The distribution of tritium between water and suspended matter in a laboratory experiment exposing sediment to tritiated water

Following recent suggestions regarding the strong affinity of tritiated water for organic matter in suspended particulates and sediments, two equilibration experiments between sediment organic matter (dry and fresh) and tritiated water were performed to look for potential tritium bio-concentration. The T/H ratios measured at the end of both experiments are lower in the sediment organic matter than in the water, indicating that only a fraction of the hydrogen pool (between 14% and 20%) within the sediment equilibrated with the tritiated water. These results are consistent with the widely used concept of exchangeable and non-exchangeable tritium pools in organic matter and show no sign of tritium bio-accumulation in the sediment relative to water.

► We performed equilibration experiments between sediments and tritiated water.
► The main purpose was to look for potential tritium bio-concentration.
► Initial and final activities of both phases were accurately measured.
► No tritium bio-concentration in the sediment relative to water could be detected.