Abstract: The micro(nano)plastics (MNPs) pollution has emerged as an increasingly prominent global marine ecological and environmental challenge, attracting wide concerns. MNPs can enter marine organisms via respiration and ingestion, and transfer within food chains, which potentially poses long-term risks to marine ecosystems. Crabs are key species in marine ecosystems, playing a crucial role in maintaining ecological balance and serving as an indispensable protein source for humans. As marine MNPs pollution increases, large quantities of MNPs have been detected in marine crabs, posing potential threats to both marine ecosystems and human health. Therefore, identi-fying the occurrence levels of MNPs in crabs is critically important. We reviewed the separation, enrichment, and detection of MNPs in marine crabs, and found that alkaline digestion using potassium hydroxide is an efficient method for digesting soft tissue to extract and enrich MNPs. We then summarized the occurrence levels and distribution of MNPs in marine crabs, and found that MNPs primarily accumulate in gills, blood, stomach, intestine, and hepatopancreas. Additionally, MNPs could transport from blood to other tissues and organs including the brain. The environmental concentration, material composition, shape, particle size, and color of MNPs are the primary factors influencing their accumulation in marine crabs. Polyethylene, polyethylene terephthalate, and polypropylene are the most abundant types in marine crabs. The amounts of small-sized and fiber-shaped MNPs are more abundant than other types of MNPs in marine crabs. Furthermore, we clarified the toxic effects and mechanisms of MNPs on marine crabs, including developmental retardation, increased mortality, and tissue oxidative stress, elucidated potential human health risks posed by MNPs entering the human body through the food chain, such as cell apoptosis, tissue damage, and metabolic disorders. Finally, we outlined future research priorities: enhancing detection efficiency for MNPs in marine crabs, examining their adverse impacts under authentic environmental conditions, and refining ecological risk assessment models for MNPs in marine organisms.

Key words: marine crab, micro(nano)plastics, separation and enrichment, occurrence level, food chain, toxicity