Environmental Geochemistry and Health最新文献

PM_2.5 in the air can adsorb a wide range of substances, and due to their small size, they can carry toxic and hazardous substances into the human body through inhalation, which can be harmful to human health. PM_2.5 samples were collected in Shihezi for one year from September 2021 to August 2022 to characterise the distribution of 13 metallic elements in PM_2.5 and their potential sources. The findings revealed that the concentrations of PM_2.5 surpassed the national threshold of 35 μg/m³, alongside elevated levels of crustal elements. To assess the potential sources of the 13 metallic elements, present in PM_2.5, a comprehensive analysis was conducted utilizing Enrichment Factor analysis, principal component analysis (PCA), and Backward Trajectory Modelling. The Enrichment Factors analysis revealed that five elements were significantly influenced by anthropogenic activities, with cadmium exhibiting particularly high levels of enrichment. PCA indicated that the metal elements were predominantly sourced from coal combustion, vehicular emissions, dust, fossil fuel combustion and industrial activities. Backward trajectory cluster analysis demonstrated that pollutant concentrations are substantially affected by both long-range transport mechanisms and localized anthropogenic sources. The assessment of health risks associated with metallic elements suggests a low risk to human health. These findings offer a crucial scientific foundation for air pollution management strategies in the SHZ region.

Microplastics (MPs) are widespread environmental pollutants. This study primarily examines the changes in electro distribution of aged MPs in aquatic environments and their subsequent impact on the environment. Under the action of natural and artificial aging, the electron cloud arrangement of MPs will change, thus affecting the relevant properties of MPs. Among them, the free radicals formed by advanced oxidation technology will be enriched on the surface of MPs carrying benzene rings, and react with other pollutants (organic pollutants, heavy metals, etc.) adsorbed by MPs to form environmental persistent free radicals (EPFRs). The electron cloud density of MPs carrying EPFRs increases, and the reactivity will also increase. Additionally, the oxygen-containing functional groups on the surface of aged MPs enhance their selective adsorption, altering their environmental impact. MPs can serve as a source of free radicals in the environment, enhance the oxidation capacity of other substances in the environment, and even affect the expression of antibiotic resistance genes. In addition, MPs have a high mobility, which will have a greater negative impact in the environment. Additionally, the high mobility of MPs amplifies their negative environmental impact. This study examines the changes in electron distribution of aged MPs and highlights their effects on aquatic ecosystems, providing insights into pollution control, toxicity, and degradation mechanisms.

The phase transformation of Schwertmannite (SCH) can significantly affect the interface behavior and toxic effect of As(III). Previous studies have predominantly focused on pollutants adsorption by SCH on a long-time scale (such as 30 days), without paying attention to the adsorption characteristics within shorter time frames (e.g., within 24 h). This work compared the adsorption characteristics of As(III) on three synthesized SCHs under various environmental conditions. The adsorption of As(III) by M-SCH (SCH synthesized by KMnO₄ oxidation method) and Y-SCH (SCH synthesized by ethanol modification method) were governed by physical adsorption, while that of H-SCH (SCH synthesized by H₂O₂ oxidation method) was dominated by chemisorption. Acidity, selected ions (NO₃^-, Ca²⁺, CO₃^2-, and PO₄^3-), fulvic acid (FA), and Sb(III) adversely impacted the As(III) adsorption by SCHs. Furthermore, alkalinity, selected ions and FA induced the phase transformation of SCHs to iron hydroxide, while no transformation was observed in the presence of Sb(III) and Cr(VI). The iron hydroxide observed in this study is presumed to represent an intermediate stage in the transformation of SCH into goethite. These findings enhance our comprehension of the transformation process of SCH to goethite and provide scientific insights for SCH utilization in immobilizing As(III) in water.

Geochemical analysis of Potentially Toxic Elements (PTEs) in stream sediments is essential for understanding environmental impacts in areas with complex geology and mining activities. This study focuses on stream sediments from the eastern sector of the Mt. Amiata Hg-district (central Italy) to define the background values of As, Sb, Cr, V, Co, Cu, Ni, and Hg, the latter being speciated to assess its bioavailability and mobility for potential environmental risks. The stream sediments are divided into four different groups: (1) Volcanic, (2) Volcanic-dominated, (3) Sedimentary-dominated, and (4) Sedimentary. This subdivision is confirmed by spatial distribution maps. While Cr, Co, V, Cu, and Ni are related to mafic and ultramafic rocks, Hg shows higher concentrations (up to 850 mg/kg) close to the former mining sites and organic-rich areas. In streams draining the Mt. Amiata volcanics and hydrothermal zones, As is up to 311 mg/kg while Sb is uniformly distributed (up to 84 mg/kg), though depleted in volcanic rocks. Consolidated sediment clusters (group 1 and group 2 and group 3 and group 4, respectively) are used to calculate the geochemical background values (crucial for post-extractive land reclamation), which result to overcome the concentrations imposed by the Italian law for Hg in both clusters, As in cluster 1 and Co in cluster 2 (5.2-6.3, 20-24.3, 39.7-48.5, and 26.3-32.2 mg/kg, respectively). In the stream sediments, Hg speciation by thermal desorption highlights the presence of stable Hg forms. Thus, low Hg bioavailability is expected, being also consistent with the soils from the nearby mining areas.

In view of the rainwater pollution problems in highway runoff on the Northwest Expressway, especially heavy metal pollution and poor soil water retention, this study focused on the sandy soils along the highway sides in Qilian Mountain National Park, Gansu Province. It investigated the removal of pollutants as well as water and fertilizer retention effects in simulated highway rainwater runoff using four amendments: carboxymethyl cellulose (CMC), corn straw biochar, corn cob biochar, and rice husk biochar, both individually and in combination. Through permeability tests, evaporation tests, and static adsorption experiments, the optimal soil treatment for runoff rainwater was determined. Experiments showed that mixing soil with quartz sand in a 4:6 ratio and adding 5% rice husk biochar and 0.1% CMC can significantly enhance the adsorption of various pollutants and improve soil moisture retention. We packed the initially selected improved soil matrix into columns, initiated operation, and set the influent flow rate to 9 mL/min. During stable operation, the average retention rates of nutrients-ammonia nitrogen (NH₄⁺-N), total phosphorus, and chemical oxygen demand-from highway runoff were 81.75%, 66.72%, and 77.97%, while the average removal rates of copper (II) (Cu²⁺) and chromium (VI) (Cr⁶⁺) were 91.94% and 84.18%, respectively. After operation, the residual forms of copper (Cu) and chromium (Cr) in the soil matrix accounted for 56.96% and 52.28%. The transformation of Cu and Cr into stable residual forms with low migration risk effectively reduced their environmental impact.

Carbon- and sulfur-bearing gases are emitted at relevant amounts from hydrothermal manifestations at Tivoli Terme (Latium, central Italy), where different potential anthropogenic contaminant sources also occur. This study presents a geochemical dataset including CO₂, CH₄, SO_2, and H₂S concentrations and δ¹³C-CO₂ and δ¹³C-CH₄ values measured in air at the center of Tivoli town. The main aim was to evaluate the impact on air quality of hydrothermal manifestations and anthropogenic activities employing a traditional stationary monitoring strategy. The analytical results reveal significant air contamination from both natural and anthropogenic emissions, although gas levels were below outdoor air quality thresholds. Carbon dioxide and CH₄ were primarily linked to anthropogenic sources, while hydrothermal emissions played a secondary role. However, H₂S concentrations up to 282 ppb highlighted a notable impact from hydrothermal emissions surrounding the measurement station, where SO₄-rich pools are located. Nevertheless, the geochemical data did not provide a reliable estimate of the specific contributions from each source. The study identifies key limitations in relying on a single fixed monitoring station, as weather conditions highly influence it and cannot reliably capture the relative impacts of various sources across a broad area. Additionally, compositional and isotopic geochemical parameters often produce ambiguous results, complicating the differentiation of pollution sources. An integrated approach is recommended, combining mobile stations for periodic pollutant mapping with low-cost instruments deployed at strategic locations near potential sources and progressively farther away. This strategy could better track the spatial and temporal evolution of contaminant concentrations, addressing the shortcomings of current monitoring systems and enhancing mitigation efforts.

The main objective of this study is to predict and monitor groundwater quality through the use of modern Machine Learning (ML) techniques. By employing ML techniques, the research effectively evaluates groundwater quality to forecast its future trends. Five machine learning models Logistic Regression (LR), Support Vector Machine (SVM), Random Forest (RF), Adaptive Boosting (AdaBoost), Extreme Gradient and Boosting (XGBoost) were used here to predict the water quality by assessing the physical and chemical parameters such as electrical conductivity (EC), hydrogen ion (pH) concentration, total dissolved solids (TDS), chemical parameters such as, sodium (Na⁺), magnesium (Mg²⁺), calcium (Ca²⁺), potassium (K⁺), bicarbonates (HCO₃^-), fluoride (F^-), sulphate (SO₄^2-), chloride (Cl^-), and nitrate (NO₃^-) in 94 dug and bore wells from the semi-arid river basin (Arjunanadi) in Tamil Nadu, India. The pH of the samples is alkaline nature. Gibb's diagram suggested the rock-water dominance and minor influence of evaporation and crystallization on the hydrochemistry. From water quality index, 599.75 km² (53%) of area has a good quality and 536.75 km² (47%) of area has poor water quality. Water Quality Index values (WQI) of water quality formed baseline data for the prediction models as a dependent variable, and the physicochemical parameters were used as independent variables. The model efficacies were assessed using statistical error such as Relative Squared Residual (RSR) error, Nash-Sutcliffe efficiency (NSE), Mean Absolute Percentage Error (MAPE), Coefficient of determination (R²) and final accuracy. In this study, the LR model provided the minimal error (RSR = 0.22, NSE = 0.95, MAPE = 1.3) with an accuracy of 95% in predicting the water quality. The performance of the ML models is in the sequence of SVM > Adaboost > XGBoost > RF. This study helps the lawmakers and administrators for creating awareness on modern techniques for predicting and monitoring groundwater quality on the general public and supporting to achieve the sustainable development goals 3 and 6 for clean and healthy community.

The mass production and applications of tripropyl phosphate (TPrP) and tributyl phosphate (TBP) have facilitated their widespread distribution in aquatic environments, thereby posing a threat to the ecosystem. Here, the acute toxicity of TPrP and TBP to Microcystis aeruginosa and the underlying mechanisms were investigated. The results demonstrate that both TPrP and TBP can significantly inhibit the growth and reduce cell viability of M. aeruginosa with increasing concentrations and exposure time. Moreover, the treatment with TPrP and TBP result in a notable reduction in the content of chlorophyll a. The content of dissolved organic carbon (DOC) is down-regulated at lower concentrations, and shows a gradual increase with increasing concentrations of TPrP or TBP. Meanwhile, minor discrepancies have been observed in the proportions of DOC components through excitation-emission-matrix (EEM) spectra. The exposure of TPrP and TBP results in the production of excessive reactive oxygen species (ROS) and the increase of antioxidant enzymatic activities, including superoxide dismutase (SOD) and catalase (CAT). TPrP, but not TBP, has been demonstrated to enhance the MDA level, indicating a significant effect on membrane lipid peroxidation. The differences in the respective toxicity mechanisms and biological effects can be attributed to the alkyl chain lengths and physicochemical properties inherent to each compound. Consequently, the study not only offers insights into the acute effects of the two alkyl organophosphate esters on M. aeruginosa, but also provides a scientific basis and framework for assessing their ecological risk in aquatic environments.

Despite global efforts, air pollution continues to be a ubiquitous public health problem, especially in urban environments. Consequently, for the highly urbanized societies like the state of Kuwait, there is an urgent need to identify high-risk areas in order to reduce the risks of exposure to harmful pollutants. Soil and dust particles were collected from 4 different locations under various land use practices and societal activities to assess the potential for health risks posed to Kuwait City residents. Selected potentially toxic elements (PTEs), some of which are given in the United States Environmental Protection Agency (USEPA) priority pollutants, were analyzed for contamination factor (CF), ecological risk (ER), and human health assessment (HHA). The CF of metals followed the decreasing order of Co > Cd > As > Ni > Fe > Cr > Ba > Pb. The CF and potential ecological risk index (PERI) were found to be the highest in the road dust collected at the Shuwaikh industrial location. The hazard quotient (HQ) for Arsenic (As) was greater than 1 at all locations. Although carcinogenic risk assessment (CRA) ratios were below the standard limit of 1 × 10^-4 for both children and adults, the ratios were greater for children. The detection of carcinogenic metals such as As, Cd, and Co at pollution degrees > 6 causes concerns about potential health risks, especially during developmental growth stages. This research underscores the urgent need for effective urban planning and pollution control measures by addressing the sources and pathways of road dust and soil particles to better protect public health and improve the quality of life in urban environments. In urban environment, there are diverse sources of pollution and pathways, making it challenging to isolate the relative contribution of road dust and soil particles, requiring further research.

The groundwater salinization problem in the south bank of the Yellow River irrigation area is severe, restricting the sustainability of groundwater resources. However, the groundwater salinization formation mechanism is unclear. Accordingly, this study analyzed the chemical characteristics and salinization mechanism of groundwater based on hydrochemical analyses (self-organizing maps, SOM), isotope analyses (δ¹⁸O and δD), and quantitative models (Rayleigh distillation model), as well as evaluating the potential health risks of fluoride. The results indicated that surface water and groundwater in the study area had high salinity and weak alkalinity, with the fluoride and total nitrogen (TN) content exceeding Grade III water standards. Additionally, only 42% of the water samples were suitable for drinking, with nitrogen sources being the main cause of water quality deterioration. Around half of the samples were unsuitable for irrigation. The spatial and temporal distribution of total dissolved solids (TDS) in the irrigation area was influenced by autumn irrigation. Overall, groundwater salinization was primarily attributed to evaporite dissolution, cation exchange, silicate weathering, and human inputs. Evaporation was not the main influencing factor. In addition, the non-carcinogenic risk of fluoride in the water body decreased as follows: infants > children > adult females > adult males. The results of this study deepen understanding of the relationship between changes in groundwater quality and the ecological environment in semi-arid inland areas, thereby promoting the rational utilization and scientific management of groundwater resources in the irrigation area.