Ecotoxico-lipidomics in fish under field conditions: a systematic review of lipid-based responses to environmental contamination

Aquatic organisms are continuously exposed to complex mixtures of environmental contaminants, making it challenging to link exposure to biological effects under realistic conditions. Lipids play central roles in energy metabolism, membrane structure, and cellular signaling, and can act as integrative indicators of environmental stress. Lipidomics has emerged as a powerful tool to capture integrated metabolic responses, supporting the development of ecotoxico-lipidomics as an emerging framework linking environmental exposure to lipid-mediated effects. This study aimed to systematically review lipid-based responses in fish under field conditions and identify consistent patterns across analytical approaches. A systematic literature review was conducted using a structured PECO framework. Searches were performed in Web of Science, PubMed, ScienceDirect, and Wiley Online Library using keywords related to lipidomics, fish, and contamination (last updated in April 2026). Studies were included if they assessed lipid profiles (fatty acids, lipid classes, or molecular species) in wild-caught or in situ exposed fish and examined associations with environmental contamination. Following screening and eligibility assessment, 25 studies were included. Most studies (84%) employed targeted approaches, primarily focusing on fatty acids or bulk lipid classes, whereas only a few applied untargeted lipidomics. Consistent patterns across studies included reductions in long-chain polyunsaturated fatty acids and increases in saturated and monounsaturated fatty acids, along with alterations in membrane and storage lipids. These responses were associated with metals, persistent organic pollutants, and wastewater-derived compounds. Most studies provided associative or functional interpretations, while mechanistic insights remained limited. Nevertheless, these patterns can be interpreted within an ecotoxico-lipidomics perspective. Lipid-based approaches provide robust insights into the effects of environmental contamination in fish under field conditions, but current evidence is dominated by targeted strategies with limited molecular resolution. Integrating untargeted lipidomics with exposomic and multi-omics data will be essential to advance ecotoxico-lipidomics as an emerging comprehensive and integrative approach.