INTERACTIONS OF RADIOFREQUENCY RADIATION-INDUCED HYPERTHERMIA AND 2-METHOXYETHANOL TERATOGENICITY IN RATS

Radiofrequency (RF) radiation is used in a variety of workplaces. In a ddition to RF radiation, many workers are concurrently exposed to nume rous chemicals; exposed workers include those involved with the microe lectronics industry, plastic sealers, and electrosurgical units. The d evelopmental toxicity of RF radiation is associated with the degree an d duration of hyperthermia induced by the exposure. Previous animal re search indicates that hyperthermia induced by an elevation in ambient temperature can potentiate the toxicity and teratogenicity of some che mical agents. We previously demonstrated that combined exposure to RF radiation (10 MHz) and the industrial solvent, 2-methoxyethanol (2ME), produces enhanced teratogenicity in rats. The purpose of the present research is to determine the effects of varying the degree and duratio n of hyperthermia induced by RF radiation (sufficient to maintain colo nic temperatures at control [38.5], 39.0, 40.0, or 41.0 degrees C for up to 6 h) and 2ME (100 mg/kg) administered on gestation day 13 of rat s. Focusing on characterizing the dose-response pattern of interaction s, this research seeks to determine the lowest interactive effect leve l. Day 20 fetuses were examined for external and skeletal malformation s. The results are consistent with previous observations. Significant interactions were observed between 2ME and RF radiation sufficient to maintain colonic temperatures at 41 degrees C for 1 h, but no consiste nt interactions were seen at lower temperatures even with longer durat ions. These data indicate that combined exposure effects should be con sidered when developing both RF radiation and chemical exposure guidel ines and intervention strategies. (C) 1997 Wiley-Liss, Inc.