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The results of a series of inter-laboratory cross-check on the determinations of ppb and sub-ppb levels of copper and lead in environmental samples are described. Thirteen laboratories participated during a five-stage comparison. Seven analytical methods and two pre-concentration procedures were performed on certified and real samples. For controlled and blind standards at higher concentration levels (10 ppb or above) the data reported by different participants show good agreement for both elements regardless of the method chosen. However, for samples having lower concentrations (1-10 ppb level), the relative standard deviation (R.S.D.) and bias increased. A high degree of scattering on data were demonstrated for a deep ocean water at less than 1 ppb level. The results of the present study give direct comparison between different analytical methods, and also reflect the average aptitude of analytical laboratories in Taiwan on the measurements of copper and lead in environmental samples.

Mossbauer isomer shifts of 119Sn in a series of complexes K2Sn(OH)6-mFm observed at 78 K were −0.05, −0.05, −0.24, −0.27 and −0.40 mm s−1, respectively, for m=0, 2, 4, 5 and 6. These IS values were linearly related to both m and (the average Pauling electronegativity of the ligands): . The IS straight line was compatible within experimental error with the one reported by Parish and Row-botham for the hexahalogenostannate complexes SnX4Y22, namely, The revised IS straight line including both series of complexes could be expressed by the equation Quadrupole splittings observed in the complexes of m = 2,4 and 5 were 1.16, 0.80 and 0.73 mm s−1 respectively. They were linearly related to both m and .

Isomer shift of simple lines of the frozen mixture solutions of SnCl5H2O and K2SnF6 were linearly related to mole fraction and, therefore, to average ligand number, n. These spectra corresponded to Sn(H2O)6-nFn(- n)+. Assuming that quadrupole splitting was also linearly related to n, Mossbauer spectra of Sn(ClO4)2 solutions containing different amount of HF could be resolved into components.

Mossbauer parameters of frozen salt solutions could be correlated with apparent degree of dissociation, γ. KSnCl3 and KSnBr3 were dissolved in 0.5 M H2SO4, whereas NH4 SnCl3 was dissolved in 0.5 M HClO4. Mossbauer studies were made at different concentrations.

Stability constants of fluorostannate(II) complexes were determined Mossbauer spectroscopically by rapid freezing technique. The observed isomer shift values suggested that these complexes were hydrogen bonded in perchloric acid solutions.

Mossbauer parameters of frozen aqueous solutions of Sn(ClO4)2 in 0.5 M HClO4 did not change with the concentration of NaClO4, so that it was used to keep the ionic strength at the desired level. When NaCl was added into Sn(ClO4)2 solutions, isomer shift did not change, but quadrupole splitting did. Therefore, stability constants were calculated from the quadrupole splitting data, which were in good agreement with the published values. The observed spectra could be resolved into components.

The contents of Br and I in commercial sodium glutamate and cassava flour were determined by neutron activation analsis at the Tsing Hua Reactor. The conventional carbon tetrachloride extraction method was employed for the analysis of these elements. It was found that the content of Br varied widely between 0.003 and 0.1 ppm, while that of I varied between 0.06 and 0.7 ppm, in six samples of sodium glutamate. Two samples of cassava flour were found to contain 0.1 and 0.2 ppm of Br, and 0.02 and 0.04 ppm. of I, respectively. The higher contents of these elements in come glutamate samples as compared with the raw material was considered to be the contamination from chemicals used in the production processes.

The sorption of radiocesium (Cs-134) by seven different samples of soil has been studied over a wide pH range (0–14). In general, the sorption is excellent except in the low pH region. The presence of 0.01 N Na +, Mg++, Ca++, Sr++, Ba++ and Al+++ does not seem to influence either the uptake of radiocesium by, or the extraction of the sorbed radiocesium from, Red soil and Yellow soil.

Trace impurities in aluminum were determined. Manganese, nickel, copper, cobalt and iron were analyzed by the metod of activation analysis at the THOR, while sodium and potassium were determined by flame photometry. The results were: Mn 0.00066%, Ni 0.00041%, Cu 0.00060%, Co 0.00010%, Fe 0.12% and Na 0.0048%. K was not detected by flame photometry.

Thorium nitrate was conductometrically titrated with malonic, succinic, adipic acids in aqueous solutions and azeleic and sebacic acids in alcoholic solutions, respectively. The composition and electrolytic behavior of thorium-malonate system were investigated by conductometric and pH measurements. The formation of Th(CH2(COO)2)2 was observed in the conductometric titrations of thorium nitrate with sodium and ammonium malonates, while that of the complex ion, (Th(OOC.CH2.-COO)4)−4, in the reverse titrations. The approximate solubility product constant of the former is estimated from the results of pH measurements.

The removal of Sr-90 by various clay deposits at pH values ranging from 0 to 14 shows slightly less effective than radiocesium uptake. The radiostrontium uptake by Red and Yellow soil is greatly affected by the foreign cations (0.01 N). Yellow soil is particularly suited for the removal of Sr-90.

Separation factors for La, Ce, and Pr were measured precisely on columns of bis(2-ethylhexyl) orthophosphoric acid (DEP) supported on diatomaceous silica made hydrophobic with dimethyldicltlorosilane. Column behavior is related to the properties of DEP when used as a solvent extractart, and the column method is a useful one for studying a solvent extraction system with great precision and reproducibility. Separation factors measured are Ce/ La = 2.8 plus or minus 0.1 and Pr/Ce = 2.7 plus or minus 0.1. The dependence of elution volume on HCl activity was found to be approximately 2.5 power in the range 0.2--0.3 M HCl. (auth)

Radioactive constituents and equllibria in the hot spring sediment Hokutolite were studied by determination of the activity ratio of U series to Th series. Investigation of natural radioactivity of the Hokutolite was examined in three portions, i.e., the Pb portion, Bi portion, and hydroxide portion. The various nuclides present in different portions were identified by following the growth and decay curves of the radioactivity of each portion. These three portions of Hokutolite were separated by either of two outlined procedures. For quantitative study the radioactive elements of the U series were determined by the absolute counting of Bi/sup 210/ and that of the Th series by absolute counting of AC/sup 228/. Since the BETA -ray energies of Ac/sup 228/ and Bi/sup 210/ ar e almost the same (1.11 and 1.17 Mev respectively), activities of both nuclides were determined by the constant geometry method, using Bi/sup 210/ as the reference source for BETA rays. Activities of the Bi and hydroxide portions were measured in hydroxide form. By analyzing the timeactivity curves it was possible to calculate the activity of Bi/sup 212/ at time (T) = 0 to be approximates 150 cpm (if Bi/sup 212/ is not separated from Pb/sup 212/ atmore » T = 0) and the saturation activity of Bi/sup 210/ is about 390 cpm. Since the half life of Pb/sup 210/ is very long (11 yr), the saturation activity of Bi/sup 210/ would be about the same as that of Pb/sup 210/ at T = 0, if it were not separated from Pb/sup 210/. Therefore, the apparent activity ratio of U series to Th series is 380/150 = 2.5. In the hydroxide pontio the activity decayed with a half life of 6 hr to zero, and no other activity growth was observed afterwards. The only radioactive nuclide with a half life of 6 hr is Ac/sup 228/, which enables determination of the activity of Th series by the simple determination of Ac/sup 228/. In the Bi portion the analysis of the decay curve showed that it is composed of two sup 212/ and Bi/sup 210/ must be present. The activity of Bi/sup 210/ at T = 0 was obtained by extrapolation of the analyzed decay curve of Bi/sup 210/. Quantitative analysis of M/sub 2/O/sub 3/ from the hydroxide portion showed that the M/sub 2/O/sub 3/ content is 2.56%; thus, there is 78.8 mg of M/ sub 2/O/sub 3/ in 3 g of Hokutolite. Similarly, the Ra/sup 228/ content is 0.16 x 10/sup -13/ g/g Hokutolite. Since the activity of the hydroxide portion decayed in a simple fashion with a half life of 6 hr, and no other activity growth was observed, U and Th are absent from Hokutolite. Otherwise the activities due to U and Th together with their daughters should be observed in the hydroxide pontion. Thus, it is concluded that there are no equilibria between U/sup 238/ and Ra/sup 226/ between U/sup 235/ and Ra/sup 223/, or between Th/sup 232/ and Ra/su p 228/. The radioactive equilibrium originates from Ra, as is supported by the presence of Ac/sup 228/ the daughter of Ra/sup 228/. Since the radioactive series in Hokutolite originates from Ra, the presence of Ra/sup 226/(1822 yr), Ra/sup 228/(8.7 yr), and Ra/sup 223/(11.1 days) can be predicted. Since Ra/sup 228/ has a very short half life as compared with the history of the formation of Hokutolite, it is believed that if there had been any Ac series in hot spring water and in Hokutolite, their activity would have been exhausted in Hokutolite. (BBB)« less

Radioactive minerals other than Hokutolite and monazite are unknown up to present in Taiwan. The hard green copperiferrous quartz found in north Taitung and collected by two field survey teams, exhibited measurable activity, the origin of which was found to be uranium. Activation analysis revealed that the content of uranium in these samples ranged between 0.002 and 0.035%. It was also found that uranium was accompanied with copper, and that inclusion of iron in the sample decreased the uranium content. The result will be of value in the understanding of the cause of concentration of uranium in quartz and its physical and chemical state in these samples. The content of uranium in talc and monazite concentrate was also determined.

The method of Winchester(2) for the determination of potassium by nondestructive activation analysis has been applied to the determination of soil potassium. The experiments with seven soil samples of known potassium content gave good results. However, large discrepencies that existed between the nondestructive method and the flame photometry were shown by another set of twelve samples to be due to the statistical error in the activity measurements.

The removal of radiouropium (Eu-152, 4) is practically complete at the pH values greater than 4 by the seven clay deposits studied. The chemical properties of the radioeuropium rather than the nature of the sorbing matrices are the determining factor in its decontamination. The effect of competition toward radioeuropium uptake from solutions by, and extraction of sorbed radioeuropium from, Yellow and Red soil by various cations (0.01N) have been studied.