Use of biometric, hematologic, and plasma biochemical variables, and histopathology to assess the chronic effects of the herbicide prometryn on Common Carp.

BACKGROUND

Effects of acute and subchronic exposure of fish to s-triazine herbicides have been well documented, but data on the effects of prometryn on blood analytes in carp at environmentally realistic concentrations are lacking.

OBJECTIVE

The objective of the study was to determine whether biometrics, blood analytes, and histopathology could serve as bioindicators in fish living in waters polluted by triazine.

METHODS

Fish were exposed to prometryn at concentrations of 0.51 (reported concentration in Czech rivers), 8.0, and 80 μg/L for 14, 30, and 60 days. Prior to and during this period, biometrics, blood analytes, and histopathology were evaluated.

RESULTS

After 60 days' exposure to 8.0 and 80 μg/L of prometryn, spleen weights (P < .05) and lactate (P < .01) levels were significantly lower, and concentrations of HGB (P < .01) and MHC (P < .01) and MCHC (P < .01) were higher, relative to controls. After 30 and 60 days' exposure to 0.51, 8.0, and 80 μg/L of prometryn, AST activity, calcium, magnesium, and inorganic phosphate levels were lower (P < .01), while creatinine concentration and ALT activity were higher (P < .01) than in controls. Glucose was higher after exposure to 80 μg/L after 30 and 60 days, and after 60 days' exposure to 8.0 μg/L. Renal histology revealed severe hyaline degeneration of the epithelial cells of caudal kidney tubules in fish at all exposure levels.

CONCLUSIONS

This study shows effects in fish blood at a concentration of 0.51 μg/L of prometryn, a significant finding in view of prometryn reaching a maximum of 4.4 μg/L or less in European rivers. Select blood analytes, such as creatinine, and histologic changes in caudal kidney are potential biomarkers for monitoring residual triazine pesticides in Common Carp.