By Garrett Driscoll

Faculty Mentor: Dr. Tyler Frankel

Abstract

Trace metal contamination is a widespread issue due to its many natural and anthropogenic sources and known carcinogenic, teratogenic, and reproductive effects. Sediments enriched with trace metals have been shown to exert negative pressures on individual, population, and ecosystem health. While previous work examining the impacts of trace metals on aquatic invertebrates has primarily focused on freshwater nektonic species, relatively few studies have examined sublethal effects on behavior in sediment-dwelling organisms. As such, this study assessed the effects of cadmium (Cd – 0, 2, 4, 6, 8 and 10 ppm) and lead (Pb – 0, 5, 25, 50, 100 ppm) exposure on the survival and locomotor behavior of the benthic invertebrate Hyalella azteca using spiked sediments. Individual 100 mL acid-washed glass jars were prepared utilizing 35 grams of a given Cd or Pb enriched dried sediment inundated with 50 mL of synthetic freshwater (n = 9). Individual H. azteca were exposed for 9 days at 23°C using static replacement (100% change every 3 days). Individuals were fed a 1:1 diatom to fish flake feed solution (25μL) after each water change. Mortality was monitored every 3 days. After 9d, surviving individuals were placed into a custom behavior chamber and activity was recorded for 3 min. Noldus Ethovision XT 17 was then used to assess differences in distance (cm), velocity (cm/min), acceleration (cm/min2), meander (deg/min), and mobility (%). While this study is still ongoing, we expect to find negative dose-dependent behavioral and locomotor impacts on H. azteca, with Cd causing more harmful effects due to its reportedly higher toxicity. The results of this study will provide a deeper understanding of how trace metal exposure may alter the behavior and survival of benthic organisms within polluted ecosystems.