Heavy metal contamination suspected of causing mass mortality in seaweed cultivation in waters affected by mining waste

There has been a decrease and a mass death of seaweed, especially in centers where mining exploitation is located. This study was conducted to analyze the content of hazardous heavy at seaweed cultivation locations around the mining area of Morowali Regency. The data collection technique in this study is observation—water measurement and sampling at nine stations. The collected data were then analyzed by the International Modification Association of Official Analytical Chemists (AOAC) method 2005: 999.10, using Flame Atomic Absorption Spectrophotometer (FAAS) and Graphite Furnace Atomic Absorption Spectroscopy (GFAAS). The results showed that the heavy metal content in South Bungku Waters indicates that the heavy metal content is below the threshold the quality standard value based on PPRI no. 22 in 2021. Heavy metal content in Witaponda Waters and Bahodopi Waters indicates that the heavy metal content is above the threshold the quality standard value based on PPRI no. 22 in 2021. In Moahino Village was mercury (0.0036 mg/L) and lead (0.012 mg/L), in Ungkea Village was mercury (0.0018 mg/L) and lead (0.008 mg/L), in Emea Village was mercury (0.0079 mg/L), copper (0.009 mg/L), and lead (0.012 mg/L), in Bahodopi Village 1 was mercury (0.0024 mg/L), chromium (0.01 mg/L), copper (0.011 mg/L), and lead (0.013 mg/L), in Bahodopi Village 2 was mercury (0.0029 mg/L), chromium (0.02 mg/L), cadmium (0.002 mg/L), copper (0.012 mg/L), and lead (0.009 mg/L). It can be concluded that higher levels of heavy metals, which are more dangerous, can harm seaweed's cell structure. Seaweed productivity declines accordingly.