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824. Tests for toxic metals
THE CHEMICAL ENVIRONMENT
535
(Cited in F.C.T. 1964, 2, 240), is widely used as a solvent in the dye industry, cases of industrial poisoning by I are practically unknown. However, this paper reports a case of acute poisoning in an industrial worker who had taken a few breaths of I which had escaped from a container. The toxic effects included chronic asthmatic bronchitis and a diffuse severe fatty infiltration of the liver. The conclusion was drawn that I is as toxic as the chemically-related ethylenemonochloro- and ethylenedichlorohydrins. 823. The fate of injected hydrazine Dambrauskus, T. & Cornish, H. H. (1964). The distribution, metabolism, and excretion of hydrazine in rat and mouse. Toxic. appl. Pharmac. 6, 653). Following the production of hydrazine hydrate on a tonnage scale by the Germans in World War II for use as a rocket and jet fuel, hydrazine (I) and its derivatives are now used extensively in many industrial processes including the production of fuel, explosives, photographic materials, chemiluminescent materials, insecticides, plastics, dyes, pharmaceuticals and solder flux. The toxicity of I has been studied to a limited extent and the dermatitis produced by derivatives of I was referred to previously (Cited in F.C.T. 1964, 2, 757). The distribution in rats, and metabolism and excretion in mice was followed after subcutaneous injections of I. In mice, approximately 50% of doses of 40 and 60 mg I/kg was excreted unchanged in the urine within 48 hr. The rapid disappearance of about 50% of I within 0.5-2 hr after injection, which could not be accounted for in the urine or carcass of mice within 2-48 hr, suggested that the chemically-reactive I was bound to tissue components, and that when these binding sites became saturated the remaining unbound I was excreted. Tissue distribution studies in rats 2 and 20 hr after a subcutaneous injection of 60 mg I/kg indicated a rather uniform distribution with the exception of the kidneys where high concentrations of I were found and of the body fat and brain which contained comparatively small quantities of I. After 20 hr, 27% of I had been excreted and only 1.5% remained as free or reactive I in the tissues. Diacetylhydrazine, a known urinary detoxication product of I, was not detected in the urine or tissues of both species by the present authors. 824. Tests for toxic metals Barker, J. H., Chapman, W. B. & Harrison, A. J. (1964). Toxic metals in school materials and toys. J. Ass. publ. Analysts 2, 89. Much attention has been paid recently in the national press to the problems associated with the occasional presence of toxic metals, particularly lead, in paints and children's toys. Not least among the problems is the difficulty of devising adequate tests for the extractability of heavy metals from plastics, since the potential danger depends not on the total quantity of the metallic compound present in the toy but on the amount which might come out if the product were chewed, sucked or even swallowed by a child. Efforts are therefore being directed towards the development of test procedures which would simulate the conditions that toys may encounter in the mouths of small children. This paper suggests methods for determining the amount of harmful metals in paint films, cores of pencils and crayons, plasticine, chalks and plastics. While test solutions of paint films and pencil cores are prepared by direct ashing followed by dissolution of the residue in acid, this method is obviously unsuitable as an indication of the amount of lead or other metal which might be extracted from plastics. The authors have therefore selected an extraction procedure for plastics materials consisting of successive treatments with alcoholic potash and nitric acid, evaporation of the extracts to dryness and dissolution of
536
THE CHEMICAL ENVIRONMENT
the residue in hydrochloric acid. Solutions prepared in this way, and by the direct ashing procedure, can be used for the estimation of arsenic, antimony, barium, cadmium, chromium and lead. Although this extraction procedure for plastics does not simulate natural conditions, it is thought to be at least as rigorous as any likely to occur during chewing or ingestion. No experimental work, however, has been carried out to confirm this assumption. 825. What some metals can do Schroeder, H. A., Balassa, J. J. & Vinton, W. H., Jr. (1964). Chromium, lead, cadmium, nickel and titanium in mice: Effect on mortality, tumors and tissue levels. J. Nutr. 83, 239. This is a continuation of previous work by Schroeder which reported the effects of small doses of chromium (Cr), lead (Pb), cadmium (Cd), nickel (Ni) and titanium (Ti) in the drinking water on the growth and survival of rats and mice (Cited in F.C.T. 1964, 2, 104 & 105). This report deals with the effects of lifetime administration of these five elements by the same route (5 pp'm in the drinking water) on 700 mice fed diets deficient in Cd and low in other metals. The intake of each metal was such that the resulting tissue concentrations were of the same order as those found in man. In this way toxicity assessment in man was made less hazardous. Although the mortality of females was unaffected, this was increased in the males on Pb, Cd and Ni (compared with Cr) and in those on Pb and Cd, when compared with the controls. None of these metals was carcinogenic. Body weights at death were greater in the groups on Cr, Pb and Ti than in those on Cd and Ni. Large increments of Ti, moderate increments of Cd and Ni and smaller increments of Cr and Pb, when compared with the controls, were found in the kidneys, liver, heart, lungs and spleen, the only organs analysed. There was no tissue accumulation with increasing age. It was concluded that all metals except Cr showed one or more signs of innate toxicity.
826. Loss of mercury by volatilization Magos, L., Tuffery, A. A. & Clarkson, T. W. (1964). Volatilization of mercury by bacteria. Br. J. ind. Med. 21, 294. Exposure to mercury (Hg) from various industrial processes (Cited in F.C.T. 1964, 2, 117 & 649; ihid 1965, 3, 120) is usually monitored by determining the concentration of Hg in the urine. Marked variations in the urinary concentrations of Hg in workers exposed equally to this industrial hazard have been reported. The present study indicates that some of these discrepancies can probably be attributed to the loss of Hg volatilization from infected urine samples. A chance observation indicated that tissue homogenates containing added mercuric chloride labelled with 2°3Hg lost radioactivity more rapidly than could be accounted for by the normal radioactive decay of this isotope. Volatilization of Hg has now been observed from tissue homogenates (amounting in one case to as much as 75% in 24 hr), infusion broth, plasma and urine containing labelled mercuric chloride. Micro-organisms have been implicated since rates of volatilization were extremely variable, a latent period usually preceded volatilization. Toluene inhibited this loss and the capacity to volatilize Hg could be transferred from one biological medium to another. In addition, two species of bacteria isolated and cultured from such homogenates and two other species isolated from the local water supply were able to volatilize Hg. These findings emphasize the importance of sterilizing urine samples that are collected for analysis of Hg, a precaution that is not normally taken. 827. Cellular changes produced by thallium Truhaut, R. (1964). Sur les propri~t~s antimitotiques des sels de thallium monovalents et leur signification toxicologique. Arzneimittel-Forsch. 14, 837.
535
(Cited in F.C.T. 1964, 2, 240), is widely used as a solvent in the dye industry, cases of industrial poisoning by I are practically unknown. However, this paper reports a case of acute poisoning in an industrial worker who had taken a few breaths of I which had escaped from a container. The toxic effects included chronic asthmatic bronchitis and a diffuse severe fatty infiltration of the liver. The conclusion was drawn that I is as toxic as the chemically-related ethylenemonochloro- and ethylenedichlorohydrins. 823. The fate of injected hydrazine Dambrauskus, T. & Cornish, H. H. (1964). The distribution, metabolism, and excretion of hydrazine in rat and mouse. Toxic. appl. Pharmac. 6, 653). Following the production of hydrazine hydrate on a tonnage scale by the Germans in World War II for use as a rocket and jet fuel, hydrazine (I) and its derivatives are now used extensively in many industrial processes including the production of fuel, explosives, photographic materials, chemiluminescent materials, insecticides, plastics, dyes, pharmaceuticals and solder flux. The toxicity of I has been studied to a limited extent and the dermatitis produced by derivatives of I was referred to previously (Cited in F.C.T. 1964, 2, 757). The distribution in rats, and metabolism and excretion in mice was followed after subcutaneous injections of I. In mice, approximately 50% of doses of 40 and 60 mg I/kg was excreted unchanged in the urine within 48 hr. The rapid disappearance of about 50% of I within 0.5-2 hr after injection, which could not be accounted for in the urine or carcass of mice within 2-48 hr, suggested that the chemically-reactive I was bound to tissue components, and that when these binding sites became saturated the remaining unbound I was excreted. Tissue distribution studies in rats 2 and 20 hr after a subcutaneous injection of 60 mg I/kg indicated a rather uniform distribution with the exception of the kidneys where high concentrations of I were found and of the body fat and brain which contained comparatively small quantities of I. After 20 hr, 27% of I had been excreted and only 1.5% remained as free or reactive I in the tissues. Diacetylhydrazine, a known urinary detoxication product of I, was not detected in the urine or tissues of both species by the present authors. 824. Tests for toxic metals Barker, J. H., Chapman, W. B. & Harrison, A. J. (1964). Toxic metals in school materials and toys. J. Ass. publ. Analysts 2, 89. Much attention has been paid recently in the national press to the problems associated with the occasional presence of toxic metals, particularly lead, in paints and children's toys. Not least among the problems is the difficulty of devising adequate tests for the extractability of heavy metals from plastics, since the potential danger depends not on the total quantity of the metallic compound present in the toy but on the amount which might come out if the product were chewed, sucked or even swallowed by a child. Efforts are therefore being directed towards the development of test procedures which would simulate the conditions that toys may encounter in the mouths of small children. This paper suggests methods for determining the amount of harmful metals in paint films, cores of pencils and crayons, plasticine, chalks and plastics. While test solutions of paint films and pencil cores are prepared by direct ashing followed by dissolution of the residue in acid, this method is obviously unsuitable as an indication of the amount of lead or other metal which might be extracted from plastics. The authors have therefore selected an extraction procedure for plastics materials consisting of successive treatments with alcoholic potash and nitric acid, evaporation of the extracts to dryness and dissolution of
536
THE CHEMICAL ENVIRONMENT
the residue in hydrochloric acid. Solutions prepared in this way, and by the direct ashing procedure, can be used for the estimation of arsenic, antimony, barium, cadmium, chromium and lead. Although this extraction procedure for plastics does not simulate natural conditions, it is thought to be at least as rigorous as any likely to occur during chewing or ingestion. No experimental work, however, has been carried out to confirm this assumption. 825. What some metals can do Schroeder, H. A., Balassa, J. J. & Vinton, W. H., Jr. (1964). Chromium, lead, cadmium, nickel and titanium in mice: Effect on mortality, tumors and tissue levels. J. Nutr. 83, 239. This is a continuation of previous work by Schroeder which reported the effects of small doses of chromium (Cr), lead (Pb), cadmium (Cd), nickel (Ni) and titanium (Ti) in the drinking water on the growth and survival of rats and mice (Cited in F.C.T. 1964, 2, 104 & 105). This report deals with the effects of lifetime administration of these five elements by the same route (5 pp'm in the drinking water) on 700 mice fed diets deficient in Cd and low in other metals. The intake of each metal was such that the resulting tissue concentrations were of the same order as those found in man. In this way toxicity assessment in man was made less hazardous. Although the mortality of females was unaffected, this was increased in the males on Pb, Cd and Ni (compared with Cr) and in those on Pb and Cd, when compared with the controls. None of these metals was carcinogenic. Body weights at death were greater in the groups on Cr, Pb and Ti than in those on Cd and Ni. Large increments of Ti, moderate increments of Cd and Ni and smaller increments of Cr and Pb, when compared with the controls, were found in the kidneys, liver, heart, lungs and spleen, the only organs analysed. There was no tissue accumulation with increasing age. It was concluded that all metals except Cr showed one or more signs of innate toxicity.
826. Loss of mercury by volatilization Magos, L., Tuffery, A. A. & Clarkson, T. W. (1964). Volatilization of mercury by bacteria. Br. J. ind. Med. 21, 294. Exposure to mercury (Hg) from various industrial processes (Cited in F.C.T. 1964, 2, 117 & 649; ihid 1965, 3, 120) is usually monitored by determining the concentration of Hg in the urine. Marked variations in the urinary concentrations of Hg in workers exposed equally to this industrial hazard have been reported. The present study indicates that some of these discrepancies can probably be attributed to the loss of Hg volatilization from infected urine samples. A chance observation indicated that tissue homogenates containing added mercuric chloride labelled with 2°3Hg lost radioactivity more rapidly than could be accounted for by the normal radioactive decay of this isotope. Volatilization of Hg has now been observed from tissue homogenates (amounting in one case to as much as 75% in 24 hr), infusion broth, plasma and urine containing labelled mercuric chloride. Micro-organisms have been implicated since rates of volatilization were extremely variable, a latent period usually preceded volatilization. Toluene inhibited this loss and the capacity to volatilize Hg could be transferred from one biological medium to another. In addition, two species of bacteria isolated and cultured from such homogenates and two other species isolated from the local water supply were able to volatilize Hg. These findings emphasize the importance of sterilizing urine samples that are collected for analysis of Hg, a precaution that is not normally taken. 827. Cellular changes produced by thallium Truhaut, R. (1964). Sur les propri~t~s antimitotiques des sels de thallium monovalents et leur signification toxicologique. Arzneimittel-Forsch. 14, 837.