Evaluating emerging organic contaminant removal in an engineered hyporheic zone using high resolution mass spectrometry

Is the Hyporheic Zone Relevant beyond the Scientific Community?

“…Novel methods such as highly dynamic sampling of pore water [223], time-integrated passive sampling techniques [177], and isotopic techniques are under development and will allow better insights into hyporheic processes. Peter et al [33] injected visible dye into shallow HZ sediments in a known downwelling location and pinpointed the area where the labeled flowpath re-emerged to the stream. Piezometers and seepage meters were installed at these locations and used to collect paired influent-effluent samples and determine the water treatment occurring along the flowpath.…”

“…The efficiency of river restoration structures can likely be improved by attending to design variables that can alter HZ functioning. Example variables include controlling hydraulic gradients (e.g., the height of a step [218]), manipulating hydraulic conductivities (e.g., with sediment coarsening [248]), changing flowpath geometries (e.g., with baffle walls [54,249] or hyporheic caps and increased HZ depth [33]), or shielding a structure from groundwater upwelling or downwelling (e.g., with a liner). Future research should focus on tailoring river restoration practices to deliver specific regulating ecosystem services, while also recognizing that in-channel structures alone are not able to overcome catchment-scale degradation of these services [250].…”

“…Further research has investigated biogeochemical processing in the HZ. While earlier studies focused on nutrients [28,29] and mining-derived pollutants, such as metals [30], recent papers have begun to investigate emerging pollutants, such as microplastics [31], pesticides [32], organic stormwater contaminants [33], and pharmaceuticals [34,35]. Even though there has been so much HZ research published in recent decades, it is unclear whether the hyporheic zone is of any relevance beyond the scientific community.…”

Hyporheic Process Restoration: Design and Performance of an Engineered Streambed

“…The large variability of vertical flux over time, and over short spatial distances, could lead one to suspect methodological imprecision. However, Peter et al [30] confirmed by direct observation that hyporheic pathways, and presumably fluxes, do change radically over short time periods. These authors conducted tests using visible die tracers to map specific hyporheic pathways through plunge-pool No.…”

Co-Design of Engineered Hyporheic Zones to Improve In-Stream Stormwater Treatment and Facilitate Regulatory Approval

“…Efforts to improve contaminant removal in-stream could better incorporate the hyporheic zone (HZ), which has been referred to as a river's liver due to its unique role as a natural biofilter [26]. Located in streambed sediments at the interface of surface water and groundwater, the HZ is known to attenuate a variety of stormwater and wastewater contaminants found in urban streams [27][28][29][30][31]. However, urban HZs are often scoured and clogged by hydromodification that limits their contributions to water quality [32], and there are no widely adopted stormwater BMPs that explicitly harness the HZ.…”