Toxicity of boron to rainbow trout: a weight-of-the-evidence assessment.

From the large data set available on the toxicity of boron to aquatic organisms, the toxicity of boron to the early life stages of rainbow trout (Oncorhyncus mykiss) is the seminal issue relative to setting water quality criteria and effluent standards. Issues associated with the early life stage studies are the flat concentration-response curve, the low threshold of toxicity, and teratogenic effects observed. Recent laboratory and field studies offer new experimental data that make a weight-of-the-evidence assessment timely.

Carcinogenicity of halogenated olefinic and aliphatic hydrocarbons in mice.

A series of 15 halogenated hydrocarbons of industrial and environmental importance were tested for carcinogenicity by chronic administration by one or more routes in Ha:ICR Swiss mice. Not all compounds were tested by the four routes of administration used. Allyl chloride, 1,2-dibromo-3-chloropropane, and vinylidene chloride were active as skin tumor initiators in the two-stage carcinogenesis assays; phorbol myristate acetate was used as a promoter.

Mouse skin carcinogenicity tests of the flame retardants tris(2,3-dibromopropyl)phosphate, tetrakis(hydroxymethyl)phosphonium chloride, and polyvinyl bromide.

The flame retardants tris(2,3-dibromopropyl)phosphate, tetrakis(hydroxymethyl)phosphonium chloride, and polyvinyl bromide were tested for carcinogenic activity by skin application 3 times weekly in random-bred female ICR/Ha Swiss mice for 420 to 496 days. Tris(2,3-dibromopropyl)phosphate at two dose levels (30 mg and 10 mg/application) induced benign and malignant tumors of the skin, forestomach, and oral cavity (tongue and gingiva) in a statistically significant number of mice (30/group). A statistically significant incidence of papillary tumors of the lung was observed at both dosages, and the higher dose also resulted in one mouse with a tubular adenoma of the kidney.

Structure and tumor-promoting activity of analogues of anthralin (1,8-dihydroxy-9-anthrone).

Seventeen analogues of the tumor-promoting agent anthralin were tested for the same biological property by repeated skin application on mouse skin using female ICR/Ha Swiss mice, after a single application of a subcarcinogenic dose of 7,12-dimethylbenz[a]anthracene. Seven of the compounds tested are new compounds. They are 1,8-diacetoxy-9-anthrone, 1,8-dimyristoyloxy-9-anthrone, 1,8-dihydroxy-10-acetyl-9-anthrone, 1,8-dihydroxy-10-myristoyl-9-anthrone, 1,8,10-trihydroxy-9-anthrone, 1,8-dihydroxy-9,10-dihydroanthracene, and myristoyljuglone.

A new personal monitoring device for the detection of beta-propiolactone and other alkylating agents.

A personal monitoring badge has been developed for the detection of the direct-acting, alkylating carcinogen beta-propiolactone at atmospheric concentrations as low as 6 ppb for 24-hour and 0.6 ppm for 0.25-hour exposure.

Reaction of DNA with glycidaldehyde. Isolation and identification of a deoxyguanosine reaction product.

Glycidaldehyde, a bifunctional carcinogenic alkylating agent, has been found to react with calf thymus DNA in vitro under alkaline conditions. A product was isolated and identified to be the result of a fusion of a delta4-imidazoline ring to the pyrimidine ring of deoxyguanosine at the N-1 and 2-NH2 positions. Following reaction and dialysis, the DNA was hydrolyzed enzymatically to nucleosides.

Evaluation of chemical flame retardants for carcinogenic potential.

Tetrakis(hydroxymethyl)phosphonium chloride (THPC) and Pyroset TKP, which is the mixed acetate/phosphate of the same phosphonium base, are widely used in flame-retardant cotton fabrics, particularly in children's sleepwear. THPC degrades thermally and under certain chemical conditions to yield hydrochloric acid and formaldehyde (CH2O). In solution, the latter two compounds are in equilibrium with the known potent carcinogen bis(chloromethyl)ether (BCME).