High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! Uranium in the environment refers to the science of the sources, environmental behaviour and effects of actinides in Earth's environment and in animals (including humans). This page is a subpage of actinides in the environment. Uranium is a naturally occurring element found in low levels within all rock, soil, and water. This is the highest-numbered element to be found naturally in significant quantities on earth. According to the United Nations the normal concentration of uranium in soil is 300 g kg 1 to 11.7 mg kg 1.