|SREL Reprint #0533|
Frequency Distribution of Trace Metal Concentrations in Five Freshwater Fishes
P. Giesy, Jr. and James G. Wiener
Whole body concentrations of Cd, Cr, Cu, Fe, and Zn
were determined for samples of chain pickerel (Esox niger),
bluegill (Lepomis macrochirus), blueback herring (Alosa aestivalis),
brook silverside (Labidesthes sicculus), and golden shiner (Notemigonus
crysoleucas) from a 1,120-hectare impoundment near Aiken, South Carolina.
Species differences in mean concentrations were found for all five
elements. Frequency distributions of 23 species-element groupings were
compared to the normal, lognormal, Weibull, and exponential distributions.
The lognormal, normal, Weibull, and exponential distributions had the
best fit to 57, 17, 26, and 0 percent of the species-element groupings,
respectively. Four of the 23
species-element groupings departed significantly from all four of the
distributions, primarily as a result of strong positive skewness.
All species for which Cd and Cr were studied exhibited significant
positive skewness, whole skewness was less pronounced for concentrations of Cu,
Fe, and Zn. Most samples to which
the Weibull distribution gave the best fit did not depart significantly from
either the lognormal or normal distribution.
Therefore, in most cases either the normal or lognormal distribution may
be satisfactorily employed as statistical models of frequency distributions of
trace metal concentrations in fishes. Known
required elements (Cu, Fe, and Zn) tended more towards normality than Cd and Cr,
which followed lognormal distributions.
SREL Reprint #0533
Giesey, J.P., Jr. and J.G. Wiener. 1977. Frequency
distributions of trace metal concentrations in five freshwater
fishes. Transactions of the American Fisheries Society 106:393-403.