Fragmented or otherwise miniaturized plastic materials in the form of micro- or nanoplastics have been of nagging environmental concern. Perturbation of organismal physiology and behavior by micro- and nanoplastics have been widely documented for marine invertebrates. Some of these effects are also manifested by larger marine vertebrates such as fishes. More recently, possible effects of micro- and nanoplastics on mammalian gut microbiota as well as host cellular and metabolic toxicity have been reported in mouse models. Human exposure to micro- and nanoplastics occurs largely through ingestion, as these are found in food or derived from food packaging, but also in a less well-defined manner though inhalation. The pathophysiological consequences of acute and chronic micro- and nanoplastics exposure in the mammalian system, particularly humans, are yet unclear. In this review, we focus on the recent findings related to the potential toxicity and detrimental effects of micro- and nanoplastics as demonstrated in mouse models as well as human cell lines. The prevailing data suggest that micro- and nanoplastics accumulation in mammalian and human tissues would likely have negative, yet unclear long-term consequences. There is a need for cellular and systemic toxicity due to micro- and nanoplastics to be better illuminated, and the underlying mechanisms defined by further work.

Toxicity of Microplastics and Nanoplastics in Mammalian Systems

We report for the first time the ingestion of microplastics by scleractinian corals, and the presence of microplastics in coral reef waters adjacent to inshore reefs on Australia’s Great Barrier Reef (GRE, 18°31′S 146°23′E). Analysis of samples from sub-surface plankton tows conducted in close proximity to inshore reefs on the central GBR revealed microplastics, similar to those used in marine paints and fishing floats, were present in low concentrations at all water sampling locations. Experimental feeding trials revealed that corals mistake microplastics for prey and can consume up to ~50 μg plastic cm−2 h−1, rates similar to their consumption of plankton and Artemia nauplii in experimental feeding assays. Ingested microplastics were found wrapped in mesenterial tissue within the coral gut cavity, suggesting that ingestion of high concentrations of microplastic debris could potentially impair the health of corals.

Microplastic ingestion by scleractinian corals

Microplastics, which are plastic debris with a particle diameter of less than 5 mm, have attracted growing attention in recent years. Its widespread distributions in a variety of habitats have urged scientists to understand deeper regarding their potential impact on the marine living resources. Most studies on microplastics hitherto are focused on the marine environment, and research on risk assessment methodology is still limited. To understand the distribution of microplastics in urban rivers, this study investigated river sediments in Shanghai, the largest urban area in China. Seven sites were sampled to ensure maximum coverage of the city's central districts, and a tidal flat was also included to compare with river samples. Density separation, microscopic inspection and μ-FT-IR analysis were conducted to analyze the characteristics of microplastics and the type of polymers. The average abundance of microplastics in six river sediment samples was 802 items per kilogram of dry weight. The abundance in rivers was one to two orders of magnitude higher than in the tidal flat. White microplastic spheres were most commonly distributed in river sediments. Seven types of microplastics were identified, of which polypropylene was the most prevailing polymers presented. The study then conducted risk assessment of microplastics in sediments based on the observed results, and proposed a framework of environmental risk assessment. After reviewing waste disposal related legislation and regulations in China, this study conclude that in situ data and legitimate estimations should be incorporated as part of the practice when developing environmental policies aiming to tackle microplastic pollution.

Microplastics in Freshwater River Sediments in Shanghai, China: A Case Study of Risk Assessment in Mega Cities

Microplastics in soil: A review on methods, occurrence, sources, and potential risk.

The chemistry of chemical recycling of solid plastic waste via pyrolysis and gasification: State-of-the-art, challenges, and future directions

Microplastics in the environment: A critical review of current understanding and identification of future research needs

Textbooks are still accepted as one of the most influential materials used during instruction today. On the other hand technological devices and processes have been used more during instruction as in every field in our lives. Therefore, this study aims to assess technology integration into textbooks for students’ motivation. In this context, science lesson textbooks from 3rd to 8th grades were examined in terms of included technological concepts or technology use in the activities and handled digital competences. The study is carried out with the document analysis method in a qualitative research and it is found that technology, television, telephone and computer are the most used concepts in textbooks. And also it is found that “information and data literacy” and “communication and collaboration” competences identified in the European Digital Competency Framework are used most in the textbook activities. “Digital content creation” and “problem solving” competences are included less in the textbook activities. Depending on the data obtained from the study, it is suggested that the use of only QR codes in textbooks is not sufficient and the use of different technological methods and techniques should be used more.

The Assessment of Technology Integration into Science Lesson Textbooks

Extended Abstract Microplastic pollution has become a global concern, particularly in the last decade due to their rapid increase in the environment. Rivers are the major transport pathways of microplastics to reach the marine environment. Understanding how microplastics are distributed horizontally and vertically in rivers is a requirement to assessing the risks associated with microplastic abundance. This study aims to investigate the effect of flow characteristics on the transport of microplastics and identify transport of these particles mechanistically between a tributary and main stream of the Ergene River, Turkey using mass-balance and hydrodynamic equations. For this purpose, Corlu tributary of the Ergene River was chosen as the study area. River samples were collected from the six stations of the Ergene River including Corlu tributary and upstream and downstream of the outfall of this tributary in September 2020. Fifteen litres of water sample were collected from the water surface of each sampling station using stainless-steel buckets and transferred to glass bottles. Additionally, the parameters including flow rate (m s -1 ) and stream depth (m) of the river were measured using Acoustic Doppler Current Profiler instrument. After removing organic matter, the collected water samples were filtered onto a plankton mesh with 45 µm pore size. Microplastic particles were visually identified under stereo-microscope (Olympus SZX 16, 30x) and transferred to a clean cellulose filter paper, previously checked for airborne contamination. Microplastic particles were photographed and counted by the help of ImageJ software.

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Zeynep Akdogan

Papers

Microplastics in the environment: A critical review of current understanding and identification of future research needs

The Assessment of Technology Integration into Science Lesson Textbooks

Assessing Transport of Microplastics in the Ergene River