Environments

19 pages, 1851 KiB

Open AccessArticle

Industrial-Scale Wastewater Nano-Aeration and -Oxygenation and Dissolved Air Flotation: Electric Field Nanobubble and Machine Learning Approaches to Enhanced Nano-Aeration and Flotation

by Niall J. English

Environments 2025, 12(7), 228; https://doi.org/10.3390/environments12070228 (registering DOI) - 5 Jul 2025

Abstract

Substantial boosts in the low-energy nano-oxygenation of incoming process water were achieved at a municipal wastewater treatment plant (WWTP) upstream of activated sludge (AS) aeration lanes on a single-pass basis by means of an electric field nanobubble (NB) generation method (with unit residence [...] Read more.

Substantial boosts in the low-energy nano-oxygenation of incoming process water were achieved at a municipal wastewater treatment plant (WWTP) upstream of activated sludge (AS) aeration lanes on a single-pass basis by means of an electric field nanobubble (NB) generation method (with unit residence times of the order of just 10–15 s). Both ambient air and O₂ cylinders were used as gas sources. In both cases, it was found that the levels of dissolved oxygen (DO) were maintained far higher for much longer than those of conventionally aerated water in the AS lane—and at DO levels in the optimal operational WWTP oxygenation zone of about 2.5–3.5 mg/L. In the AS lanes themselves, there were also excellent conversions to nitrate from nitrite, owing to reactive oxygen species (ROS) and some improvements in BOD and E. coli profiles. Nanobubble-enhanced Dissolved Air Flotation (DAF) was found to be enhanced at shorter times for batch processes: settlement dynamics were slowed slightly initially upon contact with virgin NBs, although the overall time was not particularly affected, owing to faster settlement once the recruitment of micro-particulates took place around the NBs—actually making density-filtering ultimately more facile. The development of machine learning (ML) models predictive of NB populations was carried out in laboratory work with deionised water, in addition to WWTP influent water for a second class of field-oriented ML models based on a more narrow set of more easily and quickly measured data variables in the field, and correlations were found for a more facile prediction of important parameters, such as the NB generation rate and the particular dependent variable that is required to be correlated with the efficient and effective functioning of the nanobubble generator (NBG) for the task at hand—e.g., boosting dissolved oxygen (DO) or shifting Oxidative Reductive Potential (ORP). Full article

(This article belongs to the Special Issue Advanced Catalytic Processes and Nanomaterials for Environmental Remediation)

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23 pages, 6122 KiB

Open AccessArticle

Decoding Salinization Dynamics in Mediterranean Coastal Aquifers: A Case Study from a Wetland in Southern Italy

by Giuseppe Passarella, Rita Masciale, Matia Menichini, Marco Doveri and Ivan Portoghese

Environments 2025, 12(7), 227; https://doi.org/10.3390/environments12070227 - 2 Jul 2025

Abstract

This study investigates the salinization processes affecting the coastal aquifer within the Torre Guaceto State Nature Reserve, a Mediterranean coastal area characterized by a unique ecological value of a brackish wetland threatened by water-intensive agricultural activities. Groundwater salinization threatens biodiversity, agriculture, and water [...] Read more.

This study investigates the salinization processes affecting the coastal aquifer within the Torre Guaceto State Nature Reserve, a Mediterranean coastal area characterized by a unique ecological value of a brackish wetland threatened by water-intensive agricultural activities. Groundwater salinization threatens biodiversity, agriculture, and water resource sustainability. This work integrates hydrogeological monitoring, geochemical and isotopic analyses, and geophysical surveys to understand salinity dynamics and identify key drivers, such as seawater intrusion, irrigation practices, and climate change. Data collected during monitoring campaigns from 2022 to 2024 reveal significant seasonal and spatial variations in groundwater salinity influenced by natural and human-induced factors. The results indicate that salt recycling from irrigation and marine spray deposition are important local contributors to groundwater salinity, in addition to seawater intrusion. These findings highlight the urgent need for integrated groundwater management approaches considering the combined effects of agricultural practices, irrigation water quality, and climate variability tailored to Mediterranean coastal ecosystems. Full article

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30 pages, 6809 KiB

Open AccessArticle

Laminaria digitata Supplementation as a Climate-Smart Strategy to Counteract the Interactive Effects of Marine Heatwaves and Disease Outbreaks in Farmed Gilthead Seabream (Sparus aurata)

by Isa Marmelo, Tomás Chainho, Daniel Bolotas, Alícia Pereira, Busenur Özkan, Cátia Marques, Iris A. L. Silva, Florbela Soares, Pedro Pousão-Ferreira, Elsa F. Vieira, Cristina Delerue-Matos, Zélia Silva, Paula A. Videira, Tiago Repolho, Mário Sousa Diniz, António Marques and Ana Luísa Maulvault

Environments 2025, 12(7), 226; https://doi.org/10.3390/environments12070226 - 30 Jun 2025

Abstract

Extreme weather events, such as marine heatwaves (MHWs), pose serious threats to the aquaculture sector, facilitating the occurrence of disease outbreaks and compromising farmed animals’ welfare and survival. Hence, finding eco-innovative strategies to improve animal immunocompetence is essential to assure aquaculture’s sustainability and [...] Read more.

Extreme weather events, such as marine heatwaves (MHWs), pose serious threats to the aquaculture sector, facilitating the occurrence of disease outbreaks and compromising farmed animals’ welfare and survival. Hence, finding eco-innovative strategies to improve animal immunocompetence is essential to assure aquaculture’s sustainability and resilience in a rapidly changing ocean. This study evaluated the immunostimulatory potential of Laminaria digitata powder (0.3% and 1.5%) and extract (0.3%) in juvenile gilthead seabream (Sparus aurata) exposed to a Vibrio harveyi outbreak during a Category III MHW event (T = 25.7 °C). Overall, L. digitata supplementation did not significantly affect fish immunocompetence under optimal rearing conditions (T = 21.4 °C; no infection), nor did it induce any adverse effects. However, both the powder (1.5%) and extract (0.3%) forms of L. digitata supplementation effectively mitigated the negative impacts prompted by the MHW and Vibrio harveyi infection—evidenced by improvements in fish health indicators, hematological parameters, leukocyte viability, granulocyte proportions, and reductions in peroxidase activity and immunoglobulin M levels. From an economic standpoint, supplementation with 1.5% L. digitata powder emerged as the most promising strategy, offering a practical balance between effectiveness and affordability for large-scale applications. These findings highlight the potential of L. digitata as an immunostimulatory aquafeed supplement, with promising benefits for fish health and resilience under adverse rearing conditions. Full article

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4 pages, 148 KiB

Open AccessEditorial

Special Issue “Advanced Research on Micropollutants in Water”

by Cátia A. L. Graça

Environments 2025, 12(7), 225; https://doi.org/10.3390/environments12070225 - 30 Jun 2025

Abstract

The increasing occurrence of micropollutants in aquatic environments has become a global concern due to their persistence, potential toxicity, and resistance to conventional water treatment processes [...] Full article

(This article belongs to the Special Issue Advanced Research on Micropollutants in Water)

21 pages, 3765 KiB

Open AccessArticle

Mineral Condition Changes in Amended Soils and Woody Vegetation Installed on a Polluted Soil with Trace Metals in Lubumbashi (DR Congo): Results of a Four-Year Trial

by Serge Langunu, Jacques Kilela Mwanasomwe, Dieu-donné N’Tambwe Nghonda, Gilles Colinet and Mylor Ngoy Shutcha

Environments 2025, 12(7), 224; https://doi.org/10.3390/environments12070224 - 30 Jun 2025

Abstract

The use of trees to revegetate urban areas contaminated by mining activity is a low-cost, low-maintenance technique, of which the success will depend on the plant species, planting methods, and geochemical processes at the soil-plant interface. This study analyzed the evolution of mineral [...] Read more.

The use of trees to revegetate urban areas contaminated by mining activity is a low-cost, low-maintenance technique, of which the success will depend on the plant species, planting methods, and geochemical processes at the soil-plant interface. This study analyzed the evolution of mineral composition in the rooting soil, tree, and herbaceous vegetation on soils contaminated by As, Cd, Cu, Co, Pb, and Zn. An in-situ experiment was carried out in Lubumbashi (South-eastern DR Congo) with six tree species (Acacia auriculiformis, Albizia lebbeck, Delonix regia, Leucaena leucocephala, Mangifera indica, and Syzygium guineense), in 0.187 m³ pits amended with municipal compost and limestone. After planting in the amended and unamended (control) pits, soil samples were taken for chemical analysis. Eighteen months after planting, a floristic inventory was carried out to assess the spontaneous colonization of herbaceous species. The results show an increase in metal concentrations in the rooting soil between 2019 and 2023 (Cu: 725 ± 136 to 6141 ± 1853 mg kg⁻¹; As: 16.2 ± 1.4 to 95 ± 28.5 mg kg⁻¹; Cd: 2.7 ± 1.3 to 8.7 ± 2.0 mg kg⁻¹; Co: 151 ± 36.3 to 182 ± 113 mg kg⁻¹; Zn: 558 ± 418 to 1098 ± 1037 mg kg⁻¹), with a stable pH and a decrease in nutrients (P, K, Ca, and Fe). The trees planted in the amended pits showed better height and diameter growth and greater survival than the controls, reaching average heights of 8 m and a DBH of up to 22 cm four years after planting. A total of 13 spontaneous herbaceous species were recorded, with an increased abundance during the second inventory. These results confirm the effectiveness of pit amendment for the rapid revegetation of urban soils polluted by trace metals. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Soil Contamination and Remediation)

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20 pages, 17149 KiB

Open AccessArticle

Assessment of Trail Erosion Under the Impact of Tourist Traffic in the Bucegi Mountains, Romanian Carpathians

by Mihai Radu Jula and Mircea Voiculescu

Environments 2025, 12(7), 223; https://doi.org/10.3390/environments12070223 - 28 Jun 2025

Abstract

Trail erosion is a global issue, particularly in mountainous regions, that is largely driven by increased tourist flows and uncontrolled trampling. Our study was conducted in the Bucegi Mountains, Southern Carpathians, Romania, along three of the most frequented hiking trails, each with varying [...] Read more.

Trail erosion is a global issue, particularly in mountainous regions, that is largely driven by increased tourist flows and uncontrolled trampling. Our study was conducted in the Bucegi Mountains, Southern Carpathians, Romania, along three of the most frequented hiking trails, each with varying levels of difficulty. Two of these trails cross both the forest and alpine zones, and the other crosses only the alpine zone: Jepii Mici, connecting the Bușteni resort (960 m a.s.l.) to Babele Chalet (2200 m a.s.l.); Jepii Mari, linking Bușteni resort to the National Sports Complex Piatra Arsă (1960 m a.s.l.); and the trail between Babele Chalet and Omu Peak (2505 m a.s.l.). Our analysis focused on morphometric parameters, the volume of displaced soil, and associated geohazards, serving as indicators for assessing the degradation state of hiking trails and their suitability for mountain biking and tourist traffic. The findings reveal a high degree of trail degradation, highlighted by increased trail width, the development of parallel trail sections due to dispersed tourist traffic, areas with abrupt gradient changes, and sections severely affected by erosion, resulting in significant volumes of displaced soil. These factors hinder effective tourist traffic, including hiking and mountain biking, and degrade the mountainous landscape. Conversely, the results can be useful for both monitoring annual trail erosion rates and facilitating tourist access, tailored to individual and group interests, as well as the physical readiness of each tourist, to offer a more pleasurable and sustainable experience. Full article

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15 pages, 1473 KiB

Open AccessArticle

Climate Change Impacts on Agricultural Suitability in Rio Grande do Sul, Brazil

by Emma Haggerty, Ethan R. Wertlieb and Dmitry A. Streletskiy

Environments 2025, 12(7), 222; https://doi.org/10.3390/environments12070222 - 28 Jun 2025

Abstract

Changing climatic conditions are significant determinants of agricultural productivity. Rio Grande do Sul is the southernmost state and the second-largest agricultural producer in Brazil. The suitability of its land for farming can be used as a proxy for agricultural and economic success, making [...] Read more.

Changing climatic conditions are significant determinants of agricultural productivity. Rio Grande do Sul is the southernmost state and the second-largest agricultural producer in Brazil. The suitability of its land for farming can be used as a proxy for agricultural and economic success, making it a pertinent case for exploring the consequences of climate change on major crop production. The latest available climate and environmental data was used to develop an agricultural Suitability Index (SI) that quantifies the suitability of land for rice, tobacco, soybean, and corn production in 2020 (present), 2050 (near-future), and 2100 (far-future) under moderate (SSP245) and extreme (SSP585) climate scenarios. SI scores for each municipality of Rio Grande do Sul consider inputs from a three-layer framework (climatic, non-climatic, and current production) to provide critical insight into potential shifts in agricultural productivity. While terrestrial suitability for crop growth varies both spatially and temporally, widespread decreases in suitability for all four crops are expected across the state under both scenarios. Soybean is expected to be the least affected crop, and rice is the most affected crop, tied to shifting patterns in precipitation, which significantly determines suitability. Local and state governments, agribusinesses, and family producers will have to adapt to environmental challenges to ensure the provision of food, labor, and economic security. Full article

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11 pages, 497 KiB

Open AccessOpinion

Beyond Biomass: Reimagining Microalgae as Living Environmental Nano-Factories

by Thinesh Selvaratnam, Shaseevarajan Sivanantharajah and Kirusha Sriram

Environments 2025, 12(7), 221; https://doi.org/10.3390/environments12070221 - 28 Jun 2025

Abstract

Microalgae have long been recognized for their potential in biofuel production and wastewater treatment, but their broader capabilities remain underexplored. This opinion paper presents a case for a significant shift in how microalgae are conceptualized from biomass producers to dynamic, multifunctional systems that [...] Read more.

Microalgae have long been recognized for their potential in biofuel production and wastewater treatment, but their broader capabilities remain underexplored. This opinion paper presents a case for a significant shift in how microalgae are conceptualized from biomass producers to dynamic, multifunctional systems that can serve as environmental nano-factories. It highlights emerging research on the role of microalgae in heavy metal sequestration, the green biosynthesis of metal nanoparticles, and the cascading valorization of residual biomass through environmentally sustainable extraction methods. Together, these applications offer a unified platform for pollution mitigation and the production of valuable materials. The paper also examines recent progress in synthetic biology, bioreactor design, and microbial consortia that could support this transition. At the same time, it acknowledges key challenges, including issues of scalability, regulatory acceptance, and process integration. Strategic recommendations are proposed to advance this field and align it more closely with circular economy models. By reimagining microalgae as living nano-factories, this paper outlines a path forward for developing integrated, sustainable technologies that simultaneously address environmental and industrial challenges. Full article

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24 pages, 8390 KiB

Open AccessArticle

Impact of Permanent Preservation Areas on Water Quality in a Semi-Arid Watershed

by Fernanda Helena Oliveira da Silva, Fernando Bezerra Lopes, Bruno Gabriel Monteiro da Costa Bezerra, Noely Silva Viana, Isabel Cristina da Silva Araújo, Nayara Rochelli de Sousa Luna, Michele Cunha Pontes, Raí Rebouças Cavalcante, Francisco Thiago de Alburquerque Aragão and Eunice Maia de Andrade

Environments 2025, 12(7), 220; https://doi.org/10.3390/environments12070220 - 27 Jun 2025

Abstract

Water is scarce in semi-arid regions due to environmental limitations; this situation is aggravated by changes in land use and land cover (LULC). In this respect, the basic ecological functions of Permanent Preservation Areas (PPAs) help to maintain water resources. The aim of [...] Read more.

Water is scarce in semi-arid regions due to environmental limitations; this situation is aggravated by changes in land use and land cover (LULC). In this respect, the basic ecological functions of Permanent Preservation Areas (PPAs) help to maintain water resources. The aim of this study was to evaluate the relationship between the LULC and water quality in PPAs in a semi-arid watershed, from 2009 to 2016. The following limnological data were analyzed: chlorophyll-a, transparency, total nitrogen and total phosphorus. The changes in LULC were obtained by classifying images from Landsat 5, 7 and 8 into three types: Open Dry Tropical Forest (ODTF), Dense Dry Tropical Forest (DDTF) and Exposed Soil (ES). Spearman correlation and principal component analysis were applied to evaluate the relationships between the parameters. There was a significant positive correlation between DDTF and the best limnological conditions. However, ES showed a significant negative relationship with transparency and a positive relationship with chlorophyll-a, indicating a greater input of sediments and nutrients into the water. The PCA corroborated the results of the correlation. It is therefore essential to prioritize the preservation and restoration of the vegetation in these sensitive areas to ensure the sustainability of water resources. Future studies should assess the impact of specific human activities, such as agriculture, deforestation and livestock farming, on water quality in the PPAs. Full article

(This article belongs to the Special Issue Rural Landscape Management and Conservation: Advances in GIS and Remote Sensing Applications)

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22 pages, 2211 KiB

Open AccessArticle

Seasonality of Pharmaceuticals and Personal Care Products in Shallow Lakes, Florida, USA—Part A

by Elzbieta Bialkowska-Jelinska, Philip van Beynen and Laurent Calcul

Environments 2025, 12(7), 219; https://doi.org/10.3390/environments12070219 - 27 Jun 2025

Abstract

Shallow lakes are highly vulnerable to pollution due to their small water volume. Those that receive effluent from the drainfields of onsite wastewater treatment systems (septic tanks) may contain pharmaceuticals and personal care products (PPCPs) that escaped removal during treatment. This study examined [...] Read more.

Shallow lakes are highly vulnerable to pollution due to their small water volume. Those that receive effluent from the drainfields of onsite wastewater treatment systems (septic tanks) may contain pharmaceuticals and personal care products (PPCPs) that escaped removal during treatment. This study examined the effects of seasonal rainfall variability on the assemblages and concentrations of fourteen PPCPs in two shallow lakes in West–Central Florida, USA: one surrounded by residents equipped with septic tanks and the other located within a nature preserve. Water samples were collected weekly during an 18-week interval from April to August 2021. Liquid chromatography–mass spectrometry analyses revealed the omnipresence of five PPCPs: theophylline, caffeine, cotinine, DEET, and testosterone, although acetaminophen, ibuprofen, and sulfamethoxazole were also common. Of all the PPCPs detected, theophylline, DEET, and acetaminophen concentrations were higher during the wet season in the septic tank-influenced lake, while caffeine, cotinine, and testosterone concentrations decreased. In the lake located in the nature preserve, theophylline, caffeine, and acetaminophen levels increased in the wet season. In contrast, cotinine, DEET, and testosterone levels decreased. Overall, more compounds were detected during the wet season, with highly hydrophobic PPCPs (fluoxetine, atorvastatin, and octocrylene) only present during this period. Full article

(This article belongs to the Special Issue Research Progress in Groundwater Contamination and Treatment)

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17 pages, 1618 KiB

Open AccessArticle

A Phosphorus Microfractionation (P-MF) Method for Measuring Phosphorus Fractions in Small Quantities of Suspended Solids and Sediments: Detailed Method and Example Application

by Jacob B. Taggart, Rebecca L. Ryan, A. Woodruff Miller, Theron G. Miller and Gustavious P. Williams

Environments 2025, 12(7), 218; https://doi.org/10.3390/environments12070218 - 26 Jun 2025

Abstract

The standard methods for sediment phosphorus (P) fractionation are impractical for use with suspended solids due to the inherent difficulties associated with collecting sufficient sample quantities for analysis. To allow the fractionation analysis of small quantities of suspended solids or sediment, we developed [...] Read more.

The standard methods for sediment phosphorus (P) fractionation are impractical for use with suspended solids due to the inherent difficulties associated with collecting sufficient sample quantities for analysis. To allow the fractionation analysis of small quantities of suspended solids or sediment, we developed a P-microfractionation (P-MF) method and evaluated the minimum sample size threshold. The dry mass threshold is likely <1.0 g for Utah Lake suspended solids and between 0.35 and 0.99 g for Utah Lake sediments, though we recommend experimentation to refine these thresholds for other locations, as Utah Lake sediment P concentrations are high (~1000 mg kg⁻¹). We estimated dry mass using duplicate samples, as drying a sample changes the P fractions. We show that Utah Lake suspended solids have a significantly higher P content across most P fractions compared to those in sediments, emphasizing the importance of considering suspended solids when managing water nutrient levels in eutrophic water bodies. P-MF has the potential to enable researchers to use reasonably sized water samples to assess the P sorption behavior of suspended solids, a measurement not typically performed. Full article

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21 pages, 3040 KiB

Open AccessArticle

Drinking Water and Sanitation Safety Planning for Medical Facilities: An Innovative PoU Approach for a Water System Description Using Ecomaps

by Lara Kamm, Ralf M. Hagen, Nico T. Mutters, Ricarda M. Schmithausen, Ruth Weppler and Manuel Döhla

Environments 2025, 12(7), 217; https://doi.org/10.3390/environments12070217 - 26 Jun 2025

Abstract

Drinking Water Safety Plans (DWSP) in buildings serve to identify health hazards associated with the drinking water system. Sanitation Safety Plans (SSP) fulfill the same purpose for the sewage system. Water Safety Plans (WSP) include DWSPs, SSPs, and water systems like gray water [...] Read more.

Drinking Water Safety Plans (DWSP) in buildings serve to identify health hazards associated with the drinking water system. Sanitation Safety Plans (SSP) fulfill the same purpose for the sewage system. Water Safety Plans (WSP) include DWSPs, SSPs, and water systems like gray water and firefighting water. WSPs are based on a high-quality description of the water systems. This paper presents a new methodology for describing water systems. In contrast to previous approaches, the system description begins at the point where the water is consumed. These points of use are described using ecomaps, which are then supplemented with information about the pipe network. This approach makes it possible to fulfill four relevant premises: (1) the system description includes all essential parts of the drinking water installation, (2) the system description is possible with usual equipment, (3) the system description can be carried out with the least possible additional personnel costs, and (4) the system description is controllable, versionable, changeable, and forgery-proof. The ecomaps created in this way are suitable for the next step within the WSP framework, namely hazard and risk assessment. In addition, the ecomaps can be integrated into a quality, occupational safety, or environmental management system. Aspects of water security can be added to enable the ecomaps to be used as the basis for a total integrated water management system. Full article

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24 pages, 2993 KiB

Open AccessArticle

Multi-Output Machine-Learning Prediction of Volatile Organic Compounds (VOCs): Learning from Co-Emitted VOCs

by Abdelrahman Eid, Shehdeh Jodeh, Ghadir Hanbali, Mohammad Hawawreh, Abdelkhaleq Chakir and Estelle Roth

Environments 2025, 12(7), 216; https://doi.org/10.3390/environments12070216 - 26 Jun 2025

Abstract

Volatile Organic Compounds (VOCs) are important contributors to indoor and occupational air pollution, such as environments involving the extensive use of paints and solvents. The routine measurement of VOCs is often limited by resource constraints, creating a need for indirect estimation techniques. This [...] Read more.

Volatile Organic Compounds (VOCs) are important contributors to indoor and occupational air pollution, such as environments involving the extensive use of paints and solvents. The routine measurement of VOCs is often limited by resource constraints, creating a need for indirect estimation techniques. This work presents the need for a predictive framework that offers a practical, interpretable alternative to a full-spectrum chemical analysis and supports early exposure detection in resource-limited settings, contributing to environmental health monitoring and occupational risk assessment. This study explores the capability of machine learning to simultaneously predict the concentrations of five paint-related VOCs using other co-emitted VOCs along with demographic variables. Three models—Multi-Output Gaussian Process Regression (MOGP), CatBoost Multi-Output Regressor, and Multi-Output Neural Networks—were calibrated and each achieved a high predictive performance. Further, a feature importance analysis is conducted and showed that certain VOCs and some demographic variables consistently influenced the predictions across all models, pointing to common exposure determinants for individuals, regardless of their specific exposure setting. Additionally, a subgroup analysis identified the exposure disparities across demographic groups, supporting targeted risk mitigation efforts. Full article

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29 pages, 28225 KiB

Open AccessReview

Toxic Legacy—Environmental Impacts of Historic Metal Mining and Metallurgy in the Harz Region (Germany) at Local, Regional and Supra-Regional Levels

by Louisa Friederike Steingräber, Friedhart Knolle, Horst Kierdorf, Catharina Ludolphy and Uwe Kierdorf

Environments 2025, 12(7), 215; https://doi.org/10.3390/environments12070215 - 26 Jun 2025

Abstract

As a legacy of historical metal mining and the processing and smelting of metalliferous ores, metal pollution is a serious environmental problem in many areas around the globe. This review summarizes the history, technical development and environmental hazards of historic metal mining and [...] Read more.

As a legacy of historical metal mining and the processing and smelting of metalliferous ores, metal pollution is a serious environmental problem in many areas around the globe. This review summarizes the history, technical development and environmental hazards of historic metal mining and metallurgical activities in the Harz Region (Germany), one of the oldest and most productive mining landscapes in Central Europe. The release of large amounts of metal-containing waste into rivers during historic ore processing and the ongoing leaching of metals from slag heaps, tailings dumps and contaminated soils and sediments are the main sources of metal pollution in the Harz Mountains and its foreland. This pollution extends along river systems with tributaries from the Harz Mountains and can even be detected in mudflats of the North Sea. In addition to fluvial discharges, atmospheric pollution by smelter smoke has led to long-term damage to soils and vegetation in the Harz Region. Currently, the ecological hazards caused by the legacy pollution from historical metal mining and metallurgy in the Harz Region are only partially known, particularly regarding the effects of changes in river ecosystems as a consequence of climate change. This review discusses the complexity and dynamics of human–environment interactions in the Harz Mountains and its surroundings, with a focus on lead (Pb) pollution. The paper also identifies future research directions with respect to metal contamination. Full article

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27 pages, 2490 KiB

Open AccessArticle

Lavender as a Bioindicator: Bioaccumulation Assessment of Cd, Pb, and Zn

by Daniela Simina Ștefan, Ecaterina Anca Șerban, Magdalena Boșomoiu, Camelia Ungureanu and Mircea Ștefan

Environments 2025, 12(7), 214; https://doi.org/10.3390/environments12070214 - 25 Jun 2025

Abstract

This study explores the bioaccumulation behavior of heavy metals (cadmium (Cd), lead (Pb), and zinc (Zn)) in lavender (Lavandula spp.) cultivated under controlled greenhouse conditions to assess its potential in sustainable phytoremediation. The plants were grown in pots filled with either unpolluted [...] Read more.

This study explores the bioaccumulation behavior of heavy metals (cadmium (Cd), lead (Pb), and zinc (Zn)) in lavender (Lavandula spp.) cultivated under controlled greenhouse conditions to assess its potential in sustainable phytoremediation. The plants were grown in pots filled with either unpolluted soil or soil artificially enriched with cadmium, lead, or zinc at concentrations exceeding the normal (Cd 1 mg/kg d.w.; Pb 20 mg/kg d.w.; Zn 100 mg/kg d.w.), alert (Cd 3 mg/kg d.w.; Pb 50 mg/kg d.w.; Zn 300 mg/kg d.w.), and intervention (Cd 5 mg/kg d.w.; Pb 100 mg/kg d.w.; Zn 600 mg/kg d.w.) thresholds set for sensitive land use. A comparative analysis of two lavender varieties (lavender and lavandin) over a four-month period revealed an accumulation trend of Pb > Cd > Zn. Empirical modeling indicated that cadmium uptake followed a linear pattern, lead accumulation conformed closely to the Mitscherlich model, while zinc uptake did not align well with any of the tested models. Overall, the results emphasize the potential of lavender species in developing biomimetic approaches for heavy metal remediation and contribute valuable insights into sustainable soil decontamination practices. Full article

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14 pages, 1353 KiB

Open AccessArticle

Effect of Multi-Walled Carbon Nanotubes in the Snail Cornu aspersum

by Davide Gualandris, Francesco Dondero, Alberico Franzin, Davide Rotondo, Candida Lorusso, Teodoro Semeraro and Antonio Calisi

Environments 2025, 12(7), 213; https://doi.org/10.3390/environments12070213 - 24 Jun 2025

Abstract

The progressive commercial deployment of multi-walled carbon nanotubes (MWCNTs) raises concerns about their terrestrial ecotoxicity. We exposed adult Cornu aspersum (150 snails; five replicates of three animals per time-point) to 50 mg L⁻¹ MWCNT-dosed Lactuca sativa for 30 days and quantified five [...] Read more.

The progressive commercial deployment of multi-walled carbon nanotubes (MWCNTs) raises concerns about their terrestrial ecotoxicity. We exposed adult Cornu aspersum (150 snails; five replicates of three animals per time-point) to 50 mg L⁻¹ MWCNT-dosed Lactuca sativa for 30 days and quantified five mechanistic biomarkers alongside survival. Hemocyte spread-cell area increased by 48% (from 243 ± 22 µm² at day 0 to 360 ± 18 µm² at day 14, p < 0.001). Lysosomal membrane stability (neutral red retention) fell twofold within 72 h and to 10 min by day 30 (controls ≈ 60 min), indicating early, persistent destabilization. Micronucleus frequency rose above the ecogenotoxic threshold of 5‰ after 7 days, peaking at 8.3 ± 0.7‰ on day 14 (p < 0.01). Hepatopancreas metallothionein concentrations doubled by day 3 (2.1 ± 0.3 vs. 1.0 ± 0.2 µg g⁻¹ ww in controls) and remained >150% of control throughout exposure, consistent with metal impurity mobilization. Acetylcholinesterase activity in cephalic tissue declined by 50% after 7 days and by 73% after 30 days, revealing sustained neurotoxicity. Despite these pronounced sub-individual disturbances, cumulative mortality reached only 19% at day 30, suggesting substantial, but finite, physiological compensation. Collectively, the data demonstrate that a 50 mg L⁻¹ dietary load of MWCNTs elicits rapid cytotoxic, genotoxic, and neurotoxic responses in C. aspersum that precede overt lethality, underscoring the utility of this gastropod and the chosen biomarker suite for monitoring nanotube contamination in agro-ecosystems and food-grade snail farming. Full article

(This article belongs to the Special Issue Environmental Pollution Risk Assessment)

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22 pages, 1199 KiB

Open AccessArticle

Assessment of Health Risks Associated with PM₁₀ and PM_2.5 Air Pollution in the City of Zvolen and Comparison with Selected Cities in the Slovak Republic

by Patrick Ivan, Marián Schwarz and Miriama Mikušová

Environments 2025, 12(7), 212; https://doi.org/10.3390/environments12070212 - 20 Jun 2025

Abstract

Air pollution is one of the most serious environmental threats, with particulate matter PM₁₀ and PM_2.5 representing its most harmful components, significantly affecting public health. These particles are primarily generated by transport, industry, residential heating, and agriculture, and are associated with [...] Read more.

Air pollution is one of the most serious environmental threats, with particulate matter PM₁₀ and PM_2.5 representing its most harmful components, significantly affecting public health. These particles are primarily generated by transport, industry, residential heating, and agriculture, and are associated with increased incidence of respiratory and cardiovascular diseases, asthma attacks, and heart attacks, as well as chronic illnesses and premature mortality. The most vulnerable groups include children, the elderly, and individuals with pre-existing health conditions. This study focuses on the analysis of health risks associated with PM₁₀ and PM_2.5 air pollution in the city of Zvolen, which serves as a representative case due to its urban structure, traffic load, and industrial activity. The aim is to assess the current state of air quality, identify the main sources of pollution, and evaluate the health impacts of particulate matter on the local population. The results will be compared with selected Slovak cities—Banská Bystrica and Ružomberok—to understand regional differences in exposure and its health consequences. The results revealed consistently elevated concentrations of particulate matter (PM) across all analyzed cities, frequently exceeding the guideline values recommended by the World Health Organization (WHO), although remaining below the thresholds set by current national legislation. The lowest average concentrations were recorded in the city of Zvolen (PM₁₀: 20 μg/m³; PM_2.5: 15 μg/m³). These lower values may be attributed to the location of the reference monitoring station operated by the Slovak Hydrometeorological Institute (SHMÚ), situated on J. Alexy Street in the southern part of the city—south of Zvolen’s primary industrial emitter, Kronospan. Due to predominantly southerly wind patterns, PM particles are transported northward, potentially leading to higher pollution loads in the northern areas of the city, which are currently not being monitored. We analyzed trends in PM₁₀ and PM_2.5 concentrations and their relationship with hospitalization data for respiratory diseases. The results indicate a clear correlation between the concentration of suspended particulate matter and the number of hospital admissions due to respiratory illnesses. Our findings thus confirm the significant adverse effects of particulate air pollution on population health and highlight the urgent need for systematic monitoring and effective measures to reduce emissions, particularly in urban areas. Full article

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20 pages, 1973 KiB

Open AccessArticle

Greenhouse Gas Emissions from Fertilization Practices in Maize Cropping in Sub-Saharan Africa: Toward Climate-Smart Agriculture

by Pawend-taoré Christian Bougma, Loyapin Bondé, Valaire Séraphin Ouehoudja Yaro, Idrissa Dicko, Aurelie Flavy Rufine Zongo, Amanuel Woldeselassie Gebremichael, Mounkaila Mohamed, Claudia Malz, Jörg Matschullat, Anja Linstädter and Oumarou Ouédraogo

Environments 2025, 12(7), 211; https://doi.org/10.3390/environments12070211 - 20 Jun 2025

Abstract

The intensive use of nitrogen (N) fertilizers in maize (Zea mays L.) cropping in sub-Saharan Africa (SSA) contributes significantly to nitrous oxide (N₂O) emissions. Due to limited data on emissions and emission factors (EFs) in SSA, this study investigates GHG [...] Read more.

The intensive use of nitrogen (N) fertilizers in maize (Zea mays L.) cropping in sub-Saharan Africa (SSA) contributes significantly to nitrous oxide (N₂O) emissions. Due to limited data on emissions and emission factors (EFs) in SSA, this study investigates GHG emissions and proposes EFs under different fertilization regimes in maize cropping in Burkina Faso (West Africa). A randomized complete block design was used with five treatments: (i) control: no fertilizer (CK), (ii) cattle manure (M), (iii) chemical fertilizer (NPK), (iv) a combination of chemical fertilizer and cattle manure (NPKM) at the national recommended rate, and (v) farmers’ practices, which involve chemical fertilizer combined with manure at the farmers’ rate (NPKM+). Cumulative N₂O emissions varied significantly among treatments (p < 0.05), with the highest under NPKM (2.86 kg N₂O-N ha⁻¹) and the lowest under CK (1.93 ± 0.11 kg N₂O-N ha⁻¹). NPKM also showed the highest methane (CH₄) uptake (−0.62 kg CH₄-C ha⁻¹; p < 0.001), while CK exhibited an increasing trend (0.74 kg CH₄-C ha⁻¹). The highest N₂O EF was recorded for NPK (0.37 ± 0.05%), 63% lower than the Intergovernmental Panel on Climate Change default value. Although NPKM treatment resulted in the highest global warming potential and maize yield, it also achieved the lowest greenhouse gas intensity per unit of yield, highlighting a more efficient trade-off between productivity and climate impact with nitrogen fertilizer use. NPKM+ was the most effective in maintaining high maize productivity with lower yield-scaled N₂O emissions and GHG intensity. These findings suggest that an integrated approach combining organic and inorganic fertilizers can mitigate soil GHG emissions. Further research is needed to refine climate-smart fertilizer combinations for sustainable maize production in SSA. Full article

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17 pages, 2373 KiB

Open AccessArticle

Analytical Workflow for Tracking Aquatic Biomass Responses to Sea Surface Temperature Changes

by Teodoro Semeraro, Jessica Titocci, Lorenzo Liberatore, Flavio Monti, Francesco De Leo, Gianmarco Ingrosso, Milad Shokri and Alberto Basset

Environments 2025, 12(7), 210; https://doi.org/10.3390/environments12070210 - 20 Jun 2025

Abstract

Ocean ecosystem services provisioning is driven by phytoplankton, which form the base of the ocean food chain in aquatic ecosystems and play a critical role as the Earth‘s carbon sink. Phytoplankton is highly sensitive to temperature, making it vulnerable to the effects of [...] Read more.

Ocean ecosystem services provisioning is driven by phytoplankton, which form the base of the ocean food chain in aquatic ecosystems and play a critical role as the Earth‘s carbon sink. Phytoplankton is highly sensitive to temperature, making it vulnerable to the effects of temperature variations. The aim of this research was to develop and test a workflow analysis to monitor the impact of sea surface temperature (SST) on phytoplankton biomass and primary production by combining field and remote sensing data of Chl-a and net primary production (NPP) (as proxies of phytoplankton biomass). The tropical zone was used as a case study to test the procedure. Firstly, machine learning algorithms were applied to the field data of SST, Chl-a and NPP, showing that the Random Forest was the most effective in capturing the dataset’s patterns. Secondly, the Random Forest algorithm was applied to MODIS SST images to build Chl-a and NPP time series. The time series analysis showed a significant increase in SST which corresponded to a significant negative trend in Chl-a concentrations and NPP variation. The recurrence plot of the time series revealed significant disruptions in Chl-a and NPP evolutions, potentially linked to El Niño–Southern Oscillation (ENSO) events. Therefore, the analysis can help to highlight the effects of temperature variation on Chl-a and NPP, such as the long-term evolution of the trend and short perturbation events. The methodology, starting from local studies, can support broader spatial–temporal-scale studies and provide insights into future scenarios. Full article

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