The Influence of Channel Complexity on Trace Metal Distribution in Salt Impacted Urban Streams

Session: 58. - Cities on the Shore: Urbanization as a Growing Threat to Nearshore Ecosystem Health

Aime Kayembe, University of Toronto, [email protected]
Carl Mitchell, University of Toronto Scarborough, [email protected]

Abstract

Widespread urbanization has led to increased trace metal and salt levels in urban streams because of large local loadings. The geomorphic alterations prevalent in many urban areas, such as channel stabilization practices, alter flow, sediment and solute exchange processes between the stream channel and adjacent hyporheic zone. Hypothetically, these alterations may affect trace metal distribution and transformation in suspended solid phases, creating spatially discrete zones of varying trace metal dynamics. In this study we analyzed trace metal concentrations among predominantly “mobilizable” and “non-mobilizable” fractions in suspended sediments along downstream gradients within different geomorphological units and explored relationships with dissolved organic carbon, major cations and anions, and pH. I all, we sampled and surveyed 12 reaches of varying geomorphic and hydraulic characteristics in three urban watersheds. Additionally, we analysed substrate texture, channel plan-form, bed slope, and degree of rehabilitation and structural controls. We then clustered these channel reaches into three distinct groups of complexity. We will present new data on this study in order to promote a discourse on the role of stream geomorphology on trace metal distribution in salt impacted streams of highly urbanized watersheds.

1. Keyword
urbanization

2. Keyword
water quality

3. Keyword
metals

4. Additional Keyword
Geomorphology