Assessment of heavy metal contamination and ecological risk in the Klang Mangrove sediments: implications for sustainable development in Pulau Indah, Malaysia.

This study investigates the physicochemical properties and heavy metal concentrations (As, Cu, Cd, Cr, Ni, Zn, Pb) in the sediments of the Klang Mangrove Area, with a focus on assessing pollution risks associated with Pulau Indah's industrial activities in Malaysia. The sediments were characterized by moisture content ranging from 31 to 37%, pH levels ranging from acidic to neutral, slightly saline conditions, sandy textures, and organic matter averaging 9.74% (7.04% organic carbon). Heavy metals were analyzed using ethylenediaminetetraacetic acid (EDTA) and Aqua Regia extraction methods to distinguish between bioavailable and total metal concentrations. The study found elevated Cd concentrations across all sites, exceeding both the threshold effect level (TEL) and probable effect level (PEL), reflecting EDTA's efficiency in mobilizing bioavailable Cd. Pb, Ni, and Cu also exceeded TEL but remained below PEL. Notably, Aqua Regia extraction identified Cu concentrations at Site 3 (175.9 mg kg) exceeding TEL (31.6 mg kg) and PEL (149 mg kg), likely due to Aqua Regia's capacity to dissolve stable and bioavailable metal forms. Other metals, such as As, Zn, and Cr, remained below harmful thresholds. Based on Hakanson's classification, the contamination degree (CD) value at site three was 23.75, categorizing it as highly contaminated. The results underscore significant ecological risks at site three, particularly from Cu, along with moderate contamination driven by Cd and Pb. This study highlights the urgent need for remediation strategies and sustainable environmental management to mitigate contamination risks, safeguard aquatic ecosystems, and protect public health in Pulau Indah. The findings contribute novel insights into the region's sediment contamination, providing essential data for policymakers and stakeholders to implement effective pollution control measures.