A North Korean nuclear test will cause serious radioactive damage to the Korean Peninsula.

Radio Free Asia on Thursday said that since the North is a small nation with a high population density, the mountainous area in Hamgyeong Province is a possible test site.

It warned that an underground nuclear test in the North will destroy the eco-system and contaminate drinking water.

Since most of the peninsula's rivers originate from mountains, experts say nuclear tests there will contaminate water for drinking, irrigation and industrial use over a long period.