Microplastic Particle Size Research Articles

A new method for analyzing microplastic particle size distribution in marine environmental samples

Microplastics (MPs) are recognized as a global emerging threat to aquatic ecosystems and biodiversity worldwide. Though the number of publications and interest to the MP research have been increased rapidly, it is still hamper to compare the obtained data due to the usage of different methodologies in MP assay. Thus, there is an urgent need for a standardized approach to the procedures of MP quantification in order to produce comparative assessments. In this pilot study, the conventional NOAA protocol of MP extraction from seawater was combined with a simple and inexpensive method for analyzing shape and size spectrum of all MP particles making up the sample. A common flatbed scanner equipped with slide adapter was applied for image acquisition while MP dispersive properties (particle abundance, shape and size spectrum) were quantified using ImageJ software. Feret’s diameter and circularity (or roundness) appeared to be the most efficient shape descriptors for the particle analysis. The total silhouette area of MP particles was shown to produce a confident approximation of the MP overall mass. The first reliable estimates of MP concentrations in the Black Sea coastal waters (Sevastopol Bay) accounted for 0.6 to 7 items m-3 and 6 to750 µg m-3 in terms of abundance and mass, respectively. No steady-state gradients have been revealed in MP distribution along the transect from the mouth of the bay to its corner. Inflow of MP to the bay waters and their transport along the bay seemed to be controlled by a complex combination of factors including rainfalls, wind regimes, currents and the Black river discharge.

Microplastic Pollution of the Beaches in Xiamen Bay, China

Microplastics are tiny ubiquitous plastic particles smaller than five millimeters (5 mm) in size. Coastal and bay areas are constantly under continuous and increasing pressure from the activities of humans. Microplastic pollution is now recognized as a great threat to these areas. This study was designed to understand the microplastic pollution of the beaches in Xiamen Bay. The results showed that microplastic abundance was from (28.1±9.4) to (312.7±35.2) n·kg-1. Four main types of microplastics were identified in Xiamen Bay, including fragments, foams, thin films, and fibers. Of the particles analyzed, over 80% were predominantly microplastic fragments and foam, while the films and fiber microplastics accounted for less than 20% of the particles. Studies on the particle size of microplastics also indicated that the microplastics with particle size less than 1 mm accounted for over 60% of the total microparticles, and the abundance of microplastics trend to decrease with increase in the particle size. Fourier transform infrared spectroscopy analysis demonstrated that the major component of the fragments and fibers was identified as polyethylene, and that of foams and films was identified as polystyrene. The scanning electron microscope studies showed that the microplastics presented obvious signs of cracks. In general, Xiamen Bay beach microplastic pollution is at a lower middle level, and land source pollution is the main source of the microplastic pollution.

Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure

Microplastics (MPs) are a significant environmental health issue and increasingly greater source of concern. MPs have been detected in oceans, rivers, sediments, sewages, soil and even table salts. MPs exposure on marine organisms and humans has been documented, but information about the toxicity of MPs in mammal is limited. Here we used fluorescent and pristine polystyrene microplastics (PS-MPs) particles with two diameters (5 μm and 20 μm) to investigate the tissue distribution, accumulation, and tissue-specific health risk of MPs in mice. Results indicated that MPs accumulated in liver, kidney and gut, with a tissue-accumulation kinetics and distribution pattern that was strongly depended on the MPs particle size. In addition, analyses of multiple biochemical biomarkers and metabolomic profiles suggested that MPs exposure induced disturbance of energy and lipid metabolism as well as oxidative stress. Interestingly, blood biomarkers of neurotoxicity were also altered. Our results uncovered the distribution and accumulation of MPs across mice tissues and revealed significant alteration in several biomarkers that indicate potential toxicity from MPs exposure. Collectively, our data provided new evidence for the adverse consequences of MPs.

Questions of size and numbers in environmental research on microplastics: methodological and conceptual aspects

Environmental context Microplastics, either purposefully manufactured or formed by fragmentation of discarded ‘end-of-life’ macroplastic items, are accumulating in environmental compartments. As more and more data are collected on microplastics in the environment, discussion of two issues has become indispensable: (i) how reliable are the results in terms of the inherent capabilities and limitations of current methods used for sampling, counting and measuring microplastic particles; and (ii) how can the fate of microplastics be understood in the context of natural particles and colloids? Abstract A first important step in evaluating the impact of microplastic pollution in natural systems is assessing the reliability of the results obtained according to the inherent capabilities and limitations of the methods used for sampling, counting and measuring microplastic particles. This study, based on the critical reading of 55 studies containing quantitative microplastic data in waters and sediments, is an attempt to analyse these issues in the light of existing knowledge in the field of natural colloid studies. Existing results are highly dependent on the sampling and methodological procedure chosen and are essentially descriptive. Moreover, often they lack standardisation and adequate reporting of basic information such as the meaning of the size parameter measured. Colloid theory may provide the theoretical background needed to explain microplastic behaviour or, at least, to identify the parameters (e.g. density, surface characteristics, shape) that need to be known in order to gain a predictive knowledge of the subject. They are introduced and discussed. Finally, microplastics are not alone in environmental compartments. For this reason, when possible, published microplastic particle size distributions in natural waters have been quantitatively situated in the context of natural particles.