Zebrafish Danio rerio eggs, larvae, and adults can all be used as models for aquatic toxicology. Their small size, short life cycle, and sensitivity to pollutants make them an ideal organism to study the effects of contaminants. This study tests the effects of potential contaminants in stamp sands from a former copper mill in Freda, located in the Keweenaw Peninsula in Michigan’s Upper Peninsula (UP). Stamp sands, a byproduct of copper mining, are a common contaminant along shorelines where they were deposited. They can lead to elevated levels of copper in the water, which has been shown to affect aquatic organisms. This study’s objectives are to determine the effects of stamp sands from Freda on zebrafish at multiple life stages, determine how much copper and other trace elements are leached from the stamp sands into water, and determine if mortality rates of zebrafish differ between fish raised in water contaminated with stamp sands compared to water with sediment from a noncontaminated area and a control. This will provide information on the effects of stamp sands in Freda on sensitive organisms and how much copper from those stamp sands is leached into water.
Larval zebrafish were kept in beakers with 100 mL of water for one week. Five beakers per replicate were used; one beaker with 10 g stamp sand, one with 20 g stamp sand, one with 10 g beach sand (from a rural Eastern UP beach), one with 20 g beach sand, and one with no sediment. Water samples were collected on the first, third, and seventh days. Eggs were subjected to water exposed to the same concentrations of sediments as above for one week. Adult zebrafish were kept in tanks with a layer of stamp sand, beach sand, or no sediment for one week, then examined using uXRF spectrometer for elemental imaging and ICP-MS analysis for tissue element quantification. Water samples were taken at the conclusion of the experiment. All water samples were analyzed on an ICP-MS for copper and other metals. Mortality and hatch rates were compared with ANOVA and Tukey tests on R Studio.
Results will show if any differences in hatch rates or mortality rates occur between the stamp sands, beach sands, or controls. The uXRF imaging results will show where contaminants concentrate in zebrafish. The ICP-MS will show how much copper and other trace elements are present in the water and bioaccumulate in the fish. Further research on the effects of stamp sands from Freda on aquatic and terrestrial organisms is needed for a more complete understanding of how they impact the environment.