Toxicity of benzotriazole and benzotriazole derivatives to three aquatic species.

Benzotriazole and its derivatives comprise an important class of corrosion inhibitors, typically used as trace additives in industrial chemical mixtures such as coolants, deicers, surface coatings, cutting fluids, and hydraulic fluids. Recent studies have shown that benzotriazole derivatives are a major component of aircraft deicing fluids (ADFs) responsible for toxicity to bacteria (Microtox). Our current research compared the toxicity of benzotriazole (BT), two methylbenzotriazole (MeBT) isomers, and butylbenzotriazole (BBT). Acute toxicity assays were used to model the response of three common test organisms: Microtox bacteria (Vibrio fischeri), fathead minnow (Pimephales promelas) and water flea (Ceriodaphnia dubia). The response of all the three organisms varied over two orders of magnitude among all compounds. Vibrio fischeri was more sensitive than either C. dubia or P. promelas to all the test materials, while C. dubia was less sensitive than P. promelas. The response of test organisms to unmethylated benzotriazole and 4-methylbenzotriazole was similar, whereas 5-methylbenzotriazole was more toxic than either of these two compounds. BBT was the most toxic benzotriazole derivative tested, inducing acute toxicity at a concentration of < or = 3.3 mg/l to all organisms.

Time dependent modifications in arterial flow in a transplanted pulmonary lobe.

Study of pulmonary arterial flow in the transplanted lung by means of an implanted ultrasonic flowmeter enables us: 1. To confirm results obtained by other methods (De Bono,8 Strider14 and Strandberg18): without specific treatment, rejection of graft causes increased peripheral resistances and the pulmonary arterial flow decreases progressively. 2. To prove by direct observation the existence in the treated animal of authentic precapillary shunts whose importance can cause the animal's death through functional disorder alone.