Microplastics have become one of the leading environmental threats due to their persistence, ubiquity and intrinsic toxic potential. The potential harm that microplastics impose on ecosystems varies from direct effects (i.e., entanglement and ingestion) to their ability to sorb a diversity of environmental pollutants (e.g., heavy metals, persistent organic compounds or pharmaceuticals). Therefore, the toxicological assessment of the combined effects of microplastics and sorbed pollutants can produce in biota is one of the hottest topics on the environmental toxicology field. This review aims to clarify the main impacts that this interaction could have on ecosystems by (1) highlighting the principal factors that influence the microplastics sorption capacities; (2) discussing the potential scenarios in which microplastics may have an essential role on the bioaccumulation and transfer of chemicals; and (3) reviewing the recently published studies describing toxicological effects caused by the combination of microplastics and their sorbed chemicals. Finally, a discussion regarding the need for a new generation of toxicological studies is presented.

Microplastic pollution poses a significant environmental threat due to its persistence, widespread distribution, and inherent toxic potential. Despite the increasing number of publications in this field, a standardized protocol for the laboratory intake of microplastics by Daphnia magna has yet to be established. In this study, we introduce a verified protocol designed to facilitate the ingestion of microplastic particles (MPs) by D. magna, ranging in size from 5–55 µm. This protocol can be further applied to evaluate the toxicity of MPs on D. magna, a crucial organism model in ecotoxicology. Furthermore, this protocol can be used to assess toxicity of MPs in other aquatic species, such as fish, by using daphnids as a vehicle for ensuring the ingestion of these particles. Consequently, this protocol can be applied to study also one of the most pressing concerns regarding exposure to MPs, the transfer of MPs through different trophic levels, which has a great potential for ecotoxicological studies. • The influence of MPs concentration, duration and exposure dynamics and D. magna age/size in MPs intake were tested. • We have determined the optimal conditions for promoting microplastic ingestion by D. magna.

Environmental pollutants, particularly endocrine disruptors, are known to significantly dysregulate lipid homeostasis, causing severe health issues. However, their obesogenic effects on invertebrate species, such as the planktonic crustacean Daphnia magna, remain poorly understood. Previous research suggested that compounds such as organotin tributyltin and the insecticide pyriproxyfen promote lipid accumulation, particularly triacylglycerol species. However, bulk LC-MS methodologies used did not retain the spatial context of the biomolecules analyzed, failing in providing crucial insights into the tissue-specific molecular effects of pollutant exposure and risk assessment. The present study evaluates the disruptive effects of these compounds at the lipidomic level using a novel spatial MALDI-MSI-based approach integrated with ion mobility. In terms of toxicological assessment, MALDI-MSI revealed distinct lipidomic disruptions. Both pollutants increased glycerolipids, but glycerophospholipids exhibited opposing patterns. Tributyltin significantly altered the lipid composition of the nervous system, whereas pyriproxyfen predominantly affected the cardiovascular system. In conclusion, the integration of MALDI-MSI with ion mobility not only enhanced the identification of lipids but also allowed to provide deeper insights into the tissue-specific toxicological mechanisms of environmental obesogens in Daphnia magna. Additionally, this study emphasizes the potential of these state-of-the-art analytical techniques in advancing spatial biology and environmental risk assessment.

Tributyltin (TBT) is a persistent environmental contaminant with well-established endocrine-disrupting and obesogenic properties; however, the earliest molecular events linking short-term exposure to functional toxicity remain poorly resolved. In particular, it is unclear whether brief exposure during sensitive developmental windows is sufficient to initiate coordinated molecular programs with downstream neurofunctional consequences. Here, we investigated the effects of a short-term (24 h), environmentally relevant TBT exposure in zebrafish eleutheroembryos by integrating untargeted lipidomics and transcriptomics with neurotransmitter profiling and behavioral assessment. Such exposure was sufficient to disrupt lipid homeostasis, oxidative balance, and neurofunction, suggesting that aquatic organisms are far more sensitive to TBT than previously recognized. This work highlights the value of lipid-centered multi-omics integration for identifying mechanistic pathways affected by endocrine disruptors beyond classical assays. Lipidomics revealed a coordinated reorganization of lipid homeostasis, including depletion of fatty acids, sterols, and glycerophospholipids together with accumulation of glycerolipids, indicating early disruption of lipid metabolic balance. These lipid shifts were supported by transcriptomic reprogramming of lipid-related gene networks, identifying lipid-centered hub genes that explained the observed abundance patterns. Moreover, gene expression dysregulation was consistent with epigenomics and transcriptomics data from longer exposure window (2-5 dpf), underscoring the robustness of early TBT alterations on lipid homeostasis, in addition to other RXR-related processes such as neurotoxicity and signaling disruption. Importantly, lipid-centered molecular alterations were accompanied by disruption of monoaminergic neurotransmitter profiles and transient behavioral impairments, linking early metabolic dysregulation to neurofunctional toxicity. Overall, this study demonstrates that short-term, environmentally relevant TBT exposure is sufficient to initiate lipid-centered molecular programs during early development, with measurable neurochemical and behavioral consequences.

Tributyltin (TBT) is an organotin compound widely recognized for its severe environmental impacts as an endocrine disruptor, particularly for its obesogenic activity. However, its toxic molecular mechanisms remain incompletely understood, especially during early vertebrate development. Novel multi-omics approaches help address this complexity and improve the characterization of pollutants’ mechanisms of action. Here, we applied an integrative multi-omics strategy combining untargeted lipidomics and transcriptomics to characterize short term (24 h) TBT-induced dysregulation in zebrafish eleutheroembryos at environmentally relevant, sublethal concentrations. Such short-term exposure was sufficient to disrupt lipid homeostasis, oxidative balance, and neurofunction, suggesting that aquatic organisms are far more sensitive to TBT than previously recognized. Lipidomics revealed a general depletion of fatty acids, sterols, and glycerophospholipids, together with an accumulation of glycerolipids, consistent with an obesogenic response. These lipid shifts were supported by transcriptomic changes that highlighted lipid-related hub genes explaining the observed abundance patterns. Moreover, gene expression dysregulation was consistent with epigenomics and transcriptomics data from longer exposure window (2–5 dpf), underscoring the robustness of early TBT alterations on lipid homeostasis, in addition to other RXR-related processes such as neurotoxicity and signaling disruption. These molecular alterations were functionally supported by behavioural impairments, and monoaminergic neurotransmitter disruption.This study demonstrate that TBT induces robust and conserved molecular alterations at early developmental stages, even when exposed only for 24h at environmentally relevant concentrations, with key impacts on lipid homeostasis, oxidative balance, and neurofunction. Therefore, this work highlights the potential of lipidomic-guided multi-omics integration approaches for characterizing and identifying mechanistic pathways affected by endocrine disruptors beyond classical assays.