Also, the Greenpeace statement mentions fires, which are a far far better explanation for a spike in measurements. https://www.greenpeace.org/international/press-release/54762...
They also have pictures and mention the Russian camp was at "Stantzaya Yanov" which i cant find a reference to outside of the Greenpeace report. But i would suspect that wouldnt be directly in front of the very visible sarcophagus.
edit: Maps in the report https://www.greenpeace.de/publikationen/20220718-greenpeace-... Page 6 says the camp was 26km from the plant.
edit1: Estimates from https://essd.copernicus.org/articles/10/339/2018/
https://essd.copernicus.org/articles/10/339/2018/essd-10-339... with longitude and latitude and Greenpeace puts the camp at 51.1663, 29.9645 SSW of the reactor. Which would put it in a safe area. Meaning they were right to be not worried if the trenches were at the camp.
edit2: It being the byproduct of Russian navigation efforts is quite a compelling explanation. https://www.reuters.com/world/europe/unprotected-russian-sol...