Isolation and Analysis of Heavy Metal Content in Scales from Three Species of Farmed Fish in Lake Maninjau

¹ Department Aquaculture, Faculty of Fisheries and Marine Science Universitas Bung Hatta Padang, West Sumatera Province, Indonesia
² Department of Fishery Product Processing, Faculty of Science and Technology, Nahdlatul Ulama University of West Sumatera, Padang, Indonesia

^* Corresponding authors: syandri_1960@bunghatta.ac.id

Abstract

The study isolated and analyzed heavy metal content in fish scale from Osphronemus goramy, Cyprinus carpio, and Oreochromis niloticus in Lake Maninjau. Fish weights (n=10) for O. goramy, C. carpio, and O. niloticus were 389.99±24.96 g, 633.30±87 g, and 210.5±12.12 g. Isolation begins with washing scales using running water, followed by 24-hour immersion in 10% NaCl (1:10 w/w) in a refrigerator. Afterward, they are oven-dried at 50°C for 3.5 hours and ground into powder. Fish scale results were analyzed using the dry weight/wet weight formula x 100. AOAC-compliant spectrometry tested heavy metal concentrations of Hg, Pb, Cr, As, Ag, and Cu. Results for O. goramy, C. carpio, and O. niloticus were 65.85%, 61.68%, and 55.63%, respectively. The concentration of heavy metals in O. goramy showed the highest level was Pb (185 mg/kg), followed by Cu (83 mg/kg), Ag (<14.66 mg/kg), Cr (<5 mg/kg), Hg and As (0.43 mg/kg). In C. carpio the highest concentration was Pb (152 mg/kg), followed by Cu (121 mg/kg), Cr (50 mg/kg), Ag (15 mg/kg), Hg and As (<0.50 mg/kg). Meanwhile, in O. niloticus, the highest concentration was Cu (160 mg/kg), followed by Pb (149 mg/kg), Cr (50 mg/kg), Ag (15 mg/kg), Hg and As (< 0.50 mg/kg).