Bystander effects in ecological risk assessment

• Autor(a) principal: Martins, Diana Castelhano
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/40381
• topic: Ecological Risk Assessment (ERA); Bystander effect; Ecological relevance; Environmental protection and management

In recent years, research on the bystander effect has contributed to the elucidation of the intricate web of ecological consequences stemming from contaminant exposure. This dissertation encompasses a multidisciplinary exploration of bystander signaling mechanisms, molecular pathways, and the transgenerational implications of these effects. T his thesis reinforces the idea that bystander effects are not isolated phenomena but rather pervasive ecological responses to various stressors. As such, they challenge traditional Ecological Risk Assessment ( ERA practices, which may underestimate some ecological risks associated with contaminant exposure. This study documents the molecular underpinnings of bystander effects, highlighting the diverse signaling molecules involved, such as reactive oxygen species (ROS), cytokines, and various pathways like MAPK and NF κB/COX 2. Moreover, it discusses their occurrence in a broad spectrum of biological models, ranging from human cells to animal models, emphasizing their potential long term consequences and the transgenerational propagation of stress responses. Findings disclose that contaminants' influences can extend be yond directly exposed organisms, potentially affecting non target species, community dynamics, and ecosystem functions. The integration of bystander effects into ERA is suggested , acknowledging the ecological complexities that emerge in real world ecosystems. The outlin ing of potential benefits of such integration is made , such as better risk predictions, the detection of subtle or indirect impacts, and enhanced expert judgment in environmental management. However, this integration poses significant difficulties and limitations, including the complexity and variability of bystander mechanisms, data gaps, regulatory framework challenges, and resource and expertise requirements. This study envisions the future direction of bystander effect studies, calling for the use of advanced techniques, like omics technologies, for deeper insights. It emphasizes the importance of studying the interplay between bystander effects and multiple stressors in the environment and advocates for a closer collaboration between scientists, policymakers, and regulatory agencies to bridge the gap between research and policy im plementation. In conclusion, this work not only expands our understanding of bystander effects but also advocates for their incorporation into ERA. This endeavor promises more accurate, sensitive, and ecologically relevant risk assessments, ensuring the protection of populations and entire ecosystems.