Germán Orizaola
Researcher at the Joint Institute for Biodiversity Research of the University of Oviedo
This is a descriptive study of the population structure of feral dogs in the Chernobyl Exclusion Zone. The study is interesting to learn about the population dynamics of Chernobyl dogs, but since its design does not include any estimation of radiation exposure or other environmental factors, it is not possible to estimate from this work any effect of radiation exposure on any of the parameters studied. The article has very little to do with the press release with which they want to promote it [in the press release the genetic changes are attributed to exposure to different doses of radiation].
The study must be understood as a study of population dynamics in small feral populations, fundamentally disconnected from other similar populations due to the scarce presence of humans (and therefore dogs) around them. A large part of the results presented can be explained by the fact that the Chernobyl dog population is a population that originates from a rather small number of individuals and because it is still quite isolated from similar populations.
The study presents good quality in its genetic analyses, but since it does not include any data reflecting radiation exposure in the individuals studied, its conclusions cannot go beyond the analysis of the dynamics of a feral vertebrate population. It would be the equivalent of studying the structure and interconnectedness of stray cat populations in Madrid.
It brings the novelty of studying the interconnection between the different groups of dogs in the area, which could provide information for their possible management. By not studying in any way any parameters in relation to the levels of radiation that these dogs may have experienced throughout their lives, it is not possible to conclude anything about the possible changes that may have occurred as a result of exposure to radiation.
It is important to note that the study was conducted between 2017 and 2019, when radiation levels in the Area have been reduced by more than 90% since the time of the accident, and the isotopes most harmful to living organisms, such as I-131 have been gone for decades.
To put the study in perspective, one of the large groups of dogs studied, that of the city of Chernobyl, is currently in an environment with radiation levels equivalent to those that can be found naturally in the Iberian Peninsula. Today all the measuring stations in the city of Chernobyl register less than 0.25 microSv/h, values that are found naturally in large areas of the central and northwestern part of the Peninsula.
From my point of view there are many limitations to consider the study as relevant from the point of view of the effects of radioactive contamination on living organisms. The main one, that radiation exposure is not measured in any of the individuals studied, and therefore makes the study uninteresting, as such, from a radiological point of view.
A worrying aspect is the fact that the authors do not seem to distinguish between the initial effects of the accident and the current situation, more than three decades later with a radical change in radiation levels and the identity of the radioactive substances. The article insists that the accident generated "an ecological catastrophe of massive proportions" and "that many species have not recovered from the consequences of the catastrophe" (without providing data to support these assertions), ignoring the works that indicate that at present the Chernobyl Exclusion Zone is one of the largest natural reserves in Europe, an example of passive renaturation processes, and with clear and abundant examples of species with notable population increases.