U.S. Geological Survey
Toxic Substances Hydrology Program--Proceedings of the Technical Meeting
Charleston South Carolina March 8-12, 1999--Volume 2 of 3--Contamination of Hydrologic Systems and Related Ecosystems, Water-Resources Investigations Report 99-4018B
Biomonitoring of Environmental Status and Trends (BEST) Program: Contaminants
and Related Effects in Fish from the Mississippi, Columbia, and Rio Grande Basins
By C.J. Schmitt, T.M Bartish, V.S. Blazer, T.S. Gross, D.E. Tillitt, W.L. Bryant,
and L.R. DeWeese
This report is available in
pdf format: Schmitt.pdf
ABSTRACT
The Biomonitoring of Environmental Status and Trends (BEST) Program was initiated,
in part, as a revision and expansion of the National Contaminant Biomonitoring
Program (NCBP). One aspect of the BEST program focuses on monitoring contaminants
and effects across broad geographic areas. This approach is currently being
tested in the Mississippi, Columbia, and Rio Grande basins. The overall objectives
of this project are to describe the occurrence and distribution of contaminants
and their effects on fish in the three basins; to quantitatively evaluate the
performance of aquatic methods used by the BEST program; and to evaluate potential
collaborations with the National Stream Quality Accounting Network (NASQAN-II)
and the National Water Quality Assessment (NAWQA) programs of the USGS-Water
Resources Division. Fish were collected from 46 sites in the Mississippi River
basin (1995); 16 sites in the Columbia River basin (1997); 10 sites in the Rio
Grande basin (1997); and from a reference site in West Virginia. Sites were
located at the historic NCBP fish monitoring stations in all three basins; at
NASQAN-II water quality sampling sites in the Columbia and Rio Grande basins;
and at NAWQA sites in the Mississippi Embayment and Eastern Iowa Basins study
units within the Mississippi River basin. The primary species targeted at each
site were common carp (Cyprinus carpio) and largemouth bass (Micropterus
salmoides); other species, mostly other black basses (Micropterus spp.),
percids (Stizostedion spp.), salmonids, suckers (Catostomidae),
and catfish (Ictaluridae) were collected as alternates, depending on
habitat and location. Individual fish (about 40 per station) were analyzed for
reproductive biomarkers (vitellogenin and sex steroid hormones), histopathological
alterations, macrophage aggregates, EROD activity, lysozyme activity, and general
fish health measures (organosomatic and ponderal indices, observations of grossly
visible lesions, deformities, and parasites). Organochlorine (pesticides and
total PCB's) and elemental (heavy metals and metalloids) contaminant analyses
and the H4IIE bioassay for dioxin-like activity were performed on fish samples
composited by species and sex. In the Mississippi basin, DDT (mostly as p,p'-DDE)
residues in fish remained sufficiently high in the southern parts of the watershed
to represent a hazard to sensitive species of fish-eating birds. Toxaphene residues
also remained evident. The combined results of organochlorine chemical, H4IIE
bioassay, and biomarker analyses also indicated the presence of other organic
contaminants in the lower Mississippi valley. Cyclodiene pesticides (dieldrin,
endrin, and chlordane) were present in many agricultural areas, especially in
the Corn Belt. Concentrations of these pesticides were also elevated at Memphis,
Tennessee, where there is a point-source. Selenium concentrations were sufficiently
high to constitute a hazard to piscivorous fishes and wildlife in the upper
Arkansas River, where levels have been increasing for approximately 10 years.
As expected, mercury concentrations were higher in the predator species than
in bottom fish. The occurrence of vitellogenin in plasma and of ovarian cells
in the testes of male fish from several sites, along with abnormal ratios of
sex steroids, suggest that fish from some sites are exposed to endocrine-modulating
substances.
|
|