Search Results (893)

Wolffia globosa (watermeal) is a potential plant-based food ingredient. This study characterized its nutritional and physicochemical properties, elemental levels, total phenolic content (TPC), total flavonoid content (TFC), DPPH radical-scavenging activity, IL-6 production in H₂O₂-stimulated RAW264.7 macrophages, and preliminary cell-viability responses. On a dry-weight basis, the tested W. globosa sample contained 25.83% protein, 4.56% fat, 16.58% ash, 8.80% crude fiber, and 44.22% carbohydrate. Arsenic and zinc were detected below their limits of quantification, whereas cadmium, copper, and lead were below their method detection limits. All analytical reporting limits were below the corresponding EFSA specification values. The extract had TPC and TFC values of 0.85 ± 0.03 mg GAE/g sample DW and 0.52 ± 0.02 mg QE/g sample DW, respectively, and showed weak DPPH radical-scavenging activity (IC₅₀ = 7.58 ± 0.32 mg DW-equivalent/mL). At 0.1 mg DW-equivalent/mL, the H₂O₂-stimulated extract-treated group showed a lower IL-6 concentration than the H₂O₂-stimulated extract-free model control. Weak reductions in cancer-cell viability occurred only at high concentrations (IC₅₀ values of approximately 38–42 mg DW-equivalent/mL). The biological findings remain preliminary. Overall, the tested sample showed promising nutritional and physicochemical characteristics, low selected-elements levels, and preliminary in vitro responses. Full article

This study investigates the spatiotemporal distribution of heavy metals in urban soils of Thessaloniki, Greece, over a four-year monitoring period (2021–2024). A total of 664 soil samples were collected across diverse land-use types during both wet (winter) and dry (summer) seasons. Soil physicochemical properties were analyzed alongside cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) concentrations. The results reveal distinct, element-specific accumulation dynamics driven by continuous anthropogenic inputs. Statistical and geospatial analyses confirm that Cd exhibits a highly significant, progressive accumulation and spatial expansion toward residential areas. In contrast, Cu and Pb demonstrate a gradual, chronic enrichment, eventually reaching a saturation point where winter precipitation is insufficient to offset summer deposition. Zn presents as a severe but temporally stable contamination burden, anchored to the northwestern industrial–port sector. Furthermore, the alkaline properties of the local urban soils were found to act as an effective sink, immobilizing contaminants and preventing downward leaching. The Geo-accumulation Index (I_geo) confirms a progressive decline in soil quality driven primarily by cadmium, while the other trace elements exhibit persistent, stable profiles. Overall, this study establishes a vital geochemical baseline of total heavy metal loading in Mediterranean urban soils, emphasizing the need for targeted emission controls and future mobile-fraction assessments to guide sustainable urban management. Full article

Sulfur is an essential nutrient involved in plant growth, redox regulation, and responses to environmental stresses. Sulfate transporters (SULTRs) control sulfate uptake and distribution, thereby affecting sulfur availability for metabolic processes and stress adaptation. However, the characteristics and stress-responsive functions of SULTRs in the halophyte Sesuvium portulacastrum remain unclear. In this study, we identified and characterized the SULTR family in S. portulacastrum through phylogenetic analysis, gene structure comparison, conserved motif analysis, promoter characterization, synteny analysis, and expression profiling. A total of 22 SpSULTRs were identified and classified into three subfamilies. Most SpSULTRs contained conserved Sulfate_transp and STAS domains and were predicted to localize to the plasma membrane. Transcriptome analysis combined with qRT-PCR validation revealed that SpSULTRs displayed diverse tissue-specific expression patterns under salt, cadmium, and copper stresses. Of these, SpSULTR3;1 and SpSULTR3;2 showed strong responses to salt stress and were mainly expressed in leaves. Protein interaction predictions suggested that these two transporters may be associated with sulfur assimilation, antioxidant metabolism, and stress-related pathways. These results reveal the structural diversification and stress-responsive characteristics of the SULTR family in S. portulacastrum and provide a basis for further investigation of sulfur transport mechanisms underlying halophyte adaptation. Full article

Sustainable development is seriously hampered by environmental contamination. Heavy metals are perhaps the most significant of these silent pollutants because of the poisoning they inflict on different ecosystems, particularly water systems, as well as the direct threat they pose to the safety of such systems and the ensuing health issues that affect people and other living things. The goal of the current work is to ascertain how effective peanut (Arachis hypogaea) hulls are as easily accessible and reasonably priced adsorbent materials for the ion adsorption of various heavy metals, including lead, copper, zinc, and cadmium. A series of variables, such as pH, temperature, retention time, shape, quantity of adsorbent and particle size, were investigated to reach the optimal conditions for the biosorption process, which were achieved at pH 6 (close to pH-zero charge), a temperature of 40 °C, a retention time of 60 min, an adsorbent dose of 5 g/L, and a particle diameter of 0.1 mm. Experiments showed that lead had the highest treatment rate, approximately 95%, followed by zinc, copper, and cadmium. The results were confirmed and validated using SEM analysis to identify the morphology of the hulls before and after treatment, FTIR spectroscopy to investigate the functional groups responsible for binding to the metal ions, and further supported by kinetic isotherms of the adsorption behavior, which matched the Langmuir and Freundlich models. Nevertheless, the results of the batch experiment were employed by designing a laboratory treatment unit for municipal wastewater containing beads of alginate-immobilized Arachis hypogaea hulls. The designed laboratory unit was effective in treating unacceptable levels of heavy metals in some municipal wastewater from the local drainages of Ramadi City, Iraq. Overall, the study’s findings suggested that peanut hulls could be used to mitigate toxic metal pollution in an eco-friendly manner that guarantees the accomplishment of the Sustainable Development Goals pertaining to future generations’ right to the safe use of water resources. Full article

Background/Objectives: Circulating trace-element differences have been reported in neurodegenerative disorders, but data in multiple system atrophy (MSA) are scarce. We compared eleven trace elements and two operationally defined exploratory composite indices between patients with MSA and controls. Methods: This case–control study included 30 patients with MSA and 30 frequency-matched controls. Eleven elements were quantified by ICP-MS. The raw Metal Burden Index (MBI; mean of aluminum, lead, cadmium, manganese, and arsenic) and Neurotoxic Metal Score (NMS) were calculated. Component-level decomposition was performed, and an aluminum-excluded index and component-standardized MBI (MBIz) were evaluated as sensitivity analyses. Results: Patients with MSA had higher aluminum and copper and lower iron and zinc than controls (all p < 0.001, Bonferroni-corrected; absolute Cohen’s d = 3.39–3.85). The raw MBI was higher in MSA (p < 0.001, d = 1.38) and remained associated with MSA status after age/sex adjustment (OR = 5.50, 95% CI 2.25–13.47 per 1-SD increase). Aluminum accounted for 114.6% of the MBI difference; the aluminum-excluded index did not differ. MBIz was higher in MSA (p < 0.001, d = 0.95). Exploratory ROC analyses showed apparent separation for raw MBI, aluminum, and copper without establishing validated diagnostic thresholds. No statistically significant correlations with disease severity or duration were observed; estimates were imprecise. Conclusions: MSA was associated with higher serum aluminum and copper and lower iron and zinc. The raw MBI predominantly reflected the aluminum signal; its incremental value beyond individual elements remains unproven. Findings require validation in disease-control and multicenter cohorts. Full article

Zingiber officinale (ginger) is a high-value crop with significant nutritional benefits, but it is susceptible to food hazards, including mycotoxins and heavy metals. Fifty-one ginger samples were collected along the value chain in Kaduna State (local government areas: Jaba, Kachia and Zango) and 44 samples obtained from markets in Oyo State (local government areas: Ibadan North, Ibadan Northeast, Ibadan Northwest, and Ibadan Southwest). The incidence of aflatoxins (B1, B2, G1, and G2) and heavy metals (mercury, cadmium, lead, copper, zinc, and chromium), as well as risk assessments, were determined. Half (50%) of the samples from Kaduna contained aflatoxins and all (100%) of the samples from Oyo State contained aflatoxins. On average, 18 to 60% of split-dried samples and 17 to 83% of fresh from Kaduna exceeded 10 ng/g total aflatoxin concentration. In Oyo State 67 to 100% of the split-dried samples exceeded 10 ng/g and 100% of both fresh and milled samples exceeded 10 ng/g total aflatoxins. The estimated probable daily intake of mercury (0.572 mg/kg bw/day) exceeded the limit of 0.23 mg/kg bw/day from Kaduna samples, whereas others were within the tolerable limits. Lead, which has no defined tolerable daily intake, was not detected in Kaduna State samples. In Oyo State samples, lead was detectable with an estimated limit of 0.007 mg/kg bw/day; whereas, the others were within the limit. The estimated probable daily intake (PDI) of aflatoxin B1 was estimated at 4.1 μg/kg bw/day and 1.5 μg/kg bw/day from Oyo State and Kaduna State samples, respectively. The provisional maximum tolerable daily intake (TDI) for aflatoxins is 2 μg/kg bw/day. The use of probiotics was explored for the detoxification of aflatoxin-spiked ginger samples (at 50 ng/g). Lactiplantibacillus plantarum ATCC 8014 (LP) and Lactobacillus helveticus ATCC 15009 (LH) reduced aflatoxin concentrations by 50% when used alone or together at the end of a 120 h incubation period. The study highlights the incidence and risk of exposure to multiple toxicants in ginger and the need for management of aflatoxins and heavy metals along the ginger value chain. Full article

Background: Drilling slurry, a waste material generated during natural gas extraction, requires careful chemical characterization to determine its environmental hazard classification and inform appropriate management strategies. Methods: This study characterizes the drilling fluid used as raw material and the resulting drilling slurry waste, using a case study sample from the Buzău extraction area (Well 1 Florica, S.N.G.N. Romgaz S.A.), including total composition analysis, three-stage leaching tests, linear regression of leaching kinetics, and standardized geoaccumulation indices (Igeo, CF, PLI). Results: Total composition analysis confirmed low heavy metal concentrations (Cd = 0.02, Cr = 0.05, Pb = 0.64, Zn = 2.82 mg/kg dry matter). All leachate parameters remained below non-hazardous waste thresholds (Order No. 95/2005), with safety factors of 20–100× for regulated metals and 1.2–2.7× for chlorides, sulphates, and dissolved organic carbon. Standardized pollution indices confirmed Class 0 (unpolluted) status for all five metals, with a composite Pollution Load Index of 0.0124. Leaching regression analysis revealed dissolution-controlled release for chlorides, sulphates, and zinc (R² > 0.93) versus matrix-retention behavior for copper, nickel, cadmium, and chromium. Comparative analysis showed horizontal drilling generates approximately 146% more waste volume than conventional vertical drilling (170 m³ versus 69 m³ at 2100 m depth). Conclusions: The analyzed drilling slurry meets non-hazardous waste classification with substantial safety margins, corroborated by three independent analytical frameworks. Waste minimization strategies and biodegradable fluid substitution offer practical pathways to reduce the environmental footprint of natural gas drilling operations. Full article

Wild boars (Sus scrofa) are reliable bioindicator species for assessing environmental pollution. In this pilot study, we measured concentrations of arsenic (As), cadmium (Cd), copper (Cu), selenium (Se), zinc (Zn), and lead (Pb) in liver, diaphragm, and testicular tissues from wild boars collected across seven districts of Avellino province (liver/diaphragm: n = 87; testicles: n = 50). Pb reached its highest median value in the diaphragm (0.43 mg/kg w.w.; maximum 14.80 mg/kg), while Cd showed a pronounced affinity for hepatic tissue (median 0.15 mg/kg; maximum 0.62 mg/kg). Zn was the most abundant element overall, particularly in the diaphragm (median 20.51 mg/kg; maximum 46.81 mg/kg). Se concentrations were generally below the detection limit (<0.001 mg/kg), with only occasional outliers. Sex-related differences were evident: males accumulated more Pb in the liver, while females had higher levels of Cd and As. Spatial patterns identified AVMFS009 and AVAR009 as hotspots for Cu, Zn, and Cd, while AVCP003 emerged as the main hotspot for As. Overall, the results reinforce the role of wild boars as effective bioindicators in southern Italy. Full article

Background/Objectives: Heavy metals are environmental hazards that are recognized as neurotoxic agents that may impair olfactory pathways in susceptible individuals. This study aimed to determine the concentrations of cadmium (Cd), arsenic (As), lead (Pb), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), iron (Fe), and mercury (Hg) in the nasal mucosa and secretions of patients diagnosed with nasal septal deviation, nasal polyposis, or chronic rhinosinusitis, and to investigate their associations with olfactory function, nasal airflow, and pathohistological changes in the nasal mucosa. Methods: This prospective study included 97 adult patients who underwent nasal surgery. We used the Smell Diskettes Olfaction Test to assess olfactory function and rhinomanometry to evaluate nasal airflow resistance. Nasal mucosal tissue samples were collected intraoperatively. Heavy metal concentrations were analyzed using inductively coupled plasma mass spectrometry and atomic absorption spectrometry. Results: Preoperative olfactometry scores in patients with olfactory dysfunction differed to those in patients without olfactory dysfunction (3.4 ± 1.3 vs. 4.1 ± 1.2). Inferential analysis of heavy metals and olfactometry revealed that Cr, Fe, and Pb concentrations were negatively associated with olfactory performance before exposure (Cr: β = −0.12, p = 0.018; Fe: β = −0.08, p = 0.009; Pb: β = −0.10, p = 0.048). Rhinomanometry parameters showed positive associations with olfactory function, independently of age, sex, and groups of patients with or without olfactory dysfunction (R1: β = 0.45, p < 0.001; R2: β = 0.30, p = 0.003). Stepwise regression identified Fe, Pb, and Cr as the strongest predictors of olfactory dysfunction. The adverse effects of Fe and Pb exposure were significantly amplified with age. MANOVA revealed significant differences in heavy metal concentrations across pathohistological categories (Wilks’ Lambda = 0.038, p < 0.001). Carcinoma tissue exhibited significantly higher Cr concentrations, whereas precancerous lesions exhibited increased Cd concentrations. Conclusions: Cr, Fe, and Pb accumulation in nasal mucosa secretion is significantly associated with impaired olfactory function and pathohistological changes. Prolonged exposure to environmental heavy metals may affect olfactory function in the elderly population. Full article

Heavy metals (HMs) such as copper (Cu), lead (Pb), cadmium (Cd), chromium (Cr) and zinc (Zn) from industrial activities are discharged into nearby water resources after treatment. In the present study, the potential of utilizing chemically activated carbon derived from water hyacinths as a sustainable and low-cost adsorbent for heavy metal removal from industrial wastewater from the Nakawa industrial area, Uganda was investigated. The measured physicochemical parameters of wastewater (temperature, pH, electrical conductivity, total dissolved solids, turbidity, dissolved oxygen, chlorides and total hardness) varied significantly among the three sampled sites (p < 0.05), except for pH. Similarly, the concentration of the HMs in the samples (0.54 ± 0.04 mg L⁻¹ for Cr to 93.54 ± 0.07 mg L⁻¹ for Pb) varied significantly between sites (p < 0.05), exceeding the maximum permissible limits of Cd, Pb, Cr, Cu and Zn specified in the National Environment Standards for Discharge of Effluent into Water or Land. The water hyacinth biomass was activated using eggshell powder and phosphoric acid, followed by thermal treatment. Characterization using Fourier-transform infrared spectroscopy and scanning electron microscopy confirmed that there was improvement in its surface functionality and porosity post activation. Batch adsorption experiments indicated that optimal removal of the HMs was achieved at pH 4–5, contact time of 90 min, and 1.0 g of adsorbent. Maximum adsorption capacities of Pb, Cd, Cu, Cr and Zn were in the range of 1.04–8.36 mg g⁻¹. Under the optimized conditions, the eggshell-activated carbon derived from water hyacinths had removal efficiencies of 91.2 ± 9.1% (range: 71.3–100%). Adsorption occurred through both monolayer and multilayer coverage, as indicated by the experimental data which fitted well to the Freundlich isotherm (Cd²⁺, Pb²⁺, Zn²⁺ and Cu²⁺ ions) and Langmuir isotherm model (Cr³⁺ ions). These results support the potential of water hyacinth-derived activated carbon as an ecofriendly alternative for treating low concentrations of these HMs in industrial wastewater. Full article

Groundwater is vital to subsurface ecosystems and to maintaining water supplies for human and environmental needs. Heavy metal pollution of water bodies poses a significant threat to environmental health and human well-being. In this paper, a detailed spatiotemporal analysis of heavy metal pollution at a network of 35 sampling sites is presented for the summer, autumn, and winter seasons. The water samples were analyzed based on the concentration (μg/L) of eight priority metals, such as Lead (Pb), Mercury (Hg), Cadmium (Cd), Arsenic (As), Chromium VI (Cr-VI), Copper (Cu), Zinc (Zn), as well as Iron (Fe). Measuring contamination levels, identifying space hotspots, and explaining seasonal variations were the key tasks. The results show that Fe, Zn, and Cu concentrations are consistently high across seasons, with mean values ranging from 234.3 to 253.2 µg/L (Fe), 163.2 to 175.6 µg/L (Zn), and 107.0 to 109.2 µg/L (Cu), indicating a widespread geogenic or diffuse source. The most significant seasonal deviation was observed in the fall when there were unusually high levels of Cd and Hg, with mean concentrations reaching 0.476 µg/L and 0.312 µg/L, respectively, suggesting a strong seasonal contamination event or mobilization process. The spatial analysis showed that the locations (e.g., L6, L8, L10, L28, L29) exhibited common hotspots for different metals, with maximum concentrations reaching up to 793.3 µg/L (Fe), 602.3 µg/L (Zn), and 508 µg/L (Cu). Principal Component Analysis (PCA) effectively separated seasonal trends and classified metals into anthropogenic (Pb, Cd, Hg, Cr (VI)) and geogenic/diffuse (Fe, Zn, Cu) groups. The health risk assessment indicated no significant non-carcinogenic risk, although children are more vulnerable, while arsenic levels in winter approached the upper acceptable carcinogenic limit (up to 1.1 × 10⁻⁴). Overall, the study highlights the importance of multi-seasonal monitoring by capturing temporally abrupt contamination events and provides a novel integrated framework that combines seasonal analysis, spatial hotspot identification, and multivariate techniques, distinguishing it from conventional single-season or non-integrated studies. Full article

Freshwater ecosystems are increasingly exposed to metal contamination arising from natural and anthropogenic activities, potentially affecting fish physiology and ecosystem health. However, limited information is available regarding metal accumulation and associated biological responses in fish populations from Dukan Lake, northern Iraq. Therefore, this study investigated metal concentrations in water and tissues of common carp (Cyprinus carpio) and evaluated their relationships with selected fish health indicators. Water and fish samples were collected monthly from Dukan Lake, and a total of 60 fish were classified into three length groups (20–29 cm, 30–39 cm, and 40–49 cm). Metal concentrations in water, liver, and gonad tissues were analyzed using ICP-OES, while condition factor (CF), gonadosomatic index (GSI), and hepatosomatic index (HSI) were used to assess fish physiological condition. Sodium (Na), magnesium (Mg), potassium (K), iron (Fe), zinc (Zn), and barium (Ba) were detected in both water and fish tissues, with concentrations in water ranging from 50 to 7069 μg/L. In contrast, chromium (Cr), manganese (Mn), nickel (Ni), selenium (Se), silver (Ag), cadmium (Cd), antimony (Sb), lead (Pb), copper (Cu), and arsenic (As) were below detection limits. Biometric analysis revealed significant differences (p < 0.05) in the gonadosomatic index (GSI) among fish length groups, indicating size-dependent reproductive development. However, no significant relationship was observed between fish length and either the CF or HSI, suggesting relatively stable somatic condition or liver status across size classes. Correlation analysis showed no significant associations between water metal concentrations and CF or GSI. A significant positive correlation was identified between Zn concentration and HSI in the 30–39 cm length group, indicating a possible link between Zn exposure and hepatic physiological response. The findings indicate that essential elements dominate the metal profile in Dukan Lake, with limited evidence of toxic metal contamination. No major adverse effects on the general condition of the fish were observed. These results contribute to understanding metal bioaccumulation patterns and their implications for fish health in freshwater ecosystems. Full article

Chronic oxidative stress is a molecular hallmark of cardiovascular–kidney–metabolic (CKM) syndrome, yet its contribution to CKM-associated anemia beyond erythropoietin deficiency and iron restriction is poorly characterized. The serum copper-to-zinc (Cu/Zn) ratio reflects impaired Cu/Zn-SOD1 antioxidant capacity and inflammatory trace-element imbalance, but its relationships with circulating redox biomarkers and its hematological relevance in CKM syndrome has never been explored in a community-dwelling cohort of older adults. We analyzed 2391 NHANES 2011–2016 participants ≥ 50 years of age with CKM stage I-IV. To explore whether the serum Cu/Zn ratio was associated with oxidative stress and immunomodulatory biomarkers as well as with the odds of anemia, we used survey-weighted Spearman correlations, linear regression (outcome: hemoglobin), and logistic regression (outcome: anemia); multivariate models were adjusted for a panel of antioxidant or immunomodulatory biomarkers (selenium, vitamin D), pro-oxidant biomarkers (lead, cadmium, cotinine, uric acid), red cell distribution width (RDW) as a composite biomarker of erythrocyte stress, neutrophil-to-lymphocyte ratio (NLR), CKM stage, and comorbidities. The molecular targets of the nine biomarkers were mapped onto a protein–protein interaction network using the STRING database v12.0 to contextualize regression findings within a systems biology framework. Anemia was present in 205 participants (8.6%). The Cu/Zn ratio was inversely correlated with the antioxidant marker selenium (r = −0.19; p < 0.001) and positively correlated with the pro-oxidant markers RDW (r = +0.21; p < 0.001) and cadmium (r = +0.10; p < 0.001), consistent with its role as a hub within the CKM redox network. In fully adjusted models, a higher Cu/Zn ratio was independently associated with prevalent anemia (OR = 2.94; 95% CI: 1.61–5.37) and lower hemoglobin (β = −0.55 g/dL); among included biomarkers, selenium and cadmium were independently protective (OR = 0.76 per 10 µg/L and 0.23 per µg/dL, respectively), and RDW and uric acid were independently harmful (OR = 2.20 per 1% and 1.33 per mg/dL, respectively). The Cu/Zn ratio correlated with both antioxidant depletion and pro-oxidant accumulation in CKM syndrome and was independently associated with anemia within this oxidative network. Together with selenium, cadmium, RDW, and uric acid, it defines an oxidative stress-driven hematological pathway that may contribute to the development and progression of anemia in patients with CKM syndrome. Full article

Rapid detection of heavy metals is vital for monitoring surface water contamination and preventing environmental and health risks. Traditional detection methods for metals such as lead and copper often require sophisticated, costly instrumentation, limiting their use in routine analyses. To address this challenge, we developed a cost-effective fluorescence-based approach using semiconductor quantum dots (QDs) as nanosensors for metal ion detection. The QDs were synthesized directly in aqueous medium through a reflux-assisted process employing cadmium precursors, selenium, thioglycolic acid (TGA), and branched polyethyleneimine (PEI, Mw ~25,000) as stabilizing agents. Structural analysis revealed nanoparticles with diameters below 5 nm, spherical morphology, and a zinc blende (face-centered cubic) crystalline structure. Optical characterization by UV–Vis, photoluminescence (PL), and FTIR spectroscopy confirmed effective surface functionalization and strong quantum confinement. PEI-capped QDs exhibited enhanced colloidal stability and showed pronounced fluorescence quenching in the presence of Pb²⁺ ions, indicating high sensitivity and selectivity toward lead. Both TGA- and PEI-capped QDs also demonstrated moderate responses to Co²⁺ but negligible interaction with Sn²⁺, confirming ion-specific detection. Overall, this study demonstrates that surface-engineered QDs constitute a simple, accessible platform for selective detection of toxic metals, with promising applications in environmental monitoring and water quality assessment. Full article

Heavy metals such as copper and zinc serve as essential trace elements for photosynthetic organisms at appropriate concentrations. However, at elevated levels, these metals (along with non-essential metals like chromium, lead, mercury, and cadmium) exert severe toxic effects on aquatic life. Heavy metal toxicity primarily relates to oxidative damage in living systems through a direct increase in reactive oxygen species (ROS) and reduction in cellular antioxidant capacity. Previous research on algae of different types with different coverings led us to complete the comparative framework. For this purpose and to assess biotechnological potential, we investigated chromium effects on Euglena gracilis, which possesses a unique pellicle covering, to determine whether it could serve as a chromium biosensor or bioremediation agent. Using Raman spectroscopy and absorption microspectrophotometry (MSP), we found that chromium concentrations of up to 500 μM had no effect on Euglena chlorophyll or carotenoid profiles, consistent with the pellicle preventing chromium entry and protecting the photosynthetic apparatus. However, concentrations > 10 μM severely inhibited growth through extracellular interference with essential nutrient utilization (ammonium phosphate and vitamin B₁₂). Growth inhibition was reversible upon transfer to fresh medium, confirming that cellular machinery remained intact. These results suggest that E. gracilis cannot serve as a chromium biosensor (photosynthetic apparatus unaffected) or bioremediation agent (no chromium internalization), but its ability to maintain photosynthetic functionality in chromium-contaminated environments suggests the potential for alternative applications in polluted water biomass production. Full article