Search

Agricultural production uses different types of fertilisation treatments, typically employing the combined application of organic fertiliser (OF) or organic-inorganic fertiliser (OIF) to improve soil quality. When coupled with cadmium (Cd), microplastics (MPs) affect plant growth and Cd accumulation in soils treated with different fertilisers. This study systematically examined the effects of polyurethane (PU) MPs coupled with Cd on the growth characteristics, root metabolite characteristics, rhizosphere bacterial community structure, and Cd bioavailability of maize under different long-term fertilisation treatments and soil types (red/cinnamon soil). The combined effects of PU MPs and Cd on maize growth differed across fertilisation treatments. Under OF, maize plants accumulated more Cd than under OIF. The accumulation of Cd in maize plants in red soil was twice that in cinnamon soil. Under OF, PU MPs promoted Cd activation by decreasing the soil pH, while root metabolites promoted Cd adsorption sites by synthesising specific amino acids, degrading aromatic compounds, and synthesising pantothenic acid and coenzyme A. Under OF, PU MPs can lower the soil pH to promote the activation of cadmium, while root metabolites promote root growth and increase cadmium adsorption sites by synthesizing specific amino acids, degrading aromatic compounds, and synthesizing pantothenic acid and coenzyme A, hereby promoting root Cd absorption. Under OIF, PU MPs act by influencing the biosynthesis of amino acids in root metabolites, enriching energy metabolism pathways, promoting the transport and translocation of mineral nutrients, thereby amplifying the "toxic effects" of Cd. This study provides new insights into the risk assessment of PU MPs and Cd coupling under different fertilisation treatments, and suggests that the prevention and control of combined PU MPs and Cd pollution in red soil under OF treatment should receive more attention in the future., Competing Interests: Declaration of Competing Interest We declare that there is no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Microplastics (MPs) as new environmental pollutants are receiving increasing attention worldwide. Urban rainwater runoff plays an important role in facilitating the migration of land-based MPs to surface water. Previous research has focused predominantly on aquatic ecosystems, whereas research on this migration pathway and the characteristics of MPs in rainwater pipelines draining from different land-use types is still lacking. This study investigated the abundance and characteristics of MPs in rainfall and pipeline rainwater runoff from main roads, office complexes, an agricultural experiment station, and residential areas during different rainfall periods in Haidian District, Beijing, China. Microplastic abundance in pipeline rainwater runoff ranged from 1.6 to 29.6 items L -1 , of which 0.7 to 6.0 items L -1 were derived from rainfalls, accounting for 24.0 % to 77.4 % of the total. Microplastic abundances in rainfall and pipeline rainwater runoff decreased significantly as rainfall events progressed. The proportions of MPs < 1 mm in rainfall (38.0 %) and rainwater runoff (44.5 %) were the largest. Average MPs abundance was the highest in rainwater runoff from the main road area and lowest in the office area (p < 0.05). The abundance of polyester fibers in rainwater runoff from the residential area was significantly higher than that in other areas, while the main road area had the highest abundance of films (p < 0.05). Overall, 72 % of MPs in rainfall were fibers, and most were composed of polyester, while the MPs in rainwater runoff were mainly fragments (41.2 %) and fibers (35.3 %) composed mainly of polypropylene, polyethylene, and polyester. This study shows that urban pipeline rainwater runoff is one of the main pathways for land-based MPs transport to surface waters, and provides a scientific reference for preventing and controlling MPs entering water bodies through rainwater pipelines., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Microplastics (MPs) pollution in the environment has become a global hotspot, but there is insufficient research on MPs in soils of large cities. This study investigated the pollution status of MPs in soils in different functional areas (commercial, tourist, industrial, and residential areas) of the Xi'an metropolitan area. The average abundances of MPs were 2218 items/kg in Xi'an city, 1329 items/kg in Xianyang city and 1400 items/kg in Yangling city. All MPs presented different shapes and were dominated by fragment and fiber. The 0-0.5 mm MPs accounted for the largest proportion. Polyethylene terephthalate (PET) was the predominant polymer type for MPs. The results showed that the soil in the Xi'an metropolitan area was polluted by MPs, with the pollution of MPs in Xi'an city being more severe than other two cities. This could be related to the advanced urbanization and industrialization process. Moreover, industrial and tourist areas had frequent industrial and human activities, so their MPs pollution was the worst. In addition, residential areas and some commercial areas far away from pollution sources had lower pollution levels and a more uniform distribution of MPs. This study may provide data and valuable reference for the investigation of soil MPs pollution in the Xi'an metropolitan area., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Microplastic (MP) pollution in terrestrial ecosystems has aroused great concern. However, little is known regarding the distribution of MPs in Sand Land soils and their associated destinies. We investigated the MPs pollution in different areas, different vegetation cover and restoration years in Mu Us Sand Land soils. The results clearly showed that the soils of Mu Us Sand Land contain a relatively higher MPs abundance. The significant differences of MPs abundance were demonstrated among soil from sand, grassland and woodland, which the total MP abundance of sand soil was higher than that of grassland and woodland. The distribution of MP size in the woodland area primarily from 0 to 0.50 mm, which is significantly higher than that other areas. In addition, the highest concentration of MP collected was found at Salix tree (ST), followed by Poplar tree (PT) and Chinese pine (CP), while the lowest concentration was at Pinus sylvestris (PSs) and Jujube tree (JT). It is worth noting that the abundance of MPs decreases with restoration years increased, whether it is PT or PSs. We speculate that the tree disturbance in the sampling area might affect the distribution of microplastics and then be conducive to plastic fragmentation., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Combined pollution from microplastics (MPs) and cadmium (Cd) can influence soil environment and soil biota, altering plant growth and development, and Cd mobilization. We investigated the effects of polystyrene (PS) and polypropylene (PP) MPs alongside Cd on soil Cd bioavailability, rhizosphere soil metabolomics, bacterial community structure, and maize (Zea mays L.) growth in two soil types (red soil and cinnamon soil). Although the addition of PS/PP-Cd promoted Cd accumulation in maize plants overall, there were large-particle-size- and small-particle-size-dependent effects in the red soil and cinnamon soil, respectively. The difference is mainly due to the capacity of the large particle size MPs to significantly reduce soil pH, improve soil electrical conductivity (EC), promote active Cd, and intensify Cd mobilization in red soil. In contrast, small-size MPs in cinnamon soil promoted the synthesis and secretion of rhizosphere amino acids and soil metabolites, thus promoting Cd absorption by maize roots. Soil microorganisms also improved Cd bioavailability via C-related functional bacteria. Overall, our study provides novel insights on the potential effects of combined MPs and Cd pollution on soil ecology and agricultural production, enhancing our understanding of rhizosphere metabolites in different soils. [Display omitted] • Soil type controls PS/PP-Cd pollution effects on maize growth and development. • PS/PP-Cd pollution significantly promotes Cd accumulation in maize plants • Differences in Cd accumulation between red and cinnamon soil depend on MPs size. • Active Cd, amino acid synthesis, and key functional bacteria promote Cd availability. [ABSTRACT FROM AUTHOR]

The extensive application of organic fertilizers for agricultural use has been considered as a main source of microplastics (MPs) in soils. However, how long-term organic fertilizer applications affect MPs accumulation in soils is poorly understood. Therefore, MPs were characterized in chicken manure (CM), sludge (SC), and domestic waste (DW) composts applied as organic fertilizers, and effects of long-term compost applications on soil MPs accumulation and vertical distribution were explored in a 13-year wheat–maize cropping rotation field experiment. Microplastics concentrations in CM, SC, and DW composts were 14,720 ± 2,468, 8600 ± 1,428, and 11,640 ± 3565 items kg−1, respectively, and after 13 years of addition, MPs concentrations in soils were 2733 ± 160, 2289 ± 270, and 2462 ± 247 items kg−1, respectively. Microplastics concentrations were significantly higher in soils with composts than in those without. Accumulated MPs in soils derived from long-term compost applications ranged from 3.63 × 109 to 4.99 × 109 items ha−1, which were amounts 3 to 4 times higher than those input by composts, indicating MPs derived from composts can be gradually decomposed into smaller pieces after incorporation into soils under long-term application. The percentage of MPs >1 mm in composts (55.4%) was higher than that in soils with composts (40.7%), and abundance and size decreased with increased soil depth. Shapes and polymer composition were similar between composts and soils with composts. Most MPs were different colored fibers and fragments of polypropylene and polyethylene. To conclude, long-term application of organic composts increases MPs pollution risk in agricultural soils, which needs to be evaluated further. [Display omitted] • Long-term composts application dramatically increased soil microplastics (MPs). • Accumulated soil MPs from composts was 3–4 times higher than input by composts. • Microplastics in soils from composts accounted for 52%–60% of the total. • Microplastics abundance and size decreased with increasing soil depth. • Composts and soils with composts had similar MPs shapes and polymers. [ABSTRACT FROM AUTHOR]