Defining Seafood Safety in the Anthropocene

Predicting essential and hazardous element concentrations in marine fish from the Northeast Atlantic Ocean: A Bayesian approach

Micronutrient deficiency or 'hidden hunger' is of growing importance regionally and globally. Marine fish have the potential to mitigate hidden hunger although certain contaminants they often contain may also pose a health risk. Understanding biological and environmental drivers behind essential and hazardous element concentrations is therefore important to develop evidence-based advice for adaptive management strategies. We use Bayesian models to predict concentrations of ten essential and two hazardous elements in fillets of 14 marine fish species in the Northeast Atlantic Ocean. Data from 15,709 individuals of six lean, five semi-fatty, and three fatty species were included. Fish length, fat content, ocean basin, sea temperature and salinity were used as predictor variables. We found good model predictability and identified some important trends in driver effects. Fish length was the most important driver of element concentrations for most species with a negative effect for calcium, copper, manganese, and arsenic, and a positive effect for mercury, suggesting that smaller individuals may be a safer and better source of essential elements. Ocean basin was also an important driver in most cases. For concentrations of selenium, zinc, and mercury, effect sizes of ocean basins increased from north to south for several species. Fat content exhibited a small negative effect on concentrations of calcium, iron, and mercury, and a small positive effect on phosphorus and arsenic concentrations in many species. Temperature showed a small negative effect on zinc concentration for most species, while the effect of salinity varied among species without an apparent trend. This is the first multi-species and multi-element study to investigate drivers of element concentrations in marine fish at a large spatial scale using a Bayesian approach. The robust model predictability indicates the models' potential to further understand nutrient yield dynamics from fisheries, thereby empowering the implementation of informed strategies against hidden hunger.

Travertine deposition rather than tourism activity is the primary contributor to the microplastic risks in alpine karst lakes

Microplastics (MPs) are emerging as anthropogenic vectors to form plastisphere, facilitating microbiome colonization and pathogenic dissemination, thus contributing to environmental and health crises across various ecosystems. However, a knowledge gap persists regarding MPs risks and their driving factors in certain unique and vulnerable ecosystems, such as Karst travertine lakes, some of which are renowned World Natural Heritage Sites under ever-increasing tourism pressure. We hypothesized that tourism activities serve as the most important factor of MPs pollution, whereas intrinsic features, including travertine deposition can exacerbate potential environmental risks. Thus, metagenomic approaches were employed to investigate the geographical distribution of the microbiome, antibiotic resistance genes (ARGs), virulence factor genes (VFGs), and their combined environmental risks in Jiuzhaigou and Huanglong, two famous tourism destinations in Southwest China. The plastisphere risks were higher in Huanglong, contradicting our hypothesis that Jiuzhaigou would face more crucial antibiotic risks due to its higher tourist activities. Specifically, the levels of Lipopolysaccharide Lewis and fosD increased by sevenfold and 20-fold, respectively, from upstream to downstream in Huanglong, whereas in Jiuzhaigou, no significant accrual was observed. Structural equation modeling results showed that travertine deposition was the primary contributor to MPs risks in alpine karstic lakes. Our findings suggest that tourism has low impact on MPs risks, possibly because of proper management, and that travertine deposition might act as an MPs hotspot, emphasizing the importance of considering the unique aspects of travertine lakes in mitigating MPs pollution and promoting the sustainable development of World Natural Heritage Sites.

Multi-isotopic composition of brown crab (Cancer pagurus) and seafloor sediment from a mine tailing sea disposal impacted fjord ecosystem

Sea disposal of mine tailings in fjord ecosystems is an important coastal management issue in Norway and occurs at the land-sea interface. Here we studied accumulation of heavy metals in brown crab (Cancer pagurus) and seafloor sediment from Jøssingfjord, Norway during 2018 to evaluate long-term, legacy pollution effects of coastal mine tailing sea disposal activities. Nickel and copper sediment pollution in the mine tailing sea disposal area was classified as moderate and severe, respectively, under Norwegian environmental quality standards, and highlights the persistent hazard and legacy impacts of heavy metals in these impacted fjord ecosystems. Mercury, zinc, and arsenic had stronger affinities to brown crab muscle likely due to the presence of thiols, and availability of metal binding sites. Our multi-isotopic composition data showed that lead isotopes were the most useful source apportionment tool for this fjord. Overall, our study highlights the importance and value of measuring several different heavy metals and multiple isotopic signatures in different crab organs and seafloor sediment to comprehensively evaluate fjord pollution and kinetic uptake dynamics. Brown crabs were suitable eco-indicators of benthic ecosystem heavy metal pollution in a fjord ecosystem still experiencing short- and long-term physical and chemical impacts from coastal mining sea disposal activities.

Climate change dynamics and mercury temporal trends in Northeast Arctic cod (Gadus morhua) from the Barents Sea ecosystem

The Northeast Arctic cod (Gadus morhua) is the world's northernmost stock of Atlantic cod and is of considerable ecological and economic importance. Northeast Arctic cod are widely distributed in the Barents Sea, an environment that supports a high degree of ecosystem resiliency and food web complexity. Here using 121 years of ocean temperature data (1900-2020), 41 years of sea ice extent information (1979-2020) and 27 years of total mercury (Hg) fillet concentration data (1994-2021, n = 1999, ≥71% Methyl Hg, n = 20) from the Barents Sea ecosystem, we evaluate the effects of climate change dynamics on Hg temporal trends in Northeast Arctic cod. We observed low and consistently stable, Hg concentrations (yearly, least-square means range = 0.022-0.037 mg/kg wet wt.) in length-normalized fish, with a slight decline in the most recent sampling periods despite a significant increase in Barents Sea temperature, and a sharp decline in regional sea ice extent. Overall, our data suggest that recent Arctic amplification of ocean temperature, "Atlantification," and other perturbations of the Barents Sea ecosystem, along with rapidly declining sea ice extent over the last ∼30 years did not translate into major increases or decreases in Hg bioaccumulation in Northeast Arctic cod. Our findings are consistent with similar long-term, temporal assessments of Atlantic cod inhabiting Oslofjord, Norway, and with recent investigations and empirical data for other marine apex predators. This demonstrates that Hg bioaccumulation is highly context specific, and some species may not be as sensitive to current climate change-contaminant interactions as currently thought. Fish Hg bioaccumulation-climate change relationships are highly complex and not uniform, and our data suggest that Hg temporal trends in marine apex predators can vary considerably within and among species, and geographically. Hg bioaccumulation regimes in biota are highly nuanced and likely driven by a suite of other factors such as local diets, sources of Hg, bioenergetics, toxicokinetic processing, and growth and metabolic rates of individuals and taxa, and inputs from anthropogenic activities at varying spatiotemporal scales. Collectively, these findings have important policy implications for global food security, the Minamata Convention on Mercury, and several relevant UN Sustainable Development Goals.

Phosphorus recovery from high solid content liquid fraction of digestate using seawater bittern as the magnesium source

Phosphorus recovery from digestate is considered a challenge because the possible discharge can lead to eutrophication. This study focuses on phosphorus recovery as struvite from the liquid fraction of swine manure digestate at a high total solids concentration, by using a lab-scale crystallizer operated in continuous mode (7 L·d^-1). A by-product of salt production (seawater bittern, SWB) was assessed as Mg source for the formation of struvite instead of a chemical dosage (MgCl₂) within a circular economy approach. Different Mg/P (1.8:1; 2:1; 3:1) ratios and different TS contents (TS 3.5 and 4.5 %) were studied. The maximum P recovery of 85 % and N recovery of 52 % was obtained at 4.5 % of TS and Mg/P ratio of 2:1, corresponding to an overall P and N recovery on the raw digestate of 70 % and 46 %, respectively. The presence of struvite was confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM-EDS). Dried samples were then used as fertilizer in agronomic pot tests using Brassica rapa chinensis. Struvite obtained, showed comparable fertilizing properties in comparison with conventional fertilizers in terms of P (Mineral 5.6 ± 0.4; Poultry 5.7 ± 0.2; Struvite 5.9 ± 0.1 g kg^-1), N and total biomass content such as chlorophylls ratio. The growth tests confirmed the possible use of struvite recovered as competitive alternative to conventional chemical phosphate fertilizers. The results showed that it can be possible to promote sustainable P recovery from high solids digestates by the combination of crystallizer reactor and Mg-salt byproducts.

Ratiometric Monitoring of Biogenic Amines by a Simple Ammonia-Response Aiegen

Herein, we developed a paper-based smart sensing chip for the real-time, visual, and non-destructive monitoring of food freshness using a ratiometric aggregation-induced emission (AIE) luminogen (i.e., H+MQ, protonated 4-(triphenylamine)styryl)quinoxalin-2(1H)-one) as pH sensitive indicators. Upon exposure to amine vapors, the deprotonation of H+MQ occurs and triggers its color change from blue to yellow, with the fluorescence redshift from blue to amaranth. Consequently, we successfully achieved the sensitive detection of ammonia vapors by recording the bimodal color and fluorescence changes. Given the high sensitivity of H+MQ to ammonia vapor, a paper-based smart sensor chip was prepared by depositing H+MQ on the commercial qualitative filter paper through a physical deposition strategy. After being placed inside the sealed containers, the developed H+MQ-loaded paper chip was applied to the real-time monitoring of biogenic amine contents according to its color difference and ratio fluorescence change. The detection results were further compared with those obtained by the high-performance liquid chromatography method, which verified the feasibility of the designed paper chip for the food spoilage degree evaluation. Briefly, this work indicates that the designed H+MQ-loaded paper chip could be a promising approach for improving food freshness monitoring.

Spontaneous nutrient recovery and disinfection of aquaculture wastewater via Mg-coconut shell carbon composites

Aquaculture wastewater contained large amounts of pathogenic microorganisms, nitrogen (N) and phosphorus (P). In this study, the nutrient recoveries and wastewater disinfection were simultaneously achieved using Mg-coconut shell carbon (Mg-CSC). The composites were prepared by a ball milling method. The hydrogen peroxide (H₂O₂) was in-situ generated by the dissolved oxygen reduction driven by Mg corrosion on the CSC surface, which inactivated the microorganisms. Besides that, Mg corrosion provided sufficient Mg ions and appropriate pH conditions for struvite formation. The results show that 5.4-log E.coli removal was achieved under different conditions. Improving the Mg/CSC ratio and composite dosage could shorten the time required for disinfection. In addition to H₂O₂, singlet oxygen played a critical role. Reactive oxygen species destroyed the cellular structure and killed the bacteria. The recoveries of NH₄⁺-Nand P under certain conditions were about 60% and 91%, respectively. An increased composite dosage could improve the recovery ratio of P. Excessive dosages were not beneficial for removing NH₄⁺-N. The characterization result revealed that struvite crystals were the main precipitates on the CSC surface. The Mg-CSC composites also revealed satisfied nutrient recovery and disinfection performances in the real aquaculture wastewater treatment process.

Influence of phosphorus on the uptake and biotransformation of arsenic in Porphyra haitanensis at environmental relevant concentrations

Edible seaweeds are rich in essential vitamins and minerals, which made them a popular food worldwide. Porphyra haitanensis is one of the most commonly consumed seaweeds with the known ability to accumulate a high level of total arsenic (As). A large number of articles have shown arsenic and phosphorus (P) interactions in microalgae due to the plant's inability to differentiate arsenate from phosphate. However, very limited information is available for edible seaweed at environmentally relevant concentrations. In this study, P. haitanensis was treated with arsenic as As^V (As1: 0.06 μM, As2: 0.4 μM, As3: 1.2 μM) and phosphorous (P1: 3.2 μM, P2: 13 μM) in a filtered seawater matrix under laboratory condition for six days. A better growth rate was found in seaweeds grown in P2 treatments. Moreover, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content measurements revealed that a higher P concentration prevent seaweeds from lipid peroxidation and oxidative stress. Transcriptome studies indicated the As replacement to P has the ability to target seaweed cell membrane composition, transmembrane transport, DNA and ATP binding. The inorganic As (iAs) had a concentration of 0.54 to 4.45 mg/kg in P. haitanensis on Day 6 with As1, As2, and As3 treatments under low P regime (P1), which exceeds the limits of iAs concentration (0.1-0.5 mg/kg) in National Food Safety Standard-Limits of Pollutants in Food (GB 2762-2017). High P regime (P2) not only reduced the total As but also iAs effectively, even in the highest As treatment (As3), the iAs concentration was less than 0.5 mg/kg on Day 6. These findings provide a good insight for seafood safety guarantees and are important for the management of coastal artificial seaweed farming.

Co-occurrence of contaminants in marine fish from the North East Atlantic Ocean: Implications for human risk assessment

Marine fish from the North East Atlantic Ocean (NEAO) are nutrient rich and considered a valuable economic resource. However, marine fish are also a major dietary source of several contaminants, including persistent organic pollutants (POPs) and heavy metals. Using one of the world's largest seafood datasets (n > 25,000 individuals), comprising 12 commercially important fish species collected during 2006-2019 in the NEAO, we assessed the co-occurrence of elements and POPs, and evaluated potential risks to human consumers. Several positive correlations between concentrations of mercury (Hg), dioxins, polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were observed. Concentrations of Hg, dioxins, PCBs and PBDEs increased from North to South and associations between marine sediment contamination, sea temperature, and fish Hg and POPs concentrations were identified using multi-linear regression (MLR) models. In general, Hg concentrations in fillet and liver of fish were positively associated with increases in both sediment contamination and sea temperature. POPs concentrations in both fillet and liver were positively associated with increases in sediment contamination, and only POPs concentrations in the liver of benthopelagic and demersal species were found to be positively correlated with sea temperature. Using a probabilistic approach to estimate human contaminant exposure from seafood, we showed that intake of pelagic species posed the highest risk of dioxins and dioxin-like PCBs (DL-PCBs) exposure, while intake of benthopelagic and demersal species posed the highest risk of Hg exposure. This study can serve as a model to further understand the distribution, co-occurrence, and trends of contaminants in seafood harvested from the NEAO and their potential risks to human consumers.