MaterialSpecific ActivityA2 Quantity
natural uranium26 Bq/mg 0.7 Ci per
ton (Metric)
Unlimited
Some other isotopes of interest:
americium 241 0.13 TBq/g 3.4 Ci/g 0.0054 Ci 1.6 mg
iodine 131 4.6 TBq/mg 120 Ci/mg 13.5 Ci 11 mg
thallium 201 7.9 TBq/mg 210 Ci/mg 270 Ci 1.3 mg
cobalt 60 42 TBq/g 1.1 Ci/mg 10.8 Ci 10 mg
carbon 14
in natural air
0.04 Bq/liter
0.03 Bq/g
1 pCi/liter 54 Ci
(2 TBq)
50 km^3 Ci
( The p prefix is 10^-12 and the T prefix means 10^12)