According to the report by IAEA [1], the Chornobyl Nuclear Power Plant (CNPP) accident deposited above 1480 kBq/m^2 in the nearby area (‘nearby’ on the small map scale). I saw another map on Twitter (@AlanAbdo13) that showed the ground contamination level at the location where the Russian army dug the trenches close to the plant was >18500 kBq/m^2 (Cs-137) (on a much larger map scale). I couldn’t confirm the map source, but it is believable according to the exponential scale of the IAEA map.
Map source: United Nations Scientific Committee on the Effects of Atomic Radiation and World Health Organization, 2008. Chernobyl: Looking back to go forward. Proceedings of an international conference. Publisher: IAEA (Fig. 1).
Now, let’s make some comparisons.
Fukushima.
Among the soil samples that I collected in a Fukushima forest in the evacuation zone (then), about 35 km northwest of the Fukushima Daiichi Nuclear Power Plant (FDNPP), the highest contamination level was 1,525 kBq/m^2 in the surface soil (0-2 cm) (2017). If I totaled 0-30 cm depth, the highest was 4310 kBq/m^2 (2017).
The highest air dose rate observed in the same forest was 3.7 µSv/h (2018). The air dose rate in the no-return zone, about 5 km from the FDNPP, was 8.0-9.0 µSv/h (2018).
The ground.
If the ground contamination level of the soils where the soldiers stayed was 1480 Bq/m^2, probably it was not life-threatening for a short stay in trenches or above the ground. If it was >18500 kBq/m^2, that was more than four times that of the Fukushima forest soils with the highest contamination I observed.
The air.
I was unable to find the current and verified air dose rates in the Red Forest area. A Twitter account reported 11 µSv/h at the edge of the Red Forest (@fpleitgenCNN) today (April 8, 2022). That is a little aove the observation in the Fukushima no-return zone.
However, according to a journal article [2], the highest air dose rate ‘inside the forest’ was about 300 µGy/h (=350 µSv/h) in 2000. A couple of websites [3-5] list the air dose rates in the forest, which vary at 0.1-10 mSv/h (=100-10,000 µSv/h).
The US NRC regulation says that radiation workers may receive up to 5 rems (5000 mrem) per year=5000 mrem/8760 hours=0.57 mrem/h=5.7 µSv/h.
Even if we use 300 µSv/h as a conservative estaimate, the air dose rates in the Red Forest could be as much as 53 times higher than the US NRC regulation.
What about the direct radiation the soldiers were receiving in the trenches, surrounded by the highly contaminated soils? It is different from walking on the surface where the air flows freely.
Other factors.
There are other factors. Were they drinking water from streams? Did they cut down trees and burn them for fire? Did they sleep on the ground, not using mats? Did they catch animals and eat them?
Whatever the answers are to these unknowns, a positive outcome cannot be expected from this level of exposure.
References
United Nations Scientific Committee on the Effects of Atomic Radiation and World Health Organization, 2008. Chernobyl: Looking back to go forward. Proceedings of an international conference.
Chesser, R.K., Bondarkov, M., Baker, R.J., Wickliffe, J.K. and Rodgers, B.E., 2004. Reconstruction of radioactive plume characteristics along Chernobyl’s Western Trace. Journal of environmental radioactivity, 71(2), pp.147-157.
THE RED FOREST: THE MOST RADIOACTIVE OUTDOOR ENVIRONMENT ON THE PLANET (https://chernobylx.com/the-red-forest-the-most-radioactive-outdoor-environment-on-the-planet/)
Mapping the Red Forest (https://www.neimagazine.com/features/featuremapping-the-red-forest-7331935/)
THE RED FOREST AND THE BRIDGE OF DEATH IN CHERNOBYL ARE THE MOST ICONIC LOCATIONS OF THE ZONE (https://trips-to-chernobyl.com/en/the-red-forest-and-the-bridge-of-death-in-chernobyl-are-the-most-iconic-locations-of-the-zone/)