Operasional fasilitas nuklir yang ada di Serpong memungkinkan melepas radionuklida ke lingkungan. Isotop Pu merupakan radionuklida yang terlepas ke lingkungan. Lepasan tersebut terbawa oleh air sungai atau run off memasuki Teluk Jakarta. Kerang hijau (Perna viridis) mampu mengakumulasi radionuklida tersebut. Studi ini bertujuan untuk memahami kinetika proses bioakumulasi Pu oleh kerang hijau yang dipengaruhi oleh spesiasinya. Percobaan dilakukan melalui tahapan: aklimatisasi, bioakumulasi (242Pu3+ dan 242Pu4+) dan depurasi. Parameter biokinetika diamati meliputi faktor konsentrasi (CF), konstanta laju pengambilan (ku), konstanta laju pelepasan (ke), faktor biokonsentrasi (BCF), dan waktu paruh biologis (tb1/2). Berdasarkan uji statis non parametric menunjukkan spesiasi 242Pu3+ dan 242Pu4+ berpengaruh terhadap kemampuan Perna viridis mengakumulasi Pu.  Rerata kemampuan bioakumulasi 242Pu4+  oleh Perna viridis adalah 1,2 kali dibandingkan 242Pu4+. Kata kunci : Bioakumulasi , biokinetika,  Perna viridis, plutonium,  spesiasi,  Perna viridis, plutonium. Operations of nuclear facilities in Serpong have potentially release radionuclides to environment. Pu isotope is one of radionuclide that is released into the environment. The release of this radionuclide was carried by the river water or run off entered the Bay of Jakarta. Green mussels (Perna viridis) can be accumulate this radionuclides. The aims of this study was to understand of the biokinetic of Pu bioaccumulation process by green mussels which are affected by its speciation. The experiment was carried out through stages: acclimatization, bioaccumulation (242Pu3+ and 242Pu4+) and depuration. Biokinetic parameters was observed include concentration factor (CF), uptake rate constant (ku), release rate constant (ke), bioconcentration factor (BCF), and biological half-life (tb1/2). Base on non parametric statistic test shown that speciation of 242Pu3+ and 242Pu4+ had an effect on the ability of Perna viridis to accumulate Pu. Avarage of bioaccumulation capabilities of 242Pu4+ by Perna viridis are 1.2 than 242Pu3+. Keywords: bioaccumulation, biokinetics, plutonium, Perna viridis,  speciation.