Lead (Pb) Bioaccumulation and Physiological Responses of Acanthus ilicifolius in the Mangrove Forest, Wonorejo, Surabaya, East Java, Indonesia

Mangrove ecosystems in coastal areas are susceptible to heavy metal inputs from various anthropogenic activities. One of the heavy metals frequently found in coastal environments is lead (Pb), which can accumulate in sediments and mangrove vegetation. The Jeruju plant (Acanthus ilicifolius) is a mangrove species capable of absorbing heavy metals from the environment, making it a potential bioindicator of pollution. This study aims to evaluate Pb levels in seawater and sediments, as well as Pb levels in the roots, stems, and leaves of A. ilicifolius; to evaluate its function as a bioaccumulator and translocator; to determine the chlorophyll and protein contents of A. ilicifolius; and to analyze the relationship between Pb levels in A. ilicifolius, chlorophyll content, and protein content of A. ilicifolius. Sampling was conducted at three stations, with three replicates at each station. Lead (Pb) concentration analysis was performed using atomic absorption spectrophotometry (AAS), while protein content analysis was conducted using the Kjeldahl method and chlorophyll content using spectrophotometry. Data were analyzed using descriptive analysis and Pearson’s correlation analysis using SPSS. The results showed that the highest Pb concentrations were found in sediments at 1.135–1.440 mg kg⁻¹. In plant tissues, the highest Pb concentrations were detected in roots, ranging from 0.294–0.380 mg kg⁻¹, and were lower in stems and leaves. Leaf chlorophyll content ranged from 1.133–1.487 mg g⁻¹, while protein content ranged from 13.667 to 16.542%. Correlation analysis results indicated a positive relationship between Pb levels and plant physiological parameters. These findings suggest that A. ilicifolius is still capable of tolerating the presence of Pb without experiencing significant physiological disturbances, making it a potential bioindicator for heavy metal contamination in mangrove ecosystems.