[en] Melamine (2,4,6 triamino-s-triazine) is a starting material for the manufacture of polymeric resins, thermosetting plastics, and housewares. The uptake, bioaccumulation and elimination of uniform triazine-labelled [¹⁴C]-melamine was determined in fingerling rainbow trout. Uptake into tissues was monitored in a static exposure system (water conc. = 89-91 ppb) until the steady state of melamine was reached in the fish tissues. The bioconcentration factor (BCF) was determined for muscle and viscera at the steady state. Uptake of [¹⁴C] melamine was low for both muscle and viscera, achieving levels only as high as 10 ppb in either compartment. Steady state was reached in the viscera within 48 hours and in muscle after only 16 hours. The BCF for muscle (0.03 to 0.11) and viscera (0.5-0.11) was less than unity, indicating a propensity of this compound to resist partitioning into the fish or fish tissues. This may be related to high hydrophilicity or a strong solute-solute interaction of malamine. In depuration studies, the half-life of malamine was found to be relatively short +1/2 viscera = 8.06 found to be relatively short (+1/2 muscle = 8.79 hrs), consistent with the rapid achievement of steady state and low BCF