Study of Bioaccumulation of Heavy Metals Mercury (Hg) and Tin (Sn) in Traditional Seaweed (Caulerpa racemosa) Cultivation in Brondong, Lamongan

Abstract Organisms such as Caulerpa racemosa seaweed, which play a pivotal role as primary producers in marine ecosystems, are particularly vulnerable to the deleterious effects of heavy metal exposure. Thus, comprehending the levels of heavy metals, in conjunction with parameters such as the bioconcentration factor (BCF) and geoaccumulation index (Igeo), pertaining to mercury (Hg) and lead (Pb) within the sediment and C. racemosa seaweed in Brondong, Lamongan is imperative for safeguarding the safety of seaweed-derived food products. Sampling of C. racemosa was conducted within traditional seawater ponds utilized for the cultivation of giant groupers, alongside other varieties of seaweed. The concentrations of heavy metals in various anatomical components of the seaweed (ramuli, stolons, rhizoids) and sediment were determined through spectrophotometric analysis utilizing Inductively Coupled Plasma Mass Spectrophotometer (ICP-MS). Laboratory analyses disclosed mercury (Hg) concentrations in C. racemosa ranging from 0.0212 ppm in rhizoids to 0.00437 ppm in ramuli, whereas tin (Sn) concentrations exhibited variability from 0.0392 ppm in rhizoids to 0.0390 ppm in ramuli. While mercury remained undetectable in sediment samples, moderate concentrations of tin were observed at approximately 2.10 ppm. The calculated bioconcentration factors (BCF) for tin in different segments of C. racemosa ranged from 0.0187 ppm to 0.0114 ppm, suggesting a low degree of bioaccumulation. Geoaccumulation index (Igeo) values spanned from -4.1876 to -4.2186 across distinct segments of C. racemosa , indicating marginal accumulation of heavy metals.