Linking metabolic state to carbamazepine accumulation in Arctic benthic invertebrates

Pharmaceutical pollutants, such as carbamazepine (CBZ), are increasingly detected in polar marine ecosystems, raising concerns about their bioaccumulation and impact on resident fauna. This study investigated the presence of CBZ and metabolic alterations in two Arctic macrobenthic invertebrates: the suspension-feeding bivalve Ciliatocardium ciliatum and the predatory starfish Urasterias lincki, collected from two fjords of the Svalbard archipelago: Hornsund (77°N) and Kongsfjorden (79°N). Using LC-MS/MS, CBZ was detected exclusively in U. lincki tissues (0.14 ng/g wet weight), while it was absent in C. ciliatum, suggesting species-specific differences in bioaccumulation potential. Importantly, U. lincki exhibited significantly higher tissue lipid content (mainly cholesterol), approximately twice that of bivalves, which likely facilitated the accumulation of lipophilic compounds such as CBZ. Comprehensive metabolic profiling revealed that U. lincki also exhibited higher levels of ATP, glycogen, glutathione, and total antioxidant capacity, indicating a more active oxidative metabolism. In contrast, C. ciliatum showed signatures of metabolic downregulation, including elevated succinate, malate, and purine degradation products, suggesting a reliance on anaerobic pathways and limited detoxification capacity. These findings underscore the role of feeding strategy, lipid content, and oxidative stress regulation in shaping pharmaceutical accumulation in Arctic benthic fauna and highlight the vulnerability of cold-adapted organisms to persistent emerging pollutants in polar ecosystems.