摘要:

Two hundred and twenty-seven samples of wheat, forty soils, and four plants of theAstragalusfamily, all from the province of Alberta, have been analysed for their selenium content. The selenium content of the soils varied from less than 0.1 to 1 p.p.m., that of wheat, from less than 0.1 to 1 p.p.m., and that ofAstragalusplants, from 0.3 p.p.m. in the root of one plant to 600 p.p.m. in the stalks of another. The majority of the wheat samples contained only traces of selenium, and in no case can any one be considered as dangerous. Some of the soils contained over 0.5 p.p.m. of selenium and these may be looked upon as seleniferous. Not enough data are available to indicate the extensiveness of seleniferous soils. Although the underlying strata of much of Alberta is of Upper Cretaceous Age, the soil is derived mostly from glacial drift formed from other types of rock, so that the seleniferous area may be much smaller than that earlier suspected. Analyses of wheat and soils indicate that dangerous areas are more likely to be found in southern Alberta than in central Alberta. Analyses of vetches show that the amount of selenium absorbed is independent of the species and the selenium content of the soil and varies with the part of the plant examined.

ISSN:1923-4287    

DOI:10.1139/cjr41b-025

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

A study was made of the precipitation, at room temperature, of the carbonates of cadmium, cobalt, and nickel, of the chromate of beryllium, of the borates of zinc, of the silicates of copper and of the arsenates of lead. A rapid-mixing apparatus that insured that the precipitations took place in homogeneous liquid medium was used. In each series of experiments, the concentration of one reacting solution was kept constant and that of the other systematically varied. The values of the molar ratio of oxides, CdO/CO2for example, in the precipitates were found by analysis. If they remained constant with different concentrations of reactants, a definite compound was indicated. The normal cadmium carbonate was obtained. Three definite basic compounds, not described in the literature, were prepared: a definite basic carbonate of cobalt, 5CoCO3∙Co(OH)2, and two definite basic arsenates of lead, 4Pb3(AsO4)2∙Pb(OH)2and 9Pb3(AsO4)2∙Pb(OH)2. Dilead arsenate, PbHAsO4, was easily precipitated, but trilead arsenate, Pb3(AsO4)2, only under very specific conditions. The other precipitates were all mixtures. The influence of the hydrogen ion concentration of the solutions on the composition of the precipitates formed was deter

ISSN:1923-4287    

DOI:10.1139/cjr41b-026

出版商:NRC Research Press    

年代:1941

数据来源: NRC