page 81 the annual dose resulting from the deposition of 1 kBq/m2 of CS137 is given at 1.2 milliSieverts (cumulative in the first year).
Tomio Kawata, a research fellow of the Nuclear Waste Management Organization of Japan is quoted saying "While the expected radiation exposure from 1.48 million becquerels of cesium is around five millisieverts a year, below the government’s benchmark of 20 millisieverts for evacuation orders, decontamination will still be necessary before evacuees can return as radioactive cesium binds strongly to soil, making it hard to reduce radiation levels, Kawata said."
My question is: by applying Petrangeli "ground shine" conversion factor 1.48 million Bequerels should result in 1,480*1.2 Millisieverts or something about a staggering 1.7 Sieverts of accumulted exposition over just the first year.
what I am missing ? where is the error ?