Spatiotemporal estimation of heavy metals pollution in the Mediterranean Sea from Volturno River, southern Italy: distribution, risk assessment and loads

With the aim of assess the pollutant load from the Volturno River into the Mediterranean Sea, the amount of some heavy metals (As, Hg, Cd, Cr, Cu, Ni, Pb and Zn) was determined in water dissolved phase (DP), suspended particulate matter (SPM) and sediment samples. Total heavy metal concentrations were in the range 0.20–65.67 μg L⁻¹ (mean value of 12.95 μg L⁻¹) for DP, 1.37–601.77 μg L⁻¹ (mean value of 105.39 μg L⁻¹) for SPM and 14.62–157.33 mg kg⁻¹ (mean value of 55.24 mg kg⁻¹) for sediments. The total heavy metals input are evaluated in about 620.39 kg year⁻¹, suggesting that the river could be an important source of heavy metals in the Tyrrhenian Sea. The ecological risk characterisation was assessed based on the National Water Quality Criteria, by comparison with criterion concentration for chronic and acute toxicity (CCC and CMC), and sediment quality guidelines. Hg and Cd showed higher values than CMC and CCC for most water samples. The Index of Geoaccumulation (<i>I</i>_geo), Contamination Factor, Contamination degree, Pollution Load Index (PLI) and Potential Ecological Risk Index were evaluated. According to <i>I</i>_geo and PLI, the Volturno River was uncontaminated or moderately polluted by heavy metals.