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

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).