Toxicity Assessment of Heavy Metals in Leachate From Dredged Sediments Deposited Near Residential Areas: Implications for Environmental and Human Health Risk

Abstract

ABSTRACT This study evaluates the heavy metal concentrations in the sediments from the Korle Lagoon dumpsite and their potential leaching into the environment. The sediments were analyzed for total heavy metal concentrations using USEPA Method 3050B, with results showing the following ranges: 19.715–44.471 mg/kg for Cu, 0.098–0.398 mg/kg for Cd, 2.891–4.385 mg/kg for As, 26.00–45.176 mg/kg for Cr, 6.656–9.072 mg/kg for Ni, 33.932–60.029 mg/kg for Pb, 0.092–0.172 mg/kg for Hg, 111.9–214.88 mg/kg for Zn, and 12,884–19,192 mg/kg for Fe. Leachates from the sediments were analyzed using the Toxicity Characteristic Leaching Procedure (TCLP) according to USEPA Method 1311. The metal concentrations in the leachate ranged from 0.002 to 0.005 mg/L for As, ND to 0.01 mg/L for Cd, 0.012 to 0.044 mg/L for Cu, 0.012 to 0.031 mg/L for Cr, 0.039 to 0.114 mg/L for Ni, 0.971 to 1.639 mg/L for Fe, ND to 0.001 mg/L for Hg, and 0.104 to 3.250 mg/L for Zn, with all leachate concentrations below the recommended guideline limits. The cumulative progressive TCLP results also showed metal concentrations below the guideline levels, suggesting that the leachate does not pose an immediate environmental risk. However, the study notes that while the current levels are within safe limits, significant leaching could occur if the pH of the medium decreases, potentially leading to environmental impacts over time. This research provides valuable insights into the current stability of the Korle Lagoon dumpsite sediments and establishes a baseline for future studies on long‐term environmental risks. The findings underscore the need for continued monitoring of pH changes and metal leaching to predict future environmental impacts.