Kaykhosravi, S., Shafii, M., Bhusal, Y., Slowinski, S., Chomicki, K. M., Rezanezhad, F., Van Cappellen, P. (2022) Urban phosphorus load estimation and speciation. May 8-12, IGLAR meeting. https://iaglr.confex.com/iaglr/2023/meetingapp.cgi/Paper/1877

We estimated the annual and seasonal loads of different phosphorus (P) chemical pools exported from two adjacent urban sewersheds (AJE and AJW) discharging in Lake Ontario. The two sewersheds differ in their land use: AJW is more residential and AJE more commercial/industrial. A load-flow regression model and a continuous P model PCSWMM were used and calibrated against measured data. The regression modeling yielded season-dependent export concentrations (ECs) for the two sewersheds. The annual total P (TP) loads from the sewersheds were significantly different (AJE: 0.61±0.05 kg/ha/year; AJW: 0.39±0.07 kg/ha/year). Compared to AJE, the TP loads from the more vegetated AJW were enriched in both total dissolved P (TDP) and dissolved reactive P (DRP). Overall, the TP loads were dominated by particulate P (83-91% of TP), with slightly higher values for AJE. Chemical extractions further suggested that close to half (38-47%) of the particulate P load consists of reactive P species. Thus, DRP alone may not provide a reliable measure of the potentially bioavailable P exported from urban areas.

https://iaglr.confex.com/iaglr/2023/meetingapp.cgi/Paper/1877