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.

3 Mar 2026

The Use of Nitrocellulose Production Waste for Energy Generation

Abstract: The US Army Engineer Research and Development Center investigated the use of nitrocellulose (NC) fines, an ammunition waste, for energy generation. NC is a natural high polymer obtained from treating cotton or wool with nitric and sulfuric acid. It is widely used in the industry, with military applications being the largest use currently. Since military applications range from bullet propellants to missiles for tube munitions, large quantities must be produced to meet the demand. However, large NC production batches result in large quantities of NC fines waste, generated in the form of insoluble fibers in suspension in wastewater after manufacturing. Hence, a method to reuse this generated waste and convert it into energy was tested. This study evaluated the potential of creating energy from NC waste through hydrothermal liquefaction and gasification of NC, yielding methane (CH4) as the final product. Results demonstrated that the CH4 concentrations increased as the temperature, reaction time, and catalyst addition were increased, yielding a maximum concentration of 2,000 ppm (6,400 peak area of the chromatograph). The homogenous catalyst performed better than the heterogenous catalyst, since it increased the CH4 yield up to 6 times the concentration obtained with no catalyst added.

3 Mar 2026

Overview of PFAS in Aquatic Environments

Abstract: PFAS are highly stable fluorinated compounds with unique properties and are used in a broad array of industrial processes and commercial products. PFAS are extremely recalcitrant and are widespread in the environment, with measurable concentrations in soils, sediments, groundwater, surface water, and rainwater, even at sites far removed from known sources or releases. Select PFAS (especially longer-chain perfluorinated carboxylic and sulfonic acids) are known to bioaccumulate in aquatic food webs, presenting potential risk to higher trophic species, including hu-mans. Evidence suggests sediment serves as a repository and potential ongoing source for many of these long-chain PFAS. The global presence and persistence of PFAS pose a fundamental challenge to addressing potential effects on environmental quality and health. The public and policymakers are increasingly concerned about the potential presence and effects of PFAS in water and sediments. This concern includes knowledge gaps for dredged material management, posing challenges to execution of the US Army Corps of Engineers Civil Works navigation program. This document provides a comprehensive review of PFAS in the aquatic environment based on published studies and includes overviews of chemical classifications, regulatory considerations, historical uses and sources, environmental distribution, fate and transport pathways, and uptake and effects in aquatic organisms.

20 Feb 2026

Demonstration Validation of Industrial Supercritical Water Oxidation (iSCWO) PFAS Destruction Technology: Aqueous Film-Forming Foam Treatment by General Atomics (GA) iSCWO System

Abstract: The Department of Defense (DoD) is confronted with a pressing environmental challenge concerning legacy aqueous film-forming foam (AFFF) concentrate, historically used in firefighting activities. Legacy AFFF contains PFAS, which are identified as persistent environmental contaminants associated with adverse health effects. Considering increasing environmental regulations and concerns regarding human health impacts, the DoD needs to properly destroy legacy AFFF. The US Army Engineer Research and Development Center (ERDC) led a project focused on the demonstration and validation of technologies for the destruction of PFAS in AFFF. Results are presented for the treatment of 100 gal. of AFFF using the General Atomics industrial Supercritical Water Oxidation system. The demonstration showed destruction removal efficiencies (DREs) for total PFAS analyzed via total oxidizable precursor (TOP) assay (S24 PFAS), ranging from 98.5% to 99.9991%. No volatile fluorinated compounds were detected in the stack emissions as analyzed via Other Test Method 50; however, up to 6,000 ppt S51 PFAS as analyzed via TOP assay was detected in demister effluent. The energy consumed per cubic meter of AFFF and order of magnitude S24 PFAS destroyed ranged from 2 to 24 MWh, while the energy consumed per gram of S24 PFAS destroyed ranged from 0.046 to 48 MWh.

18 Feb 2026

Infection Risk Assessment for Socially Structured Population Using Stochastic Microexposure Model

Abstract: Predicting infection outbreak dynamics within local microenvironments is a challenging task. Some methods assume smaller population pools and often lack the statistical power of inferences. Others are designed for larger population pools and cannot be downscaled to accommodate the details of microenvironments. Practicable infection risk assessment models should account for population size, geometry and occupancy of public places, behavioral and professional patterns of daily routines, and societal structure. This study is based on the stochastic microexposure model, which has been generalized to describe clustered populations. The methodology is demonstrated for a community of several thousand students on campus. The results indicate the social structure has the first order effect on the spread of the infection. Depending on the number, size, and degree of inner- and outer-cluster connections, the outbreak exhibits distinct durations, power, and multiple peaks of infection. Moreover, the contribution of different microenvironments to infection risk evolves during the course of the outbreak. Social structure plays a major role in infection spread and should be accounted for in risk prediction tools. The stochastic microexposure model accounts for the social structure of a population at multiple scales and can predict the dynamic contributions of different microenvironments to infection spread risks.