Effects of wastewater on phosphorus, nitrogen, and nuisance benthic algae in nearshore regions of a large lake.

Upgrading wastewater treatment plants (WWTPs) is a global practice for achieving increasingly stringent nutrient discharge objectives set by governments to accommodate population growth and reduce surface water pollution. However, associated downstream improvements in nutrient conditions are difficult to determine in nearshore regions of large aquatic ecosystems due to complex biophysical processes. We conducted a nine-year water quality study and analyzed the data using linear mixed models (LMMs) within a Before-After-Control-Impact (BACI) framework to assess effects of an upgrade to the Duffin Creek Water Pollution Control Plant (DCWPCP) on surface water nutrient conditions and proliferation of nuisance benthic algae (Cladophora glomerata) in nearshore Lake Ontario.

Effects of detection limits on spatial modeling of water quality in lakes.

Identifying sources and fate of nutrients and pollutants in lake waters is often difficult when key analytes (e.g., dissolved phosphate) are frequently below analytical detection limits (non-detects).

A statistical framework for testing impacts of multiple drivers of surface water quality in nearshore regions of large lakes.

In nearshore regions of large freshwater ecosystems, complex biophysical processes across large geographic regions, combined with the common logistical challenges of data collection by multiple research agencies and shifting monitoring survey designs over time, present challenges for detecting and managing the influence of multiple sources of nutrients and pollution. We present a statistical framework using linear mixed models (LMMs) to test impact of multiple drivers on nearshore water quality of large lakes. Under this framework, we analyzed a 12-year dataset of water quality variables that were measured from a nearshore region along the Canadian shoreline of Lake Ontario (~86 km), near Pickering and Ajax.