Ecotoxicological effects of lanthanum in Mytilus galloprovincialis: Biochemical and histopathological impacts

Ecotoxicity of bioinsecticide spinosad to soil organisms: Commercial formulation versus active ingredient

Spintor® (SPIT®) is a commercial formulation of a bioinsecticide with the active ingredient Spinosad (SPIN). Despite the efforts of regulatory agencies, there still is a lack of information regarding short- and long-term exposures to soil-dwellers, as well as effects at environmentally relevant concentrations. This work aimed to evaluate the effects of SPIT® and SPIN, on the oligochaete Eisenia fetida, and the arthropod Folsomia candida. For this, natural soil was spiked with environmentally relevant concentrations (0.00-1.49 mg of the active ingredient·kg-1 of dry soil) to assess avoidance behaviour in E. fetida and reproduction effects on both species. Further, in E. fetida adults exposed for 2- and 28-day biomarkers of oxidative stress, energetic reserves, neurotoxicity and genotoxicity were evaluated. A significant reduction in juvenile production for F. candida was observed for SPIT® at ≥0.66 mg kg-1 and SPIN at ≥0.13 mg kg-1, and although no effect was observed on E. fetida reproduction, the oligochaeta revealed a tendency to avoid soil spiked with SPIT® at 0.44, 0.66 and 1.49 mg kg-1. The sub-individual responses of E. fetida demonstrate genotoxicity upon exposure to SPIT® and SPIN for 2 days. The 2-day exposures of SPIT® and SPIN seem to induce defence mechanisms, and in general, SPIN exerted higher effects than SPIT® on the oligochaetes. Overall, the pro-oxidant performance and energy metabolism pathways were disrupted in both exposures to SPIT® and SPIN. The results suggest that spinosyns-based products can have an impact on soil arthropods F. candida and oligochaete's health, possibly affecting their essential functions in terrestrial ecosystems.

Complex interactions of rare earth elements in aquatic systems: Comparing observed and predicted cellular responses on Mytilus galloprovincialis

Recent societal and technological developments have led to new sources of contamination, particularly from electronic waste (e-waste). The rapid increase in e-waste, combined with inadequate disposal and recycling practices has resulted in rising levels of hazardous substances in aquatic systems, including rare-earth elements (REEs). However, the effects of REEs on aquatic organisms remain poorly understood. This lack of understanding is concerning since REEs can simultaneously appear in aquatic systems. Thus, this study aimed to evaluate the impacts of Yttrium (Y), Lanthanum (La), and Gadolinium (Gd), individually and as mixtures on the mussel species Mytilus galloprovincialis. Biomarkers related to metabolism, energy reserves, defence enzymes, redox balance, cellular damage, and neurotoxicity were analyzed. The results obtained showed that Y alone caused minimal stress, while Gd, La, and their mixtures induced from moderate to severe stress, increasing metabolic activity, and enzyme responses. This study highlights the ecological impacts of REEs mixtures on aquatic organisms. The complex interactions and additive effects, especially with Gd, underline the need for further research on contaminant mixtures.

Unravelling biochemical responses in the species Mytilus galloprovincialis exposed to the antineoplastics ifosfamide and cisplatin under different temperature scenarios

This study investigates the chronic impact of two of the most widely consumed antineoplastic drugs, Ifosfamide (IF) and Cisplatin (CDDP), on the bivalve species Mytilus galloprovincialis under current (17 °C) and predicted warming conditions (21 °C). Accompanying the expected increase in worldwide cancer incidence, antineoplastics detection in the aquatic environment is also expected to rise. Mussels were exposed to varying concentrations of IF (10, 100, 500 ng/L) and CDDP (10, 100, 1000 ng/L) for 28 days. Biochemical analyses focused on metabolic, antioxidant and biotransformation capacities, cellular damage, and neurotoxicity. Results showed temperature-dependent variations in biochemical responses. Metabolic capacity remained stable in mussels exposed to IF, while CDDP exposure increased it at 1000 ng/L for both temperatures. Antioxidant enzyme activities were unaffected by IF, but CDDP activated them, particularly at 21 °C. Biotransformation capacity was unchanged by IF but enhanced by CDDP. Nevertheless, cellular damage occurred at CDDP concentrations above 100 ng/L, regardless of temperature. Integrated biomarker responses highlighted CDDP's greater impact, emphasizing the critical role of temperature in shaping organismal responses and underscoring the complexity of environmental stressor interactions.

Acute and chronic toxicity of rare earth elements-enriched sediments from a prospective mining area: Effects on life history traits, behavioural and physiological responses of Gammarus fossarum (Crustacea Amphipoda)

Rare earth elements (REE) have an essential role and growing importance in the world's economy. They are attracting interest from society, policymakers, and scientists. The rapidly growing global demand for REE in several strategic industrial and agricultural sectors led many countries to consider the (re)-opening of mining activities for REE extraction. Hence, their increasing use led to the disruption of their biogeochemical cycles with anthropic abnormalities already observed in aquatic ecosystems. Nonetheless, REE remain less studied, and their mechanisms of toxicity actions are not fully understood. As amphipods, Gammarus fossarum represent an important part of the aquatic macroinvertebrate assemblage and are generally used in ecotoxicological studies for their high ecological relevance. However, their use for the study of REE effects has been rather limited so far. The current study aims to assess the potential effects of two naturally REE-enriched sediments (N2 and B4) on G. fossarum. Effects on life history traits, behavioural and physiological responses have been evaluated. Exposing G. fossarum males for 72h to sediments N2 and B4 led to a decrease in haemolymph osmolality and locomotion while an increase in ventilatory activity was observed. Exposing G. fossarum pre-copula pairs with females at the same reproductive stage to the naturally REE-enriched sediments, for one moult cycle duration (∼30 days) showed that sediment B4 led to i) a significant uptake of REE, ii) a significant decrease in the proportion of females with oocytes and iii) a significant reduction in the total number of juveniles. The physicochemical analyses of sediments showed that B4 contains the highest amount of REE with a higher proportion of light REE. The present study gives the first insights into the potential toxicity of REE on G. fossarum as they may have deleterious effects on G. fossarum population's dynamics, which may alter the functioning of aquatic ecosystems.

Multiple-biomarker approach in the assessment of bisphenol A effect on the grooved carpet clam Ruditapes decussatus (Linnaeus, 1758)

BACKGROUND

Bisphenol A (BPA), a plastic additive monomer, is among the most highly produced chemicals worldwide, and is broadly used in many industries, such as food and beverage containers, milk bottles, and paper products. Previous studies demonstrated that BPA has potential toxicity to aquatic organisms, causing endocrine disturbance and behavioural disorders. The current work aimed to determine the toxic impacts of BPA on the edible marine clam Ruditapes decussatus considering a multi-biomarker approach (mortality, biochemical studies, DNA strand breaks using comet assay, and histopathological examinations with semi-quantitative and quantitative histopathological analyses). The clams were exposed under laboratory conditions to three concentrations of BPA (0 "control", 1, and 5 µg/L) for a period of 21 days. After the exposure period, BPA impacts were assessed in the digestive gland as a versatile and environmentally relevant organ for ecotoxicological studies.

RESULTS

In BPA-treated clams, mortality (10%) occurred only at the highest BPA concentration (5 µg/L). Biochemical impairments were detected in a concentration-dependent manner as a consequence of BPA exposure. There were significant increases in malondialdehyde (MDA) and glutathione (GSH) levels, while catalase (CAT) activity was significantly reduced. Our results revealed that BPA induced neurotoxicity in R. decussatus, as evidenced by the inhibition of acetylcholinesterase (AChE) activity in a dose-dependent manner. Furthermore, DNA damage was strongly induced as BPA levels increased. Additionally, our results have been affirmed by alterations in digestive gland tissues at BPA treatments, which consequently can impair the clam's ability for food absorption; these alterations included mainly atrophic and necrotic digestive tubules, epithelial cell vacuolization, hemocyte infiltration, and intertubular fibrosis. Based on the data obtained from the semi-quantitative and quantitative histopathological analyses, the exposure of the clam's digestive gland to BPA with concentrations of 1 and 5 µg/L for 21 days showed significant histopathological alterations compared with the control clams.

CONCLUSION

The multi-biomarker approach used in the current study proved to be a useful tool for assessing the impact of diphenylmethane compounds, such as BPA. Water-borne BPA causes oxidative stress, neurotoxicity, genotoxicity, and deleterious effects on the clam digestive gland; all of these could deteriorate clam performance and health, causing tissue dysfunction.

Insights into the combined toxicity and mechanisms of BDE-47 and PFOA in marine blue mussel: An integrated study at the physiochemical and molecular levels

The coexistence of multiple emerging contaminants imposes a substantial burden on the ecophysiological functions in organisms. The combined toxicity and underlying mechanism requires in-depth understanding. Here, marine blue mussel (Mytilus galloprovincialis L.) was selected and exposed to 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) and perfluorooctanoic acid (PFOA) individually and in combination at environmental related concentrations to elucidate differences in stress responses and potential toxicological mechanisms. Characterization and comparison of accumulation, biomarkers, histopathology, transcriptomics and metabolomics were performed. Co-exposure resulted in differential accumulation patterns, exacerbated histopathological alterations, and different responses in oxidative stress and biomarkers for xenobiotic transportation. Moreover, the identified differentially expressed genes (DEGs) and differential metabolites (DEMs) in mussels were found to be annotated to different metabolic pathways. Correlation analyses further indicated that DEGs and DEMs were significantly correlated with the above biomarkers. BDE-47 and PFOA altered the genes and metabolites related to amino acid metabolism, energy and purine metabolism, ABC transporters, and glutathione metabolism to varying degrees, subsequently inducing accumulation differences and combined toxicity. Furthermore, the present work highlighted the pivotal role of Nrf2-keap1 detoxification pathway in the acclimation of M. galloprovincialis to reactive oxygen species (ROS) stress induced by BDE-47 and PFOA. This study enabled more comprehensive understanding of combined toxic mechanism of multi emerging contaminants pollution.

The multistressor effect of pH reduction, microplastic and lanthanum on sea urchin Arbacia lixula

pH reduction (Low pH), microplastic (MP), and lanthanum (La) are substantial stressors due to their increasing trends in marine ecosystems and having adverse effects on marine species. This study investigates the single and combined effects of those stressors (Low pH: 7.45, polyethylene MP: 26 μg L-1, and La: 9 μg L-1) on the physiology and histology of sea urchin Arbacia lixula. Regarding physiological results, while the coelomocytes' quantity was slightly affected by stressors, their viability was significantly affected. The coelomocyte count and viability were suppressed most in Low pH-MP-La treatment. The stressors did not impact the respiration rate. According to the histological examination results, the crypt (villi-like structure) was shorter, and epithelial layers were thinner in single and dual stress treatments like MP, Low pH, Low pH-La, and MP-La. Overall, we suggest that the combination of variable types of those stressors causes negative effects on sea urchin's physiology and histology.

Praseodymium and warming interactions in mussels: Comparison between observed and predicted results

Being a crucial element for technological development, praseodymium (Pr) has been increasingly used, leading to a rise in its concentration in aquatic systems. However, its potential threats to organisms remain poorly understood. Besides contamination, organisms are also threatened by climate change-related factors, including warming. It is important to evaluate how climate change-related factors may influence the effects of contaminants. To address this, histopathological and biochemical analyses were performed in adult mussels of Mytilus galloprovincialis, following a 28-day exposure to Pr (10 μg/L) and warming (4 °C increase) separately, and in combination. Additionally, biochemical and physiological alterations were analysed in the sperm of mussels after 30-min exposure to the same treatments. Furthermore, it was used the Independent Action model to predict the interaction between Pr and warming. The results showed, in the case of adults exposed to Pr, an increase in superoxide dismutase (SOD) and glutathione S-transferases (GSTs) activities. However, it was insufficient, leading to histopathological injuries, redox imbalance, and cellular damage. In the case of sperm, Pr induced an increase of mitochondrial activity and respiration rate, in response to the increase in systemic metabolic rate and oxygen demand. Warming increased the metabolism, and induced redox imbalance and cellular damage in adults. In sperm, a rise in temperature induced lipid peroxidation and a decrease in velocity. Warming induced some alterations in how adult mussels responded to Pr, activating catalase instead of SOD, and in addition to GSTs, also activated carboxylesterases. However, it was not enough to avoid redox imbalance and cellular damage. In the case of sperm, the combination induced a decrease in H2O2 production, and higher oxygen demand, which prevented the decrease in motility and velocity. This study highlights the limitations of using models and emphasizes the importance of studying the impacts of emerging contaminants, such as rare earth elements, and their combination with climate change-related factors. Under environmental conditions, chronic exposure to the combined effect of different stressors might generate impacts at higher biological levels. This may affect organisms' respiratory and filtration capacity, nutrient absorption, defence capacity against infections or diseases, and sperm viability, ultimately resulting in reduced growth and reproduction, with consequences at the population level.

The role of the macroalgae Ulva lactuca on the cellular effects of neodymium and mercury in the mussel Mytilus galloprovincialis

Rare earth elements (REEs) are increasingly being studied mainly due to their economic importance and wide range of applications, but also for their rising environmental concentrations and potential environmental and ecotoxicological impacts. Among REEs, neodymium (Nd) is widely used in lasers, glass additives, and magnets. Currently, NdFeB-based permanent magnets are the most significant components of electronic devices and Nd is used because of its magnetic properties. In addition to REEs, part of the environmental pollution related to electrical and electronic equipment, fluorescent lamps and batteries also comes from mercury (Hg). Since both elements persist in ecosystems and are continuously accumulated by marine organisms, a promising approach for water decontamination has emerged. Through a process known as sorption, live marine macroalgae can be used, especially Ulva lactuca, to accumulate potential toxic elements from the water. Therefore, the present study aimed to evaluate the cellular toxicity of Nd and Hg in Mytilus galloprovincialis, comparing the biochemical effects induced by these elements in the presence or absence of the macroalgae U. lactuca. The results confirmed that Hg was more toxic to mussels than Nd, but also showed the good capability of U. lactuca in preventing the onset of cellular disturbance and homeostasis disruption in M. galloprovincialis by reducing bioavailable Hg levels. Overall, the biochemical parameters evaluated related to metabolism, antioxidant and biotransformation defences, redox balance, and cellular damage, showed that algae could prevent biological effects in mussels exposed to Hg compared to those exposed to Nd. This study contributes to the advancement of knowledge in this field, namely the understanding of the impacts of different elements on bivalves and the crucial role of algae in the protection of other aquatic organisms.

Evaluation of Possible Toxic Effects of Boric Acid in Palourde Clam (Ruditapes decussatus) Through Histological Changes and Oxidative Responses

The extensive utilization of boric acid, particularly in industrial and agricultural sectors, also engenders concerns regarding the toxicity of boron and its derivatives. Particularly, the behavior of boric acid at increasing concentrations in aquatic ecosystems remains poorly understood. In light of these concerns, this study aimed to investigate the toxicity of boric acid in bivalves, which occupy a critical position in the food chain. Specimens of Ruditapes decussatus, which had not been previously exposed to any pollutants and were cultivated under controlled conditions, were subjected to three different concentrations of boric acid (0.05 mg/L, 0.5 mg/L, and 5 mg/L) in vitro for 96 h. Following the exposure period, the specimens were assessed for histological changes (the mantle, gill, and digestive gland) and specific oxidative parameters (the gill and digestive gland), including superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase, and lipid peroxidation (LPO). The research findings indicated that boric acid primarily induced oxidative damage at the applied concentrations and increased antioxidant levels (p < 0.05). Moreover, although no significant histopathological abnormalities were observed in the examined histological sections, subtle changes were noted. This study evaluated the potential adverse effects of boric acid on bivalves, which are crucial components of the aquatic food chain, utilizing histological and specific physiological parameters following its introduction into aquatic environments. It is anticipated that the findings of this study will contribute to the development of new insights and perspectives regarding the extensive use of boric acid.

Evaluation of the health of Mediterranean mussels (Mytilus galloprovincialis Lamarck, 1819) distributed in the Çanakkale strait, Turkey

The observation of mortality in Mediterranean mussels (Mytilus galloprovincialis) distributed in the Çanakkale Strait in recent years was influential in developing the research question for this study. In this study, the presence of bacteria (Vibrio spp.) and parasites (Marteilia spp. and Haplosporidium spp.) in mussels collected from Kumkale, Kepez, and Umurbey stations in the Çanakkale Strait was investigated seasonally. Microbiological findings, histopathology, oxidative stress enzymes and their gene expressions, lipid peroxidation, lysosomal membrane stability, and changes in haemolymph were examined. In summer samples, both the defence system and the extent of damage were higher in gill tissue. In winter samples, enzyme activities and lipid peroxidation were found to be predominantly higher in digestive gland tissues. Histological examinations and Hemacolor staining revealed the presence of protozoan cysts, and for bacterial examination, molecular analysis performed after culturing revealed the presence of 7 Vibrio species. While the total numbers of heterotrophic bacteria detected in all samples were at acceptable levels, the predominance of Vibrio spp. numbers among the total heterotrophic bacteria detected in almost all samples were noteworthy. The total hemocyte count was calculated as 5.810(4)±0.58 (cells/mm3) in winter and 7.210(4)±1.03 (cells/mm3) in summer. These factors are considered to be possible causes of mussel mortality.

The role of warming in modulating neodymium effects on adults and sperm of Mytilus galloprovincialis

The use of rare earth elements (REEs) has been increasing and one of the most used is neodymium (Nd). Being an emergent contaminant, its negative impacts are poorly understood. Aquatic organisms are also threatened by climate change-related factors, as is the case of warming, which can change the effects of REEs. Thus, the impacts of Nd, warming, and the combination of both stressors were studied in adult mussels and sperm of the species Mytilus galloprovincialis, after an exposure period of 28 days (adults) and 30 min (sperm). The effects were evaluated through the analysis of biochemical and histopathological alterations in adults and biochemical and physiological responses given by sperm. The results showed that mussels only activated their biotransformation capacity when exposed to the stressors acting alone, which was insufficient to avoid lipid peroxidation. Furthermore, warming (alone and combined with Nd) also produces damage to proteins. The digestive gland was the most sensitive organ to Nd, presenting several histopathological alterations. In the case of sperm, all stressors induced lipid peroxidation, a higher oxygen demand, and a decrease in velocity, even if the sperm viability was maintained. It seems that warming influenced the effects of Nd to some extent. The present findings contribute significantly to the field of REEs environmental toxicology by offering valuable insights into the impacts of Nd on various biological levels of mussels. Additionally, within the context of climate change, this study sheds light on how temperature influences the effects of Nd. The obtained results indicate that both stressors can potentially compromise the overall health of mussel populations, thereby affecting other species reliant on them for food and habitat. Moreover, this study highlights impaired sperm health, which could adversely affect their reproductive capacity and ultimately lead to population decline.

Divergent perspectives on the synergistic impacts of thermal-chemical stress on aquatic biota within the framework of climate change scenarios

Climate change, including global warming, leads to rising temperatures in aquatic ecosystems, which is one of the numerous repercussions it brings. Furthermore, water warming can indirectly impact aquatic organisms by modifying the toxicity levels of pollutants. Nevertheless, numerous studies have explored the potential impacts of chemical stress on aquatic biota, but little is known about how such chemicals and toxins interact with climate change factors, especially elevated temperatures. As such, this review paper focuses on exploring the potential effects of thermochemical stress on a wide sector of aquatic organisms, including aquatic vertebrates and invertebrates, in various aquatic ecosystems (freshwater and marine systems). Herein, the objective of this study is to explore the most up-to-date the impact of water warming (without chemical stress) and thermochemical stress on various biochemical and physiological processes in aquatic fauna and how this greatly affects biodiversity and sustainability. Therefore, there is a growing need to understand and evaluate this synergistic mechanism and its potential hazardous impacts. However, we need further investigations and scientific reports to address this serious environmental issue in order to confront anthropogenic pollutants regarding climate change and chemical pollution risks in the near future and subsequently find sustainable solutions for them.

Removal of chromium(III) from contaminated waters using cobalt ferrite: how safe is remediated water to aquatic wildlife?

The release of hazardous elements by industrial effluents to aquatic ecosystems is a potential threat to the environment. Chromium (Cr) is one of the elements whose levels in several freshwater ecosystems should be reduced to promote water reuse. In recent years, magnetic materials have gained increasing interest as sorbents because of their easy removal from treated water through magnetic separation. In this study, colloidal cobalt ferrite (CoFe2O4) particles were investigated as magnetic sorbents for chromium-aqueous chemical species. The oxidative stress responses of Mytilus galloprovincialis mussels exposed to 200 μg/L of Cr, resembling remediated water, were evaluated. More than 95% of Cr was removed from contaminated solutions by CoFe2O4 aqueous suspensions at pH 6 and pH 10. The kinetics of sorption experiments were examined using pseudo-1st order, pseudo-2nd order and Elovich models to evaluate which mathematical model has a better adjustment to the experimental data. The present study revealed that the levels of Cr that remained in remediated water induced limited biochemical changes in mussels, being considered safe for aquatic systems. Overall, the use of cobalt ferrite-based sorbents may constitute a promising approach to remediate contaminated water.

Is Cladophora fracta an efficient tool of accumulating critical raw materials from wastewater and there a potential health risk of use of algae as organic fertilizer?

 In this study investigation of accumulations of critical raw materials (cobalt (Co), antimony (Sb), vanadium (V), lanthanum (La) and tungsten (W)) from wastewater by using C. fracta were aimed. Besides, assessment of the potential health risks in terms of the use of organic fertilizer obtained from the macroalga to be harvested from the treatment were also aimed. Highest Co, Sb, V, La and W accumulations by algae in reactor were 125±6.2%, 201.25±10%, 318.18±15%, 357.97±18%, and 500±25%, respectively. When compared with control, Co, Sb, V, La and W in algae increased 2.25, 3.01, 4.18, 4.58, and 6 times, respectively. The algae was very high bioaccumulative for Co and La. Highest MPI was calculated as 3.94. Non-carcinogenic risk of CRMs according to different exposure types (ingestion, inhalation, and dermal) were calculated for man, woman and child. There is not any non-carcinogenic risk from the investigated exposure ways of algae as organic fertilizer.

Mechanistic analysis of the sub chronic toxicity of La and Gd in Daphnia magna based on TKTD modelling and synchrotron X-ray fluorescence imaging

The release of lanthanides (Ln) into the environment has increased in recent decades due to their expanding applications in society. Studying their toxicity in aquatic ecosystems is urgent and challenging, with contradictory evidence presented in the literature. This study compared the biodistribution of La and Gd in Daphnia magna exposed to sub-chronic conditions and developed the first Toxicokinetic-Toxicodynamic (TKTD) model for these lanthanides with this model crustacean. D. magna were initially exposed for 7 days to concentrations close to the LC50 of La (2.10 mg L-1) and Gd (1.70 mg L-1). After exposure, half of the live daphnids were introduced in a clean media to allow depuration over 24 h, while the other organisms were directly prepared for synchrotron imaging measurements. Synchrotron X-ray fluorescence analysis revealed that metal distribution in the organisms was similar for both La and Gd, predominantly localized in the intestinal tract, even after the depuration process. These results indicate that ingested metal can adversely affect organisms under sub-chronic exposure conditions, highlighting the importance of using nominal concentrations as a more suitable indicator of metal bioavailability for risk assessment. The General Unified Threshold Model of Survival (GUTS) TKTD framework, in its reduced form (GUTS-RED), was developed for La and Gd using dissolved and nominal concentrations. D. magna were exposed for 7 days to concentrations from 0.5 to 5 mg L-1 of La or Gd and mortality monitored daily. The mechanistic model revealed a faster toxicokinetics for La than Gd and a higher toxicity for Gd than La in the organism. This study confirmed, despite similar chemical properties, the variation in both toxicity and toxicokinetics between these two metals.

From the cellular to tissue alterations induced by two rare earth elements in the mussel species Mytilus galloprovincialis: Comparison between exposure and recovery periods

The global effort to achieve carbon neutrality has led to an increased demand for renewable energy technologies and their raw materials, namely rare earth elements (REEs). These elements possess unique properties and are used in various applications. However, the increased use of REE-based technologies has resulted in higher amounts of electronic waste, leading to elevated REEs concentrations found in the aquatic environment, with poorly understood threats to wildlife. Praseodymium (Pr) and europium (Eu) are two REEs that, despite their potential environmental risks, have almost unknown effects on aquatic organisms. Therefore, the present study aimed to assess the impacts of different concentrations of Pr and Eu (0, 10, 20, 40, and 80 μg/L) in the mussel species Mytilus galloprovincialis, as well as their ability to recover from exposure to the highest concentration. Mussels accumulated both elements in a dose-dependent manner, with the accumulation of Pr being higher. Accompanying the increase of metabolism, mussels exposed to Pr not only enhanced the activity of the antioxidant enzymes superoxide dismutase (up to 40 μg/L) and glutathione reductase (at 80 μg/L) but also the activity of the biotransformation enzymes carboxylesterases (CbE's) and glutathione S-transferases (GSTs) (at 80 μg/L). Nevertheless, these defence mechanisms were not sufficient to prevent cellular damage. All the Eu concentrations induced cellular damage, despite an increase in the activity of biotransformation enzymes (CbE's and GSTs) in mussel tissue. According to the histopathology assessment, mussels were not able to recover after exposure to both elements and lower concentrations induced higher injuries in digestive tubules. This study highlights that exposure to Pr and Eu had adverse effects on M. galloprovincialis, even at the lowest tested concentration, which may eventually impact mussels' growth, reproductive capacity, and survival.

How predicted temperature and salinity changes will modulate the impacts induced by terbium in bivalves?

The threat of climate change, which includes shifts in salinity and temperature, has generated a global concern for marine organisms. These changes directly impact them and may alter their susceptibility to contaminants, such as terbium (Tb), found in electronic waste. This study assessed how decreased and increased salinity, as well as increased temperature, modulates Tb effects in Mytilus galloprovincialis mussels. After an exposure period of 28 days, Tb bioaccumulation and biochemical changes were evaluated. Results indicated no significant modulation of salinity and temperature on Tb accumulation, suggesting detoxification mechanisms and adaptations. Further analysis showed that Tb exposure alone caused antioxidant inhibition and neurotoxicity. When exposed to decreased salinity, these Tb-exposed organisms activated defense mechanisms, a response indicative of osmotic stress. Moreover, increased salinity also led to increased oxidative stress and metabolic activity in Tb-exposed organisms. Additionally, Tb-exposed organisms responded to elevated temperature with altered biochemical activities indicative of damage and stress response. Such responses suggested that Tb effects were masked by osmotic and heat stress. This study provides valuable insights into the interactions between temperature, salinity, and contaminants such as Tb, impacting marine organisms. Understanding these relationships is crucial for mitigating climate change and electronic waste effects on marine ecosystems.

Effects of rare earth element samarium doped zinc oxide nanoparticles on Mytilus galloprovincialis (Lamarck, 1819): Filtration rates and histopathology

BACKGROUND

Doping was reported to improve the photo catalytic performance, antioxidant, antibacterial and other biological properties of nanoparticles. While, improving the nanoparticle properties, doping could change toxicity profile to living organism. Hence, the aim of this work was to assess the effects of samarium doped zinc oxide nanoparticles (Sm doped ZnO NPs) on the edible mussel Mytilus galloprovincialis.

METHODS

Sm doped ZnO nanoparticles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) techniques. 156 mussels were exposed during 7 days to a low, intermediate and high concentration of Sm doped ZnO NPs (0.5, 1 and 1.5 mg/L, respectively). The filtration rates were assessed after 1 and 2 h. Histopathological alterations were determined in gills, digestive glands and gonads using a quantitative analysis.

RESULTS

The filtration rates decreased in all individuals exposed to Sm doped ZnO NPs, a significant decrease was noted with the low and intermediate concentration (0.5 and 1 mg/L) of Sm doped ZnO NPs after 1 and 2 h, respectively. The histopathological index (Ih) estimated for gills, digestive glands and gonads showed differences depending on the organ and the nanoparticle concentration. The highest Ih were reported for digestive glands and female gonads exposed to the intermediate concentration (1 mg/L) of Sm doped ZnO NPs. As for gills and male gonads, the highest Ih were noted with the high concentration (1.5 mg/L) of Sm doped ZnO NPs.

CONCLUSION

Results from this study revealed the toxicity of Sm doped ZnO NPs in Mytilus galloprovincialis gills, digestive glands and gonads. The toxicity induced by this nanoparticle varies depending on the organ and the concentration.

Fate, subcellular distribution and biological effects of rare earth elements in a freshwater bivalve under complex exposure

Rare earth elements (REE) are emerging contaminants due to their increased use in diverse applications including cutting-edge and green-technologies. Their environmental concerns and contradicting results concerning their biological effects require an extensive understanding of REE ecotoxicology. Thus, we have studied the fate, bioaccumulation and biological effects of three representative REE, neodymium (Nd), gadolinium (Gd) and ytterbium (Yb), individually and in mixture, using the freshwater bivalve Corbicula fluminea. The organisms were exposed for 96 h at 1 mg L-1 REE in the absence and presence of dissolved organic matter (DOM) reproducing an environmental contamination. Combined analysis of the fate, distribution and effects of REE at tissue and subcellular levels allowed a comprehensive understanding of their behaviour, which would help improving their environmental risk assessment. The bivalves accumulated significant concentrations of Nd, Gd and Yb, which were decreased in the presence of DOM likely due to the formation of REE-DOM complexes that reduced REE bioavailability. The accumulation of Nd, Gd and Yb differed between tissues, with gills > digestive gland ≥ rest of soft tissues > hemolymph. In the gills and in the digestive gland, Nd, Gd and Yb were mostly (>90 %) distributed among metal sensitive organelles, cellular debris and detoxified metal-rich granules. Gadolinium, Yb and especially Nd decreased lysosome size in the digestive gland and disturbed osmo- and iono-regulation of C. fluminea by decreasing Na concentrations in the hemolymph and Ca2+ ATPase activity in the gills. Individual and mixed Nd, Gd and Yb exhibited numerous similarities and some differences in terms of fate, accumulation and biological effects, possibly because they have common abiotic and biotic ligands but different affinities for the latter. In most cases, individual and mixed effects of Nd, Gd, Yb were similar suggesting that additivity approach is suitable for the environmental risk assessment of REE mixtures.

The influence of temperature on the effects of lead and lithium in Mytilus galloprovincialis through biochemical, cell and tissue levels: Comparison between mono and multi-element exposures

Lead (Pb) and lithium (Li) are metals which have been detected in the environment and, at high concentrations, can induce toxic effects that disturb the growth, metabolism or reproduction of organisms along the entire trophic chain. The impacts of these metals have scarcely been investigated using marine bivalves, especially when acting as a mixture. The present study aimed to investigate the influence of temperature on the ecotoxicological effects caused by Pb and Li, acting alone and as a mixture, on the mussel species Mytilus galloprovincialis after 28 days of exposure. The impacts were evaluated under actual (17 °C) and projected (+4 °C) warming conditions, to understand the influence of temperature rise on the effects of the metals (both acting alone or as a mixture). The results obtained showed that the increased temperature did not influence the accumulation of metals. However, the biomarkers evaluated showed greater responses in mussels that are exposed to metals under increased temperature (21 °C). The IBR index showed that there is a comparable toxic effect of Li and Pb separately, while exposure to a mixture of both pollutants causes a significantly higher stress response. Overall, the results obtained revealed that temperature may cause extra stress on the mussels and exposure to the metal mixture caused the greatest impacts compared to each metal acting alone.

Gadolinium accumulation and its biochemical effects in Mytilus galloprovincialis under a scenario of global warming

Electrical and electronic equipment reaching the end of its useful life is currently being disposed of at such an alarmingly high pace that raises environmental concerns. Together with other potentially dangerous compounds, electronic waste contains the rare-earth element gadolinium (Gd), which has already been reported in aquatic systems. Additionally, the vulnerability of aquatic species to this element may also be modified when climate change related factors, like increase in temperature, are taken into consideration. Thus, the present study aimed to evaluate the toxicity of Gd under a scenario of increased temperature in Mytilus galloprovincialis mussels. A multi-biomarker approach and Gd bioaccumulation were assessed in mussels exposed for 28 days to 0 and 10 μg/L of Gd at two temperatures (control - 17 °C; increased - 22 °C). Results confirmed that temperature had a strong influence on the bioaccumulation of Gd. Moreover, mussels exposed to Gd alone reduced their metabolism, possibly to prevent further accumulation, and despite catalase and glutathione S-transferases were activated, cellular damage seen as increased lipid peroxidation was not avoided. Under enhanced temperature, cellular damage in Gd-exposed mussels was even greater, as defense mechanisms were not activated, possibly due to heat stress. In fact, with increased temperature alone, organisms experienced a general metabolic depression, particularly evidenced in defense enzymes, similar to the results obtained under Gd-exposure. Overall, this study underlines the importance of conducting environmental risk assessment taking into consideration anticipated climate change scenarios and exposures to emerging contaminants at relevant environmental concentrations.

Evaluation of freshwater heavy metals accumulation effect on oxidative stress, Metallothionein biosynthesis and histopathology of Procambarus clarkii (Girard,1985) collected from three locations in the Delta region, Egypt

BACKGROUND

In this study, the effect of heavy metals accumulation influence was evaluated on adult crayfish Procambarus clarkii (Decapoda, Astacidea) collected from three different Governmental locations (Kafr El-Shaikh, El-Menofya, and El-Gharbiya) of the Egyptian Delta. The activity of super oxidase dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) of gills, hepatopancreas, and muscle tissue were measured. SDS Polyacrylamide gel electrophoresis (SDS-PAGE) and West blotting technique were performed to detect MT Protein expression.

RESULTS

The results revealed that Kafr El-Shaikh reflected the highest Superoxide dismutase (SOD), Catalase, and Glutathione S-transferase (GST) activity levels (97.2 u/100 mg, 28.5 u/100 mg, and 8.3 nmol mg (-1) protein min (-1) respectively. Superior protein polymorphism % (30%) remarked collected Freshwater crayfish P. clarkii from Kafr El-Shaikh location. Varied protein polymorphism % was shown between collected crayfish from El-Menofya, and El-Gharbiya locations (5.5 and 6.2 respectively) Increasing Metallothioneins intensity (15.4%) for collected Freshwater crayfish Procambarus clarkii from Kafr El-Shaikh Location.

CONCLUSION

Heavy metal stress influences antioxidant status and also induces increasing Metallothioneins intensity, especially samples that were collected from the Kafr El-Shaikh area.

Insights into environmental caffeine contamination in ecotoxicological biomarkers and potential health effects of Danio rerio

Caffeine (CAF) exposures have been shown to cause several pharmacological and biological effects in target and non-target organisms. Although there are already several ecotoxicological studies with CAF in non-target organisms, they are focused on marine organisms, with relevant concentrations in these ecosystems, therefore, less ecologically relevant to freshwater ecosystems (the main ecoreceptor of this type of anthropogenic contaminant). The present study aimed to assess the chronic effects (28 days) of sub-lethal and environmentally relevant concentrations of CAF (0.16, 0.42, 1.09, 2.84, 7.40, 19.23, and 50 μg/L) in Danio rerio. Biochemical endpoints as biomarkers of antioxidant defense, biotransformation, lipid peroxidation, energy sources, and neurotransmission were assessed. CAF exposure induced alterations in antioxidant defenses (superoxide dismutase and glutathione reductase activities, and glutathione content) preventing lipid peroxidation. Lactate dehydrogenase activity decreased in all the concentrations tested, while acetylcholinesterase activity was only affected by the highest concentrations tested (19.23 and 50 μg/L). We also utilized a multi-biomarker approach (Integrated Biomarker Response version 2, IBRv2) to investigate the effects of CAF in the dispersion scope of individual biochemical responses of D. rerio. IBRv2 showed that the concentration of 50 μg/L promotes the highest stress. However, the results showed that CAF induced disturbances in the metabolic pathways studied in D. rerio. These results demonstrated the toxic effects of CAF on freshwater fish, compromising their physiological functions and evidencing the need for monitoring the residues of CAF released into the inland aquatic environments. Furthermore, this research evidence that phylogenetically and physiologically different species may present different biological responses with concern for ecologically relevant environmental conditions. In this sense, the present study generated ecotoxicologically relevant data, that can be considered by environment regulators, since the here-endpoints evaluated showed sensitivity and consistency in the evaluation of caffeine risks in freshwater environments.

Behavioural and biochemical responses of the sea snail Tritia reticulata to lithium concentration gradient

Lithium (Li) is present in many modern technologies, most notably in rechargeable batteries. Inefficient recycling strategies for electronic waste containing this element may result in its release into aquatic systems, which may induce harmful effects on wildlife. The present study evaluated the effect of Li contamination on the gastropod Tritia reticulata exposed to different concentrations of Li (100, 200, 500 and 1000 µg L-1) for 21 days. Biochemical analyses showed that this species was not significantly affected by this contaminant at the cellular level, as no significant differences were observed in terms of metabolism, oxidative stress, and neurotoxicity. Results further revealed that snails attempted to avoid Li accumulation by burying in the sediment at a faster rate when exposed to the highest concentrations (500 and 1000 µg L-1). More research is needed to fully assess the response of T. reticulata to Li contamination, such as investigating longer exposure periods or other endpoints.

Ecotoxicological impacts of metals in single and co-exposure on mussels: Comparison of observable and predicted results

Used in high-tech and everyday products, mercury (Hg), cobalt (Co), and nickel (Ni) are known to be persistent and potentially toxic elements that pose a serious threat to the most vulnerable ecosystems. Despite being on the Priority Hazardous Substances List, existing studies have only assessed the individual toxicity of Co, Ni and Hg in aquatic organisms, with a focus on the latter, ignoring potential synergistic effects that may occur in real-world contamination scenarios. The present study evaluated the responses of the mussel Mytilus galloprovincialis, recognized as a good bioindicator of pollution, after exposure to Hg (25 μg/L), Co (200 μg/L) and Ni (200 μg/L) individually, and to the mixture of the three metals at the same concentration. The exposure lasted 28 days at 17 ± 1 °C, after which metal accumulation and a set of biomarkers related to organisms' metabolic capacity and oxidative status were measured. The results showed that the mussels could accumulate metals in both single- and co-exposure conditions (bioconcentration factors between 115 and 808) and that exposure to metals induced the activation of antioxidant enzymes. Although Hg concentration in organisms in the mixture decreased significantly compared to single exposure (9.4 ± 0.8 vs 21 ± 0.7 mg/kg), the negative effects increased in the mixture of the three elements, resulting in depletion of energy reserves, activation of antioxidants and detoxification enzymes, and cellular damage, with a hormesis response pattern. This study underscores the importance of risk assessment studies that include the effects of the combination of pollutants and demonstrates the limitations of applying models to predict metal mixture toxicity, especially when a hormesis response is given by the organisms.

Are Lithium batteries so eco-friendly? Ecotoxicological impacts of Lithium in estuarine bivalves

Lithium (Li) is now widely used in green energies/clean technologies, although its inefficient recycling and treatment means it is an emerging contaminant in aquatic systems. Bivalves, such as clams, are considered good bioindicators of pollution, hence we evaluated the biochemical effects of Li in the clam Venerupis corrugata. Clams were exposed (14 days) to an increasing Li gradient (0, 200, 400, 800µg/L). Bioconcentration capacity tended to decrease with increasing Li exposure possibly due to efforts to eliminate Li from the cells, to avert damage. No influences on the clams' metabolic capacity and protein content were observed. Antioxidant and detoxification defences were activated, especially at 400 and 800µg/L of Li, avoiding lipid damage while protein injuries were observed at higher concentrations. Furthermore, a loss of redox balance was observed. This study highlights the importance of preventing and regulating Li discharges into the environment, avoiding adverse consequences to aquatic ecosystems.

Assessing the impact of terbium on Mytilus galloprovincialis: Metabolic and oxidative stress responses

The increasing demand for electric and electronic equipment has led to a rise in potentially hazardous electronic waste, including rare-earth elements (REEs), such as terbium (Tb), which have been already detected in aquatic systems. This study investigated the biochemical effects of anthropogenic Tb on mussels over a 28-day period. The mussels were exposed to different concentrations of Tb (0, 5, 10, 20, 40 μg/L), and biomarkers related to metabolism, oxidative stress, cellular damage, and neurotoxicity were evaluated. Bioaccumulation of Tb in the mussels' tissue increased with exposure concentrations, but the bioconcentration factor remained similar between treatments. Exposure to Tb enhanced glycogen consumption and decreased metabolic capacity which could be seen as a physiological adaptation to limit Tb accumulation. Antioxidant defenses and glutathione S-transferases showed a more complex dose-response, with enzymatic responses increasing until 10 μg/L but then returning to control levels at 20 μg/L. At 40 μg/L, enzymatic responses were also enhanced but to a lower extent than at 10 μg/L. The presence of Tb had clearly an inhibitory effect on biotransformation enzymes such as carboxylesterases in a dose-dependent manner. Likely, thanks to biochemical and physiological adaptations, no cellular damage or neurotoxicity was observed in any treatments, confirming the mussels' ability to tolerate Tb exposure. Nevertheless, prolonged exposure to these concentrations could lead to harmful consequences when facing other environmental stressors, such as misallocating energy resources for growth, reproduction, and defense mechanisms.

Are the consequences of lithium in marine clams enhanced by climate change?

Coastal areas, such as estuaries and coastal lagoons, are among the most endangered aquatic ecosystems due to the intense anthropogenic activities occurring in their vicinity. These areas are highly threatened by climate change-related factors as well as pollution, especially due to their limited water exchange. Ocean warming and extreme weather events, such as marine heatwaves and rainy periods, are some of the consequences of climate change, inducing alterations in the abiotic parameters of seawater, namely temperature and salinity, which may affect the organisms as well as the behaviour of some pollutants present in water. Lithium (Li) is an element widely used in several industries, especially in the production of batteries for electronic gadgets and electric vehicles. The demand for its exploitation has been growing drastically and is predicted a large increase in the coming years. Inefficient recycling, treatment and disposal results in the release of Li into the aquatic systems, the consequences of which are poorly understood, especially in the context of climate change. Considering that a limited number of studies exist about the impacts of Li on marine species, the present study aimed to assess the effects of temperature rise and salinity changes on the impacts of Li in clams (Venerupis corrugata) collected from the Ria de Aveiro (coastal lagoon, Portugal). Clams were exposed for 14 days to 0 μg/L of Li and 200 μg/L of Li, both conditions under different climate scenarios: 3 different salinities (20, 30 and 40) at 17 °C (control temperature); and 2 different temperatures (17 and 21 °C) at salinity 30 (control salinity). Bioconcentration capacity and biochemical alterations regarding metabolism and oxidative stress were investigated. Salinity variations had a higher impact on biochemical responses than temperature increase, even when combined with Li. The combination of Li with low salinity (20) was the most stressful treatment, provoking increased metabolism and activation of detoxification defences, suggesting possible imbalances in coastal ecosystems in response to Li pollution under extreme weather events. These findings may ultimately contribute to implement environmentally protective actions to mitigate Li contamination and preserve marine life.

Algal sorbents and prospects for their application in the sustainable recovery of rare earth elements from E-waste

Efficient and sustainable secondary sourcing of Rare-Earth Elements (REE) is essential to counter supply bottlenecks and the impacts associated with primary mining. Recycled electronic waste (E-waste) is considered a promising REE source and hydrometallurgical methods followed by chemical separation techniques (usually solvent extraction) have been successfully applied to these wastes with high REE yields. However, the generation of acidic and organic waste streams is considered unsustainable and has led to the search for "greener" approaches. Sorption-based technologies using biomass such as bacteria, fungi and algae have been developed to sustainably recover REE from e-waste. Algae sorbents in particular have experienced growing research interest in recent years. Despite its high potential, sorption efficiency is strongly influenced by sorbent-specific parameters such as biomass type and state (fresh/dried, pre-treatment, functionalization) as well as solution parameters such as pH, REE concentration, and matrix complexity (ionic strength and competing ions). This review highlights differences in experimental conditions among published algal-based REE sorption studies and their impact on sorption efficiency. Since research into algal sorbents for REE recovery from real wastes is still in its infancy, aspects such as the economic viability of a realistic application are still unexplored. However, it has been proposed to integrate REE recovery into an algal biorefinery concept to increase the economics of the process (by providing a range of additional products), but also in the prospect of achieving carbon neutrality (as large-scale algae cultivation can act as a CO₂ sink).

Impact of Pb Toxicity on the Freshwater Pearl Mussel, Lamellidens marginalis: Growth Metrics, Hemocyto-Immunology, and Histological Alterations in Gill, Kidney, and Muscle Tissue

Pb is one of the most extensively used harmful heavy metals in Bangladesh, and its occurrence in waters affects aquatic organisms significantly. The tropical pearl mussel, Lamellidens marginalis, was exposed to different concentrations (T₁ 21.93 mgL^-1, T₂ 43.86 mgL^-1, and T₃ 87.72 mgL^-1) of Pb(NO₃)₂ and was evaluated against a control C 0 mgL^-1 of Pb(NO₃)₂, followed by a 96 h acute toxicity test. The LC₅₀ value was recorded as 219.32 mgL^-1. The physicochemical parameters were documented regularly for each treatment unit. The values of % SGR, shell weight, soft tissue wet weight, and weight gain remained statistically higher for the control group in comparison with the treatment. No mortality was noted for control units, while a gradually decreased survival rate was recorded for the different treatment groups. Fulton's condition factor was recorded as highest in the control and lowest in the T₃ unit, while the condition indices did not vary between the control and treatment groups. The hemocyte was accounted as maximum in the control and T₁, while minimum in T₂ and T₃. The serum lysosomal parameters also followed a similar pattern, and a significantly low level of lysosomal membrane stability, and serum lysosome activity was noted for T₃ and T₂ units in comparison to the control group. The histology of the gill, kidney, and muscle was well structured in the control group, while distinct pathologies were observed in the gill, kidney, and muscle tissue of different treatment groups. The quantitative comparison revealed that the intensity of pathological alteration increased as the dosage of Pb increased. The current study, therefore, indicated that intrusion of Pb(NO₃)₂ in the living medium significantly alters growth performance and hemocyte counts, and chronic toxicity induces histomorphological abnormalities in vital organs.

Antarctic toothfish Dissostichus mawsoni as a bioindicator of trace and rare earth elements in the Southern Ocean

The Antarctic toothfish Dissostichus mawsoni is a Southern Ocean long-lived top predator which is regularly captured on an annual fishery operating in the region. By its biological and ecological characteristics, it is a potential bioindicator for the concentrations of trace and rare earth elements in the Antarctic. As these elements are mainly transferred through the diet and a deficiency or excess of these elements can lead to diverse health problems, it is important to measure their concentrations on the organisms. This study provides, for the first time, the concentration of 27 trace (major essential, minor essential and non-essential) and rare earth elements in the muscle of D. mawsoni captured in three areas of the Amundsen and Dumont D'Urville Seas (Antarctica). Major essential elements had the highest concentrations, with potassium (K) as the most concentrated, and rare earth elements the lowest. Significant differences between areas were found for most of the studied elements. No bioaccumulation nor biomagnification potential was found for the studied elements, with several elements decreasing concentrations towards larger individuals. Decreasing trends are related with the different habitats occupied by D. mawsoni through their life, suggesting that elements' concentrations in the water is determinant for the concentrations in this top predator, and/or there is a dilution effect as the fish grows. Our results also support that Se presents a detoxification potential for Hg in D. mawsoni, but only when Hg concentrations are higher to unhealthy levels. This study supports D. mawsoni as a potential bioindicator for the concentrations of the different trace and rare earth elements in the Southern Ocean, though only when comparing individuals of similar size/age, but also to evaluate annual changes on their concentrations. Furthermore, D. mawsoni can be a good source of major essential elements to humans with concentrations of major essential elements above some of other marine fish worldwide.

Two-phase effects of environmentally relevant lanthanum on life-history traits of Daphnia magna and transgenerational bioenergetic profiles: Implications for nutritional and environmental consequences

The versatile applicability of rare earth elements (REEs) especially lanthanum (La) in diverse fields, has led to large-scale mineral exploitation globally, inevitably resulting in substantial release of La into environment. As emerging anthropogenic environmental contaminant, La-induced toxicological effects and potential ecotoxicological implications in relation to realistic levels of La in aquatic ecosystems are becoming major concerns. To address these issues, Daphnia magna was selected as a prototype, and toxicity tests were conducted to explore the effects of La exposure on life-history characteristics and fecundity fitness, as showcased by quantitative variations from the individual level to population scale. In parallel, to further denote transgenerational caloric impacts of parental La exposure, bioenergetic profiles on newborn neonates were concurrently determined by measuring macromolecule forms in terms of proteins, glycogens and lipids to quantify nutritional alterations at progeny level. The results revealed that low-dose La exposure slightly stimulated the demographic potential and nutritional responses, exhibiting dose-dependent hormesis-like effects and promising non-toxicological potential to Daphnia, whereas high-dose La exposure of greater than 59.2 µg La L ^- 1, conspicuously imposed detrimental effects on quantity and quality of offspring, i.e. not only reducing body size, lifespan expectancy and reproductive output in a concentration-dependent way and resulting in lower population fitness by a dynamic life-table analysis, but eventually leading to the decrease of nutritional qualities and caloric contents on neonates. Taken together, these two-phase findings regarding the dose-related shift from hormesis to inhibition not only provided valuable insights into the complicated biological outcomes of La effects on environmentally-relevant organisms, but experimentally highlighted the significant implications of considering environmental and nutritional consequences in ecologically assessing the La-triggered risk at environmentally realistic occurrences, particularly on gradient scenarios crossing upstream and downstream of highly complex mining watersheds.

How will different scenarios of rising seawater temperature alter the response of marine species to lithium?

Marine ecosystems are suffering from the gradual rise in temperature due to climate change. Warming scenarios and the intensification of extreme climate events, such as marine heatwaves (MHWs), have been negatively affecting marine organisms. In addition, they are also threatened by anthropogenic pollution. Lithium (Li) is an emerging pollutant that has become a major concern due to its increasing use in a variety of applications. Understanding its influence on marine environments in combination with warming scenarios is crucial, as very little is known about its impact on marine organisms, especially when also considering the increasingly concerning impacts of climate change. With this in mind, this research aimed to assess how different scenarios of increasing temperature may affect the response of Mytilus galloprovincialis to Li. Mussels bioaccumulation levels, as well as physiological and biochemical biomarkers were analyzed after 28 days of exposure to Li under different temperature scenarios (control - 17 °C; warming - 21 °C and marine heatwave - MHW). The results indicate that mussels accumulated Li, independently of the temperature scenario. The respiration rate was higher in contaminated mussels than in the non-contaminated ones, with no differences among temperature scenarios. Furthermore, the metabolic rate decreased in non-contaminated mussels exposed to 21 °C and MHW, while mussels exposed to the combination of Li and MHW presented the highest metabolic rate. The mussels exposed to MHW and Li evidenced the highest cellular damage but Li was not neurotoxic in M. galloprovincialis. This study highlighted that MHW + Li was the most stressful condition, inducing clear negative effects in this species that can impair the growth and reproduction of an entire population. In general, the presented results highlight the importance of future studies in which it is necessary to combine the effects of pollutants and climate change scenarios, namely extreme weather events such as MHWs.

Assessment of sulfamethoxazole toxicity to marine mussels (Mytilus galloprovincialis): Combine p38-MAPK signaling pathway modulation with histopathological alterations

Sulfamethoxazole (SMX), is a ubiquitous antibiotic in the aquatic environment and received concerns on its health hazards, especially its sub-lethal effects on non-target organisms which were remained largely unknown. In the present study, in order to investigate SMX induced tissue damages and reveal underlying mechanisms, marine mussels, Mytilus galloprovincialis were challenged to SMX series (0.5, 50 and 500 μg/L) for six-days followed by six-day-recovery. Comprehensive histopathological alteration (including qualitative, semi-quantitative and quantitative indices), together with transcriptional and (post-) translational responses of key factors (p38, NFκB and p53) in the p38-MAPK signaling pathway were analyzed in gills and digestive glands. Tissue-specific responses were clearly investigated with gills showing more prompt responses and digestive glands showing higher tolerance to SMX. The histopathology showed that SMX triggered inflammatory damages in both tissues and quantitative analysis revealed more significant responses, suggesting its potential as a valuable health indicator. SMX activated expressions of p38, NFκB and p53 at transcriptional and (post-) translational levels, especially after exposed to low level SMX, evidenced by p38 coupled with NFκB/p53 regulation on immunity defense in mussels. Less induction of targeted molecules under severe SMX exposure indicated such signaling transduction may not be efficient enough and can result in inflammatory damages. Taken together, this study expanded the understanding of aquatic SMX induced health risk in marine mussels and the underlying regulation mechanism through p38 signaling transduction.

Can temperature influence the impacts induced in Mytilus galloprovincialis by neodymium? Comparison between exposure and recovery periods

Climate change-associated factors and pollutants, such as rare earth elements (REEs), have been identified as contributors to environmental changes. However, the toxicity resulting from the combination of these stressors has received little attention. Neodymium (Nd) is a REE that has been widely used, and this study aimed to evaluate the responses of Mytilus galloprovincialis to Nd exposure (10 µg/L), under actual (17 °C) and predicted warming conditions (21 °C), after fourteen days of exposure followed by fourteen days of recovery (without Nd), analyzing Nd accumulation, histopathological and biochemical alterations. The results showed that increased temperature and Nd exposure caused histopathological injuries in the gills. Contaminated mussels at 17 °C showed cellular damage, while at 21 °C, mussels were able to avoid cellular damage. After the recovery period, no improvements in gill's status were found and cellular damage was still present, highlighting the impacts caused by previous exposure to Nd.

Threats of Pollutants Derived from Electronic Waste to Marine Bivalves: The Case of the Rare-Earth Element Yttrium

The production of electrical and electronic equipment waste (e-waste) is increasing at an alarming rate worldwide. This may eventually lead to its accumulation in aquatic environments, mainly because of the presence of nonbiodegradable components. The rare-earth element yttrium (Y) is particularly relevant because it is present in a wide variety of electro-based equipment. Within this context, the present study investigated the biological consequences of anthropogenic Y exposure in Mytilus galloprovincialis. Mussels were exposed to Y (0, 5, 10, 20, 40 μg/L) for 28 days, and their bioaccumulation and biomarkers related to metabolism, oxidative stress defenses, cellular damage, and neurotoxicity were evaluated. The results revealed that tissue Y content increased at increasing exposure concentrations (though the bioconcentration factor decreased). At the lowest Y dosage (5 µg/L), mussels lowered their electron transport system (ETS) activity, consumed more energy reserves (glycogen), and activated superoxide dismutase activity, thus preventing cellular damage. At the highest Y dosage (40 μg/L), mussels reduced their biotransformation activities with no signs of cellular damage, which may be associated with the low toxicity of Y and the lower/maintenance of ETS activity. Although only minor effects were observed, the present findings raise an environmental concern for aquatic systems where anthropogenic Y concentrations are generally low but still may compromise organisms' biochemical performance. Particularly relevant are the alterations in energy metabolism and detoxification processes for their longer-term impacts on growth and reproduction but also as defense mechanisms against other stressors. Environ Toxicol Chem 2023;42:166-177. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Toxicopathic effects of lithium in mussels

The rising use of lithium (Li) in industrial processes, modern technology and medicine has generated concerns in the scientific community, in particular its potential impact on the environment. Unfortunately, there is only scarce information concerning the toxicity of lithium in marine organisms. The objective of this study is to determine the toxicity of Li using Mytilus galloprovincialis as model organism, based on acute and sublethal toxicity tests. In the first experiment, mussels were exposed for 9 days to a range of acute concentrations of Li (0, 2, 5, 13, 34, 89, 233 and 610 mg/L Li) in order to find the median lethal concentration. In the sublethal experiment, mussels were exposed to environmentally relevant concentrations of Li (0, 0.1, 1, 10 mg/L Li) for 21 days. Digestive gland and gonad samples were taken at day 0, 1, 7 and 21 for histopathological analysis. Samples of the whole mussels were taken for chemical analysis at day 0 and after 21 days. Results showed that M. galloprovincialis had a LC50 value of 153 mg/L Li after 9 days of exposure. Lower concentrations (environmentally relevant), led to Li bioaccumulation in a dose-dependent manner and histopathological effects in a time-dependent manner. Atrophy of the digestive alveoli epithelium and degeneration of the digestive gland were observed after 21 days of exposure. These findings open new perspectives for the understanding of the toxic effects of Li on marine organisms and evidence the need for further long-term research at different levels of biological organizations.

Do climate change related factors modify the response of Mytilus galloprovincialis to lanthanum? The case of temperature rise

Most of the electric and electronic waste is not recycled and the release of its components into the environment is expected, including the rare-earth element Lanthanum (La), which has already been reported in the aquatic systems. Furthermore, considering climate change factors such as the predicted increase in temperature, the susceptibility of aquatic organisms to these rare elements may be modified. In light of this, the present study aimed to evaluate the relevance of temperature on La-derived effects in the mussel Mytilus galloprovincialis. Several biomarkers and La bioaccumulation were assessed in organisms exposed to 0 (control) and 10 μg/L of La at two distinct temperatures (17 and 22 °C) for 28 days. Results showed that temperature did not influence La bioaccumulation in mussels. However, exposure to La resulted in a decreased metabolic capacity and an enhancement of biotransformation enzymes activity, as a possible defense behavior of mussels to avoid La accumulation and toxicity. Nevertheless, antioxidant defenses were also inhibited leading to increased lipid peroxidation (LPO) levels. Warming alone seemed to cause a metabolic shutdown seen as reduced enzyme activities and protein carbonylation (PC) levels. Simultaneous La exposure and temperature rise caused combined effects on mussels, as they accused metabolic depression, biotransformation defenses activation, antioxidant capacity reduction, and higher cellular damage. Overall, this study highlights the need to perform environmental risk assessment studies, by considering emerging contaminants exposures at relevant concentrations, both at present and forecasted climate change scenarios.

Effects of Sulfamethoxazole on Fertilization and Embryo Development in the Arbacia lixula Sea Urchin

Simple Summary

Drugs released into the aquatic environment create serious problems for the organisms that live there. For this reason, the present study investigates the in vitro effects of the antibiotic sulfamethoxazole, widely found in wastewater, on the fertilization and development of the Arbacia lixula sea urchin. The results showed a significant reduction in the percentage of fertilized oocytes at the highest drug concentrations, together with an increase in anomalies and delays in the development of the embryo. Therefore, the data obtained suggest urgent intervention on the release of these drugs in order to prevent important alterations in the species’ development and to preserve biodiversity.

Abstract

To date, drugs released into the aquatic environment are a real problem, and among antibiotics, sulfamethoxazole is the one most widely found in wastewater; thus, the evaluation of its toxicity on marine organisms is very important. This study, for the first time, investigates the in vitro effects of 4 concentrations of sulfamethoxazole (0.05 mg/L, 0.5 mg/L, 5 mg/L, 50 mg/L) on the fertilization and development of the sea urchin Arbacia lixula. The gametes were exposed to drugs in three different stages: simultaneously with, prior to, and post-fertilization. The results show a significant reduction in the percentage of fertilized oocytes at the highest drug concentrations. Moreover, an increase in anomalies and delays in embryo development following the treatment with the drug was demonstrated. Therefore, the data suggest that this antibiotic can alter the development of marine organisms, making it urgent to act to reduce their release and to determine the concentration range with the greatest impact.

The impact of temperature on lithium toxicity in the gastropod Tritia neritea

The most important use of lithium (Li) is in rechargeable batteries. The growing use of Li, incorrect disposal of Li-based applications, and inefficient recycling strategies for their elimination will result in the release of this metal into the aquatic systems. Alongside with the impacts caused by pollutants, organisms in coastal ecosystems are also facing environmental changes as those related with climate change scenarios, namely, seawater temperature rise. In this context, the present study aimed to evaluate the influence of temperature on Li toxicity, using the Nassariid gastropod Tritia neritea as model species. Metabolism and oxidative stress related biomarkers were evaluated after a 28-day exposure period. The results demonstrated that temperature enhanced the toxic impacts of Li, most probably due to snail increased sensitivity when under warming conditions. As a consequence of inefficient antioxidant and biotransformation capacity, lipid peroxidation was observed in Li-contaminated snails at 21 ºC, demonstrating a significant interaction between both factors. Regarding snails' metabolic capacity, Li did not affect snails, but a clear decrease on their metabolism was observed at increased temperature (with or without Li) which may limit snail defense capacity. Overall, the present findings demonstrated the impacts derived from Li towards marine intertidal gastropods, evidencing enhanced threats under predicted warming conditions. Considering the role of T. neritea in the ecosystem functioning, impacts on this species may greatly affect other populations and eventually the entire community.

The effect of ocean warming on accumulation and cellular responsiveness to cobalt in Mytilus galloprovincialis

Cobalt (Co) is among the hazardous substances identified in aquatic environments. Industrialization and population growth have also contributed to climate change, namely in what concerns ocean temperature rise. The aim of the present study was to evaluate the influence of temperature rise on the impacts caused by Co on Mytilus galloprovincialis. To this end, mussels were exposed for 28 days to 17 °C and 21 °C, without and with 200 μg L^-1 of Co. Results showed no significant differences in Co bioaccumulation by the organisms between temperatures. A significant interaction between temperature and Co contamination was observed in terms of oxidative damage, detoxification capacity, and neurotoxicity, with a synergistic effect particularly evident in terms of biotransformation enzymes' activity. The obtained results point out that population survival and distribution may be limited in the long term, highlighting the need for future research on the combined effects of both stressors.

Single and combined ecotoxicological effects of ocean warming, acidification and lanthanum exposure on the surf clam (Spisula solida)

Lanthanum (La) is one of the most abundant emergent rare earth elements. Its release into the environment is enhanced by its use in various industrial applications. In the aquatic environment, emerging contaminants are one of the stressors with the ability to compromise the fitness of its inhabitants. Warming and acidification can also affect their resilience and are another consequence of the growing human footprint on the planet. However, from information gathered in the literature, a study on the effects of ocean warming, acidification, and their interaction with La was never carried out. To diminish this gap of knowledge, we explored the effects, combined and as single stressors, of ocean warming, acidification, and La (15 μg L^-1) accumulation and elimination on the surf clam (Spisula solida). Specimens were exposed for 7 days and depurated for an additional 7-day period. Furthermore, a robust set of membrane-associated, protein, and antioxidant enzymes and non-enzymatic biomarkers (LPO, HSP, Ub, SOD, CAT, GPx, GST, TAC) were quantified. Lanthanum was bioaccumulated after just one day of exposure, in both control and climate change scenarios. A 7-day depuration phase was insufficient to achieve control values and in a warming scenario, La elimination was more efficient. Biochemical response was triggered, as highlighted by enhanced SOD, CAT, GST, and TAC levels, however as lipoperoxidation was observed it was insufficient to detoxify La and avoid damage. The HSP was largely inhibited in La treatments combined with warming and acidification. Concomitantly, lipoperoxidation was highest in clams exposed to La, warming, and acidification combined. The results highlight the toxic effects of La on this bivalve species and its enhanced potential in a changing world.

Biochemical alterations caused by lanthanum and gadolinium in Mytilus galloprovincialis after exposure and recovery periods

The increasing use of rare earth elements (REEs) in electric and electronic equipment has been associated with the presence of these elements in aquatic systems. The present study aimed to evaluate the toxicity of two REEs, Lanthanum (La) and Gadolinium (Gd), towards the mussel species Mytilus galloprovincialis. For this, the toxicity was assessed after a short-term exposure (14 days) to an environmentally relevant concentration of each element (10 μg/L), followed by a recovery period (14 days) in the absence of any contaminant. The measured biomarkers included energy-related parameters, activity of antioxidant and biotransformation enzymes, indicators of oxidative damage, levels of oxidized glutathione and neurotoxicity. After exposure mussels accumulated more La (0.54 μg/g) than Gd (0.15 μg/g). After recovery higher concentration decrease was observed for Gd (≈40% loss) compared to La exposed mussels (≈30% loss) which may be associated with lower detoxification capacity of mussels previously exposed to La. Mussels increased their metabolism (i.e., higher electron transport system activity) only after the exposure to Gd. Exposure to La and Gd resulted into lower energy expenditure, while when both elements were removed glycogen and protein concentrations decreased to values observed in non-contaminated mussels. Antioxidant and biotransformation capacity was mainly increased in the presence of Gd. This defense response avoided the occurrence of cellular damage but still loss of redox balance was found regardless the contaminant, which was re-established after the recovery period. Neurotoxicity was only observed in the presence of Gd with no effects after the recovery period. Results showed that a short-term exposure to La and especially to Gd can exert deleterious effects that may compromise specific biochemical pathways in aquatic species, such as M. galloprovincialis, but under low concentrations organisms can be able to re-establish their biochemical status to control levels after a recovery period.

Risk of Collapse in Water Quality in the Guandu River (Rio de Janeiro, Brazil)

The Guandu River, one of the main rivers in the state of Rio de Janeiro, provides water for more than nine million people in the metropolitan region. However, the Guandu has suffered from massive domestic and industrial pollution for more than two decades, leading to high levels of dissolved total phosphorus, cyanobacteria, and enteric bacteria observed during the summers of 2020 and 2021. The use of Phoslock, a palliative compound, was not effective in mitigating the levels of phosphorus in the Guandu River. Furthermore, potable water driven from the river had levels of 2-MIB/geosmin and a mud smell/taste. With all these problems, several solutions are proposed for improving the Guandu River water quality, including establishment of (i) sewage treatment plants (STPs), (ii) strict water quality monitoring, (iii) environmental recovery (e.g., reforestation), and (iv) permanent protected areas. The objective of this paper is to verify the poor water quality in the Guandu and the ineffectiveness and undesired effects of Phoslock.

Preliminary assessment of health risks associated with consumption of grapevines contaminated with mining effluents in Turkey: Persistent trace elements and critical raw materials

In this study, some persistent trace elements and critical raw materials were investigated in grapevines contaminated with Pb-Zn mining effluents. The persistent trace elements under certain conditions remain without any change in form in the environment over long periods. The critical raw materials are the ones that have economic importance and have the risks associated with their supply. The health risks of persistent trace elements and critical raw materials in the leaves of grapevine that are consumed by humans were determined. The highest persistent trace elements concentrations followed the order of root > stem > leaf for Mn, Cu, Cd, Ni, and Cr while root > leaf > stem for Zn and leaf > root > stem for Pb. The maximum critical raw material concentrations for Co and V followed the order of root > stem > leaf. For Sb and La, these were leaf > root > stem and root > stem > leaf, respectively. The maximum critical raw materials concentrations for W was leaf > stem = root. The total maximum carcinogenic value was 0.146 for Cd while the total minimum carcinogenic value was 0.0054 for Pb. In this study, potential carcinogenic risk values in terms of ingestion of contaminated soil (Cr, Cd, and Ni) and dietary take of grapevine leaves (Ni, Cr, Cd, and Pb) are higher than acceptable levels (1 × 10^-4  - 1 × 10^-6 ). Maximum cancer risk on human health was determined as dietary intake of grapevine leaves. When hazard quotient for dietary (HQ_die ), hazard quotient for ingestion (HQ_ing ), and hazard quotient for inhalation (HQ_inh ) values ​​of critical raw materials were examined, the maximum values ​​were observed for children. Also, the highest hazard quotient for dermal (HQ_der ) value was determined for men. The hazard index and total hazard index values were >1 for critical raw materials. As a result, values >1 indicated potential non-carcinogenic human health risk associated with the consumption of grapevines contaminated with mining effluents. Actual region-specific exposure estimates for consumption of grapevines, however, were not evaluated. Integr Environ Assess Manag 2022;18:517-527. © 2021 SETAC.

How temperature rise will influence the toxic impacts of 17 α-ethinylestradiol in Mytilus galloprovincialis?

Pharmaceutical drugs are Contaminants of Emerging Concern (CECs) and are continuously discharged into the environment. As a result of human and veterinary use, these substances are reaching aquatic coastal systems, with limited information regarding the toxic effects of these compounds towards inhabiting organisms. Among CECs are pharmaceuticals like 17 α-ethinylestradiol (EE2), which is a synthetic hormone with high estrogenic potency. EE2 has been increasingly found in different aquatic systems but few studies addressed its potential toxicity to marine wildlife, in particular to bivalves. Therefore, the aim of the present study was to evaluate the influence of temperature (17 °C-control and 21 °C) on the potential effects of EE2 on the mussel Mytilus galloprovincialis. For this purpose, mussels were exposed to different concentrations of EE2 (5.0; 25.0; 125.0 and 625 ng/L), resembling low to highly polluted sites. Mussels exposed to each concentration were maintained under two temperatures, 17 and 21 °C, which represent actual and predicted warming conditions, respectively. After 28 days, oxidative stress status, metabolism related parameters, neurotoxicity and histopathological alterations were measured. The results obtained clearly showed an interactive effect of increased temperature and EE2, with limited antioxidant and biotransformation capacity when both stressors were acting together, leading to higher cellular damage. The combination of both stressors also enhanced mussels' metabolic capacity and neurotoxic effects. Nevertheless, loss of redox balance was confirmed by the strong decrease of the ratio between reduce glutathione (GSH) and oxidized glutathione (GSSG) in contaminated mussels, regardless the temperature. Histopathological indexes in contaminated mussels were significantly different from the control group, indicating impacts in gills and digestive glands of mussels due to EE2, with higher values observed at 21 °C. Overall, this study demonstrates that of EE2 represents a threat to mussels and predicted warming conditions will enhance the impacts, which in a near future might result in impairments at the population and community levels.

Rare earth elements biomonitoring using the mussel Mytilus galloprovincialis in the Portuguese coast: Seasonal variations

Increased Rare earth elements (REE) usage culminates in discharges into the environment. Mussels have been chosen as models in biomonitoring, hence, REE concentrations in Mytilus galloprovincialis from six locations on the Portuguese coast were accessed to determine natural concentrations and possible linkage to local ecosystem characteristics and temporal variations, by determining them in distinct seasons (autumn and spring). Samples from Porto Brandão (located on the south bank of the Tagus estuary) exhibited the highest REE concentrations, while mussels from Aljezur (the southernmost point on the Portuguese coast) exhibited the lowest, in both seasons. Overall, ∑REE concentration was greater in the spring. LREE enrichment relative to HREE occurs and a negative Ce and Eu anomaly was observed. This study constitutes the first assessment of REE composition on this model species in the Portuguese coast, in two distinct seasons and contributes to a better understanding of REE uptake for future biomonitoring studies.

Assessment of heavy metal accumulations and health risk potentials in tomatoes grown in the discharge area of a municipal wastewater treatment plant

Some heavy metals were detected in organs of the tomatoes grown in the discharge area of effluents of a municipal wastewater treatment plant. Also, the health risk potentials of heavy metals in the tomatoes consumed by human were investigated. The highest concentrations for Cu, Ni, Cr, Mn and Pb were followed the order of root>leaf>stem>fruit. When the bioconcentration factors values calculated for bioconcentration of metals from effluent to stem and root were examined, the highest values were determined for Cu. When translocation factors values are examined, the highest translocation from root to leaf was determined for Cd. The highest translocation from stem to leaf was determined for Pb. The estimated total exposure dose for male, female and children was listed as Zn>Mn>Cu>Cr>Ni>Pb>Cd. In terms of dietary, we can list the non-carcinogenic risks of heavy metals as children> female> male. The highest carcinogenic risk was calculated for Cr via dietary intake.

Will climate changes enhance the impacts of e-waste in aquatic systems?

The increase of the worlds' population is being accompanied by the exponential growth in waste of electrical and electronic equipment (e-waste) generation as a result of the rapid technological implementations. The inappropriate processing and disposal of this e-waste, containing rare-earth elements (REEs) such as gadolinium (Gd), may enhance its occurrence in the environment. In particular, the presence of Gd in marine systems may lead to environmental risks which are still unknown, especially considering foreseen climate modifications such as water salinity shifts due to extreme weather events. Within this context, the present study intended to assess the combined effects of Gd at variable salinities. For that, biochemical modifications were assessed in mussels, Mytilus galloprovincialis, exposed to Gd (0 and 10 μg/L) and different salinity levels (20, 30 and 40), acting individually and in combination. A decrease in salinity, induced an array of biochemical effects associated to hypotonic stress in non-contaminated and contaminated mussels, including metabolism, antioxidant and biotransformation defenses activation. Moreover, in Gd-contaminated organisms, the increase in salinity was responsible for a significant reduction of metabolic and defense mechanisms, possibly associated with a mussels' physiological response to the stress caused by the combination of both factors. In particular, Gd caused cellular damage at all salinities, but mussels adopted different strategies under each salinity to limit the extent of oxidative stress. That is, an increase in metabolism was associated to hypotonic stress and Gd exposure, an activation of defense enzymes was revealed at the control salinity (30) and a decrease in metabolism and non-activation of defenses, associated with a possible physiological defense trait, was evidenced at the highest salinity. The different strategies adopted highlight the need to investigate the risk of emerging contaminants such as REEs at present and forecasted climate change scenarios, thus providing a more realistic environmental risk assessment.