set of measurements, $^{137}$Cs, had an uncertainty of 6.4%. To achieve a volume similar to the food samples analyzed, 53.5 grams of the river sediment was thoroughly mixed with 141.7 grams of flour and counted in the same geometry.

The results of the food sampling are shown in [**Table \[tab:fukushimafood\]**]{}. In most of the Pacific Fish samples, $^{137}$Cs was present, with the highest activity found in tuna from the Philippines, which had a $^{137}$Cs activity of 0.24(4) Bq kg$^{-1}$. No samples had a detectable presence of $^{134}$Cs, which would have indicated that Fukushima products were present. Therefore, without $^{134}$Cs, the detected $^{137}$Cs is attributed to legacy activities such as surface nuclear weapons testing. It is also worth noting, that all samples had much higher levels $^{40}$K present, which is a naturally-occurring isotope. Comparing $^{137}$Cs to $^{40}$K is useful, since they both belong to the same column on the periodic table, and hence have similar affinities in various tissues and minerals. The tuna from the Phillipines for instance, had a $^{40}$K activity of 105(3) Bq kg$^{-1}$ – more than four hundred times the activity of the $^{137}$Cs. Comparisons such as this are useful in evaluating the relative danger the $^{137}$Cs presents 