Comparison of cellular and whole-animal bioassays for estimation of radiation effects in the polychaete worm Neanthes arenaceodentata (Polychaeta).

The polychaete worm Neanthes arenaceodentata was used in experiments to determine possible relationships between short-term genotoxicity tests and reproductive and lethal consequences of exposure to ionizing radiation. Groups of juvenile N. arenaceodentata received one of four different radiation doses (2, 4, 8, and 16 Gy) to determine dose-effect estimates for chromosomal aberration induction, and groups of both adult and juveniles received one of seven different radiation doses (1, 4, 8.4, 46, 102, 500, and 1000 Gy) to determine dose-effect estimates for reproduction, mortality, and life span. Effects on reproduction and genetic material were observed at the lowest doses and in the same range; detrimental reproductive effects were observed at 1 to 4 Gy, and the frequency of chromosomal aberrations was significantly increased at 2 Gy. Only high doses resulted in acute mortality (greater than 500 Gy) and decreased life span (greater than 100 Gy). Dose-effect estimates for chromosomal aberration induction were dependent on radiation dose and on the stage of the cell cycle at the time of irradiation. Dose-effect estimates for reproduction were dependent on dose and the potential for repopulation of gonadal tissue. It is concluded that short-term genotoxicity test can be predictive of detrimental reproductive effects in those model systems for which basic cell kinetics and reproductive parameters are well known.