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In recirculating aquaculture systems (RAS), off‐flavours accumulated in fish muscle tissue can be problematic in terms of consumer acceptance and the reputation of farmed fish products. Off‐flavours often give fish earthy, muddy, or other undesirable flavours. Typically, off‐flavours are removed during a depuration period in which fish are fasted and held in clean water. Unfortunately, this causes additional costs and delayed sales, while fish lose weight and show a decrease in lipid content. First, we studied fish growth in a partial RAS (PRAS) where the conditions are very similar to those in depuration with a water exchange rate of 4000 L kg−1 feed, compared to RAS with a 650‐L water kg−1 feed. Rainbow trout (Oncorhynchus mykiss) was reared in both systems. Our aim was to combine the benefits of a higher water exchange rate: the lack of need for biofilters and a lower accumulation of off‐flavours while obtaining stable rearing conditions. Additionally, we studied the effects of moderate feeding and H2O2 addition during depuration. The fish grew faster in a PRAS than in a RAS when fed ad libitum. Thirteen off‐flavour compounds were found in the fish flesh and 11 in the circulating water. The H2O2 addition led to decreased levels of off‐flavours in the tank water and in fish muscle. The results showed no significant differences in off‐flavours between the fed and not‐fed systems, showing that moderate feeding did not prevent a good depuration result. However, the lipid content and the overall fish weight were higher in the fed systems, which suggests more effective depuration. Increased depuration efficiency can be an important tool when considering ways to improve the profitability of production. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a toxic heavy metal that, when present as a pollutant in the marine environment, is readily accumulated by marine bivalves, causing oxidative stress and tissue damage. This study explored whether short-term depuration could reverse Cd2+-induced toxicity in the ovary of the clam Meretrix meretrix. Clams exposed to 3 mg L-1 Cd2+ for three days showed increased accumulated Cd2+ in their ovaries with obvious tissue damage as shown by loose structure and some apoptotic cells compared with non-exposed clams. Increased oxidative stress in the ovarian tissue was also obvious, as revealed by increased levels of oxidative indicators such as reactive oxygen species (ROS), malondialdehyde (MDA), DNA-protein crosslinking (DPC), and protein carbonylation (PCO) and increased expression levels of genes related to oxidative stress and apoptosis, which included the Bax, Bcl-2, caspase-3, HO-1, Hsp70, NQO1, Nrf2, and MT genes. When the clams were exposed to Cd2+ for three more days, the accumulated Cd2+ level in the ovary increased to more than 10-fold the level in the control clams, accompanied by more severe damage and cell death as well as oxidative stress. However, when the initial three-day Cd2+ exposure was followed by three days of depuration in Cd2+-free seawater, the Cd2+ level in the ovary was reduced by as much as 20%, accompanied by some recovery of tissue damage and reduced oxidative stress, suggesting that short-term depuration may mitigate Cd2+-induced toxicity in M. meretrix, allowing the clams to recover and potentially reducing the risk of Cd2+ exposure from consuming contaminated clams. [ABSTRACT FROM AUTHOR]

The dieback disease is caused by the phytopathogen Lasiodiplodia theobromae that affects farmer's production; it is characterized by its ability to survive through pycnidia and chlamydospores in soil and crop residues, it spreads to plant tissues to remain endophytic until the host crop becomes vulnerable by mechanical damage or nutrient deficiency leading to death of young branches, mummification and fruit rot. Due to the persistent mode of L. theobromae, the research focused on the simultaneous depuration of strains of the phytopathogen isolated from banana and raspberry with the objective of detecting the mycelial growth rate against fungicides of different mode of action, establishing by means of a toxicity scale at one of the concentrations 10; 1; 0,1; 0,01 and 0,001 µg mL-1 as efficient with propiconazole, mancozeb, iprodione, difenoconazole and cyproconazole, respectively in their order. There was 100% growth inhibition with propiconazole and difenoconazole at a concentration of 10 µg mL-1 that allows them to be effective fungicides in the control of the phytopathogen, while mancozeb, iprodione and cyproconazole were harmless to L. theobromae, because they allowed its mycelial growth in the research. [ABSTRACT FROM AUTHOR]

This study evaluated the pharmacokinetic profile of basil (Ocimum basilicum) essential oil (EO) in juvenile tambaqui (Colossoma macropomum). In trial I, juvenile tambaqui (119.9 ± 9.2 g) were exposed to 800 mg L−1 of EO for 10 min for anesthetic induction. After the blood samples, muscle and brain tissue samples were collected at 2, 4, 6, 8, and 10 min to determine the absorption time and distribution of methyl chavicol and linalool, the major compounds in the EO, the concentration of lactate and ammonia in the muscles, and the plasma levels of lactate, chloride, ammonia, and total calcium. In trial II, anesthetic induction occurred at the same time and concentration and blood, muscle, and brain tissue samples were collected at 0.0, 0.5, 1.0, 3.0, and 6.0 h to quantify the elimination of methyl chavicol and linalool and for a histological evaluation of the gills, liver, and spleen. In assay I, both compounds were identified in the plasma, muscle, and brain as early as 2 min, with maximum concentrations observed within 6 min. In assay II, the half-life of methyl chavicol and linalool in plasma was 0.30 h and 0.46 h, respectively. The half-life of methyl chavicol and linalool in muscle was 1.59 h and 0.32 h, respectively, and the half-life of methyl chavicol and linalool in the brain was 0.69 h and 0.33 h, respectively. The histological lesions observed in the gills between 0 and 3 h were reversible, with organ recovery 6 h after anesthesia induction. There were no changes in the liver and spleen during the times evaluated. The biochemical and pharmacokinetic results in this study confirm that the EO of O. basilicum at 800 mg L−1 is a safe anesthetic for tambaqui, inhibits the stress response, and is eliminated rapidly from the fish. [ABSTRACT FROM AUTHOR]

Insecticides prevent or reduce insect crop damage, maintaining crop quality and quantity. Physiological traits, such as an insect's feeding behavior, influence the way insecticides are absorbed and processed in the body (toxicokinetics), which can be exploited to improve species selectivity. To fully understand the uptake of insecticides, it is essential to study their total uptake and toxicokinetics independent of their toxic effects on insects. We studied the toxicokinetics (TK) of insecticidally inactive test compounds incorporating agro-like structural motifs in larvae of the Egyptian cotton leafworm (Spodoptera littoralis, Lepidoptera), and their distribution across all biological matrices, using laboratory experiments and modeling. We measured Spodoptera larval behavior and temporal changes of whole-body concentrations of test compounds during feeding on treated soybean leaf disks and throughout a subsequent depuration period. Differences in the distribution of the total quantities of compounds were found between the biological matrices leaf, larva, and feces. Rate constants for uptake and elimination of test compounds were derived by calibrating a toxicokinetic model to the whole-body concentrations. Uptake and elimination rate constants depended on the physicochemical properties of the test compounds. Increasing hydrophobicity increased the bioaccumulation potential of test compounds. Incomplete quantities in larval matrices indicated that some compounds may undergo biotransformation. As fecal excretion was a major elimination pathway, the variable time of release and number of feces pellets led to a high variability in the body burden. We provide quantitative models to predict the toxicokinetics and bioaccumulation potential of inactive insecticide analogs (parent compounds) in Spodoptera. [ABSTRACT FROM AUTHOR]

Microplastics (MPs, ＜5mm in size) have rapidly spread across aquatic ecosystems, which urgently needs systematic assessment for their ecological risk. Fish species have frequently been selected as indicator organisms in evaluating MPs contaminants. However, it has been questioned that which organs of fishes should be examined due to tissue-specific results. In this study, we investigated the accumulation and depuration process of MPs in the main organs of zebrafish under different MPs concentrations as well as the presence and absence of food resources. Our results recorded consistently higher MPs accumulation in fish guts among different MPs concentrations, implying fish guts as stable organs representing organisms’ MPs contaminants. Meanwhile, MPs accumulated in fish guts increased significantly with increasing exposure concentrations, highlighting fish guts as sensitive organs in reflecting MPs contamination in aquatic environments. In addition, MPs accumulated in fish guts under non-feeding conditions followed a logistic “S” curve while fluctuated under feeding conditions, suggesting increased ecological MPs risk with the absence of food resources. The depuration rate in fish guts was significantly higher in the feeding group than in the non-feeding group, implying better expelling ability of MPs with the presence of food resources. Our study proposes fish guts as the optimal indicator organs in assessing the ecological risk of MPs contaminants in both fish bodies and aquatic environments, and highlights the importance of sustaining sufficient food resources in aquatic environments to reduce the MPs triggered adverse effects on fish species.

ABSTRACT In recirculating aquaculture systems (RAS), off‐flavours accumulated in fish muscle tissue can be problematic in terms of consumer acceptance and the reputation of farmed fish products. Off‐flavours often give fish earthy, muddy, or other undesirable flavours. Typically, off‐flavours are removed during a depuration period in which fish are fasted and held in clean water. Unfortunately, this causes additional costs and delayed sales, while fish lose weight and show a decrease in lipid content. First, we studied fish growth in a partial RAS (PRAS) where the conditions are very similar to those in depuration with a water exchange rate of 4000 L kg−1 feed, compared to RAS with a 650‐L water kg−1 feed. Rainbow trout (Oncorhynchus mykiss) was reared in both systems. Our aim was to combine the benefits of a higher water exchange rate: the lack of need for biofilters and a lower accumulation of off‐flavours while obtaining stable rearing conditions. Additionally, we studied the effects of moderate feeding and H2O2 addition during depuration. The fish grew faster in a PRAS than in a RAS when fed ad libitum. Thirteen off‐flavour compounds were found in the fish flesh and 11 in the circulating water. The H2O2 addition led to decreased levels of off‐flavours in the tank water and in fish muscle. The results showed no significant differences in off‐flavours between the fed and not‐fed systems, showing that moderate feeding did not prevent a good depuration result. However, the lipid content and the overall fish weight were higher in the fed systems, which suggests more effective depuration. Increased depuration efficiency can be an important tool when considering ways to improve the profitability of production.

Marine toxins pose a significant safety risk, leading to human intoxications and causing substantial economic losses in seafood-producing regions. The development of rapid, cost-effective, efficient, and reliable approaches for the containment of these substances is therefore crucial in order to mitigate the adverse impact of marine toxins. This research conducted a comprehensive review on the toxicity and influencing factors of marine toxins production. Additionally, depuration technologies, including adsorption, advanced oxidation processes, biodegradation, heating treatment, temporary maintenance and purification, and drug inhibition, were systematically summarized. The study also provided a comparative analysis of the advantages and disadvantages of various depuration technologies and proposed strategies for future development.

Depuration is a proven pre-harvest procedure that eliminates off-flavor from Atlantic salmon produced in recirculating aquaculture systems. However, applied research indicates that depurating salmon lose weight while fasting, which reduces farmgate revenue. Low-ration feeding was therefore evaluated as a method to mitigate weight loss while depurating 3–4 kg Atlantic salmon. Salmon implanted with passive-integrated-transponders were weighed, exposed to concentrated geosmin (GSM) and 2-methylisoborneol (MIB), and stocked in eight pre-disinfected partial reuse systems. Feed was either offered for 4 days or withheld entirely (n = 4) during a 6-day depuration period. Salmon from both treatments rapidly eliminated GSM and MIB, but slightly lower levels remained in fish that were fed (P <.05). Fed and fasted salmon lost 0.3 and 1.1% of their initial body weight, respectively (P <.05). Under the conditions of this study, feeding Atlantic salmon during depuration minimized weight loss without negatively impacting off-flavor elimination. [ABSTRACT FROM AUTHOR]

Crayfish rely on their chemosensory system for many essential behaviours including finding food, finding mates, and to recognize individuals. Copper can impair chemosensation in crayfish at low concentrations; however, it is not clear if the effect is ameliorated once copper is removed. To better understand the effect of and recovery from copper exposure in crayfish, we exposed Northern clearwater crayfish (Faxonius propinquus) to 31.3 copper for 24 h and measured the response of the crayfish to a food cue. The crayfish were then placed into clean water to depurate for an 24 h. The results demonstrated that the crayfish did not respond to a food cue if they had been exposed to copper, but showed a full response after a 24 h recovery period without copper. Higher concentrations of copper have shown a much longer-term effect in rusty crayfish (Faxonius rustics), indicating there is a concentration where the copper is causing longer-term damage instead of just impairing chemosensation. These results highlight the fact that even though contaminants like copper can have profound effects at low concentrations, by removing the contaminants the effect can be ameliorated. [ABSTRACT FROM AUTHOR]

In Iran’s legal system, the "Codification" (کودیفکاسیون (was initially used without any translation into Persian in Article 4 of the "Regulations for the Establishment of Consultative Commissions on Legal Administration" (1963). Later, it was translated into Persian as "Tanqih" and "Tadwin" due to the lack of an exact equivalent in Persian. The use of these two words for translation of codification, led to a significant challenge in the legislative system, as it was believed that "Tanqih" referred to "Depuration" or distinguishing valid from invalid laws and regulations, while "Tadwin" referred to "Compilation" or preparation of legal collections. This resulted in confusion and misunderstanding, causing the concept of "Codification" to be forgotten for decades. This article aims to correct the interpretation and presentation of the claim that the Incorrect translation and interpretation of the term “codification”, has resulted in an excessive emphasis on these two terms, leading to neglect of the actual process of "Codification". This has prevented Iran's legal system from focusing on the ultimate goal, which is the “Code”. Through a comparative study, this article examines and discusses the concept, elements, characteristics, and product of the process of codification. It is based on the authors' studies and experiences in codifying "Iran’s Health Code." [ABSTRACT FROM AUTHOR]

The global consumption of antibiotics leads to their possible occurrence in the environment. In this context, nature-based solutions (NBS) can be used to sustainably manage and restore natural and modified ecosystems. In this work, we studied the efficiency of the NBS free-water surface wetlands (FWSWs) using Eichhornia crassipes in microcosm for enrofloxacin removal. We also explored the behavior of enrofloxacin in the system, its accumulation and distribution in plant tissues, the detoxification mechanisms, and the possible effects on plant growth. Enrofloxacin was initially taken up by E. crassipes (first 100 h). Notably, it accumulated in the sediment at the end of the experimental time. Removal rates above 94% were obtained in systems with sediment and sediment + E. crassipes. In addition, enrofloxacin was found in leaves, petioles, and roots (8.8–23.6 µg, 11–78.3 µg, and 10.2–70.7 µg, respectively). Furthermore, enrofloxacin, the main degradation product (ciprofloxacin), and other degradation products were quantified in the tissues and chlorosis was observed on days 5 and 9. Finally, the degradation products of enrofloxacin were analyzed, and four possible metabolic pathways of enrofloxacin in E. crassipes were described. [ABSTRACT FROM AUTHOR]

Simple Summary: Microplastics are an environmental pollutant increasingly present in seawater, the spread of which also represents a threat to food safety. In fact, these particles can be ingested through various foods, among the most at risk are bivalve molluscs, as they filter large quantities of seawater and enter the diet of consumers ingested entirely. Purification studies of bivalves could allow us to understand in a more precise way the ability of organisms to eliminate microplastics, in order to test this process as a potential method of removing such contaminants from bivalves intended for human consumption. Microplastic contamination is a growing marine environmental issue with possible consequences for seafood safety. Filter feeders are the target species for microplastic (MPs) pollution because they filter large quantities of seawater to feed. In the present study, an experimental contamination of Mytilus galloprovincialis was conducted using a mixture of the main types of MPs usually present in the seawater column (53% filaments, 30% fragments, 3% granules) in order to test the purification process as a potential method for removing these contaminants from bivalves intended for human consumption. A set of molecular biomarkers was also evaluated in order to detect any variations in the expression levels of some genes associated with biotransformation and detoxification, DNA repair, cellular response, and the immune system. Our results demonstrate that: (a) the purification process can significantly reduce MP contamination in M. galloprovincialis; (b) a differential expression level has been observed between mussels tested and in particular most of the differences were found in the gills, thus defining it as the target organ for the use of these biomarkers. Therefore, this study further suggests the potential use of molecular biomarkers as an innovative method, encouraging their use in next-generation marine monitoring programs. [ABSTRACT FROM AUTHOR]

Waste solutions from the electrolytic production of copper contain significant amounts of copper and nickel sulfates, sulfuric acid, arsenic and other components of the copper electrolyte. The processing of such solutions is considered in this work not only from the point of view of environmental protection, but also in terms of extracting various valuable components from the electrolyte into commercial products. A thermodynamic analysis of the interactions between barium and arsenic, as well as their compounds in the Ba(AsO2)2-Ba3(AsO4)2-H2O system was carried out based on the E-pH diagram. The possibility of using barium compounds as a precipitant for arsenic from copper electrorefining solutions has been demonstrated. The efficiency of removing arsenic (more than 84%) from the electrolyte using barium oxide in the form of sparingly soluble barium arsenate has been established. By adding calculated amounts of zinc oxide into the working solution, it is possible to form solutions containing certain concentrations of Cu, Ni, and Zn. By further adding zinc oxide into the solution, its deep dehydration was achieved. The resulting copper-nickel-zinc and nickel-zinc solutions are the raw material for producing non-ferrous metal alloys using the electromembrane method. [ABSTRACT FROM AUTHOR]

Aquatic animals are prone to extinction due to metal pollution and global climate change. Even though the fish and their products are also unsafe for human consumption, their exports have been rejected due to inorganic and organic contaminants. Nickel (Ni) is a metal that induces toxicity and accumulates in the aquatic ecosystem, posing health threats to humans, animals, and fish. In light of the above, our present investigation aimed to determine the median lethal concentration (96 h-LC50) of nickel alone and concurrent with high temperature (34 °C) (Ni + T) using static non-renewable bioassay toxicity test in Pangasianodon hypophthalmus. The groups treated under exposure to Ni reared under control condition (25–28.9 °C) and Ni + T exposure group reread under 34 °C. In this study, chose the definitive dose of Ni and Ni + T as 17, 18, 19, and 20 mg L−1 after the range finding test. The median lethal concentration of Ni and Ni + T was determined as 19.38 and 18.75 mg L−1, respectively at 96 h. Oxidative stress viz. catalase (CAT), superoxide dismutase (SOD), glutathione-s-transferase (GST), and glutathione peroxidase (GPx) in the liver, gill, and kidney were noticeably elevated with Ni and Ni + T during 96 h. Whereas, the CAT, GPx, and SOD gene expressions were significantly upregulated with Ni and Ni + T. Trilox equivalent anti-oxidant capacity (TEAC), cupric reducing anti-oxidant capacity (CUPRIC), ferric reducing ability of plasma (FRAP), ethoxy resorufin-O-deethylase (EROD), and acetylcholine esterase (AChE) were reduced due to exposure to Ni and Ni + T. Cellular metabolic stress and lipid peroxidation were highly affected due to Ni and Ni + T exposure. The immunological status, as indicated by total protein, albumin, globulin, A:G ratio, and nitro blue tetrazolium chloride (NBT), was severely affected by the toxicity of Ni and Ni + T. Moreover, the gene expression of interleukin (IL), tumor necrosis factor (TNFα), toll-like receptor (TLR), and total immunoglobulin (Ig) was remarkably downregulated following exposure to Ni and Ni + T. HSP 70, iNOS expression, ATPase, Na + /K + -ATPase, cortisol, and blood glucose was significantly elevated with Ni and Ni + T in P. hypophthalmus. The bioaccumulation of Ni in fish tissues and experimental water was determined. The kidney and liver tissues were highly accumulated with Ni, whereas DNA damage was reported in gill tissue. Interestingly, depuration study revealed that at the 28th day, the Ni bioaccumulation was below the maximum residue limit (MRL) level. Therefore, the present study revealed that Ni and Ni + T led to dysfunctional gene and metabolic regulation affecting physiology and genotoxicity. The bioaccumulation and depuration results also indicate higher residual occurrence of Ni in water and aquatic organisms for longer periods. [ABSTRACT FROM AUTHOR]

Abstract Studies investigating microplastics (MPs) in marine species have been published over recent decades, including studies on depuration efficacy on aquaculture products. This preliminary study investigates the depuration efficacy of MPs in two commercial oyster species from Ireland. The innovative aspects are the sampling size (n = 50 per species) and the experiment duration (up to 96 h). The case study organisms are the Pacific oyster (Magallana gigas) and the European flat oyster (Ostrea edulis). Prior to depuration, the mean MP concentration on M. gigas edible tissue was 0.6 MP g−1 while for O. edulis was 0.4 MP g−1. Significant differences in mean MP concentrations were identified after 96‐h for M. gigas 0.2 MP g−1 (p = 0.014) and O. edulis, 0.1 MP g−1 (p = 0.003). Additionally, no significant correlation was established between MP concentrations and edible tissue weight. Polymer identification revealed that 51.6% were fibers of natural origin. Preliminary results show that increasing depuration times beyond 72‐h can significantly reduce MPs in selected oyster species, which is what is being recommended with this baseline study. Further investigation on commercial conditions at adequate depuration facilities is required. Given the relevance of low‐trophic aquaculture species for local economies, this preliminary study provides important baseline information for stakeholders.

In this study, we evaluated the use of hydrolates, co-products of essential oil distillation, as processing aids to improve the depuration process of Pacific oysters (Crassostrea gigas) as a post-harvest method aimed at reducing the norovirus (NoV) viral load. Live oysters were kept in water to which hydrolates of Thymus serpyllum and Citrus limon at 1% were added for 24 h. The concentration of NoV was quantified using the ISO 15216-1 quantitative real-time RT-PCR method in the oyster digestive tissue both before and after the treatment. The results showed a significant reduction of 0.2 log in the NoV GII concentration after 24 h of treatment with 1% C. limon hydrolate. Conversely, treatment with T. serpyllum did not appear to reduce the concentration of NoV compared to the control. Additionally, a sensory analysis was conducted through a blind survey comparing untreated and treated oysters. No changes in the sensory and physical characteristics of the oysters were observed, except for a decrease in the marine flavour intensity, which was positively perceived by consumers. These results indicate that the addition of hydrolates of C. limon at 1% during depuration might represent a promising processing aid for enhancing both the safety and acceptability of live oysters. [ABSTRACT FROM AUTHOR]

Fat deposition and off-flavor in the muscle are the main problems affecting flesh quality in aquaculture fish, especially in catfish, leading to low acceptability and reduced market price. Yellow catfish is an important aquaculture fish in China. In this study, 40 days of depuration and starvation treatment were explored to improve the muscle quality of aquaculture yellow catfish. After depuration and starvation, the body weight, condition factor (CF) and mesenteric fat index (MFI) were all significantly decreased 20 days after treatment. The metabolomic profiles in muscle were characterized to analyze the muscle quality in yellow catfish. The results showed that the content of ADP, AMP, IMP, glutamic acid and taurine were significantly increased between 20 and 40 days post-treatment in the muscle of yellow catfish during the treatment, which was positively associated with the flesh tenderness and quality. In contrast, aldehydes and ketones associated with off-flavors and corticosterone associated with bitter taste were all decreased at 20 days post-treatment. Considering the balance of body weight loss and flesh quality improvement, depuration and starvation for around 20 days is suitable for aquaculture yellow catfish. Our study not only provides an effective method to improve the flesh quality of aquaculture yellow catfish but also reveals the potential mechanism in this process. [ABSTRACT FROM AUTHOR]

Studies investigating microplastics (MPs) in marine species have been published over recent decades, including studies on depuration efficacy on aquaculture products. This preliminary study investigates the depuration efficacy of MPs in two commercial oyster species from Ireland. The innovative aspects are the sampling size (n = 50 per species) and the experiment duration (up to 96 h). The case study organisms are the Pacific oyster (Magallana gigas) and the European flat oyster (Ostrea edulis). Prior to depuration, the mean MP concentration on M. gigas edible tissue was 0.6 MP g−1 while for O. edulis was 0.4 MP g−1. Significant differences in mean MP concentrations were identified after 96‐h for M. gigas 0.2 MP g−1 (p = 0.014) and O. edulis, 0.1 MP g−1 (p = 0.003). Additionally, no significant correlation was established between MP concentrations and edible tissue weight. Polymer identification revealed that 51.6% were fibers of natural origin. Preliminary results show that increasing depuration times beyond 72‐h can significantly reduce MPs in selected oyster species, which is what is being recommended with this baseline study. Further investigation on commercial conditions at adequate depuration facilities is required. Given the relevance of low‐trophic aquaculture species for local economies, this preliminary study provides important baseline information for stakeholders. [ABSTRACT FROM AUTHOR]

Hexabromocyclododecanes (HBCDs), as brominated flame retardants, have increasingly drawn concern due to their detection in various marine organisms in recent years. The present test investigated the selective accumulation, depuration, and bioisomerization of HBCDs in different tissues and organs of Nibea albiflora, as well as the genetic metabolic behavior of HBCDs between parents and offspring. In a semi-static water environment, N. albiflora were exposed to individual HBCD diastereoisomers (α-HBCD, β-HBCD, or γ-HBCD) at a concentration of 0.4 μg/L for bioaccumulation, followed by clean food for depuration. During the exposure period, the highest concentrations of these HBCDs were observed in the intestine and gill of N. albiflora. α-HBCD was detected in all exposure groups, suggesting that both β-HBCD and γ-HBCD could be bioisomerized to α-HBCD in N. albiflora. In addition, there was no bioisomerization of α-HBCD to either β-HBCD or γ-HBCD, and there was no bioisomerization between β-HBCD and γ-HBCD. The half-lives (t1/2) were variable among different diastereoisomers, following an order of α-HBCD > γ-HBCD > β-HBCD. The most rapid depuration rate of HBCDs was discovered in the liver while muscle showed the least. Additionally, prior to spawning, the parent fish were exposed to contaminated feed (silkworms sprayed with 200 μL of a 30 μg/mL HBCD solution) for 6 days. By comparing the HBCDs concentrations in the maternal gonad, fertilized eggs, hatching eggs, larvae, and juveniles, it was determined that the maternal transfer coefficients for HBCDs were approximately 1, indicating dynamic equilibrium of HBCDs throughout the process from maternal tissue to progeny development. Differences in HBCDs pattern between organs observed in the experiment support a proposal of an organ-specific diastereomer accumulation.

Recently, our in vitro study on the effects of plasma-activated simulated seawater (PASW) demonstrated its potential as a novel, alternative disinfectant in oyster depuration. In this current study, PASW's physicochemical and antimicrobial properties were identified and its effects on oyster quality were observed. Simulated seawater (SS) activated by plasma for 10 min (PASW10) increased in temperature, oxidation reduction potential, and electrical conductivity with a decrease in those parameters after 1:1 dilution with SS (PASW10 (1:1)). The pH decreased immediately after plasma activation and subsequently increased after dilution. Nitrate and nitrite concentrations were higher in PASW10 (1:1) compared to PASW10 (3:1). No free available chlorine was detected in undiluted PASW10. Processing using SS and PASW10 (1:1) depuration and refrigeration of E. coli-bioaccumulated oysters was observed. Significantly higher reductions in total coliform and E. coli were noted for PASW10 (1:1) treated oyster samples after 24 h compared to refrigerated samples. No significant differences in values for condition index or biting force of oyster meats were observed for the processed samples after 24 h. Overall, the novel and environment-friendly PASW could be used as an alternative antimicrobial disinfectant in oyster depuration systems because it does not negatively affect an oyster's viability or quality. [ABSTRACT FROM AUTHOR]

The present investigation carries out a Systematic Review of the scientific Literature to analyze the purification methods of treatment of affluent with a high content of heavy metals that affects metallic structures, reported in the scientific literature. A total of 805 studies obtained from the Scopus, IEEE, Web of Science, Scielo, Elsevier, Springer databases were initially retrieved; with the Google Scholar, Semantic Scholar and IEEE Xplore search engines; Finally, 16 were included in this investigation. As a fundamental result, 12 methods of purification of affluent contaminated with heavy metals were identified. For the present investigation, the conventional treatment methods for developing countries were especially significant. The results obtained in several investigations indicate that metallic structures are affected when they are in contact with tributaries with a high content of heavy metals, mainly when the tributary is related to industrial waters. [ABSTRACT FROM AUTHOR]

Synthetic pyrethroid insecticides (SPIs) are frequently detected in water bodies and sediments, and they show high toxicity to aquatic organisms, but their toxicity kinetics remain unknown. In this work, the kinetics of uptake and depuration of three SPIs, fenpropathrin (FP), cypermethrin (CM) and deltamethrin (DM) were evaluated in manila clams (Ruditapes philippinarum) for the first time through a bioconcentration-semi-static test. Clams were exposed to three SPIs of different concentrations (2 ng/mL and 20 ng/mL) for 4 days, followed by a 10-day depuration stage. The results indicated that adult manila clams could absorb SPIs rapidly, and the bioconcentration factor (BCF) values of SPIs were different at high and low concentrations of contaminants. The depuration rate constants (k2) of SPIs in adult manila clams ranged from 0.024 h-1 to 0.037 h-1. The bioaccumulation factors ranged from 319.41 to 574.38. And the half-lives (t1/2) were in the range of 18.49 to 29.22 h. These results showed that manila clams have a high bioconcentration capacity, and SPIs have a high cumulative risk for bivalves. Moreover, after 10 days of elimination, SPIs can still be detected in manila clams at all concentrations, indicating that the complete elimination of SPIs required a longer time. [ABSTRACT FROM AUTHOR]

The increase in pathogen levels in seawater threatens the safety of entire aquatic ecosystems. Foodborne pathogens can potentially accumulate in shellfish, especially in filter feeders such as bivalves, requiring an efficient depuration process before consumption. Alternative approaches to promote a cost-efficient purge at depuration plants are urgently needed. A small prototype pulsed ultraviolet (PUV) light recirculation system was designed, and its depuration potential was tested in a seawater matrix artificially contaminated with high levels of microbial pathogens Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Bacillus cereus and Candida albicans. The analysis of treatment parameters including voltage, number of pulses and duration of treatment was performed to ensure the highest reduction in contaminant levels. Optimal PUV disinfection was attained at 60 pulses/min at 1 kV for 10 min (a UV output of 12.9 J/cm2). All reductions were statistically significant, and the greatest was observed for S. aureus (5.63 log10), followed by C. albicans (5.15 log10), S. typhimurium (5 log10), B. cereus (4.59 log10) and E. coli (4.55 log10). PUV treatment disrupted the pathogen DNA with the result that S. aureus, C. albicans and S. typhimurium were not detectable by PCR. Regulations were reviewed to address the applicability of PUV treatment as a promising alternative to assist in the reduction of microbial pathogens at depuration plants due to its high efficiency, short treatment period, high UV dose and recirculation system as currently employed in shellfish depuration plants. [ABSTRACT FROM AUTHOR]

Abstract Land‐based Atlantic salmon, Salmo salar, grow‐out facilities utilize depuration to remediate off‐flavor. Water used in this process is either discharged or repurposed as supply water in recirculating aquaculture systems (RAS). Both approaches require an understanding of water quality and waste production for water treatment decisions and compliance with pollution discharge standards; however, these data were lacking. Therefore, a study was carried out to characterize these parameters. To begin, 311 salmon (5–6 kg) originally cultured in freshwater RAS were stocked at 100 kg/m3 in an 18 m3 depuration tank. Feed was withheld 1 day before transfer and throughout the 7‐day study period. Hours after stocking, total suspended solids (TSS), total phosphorus (TP), and total ammonia nitrogen (TAN) levels spiked, and concentrations declined thereafter. Delta TSS and TP were negligible by the end of the trial; however, TAN plateaued, indicating that salmon began to catabolize somatic tissue in the absence of feeding. Geosmin and 2‐methylisoboreol levels in water and fish were low throughout the study. This research indicates that residual waste production occurs while depurating Atlantic salmon. Procedural refinements and recommendations were gleaned including locality for introducing depuration system water within RAS and extension of the feed withholding period before depuration.

This study aimed to reveal the flavor quality changes of live oysters during different steps of circulation, and optimize the management of live oyster transportation in order to improve the survival quality of oysters. The changes in the types and contents of volatile flavor compounds in Crassostrea gigas sequentially subjected to depuration, induced dormancy and simulated waterless live transportation were investigated using solid phase microextraction coupled to gas chromatography-mass spectrometry (SPME-GC-MS). Results showed that a total of 49 volatile flavor substances were identified in live C. gigas, including aldehydes, ketones, esters, hydrocarbons, alcohols, nitrogen-containing and sulfur-containing heterocyclic compounds. Post-harvest stress had a significant impact on the flavor quality. The content of pleasant flavor compounds was significantly enhanced while the content of irritating odor substances was evidently reduced, and lipid oxidation was significantly alleviated after 24 h of depuration. Lipid oxidation in oysters was increased with waterless live transportation time, and the total amount of volatile flavor substances was slowly accumulated. Odor activity values (OAVs) showed that heptanal, nonanal, (E)-2-nonenal, 4-ethylbenzaldehyde, hexanal, (E)-2-octenal, undecanal, (E)-2-decenal, decanal, (E,E)-2,4-nonadienal and 2-pentyl furan were the key flavor substances of live C. gigas, which could be used as a reference to reflect the physiological status of live oysters. Principal component analysis (PCA) showed that the cumulative contribution of the first three principal components to total variances was 85.6%, allowing a clear distinction between the different stages of circulation. In conclusion, the vitality and flavor substances of C. gigas reach a new level after post-harvest depuration for 24 h, which is more conducive to long-term low temperature and waterless live oyster preservation. Meanwhile, the analysis of volatile components can be used as a method to identify the vitality during the circulation of live shellfish.

One of the most important aquatic macro-invertebrates is Procambarus clarkii. This study was designed to evaluate the effect of depuration for 21 days on the total hemocytes count and heavy metals (Co, Cr, Pb and Hg) concentrations in the hemolymph and different tissues of P. clarkii. Two hundred crayfish were collected and were divided into two groups; field crayfish (FCF) that were dissected directly and the depurated crayfish (DCF) that were housed for 21 days in glass tanks. Procambarus clarkii were dissected to determine the total hemocytes count and heavy metal concentrations in the hemolymph, abdominal muscles, and hepato-pancreas. The results showed that the depuration has led to a significant decrease in the total count of hemocytes, however, it increased the percentages of semi-granular cells, granulocytes and decreased the percentage of hyalinocytes. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed different protein patterns between FCF and DCF. Not all the selected heavy metals were detected in the collected water samples and in the investigated tissues. Depuration has led to a significant decrease of the heavy metals, if present, in the hemolymph, abdominal muscles, and hepato-pancreas. Collectively, the depuration resulted in significant decreases in the total hemocytes count and eliminated the selected heavy metals from the different tissues of P. clarkii.

Raw oysters are considered a culinary delicacy but are frequently the culprit in food-borne norovirus (NoV) infections. As commercial depuration procedures are currently unable to efficiently eliminate NoV from oysters, an optimisation of the process should be considered. This study addresses the ability of elevated water temperatures to enhance the elimination of NoV and Tulane virus (TuV) from Pacific oysters (Crassostrea gigas). Both viruses were experimentally bioaccumulated in oysters, which were thereafter depurated at 12 °C and 17 °C for 4 weeks. Infectious TuV and viral RNA were monitored weekly for 28 days by TCID50 and (PMAxx-) RT-qPCR, respectively. TuV RNA was more persistent than NoV and decreased by < 0.5 log10 after 14 days, while NoV reductions were already > 1.0 log10 at this time. For RT-qPCR there was no detectable benefit of elevated water temperatures or PMAxx for either virus (p > 0.05). TuV TCID50 decreased steadily, and reductions were significantly different between the two temperatures (p < 0.001). This was most evident on days 14 and 21 when reductions at 17 °C were 1.3–1.7 log10 higher than at 12 °C. After 3 weeks, reductions > 3.0 log10 were observed at 17 °C, while at 12 °C reductions did not exceed 1.9 log10. The length of depuration also had an influence on virus numbers. TuV reductions increased from < 1.0 log10 after seven days to > 4.0 log10 after 4 weeks. This implies that an extension of the depuration period to more than seven days, possibly in combination with elevated water temperatures, may be beneficial for the inactivation and removal of viral pathogens. [ABSTRACT FROM AUTHOR]

Microplastic contamination is a growing marine environmental issue with possible consequences for seafood safety. Filter feeders are the target species for microplastic (MPs) pollution because they filter large quantities of seawater to feed. In the present study, an experimental contamination of Mytilus galloprovincialis was conducted using a mixture of the main types of MPs usually present in the seawater column (53% filaments, 30% fragments, 3% granules) in order to test the purification process as a potential method for removing these contaminants from bivalves intended for human consumption. A set of molecular biomarkers was also evaluated in order to detect any variations in the expression levels of some genes associated with biotransformation and detoxification, DNA repair, cellular response, and the immune system. Our results demonstrate that: (a) the purification process can significantly reduce MP contamination in M. galloprovincialis; (b) a differential expression level has been observed between mussels tested and in particular most of the differences were found in the gills, thus defining it as the target organ for the use of these biomarkers. Therefore, this study further suggests the potential use of molecular biomarkers as an innovative method, encouraging their use in next-generation marine monitoring programs.

Anadara granosa are one of the benthic organisms that are frequently reported because contained heavy metals because of water pollution. This is because A. granosa is a feeder filter so that accumulates heavy metals in its body. Reduce the levels of heavy metals with activated charcoal from coconut shells in the absorbance process using the depuration method. It is re-optimized with the use of nano-active charcoal. The goal was to determine the effect of concentrations of nano-active charcoal from coconut shells on the heavy metal content of A. granosa. Stages of this reserch, namely charcoal activation, ultrasonication, SEM testing, blood shell depuration, and heavy metal testing. Based on the results of the Scanning Electron Microscope (SEM) Test it is known that the charcoal particles are sized 10-9 nm. The types of heavy metals found included hydrargyrum (Hg) 0.0009 mg/kg, cadmium (Cd) 0.62 mg/kg, and plumbum (Pb) 1.82 mg/kg. Heavy metals with lowest content is found in P5 (active charcoal concentration of 15% of the sample weight) of mercury (Hg) 0.0002 mg/kg; cadmium (Cd) 0.1 mg/kg; and lead (Pb) 0.373 mg/kg. This shows that the higher concentraion of activated charcoal given, the lower heavy metal content.

The Pacific oyster could be affected by several pressure sources during cold chain logistics, which reduce the quality of oyster, and even improve its mortality. For improving the quality of oyster, the effects of depuration process at different cooling rates (1, 3, 7, 11 and 16 °C/h) on selected Pacific oyster were studied. The results indicated that extreme fluctuations in the depuration temperatures could affect the survival rates and qualities of oysters. The oysters exhibited low survival rates, glycogen contents and pH values at an increased cooling rate. Their contents in the 1 °C/h group after 3 d preservation were 100 %, 16.30 ± 1.64 mg/100 g and 6.72 ± 0.01, respectively, while there were 71 %, 7.72 ± 0.88 mg/100 g and 6.53 ± 0.01 in the 16 °C/h group after 3 d preservation, respectively. Furthermore, the ATP-related compounds were affected by the different cooling rates. AMP and IMP were the main ATP-related compounds, and their contents in the 1 °C/h group after 3 d preservation were 37.21 ± 1.10 mg/100 g and 29.47 ± 1.10 mg/100 g, respectively, while there were 32.07 ± 1.10 mg/100 g and 13.16 ± 1.60 mg/100 g in the 16 °C/h group after 3 d preservation, respectively. The proportions of the total umami, as well as the sweet amino acids also decreased, the proportions of the umami amino acids and sweet amino acids in the total amino acids, were 31.37%–38.80%, and their proportions in 1 °C/h group were higher than that in 16 °C/h group. Conversely, the fatty acid content of each group exhibited significant differences. Combined with the above results, the oyster maintained a high survival rate and higher quality at a cooling rate of 1 °C/h during depuration.

The accumulation of marine biotoxins in shellfish and their consumption causes serious food safety problems, threatening human health and compromising the availability of protein-based food. It is thus urgent to develop methodologies for the detoxification of live bivalves, avoiding their economic and nutritional devaluation. In this context, we tested an adsorption mechanism of paralytic shellfish toxins (PST) based on a cation-exchange resin. The first studies using cultures of Gymnodinium catenatum (natural producers of PST) showed a decrease of about 80% in overall toxicity after 48 h. Interestingly, we found that the toxins are adsorbed differently, with toxins' structural features playing a part in the adsorption capacity via steric hindrance, electronic effects, or the extent of positive charge density (e.g., dcSTX). The positive effect of the resin in accelerating PST clearance from live mussels (Mytilus edulis) is not evident when compared to resin-free clearance; nevertheless, relevant information could be gathered that will facilitate further in vivo studies. Several factors appear to be at play, namely the competition of natural substances (e.g., salts, organic matter) for the same binding sites, the blocking of pores due to interactions between molecules, and/or difficulties in resin absorption by mussels. Additionally, the present work revealed the ability of mussels to neutralize pH and proposes bioconversion reactions among the PST molecules. [ABSTRACT FROM AUTHOR]

Land‐based Atlantic salmon, Salmo salar, grow‐out facilities utilize depuration to remediate off‐flavor. Water used in this process is either discharged or repurposed as supply water in recirculating aquaculture systems (RAS). Both approaches require an understanding of water quality and waste production for water treatment decisions and compliance with pollution discharge standards; however, these data were lacking. Therefore, a study was carried out to characterize these parameters. To begin, 311 salmon (5–6 kg) originally cultured in freshwater RAS were stocked at 100 kg/m3 in an 18 m3 depuration tank. Feed was withheld 1 day before transfer and throughout the 7‐day study period. Hours after stocking, total suspended solids (TSS), total phosphorus (TP), and total ammonia nitrogen (TAN) levels spiked, and concentrations declined thereafter. Delta TSS and TP were negligible by the end of the trial; however, TAN plateaued, indicating that salmon began to catabolize somatic tissue in the absence of feeding. Geosmin and 2‐methylisoboreol levels in water and fish were low throughout the study. This research indicates that residual waste production occurs while depurating Atlantic salmon. Procedural refinements and recommendations were gleaned including locality for introducing depuration system water within RAS and extension of the feed withholding period before depuration. [ABSTRACT FROM AUTHOR]

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Domoic acid (DA) is a potent neurotoxin produced by worldwide distributed diatoms of the genus Pseudo-nitzchia (PSN) and is responsible for Amnesic Shellfish Poisoning (ASP) in humans. King scallop Pecten maximus, a bivalve species of high commercial interest, is regularly subjected to blooms of Pseudo-nitzschia sp., thus accumulating and retaining high levels of DA for extended periods, leading to prolonged fisheries and aquaculture closures and important economic losses following increasingly recurrent toxic PSN blooms. The underlying mechanisms behind this accumulation and long toxin retention remain poorly understood so far. Fishermen and the aquaculture industry ask for methods to accelerate DA depuration in contaminated scallops, which has led to investigate the effect of some substances such as the antioxidant N-Acetylcysteine (NAC), which was previously found to improve up to four-fold DA depuration in P. maximus adductor muscle. Our study investigated the potential of NAC to accelerate DA depuration in all scallop tissues, including the digestive gland (DG), where most of the toxin is accumulated. Twenty-four contaminated adult scallops were collected following a toxic P. australis bloom in the Bay of Brest (France) and half were treated with the antioxidant NAC (250 mg L−1) for 6 days. HPLC toxin quantification analyses did not revealed any significant differences in the DA burdens in the DG between treated scallops and the control group. DA amounts in the adductor muscle and gonads were below the HPLC detection limit in both groups. Our results revealed that NAC does not thus appear as a commercially suitable solution for fisheries and aquaculture industries as DA depuration enhancer in the tested conditions. [ABSTRACT FROM AUTHOR]

Human norovirus (HuNoV) is a major foodborne pathogen that causes acute viral gastroenteritis, and bivalve shellfish are one of the main carriers of HuNoV transmission. A comprehensive understanding of bivalve shellfish-related HuNoV outbreaks focusing on contamination factors, bioaccumulation mechanisms, and pre- and post-harvest interventions is essential for the development of effective strategies to prevent contamination of shellfish. This review comprehensively surveys the current knowledge on global contamination and non-thermal treatment of HuNoV in bivalve shellfish. HuNoV contamination in bivalve shellfish is significantly related to the season and water. While evaluating the water quality of shellfish-inhabited waters is a key intervention, the development of non-heat treatment technology to effectively inactivate the HuNoV in bivalve shellfish while maintaining the flavor and nutrition of the shellfish is also an important direction for further research. Additionally, this review explores the bioaccumulation mechanisms of HuNoV in bivalve shellfish, especially the mechanism underlying the binding of histo-blood group antigen-like molecules and HuNoV. The detection methods for infectious HuNoV are also discussed. The establishment of effective methods to rapidly detect infectious HuNoV and development of biological components to inactivate or prevent HuNoV contamination in shellfish also need to be studied further. [ABSTRACT FROM AUTHOR]

ABSTRACT Anomalocardia brasiliana is an intertidal filter-feeding clam that can accumulate enterobacteria, such as Escherichia coli, and consequently affect human health. Shellfish depuration is a procedure which reduces microbiological contaminants; however, salinity and depuration time can vary across species to adequately reduce bacteria load. To analyze the effect of salinity on the bioaccumulation and depuration of E. coli by A. brasiliana, this study evaluated salinity and depuration time in animals artificially contaminated with E. coli. Each experimental group of clams were acclimated for 6 hours in a recirculating aquaculture system (RAS) and then exposed to E. coli for 18 hours. Following exposure, clams were then held at one of four salinities (35, 30, 25 e 20) for a period of one of four depuration times (0, 12, 24, 36 and 48h). The highest bioaccumulation of E. coli in A. brasiliana was observed in clams held at salinities of 35, 30 and 25. The greatest reduction of E. coli in A. brasiliana was observed in clams held at 25 for 48 hours. A salinity of 20 showed low bioaccumulation and depuration of E. coli. The results of this study will contribute to developing a protocol for depurating A. brasiliana to mitigate human health concerns.

• Fish guts can better reflect MPs pollutants both in fishes and aquatic environment. • The absence of food increased the ecological risk of fish in accumulating MPs. • Fish guts aggressively excrete MPs under severe microplastic contaminations. • Fish guts exhibited higher depuration rate with the presence of food resources. Microplastics (MPs, ＜5mm in size) have rapidly spread across aquatic ecosystems, which urgently needs systematic assessment for their ecological risk. Fish species have frequently been selected as indicator organisms in evaluating MPs contaminants. However, it has been questioned that which organs of fishes should be examined due to tissue-specific results. In this study, we investigated the accumulation and depuration process of MPs in the main organs of zebrafish under different MPs concentrations as well as the presence and absence of food resources. Our results recorded consistently higher MPs accumulation in fish guts among different MPs concentrations, implying fish guts as stable organs representing organisms' MPs contaminants. Meanwhile, MPs accumulated in fish guts increased significantly with increasing exposure concentrations, highlighting fish guts as sensitive organs in reflecting MPs contamination in aquatic environments. In addition, MPs accumulated in fish guts under non-feeding conditions followed a logistic "S" curve while fluctuated under feeding conditions, suggesting increased ecological MPs risk with the absence of food resources. The depuration rate in fish guts was significantly higher in the feeding group than in the non-feeding group, implying better expelling ability of MPs with the presence of food resources. Our study proposes fish guts as the optimal indicator organs in assessing the ecological risk of MPs contaminants in both fish bodies and aquatic environments, and highlights the importance of sustaining sufficient food resources in aquatic environments to reduce the MPs triggered adverse effects on fish species. [ABSTRACT FROM AUTHOR]

This study assesses and compares the efficiency of three commercial depuration systems for live bivalve mollusc production. Ruditapes philippinarum (Rp), Ruditapes decussatus (Rd), Donax trunculus (Dt), and Venus verrucosa (Vv) were used as research materials to evaluate full open (FO), semi-closed (SC), and closed cycle (CC) systems. Results reveal a logarithmic decrease in Escherichia coli levels during the initial six hours across all species. Rd achieved full depuration after 12 hours in the CC system and 24 hours in the FO system; Vv required 18 hours, while others needed up to 24 hours. At the 4600 MPN/100 g level, the CC system fortified by an ozone generator showed the most efficient depuration with the following results: 18 hours for Rp and Vv, 24 hours for Rd, and 36 hours for Dt. The SC system prolonged depuration times for all species. Species-specific filtration behaviour emerged as a crucial factor during contamination and depuration rates. Statistical analysis highlighted pH, dissolved oxygen, and salinity as key parameters influencing depuration efficiency, with temperature showing lesser significance compared to other variables for effective species-specific system design. This study focuses on identifying the parameters affecting the depuration characteristics of different bivalve species and commercial systems, and predicting the effects of potential changes. The findings are expected not only to enhance scientific understanding in this field but also to contribute to the system designs and adaptation of existing businesses to various conditions. [ABSTRACT FROM AUTHOR]

Microplastics are ubiquitous in the aquatic environment, and bivalves such as the Eastern oyster (Crassostrea virginica) can accumulate these particles directly from the water column. Bivalves are concurrently exposed to pathogenic and toxin-producing bacteria, including Vibrio spp. and Microcystis spp., which have been shown to adversely impact filtration rates. Exposure to these bacteria could thus affect oysters' ability to accumulate and depurate microplastics. As climate change creates conditions that favor Vibrio spp. and Microcystis spp. growth in estuaries, it is increasingly important to understand how these co-occurring biotic stressors influence microplastic contamination in bivalves. The objective of this study was to examine how co-exposures to Vibrio vulnificus and Microcystis aeruginosa influence microplastic accumulation and depuration in Eastern oysters. Oysters were exposed to nylon microplastics (5000 particles L−1) and either V. vulnificus, M. aeruginosa, or both species (104 colony-forming units or cells mL−1, respectively) and sampled over time up to 96 h. Following exposure, remaining oysters were allowed to depurate in clean seawater and sampled over time for up to 96 h. Microplastic concentrations in oysters were quantified and compared among treatments, and rate constants for uptake (k u) and depuration (k d) were calculated using nonlinear regression and two-compartment kinetic models. Overall, microplastic concentrations in oysters exposed to V. vulnificus (X ‾ = 2.885 ± 0.350 (SE) particles g−1 w.w.) and V. vulnificus with M. aeruginosa (X ‾ = 3.089 ± 0.481 particles g−1 w.w.) were higher than oysters exposed to M. aeruginosa (X ‾ = 1.540 ± 0.235 particles g−1 w.w.) and to microplastics alone (X ‾ = 1.599 ± 0.208 particles g−1 w.w.). Characterizing microplastic accumulation and depuration in oysters co-exposed to these biotic stressors is an important first step in understanding how contaminant loads in bivalves can change. With this research, the efficacy of depuration for commonly-consumed seafood species can be estimated. [Display omitted] • Microplastic concentrations were higher in oysters exposed to Vibrio vulnificus. • Patterns of microplastic depuration in oysters differed with bacterial exposure. • Following 96 h, oysters depurated between 44.6 and 61.5% of particles. • Rate constants for particle uptake and depuration with biotic stressors were estimated. [ABSTRACT FROM AUTHOR]

Direct ingestion of micro/nanoplastics (MNPs) results in significant accumulation in gastrointestinal (GI) tract of fish. The breathing process of fish makes MNPs easily retained in their gills. However, the uptake of MNPs in other fish organs remains largely unknown, let alone their kinetic processes. Herein, microplastics (MPs) and nanoplastics (NPs) in vivo imaging and precise quantification in various tissues (GI tract, gill, liver, brain, eye, and skin) of seawater (SW)- and freshwater (FW)- acclimated medaka Oryzias melastigma were achieved at an environmentally relevant concentration. Subsequently, the distribution kinetics of MNPs was investigated over a 96-h uptake and 48-h depuration period. MNPs were quickly and mostly captured in GI tract and gill of O. melastigma , and then transferred to liver and brain likely via blood circulation. Such transport was more efficient for NPs as compared to MPs, as evidenced by the consistently higher bioconcentration factors in both SW and FW conditions. The detection of MNPs in eye and skin of O. melastigma was more of an adsorption process, although the specific mechanisms of adsorption and absorption process can hardly be clearly differentiated. This study presented distribution kinetics of MNPs in O. melastigma and highlighted their possible transportation among tissues. [Display omitted] • NIR-AIE-MNPs probes were synthesized for in vivo imaging and tissue quantification. • Distribution kinetics of MNPs were studied in medaka from uptake to depuration. • MNPs were mostly located in GI tract and gill among all organs of medaka. • Higher MNPs BCFs in FW than SW was only observed in liver of medaka. • MNPs had high potential to adhere to eye and skin of medaka. [ABSTRACT FROM AUTHOR]

Marine toxins pose a significant safety risk, leading to human intoxications and causing substantial economic losses in seafood-producing regions. The development of rapid, cost-effective, efficient, and reliable approaches for the containment of these substances is therefore crucial in order to mitigate the adverse impact of marine toxins. This research conducted a comprehensive review on the toxicity and influencing factors of marine toxins production. Additionally, depuration technologies, including adsorption, advanced oxidation processes, biodegradation, heating treatment, temporary maintenance and purification, and drug inhibition, were systematically summarized. The study also provided a comparative analysis of the advantages and disadvantages of various depuration technologies and proposed strategies for future development. [Display omitted] • The toxicity, distribution and influencing factors of marine toxins were examined. • Depuration technologies, like AOPs, biodegradation, adsorption have been updated. • The cutting-edge materials and techniques were extensively discussed. • The advantages and disadvantages of different depuration methods were compared. [ABSTRACT FROM AUTHOR]

Two burrowing clam species, namely Meretrix meretrix and Paphia undulata , were offered two sizes (small: 45–53 μm, and large: 106–125 μm) of fluorescent red polyethylene microbeads, and the ingestion (number of MPs in the body tissue and faeces) and rejection (number of MPs in pseudofaeces) of MPs investigated. Overall, MP beads ingested were 36 % more than those rejected. There was also a significant interaction between the size and fate of MPs. For both species, significantly more small beads were ingested than rejected, but there was no difference for the large beads. P. undulata ingested more MPs than M. meretrix and both species could depurate all the ingested MPs in 72 h, although a longer time was needed for the former species. The results can provide guidance on seafood selection and pre-treatment to minimize the number of MPs ingested by humans. • MP beads being ingested were 36 % more than those being rejected. • P. undulata ingested significantly more MPs than M. meretrix. • Significant interaction occurred between the size and fate of MPs, with smaller beads tended to be ingested. • Both species could depurate all the ingested MPs in 72 h. • The clams collected from the wild or aquaculture farms are recommended to depurate in clean seawater for 1–2 days. [ABSTRACT FROM AUTHOR]

Benzo[ a ]pyrene (BaP), a representative five-membered polycyclic aromatic hydrocarbon, has been extensively studied as a pollutant for decades. Despite this, sex-specific responses to BaP exposure remain poorly understood. This study employed a life-cycle exposure approach to investigate the effects of prolonged BaP exposure on marine medaka (Oryzias melastigma), highlighting sex-specific responses. After a 90-day exposure period, significant variations in biometric measurements and oxidative stress markers were observed between male and female fish. BaP exposure resulted in weak detoxification defense in males, while females exhibited an opposite response. Transcriptomic analysis revealed 13 significantly enriched pathways in males and 11 in females, with varying numbers of differentially expressed genes between the sexes, highlighting distinct biological responses. Host resistance assay showed higher mortality rates among BaP-exposed males, and suppressed immune gene expressions and lysozyme activity, while females demonstrated enhanced immune genes and lysozyme activity post-challenge, indicating a more resilient defense response. Furthermore, after a one-month depuration period following BaP exposure, male medaka demonstrated slower recoverability compared to females. These findings underscore sex-specific effects of BaP exposure on fish, with females displaying stronger resilience. Understanding these distinctions are crucial for accurately assessing the impact of environmental pollutants on the aquatic population and ecosystem maintenance. [Display omitted] • Analysis of sex-specific responses to life-cycle BaP exposure. • Male and female medaka fish exhibited distinct responses. • Females demonstrated greater resilience towards BaP. • Recoverability was faster in females compared to males. • The male immune system was more compromised. [ABSTRACT FROM AUTHOR]