A novel analytical approach for the determination of ethylene-thiourea and propylene-thiourea in vegetal foodstuffs by high-performance liquid chromatography hyphenated to inductively coupled plasma-tandem mass spectrometry.

This study reports a novel analytical approach for the simultaneous determination of ethylene-thiourea (ETU) and propylene-thiourea (PTU) in fruits and vegetables by (reverse phase) high-performance liquid chromatography (HPLC) coupled to inductively coupled plasma-tandem mass spectrometry (ICP-QQQMS or ICP-MS/MS). A baseline separation of ETU and PTU was achieved in less than 5 min. A robust method validation by using the accuracy profile approach was performed by carrying out four measurement series in duplicate at six different levels over a timespan of 4 weeks (different days). The recovery factors ranged from 87 to 101% for ETU and from 98 to 99% for PTU (depending on the spiking level). The coefficient of variation in terms of repeatability (CVr) ranged from 1 to 4.7% for ETU and from 1.8 to 3.9% for PTU (depending also on the analyte level) while the coefficient of variation in terms of intermediate reproducibility (CVR) ranged from 3.4 to 10% for ETU and from 1.8 to 10.8% for PTU. The limit of quantification was 0.022 mg kg-1 (wet weight) for ETU and 0.010 mg kg-1 (ww) for PTU. This novel approach was proved to be highly robust and suitable for the determination of ETU and PTU in foodstuffs of vegetal origin.

Approaches to determine pesticides in marine bivalves.

Due to agricultural runoff, pesticides end up in aquatic ecosystems and some accumulate in marine bivalves. As filter feeders, bivalves can accumulate high concentrations of chemicals in their tissue representing a potential risk to the health of human and aquatic ecosystems. So far, most of the studies dealing with pesticide contamination in marine bivalves, for example, in the French Atlantic and English Channel coasts, have focused on the old generation of pesticides. Only a few investigated the newly emerging pesticides partly due to methodological challenges. A better understanding of the most sensitive and reliable methods is thus essential for accurately determining a wide variety of environmentally relevant pesticides in marine bivalves. The review highlighted the use of more environmentally friendly and efficient materials such as sorbents and the "quick easy cheap effective rugged safe" extraction procedure to extract pesticides from bivalve matrices, as they appeared to be the most efficient while being the safest. Moreover, this method combined with the high-resolution mass spectrometry (MS) technique offers promising perspectives by highlighting a wide range of pesticides including those that are not usually sought. Finally, recent developments in the field of ultra-high-performance liquid chromatography coupled to MS, such as two-dimensional chromatography and ion mobility spectrometry, will improve the analysis of pesticides in complex matrices.

Hunt for Palytoxins in a Wide Variety of Marine Organisms Harvested in 2010 on the French Mediterranean Coast.

During the summer of 2010, 31 species including fish, echinoderms, gastropods, crustaceans, cephalopods and sponges were sampled in the Bay of Villefranche on the French Mediterranean coast and screened for the presence of PLTX-group toxins using the haemolytic assay. Liquid chromatography tandem mass spectrometry (LC-MS/MS) was used for confirmatory purposes and to determine the toxin profile. The mean toxin concentration in the whole flesh of all sampled marine organisms, determined using the lower- (LB) and upper-bound (UB) approach was 4.3 and 5.1 µg·kg(-1), respectively, with less than 1% of the results exceeding the European Food Safety Authority (EFSA) threshold of 30 µg·kg(-1)and the highest values being reported for sea urchins (107.6 and 108.0 µg·kg(-1)). Toxins accumulated almost exclusively in the digestive tube of the tested species, with the exception of octopus, in which there were detectable toxin amounts in the remaining tissues (RT). The mean toxin concentration in the RT of the sampled organisms (fishes, echinoderms and cephalopods) was 0.7 and 1.7 µg·kg(-1) (LB and UB, respectively), with a maximum value of 19.9 µg·kg(-1) for octopus RT. The herbivorous and omnivorous organisms were the most contaminated species, indicating that diet influences the contamination process, and the LC-MS/MS revealed that ovatoxin-a was the only toxin detected.

Method development and inter-laboratory comparison about the determination of titanium from titanium dioxide nanoparticles in tissues by inductively coupled plasma mass spectrometry.

Nanosized titanium dioxide (TiO2) is one of the most interesting and valuable nanomaterials for the construction industry but also in health care applications, food, and consumer goods, e.g., cosmetics. Therefore, the properties associated with this material are described in detail. Despite its widespread use, the analytical determination and characterization of nanosized metal oxides is not as straightforward as the comparatively easy-to-detect metallic nanoparticles (e.g., silver or gold). This study presents the method development and the results of the determination of tissue titanium (Ti) levels after treatment of rats with the nanosized TiO2. Total Ti levels were chosen to evaluate the presence and distribution of TiO2 nanoparticles. A procedure consisting of incubation with a mixture of nitric acid (HNO3) and hydrofluoric acid (HF), and heating was developed to digest tissues and TiO2 nanomaterials in order to determine the total Ti content by inductively coupled plasma mass spectrometry (ICPMS). For the inter-laboratory comparison, altogether four laboratories analyzed the same samples upon digestion using the available ICPMS equipment. A major premise for any toxicokinetic study is the possibility to detect the chemical under investigation in biological samples (tissues). So, the study has to be performed with a dose high enough to allow for subsequent tissue level measurement of the chemical under investigation. On the other hand, dose of the chemical applied should not induce over toxicity in the animal as this may affect its absorption, distribution, metabolism, and excretion. To determine a non-toxic TiO2 dosage, an acute toxicity study in rats was performed, and the organs obtained were evaluated for the presence of Ti by ICPMS. Despite the differences in methodology and independent of the sample preparation and the ICPMS equipment used, the results obtained for samples with Ti concentrations >4 µg Ti/g tissue agreed well.

Analysis of total microcystins by Lemieux oxidation and liquid chromatography-mass spectrometry in fish and mussels tissues: Optimization and comparison of protocols.

Microcystins (MCs) can be detected in various matrices in two forms: a freely extractable fraction and a total (free and covalently protein-bound) fraction. Although the majority of MCs analyses are limited to the free fraction, they do not allow the analysis of all MCs variants or protein-bound forms. Other methods, known as total MCs analysis methods, enable simultaneous analysis of all MCs variants, as well as bound forms, which may be a major form of toxin accumulation in organisms. Among these techniques, the chemical oxidation method (e.g. Lemieux) allows the detection of total forms of MC (and nodularins) by oxidizing the common part to all MC and nodularins, and analyzing the resultant MMPB product (2-methyl-3-methoxy-4-phenylbutyric acid). However, the execution of this method in the context of health monitoring is challenging due to the variability of the protocols, the recoveries obtained with these protocols, and the important matrix effects associated with the method. The objectives of this study were i) to optimize an existing protocol of chemical oxidation "Lemieux1" on fresh fish fillet matrices, ii) to compare two existing protocols ("Lemieux1" and "Lemieux2"), and iii) apply Lemieux oxidation to fish fillets and livers naturally contaminated with MCs-producing cyanobacteria and to freshwater mussels contaminated with MCs in laboratories. Optimization of the "Lemieux1" protocol, in particular in the oxidation and SPE (solid phase extraction) steps improved the method's yields on the fresh fish fillet matrix (from <5 % to around 40 %). Moreover, several quantification methods have been compared through various calibration techniques (solvent calibration curve, matrix-matched calibration curve, oxidized MC-LR calibration curve and also by testing the addition of d3-MMPB as an internal standard). Comparison with the "Lemieux2" protocol showed the best results on the same matrix, with yields of around 65 %. MMPB was analyzed using this "Lemieux 2" protocol, in livers of carps sampled during an episode of cyanobacteria proliferation, at concentrations ranging from 17.9 to 27.5 µg/kg MMPB and at concentrations ranging from 50 to 2890 µg/kg MMPB in freshwater mussels laboratory contaminated to MCs.

Fate of chlordecone during home cooking processes - Transfer into the liquid and aerial phases by conventional thermal processes.

This study focuses on the fate of chlordecone (CLD) during cooking processes. Neat CLD was subjected to thermogravimetric analysis, which revealed that the vast majority of the compound (79 %) was vaporised at temperatures between 55 and 245 °C. In order to monitor the behaviour of CLD during cooking processes, a QuEChERS extraction protocol was optimised for vegetable cooking oil and a heating kinetics experiment was conducted at 195 °C on CLD-spiked cooking oil. The results showed a strong decrease in CLD over time and, for the first time to our knowledge, transformation of CLD into chlordecol. Finally, a comparison was conducted between the cooking of uncured pork with and without vegetable oil. The use of vegetable oil led to a significant decrease in CLD content, but revealed that a fraction of the CLD transferred into the cooking oil. This study provides data that shed light on the fate of CLD during cooking.

Microwave-enhanced thermal removal of organochlorine pesticide (chlordecone) from contaminated soils.

Soil contamination with chlordecone, an organochlorine pesticide, is causing serious health problems, affecting crop production and local livestock valorization in the French West Indies. In-situ chemical reduction (ISCR) processes for soil remediation have shown promise but need improvement in terms of time, cost and effective treatment, particularly for andosol soil types. Our study shows that a 10-min microwave treatment significantly reduces chlordecone concentrations (50-90%) in contaminated andosol and nitisol soils. Dry andosol soils show the highest removal yields and reach a higher final temperature (350 °C). Microwave treatment is in all cases more effective or at least as effective as 60 min of conventional heating at a target temperature of 200 °C. The thermal response of andosol and nitisol to microwave exposure is different, as the former is likely to undergo thermal runaway, reaching high temperatures in a short time, resulting in highly efficient thermal removal of chlordecone. These results encourage further scale-up, particularly for the treatment of andosol soils due to their strong microwave response.

Optimization of an HPLC-MS/MS method to analyze chlordecone in bovine serum and correlations with levels in liver, muscle and fat.

Chlordecone is an organochlorine pesticide used from 1972 to 1993 in the French West Indies. Its extensive use and high persistence in soils induced massive contamination of the environment and of the food chain, especially in cattle through contaminated soil ingestion. To ensure suitability for consumption of bovine meat, monitoring plans are set up based on perirenal fat concentrations after slaughtering. In the present study, we have investigated an in-vivo monitoring approach by measuring chlordecone levels in serum samples. For this purpose, a sensitive high-performance liquid-chromatography-tandem mass spectrometry (HPLC-MS/MS) method following a QuEChERS extraction method was successfully optimized and validated, reaching a limit of quantification of 0.05 ng g-1 fresh weight. This method was applied to 121 serum samples collected from bovines originating from contaminated areas of Martinique and Guadeloupe. Chlordecone was detected in 88% of the samples, and quantified in 77% of the samples, with concentrations ranging from 0.05 to 22 ng g-1. Perirenal fat, liver, and muscle were also sampled on the same animals and the measured concentrations of chlordecone were statistically correlated to the levels determined in serum. Mean concentration ratios of 6.5 for fat/serum, 27.5 for liver/serum, and 3.3 for muscle/serum were calculated, meaning that chlordecone was not only distribute in fat (as expected), muscle and liver, but also in serum. Good correlations were found to allow prediction of chlordecone concentrations in muscle based on concentrations measured in serum. This study opens the door to possible pre-control of bovines before slaughter. In cases of probable non-compliance with maximum residue levels (MRLs), farm management could proceed to allow for depuration under controlled conditions. This would have a strong impact on both economic and food safety management measures.

Fate of chlordecone in soil food webs in a banana agroecosystem in Martinique.

Large quantities of chlordecone-based insecticides were produced and used throughout the world. One of its most important uses was to control the damage caused by Cosmopolites sordidus in banana-growing regions. In the islands of Martinique and Guadeloupe, 18,000 ha of farmland are potentially contaminated. Despite the key role played by soil macrofauna in agroecosystems, there are currently no data on their contamination. The aim of this study was to explore the fate of chlordecone (CLD) and its transfer to different organisms of the soil food web. Seven species of invertebrates representing different taxonomic groups and trophic levels of the soil communities of Martinique were targeted and collected in six experimental banana fields, with a level of contamination within a range of values classically observed. Soil samples and macrofauna from the study sites were analysed for CLD and chlordecol (CLDOH) its main transformation product. The contamination of the soil fauna were related to δ15N (trophic level), proportion of soil ingestion (diet) and types of epidermis (mucus or exoskeleton) in order to study the different mechanisms of macrofauna contamination. Presence of CLD and CLDOH could be quantified in all the soil organisms from contaminated fields. Results showed a significant relationship between the CLD contamination of detritivorous and the ash content of their faeces, suggesting that soil ingestion was the main contamination pathway. In contrast, the exoskeleton-bearing diplopod Trigoniulus coralinus and the soft-bodied earthworm Eudrilus eugeniae, both detritivores with a comparable diet, had similar contamination levels, suggesting that the type of tegument has little influence on bioaccumulation. At the scale of the entire trophic network, a significant relationship was uncovered between δ15N values and CLD contamination of the fauna, therefore providing some in situ evidence for a bioamplification process along the soil food chain.

Innovative analytical methodologies for characterizing chemical exposure with a view to next-generation risk assessment.

The chemical burden on the environment and human population is increasing. Consequently, regulatory risk assessment must keep pace to manage, reduce, and prevent adverse impacts on human and environmental health associated with hazardous chemicals. Surveillance of chemicals of known, emerging, or potential future concern, entering the environment-food-human continuum is needed to document the reality of risks posed by chemicals on ecosystem and human health from a one health perspective, feed into early warning systems and support public policies for exposure mitigation provisions and safe and sustainable by design strategies. The use of less-conventional sampling strategies and integration of full-scan, high-resolution mass spectrometry and effect-directed analysis in environmental and human monitoring programmes have the potential to enhance the screening and identification of a wider range of chemicals of known, emerging or potential future concern. Here, we outline the key needs and recommendations identified within the European Partnership for Assessment of Risks from Chemicals (PARC) project for leveraging these innovative methodologies to support the development of next-generation chemical risk assessment.

Trace elements and arsenic speciation in Paracentrotus lividus from North-West Mediterranean Sea.

Levels of 14 trace elements (Al, Ti, V, Cr, Mn, Co, Ni, Zn, As, Se, Cd, Sn, Hg, and Pb) and 5 arsenic species (arsenite/As(III), arsenate/As(V), monomethylarsonic acid/MA, dimethylarsinic acid/DMA, and arsenobetaine/AsB) were assessed in the gonads of sea urchin samples (Paracentrotus lividus) from North-West Mediterranean Sea (French coast). The samples were collected from 13 sites characterized by different types and levels of chemical contamination. Trace elements levels were measured by inductively coupled plasma-mass spectrometry (ICP-MS) following microwave (acid) digestion in a closed system, whereas As speciation analysis was carried out by ion-exchange liquid chromatography coupled with ICP-MS after microwave-assisted extraction. High levels of trace elements were found in sea urchins sampled from Corsica whereas the samples from Théoule were found to be the least contaminated. From all the analyzed urchin samples, none showed Cd, Hg, or Pb concentrations above the regulatory levels set by the European Community (EC) No. 1881/2006 for seafood or bivalve mollusks. Regarding arsenic speciation, AsB was confirmed to be the predominant species. Inorganic As (As(III) + As(V)) was mainly constituted by As(III), which was quantified in all samples. Methylated As forms (MA and DMA) represent 9 to 23% of the total As.

Optimisation and implementation of QuEChERS-based sample preparation for identification and semi-quantification of 694 targeted contaminants in honey, jam, jelly, and syrup by UHPLC-Q/ToF high-resolution mass spectrometry.

A screening and semi-quantitative method was developed for the analysis of 694 various contaminants in honey, jam, jelly and syrup samples by ultrahigh-performance liquid chromatography and quadrupole time-of-flight mass spectrometry. Sample preparation, which was optimised using split factorial design, was based on acetate-buffered version of QuEChERS, followed by a clean-up step and a concentration step to enhance sensitivity of analytes. The method was validated according to SANTE/11312/2021 guidelines. The screening detection and limits of identification were established as being less than or equal to 0.05 mg.kg-1 for 89% and 74% of the contaminants, respectively. The validated screening method was applied to 50 concentrated sugary products. Overall, 46% of the samples were positive to pesticide residues. Most of the positive samples (78%) contained mixtures of pesticide residues. Three time-and-cost saving convenient strategies suitable for high-throughput analysis were proposed for the targeted semi-quantification of the previously contaminants identified in samples.

Wide-scope screening of multi-class contaminants in seafood using a novel sample preparation (QuEChUP) procedure coupled with UHPLC-Q-TOF-MS: Application for semi-quantitation of real seafood samples.

A high-resolution mass spectrometry screening method was developed and validated based on EU SANTE/11312/2021 guidelines for the analysis of 850 multi-class contaminants in commercial seafood samples. Samples were extracted using a novel sequential QuEChUP preparation method that combines the QuEChERS and QuPPe procedures. The screening detection limits (SDLs) and limits of identification (LOIs) were equal to or lower than 0.01 mg·kg-1 for 92% and 78% of contaminants, respectively. This screening procedure was ultimately applied for a target screening analysis of 24 seafood samples. The concentrations of identified contaminants were assessed using semi-quantitative approach. Two identified contaminants, diuron and diclofenac, showed the highest estimated average concentrations: 0.076 and 0.068 mg·kg-1 respectively in mussel samples. Suspect screening was also performed. Target and suspect screening led to the identification of mixtures of contaminants (pesticides, veterinary products, industrial chemicals and personal care products) and the assessment of their frequencies of appearance (FoA).

Seasonal variations of low pesticides contamination and biomarker responses in marine bivalves from French estuaries.

Biomarkers involved in detoxification process (GST), oxidative stress (SOD and MDA), immune response (Laccase) and neurotoxic disorders (AChE) were analysed in Pacific oysters and blue mussels collected from 4 locations within the Pertuis sea (France). Seasonal variations of total pesticide mean concentrations were found in seawater with metolachlor being the main pesticide measured (up to 32 ng/L). The majority of pesticide concentrations in sediment were below the LOD. Seasonal contamination differences were evidenced for chlortoluron, especially in mussels where concentrations reached 16 ng/g (wet weight) during the winter, in the Charente estuary, but no relationships with any of the biomarkers selected arisen. Actually, low concentrations of alpha-, beta-BHC and alachlor were correlated to GST activity, and low levels of hexachlorobenzene were linked to the AChE activity and MDA content in oysters. In mussels, low concentrations of methylparathion, parathion and beta-BHC were correlated to laccase.

Assessment of Differentiated Thyroid Carcinomas in French Polynesia After Atmospheric Nuclear Tests Performed by France.

Importance: Due to the amount of iodine 131 released in nuclear tests and its active uptake by the thyroid, differentiated thyroid carcinoma (DTC) is the most serious health risk for the population living near sites of nuclear tests. Whether low doses to the thyroid from nuclear fallout are associated with increased risk of thyroid cancer remains a controversial issue in medicine and public health, and a misunderstanding of this issue may be associated with overdiagnosis of DTCs. Design, Setting, and Participants: This case-control study was conducted by extending a case-control study published in 2010 that included DTCs diagnosed between 1984 and 2003 by adding DTCs diagnosed between 2004 and 2016 and improving the dose assessment methodology. Data on 41 atmospheric nuclear tests conducted by France between 1966 and 1974 in French Polynesia (FP) were assessed from original internal radiation-protection reports, which the French military declassified in 2013 and which included measurements in soil, air, water, milk, and food in all FP archipelagos. These original reports led to an upward reassessment of the nuclear fallout from the tests and a doubling of estimates of the mean thyroid radiation dose received by inhabitants from 2 mGy to nearly 5 mGy. Included patients were diagnosed from 1984 to 2016 with DTC at age 55 years or younger and were born in and resided in FP at diagnosis; 395 of 457 eligible cases were included, and up to 2 controls per case nearest by birthdate and matched on sex were identified from the FP birth registry. Data were analyzed from March 2019 through October 2021. Exposure: The radiation dose to the thyroid gland was estimated using recently declassified original radiation-protection service reports, meteorological reports, self-reported lifestyle information, and group interviews of key informants and female individuals who had children at the time of these tests. Main Outcomes and Measures: The lifetime risk of DTC based on Biological Effects of Ionizing Radiation (BEIR) VII models was estimated. Results: A total of 395 DTC cases (336 females [85.1%]; mean [SD] age at end of follow-up, 43.6 [12.9] years) and 555 controls (473 females [85.2%]; mean [SD] age at end of follow-up, 42.3 [12.5] years) were included. No association was found between thyroid radiation dose received before age 15 years and risk of DTC (excess relative risk [ERR] per milligray, 0.04; 95% CI, -0.09 to 0.17; P = .27). When excluding unifocal noninvasive microcarcinomas, the dose response was significant (ERR per milligray, 0.09; 95% CI, -0.03 to 0.02; P = .02), but several incoherencies with the results of the initial study reduce the credibility of this result. The lifetime risk for the entire FP population was 29 cases of DTC (95% CI, 8-97 cases), or 2.3% (95% CI, 0.6%-7.7%) of 1524 sporadic DTC cases in this population. Conclusions and Relevance: This case-control study found that French nuclear tests were associated with an increase in lifetime risk of PTC in FP residents of 29 cases of PTC. This finding suggests that the number of thyroid cancer cases and the true order of magnitude of health outcomes associated with these nuclear tests were small, which may reassure populations of this Pacific territory.

Bioaccessibility of total arsenic and arsenic species in seafood as determined by a continuous online leaching method.

A continuous leaching method coupled online with inductively coupled plasma mass spectrometry (ICP-MS) detection was used to assess the maximum bioaccessibility of arsenic (As) in seafood samples. The method simulates continuous-flow digestion by successively pumping artificial saliva, gastric and intestinal juices through a mini-column of powdered sample directly connected to the nebuliser of an ICP-MS instrument. The method allows the real-time measurement of As being released by a given reagent. Because the analyte is continuously removed from the system, in contrast to batch methods, the dissolution equilibrium is driven to the right, hence quickly providing information about the worst-case scenario. Following consecutive leaching by the digestive reagents, the leachates were subject to speciation analysis by ion-exchange chromatography with ICP-MS detection to determine the arsenic species released. Finally, the remaining residue from the mini-column was fully digested to verify mass balance. The method was used to determine the bioaccessibility of total As and As species in four certified reference materials and in several real seafood samples. The mass balance was verified in each case. Generally speaking, the non-toxic form was easily released whereas the inorganic forms were poorly bioaccessible.

Improving the monitoring of multi-class pesticides in baby foods using QuEChERS-UHPLC-Q-TOF with automated identification based on MS/MS similarity algorithms.

A screening method was developed for the multi-residue analysis of pesticides in baby foods using QuEChERS and UHPLC-Q-TOF. For sample preparation, the two-buffered versions of QuEChERS and different purification procedures were studied. False negatives and false positives were determined using different thresholds mentioned in the literature on the retention time and accurate mass measurement detection criteria. To reach unequivocal identification, the fragmentation spectra of the pesticides were used. The information-dependant-acquisition (IDA) mode was optimized with a precursor-inclusion list (PIL) to limit the loss of MS/MS data. Then, the experimental fragmentation spectra were compared to those included in a homemade library, by assessing different MS/MS algorithms and similarity scores. The optimised method was validated according to SANTE/11312/2021 guidelines. 95% and 73% of the pesticides presented a screening detection limit (SDL) and a limit of identification (LOI) ≤ 0.1 mg.kg-1. One plasticizer was found in the investigated samples by a suspect-screening approach.

Analysis of Total-Forms of Cyanotoxins Microcystins in Biological Matrices: A Methodological Review.

Microcystins (MCs) are cyclic heptapeptidic toxins produced by many cyanobacteria. Microcystins can be accumulated in various matrices in two forms: a free cellular fraction and a covalently protein-bound form. To detect and quantify the concentration of microcystins, a panel of techniques on various matrices (water, sediments, and animal tissues) is available. The analysis of MCs can concern the free or the total (free plus covalently bound) fractions. Free-form analyses of MCs are the most common and easiest to detect, whereas total-form analyses are much less frequent and more complex to achieve. The objective of this review is to summarize the different methods of extraction and analysis that have been developed for total forms. Four extraction methods were identified: MMPB (2-methyl-3-methoxy-4-phenylbutyric acid) method, deconjugation at basic pH, ozonolysis, and laser irradiation desorption. The study of the bibliography on the methods of extraction and analysis of the total forms of MCs showed that the reference method for the subject remains the MMPB method even if alternative methods and, in particular, deconjugation at basic pH, showed results encouraging the continuation of the methodological development on different matrices and on naturally-contaminated samples.

Development and validation according to the SANTE guidelines of a QuEChERS-UHPLC-QTOF-MS method for the screening of 204 pesticides in bivalves.

A qualitative screening high resolution mass spectrometry method was developed and validated according to the EU SANTE/12682/2019 guidelines for the analysis of 204 pesticides in seven commercial bivalve species spiked at three concentrations (0.01, 0.05 and, 0.1 mg.kg-1). Samples were extracted using QuEChERS and analysed using ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. The QuEChERS method was optimised by the Taguchi Orthogonal Array approach. The best conditions were obtained with pure ACN, MgSO4/NaCl as extraction salts, MgSO4/PSA/C18 as clean-up, and the non-dilution of extracts. The impact of different HRMS acquisition modes on detection and identification rates were also evaluated. The screening detection limits were determined to be 0.01 mg.kg-1 and 0.1 for 66% and 87% of pesticides, respectively. These screening procedure was finally applied to different bivalve samples using target and suspect analysis. This allowed the identification of diuron and its metabolite 1-(3,4-dichlorophenyl)-3-methylurea in the investigated samples.

Probabilistic determination of a maximum acceptable level of contaminant to reduce the risk of overexposure for a novel or emerging food: the case of cadmium in edible seaweed in the French population.

European and French populations are overexposed to cadmium (Cd) through their foods. The risk of increased cadmium exposure for consumers needs to be limited by reduced maximum limits (ML) for novel foodstuffs such as edible seaweed in France. The objective was to derive a low and protective cadmium concentration in edible seaweeds to limit cadmium overexposure in consumers. To do so, we applied a probabilistic approach to the data collected on French seaweed consumers, taking into account other sources of exposure for cadmium. This approach led to the identification of a cadmium concentration which should ensure that the seaweed-consuming population does not exceed the tolerable daily intake (TDI) of cadmium according to a probability of cases, when simultaneously exposed to other cadmium dietary sources. Considering the 5% of the population exceeding TDI, the estimated ML is equal to 0.35 mg Cd kg-1 dry matter of seaweed as an unprocessed food with a 95% confidence interval of [0.18,1.09]. The proposed approach is generic and could be applied to other relevant food/substance pairs when considering the setting of MLs in the regulatory system. It ensures better protection of consumer health.