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 temperature. A gas chromatography-mass spectrometry (Hewlett Packard 5890 GC with a 5989 mass selective detector) equipped with a fused silica capillary column (Alltech SE 30 m x 0.25 mm) was used for the quantification of the pesticides. The operating conditions were as follows: injection port temperature 260 °C, column initial temperature 100 °C, rate of temperature increase 10 °C/min. With a final temperature of 300 °C, helium was used as the carrier gas (25 cm/sec at 200 °C). The mass spectrometer was used in SIM mode (Selected Ion Monitoring) under the following conditions: electron energy 70 eV, source temperature 200 °C, quadrupole temperature 100 °C, electron multiplier voltage 2200 V. The SIM programmes used for the analysis of chlorinated pesticides and PCBs were selected to enable the simultaneous determination of more than fifty compounds. Confirmation and quantification of the various pesticides and PCBs, were carried out by comparison with standard of 99-100% purity (Cambridge Isotope Lab., Woburn, MA, USA). The levels of pollutants found in fish muscle demonstrate the continuing presence of p,p’-DDT (4.16 +- 0.76 µg/kg dry weight) and some metabolites (p,p’-DDE and p,p’-DDD) although it has been banned in Italy since 1978. Contamination with other organochlorinated pesticides was significant, whereas for PCBs high values were found (23.80 +- 8.15 µg/kg dry weight). However, this levels do not present risk for the survival and normal development of fish living in this area. Therefore, there is no real health hazard for people consuming eels caught in waterways form the River Po.

PCBS AND ORGANOCHLORINATED PESTICIDES IN EELS (ANGUILLA ANGUILLA L.) FROM THE PO DELTA.

CIMA, FRANCESCA
1995

Abstract

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 temperature. A gas chromatography-mass spectrometry (Hewlett Packard 5890 GC with a 5989 mass selective detector) equipped with a fused silica capillary column (Alltech SE 30 m x 0.25 mm) was used for the quantification of the pesticides. The operating conditions were as follows: injection port temperature 260 °C, column initial temperature 100 °C, rate of temperature increase 10 °C/min. With a final temperature of 300 °C, helium was used as the carrier gas (25 cm/sec at 200 °C). The mass spectrometer was used in SIM mode (Selected Ion Monitoring) under the following conditions: electron energy 70 eV, source temperature 200 °C, quadrupole temperature 100 °C, electron multiplier voltage 2200 V. The SIM programmes used for the analysis of chlorinated pesticides and PCBs were selected to enable the simultaneous determination of more than fifty compounds. Confirmation and quantification of the various pesticides and PCBs, were carried out by comparison with standard of 99-100% purity (Cambridge Isotope Lab., Woburn, MA, USA). The levels of pollutants found in fish muscle demonstrate the continuing presence of p,p’-DDT (4.16 +- 0.76 µg/kg dry weight) and some metabolites (p,p’-DDE and p,p’-DDD) although it has been banned in Italy since 1978. Contamination with other organochlorinated pesticides was significant, whereas for PCBs high values were found (23.80 +- 8.15 µg/kg dry weight). However, this levels do not present risk for the survival and normal development of fish living in this area. Therefore, there is no real health hazard for people consuming eels caught in waterways form the River Po.
Abstract Book of the International Conference on Chemistry and the Mediterranean Sea (MEDITERRANEANCHEM)
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