137Cs concentration in soil of the Municipality of Guadalupe, Zacatecas, Mexico, before and after the Fukushima Daiichi nuclear power plant accident

This paper presents the assessment of the 137 Cs concentrations in the soil of the municipality of Guadalupe, Zacatecas, Mexico, recorded during two sampling periods, in April 2008 and September 2011. The main objective of this work is to present reference values in the region of interest before and after the catastrophic accident which occurred on 11 March 2011 at Japan’s Fukushima Daiichi nuclear power plant. The average activity concentration values are lower than the world average of 51 Bq kg −1 . The 137 Cs concentration in the soil of the Guadalupe region therefore does not represent a radiation risk to the population; furthermore, there is not enough evidence to conclude that the concentration levels of 137 Cs increased after the nuclear accident.