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A multitude of recent studies have documented the detrimental effects of crude oil exposure on early life stages of fish, including larvae and embryos. While polycyclic aromatic hydrocarbons (PAHs), particularly alkyl PAHs, are often considered the main cause of observed toxic effects, other crude oil derived organic compounds are usually overlooked. In the current study, comprehensive two-dimensional gas chromatography coupled to mass spectrometry was applied to investigate the body burden of a wide range of petrogenic compounds in Atlantic haddock (Melanogrammus aeglefinus) and cod (Gadus morhua) embryos that had been exposed to sublethal doses of dispersed crude oil. Several groups of alkylated monoaromatic compounds (e.g. alkyl tetralins, indanes and alkyl benzenes), as well as highly alkylated PAHs, were found to accumulate in the fish embryos upon crude oil exposure. To investigate the toxicity of the monoaromatic compounds, two models (1-isopropyl-4-methyltetralin and 1-isopropyl-4-methylindane) were synthesized and shown to bioaccumulate and cause delayed hatching in developing embryos. Minor developmental effects, including craniofacial and jaw deformations and pericardial edemas, were also observed at the highest studied concentrations of the alkylindane. Image 1 • Monoaromatic compounds were found to accumulate in crude oil exposed haddock and cod embryos. • Two model compounds were synthesized and bioconcentration and toxicity tested using passive dosing. • Monoaromatic compounds displayed sublethal toxicity towards haddock embryos. Crude oil derived monoaromatic hydrocarbons accumulate in fish early life stages and may contribute to overall toxicity. [ABSTRACT FROM AUTHOR]

Atlantic haddock (Melanogrammus aeglefinus) embryos bind dispersed crude oil droplets to the eggshell and are consequently highly susceptible to toxicity from spilled oil. We established thresholds for developmental toxicity and identified any potential long-term or latent adverse effects that could impair the growth and survival of individuals. Embryos were exposed to oil for eight days (10, 80 and 300 μg oil/L, equivalent to 0.1, 0.8 and 3.0 μg TPAH/L). Acute and delayed mortality were observed at embryonic, larval, and juvenile stages with IC 50 = 2.2, 0.39, and 0.27 μg TPAH/L, respectively. Exposure to 0.1 μg TPAH/L had no negative effect on growth or survival. However, yolk sac larvae showed significant reduction in the outgrowth (ballooning) of the cardiac ventricle in the absence of other extracardiac morphological defects. Due to this propensity for latent sublethal developmental toxicity, we recommend an effect threshold of 0.1 μg TPAH/L for risk assessment models. [Display omitted] • Haddock embryos exposed to medium concentrations of oil had reduced survival. • The lowest exposure concentration impacted heart development, but not survival. • The adverse effect threshold in risk assessment should be set to 0.1 μg TPAH/L. [ABSTRACT FROM AUTHOR]

Highlights: [•] New technology creates opportunity for real time environmental monitoring. [•] Multi-sensor systems enhance understanding of human impacts. [•] Real time monitoring standards needs to be developed. [•] Experiments as part of operational monitoring is cost efficient when well planned. [ABSTRACT FROM AUTHOR]

Abstract: Heated debates are currently taking place on whether to open the area of Lofoten and Vesterålen in Northern Norway for petroleum production. Seismic explorations in this area have indicated promising petroleum resources. The area is known for its unique landscape and as a key spawning and nursery area for several economically important fish species. It hosts significant bird colonies and the world's largest-known deep-sea coral reef. New areas will be opened to petroleum production only if its high environmental value can be maintained. A risk analysis approach has become central to this decision, where the probability of a ‘worst-case scenario’ (a major oil spill) is assessed together with associated environmental impacts. This paper examines and characterises uncertainties associated with these risk assessments and some of the surrounding debates. Further, the paper reveals implications of these uncertainties: (1) potential values embedded in the risk assessments, (2) lack of validity of quantified worst-case scenarios and their probabilities and impacts, (3) limited prospects of filling addressed knowledge gaps and (4) how risk assessments restrict the debate on what issues and uncertainties are considered relevant. Taken together, this suggests that discussions on alternative approaches to decision making should be more prominent in public and political debates. [Copyright &y& Elsevier]

Abstract: Offshore petroleum activities are the focus of highly politicised debates globally. Typically, public debate is sparked by catastrophic events, such as the 2010 oil spill in the Gulf of Mexico, and decision-making processes fuelled by the assessment of ‘worst-case scenarios’. However, everyday ‘routine’ petroleum operations also impact the marine ecosystems and adjoining socio-economic sectors, but the extent and severity of the impacts are uncertain. This paper takes as its point of departure routine operations and their surrounding uncertainties. Particularly, it focuses on the debates of whether to extend routine petroleum operations in vulnerable and valuable parts of Norway, such as the Lofoten area and the Sula Ridge. These conflicts draw on important and for some, epistemological uncertainties that surround the impacts of routine operations. The paper argues that it is necessary to first highlight these uncertainties, rather than marginalise them, and second, recognise that uncertainties are not simply a scientific challenge, but can be a powerful political tool. This paper unpacks and explores uncertainties associated with three phases of routine operations, that are used to steer political actions: (i) the impacts of seismic surveys on fish and marine mammals; (ii) the impacts of drilling mud and drill cuttings on benthic communities such as deep-sea coral reefs; and (iii) the impacts of produced water on the marine environment. The paper discusses the importance of transparency in addressing these uncertainties, and emphasises the need to implement the precautionary principle in a more participatory way. It thus proposes participatory exercises in order to allow the recognition of the epistemological nature of uncertainties. [Copyright &y& Elsevier]

Abstract: Biological markers of produced water (PW) exposure were studied in Atlantic cod (Gadus morhua) in both laboratory and field experiments, using authentic PW from a North Sea oil field. In the laboratory study, the PW exposure yielded significantly elevated levels of metabolites of polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APs) in bile even at the lowest exposure dose (0.125% PW). Other biomarkers (hepatic CYP1A induction and DNA adduct formation) responded at 0.25% and 0.5% PW concentrations. In the field study, bile metabolite markers and hepatic CYP1A were clearly increased in fish caged close to the PW outfall. Induction of plasma vitellogenin was not found in laboratory or field exposures, suggesting that the levels of oestrogen agonists (such as APs) might not have been sufficient to elicit induction, under the present conditions. The applicability of the biomarkers for use in water column biomonitoring programs is discussed. [Copyright &y& Elsevier]

Abstract: Proteomics is a new and promising approach to evaluate potential effects of pollution. In order to investigate if there is a direct link between the protein expression profiles obtained by the SELDI–TOF MS technology and effects observed at the organism level in fish, plasma samples from unexposed and 20ppb alkylphenol exposed female Atlantic cod (Gadus morhua) with high phenotypic variation in gonadosomatic index (GSI) were analyzed by SELDI–TOF MS. Principle component analysis (PCA) showed that the major proteomic variation present in the dataset (i.e. 23.6%) could be significantly correlated to the individual variation in GSI, which indicates that SELDI–TOF MS data can reflect effects observed at higher levels of organization in fish. Further exploration of the other principal components revealed an additional proteomic pattern specific for the alkylphenol exposed females. Hence, this study supports the usefulness of SELDI–TOF MS as a proteomic tool in ecotoxicological research. [Copyright &y& Elsevier]

Abstract: The aim of the work was to establish methodology for realistic laboratory-based test exposures of organisms to oil dispersions, specifically designed to generate parameterized toxicity data. Such data are needed to improve the value of numerical models used to predict fate and effects of oil spills and different oil spill responses. A method for continuous and predictable in-line production of oil dispersions with defined size distribution of different oil qualities was successfully established. The system enables simultaneous comparison between the effects of different concentrations of dispersion and their corresponding equilibrium water soluble fractions. Thus, net effects of the oil droplet fraction may be estimated. The method provides data for comparing the toxicity of oil dispersions generated both mechanically and with the use of chemical dispersions, incorporating the toxicity of both dissolved oil and droplets of oil. [Copyright &y& Elsevier]

Abstract: Produced water (PW), a by-product of the oil-production process, contains large amount of alkylphenols (APs) and other harmful oil compounds. In the last 20 years, there have been increasing concerns regarding the environmental impact of large increases in the amounts of PW released into the North Sea. We have previously shown that low levels of APs can induce disruption of the endocrine and reproductive systems of Atlantic cod (Gadus morhua). The aims of this follow-up study were to: (i) identify the lowest observable effect concentration of APs; (ii) study the effects of exposure to real PW, obtained from a North Sea oil-production platform; and (iii) study the biological mechanism of endocrine disruption in female cod. Fish were fed with feed paste containing several concentrations of four different APs (4-tert-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol and 4-n-heptylphenol) or real PW for 20 weeks throughout the normal period of vitellogenesis in Atlantic cod from October to January. Male and female cod, exposed to AP and PW, were compared to unexposed fish and to fish fed paste containing 17β-oestradiol (E2). Approximately 60% of the females and 96% of the males in the unexposed groups were mature at the end of the experiment. Our results show that exposure to APs and E2 have different effects depending on the developmental stage of the fish. We observed that juvenile females are advanced into puberty and maturation, while gonad development was delayed in both maturing females and males. The AP-exposed groups contained increased numbers of mature females, and significant differences between the untreated group and the AP-treated groups were seen down to a dose of 4μg AP/kg body weight. In the high-dose AP and the E2 exposed groups, all females matured and no juveniles were seen. These results suggest that AP-exposure can affect the timing of the onset of puberty in fish even at extremely low concentrations. Importantly, similar effects were not seen in the fish that were exposed to real PW. [Copyright &y& Elsevier]

Abstract: Polycyclic aromatic hydrocarbons (PAH) and alkylphenols (AP) that are present in routine discharges of produced water (PW) from the offshore industry continue to cause concern. The suitability of biological methods and chemical based passive samplers to determine exposure to these compounds was tested by deploying them around an oil installation and at reference locations in the North Sea. PAH and AP were analysed either as parent compounds in passive samplers and mussel tissue or as metabolites in fish bile. Generally the pattern of exposure relative to proximity to the discharge was represented by mussels, SPMDs and fish for PAH. Fish and SPMDs showed good correlation for PAH accumulations, whereas some differences were apparent between mussels and SPMDs. POCIS was the only technique tested that could accurately measure the most abundant AP in PW. The advantages of biologically independent measures of exposure for inclusion in discharge monitoring studies are outlined. [Copyright &y& Elsevier]

Abstract: Produced water (PW) contains numerous toxic compounds of natural origin, such as dispersed oil, metals, alkylphenols (APs), and polycyclic aromatic hydrocarbons (PAHs). In addition, PW also contains many different chemicals which have been added during the oil production process. In the study described here, cod were exposed to real PW collected from an oil production platform in the North Sea. This was done in order to best recreate the most realistic field-exposure regime in which fish will be affected by a wide range of chemicals. The biological effects found in this study therefore cannot be assigned to one group of chemicals alone, but are the result of exposure to the complex chemical mixture found in real PW. Since APs are well known to cause endocrine disruption in marine organisms, we focused our chemical analysis on APs in an attempt to better understand the long-term effects of APs from PW on the biology of fish. In this study, cod were exposed to several concentrations of real PW and 17β-oestradiol (E2), a natural oestrogen, at different developmental stages. Cod were exposed to PW either during the embryo and early larvae stage (up to 3 months of age) or during the early juvenile stage (from 3 to 6 months of age). Results showed that, in general, APs bioconcentrate in fish tissue in a dose and developmental stage dependent manner during PW exposure. However, juveniles appeared able to effectively metabolise the short chain APs. Importantly, PW exposure had no effect on embryo survival or hatching success. However, 1% PW clearly interfered with the development of normal larval pigmentation. After hatching most of the larvae exposed to 1% PW failed to begin feeding and died of starvation. This inability to feed may be linked to the increased incidence of jaw deformities seen in these larvae. In addition, cod exposed to 1% PW, had significantly higher levels of the biomarkers vitellogenin and CYP1A in plasma and liver, respectively. No similar effects were seen in cod exposed to either 0.1% or 0.01% PW. [Copyright &y& Elsevier]

Abstract: In order to assess the environmental impact of aquatic discharges from the offshore oil industry, polar organic chemical integrative samplers (POCIS) and semipermeable membrane devices (SPMDs) were deployed around an oil platform and at reference locations in the North Sea. Exposure to polycyclic aromatic hydrocarbons (PAH) and alkylated phenols (AP) was determined from passive sampler accumulations using an empirical uptake model, the dissipation of performance reference compounds and adjusted laboratory derived sampling rates. Exposure was relatively similar within 1–2km of the discharge point, with levels dominated by short chained C1–C3 AP isomers (19–51ngL−1) and alkylated naphthalenes, phenanthrenes and dibenzothiophenes (NPD, 29–45ngL−1). Exposure stations showed significant differences to reference sites for NPD, but not always for more hydrophobic PAH. These concentrations are several orders of magnitude lower than those reported to give both acute and sub-lethal effects, although their long term consequences are unknown. [Copyright &y& Elsevier]

Abstract: A biotest system for environmentally realistic exposure of fish to produced water (PW) was developed and tested. Authentic PW was collected at an oil production platform in the North Sea and preserved by freezing in multiple aliquots a 25L. After transport to the test laboratory onshore, daily PW aliquots were thawed, homogenised and administered to the test fish, Atlantic cod (Gadus morhua), in two diluted exposure concentrations, 0.1% and 0.5%, during a 15 d period, using a continuous flow-through exposure setup. Positive control groups were exposed to two crude oil treatments for comparison. Chemical analyses showed that alkylphenol (AP) and PAH concentrations in PW exposure waters were very low. Observations of significantly increased AP and PAH metabolite levels in PW exposed fish demonstrated the suitability of the biotest system for its use in biological exposure/effect studies of PW, and it also demonstrated the sensitivity of bile metabolites as PW exposure markers in fish. The relevance of the biotest system for PW effect studies and for validating modelled environmental risk estimates of PW dischargers from offshore oil production is discussed. [Copyright &y& Elsevier]

Abstract: The release of produced water (PW), a by-product of offshore oil production, has increased in Norwegian waters in recent years. Alkylphenols (AP), a major component of PW, have been shown to have endocrine disrupting effects on several fish species. In the present study, four groups of female Atlantic cod (Gadus morhua) were orally exposed for 20 weeks to two different concentrations of a mixture of C4–C7 APs, PW or 17β-estradiol. The transcriptional responses in the liver of Atlantic female cod were studied using a custom-made cDNA microarray. The largest transcriptional effects were seen in cod exposed to the lowest dose of APs. Several biological processes such as glycolysis, apoptosis and the general stress response were affected by exposure to APs. In addition, genes coding for the detoxification enzymes CYP1A and sulfotransferase 2 were up-regulated in the low exposure group. Significant reduction in gonadosomatic index (GSI) and the concentration of plasma vitellogenin were seen in both AP and 17β-estradiol exposed cod. Exposure to PW had little effect on GSI and the regulation of stress responsive genes. The findings indicate that chronic exposure to low levels of APs may cause a stress response and delayed maturation in female cod. [Copyright &y& Elsevier]

Abstract: Offshore oil production releases large amounts of lipophilic compounds in produced water into the ocean. In 2004, 143 million m3 produced water, containing approximately 13 tons of long-chain (>C4) alkylphenols (AP), was discharged from installations in the Norwegian sector of the North Sea. Long-chain APs are known to cause endocrine disruption in a number of species. However, relatively little is known about their long-term effects in the marine environment. In the present study, Atlantic cod (Gadus morhua) were exposed (0.02 to 80 mg AP/kg) to a mixture (1:1:1:1) of APs (4-tert-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol and 4-n-heptylphenol) or 17 β-estradiol (5 mg E2/kg) for 5 weeks and the effect on the fatty acid profile and cholesterol content in the membrane lipids from the liver and the brain was studied. We also determined the interaction between different para-substituted APs and glycerophospholipids (native phospholipids extracted from cod liver and brain) and model phosphatidylcholine (PC 16:0/22:6 n-3) in monolayers with the Langmuir–Blodget technique. The study demonstrated that APs and E2 alter the fatty acid profile in the polar lipids (PL) from the liver to contain more saturated fatty acids (SFA) and less n-3 polyunsaturated fatty acids (n-3 PUFA) compared with control. In the brain of the exposed groups a similar effect was demonstrated, although with higher saturation of the fatty acids found in the neutral lipids (mainly cholesterol ester), but not in the polar lipids. The AP and E2 exposure also gave a decline in the cholesterol levels in the brain. The in vitro studies showed that APs increased the mean molecular areas of the PLs in the monolayers at concentrations down to 5 μM, most likely due to intercalation of the APs between PL molecules. The increase in molecular area increased with the length of the alkyl side chain. [Copyright &y& Elsevier]

Abstract: Produced water, a by-product of offshore oil production, contains significant amounts of alkylphenols (APs). Many studies have shown that APs cause endocrine disruption in marine organisms, but relatively little is currently known about their long-term effects on the biology of pelagic fish. Here, we describe in detail the effects of APs on the reproductive potential of first-time spawning Atlantic cod (Gadus morhua). Cod were fed with feed paste containing four APs (4-tert-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol and 4-n-heptylphenol), at a range of concentrations, for either 1 or 5 weeks. AP-exposed fish were compared to unexposed fish and to fish fed paste containing natural estrogen (17β-estradiol). Our results showed that in female fish AP exposure impaired oocyte development, reduced estrogen levels, and delayed the estimated time of spawning by 17–28 days. Similarly, in male fish, we observed that AP-exposure reduced 11-keto-testosterone concentrations, and caused a small induction of VTG levels. We also observed impaired testicular development, with an increase in the amount of spermatogonia and a reduction in the amount of spermatozoa present. Taken together these results suggest that APs released into the sea via produced water may have a negative influence on the overall reproductive fitness of cod populations. [Copyright &y& Elsevier]

Offshore oil production releases large amounts of lipophilic compounds in produced water and into the ocean. The discharge of produced water from the Norwegian petroleum sector has increased from 26 million m3 in 1993 to 120 million m3 in 2001, and it continues to increase. Produced water contains significant amounts of alkylphenols, which have been reported to be estrogenic, causing endocrine disruption in fish. In year 2000, approximately 44 tons of alkylphenols were released on the Norwegian continental shelf in connection with discharge of produced water. Except from being estrogenic, relatively little is known about the effects of alkylphenols when released in the marine environment. Our objective was to study how alkylphenols affect the redox status in first spawning Atlantic cod (Gadus morhua) of both sexes. Model compounds tested included 4-tert-butylphenol (C4), 4-n-pentylphenol (C5), 4-n-hexylphenol (C6) and 4-n-heptylphenol (C7), all found in produced water. First spawning Atlantic cod were force-fed a mixture of these four alkylphenols, ranging between 0.02 and 80 ppm or 5 ppm 17β-estradiol (E2), for 1 or 4 weeks. Increased hepatic total glutathione concentration in response to alkylphenol exposure was detected in female fish compared to control group after 1-week exposure, an effect not seen after 4 weeks. Furthermore, hepatic total glutathione concentration was sex dependent, where male fish sampled after 4 weeks had higher levels of glutathione than female fish. Increased glutathione reductase catalytic activities in both male and female fish were seen after exposure to 0.02 ppm alkylphenol mixture in 4 weeks. The glutathione S-transferase activity was only affected in male fish exposed to 0.02 ppm alkylphenols, and glucose-6-phosphate dehydrogenase activity increased in female fish exposed to 0.02 ppm alkylphenol mixture for 1 week. The increase of hepatic total glutathione content as well as the effects on glutathione reductase activities suggests that alkylphenol exposure affects the redox status in Atlantic cod. [Copyright &y& Elsevier]

Alkylphenols are continuously released into the ocean as a result of offshore oil production. Alkylphenols, including 4-tert-butylphenol (C4), 4n-pentylphenol (C5), 4n-hexylphenol (C6), and 4n-heptylphenol (C7), up to 237 ppb concentrations, have been detected in produced water from oil platforms. Previous studies have shown that alkylphenols induce vitellogenesis in fish. Atlantic cod (Gadus morhua) of both sexes were force-fed with various doses ranging between 0.02 and 80 ppm of a mixture of alkylphenols (C4:C5:C6:C7 ratio 1:1:1:1) or 5 ppm 17β-estradiol. We investigated effects on hepatic CYP1A and CYP3A protein expression in protein blots, using antibodies against scup (Stenotomus chrysops) CYP1A1 and rainbow trout (Oncorhynchus mykiss) CYP3A. There was a sexually dimorphic expression of CYP1A and CYP3A protein levels, with females expressing higher levels than males. Treatment of male Atlantic cod with 17β-estradiol resulted in increased CYP1A and CYP3A protein levels. Exposure to alkylphenols resulted in a dose-dependent increase of CYP1A and CYP3A protein expression in males, but not in females. However, this increase of CYP1A protein levels was not reflected on the CYP1A-mediated ethoxyresorufin-O-deethylase (EROD) activity, implying that alkylphenols inhibited the CYP1A enzyme activity in vivo. In vitro inhibition studies with pooled liver microsomes from Atlantic cod confirmed that the alkylphenols mixture efficiently inhibited the CYP1A activity (IC50=10 μM), although the inhibitory effect of each individual alkylphenol varied. The IC50 values for each individual alkylphenol on the CYP1A activity were, in a descending order of magnitude: [C7>C6>C5≫C4], ranging from 12 to 300 μM with decreased length of the 4-alkyl chain. The effect of alkylphenols on the CYP3A activity in vitro in liver microsomes also was investigated, using the fluorescent 7-benzyloxy-4-[trifluoromethyl]-coumarin (BFC) as a diagnostic CYP3A substrate. The alkylphenol mixture inhibited CYP3A activity with IC50 value at 100 μM. The IC50 values for each individual alkylphenol on CYP3A activity were, in a descending order of magnitude: [C5>C6>C7>C4], ranging between 60 and 250 μM. Taken together, our results show that the alkylphenol mixture and 17β-estradiol resulted in elevated hepatic CYP1A and CYP3A expression in male Atlantic cod. The alkylphenol mixture strongly inhibited CYP1A activities, whereas it weakly inhibited CYP3A activity in Atlantic cod liver microsomes in vitro. In addition, 17β-estradiol was a weak inhibitor of CYP3A activity (IC50=75 μM) and did not notably inhibit the CYP1A activity in vitro. [Copyright &y& Elsevier]

[Display omitted] • Fatty acid profile in W. bursa is significantly affected by fish farming; • W. bursa's microbiome differs under impacted and non-impacted sites; • W. bursa appears more resilient to organic enrichment than previously thought. Sustained growth of world-wide sea farming and the search of optimal growing conditions have driven several countries, including Norway, to establish new finfish sites in more exposed, high current locations. Characterized by a range of gravel, broken rock and/or bedrock, these complex environments and the associated diverse range of epifauna species are not easily monitored via traditional methodologies (e.g. morpho-taxonomic identification and enumeration, and compound analyses of sediment grabs). Consequently, little is known about many of the benthic inhabitants, or how they may respond to fish farming. In this study, we aimed to initiate addressing this knowledge gap by assessing the response of the sponge Weberella bursa (Polymastidea) to salmon aquaculture. Fourteen specimens were translocated along a distance gradient from a salmon farm located along the mid-west coast of Norway. Following 7 months of exposure, their epithelial tissue were analysed for gene expression analysis (mRNA), fatty acid (FA), stable isotope and taxonomic and functional microbiome characterization. Among all datasets, only fatty acid profiles showed significant changes associated with fish farm activities, with higher proportion of terrestrial FAs and long saturated and monounsaturated FAs near the farm. These results suggest that W. bursa sponges may be more resistant to organic enrichment than previously thought. Nonetheless, several putative indicators of non-lethal response could be identified. Specifically, W. bursa specimens located underneath the farm tended to have reduced ribosomal activity while having increased expression of genes controlling cell apoptosis (e.g. caspase-3, cytochrome c oxidase and death domain proteins). Based on predictive functional analysis, specimens near to the farm were also found to be particularly enriched in sulfur and nitrogen cycling bacteria, and in microbial taxa with anti-toxin and xenobiotic biodegradation capability, notably of benzyl benzoate compounds used in sea lice treatments. These results indicate that potentially harmful elements such as sulfite, nitrite and pesticides may be neutralized and degraded by a particularly enriched set of bacteria in W. bursa microbiome. While additional research is needed to validate these putative indicators, our study provides a first glimpse as to how sessile organisms may respond and adapt to environmental changes induced by fin fish farming, and pave the way to the development of novel monitoring tools adapted to mix and hard bottom habitats. [ABSTRACT FROM AUTHOR]

[Display omitted] • Authentication of mixed samples using proteomics Spectral library matching approach. • Estimating abundance of fish species in commercial seafood samples. • Spectra library approach successfully identifies fish in commercial products. • Other compounds and treatments do not affect results on commercial products. • Spectra library matching approach can be employed to combat food fraud. Seafood fraud has become a global issue, threatening food security and safety. Adulteration, substitution, dilution, and incorrect labeling of seafood products are fraudulent practices that violate consumer safety. In this context, developing sensitive, robust, and high-throughput molecular tools for food and feed authentication is becoming crucial for regulatory purposes. Analytical approaches such as proteomics mass spectrometry have shown promise in detecting incorrectly labeled products. For the application of these tools, genome information is crucial, but currently, for many marine species of commercial importance, such information is unavailable. However, when combining proteomic analysis with spectral library matching, commercially important fish species were successfully identified, differentiated, and quantified in pure muscle samples and mixtures, even when genome information was scarce. This study further tested the previously developed spectral library matching approach to differentiate between 29 fish species from the North Sea and examined samples including individual fish, laboratory-prepared mixtures and commercial products. For authenticating libraries generated from 29 fish species, fresh muscle samples from the fish samples were matched against the reference spectral libraries. Species of the fresh fish samples were correctly authenticated using the spectral library approach. The same result was obtained when evaluating the laboratory-prepared mixtures. Furthermore, processed commercial products containing mixtures of two or three fish species were matched against these reference spectral libraries to test the accuracy and robustness of this method for authentication of fish species. The results indicated that the method is suitable for the authentication of fish species from highly processed samples such as fish cakes and burgers. The study shows that current and future challenges in food and feed authentication can efficiently be tackled by reference spectral libraries method when prospecting new resources in the Arctic. [ABSTRACT FROM AUTHOR]

Abstract: In this study Atlantic cod (Gadus morhua) were exposed to different levels of North Sea produced water (PW) and 17β-oestradiol (E2), a natural oestrogen, from egg to fry stage (90 days). By comparing changes in protein expression following E2 exposure to changes induced by PW treatment, we were able to compare the induced changes by PW to the mode of action of oestrogens. Changes in the proteome in response to exposure in whole cod fry (approximately 80 days post-hatching, dph) were detected by two-dimensional gel electrophoresis and image analysis and identified by MALDI-ToF-ToF mass spectrometry, using a newly developed cod EST database and the NCBI database. Many of the protein changes occurred at low levels (0.01% and 0.1% PW) of exposure, indicating putative biological responses at lower levels than previously detected. Using discriminant analysis, we identified a set of protein changes that may be useful as biomarker candidates of produced water (PW) and oestradiol exposure in Atlantic cod fry. The biomarker candidates discovered in this study may, following validation, prove effective as diagnostic tools in monitoring exposure and effects of discharges from the petroleum industry offshore, aiding future environmental risk analysis and risk management. [Copyright &y& Elsevier]

Abstract: Produced water released into the sea from oil installations contains a vast number of organic compounds. This work focuses on the analysis and identification of phenols in produced water, in particular long-chain para-substituted alkylphenols, which act as endocrine disruptors for marine biota. Some alkylphenol standards, unavailable commercially, have been synthesised and some compounds of interest identified. However, a complete identification is not possible since conventional GC techniques cannot achieve the desired degree of separation. An overview of the levels of the 52 known alkylphenols in produced water from nine oil installations in the North and Norwegian Seas has been made. The previously unidentified alkylphenols in produced water have been characterised by means of alkylphenol retention indices (APRI) and mass spectrometry, and their total amounts estimated for the same nine locations. Our results confirm the presence of naphthols and other as yet unidentified compounds in produced water, while thiophenols were not detected by the used technique. [Copyright &y& Elsevier]

Regular discharges of produced water from the oil and gas industry represents the largest direct discharge of effluent into the marine environment worldwide. Organic compound classes typically reported in produced water include saturated hydrocarbons, monoaromatic and polyaromatic hydrocarbons (MAHs, PAHs) as well as oxygenated compounds, such as phenols, acids and ketones. This forms a cocktail of known and suspect toxicants, but limited knowledge is yet available on the sub-lethal toxicity of produced water to cold-water marine fish species. In the present work, we conducted a 4-day exposure of embryos of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) to produced water extracts equivalent to 1:50, 1:500 and 1:5000 times dilutions of raw effluent. No significant reduction in survival or hatching success was observed, however, for cod, hatching was initiated earlier for exposed embryos in a concentration-dependent manner. During recovery, significantly reduced embryonic heart rate was observed for both species. After hatch, larvae subjected to embryonic exposure to produced water extracts were smaller, and displayed signs of cardiotoxicity, jaw and craniofacial deformations. In order to improve risk assessment and regulation of produced water discharges, it is important to identify which produced water components contribute to these effects. • Atlantic cod and haddock embryos were exposed to produced water extracts mimicking 50–5000 times dilution of produced water. • Exposure to produced water caused no significant effects on acute mortality and hatching success. • Delayed effects were observed in larvae displaying symptoms of cardiotoxicity and developmental deformations. [ABSTRACT FROM AUTHOR]

Crude oil accidentally spilled into the marine environment undergoes natural weathering processes that result in oil components being dissolved into the water column or present in particulate form as dispersed oil droplets. Oil components dissolved in seawater are typically considered as more bioavailable to pelagic marine organisms and the main driver of crude oil toxicity, however, recent studies indicate that oil droplets may also contribute. The adhesion of crude oil droplets onto the eggs of pelagic fish species may cause enhanced transfer of oil components via the egg surface causing toxicity during the sensitive embryonic developmental stage. In the current study, we utilized an oil droplet dispersion generator to generate defined oil droplets sizes/concentrations and exposed Atlantic cod ( Gadus morhua ) and haddock ( Melanogrammus aeglefinus ) to investigate if the potential for dispersed oil droplets to adhere onto the surface of eggs was species-dependent. The influence of a commercial chemical dispersant on the adhesion process was also studied. A key finding was that the adhesion of oil droplets was significantly higher for haddock than cod, highlighting key differences and exposure risks between the two species. Scanning electron microscopy indicates that the differences in oil droplet adhesion may be driven by the surface morphology of the eggs. Another important finding was that the adhesion capacity of oil droplets to fish eggs is significantly reduced (cod 37.3%, haddock 41.7%) in the presence of the chemical dispersant. [ABSTRACT FROM AUTHOR]

DNA adducts in fish represent a very important genotoxicity endpoint in environmental monitoring, being a pre-mutagenic lesion that plays an essential role in the initiation of carcinogenesis. The analysis of DNA adducts is a challenging task due to the low concentration of the analyte. Methods are available to determine the presence of DNA adducts, although further knowledge is required to fully understand the nature of the adducts and responsible xenobiotics (i.e. position of adduct in DNA, most active xenobiotic and metabolite forms, structural information). At present, 32 P-postlabeling is the most used method that has the required sensitivity for DNA adduct analyses in both human health and environmental monitoring. Development of new mass spectrometry based methods for identifying DNA adducts in complex matrixes is now considered as a necessary mission in toxicology in order to gain the necessary information regarding adduct formation and facilitate tracking sources of contamination. Mass spectrometry therefore represents the future of DNA adduct detection, bringing along a series of challenges that the scientific community is facing at present. [ABSTRACT FROM AUTHOR]

Alive eggs of marine species with pelagic eggs float, while dead eggs usually sink. A non-invasive method for counting the number of floating eggs therefore gives the possibility to track survival throughout experiments. In this paper we present an automatic image analysis method for counting live pelagic eggs of marine fish. Pelagic fish eggs are typically transparent and difficult to detect in images. Current image analysis methods for counting pelagic fish eggs are therefore done on eggs transfixed in a polymer to create contrast between the eggs and the background. This kills the eggs. The main advantage of the presented method is that it is non-invasive and only requires a minimum of handling of the eggs. As case studies we collected images of Atlantic haddock ( Melanogrammus aeglefinus ) and Atlantic cod ( Gadus morhua ) eggs. The eggs in the images were manually counted for verification of the methodology. The average counting error of false positives was 6% and the average counting error of false negatives was 2%. This demonstrates that the method is objective and accurate. [ABSTRACT FROM AUTHOR]

Highlights: [•] We investigate endocrine disrupting effects of commercial naphthenic acids in fish. [•] Androgenised female stickleback screen was applied. [•] A variant of the OECD 21-d fish screen was applied. [•] Commercial NAs might enhance the androgenic potential of DHT. [ABSTRACT FROM AUTHOR]

Highlights: [•] H295r cells were exposed to polar hydrocarbons. [•] Alkylphenols, naphthenic acids and produced water induced E2 and P4 production. [•] Exposure to naphthenic acids caused a decrease in testosterone. [•] All compounds cause an up-regulation in CYP1A. [Copyright &y& Elsevier]

Abstract: Fish in the North Sea are exposed to relatively high levels of halogenated compounds in addition to the pollutants released by oil production activities. In this study male Atlantic cod (Gadus morhua) were orally exposed to environmental realistic levels (low and high) of weathered crude oil and/or a mixture of POPs for 4weeks. Lipid composition in brain and in liver extracts were analysed in order to assess the effects of the various pollutants on membrane lipid composition and fatty acid profiles. Transcriptional effects in the liver were studied by microarray and quantitative real-time RT-PCR. Chemical analyses confirmed uptake of polychlorinated biphenyls (PCBs) and chlorinated pesticides, polybrominated diphenyl ethers (PBDEs) and perfluorooctanesulfonate (PFOS) in the liver and excretion of metabolites of polyaromatic hydrocarbons (PAHs) in the bile. Treatment with POPs and/or crude oil did not induce significant changes in lipid composition in cod liver. Only a few minor changes were observed in the fatty acid profile of the brain and the lipid classes in the liver. The hypothesis that pollution from oil or POPs at environmental realistic levels alters the lipid composition in marine fish was therefore not confirmed in this study. However, the transcriptional data suggest that the fish were affected by the treatment at the mRNA level. This study suggests that a combination of oil and POPs induce the CYP1a detoxification system and gives an increase in the metabolism and clearing rate of PAHs and POPs, but with no effects on membrane lipids in male Atlantic cod. [Copyright &y& Elsevier]

Abstract: Concern has been raised over whether environmental release of alkylphenols (AP) in produced water (PW) discharges from the offshore oil industry could impose a risk to the reproduction of fish stocks in the North Sea. An environmental risk assessment (ERA) was performed to determine if environmental exposure to PW APs in North Sea fish populations is likely to be high enough to give effects on reproduction endpoints. The DREAM (Dose related Risk and Effect Assessment Model) software was used in the study and the inputs to the ERA model included PW discharge data, fate information of PW plumes, fish distribution information, as well as uptake and elimination information of PW APs. Toxicodynamic data from effect studies with Atlantic cod (Gadus morhua) exposed to APs were used to establish a conservative environmental risk threshold value for AP concentration in seawater. By using the DREAM software to 1) identify the areas of highest potential risk and 2) integrate fish movement and uptake/elimination rates of APs for the chosen areas we found that the environmental exposure of fish to APs from PW is most likely too low to affect reproduction in wild populations of fish in the North Sea. The implications related to risk management of offshore PW and uncertainties in the risk assessment performed are discussed. [Copyright &y& Elsevier]

Early life stages of fish are highly sensitive to crude oil exposure and thus, short term exposures during critical developmental periods could have detrimental consequences for juvenile survival. Here we administered crude oil to Atlantic haddock (Melanogrammus aeglefinus) in short term (3-day) exposures at two developmental time periods: before first heartbeat, from gastrulation to cardiac cone stage (early), and from first heartbeat to one day before hatching (late). A frequent sampling regime enabled us to determine immediate PAH uptake, metabolite formation and gene expression changes. In general, the embryotoxic consequences of an oil exposure were more severe in the early exposure animals. Oil droplets on the eggshell resulted in severe cardiac and craniofacial abnormalities in the highest treatments. Gene expression changes of Cytochrome 1 a, b, c and d (cyp1a , b , c , d), Bone morphogenetic protein 10 (bmp10), ABC transporter b1 (abcb1) and Rh-associated G-protein (rhag) were linked to PAH uptake, occurrence of metabolites of phenanthrene and developmental and functional abnormalities. We detected circulation-independent, oil-induced gene expression changes and separated phenotypes linked to proliferation, growth and disruption of formation events at early and late developmental stages. Changes in bmp10 expression suggest a direct oil-induced effect on calcium homeostasis. Localized expression of rhag propose an impact on osmoregulation. Severe eye abnormalities were linked to possible inappropriate overexpression of cyp1b in the eyes. This study gives an increased knowledge about developmentally dependent effects of crude oil toxicity. Thus, our findings provide more knowledge and detail to new and several existing adverse outcome pathways of crude oil toxicity. Unlabelled Image • Toxicity to dissolved oil was compounded by oil droplet fouling on the eggshell. • Exposure early in development resulted in higher PAH uptake due to lower metabolism resulting in more severe abnormalities. • A rapid and circulation-independent regulation of bmp10 suggested a direct oil-induced effect on calcium homeostasis. • Expression of rhag indicated a direct oil-induced effect on osmoregulatory cells and osmoregulation. • Severe eye abnormalities especially in the late exposure was linked to inappropriate overexpression of cyp1b in the eyes. [ABSTRACT FROM AUTHOR]

• Even though small sample sizes and differences in age compositions made it challenging to compare the Barents Sea harp seal body condition between sampling periods, there were some indications of a possible decline over the past 25 years. • Current short-term (analyses of digestive tract contents) prey use by the seals revealed that pelagic amphipods (Themisto libellula) and polar cod (Boreogadus saida) were the most prominent prey species, as also observed for harp seals on their northern feeding grounds in the Barents Sea during autumn nearly 3 decades ago. • The long-term diet of the seals, based on stable isotope and fatty acid composition, was reflected well in the short-term stomach contents composition. • Results from acoustic and trawl surveys conducted concurrently with the seal sampling confirmed that the pelagic amphipods were by far the most abundant prey observed on the assumed harp seal feeding grounds, followed by krill (Thysanoessa sp.), Atlantic cod (Gadus morhua) and polar cod. • Prey-preference analyses revealed that the seals displayed a clear positive preference for polar cod and random feeding and negative preference for amphipods and krill, respectively, i.e. amphipods and krill were consumed in less proportions than observed in the environment. In September 2016, a marine ecosystem survey covered all trophic levels from phytoplankton to seals in the Arctic Ocean to the west and north of Svalbard. At the ice edge, 26 harp seals were sampled to assess whether recent environmental changes had affected their diets and body condition by comparing our current results with previous investigations conducted 2–3 decades ago in the northern Barents Sea, when the ice edge was located much further south. Our results suggest that the body condition was slightly but significantly lower for one year and older seals in 2016 compared with seals sampled in the early 1990s. Furthermore, we confirmed previous findings that polar cod (Boreogadus saida) and the pelagic hyperiid amphipod Themisto libellula still dominate the seal diet. One consequence of current ice edge localisation north of Svalbard is that the water depth underneath is now 500 m and deeper, which probably explains the absence of bottom associated species, and the presence of species such as Atlantic cod (Gadus morhua) and blue whiting (Micromesistius poutassou) as alternative species in addition to polar cod and T. libellula in the seal diets. Stable isotope data also suggest possible long-term importance in the seal diet of T. libellula and of low trophic level benthopelagic prey such as the squid Gonatus fabricii over mid-trophic level pelagic fishes, but with a strong component of small, benthopelagic fish such as blue whiting. The long-term importance of pelagic crustaceans was also suggested from the fatty acid analyses. Assessment of the abundance of prey showed that T. libellula was by far the most abundant prey species in the upper water layers, followed by krill (mainly Thysanoessa inermis), Atlantic cod and polar cod. Prey-preference analyses indicated that polar cod was the most preferred prey species for the seals. [ABSTRACT FROM AUTHOR]

Naphthalene is the simplest representative of polycyclic aromatic hydrocarbons (PAHs). It is detected as major pollutant in the different compartments of the environment. This compound is considered by the international agency for research on cancer (IARC), the specialized cancer agency of the World Health Organisation (WHO), as a possible carcinogenic (group 2B) since 2002, mainly based on studies on chronic inhalation in rodent by the national toxicology program of the U.S. department of health and human services. In humans, its main metabolites correspond to derivatives substituted in position and 1 and 2 as 1,2-naphthoquinone (1,2-NphQ). Based on previous studies, 1,2-NphQ is supposed to react with DNA to form mostly depurinating adducts, a possible initiating step of carcinogenicity. To confirm this potentiality, adducts were synthetized by the reaction of 1,2-NphQ with 2′-deoxyguanosine (2′-dG) in N,N -dimethylformamide (DMF), water and calf thymus DNA. 2′-dG adducts were analyzed by 32P post-labelling, HPLC with ultra-violet detection and ultra-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). We found stable DNA adducts detected in DNA. We proposed a formation mechanism by a 1,4-Michael addition with 2′-dG. Adducts with 2′-deoxyxanthosine are formed after a spontaneous deamination of 2′-dG. These adducts are good candidates as biomarkers allowing evaluation of exposure to naphthalene and its derivatives in the development of pathologies such as cancer. Image 1 • 1,2-Naphthoquinone (1,2-NphQ) forms stable adduct with 2′-dG and DNA. • The pattern of adducts formed is different between DMF, water and DNA. • Stable 1,2-NphQ-DNA adducts were identified. • Deamination of 2′-dG results in the formation of stable adduct with deoxyxanthosine. • Kinetics of formation of adducts were determined in DMF at different temperatures. [ABSTRACT FROM AUTHOR]