Simultaneous speciation analysis of Hg and Se in fish by high-performance liquid chromatography and inductively coupled plasma-mass spectrometry following microwave-assisted enzymatic hydrolysis

This study reports the development and validation of a new analytical method for simultaneous speciation analysis of Se and Hg in fish muscle. For this purpose, four Se species (selenite/Se(IV), selenate/Se(VI), selenomethionine/SeMet, and selenocysteine/SeCys) and two Hg species (inorganic mercury/iHg and methylmercury/MeHg) were extracted simultaneously by microwave-assisted enzymatic hydrolysis and then separated by HPLC in less than 15 min by using a column with both anion and cation exchange mechanisms and a mobile phase consisting of a mixture of methanol 5% (v/v), 45 mM HNO3, 0.015% 2-mercaptoethanol, and 1.5 mM sodium 3-mercapto-1-propanesulfonate. The separated species of Hg and Se were detected online by inductively coupled plasma-mass spectrometry (ICP-MS). The speciation analysis method was validated by means of the accuracy profile approach by carrying out three series of measurements in duplicate on three different days over a time-span of 3 weeks. The limits of quantification (LOQ) are in the range of 0.010–0.013 mg/kg wet weight (ww) for all selenium species, except for Se(IV) (0.15 mg/kg ww), while the coefficient of variation in terms of intermediate reproducibility (CVR) was < 7%. The LOQ for MeHg was 0.006 mg/kg ww, while the CVR was 3%. The method was successfully applied to the analysis of muscle samples from four different fish species: rainbow trout, tuna, swordfish, and dogfish.This study is a contribution to the Ph.D. research project (MERSEL-FISH) and it was jointly funded by ANSES (France) and INSA (Portugal).info:eu-repo/semantics/publishedVersio

Évaluation du devenir du mercure et du sélénium dans le poisson lors de la cuisson

Les produits de la pêche sont une source importante de nutriments, cependant, ils peuvent accumuler des niveaux substantiels de métaux toxiques, tels que le mercure (Hg). En effet, le poisson représente la principale voie d'exposition des humains au Hg, remettant en cause la consommation régulière d'un tel régime. La majorité des études concernant l'impact toxique du Hg lorsqu'il est ingéré à partir de poisson, a été liée aux niveaux de Hg dans les produits de poisson cru. Cependant, dans la plupart des cas, le poisson est consommé cuit. Plusieurs variables dans les traitements culinaires (température, mode de cuisson, temps, assaisonnement) peuvent influencer la présence de Hg, dans le poisson. De plus, différentes compositions dans la teneur en Se du poisson peuvent également affecter le devenir du Hg pendant les traitements culinaires. Des études antérieures concernant l'influence de différentes procédures de cuisson sur le devenir du Hg, tirent des conclusions contradictoires. Alors que certains d'entre eux observent une concentration réduite de Hg dans le poisson cuit, d'autres signalent son renforcement. Cette étude vise à évaluer l'effet des divers modes de cuisson traditionnels (bouilli, cuisson à la vapeur et grillé) chez différentes espèces de poissons sur la teneur en Hg. De plus, l'influence du Se sur le devenir du Hg pendant la cuisson a également été abordée.FCT, MERSEL-FISH - 2018DAN1568N/

Assessment of the mechanisms and pathways of fish contamination and mercury-selenium antagonism

AIM Mercury (Hg) is one of the most dangerous chemical contaminants for humans and the environment. This is due to its extreme toxicity, particularly in the methylated form, denominated methylmercury (CH3Hg), which is easily absorbed by the body (bioaccumulation). CH3Hg is present in low concentrations in water and in water sediments, and can greatly increase its concentration in aquatic organisms, often reaching more than 85% of total Hg. Therefore, the main source of exposure to CH3Hg is fish consumption, in particular fish from higher trophic levels, since its content tends to increase along the food chain (biomagnification). Nevertheless, it is interesting to note that mercury´s bioavailability seems to be linked to selenium (Se) levels. The Se protective effects against Hg bioaccumulation and toxicity has been identified for the last decades, although the mechanism is still poorly understood. The aim of this study is to accurately assess the Hg-Se interaction in fish and the human dietary exposure. MATERIAL AND METHODS A bioassay was carried out in a representative freshwater fish (rainbow trout) in collaboration with the fish viral pathology unit of ANSES (Ploufragan-Plouzané laboratory). Fish were dietary exposed to CH3Hg under controlled conditions, in the presence or absence of SeMet. The final concentration of CH3Hg and SeMet in the diets was respectively 0,2 μg g-1 and 5 μg g-1. Briefly, six feeding protocols were compared: a non-supplemented diet (control group), a diet supplemented with SeMet, a diet supplemented with MeHg, a diet supplemented with both MeHg and SeMet, a diet supplemented first with MeHg for 1 month and then with SeMet for 2 months and a diet supplemented with SeMet for 1 month and then with MeHg for 2 months. The edible part of fish (muscle) was analysed for SeT and Hgt concentrations by ICP-MS after different time of exposure (1 month, 2 months and 3 months).Este trabalho foi desenvolvido com o apoio da FCT - Project MERSEL-FISH.N/

Assessment of the mercury-selenium antagonism in rainbow trout fish

This study aims at the assessment of mercury (Hg)-selenium (Se) antagonism in fish. For this purpose, rainbow trout fish (Oncorhynchus mykiss) were exposed to methylmercury (MeHg) under controlled conditions, in the presence or absence of selenomethionine (SeMet) using an in-house prepared diet (enriched with MeHg and SeMet at 0.2 μg/g and 5.0 μg/g, respectively). The total duration of the exposure study was 3 months. Fish was sampled and analysed for total Se (SeT) and total mercury (HgT) content after 1, 2 and 3 months of exposure. Six feeding protocols were compared, depending on the exposure type: (i) no MeHg nor SeMet exposure (control group); (ii) exposure to SeMet solely; (iii) exposure to MeHg solely; (iv) exposure to both MeHg and SeMet; (v) exposure first to MeHg during 1 month and then to SeMet during 2 months and (vi), exposure to SeMet during 1 month and then to MeHg for 2 months. The levels of SeT and HgT in the fish (control and supplemented with MeHg/SeMet) were measured by inductively coupled plasma-mass spectrometry (ICPMS). Steadily (linear) bioaccumulation of MeHg in the fish muscle occurred when the fish were exposed individually to this species during the period. The bioaccumulation of MeHg is diminished when the fish are firstly exposed to SeMet and then to MeHg, hence indicating the MeHg detoxification due to SeMet supplementation.Highlights: Assessment of mercury (Hg)-selenium (Se) antagonism in fish through dietary exposure; MeHg saturation intake is reached in fish simultaneously exposed to MeHg and SeMet; This study confirms the detoxification effect of Se and Hg in rainbow trout fish.This project (MERSEL-FISH) was funded by ANSES and INSA.info:eu-repo/semantics/publishedVersio

Determination of total iodine in French Polynesian foods Method validation and occurrence data

International audiencePacific Island populations show some of the highest incidences of thyroid cancer in the world, and iodine deficiency is suspected to play a role. Iodine content was determined in 124 different French Polynesian food samples using inductively coupled plasma-mass spectrometry after alkaline digestion. For samples containing starch, the method was optimised by including an additional enzymatic treatment step. This analytical method was validated with an accuracy profile approach, using certified reference materials with iodine contents ranging from 0.027 to 4.95 mg iodine kg-1 dry weight. The trueness bias ranged from -5.8% to 22.4% and the highest observed intermediate precision coefficient of variation CVR was 11% in starchy materials. Tested Polynesian foods showed large variation in iodine content, with values of 0.014-0.032 mg kg-1 for fruits, 0.014-0.081 mg kg-1 for starchy samples, 0.027-1.85 mg kg-1 for green vegetables, 0.222-5.19 mg kg-1 for fish, 6.51-85.6 mg kg-1 for shellfish, and 0.004-1.39 mg kg-1 for beverages. © 2014 Elsevier Ltd. All rights reserved

Towards a better assessment of the mercury-selenium antagonism in fish

The fish were killed by cutting the spinal cord in t 0 t 1 t 2 and t 3 All the data related to the fish growth were recorded similar growth was observed for all exposure conditions. The levels of Hg T and Se T in the fish diet were also measured by ICP MS. Hg T in control and MeHg spiked diets were 0.05 ±0.002 and 0.24 ±0.01 mg/kg, respectively, whereas Se T were 0.95 ±0.02 mg/kg and 5.41 ±0.36 mg/kg in the control and the spiked diets. Se saturation ( p = 0.30) occurs after two months of fish be exposed throught diet to SeMet solely. Quasilinear (R 2 0.99) bioaccumulation of Hg in the fish exposed individualy to MeHg during 3 months. Threshold (p = 0.30) in total Hg level is reached in fish exposed simultaneously to MeHg and SeMet. ↓ of Hg burden 18%) after two months of fish exposure to SeMet and no MeHg. Possible Hg detoxification due to Se supplementation.FCT, MERSEL-FISH - 2018DAN1568N/

Trace element contamination in fish impacted by bauxite red mud disposal in the Cassidaigne canyon (NW French Mediterranean)

From 1966 to 2015, the Gardanne alumina refinery discharged some 20 million tons of bauxite residue (called red mud) into the Cassidaigne Canyon (northwest French Mediterranean) with impacts on local ecosystem functioning. Although these red muds contained high levels of trace elements (TE), in particular titanium (Ti), vanadium (V), aluminum (Al) and arsenic (As), surprisingly, their impacts on fish contamination levels and the risk related to fish consumption have been little studied until now. Here, 11 trace elements (Al, As, Cd, Cr, Co, Cr, Mn, Ni, Pb, Ti and V) were analyzed in muscle and, when possible, liver, from 1308 fish of 26 species from an impacted zone in the vicinity of the Cassidaigne Canyon and a reference zone, unaffected by red mud disposals. Moreover, 66 arsenic speciation analyses were performed. Although the impact of human activities on the levels of fish contamination by trace elements is generally not easy to assess in situ because it is blurred by interaction with biological effects, we highlighted significant contamination of the fish species collected from the Cassidaigne Canyon, especially by the main trace elements attributable to the discharges of the Gardanne alumina refinery, namely Al, V and Ti. Moreover, inorganic toxic As concentrations were higher in the impacted zone. The results of this baseline research also confirmed the concern previously raised regarding Hg in Mediterranean organisms and that trace element contamination levels in fish are generally negatively related to fish length for all TE except Hg

Accumulation Features of Arsenic Species in Various Fishes Collected from Coastal Cities in Korea

In this study, 36 fish species were collected from three coastal cities in Korea to investigate levels and patterns of six arsenicals (arsenite: As (III), arsenate: As (V), arsenocholine: AsC, arsenobetaine: AsB, monomethylarsonic acid: MMA, and dimethylarsinic acid: DMA). The levels of ???6 As in the different fish species varied substantially, ranging from 0.02 ??g As/g ww (Islaeli carp) to 9.65 ??g As/g ww (Skate ray) with a median of 0.40 ??g As/g ww. All the arsenicals in marine fishes showed higher levels than those in freshwater fishes due to fish feed living in saline water. Overall, marine carnivorous fishes seem to be more contaminated with arsenic. For all the fish samples, AsB (mean fraction: 90.6%) was dominant among the six arsenicals, indicating biomethylation of inorganic arsenic and accumulation of AsB. Fish species with high water contents showed elevated levels of As (III), but there was no further significant correlations between arsenicals and water/lipid contents. Concentrations of As (V) were significantly lower than those of As (III), which implies that As (V) is reduced during biomethylation of inorganic arsenic. Consequently, we hypothesize that the toxicity of arsenic (mainly derived from As (III)) can be increased by the reduction of As (V), especially for the fish species with higher water contents.close