Microplastics, Volume 2, Issue 3 (September 2023) – 8 articles

Environmental pollution by microplastics (MPs) has become a growing concern, and not only professional researchers but also the citizenry are needed to understand the pollution situation and to confirm the decreasing trend of MP pollution as a result of the global reduction in plastic use. In this study, the author evaluated the accuracy of a simple method of investigating MPs on sandy beaches that can be conducted even by high school students. In a land survey using simple tools such as a tape measure and cardboard, the maximum coefficient of variation is approximately 1%. Even without heavy liquid, 89% of MPs could be recovered using only seawater. An investigation of MP content by sampling 0.5 cm of the surface layer of sand could explain more than half of the MP content when the sand was sampled to a depth of approximately 50 cm below the surface layer. A method in which the recovered MPs are not visually sorted but floating matter after boiling is considered as MPs is acceptable. If there was no concern about pumice contamination, the overestimation was approximately 1.5 times. Simple laboratory equipment such as buckets, sieves, seawater, hot plates, dryers, and electronic balances could achieve lower limits of quantification of MPs of 13 mg-MPs/m²-sand and 2 mg-MPs/kg-sand. Full article

Microplastic pollution has become a global environmental concern with detrimental effects on ecosystems and human health. Effective removal of microplastics from water sources is crucial to mitigate their impacts. Advanced oxidative processes (AOPs) have emerged as promising strategies for the degradation and elimination of microplastics. This review provides a comprehensive overview of the application of AOPs in the removal of microplastics from water. Various AOPs, such as photocatalysis, ozonation, and Fenton-like processes, have shown significant potential for microplastic degradation. These processes generate highly reactive species, such as hydroxyl radicals, which can break down microplastics into smaller fragments or even mineralize them into harmless byproducts. The efficiency of photocatalytic oxidation depends on several factors, including the choice of photocatalysts, reaction conditions, and the physicochemical properties of microplastics. Furthermore, this review discusses the challenges associated with photocatalytic oxidation, such as the need for optimization of operating parameters and the potential formation of harmful byproducts. Overall, photocatalytic oxidation offers a promising avenue for the removal of microplastics from water, contributing to the preservation of aquatic ecosystems and safeguarding human health. However, further research is needed to address the limitations and optimize the implementation of this process for effective and sustainable microplastic remediation. Full article

When plastics are discarded, they do not biodegrade and instead break down over time into progressively smaller particles, termed secondary microplastics, which adversely impact biota and human health as well as persist in the environment for centuries. Our research objective was to evaluate the capabilities of object-based image analyses in detecting compositionally varied microplastics suspended in an aquatic mesocosm under no-slip and turbulent water conditions. We found that the presence of polypropylene, polyethylene terephthalate, and low-density polyethylene microplastic pollution in both single-type and mixed-type suspensions was not detectable by either average red (R), average blue (B), average green (G), or average RBG pixel intensities, but was significantly detectable by means of total RBG pixel intensity from digital imagery of the surface-water. Our findings suggest that object-based image analyses of surface waters to quantify pixel information is better suited for monitoring the presence and absence of suspended microplastics, rather than for the stepwise determination of microplastic concentrations. We propose the development of a smartphone application to facilitate citizen-science monitoring of microplastic contamination as well as comment on future applications utilizing drone imagery to boost cloud-based mapping spatiotemporal plumes. Full article

Wetlands are being contaminated by housing developments, effluents, industrial areas, and poor sanitation, resulting in the presence of plastic polymers and the development of biofilms on these materials, which represent an elevated risk to freshwater fauna and flora. The objective of this study was to characterize mesoplastics and microplastics, collected in the Gualí Wetland, Colombia, as well as to verify the presence of biofilms on such polymers. Nine water samples (36 L per sample) were evaluated at three points of the wetland; the size of the particles was determined by image analysis, the type of polymer through FTIR, and the presence of biofilms by microscopy. A total of 79 items/0.135 m³ were collected, 2 macroplastic items, 53 mesoplastic items, and 24 microplastic items. The presence of fragments (70%) and pellets (41%), with transparent (40%) and white (30%) being the predominant ones, was outstanding. Among the polymers, high-density polyethylene (HDPE) dominated, followed by expanded polystyrene. The results of SEM demonstrated the presence of diatoms on the surface of the plastic polymers. Furthermore, the results showed a greater amount of HDPE mesoplastics and microplastics in the shape of fragments and pellets. In addition, the presence of biofilms on these plastic particles can increase the adsorption of contaminants, negatively affecting this ecosystem. The outcome of this study can be used to identify bacteria that reside in biofilms associated with microplastics and mesoplastics. Full article

Microplastics’ presence in the pelagic environment is still largely unknown due to the difficulty of sampling in this part of the ocean. In this study, we quantify microplastics’ exposure in a pelagic lanternfish species from the western Mediterranean, Lampanyctus crocodilus (Risso 1810), which occupies an intermediate position in the marine food web. L. crocodilus were captured in the Ibiza Channel by a trawling vessel and microplastics were extracted by digestion of their gastrointestinal systems. Almost half of the analysed lanternfish contained microplastics, mostly blue and black fibres (40.9% and 34.66%, respectively). In fishes with at least one microplastic, the median was 3 MPs/fish (CI 95% = 3.46–6.8), similar to other studies performed in other fish species in the area. Biometric parameters of fish, such as total length and body condition, were not correlated with the number of microplastics. Data presented here contribute to quantifying the severity of microplastic pollution in the pelagic environment and in a wild, non-commercial species. Full article

The low cost of production and the widespread use of plastics has brought about a problem that is difficult to measure; microplastics are considered emerging pollutants because their presence can pose a risk to the environment. This study focuses on the characterization of microplastics (MPs) in the nesting area of green (Chelonia mydas) and Kemp’s ridley (Lepidochelys kempii) sea turtles, on the coastal municipalities of Nautla and Vega de Alatorre, Veracruz, Mexico. Five beaches along 15.5 km of coastline were analyzed and samples were taken in the intertidal zone. In this work, only microplastics in sizes from one to five mm were analyzed. A characterization of the potential sources of microplastics at the basin level was carried out and 94% of the samples analyzed presented MPs, the greatest amount was at site Playa Navarro (B32) (1.2 Item/kg dw), and in the high tide zone (4.86 ± 2.79 Item/kg dw). The predominant color of the MPs was white (42%), the most representative form were fragments (31%), while most of the MPs presented sizes of 4–5 mm (35%) followed by 1–2 mm (34%). The chemical composition of most of the MPs was polyethylene (55%). Regarding the sources of the MPs generation, livestock, agriculture, fishing, tourism, wastewater discharges, urban solid waste and, to a lesser extent, the plastic industry were identified. The mobilization factors of the MPs turned out to be the Colipa and Misantla rivers with runoff from the basin, wind, waves and marine currents. Full article

Microplastic pollution has become an increasing danger to marine wildlife and ecosystems worldwide. The continued increase in the production of plastic products has caused microplastic pollution to become more distributed, especially along shorelines. Therefore, to better assess the pervasiveness of microplastics around the Pacific Islands, in this work, we conducted a preliminary investigation into the pervasiveness of microplastics along eight different North and South Pacific Island beaches located in New Zealand and Hawaii. Microplastic prevalence was investigated as a function of beach location, sand type, and microplastic type. Our analysis found that all eight locations contained some level of microplastics, and sheltered fine-grained sand beaches contained the highest level of microplastics, with the largest particle size distribution. In addition, spectroscopy analysis was conducted to assess the plastic type, which showed that nylon and polypropylene were the most common types of microplastics among the tested samples. The results of this study offer a preliminary insight into the microplastic accumulation among different beaches, indicating that sheltered fine-grained beaches and ecosystems may be more susceptible to microplastic accumulation. Full article