A review on speciation of iodine-129 in the environmental and biological samples.

As a long-lived beta-emitting radioisotope of iodine, (129)I is produced both naturally and as a result of human nuclear activities. At present time, the main part of (129)I in the environment originates from the human nuclear activity, especially the releases from the spent nuclear fuel reprocessing plants, the (129)I/(127)I ratios have being reached to values of 10(-10) to 10(-4) in the environment from 10(-12) in the pre-nuclear era. In this article, we review the occurrence, sources, inventory, and concentration level of (129)I in environment and the method for speciation analysis of (129)I in the environment. Measurement techniques for the determination of (129)I are presented and compared. An overview of applications of (129)I speciation in various scientific disciplines such as radiation protection, waste depository, and environmental sciences is given. In addition, the bioavailability and radiation toxicity (dose to thyroid) of (129)I are discussed.