13 Apr 2026

Review of Emerging and Nonconventional Analytical Techniques for Per- and Polyfluoroalkyl Substances (PFAS): Application for Risk Assessment

Abstract: Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that pose significant risks to ecosystems and human health. Increasing regulatory demands for PFAS management have increased the need for rapid and deployable analytical technologies for both abiotic and biotic matrices. Traditional detection methods, such as standardized chromatography, often require weeks to months for analysis due to a limited number of appropriately accredited laboratories, delaying critical decision-making. This literature review is intended to identify promising emerging PFAS analytical techniques or technologies to facilitate more rapid (near real-time) analysis and explore their relevancy in supporting human and ecological risk assessments. Recently developed optical and electrochemical sensing approaches are enabling the detection of PFASs within minutes to hours, with detection limits typically aligning within reported ambient concentrations in water, soil, and sediment. These emerging technologies could (1) support planning and prioritization of sampling efforts during the problem formulation phase of risk assessment, (2) complement traditional chromatography methods to lower time and resource demands to improve sampling frequency over space and time, and (3) aid in risk-informed characterization of PFAS exposures based on identified chemical classes or groups. This review highlights those approaches and technologies that could potentially enhance the comprehensiveness and efficiency of PFAS risk assessment across diverse environmental settings in the future.

9 Apr 2026

Identifying Overwintering Habitat of Silver and Bighead Carp in the Lower Mississippi River: Implications for Harvesting and Population Reduction

Purpose: A total of 41 sites along a 58 mi reach of the Lower Mississippi River (LMR) were surveyed during winter 2022 for invasive carp aggregation. Sites consisting of scallops closest to the dike-vegetated bank interface with deeper, slow-moving water and consistent access back to the main channel were preferred. Carp avoided strong currents, and there was no trend in depth selection other than avoiding shallow (less than 20 ft) water. In January 2023, recreation-grade sonar (e.g., side-scan and down-imaging) surveys were conducted in the same reach of the LMR to demonstrate the technology and evaluate carp population size at sites with high abundances based on previous surveys. Fish density was estimated to be 32 fish/10,000 yd3 (95% confidence interval [CI; 31–34]) using down-imaging software, which is the first estimate of assumed bigheaded carp density in the LMR. Additional fish collections are needed to confirm species composition and size abundance provided by sonar technology. Resurveying sites with high carp abundance over a range of river stages would be necessary to fully characterize habitat conditions, evaluate influence of river stage on occupancy duration, and continue to evaluate species composition and mass removal techniques as a management option in the Lower Mississippi River.

9 Apr 2026

Photocatalytic Degradation of Microcystins from a Field-Collected Cyanobacterial Assemblage by 3D Printed TiO2 Structures Using Artificial Versus Solar Irradiation

Abstract: Microcystins from freshwater cyanobacteria cause adverse effects to humans and ecological receptors through multiple exposure routes requiring adaptable and diverse treatment technologies. Photocatalysis of MCs using TiO2 is a promising technology; however, TiO2 photocatalysts as unbound nanoparticles in suspension are impractical to deploy. 3D Printing provides a means to immobilize TiO2, producing deployable photo-catalyst structures with extensive geometric freedom. The objective of this proof-of-concept experiment was to incrementally increase the environmental complexity while comparing photocatalysis rates of MCs by 3DP TiO2 structures using polylactic acid as the binder. Degradation half-lives of MCs were shorter in TiO2 embedded in 3DP PLA relative to PLA-only controls with differences in half-lives ranging from 3.6 to 10h. The one exception was the outdoor solar and an algal assemblage, where significant differences could not be discerned due to the already rapid photolysis rates. Ultimately, photocatalysis rates were comparable to those previously published for TiO2 3DP structures in a laboratory environment and TiO2 fixed- films demonstrating feasibility of 3DP to immobilize TiO2 photocatalysts under a range of conditions. This is the first time that MC concentrations from a field-collected HAB were photocatalytically degraded in both solar simulated light and sunlight using a custom-made advanced photocatalytic nano- composite with enhanced performance through high surface area design enabled by 3D printing. These data inform future development of scalable, retrievable, and operationally flexible structures with immobilized TiO2.

9 Apr 2026

Round Robin Experiment to Detect, Size, and Characterize Flaws in the Welds of Existing Hydraulic Steel Structures Using Phased Array Ultrasonic Testing

Abstract: Limited information exists on the ability of nondestructive testing techniques to detect, size, and characterize flaws in existing hydraulic steel structures (HSS). Round robin experiments were conducted using phased array ultrasonics to inspect welded steel specimens representing joints in existing HSS. Technicians detected 83% of the flaws scanned, but detection rates varied widely by flaw and technician. Uncertainty in flaw size estimates, represented by 90% confidence bounds on the ratio of estimated to actual length or height, ranged from 0.52 to 2.10 for length and 0.32 to 3.59 for height. Planar, volumetric and laminar flaws were accurately characterized 80% of the time.

9 Apr 2026

Effects of Exopolysaccharides from Rhizobium tropici on Transformation and Aggregate Sizes of Iron Oxides

Abstract: Iron oxide transformations in soil significantly impact nutrient availability and plant health. This study investigated the interaction between exopolysaccharides (EPS), produced by Rhizobium tropici, and iron oxide (Fe3O4), focusing on their impact on the transformation, particle size, and zeta potential of iron oxides. The characterization of the EPS-iron oxide composites was carried out using X-ray Powder Diffraction (XRD), Fourier Trans-form Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Analysis (EDX). The EPS adsorption kinetics revealed chemisorption and diffusion as controlling processes for EPS adsorption on Fe3O4, while isotherm data with releasing proton indicated possible ion exchange and heterogeneous layered adsorption. Desorption studies suggested the high stability of EPS-iron complexes. Notably, EPS significantly increased the aggregate size of EPS-iron complexes at low EPS/iron oxide molar ratios but shrank the aggregate size at higher ratios. Additionally, EPS complexation resulted in a shift in the zeta potential towards more negative surface functionality. Functional groups within EPS, specifically –COOH, –OH and –NH played a crucial role in the interaction of EPS with iron oxides. The study concluded that EPS coating prevented the transformation of Fe3O4 into other iron oxide forms like β-FeOOH, α-Fe2O3, and γ-Fe2O3, elucidating the significant role of EPS in soil mineral processes.

30 Mar 2026

Water Injection Dredging—Screening for Suitability: Research and Development of Screening Criteria to Determine the Suitability of Water Injection Dredging

Abstract: Innovative technologies for sediment management could reduce dredging costs and enhance benefits from sediment resources. Water injection dredging (WID) has the potential to improve sediment management in channels and reservoirs in the United States, but conditions for feasibility and favorable applications must first be established. WID works by fluidizing a sediment bed, causing it to flow down gradient or to spread as a density current. Fluidization testing on a range of sediments shows that the liquidity index might be an effective indicator of a sediment’s susceptibility to fluidization via WID. To assess the anticipated effectiveness of WID, a series of experiments were conducted to evaluate the fluid mud properties of sediment from Tuttle Creek Lake, Kansas, where WID has been proposed for reservoir management. Laboratory investigations were conducted to evaluate settling characteristics, viscosity, and angles of repose of the fluid mud over a range of concentrations. Large-scale flume experiments were also conducted to track the velocity and slope of the density current. Results were used to evaluate the flow characteristics of a density current generated by WID.

26 Mar 2026

Lifecycle Cost and Benefit Analysis for Parcel-Scale Implementation of Green Stormwater Infrastructure

Abstract: Green stormwater infrastructure (GSI) is commonly implemented to reduce excess stormwater runoff while also producing secondary environmental, health, and aesthetic benefits. However, GSI is sometimes perceived to be cost prohibitive for limited-budget site development projects. This study used lifecycle cost analysis (LCCA) and benefit-cost analysis (BCA) to investigate the cost-effectiveness of GSI combined with conventional stormwater infrastructure for a proposed parcel development site in Oxford, Mississippi, USA. Hydrologic modeling was conducted for a conventional underground detention facility as well as three GSIs (permeable pavement, rain garden, and grassy ditch), all of which met regulatory runoff attenuation targets for the site. The LCCA considered capital and operation and maintenance (O&M) costs. Benefits were estimated under six categories – water, energy, climate, air quality, health, and community – based on existing tools for economic analysis of low impact development (LID). Economic benefits and costs over different scenarios of project lifecycles were compared using the present value (PV) approach in the benefit cost analysis (BCA). The lifecycle costs of two of the three GSIs (rain garden and grassy ditch) were lower than for the conventional alternative alone. However, in all three GSI cases, the long-term benefits of GSI features outweighed the costs. The methodology presented can be adapted to other locations to inform analyses of lifecycle costs and benefits and identify GSI and hybrid infrastructure options that are financially and environmentally feasible.

24 Mar 2026

Intraspecific Variation in Rapid Cold Hardening and Acclimation of the Adventive Parrot’s Feather Weevil, Phytobius (=Parenthis) Vestitus, in the Southern USA

Abstract: Plasticity in thermal tolerance, expressed through acclimation or rapid cold hardening, for example, provides organisms with a mechanism to deal with unexpected and often rapid changes in the thermal environment. Spatial variation in response to high or low temperatures may occur due to evolutionary adaptation, particularly if a fitness increase coincides with the ability to respond quickly to environmental change. Thermal tolerances of beneficial insects used for biological control dictate where and under what thermal conditions the insects will provide value to management programs. We investigated two aspects of thermal phenotypic plasticity in response to thermal conditions using four populations of the adventive parrot’s feather weevil, Phytobius vestitus, from the southern USA. At low temperatures, we determined the presence and variation in rapid cold hardening in one of the four populations using two temperature ramping rates. In contrast, at high temperatures, all P. vestitus populations displayed a significant heat acclimation response, documented as elevated loss of motor control and motor function temperatures after acclimation. Thus, observed patterns of plasticity differed between high and low temperatures and among source populations. These results demonstrate the presence of geographic variation in phenotypic plasticity in response to thermal environments and emphasizes the need to consider plasticity when selecting climate-adapted populations of biological control agents.

24 Mar 2026

Developing a Habitat Suitability Index with Field Data and Hydraulic Models

Abstract: Linking habitat availability with hydraulic models integrates river engineering in the ecological field. Field observation for species presence and physical habitat availability mapping is inherently limited due to time and access constraints for field data collection. This study leverages hydraulic modeling to supplement larval fish population monitoring data, effectively expanding mapped physical habitat and allowing for monitoring bias analysis. The inundation extents and character of streamflow from hydraulic modeling were used to refine habitat suitability indices relative to total habitat availability from discrete fish monitoring events. Given the flexibility in hydraulic modeling to simulate a range of flows, the habitat suitability index is then translated to an effective habitat curve according to areal inundation and hydrologic frequency. With this framework, forecasting the impacts of long-term trends, such as geomorphic or hydrologic change, can be reasonably and quantitatively assessed. This manuscript uses a case study of Rio Grande silvery minnow monitoring at restoration sites where the floodplain has been lowered via earthwork. Comparisons are made for habitat suitability indices developed from field observation data alone and field observation supplemented by hydraulic modeling. Known biases of field sampling data were confirmed based on simulated hydraulic conditions across entire restoration sites. In the case of Rio Grande silvery minnow, a heavily studied species, such field monitoring biases are an effective use of resources. However, this framework may be helpful for assessing alternative management approaches and monitoring strategies of species that are less studied.

23 Mar 2026

Assessment of Aluminum-Based Drinking Water Treatment Residuals from Multiple Utilities in the United States as Green Sorbents for PFAS

Abstract: Per- and polyfluoroalkyl substances are persistent environmental contaminants causing human health concerns. In this study, five aluminum-based drinking water treatment residuals were evaluated as green adsorbents for the removal of perfluorooctanoic acid and perfluorooctanesulfonic acid from water. Al-WTRs are nonhazardous solid wastes generated during the coagulation process of water treatment using aluminum salts or polymers. Although high PFAS adsorption capacity of Al-WTRs generated in one facility in the US has been reported, no study exists assessing PFAS adsorption capabilities of WTRs generated in multiple facilities using various types of aluminum coagulants. Batch adsorption experiments of PFOA and PFOS on Al-WTRs showed removal efficiencies exceeding 70 % for PFOA and 94 % for PFOS across all Al-WTRs. Maximum adsorption capacities for PFOS were significantly higher than those for PFOA, indicating the stronger affinity of the Al-WTRs for PFOS. Low desorption rates for both PFOA and PFOS suggested irreversible adsorption. Correlation analysis revealed that oxalate-extractable Al, Fe, and organic matter primarily contributed to PFOA adsorption, while pore size, oxalate-extractable Al, Fe, and total calcium primarily contributed to PFOS adsorption. These easily measurable parameters could be used as predictors when utilizing Al-WTRs as sustainable sorbents for PFAS removal. This study not only establishes the comparative and predictive performance of Al-WTRs from multiple utilities for PFAS sorption but also demonstrates their recycling potential within a circular-economy framework.