Crawford, Miranda I.2024-04-222024-04-222024-03https://unbscholar.lib.unb.ca/handle/1882/37787Global pesticide use has resulted in widespread environmental degradation, persistent contamination of water sources, and unintended impacts on non-target species. Mixtures of insecticides are commonly found, yet these chemicals are rarely studied in combination. Insecticides frequently found in areas of intensive agricultural land use are particularly concerning as these chemicals likely impact lotic freshwater aquatic benthic macroinvertebrates. This thesis analyzed factors that contribute to the persistence and presence of four commonly detected insecticides and their impact on benthic macroinvertebrates in 10 study watersheds over a greater than 10-year period (2007 to 2021) in Prince Edward Island, Canada, by examining the variability and influence of chemical (insecticides, water quality), biological (benthic macroinvertebrate assemblages), and physical (habitat integrity, water discharge rate) components with regards to agricultural intensity. Agriculturally impacted watersheds had multiple insecticide detections, variable habitats, increased nutrient concentrations, and benthic assemblages, indicative of highly impacted streams.ix, 61electronicenhttp://purl.org/coar/access_right/c_abf2master thesisAlexander-Trusiak, AlexaBiology