This study aims to determine the impact of mining activities on seawater quality and the heavy metal content found in sediments and sea cucumbers in Binebas and Bowone villages, Sangihe Islands, Indonesia. Sampling was conducted in each village, in April, 2026, with three repetitions for water quality measurements, including temperature, pH, turbidity, dissolved oxygen, total dissolved solids, salinity, and sea depth. Sediment and sea cucumber sampling was only conducted once at each location. Analysis of heavy metal content (As, Cd, Hg, and Pb) in sediments and biota (sea cucumbers) was carried out ex situ using the atomic absorption spectrometry (AAS) method. The compliance of the values obtained with environmental quality standards was evaluated. The indications of bioaccumulation and potential ecological risks in the waters around the Sangihe mining sites were examined. The results of this study indicate that all water quality parameters in the waters around the Sangihe mining site are in a tolerable range for marine organisms, including sea cucumbers. Heavy metals, which do not meet quality standards for almost all uses, indicate serious environmental and health risks.
