Reconnaissance of 17ß-Estradiol, 11-Ketotestosterone,
Vitellogenin, and Gonad Histopathology in Common
Carp of United States Streams: Potential for
Contaminant-Induced Endocrine Disruption
By Steven L. Goodbred, Robert J. Gilliom, Timothy S. Gross, Nancy P. Denslow,
Wade L. Bryant, and Trenton R. Schoeb
U.S. Geological Survey Open-File Report 96-627
Abstract
A reconnaissance of sex steroid hormones and other biomarkers in common carp
was used to assess whether endocrine disruption may be occurring in fish in
United States streams, to evaluate relations between endocrine disruption and
contaminant levels, and to determine requirements for further studies.
17ß-estradiol, 11-ketotestosterone, vitellogenin, and gonadal histopathology
were measured in adult carp (usually 10--15 for each sex) at 25
sites (647 fish), representing a wide range of environmental settings typical
of major regions of the nation. Fish were collected during August--December
1994, a period of gonadal maturation after spawning. Contaminants evaluated
were organochlorine pesticides and polychlorinated biphenyls in tissue;
phthalates, phenols, and polycyclic aromatic hydrocarbons in bed sediment;
and dissolved pesticides in water. Mean site concentrations
of steroid hormones spanned two orders of magnitude for both sexes. No
significant regional differences in steroid hormones were detected for males,
but females from the Northern and Southern Midcontinent were significantly
different from other regions of the country in one or both hormones. Within
all regions there were significant differences between sites in one or
both hormones for both sexes. Most correlation coefficients between biomarkers
and contaminants were negative. Contaminants that had significant (a=0.05)
correlations with biomarkers were organochlorine pesticides, phenols, and
dissolved pesticides. The strongest pattern common to both males and females
was a negative correlation between the hormone ratio (E
2/11-KT) and dissolved
pesticides. The significant site-to-site differences in biomarkers, and the
presence of significant correlations between biomarkers and contaminants, are
evidence that fish in some streams may be experiencing endocrine disruption.
Improved information is needed to evaluate whether endocrine disruption is
actually occurring and if there are reproductive effects on individual or
populations of carp or other species. Future studies should shift to more
intensive study of fewer sites, including reference and contaminated sites,
in order to address these additional questions.
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