The ubiquity of microplastics in aquatic and terrestrial environments and related ecological impacts have gained global attention. Microplastics have been detected in table salt, drinking water, and air, posing inevitable human exposure risk. However, rigorous analytical methods for detection and characterization of microplastics remain scarce. Knowledge about the potential adverse effects on human health via dietary and respiratory exposures is also limited. To address these issues, we reviewed 46 publications concerning abundances, potential sources, and analytical methods of microplastics in table salt, drinking water, and air. We also summarized probable translocation and accumulation pathways of microplastics within human body. Human body burdens of microplastics through table salt, drinking water, and inhalation were estimated to be (0-7.3)×104, (0-4.7)×103, and (0-3.0)×107 items per person per year, respectively. The intake of microplastics via inhalation, especially via indoor air, was much higher than those via other exposure routes. Moreover, microplastics in the air impose threats to both respiratory and digestive systems through breathing and ingestion. Given the lifetime inevitable exposure to microplastics, we urgently call for a better understanding of the potential hazards of microplastics to human health.

https://findresearcher.sdu.dk:8443/ws/files/168676998/A_Review_of_Microplastics_in_Table_salt_Drinking_Water_and_Air.pdf

A Review of Microplastics in Table Salt, Drinking Water, and Air: Direct Human Exposure

Ecotoxicity and genotoxicity of polystyrene microplastics on higher plant Vicia faba.

Microplastics in wild fish from North East Atlantic Ocean and its potential for causing neurotoxic effects, lipid oxidative damage, and human health risks associated with ingestion exposure

The qualitative and quantitative composition of biofilms on microplastic surfaces is widely unknown. A previous study (Zettler et al., 2013; EST) reports the presence of potentially pathogenic bacteria (Vibrio spp.) on floating microplastic particles. Hence microplastics could function as vectors for the dispersal of microorganisms to new habitats. Several Vibrio species are serious human pathogens. Contact with contaminated water and consumption of raw seafood are the main infection factors for Vibrio associated diseases. On research cruises to the North- and Baltic Sea, microplastic particles were collected and subjected to APW (alkaline peptone water) enrichment. Growth on selective CHROMagar™ Vibrio and further identification of isolates by MALDI-TOF (matrix assisted laser desorption/ionization time-of-flight) clearly indicate the presence of potentially pathogenic Vibrio spp. on microplastics. Our results highlight the urgent need for detailed microbiological analyses of floating microplastic particles in the future.

Dangerous hitchhikers? evidence for potentially pathogenic vibrio spp. on microplastic particles

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

Previous studies have identified microplastics (MPs) in commercial table salts but could not exactly address the origin of the MPs because of several limitations. The present study is based on the hypothesis that commercial sea salts can act as an indicator of MP pollution in the surrounding environment unless the MPs are filtered out during the manufacturing process. A total of 39 different salt brands produced at geospatially different sites, including 28 sea salt brands from 16 countries/regions on six continents, were investigated. A wide range of MP content (in number of MPs per kg of salt; n/kg) was found: 0–1674 n/kg (excluding one outlier of 13 629 n/kg) in sea salts, 0–148 n/kg in rock salt, and 28–462 n/kg in lake salt. Relatively high MP content was identified in sea salts produced in Asian countries/regions. The abundance of MPs in unrefined sea salts (n = 25) exhibited significant linear correlations with plastic emissions from worldwide rivers (r2= 0.33; p = 0.003) and with the MP pollution ...

Global Pattern of Microplastics (MPs) in Commercial Food-Grade Salts: Sea Salt as an Indicator of Seawater MP Pollution.

Abundance and characteristics of microplastics in soils with different agricultural practices: Importance of sources with internal origin and environmental fate.

Variation and Uncertainty of Microplastics in Commercial Table Salts: Critical Review and Validation

Importance of seasonal sea ice in the western Arctic ocean to the Arctic and global microplastic budgets

This study was conducted to evaluate and to increase the usage of the whole onion (Allium cepa L.), which is composed of a small bulb and many leaves that are discarded as by-products before the bulbs grow. Whole onions are harvested early in immature condition, which allows the other onion bulbs to grow well. We compared its functional activities with those of quercetin, which is one of its major components. The antioxidant activities of ethanol extract from the whole onion (WOEE) were measured by DPPH and ABTS radical scavenging activities, and superoxide dismutase (SOD) and catalase (CAT) activities. The anti-inflammatory effects of WOEE were investigated in RAW 264.7 macrophages treated with LPS by analyzing cytokine levels and expressions using ELISA kits and RT-PCR assays, respectively. WOEE showed high antioxidant effects on DPPH and ABTS radical scavenging activities, and SOD and CAT activities. WOEE significantly reduced the production of nitric oxide, IL-1β, IL-6, and TNF-α, and/or their mRNA expressions in a dose-dependent manner. The results indicated that whole onions had antioxidant and anti-inflammatory effects, which were comparable with quercetin and may be used as a novel potential therapeutic candidate.

/pdf/antioxidant-and-anti-inflammatory-effects-of-ethanol-extract-3it5g1s2.pdf

Ji-Su Kim

Papers

Global Pattern of Microplastics (MPs) in Commercial Food-Grade Salts: Sea Salt as an Indicator of Seawater MP Pollution.

Abundance and characteristics of microplastics in soils with different agricultural practices: Importance of sources with internal origin and environmental fate.

Variation and Uncertainty of Microplastics in Commercial Table Salts: Critical Review and Validation

Importance of seasonal sea ice in the western Arctic ocean to the Arctic and global microplastic budgets

Antioxidant and Anti-Inflammatory Effects of Ethanol Extract from Whole Onion (Allium cepa L.) with Leaves