁷Cs in atmospheric fallout in the Bucharest-Mgurele area during 1986–1987. The amount of⁹⁰Sr in the fallout was estimated to be about 900 Bq.m^–2 in 1986 and about 9.2 Bq.m^–2 in 1987. The amount of¹³⁷Cs was estimated to be 13300 and 615 Bq.m^–2 in 1986 and 1987, respectively.     

Preparation of Sn-β-alanine: A new freeze-dried kit to be labelled with99mTc for liver scintigraphy

Sn-alanine kits were prepared in lyophilized form containing 7.02·10^–2 M -alanine and 5.5·10^–4M stannous chloride dihydrate. The optimal pH value of the preparation was found to be equal to 4.3–5.1. The radiochemical purity and the stability of^99mTc-alanine were assessed by gel filtration column scanning techniques (GCS) and thin layer chromatography, and the labelling yield of the complex was higher than 95%. The organ distribution data in mice showed that more than 90% of the injected dose had been accumulated in the liver. However, a negligible amount of radioactivity was detected in the non-target organs. The stability of^99mTc-alanine was followed for 5 hours and the Sn-alanine kit was stable for at least 3 months.     

Kinetic analysis of99mTc-d, 1-HMPAO decomposition and the method of stabilization

The kinetics of^99mTc-d, 1-HMPAO decomposition is studied using home kits. The results showed that^99mTc-d, 1-HMPAO decomposition is a first-order reaction. The decomposition constant k is found to be 0.017±0.007h^–1 under the experimental conditions of 20°C, 185MBq/ml, pH 7.0. The stability of^99mTc-d, 1-HMPAO is affected not only by pH and radioactive concentration, but also by temperature. Using Immol/l gentisic acid as a stabilizer, 740MBq/ml of^99mTc-d, 1-HMPAO can be stabilized for 3h with the radiochemical purity above 80%.     

Statistical analysis of biodistribution of99mTc-colloid preparations

The results of radiochemical purity measurements for^99mTc–S colloid, 90.7±1.4, and^99mTc–Sn colloid, 98.9±1.2 obtained by ITLC (SG) with 80% methanol are given. The range of biodistribution normal values for^99mTc colloid preparations for animal organs is determined. The results of^99mTc–S and^99mTc–Sn colloid distribution in liver are 95.4±6.1% and 100,0±5.4%, respectively.     

Results of three years of monitoring239,240Pu and238Pu concentrations in airborne effluents from the V-1 nuclear power plant with VVER 440 reactors in Jaslovské Bohunice in Czechoslovakia

The concentration of^239,240Pu and²³⁸Pu in airborne effluents in the years 1985–1987 from two reactors VVER 440/total power of 880 MW/ of a nuclear power plant V-1 in Jaslovské Bohunice in Czechoslovakia, was determined. The concentration of^239,240Pu in effluents ranged from 1.0 to 30.8 Bq.m^–3 and of²³⁸Pu from 1.6 to 41.1 Bq.m^–3. The activity ratio²³⁸Pu/^239,240Pu in airborne effluents kept within the range of 1.0–2.4. Total annual discharged activities of^239,240Pu in 1985, 1986 and 1987 were 28.5, 12.7 and 12.2 kBq, respectively. Total annual discharged activities of²³⁸Pu in 1986 and 1987 were 16.6 and 15.1 kBq, respectively.     

Determination of99Tc-DPD complex composition and valence states of technetium

DPD (2,3-dicarboxypropane-1,1-diphosphonic acid) forms two complexes with⁹⁹Tc, previously reduced by Sn(II): with _max at 410 nm (pH 3–7), and at 515 nm (pH 5–9.6). By Job's method, formation of complexes with DPD:Tc molar ratios of 21 and 23 was found in acidic medium (pH=3). In order to determine the valence states of Tc in the complex, taking into account that formation of⁹⁹Tc-DPD complex does not occur in absence of a reducing agent (here divalent tin), the redox potentiometric titration method was applied. In acidic medium (pH=3), Tc was reduced to Tc(III) by Sn(II), while in presence of DPD to Tc(IV). In strongly alkaline medium (pH>13) the situation was reverse: Tc(III) was formed in the DPD complex, while Tc(IV) in absence of the ligand. In slightly alkaline medium (pH about 8) in both cases (with or without the ligand) TC(III) was obtained at the titration end point. This phenomenon can explain the dependence of^99mTc-radiopharmaceutical complexes on the sequence of reagent addition. These conclusions are very important for^99mTc-DPD radiopharmaceutical solutions used in diagnostic nuclear medicine for skeletal imaging.     

Separation of trace elements,In(III), Sn(IV), Sb(V) and Te(IV) by adsorption on activated carbon and graphite

Adsorption behaviour of trace elements, In(III), Sn(IV), Sb(V) and Te(IV) on activated carbon and graphite powder was studied. Adsorption characteristics of the ions enabled the separation of In(III)–Sn(IV), Sn(IV)–Sb(V) and Sb(V)–Te(IV) pairs. Applications to practical separation, milking of^113mIn from¹¹³Sn, removal of tin impurity from¹¹⁹Sb, and milking of¹¹⁹Sb from^119mTe, are presented.     

Statistical analysis of the results of99mTc-MDP quality control

The methods used for control of radiochemical purity of^99mTc-MDP are presented. TLC method on silica gel, developed with methanol and acetone (11 v/v), was convenient for determination of^99mTcO ₄ ^– with the content of 2.6±1.2%. The reliable results on detection of^99mTc hydrolyzate (2.2±1.3%) and for another^99mTc-MDP complex (13.2±2.8%) were obtained by application of ITLC (SA), developed with Sn-MDP. By Sephadex G-25 column chromatography (1.5 cm×5 cm) the separation of^99mTcO ₄ ^– was not achieved. The range of normal^99mTc-MDP biodistribution values in the organs of experimental animals have been determined. The mean value of bone distribution was 8.4±1.13%/g, in muscles 0.071±0.033%/g, while uptake in liver and kidneys was below 5%. Chi-square test and P show that the results on biodistribution of^99mTc-MDP in liver, bones and muscles are arranged around their mean values, which is statistically allowed.     

A study of the use of crystalline titania for cobalt fixation

A study of fixation of cobalt on the crystalline matrix of titania by co-precipitation was carried out. The tracer level solid-liquid distribution of⁶⁰Co over preformed hydrous titania showed an appreciable uptake of 71%. Macro amounts of Co²⁺ ions were precipitated along with Ti(IV) hydroxide (pH 8–9) and a maximum loading of 29 wt% was observed. The Soxhlet leachabilities of the calcined mixed mass, heated at 1000 °C, were found to be in the order of 10^–1 g·m^–2·d^–1 and the observation of structural changes of the original host matrix of titania revealed the fixation of cobalt in the mineral assemblage of CoTiO₃ (rhombohedral) and the rutile form of titania.     

Spectrophotometric and first-derivative spectrophotometric determination of cadmium witho-hydroxybenzenediazoaminoazobenzene (HDAA)

The synthesis ofo-hydroxybenzenediazoaminoazobenzene (HDAA) is described. Cadmium forms with HDAA in the presence of Triton X-100 a 13 complex, which gives a maximum absorption at 520nm with an apparent molar absorptivity of 1.97 × 10⁵1 · mol^–1 · cm^–1 in pH 10 borax buffer solution and 1.52 × 10⁵1 · mol^–1 · cm^–1 in ammoniacal medium. In both media, Beer's law is followed in the range of 0 –10 g of cadmium in 25ml of solution and the coefficients of variation do not exceed 1.5%. A derivative method has been employed to determine cadmium in certain waste water samples without separation.     

Spectrophotometric determination of nitrite in environmental waters using column preconcentration on biphenyl

Column preconcentration methods have been established for the spectrophotometric determination of trace nitrite with sulfanilic acid (SA) orp-aminoacetophenone (AAP) as the diazotizable aromatic amine andN, N-dimethylaniline (DMA) or 1-aminonaphthalene (AN) as the coupling agent, using differention-pairs co-precipitated with biphenyl. Nitrite ion reacts with SA in the pH range 2.0–3.0 and AAP in the pH range 1.7–3.0 in HCl medium to form water-soluble colourless diazonium cations. These cations are subsequently coupled with DMA in the pH range 3.7–6.1 for the SA-DMA system and AN in the pH range 1.7–2.3 for the AAP-AN system to be retained on microcrystalline biphenyl packed in a column. The solid mass is dissolved out from the column with 5 ml of DMF and the absorbance is measured by a spectrophotometer at 420 nm for the SA-DMA system and at 517 nm for the AAP-AN system. The calibration was linear over the concentration ranges 0.3–6.0 g of nitrite in 5 ml of DMF solution (i.e., 0.02–0.40 g/ml in the sample solution) for the SA-DMA system and 0.5–7.0 g of nitrite in 5 ml of DMF solution (i.e., 0.03–0.47 g/ml in the sample solution) for the AAP-AN system. The molar absorptivity and Sandell's sensitivity were respectively 2.63 × 10⁴lmol^–1cm^–1 and 1.75 × 10^–3 g cm^–2 for SA-DMA and 3.28 × 10⁴lmol^–1 cm^–1 and 1.40 × 10^–3 g cm^–2 for AAP-AN. The concentration factors were 4 and 16 for SA-DMA and AAP-AN, respectively. The detection limits were 0.0138 and 0.0175 g/ml NO₂ ^– for SA-DMA and AAP-AN, respectively. Seven replicate determinations of a solution containing 3.5 g of nitrite gave mean absorbances of 0.410 and 0.500 with relative standard deviations of 0.51 and 0.55% for SA-DMA and AAP-AN, respectively. Interference from various foreign ions has been studied and the methods have been applied to the determination of nitrite in environmental samples.     

Synthesis of195mPt radiolabelled cis-diamminedichloroplatinum/II/ of high chemical and radiochemical purity using high performance liquid chromatography

An improved method is described for the synthesis of^195mPt-radiolabelled cis-diamminedichloroplatinum/II. An amount of 10 mg of 95% enriched¹⁹⁴Pt was irradiated for 75 h in the hydraulic conveyer of the KUR at a thermal neutron flux of approximately 8.15×10¹³ n.cm^–2.sec^–1 and the^195mPt-radiolabelled CDDP was purified using HPLC. The chemical yield is 61% its chemical purity is greater than 99.74% the radiochemical purity is nearly 100%, and the specific activity is 7.4×10⁶ Bq mg^–1 CDDP/200 Ci mg^–1 CDDP/.     

Enrichment of sea-salt aerosols in short-lived222Rn daughter products-role of marine Fe/III/ hydroxide colloid

The interaction of short-lived Rn-daughter products /SLDP/, viz.²¹⁴Pb and²¹⁴Bi dissolved in sea-water with Fe/III/ hydroxide colloids followed by flotation of combined Fe-SLDP particles at the sea-air interface subsequently generating marine aerosols enriched in²¹⁴Bi and²¹⁴Pb have been studied under laboratory conditions. Rate constants for attachment of²¹⁴Bi and²¹⁴Pb to dispersed Fe/III/ colloids in the sea water are found to be 3.7×10^–4 min^–1 litre [g/Fe/]^–1 and 2.4×10^–4 min^–1 litre [g/Fe/]^–1, resp., /20°C/ over the concentration range of iron /III/ from 8 to 120 g liter^–1. The suggested mechanism of colloid flotation and aerosol generation might be responsible for some peculiarities of SLDP distribution in the lower marine atmosphere.     

Activity concentrations of238U and226Ra in agricultural samples

Distributions of²³⁸U and²²⁶Ra in agricultural samples and cultivated soils have been studied over ten years. The crops are rice, spinach and Chinese cabbage. Two investigated areas have been selected (35° 18 N, 113° 35 E). The agricultural samples and soils were collected annually from May 1982 through October 1991. The activity concentrations of²²⁶Ra in agricultural samples are greater than those of²³⁸U. The transfer factors of²³⁸U,²²⁶Ra are from 0.06·10^–3 to 1.2·10^–3. The²²⁶Ra/²³⁸U ratios for three agricultural samples have their characteristic values.     

Column preconcentration of gold by adsorbing AuCl<Stack><Subscript>4</Subscript><Superscript>−</Superscript></Stack> onto methyltrioctyl ammonium chloride–naphthalene and subsequent atomic absorption spectrometric determination

A sensitive, selective and simple preconcentration method for ultra-trace gold determination has been developed that uses naphthalene–methyltrioctyl ammonium chloride (Aliquat 336s) as an adsorbent. Gold, in the form of AuCl₄^–, was retained by the adsorbent in the column at a flow rate of 1 ml min^–1. After filtration, the solid mass consisting of the gold complex and naphthalene was dissolved out of the column with 5 ml of N,N-dimethylformamide (DMF), and the metal was then determined by atomic absorption spectrometry. In the initial solution, the calibration graph of absorbance versus gold concentration was found to be linear in the range 0.5–150 ng ml^–1 Au(III) with r=0.997 (n =9), and the 3 s detection limit was 0.428 ng ml^–1. The relative standard deviation for eight replicate measurements of 20 g of gold was 2.14%. Preconcentration factors of 390 and 650 were achieved using 5 ml and 3 ml of DMF, respectively. The proposed method was successfully applied to the determination of gold in wastewater, processed pool water, slurry pool water, and raw well-water from the Moteh gold mine, and synthetic samples.     

Extraction-chromatographic separation of137mBa from137Cs

The possibilities of extraction-chromatographic separation of^137mBa from¹³⁷Cs in genetic succession were studied, using columns filled with support beads loaded with the extractant H⁺[)–(3)–1,2–B₉C₂H₁₁]₂Co^–, further referred to as dicarbolide-H⁺, in nitrobenzene. The dependence of the amount of separable activities on experimental conditions was established. Optimal conditions were selected for the separation process. The effects of isotopic and nonisotopic carriers of^137mBa on the separation and the degree on saturation of extraction-chromatographic column with Ba²⁺ ions were evaluated. The effects of acidity of the elution solutions, of flow-through velocity, the amount of elution solution and the quality of carrier beads on the separation process were assessed. The extraction-chromatographic yield was calculated and the number of possible repeated elution cycles for^137mBa with saline and some other eluents was determined.     

Determination of239+240Pu in surface air in several localities in Czechoslovakia in 1986 in connection with the Chernobyl radiation accident

In connection with the radiation accident at the Chernobyl nuclear power plant, the concentration of^239+240Pu was determined in surface air at several localities of Czechoslovakia during the year 1986.^239+240Pu was found in the surface air in the period of April 29–May 5 in amounts ranging from 10 to 140 Bq.m^–3. In the period of June–December, 1986, the^239+240Pu concentration in the surface air was comparable with that before the Chernobyl radiation accident.     

Comprehensive Thermodynamic Model Applicable to Highly Acidic to Basic Conditions for Isosaccharinate Reactions with Ca(II) and Np(IV)

Isosaccharinate (ISA^–), a degradation product of cellulose codisposed in low-level nuclear wastes, is expected to be one of the dominant complexing ligands for radionuclides, especially tetravalent actinides. This paper presents a comprehensive thermodynamic model for isosaccharinate reactions with Ca(II) and Np(IV). The model is valid for a wide range of pH values (2–14), ISA^– concentrations (ranging up to 0.1 m), and ionic strengths (ranging up to 6.54 m), and is based on (1) NMR investigations of HISA(aq) (-D-isosaccharinic acid) and ISL(aq) [dehydration product of HISA(aq)], and the solubility of Ca(ISA)₂(c) as a function of pH and concentrations of Ca and ISA^–; (2) NpO₂(am) solubility in a wide range of pH values (2–14) and total ISA concentrations of 0.0016 and 0.008 m and at fixed pH values of approximately 5 and 12 with total ISA concentrations ranging from 0.0001 to 0.1 m; and (3) solvent extraction of Np-ISA solutions, containing fixed NaClO₄ concentrations ranging from 0.103 to 6.54 m and at fixed pC _H+ values ranging from 1.5 to 1.9, with dibenzoylmethane. Pitzer's ion-interaction approach was used to interpret the data. The different aqueous species required to explain these data included HISA(aq), ISL(aq), Ca(ISA)⁺, Np(OH)₃(ISA)(aq), Np(OH)₃(ISA)₂ ^–, Np(OH)₄(ISA)^–, and Np(OH)₄(ISA)₂ ^2–. The values of equilibrium constants for reactions involving these species and determined from these data provided close agreements between the observed and predicted concentrations in all of the systems investigated in this study and those reported previously.     

Spectrophotometric determination of 1-naphthylamine in urine with pentacyanonitrosylmanganate (II)

A new Spectrophotometric method is proposed for the determination of 1-naphthylamine (R), based on its reaction with Mn(CN)₅NO^2– to form Mn(CN)₅NH₂R^3– and measurement of the absorbance at 472 nm. In aqueous medium the molar absorptivity of the manganese complex is maximum ( = 8.0 × 10³1 · mole^–1 ·cm^–1) in the pH range 5.0–10.0, the colour develops more rapidly at pH 10.0. The absorptivity is increased by a factor of 3.5 if the complex is extracted as an ion-associate into chloroform. The extraction efficiency is 99.2% for a single-step extraction, and a concentration factor of 5 can also be achieved. Linearity of response extends over the range 0.04–1.4 gmg/ml 1-naphthylamine, the coefficient of variation being 1.4% at the 0.29 g/ml level (n = 6). The detection and determination limits are 0.005 and 0.018 g/ml, respectively. The method is selective enough to allow the determination of 1-naphthylamine in the presence of considerable amounts of other amines, such as aminophenols and phenylenediamines. Results obtained in the determination of 1-naphthylamine in human urine were very satisfactory.     

Determination of137Cs and134Cs in air samples collected near Belgrade /Yugoslavia/ following the Chernobyl accident

This paper presents the results of measurements of¹³⁷Cs and¹³⁴Cs content in air sampled during May 1986. Maximum concentrations:¹³⁷Cs 2.94±0.01 Bq m^–3 and¹³⁴Cs 1.38±0.01 Bq m^–3 were registered on May 3. Several other long lived radionuclides having -energies in the region 33 keV to 1365 keV were registered in the same samples two years later. The results of measurements of the total -activity in air for the same period are also presented.