Modeling Cyanotoxin Production, Fate, and Transport in Surface Water Bodies Using CE-QUAL-W2

Cyanobacteria are frequently associated with forming toxic blooms. The toxins produced by cyanobacteria, cyanotoxins, are harmful to both humans and animals. Rising temperatures due to global climate change are expected to increase the occurrence of cyanobacteria, and it is vital that we protect our drinking water supplies and natural water resources. Modeling the production, fate, and transport of these toxins is an important step in limiting exposure to them and evaluating management strategies to mitigate their impact. The research provided here offers an overview of some of the main cyanotoxins of concern and presents preliminary models for the transport and fate of these toxins. Cyanotoxins can be either intracellular or extracellular, and a model for each was developed. The models were incorporated into the two-dimensional (longitudinal and vertical) hydrodynamic and water quality model CE-QUAL-W2. The toxin models were tested using a model of Henry Hagg Lake (Oregon, USA). The models were able to produce similar trends as found in published data, but since the toxin data available at Henry Hagg Lake was minimal, no direct comparisons between model results and field data were made. Four scenarios were conducted to test the functionality of the toxin models in CE-QUAL-W2. The predicted results from each test scenario matched the expected outcomes based on the parameters used in each scenario. Further applications of the toxin models to other water bodies with more consistent toxin data will help verify the accuracy of the models. This research provides a first step at modeling cyanotoxins using CE-QUAL-W2 and provides a framework to further develop the models through continued research of the cyanotoxins.