High Contamination Research Articles

Microbiological characterization of drinking water and socio-environmental study in the peri-urban area of La Plata, Buenos Aires, Argentina

ABSTRACT The aim was to analyze the groundwater quality and evaluate the socio-environmental factors associated with the indicators of environmental contamination in the peri-urban area of La Plata. A descriptive cross-sectional study was conducted between 2013 and 2023, and six neighborhoods were selected. Water samples were taken according to the Argentine Food Code and a parasitological analysis of the water was performed using ultrafiltration. Socio-environmental analyses were carried out with semi-structured questionnaires and a generalized linear model was used considering a binomial distribution. Of the total water samples, 70% (75/106) indicated that the water is not suitable for consumption. The highest contamination by total coliforms was observed in Abasto, and the risk of contamination by this indicator was higher (odds ratio > 5) compared to other neighborhoods. A moderate percentage of fecal coliforms and Escherichia coli was found in Melchor Romero and El Peligro, although it was higher than that detected in the other neighborhoods. Pseudomonas spp. was observed in all the samples in Arana and in moderate amounts in Abasto and Lisandro Olmos. Entamoeba spp. and Blastocystis spp. were found in a quarter of the water samples. It is essential to manage environmental sanitation and family health access policies.

Comprehensive tetracycline, ciprofloxacin and sulfamethoxazole toxicity evaluation to earthworm Dendrobaena veneta through life-cycle, behavioral and biochemical parameters.

Veterinary antibiotics are widely spread in the environment, however, the knowledge about their impact on soil key species is still limited. This study evaluated the short-term and long-term effects of tetracycline (TC), ciprofloxacin (CIP) and sulfamethoxazole (SMX) (1-500 mg kg) on earthworm Dendrobaena veneta by measuring multiple parameters (survival, growth, reproduction, behavior and biochemical responses). Neither antibiotic induced acute toxicity and low mortality was observed after chronic exposure. TC and CIP had a negligible effect on the earthworm's weight from the 6th week of exposure, SMX inhibited the earthworm growth when was present in the range of 50-500 mg kg-1. In parallel, SMX reduced earthworm reproduction at environmentally relevant concentrations. Antibiotics altered superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and gluthathione-S-transferase (GST) activities and induced lipid peroxidation. Overall, earthworms showed no apparent acute response at environmentally relevant concentrations except for avoidance behavior; after long-term exposure earthworms experienced biochemical, physiological, and reproductive impairments and reduced survival at high soil contamination.

Enhancing source identification of water-soluble heavy metal contamination in urban road sediments: a receptor model approach for water and sediment quality in a Chinese metropolitan area

Abstract This study investigates the concentrations and sources of 8 heavy metals in urban road sediments and a total of 116 samples were collected from 29 locations, with four samples per location from Zhengzhou, China. Pb concentrations significantly exceeded background values, while Hg levels showed variability across locations. Pollution indices reveal that Cu and Cd, two hazardous metals, contribute significantly to urban road dust pollution. Notably, Hg shows high contamination levels, while Pb and Cr exhibit moderate contamination. The measured concentrations of the heavy metals are: Cr (28.32 μg l–1), Cu (334.65 μg l–1), Cd (2.87 μg l–1), Ni (83.20 μg l–1), Zn (204.10 μg l–1), As (45.10 μg l–1), Pb (4.11 μg l–1), and Hg (0.27 μg l–1). Using principal component analysis (PCA), three primary components (PC1, PC2, and PC3) were identified, explaining 86.85% of the variance in heavy metal concentrations. PC1, dominated by Cr and Pb, suggests industrial activities as the main source. PC2, influenced by As and Cd, reflects pollution from agrochemical use, while PC3, with high Ni values, indicates sources from alloy production and electroplating processes. These findings highlight the urgent need for targeted environmental management strategies to mitigate the health and ecological risks posed by heavy metal contamination in urban environments.

Temporal Variations, Air Quality, Heavy Metal Concentrations, and Environmental and Health Impacts of Atmospheric PM2.5 and PM10 in Riyadh City, Saudi Arabia

Atmospheric particulate matter (PM) samples were collected in Riyadh, Saudi Arabia, to assess air quality, quantify, heavy metal concentrations, and evaluate related ecological and health risks. This study’s uniqueness stems from its focused and detailed analysis of PM pollution in Riyadh, including an extensive assessment of heavy metal concentrations across different PM sizes by applying diverse pollution and health indices. This brings to light critical health and ecological issues and provides foundation for targeted pollution control efforts in the region. The study focused on two PM size fractions, PM2.5 and PM10 and analyzed the presence of heavy metals, including iron (Fe), nickel (Ni), chromium (Cr), zinc (Zn), cobalt (Co), copper (Cu), silver (Ag), arsenic (As), cadmium (Cd), and lead (Pb), using inductively coupled plasma emission spectrometry. Results showed significantly higher levels of PM10 (223.12 ± 66.12 µg/m3) compared to PM2.5 (35.49 ± 9.63 µg/m3), suggesting that local dust is likely a primary source. Air quality varied from moderate to unhealthy, with PM10 posing substantial risks. Heavy metal concentrations in PM2.5 followed the order Fe (13.14 ± 11.66 ng/m3) > As (2.87 ± 2.08 ng/m3) > Cu (0.71 ± 0.51 ng/m3) > Zn (0.66 ± 0.46 ng/m3) > Cr 0.50 ± 0.23 ng/m3) > Pb (0.14 ± 0.10 ng/m3) > Ni (0.03 ± 0.04 ng/m3) > Cd (0.004 ± 0.002 ng/m3) > Ag (0.003 ± 0.003 ng/m3) > Co (0.002 ± 0.004 ng/m3). In PM10, they followed the order Fe (743.18 ± 593.91 ng/m3) > As (20.12 ± 13.03 ng/m3) > Cu (10.97 ± 4.66 ng/m3) > Zn (9.06 ± 5.50 ng/m3) > Cr (37.5 ± 2.70 ng/m3) > Ni (1.72 ± 01.54 ng/m3) > Pb (1.11 ± 0.64 ng/m3) > Co (0.25 ± 0.28 ng/m3) > Ag (0.10 ± 0.26 ng/m3) > Cd (0.04 ± 0.02 ng/m3). Enrichment factor analysis revealed elevated levels for the metals Cu, Zn, As, Ag, Cd, and Pb. Pollution indices indicated various contamination levels, with Ag and As showing particularly high contamination and ecological risks. The study highlighted significant health concerns, especially from As, which poses a substantial long-term carcinogenic threat. The findings emphasize the urgent need to reduce hazardous metal levels in Riyadh’s air, especially with high child exposure.

Particle induced x-ray emission (pixe) assisted technique in the evaluation of potential ecological risks of heavy metals in surface sediments of Oba-Ile River, Ifelodun Local Government Area, Osun-State, Nigeria

The seasonal evaluation of trace elements in the surface sediments collected from Oba-Ile River, using Particle Induced X-Ray Emission (PIXE) Spectroscopy had been carried out. This was done so as to provide information about the pollution status of the river during the rainy and dry seasons. The samples were subjected to trace metal profiling using a 2.5 Mev proton available at the Ion Beam Analysis (IBA)/accelerator laboratory, Centre for Energy Research and Development (CERD), Obafemi Awolowo University, Ile-Ife. The facility is centered on a NEC 5SDH 1.7 MV Pelletron accelerator, equipped to provide proton and helium ions. A multi-elemental estuarine sediments referenced material (SRM 1646a purchased from NIST) was used for the determination of H-value which was subsequently used for analyzing the samples and assured the accuracy of the experimental procedure. The order of abundance of the 16 elements identified was Si > Fe >Al >K > Ca >Ti > Na > Mg > Zr > Mn > Sr > V > Cr > Zn > Pb > Cu. The contamination factor indicated that the metals presented a low contamination factor (LCf) to moderate contamination factor (MCf) except for Fe and Zr which presented a considerable contamination (CCf) and a very high contamination factor (VHCf) respectively. Other contamination indices indicated that Fe had either a moderate enrichment (ME) factor or a significant enrichment (SE) factor, thereby suggesting that Oba-Ile River sediment was particularly enriched in Fe

Effect of Iron Contamination and Polysilicon Gettering on the Performance of Polysilicon‐Based Passivating Contact Solar Cells

ABSTRACTOver the past decade, silicon solar cells with carrier‐selective passivating contacts based on polysilicon capping an ultra‐thin silicon oxide (commonly known as TOPCon or POLO) have demonstrated promising efficiency potentials and are regarded as an evolutionary upgrade to the PERC (passivated emitter and rear contact) cells in manufacturing. The polysilicon‐based passivating contacts also exhibit excellent gettering effects that relax the wafer and cleanroom requirements to some extent. In this work, we experimentally explore the impact of bulk iron contamination and polysilicon gettering on the passivation quality of the polysilicon/oxide structure and the resulting solar cells performance. Results show that both n‐ and p‐type polysilicon/oxide passivating contacts are not affected by iron gettering, demonstrating robust and stable passivation quality. However, for a very high bulk iron contamination (1 × 1013 cm−3), the accumulated iron in the p‐type lightly boron‐doped emitter in crystalline silicon would degrade the emitter saturation current density. This can cause a reduction in both open‐circuit voltage and short‐circuit current. Meanwhile, this very high iron content (1 × 1013 cm−3) can further degrade the fill factor and temperature coefficient of the cells. On the other hand, for an initial iron content of 2 × 1012 cm−3, which should be well above the iron level in the current industrial Czochralski silicon wafers, the resulting cells demonstrate similar performance as the control group with no intentional iron contamination. This work brings attention to both the benefits of polysilicon gettering effects as well as the potential degradation due to the accumulation of metal impurities in the p‐type emitter region.

Water quality classification using self-organizing maps and cluster analysis: Case of Meknes-El Hajeb Springs, Morocco.

The Ouislane sub-watershed is currently experiencing severe water shortages and is highly dependent on its water supply. The sub-watershed spans two communes: Meknes to the north and El Hajeb to the south. It serves as the primary water source for irrigation and drinking purposes for the local population. Consequently, it is crucial to assess the spatio-temporal variations of water quality to identify and address potential gaps; these focused on effective monitoring systems to detect contaminants, pollutants and health risks. This research project aims on the application of self-organizing map (SOM) techniques combined with cluster analysis to classify water quality in springs for drinking and irrigation purposes. The present study evaluates the water quality variations using physicochemical parameters of twelve water springs, collected during the wet and dry seasons of 2022. For this purpose, the water quality index (WQI), self-organizing map (SOM), hierarchical cluster analysis (HCA), and principal component analysis (PCA) are used as evaluation and classification methods. As a result, the SOM algorithm with a size of 5 × 5 units identified as the most suitable, based on the minimum quantization error (QE) and topographic error (TE), yielding a QE of 0.379 and a TE of 0.000. It grouped the water quality data into five distinct clusters, Cluster I represented 37.5% of the total samples, while cluster II represented 25%. Cluster III and IV each accounted for 8.33% of the samples, while 20.83% of the sampling water are classified in cluster V. Clusters I, II, and IV indicate good water suitable for drinking. However, cluster V had the highest WQI, suggesting very high contamination due to increased levels of the 10 studied physicochemical parameters. The water quality in this region (cluster V) is influenced by natural processes, such as precipitation intensity, weathering and vegetation cover, as well as anthropogenic factors like agriculture and urban concentration. PCA confirmed the clustering results obtained by SOM. However, SOM provides a more detailed classification and additional insights into the dominant variables influencing the classification processes. The results of this study suggest that SOM was an effective tool for gaining a better understanding of the patterns and processes driving water quality in the Ouislane sub-watershed and provides valuable avenues for further research to establish and monitor water quality for effective management of water resources.

Accumulation of Acyl Plastoquinol and Triacylglycerol in Six Cyanobacterial Species with Different Sets of Genes Encoding Type-2 Diacylglycerol Acyltransferase-like Proteins.

Recently, acyl plastoquinol (APQ) and plastoquinone-B (PQ-B), which are fatty acid esters of plastoquinol and plastoquinone-C respectively, have been identified as the major neutral lipids in cyanobacteria. In Synechocystis sp. PCC 6803, Slr2103 having homology with the eukaryotic enzyme for triacylglycerol (TAG) synthesis, diacylglycerol acyltransferase 2 (DGAT2), was identified as responsible for the synthesis of these plastoquinone-related lipids. On the other hand, TAG synthesis in cyanobacteria remains controversial due to the low accumulation level within cyanobacterial cells together with the high contamination level from the environment. In this study, to quantify more precisely and elucidate the relationship between the accumulation of neutral lipids and the presence or absence of DGAT2-like genes, plastoquinone-related lipids and TAG were analyzed directly from total lipids of six cyanobacterial species with different sets of genes encoding DGAT2-like proteins belonging to two distinct subclades. The results showed that the synthesis of these neutral lipids is highly dependent on clade A DGAT2-like proteins under the culture conditions used in this study, although accumulation level of TAG was quite low. In contrast to APQ highly abundant in saturated fatty acids, the fatty acid composition of TAG was species-specific and partly reflected the total lipid composition. Gloeobacter violaceus PCC 7421, which lacks a DGAT2-like gene, accumulated APQ with a high proportion of C18:0, suggesting APQ synthesis by an unidentified acyltransferase.

Manganese pollution in eastern India causing cancer risk.

Groundwater poisoning by heavy metals has caused serious health hazards in the exposed population globally. Manganese (Mn) poisoning causing human health hazards is very meagerly reported worldwide. The present research elucidates for the first time the catastrophic effect of manganese causing cancer in the Gangetic plains of Bihar (India). The blood samples of n = 1146 cancer patients were voluntarily obtained for the study, after their consent. Their household water samples were also collected for the study. All the samples were analysed for Mn contamination by Atomic Absorption Spectrophotometer. The study indicates high Mn contamination in the cancer patient blood samples with highest content as 6022µg/L. Moreover, the cancer patient's household handpump water samples also contained elevated Mn contamination. The correlation coefficient study finds significant association between Mn contamination in blood of cancer patients and their handpump water. The carcinoma group of cancer patients mostly in Stage III & IV had significant Mn contamination in their blood (above WHO/BIS permissible limit). The geospatial study depicts Mn contamination in handpump water in the state of Bihar in correlation with cancer patient's blood samples. This novel finding is being reported in India for the first time, which correlates cancer with handpump drinking water. The long-term Mn exposure could be one of the causative agents for elevating cancer incidences. However, other confounding risk factors cannot be denied.

Molecular and Serological Findings in Sheep During Two Coxiella burnetii Outbreaks in Sicily (Southern Italy).

Q fever is a widespread zoonotic disease caused by the obligate intracellular bacterium Coxiella burnetii, primarily transmitted through the inhalation of contaminated aerosols. This study aimed to detect C. burnetii in two Sicilian sheep flocks, with no better defined reproductive disorders reported by the farmers. Blood, individual and bulk milk, ticks, and conjunctival swabs were collected from both flocks (A and B). Real-time and traditional PCRs were carried out to detect C. burnetii DNA and anti-C. burnetii antibodies were searched using an ELISA. In terms of Farm A, C. burnetii DNA was detected in 7.1% of blood samples, 20% of individual milk samples, bulk milk, 66.6% of conjunctival swabs, and in all the examined tick pools. Anti-C. burnetii antibodies were found in 77.0% of sera, 92.5% of individual milk samples, and bulk milk. In terms of Farm B, C. burnetii DNA was detected in 3.8% of blood samples, 39.4% of individual milk samples, bulk milk, 100% of conjunctival swabs, and in all tick pools; anti-C. burnetii antibodies were present in 53.6% of sera, 73.2% of milk samples, and in bulk milk. Our results highlight the high diffusion of C. burnetii in the two outbreaks, with widespread pathogen circulation, significant shedding in dairy products, and high environmental contamination, highlighting the need for enhanced surveillance and control measures in dairy sheep farms.

Chlorella vulgaris as a food substitute: Applications and benefits in the food industry.

Chlorella vulgaris, a freshwater microalga, is gaining attention for its potential as a nutritious food source and dietary supplement. This review aims to provide a comprehensive discussion on C. vulgaris, evaluating its viability as a food substitute in the industry by exploring the nutritional value and application of C. vulgaris in the food industry. Rich in protein, lipids, carbohydrates, vitamins, and minerals, Chlorella offers substantial nutritional benefits, positioning it as a valuable food substitute. Its applications in the food industry include incorporation into smoothies, snacks, and supplements, enhancing the nutritional profile of various food products. The health benefits of Chlorella encompass antioxidant activity, immune system support, and detoxification, contributing to overall well-being. Despite these advantages, the commercialization of Chlorella faces significant challenges. These include variability in antibacterial activity due to strain and growth conditions, high production costs, contamination risks, and sensory issues such as unpleasant taste and smell. Additionally, Chlorella can accumulate heavy metals from its environment, necessitating stringent quality control measures. Future prospects involve improving Chlorella strains through genetic manipulation to enhance nutrient content, developing cost-effective culture systems, and exploring advanced processing techniques like pulsed electric fields for better digestibility. Addressing sensory issues through flavor-masking strategies and employing environmental management practices will further support Chlorella's integration into the food industry. Although C. vulgaris shows great potential as a nutritious food ingredient, overcoming existing challenges and optimizing production methods would be crucial for its successful adoption and widespread use.

The Impact of Urban Pollution on Plasmid-Mediated Resistance Acquisition in Enterobacteria from a Tropical River.

Background: The exposure of environmental bacteria to contaminants in aquatic ecosystems accelerates the dissemination of antibiotic-resistance genes (ARGs) through horizontal gene transfer (HGT). Methods: In this study, we sampled three locations along a contamination gradient of a polluted river, focusing on isolating Enterobacteria from the surface waters to investigate the relationship between urban pollution and antibiotic resistance. The genomes of 15 isolates (5 per site) were sequenced to identify plasmid-borne ARGs and their association with resistance phenotypes. Results: Isolates from the site with the highest contamination (Site 3) showeda larger number of ARGs, plasmids, and resistance phenotypes. Notably, one of the isolates analyzed, E. coli A231-12, exhibited phenotypic resistance to seven antibiotics, presumably conferred by a single plasmid carrying 12 ARGs. Comparative analysis of this plasmid revealed its close evolutionary relationship with another IncH plasmid hosted by Salmonella enterica, underscoring its high ARG burden in the aquatic environment. Other plasmids identified in our isolates carried sul and dfrA genes, conferring resistance to trimethoprim/sulfamethoxazole, a commonly prescribed antibiotic combination in clinical settings. Conclusions: These results highlight the critical need to expand research on the link between pollution and plasmid-mediated antimicrobial resistance in aquatic ecosystems, which can act as reservoirs of ARGs.

Geographic Information System and Contamination Indices for Environmental Risk Assessment of Landfill Disposal Sites in Central Saudi Arabia

Landfills pollute air, soil, and surface and groundwater worldwide. The present work aims to assess the environmental risks of three landfills in southern Riyadh using GIS, soil quality guidelines, and contamination indices. GIS tools indicated an increase in the area of the landfill sites with time. The concentration of heavy metals (HMs) in the investigated landfills had the following descending order: Fe (11,532 mg/kg) ˃ Al (5405 mg/kg) ˃ Pb (561.7 mg/kg) ˃ Zn (356.8 mg/kg) ˃ Mn (165 mg/kg) ˃ Cr (74.8 mg/kg) ˃ Cu (42.7 mg/kg) ˃ Ni (22.4 mg/kg) ˃ V (21.8 mg/kg) ˃ As (5.16 mg/kg) ˃ Co (4.08 mg/kg). The highest values of Al, As, Co, Ni, Pb, V, and Zn were recorded from Al Kharj road landfill (RL3). However, the average values of all HMs were lower than those from most worldwide soils and backgrounds, except for Zn, Cu, Cr, and Pb. Results of enrichment factor and statistical analysis indicated deficiency to minimal enrichment and geogenic sources for Al, Co, Mn, and V, while those of As, Cr, Pb, Zn, and Cu showed EF ˃ 2, which might be indicative of anthropogenic activities, especially in RL3. Additionally, very high contamination and a high effects range—median were reported in individual samples, especially for Pb, As, and Zn, indicating frequent adverse effects for these HMs. The difference in contamination for the HMs in the studied landfill sites might be attributed to the difference in the magnitude of input for each metal into the landfill site and/or the difference in the removal rate of each metal from it.

Nursery origin and propagation stage influence the endophytic fungal communities inhabiting grapevine planting stocks

Infection of grapevine trunk disease (GTD) pathogens can occur in nursery and may result in young vine decline in newly established vineyards. We aimed at profiling the causal agents of GTD in California nurseries and explore how the vine propagation processes affect pathogens spread and fungal community dynamics. Plant and environmental samples were collected throughout the plant propagation. For grafted vines, wood tissue samples were collected above the graft union (scion), below the graft union (rootstock) and at the crown (rootstock) and wood necrosis was scored using a 0-3 rating system. We used both a metabarcoding approach using PCR primers custom-designed for GTDs and culturing technique coupled with Sanger sequencing for sample diagnosis. Results showed that mycobiome diversity and composition in vines was significantly influenced by the nursery of origin and the propagation stage. We identified 21 GTD-taxa across all plant samples associated with Petri disease, black foot, Botryosphaeria dieback, Phomopsis dieback and Eutypa dieback. Only 10% of the mother vines cuttings were GTD-pathogens free but co-infection with multiple pathogens became more frequent as the vines progressed through the propagation pipeline. Especially, the incidence of pathogens associated with Petri disease (Phaeoacremonium, Cadophora, Pleurostoma) and Fusarium increased during that time span likely because of high contamination levels in soil and water environments. Wood necrosis at the graft union and crown also increased post grafting and Phaeoacremonium and Fusarium correlated with more necrosis whereas Trichoderma with healthier wood ratings. Our study suggests that nursery practices strongly influence GTD pathogen profile.

Water Quality Assessment and Prevalence of Waterborne Diseases within Chikun Local Government Area, Kaduna State-Nigeria

Study’s Excerpt Water quality and the prevalence of waterborne diseases in Chikun Local Government Area, Kaduna State, were assessed. Microbiological analyses revealed microbial, helminth and protozoan contamination in water sources while Physicochemical analyses revealed heavy metal contamination. There is a need for enhanced water treatment and community awareness for improving water safety and public health in the region. Full Abstract The health and well-being of individuals in a nation are intrinsically tied to the quality of water available for consumption. Access to high-quality water plays a vital role in supporting proper nutrition, ensuring food security, and preventing waterborne diseases. Therefore, this study was carried out to assess water quality and prevalence of waterborne diseases within Chikun Local Government Area, Kaduna State. A cross-sectional study was conducted between January and June 2024. Data were collected through the administration of questionnaires (400 respondents) and laboratory water analysis. Water samples were analyzed from various sources involving boreholes, rivers and wells through composite sampling and physicochemical and microbiological analyses. Results showed samples from Unguwan Maigero and Tricania possessed varying physicochemical properties, while water from Goningora and Nasarawa revealed high turbidity and heavy metal contamination. Chloride levels were below 500 ppm, and sulphate concentrations ranged from 10.76 to 378.3 ppm. Sodium levels ranged from 19.5 to 110 mg/l, and potassium levels exceeded the permissible limit in some samples. Total coliform counts exceeded national limits (zero coliform per 100ml of water), indicating significant microbial contamination. Parasitological analysis indicated helminths and protozoan contamination in non-borehole sources. Findings showed 41% prevalence of waterborne diseases with diarrhea and typhoid. The study indicates that community awareness, appropriate water treatment, surveillance, and monitoring are essentials for assuring the availability and utilisation of safe and high-quality drinking water in Chikun LGA, Kaduna State.

Pollution and Ecological Risk Assessment of Potentially Toxic Elements in Sediments Along the Fluvial-to-Marine Transition Zone of the Don River

The quality of sediments in the mixing zone of river freshwater and marine saline water as an important geochemical barrier for potentially toxic elements (PTEs) remains poorly understood. This study aims to analyze the current pollution with PTEs and associated ecological risks in sediments of the Don River delta and the surrounding area of the Taganrog Bay of the Sea of Azov (Russia). The PTE content was determined in fifty-four collected samples using the WDXRF and assessed using geochemical and ecotoxicological indicators. The source of Cr, Mn, Ni and Pb is mainly river runoff, and Cu, Zn and Cd are from a variety of anthropogenic sources. As shown by the assessment of the geoaccumulation index (Igeo), single pollution index (PI) and contamination factor (CF), these elements are the priority pollutants. According to these estimates, high and very high contamination of sediments in the estuarine zone of the Don River with Cd and Pb was detected in 72–94% and 2–57% of samples, respectively. However, environmental risks are determined almost exclusively by the level of Cd. Total contamination as assessed by the Nemerow pollution index (NPI), modified degree of contamination (mCd) and metal pollution index (MPI) is of concern in 83–98% of the samples studied. The most heavily polluted sediments are in the vicinity of residential areas of the Taganrog Bay. Despite the lower average pollution levels of deltaic sediments, freshwater biota are exposed to higher potential toxic risks of adverse effects by PTE, particularly from Ni and Pb. Thus, the complex hydrological regime and uneven anthropogenic impact predetermine the geochemical state of the sediments of the estuarine zone of the Don River.

Effects of Polycyclic Aromatic Hydrocarbons on Soil Bacterial and Fungal Communities in Soils

Soil organic pollution (such as heavy metals, PAHs, etc.) has caused serious environmental problems, which have resulted in unexpected effects on contaminated soil ecosystems. However, knowledge of the interactions between environmental PAHs and bacterial and fungal communities is still limited. In this study, soil samples from different PAH-contaminated areas including non-contaminated areas (NC), low-contaminated areas (LC), and high-contaminated areas (HC) were selected. Results of toxic equivalent quantity (TEQ) indicated that Benzo[a]pyrene (BaP) and Dibenzo[a,h]anthracene (DBahA) constituted the main TEQs of ∑16PAHs. Incremental lifetime cancer risk (ILCR) assessment revealed that the main pathway of exposure to soil PAHs was dermal contact in adults and children. Furthermore, adults faced a higher total cancer risk (including dermal contact, ingestion, and inhalation) from soil PAHs than children. The microbial community composition analysis demonstrated that soil PAHs could decrease the diversity of bacterial and fungal communities. The relative abundance of Acidobacteriota, Gemmatimonadota, Fimicutes, Bacteroidota, Ascomycota, and Basidiomycota exhibited varying degrees of changes under different concentrations of PAHs. Benzo[a]anthracene (BaA) and Chrysene (Chr) drove the bacterial community composition, while BaP and DBahA drove the fungal community compositions. Co-occurrence network analysis revealed the high contamination levels of PAHs that could change the relationships among different microorganisms and reduce the complexity and stability of fungal and bacterial networks. Overall, these findings provide comprehensive insight into the responses of bacterial and fungal communities to PAHs.

Potential ecological risk assessment of microplastics in environmental compartments in Mexico: A meta-analysis.

Microplastic (MP) environmental contamination has been widely studied in Mexico. However, the evaluation of the associated risk to MPs in environmental compartments is scarce. Therefore, this study addresses this issue using diverse indicators such as the Pollution Load Index (PLI), the Polymer Risk Index (PRI), and the Potential Ecological Risk Index (PERI). The results of a meta-analysis revealed high MP contamination levels in most of the studied compartments, which included marine and estuarine waters, beach sand, freshwater, sediments, and biota. Regarding the risk assessment indicators, PLIs indicated low (56%), dangerous (22%), moderate (12%), and high (10%) levels across compartments. Meanwhile, PRIs displayed concerning values, with 36%, 35%, 20%, and 9% exhibiting dangerous, high, moderate, and low levels, respectively. Thus, high PRI values emphasized the significant rise in MP pollution, largely attributed to high-hazard polymer compositions. Otherwise, PERIs showed low (56%), very dangerous (29%), moderate (6%), high (5%), and dangerous (4%) levels. Thus, the ecological risk in Mexico is widespread and mainly linked to MP abundance, polymer type, environmental matrix, and characteristics of organisms. This study represents the first attempt at MP ecological risk assessment in Mexico, providing crucial insights for developing mitigation strategies to address concerns about MP contamination.

Optimization of the hydrothermal process for simultaneous LiNi0.5Co0.2Mn0.3O2 regeneration and polyvinylidene fluoride (PVDF) decomposition

Nickel‑cobalt‑manganese (NCM) ternary lithium-ion batteries (LIBs), widely utilized in new energy vehicles, inevitably face retirement after prolonged use due to capacity decay and performance degradation. These batteries consist of lithium, nickel, cobalt, manganese, and other metals and organic compounds. Mishandling these batteries can lead to significant environmental harm. Therefore, recycling and reprocessing used ternary LIBs is essential. The conventional hydrothermal method for cathode repair and regeneration has demonstrated broad applicability and remarkable effectiveness in recovering ternary LIBs, indicating promising prospects for application. However, high hydrothermal temperatures and fluorine contamination hinder its practical implementation. This study optimized the traditional hydrothermal method for cathode repair and regeneration to address these challenges by utilizing a reducing environment facilitated by glucose, which lowers the activation energy barrier and reduces the hydrothermal temperature. Additionally, the optimized method degrades the binder polyvinylidene fluoride (PVDF) during the repair and regeneration process, effectively preventing fluorine contamination. Conditional experiments and quantitative analyses using Raman spectroscopy were conducted to investigate the degradation efficiency and pathways of PVDF. The regenerated LiNi0.5Co0.2Mn0.3O2 (NCM523) polycrystalline particles were successfully restored in morphology and structure, exhibiting good specific capacity and cycling stability. This was confirmed through scanning electron microscopy (SEM), laser particle size analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and other analytical methods, alongside electrochemical tests. This study presents a sustainable, cost-effective, and environmentally friendly solution for efficiently recycling and reprocessing ternary LIBs.

Potencial bioindicador de mudas de Cedrela fissilis em áreas contaminadas por cobre

ABSTRACT Soil contamination with toxic metals brings along severe environmental issues. Among these metals, copper (Cu) is harmful to plant development when it reaches high contamination levels in the soil. Thus, identifying species capable of resisting this contamination type helps these sites’ revegetation and decontamination processes. Therefore, the present study aimed to investigate the tolerance of Cedrela fissilis plants to excess Cu through morphophysiological and biochemical variables. C. fissilis seedlings were subjected to five concentrations of Cu (0, 2, 4, 6, and 8 mg L-1). The experimental design was completely randomized, with five treatments and four repetitions. Morphophysiological (number of leaves, shoot height, root length, dry weight, morphological variables of the root system, and leaf area) and biochemical (antioxidant enzymes, lipid peroxidation, hydrogen peroxide concentration, and photosynthetic pigments) traits and Cu accumulated in roots and shoot were evaluated. High concentrations of Cu had a negative effect on the shoot and root dry weight, photosynthetic rate, stomatal conductance, and transpiration rate. Overall, Cu increased the activity of the antioxidant enzymes and lipid peroxidation. Therefore, Cu incidence in the nutrient solution has negatively influenced the biochemical and physiological traits of C. fissilis seedlings to the detriment of their growth. Thus, it was possible to identify sensitive behavior by the investigated species. Because of these features, C. fissilis seedlings can be used as markers for copper-contaminated areas.