Bottom sediments of small tidal estuaries located in urban areas

Abstract

Small tidal estuaries located in urbanized areas are subject to multiple influences of processes in the catchment area, natural river and marine factors in the estuary area, as well as anthropogenic use, which leads to changes in natural hydrological, hydrodynamic, hydromorphological processes and pollution of water masses and bottom sediments. The small size of estuaries makes its own adjustments to these processes compared to the mouths of large rivers. The granulometric composition of bottom sediments, the content of organic matter, levels and factors of accumulation of heavy metals (Cu, Zn, Pb, and Cd) in the sediments of the estuaries of small mountain rivers Mackay Creek, Mosquito Creek, Lynn Creek and Seymour, located in the urbanized area of North Vancouver (British Columbia, Canada), were studied. It has been shown that among the many factors influencing the content of heavy metals in estuary sediments, the determining factor is the amount of organic matter present in the sediments. The composition of sediments, the conditions of sorting sediment-forming material and accumulation of heavy metals have a pronounced heterogeneity. The granulometric composition of mineral particles of sediments has a significant effect on the accumulation of heavy metals.