Pacific salmon populations have declined markedly in the Western United States. Of particular concern has been sublethal neurological injury occurring in salmon exposed to certain pesticides and trace metals. These behavioral impacts include loss of predator detection and prey selection, altered reproductive timing and loss of homing. These aforementioned neurobehavioral effects observed in individuals are now linked to population impacts. The salmon olfactory system is a sensitive target for the neurotoxicity of environmental chemicals, including metals and pesticides commonly found in Superfund sites. However, little is known about the mechanisms of chemical olfactory neurotoxicity in fish. Studies from our first funding cycle have produced important findings that will be explored in detail in our competitive renewal. Specifically, we know that: 1) the olfactory tissues of salmon are important site of chemical biotransformation, and in particular, cytochrome P4503A and flavin monooxygenases (FMO) appear to mediate tissue- and compound-specific differences in organophosphate biotransformation with potential impacts on neurotoxicity, 2) the olfactory injury by a model superfund organophosphate chemical (chlorpyrifos) and metal (copper) involves disruption of olfactory signal transduction pathways. However, copper primarily impacts G-protein coupled olfactory receptor signaling, likely through oxidative stress, whereas chlorpyrifos activates genes involved in the inhibition of olfactory signal transduction, and 3) transcriptional signatures can help us identify unique gene targets relevant to mixtures, as well differentiating metal- and organophosphate-driven affects. Based upon our findings, the objectives of the competing renewal are to: 1) use cDNA cloning, recombinant protein expression, microarray analysis and enzymatic approaches to determine the role of olfactory CYP3A and flavin monooxygenases in organophosphate neurotoxicity in salmon during movement from freshwater to saltwater, 2) use in situ hybridization and immunohistochemistry analyses coupled with behavioral studies to understand the role of oxidative stress in copper and cadmium-mediated olfactory injury, 3) use proteomics approaches to identify and discriminate important olfactory protein targets of copper and chlorpyrifos, 4) use a suite of olfactory biomarkers generated from the aforementioned studies to assess sublethal olfactory neurotoxicity in salmon migrating through Superfund sites.

Public Health Relevance

The results this project will greatly increase our understanding of the mechanisms and consequences of sublethal neurotoxicity in salmon populations, and will use mechanistically-based biomarkers to identify salmon undergoing behavioral injuries as a consequence of chemical exposures at Superfund sites. Furthermore, this study has global implications for the consequences of aquatic pollution to freshwater and marine fish, which rely heavily upon proper olfactory functioning for the maintenance of normal behaviors critical to survival and reproduction.

National Institute of Health (NIH)
National Institute of Environmental Health Sciences (NIEHS)
Hazardous Substances Basic Research Grants Program (NIEHS) (P42)
Project #
Application #
Study Section
Special Emphasis Panel (ZES1-LKB-D)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Washington
United States
Zip Code
Ma, Eva Y; Heffern, Kevin; Cheresh, Julia et al. (2018) Differential copper-induced death and regeneration of olfactory sensory neuron populations and neurobehavioral function in larval zebrafish. Neurotoxicology 69:141-151
Heffern, Kevin; Tierney, Keith; Gallagher, Evan P (2018) Comparative effects of cadmium, zinc, arsenic and chromium on olfactory-mediated neurobehavior and gene expression in larval zebrafish (Danio rerio). Aquat Toxicol 201:83-90
Racette, Brad A; Gross, Anat; Criswell, Susan R et al. (2018) A screening tool to detect clinical manganese neurotoxicity. Neurotoxicology 64:12-18
Barrett, P M; Hull, E A; King, C E et al. (2018) Increased exposure of plankton to arsenic in contaminated weakly-stratified lakes. Sci Total Environ 625:1606-1614
Rooney, James P K; Woods, Nancy F; Martin, Michael D et al. (2018) Genetic polymorphisms of GRIN2A and GRIN2B modify the neurobehavioral effects of low-level lead exposure in children. Environ Res 165:1-10
Chang, Yu-Chi; Cole, Toby B; Costa, Lucio G (2018) Prenatal and early-life diesel exhaust exposure causes autism-like behavioral changes in mice. Part Fibre Toxicol 15:18
Criswell, Susan R; Nielsen, Susan Searles; Warden, Mark et al. (2018) [18F]FDOPA positron emission tomography in manganese-exposed workers. Neurotoxicology 64:43-49
Wang, Hao; Zhang, Liang; Abel, Glen M et al. (2018) Cadmium Exposure Impairs Cognition and Olfactory Memory in Male C57BL/6 Mice. Toxicol Sci 161:87-102
Criswell, Susan R; Warden, Mark N; Searles Nielsen, Susan et al. (2018) Selective D2 receptor PET in manganese-exposed workers. Neurology 91:e1022-e1030
Meador, James P; Yeh, Andrew; Gallagher, Evan P (2018) Adverse metabolic effects in fish exposed to contaminants of emerging concern in the field and laboratory. Environ Pollut 236:850-861

Showing the most recent 10 out of 455 publications