Synthetic musk in seafood products from south Europe using a quick, easy, cheap, effective, rugged and safe extraction method.

This study aims at developing a method for the determination of 9 synthetic musk compounds in seafood products by combining the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method and determination by gas chromatography mass spectrometry (GC-EI-MS). Method detection limits (MDL) ranging between 0.001 and 1.94 ng g(-1) were obtained. The linearity is higher than 0.9899 in the range MDL - 100 ng g(-1) with precision below 18% and recoveries between 46% and 120% were obtained. The method was applied to quantify musk compounds in seafood products from the European southwest coast (oysters, mussels, salmon organs, glass eels). Galaxolide and Tonalide exhibited the highest concentration levels ranging between MDL - 96.4 ng g(-1) and MDL - 6.85 ng g(-1), respectively. Contamination levels observed for the two nitro musks (musk xylene and musk ketone) are significantly lower ranging between MDL - 0.6 ng g(-1) and MDL - 0.09 ng g(-1), respectively. Analysis of different organs of salmons showed higher concentrations in liver and gonad than in muscle tissues.

Accumulation of Mn, Co, Zn, Rb, Cd, Sn, Ba, Sr, and Pb in the otoliths and tissues of eel (Anguilla anguilla) following long-term exposure in an estuarine environment.

Aiming at increasing the resolution of otolith tracers, we investigated the possibility to use Mn, Co, Zn, Rb, Cd, Sn, Ba, Sr, and Pb otolith composition to retrieve the movements of eels (Anguilla anguilla) in the lower Gironde watershed. Caging experiments were designed to validate the site specific otolith signatures. Individually identified eels were reared in cages in three locations along the estuarine and river gradient. Three trials were set up for successive periods of 3 months and 6 months. Water Mn, Co, Zn, Rb, Cd, Sn, Ba, Sr, and Pb concentrations were monitored. The eel otolith composition corresponding to the experimental period was measured with an ICPMS coupled with a femtosecond laser. Liver Cd, Zn and Pb concentrations were measured. For each caging experiments, we tested the influence of individual weight gain, caging site and trial on elemental otolith concentrations. Mn, Co, Zn, Rb, Cd, Sn, Ba, Sr, and Pb were detected in eel otolith above the detection limits. Otolith Sr and Ba concentrations significantly discriminated the caging sites for one trial. Individual weight gain did not have a significant influence on otolith elemental concentrations. Co, Rb, Cd, Sn, Zn, Sr and Ba otolith concentrations were significantly influenced by the trials. Water elemental composition was only partly reflected by otolith elemental composition. The results showed that otolith composition had a more integrative value than water composition. Complex elemental seasonal variations and individual eel incorporation potential complicated the interpretation of otolith composition. Liver and otolith Cd and Zn concentrations did not show a statistically significant correlation.

The use of Eugenol and electro-narcosis as anaesthetics: transcriptional impacts on the European eel (Anguilla anguilla L.).

Ecotoxicological studies aim to assess the potential environmental risks of various products. This implies the use of various biological models and tests on live animals. In case of handling fish and mammals, ethical rules have to be respected. The use of anaesthesia is considered to be the best way to ensure animal welfare. Eugenol and electro-narcosis are among the most popular chemical and physical anaesthetics used in fisheries and by field biologists. In this study, the genetic and endocrine impacts of these anaesthetics were assessed in order to establish whether the use of such methods could skew the results of ecotoxicological studies. Twenty yellow European eels (Anguilla anguilla) were submitted to Eugenol (50mg/L) and electro-narcosis until they reached a level of deep anaesthesia, while 20 other eels were kept aware. Five anaesthetized and five unanaesthetized eels were sacrificed and analysed directly after treatment and after 1, 7 and 21 days of recovery. At the brain level, Eugenol triggered an increase in the transcription level of genes encoding proteins involved in oxidative stress responses (catalase expression 2.5-fold, mitochondrial superoxide dismutase expression 3-fold), probably due to a hypoxic event during anaesthesia. Later impacts were detected in muscles 21 days after anaesthesia (ATP synthase subunit 6 3-fold, NADH deshydrogenase subunit 5 4-fold and mitochondrial superoxide dismutase 3-fold increased) revealing oxidative stress from an accrued mitochondrial respiratory metabolism. Hormone dosages showed that the use of Eugenol reduced the release of plasma cortisol during anaesthesia. However, this impact seemed to be reversible within one day. In case of electro-narcosis, no significant variation in transcriptional levels could be detected between anaesthetized and unanaesthetized eels. Our results suggest that the use of Eugenol as an aesthetic in ecotoxicological studies measuring gene expression or plasma cortisol concentration is not appropriate, while electro-narcosis does not seem to have any impact, at least on the parameters taken into consideration in this study.