The most recent compilation of release estimates to the air and sea including ongoing releases can be found in this report.
http://www.fukuleaks.org/web/?p=11668
We found a drastic difference between estimate ranges across academic and official agency reports and papers. Both the wide range of release estimates and the levels of the high end estimates show a need for more research and ongoing analysis of the air and sea to fully understand what is happening.
Older initial source term estimates below
Source Iodine & Cesium Source Term
TEPCO • 6×1016 Bq I-131 & 7×1015 Bq of Cs-137
NSC • 1.5×1017 Bq of I-131 & 1.2×1016 Bq of Cs-137
NISA • 2.7×1017 Bq of I-131 & 1.3×1016 Bq of Cs-137
ZAMG • 4×1017 Bq of I-131 & 3.3×1016Bq of Cs-137
Cazzoli • 3.8×1017 Bq of I-131 & 1.3×1017 Bq of Cs-137
IRSN • 4.08×1017 Bq of I-131 & 5.4×1016 Bq of Cs-137
Stohl et al. • (no iodine estimate) & 3.66 ×1016 Bq of Cs-137
Chornobyl • 1.8×1018 Bq of I-131 & 8.5×1016 Bq of Cs-137
Unit 4 SFP, Cazzoli • 9×1016 Bq Iodine-131 & 3×1016 Bq Cesium-137 (NOTE: independently qualifies as INES Level 7)
Worst Case • 3.4×1018 Bq of I-131 (2×Chornobyl) & 8.5×1017 Bq of Cs – 137