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USING REGIONAL EXPOSURE CRITERIA AND UPSTREAM REFERENCE DATA TO CHARACTERIZE SPATIAL AND TEMPORAL EXPOSURES TO CHEMICAL CONTAMINANTS
Citation:
Cormier, S., E. Lin, M. R. Millward, M. K. Schubauer-Berigan, D. E. Williams, B. Subramanian, R. Sanders, B. Counts, AND D. Altfater. USING REGIONAL EXPOSURE CRITERIA AND UPSTREAM REFERENCE DATA TO CHARACTERIZE SPATIAL AND TEMPORAL EXPOSURES TO CHEMICAL CONTAMINANTS. Environmental Toxicology and Chemistry 19(4(2):1127-1135, (2000).
Description:
Analyses of biomarkers in fish were used to evaluate exposures among locations and across time. Two types of references were used for comparison, an upstream reference sample remote from known point sources and regional exposure criteria derived from a basline of fish from reference sites throughout Ohio, USA. Liver, bile, and blood were sampled from white suckers (Catostomus commersoni) and common carp (Cyprinus carpio) collected during 1993 and 1996 in the Ottawa River near Lima, Ohio. Levels of exposure were measured for petroleum by naphthalene-type metabolites, combustion by-products by benzo[a]pyrene-type metabolites, coplanar organic compounds by ethoxyresorufin-O-deethylase (EROD) activity, and urea by blood urea nitrogen (BUN) levels. The four biomarkers analyzed proved effective in determining differences between reference and polluted sampling sites, between geographically close(<0.5 km) sites, and between sampling years at sites common in both years. Calculated exposure criteria levels of the polycyclic aromatic hydrocarbon bile metabolites were found to be a conservative approximation of levels from a designated reference site and could thereby permit comparison of biomarker levels of fish from the Ottawa River to a regional reference level. Polycyclic aromatic hydrocarbon bile metabolite and EROD activity levels were more reflective of spatial patterns of contamination than BUN, although all biomarkers indicated differences over time. Biomarkers from white suckers seemed to be more responsive in detecting changes in contaminant levels than the same biomarkers from common carp. Lower levels in 1996 of all biomarkers at many sites suggested lower exposures than in 1993 and could be indicative of some improvement over the period. The usefulness of five extenders for cryopreservation of muskellunge semen was studied in fertilization trials and computer-assisted semen analysis (CASA) of postthaw sperm motility. The effect of prefreezing storage time before cryopreservation on success of cryopreservation was also analyzed. A 50% fertilization rate (compared with fresh semen) of the extender containing 10% dimethyl sulfoxide (DMSO) in seminal-plasma-mimicking medium (SPMM) supplemented by 10% egg yolk was significantly higher than in extenders consisting of 10% DMSO. 0.6 M sucrose, and 10% egg yolk or 20% glycerol and 0.3 M glucose. Spermatozoa cryopreserved with DMSO-SPMM-egg yolk extender had the highest values of straight-line velocity and linearity of movement. Significantly lower fertilizing ability and curvilinear velocity were found for semen specimens stored on ice for 5 h before freezing compared with specimens stored for 1 h. Although spermatozoa cryopreserved with extenders containing 10% methanol had only traces of motility or no motility at all after thawing, fertilization trials indicated that their fertilizing ability was preserved. Despite a lack of motility after thawing, these spermatozoa could have been activated by egg components, thus indicating that they could have been motile during fertilization. This possibility suggests that the motility pattern of muskellunge spermatozoa may be influenced during fertilization by egg components.