Peitou Stone emits a small amount of radiation, and during the occupation the Japanese saw it as a "natural memento," and thus granted Peitou Creek a degree of protection while developing the area. Even today, since Peitou Stone is still formed there, the riverbanks are protected in their natural state and may not be banked up with cement as at other sites.
北投石具有微量的鐳放射能，早在日據時代就被視為「天然紀念物」，日人還因此對北投溪展開一定程度的保護，也是因為北投石的存在，才使得今天的北投溪還能維持天然的河岸，不被水泥所取代。