Microplastics in Swiss Floodplain Soils.

Occurrence characteristics and potential risk of microplastics under different land conditions

Accumulation of microplastics (MPs) in soil is a worldwide concern, but a standardized analysis method for soil MPs has not been established yet. In this study, we compared deionized water, zinc chloride and sodium iodide solution with specific gravities of 1.0, 1.4 and 1.5, respectively, for the separation of MPs in paddy soil that had a history of coated fertilizer application. Organic matter in the paddy soils was digested with Fenton’s reagent (30% peroxide and 0.05 M iron sulfate) before density separation. Separation efficiency of MPs in soil was significantly high for sodium iodide, followed by zinc chloride, then water. The abundance of MPs in the soil ranged 100 - 5800 pieces/kg. The particle sizes of MPs in the soil were found to be extremely small, ranging from 1 - 111 μm. Since paddy fields are waterlogged during plantation and are drained about two weeks before harvest, large MPs might be flushed out by water. It can be concluded that MPs in paddy soil may have large range of plastic materials with different gravity and small particle size.

Analysis of microplastics in soils on the high-altitude area of the Tibetan Plateau: Multiple environmental factors.

Plastic pollution is an emerging issue faced worldwide owing to rapid urbanization and extensive use of plastic products. The objective of this study was to determine and highlight the spatial distribution of microplastics (MPs) in the top soils of different land use types of an urbanized city, i.e., Lahore, Pakistan, influenced by different human activities. Soil samples (n = 40) were collected from eight different land use groups including agricultural areas, drains, dumping sites, industrial areas, lawns, parks, roadsides, and wastelands to represent the influence of corresponding human actions. After cleaning the samples through wet peroxide digestion and density separation, MPs were identified under a stereomicroscope. The range of MPs in top soils within Lahore district varied from 1750 to 12,200 MPs/kg with an average of 4483 ± 2315 MPs/kg. The highest concentration of MPs was present in the parks while the lowest numbers of MPs were enumerated in soil from dumping sites. About 99% of the identified MPs particles were fibers, sheets, and fragments in shape while foams and beads accounted for the rest. Moreover, among the size ranges, the large size MPs (300-5000 μm) were found in the majority (41.16%) followed by the fine size MPs (50-150 μm; 30.67%) and medium size MPs (150-300 μm; 28.17%). The current level of MPs pollution attracts the attention of researchers for a more comprehensiveinvestigation in the future. It also incites the policy-makers to implement the regulations toprevent plastic pollution and its environmental implications.

Microplastics (MPs) have been extensively studied in aquatic systems; however, their presence in general agricultural systems and in particular, soil still needs comprehensive understanding. This study conducted a field survey at 25 sites to investigate the abundance of MPs in agricultural soil. The MPs in these soil samples were separated using sieves and filters by the density separation method with NaCl solution (d = 1.2 g/cm3). The density of MPs in agricultural soils ranged from 1,700 items/kg to 38,800 items/kg, with an average of 11,716 ±10,726 items/kg. The black-colored MPs were found to be dominant, followed by white, purple, red, and blue. The fibers represented most of the MPs' shapes observed in this research (77.9±17.4%). MPs in agricultural soil samples were tiny particles with sizes of <1,000 µm and 1,000-2,000 µm. A significant difference was observed in the concentration of MPs in locations near and far from residential areas and manufacturing facilities. The average concentration of MPs in the soils adjacent to the residential and manufacturing facilities and near the agricultural solid waste collection sites was 21,471±12,729 items/kg and 20,188±4,403 items/kg, much higher than in distant these locations at 4,418±1,573 items/kg. These results suggest that domestic, industrial, and agricultural activities could contribute to MP pollution in agricultural soil. The ecological dangers MPs pose in terrestrial and aquatic environments have drawn much attention from the scientific community. This work represented the first effort to comprehend the ecological risk of MPs on selected samples of Vietnamese agricultural soil. According to the Pollution Load Index (PLI) values, most agricultural soil samples in this study were contaminated with MPs at hazard level IV. The potential ecological risk index (PERI) values of agricultural soil samples from nearby residential, industrial, or agricultural solid waste areas indicated a higher ecological risk.

Contribution of mulch film to microplastics in agricultural soil and surface water in China

Microplastics (MPs) in soil cause severe damage to the ecological environment and organisms, and research on their health risks has received extensive attention, but there is no comprehensive review of this research. From the perspective of bibliometrics, this paper systematically and comprehensively describes the progress, trends, and hotspots of health risks of MPs in soil based on the Web of Science Core Collection, Pubmed, and Scopus databases. Since 2016, people’s research on the health risks of MPs in soil has increased yearly; MPs in soil mainly come from Plastic mulch, Plastic waste, Sludge and sewage, and Organic fertilizer. China has the most publications on the health risks of MPs on soil, and more than half of the top 10 institutions with active publications in this field are from China. This paper systematically expounds on the health risks of MPs to organisms (plants, humans, and microorganisms) and control measures. Cooperation between different countries/institutions and fields/disciplines on the health risk analysis of MPs in soil and research on more efficient, green, and environmentally friendly methods and technologies for reducing soil MPs content will become the frontier trends of future development which provide valuable reference and help for future researchers.

The occurrence and distribution characteristics of microplastics in the agricultural soils of Shaanxi Province, in north-western China

Fate and abundance of antibiotic resistance genes on microplastics in facility vegetable soil

Microplastics in soils during the COVID-19 pandemic: Sources, migration and transformations, and remediation technologies

Systematic assessment of data quality and quality assurance/quality control (QA/QC) of current research on microplastics in biosolids and agricultural soils

Microplastics (MPs) are plastic fragments with particle sizes smaller than 5 mm that have potentially harmful effects on ecosystems and human health. The soil environment is not only the source but also the sink of MPs. Thus, it is necessary to fully understand the pollution and distribution of MPs in soils. In this study, Qinghai Province, northeast of the Qinghai–Tibet Plateau, was selected as the research area, and 22 soil samples were collected and analyzed to study the levels and distribution characteristics of MPs in grassland soils. MPs were obtained from the soils by using density separation, and a laser confocal micro Raman spectrometer was used for MP identification. The results showed that MPs were detected in all of the soil samples. The total abundances of MPs ranged from 1125 to 1329 items/kg, with a mean abundance of 1202 items/kg. Various types, shapes, sizes, and colors of MPs were observed. Polyethylene terephthalate (PET) was the dominant polymer in all the grassland soil samples. The size range of 10–50 μm accounted for 50% of all identified MPs. Pellets were the dominant MP shape, and colored MPs accounted for 64% of all MPs. The results revealed the presence of large quantities of MPs in the grassland soils of remote areas as well. This study can act as a reference for further studies of MPs in terrestrial systems. At the end of the paper, the prospects and suggestions for pollution control by soil MPs are given.

Contamination by microplastics (MPs) has the potential to rank among the world’s most significant environmental issues. Despite the fact that MP contamination is a global problem, little is known about the time variation of MPs in agricultural soil and its faunal communities which represent a key role to risk assessment. This study represents a first field investigation regarding the MP concentrations in agricultural ecosystem in Egypt. Our study investigates the seasonal fluctuations of MPs in soil and its common fauna in a citrus orchard (Citrus sinensis) in Egypt’s Sohag Governorate. Moreover, this work aimed to identify how feeding strategies and body size of the selected fauna affect the no. of MPs ingested. The greatest mean concentration of MPs in soil was observed in summer (664 ± 90.20 items/kg) dry weight. However the lowest was recorded in autumn (354 ± 70.92 items/kg). Aporrectodea caliginosa (earthworms) was more contaminated with MPs (6.84 ± 2.5 item/individual annually) than Anisolabis maritima (earwigs) (2.06 ± 0.86 item/individual annually). When comparing between taxa without considering the size of the organisms, earwigs showed higher MPs concentrations (ranged from 117.93 ± 5.23 to 244.38 ± 4.57 items/gm wet weight) than the earthworms (ranged from 25.62 ± 2.43 to 51.66 ± 4.05 items/gm wet weight). Our results found that blue and red colors were the predominant colors in the soil and the selected fauna. Also, polyester fibers (PES) were the most popular type of microplastics, followed by fractions of polyethylene (PE) and polypropylene (PP). Interestingly, the reduction in the MP particles in the present taxa was observed compared to those in the soil. Pollution load index (PLI) value varied across seasons, with the lowest recorded in autumn due to reduced MPs abundance. The Hazard (H) index indicates a moderate risk (level III) due to high polyester abundance and a low hazard score (4) across all seasons. Our results represent a starting point for further studies on the impact of MPs on soil organisms in various agricultural soils.

Critical evaluation of hyperspectral imaging technology for detection and quantification of microplastics in soil

The widespread occurrence of microplastics (MPs) in agricultural soils raises global concern, yet a systematic understanding of their national‐scale distribution and drivers remains elusive. Here, we present the first comprehensive, nationwide analysis of MPs in Chinese farmland soils, integrating abundance, morphology, and polymer data from 169 sites across 31 provinces with regional agricultural practices and soil properties. The results showed that the abundance of MPs in Chinese farmland soils ranged from 240 to 12,720 items kg −1 . Among the identified MPs, films were the predominant morphological category, accounting for 58.4%, while small‐sized particles dominated across dimensional distributions, accounting for 65.5%. Polyethylene (PE) was consistently the most prevalent polymer in all soil samples analyzed, accounting for 36.5%. The analysis results further clarified the key driving factors of MP distribution. The accumulation of MPs in soil environments resulting from local agricultural and human activities, or atmospheric deposition, may affect the transport and accumulation of small‐sized MPs. Soil properties also affected the distribution characteristics of MPs. The abundance of MPs and pH were significantly and negatively correlated ( p < 0.01). Soil electrical conductivity (EC) had a significant positive correlation with the abundance of fiber MPs ( p < 0.05), and coarse sand content was positively correlated with pellet MP counts ( p < 0.05). This study establishes that MP pollution in Chinese farmland is a spatially structured mosaic, governed by both human input and soil‐specific retention. Our findings provide an empirical basis for targeted source control (e.g., plastic mulching film management) and advance risk assessment by incorporating soil‐mediated fate processes.