We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Microplastic accumulation in riverbed sediment via hyporheic exchange from headwaters to mainstems
AI summary Read the abstract
Researchers developed a model showing that hyporheic exchange between river surface water and sediment causes long-term microplastic retention, with headwater residence times averaging 5 hours per kilometer but increasing to 7 years per kilometer during low-flow conditions.
In rivers, small and lightweight microplastics are transported downstream, but they are also found frequently in riverbed sediment, demonstrating long-term retention. To better understand microplastic dynamics in global rivers from headwaters to mainstems, we developed a model that includes hyporheic exchange processes, i.e., transport between surface water and riverbed sediment, where microplastic retention is facilitated. Our simulations indicate that the longest microplastic residence times occur in headwaters, the most abundant stream classification. In headwaters, residence times averaged 5 hours/km but increased to 7 years/km during low-flow conditions. Long-term accumulation for all stream classifications averaged ~5% of microplastic inputs per river kilometer. Our estimates isolated the impact of hyporheic exchange processes, which are known to influence dynamics of naturally occurring particles in streams, but rarely applied to microplastics. The identified mechanisms and time scales for small and lightweight microplastic accumulation in riverbed sediment reveal that these often-unaccounted components are likely a pollution legacy that is crucial to include in global assessments.
More Papers Like This
Significance of Hyporheic Exchange for Predicting Microplastic Fate in Rivers
AI summary Read the abstract
Researchers modeled the role of hyporheic exchange — water flow between rivers and streambed sediments — in driving microplastic delivery and retention in riverbeds, finding that this process significantly increases the rate at which small and positively buoyant microplastics are transported into streambed sediments. The study highlights hyporheic exchange as an underappreciated mechanism controlling microplastic fate in freshwater environments.
Integrated numerical modeling of microplastic transport in fluvial systems
AI summary Read the abstract
This study developed an integrated numerical model for microplastic transport in rivers that accounts for both surface water flow and exchange with the hyporheic zone — the subsurface region where river water mixes with groundwater. Including hyporheic exchange improved predictions of microplastic storage and remobilization compared to surface-only models. The work helps explain why microplastics are often found at higher concentrations in river sediments than in the water column.
Integrated modeling of microplastics in the hyporheic zone
AI summary Read the abstract
A combined field and modeling study investigated how microplastics interact with the hyporheic zone — the region of sediment beneath and alongside rivers where surface water and groundwater mix. The study found that microplastics can be transported into and retained in hyporheic sediments through infiltration processes, acting as a significant and poorly understood sink. Better models of hyporheic microplastic dynamics are needed to accurately account for plastic retention in river systems.
The transport behaviour of microplastics in longitudinal mixing and hyporheic exchange under varied flow conditions
AI summary Read the abstract
Researchers studied how microplastics move through river systems, examining both downstream transport and how particles interact with riverbeds through hyporheic exchange. Understanding these transport behaviors helps predict where microplastics accumulate in river sediments.
Modelling the Fate of Microplastics in river bed sediments.
AI summary Read the abstract
Researchers modeled microplastic transport, deposition, and burial in river bed sediments under varying hydrological conditions. River bed sediments were found to act as long-term reservoirs for microplastics, with periodic high-flow events temporarily resuspending and redistributing particles.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.