The Chodha Lake sediment core of Korba district, Chhattisgarh was investigated for 10 potentially toxic elements to asses metal pollution, their sources, past apportionment and eco-environmental risks. Geochemical analysis was performed with the help of X-ray Fluorescence spectrometer. The discrete sources of the potentially toxic elements were distinguished mainly using principal component analysis and factor analysis. The core sediments show elevated concentrations of Potentially toxic elements, with notable enrichment in Fe, Cr, Mn and Co, while Cu, V, Zn and Ni also exhibit relatively high levels. Cu, V, Pb, and Cr pollution was mainly related to the adjoining coal productions, particularly burning of coal and associated fly ash. The contamination of Mn and Fe may be attributable to coal mine tailings and allied rock fragments. On the contrary, Al, Ni and Zn indicate their geogenic origin derived largely from the weathering and erosion of soils of the study region. The various levels of contamination are interpreted based on the pollution indices. Most of the elements indicated their moderate enrichment in the sediment core, whereas moderate to substantial levels of contamination was exhibited by Fe and excessive contamination by Cobalt. The moderate to substantial degree of pollution based on the Index of geo-accumulation was revealed by Fe, Zn and Mn. However, all the core sediments confirm the consistent low potential ecological risk to aquatic life.
In the present study, characterisation of (nano-)biochars(NBCs) derived from agro-wastes using BET, CHNS/O, TGA/DSC, FTIR, SEM, TEM, AAS, and ICP-MS analyses confirmed physical integrity, crystalline and homogenous nature of biochars, including their elemental composition, moisture, and ash content, nanosized particles (25-100 nm), and the presence of functional groups. Maximum adsorption capacity of NBCs derived from bagasse, maize stalk, and paddy straw was found to be 66.10 ± 1.06, 75.61 ± 1.28, 73.04 ± 1.04 mg/g for lead, and 29.05 ± 0.96, 66.07 ± 1.15, 61.76 ± 1.02 mg/g for cadmium, which indicated that maize stalk biochar is the most effective. These NBCs effectively remove chromium in the range of 24.6-53.8 mg/g at a lower pH of 2.2 due to electron-donating groups; however, they were ineffective at a higher pH value of 7 because of electrostatic repulsion with negatively charged functional groups and differences in chemical speciation, surface charge, and redox potential. Pyrolysis enhanced the properties of biosorbents by increasing their porosity, surface area, and concentration of key minerals suitable for ion exchange. None of the NBCs removed ammonia and nitrite effectively. NBCs have potential applications for heavy metals removal and mitigation of stresses for climate-resilient agriculture due to their stability, recalcitrance, and water retention capacity.
Microplastic (MP) pollution is a prevalent environmental concern, omnipresent in soil, water, and air. The Indian Himalayan riverine systems are increasingly threatened by MP contamination, seeking dire attention. This study investigates not only the occurrence, abundance, and characterization of MPs in the rivers of Dehradun, focusing on two tributaries of the Ganges (Rispana and Bindal) and the Yamuna (Tons), but also on their temporal variation during pre- and post-monsoon seasons. A difference in the presence of MP pollutant in the upper Ganges (Rishikesh) versus its lower tributaries-Rispana and Bindal was observed, which was almost nil in the upper regions and detectable in the latter. Water chemistry, including physicochemical analysis and heavy metal analysis, along with Carbon, Nitrogen, and Phosphorus, was estimated and compared at each site. MP abundance ranged from 0.1 to 10.95 particles/L and was consistently higher in the pre-monsoon period. Colored MPs were dominant across sites (65.66%, 86.57%, and 91.72%), with fibers being predominant, followed by fragments and films. FTIR and Raman of MPs revealed primarily polyethylene, polypropylene, polystyrene, and polyvinyl chloride. A glimpse of the presence of heavy metals and microorganisms on the MPs' surface (plastisphere) was depicted via light microscopy and SEM-EDS. Raman spectroscopy revealed MPs were laden with detergent, as hinted by pigmosol detection-a detergent component. Thus, MPs act as carriers for contaminants and microbial colonization, potentially altering the riverine ecosystem dynamics. Overall, the study underscores the ecological risks of MPs in Himalayan riverine systems and calls for targeted mitigation and management strategies.
Nitrate pollution in the Ling River Basin has emerged as a pressing environmental issue requiring immediate attention. To effectively prevent and control nitrogen pollution in the watershed, this study systematically investigated the sources, migration and transformation mechanisms of nitrate in surface water through an integrated approach combining hydrochemical analysis, nitrogen and oxygen isotope techniques, and a Bayesian mixing model (SIAR). The results indicate that the dominant anion in the water is HCO2−, while Ca2+ is the predominant cation, classifying the hydrochemical type as HCO3–Ca.Mg, with the water exhibiting a slightly alkaline nature. The distribution patterns of hydrogen and oxygen isotopes (δD-H2O and δ18O–H2O) suggest that atmospheric precipitation is the primary source of surface water recharge. Nitrate concentrations remained relatively stable across the wet, normal, and dry seasons. Isotopic analysis of nitrogen and oxygen further revealed mixed sources of nitrate, including soil nitrogen, chemical fertilizers, domestic sewage, and atmospheric deposition. Among these, nitrification is the dominant process in the nitrogen cycle of the basin, whereas denitrification plays a minor role. Quantitative analysis based on the SIAR model showed slight seasonal variations in the contribution rates of nitrate sources: in the wet season, soil nitrogen, chemical fertilizers, domestic sewage, and atmospheric deposition accounted for 50.0%, 23.0%, 17.3%, and 9.7%, respectively; in the normal season, the contributions were 50.0%, 25.9%, 15.0%, and 9.1%, respectively; and in the dry season, 54.6%, 18.8%, 17.8%, and 8.8%, respectively. Therefore, soil nitrogen and chemical fertilizers are identified as the primary sources of nitrate pollution in the Ling River Basin. This study provides critical theoretical support for the control of agricultural non-point source pollution and the protection of aquatic environment.
Heavy metal pollution was surveyed in 2019 and 2021 in cultivated soils from suburban areas, industrial surroundings, and main agricultural lands on the south bank of Taihu Lake. Overall, based on the Chinese national soil environmental quality standard grade II criteria, 21.71, 6.98, 0.78, and 0.78% of suburban and industrial surrounding soils exceeded the standards for mercury (Hg), cadmium (Cd), nickel (Ni), and copper (Cu), while those of main agricultural soils were 4.40, 4.98, 13.60, 5.41%, respectively. The comprehensive pollution indices of soils in the suburban and industrial surrounding area were 0.696 and 0.660, respectively. In contrast, the comprehensive pollution index was 0.648 in soils that were far from the point pollution sites (CK). For locally produced rice grains, the proportions of samples exceeding the Chinese National Food Safety and Health Criteria standards were 12.06% for Hg, 10.64% for Cd, and 17.73% for Zn. Overall, heavy metal pollution was more severe in soils within the suburban areas than the other areas. The survey in 2021 showed that the comprehensive pollution indices of soils in vegetable base, grain function area, modern agricultural park, long-term application of organic manure were 0.748, 0.685, 0.618 and 0.662, respectively. Therefore, suburban area was a priority for preventing and remediating heavy metal pollution, and vegetable bases were the key areas of heavy metal pollution in farmland.
Organic ultraviolet filters (OUVFs) used as ingredients in sunscreens, personal care products (PCPs) and industrial products are persistent, bioaccumulative contaminants of growing concern. Information on the occurrence and health risk assessment of OUVFs in fish from freshwater environments in Nigeria is lacking. We investigated the occurrence and potential health risk of four OUVFs (benzophenone-3 (BP-3), 4-methylbenzylidene camphor (4-MBC), avobenzone (AVO) and ethylhexyl methoxycinnamate (EHMC)) in six different fish species from Dandaru River and Eleyele Lake in Ibadan, Nigeria. A modified QuEChERS extraction, in combination with a dispersive solid phase extraction (d-SPE) clean-up, was used and instrumental analysis was performed by high-performance liquid chromatography. Human health risk was evaluated for three different age groups (adult, children and infant) using standard models and indices. The concentration levels of target OUVFs (35.07-44.68 ng/g for BP-3, 40.19-48.88 ng/g for 4-MBC and 31.79-45.29 ng/g for AVO) were quantified in the fish samples from both water bodies. Hazard index (HI) values of target OUVFs for the consumption of fish collected from Dandaru River and Eleyele Lake ranged from 0.058 to 0.669 and 0.056-0.867, respectively. The HI values obtained for all the investigated fish species were below safety thresholds for all age groups, suggesting non-carcinogenic risk was not evident. The findings emphasize the need for sufficient regulation of OUVFs usage in Nigeria and their discharge into the environment to avoid potential health risk to humans.
Microplastics (MPs) are emerging pollutants posing ecological and physiological threats to aquatic organisms. This study investigates the organ-specific distribution and morphological characteristics of MPs in Tor putitora (Golden Mahseer) collected from Bhimtal Lake, Ladhiya River (Chalthi), and Pancheshwar (confluence of the Kali and Saryu rivers) in Uttarakhand, India, from November 2024 to April 2025. Thirty specimens from each site were analyzed for MP contamination in the gill, gastrointestinal tract (GIT), and muscle tissues using digestion with KOH and microscopic identification. Particle identification was based on visual and morphological criteria, and polymer confirmation by FTIR or Raman spectroscopy was not performed. Functional groups were categorized by morphology, color, and size. The gastrointestinal tract (GIT) exhibited the highest MP abundance (mean ± SD = 5.53 ± 4.26 items/individual), followed by gills (3.50 ± 2.58) and muscle (0.08 ± 0.02). Fibers were the dominant morphology (49.6%), followed by fragments (27.9%) and pellets (22.5%). Black and blue particles accounted for over 74.4% of all MPs, while most particles (71.3%) were ≤ 500 µm. Significant variation ([Formula: see text]) among organs suggests that both respiratory and dietary exposure routes are involved. The predominance of fibers and small-sized MPs suggests possible influence from textile, domestic, and fishing-related activities. These findings highlight the need for organ-level assessments in comprehending the bioaccumulation of MPs in Himalayan freshwater fish.
The environmental fate of fluopyram was evaluated through laboratory dissipation, field dissipation, and soil column leaching studies using representative Indian soils. In vitro dissipation of technical-grade fluopyram (5 mg/kg) was investigated in six soils under aerobic conditions. Fluopyram dissipated slowly, with ~27-33% dissipation of the initial amount after 120 days of incubation. Dissipation followed biphasic kinetics best described by combined first-order and double first-order in parallel (DFOP) models, with estimated DFOP slow-phase half-lives ranging from 363 to 676 days. Under field conditions in sandy loam soil, fluopyram dissipated more rapidly, with ~60-75% dissipation within 90 days following application of 34.48% SC fluopyram at 0.5, 1, and 2 kg a.i./ha. Dissipation again followed biphasic, concentration-dependent kinetics, with DFOP slow-phase half-lives of 54, 130, and 252 days for the respective doses. Soil column studies showed soil-dependent mobility after simulated rainfall (~600 mm), with cumulative leaching of 56.5-64.4% in clay loam soil but negligible movement in clay soil. Based on relative mobility factors, fluopyram was classified as slightly to moderately mobile, indicating persistence combined with variable leaching potential in different soils. Overall, fluopyram exhibited high persistence and moderate mobility, indicating potential long-term soil exposure and possible subsurface transport under favourable conditions.
Direct uptake of an element from water by an aquatic organism and its retention, leading to a higher concentration than in its surrounding water, is an environmental concern known as bioconcentration. It occurs when an organism absorbs a substance faster than it is eliminated by various metabolic processes, such as catabolism and excretion. A bioassay experiment was performed to determine the 96-hour LC50 of cadmium chloride (CdCl2), a heavy-metal salt. For experimentation, pre-acclimated Limnodrilus hoffmeisteri worms were divided into eleven treatment groups (T1 through T11) and a control group (C), each of 50 number of individuals and were exposed to 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, 2.5, 2.75 and 3.0 mg/L cadmium concentrations respectively for 96 h under semi-static condition in a closed-circuit flow-through system with complete renewal of water with the respective relevant cadmium concentration after 48 h. Post-exposure cadmium content per unit amount of tissue samples and of residual water samples was measured with atomic absorption spectrophotometry (AAS). Probit analysis revealed the 96-hour LC50 value of cadmium against L. hoffmeisteri as 1.002 mg/L. The outcome of this study established a low BCF for the experimental species for cadmium, indicating a positive correlation between BCF and exposure concentration and demonstrating the inherent bioconcentration nature of cadmium in L. hoffmeisteri. A gradual declining trend in cadmium content of the whole body was observed at exposure to a cadmium concentration higher than 2.0 mg/L. Concurrent autotomy of the caudal part of the organism has also been observed at this exposure level. Cadmium content of the autotomized tail has been estimated significantly (P < 0.05) higher. It is concluded that autotomization is a defensive mechanism evolved by L. hoffmeisteri to reduce the body's heavy metal load and, hence, toxicity, thereby serving as an indicator species.
Cytochrome P4501A (CYP1A) is a widely used biomarker of environmental stress in fish, primarily associated with xenobiotic metabolism but also responsive to broader changes in water quality. This study provides a region-specific, field-based assessment of hepatic CYP1A responses in Cyprinus carpio in relation to nutrient enrichment across freshwater lakes of the North-Western Himalayas. Fish and water samples were collected monthly over two consecutive years from four lakes representing contrasting trophic conditions Viz Dal, Wular, Manasbal, and Nilnag along with laboratory-maintained control fish. Hepatic CYP1A concentrations were quantified, and concurrent measurements of total phosphorus, nitrate-nitrogen, ammonical nitrogen, dissolved oxygen, temperature, and pH were conducted.CYP1A levels showed pronounced spatial and seasonal variability, with significantly higher concentrations in fish from nutrient-enriched lakes, particularly Dal and Wular, compared to less impacted lakes and laboratory controls. These lakes were characterised by elevated nutrient concentrations and comparatively lower dissolved oxygen levels, reflecting eutrophic conditions. To appropriately address repeated monthly sampling and non-independence of observations, linear mixed-effects models were applied, incorporating lake and season as fixed effects and sampling event as a random effect. Model outputs indicated that total phosphorus and nitrate-nitrogen were significant predictors of CYP1A variation after accounting for seasonal and site-specific effects, whereas ammonical nitrogen showed no independent influence. The results suggest that nutrient enrichment indirectly modulates CYP1A expression through altered environmental conditions such as oxygen availability and metabolic stress rather than direct contaminant exposure alone. Overall, this study demonstrates the utility of CYP1A as an integrative biomarker of ecological stress under eutrophic conditions and highlights the importance of mixed-effects modelling in long-term freshwater biomonitoring.
The aims were to evaluate the tolerance of Typha domingensis and the changes in the internal morphometric parameters of roots exposed to different Cr(III) and Cr(VI) concentrations in Floating Treatment Wetlands (FTWs). FTWs were exposed to 5 and 10 mg L- 1 Cr(III), and 5 and 10 mg L- 1 Cr(VI). Also, a Biological Control (BC) without Cr addition was used. Roots were the main Cr accumulator organ. Both Cr species significantly modified the root morphology of T. domingensis. The highest cross-sectional areas (CSA) of roots, and metaxilematic vessels were observed in 5 and 10 mg L- 1 Cr(III) treatments. The lowest CSA and number of vessels (NV) were observed in 5 and 10 mg L- 1 Cr(VI) treatments. The lowest chlorophyll concentrations and growth rates were determined at 10 mg L- 1 Cr(VI). Metaxylem vessels presented a disordered arrangement. Cr mapping from 10 mg L- 1 Cr(VI) revealed a Cr deposit on the wall of the central cylinder and in the stele cells. Due to the morphological plasticity and tolerance demonstrated by T. domingensis, it can be concluded that it is a suitable species to be used in FTWs for the treatment of Cr-contaminated waters.
Emerging contaminants, including brominated flame retardants and microplastics, in agricultural soils pose a serious threat to crop security and ecosystem health. This study aimed to provide an understanding of the toxicity-induced effects of decabromodiphenyl ether (BDE-209) and polylactic acid (PLA) on Spinach (Spinacia oleracea) in the soil system by examining Spinach biomass, chlorophyll content, antioxidant enzyme activity, and microbial community composition after a 42-day exposure. The pre- and post-structural, morphological, and surface chemical group analyses of PLA and BDE-209 in contact with the soil system were analyzed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The data show that the combined treatment caused the most significant growth inhibition, with a 95% reduction in shoot dry weight and a 25% reduction in chlorophyll content, suggesting continued photosynthetic damage. Antioxidant enzyme analyses revealed an impaired defence system, wherein superoxide dismutase (SOD) activity increased (BDE-5: 48.4%, and BDE-6: 44.2%), whereas catalase (CAT) and peroxidase (POD) activities decreased (0.4-2.3%) across treatments, indicating metabolic blockage and subsequent hydrogen peroxide accumulation. The soil microbial composition in response to stress showed significant structural changes, including an increase in stress-tolerant genera, such as Bacillus (30-39%), and a decrease in beneficial Oligotrophic bacterial populations (58.9-74.0%). The degradation of PLA was confirmed by FTIR and SEM, which revealed surface interaction with BDE-209 and exhibited reduced absorbance between 1200 and 1000 cm-1, accompanied by a reduction in particle size (70-90 μm). These findings suggest that PLA may be a co-pollutant exacerbating BDE-209 toxicity by increasing oxidative stress and altering the soil microbial community.
2-Acetyl-6-methoxynaphthalene (2A6MN) is an important photoproduct of the non-steroidal anti-inflammatory drug naproxen (NPX) with high ecotoxicity. Herein, we determined the formation yields of 2A6MN from NPX transformation through various photoreaction pathways (including direct photolysis and reactions with hydroxyl radical (HO·), carbonate radical (CO3·-), and the triplet state of chromophoric dissolved organic matter (3CDOM*)), and identified the critical environmental factors affecting its formation through photochemical modeling. Results show that the primary photochemical pathways for the formation of 2A6MN included reactions with 3CDOM* (44.8%), CO3·- (41.3%), and direct photolysis (18.1%). Dissolved organic carbon (DOC) was the critical environmental factor influencing the formation of 2A6MN. However, water depth, nitrate (NO3-) and nitrite (NO2-) concentrations hardly affected the overall formation yields of 2A6MN. Results elucidate the characteristics of water bodies susceptible to the formation of ecotoxicologically relevant photoproduct, and permit a better assessment of the environmental risks and fate of NPX.
Pretilachlor herbicide is extensively used in rice cultivation. In open environment, it degrades into different metabolites. Information on the environmental mobility of these metabolites is limited. This study aimed to assess the potential movement risks associated with two principal metabolites of pretilachlor. To achieve the objectives, the sorption-desorption behaviour and the thermodynamic properties of pretilachlor (P), metabolite 2',6'-diethyl-N-(2-hydroxyethyl)aniline (M1) and 2-chloro-2',6'-diethylacetanilide (M2) were studied in different soils governing their mobility. Sorption kinetics followed a pseudo-second-order model (R2 > 0.98) across all the soils, while the equilibrium data fitted well to the Freundlich isotherm (R2 > 0.99). The sorption capacity decreased in the order P > M1 > M2, with Freundlich adsorption coefficients (KF-ads) ranging from 3.96 to 23.09 for P, 2.17-21.64 for M1 and 2.05-7.53 µg1-1/n g-1 mL1/n for M2. Sorption correlated positively with soil organic matter (OM) content; however, appreciable retention was also observed in soils with low OM (0.32%) where sorption coefficients (KD) ranged from 4.20 to 5.44 mL g-1 for P, 1.56 to 3.22 mL g-1 for M1 and 0.91 to 1.47 mL g-1 for M2. It highlighted about the contribution of clay and mineral fractions in addition to OM. PCA revealed two principal components, with PC1 (87.8%) and PC2 (9.2%) explaining 97.0% of the total variance, with the highest variation contributed by OM, clay and CEC. The optimum temperature for sorption was found to be 30 °C, beyond which a decline was observed. Desorption was low for P and moderate to high for M1 and M2 across different soils with hysteresis index (H) ranging from 0.003 to 0.758, indicating the partial irreversibility of the process. Thermodynamic analysis revealed that sorption was endothermic (ΔH = 1.64-7.49 kJ mol-1), spontaneous (ΔG = - 1.75 to - 7.90 kJ mol-1), entropy driven (ΔS = 0.05-0.30 J mol-1 K-1) and primarily physical in nature. Overall, this study revealed that P exhibited moderate sorption, whereas M1 and M2 showed low sorption and high desorption than P, indicating their greater mobility potential.
Organophosphate esters (OPEs) are ubiquitous in various environmental matrices due to their extensive use as flame retardants and plasticizers in our daily life. Triphenyl phosphate (TPHP) and tris(2-butoxyethyl) phosphate (TBOEP), two typical analogues of OPEs, pose risk to the environment, aquatic organisms and human health. In this study, Pelophylax nigromaculatus tadpoles were selected for a 21-day exposure experiment to determine the bioaccumulation and metabolic pathways of these two substances. The logarithmic concentrations (Log C) of TBOEP in tadpoles exhibited an increase over time, while those of TPHP demonstrated a slightly declining trend. TPHP displayed higher bioconcentration factors compared to TBOEP. Differences in bioaccumulation may be attributed to biotransformation and species variability. There were four TPHP metabolites (TP-251, TP-343a, TP-343b, TP-357) and TBOEP metabolites (TB-415a, TB-415b, TB-429a, TB-429b) identified in tadpoles while three TPHP metabolites (TP-343a, TP-343b, TP-343c) and TBOEP metabolites (TB-299, TB-415a, TB-415b) in water. Among these, TB-415b exhibited the higher potential for bioaccumulation. It can be inferred that TPHP and TBOEP underwent hydrolysis (yielding TP-251 and TB-299), hydroxylation (producing TP-343a/b/c, TB-415a/b and TB-429a), and methylation reactions (generating TP-357 and TB-429b). This study provides significant insights into the bioaccumulation and biotransformation mechanisms of TPHP and TBOEP within amphibians.
Fully understanding long-term liming effects on microbial dynamics requires further extensive and site-specific research. The study's core objective was to track how the amount of viable microbial biomass (measured via PLFA) and function (measured via enzyme activity) evolve in reclaimed Northern Ontario sites over time, providing insights into the process of ecosystem recovery. Four sites were selected, encompassing both limed areas and adjacent unlimed control areas. Although all sites were monitored concurrently, the applications of limestones occurred at different times. Liming at the freshly treated Kelly Lake site caused a temporary, significant increase in microbial biomass during the first four years of monitoring. This initial surge was absent in samples from older limed areas (Wahnapitae, Hwy 17 bypass, and Sudbury Snow Dump sites) monitored 7-13 years post-treatment, which suggests the effects had plateaued. Despite this short-lived microbial response, the overall positive effects of liming such as improved soil chemistry (e.g., increased pH and increased calcium) and enhanced plant population health seems to persist long after the initial biomass increase, demonstrating lasting ecological benefits. Variations in liming effects on soil biota were linked to differences in treatment duration and site-specific environmental characteristics. Microbial biomass values showed a strong positive correlation with pH (r = 0.76) and a weak positive correlation with organic matter (OM) values (r = 0.35). Amplicon sequencing analysis revealed a significant increase in bacterial community richness, indicated by significantly higher Chao1 values in limed (4450) versus unlimed (3446) soil samples, while fungal communities showed no such changes. Enzyme activities remained stable over time in both unlimed and limed samples, with two key exceptions among the C-cycling enzymes: beta-glucosidase (BG) and cellobiohydrolase (CBH). The activities of these two enzymes increased significantly over time in the limed soils. A consistent significant increase was observed for arylsulfatase (AS), an enzyme involved in S-cycling.
This study investigates the distribution, contamination status, possible sources, and health risks of heavy metals in urban road dust from Vadodara, a rapidly developing industrial city in western India. Vadodara was selected due to its increasing traffic density, mixed land-use pattern, and growing industrial activities, which may contribute to metal accumulation in roadside environments. Road dust samples were analyzed for chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn), cadmium (Cd), cobalt (Co), and copper (Cu) using microwave-assisted digestion followed by atomic absorption spectrophotometry. The mean concentrations of metals followed the order: Cr (32.87 mg/kg) > Mn (28.64 mg/kg) > Zn (7.78 mg/kg) > Ni (4.90 mg/kg) > Cu (3.85 mg/kg) > Pb (3.30 mg/kg) > Co (2.68 mg/kg) > Cd (0.40 mg/kg). Overall, metal levels were lower than those reported for highly industrialized cities, indicating moderate contamination in the study area. Contamination indices (CF, Igeo, and PLI) suggested generally low pollution, although Cd showed localized enrichment at specific high-traffic sites. Ecological risk assessment indicated low to moderate risk, mainly due to Cd. Human health risk assessment showed that ingestion is the main exposure pathway. Non-carcinogenic risk values (HI < 1) indicated no significant risk for both adults and children. However, carcinogenic risk values for children ranged from 1.59 × 10-4 to 5.63 × 10-4 at some locations, approaching or slightly exceeding recommended limits, mainly due to chromium and nickel. Source analysis indicated that traffic-related activities and resuspension of soil particles are the major contributors to metal accumulation. The findings highlight that, although overall contamination levels in Vadodara are not severe, localized hotspots and potential risks for children require attention. These results provide useful baseline data for urban environmental management and can support future monitoring and pollution control strategies in similar developing cities.
This study aimed to evaluate the accumulation of nickel (Ni) and cobalt (Co) and their associated human health risks in two guava varieties (Gola and Surahi) grown under contrasting irrigation systems. For the analysis of Ni and Co, samples of water, soil, and fruits were collected from peri-urban areas, Chak 81 S.B (Site I) and 88 S.B (Site II) of Sargodha, Pakistan, which were irrigated with tube well water and wastewater, respectively. The mean values of Ni and Co were found in the range of 0.043 to 0.217 and 0.017 to 0.040 mg/L in water, 1.070 to 1.254 and 1.032 to 1.248 mg/kg in soil, and 0.281 to 0.582 and 0.202 to 0.252 mg/kg in fruit samples, respectively. The health risk assessment revealed that only Ni exceeded the safety threshold (maximum HRI = 1.113), indicating a potential health concern associated with the consumption of wastewater-irrigated guava, whereas all Co HRI values remained below 1 and did not indicate a significant health risk. These findings suggest that prolonged use of wastewater for irrigation should be carefully monitored and managed to minimize potential health risks associated with nickel accumulation in the food chain.
In Europe, agriculture has been seriously affected by the increased frequency of droughts. Agricultural fields are also exposed to traffic-related air pollution. Air pollution and drought elucidate simultaneous stress, which has been scarcely studied. The major objective of the study was to evaluate the combined effects of air pollution and drought stress on different tomato varieties/landraces. 3 commercial varieties as well as 2 Hungarian landraces were selected, effects of the combined stressors were evaluated based on biomass reduction and biochemical end-points such as photosynthetic pigments concentrations and peroxidase (POD) activity. Air pollution was simulated by treating test plants according to the No. 227 OECD Guideline. Differences were experienced in the sensitivity of varieties, landraces tested: the regional landrace 'Tápiószelei' proved the most tolerant to any combination of treatments. Results stress the importance of the cultivation of regional landraces to cope with environmental stress in a changing climate.
The isolated evaluation of physicochemical parameters of effluents in landfill leachate treatment is insufficient to determine reductions in acute or chronic toxicity to aquatic biota. Therefore, ecotoxicity tests are essential to assess environmental contamination. This study evaluated the ecotoxicological impacts, through acute and chronic tests on different organisms, of raw landfill leachate, leachate treated with ammonia stripping and activated sludge, and leachate post-treated by coagulation-flocculation-sedimentation (CFS) and adsorption using powdered activated carbon (PAC). Tests with P. subcapitata, C. dubia, D. magna, and A. salina indicated that biologically treated leachate exhibited lower toxicity than raw leachate. However, during post-treatment with CFS combined with PAC adsorption, despite the significant removal of recalcitrant compounds, toxicity increased for P. subcapitata, C. dubia, and D. magna, likely due to residual metals and chlorides from the coagulant and acidifier. Among the tested organisms, A. salina exhibited responses that differed from those of the other species, with a gradual decrease in toxicity observed after each treatment stage. This behavior may be partially associated with its marine origin and potential tolerance to chlorides.