Source and Distribution of Heavy Metals in Sediment Samples from Select Creeks of the Highly Urbanized Metro Vancouver Watersheds, Canada

Abstract

Forty-seven samples collected from 23 creeks in Metro Vancouver, BC, Canada were analyzed to assess how different land use activities affect physicochemical properties in surface water and metal concentrations in sediments. The pH, total dissolved solids (TDS) and electrical conductivity (EC) in surface water samples ranged from 5.50 to 8.27, 14.0 to 410.0 ppm, and 19.0 to 903.0 µS/cm, respectively, with no discernible relationship between the surrounding land use and the parameters. However, land use influenced metal concentrations in the sediments with As, Cd, Cr, Cu, Pb, Ag, and Zn at some locations exceeding the Sediment Quality Guidelines (SQGs). The enrichment factor (EF) value, geo-accumulation index (Igeo), pollution load index (PLI) and concentration factor (CF) indicates most of the sediments are highly contaminated. The geo-accumulation index showed the study area contained extremely contaminated sediment and >64-fold increase due to high levels of Ba, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn. The calculated contamination factors are found to fall in the following sequences: Cd>Ag>As>Pb>Zn>Mn>Cu>Ba>Cr>Ni>V>Fe>Hg in the study area. Creeks closer to highways with heavy vehicular activities reported significantly higher concentrations of metals. Principal component and cluster analyses revealed anthropogenic and natural processes enrich the sediments with metals. It is therefore important to put measures in place to curb increase in metal concentrations in creek sediments.