Final answer:
The PHN will want to monitor cases of cancer and genetic defects as these are the two known long-term effects of radiation exposure.
Step-by-step explanation:
The PHN (Public Health Nurse) sent to the site of a nuclear accident will want to monitor cases of cancer and genetic defects. These are the two known long-term effects of radiation exposure. High doses of radiation have been shown to increase the risk of cancer, and radiation can also cause genetic defects.