Table 3. Lymphocyte metaphases analyzed by M-FISH in mice exposed to low doses of tritium in drinking water and to external γ-irradiation for 1 or 8 months.
| Treatment group | No of mice | No of metaphases | No of chromosome breakpoints |
|---|---|---|---|
| 1 month | |||
| Control | 6 | 509 | 9 |
| HTO 10 kBq/L | 3 | 254 | 4 |
| HTO 1 MBq/L | 3 | 260 | 9 |
| HTO 20 MBq/L | 2 | 206 | 8 |
| OBT 10 kBq/L | 3 | 259 | 6 |
| OBT 1 MBq/L | 5 | 586 | 16 |
| OBT 20 MBq/L | 4 | 252 | 10 |
| Gamma 1.44 μGy/h | 3 | 268 | 7 |
| Gamma 31.0 μGy/h | 3 | 248 | 2 |
| 8 months | |||
| Control | 4 | 408 | 5 |
| HTO 10 kBq/L | 2 | 301 | 1 |
| HTO 1 MBq/L | 2 | 382 | 0 |
| HTO 20 MBq/L | 5 | 533 | 7 |
| OBT 10 kBq/L | 3 | 299 | 6 |
| OBT 1 MBq/L | 6 | 475 | 15 |
| OBT 20 MBq/L | 4 | 466 | 20 |
| Gamma 1.44 μGy/h | 4 | 403 | 0 |
| Gamma 31.0 μGy/h | NA | NA | NA |
NA: Not available.