Grant: Engage Grants Program

Cavendish Farms operates a large potato processing plant in New Annan, PEI. Wastewater from this facility*discharges into the Barbara-Weit estuary. The estuary has undergone eutrophication as a result of municipal*sewage effluent, general nutrient enrichment from agriculture, and the Cavendish effluent. Eutrophication*manifests as an overgrowth of sheets of algae, or sea lettuce, causing displacement of the native seagrass*species). In severe cases, the sea lettuce decomposes in late summer leading to reduced oxygen with potential*mortality of organisms living in the estuary. Cavendish farms is considering removing the effluent discharge,*and land applying the wastewater. Given that land application would be quite costly, and that Cavendish Farm*effluent may or may not itself be contributing significantly to estuarine impacts, a cost benefit analysis is*essential to making such a decision. The first question to be examined is how much of the nutrients entering the*estuary are being contributed by Cavendish Farms? This will be accomplished through measuring the flow,*nutrient concentrations, and determining the origin of nutrients entering the Barbara-Weit estuary. Secondly,*the study will answer the questions of the current health status, or level of eutrophication in this estuary. This*will be partly accomplished by intensive dissolved oxygen monitoring of the estuary. Using regional (Southern*Gulf of St. Lawrence) models already developed by the investigator, this research will use the oxygen data to*answer the question of how much nitrogen reduction is required to improve the oxygen status of the estuary. As*a second measure of eutrophication, the relative distribution of seagrass and sea lettuce will be examined using*boat sonar survey. Regional models that can predict how much nutrient removal is required to restore the*natural plant habitat are also under development. This research will give Cavendish Farms the information to*assess the cost benefits of land application of effluent, provide baseline monitoring for the estuary to document*the benefits of removal of the effluent from the estuary should that occur, and will also contribute data to*regional models to enable cumulative impacts assessment in the Southern Gulf of St. Lawrence.