We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Distribution of microplastics in soil and freshwater environments: Global analysis and framework for transport modeling
Summary
Researchers analyzed microplastic concentrations reported across 196 studies from 49 countries and found that levels in soils, sediments, and surface water can vary by up to eight orders of magnitude. The study suggests that inland sources like urban stormwater carry concentrations up to 100 times higher than rivers transporting microplastics to coastal areas, and that only 20% of studies captured particles below 20 micrometers, meaning actual contamination may be significantly underestimated.
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) and urban stormwater (55 n L) were up to two orders of magnitude greater than the concentrations in rivers (0.63 n L) that convey microplastics from inland locations to water bodies in terrestrial boundary such as estuaries (0.15 n L). 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.
Sign in to start a discussion.
More Papers Like This
Global concentrations of microplastic in soils, a review
This global review synthesized data from studies on microplastic concentrations in soils worldwide, finding contamination across diverse terrestrial environments with higher levels near urban areas and agricultural land. Terrestrial soils are estimated to contain far more microplastic than the world's oceans, making them a critical but understudied reservoir of plastic pollution.
Quantitative assessment on the distribution patterns of microplastics in global inland waters
Researchers compiled data from over 5,000 observations across 301 published studies to map microplastic levels in freshwater bodies worldwide, finding concentrations ranging from near zero to 4.3 million particles per cubic meter. Human development, farming activity, and water runoff were the strongest predictors of contamination, with China and parts of Asia showing particularly high levels.
Microplastics in urban stormwater sediments and runoff: An essential component in the microplastic cycle
This review systematically analyzed microplastic contamination in urban stormwater runoff and sediments, finding concentrations that varied enormously across global studies. Researchers found that stormwater is a major but underappreciated pathway for delivering microplastics to rivers, lakes, and oceans. The study highlights that better stormwater management practices are needed to reduce this significant source of aquatic microplastic pollution.
Microplastics in ecosystems: Critical review of occurrence, distribution, toxicity, fate, transport, and advances in experimental and computational studies in surface and subsurface water
This review provides a broad overview of microplastic contamination across freshwater, marine, and land environments, finding concentrations ranging from negligible to hundreds of thousands of particles per kilogram of sediment. The most common types are polypropylene, polystyrene, polyethylene, and PET, spread by wastewater discharge, stormwater runoff, and poor waste management. The wide variability in contamination levels makes it difficult to assess overall risk to ecosystems and human health.
Factors Controlling Microplastic Concentrations and Polymer Profiles in Wastewater, Storm Water, and Surface Water
A critical review of 143 studies found that microplastic concentrations in wastewater span eight orders of magnitude, with the highest levels in the smallest particle size fractions, while polyethylene and polypropylene are the most commonly detected polymers across freshwater systems. The wide variation is largely an artifact of inconsistent sampling, extraction, and analytical methods, making direct comparisons between studies unreliable and complicating decisions about water treatment and regulation.