Budijono, BudijonoHasbi, MuhammadPurwanto, EkoHarahap, Sampe2018-03-122018-03-122018-03-12978-602-51349-0-6wahyu sari yenihttps://repository.unri.ac.id/xmlui/handle/123456789/9296Ceratophyllum demersum is a type of drowning macrophytics that plays a key role in freshwater ecosystem and is commonly used in phytoremediation of heavy metals in water. This preliminary study focused on assessing the ability of C. demersum in accumulating heavy metals (Pb and Zn) into their body tissues from heavy metals contained in the water of the Siak River. This plant is grown in natural condition (S. Siak) at different water depth (0,5,5,1 m) with aquatic plant floating raft. Measurement of water samples and water retrieval as well as entire plant tissue per depth for calculated heavy metals at different time intervals (6, 12, 18, 24, 30 days). The results show that the Siak River has been contaminated with Pb and Zn and the concentration of Pb> Zn in C. demersum with each Pb of 0 - 1m water depth is 12.641 mg / kg, 15.659 mg / kg and 16.604 mg / kg of initial concentration of 0.158 mg / kg. The average absorption rate and Pb accumulation per depth are 78.86%, 97.92% and 103.89%, respectively. It was concluded that phosemediation of heavy metal Pb in Siak River was effective with C. demersum up to a water depth of 1 m.enPhytoremediationHeavy MetalCeratophyllum demersumSiak RiverArticle