# Microplastics in Water Resources: Threats and Challenges
## 6 Summary  
The development of plastic production has led to a significant increase in plastic waste, which is now a global environmental issue. The presence of microplastics (MPs) has been confirmed in all environmental components. They can accumulate in soil, sediment, and within plant, animal, and human organisms, posing serious threats. MPs travel through the environment via air, rivers, and ocean currents, contaminating even remote areas far from emission sources. Their presence in freshwater and marine environments can lead to the release of many hazardous chemicals, which can threaten the health of aquatic organisms and humans. Additionally, MPs have the ability to adsorb toxic substances, facilitatingtheir transport along the food chain and bioaccumulation. The presence of MPs in surface and groundwater also poses significant challenges for drinking water treatment processes. In recent years, there has been a significant increase in interest in MPs in the environment, resulting in the dynamic development of analytical methods. These methods include optical microscopy, FTIR, fluorescence microscopy, and the relatively new LDIR method. Each of these methods has certain advantages and limitations. Optical microscopy is quick and simple, but has limitations in identifying the chemical composition of MPs and can lead to errors. FTIR allows for precise identification of the types of plastic and chemical additives but requires complicated sample preparation and has difficulties analyzing very small particles. Fluorescence microscopy is a quick and less expensive method, but it has difficulties in unequivocally identifying the plastic and may confuse MPs with other materials. LDIR is a modern technique that offers fast and automated quantitative and qualitative analyses with a low risk of errors, although it requires complicated sample preparation, the use of relatively expensive filters, and may have difficulty identifying adjacent particles. These limitations highlight the need for a more integrated approach to MP analysis, where the choice of method is tailored to the specific characteristics of the MPs in question. For example, combining LDIR with advanced image processing algorithms could mitigate the adjacency issue, while coupling FTIR with complementary techniques such as Raman spectroscopy could improve the detection of small particles. Obtaining reliable results with each of the aforementioned methods is mainly dependent on proper sample preparation for analysis. MPs are often difficult to distinguish from other microparticles, such as plant fibers or zooplankton, present in environmental samples, making proper separation and extraction of MPs from samples crucial. Mechanical, chemical, and physical methods such as sieving, density separation, foam flotation, or oil phase extraction are used for this purpose. Chemical and enzymatic methods are also used to dissolve organic matter. Each of these methods has its applications and limitations, and the appropriate choice depends on the type of sample and the specific analytical requirements. In conclusion, researchers dealing with MPs still face many challenges. There is still a need to develop effective methods for identifying MPs, particularly to address the interplay between MP characteristics and analytical limitations. Future research should focus on developing standardized protocols that account for the diversity of MP sizes and shapes, as well as integrating multiple analytical techniques to overcome individual method limitations. Consistent terminology and methods for describing detected micro- and nanoplastics also need to be established. Therefore, effectively managing the microplastics problem in the environment requires a comprehensive approach based on interdisciplinary scientific collaboration and practical actions at local, national, and international levels.