Publicação
Ecotoxicological impacts induced by emerging pollutants in marine species exposed to different climate change scenarios
| Resumo: | Population growth, industrial expansion and transition to green energy have driven the increasing use of Rare Earth Elements (REEs). The unique properties of these elements have made them indispensable in high-tech applications, green energy technologies, electronics, medicine, agriculture, and military defence systems. The growing importance of REEs has contributed to their increased extraction and processing, resulting in higher amounts of these elements in aquatic systems. Although widely used, REEs remain unregulated, scarcely monitored, and poorly understood in terms of toxicity. Among REEs, praseodymium (Pr), neodymium (Nd), europium (Eu), and dysprosium (Dy) present different levels of supply risk and economic importance, as well as distinct roles in a wide range of applications. Aquatic systems face threats not only from contamination but also from climate change (CC)-related factors, like warming and salinity shifts. The main contributor to warming is carbon dioxide emission, while changes in global rainfall and evaporation cycles may cause salinity shifts. The intensity and frequency of these CC-related factors have been increasing, and their detrimental impacts on several aquatic organisms have already been documented. However, the impacts resulting from the interaction between CC-related factors and contamination by REEs remain poorly understood. Therefore, this thesis aimed to assess the impacts of Pr and Eu on adult mussels of Mytilus galloprovincialis as a starting point. Besides being considered an excellent bioindicator, this species also holds significant ecological and economic relevance. After that, a low and environmentally relevant concentration of these elements, as well as Nd and Dy was selected. Adult mussels and male gametes were exposed to the combination of these elements with increasing temperature or salinity shifts, to evaluate the influence of these abiotic factors on the impacts of REEs. To achieve these goals, biochemical (energy balance, defence system, cellular damage) and histopathological analysis (in gill and digestive gland) were performed in adult mussels after 28 days of exposure, while biochemical (production of reactive oxygen species and cellular damage) and physiological analysis (respiration rate, motility and velocity) were evaluated in male gametes after 30 min of exposure. The findings revealed that all tested REEs induced significant alterations in adult mussels and sperm under standard conditions. However, elevated temperature and varying salinity levels altered their sensitivity and responses to these elements differently. In particular, while increased temperature had a limited influence on the impacts of Nd and Dy, higher responsiveness was observed in the case of Pr and Eu combined with higher temperature. Low and high salinity levels intensified the sensitivity of this species to the tested REEs, except for a lower salinity combined with Eu exposure. Low salinity induced higher responsiveness than high salinity when combined with Nd and Dy, while the opposite was observed in the exposure of Eu. For Pr, the overall influence of low and high salinity was comparable. This thesis explores the potential impacts of REEs contamination on reproductive success and This thesis explores the potential impacts of REEs contamination on an ecologically and economically relevant species, M. galloprovincialis, which could compromise the reproductive success and health of mussels, with possible implications for population dynamics. Furthermore, the results suggest that CC-related factors may modulate the impacts of REEs on this species. However, the combination of different REEs with CC-related factors revealed that mussels and their male gametes may adopt different strategies depending on the element and the climatic factor, illustrating the complex interactions resulting from the possible combinations and emphasizing the need for further investigation in this area. This thesis provides essential insights for policymakers, highlighting the potential risks associated with REE contamination and the importance of establishing regulatory restrictions to mitigate their environmental impacts. |
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| Autores principais: | Leite, Carla Patrícia da Silva |
| Assunto: | Rare earth elements Climate change Ecotoxicology Bivalves Adults health Sperm quality |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | Population growth, industrial expansion and transition to green energy have driven the increasing use of Rare Earth Elements (REEs). The unique properties of these elements have made them indispensable in high-tech applications, green energy technologies, electronics, medicine, agriculture, and military defence systems. The growing importance of REEs has contributed to their increased extraction and processing, resulting in higher amounts of these elements in aquatic systems. Although widely used, REEs remain unregulated, scarcely monitored, and poorly understood in terms of toxicity. Among REEs, praseodymium (Pr), neodymium (Nd), europium (Eu), and dysprosium (Dy) present different levels of supply risk and economic importance, as well as distinct roles in a wide range of applications. Aquatic systems face threats not only from contamination but also from climate change (CC)-related factors, like warming and salinity shifts. The main contributor to warming is carbon dioxide emission, while changes in global rainfall and evaporation cycles may cause salinity shifts. The intensity and frequency of these CC-related factors have been increasing, and their detrimental impacts on several aquatic organisms have already been documented. However, the impacts resulting from the interaction between CC-related factors and contamination by REEs remain poorly understood. Therefore, this thesis aimed to assess the impacts of Pr and Eu on adult mussels of Mytilus galloprovincialis as a starting point. Besides being considered an excellent bioindicator, this species also holds significant ecological and economic relevance. After that, a low and environmentally relevant concentration of these elements, as well as Nd and Dy was selected. Adult mussels and male gametes were exposed to the combination of these elements with increasing temperature or salinity shifts, to evaluate the influence of these abiotic factors on the impacts of REEs. To achieve these goals, biochemical (energy balance, defence system, cellular damage) and histopathological analysis (in gill and digestive gland) were performed in adult mussels after 28 days of exposure, while biochemical (production of reactive oxygen species and cellular damage) and physiological analysis (respiration rate, motility and velocity) were evaluated in male gametes after 30 min of exposure. The findings revealed that all tested REEs induced significant alterations in adult mussels and sperm under standard conditions. However, elevated temperature and varying salinity levels altered their sensitivity and responses to these elements differently. In particular, while increased temperature had a limited influence on the impacts of Nd and Dy, higher responsiveness was observed in the case of Pr and Eu combined with higher temperature. Low and high salinity levels intensified the sensitivity of this species to the tested REEs, except for a lower salinity combined with Eu exposure. Low salinity induced higher responsiveness than high salinity when combined with Nd and Dy, while the opposite was observed in the exposure of Eu. For Pr, the overall influence of low and high salinity was comparable. This thesis explores the potential impacts of REEs contamination on reproductive success and This thesis explores the potential impacts of REEs contamination on an ecologically and economically relevant species, M. galloprovincialis, which could compromise the reproductive success and health of mussels, with possible implications for population dynamics. Furthermore, the results suggest that CC-related factors may modulate the impacts of REEs on this species. However, the combination of different REEs with CC-related factors revealed that mussels and their male gametes may adopt different strategies depending on the element and the climatic factor, illustrating the complex interactions resulting from the possible combinations and emphasizing the need for further investigation in this area. This thesis provides essential insights for policymakers, highlighting the potential risks associated with REE contamination and the importance of establishing regulatory restrictions to mitigate their environmental impacts. |
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