Interactive developmental toxicity of radiofrequency radiation and 2-methoxyethanol in rats.
Nelson-BK; Conover-DL; Shaw-PB; Werren-DM; Edwards-RM; Hoberman-AM
Teratology 1994 Oct; 50(4):275-293
A study was conducted to characterize the extent of synergism between radiofrequency (RF) radiation and 2-methoxyethanol (109864) (2ME) in rats and estimate the likelihood that the interactive effects of the two agents would be observed in humans at occupationally relevant exposures. Various combinations of RF radiation and/or 2ME were administered to groups of mated female Sprague-Dawley-rats on gestation days nine or 13. Colonic temperature was monitored in rats subjected to RF radiation only at a frequency of 10 megahertz and maintained at 42 degrees-C for up to 30 minutes. On gestational day 20 the animals were killed and examined for external, skeletal, and visceral malformations. Fetuses were removed and analyzed for malformations. Data were subjected to statistical analysis by Z-tests and the GEE approach. Synergism was noted between RF radiation and 2ME for only some treatment combinations. Day nine exposures generally indicated little effect from 2ME exposure, either by itself or combined with RF radiation. Day 13 exposures resulted in highly significant effects from 2ME and from RF radiation. Strong evidence was found of effects from both 2ME and RF radiation after exposure on day 13. These effects were noted in the forepaw digits, forepaw phalanges, hindpaw digits, hindpaw phalanges, hind limbs, metacarpals, and metatarsals. No global synergistic effect was noted, but evidence was noted for a synergistic effect at intermediate levels of the dose ranges. The authors suggest that the threshold for interactive effects falls below 75mg/kg, and cite further topics of research on the synergy between RF radiation and 2ME.
NIOSH-Author; Laboratory-animals; Reproductive-effects; Skeletal-system-disorders; Electromagnetic-radiation; Teratogenesis; Cytotoxic-effects
B. K. Nelson, Division of Biomedical and Behavioral Science, NIOSH C-24, Cincinnati, OH 45226