Concentrations of Cadmium, Cobalt, Lead, Nickel, and Zinc in Blood and Fillets of Northern Hog Sucker (Hypentelium nigricans) from Streams Contaminated by Lead–Zinc Mining: Implications for Monitoring

Abstract

Lead (Pb) and other metals can accumulate in northern hog sucker (Hypentelium nigricans) and other suckers (Catostomidae), which are harvested in large numbers from Ozark streams by recreational fishers. Suckers are also important in the diets of piscivorous wildlife and fishes. Suckers from streams contaminated by historic Pb-zinc (Zn) mining in southeastern Missouri are presently identified in a consumption advisory because of Pb concentrations. We evaluated blood sampling as a potentially nonlethal alternative to fillet sampling for Pb and other metals in northern hog sucker. Scaled, skin-on, bone-in "fillet" and blood samples were obtained from northern hog suckers (n = 75) collected at nine sites representing a wide range of conditions relative to Pb-Zn mining in southeastern Missouri. All samples were analyzed for cadmium (Cd), cobalt (Co), Pb, nickel (Ni), and Zn. Fillets were also analyzed for calcium as an indicator of the amount of bone, skin, and mucus included in the samples. Pb, Cd, Co, and Ni concentrations were typically higher in blood than in fillets, but Zn concentrations were similar in both sample types. Concentrations of all metals except Zn were typically higher at sites located downstream from active and historic Pb-Zn mines and related facilities than at nonmining sites. Blood concentrations of Pb, Cd, and Co were highly correlated with corresponding fillet concentrations; log-log linear regressions between concentrations in the two sample types explained 94% of the variation for Pb, 73-83% of the variation for Co, and 61% of the variation for Cd. In contrast, relations for Ni and Zn explained <12% of the total variation. Fillet Pb and calcium concentrations were correlated (r = 0.83), but only in the 12 fish from the most contaminated site; concentrations were not significantly correlated across all sites. Conversely, fillet Cd and calcium were correlated across the range of sites (r = 0.78), and the inclusion of calcium in the fillet-to-blood relation explained an additional 12% of the total variation in fillet Cd. Collectively, the results indicate that blood sampling could provide reasonably accurate and precise estimates of fillet Pb, Co, and Cd concentrations that would be suitable for identifying contaminated sites and for monitoring, but some fillet sampling might be necessary at contaminated sites for establishing consumption advisories.

Mercury bioaccumulation and biomagnification in Ozark stream ecosystems

“…Fish age spanned only 2-4 yr in both species at all sites; log 10 -transformed length was therefore the most consistent representation of fish size and age and was used as such in most higher-level statistical analyses. Ca concentrations were significantly greater in hog suckers from EPT than elsewhere (Schmitt et al, 2009). Concentrations were also higher in the smaller hog suckers from JF, CPP, and BGR than in the larger fish from the other sites (Schmitt et al, 2009).…”

“…Ca concentrations were significantly greater in hog suckers from EPT than elsewhere (Schmitt et al, 2009). Concentrations were also higher in the smaller hog suckers from JF, CPP, and BGR than in the larger fish from the other sites (Schmitt et al, 2009). Ca increased with fish size at CWL and CPP, but not at the other sites or when examined across all sites.…”

“…Method limits-of-detection were 0.001-0.010 mg/g dw for HgT and 3.2-11.0 mg/g for Ca, which were exceeded in all samples. Overall, the QA results indicated an acceptable level of precision and accuracy and no evidence of sample contamination (Supplemental Table S -1;Schmitt et al, 2009).…”

“…The samples we analyzed were also used in other studies. Additional information on the field and laboratory methods is available elsewhere Schmitt et al, , 2008Schmitt et al, , 2009). …”

“…Separate aliquots of hog sucker fillets were also analyzed for calcium (Ca) by inductively coupled plasma mass spectrometry as an indicator of the amount of bone, skin, and mucus included in each sample (Schmitt and Finger, 1987;Schmitt et al, 2009). QA measures included blanks, replicates, instrument calibration standards, and certified reference materials analyzed with each group of samples.…”