The natural radionuclides (238U, 226Ra, 232Th and 40K) content of different kind of Egyptian kaolin has been determined by a gamma ray spectroscopy system using a high purity germanium detector. Twenty Kaoline samples were collected from four different areas (Tushka, kalabsha, El-Esila and ElShallal). Radium equivalent, gamma radioactivity level index, radiation exposure rates and radiation doses were measured due to external exposure to the kaoline gamma ray. Excess life time cancer risk (ELCR) was calculated. Total excess life time cancer risk (ELCR) was found to be high due to high natural radioactivity concentrations in different areas which represent radiological risk for the health of the population. The activity ratios between thorium to uranium concentration for all samples were calculated (232Th/238U) clark's value.

In this work, the activity concentration of radon 222Rn, radon emanation factor, radon mass exhalation rate and annual effective dose from radon in these locations of kaolin samples were calculated.

This study reveals in general that all samples are exceeding the world permissible safe criteria and consider a risk source for human environment.