Spatially resolved elemental imaging reveals microdomain-specific trace element accumulation in Patella vulgata under antimony exposure: implications for marine biomonitoring.

Coastal ecosystems are increasingly impacted by anthropogenic contamination, yet conventional biomonitoring approaches based on bulk tissue analysis provide limited insight into the biological processing of pollutants. Here, Patella vulgata was evaluated as a bioindicator using quantitative, spatially resolved multi-element imaging by laser ablation inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOFMS). Distinct accumulation patterns were observed across organs, with the digestive gland identified as the primary compartment for long-term storage of both essential and toxic elements, while gills reflected more direct interaction with the surrounding seawater. High-resolution multi-element mapping revealed pronounced spatial heterogeneity within the digestive gland, indicating functional compartmentalisation associated with elemental uptake, distribution, and potential sequestration processes. Data-driven analysis further resolved microdomains characterised by distinct elemental signatures consistent with tissue microanatomy. Using controlled exposure to antimony (Sb, 2 μg/L) as a model contaminant, representing a high-end but environmentally plausible coastal contamination scenario, selective accumulation was observed exclusively in the digestive gland, with mean concentrations increasing to 0.42 μg/g and localised hotspots reaching 5.3 μg/g. This tissue-specific response demonstrates the ability of P. vulgata to record and spatially resolved elevated Sb exposure patterns and highlights the importance of sub-organismal resolution for interpreting contaminant dynamics. Overall, this work demonstrates that spatially resolved elemental analysis can provide mechanistic hypotheses and complementary information into pollutant uptake and storage, advancing marine biomonitoring beyond bulk measurements. Rather than replacing established monitoring approaches, LA-ICP-TOFMS provides a high-resolution research tool for investigating contaminant localisation and biological responses at the microanatomical scale. The approach establishes P. vulgata as a valuable sentinel species form investigating trace metal behaviour and offers a framework for assessing contaminant distribution in coastal environments.