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Purpose: To determine and compare the frequency of contamination on different sites of healing abutments (HAs) a=er steriliza3on with Phloxine B dye on unused and used HAs a=er steriliza3on. Materials and Methods: A total of 60 HAs were divided into two test groups: (1) used and sterilized and (2) a control group (unused). The test group was evaluated for contamina3on a=er steriliza3on; the control group did not undergo any procedure. Data were analyzed using SPSS version 22 (IBM). Descrip3ve sta3s3cs were used to determine the frequency of contamina3on in the different groups and at the different HA sites. Chi-square test was used to evaluate the association of frequency of contamination with the HA site and design. The level of significance was kept at P ≤ .01. Results: The test group showed more contamination compared to the control group. The most contaminated sites were the screw thread and the screwdriver engagement location. Conclusions: HA reuse is cost-effective, but cleaning and sterilization was not effective for these components; thus, HAs need to be reused with caution because they were heavily contaminated when compared to new HAs. Among the different sites, the screw thread and screwdriver engagement sites were more prone to contamination. HA type did not influence the frequency of contamination. [ABSTRACT FROM AUTHOR]

African American (AA) women confront distinct disparities in breast cancer rates, and the impact of their living environment is unclear. This study aimed to examine the association between breast cancer incidence and environmental factors among a high-risk female population. The study recruited 355 AA women ages 20–88 in Memphis from 2016–2018. Their addresses were geocoded and linked to environmental and socioeconomic data. The final dataset contained 50 cases and 157 controls. Associations between breast cancer incidence and social and environmental factors were examined using logistic regression. Spatial analysis in ArcGIS showed that cases clustered in Southwest Memphis. Proximity to traffic and Superfund sites had odds ratios of 1.636 (95% CI: 25 1.046, 2.560) and 12.262 (95% CI: 1.814, 82.864), respectively. Mediating analyses further revealed that environmental inequities contributed significantly to breast cancer inequalities. In conclusion, the built environment plays a role in breast cancer onset among AA females. [ABSTRACT FROM AUTHOR]

Crude oil contamination has been widely recognized as a major environmental issue due to its various adverse effects. The use of inhabitant microorganisms (native to the contaminated sites) to detoxify/remove pollutants owing to their diverse metabolic capabilities is an evolving method for the removal/degradation of petroleum industry contaminants. The present study deals with the exploitation of native resident bacteria from crude oil contaminated site (oil exploration field) for bioremediation procedures. Fifteen (out of forty-four) bioremediation-relevant aerobic bacterial strains, belonging to the genera of Bacillus, Stenotrophomonas, Pseudomonas, Paenibacillus, Rhizobium, Burkholderia, and Franconibacter, isolated from crude oil containing sludge, have been selected for the present bioremediation study. Crude oil bioremediation performance of the selected bacterial consortium was assessed using microcosm-based studies. Stimulation of the microbial consortium with nitrogen or phosphorous led to the degradation of 60–70% of total petroleum hydrocarbon (TPH) in 0.25% and 0.5% crude oil experimental sets. CO2 evolution, indicative of crude oil mineralization, was evident with the highest evolution being 28.6 mg mL−1. Ecotoxicity of treated crude oil-containing media was assessed using plant seed germination assay, in which most of the 0.25% and 0.5% treated crude oil sets gave positive results thereby suggesting a reduction in crude oil toxicity. [ABSTRACT FROM AUTHOR]

Since the 1980s, low-permeability slurry trench cutoff walls have been widely constructed as barriers to retard the migration of contaminants. The thickness of the cutoff walls is a key determinant of the wall service life. Through a series of theoretical derivations, simplified methods for determining the flux limit and concentration limit were proposed to determine the thickness of cutoff walls for contaminated sites with constant pollutant flux. The relative errors of both the flux-based and concentration-based methods increase as the breakthrough criterion of the ratio between the specified limit concentration of the contaminant to the source concentration (C*) and the ratio of the limited value of contaminant flux to the constant source flux (F*) increases, with a given Peclet number PL. The maximum relative error reaches 4% and 6% when C* and F* are both 0.1, which covers most practical situations in cutoff wall design. Good agreements of wall thickness were obtained between the proposed simplified methods and analytical solutions via a clear example. The proposed method can efficiently simplify the design process of cutoff walls with high accuracy, providing a basis for containing contaminated sites. [ABSTRACT FROM AUTHOR]

This study investigated how adding stable manure affected the transport of atrazine within agricultural soils from Kahramanmaraş, Turkey. Based on the batch and miscible-displacement experiments, it was found that atrazine sorption was nonlinear, following a Freundlich isotherm, and was rate-limited and reversible for both the non-amended and amended soil. The addition of manure resulted in higher retardation of atrazine, with R values of 10.1 to 19.1, compared to values of 3.2 to 4.3 for the non-amended soil. The KF values for stable-manure amended soil calculated from batch experiment was three times higher than non-amended soil. The transportation of atrazine shows non-ideal behavior, characterized by significant elution tailing at low concentrations due to the organic carbon content of the soil. This effect was more prominent in soil with a 10% stable-manure amendment. By incorporating non-linear sorption, a two-site transport modeling approach provides a reasonably accurate representation of the atrazine breakthrough curves. The distinct sorption-desorption characteristics of atrazine have significant implications for risk assessment of atrazine-contaminated soil and should be considered in the regulation, management, and remediation of such contaminated sites. [ABSTRACT FROM AUTHOR]

The widespread use of petroleum-based fuels poses a significant environmental problem due to the risks associated with accidental spills. Among the treatments available, phytoremediation is increasingly accepted as an effective and low-cost solution. This study aimed to evaluate the degradation of the aromatic fraction of biodiesel B10 and the soil fertility analysis in artificially contaminated soils treated with phytoremediation. The experimental design consisted of a 3x3 factorial, with three types of soil treatment: control, autoclaved, and planted with C. ensiformis L, and three levels of B10 biodiesel contamination: 0, 1, and 2%, to simulate spills of 30,000 and 60,000 L ha−1. The soil was analyzed at three depths: 0–10, 10–20, and 20–30 cm. The results indicated that aromatic compound degradation after phytoremediation was superior to 92,76% and 88,65% for 1% and 2% B10 soil contamination, respectively. The fuel contamination affected soil fertility, reducing the availability of phosphorus and zinc while increasing the Total Organic Carbon (TOC), pH, and the availability of manganese and iron for plants. NOVELTY STATEMENT: Numerous studies have been carried out on the phytoremediation of soils contaminated with diesel. However, the potential impact of biodiesel-diesel blends on soil fertility has not been fully explored, leading to a critical knowledge gap. This work investigates the novel effects of biodiesel-diesel blends on phytoremediation and soil fertility, allowing us to expand our understanding of the effectiveness of this approach to remediate contaminated sites. [ABSTRACT FROM AUTHOR]

The biochemical response of plants exposed to pesticides and inoculated with microorganisms is of great importance to explore cleaning up strategies for contaminated sites with pyrethroid-based pesticides. We evaluated the effects of a Trichoderma consortium on the biochemical responses of Echinochloa polystachya plants during the removal of a pyrethroid-based pesticide. Plants were inoculated or not with the Trichoderma consortium and exposed to commercial pesticide H24®, based on pyrethroids. Pesticide application resulted in significant reduction in root protein content (58%), but enhanced content of malondialdehyde (MDA) in shoots, superoxide dismutase (SOD) activity in shoots and roots, and catalase (CAT) activity in roots. Inoculation of Trichoderma consortium in E. polystachya exposed to the pesticide resulted in increased protein content in roots and MDA content in shoots (2-fold). Trichoderma consortium improved protein content and SOD activity (140-fold) in plants. Fungal inoculation increased the removal (97.9%) of the pesticide in comparison to the sole effect of plants (33.9%). Results allow further understanding about the responses of the interaction between plants and root-associated fungi to improving the assisted-phytoremediation of solid matrices contaminated with organic pesticides. NOVELTY STATEMENT: This original paper describes the positive role of the Trichoderma sp. consortium on favoring the removal of a pyretrhoid-based pesticide. This is one of first reports on analyzing the influence of a Trichoderma consortium on the oxidative stress and antioxidant response of Echinochloa polystachya in presence of the pesticide. This experimental approach provides a new alternative for further fungal assisted-phytoremediation of a pyretrhoid-based pesticide. [ABSTRACT FROM AUTHOR]

The issues associated with long‐screened wells (LSWs) (and open boreholes) at contaminated sites are well documented in the groundwater literature but are still not fully appreciated in practice. As established in seminal and review papers going back over three decades, the interpretation of sampling results from LSWs is challenging in the presence of vertical hydraulic gradients and borehole flow; furthermore, LSWs allow for vertical redistribution of contamination between aquifer layers. Acknowledgment of these issues has led to the development of new technologies and well designs to enable discrete‐zone monitoring (DZM), yet LSWs remain common for many reasons, for example, as multipurpose wells, for geophysical logging, and (or) as legacy installations. Despite the literature on LSWs and despite the adoption of DZM at many sites, the use of LSWs persists and the challenges of interpreting sampling results from LSWs remain. In this issue paper, we provide a conceptual overview of the problems posed by LSWs and review existing literature and past work to improve the interpretation of sampling in LSWs. We draw on experience from previous studies at the Hanford Site in eastern WA, USA, and use synthetic examples to illustrate key concepts and challenges for interpretation. A recently published analytical modeling framework is used to develop illustrative synthetic examples and demonstrate a workflow for building scientific intuition to understand issues around interpreting samples from LSWs, which is critical to effective characterization and groundwater remediation at sites with LSWs. [ABSTRACT FROM AUTHOR]

Production of green energy from landfill gas in a cogeneration system is considered optimal in terms of the use of local renewable energy resources, which in the production process generates hazardous waste. Yet, the production of renewable energy is not without environmental effects. The objective of the work was to analyse the operation of the installation for biogas energy generated at a municipal waste landfill and to carry out tests on the waste (mineral deposit) from a heat exchanger generated in the exhaust manifold of a gas engine of the cogeneration unit. The objective of the work was to test waste (mineral deposit) from the heat exchanger in the exhaust manifold of the gas engine of the cogeneration unit. The conducted research constitutes a significant contribution to the identification and classification of hazardous waste generated in a cogeneration unit powered by landfill gas. The results of the research showed that the waste contains high concentrations of ecotoxic elements, i.e. heavy metals (arsenic, chromium, copper, nickel, zinc), molybdenum, antimony, sulphates, which have carcinogenic activity. Pioneering research performed as part of the leaching test showed that the permissible concentrations were exceeded for 11 parameters in the case of storage in a hazardous waste landfill, and for 6 parameters in the case of storage in an underground hazardous waste landfill. The research and analyses performed in this work will serve as input material for defining the methods of hazardous waste disposal from the cogeneration unit. [ABSTRACT FROM AUTHOR]

The build-up of arsenic in agricultural soil through contaminated irrigational groundwater is a concern. Metagenomic analysis of such contaminated sites may provide a remarkable opportunity to extensively investigate the responses and adaptation of microbial communities to different levels of arsenic. The study focuses on the comparative analysis of microbial community composition and associated functions in paddy soil samples with a gradient of arsenic contamination (4.88 to 43.67 mg kg−1). Actinobacteria was found to dominate the bacterial phyla in all four samples with abundance ranging from 39.77% to 49.39% followed by Proteobacteria (20.71–38.24%). Whereas the fungal phylum Ascomycota (92.42–95.29%) dominated all the samples studied. In the study, bacteria were found to be abundant in the mid-level (15.89 and 24.84 mg kg−1) of arsenic, which included genera Gaiella, Nocardioides, Solirubrobacter, Microvirga, and Nitrospira. Fungi Beauveria, Talaromyces, Aspergillus, Pyrenophora, and Valsa were higher in relative abundance corresponding to soil arsenic concentration. Verticillium, previously reported for Pb, Zn, and Cd removal, was found in the soil sample with the mid-arsenic concentration (15.89 mg kg−1). The relative abundance of the arsenic metabolizing/ transport genes of native microbial communities also varied with the soil arsenic gradient, the genes arsJ, arsM, aioR, arsH, and arsC being the most affected. The study is the first report of Gaiella, Solirubrobacter, Beauveria, and Verticillium present in arsenic-contaminated soil, and further studies are required to explore their potential role in arsenic bioremediation. [ABSTRACT FROM AUTHOR]

1-Naphthylamine (1NA), which is harmful to human and aquatic animals, has been used widely in the manufacturing of dyes, pesticides, and rubber antioxidants. Nevertheless, little is known about its environmental behavior and no bacteria have been reported to use it as the growth substrate. Herein, we describe a pathway for 1NA degradation in the isolate Pseudomonas sp. strain JS3066, determine the structure and mechanism of the enzyme NpaA1 that catalyzes the initial reaction, and reveal how the pathway evolved. From genetic and enzymatic analysis, a five genecluster encoding a dioxygenase system was determined to be responsible for the initial steps in 1NA degradation through glutamylation of 1NA. The γ-glutamylated 1NA was subsequently oxidized to 1,2-dihydroxynaphthalene which was further degraded by the well-established pathway of naphthalene degradation via catechol. A glutamine synthetase-like (GS-like) enzyme (NpaA1) initiates 1NA glutamylation, and this enzyme exhibits a broad substrate selectivity toward a variety of anilines and naphthylamine derivatives. Structural analysis revealed that the aromatic residues in the 1NA entry tunnel and the V201 site in the large substrate-binding pocket significantly influence NpaA1’s substrate preferences. The findings enhance understanding of degrading polycyclic aromatic amines, and will also enable the application of bioremediation at naphthylamine contaminated sites. [ABSTRACT FROM AUTHOR]

Abstract\nNOVELTY STATEMENTLow remediation efficiency due to low bioavailability is a primary restrictive factor for phytoremediation applications. Specifically, this investigation examines whether Suaeda heteroptera Kitagawa (S. heteroptera) can be used in combination with β-cyclodextrin (β-CD) to remediate contaminated site. The study was conducted on the growth response of S. heteroptera, bioavailability and dissipation of petroleum hydrocarbons (PHs) in soil under the influence of β-CD Our preliminary studies confirmed that β-CD is effective in increasing the biomass and height of plants. The presence of β-CD could dramatically elevate polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in S. heteroptera. Moreover, a remarkable positive correlation between PHs levels in roots with the dosage of β-CD and a negative correlation between the PHs levels in roots with KOW of PHs have been observed. The dissipation of n-alkanes was estimated to be 38.73–62.27%, and the dissipation of PAHs was 36.59–60.10%. In addition, the dissipation behavior of n-alkanes and PAHs was well agreement with the first-order kinetic model. These results display that applying β-CD accelerated the desorption process of PHs from soil and promoted the absorption process of PHs onto the root epidermis. The enhancement of phytoremediation was achieved by increasing the bioavailability of PHs.There has been an increasing concern regarding soil contamination by petroleum hydrocarbons (PHs) released by industrial activities. The study attempted to investigate how β-CD affects the phytoremediation of PHs-contaminated sites. The findings of this study offer an environmentally friendly and cost-effective method of phytoremediating industrially contaminated sites using β-CD enhanced-phytoremediation. [ABSTRACT FROM AUTHOR]

Environmental contamination of aquatic systems by per‐ and polyfluoroalkyl substances (PFAS) has generated significant health concerns. Remediation of contaminated sites such as the fire‐fighting emergency training grounds that use aqueous film‐forming foams is a high priority. Phytoremediation may help play a part in removing PFAS from such contaminated waters. We investigated the potential of the water fern Azolla filiculoides, which is used for phytoremediation of a wide range of contaminants, to uptake seven common PFAS (perfluorobutanoic acid [PFBA], perfluorobutane sulfonic acid [PFBS], perfluoroheptanoic acid [PFHpA], perfluorohexanoic acid [PFHxA], perfluorohexane sulfonic acid [PFHxS], perfluorooctanoic acid [PFOA], and perfluoropentanoic acid [PFPeA]), during a 12‐day exposure to environmentally relevant concentrations delivered as equimolar mixtures: low (∑PFAS = 0.0123 ± 1.89 μmol L−1), medium (∑PFAS = 0.123 ± 2.88 μmol L−1), and high (∑PFAS = 1.39 μmol L−1) treatments, equivalent to approximately 5, 50, and 500 µg L−1 total PFAS, respectively. The possible phytotoxic effects of PFAS were measured at 3‐day intervals using chlorophyll a content, photosystem II efficiency (Fv/Fm), performance index, and specific growth rate. The PFAS concentrations in plant tissue and water were also measured every 3 days using ultra‐high‐performance liquid chromatography—tandem mass spectrometry. Treatments with PFAS did not lead to any detectable phytotoxic effects. All seven PFAS were detected in plant tissue, with the greatest uptake occurring during the first 6 days of exposure. After 12 days of exposure, a maximum bioconcentration factor was recorded for PFBA of 1.30 and a minimum of 0.192 for PFBS. Consequently, the application of Azolla spp. as a stand‐alone system for phytoremediation of PFAS in aquatic environments is not sufficient to substantially reduce PFAS concentrations. Environ Toxicol Chem 2024;00:1–12. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Phytoremediation is a promising technique to clean the noxious contaminants from soil, air and water as the pollutants like heavy metals which severely affect the environment due to anthropogenic activities. Most of pollutants de-contamination methods are costly and have low performance. Phytoremediation is effective and affordable green technology which uses selected green plants. Different plants species experimentally proven to absorb different metals like Pb, Zn, As, Cd, Cr from contaminated sites. This review focuses on development of phytoremediation of metals from environmental compartments. The aim of this review to conduct the studies on phytoremediation in Pakistan in the last two decades phytoremediation has different mechanisms such as phytoextraction, phytodegradation, phytovolatilization, phytostabilization and Rhizofiltration. In Pakistan out of 400 plant species only 50 plant species were observed to clean contaminated soil, air and water. Heavy metals contamination has become most alarming problem worldwide. A previous study revealed about 1.7 billion places are affected from heavy metals contamination especially in developing countries. Metals are non bio-degradable and tend to bio-accumulate and biomagnify in food chain and linked with many diseases, their remediation using plants is economical and environmental friendly. [ABSTRACT FROM AUTHOR]

The Arctic region has undergone warming at a rate more than 3 times higher than the global average. This warming has led to the degradation of near-surface permafrost, resulting in decreased ground stability. This instability not only poses a primary hazard to Arctic infrastructure and human-impacted areas but can also lead to secondary ecological hazards from infrastructure failure associated with hazardous materials. This development underscores the need for a comprehensive inventory of critical infrastructure and human-impacted areas. The inventory should be linked to environmental data to assess their susceptibility to permafrost degradation as well as the ecological consequences that may arise from infrastructure failure. Here, we provide such an inventory for Alaska, a vast state covering approximately 1.7 × 106 km 2 , with a population of over 733 000 people and a history of industrial development on permafrost. Our Synthesized Inventory of CRitical Infrastructure and HUman-Impacted Areas in AlaSka (SIRIUS) integrates data from (i) the Sentinel-1/2-derived Arctic Coastal Human Impact dataset (SACHI); (ii) OpenStreetMap (OSM); (iii) the pan-Arctic Catchment Database (ARCADE); (iv) a dataset of permafrost extent, probability and mean annual ground temperatures; and (v) the Contaminated Sites Database and reports to create a unified new dataset of critical infrastructure and human-impacted areas as well as permafrost and watershed information for Alaska. The integration process included harmonizing spatial references, extents and geometries across all the datasets as well as incorporating a uniform usage type classification scheme for the infrastructure data. Additionally, we employed text-mining techniques to generate complementary geospatial data from textual reports on contaminated sites, including details on contaminants, cleanup duration and the affected media. The combination of SACHI and OSM enhanced the detail of the usage type classification for infrastructure from 5 to 13 categories, allowing the identification of elements critical to Arctic communities beyond industrial sites. Further, the new inventory integrates the high spatial detail of OSM with the unbiased infrastructure detection capability of SACHI, accurately representing 94 % of the polygonal infrastructure and 78 % of the linear infrastructure, respectively. The SIRIUS dataset is presented as a GeoPackage, enabling spatial analysis and queries of its components, either as a function of or in combination with one another. The dataset is available on Zenodo at 10.5281/zenodo.8311243. [ABSTRACT FROM AUTHOR]

Sustainable remediation demonstrates that the benefit of undertaking remediation is more significant than its impact, and the optimum remediation solution is selected through a balanced decision-making process. Assessing sustainable remediation is site and project-specific and is strongly multifactorial across a wide range of categories, which may or may not be readily quantifiable. The applied socio-economic survey framework is based on the 2020 SuRF-UK guidance. The assessment was carried out in three steps. A small core team, an interim evaluation by the project of all beneficiaries, and a final assessment including the views of a broad range of external stakeholders developed an initial "pilot" sustainability assessment. The sustainability assessment process compared options across 45 individual criteria in 15 overarching "headline" categories: environmental, social, and economic. Members selected suitable criteria and the individual rankings of the project consortium from research, service providers and the site owner. The assessments compared Wetland+ with the wastewater treatment plant (WWTP) and no-intervention scenario. Wetland+ outranked the use of WWTP, and both performed significantly better than the no-intervention scenario. The quantitative data from LCA confirmed the results devoted to environmental impact. Practical Applications: Remediation of contaminated sites is site-specific, and each site requires a specific targeted approach that should take into account not only the environmental benefits of the measures but also economic and social aspects. In the case of water contaminated with hexachlorocyclohexane (HCH) substances, there are various methods of dealing with it, ranging from removal and relocation to a secure site-to-site encapsulation to various methods of contaminated water treatment. In the case of mega-sites, the solution often reduces to water treatment, as other solutions are not acceptable, especially economically, but also environmentally (transporting large volumes of materials) and socially (large construction and material handling). The present paper gives guidance on the selection of the most accepted water treatment option from a sustainability point of view. A three-step process based on a multiparametric assessment shows how the subjective approach of technologists, activists, or the public can be eliminated. The paper shows that a wetland-based solution is accepted significantly more than a WWTP or a no-action scenario. The approach will be further applied to similar localities with HCH contamination but can be generalized to a much broader set of contaminated sites. [ABSTRACT FROM AUTHOR]

• Attack from natural enemies on plants may be reduced in metal contaminated sites. • Plants may elevate defenses to simultaneously deal with enemies and metal stress. • Herbivory was lower in a copper mine than adjacent site in four of seven plant species. • Mine site plants had more physical and chemical defenses than adjacent site plants. • Hyperaccumulator species showed relatively few increased defenses in the mine. Heavy metal pollution in soil can impact the relationships between plants and their natural enemies. Enemy attack from herbivores and pathogens is predicted to be lower in metal-contaminated areas such as mine sites. However, whether this is the case is remains to be tested. It is also unknown how defense traits differ in polluted sites compared to adjacent sites. To address this gap in knowledge, we compared the standing leaf damage in populations of two invasive and five native plant species at the abandoned Jiuhua copper mine and an adjacent site. We also compared physical and chemical defense traits of the populations. Herbivory on four plant species was significantly lower in a copper mine than in an adjacent site. Overall, plants growing in the mine were more physically and chemically defended than plants growing adjacent to the mine. Copper hyperaccumulator species (Cynodon dactylon and Kummerowia stipulacea) increased defense levels in the mine for only one of the traits. In contrast, defenses were higher in the mine site for most traits relative to their respective adjacent populations in the non-hyperaccumulator species. Our results suggest that the damage herbivores inflict on plants may be strongly influenced by how plants respond to stressors in mine site environments, such as metal pollution. Metal hyperaccumulation and increased non-elemental defenses may be alternate responses used by plants to simultaneously deal with metal pollution and natural enemies in contaminated sites. [ABSTRACT FROM AUTHOR]

Few studies apply geochemical concepts governing fluoride fate and transport in natural waters to geochemical conditions at contaminated industrial sites. This has negative implications for designing sampling and compliance monitoring programs and informing remediation decision‐making. We compiled geochemical data for 566 groundwater samples from industrial waste streams associated with elevated fluoride and that span a range of geochemical conditions, including alkaline spent potliner, near‐neutral pH coal combustion, and acidic gypsum stack impoundments. Like natural systems, elevated fluoride (hundreds to thousands of ppm) exists at the pH extremes and is generally tens of ppm at near‐neutral pH conditions. Geochemical models identify pH‐dependent fluoride complexation at low pH and carbonate stability at high pH as dominant processes controlling fluoride mobility. Limitations in available thermochemical, kinetic rate, and adsorption/desorption data and lack of complete analyses present uncertainties in quantitative models used to assess fluoride mobility at industrial sites. Practitioner Points: Geochemical fundamentals of fluoride fate and transport in groundwater are communicated for environmental practitioners.Fluoride is a reactive constituent in groundwater, and factors that govern attenuation are identified.Geochemical models are useful for identifying fluoride attenuation processes, but quantitative use is limited by thermodynamic data uncertainties. [ABSTRACT FROM AUTHOR]

The present study reflects on spontaneous nature's agency to reclaim abandoned urban areas in Italian urban brownfields, providing a focused analysis of the Metropolitan Area of Milan. These spaces are the products of phenomena, such as deindustrialization, demilitarization, and uncontrolled urban expansion, which have produced a compromised heritage and challenges to regeneration. Such abandonment sometimes produces new forms of urban nature, which suggests a possible path for ecological regeneration and coexistence, as affirmed by the multidisciplinary literature. The related informal urban biodiversity grows regardless of future planning provisions, triggering unexpected transformations of the urban environment and producing socio-ecological value, as demonstrated by citizens' recognition of these places. The present study maps informal urban biodiversity in the Milan territory, identifying the presence of large contaminated sites, relevant urban voids, vacant lots, and former agricultural spaces. This study also reflects on possible paths for urban planning and policies to integrate informal urban biodiversity within the urban ecological structure by analyzing the main features and challenges of the corresponding regeneration processes. [ABSTRACT FROM AUTHOR]

Many rural people in developing countries rely on herbal remedies, but these derive from plants which may be subject to heavy metal pollutants. Lead, cadmium and arsenic are confirmed carcinogens and may produce toxic effects if present above the recommended levels in medicinal herbs. The study assessed the uptake and associated health risk of Pb, Cd and As by Euphorbia prostrata exposed to different contaminating sources. The levels of Pb were within safe limits of the World Health Organization both in soil (200 mg/kg) and plant (10 mg/kg). Cadmium concentration in soil from all sites exceeded the allowable range (0.6 mg/kg), exceeding the safe permissible limit of 0.3 mg/kg in plants growing in contaminated sites. E. prostrata and other medicinal herbs growing in polluted sites should not be used therapeutically. [ABSTRACT FROM AUTHOR]

Theoretically grounded in queer death studies and environmental humanities, this article has a twofold aim. Firstly, it explores the somatechnics of environmental violence in the context of Northern and Eastern Europe, while paying attention to ongoing ecocide inflicted by Russia on Ukraine, and to the post-WW2 chemical weapon dumps in the Baltic Sea. Secondly, the article examines the concept of eco-grief in its close relation to artistic narratives on ecocide. By bridging the discussion on environmental violence and artistic renderings of eco-grief, the article hopes to contribute to a better understanding of the socio-cultural responses to more-than-human death and loss, and their accompanying ethical imaginaries and affordances. [ABSTRACT FROM AUTHOR]

The burden of autism spectrum disorder (ASD) is increasing worldwide with genetic, epigenetic, and environmental factors being possibly responsible for the observed epidemiological figures. In the setting of environmental exposure, the city of Taranto, in Southern Italy, represents an interesting case study as it hosts well inside the city one of the biggest steel plants in Europe. This is a cross-sectional ecological study carried out in the year 2020 in the province of Taranto designed to estimate the burden of ASD in the municipalities of Taranto and Statte, classified as high environmental risk areas (Contaminated Site of National Interest—SIN), compared to the other 27 municipalities of the same province. Differences have been evaluated using the Chi Square Test. Children aged 6–11 years identified in SIN municipalities had a statistically significant higher prevalence of ASD than children of other municipalities (9.58 vs. 6.66/1000 respectively, p = 0.002). No statistically significant difference was observed for the 12–18 years group (3.41 vs. 2.54/1000, p = 0.12). The findings observed in this study are suggestive of the association between urban residential proximity to industrial facilities emitting air pollutants and higher ASD prevalence. [ABSTRACT FROM AUTHOR]

For contaminated sites, conceptual site models (CSMs) guide the assessment and management of risks, including remediation strategies. Recent research has expanded diagrammatic CSMs with structural causal modeling to develop what are nominally called conceptual Bayesian networks (CBNs) for environmental risk assessment. These CBNs may also be useful for problems of controlling and preventing offsite contaminant migration, especially for sites containing dense nonaqueous phase liquids (DNAPLs). In particular, the CBNs provide greater clarity on the causal relationships between source term, onsite and offsite migration, and remediation effectiveness characterization for contaminated DNAPL sites compared to traditional CSMs. These ideas are demonstrated by the inclusion of modifying variables, causal pathway analysis, and interventions in CBNs. Additionally, several new extensions of the CBN concept are explored including the representation of measurement variables as lines of evidence and alignment with conventional pictorial CSMs for groundwater modeling. Taken as a whole, the CBNs provide a powerful and adaptable knowledge representation tool for remediating subsurface systems contaminated by DNAPL. [ABSTRACT FROM AUTHOR]

Phytoremediation is an in situ remediation and eco-friendly technique employing accumulator plant species to remove trace elements (TEs) from contaminated sites. Moreover, it has been demonstrated that both natural and synthetic amendments can enhance trace elements (TEs) phytoremediation from polluted soils through bioenergy crops. This work assessed the synergistic impact of two tested biochar (BC) from data palm (B1) and Prosopis (B2) (1.5%/ kg), citric acid (CA, 1.5 mmol/kg) and vermiwash (VW, 20 ml/kg) to enhance the remediation of tested TEs (Mn, Zn, Cd, Pb, Ni, Cu, and Fe) from Mahad AD'Dahab mine-contaminated soil by sorghum (Sorghum bicolor L.). The BC and CA amendments alone and combined with VW significantly augmented the proliferation and survival of sorghum grown in mine-contaminated soil. Considering the individual and combined applications of VW and BC, the influence on plant growth followed this order: K < VW < B2 < B1 < B1 + VW < B2 + VW < CA < CA + VW. Applying tested BC/CA and VW significantly increased chlorophyll compared to unamended soil. The outcomes revealed a substantial elevation in TE absorption in both shoot and root (p ≤ 0.05) with all tested treatments compared to the untreated soil (K). The combined application of CA and VW resulted in the most significant TE uptake of TEs at both the root and the shoot. Furthermore, adding CA or VW as a foliar spray enhanced the bioaccumulation factor (BCF) and translocation factor (TF) of studied metals. The combined addition of CA and foliar spraying of VW was more effective than the sole addition of CA or VW. Such increase reached 20.0%, 15.6%, 19.4%, 14.3%, 14.0%, and 25.6% of TF, and 13.7%, 11.9%, 8.3%, 20.9%, 20.5%,18.7%, and 19.8% of BCE for Cd, Cu, Fe, Mn, Ni, Pb, and Zn, respectively. This study highlights the efficiency of combining CA/BC with VW as a more viable option for remediating mine-contaminated soil than individual amendments. However, future research should prioritize long-term field trials to assess the efficiency of using citric acid and vermiwash for restoring contaminated mining soils. [ABSTRACT FROM AUTHOR]

The diagnosis and monitoring of contaminated sites have become progressively critical. The effectiveness of electrical resistivity tomography (ERT) has been demonstrated in the assessment of contaminated sites, and its resolution can be significantly improved by array optimization. Gradient array involves the deployment of multiple electrodes in an array configuration to measure the variation in electrical potential across the subsurface, whereas there are some improved arrays which can often provide more accurate measurements. This study investigates the conventional gradient and improved Compare Resolution protocol to identify an abandoned quarry pit where pharmaceutical wastes were dumped. The acquired results were subsequently validated with borehole sampling. The results obtained from the gradient protocol revealed the presence of low-resistivity area. Nevertheless, it is difficult to define the range of the contamination plume area. The results from the optimized array illustrated that the maximum lateral contamination range in the vertical direction appears at a depth of 9 m. A portion of the contaminated area shown in the profile is confined by bedrock. Considering the high cost, only four locations are chosen for drilling to collect samples. The findings revealed that low resistivity corresponds to contamination of inorganic substances. The resistivity and drilling results further clarify that the site has a three-layer structure. The spatial variability of the contaminated site has been ascertained by the high-resolution ERT, and further identify four contaminant sources. This study proves the effectiveness of the ERT method to avoid the drawbacks of costly drilling in bedrock and accomplishes an efficient assessment of contamination. [ABSTRACT FROM AUTHOR]

Soil-bentonite (S-B) barriers have been widely used for heavy metal pollution containment. This study conducted batch adsorption tests and diffusion-through tests to evaluate how ionic strength and bentonite ratio influence the migration of Cr(VI) in natural clay-bentonite mixtures. The test results indicated that the adsorption of Cr(VI) exhibited an obvious anion adsorption effect, the pH of the soil mixture increased with the addition of bentonite, resulting in a decrease in the positive surface charge. This change led to a decrease in Cr(VI) adsorption capacity, from 775.19 mg/kg for pure clay to 378 mg/kg for mixture samples with excessive bentonite. Furthermore, as the ionic strength increases from 0 to 0.1 M, the Cr(VI) adsorption capacity increases slightly due to the weakening of electrostatic repulsion on the clay particle surface, but the effective diffusion coefficient (De) increases by 21.97%. The compression of the diffusion double layer (DDL) under high ionic strength conditions enlarges the diffusion path and enhances the migration of Cr(VI) through the pore flow paths. Moreover, hydrated bentonite effectively fills the interaggregate pores of natural clay, thus creating narrower and more tortuous flow paths. However, excessive bentonite increases the pH value and pore volume, resulting in changes to the soil microstructure and disrupting the continuous skeleton of natural clay, which is unfavorable for Cr(VI) containment. Based on the study of the Cr(VI) contaminated site, a bentonite ratio of 2:10 is recommended for optimal natural performance of the natural clay-bentonite barrier. [ABSTRACT FROM AUTHOR]

Almost all research on natural attenuation and phytoremediation of sites contaminated with briny produced water has been conducted in temperate climates, however, there is a dearth of information on the use of tropical species for this purpose. It is within this context, that we investigated a spontaneously growing hypersaline spikerush from a contaminated site in southeast Mexico, to determine its soil salinity limits, the relationship between soil organic matter and salinity, and for preliminary documentation of floristic succession with Typha sp. for phytoremediation o f brine s pills. Soil was sampled (0 cm–20 cm) three times between 2018–2021, focusing on the end of the dry season (most critical period). The species tentatively identified as Eleocharis mutata was tolerant to soil hypersalinity (Electrical Conductivity: 125 dS/m) and appeared to generate a cyclic process of succession to recover areas with soil salinity levels higher than it could otherwise tolerate. A salinity gradient was found between the most heavily contaminated part of the site (“kill zone”, > 212 dS/m), the first Eleocharis sp. individuals (125 dS/m), slowly advancing through the main spikerush stand, and finally into a cattail stand (< 8.02 dS/m). Similarly, an inverse relationship between Soil Organic Matter content and soil salinity was observed. This is the first time this species has been identified with a brine spill, its salinity limits determined, and investigated for use in phytoremediation of this kind. [ABSTRACT FROM AUTHOR]

We examined the spatial concentration of public housing, demographic indicators of low socioeconomic status, and environmental locally unwanted land uses (LULUs) in eight populous U.S. cities. Using the updated EJScreen database and its geographic information systems capabilities, we, as expected, found subsidized housing to be disproportionately colocated in areas with poor and underserved residents. Underground storage tanks and high traffic density were consistently associated with the location of public housing, whereas Superfund sites were located near public housing in only half of the cities in the study. Increasing our understanding of the variables typically used to measure environmental and social justice is important to expand the discussion around a broader set of environmental measures that might be more relevant to the communities that live near them without ignoring the traditional ones that have marked the early legacy of the environmental justice movement. [ABSTRACT FROM AUTHOR]

The current study attempted to develop a bacterial consortium which can degrade chlorpyrifos pesticide efficiently. Five morphologically different bacterial strains, capable to tolerate high chlorpyrifos concentration, were isolated from pesticide-contaminated soil. Further, possible combinations of the isolates were formed and each combination was screened and chlorpyrifos degradation percentage and half-lives were calculated. The consortium CON11, comprising of four isolates (CP28, CP30, CP31, and CP34) showed the highest chlorpyrifos degradation. The individual independent variables of chlorpyrifos degradation by CON11 viz. temperature (°C), pH, incubation time (days) and pesticide concentration (ppm) were optimized using one-factor at-a-time experiments. The consortium isolates were then identified by the molecular tools 16S rRNA gene typing and the sequences were submitted to GenBank. The four bacterial isolates thus identified are Bacillus amyloliquefaciens CP28 (MH667455), Bacillus pumilus CP30 (MH667456), Bacillus marisflavi CP31 (MN715880), and Bacillus subtilis CP34 (MH667458). These isolates which comprise CON11 consortium could degrade 91% of 100 ppm chlorpyrifos after 6 days of incubation at 30 °C and pH 7 with a half-life of 1.73 days indicating the promising potential of the consortium, CON11, in the cleanup of chlorpyrifos contaminated sites. [ABSTRACT FROM AUTHOR]

Heavy metal-enriched fly ash (FA) deposits are recognized as hazardous contaminated sites on the earth, which pollute our ecosystems. Consequently, the present investigation was carried out to explore the phytoremediation potential of naturally growing medicinal plants in the FA dumpsite. This present study chose two native medicinal plants i.e., Bacopa monnieri and Acmella oleracea found to be naturally colonizing abundantly on FA dumpsite to assess heavy metal accumulation. FA sample of B. monnieri thriving sites found to have metal content in order Mn (216.6)> Cr (39.27)> Zn (20.8)> Ni (16.1)> Cu (15.03)> Co (6.7)> Pb (5.43) whereas for A. oleracea FA dumpsites, the order of metal availability was Mn (750.3)> B (54.5)>Cr (37.2)>Zn (31.33)> Cu (18.7)> Ni (16.93)> Co (7.7)>Pb (4.23). In B. monnieri, higher concentrations of Cr and Mn were observed in the shoot in comparison to the root, indicative of its potential as a hyperaccumulator plant. Conversely, in A. oleracea, greater amounts of Pb were detected in the shoot relative to the root. Hence, it is recommended that B. monnieri and A. oleracea grow on such heavy metal-enriched substrates should be avoided for medicinal purposes; however, these plants can be used for phytoremediation purposes. Fly ash phytoremediation through natural colonizer plant species is limited. Native colonizing plant species on fly ash has a pivotal role in phytoremediation. Naturally colonizing medicinal plants were dominant over the Fly ash dumpsites. Bacopa monnieri and Acmella oleracea have phytoremediation potential on fly ash. Indeed, fly ash-grown medicinal plants should not be used by local communities. [ABSTRACT FROM AUTHOR]

Heavy metal poisoning is the most prevalent health hazard at hazardous waste sites, affecting a large population on daily basis, with arsenite poisoning ranking third in terms of prevalence and severity. Therefore, the main objective of this study is to develop a novel, highly efficient sensor for detecting trace amounts of arsenite (AsIII) in human serum by utilising reduced graphene oxide/gold nanoparticles (rGO/AuNPs) based nanocomposite structure. In this work, a screen-printed carbon electrode (SPE) was modified using rGO/AuNPs nanocomposite to detect AsIII in human serum. The detection data were recorded and analysed using Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV), whereas transmission electron microscope (TEM), scanning electron microscope (SEM) as well as Fourier transform infrared (FTIR) spectroscopy were used to determine the surface morphological features and the presence of significant elements/groups in the prepared nanocomposite structure. Under the optimised conditions, the linear regression coefficient (R2) for the DPV response of the fabricated electrode (rGO/AuNPs@SPE) was observed to be 0.98. The rGO/AuNPs@SPE demonstrated remarkable sensor response for AsIII with detection limits of 10 ppb via DPV in standard samples, due to the synergistic effect of rGO and AuNPs based nanocomposite. The sensitivity of the sensor was found to be 0.0142 Appb−1cm−2 for 100–1000 ppb concentration range of AsIII. The rGO/AuNPs@SPE sensor also displayed good stability and reproducibility when used in AsIII spiked human serum samples in which the limit of detection was observed at 100ppb. The porous structure of rGO on the sensing interface efficiently improves the electrode's adsorption and conductivity, while citrate capped AuNPs offer the functional groups required for maximum adsorption of AsIII. Hence, the developed electrochemical sensor (rGO/AuNPs@SPE) can be used very precisely and reliably in various applications for trace level detection of AsIII in human serum. [ABSTRACT FROM AUTHOR]

This document provides a calendar of upcoming events in the plastic film and sheeting industry, including conferences, symposiums, and webinars from September 2024 to March 2025. These events cover a wide range of topics such as coating science, foams, thermoplastics, additives, and sustainability. The document also includes information on process safety, including recent bulletins from the American Institute of Chemical Engineers and a report from the U.S. Chemical Safety Board on a fatal well blowout incident in Texas. The U.S. Chemical Safety and Hazard Investigation Board (CSB) is currently investigating two toxic chemical incidents in Louisiana in 2023, aiming to identify the causes and develop safety recommendations. DuPont has announced plans to separate its Water Solutions business into a standalone company, which focuses on providing clean water across various market segments. The separation is expected to be completed within 18 to 24 months and will not require a shareholder vote. The new company is expected to have a strong financial position and maintain an investment grade credit rating. [Extracted from the article]

Industrial activities have historically generated significant quantities of by-products, including pyrite cinders, a residue produced during the synthesis of sulphuric acid. This study presents a multidisciplinary approach to characterise an abandoned pyrite cinder deposit. Combining geophysical (electrical resistivity tomography—ERT), geochemical, and statistical methods, we assess the physicochemical properties of the deposit and its environmental implications. Our findings reveal the presence of heavy metals, with lead (7017.5 mg.kg−1) being the most concentrated element on the surface of the deposit, exceeding local legal thresholds by more than 163 times, posing environmental risks and inhibiting vegetation growth. Subsurface characterisation indicates a decreasing concentration trend of metals with depth, alongside variations in pH and electrical conductivity. Clustering analysis identifies groups of similar behaviours between resistivity, the most abundant heavy metals, and other variables, providing valuable insights into the complex interplay within the deposit. Our study underscores the importance of integrated approaches in assessing and managing hazardous waste sites, with implications for environmental remediation strategies. [ABSTRACT FROM AUTHOR]

With the soaring generation of hazardous waste (HW) during industrialization and urbanization, HW illegal dumping continues to be an intractable global issue. Particularly in developing regions with lax regulations, it has become a major source of soil and groundwater contamination. One dominant challenge for HW illegal dumping supervision is the invisibility of dumping sites, which makes HW illegal dumping difficult to be found, thereby causing a long-term adverse impact on the environment. How to utilize the limited historic supervision records to screen the potential dumping sites in the whole region is a key challenge to be addressed. In this study, a novel machine learning model based on the positive-unlabeled (PU) learning algorithm was proposed to resolve this problem through the ensemble method which could iteratively mine the features of limited historic cases. Validation of the random forest-based PU model showed that the predicted top 30% of high-risk areas could cover 68.1% of newly reported cases in the studied region, indicating the reliability of the model prediction. This novel framework will also be promising in other environmental management scenarios to deal with numerous unknown samples based on limited prior experience. [ABSTRACT FROM AUTHOR]

Noccaea praecox and Noccaea caerulescens (Brassicaceae) are nickel and zinc hyperaccumulators, native to Europe. To date, most studies have focused on metal accumulation in the leaves, whereas the distribution of metals in the inflorescences of hyperaccumulator plants remains largely unexplored, but of great interest in the context of adaptation to fertility and (insect) pollination. Samples of N. praecox from an ultramafic site and N. caerulescens from an industrially contaminated site were used for synchrotron‐based micro‐X‐ray fluorescence (μXRF) analysis. The results showed that nickel and zinc in the flowers of N. praecox are mainly distributed in the receptacle, ovary, and anthers, but at different concentrations. Similar results were found in N. caerulescens, with the greatest accumulation in the receptacle and ovary, especially in the walls, however at lower levels in the anthers. Although the leaves of N. praecox and N. caerulescens are the main deposition sites for nickel and zinc, significant concentrations of these elements were deposited in the flowers, especially in the pistils and anthers, indicating possible negative effects on fertility and pollinator species. [ABSTRACT FROM AUTHOR]

A static batch test was used to determine the optimal ratio of Fenton’s reagent for removing benzene and toluene from contaminated subsurface at a site, followed by a two-dimensional simulation tank experiment, where benzene and toluene were distributed throughout the tank, and then in the groundwater circulation wells. The Fenton’s reagent of 0.05 L of 3% H2O2 and 6.12 g of FeSO4·7H2O was added in the ratio of 0.05 L of 3% H2O2 and 6.12 g of FeSO4·7H2O, and the reactive circulation wells were initiated at an aeration rate of 15 L/min.The results show:The groundwater circulation close to the circulation wells is highly disturbed, the mass transfer between the gas and water phases is strong, benzene and toluene are preferentially removed, and a remediation area centered on the circulation wells is gradually formed; after 12 h of cumulative aeration, contaminants within a 50 cm radius from the circulation well were below the detection limit. Residual benzene and toluene were concentrated in the area on both sides of the simulation tank, away from the circulation well. The contaminant removal efficiency within the 50-cm radius of influence of the circulation wells was high, and the enhanced remediation of benzene- and toluene-contaminated groundwater by reactive circulation wells using Fenton’s reagent as the remediation agent was more effective. [ABSTRACT FROM AUTHOR]

Aquatic ecosystems are often impacted by a multitude of stressors, many of which are introduced by a combination of anthropogenic activities such as agricultural development, urbanization, damming, and industrial discharge. Determining the primary stressors responsible for ecological impairments at a site can be complex and challenging; however, it is crucial for making informed management decisions. Improper diagnosis of an impaired system can lead to misguided attempts at remediation, which can be both time consuming and costly. We focused on the development, implementation, and evaluation of methodologies that, in combination, allowed us to identify the primary stressors. These included a four‐phase, weight‐of‐evidence (WOE) assessment including in situ Toxicity Identification and Evaluation (iTIE) testing, physicochemical and macrobenthos characterization, reciprocal sediment transplants, and laboratory and in situ toxicity testing. The contaminants of concern (COCs) at the site were elevated levels of ammonia, chloride, pH, and total dissolved solids in groundwater upwellings into a high‐quality waterway. Reciprocal transplants of site sediments and nearby reference sediments and traditional benthic sampling showed impaired benthic indices and multiple stations around a contaminated industrial settling basin. Impaired stations had elevated COCs in groundwaters but exhibited a steep vertical concentration gradient, with concentrations decreasing near the sediment–surface water interface. We describe Phase 4 of the study, which focused on teasing out the role of dissolved oxygen sags in benthic macroinvertebrate responses. Extensive submerged and emergent macrophytes, algae, and cyanobacteria co‐occurred at the impaired sites and increased throughout the summer. Laboratory testing suggested that ammonia and pH were possibly toxic at the sites, based on groundwater concentrations. The in situ toxicity testing, however, showed toxicity occurring even at stations with low levels of COCs concurrently with large diurnal fluxes in dissolved oxygen (DO). A final phase using a type of iTIE approach utilized limnocorrals with and without aeration and with in situ toxicity measures using Hyalella azteca. The Phase 4 assessment revealed that low DO levels were primarily responsible for impaired benthic communities, and COC upwellings were diluted at the sediment–water interface to nontoxic levels. These findings will allow for improved management decisions for more efficient and effective restoration activities. Environ Toxicol Chem 2024;43:1524–1536. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Containment of hazardous waste is one of the methods that can be used today for its disposal worldwide, especially in landfills. In order to preserve groundwater, landfills are constructed on a natural or reconstituted clay layer of low permeability, known as a passive safety barrier. This paper presents an experimental laboratory study that aims to upgrade local materials for use as a passive barrier in the bottoms of hazardous waste storage facilities (HWSCs). The basic materials are clays from the Adrar region in southern Algeria. An experimental study based on physical-chemical characterization and mechanical tests was performed on 2 samples of clayey soils (AA, Adrar clay, and AB, Bouda clay). Physico-chemical and mechanical characterization of Adrar clay (AA) mixtures with lime was conducted to minimize swelling and improve the studied soil. The permeability criterion allowed the adoption of an optimal mixture of Adrar clay + 6 % lime for a permeability lower than 10-12 m/s. [ABSTRACT FROM AUTHOR]

CuFeO2 nanoparticles were decorated on biochar by one-step hydrothermal method to form the CuFeO2 /BC catalyst for persulfate (PS) activation and application of CuFeO2/BC in sulfadiazine (SDZ) contaminated soil was explored in this study. The influence of some key factors such as catalyst doses, PS concentration, initial pH and different soil types on degradation of SDZ were investigated. The results showed that CuFeO2/BC system has better catalytic performance and PS utilization efficiency compared with the pure CuFeO2. Under the condition of CuFeO2/BC dosage of 8 g/kg and PS addition of 3 g/kg, 91.72% SDZ (initial concentration of 20 mg/kg) could be removed from the soil within 120 minutes. Furthermore, the mechanism of the CuFeO2/BC/PS system was revealed by quenching experiments and electron paramagnetic resonance (EPR) tests. It demonstrated that active species (SO4•-, HO•, O2•-) were involved in SDZ degradation, the weak EPR signal confirmed the existence of 1O2 but not participated in the degradation of SDZ. The steady-state concentrations of HO• and SO4•- were calculated by using free radical probes. Afterwards, the contribution rates of SO4•-, HO•, O2•- to the degradation of SDZ were obtained to be 43.89%, 32.87%, and 23.24%, respectively. Combined X-ray photoelectron spectroscopy revealed that the high catalytic efficiency was attributed to the synergistic effect of Cu+/Cu2+ and Fe2+/Fe3+ redox cycles. These findings help to achieve more comprehensive understanding of the heterogeneous activation process of PS by CuFeO2 /BC to degrade SDZ in actual contaminated sites. [ABSTRACT FROM AUTHOR]

While in situ toxicity testing with caged organisms has been used to assess surface water and sediment contamination, no successful application to benthic organisms exposed to highly contaminated groundwater plumes discharging to surface waters has been reported. The objective of this study was to demonstrate and evaluate this application using four sets of tests performed at three previously reported contaminated groundwater sites, which include one river site affected by volatile organic contaminant plumes, and two sites, one pond and one small urban stream, impacted by landfill plumes. The study examined multiple cage designs and orientations and two test organisms: an amphipod (Hyalella azteca) and midge larvae (Chironomus riparius; only one study). Cages were deployed for between 5 and 28 days and assessed for organism survival and growth. At all sites and for some deployment conditions, cages exposed to high contaminant concentrations in the plume footprint had greater mortality compared to those exposed to lower or background concentrations. Organism growth was less clear as a metric of toxicity. Vertically oriented cages typically showed high mortality to plume contaminants, but some were also affected by other non-target groundwater conditions (e.g., low dissolved oxygen, other contaminant sources), while horizontally oriented cages were rarely responsive to either groundwater influence. A hybrid cage design showed much promise in its single study. Useful observations on the test organisms and on potentially problematic site conditions were also made. The informed use of in situ toxicity cages could be an additional beneficial tool for groundwater contaminated site assessments. [ABSTRACT FROM AUTHOR]

Complex mixtures of chemicals present in groundwater at legacy-contaminated industrial sites can pose significant risks to adjacent surface waters. The combination of short-term molecular and chronic apical effect assessments is a promising approach to characterize the potential hazard of such complex mixtures. The objectives of this study were to: (1) assess the apical effects (survival, growth, development, and liver histopathology) after chronic exposure of early life stages (ELSs) of fathead minnows (FHM; Pimephales promelas) to contaminated groundwater from a legacy-contaminated pesticide manufacturing and packaging plant, and (2) identify possible molecular mechanisms responsible for these effects by comparing results to mechanistic outcomes previously determined by a short-term reduced transcriptome assay (EcoToxChips). This study revealed a significant increase in mortality and prevalence of spinal curvatures, as well as a significant reduction in the length of FHMs exposed to the groundwater mixtures in a concentration-dependent manner. There was an increasing trend in the prevalence of edema in FHMs, though not significantly different from controls. Additionally, no histopathological effects were observed in the liver of FHMs exposed to the groundwater mixtures. Short-term molecular outcomes determined in a parallel study were found to be informative of chronic apical outcomes, including cardiotoxicity, spinal deformities, and liver toxicity. Overall, the results observed in this study demonstrated that short-term transcriptomics analyses could support the hazard assessment of complex contaminated sites. Molecular outcomes were reflective of mortality and deformities, but uncertainties remained in the prediction of hepatotoxic effects at apical level. [ABSTRACT FROM AUTHOR]

Nano zero-valent iron (nZVI) acting as a high-cost disposable material in soil Cr(VI) remediation faces significant challenges due to its easily oxidizable nature and biological toxicity. In addressing this issue, the present study undertook the synthesis of a series of modified nZVI and combined the selected material with Cr(VI)-resistant filamentous fungus Penicillium oxalicum SL2 for real-site chromium pollution remediation. Adsorption experiments demonstrated that the inclusion of carboxymethyl cellulose (CMC) significantly enhanced the adsorption capacity of nZVI for Cr(VI) by 19.3% (from 73.25 to 87.4 mg/L), surpassing both biochar (37.42 mg/L) and bentonite modified nZVI (48.03 mg/ L). Characterization results validated the successful synthesis of the nano composite material. Besides, oxidative stress analysis explained the unique detoxification effects of CMC on SL2, acting as a free radical scavenger and isolating layer. In real-sites soil remediation experiments, a low dosage (0.4% w/ w) of nZVI/CMC@SL2 (CMC modified nZVI combined with SL2) exhibited an impressive reduction of over 99.5% in TCLP-Cr(VI) and completely transformed 18% of unstable Cr to stable forms. Notably, nZVI/CMC demonstrated its capability to facilitate SL2 colonization in highly contaminated soil and modulate the microbial community structure, enriching chromium-removing microorganisms. In summary, the synergistic system of nZVI/CMC@SL2 merges as a cost-effective and efficient approach for Cr(VI) reduction, providing meaningful insights for its application in the remediating contaminated site soils. [ABSTRACT FROM AUTHOR]

Human health risks associated with the consumption of water from groundwater sources in the vicinity of dumpsites in Orogwe, Nekede, and Ihiagwa in Owerri West were investigated for adults and children in this study. Groundwater samples were collected within 50-500 meters from solid waste dumpsites and subjected to In-situ analysis for fast-changing parameters such as temperature, pH, electrical conductivity, dissolved oxygen, and total dissolved solids using a Hanna multi-meter Probe. Heavy metals were measured using an Atomic absorption spectrophotometer while other parameters were examined using the American Public Health Association Method (APHA). Low pH levels were observed in the study area for wet and dry seasons. Conductivity levels and dissolved solids showed higher mean values in the wet season than dry season. The pollution index result was significant (=1) for Nekede and Ihiagwa in the dry season. Exposure doses were higher in children than adults while the non-carcinogenic results ranged from medium to high risk in all samples except the control point in the wet season. Nickel, iron, and lead had a high percentage contribution to the hazard risks in both seasons. Significant carcinogenic risk (>1.0E-4) for children recorded at Ihiagwa in the dry season is of great concern. In general, the groundwater quality in the vicinity of dumpsites was of poor quality (>100) and more vulnerable in the wet season than the dry season from the water quality index (WQI) result. [ABSTRACT FROM AUTHOR]

At the Gowanus Canal Superfund site in Brooklyn, New York, a multilayer reactive capping system is required as part of the approved remedy. The base reactive layer is an organoclay (OC)–sand layer containing a minimum of 25% by dry weight OC that is intended to block any upwelling mobile nonaqueous phase liquids (NAPLs). The construction quality assurance (CQA) method for verifying the OC content of the OC–sand stockpiles prior to placement in the canal consists of Loss on Ignition (LOI) testing performed at an offsite laboratory with a turnaround time of 3 days. To mitigate construction delays, rapid field testing methods to verify the OC content of the OC–sand blends were sought. Interestingly, electrical conductivity (EC) measurements on the as-is (not sieved or pulverized) OC, sand, and their blends provided several correlations with goodness of fit (R2) values >0.95 for a variety of sand-sized materials including: a commercial playground sand, beach sand, a limestone quarry sourced sand, and the sediment capping sand from the first Remedial Target Area (RTA-1) at the Gowanus Canal. The correlation curves and R2 values were relatively insensitive to change in the sand borrow source (silicate or karst geology or salinity). EC measurements were available in as little as 30 min and up to approximately 24 h using a tabletop pH/EC probe, distilled water, beaker, and magnetic stirrer. The EC approach and preliminary correlations presented here can greatly reduce CQA testing turnaround times to within hours (not days) in field settings. Lastly, similar findings were made when another commercially modified bentonite clay known as Fluorosorb-400™ was blended with playground sand. [ABSTRACT FROM AUTHOR]

The rupture of the Fundão dam (Brazil) spread tailings contaminated with sodium and ether-amine into the Doce River Basin. Aiming at rehabilitating a contaminated riparian site, phytoremediation with native species of the Atlantic Forest was performed under four treatments: ES-1: physical remediation (sediment scraping) + chemical remediation (organic matter) + bioremediation (double inoculation with the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis and the plant growth-promoting bacteria Bacillus subtilis); ES-2: chemical remediation + bioremediation; ES-3: physical remediation + chemical remediation; ES-4: chemical remediation. Ether-amine and sodium contents, plant growth and, soil quality parameters were compared among treatments and relative to preserved and degraded sites. Two years after planting, the outstanding plant growth was attributed to the phytoremediation of ether-amine and ammonium, followed by a significant increase in soil microbial biomass (Phospholipid fatty acids-PLFAs), particularly the Gram+ bacteria and total fungi but not AMF, whose response was independent of the inoculation. While sodium and ether-amine declined, soil K, P, NO3− contents, dehydrogenase and acid phosphatase activities, cation exchange capacity (CEC) and soil aggregation increased, especially in ES-1. Thus, such remediation procedures are recommended for the restoration of riparian areas affected by the Fundão tailings, ultimately improving sediment fertility, aggregation and stabilization. To the best of our knowledge, this is the only successful example of fragment of riparian Atlantic Forest successfully rehabilitated using native trees from the Atlantic Forest in the riparian zone affected by the contaminated Fundão dam tailings. For that, phytoremediation and bioremediation procedures were adopted to alleviate etheramine and sodium toxicity, resulting in the amelioration of soil fertility and particularly the stabilization of such highly disaggregated sediments, ultimately protecting the Doce river basin against these contaminants. [ABSTRACT FROM AUTHOR]

There are scarce data regarding the effects of soil amendments on biophysicochemical responses of plants at the early stages of growth/germination. This study critically compares the effects of ethylene-diamine-tetra-acetic-acid (EDTA) and calcium (Ca) on biophysicochemical responses of germinating pea seedlings under varied arsenic levels (As, 25, 125, 250 µM). Arsenic alone enhanced hydrogen peroxide (H2O2) level in pea roots (176%) and shoot (89%), which significantly reduced seed germination percentage, pigment contents, and growth parameters. Presence of EDTA and Ca in growth culture minimized the toxic effects of As on pea seedlings, EDTA being more pertinent than Ca. Both the amendments decreased H2O2 levels in pea tissues (16% in shoot and 13% in roots by EDTA, and 7% by Ca in shoot), and maintained seed germination, pigment contents, and growth parameters of peas close to those of the control treatment. The effects of all As-treatments were more pronounced in the pea roots than in the shoot. The presence of organic and inorganic amendments can play a useful role in alleviating As toxicity at the early stages of pea growth. The scarcity of data demands comparing plant biophysicochemical responses at different stages of plant growth (germinating vs mature) in future studies. Till date, abundant research has focused on plant biophysicochemical responses to different types of pollutants. However, the majority of these studies dealt with pollutant exposure to mature plants (generally after a vegetative growth period of 1–2 weeks). Despite significant research, there are still limited data regarding the biophysicochemical responses of plants at their early stages of germination and growth. In fact, stresses at germination or at an early stage of growth can be highly fatal and may significantly affect the ultimate plant growth and potential to remediate the contaminated sites. Therefore, the current study deals with the exposure of germinating pea seedlings to arsenic (As) stress under varied amendments. This experimental plan helped to understand the initial biophysicochemical changes induced in pea plants under As stress. [ABSTRACT FROM AUTHOR]