Multi-characteristic toxicity of enantioselective chiral fungicide tebuconazole to a model organism Mediterranean mussel Mytilus galloprovincialis Lamarck, 1819 (Bivalve: Mytilidae)

Personal care products as a potential source of aquatic pollution: Effect of polyvinyl alcohol on physiological and antioxidant responses in Mytilus galloprovincialis

A high percentage of the broad spectrum of contaminants in aquatic environments is represented by personal care products (PCPs). Polyvinyl alcohol (PVA) is contained in the formulation of many of these products. The extensive use of PVA caused the annual release of over 65.000 tons into the environment, constituting 1.2 % of particles in the Mediterranean Sea. For these reasons, the study aimed to investigate, for the first time in bivalve species, the possible cytotoxicity implications on non-target species, involved in the human food chain, caused by exposure to two different concentrations of PVA (PVA1: 0.1 mg L-1 and PVA2: 10 mg L-1). Following a fortnight of exposure, cell viability, regulation of cell volume decrease, oxidative stress, and biochemical parameters were evaluated. Moreover, the capability of the animal to produce byssal plaques was observed, representing a novelty for assessing the health status of mussels. The results showed a modification in the regulatory capacity of cell volume, particularly in those exposed to PVA2. An alteration in the superoxide dismutase activity (in PVA2) and in the levels of oxidatively modified proteins (PVA1 and PVA2) was detected in gills. A modification in the byssal plaque production following PVA exposure was also observed. These findings enrich the knowledge about the interaction between PVA and organisms, underscoring further research's need to elucidate the environmental implications.

Elevated trace element concentrations in Arabian scallops, Natal rock oysters, and Intermediate clams in the Persian Gulf

BACKGROUNDS

This study aimed to quantify trace element concentrations in Arabian scallops (Mimachlamys sanguinea), Natal rock oysters (Saccostrea cucullata), and Intermediate clams (Tivela damaoides). These elements accumulate over time from water, food, and sediment, potentially leading to toxicity.

MATERIALS AND METHODS

Specimens were collected from coastal waters around Larak Island, processed, and analyzed for trace elements including copper (Cu), iron (Fe), cadmium (Cd), lead (Pb), arsenic (As), mercury (Hg), zinc (Zn), vanadium (V), magnesium (Mg), manganese (Mn), selenium (Se), nickel (Ni), and cobalt (Co). The samples were ashed, digested, and then analyzed using inductively coupled plasma mass spectrometry (ICP-MS).

RESULTS

The findings revealed that Fe levels were highest in T. damaoides, significantly exceeding those in M. sanguinea (p < 0.05). Cd concentrations were significantly higher in M. sanguinea compared to S. cucullata and T. damaoides (p < 0.05). Zn, Mn, Ni, Pb, V, Co, Hg, Cu, As, and Se showed no significant interspecies differences (p > 0.05). However, significant variations were noted for Mg with T. damaoides showing the highest levels markedly more significant than those observed in M. sanguinea (p < 0.05). Comparison with WHO/FAO standards showed that Pb levels in the soft tissues of all three bivalve species exceeded permissible limits, though other metals were within safe consumption levels.

CONCLUSION

This study revealed that lead concentrations in the soft tissues of bivalves exceeded WHO/FAO safety limits, indicating a potential health risk. These findings emphasize the necessity of monitoring trace element contamination in bivalves to ensure seafood safety and protect public health.

Assessing the chronic toxicity of climbazole to Daphnia magna: Physiological, biochemical, molecular, and reproductive perspectives

The widespread use of climbazole (CBZ) has led to its increased presence in aquatic environments, potentially threatening freshwater ecosystems. However, evidence regarding the harmful effects of CBZ on aquatic organisms remains limited. In this study, Daphnia magna was exposed to CBZ at concentrations of 0, 0.2, 20, and 200 μg/L for 21 days to evaluate its chronic toxicity through assessment of life-history traits, physiological parameters, biochemical analyses, and gene expression. The results indicated that CBZ exposure delayed the days to the first brood, reduced the frequency of molting per adult, decreased the offspring number at first brood, diminished the body length, and decreased both the total number of broods per female and the total number of offspring per female. Additionally, CBZ inhibited the swimming speed, filtration rate, and ingestion rate. Moreover, CBZ altered the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH), while increasing malondialdehyde (MDA) levels. Gene expression analysis revealed varied responses in mRNA levels related to metabolic detoxification (cyp360a8, gst, and p-gp), digestive enzymes (α-amylase, α-esterase, and trypsin), energy (ak), oxygen transport (dhb), and reproduction (nvd, cyp314, ecr, vtg, and jhe) following CBZ exposure. These results indicate that the presence of CBZ in aquatic environments can induce toxicity by altering energy acquisition, supply, and metabolism; impairing metabolic detoxification pathways; eliciting oxidative stress; and causing reproductive toxicity in D. magna.

Appraisal of a synthetic preservative, Quaternium - 15, effect on three model organisms: new insight on environmental risks

After the COVID-19 pandemic, the use of quaternary ammonium compounds increased exponentially due to their efficacy as antimicrobials, stabilizers and disinfectants. Among these, Quaternium-15 is a preservative used in the formulation of a variety of personal care products. The increased use of this substance and the resulting persistence in wastewater treatment systems, which are unable to completely remove the Quaternium-15 from the water, is of increasing environmental concern. Using embryotoxicity analyses, this study aimed to investigate the effects of exposure to Quaternium-15 on non-target species and the resulting risks to the environment. Embryotoxicity endpoints such as mortality, hatching, presence of malformations, altered heartbeat and animal length were used to assess the effects on three model organisms (Cyprinus carpio, Danio rerio, Xenopus laevis) were evaluated during a 96-hour exposure to six different concentrations of Quaternium-15 (1, 5, 10, 15, 20 and 25 mg/L). The results obtained from the analyses highlighted: significant mortality for all three model organisms in the highest concentrations tested in which all the embryos died after 96 hpf, a delay in hatching of C. carpio and D. rerio compared to the control group, the insurgence of malformations in all the model organisms chosen and a significant decrease in heartbeat rate for the fish models. Each of these observations underlies the negative interaction between the Quaternium-15 and aquatic organisms making necessary further investigation to prevent damage to ecosystems and non-target species.

Microplastic ingestion in mussels from the East Mediterranean Sea: Exploring its impacts in nature and controlled conditions

Microplastic ingestion poses a significant concern for a plethora of marine organisms due to its widespread presence in marine ecosystems. Despite growing scientific interest, the effects on marine biota are not yet well understood. This study investigates the ingestion of microplastics (MPs) by mussels from various marine environments and assesses the associated effects that can be induced by MPs and associated toxic chemicals. Biomarkers of oxidative stress (catalase, lipid peroxidation), biotransformation (glutathione S-transferase), genotoxicity (micronuclei frequency) and neurotoxicity (acetylcholinesterase) were employed. Mussels, considered reliable bioindicators of MPs pollution, were sampled by hand from diverse locations under varied anthropogenic pressures, including a highly touristic Marine Protected Area (MPA) in the Ionian Sea, a mussel farm and a fish farm in the Aegean Sea. The results revealed the highest MP ingestion in mussels from the fish farm [0.21 ± 0.04 (SE) MPs/g or 0.63 ± 0.12 (SE) MPs/Ind.], likely due to plastic aquaculture equipment use. Stereoscopic observation revealed fibers, as the predominant shape of ingested MPs across all sites, and μFTIR polymer identification revealed the presence of various types, with polyethylene (PE) and polyamide (PA) being the most abundant. Significant physiological alterations in mussels related to MP ingestion levels were observed through biomarkers indicative of oxidative stress and biotransformation, as well as the Integrated Biomarker Response (IBR index). However, laboratory experiments with mussels exposed to controlled increasing PE concentrations for four weeks, did not show significant effects triggered by the PE ingestion, possibly indicating other environmental factors, such as contaminants from aquaculture environments, may influence biomarker levels in the field. Despite the observed effects, MP ingestion rates in mussels from the field were relatively low compared to other studies. Future research should continue to investigate the interactions between MPs and marine organisms in diverse environments to better understand and mitigate their impacts.

Mytilus galloprovincialis: A valuable bioindicator species for understanding the effects of diclofenac under warming conditions

Drugs are chemical compounds used to treat and improve organic dysfunctions caused by diseases. These include analgesics, antibiotics, antidepressants, and antineoplastics. They can enter aquatic environments through wastewater streams, where their physico-chemical properties allow metabolites to distribute and accumulate. Current climate change and associated extreme weather events may significantly impact these substances' toxicity and aquatic organisms' sensitivity. Among the chemicals present in aquatic environments is the non-steroidal anti-inflammatory drug diclofenac (DIC), which the EU monitors due to its concentration levels. This study investigated the influence of temperature (control at 17 °C vs. 21 °C) on the effects of DIC (0 μg/L vs. 1 μg/L) in the mussel species Mytilus galloprovincialis. Significant results were observed between 17 and 21 °C. Organisms exposed to the higher temperature showed a decrease in several parameters, including metabolic capacity and detoxification, particularly with prolonged exposure. However, in some parameters, after 21 days, the M. galloprovincialis showed no differences from the control, indicating adaptation to the stress. The results of this study confirm that DIC concentrations in the environment, particularly when combined with increased temperatures, can produce oxidative stress and adversely affect M. galloprovincialis biochemical and physiological performance. This study also validates this species as a bioindicator for assessing environmental contamination with DIC. Beyond its direct impact on aquatic organisms, the presence of pharmaceuticals like DIC in the environment highlights the interconnectedness of human, animal, and ecosystem health, underscoring the One Health approach to understanding and mitigating environmental pollution.

Transcriptomic analysis reveals interactive effects of polyvinyl chloride microplastics and cadmium on Mytilus galloprovincialis: Insights into non-coding RNA responses and environmental implications

Despite increasing concerns regarding the interactions of microplastic and heavy metal pollution, there is limited knowledge on the molecular responses of marine organisms to these stressors. In this study, we used whole-transcriptome sequencing to investigate the molecular responses of the ecologically and economically important bivalve Mytilus galloprovincialis to individual and combined exposures of environmentally relevant concentrations of PVC microplastics and cadmium (Cd). Our results revealed distinct transcriptional changes in M. galloprovincialis, with significant overlap in the differentially expressed genes between the individual and combined exposure groups. Genes involved in cellular senescence, oxidative stress, and galactose metabolism were differentially expressed. Additionally, key signaling pathways related to apoptosis and drug metabolism were significantly modulated. Notably, the interaction of PVC microplastics and Cd resulted in differential expression of genes involved in drug metabolism and longevity regulating compared to single exposures. This suggests that the interaction between these two stressors may have amplified effects on mussel health. Overall, this comprehensive transcriptomic analysis provides valuable insights into the adaptive and detrimental responses of M. galloprovincialis to PVC microplastics and Cd in the environment.

The effects of ACE inhibitor Enalapril on Mytilus galloprovincialis: Insights into morphological and functional responses

In the last decades, pharmaceuticals have emerged as a new class of environmental contaminants. Antihypertensives, including angiotensin-converting enzyme (ACE) inhibitors, are of special concern due to their increased consumption over the past years. However, the available data on their putative effects on the health of aquatic animals, as well as the possible interaction with biological systems are still poorly understood. This study analysed whether and to which extent the exposure to Enalapril, an ACE inhibitor commonly used for treating hypertension and heart failure, may induce morpho-functional alterations in the mussel Mytilus galloprovincialis, a sentinel organism of water pollution. By mainly focusing on the digestive gland (DG), a target tissue used for analysing the effects of xenobiotics in mussels, the effects of 10-days exposure to 0.6 ng/L (E1) and 600 ng/L (E2) of Enalapril were investigated in terms of cell viability and volume regulation, morphology, oxidative stress, and stress protein expression and localization. Results indicated that exposure to Enalapril compromised the capacity of DG cells from the E2 group to regulate volume by limiting the ability to return to the original volume after hypoosmotic stress. This occurred without significant effects on DG cell viability. Enalapril unaffected also haemocytes viability, although an increased infiltration of haemocytes was histologically observed in DG from both groups, suggestive of an immune response. No changes were observed in the two experimental groups on expression and tissue localization of heat shock proteins 70 (HSPs70) and HSP90, and on the levels of oxidative biomarkers. Our results showed that, in M. galloprovincialis the exposure to Enalapril did not influence the oxidative status, as well as the expression and localization of stress-related proteins, while it activated an immune response and compromised the cell ability to face osmotic changes, with potential consequences on animal performance.

Toxic effects of commercial grade indoxacarb and endosulfan on Gammarus kischineffensis (Schellenberg, 1937) (Crustacea: Amphipoda)

This study was designed to investigate the toxic effects of two frequently used commercial insecticides containing endosulfan and indoxacarb on a freshwater amphipod Gammarus kischineffensis. In this context, the 24, 48, 72 and 96 h LC50 values of these pesticides were determined for G. kischineffensis. Then the histopathological effects of these pesticides on the gill tissues of this species were evaluated. At the end of the study, the 96 h LC50 values of commercial-grade endosulfan and indoxacarb for G. kischineffensis were determined as 1.861 μg L-1 and 20.212 mg L-1, respectively. Histopathologically, the most common histopathological alterations in individuals exposed to sublethal concentrations of commercial-grade endosulfan and indoxacarb were pillar cell hypertrophy resulting in atrophy of the hemocoelic space and hemocytic infiltration. Considering these results, it can be said that commercial-grade endosulfan is extremely and indoxacarb is slightly toxic to G. kischineffensis.

The odd couple: Caffeine and microplastics. Morphological and physiological changes in Mytilus galloprovincialis

In recent years, the presence of pharmaceuticals and microplastics (MPs) in aquatic ecosystems has raised concerns about their environmental impact. This study explores the combined effects of caffeine, a common pharmaceutical pollutant, and MPs on the marine mussel Mytilus galloprovincialis. Caffeine, at concentrations of 20.0 μg L-1, and MPs (1 mg L-1, 35-50 μm size range), was used to mimic real-world exposure scenarios. Two hundred M. galloprovincialis specimens were divided into four groups: caffeine, MPs, Mix (caffeine + MPs), and Control. After a two-week acclimation period, the mollusks were subjected to these pollutants in oxygen-aerated aquariums under controlled conditions for 14 days. Histopathological assessments were performed to evaluate gill morphology. Cellular volume regulation and digestive gland cell viability were also analyzed. Exposure to caffeine and MPs induced significant morphological changes in M. galloprovincialis gills, including cilia loss, ciliary disk damage, and cellular alterations. The chitinous rod supporting filaments also suffered damage, potentially due to MP interactions, leading to hemocyte infiltration and filament integrity compromise. Hemocytic aggregation suggested an inflammatory response to caffeine. In addition, viability assessments of digestive gland cells revealed potential damage to cell membranes and function, with impaired cell volume regulation, particularly in the Mix group, raising concerns about nutrient metabolism disruption and organ function compromise. These findings underscore the vulnerability of M. galloprovincialis to environmental pollutants and emphasize the need for monitoring and mitigation efforts. RESEARCH HIGHLIGHTS: The synergy of caffeine and microplastics (MPs) in aquatic ecosystems warrants investigation. MPs and caffeine could affect gill morphology of Mytilus galloprovincialis. Caffeine-exposed cells had lower viability than the control group in the NR retention test. MPs and mix-exposed cells struggled to recover their volume.

The cerium oxide nanoparticles toxicity induced physiological, histological and biochemical alterations in freshwater mussels, Unio crassus

INTRODUCTION

Releasing of cerium oxide nanoparticles (nano-CeO2) to the nature has increased due to the widespread use in many fields ranging from cosmetics to the food industry. Therefore, nano-CeO2 has been included in the Organization for Economic Co-operation and Development's (OECD) priority list for engineering nanomaterials. In this study, the effects of nano-CeO2 on the freshwater mussels were investigated to reveal the impact on the freshwater systems on model organism.

METHODS

First, the chemical and structural properties of nano-CeO2 were characterized in details. Second, the freshwater mussels were exposed to environmentally relevant concentrations of nano-CeO2 as 10 mg, 25 mg and 50 mg/L during 48-h and 7-d. Third, after the exposure periods, hemolymph and tissue samples were taken to analyse the Total Hemocyte Counts (THCs) histology and oxidative stress parameters (total antioxidant status, glutathione, glutathione-S-transferase, and advanced oxidative protein products).

RESULTS

Significant decrease of the THCs was observed in the nano-CeO2 exposed mussels compared to the control group (P < 0.05). The histological results showed a positive association between nano-CeO2 exposure concentration in the water and level of tissue damage and histopathological alterations were detected in the gill and the digestive gland tissues. Oxidative stress parameters were slightly affected after exposure to nano-CeO2 (P > 0.05). In conclusion, this study showed that acute exposure of freshwater mussels to nano-CeO2 did not pose significant biological risk. However, it has been proven that mussels are able to accumulate nano-CeO2 significantly in their bodies.

CONCLUSION

This suggests that nano-CeO2 may be a potential risk to other organisms in the ecosystem through trophic transfer in the food-web based on their habitat and niche in the ecosystem.

Interactive effects of elevated temperature and Photobacterium swingsii infection on the survival and immune response of marine mussels (Perna canaliculus): A summer mortality scenario

The New Zealand Greenshell™ mussel (Perna canaliculus) is an economically important aquaculture species. Prolonged increases in seawater temperature above mussel thermotolerance ranges pose a significant threat to mussel survival and health, potentially increasing susceptibility to bacterial infections. Using challenge experiments, this study examined the combined effects of increased seawater temperature and bacterial (Photobacterium swingsii) infection on animal survival, haemocyte and biochemical responses of adult mussels. Mussels maintained at three temperatures (16, 20 and 24 °C) for seven days were either not injected (control), injected with sterile marine broth (injection control) or P. swingsii (challenged with medium and high doses) and monitored daily for five days. Haemolymph and tissue samples were collected at 24, 48, 72, 96, 120 h post-challenge and analysed to quantify bacterial colonies, haemocyte responses and biochemical responses. Mussels infected with P. swingsii exhibited mortalities at 20 and 24 °C, likely due to a compromised immune system, but no mortalities were observed when temperature was the only stressor. Bacterial colony counts in haemolymph decreased over time, suggesting bacterial clearance followed by the activation of immune signalling pathways. Total haemocyte counts and viability data supports haemocyte defence functions being stimulated in the presence of high pathogen loads at 24 °C. In the gill tissue, oxidative stress responses, measured as total antioxidant capacity and malondialdehyde (MDA) levels, were higher in infected mussels (compared to the controls) after 24h and 120h post-challenge at the lowest (16 °C) and highest temperatures (24 °C), indicating the presence of oxidative stress due to temperature and pathogen stressors. Overall, this work confirms that Photobacterium swingsii is pathogenic to P. canaliculus and indicates that mussels may be more vulnerable to bacterial pathogens under conditions of elevated temperature, such as those predicted under future climate change scenarios.

Evaluating quaternium-15 effects on Mytilus galloprovincialis: New insights on physiological and cellular responses

Among personal care products, quaternium-15 is prominently featured as a preservative in items such as shampoos, soaps, shaving products, and cosmetics. The widespread use of these products in people's daily routines contributes to quaternium-15 release into aquatic ecosystems. In this context, the primary aim of the study was to assess the physiological and cellular responses of the digestive gland and gills in Mytilus galloprovincialis to quaternium-15 exposure. Cell viability and the ability of digestive gland cells to regulate their volume were evaluated. Additionally, the expression of the genes involved in oxidative stress response was assessed to further substantiate the compound's harmful effects. Results indicated a significant decrease in both the viability of digestive gland cells and their RVD (regulatory volume decrease) capacity when exposed to a hypotonic solution. Furthermore, impairment of digestive gland cell function was corroborated by the modulation of oxidative stress-related gene expression, including SOD, Cat, as well as Hsp70 and CYP4Y1. Similar gene expression alterations were observed in the gills, reflecting impaired functionality in this vital organ as well. In summary, the outcomes of the study provide conclusive evidence of the toxicity of quaternium-15. This underscores the urgent need to further investigate the toxicological effects of this contaminant on aquatic ecosystems and emphasises the necessity of limiting the use of products containing quaternium-15.

Quantification of Photobacterium swingsii and characterisation of disease progression in the New Zealand Greenshell™ mussel, Perna canaliculus

Greenshell™ mussels (Perna canaliculus) are endemic to New Zealand and support the largest aquaculture industry in the country. Photobacterium swingsii was isolated and identified from moribund P. canaliculus mussels following a mass mortality event. In this study, a challenge experiment was used to characterise, detect, and quantify P. swingsii in adult P. canaliculus following pathogen exposure via injection into the adductor muscle. A positive control (heat-killed P. swingsii injection) was included to account for the effects of injection and inactive bacterial exposure. Survival of control and infected mussels remained 100% during 72-hour monitoring period. Haemolymph was sampled for bacterial colony counts and haemocyte flow cytometry analyses; histology sections were obtained and processed for histopathological assessments; and adductor muscle, gill, digestive gland were sampled for quantitative polymerase chain reaction (PCR) analyses, all conducted at 12, 24, 48 h post-challenge (hpc). The most profound effects of bacterial injection on mussels were seen at 48 hpc, where mussel mortality, haemocyte counts and haemolymph bacterial colony forming were the highest. The quantification of P. swingsii via qPCR showed highest levels of bacterial DNA at 12 hpc in the adductor muscle, gill, and digestive gland. Histopathological observations suggested a non-specific inflammatory response in all mussels associated with a general stress response. This study highlights the physiological effects of P. swingsii infection in P. canaliculus mussels and provides histopathological insight into the tissue injury caused by the action of injection into the adductor muscle. The multi-technique methods used in this study can be applied for use in early surveillance programs of bacterial infection on mussel farms.

Effects of nano-TiO2 and pentachlorophenol on the bioenergetics of mussels under predatory stress

Organic and nanoparticle pollutants are the main environmental problems affecting marine species, which have received great attention. However, the combined effect of pollutants on marine life in the presence of predators needs to be clarified. In this study, the effects of pentachlorophenol (PCP) and titanium dioxide nanoparticles (nano-TiO2) on the energy metabolism of mussels (Mytilus coruscus) in the presence of predators were assessed through cellular energy allocation (CEA) approach. Mussels were exposed to PCP (0, 1, and 10 μg/L), nano-TiO2 (1 mg/L, 25 and 100 nm), and predators (Portunus trituberculatus presence/absence) for 14 days. Exposure to high concentrations of PCP (10 μg/L) with small particle size nano-TiO2 (25 nm) decreased cellular energy stores (carbohydrates, lipids, and proteins) and increased cellular energy demand (measured as the activity of the mitochondrial electron transport system, ETS). During the first 7 days, energy was supplied mainly through the consumption of carbohydrates, while lipids are mobilized to participate after 7 days. The presence of predators caused a further decrease in energy stores. These findings demonstrate that PCP, nano-TiO2 and predators have a negative impact on energy metabolism at the cellular level. Carbohydrates are not able to meet the metabolic demand, lipids need to be consumed, and energy metabolism was also mediated by the involvement of proteins. Overall, our results suggest that PCP, nano-TiO2 and predators disrupt the cellular energy metabolism of mussels through reduced cellular energy allocation, small particles and predators drive mussels to exert energetic metabolic adjustments for detoxification reactions when toxic contaminants are present.

Chlorpromazine's impact on Mytilus galloprovincialis: a multi-faceted investigation

The antipsychotic chlorpromazine (Cpz) has raised concern as a pharmaceutical effluent due to its wide medical applications. Moreover, its potent pro-oxidant properties and impact on the cell viability of the marine mollusc Mytilus galloprovincialis, even at low concentrations (ng/L), have been noted. Based on this evidence, in this study, we investigated the physiological effects of Cpz on M. galloprovincialis, to elucidate its fate within the organism, in terms of bioaccumulation, biotransformation, byssus changes and stress responses of the cellular thiolome. Histological and indicators of vitality analyses were also performed to better evaluate the influence of the drug on the morphology and cell viability of the digestive gland. To this end, two different concentrations of Cpz (Cpz I (12 ng/L or 37 pM) and Cpz II (12 μg/L or 37 nM)) were administered to mussels over 14 days. Cpz accumulation in the digestive gland significantly increased with water concentration (BCF of Cpz I and Cpz II). Biochemical analyses indicated lysosomal dysfunction, reflected in elevated total Cathepsin D activity and compromised lysosomal membrane stability. Stress-related and metal-buffering proteins (GST and metallothionein) responded to both Cpz concentrations. Cpz I induced phase I biotransformation activity (CYP450-dependent EROD), while Cpz II triggered caspase-3 activation, indicative of detoxification overload. Histological analysis revealed digestive gland atrophy, epithelial thinning, haemocyte infiltration, and brown cell presence. Byssus analysis showed significant alterations. In conclusion, our study underscores Cpz-induced physiological and histological changes in M. galloprovincialis, posing potential implications for mussel health and confirming the utilisation of this mussel as an indication of Cpz ecotoxicity.

Effects of environmental hypoxia on the goldfish skeletal muscle: Focus on oxidative status and mitochondrial dynamics

The skeletal muscle is a highly plastic tissue. Its ability to respond to external stimuli and challenges allows it to face the functional needs of the organism. In the goldfish Carassius auratus, a model of hypoxia resistance, exposure to reduced oxygen is accompanied by an improvement of the swimming performance, relying on a sustained contractile behavior of the skeletal muscle. At the moment, limited information is available on the mechanisms underlying these responses. We here evaluated the effects of short- (4 days) and long- (20 days) term exposure to moderate water hypoxia on the goldfish white skeletal muscle, focusing on oxidative status and mitochondrial dynamics. No differences in lipid peroxidation, measured as 2-thiobarbituric acid-reacting substances (TBARS), and oxidatively modified proteins (OMP) were detected in animals exposed to hypoxia with respect to their normoxic counterparts. Exposure to short-term hypoxia was characterized by an enhanced SOD activity and expression, paralleled by increased levels of Nrf2, a regulator of the antioxidant cell response, and HSP70, a chaperone also acting as a redox sensor. The expression of markers of mitochondrial biogenesis (TFAM) and abundance (VDAC) and of the mtDNA/nDNA ratio was similar under normoxia and under both short- and long-term hypoxia, thus excluding a rearrangement of the mitochondrial apparatus. Only an increase of PGC1α (a transcription factor involved in mitochondrial dynamics) was detected after 20 days of hypoxia. Our results revealed novel aspects of the molecular mechanisms that in the goldfish skeletal muscle may sustain the response to hypoxia, thus contributing to adequate tissue function to organism requirements.

Dietborne Toxicity of Tebuconazole to a Benthic Crustacean, Heterocypris incongruens and Its Relative Contribution to the Overall Effects under Food-Water Equilibrium Partitioning

Tebuconazole (TEB), a widely used and persistent pesticide, has garnered attention due to its frequent detection in sediments worldwide. This widespread occurrence has raised concerns about potential dietborne toxicity to benthic crustaceans, as they may ingest contaminated particles in their habitat. While bioaccumulation studies indicate the importance of TEB ingestion for benthic crustaceans, limited data exist on direct dietborne toxicity testing. This study investigated the diet-related toxicity of TEB by subjecting a benthic ostracod, Heterocypris incongruens, to a 6 day toxicity test under dietary and combined exposures. Subsequently, the importance of dietary exposure for TEB toxicity was uncovered, followed by quantification of relative dietborne toxicity contributions using a modified concentration-additive model. Results revealed that the dietary route was more toxicologically significant than the aqueous route in equilibrium. The dietborne lethal concentration (LC50) for TEB on H. incongruens was 200 (170-250) mg/kg, with an 80% relative dietborne toxicity contribution. To gain comprehensive insights into dietborne significance, toxicity data were collected from previous studies involving different pollutants to calculate relative contributions. Finally, the correlation between dietborne toxicity and the partitioning coefficient was analyzed to understand the pollutant behavior and its toxic impact when ingested through the diet.

A comprehensive review on toxicological mechanisms and transformation products of tebuconazole: Insights on pesticide management

Tebuconazole has been widely applied over three decades because of its high efficiency, low toxicity, and broad spectrum, and it is still one of the most popular fungicides worldwide. Tebuconazole residues have been frequently detected in environmental samples and food, posing potential hazards for humans. Understanding the toxicity of pesticides is crucial to ensuring human and ecosystem health, but the toxic mechanisms and toxicity of tebuconazole are still unclear. Moreover, pesticides could transform into transformation products (TPs) that may be more persistent and toxic than their parents. Herein, the toxicities of tebuconazole to humans, mammals, aquatic organisms, soil animals, amphibians, soil microorganisms, birds, honeybees, and plants were summarized, and its TPs were reviewed. In addition, the toxicity of tebuconazole TPs to aquatic organisms and mammals was predicted. Tebuconazole posed potential developmental toxicity, genotoxicity, reproductive toxicity, mutagenicity, hepatotoxicity, neurotoxicity, cardiotoxicity, and nephrotoxicity, which were induced via reactive oxygen species-mediated apoptosis, metabolism and hormone perturbation, DNA damage, and transcriptional abnormalities. In addition, tebuconazole exhibited apparent endocrine-disrupting effects by modulating hormone levels and gene transcription. The toxicity of some TPs was equivalent to and higher than tebuconazole. Therefore, further investigation is necessary into the toxicological mechanisms of tebuconazole and the combined toxicity of a mixture of tebuconazole and its TPs.

Effects of acute exposure to environmentally realistic tebuconazole concentrations on stress responses of kidney and digestive gland of Lymnaea stagnalis

This study aimed to investigate the effects of 24 and 72 h exposure to environmentally relevant concentrations of tebuconazole (TEB) (10, 100 and 500 µg/L) fungicide on the freshwater snail Lymnaea stagnalis. The focus was induction of oxidative stress, alteration of gene expressions and histopathological changes in the kidney and digestive gland. TEB treatment induced a time- and concentration-dependent increase in intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) levels, while the total antioxidant capacity (TAC) was decreased. The activities of glutathione peroxidase (GPx), glutathione reductase (GR), and catalase (CAT) also increased in a time- and concentration-dependent manner in both tissues. TEB exposure significantly increased the mRNA levels of CAT, GPx, GR, heat shock proteins HSP40 and HSP70. Histological analysis revealed nephrocyte degeneration and disrupted digestive cells. The study concludes that acute exposure to TEB induces oxidative stress, alters antioxidant defense mechanisms, and leads to histopathological changes in L. stagnalis.

The toxicity effects of the individual and combined exposure of methyl tert-butyl ether (MTBE) and tire rubber powder (RP) on Nile tilapia fish (Oreochromis niloticus)

Methyl tert-butyl ether (MTBE) is soluble in water and can contaminate water sources when it spills during transportation or leaks from underground storage tanks. Incomplete combustion releases MTBE as exhaust fumes that can be deposited on urban surfaces. Meanwhile, car tires erosion emits of large amounts of rubber dust (RP), easily transported to water bodies. Therefore, this study has the objective of assessing the toxicity of varying concentrations of MTBE (0, 2.5, 5.0 μL L-1) and RP (0, 5.0, 10.0 mg L-1 RP), both individually and in combination, over a period of 28 days on Nile tilapia (Oreochromis niloticus). MTBE and PR decreased fish growth performance. Blood biochemical analytes indicated that MTBE and RP led to increasing Aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and creatinine phosphokinase (CPK), alkaline phosphatase and gamma-glutamyl transferase (GGT) activities. Alterations related to glucose, triglycerides, cholesterol, and creatinine, plasma contents, were also observed. Increased antioxidant biomarkers, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), glutathione reductase (GR), and malondialdehyde (MDA), was observed. Exposure fish to MTBE and PR changed metabolic profile of muscle tissue. Moreover, results showed that MTBE, its metabolites, and PR could accumulate in the muscle tissue of fish. Results suggest that MTBE and RP can impact fish health, both individually and when combined. The presence of MTBE enhances the toxicity of RP, indicating a synergistic effect. Nevertheless, further studies are needed to understand the impact of toxic compounds on aquatic environments and organisms' health.

Enantioselective effects of chiral prothioconazole and its metabolites: Oxidative stress in HepG2 cells and lysozyme activity

Chiral pesticides may exhibit enantioselectivity in terms of bioconcentration, environmental fate, and reproductive toxicity. Here, chiral prothioconazole and its metabolites were selected to thoroughly investigate their enantioselective toxicity and mechanisms at the molecular and cellular levels. Multispectral techniques revealed that the interaction between chiral PTC/PTCD and lysozyme resulted in the formation of a complex, leading to a change in the conformation of lysozyme. Meanwhile, the effect of different conformations of PTC/PTCD on the conformation of lysozyme differed, and its metabolites were able to exert a greater effect on lysozyme compared to prothioconazole. Moreover, the S-configuration of PTCD interacted most strongly with lysozyme. This conclusion was further verified by DFT calculations and molecular docking as well. Furthermore, the oxidative stress indicators within HepG2 cells were also affected by chiral prothioconazole and its metabolites. Specifically, S-PTCD induced more substantial perturbation of the normal oxidative stress processes in HepG2 cells, and the magnitude of the perturbation varied significantly among different configurations (P > 0.05). Overall, chiral prothioconazole and its metabolites exhibit enantioselective effects on lysozyme conformation and oxidative stress processes in HepG2 cells. This work provides a scientific basis for a more comprehensive risk assessment of the environmental behaviors and effects caused by chiral pesticides, as well as for the screening of highly efficient and less biotoxic enantiomeric monomers.

Enantiomer-specific burden of metalaxyl and myclobutanil in non-occupationally exposed population with evidence from dietary intake and urinary excretion

Metalaxyl (MET) and myclobutanil (MYC) are two widely used chiral fungicides that may pose health risks to non-occupationally exposed populations. Here, the two fungicides were enantiomer-specific quantified in the dietary food and urine of residents in an Eastern China city, to determine the exposure and excretion of these contaminants in different populations. Results indicate that residues of MET and MYC varied with different food items at 0.42-0.86 ng/g fresh weight (FW) and 0.18-0.33 ng/g FW, respectively. In urine samples, the residual levels after creatinine adjusting (CR) ranged from 10.2 to 1715.4 ng/g CR for MET and were below the detection limit up to 320.7 ng/g CR for MYC. Significant age- and gender-related differences were separately found in urinary MET and MYC of different populations. Monte-Carlo simulations suggested that children had higher daily dietary intake (DDI) but lower urinary excretion (DUE) rates than youths, and thus may suffer higher body burdens. The residues of antifungally ineffective enantiomers (S-MET and R-MYC) were slightly higher than their antipodes in foods. Moreover, the enantiomer-selective urinary excretion resulted in higher retention of S-MET and R-MYC in the human body. Our results suggest that both dietary intake and urinary excretion should be enantiomer-specifically considered when assessing the exposure risk and body burden of chiral fungicides in the non-occupationally exposed population. Furthermore, substitutive application of enantiomer-enriched fungicide formulations can not only benefit the antifungal efficacy but also be safer for human health.

Exploring the combined interplays: Effects of cypermethrin and microplastic exposure on the survival and antioxidant physiology of Astacus leptodactylus

Plastic waste and micro/nanoplastic particles pose a significant global environmental challenge, along with concerns surrounding certain pesticides' impact on aquatic organisms. This study investigated the effects of microplastic particles (MPPs) and cypermethrin (CYP) on crayfish, focusing on biochemical indices, lipid peroxidation, oxidative stress, hematological changes, and histopathological damage. After determining the LC50-96 h value (4.162 μg/L), crayfish were exposed to sub-lethal concentrations of CYP (1.00 ppb (20%) and 2.00 ppb (50%)) and fed a diet containing 100 mg/kg MPPs for 60 days. Hemolymph transfusion and histopathological examinations of the hepatopancreas were conducted. The results showed significant alterations in crayfish. Total protein levels decreased, indicating protein breakdown to counteract contaminants, while total cholesterol and triglyceride levels declined, suggesting impaired metabolism. Glucose levels increased in response to chemical stress. The decline in total antioxidant capacity highlighted the impact of prolonged xenobiotic exposure and oxidative stress, while increased CAT, SOD, and MDA activities helped mitigate oxidative stress and maintain cellular homeostasis. The elevated total hemocyte count, particularly in semi-granular cells, suggests their active involvement in the detoxification process. Further research is needed to fully understand the implications of these effects.

Effects of virgin and BaP-adsorbed microplastics ingestion by Manila clams (Ruditapes philippinarum)

Numerous microplastic-related studies have investigated the impact of plastic materials on the marine food chain. In this study, Manila clams were exposed to microplastic (MP) of various polymer types, shapes, and concentrations to determine the ingestion selectivity and adverse effects caused. Benzo[a]pyrene was introduced as the second stressor to investigate the role of MP as a vector of contaminant. The result of a 2-day acute exposure showed that clams are more likely to ingest those in sphere shapes due to their similarity to microalgae. The feeding rate continuously declined when clams were exposed to at least 2to/L particles. Additionally, co-exposure of MP and B[a]P resulted in higher DNA fragmentation but lower catalase activity compared to single exposure to MP. Our study revealed that the uptake of MP by clams is not only determined by its shape and concentration but also by the presence of existing contaminants.

Cellular and oxidative stress responses of Mytilus galloprovincialis to chlorpromazine: implications of an antipsychotic drug exposure study

Introduction: Bivalve molluscs like Mytilus galloprovincialis are valuable bioindicators due to their filter-feeding lifestyle, wide distribution, and ability to concentrate xenobiotics. Studying the effects of pharmaceuticals on these molluscs is crucial given their presence in surface waters. This study investigated the response of M. galloprovincialis to chlorpromazine (Cpz), an antipsychotic with antiviral activity against influenza, HIV, and coronaviruses in human cells. Methods: In this study, we examined the 14-day impact of chlorpromazine (Cpz) on the model species M. galloprovincialis at two concentrations (Cpz 1: 12 ng L-1 or 37 pM; Cpz 2: 12 µg L-1 or 37 nM). To ensure controlled exposure, a stock solution of Cpz was prepared and introduced into the tanks to match the intended concentrations. Seawater and stock solutions were refreshed every 48 h. The primary focus of this study centered on evaluating cell viability, cell volume regulation, and oxidative stress indicators. Results: Although cell volume regulation, as assessed by decreasing regulatory volume Regulation volume decrease, did not show statistically significant changes during the experiment, digestive cell viability, on the other hand, showed a significant decrease (p < 0.01) in the Cpz 2 group, suggesting effects on the general health and survival of these cells. Biochemically, in both Cpz 1 and Cpz 2, superoxide dismutase activity increased, while catalase (CAT) decreased, causing an elevated lipid peroxidation thiobarbituric acid-reactive substances and protein carbonyls, particularly in the Cpz 2 group. The level of reduced glutathione (GSH) increased in both exposures, whereas the level of GSSG increased only in the Cpz 1 group. Consequently, the GSH/GSSG ratio was elevated in the Cpz 2 group only. Discussion: A comparison of the magnitudes of anti- and pro-oxidative manifestations indicated a pro-oxidative shift in both exposures. These findings show that Cpz induces non-specific symptoms of biochemical and cellular disturbances in M. galloprovincialis even at the low picomolar concentration.

Anodonta cygnea, a freshwater swan mussel, exposed to diazinon: toxicity thresholds in behaviour and physiology

Swan mussels (Anodonta cygnea) have been suggested as suitable bioindicators for the presence of pollutants in the environment. Application of the physiological and behavioral markers in these sessile species can be beneficial for environmental monitoring. The present study aimed to investigate the relationship between the behavioral disorders of movement and siphoning associated with the inhibition of tissue Acetylcholinesterase (AChE). For experiments, overally 120 bivalves of Anodonta cygnea (mean total length 80.33 ± 6.7 mm) were transported from the agricultural drains and canals in Sari county (Mazandaran Province, Iran) to our laboratory. First, the LC50-96 h of diazinon was estimated according to the Organization for Economic Co-operation and Development (OECD 1992) guideline with static water conditions. The sub-lethal toxicity pesticide experiments were conducted on the basis of the lowest observed effect concentration (LOEC) and the maximum acceptable toxicant concentration (MATC). The LC50-96 h, LOEC, and MATC values of diazinon were 85.2, 42.1, and 8.5 mg L- 1, respectively. Based on the observations of mussels' movement, the burrowing and displacement decreased with the concentration of toxicant in water. Moreover, the presence of diazinon in water and its exposure to experimental animals significantly reduces their siphoning rate. The RDA showed that the AChE activity had a higher correlation with the siphoning behavior than the movement behavior. The comparison of enzyme activity at different exposure and recovery times showed that there was a significant difference among the groups affected by the consumed pesticide (p = 0.001, between contrasts). The most remarkable morphometric characteristic was the siphon opening that was inversely correlated with the enzymatic activity. Studies in bioethics might benefit from paying attention to these traits that are directly related to the level of toxicity and behavioral adaptations required for animal survival.

Internal Defense System of Mytilus galloprovincialis (Lamarck, 1819): Ecological Role of Hemocytes as Biomarkers for Thiacloprid and Benzo[a]Pyrene Pollution

The introduction of pollutants, such as thiacloprid and benzo[a]pyrene (B[a]P), into the waters of urbanized coastal and estuarine areas through fossil fuel spills, domestic and industrial waste discharges, atmospheric inputs, and continental runoff poses a major threat to the fauna and flora of the aquatic environment and can have a significant impact on the internal defense system of invertebrates such as mussels. Using monoclonal and polyclonal anti-Toll-like receptor 2 (TLR2) and anti-inducible nitric oxide synthetase (iNOS) antibodies for the first time, this work aims to examine hemocytes in the mantle and gills of M. galloprovincialis as biomarkers of thiacloprid and B[a]P pollution and analyze their potential synergistic effect. To pursue this objective, samples were exposed to the pollutants, both individually and simultaneously. Subsequently, oxidative stress biomarkers were evaluated by enzymatic analysis, while tissue changes and the number of hemocytes in the different contaminated groups were assessed via histomorphological and immunohistochemical analyses. Our findings revealed that in comparison to a single exposure, the two pollutants together significantly elevated oxidative stress. Moreover, our data may potentially enhance knowledge on how TLR2 and iNOS work as part of the internal defense system of bivalves. This would help in creating new technologies and strategies, such as biosensors, that are more suitable for managing water pollution, and garnering new details on the condition of the marine ecosystem.

Phthalates and their effects on human health: Focus on erythrocytes and the reproductive system

Plastics, long-chain artificial polymers, are used worldwide with a global production of 350 million tonnes per year. Various degradation processes transform plastics into smaller fragments divided into micro, meso and macroplastics. In various industries, such as construction, certain plastic additives are used to improve flexibility and enhance performance. Plastic additives include phthalates (PAE), dibutyl phthalate (DPB) and diethyl phthalate (DEP). Due to the use of plastics and plastic additives, these small fragments of different shapes and colours are present in all environmental compartments. For their characteristics, PAEs can be introduced particularly by ingestion, inhalation and dermal absorption. They can accumulate in the human body, where they have already been identified in blood, amniotic fluid and urine. The purpose of this review is to gather the effects that these plastic additives have on various systems in the human body. Being endocrine disruptors, the effects they have on erythrocytes and how they can be considered targets for xenobiotics have been analysed. The influence on the reproductive system was also examined. Phthalates are therefore often overused. Due to their properties, they can reach human tissues and have a negative impact on health. The aim of this review is to give an overview of the presence of phthalates and their hazards. Therefore, the use of these plastic additives should be reduced, replaced and their disposal improved.

Multiple Assays on Non-Target Organisms to Determine the Risk of Acute Environmental Toxicity in Tebuconazole-Based Fungicides Widely Used in the Black Sea Coastal Area

The widespread use of Tebuconazole-based fungicides in phytosanitary treatments on a wide range of crops, on the one hand, and the lack of official reports on the amount of fungicide residues in nearby water basins, on the other hand, may lead to uncontrolled and hazardous contamination of water sources used by the resident population, and to serious effects on the environment and public health. Our study explores the acute toxicological risk of this fungicide on various organisms, from bacteria and yeast to fish, using a battery of tests (standardized Toxkit microbiotests and acute semi-static tests). By investigating the interaction between Tebuconazole and bacteria and yeast organisms, we observed that Gram-negative bacteria displayed a strong tolerance for Tebuconazole, while Gram-positive bacteria and yeasts proved to be very sensitive. The fish experiment was conducted on Chelon auratus juveniles exposed to five concentrations of the fungicide Tebustar EW (Tebuconazole, 250 g/L as active substance). After 96 h of exposure, the LC₅₀ for C. auratus was 1.13 mg/L. In the case of the Toxkit microbiotests' application, the following results were recorded: Spirodela polyrhiza EC₅₀ = 2.204 mg/L (after 72 h exposure), Thamnocephalus platyurus EC₅₀ = 0.115 mg/L (after 24 h), and Daphnia magna EC₅₀ = 2.37 mg/L (after 24-48 h). With the exception of bacteria and yeast, the same response pattern was observed for all non-target species tested; the response range expressed by concentrations causing growth inhibition or mortality was small, ranging between very close values that are quite low, thereby demonstrating the high toxicity of Tebuconazole-based fungicides to the environment.

Rainbow trout (Oncorhynchus mykiss) physiological response to microplastics and enrofloxacin: Novel pathways to investigate microplastic synergistic effects on pharmaceuticals

Enrofloxacin (ENR) is a broad-spectrum antibiotic widely used due to its efficacy against pathogens. Microplastics (MPs) may bind to ENR and reduce its efficiency, whereas there would be an increase in its toxicity, bioavailability, and bio-accumulation rates. Therefore, the hypothesis is that the interaction between MPs and ENR can alter their toxicity and bioavailability. The subjective of this study is to examine the toxicity of various concentrations of ENR (0, 1.35, and 2.7 ml Kg^-1 diet) and MPs (0, 1000, and 2000 mg Kg^-1 diet) alone and in combination for 21 days. The rainbow trout (Oncorhynchus mykiss) is an economic aquaculture species used as an experimental model in ecotoxicology studies. Blood biochemical analytes indicated that ENR and MPs combination led to increasing enzymatic activity of each biomarker, except for gamma-glutamyl-transferase (GGT). Alterations related to triglycerides, cholesterol, glucose, urea, creatinine, total protein, and albumin blood contents were observed. An elevation in the levels of superoxide dismutase (SOD), malondialdehyde (MDA), and glucose 6-phosphate dehydrogenase (G6PDH) was found in the liver. In contrast, catalase (CAT) and glutathione peroxidase (GPx) levels decreased. Furthermore, a decline was observed in the cellular total antioxidant (ANT) levels. These findings suggested that ENR and MPs could affect fish health both independently and together. Consequently, the study determined that when both ENR and MPs were present in high concentrations, the toxicity of ENR was amplified, providing further evidence of the synergistic impact of MPs on ENR toxicity.

Short-term in vitro exposure of Pinctada imbricata's haemocytes to Quaternium-15: exploring physiological and cellular responses

Since the 2000s, the pearl oyster Pinctada imbricata (Röding, 1798) has become established along the transitional waterways of the "Capo Peloro Lagoon" natural reserve, where it is now abundant due to its adaptability to different hydrological, climatic, environmental, and pollution conditions. This study aims to evaluate haemocyte immune-mediated responses in vitro to quaternium-15, a common pollutant in aquatic ecosystems. Cell viability and phagocytosis activity decreased when exposed to 0.1 or 1mg/L of quaternium-15. Moreover, decreasing phagocytosis was confirmed by gene expression modulation of actin, involved in cytoskeleton rearrangement. Effects on oxidative stress-related genes were also assessed (Cat, MnSod, Zn/CuSod, GPx). The qPCR data revealed alterations in antioxidant responses through gene dose- and time-dependent modulation. This study presents insights into the physiological responses and cellular mechanisms of P. imbricata haemocytes to environmental stressors, indicating that this species is useful as a novel bioindicator for future toxicological studies.

Characterization of microplastics and its Pollution load index in freshwater Kumaraswamy Lake of Coimbatore, India

Microplastics are less than 5mm in diameter that enters the ecosystem through the breakdown of large plastic particles or climate and human activity. This study examined the geographical and seasonal distribution of microplastics in the surface water of Kumaraswamy Lake, Coimbatore. During seasons, including summer, pre-monsoon, monsoon, and post-monsoon, samples were collected from the lake's inlet, centre, and outlet. All sampling points contained linear low-density polyethylene, high-density polyethylene, polyethylene terephthalate, and polypropylene microplastics. Water samples contained fibre, thin, fragment, and film microplastics in black, pink, blue, white, transparent, and yellow colours. Lake's microplastic pollution load index was under 10, indicating risk I. Over four seasons, microplastic content was 8.77±0.27 particles per litre. The monsoon season had the highest microplastic concentration, followed by pre-monsoon, post-monsoon, and summer. These findings imply that the spatial and seasonal distribution of microplastics may be harmful to the fauna and flora of the lake.

Assessment of the effects of non-phthalate plasticizer DEHT on the bivalve molluscs Mytilus galloprovincialis

Due to their uncontrolled use, plastics has become an environmental concern, not only for their varying dimension but also for the potential release of substances such as phthalates (PAEs) and non-phthalates (NPPs) into the water. Phthalates are the most common plasticizers of concern, but non-phthalate plasticizers such as di (2-ethylhexyl) terephthalate (DEHT) have also been lately found in the marine environment. Mytilus galloprovincialis is a well-known bioindicator of aquatic environments due to its ability to accumulate a wide variety of xenobiotics, including plasticizers. Hence, aim of this study was to evaluate the potential bioaccumulation and effects of the NPP DEHT on M. galloprovincialis. To this purpose, following exposure to DEHT at 1 mg/l (DEHT1) and 100 mg/l (DEHT100), its accumulation in tissues and its effects on total lipids and fatty acid (FA) composition, protein content, cell viability, ability to recover volume and changes in biomarkers of oxidative stress were assessed. Mussels were able to bioaccumulate DEHT in their tissues, with a statistically significant increase compared to the control organisms. Differences in FA composition were observed after exposure, since C16:0, C18:0, C20:5ω-3 and C22:6ω-3 were significantly decreased from control to exposed groups. As a result, total SFA, MUFA and PUFA were affected in DEHT-exposed groups. Also, total protein varied following DEHT exposure, and significantly decreased in the DEHT100-group. Considering the physiological responses, both DEHT-exposed groups lost their ability to return to the original volume of digestive gland (DG) cells. On the other hand, oxidative biomarkers in the gills and DG were not significantly affected by the DEHT exposure. Overall, this study showed for the first time that DEHT exposure differentially affect mussels, in their lipid and protein metabolism, as well as cellular parameters.

Behavioral toxicity, histopathological alterations and oxidative stress in Tubifex tubifex exposed to aromatic carboxylic acids- acetic acid and benzoic acid: A comparative time-dependent toxicity assessment

This study evaluated Acetic acid (AA) and Benzoic acid's (BA) acute and sublethal toxicity by observing mortality, behavioral responses, and changes in the levels of oxidative stress enzymes in Tubifex tubifex. Exposure-induced changes in antioxidant activity (Catalase, Superoxide dismutase), oxidative stress (Malondialdehyde concentrations), and histopathological alterations in the tubificid worms were also noted across exposure intervals. The 96 h LC₅₀ values of AA and BA to T. tubifex were 74.99 and 37.15 mg/l, respectively. Severity in behavioral alterations (including increased mucus production, wrinkling, and reduction in clumping) and autotomy showed concentration-dependent trends for both toxicants. Although histopathological effects also showed marked degeneration in the alimentary and integumentary systems in highest exposure groups (worms exposed to 14.99 mg/l for AA and 7.42 mg/l for BA) for both toxicants. Antioxidant enzymes (catalase and superoxide dismutase) also showed a marked increase of up to 8-fold and 10-fold for the highest exposure group of AA and BA respectively. While species sensitivity distribution analysis revealed T. tubifex as most sensitive to AA and BA compared to other freshwater vertebrates and invertebrates, General Unified Threshold model of Survival (GUTS) predicted individual tolerance effects (GUTS-IT), with slower potential for toxicodynamic recovery, as a more likely pathway for population mortality. Study findings demonstrate BA with greater potential for ecological effects compared to AA within 24 h of exposure. Furthermore, ecological risks to critical detritus feeders like T. tubifex may have severe implications for ecosystem services and nutrient availability within freshwater habitats.

Effects of cadmium chloride and biofertilizer (Bacilar) on biochemical parameters of freshwater fish, Alburnus mossulensis

Fish in wild are often faced with various types of xenobiotics, that may display synergistic or antagonistic effects. In this study, we aim to examine how exposure to agrochemical compound (Bacilar) and cadmium (CdCl₂) alone and in combination affect biochemical parameters (lactate dehydrogenase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyl transferase, alanine aminotransferase; creatine phosphokinase (CKP), cholinesterase) and oxidative stress (total antioxidant capacity, catalase, malondialdehyde and protein carbonyl concentrations) of freshwater fish Alburnus mossulensis. Fish were exposed to two concentrations of Bacilar (0.3, and 0.6 mL L^-1) and to 1 mg L^-1 cadmium chloride alone and in combination for 21 days. Results showed that fish accumulate Cd in their body, with the highest rate in individuals exposed to Cd in combination with Bacilar. Both xenobiotics in fish liver induced the activation of liver enzymes suggesting hepatotoxic effects, with the greatest impact in co-exposed groups. A significant decrease in the hepatocyte's total antioxidant capacity indicates the collapse of the antioxidant defense in fish exposed to Cd and Bacilar. A decrease in the antioxidant biomarkers was followed by increased oxidative damage of lipids and proteins. We also reported altered function in the muscle of individuals exposed to Bacilar and Cd seen as decreased activities in CKP and butyrylcholinesterase. Overall, our results point to the toxicity of both Bacilar and Cd on fish but also to their synergistic effects on Cd bioaccumulation, oxidative stress, and liver and muscle damage. This study highlights the need for evaluating the use of agrochemicals and their possible additive effects on non-target organisms.

Fitness assessment of Mytilus galloprovincialis Lamarck, 1819 after exposure to herbicide metabolite propachlor ESA

The lack of data on the chronic effects of chloroacetanilide herbicide metabolites on non-target aquatic organisms creates a gap in knowledge about the comprehensive impacts of excessive and repeated pesticide use. Therefore, this study evaluates the long-term effects of propachlor ethanolic sulfonic acid (PROP-ESA) after 10 (T1) and 20 (T2) days at the environmental level of 3.5 μg.L^-1 (E1) and its 10x fold multiply 35 μg.L^-1 (E2) on a model organism Mytilus galloprovincialis. To this end, the effects of PROP-ESA usually showed a time- and dose-dependent trend, especially in its amount in soft mussel tissue. The bioconcentration factor increased from T1 to T2 in both exposure groups - from 2.12 to 5.30 in E1 and 2.32 to 5.48 in E2. Biochemical haemolymph profile and haemocyte viability were not affected by PROP-ESA exposure. In addition, the viability of digestive gland (DG) cells decreased only in E2 compared to control and E1 after T1. Moreover, malondialdehyde levels increased in E2 after T1 in gills, and DG, superoxidase dismutase activity and oxidatively modified proteins were not affected by PROP-ESA. Histopathological observation showed several damages to gills (e.g., increased vacuolation, over-production of mucus, loss of cilia) and DG (e.g., growing haemocyte trend infiltrations, alterations of tubules). This study revealed a potential risk of chloroacetanilide herbicide, propachlor, via its primary metabolite in the Bivalve bioindicator species M. galloprovincialis. Furthermore, considering the possibility of the biomagnification effect, the most prominent threat poses the ability of PROP-ESA to be accumulated in edible mussel tissues. Therefore, future research about the toxicity of pesticide metabolites alone or their mixtures is needed to gain comprehensive results about their impacts on living non-target organisms.

Exploring the Impact of Contaminants of Emerging Concern on Fish and Invertebrates Physiology in the Mediterranean Sea

In this historical context, the Mediterranean Sea faces an increasing threat from emerging pollutants such as pharmaceuticals, personal care products, heavy metals, pesticides and microplastics, which pose a serious risk to the environment and human health. In this regard, aquatic invertebrates and fish are particularly vulnerable to the toxic effects of these pollutants, and several species have been identified as bio-indicators for their detection. Among these, bivalve molluscs and elasmobranchs are now widely used as bio-indicators to accurately assess the effects of contaminants. The study focuses on the catshark Scyliorhinus canicular and on the Mediterranean mussel Mytilus galloprovincialis. The first one is a useful indicator of localised contamination levels due to its exposure to pollutants that accumulate on the seabed. Moreover, it has a high trophic position and plays an important role in the Mediterranean Sea ecosystem. The bivalve mollusc Mytilus galloprovincialis, on the other hand, being a filter-feeding organism, can acquire and bioaccumulate foreign particles present in its environment. Additionally, because it is also a species of commercial interest, it has a direct impact on human health. In conclusion, the increasing presence of emerging pollutants in the Mediterranean Sea is a serious issue that requires immediate attention. Bivalve molluscs and elasmobranchs are two examples of bio-indicators that must be used to precisely determine the effects of these pollutants on the marine ecosystem and human health.

Impact of acute and sub-acute exposure of magnesium oxide nanoparticles on mrigal Cirrhinus mrigala

This experiment was conducted to investigate the impact of acute and sub-acute exposure of magnesium oxide nanoparticles on Mrigal Cirrhinus mrigala. For sub-acute tests 1/100,1/50,1/10 were selected based on the LC₅₀ at 96 h s. Protein, carbohydrate, and lipid, Aspartate aminotransferase, alanine transaminase, lactate dehydrogenase and DPPH, HRSA assays were analyzed in the gill, muscle, and liver of Mrigal. Protein and lipid levels increased on the 7th,14th day compared to control. Carbohydrate levels decreased on the 7th,14th day of exposure, and the enzymatical changes increased on the 7^th,14th day. Antioxidant levels highly increased in DPPH assay compared to the HRSA assay. This study provides the biochemical, antioxidant, and behavioral changes in relation to the exposure of MgO NPs.

Combined effect of microplastic, salinomycin and heating on Unio tumidus

Microplastic (MP) and heating (T) suspected to modulate biological effects of aquatic contaminants. Salinomycin (Sal) is veterinary antibiotic and anticancer agent. The goal of this study was to examine the multistress effect of MP, Sal and T on the bioindicator bivalve mollusc. The Unio tumidus were treated with MP (1 mg L^-1), Sal (0.6 µg L^-1), their combination under 18° C (Mix) and 25° C (MixT) for 14 days. The digestive glands were analyzed. MP and Sal did not cause changes of Mn- and Cu,Zn-SOD, lipid peroxidation and Cyp-450-depended EROD levels, whereas catalase, GST and protein carbonyls (Sal-group) increased compared to control. In the Mix-group, enzymes, particularly EROD and GST (by 34% and 115% respectively) were up-regulated. However, in the MixT-group, they were corresponding to control or lesser (EROD, catalase). Our findings emphasize the need to take into account multistress interactions in the MP environmental risk assessment.

Contamination by Trace Elements and Oxidative Stress in the Skeletal Muscle of Scyliorhinus canicula from the Central Tyrrhenian Sea

Marine pollution, due to the regular discharge of contaminants by various anthropogenic sources, is a growing problem that imposes detrimental influences on natural species. Sharks, because of a diet based on smaller polluted animals, are exposed to the risk of water contamination and the subsequent bioaccumulation and biomagnification. Trace elements are very diffuse water pollutants and able to induce oxidative stress in a variety of marine organisms. However, to date, studies on sharks are rather scarce and often limited to mercury. In this context, the present study aimed to analyze the accumulation of trace elements and their putative correlation with the onset of an oxidative status in the muscle of the lesser spotted dogfish Scyliorhinus canicula, from the Central Mediterranean Sea. Ecotoxicological analysis detected the presence of Pb, As, Cd, Mn, Zn, Ni, Cu, and Fe; no significant differences were observed between sexes, while a negative correlation was found between Pb and animal length. Analysis of oxidative stress markers showed either positive or negative correlation with respect to the presence of trace elements. Lipid peroxidation (TBARS) positively correlated with Zn, Ni, and Fe; SOD enzyme activity negatively correlated with Cu and Ni; LDH was negatively correlated with Fe and positively correlated with Pb. Moreover, positive correlations between the leukocyte count and Mn and Zn, as well as with LDH activity, were also observed. The data suggested that, in sharks, trace elements accumulation may affect oxidant and antioxidant processes with important outcomes for their physiology and health.

Hemocytes: A Useful Tool for Assessing the Toxicity of Microplastics, Heavy Metals, and Pesticides on Aquatic Invertebrates

Invertebrates have long been an important tool for assessing water pollution due to their characteristics as intermediate consumers in aquatic ecosystem food chains. Most of the time, the effects of contaminants are measured by their effect on oxidative status or by mortality, although there already exists an easier tool-hemocytes. Hemocytes are circulating cells with a very important role in the immune system of invertebrates, which can be found within the hemolymph, analogous to the blood in vertebrates. The collection of hemolymph samples is easy, fast, minimally invasive, and poses no danger to the life of invertebrates. The purpose of this review was to highlight the advantages of using hemolymph for toxicity assays of various substances, including heavy metals, micro- and nano-plastics, pesticides, hydrocarbons, and oil spills. A literature search was conducted for this purpose using the most common and most often used databases, with a focus on the most recent and relevant studies. Bivalve mollusks, crustaceans, and gastropods were chosen for this investigation. This review found a growing number of studies choosing to use hemolymph as the standard methodology for toxicology assays, confirming their qualities as reliable tools.