A screening study of relationships among concentrations of algal toxins, PFAS, thiamine deficiency and biomarkers in the European flounder from the southern Baltic Sea

In the disturbed Baltic Sea ecosystem, several animal species display failing health related to exposure to toxic compounds, reduced energy metabolism and immune system disorders. In order to investigate possible associations between fish health and exposure to chemicals affecting the energy metabolism and immune defence, the levels of algal toxins (bromophenols, hydroxylated polybrominated diphenyl ethers and nodularin), perfluorinated alkyl substances (PFAS) and thiamine (vitamin B1) were determined in European flounder (Platichthys flesus). Several biomarkers indicating health status were examined in the fish, including ethoxyresorufin-O-deethylase (EROD), and activities of glutathione reductase, glutathione S-transferase and catalase, in addition to a large set of blood variables. The fish were collected from Hanobukten in the south-western parts of the Baltic Sea in late August 2018. Regression analyses of algal toxins, PFAS and thiamine concentration displayed several significant associations with biomarkers associated with detoxification and liver function, immune system function and blood status of the fish. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Severe thiamine deficiency in eastern Baltic cod (Gadus morhua)

The eastern Baltic cod (Gadus morhua) population has been decreasing in the Baltic Sea for at least 30 years. Condition indices of the Baltic cod have decreased, and previous studies have suggested that this might be due to overfishing, predation, lower dissolved oxygen or changes in salinity. However, numerous studies from the Baltic Sea have demonstrated an ongoing thiamine deficiency in several animal classes, both invertebrates and vertebrates. The thiamine status of the eastern Baltic cod was investigated to determine if thiamine deficiency might be a factor in ongoing population declines. Thiamine concentrations were determined by chemical analyses of thiamine, thiamine monophosphate and thiamine diphosphate (combined SumT) in the liver using high performance liquid chromatography. Biochemical analyses measured the activity of the thiamine diphosphate-dependent enzyme transketolase to determine the proportion of apoenzymes in both liver and brain tissue. These biochemical analyses showed that 77% of the cod were thiamine deficient in the liver, of which 13% had a severe thiamine deficiency (i.e. 25% transketolase enzymes lacked thiamine diphosphate). The brain tissue of 77% of the cod showed thiamine deficiency, of which 64% showed severe thiamine deficiency. The thiamine deficiency biomarkers were investigated to find correlations to different biological parameters, such as length, weight, otolith weight, age (annuli counting) and different organ weights. The results suggested that thiamine deficiency increased with age. The SumT concentration ranged between 2.4-24 nmol/g in the liver, where the specimens with heavier otoliths had lower values of SumT (P = 0.0031). Of the cod sampled, only 2% of the specimens had a Fulton's condition factor indicating a healthy specimen, and 49% had a condition factor below 0.8, indicating poor health status. These results, showing a severe thiamine deficiency in eastern Baltic cod from the only known area where spawning presently occurs for this species, are of grave concern

Biomarkers in Natural Fish Populations Indicate Adverse Biological Effects of Offshore Oil Production

Despite the growing awareness of the necessity of a sustainable development, the global economy continues to depend largely on the consumption of non-renewable energy resources. One such energy resource is fossil oil extracted from the seabed at offshore oil platforms. This type of oil production causes continuous environmental pollution from drilling waste, discharge of large amounts of produced water, and accidental spills.Samples from natural populations of haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua) in two North Sea areas with extensive oil production were investigated. Exposure to and uptake of polycyclic aromatic hydrocarbons (PAHs) were demonstrated, and biomarker analyses revealed adverse biological effects, including induction of biotransformation enzymes, oxidative stress, altered fatty acid composition, and genotoxicity. Genotoxicity was reflected by a hepatic DNA adduct pattern typical for exposure to a mixture of PAHs. Control material was collected from a North Sea area without oil production and from remote Icelandic waters. The difference between the two control areas indicates significant background pollution in the North Sea.It is most remarkable to obtain biomarker responses in natural fish populations in the open sea that are similar to the biomarker responses in fish from highly polluted areas close to a point source. Risk assessment of various threats to the marine fish populations in the North Sea, such as overfishing, global warming, and eutrophication, should also take into account the ecologically relevant impact of offshore oil production

Condition monitoring in the water column 2005: Oil hydrocarbons in fish from Norwegian waters

This report has been prepared by Institute of Marine Research (IMR) & University of Stockholm (UoS) on behalf on the offshore petroleum industry operators on the Norwegian Continental Shelf as part of the authority requirements in the Health, Safety and Environmental regulation (Activity regulation). The objectives for this study have been: 1. Determine to what extent fish from the oil installation areas at Tampen and the Halten Bank contain elevated levels of petroleum hydrocarbons compared with fish from reference areas at the Egersund Bank/Ling Bank and in the Barents Sea by measurements of NPD/PAH in fish muscle. 2. Comparison of NPD/PAH bile metabolites in fish from Tampen compared with fish from Egersund Bank/Ling Bank 3. Study possible genototoxic effects in fish from Tampen compared with fish from Egersund Bank/Ling Bank by measurements of hepatic DNA adducts. 4. Document to what extent discharges of alkylphenols in produced water cause estrogenic effects in fish from Tampen by measurements of alkylphenols in muscle and liver, and vitellogenin in plasma. Di- and polyaromatic hydrocarbons (NPD/PAH) have been analysed in muscle of cod and haddock caught in the North Sea at Ling Bank/Egersund Bank (reference), Tampen, Halten Bank and Barents Sea (reference), autumn 2005 and concentrations found to be below levels of quantification (LOQ) for fish sampled from all regions. Cod sampled at the Ling Bank/Egersund Bank in the Southern part of the North Sea had the same levels of PAH metabolites in bile as cod sampled from the Tampen region. Haddock demonstrated significantly higher levels of fluorescence for all three wavelength pairs measured, indicating a higher levels of 2-, 3-, 4- and 5-ring PAHs for haddock sampled in the Tampen region compared with haddock from the Ling Bank/Egersund Bank region. Saithe, on the other hand demonstrated higher levels of 2- and 3-ring compounds at the Ling Bank/Egersund Bank compared with fish sampled at Tampen. Overall, the highest levels of PAH metabolites in bile were measured in haddock. DNA adducts were analyzed in liver of cod, haddock and saithe at Tampen and from Ling Bank/Egersund Bank (reference site). In both areas the highest levels of DNA adducts were measured in haddock. The percentage of individuals with detectable adducts was also higher in haddock than for the other species. Haddock from Tampen had significant higher DNA adduct levels compared with haddock from Egersund Bank/Ling Bank (Mann-Whitney test), indicative of more PAH exposure in this region. Higher levels of DNA adducts in haddock caught at Tampen compared with the Egersund Bank have earlier been reported by Klungsøyr et al. (2003). Significant differences were not found for cod and saithe collected from the same areas. Analyses of alkylphenols in cod liver, haddock liver and herring muscle from Ling Bank/Egersund Bank and Tampen regions demonstrated levels below limits of detection (LOD) for all stations. The absence of alkylphenols in fish is in line with the results from the 2002 monitoring (Klungsøyr et al., 2003), and it supports the risk assessment carried out by Myhre et al. (2004) that stated that the risk for estrogenic and reproductive effects in fish after alkylphenols exposure from produced water discharges is very low. There were no differences in VTG concentration in plasma of cod caught at Tampen compared with Ling Bank/Egersund Bank that could not be explained by differences in size and sexual maturation

Widespread episodic thiamine deficiency in Northern Hemisphere wildlife

Many wildlife populations are declining at rates higher than can be explained by known threats to biodiversity. Recently, thiamine (vitamin B-1) deficiency has emerged as a possible contributing cause. Here, thiamine status was systematically investigated in three animal classes: bivalves, ray-finned fishes, and birds. Thiamine diphosphate is required as a cofactor in at least five life-sustaining enzymes that are required for basic cellular metabolism. Analysis of different phosphorylated forms of thiamine, as well as of activities and amount of holoenzyme and apoenzyme forms of thiaminedependent enzymes, revealed episodically occurring thiamine deficiency in all three animal classes. These biochemical effects were also linked to secondary effects on growth, condition, liver size, blood chemistry and composition, histopathology, swimming behaviour and endurance, parasite infestation, and reproduction. It is unlikely that the thiamine deficiency is caused by impaired phosphorylation within the cells. Rather, the results point towards insufficient amounts of thiamine in the food. By investigating a large geographic area, by extending the focus from lethal to sublethal thiamine deficiency, and by linking biochemical alterations to secondary effects, we demonstrate that the problem of thiamine deficiency is considerably more widespread and severe than previously reported

Thiamine deficiency and seabirds in Norway. A pilot study

Moe, B., Hanssen, S. A., Ytrehus, B., Balk, L., Chastel, O., Christensen-Dalsgaard, S., Gustavsson, H. & Langset, M. 2020.Thiamine deficiency and seabirds in Norway. A pilot study. NINA Report 1720. Norwegian Institute for Nature Research. Thiamine (vitamin B1) is vital for life-sustaining enzymes in cells. Previous studies have reported episodes of thiamine deficiency in marine ecosystems, and suggested that this have contributed to population declines of seabirds breeding in the Baltic Sea and elsewhere. Many Norwegian seabird populations have shown a strong decline in population size, but thiamine status has never been assessed. The objective of this pilot study was, thus, to document thiamin levels in selected species and their associated food webs, and explore methodological issues relevant for future studies or monitoring. The methodological tests showed that storage freezing temperature did not affect thiamine levels in egg yolk samples, and that thiamine levels in eggs could not be corrected for incubation time. Furthermore, the quantified thiamine levels differed between two laboratories, and we developed a predictive equation to convert thiamine levels in egg yolk samples between the laboratories. This pilot study has, for the first time, investigated thiamine levels in seabird eggs from selected species and populations in Norway mainland and Svalbard, and in their food webs. We revealed variation among species, populations and prey types. The lowest levels were found in eggs from common eiders and in blue mussel which is their prey. Eggs from herring gulls had also relatively low levels. The levels for common eiders and herring gulls were higher than previously reported from the Baltic Sea. Nevertheless, the levels from common eiders, herring gulls and blue mussels should be classified as thiamine deficient according to effect-ranges reported in these previous studies. The highest levels were found in eggs from kittiwakes and Atlantic puffins. The diet samples from kittiwakes and Atlantic puffins had higher thiamine levels compared to blue mussels. This is the first time thiamine levels are reported for kittiwakes and Atlantic puffins. This pilot-study cannot answer whether Norwegian seabird population sizes are affected by thiamine levels, but we cannot rule out that thiamine can be a limiting factor for some Norwegian seabird populations. This report identifies knowledge gaps and provides recommendations for future studies and monitoring. We suggest more sampling of levels to better understand variation among years, areas, species and populations, and also clinical examinations and surveys. Studies investigating potential effects on reproduction and survival is ultimately need to better understand potential effects on population dynamics.Moe, B., Hanssen, S. A., Ytrehus, B., Balk, L., Chastel, O., Christensen-Dalsgaard, S., Gustavsson, H. & Langset, M. 2020. Tiaminmangel og sjøfugl i Norge. En pilotstudie. NINA Rapport 1720. Norsk institutt for naturforskning. Timanin (vitamin B1) er vitalt for livsopprettholdende enzymer i celler. Tidligere studier har rapportert at det kan forekomme episoder med tiaminmangel i marine økosystemer, og foreslått at det har bidratt til bestandsnedgang hos sjøfugler som hekker i Østersjøen og andre steder. Mange norske sjøfuglbestander har vist kraftig tilbakegang, men tiaminstatus har ikke blitt undersøkt. Målsettingen med denne pilotstudien var derfor å dokumentere tiaminnivåer i utvalgte arter og deres næringskjede, og teste metodiske forhold relevant for framtidige studier og overvåkning. Metodetestene viste at frysetemperatur ikke påvirket tiaminnivåene i eggeplomme, og at tiaminnivåene i eggeplomme ikke kunne korrigeres for rugetid. Vi fant også at tiaminnivå ble kvantifisert ulikt av to laboratorier, og vi utviklet en ligning for å omregne tiaminnivå i eggeplomme mellom laboratoriene. Denne pilotstudien har for første gang undersøkt tiaminnivå i sjøfuglegg fra utvalgte arter og bestander på fastlandet i Norge og Svalbard, samt i deres næringskjeder. Vi fant variasjon mellom arter, bestander og næringsemner. De laveste nivåene var i ærfuglegg og blåskjell som er føde til ærfugl. Det var også relativt lave nivåer i egg fra gråmåke. Nivåene som ble funnet i ærfugl og gråmåke var høyere enn det som tidligere er rapportert fra Østersjøen. Likevel, både nivåene i egg fra ærfugl og gråmåke, samt nivåene i blåskjell, skal karakteriseres som tiaminmangel i henhold til effektnivåer funnet i tidligere studier fra Østersjøen. Egg fra krykkje og lunde hadde de høyeste tiaminnivåene i denne studien. Næringsemnene til disse hadde også høyere tiaminnivåer enn blåskjell. Dette er første gang tiaminnivåer er målt i krykkje og lunde. Denne pilotstudien kan ikke svare på om størrelsen til norske sjøfuglbestander er påvirket av tiaminnivåer, men vi kan ikke utelukke at tiamin kan være en begrensende faktor for noen norske sjøfuglbestander. Denne rapporten identifiserer kunnskapshull og gir anbefalinger for nye studier og overvåkning. Vi foreslår mer innsamling og måling av tiaminnivåer for å bedre forstå variasjon mellom år, områder, arter og bestander, og også kliniske undersøkelser og kartlegging. Studier som undersøker effekter på reproduksjon og overlevelse behøves for å bedre forstå den potensielle effekten på bestandsutvikling

DePierre: Initial characterization of drug-metabolizing systems in the liver ofthe northern pike, Esox lucius.

ABSTRACT: NADPH-cytochrom