Research progress on the pollution status and their detection methods of microplastics in aquatic products

As an emerging pollutant， microplastics have become a significant component of global environmental pollution， thereby attracting growing attention from the scientific community and policymakers. Microplastics， defined as plastic particles smaller than 5 mm in diameter， are widely distributed in aquatic environments， including rivers， lakes， oceans， and even groundwater. Due to their small size and persistent nature， microplastics can be easily ingested by aquatic organisms， particularly shellfish， crustaceans， and fish， which are integral components of the aquatic food web. These aquatic products serve as a crucial source of animal protein for human consumption， making the contamination of microplastics in these organisms a direct pathway for human exposure. Once ingested， microplastics may accumulate in human tissues and organs， potentially causing irreversible harm to human health， including inflammatory responses， oxidative stress， and even carcinogenic effects. Therefore， understanding the contamination， distribution， and ecological impacts of microplastics in aquatic products is of paramount importance for both environmental protection and public health. This paper provides a comprehensive review of the current state of microplastic pollution in aquatic products， focusing on the primary sources， pollution pathways， distribution patterns， and ecological consequences. Microplastics enter aquatic environments through various routes， including the breakdown of larger plastic debris， industrial effluents， wastewater treatment plants， and agricultural runoff. Once in the water， microplastics can be ingested by aquatic organisms， either directly or indirectly through the consumption of contaminated prey. The accumulation of microplastics in aquatic organisms not only affects their growth， reproduction， and survival but also disrupts the balance of aquatic ecosystems. Furthermore， microplastics can act as carriers for other pollutants， such as heavy metals and persistent organic pollutants， exacerbating their toxic effects on aquatic life and humans. In addition to analyzing the sources and ecological impacts of microplastic pollution， this paper critically evaluates the technical progress in microplastic extraction and identification methods. Current techniques for microplastic detection include visual identification， spectroscopic methods（e.g.， Fourier-transform infrared spectroscopy（FT-IR） and Raman spectroscopy， and chromatographic-mass spectrometric approaches（e.g.， pyrolysis-gas chromatography-mass spectrometry（Py-GC-MS））. Each method has its advantages and limitations. For instance， visual identification is simple and cost-effective but lacks accuracy for small-sized particles， while spectroscopic methods offer high specificity and sensitivity but require expensive equipment and specialized expertise. Chromatographic-mass spectrometric techniques provide detailed chemical composition analysis but are often time-consuming and complex. This paper discusses the strengths and weaknesses of these methods， highlighting the need for standardized protocols to improve the comparability and reliability of microplastic detection data. Looking ahead， this paper prospects the future directions of microplastic identification and detection technologies in aquatic products. Emerging techniques， such as nanomaterial-based sensors， surface-enhanced Raman scattering（SERS）， and machine learning-assisted image analysis， hold great promise for enhancing the sensitivity， accuracy， and efficiency of microplastic detection. Moreover， the integration of multiple detection methods， such as combining spectroscopic and chromatographic techniques， could provide a more comprehensive understanding of microplastic contamination. The development of low-cost， portable detection devices is also essential for enabling widespread monitoring and real-time assessment of microplastic pollution in aquatic environments. Finally， this paper addresses the challenges and potential prevention and control measures in microplastic research. Key challenges include the lack of standardized detection methods， difficulties in detecting small microplastics or nanoplastics， and limited knowledge of their long-term ecological and health impacts. To tackle these issues， interdisciplinary collaboration among scientists， policymakers， and industry stakeholders is crucial. Potential prevention and control measures include reducing plastic waste at the source， improving wastewater treatment technologies， and promoting public awareness of plastic pollution. By summarizing existing research findings， this paper aims to provide a theoretical foundation and technical support for the risk assessment of microplastic contamination in aquatic products and the development of effective monitoring and management strategies. The insights gained from this review will contribute to safeguarding aquatic ecosystems， ensuring the safety of aquatic products， and protecting human health from the adverse effects of microplastic pollution.