The impact of an oil spill on organs of bream Abramis brama in the Po River

An oil spill into the River Lambro occurred on 23 February 2010 and reached the Po River the following day. Breams captured here on 1 March 2010, along with a sample from a control site, were examined by light and electron microscopy. The main affected organs were skin and gill with slight or no damage to liver, kidney, and intestine. The gills exhibited lamellar aneurisms, fusion of secondary lamellae, edema with epithelial lifting, mucous cell hypertrophy, and mucus hypersecretion. Significantly higher mucous cell density was observed in the skin of exposed fish. Histochemical staining revealed that acid glycoconjugates were prevalent in epidermal mucous cells in the exposed Abramis brama, whereas neutral and mixed glycoconjugates were dominant in the control fish. Rodlet cells were significantly more abundant in the kidney of exposed fish and showed ultrastructural differences compared to controls. These histopathologic effects were indicators of chemical stress due to exposure to oil. The present study is one of the first which explores the acute effects of this incident and makes part of a few reports focused on freshwater oil spill.

► First study on River Lambro (Italy) oil spill occurred in February 2010.
► Histopathological effects of hydrocarbon mixture on fish.
► Gill and skin are the most affected organs.
► Rodlet cells as biomarkers of chemical stress.
► Usefulness of Abramis brama as sentinel species.