Microplastics, Volume 3, Issue 3 (September 2024) – 3 articles

Carbopol^® is a typical jelly agent belonging to the family of cross-linked polyacrylic acid copolymers. It is largely used in antibacterial gels due to its self-wetting properties. In its pristine physical form, Carbopol^® falls under the definition of microplastics, though significant changes could occur once added to hydroalcoholic solvents of the liquid formulations. To date, no life-cycle data regarding the physical state are available for this substance or for other similar polymers of the same chemical class. The aim of the present study was the investigation of the fate of Carbopol^®-derived microplastics used in the formulation of typical hand sanitizer gels available in the Italian market, such as Amuchina^® X-Germ, along the product life cycle. An experimental model was designed to detect the presence of Carbopol^® microparticles from product manufacturing to the final use. FTIR and µ-FTIR were used to detect and characterize solid particles after the optimization of the sample preparation of different experimental matrices. While Carbopol^® as such can be classified as a microplastic, in the commercial product, Carbopol^® particles were not detected. Ten volunteers used the product according to the instructions reported on the label, and finally they rinsed their hands. Carbopol^®-based particles were not detected in the water rinse, indicating that, after usage, the original form of the Carbopol microparticles was not retrieved. The study proposes, for the first time, a simple and comprehensive experimental approach to identify and characterize microplastics in finished products and along the life cycle by simulating their real-life usage. This approach could be also useful to evaluate the release of chemical components into the environment through the use of dermal products. Full article

Microplastics are contaminants in marine ecosystems, posing great threats to biota and human health. In this work, we provide an overview of the progress made in understanding microplastic prevalence in tropical coastal environments, focusing on the Johor and the Singapore Straits as a case study. We examine the sources, distribution, transport, and ecological impact of microplastic pollution in this region through a systematic review. All papers relating to marine microplastics in Singapore’s sand and benthic sediments, seawater, and marine biota were used for analysis, from 2004 to 2023. In addition, we discuss the influence of envi-ronmental factors such as coastal morphology and anthropogenic activities on patterns of microplastic accumulation. We emphasize that microplastic pollution is more prevalent along the eutrophic Johor Strait compared to the Singapore Strait due to hydrological conditions. Rainfall is also a key factor that influences mi-croplastic abundance during the monsoon seasons. Furthermore, the bacterial and plankton assemblages of organisms on microplastic surfaces are diverse, with eutrophic waters enhancing the diversity of organisms on microplastic surfaces. Novel harmful cyanobacteria and bloom species of phytoplankton were also found on microplastic surfaces. By synthesizing existing research findings and highlighting regional characteristics, this paper contributes to ongoing efforts to mitigate microplastic pollution in tropical regions. Full article

Microplastic distribution surveys centered on Korea’s Gwangyang Bay and southern coastal waters. Gwangyang Bay seawater averaged 3.17 ± 1.23 particles/L, and sediments averaged 462.4 ± 143.9 particles/kg. The southern coastal seawater averaged 0.10 ± 0.09 particles/L, and the sediments averaged 50.6 ± 29.7 particles/kg. Microplastics flowing from land, through physical modeling of ocean currents in Gwangyang Bay and southern coastal waters, pass through the Yeosu Strait and flow into the southern coastal waters. At the same time, it is judged that the southern coastal waters showed somewhat lower abundance than the Gwangyang Bay waters because they move toward the Korean Strait due to the Jeju warm current water and Tsushima current water, strongly generated in summer. In addition, the seawater microplastic abundance showed a higher abundance than that on the site adjacent to the land in the southern coastal waters, which is the study area. On the other hand, the results for sediment microplastic abundance were opposite to the surface seawater microplastic results. Therefore, it is judged that entering one source of pollution does not affect the distribution of microplastics in Gwangyang Bay and southern coastal waters, but rather this occurs in different forms. Full article