Posted on Dec 19, 2012, 6 a.m.
Variation in low-level, natural background radiation may exert a small, but highly statistically significant, negative effects on DNA as well as several measures of health.
Even the very lowest levels of radiation are harmful to life. Reporting the results of a wide-ranging analysis of 46 peer-reviewed studies published over the past 40 years, researchers from the University of South Carolina (South Carolina, USA) and the University of Paris-Sud (France) found that variation in low-level, natural background radiation may exert a small, but highly statistically significant, negative effects on DNA as well as several measures of health. The review is a meta-analysis of studies of locations around the globe that have very high natural background radiation as a result of the minerals in the ground there, including Ramsar, Iran, Mombasa, Kenya, Lodeve, France, and Yangjiang, China. Timothy Mousseau and Anders Moller examined over 5,000 papers involving natural background radiation that were narrowed to 46 for quantitative comparison. The selected studies all examined both a control group and a more highly irradiated population and quantified the size of the radiation levels for each. Each paper also reported test statistics that allowed direct comparison between the studies. The organisms studied included plants and animals, but had a large preponderance of human subjects. Each study examined one or more possible effects of radiation, such as DNA damage measured in the lab, prevalence of a disease such as Down's Syndrome, or the sex ratio produced in offspring. For each effect, a statistical algorithm was used to generate a single value, the effect size, which could be compared across all the studies. The researchers reported significant negative effects in a range of categories, including immunology, physiology, mutation and disease occurrence, with the frequency of negative effects was beyond that of random chance. Reporting that: “Susceptibility to radiation varied among taxa, and several studies provided evidence of differences in susceptibility among populations or strains,” the study authors conclude that: “These studies suggest that current levels of natural radioactivity may affect mutational input and thereby the genetic constitution and composition of natural populations. “
Moller AP, Mousseau TA. “The effects of natural variation in background radioactivity on humans, animals and other organisms.” Biol Rev Camb Philos Soc. 2012 Nov 8.