Dynamics of reconstructed instrumental data for the 131I specific activity within the Brinow bis community in the Warsaw milk producing area: 1 – instrumental data; 2 – exponential interpolation; 3 – perennial lawn grass, direct calculation; 4 – cultivated pasture grass, reconstruction; 5 – annual greens, reconstruction; 6 – perennial greens, reconstruction; 7 – sown annual grass for green fodder, reconstruction; 8 – rainfall intensity.