Environmental Risk Assessment in Sediments Contaminated by Metals from Industrial Activities at the Niteroi Port Complex, Guanabara Bay, Rio De Janeiro

Aquatic ecosystems with metal contamination pose significant risks to both human health and the environment. S & atilde;o Louren & ccedil;o cove in Niter & oacute;i, Rio de Janeiro, adjacent to the Niter & oacute;i Port Complex, is potentially impacted by numerous port terminals and naval industries. Sediment samples from this cove were analyzed for the bioavailability, mobility, environmental risk, and toxicity of metals Cd, Cr, Cu, Ni, Pb, and Zn. The sequential extraction method by the Community Bureau of Reference was employed alongside Inductively Coupled Plasma-Optical Emission Spectrometry. Results revealed severe contamination of all samples with Zn and Cu, with 2/3 exceeding Level 2 of Conama Resolution 454/2012 by over 100%. Cd, Ni, and Zn were identified as the most mobile metals, enriched in the soluble and exchangeable sediment fractions. Despite their high concentrations, Cu and Pb were predominantly found in reducing fractions or adsorbed to organic matter/sulfides in oxidizing fractions. The risk assessment code (RAC) was deemed limited, overestimating Ni's environmental risk while underestimating Cu and Pb in anthropogenically impacted sediments.