Comparative inhalation toxicity of technical chlordane in rats and monkeys

Abstract

Technical chlordane (1,2,4,5,6,7,8,8‐octachloro‐3a, 4,7,7‐tetrahydro‐4,7‐methanoindane) is used extensively for control of certain wood‐boring insects. The present study was conducted to evaluate the inhalation toxicity of technical chlordane in rats and monkeys. Range‐finding (28‐d) and subchronic (90‐d) inhalation studies with Wistar rats, and subchronic (90‐d) inhalation studies with cynomolgus monkeys were conducted. In the range‐finding study in rats, the threshold of toxicity for technical chlordane was approximately 5.8 μg/1. Among the observations made during the course of the 90‐d study, in which technical chlordane was administered by inhalation to rats and monkeys at concentrations close to 0.1, 1.0, and 10 μg/l, the most significant were associated with alterations in the liver and were confined to rats only. However, in the rat, the effects on the liver were largely reversible during 90 d following cessation of administration of technical chlordane. The no‐effect level of chlordane inhalation in rats appears to be between 0.1 and 1.0 μg/l, while in monkeys the no‐effect level is in excess of 10 μg/l. This study demonstrated that the monkey, a species closely related to humans, can tolerate relatively high chlordane concentrations without any adverse effects.