Wildfires are natural disturbances in the western United States, but fire suppression and climate change have increased their frequency, size, and severity. High-elevation watersheds, which provide critical habitats for aquatic organisms, are particularly vulnerable to fire disturbance. Intense fires remove vegetation and increase soil hydrophobicity, leading to greater sediment input during storm events. Compounding these effects, numerous mine sites in the region discharge toxic metals into waterways during runoff. The impacts of wildfire and mining degrade water quality and harm aquatic life, highlighting the need to study their combined and potential interactive effects. We used a stream mesocosm experiment to examine how sediment and metals affect aquatic macroinvertebrates. Macroinvertebrate communities were collected from the upper Arkansas River near Leadville, Colorado—a historically mined but unburned watershed. Sixteen mesocosms were randomly assigned to one of four treatments: control, metals only, sediment only, and combined sediment + metals. Sediment-treated mesocosms received 2,200 g of sediment in a single pulse. Metal-treated mesocosms received 25 µg/L Copper and 500 µg/L Zinc per pulse, introduced at 10 ml/min over 24 hours. Dissolved metal concentrations and periphyton biomass were recorded throughout the experiment. Preliminary results indicate all treatments increased macroinvertebrate mortality and reduced periphyton biomass, with sediment having a more pronounced impact than metals alone. Sediment smothering likely caused greater mortality, especially as these communities are relatively tolerant to metals. Reduced periphyton, a food resource for grazing macroinvertebrates, likely exacerbated mortality by limiting food availability. Interestingly, dissolved metal concentrations were lower in sediment + metal treatments compared to metal-only treatments, suggesting that metals were absorbed by sediment and other organic particles. Although reduced bioavailability may lessen toxicity, sediment effects appeared to dominate, driving changes in the biotic community. These findings highlight the potential for sediment and metals to interactively affect stream macroinvertebrates, which may be of increasing significance in nature given the widespread co-occurrence of both stressors.