We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Denser microplastics migrate deeper? Effect of particle density on microplastics transport in artificial and natural porous media
Summary
Researchers conducted saturated column experiments with polyethylene microspheres of different densities in glass bead and gravel porous media to investigate how particle density affects microplastic transport behavior, finding that density significantly influences MP fate and providing transport model fits with R2 above 82.3%.
Predicting the fate of microplastics (MPs) in porous media has been challenging and previous research mainly focused on the transport of MP considering plastic size and shape effects, media size effects, and solution chemistry effects. However, few studies examined the plastic density impact on the transport behavior of MPs in porous media. This is significantly important to gain insight into how the MP density influences its fate in the environment. Therefore, column experiments under saturated conditions were conducted to explore the MP transport in columns packed with glass beads and gravel and using polyethylene microspheres with different densities within the same size range together with a conservative tracer. Experimental results were fitted well (R2 > 82.3-98.7 %, and low RMSE value) with a two-site transport model with a depth-dependent blocking function in HYDRUS-1D. The results showed that particle density influences the transport of MPs, and the deposition rate varied with particle density in the following order: 1.12 g/cm3 > 0.995 g/cm3 > 1 g/cm3. This suggests that compared to neutrally buoyant and buoyant MP, denser MPs tend to deposit in the selected material under the tested flow rate. The coupled experimental and simulated results indicate that denser MPs may be retained but neutrally buoyant MPs can be potentially migrated with infiltrated water into subsurface systems, thus posing groundwater contamination risk. Hence, further studies are needed with viable densities and diverse conditions to advance the understanding the impact of plastic density on its transport fate.Keywords: Microplastics, density, transport, sediments, glass beads
Sign in to start a discussion.
More Papers Like This
Effect of particle density on microplastics transport in artificial and natural porous media
Researchers studied how the density of microplastic particles affects their movement through soil and sediment in laboratory column experiments. They found that lighter, less dense microplastics traveled farther and were retained less in the soil compared to denser particles, and that natural sediments captured more microplastics than uniform glass beads. The findings help explain how different types of microplastics spread through groundwater and soil environments at different rates.
Impact of particle density on the mobility of microplastics in sediments
This study investigates how the density of microplastic particles affects their mobility through soil and potential to reach groundwater, using column experiments with polyethylene particles of different densities. Particle density was found to influence transport behavior, with implications for understanding how microplastics migrate through terrestrial environments.
Subsurface transport of microplastic particles in gravel columns: Impacts of different rain events and particle characteristics
Researchers conducted column experiments using pre-stained microplastic particles of two density types in gravel sediment to investigate how different rainfall intensities and land-use scenarios influence the vertical transport and retention of microplastics in subsurface environments. The study found that both particle density and rainfall event characteristics significantly affected microplastic mobility through subsurface sediments, informing models of microplastic fate in soil-water systems.
Subsurface transport of microplastic particles in gravel columns: Impacts of different rain events and particle characteristics
Researchers conducted column experiments using 110 cm wet-packed fine gravel columns to examine subsurface transport of two microplastic types — polystyrene (denser than water) and polyethylene (less dense than water) at 50 µm median size — under different simulated rainfall scenarios including continuous rain, wet-dry cycles, and single events followed by drying. They found that particle density, rainfall pattern, and subsurface heterogeneity all influenced microplastic vertical transport and retention depth in gravel sediments.
Flume experiments on transport and deposition behavior of microplastics in sediment bed environments
Researchers ran 42 flume experiments with three model sediments and spherical microplastics of varying size and density, finding that deposition depth is governed by sediment porosity and the grain-to-particle diameter ratio, while transport is primarily controlled by particle density and initial placement, providing data to improve MP mass balance models.