Potential for Heavy Metal Contamination in the Brown Macroalgae Padina australis from the Kayoa Islands, South Halmahera

Abstract

Brown algae (Padina australis) are one of the macroalgae that have the ability to accumulate heavy metals, making them a bioindicator of environmental pollution levels. The waters of the Kayoa Islands, South Halmahera, are part of an area known as the world’s coral triangle. This study aims to determine the levels of heavy metals Cd, Pb, and Hg accumulated in the brown algae Padina australis. The research method used was a wet destruction process and the samples were analyzed using an Atomic Absorption Spectrophotometer (AAS). The results obtained in this study from three sampling locations, namely the South, North, and West directions of the Kayoa Archipelago, show that Cd concentrations were higher compared to Pb and Hg concentrations. The Cd concentration was 0.69 mg/kg in the South, 0.62 mg/kg in the North, and 0.37 mg/kg in the West. The Pb concentration was 0.62 mg/kg in the South, 0.55 mg/kg in the North, and 0.34 mg/kg in the West. Meanwhile, the Hg concentration was 0.11 mg/kg in the South, 0.095 mg/kg in the North, and 0.075 mg/kg in the West. The levels of heavy metals Cd, Pb, and Hg detected in the brown algae Padina australis were still below the threshold quality standards of SNI 7387:2009 and FAO/WHO (2004). However, these levels should remain a concern for the local government because the accumulation of heavy metals can persist in aquatic biota over time. The results of this study can serve as a guideline for the management and mitigation of heavy metal pollution in the coastal and marine environments of South Halmahera.