Temporal variation and risk assessment of heavy metals and nutrients from water and sediment in a stormwater pond, Brazil

Urban watercourses are under pressure owing to the inflow of environmental pollutants from stormwater and effluent. The concentrations ofheavy metals, ammoniacal nitrogen, total phosphorus (TP), and physicochemical parameters were monitored in a sediment pond in theBrazilian Midwest. The correlation between the variables and the degree of sediment contamination was verified using the GeoaccumulationIndex (Igeo), Contamination Factor (CF), and Pollutant Load Index (PLI). The general concentrations of the metals were in the order Mn > .B > .Ba. > Zn.> Cu. > Cr > Pb > Ni in the water and Mn > Cr.Ba > B. > Zn > .Cu. > Ni > .Pb in the sediment. The concentrations of Ba, Cr, Cu, Mn,Ni, Pb, and TP in the water exceeded the regulatory limits at least one. The mean concentrations of Cr, Cu, and Ni in the sediment sampleswere 6.32, 1.63, and 2.61 uppers than the background values. The applied geochemical indices indicated a moderate to a very high degree ofsediment contamination, suggesting the anthropogenic origin of Cr, Cu, and Ni. Significant Pearson correlations were observed between tur-bidity and total suspended solids (TSS), Ba, Cr, Mn, Zn, and TP. Ponds and urban lakes require maintenance or may become a source ofenvironmental pollutants