Modeling multi-year phosphorus dynamics in a bioretention cell: Phosphorus partitioning, accumulation, and export

• DOI: 10.1016/j.scitotenv.2023.162749
• Publication Date: 2023-03-10T01:50:09Z
• Authors: Bowen Zhou; Mahyar Shafii; Chris T. Parsons; Elodie Passeport; Fereidoun Rezanezhad; Ariel Lisogorsky; Philippe Van Capp...
• Keywords: Bioretention; Dynamics

Phosphorus (P) export from urban areas via stormwater runoff contributes to eutrophication of downstream aquatic ecosystems. Bioretention cells are a Low Impact Development (LID) technology promoted as green solution attenuate peak flow discharge, well the excess nutrients and other contaminants. Despite their rapidly growing implementation worldwide, predictive understanding efficiency bioretention in reducing P loadings remains limited. Here, we present reaction-transport model simulate fate transport cell facility greater Toronto metropolitan area. The incorporates representation biogeochemical reaction network that controls cycling within cell. We used diagnostic tool determine relative importance processes immobilizing predictions were compared multi-year observational data on 1) outflow loads total (TP) soluble reactive (SRP) during 2012-2017 period, 2) TP depth profiles collected at 4 time points 2012-2019 3) sequential chemical extractions performed core samples filter media layer obtained 2019. Results indicate exfiltration underlying native soil was principally responsible for decreasing surface water discharge (63 % reduction). From 2012 2017, cumulative SRP only accounted 1 2 corresponding inflow loads, respectively, hence demonstrating extremely high reduction this Accumulation predominant mechanism loading (57 retention load) followed by plant uptake (21 retention). Of retained layer, 48 occurred stable, 41 potentially mobilizable, 11 easily mobilizable forms. There no signs capacity approaching saturation after 7 years operation. modeling approach developed here can principle be transferred adapted fit designs hydrological regimes estimate reductions range temporal scales, single precipitation event long-term (i.e., multi-year)