Microplastic Abundance in Human-Influenced Soils in Recreational, Residential, and Industrial Areas (original) (raw)
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Studia Ecologiae et Bioethicae, 2022
In less than a century, plastics have gained enormous popularity and it is now difficult for us to imagine our lives without them. They are very widely used in industry, agriculture, medicine and many others, mainly due to their stability and low production costs-which contribute to a steady increase in demand worldwide. They biodegrade very slowly, and the limited and inappropriate recovery of this raw material from waste has led to a visible accumulation of residual polymers in the environment. As a result of physical, chemical and biological processes, e.g., ultraviolet (UV) radiation, weathering or mechanical abrasion, plastics degrade to fine particles-those less than 5 mm in size are called microplastics. They can be found in the natural environment in various morphological forms, e.g., as fibres, granules, scraps, spheres, particles or fragments, e.g., film, of primary or secondary origin. The presence of microplastics has been found all over the world, in all environments. Only recently has there been a broader focus on microplastics, which includes terrestrial systems where soils are an important part of the environment potentially exposed to contamination. Their main source in soils may be within agriculture (where composts, organic fertilizers, sewage sludge and mulching, as well as irrigation are used) plus transport, landfills and the deposition of atmospheric pollutants.
Microplastics in Terrestrial Soils: Occurrence, Analysis, and Remediation
Energy, Environment, and Sustainability, 2021
The production of synthetic polymers has increased in manifolds since the advancement of petroleum engineering. These cosmopolitan artificial materials are now persistent in almost every ecosystem on planet earth. This could be attributed to the higher tendency of polymer disintegration and lower polymer degradation in the ambient environments. The processes of polymer disintegration lead to the formation of microscopic plastic particles, referred to as ‘microplastics’. Significant research in emerging environmental contaminants focuses on microplastics, their occurrence in terrestrial and aquatic ecosystems, and adverse effects on biota, humans and other environmental compartments. Therefore, taking account of the background, this chapter summarizes the different strategies for the chemical extraction of microplastics from soil samples and further qualitative and quantitative analysis via distinct spectrophotometric techniques. All over the world, rivers, lakes, and associated floodplains are some of the most polluted ecosystems. The Indian rivers, including Meghna, Brahmaputra and Ganges are polluted with 72,845 tonnes of plastic loads per annum which eventually is transported into the oceans. The existing literature also presents a picture that microplastic pollution studies are usually focused on aquatic ecosystems such as oceans, lakes and rivers. However, microplastic pollution in floodplain soils is a major neglected research question. Therefore, this chapter aims to focus on the occurrence of microplastics in terrestrial soils such as floodplains, their origin and sources, and how to extract and quantify microplastic presence in the geological samples. Furthermore, microplastics are non-uniform in terms of their physicochemical characteristics and degradation. Numerous forms of microplastics pollute aquatic and terrestrial ecosystems. Therefore, an emphasis is also laid down on the microplastic control and remediation techniques in these natural ecosystems for scientific inquiry.
Agriculture
While microplastics (MPs) have been identified extensively in aquatic ecosystems, their presence remains largely unexplored in soil ecosystems. Considering the potential effect of MPs on soil biodiversity and function, the present study investigated and analyzed the abundance and characteristics of MPs in soil profile. Taking soil samples from Tainan city farms, as one of the hotspots of agricultural practices in Taiwan, concentrations, types, compositions, pathways, and sources of MPs in farmland soils were quantified. Results showed that MPs were found in all soil samples in different depths ranging from 12–117 items/m2 and MP abundance in farms adjacent to the suburban roads was about three times more than in enclosed farms separated from roads. Fragment and fibers were the main forms and low-density polyethylene was the dominant polymer of detected MPs. Historical land use, extensive application of plastic mulch, and utilization of fruit protection foams were identified as the m...
2021
Although the distribution of microplastic (MPs) has been studied in different environmental compartments during the last decade, there is still a knowledge gap in their distribution and abundances in soil. This study aimed to investigate the abundance, distribution, and type of MPs in the soil of Aghili plain as a hot and dry area in southwest of Iran. In this study, composite soil samples (n=102) were collected from the residential and agricultural areas in Aghili plain, Iran. A combination of visual observations, Scanning Electron Microscopy (SEM) – Energy-dispersive X-ray spectroscopy (EDS), and Raman micro -spectroscopy was conducted to quantify and characterize MPs in soil samples. The intakes of MPs in adults and children were estimated through two exposure EPA scenarios. The total MPs loading in the studies soil was 11.93 ± 0.9 items in Kg-1 of surface soil in Aghili plain. The MPs had various morphology (fiber, pellet, fragment, and spherule shapes), colors (white-transparen...
Microplastics in soils: an environmental geotechnics perspective
Journal of Environmental Geotechnics, 2021
Microplastics (MPs) are emerging persistent contaminants in the terrestrial subsurface, and evidence has emerged for significant effects of MPs on soils’ biological and ecosystem functions. Main MPs sources include land spreading of sewage sludge and biowaste composts, plastic mulching film used in horticultural fields, wastewater irrigation, and leachate from the landfills, amongst others. This updated state-of-the-art review paper describes recent experimental and numerical research and developments in understanding the accumulation, fate and effects of MPs in soil environment (focusing on their storage, degradation, transportation, leaching to groundwater, etc.), followed by mitigation and bioremediation measures, including soil bacterial- and fungus-eating MPs, best management practices for reducing MP pollution of soil, etc. Other areas covered are the combined effects of MPs and various other environmental contaminants (heavy metals, organic pollutants and antibiotics) in soil ecosystems, and standardization of methods for detection, quantification and characterisation of MPs in soils, which is critical for MPs research. The paper concludes by identifying knowledge gaps and presents recommendations on prioritized research needs.
Microplastic contamination in soil environment -a review
SOIL SCIENCE ANNUAL, 2020
Plastic is an indispensable material essential for modern human life. With highly increasing de- mand for plastic use, however, environmental contamination by plastic litters has become an emerging issue. Globally, large quantity of used plastics is landfilled or emitted directly to the aquatic and terrestrial environments, albeit a part of the plastics is recycled or incinerated as energy source. In particular, microplastic debris that are smaller than 5 mm are considered to be emerging contaminants of global concern. In the past decade, however, most of the researches on impacts of microplastic contamination have been focused on the marine ecosystem, whereas very limited ones on the terrestrial ecosystem. Soil can be considered as a major sink and a car- rier of microplastic contaminants to the aquatic environment. Most sources of microplastics in the soil environment are entered via a variety of routes and subsequent fragmented and spread to the surrounding environments, vertically and horizontally. In addition, there are negative im- pacts on soil biota, which in turn would cause concerns of human health by affecting the food web. Here, we provide an overview of characteristics, research trend, analytical methods, migra- tion and degradation processes, effects on soil biogeochemistry, and interaction with soil organ- isms of microplastics suggesting the importance of ongoing research impacts of microplastics on the terrestrial ecosystem.
Microplastics as pollutants in agricultural soils
Environmental Pollution, 2020
Microplastics (MPs) as emerging persistent pollutants have been a growing global concern. Although MPs are extensively studied in aquatic systems, their presence and fate in agricultural systems are not fully understood. In the agricultural soils, major causes of MPs pollution include application of biosolids and compost, wastewater irrigation, mulching film, polymer-based fertilizers and pesticides, and atmospheric deposition. The fate and dispersion of MPs in the soil environment are mainly associated with the soil characteristics, cultivation practices, and diversity of soil biota. Although there is emerging pollution of MPs in the soil environment, no standardized detection and quantification techniques are available. This study comprehensively reviews the sources, fate, and dispersion of MPs in the soil environment, discusses the interactions and effects of MPs on soil biota, and highlights the recent advancements in detection and quantification methods of MPs. The prospects for future research include biomagnification potency, cytotoxic effects on human/animals, nonlinear behavior in the soil environment , standardized analytical methods, best management practices, and global policies in the agricultural industry for the sake of sustainable development.
Urban dust and civil runoff could represent a critical diffuse source of MPs in urban areas. • Several studies indicated that Tyre and Road Wear Particulates could be an important source of MPs pollution. • The main drivers influencing MPs distribution in the soil are the application of plastic mulch films and sewage sludge. • Particles <10 μm have been found in fruits and vegetables commonly consumed by humans with worrying values. • Several authors observed the variation of nutritive values of some edible vegetables due to MP interactions.
Analysis and Effects of Microplastics in the Agricultural Soils
Proceedings of the 7th World Congress on New Technologies, 2021
Microplastics (MPs) are pertinacious contaminants which are threatening the delicate balance of the ecosystem. Over the years, various studies have reported the presence of MPs in the marine environment through case studies and reviews, but its presence in the agricultural soils is not fully understood. To date, there exists no standardized methodology for sampling, extraction and characterization of MPs in the agricultural soils. This review aims at encapsulating the different techniques used for sampling and extraction of MPs, and includes the methods employed for identification and quantification of MPs in the soil environment. Flotation method, pressurized fluid extraction and elutriation are some of the different techniques used for MPs extraction that usually influence the characterization step. Visual identification through microscope and scanning electron microscope and chemical identification via Fourier-transform infrared (FITR) and Raman spectrometry, are the main techniques that are used for the identification of MPs. The fate and dispersion of MPs in the agricultural soil are discussed, as well as their interaction with the soil biota. The main findings of this review show that further research is needed on the sampling methods as well as analytical techniques so as to contribute to standardizing MPs characterization in the soil environment, potential toxicity effects along the food chain, and global policies for sustainable development.
Science of The Total Environment, 2020
Plastic pollution is one of the major challenges in the Anthropocene. A plastic waste sub-product, microplastics (<5 mm), has been regarded as contaminants of concern for its detrimental effects and widespread in the environment. Most studies assessing microplastics focused on marine environments, while terrestrial and soil systems have been overlooked. In this review, we analyzed the current knowledge regarding microplastic pollution in natural soil or agricultural ecosystems. We focused on reviewing the procedural steps for microplastic extraction and identification in detail. The heterogeneity of the methods applied, lack of standardized procedures and incompatible parameters reported, make the results incomparable among most studies. Several microplastic concentration units are needed to make studies comparable. Correctly determining and reporting microplastic morphotypes are key to understanding the sources of contamination. Minimal considerations and recommendations were stated for extraction, digestion, filtration, and polymer identification procedures. Baseline contamination prevention measures were identified as mandatory along the entire sampling, handling and identification procedures. Lastly, knowledge gaps were identified and discussed for further research.