| Summary: | Eels (Anguilla anguilla L.) live in the brackish waters vallis of the Mediterranean, where the elvers enter the lagoons and estuaries and grow in the sheltered areas, feeding on natural food available in the bottom sediments. Eels are therefore exposed to persistent pollutants, such as polychlorinated biphenyls (PCBs) and organochlorine pesticides. These lipophilic xenobiotics tend to accumulate in high concentrations in this species because of its considerable fat amount. Alarming concentrations form heavily polluted areas have been reported in eels; for example, 91% of this species of fish from the lower Elbe River contained levels exceeding the regulatory limits. Moreover, studies from the river Rhine have suggested that the high levels of organochlorine residues found in eels, are due to biomagnification through the food chain. PCBs and chlorinated pesticides have also been detected in different species of fish in the final stretch of the River Po, which is considered a land based source of pollution in the Adriatic Sea. In order to find out whether contamination by PCBs and organochlorine pesticides in the Po Delta poses a risk to human and animal health, studies on the content of the above pollutants in eels were carried out. Twenty eels of 548 +- 126 g weight and 43 +- cm length, were caught twice a year, in March and October 1994. Fish muscles were homogenized in a mixer and freeze-dried. A 30 g sample of the above mixture was dissolved in 20 ml of acetonitrile and placed in an ultrasonic bath for 5 minutes. After sedimentation the supernatant was centrifuged at 1400 rpm for 10 minutes, following which the volume was reduced by means of a rotavapor to about 5 ml and the resulting extract passed through a liquid chromatography LC-18 (octadecyl) column in order to remove lipids and hydrocarbons. Subsequently, this extract was passed through a LC-NH2 (aminopropil) column to remove polar substances such as amines and organic acids and then it was further concentrated under a gentle stream of N2 at room ...
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