Common carp Cyprinus carpio responses to sub-chronic exposure to perfluorooctanoic acid

Perfluorooctanoic acid (PFOA) is an important and diffuse perfluorinated alkylated substance, but knowledge of the toxicological effects of this endocrine disrupter in fish is limited. Adult common carp Cyprinus carpio, L. were exposed to 200 ng/l (a concentration reported in impacted aquatic ecosystems) and 2 mg/l PFOA solutions in a flow-through system for 56 days to determine tissue accumulation and histological alterations of the primary target organs. PFOA was extracted from blood, gill, liver, muscle, kidney, gonad, and brain by an ion-pairing liquid extraction procedure and quantified using high performance liquid chromatography with electrospray ionization tandem mass spectrometry. The limit of detection (LOD) was 0.4 ng/g wet weight (ww). PFOA was not detectable in unexposed fish or in fish exposed to 200 ng/l, but was >LOD in most samples of carp exposed to 2 mg/l. Mean PFOA concentration ranged from 0.5 to 65 ng/g ww, depending on the tissue, with highest levels in the blood and liver. There were no significant differences in condition factor, hepato-somatic index, or gonado-somatic index among the fish of the three groups. Histological, histochemical, and immunohistochemical staining was performed on sections of liver and gonad. Occurrence of atretic oocytes and a paucity of spermatozoa were documented in carp treated with 2 mg/l PFOA. Exposed fish did not show gross hepatic anomalies, but there was enhancement of hepatocytes in proliferation (positive to anti-PCNA antibody) compared to controls.