Tissue distribution of ultraviolet absorbents and industrial antioxidants in Atlantic walruses (Odobenus rosmarus rosmarus) and ringed seals (Pusa hispida) from the Canadian Arctic: Influence of sex, body size, and spatial variation

Abstract

UV absorbents and industrial antioxidants are contaminants of emerging concern. However, their tissue distribution in marine mammals remains poorly characterized. This study investigated the tissue distribution of benzotriazole UV stabilizers (BZT-UVs), organic UV filters (UVFs), 2,6-di-tert-butylphenol (26DTBP), and aromatic secondary amines (Ar-SAs) in Atlantic walrus (Odobenus rosmarus rosmarus) (blubber, muscle, and liver) and ringed seal (Pusa hispida) (blubber and liver) tissues collected around several communities in the Canadian Arctic. In both species, blubber accumulated higher levels of BZT-UVs than other tissues, whereas some UVFs, such as benzophenone and 2-hydroxy-4-methoxybenzophenone (BP3), accumulated more in the muscle or liver of walruses. ∑BZT-UVs in male walrus blubber correlated positively with body length, demonstrating a bioaccumulation trend as individuals grew larger. This contrasts with the evidence of growth dilution observed for ∑UVFs in male walrus liver, and for BP3 and 26DTBP in female ringed seal blubber. Both species exhibited spatial variation in UV absorbent concentrations. This study provides the first data on the tissue distribution of these contaminants in Arctic marine mammals, revealing tissue-, spatial-, sex-, and compound-specific distribution patterns. The findings offer current reference data to support environmental monitoring, risk assessment, and management efforts, particularly for species important to northern Indigenous communities.