Air sampling and analysis in a rubber vulcanization area.

Results of sampling and analysis of air in a rubber vulcanization area are described. Organic compounds were collected on activated charcoal, desorbed with carbon disulfide and analyzed by gas chromatography. Several previously identified substances were quantitated, including styrene, toluene, ethylbenzene, and several oligomers of 1,3-butadiene. Concentrations ranged from 0.007 to 1.1 ppm.

[Experimental study of chloroprene for carcinogenicity]. / Eksperimental'noe izuchenie khloroprena na kantserogennost'.

Chloroprene (2-chlorobutidiene 1,3) is an intermediate chemical product derived in the process of obtaining synthetic rubber. Chloroprene was shown by the experiments on mice and rats to be not carcinogenic. The application of chloroprene in animals by skin smears, subcutaneous injections, per os and intratracheal administration failed to induce any tumors in the experimental animals. No tumors were observed also in animals after using its combination with very small doses of dimethylbenz (a) anthracene.

Hepato-and cardiotoxicity of xanthoascin, a new xanthocillin analogue produced by Aspergillus candidus. II. A preliminary electron microscopic observation of the heart and lung with intranuclear myelin-like figures.

Xanthoascin (1-4(hydroxyphenyl)-4-(2,2-dimethyl-6-chromanyl)-2,3-diisocyano-1,3-butadiene), a toxic metabolite recently isolated from rice grains infested with Aspergillus candidus L., caused acute hepatic injury with jaundice in mice. Following this, if the animals survived, degeneration of the myocardium developed over several weeks. Myocardial cells of dilated ventricular walls were diffusely vacuolated in routine H.E. sections. Electron microscopically, the vacuoles were filled with osmiophilic, concentric lamellar figures of varied size. Judging from observations in the early stages, this structure seems to develop in relation to mitochondrial membrane. The nuclei of the interstitial cells of the myocardium and pulmonary alveoli contained similar myelin-like figures. Recently it has been found that most strains of A. candidus produce terphenyllin, another toxic compound, and a smaller number of them produces, in addition to terphenyllin, xanthoascin. This may indicate that xanthoascin can be a candidate as a causative agent of primary myocardial diseases of men and contamination of foods with A. candidus and xanthoascin should be eargently examined.

Aspects of the toxicology of chloroprene: immediate and long-term effects.

The maximum permissible concentration (MPC) of chloroprene was set at 2 mg/m3 in the USSR in the 1940's. The existing MPC is 4 mg/m3. The threshold of systemic effects as a result of chronic chloroprene exposure is l.69 mg/m3. However, the threshold for embryotoxic and mutagenic effects is 0.15 mg/m3. In consideration of this information, setting a new MPC for chloroprene at 0.05 mg/m3 is recommended.

Hepato- and cardiotoxicity of xanthoascin, a new metabolite of A. candidus Link, to mice. I. Blood chemistry and histological changes in mice.

Aspergillus candidus Link, one of the commonest constituents of cereal mycoflora, produces two kinds of mycotoxins, terphenyllin and xanthoascin, which show different chemical and toxicological properties. The latter, xanthoascin, caused severe hepatic injury with jaundice and focal or confluent necrosis of hepatocytes, when given to mice in doses of 6 mg/kg b.w. or higher by a single subcutaneous injection. With higher doses above 15 mg/kg, myocardial degeneration and necrosis was induced after a week or two in addition to the hepatic injury. Vacuolation of the nuclei of the alveolar interstitial cells of the lung and myocardial interstitial cells was another characteristic lesion caused by this mycotoxin. Other organs including the testicles and thymus were widely involved. The unique nature of lesions in the liver and heart may necessitate further investigations in the field of mycotoxicology in relation to human diseases such as nutritional hepatitis and primary myocardial degeneration.

Measurement of some potentially hazardous materials in the atmosphere of rubber factories.

Two separate topics of work are outlined: methods for the measurement of chlorinated monomers in PVC and polychloroprene, and also methods for the measurement of these materials in factory air. Typical results which have been obtained in supplies of raw materials, in finished products, and in the working atmosphere at manufacturing operations are given. The second topic concerns the measurement of benzo[a]pyrene in the atmosphere of a tire manufacturing plant. This material is present in trace quantities in the mineral oils and carbon blacks used by the industry. The atmospheric concentrations present at various processes in this plant were measured on a daily basis over a period of two years, and the results obtained compared with results taken concurrently from an outside air station. It is shown that no significant quantities of benzo[a]pyrene are produced by tire manufacturing operations.

Determination of hexachloro-1,3-butadiene in spinach, eggs, fish, and milk by electron capture gas-liquid chromatography.

Hexachloro-1,3-butadiene (HCBD), a waste product formed in the manufacture of perchloroethylene and trichloroethylene, has been found in fish from the lower Mississippi River basin. The AOAC official method for organochlorine pesticide residues in fatty and nonfatty foods has been modified for the determination of HCBD residues in selected food commodities. Acetonitrile extracts of nonfatty foods, or the combined acetonitrile extracts obtained in acetonitrile-petroleum ether partitioning of fat isolated from fatty foods, are diluted with water and extracted with petroleum ether. The petroleum ether extracts are chromatographed on Florisil and HCBD is eluted with petroleum ether. The elute is analyzed by gas-liquid chromatography with an electron capture detector. Average recoveries of HCBD from fortified samples of fatty and nonfatty foods were greater than 90% in the interlaboratory trials of the method.

Toxicological studies of photosensitizer agents and photodegradable polyolefins.

The authors report the results of a series of toxicological tests conducted on plastic materials (polyethylene) activated with tetraphenylbutadiene (TPB) an additive recently proposed as a sensitizer capable of photodegrading plastic materials. The toxic effects of polyethylene, TPB, and TPB's degradation products were investigated in rabbits, mice and rats. The studies revealed these products to possess a very low toxicity.