Fillets from a total of 1245 Northeast Atlantic mackerel (Scomber scombrus) sampled in different fishing areas of the Northeast Atlantic during 2007-2016 were analysed for mercury, cadmium, arsenic and lead using ICPMS. Mercury levels varied from <0.01 to 0.36 mg/kg wet weight (ww) with a total mean of 0.046 mg/kg ww and were significantly higher in Skagerrak than in the North Sea, the Norwegian Sea and west of Scotland. Cadmium concentrations varied from <0.002 to 0.16 mg/kg ww with a mean value of 0.015 mg/kg ww. Only 0.24 % and 0.16 % of the sampled fish exceeded the EU's maximum levels for cadmium and mercury, respectively. Arsenic levels varied between 0.43 and 6.9 mg/kg ww with a mean value of 2.2 mg/kg ww and showed seasonal variation following variations in fat content. Lead concentrations were low and below the analytical limit of quantification (LOQ) in 97 % of the samples.

Organotin compounds are anthropogenic metal species with multiple uses as pesticides, preservatives, antifouling agents, biocides, and catalysts. Butyltins are the main organotin compounds found in biota, and the highest levels are found in marine foodstuffs. In this paper, we present the figures of merit for an in-house validated method for routine analysis of butyltins in seafood using GC inductively coupled plasma isotope dilution MS. The working range of the method spanned several orders of magnitude from 3.3-1013, 2.4-785, and 0.3-900 ng Sn/g dry weight for monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT), respectively. The trueness of the method was evaluated by analyzing Certified Reference Materials (CRMs) ERM CRM 477 (Mussel Tissue) and NIES CRM 15 (Scallop). Recoveries, with RSD % in parentheses, were 78 (±14), 80 (±6), and 88% (±8%) for MBT, DBT, and TBT in ERM CRM 477 and 96% (±5%) for TBT in NIES CRM 15. Good agreements were found between experimental uncertainties and uncertainties predicted for single-laboratory validated methods calculated from the maximum standard measurement uncertainty function. The method has proven to be robust, and the wide range of seafood validated ensures that the method is applicable for measuring butyltins in marine tissue.

The aims of this study were to (1) determine any changes in the levels of persistent organic pollutants (POP) and mercury (Hg) in human plasma and adipose tissue and (2) examine associations between plasma levels of pollutants and dietary fat intake. Outpatients with different metabolic disorders (n = 42) consumed 380 g of farmed Atlantic salmon fillets or 60 g of salmon oil per week in two study periods of 15 wk each, and were compared with a control group (n = 14). Concentrations of POP and Hg were measured in salmon fillets, salmon oil capsules, plasma and abdominal fat biopsies from patients before and after intervention. Mean concentrations of hexachlorobenzene (HCB), p, p'-DDE, sum of indicator polychlorinated biphenyls (PCB) (id-PCB), and sum polybrominated diphenyl ethers (PBDE) in abdominal fat at intervention start were 21, 191, 267, and 4.2 ng/g lipid weight. After 15 or 30 wk of salmon consumption no significant changes in concentrations of POP and Hg in samples of human plasma and abdominal fat were observed, indicating that steady-state levels of these pollutants were not markedly affected. The lack of significant changes may partly be attributed to a limited number of samples, large interindividual variation in POP levels, and a large age span (20-70 yr). After adjusting for age, significant associations were found between different plasma long-chain fatty acid concentrations, including n-3 and n-6 fatty acids and oleic acid, and some of the POP. The results indicate that the latter have different food products as their main sources of human exposure.

BACKGROUND:Environmental pollutants such as dioxins and PCBs, heavy metals, and organochlorine pesticides are a global threat to food safety. In particular, the aquatic biota can bioaccumulate many of these contaminants potentially making seafood of concern for chronic exposure to humans. OBJECTIVES:The main objective was to evaluate trends of contaminant levels in Norwegian farmed Atlantic salmon in light of the derived tolerable intakes. METHODS:Through an EU-instigated surveillance programme, the Norwegian Food Safety Authority (NFSA) has between 1999 and 2011 collected more than 2300 samples of Norwegian farmed Atlantic salmon (Salmo salar) for contaminant analyses. The fillets of these fish were homogenised and analysed for dioxins, PCBs, heavy metals and organochlorine pesticides. RESULTS:The levels of the contaminants mercury, arsenic, dioxins, dioxin-like PCBs and DDT in Norwegian farmed salmon fillet have decreased during our period of analyses. The levels of cadmium, lead and several organochlorine pesticides were too close to the limit of quantification to calculate time trends. For PCB6 and quantifiable amounts of pesticides, except DDT, stable levels were observed. CONCLUSION:The contaminant levels in Norwegian farmed salmon have generally decreased between 1999 and 2011. Excluding other dietary sources, the levels of dioxins and dioxin-like PCBs in 2011 allowed consumption of up to 1.3kg salmon per week to reach the tolerable weekly intake. The group of contaminants which was the limiting factor for safe consumption of Norwegian farmed salmon, based on currently established TWI values, is the sum of dioxins and dioxin-like PCBs.

Currently, there is no legal limit for methyl mercury (MeHg) in food; thus, no standardized method for the determination of MeHg in seafood exists within the European jurisdiction. In anticipation of a future legislative limit an inductively coupled plasma isotope dilution mass spectrometry (GC-ICP-ID-MS) method was developed in collaboration with the European Standardization Organization (CEN). The method comprises spiking the tissue sample with Me201Hg, followed by decomposition with tetramethylammonium hydroxide, pH adjustment and derivatization with sodium tetraethylborate, and finally organic extraction of the derivatized MeHg in a hexane phase. Subsequently, the sample is analyzed via GC-ICP-MS and the result calculated using the ID equation. The working range of the method was 0.0005-1.321 mg/kg MeHg in marine tissue, with an internal reproducibility (RSD) of 12-1%. The method was validated based on statistical measures, such as the z-scores, using the commercially available reference materials from National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1566b, NIST SRM 2977 and National Research Council of Canada (NRCC) TORT 2, NRCC, DORM 3, NRCC DOLT 4, and European Reference Material (ERM) CE 464. Z-scores for all standard reference materials, except for NIST SRM 1566b, were better than 11.51. The wide range of marine tissues used during the validation ensures that the method will be applicable for measuring of MeHg in seafood matrixes of all kinds.

The tusk (Brosme brosme) is a popular gadoid fish for human consumption, which also is susceptible to mercury accumulation. However, few data of mercury levels in tusk exist, and it is difficult to compare tusk fished from assumed contaminated areas with background levels. The aim of this study was to increase the information of mercury levels observed in tusk from the Northeast Atlantic Ocean. Samples of tusk were collected from seven different localities in open ocean areas, nine along the Norwegian coastal current (NCC), and from two fjord stations. Determinations of mercury in muscle and liver were carried out using inductive coupled plasma mass spectrometry (ICPMS) after microwave-assisted wet digestion. The highest concentrations of mercury in muscle were found in tusk captured from the fjords Hardangerfjord and Sorfjord, and had mean concentrations of mercury at 1.5 and 1.7 mg kg -1 wet weight (ww), respectively, where all of the tusk exceeded EU's upper limit of 0.5 mg kg -1 ww. The lowest concentrations of mercury were observed in tusk captured from the open ocean areas, and the concentrations ranged from 0.08 to 0.30 mg kg -1 ww. Mercury concentrations of tusk captured along the NCC ranged from 0.21 to 0.49 mg kg -1 ww. Mercury concentrations increased with the weight of the tusk, and variance analysis (ANOVA) of weight normalized mercury concentrations showed that there were significant differences in mercury concentrations between tusk collected from the open ocean, NCC and fjords, which indicates that differences in mercury concentration between different areas arecaused by other factors.

The aim of this study was to examine Peruvian anchovy oil fatty acid (FA) compositions, and to test the possibility of using the FA data to classify the oils according to geographical origin along the Peruvian coast. The levels of contaminants in a representative set of samples were determined to examine the general levels and investigate if such measurements could aid in future discrimination between oils. The FA results showed that the two known stocks of Peruvian anchovy displayed different levels of docosahexaenoic acid (DHA, 22:6n-3) (southern stock; 14.4 ± 0.8% versus central-northern stock; 9.9 ± 1.2%). However, principal component analysis (PCA) of the FA data indicated clusters according to three regions; North, Center and South. Using a data set of 57 anchovy samples and 21 FA as input, a probabilistic neural network (PNN) was constructed. For the validation data sets, “North” oils was predicted accurately 100% of the time, “Center” oils 100% and “South” oils 83% of the time. The levels of contaminants in the oils determined were low in all but one sample.

ContextDental and skeletal fluorosis is endemic in the Ethiopian Rift Valley. Children are especially vulnerable to excessive fluoride intake because their permanent teeth are still being formed. Strategies to reduce the total fluoride intake by children are thus warranted.Case presentationBy combining the results of field studies in Ethiopia, the relevant pathways for fluoride intake have been identified in 28 children 2–5 years of age living in two villages on the Wonji Shoa Sugar Estate in the Ethiopian Rift Valley. The focus of the present study was to simulate the fluoride intake of the children using the methods of material flow analysis (MFA) and substance flow analysis.DiscussionWith a model based on MFA, we quantified the potential reduction in total fluoride intake given different scenarios—for example, by reducing the fluoride intake from drinking water and cooking water. The results show clearly that only by removing fluoride completely from both drinking and cooking water does the probability of remaining below the daily tolerable upper intake level exceed 50%. Both prepared food and food ingredients must be taken into consideration when assessing the total fluoride intake by children living in high-fluoride areas.RelevanceThis knowledge will help health personnel, the government, and the food authorities to give scientifically based advice on strategies for reducing the total fluoride intake by children living in high-fluoride areas in the Ethiopian Rift Valley.

The Norwegian spring spawning (NSS) herring is an ecologically important fish stock in the Norwegian Sea, and with a catch volume exceeding one million tons a year it is also economically important and a valuable food source. In order to provide a baseline of the levels of contaminants in this fish stock, the levels of organohalogen compounds were determined in 800 individual herring sampled at 29 positions in the Norwegian Sea and off the coast of Norway. Due to seasonal migration, the herring were sampled where they were located during the different seasons. Concentrations of dioxins and dioxin-like PCBs, non-dioxin-like PCBs (PCB7) and PBDEs were determined in fillet samples of individual herring, and found to be relatively low, with means (min–max) of 0.77 (0.24–3.5) ngTEQkg−1 wet weight (ww), 5.0 (1.4–24) μgkg−1 ww and 0.47 (0.091–3.1) μgkg−1 ww, respectively. The concentrations varied throughout the year due to the feeding- and spawning cycle: Starved, pre-spawning herring caught off the Norwegian coast in January–February had the highest levels and those caught in the Norwegian Sea in April–June, after further starvation and spawning, had the lowest levels. These results show that the concentrations of organohalogen compounds in NSS herring are relatively low and closely tied to their physiological condition, and that in the future regular monitoring of NSS herring should be made in the spawning areas off the Norwegian coast in late winter.

Seawater adapted Atlantic salmon post-smolts were fed graded levels of technical endosulfan (0.005, 0.05, and 1mgkg−1) for 16weeks. Markers of endocrine disruption (plasma vitellogenin, and plasma sex steroid-binding proteins) and oxidative stress (hepatic glutathione peroxidase activity, and α-tocopherol level) were not affected by dietary concentrations used in this study. Adaptive responses such as biotransformation (hepatic 7-ethoxyresorufin-O-deethylase EROD activity) was significantly induced at the lowest and second lowest exposure levels (0.005 and 0.05mgkg−1), but not at the highest exposure levels. Adverse effects such as significantly increased hepatic somatic index was observed in the 1mgkg−1 exposure group, however, apparent markers of liver damage (plasma aspartate aminotransferase and alanine aminotransferase level, or liver histopathological necrosis) were absent. The relative amount (%) of red pulp in spleen significantly increased in fish fed 0.005 and 0.05mgkg−1 whereas haematology (e.g. blood erythrocyte count and haemoglobin) remained similar to that of the control group. Levels of 0.005 and 0.05mgkg−1 did not cause overall adverse effects, whereas levels of 1mgkg−1 caused adverse effects as seen from a lacking hepatic biotransformation (EROD) activity and increased hepatic somatic index. Histological changes such as areas of vacuolization and fusion of villi in the intestine at lowest exposure levels warrant further investigation on the effects of dietary endosulfan exposure on nutritional performance and growth.

In the present study, duplicate diets ( four-day survey) of 28 Ethiopian children were analysed for iron, zinc and iodine. The mothers of the children filled out a food frequency questionnaire describing general intake of local food ingredients. The average daily intake of zinc was found to be 5.7 +/- 5.2 mg, while the daily intake of iron and iodine was 52 +/- 43 mg and 0.13 +/- 0.10 mg, respectively. Most of the investigated children had an adequate nutrient intake of zinc and iodine, while the intake of iron was high compared to international recommendations. There was a great individual variation in intake of these trace elements, and even though the mean and median values were above or in the range of the requirement, some children had a too low intake of zinc and iodine. The iron intake varied the most, and was generally high. The diet was cereal based and contained little fruit and food of animal origin which may reduce the availability of iron and zinc.

Marine feed ingredients, traditionally used in commercial fish feeds, are the source of these pollutants in farmed fish. The aim of the study was to assess the chemical contaminant load in Atlantic salmon (Salmo salar L.) raised on novel sustainable feeds based on a combination of alternative ingredients. Atlantic salmon were reared on feeds based on either traditional or alternative feed ingredients for an entire seawater production cycle up to approximately 4kg, which is a typical market-size for this species. The levels of several notorious contaminants were analysed in feed ingredients, feed, and skin-off fillets. These included persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs), dioxins and furans (PCDD/Fs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs), as well as elements such as arsenic, mercury, cadmium, lead, copper, zinc and fluorine. In addition, poly-aromatic hydrocarbons (PAHs) were analysed. The use of alternative feed ingredients reduced the fillet load of POPs by 51–82% and the level of arsenic and mercury by 80–96%. In contrast, the PAH levels in fish reared on the novel feeds were significantly (p<0.05) higher than the PAH concentrations in traditionally-raised fish. The present study shows that developments in feed formulation will reduce the load of most persistent organic pollutants in farmed salmon, but may increase concentrations of other contaminants such as PAHs, which are normally not associated with Atlantic salmon. The paper also compares the levels of contaminants in farmed Atlantic salmon expected in the future with those levels reported in the literature and currently on the market.

In this study, the stability of arsenic compounds in fresh and frozen samples of raw, boiled and fried Atlantic cod (Gadhus morhua), Atlantic salmon (Salmo salar) and blue mussel (Mytilus edulis) were examined. Results show that the total arsenic concentrations of the fresh Atlantic cod and Atlantic salmon samples were not different from the frozen samples within the same seafood type. For blue mussel, the total arsenic concentration decreased significantly after storage. Inorganic arsenic was found only in blue mussels and, importantly, no significant increase of inorganic arsenic was observed after processing or after storage by freezing. The content of tetramethylarsonium ion was generally low in all samples types, but increased significantly in all fried samples of both fresh and frozen seafood. Upon storage by freezing, the arsenobetaine content was reduced significantly, but only in the samples of blue mussels.

The present study reports the findings of unusual high levels of inorganic arsenic in samples of blue mussels (Mytilus edulis L.). A total of 175 pooled samples of blue mussels from various locations along the Norwegian coastline were analyzed for their content of total arsenic and inorganic arsenic. Total arsenic was determined using inductively coupled plasma mass spectrometry (ICPMS) following microwave-assisted acidic digestion of the samples. Inorganic arsenic was determined using an anion-exchange HPLC-ICPMS method following microwave-assisted alkaline solubilization of the samples. For the majority of the samples (78%) the concentration of total arsenic was below 3 mg kg(-1) wet weight (ww) and inorganic arsenic constituted <9% of the total arsenic (i.e., <0.25 mg kg(-1) ww). However, in some samples higher concentrations of total arsenic were found (up to 13.8 mg kg(-1) ww) and the inorganic arsenic content constituted up to 42% of the total arsenic (up to 5.8 mg kg(-1) ww). These are among the highest inorganic arsenic concentrations reported so far for marine animals. The findings of samples with concentrations of inorganic arsenic above 0.53 mg kg(-1) ww were restricted to sampling sites from two counties, Sogn and Fjordane and Hordaland, whereas samples from the rest of the country showed lower inorganic arsenic concentrations. Consumption of a meal containing 200 g of the blue mussels with the highest content of inorganic arsenic would for a 70 kg person lead to a 10% excess of the provisional tolerable weekly intake (PTWI) value for inorganic arsenic of 15 microg kg(-1) of body weight week(-1).

Answer to Q1: The Norwegian Scientific Committee for Food Safety, Panel of nutrition, dietetic products, novel food and allergy, refers to work done by the Food Standards Agency, UK , (http://www.food.gov.uk/) and elaborated by the Danish Institute of Food and Veterinary Research. We acknowledge their suggestions for (Temporary) Guidance Levels where upper levels have not been established by the Scientific Committee on Food (SCF).