Date Approved


Graduate Degree Type


Degree Name

Health Sciences (M.H.S.)

Degree Program

Biomedical Sciences

First Advisor

Daniel Bergman

Second Advisor

Mark Luttenton

Third Advisor

Carl Ruetz III


Nonylphenol is a widely used surfactant subject to ethoxylation and subsists in the environment for significant amounts of time. It has industrial, agricultural, and domestic uses, and makes its way into the aquatic ecosystem despite treatment of wastewater. Detrimental effects of nonylphenol are varied, but most notably endocrine disruption has been examined. Crayfish are a crucial invertebrate in freshwater ecosystems. They are omnivorous, and occupy a key position in the trophic web as both predator and prey. To determine if nonylphenol exposure has any effect on the orientation abilities of crayfish, I acutely (1 day) and chronically (4 days) exposed crayfish to a sublethal amount of nonylphenol. The crayfish then attempted to locate a food odor in a modified Y-maze. Both acutely and chronically exposed crayfish were significantly less successful at choosing the food odor arm than controls, and acutely exposed crayfish also spent significantly less time in the food odor arm. These differences indicate sublethal nonylphenol exposure impairs the orientation ability of crayfish to a food source.