River       Sample_ID              Sample_type                         Collection_method               Location_notes         Latitude      Longitude       Date_Collected  Ra228_s  Ra228_s_error  Ra226_s  Ra226_s_error  ratio_228_to_226  
Kolyma      Kolyma Sediment (1)    Bulk Sediment                       nd                              Kolyma main channel    68.965318     161.547775      2018-07-30      2.05     0.3            1.45     0.07           1.4               
Kolyma      Kolyma Sediment (1)    Desorbed from sediment              experimentally determined       nd                     nd            nd              nd              0.39     0.05           0.33     0.01           1.2               
Kolyma      Kolyma Sediment (2)    Bulk Sediment                       nd                              Mouth of Kolyma        69.621753     162.124557      2018-07-30      2.10     0.15           1.70     0.06           1.2               
Kolyma      Kolyma Sediment (2)    Desorbed from sediment              experimentally determined       nd                     nd            nd              nd              0.29     0.04           0.20     0.01           1.4               
Buskin      Buskin Sediment        Bulk Suspended Sediment             1 um Hytrex cartridge filter    Buskin River           57.75616      -152.4836       2019-09-08      0.7      nd             0.2      nd             3.5               
Buskin      Buskin Sediment        Desorbed from suspended sediment    experimental results            nd                     nd            nd              nd              0.1      0.02           0        0.01           nd                
Susitna     Susitna Sediment       Bulk Suspended Sediment             1 um Hytrex cartridge filter    Susitna River          61.7214154    -150.2070422    2019-09-10      0.6      nd             0.6      nd             1.0               
Susitna     Susitna Sediment       Desorbed from suspended sediment    experimental results            nd                     nd            nd              nd              0.1      0.03           0.1      0.01           1.0               
Matanusk    Matanuska Sediment     Bulk Suspended Sediment             1 um Hytrex cartridge filter    Matanusk River         61.501252     -149.2508464    2019-09-10      1.8      nd             1.8      nd             1.0               
Matanusk    Matanuska Sediment     Desorbed from suspended sediment    experimental results            nd                     nd            nd              nd              0.07     0.02           0.1      0.01           0.7               
Knik        Knik Sediment          Bulk Suspended Sediment             1 um Hytrex cartridge filter    Knik River             61.4832632    -149.2514167    2019-09-10      0.9      nd             0.6      nd             1.5               
Knik        Knik Sediment          Desorbed from suspended sediment    experimental results            nd                     nd            nd              nd              0.2      0.03           0.1      0.01           2.0