Abstract
The importance of understanding the effects of radiation exposure on wildlife is a critical responsibility of our stewardship of nuclear energy production. We tested the hypothesis that songbirds respond to exogenous radiation exposure with changes in plasma 8-hydroxy-2'-deoxyguanosine (8-OH-dG). We exposed two species of songbirds, house sparrows (Passer domesticus; n = 12) and song sparrows (Melospiza melodia; n = 12), to one of four acute whole-body radiation treatments: 75, 150, 300, or 600 mGy. We measured DNA damage by proxy as 8-OH-dG levels in the plasma at 0 hr (baseline), 36 hr, and 7 days post radiation. For both species, at all radiation treatments, 8-OH-dG levels increased significantly 36 hr following radiation exposure. However, songbird species differed significantly in response to treatment across time and between treatment groups. Song sparrows showed no significant changes in 8-OH-dG levels between 36 hr and Day 7. In contrast, house sparrows exposed to 300 and 600 mGy had significantly increased 8-OH-dG levels at Day 7 compared with 36 hr. This study demonstrates that in a controlled experiment, in isolation from other sources of genotoxicity, radiation exposure significantly affects songbirds. Our results suggest future research examining the effects of radiation on songbirds must consider using multiple species to assess the biological effects of radiation, as different species can show strikingly different responses to radiation dosage across time.