Low-solubility chromates, such as lead chromate, zinc chromate and calcium chromate, which are potent carcinogens, have been examined for their solubility and clastogenic effects in a cultured Chinese hamster cell line (Don) as compared with those of potassium chromate, which is a high-solubility chromate and a weak carcinogen. Lead chromate was slightly soluble in water, Tyrode's solution, protein or amino acid solution, fetal calf serum and culture medium. Zinc chromate and calcium chromate were less soluble in serum and Tyrode's solution than in water. There were good correlations between the frequencies of chromosomal aberrations in the cells treated with the above chromates and chromium concentrations dissolved from these chromates in culture medium. When the frequency of chromosomal aberration in the cells exposed to the above chromates was compared on equal amounts of dissolved chromium concentrations in culture medium, the frequency of chromosomal aberration was the most remarkable with lead chromate, followed by zinc chromate and potassium chromate and then by calcium chromate. On the column chromatographs by gel filtration on Sephadex G-200, the chromium dissolved from all the above chromates in culture medium was present with low molecular fraction. From the above results, it was assumed that the carcinogenicity of low-solubility chromates might be related to their low solubility in body fluid.
There are many kinds of fumes containing heavy metals in the working area. They sometimes have bad effects on the living body. It is important to determine their particle size distribution for considering the effects of those metals on health, together with measuring their amounts. For this purpose, it is neces-sary to generate fumes which are suitable to use. However, effective methods for generating fumes of heavy metals with high melting points have not been developed. In this study we attempted to determine whether the plasma flame metal sprayer can be used as a fume generator. The size distribution, particle form and amounts of the generated fumes were determined for the iron fume which were generated with this instrument under the various conditions. The fume was to consist of coagulated fine particles and dispersed globular particles. Our attempt extended to the generation of fumes consisting not only of one kind of metal but also of two kinds of metal. It was also found that fumes having the required radio might be generated by controlling the ratio of the metals in the powder mixture. We conclude that this instrument might be suitable for generating fumes of heavy metals in the laboratory.
A two-component fluidized bed aerosol generator was designed to generate fibrous aerosol. A fiber feeder was attached to the fluidized bed. Fibrous glass was fed to the fluidized bed at feed rates ranging from 1 mg/min to 50 mg/min. In order to change the feed rate, a periodical feed method was developed and examined as an operating mode of the fiber feeder. The generator was normally operated continuously for two hours and for eight hours at most. The aerosol mass output of this generator was usually 0.8 mg/min. More than 10% of the fed fibrous glass was aerosolized by the generator. The size distributions of fiber length and diameter did not change with time, but the con-centration of the aerosol increased slightly at the rate of 10%/hour.
The use of quality control samples of blood and urine into trays was done upon the basis of the micro-sampling method of Delves for rapid screening determinations of lead in blood and urine by Atomic Absorption Spectrophotometry. For lead in urine this was extended over a range of 12.66 μmol Pb 1-1 from patients under chelation therapy usually EDTA-Ca without any interference. Thirty-six urine samples with lead concentrations ranging from 0.08 to 12.66 μmol Pb 1-1 were analysed by colorimetry involving the use of dithiozone. A correlation coefficient of 0.9992 with a 0.995 level of conficence was found. The sensitivity of the method is 0.14 μmol Pb 1-1 per 1 per cent absorption at 283.3 nm with the lowest limit of detection of 0.20 μmol Pb 1-1. In a collaborative test study for blood lead shows that there is a good agreement in interlaboratory variation, and intralaboratory variation. In our intralaboratory experiences we have noted that the mean values are closer to the mean values given for all participants from U.K. External Quality Assessment Scheme (UKEQAS). Considerations were made about precision and accuracy by using two types of absorption tubes as well as the effect of oxidation samples procedures.
Cadmium acetate exposure revealed lung lesions by a single i.t. injec-tion (8.0 mg Cd/Kg) ; and adrenal and spleen lesions by a single i.p. injection(6.0 mg Cd/Kg) in male laboratory-bred squirrels after different intervals of the week-long study. The squirrels after i.t. injection did not show any pathological change in adrenal and spleen. However, lung showed emphysematous changes and peribronchiolar infiltratation by inflammatory cells. On the other hand, the i.p. injection did not reveal any of the changes in lung. But, the outer cortex of adrenal showed minimal fatty change and haemorrhage in medulla. Spleen revealed congestion in the pulp, thickening of the capsular wall and the infiltration of lymphocytes just below the capsular wall. Afer 7 days, i.t. and control groups increased by 1.14 and 1.15 folds in body weight, whereas, i.p. showed augmentative effect by 1.01 folds. The results suggest that i.p. injection is more toxic than i.t. injection as evident from the bodyweight.