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Concentration factors (CFs) for 27 radionuclides in marine and freshwater fish were reviewed, as were factors that may influence the dose commitment to man resulting from the consumption of fish. These factors include environmental partitioning, ecological trophic level discrimination and specific tissue accumulation (tropism). Our recommendations are based first on field data for radioisotopes of each element; second, on data for stable elements for which data on radioisotopes are lacking; and third, on the potential for bioaccumulation, which is influenced most by the established biological significance of the element or its chemical similarity to biologically active elements in the same chemical group. Only radionuclides of elements with known biological functions or their analogues accumulate to significant levels in fish tissue. The environmental data that exist for Cs, Sr, Co, Fe, Mn, I, P, Am, Cm, Np and Pu were used for adjusting CFs based on water quality or trophic status of fish. Separate CFs have been listed for particular groups of fish that showed a high propensity for certain radionuclides to accumulate in tissue at higher specific activity than that found in water.

Eventual development of fusion power reactors could increase the mining, use and disposal of lithium five-fold by the year 2000. This study has investigated potential effects from unusual amounts of lithium in aquatic environments. Freshwater organisms representing a Pacific Northwest salmonid habitat were exposed to elevated concentrations of lithium. Nine parameters were used to determine the incipient toxicity of lithium to rainbow trout (Salmo gairdneri), insect larvae (Chironomus sp.) and Columbia River periphyton. All three groups of biota were incipiently sensitive to lithium at concentrations ranging between 0.1 and 1 mg/L. These results correspond with the incipient toxicity of beryllium, a chemically similar component of fusion reactor cores. A maximum lithium concentration of 0.01 mg/L occurs naturally in most freshwater environments (beryllium is rarer). Therefore, a concentration range of 0.01 to 0.1 mg/L may be regarded as "approaching toxic concentrations" when assessing the hazards of lithium in freshwaters.

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