Microplastics are continuously released into the terrestrial environment from sources where they are used and produced. These microplastics accumulate in soils, sediments, and freshwater bodies, and some are conveyed via wind and water to the oceans. The concentration gradient between terrestrial inland and coastal regions, the factors that influence the concentration, and the fundamental transport processes that could dynamically affect the distribution of microplastics are unclear. We analyzed microplastic concentration reported in 196 studies from 49 countries or territories from all continents and found that microplastic concentrations in soils or sediments and surface water could vary by up to eight orders of magnitude. Mean microplastic concentrations in inland locations such as glacier (191 n L−1) and urban stormwater (55 n L−1) were up to two orders of magnitude greater than the concentrations in rivers (0.63 n L−1) that convey microplastics from inland locations to water bodies in terrestrial boundary such as estuaries (0.15 n L−1). However, only 20% of studies reported microplastics below 20 μm, indicating the concentration in these systems can change with the improvement of microplastic detection technology. Analysis of data from laboratory studies reveals that biodegradation can also reduce the concentration and size of deposited microplastics in the terrestrial environment. Fiber percentage was higher in the sediments in the coastal areas than the sediments in inland water bodies, indicating fibers are preferentially transported to the terrestrial boundary. Finally, we provide theoretical frameworks to predict microplastics transport and identify potential hotspots where microplastics may accumulate.
The current study examines the contamination of microplastics in three greenhouse types: abandoned, normal, and simple. The findings revealed that the abundance of microplastics was found to be the highest in the abandoned greenhouse, followed by the normal greenhouse and simple greenhouse. The mean abundance of microplastic organic fertilizer and irrigation water was also high.[…]
The study examines the distribution of residual film after eight years of film mulching in mid-April 2018. Results from the study revealed that eight years of mulching significantly increased the quantity of agricultural mulch film residues in the soil. The size of residual film fragments was found to vary from 0.25 cm2 to 109 cm2,[…]
A study in Yuanmou County, Yunnan Province, investigated microplastic pollution in different land uses, including facility farmland, traditional farmland, orchard, grassland, and woodland. Results showed a significant difference in microplastic abundance and characteristics between different land use types. Facility farmlands, traditional farmlands, and orchard lands had higher microplastic abundance than grasslands and woodlands. The main[…]
The study analysed 225 soil samples from maize planting zones in northern China, revealing that long-term plastic film mulching increases microplastic pollution in agricultural soils. The abundance of microplastics was significantly higher in mulched soils (754 ± 477 items kg-1) than in non-mulched soils (376 ± 149 items kg-1). The length of time with film[…]
The study examined the relative abundances and morphological distributions of microplastics (MPs) in water, sediments, and farmland soils in the Caohai Lake region. The estuary in the study area was considered a potential sink for MP transportation. Transparent and black MPs accounted for a large proportion of MPs in the five environments, with possible sources[…]