To investigate if the interactive effects (enhanced teratogenicity) noted for radiofrequency irradiation and 2-methoxyethanol (see publication 3519, publication 3522, publication 2234, and publication 9062) are unique to these agents, or if another solvent would interact with radiofrequency irradiation or 2-methoxyethanol. Because salicyl acid is widely used as an analgesic and is teratogenic in animals, the authors selected salicylic acid as a chemical to address generalizability.
Salicylic acid was administered on gestation day 9 or 13 to groups of rats. Dams treated on day 9 were given salicylic acid and exposed to radiofrequency irradiation sufficient to maintain colonic temperature at 41°C for 60 minutes. Those treated on day 13 were given salicylic acid plus 2-methoxyethanol. Dams were sacrificed on gestation day 20.
|Chamber||Near field synthesizer facilities operated in dominant electric field mode which were enclosed within copper screen wire chamber.|
|Setup||Animals were exposed without anesthesia in cylindrical plexiglas animal holders which prevented the animals from changing their orientation. The long axis of the animal was parallel to incident electric field.|
The findings provide no evidence of synergistic interactions between radiofrequency irradiation and salicyl acid. Limited evidence of antagonism was found between 2-methoxyethanol and salicylic acid (fetal weights).
This study highlights the importance of additional research on interactions in developmental toxicology. It emphasizes the need to consider combined exposure effects when developing both physical agent and chemical agent exposure guidelines.