OBT- speciation dynamics as viewed from biochemistry F Baumgartner OBT Speciation by the Germany BIOCHEM Model Franz Baumgärtner Institut für Radiochemie Technische Universität Munich
The BIOCHEM model assumes that OBT = X + C B ound T ritium = XBT buried + CBT X = N,O,S buried = non-accessible by the rinsing solvent This OBT definition contradicts the common opinion: OBT = C arbon B ound T ritium = CBT (a biological product) caused by photosynthesis or incorporation Test of BIOCHEM aspects by analysis of OBT formation
In order to identify biological growth the fact is used: “ biological growth is composed of a I. Self-Accelerating Phase (Brody 1945, 1964) and a II. Self-Inhibiting Phase (Brody 1945,1964) A A A Thus, OBT = A*(1-2 –(t-to)/ τ ) OBT = A*(1-2 –(t-to)/ τ ) = A – C*2 t/ τ = A – C*2 t/ τ Biological formation contains Product Product Product Phase I and Phase II But, OBT = B*2 t/ τ OBT = B*2 t/ τ Mono-molecular reactions like isotope- exchange follow the same course Formation Time Formation Time Formation Time Therefore, No difference in the course of XBT- and CBT- formation
Fundamental differences in XBT- and CBT-formation rate XBT CBT is formed from HTO by T + T Cationic Tritium Anionic Tritium the movement of cationic or anionic tritium is without atomic shell inclusive atomic shell species mobility is like electrons like atoms (mass related) (mass related) very fast reaction rate conventional reaction rate
TEST OF NON ‐ BIOLOGICAL OBT FORMATION = OBT FORMATION WITHOUT PHASE I Tomato plants, 9 weeks exposed to atmospheric HTO 40.000 (F.S.Spencer 1984: ONTARIO HYDRO 84 ‐ 69 ‐ K) 35.000 30.000 OBT dynamics of Abrupt start of 6.000 6.000 6.000 6.000 25.000 HTO exposure OBT [pCi/gH] 20.000 5.000 5.000 5.000 5.000 15.000 4.000 4.000 4.000 4.000 10.000 Mechanism of TFWT[pCi/mL] TFWT[pCi/mL] OBT[pCi/gH] OBT[pCi/gH] OBT formation 5.000 3.000 3.000 3.000 3.000 recognized at 7d 14d 35d 42d 49d 56d 63d 21d 28d the very beginning 0 OBT, TFWT form 0 168 336 504 672 840 1008117613441512 2.000 2.000 2.000 2.000 Hours HTO Exposure synchroneously 1.000 1.000 1.000 1.000 early OBT = XBT buried because of no accelerating phase 0 0 0 0 0 0 24 24 48 48 72 72 Hours HTO Exposure Hours HTO Exposure
Consequences of the rapid triton mobility: Early OBT window and a Late OBT window Molecular visualisation of the early window : formation of proteins (we consider the case Ribonuclease) ms ms Aminoacids Peptide chain Secondary ms Quartenary Structures H + / T + µ s HTO µ s multi ms Ribonuclease T1, Arni R, Heinemann U,Tokuoka R, Saenger W, 1988 Ribonuclease T1, Takahashi K,1985
Molecular visualisation of the late window : H + migration into proteins case Ribonuclease) Similar in polysaccharides, cellulose, starch HTO weeks months years
The XBT buried fraction in tomato OBT 40.000 chronic HTO exposure 35.000 2 x OBT courses suspected Comparision abrupt + Spence 1984: to be caused by 30.000 “H + /T + exchange paralleling chronic HTO exposure photosynthesis After 7 weeks abrupt photosynthesis“ 25.000 chronic HTO meets chronic OBT OBT [pCi/gH] forms 20.000 5x larger OBT No photosynthesis Late H + /T + than abrupt because of 15.000 OBT 6 weeks delay 10.000 abrupt HTO start Photosynthesis 5.000 ∼ 10% photosynthetic OBT Early H + /T + 14d 21d 42d 7d 28d 35d 49d 56d 63d 0 0 168 336 504 672 840 1008 1176 1344 1512 Hours HTO Exposure
Chronic HTO exposure Compart ‐ Compart ‐ Compart ‐ Compart ‐ ment No x ment No y ment No x ment No y Timesteps Timesteps OBT content/compartment OBT content/compartment Abrupt start of HTO exposure Compart ‐ Compart ‐ Compart ‐ Compart ‐ ment No x ment No y ment No x ment No y H + migration weeks Timesteps into months Timesteps bio ‐ polymers years OBT content/compartment OBT content/compartment
The XBT buried fraction in mussel OBT Freshwater Mussels Exposed to 4.500 Bq/L HTO Freshwater Mussels Exposed to 4.500 Bq/L HTO Freshwater Mussels Exposed to 4.500 Bq/L HTO 2000 2000 2000 Larvae 1500 1500 1500 Sperm OBT reproduction free OBT [BqL -1 ] Final OBT 100% 1000 1000 1000 20% OBT slow 62% OBT fast by food =XBT (swallowing) 500 500 500 ∆ =1d 18% OBT fast =XBT 0 0 0 (respiration) 0,01 0,01 0,01 0,1 0,1 0,1 1 1 1 10 10 10 100 100 100 Days after Transplantation Days after Transplantation Days after Transplantation
Conclusion OBT formation (abrupt and chronic, fast and slow) can be modeled by respecting ⇒ OBT = XBT buried + CBT ⇒ fast and late window of OBT formation ⇒ XBT buried estimated from XBH ⇒ XBH/compartment from food tables
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