Skeletal abnormalities in juvenile fish from the cooling pond of the Chornobyl nuclear power plant

Skeletal abnormalities in juveniles of common roach (Rutilus rutilus) and common rudd (Scardinius erythrophthalmus) from the cooling pond of the Chornobyl NPP were studied. We observed abnormalities and structural disorders of the caudal and abdominal segments. Abnormalities such as additional processes of neural and haemal spines, partial or total vertebral fusions, deformation of the last vertebra of the caudal section, deformation of spine and deformation of the ribs were found. Abnormalities in the common roach also included significant curvatures of the ribs. Quantitatively, both populations showed significant numbers of rib deformations (Pidbirna Lake, control water body—93%; Chornobyl NPP cooling pond—95% of the total individuals), but qualitatively, the deformations of the ribs in fish from the Chornobyl NPP cooling pond were much more pronounced. We found 13 types of abnormalities localized in two main parts of the skeleton. It was determined that the number of observed abnormalities depended on the level of radioactive contamination of water bodies and absorbed dose rate for fish. The individual spectrum of abnormalities for the control populations did not exceed five abnormalities per individual, while in the Chornobyl NPP cooling pond populations, up to 29 abnormalities per individual were observed with some individuals showing multiple vertebral abnormalities. Overall, these findings suggest very strong effects of radioactive contaminants on fish growth and development