Search

Environmental context Biochar produced by agricultural wastes can be used for vanadium treatment, soil fertility improvement, and agricultural waste disposal, whereas acid rain leaching may decrease its remediating efficiency of the metal contaminated soil. Therefore, vanadium behaviour in soil and soil quality change after biochar application were analysed under simulated acid rain leaching. Findings provide insights into acid rain leaching effects on soil quality, vanadium release from soil, and biochar remediating efficiency. Rationale Considering the effects of acid rain on the leaching of metals and nutrients in soil, rice straw biochar, with the potential to remediate and improve the quality of vanadium contaminated soil, was further evaluated for its remediating and ameliorating performance of soil under acid rain. Methodology The adsorption capacity and isotherm of vanadium by rice straw biochar were investigated. Simulated acid rain leaching experiments were performed to study the influence of acid rain on vanadium behaviour in soil and nutrients and on the structure of the soil. Results Isotherm adsorption studies indicated a preference for a monolayer process without transmigrations of the adsorbed vanadium onto the biochar surface. After leaching with simulated acid rain, compared with the untreated soil, the available vanadium (129.63 ± 3.75–76.10 ± 3.24 mg kg−1) in the soil decreased notably by adding 2–3 wt% biochar (P

Sufficient attention should be attached to the large amount of fly ash containing high levels of toxic heavy metals generated after municipal solid waste incineration. Because heavy metals could be leached out of the fly ash under specific conditions, it is necessary to stabilize the heavy metals in fly ash before landfill disposal. Processing technologies of incineration fly ash include solidification/stabilization technology, thermal treatments, and separation processes. This study reviewed the current treatment technologies of municipal solid waste incineration (MSWI) fly ash, with the main focus on the treatment of heavy metals in fly ash with chemical stabilization. Chemical stabilization processes involve chemical precipitation of heavy metal and chelation of heavy metals. In multiple studies, chemical stabilization technology has shown practical feasibility in terms of technology, economy, and effect. In addition, the combination of two or more stabilization agents broadens the general applicability of the agents to heavy metals and reduces the cost. The application of joint processing technology realizes the remove of soluble salt from fly ash. To minimize pollutants while increase their usable value, effective use of waste and co-disposal of several kinds of wastes have gradually become the research hotspots. New developments in chemical stabilization are progressively moving towards the sustainable direction of harmlessness and resource utilization of MSWI fly ash.

Microplastics (MPs), polymer particles capable of accumulating heavy metals from ambient medias, have been widely found in agriculture and pasture soils. Through the consumption of MPs in soils, heavy metals adsorbed on MPs can be transported into ruminant digestive guts. To explore the behavior of Cd loaded MPs in ruminant digestive system, we initially established a ruminant digestive in-vitro method (RDM) that simulates the rumination cycle between mouth and rumen to evaluate the release rates of Cd on 4 most commonly used undegradable MPs (PE, PP, PVC, and PS) and a biodegradable MP (PLA). After 120 h of adsorption, the Cd adsorption capabilities by 5 MPs ranged from 0.23 μg/g to 2.45 μg/g. Through RDM, all tested Cd loaded MPs released high proportions of Cd with release rates from 21.5% to 41.8%, where PLA showed the highest Cd release rate. Cadmium was mainly released in rumen and abomasum phases, and the rumination cycle between mouth and rumen can affect the Cd release from MPs. The present study provides a new view on the environmental hazard of heavy metal and MP pollution that their co-exposure to ruminants should be taken into account.

Elevated vanadium in the environment adversely affects organisms, including plants, animals, and humans. Plants act as the main conduit for environmental vanadium to enter the food chain, and simultaneously their growth response characteristics reflect vanadium toxicity efficacy for plants. The aim of the present study is to investigate lettuce (Lactuca sativa L.) growth involving morphological change, physiological adjustment, vanadium accumulation under vanadium stress, and the potential health risk (expressed as health risk index (HRI)) of adults and children who consume it. Lettuce was grown in nutrient solution with 0, 0.1, 0.5, 2.0, and 4.0 mg L-1 of pentavalent vanadium [V(V)]. Results showed that 0.1 mg L-1 V did not significantly affect lettuce growth versus control, and marked depression arose at ≥ 0.5 mg L-1 V. Foliar proline increased rapidly at ≥ 0.5 mg L-1 V. No striking change emerged in leaf cell membrane permeability at all treatments. V(V) and total vanadium concentration in plant tissues were ordered as root > stem > leaf, while tetravalent vanadium [V(IV)] was leaf > root > stem. No health risk (HRI < 1) exists for adults and children who consume lettuce at control treatment. However, the health risk occurs (HRI ˃ 1) when they both ingest the seedlings exposed to ≥ 0.1 mg L-1 V, and the risk overall markedly increases with increasing vanadium. Therefore, enough attention needs to be paid to the human health associated with the ingestion of vegetables like lettuce grown in substrata contaminated by vanadium.

Pot experiments with alfalfa, milkvetch root and swamp morning glory were conducted to elucidate the effect of soil vanadium (V) on plant growth and to evaluate their phytoremediation potential under V(V) exposure. Based on biomass analysis, swamp morning glory showed higher tolerance than alfalfa and milkvetch root in response to different soil V(V) levels. The accumulation of V in plants increased with the increasing soil V and the V concentration in roots was 1.95-4.31 times that in shoots. After planting, soil total V, V(V), bioavailable V and water-soluble V all reduced, and the decreases in bioavailable V and V(V) showed significant. The decreased percentage of V(V) in total V in soils demonstrated that the planting process may stimulate the mechanism of V(V) reduction to V(IV). Therefore, the three tested plants, particularly swamp morning glory can be promising phytostabilizers applied to V phytoremediation practices.

To evaluate the impact of F in soil on seed germination, growth performance and biochemical parameters of Chinese cabbage (Brassica campestris L.) and oilseed rape (Brassica napus L.), a pot experi...

The widespread use of plastic film in agricultural production has resulted in the accumulation of large amounts of residual plastic film in the soil, and most of the plastic residuals eventually break up into microplastics (MPs). However, the effects of different film mulching methods on the soil ecosystems are largely unexplored. Therefore, we investigated the MPs distribution and the physicochemical properties and microbial community structure in the farmland soil tillage layer covered with different mulching method of film. The results indicate that the film mulching method had no significant effect on the soil pH and organic matter content, however, the respiration intensity of the soil covered with mulching film (MF) (60.11-84.99 μg/g) and shed film (SF) (56.10-65.68 μg/g) was significantly higher than that covered with shed filmmulching film (SMF) (17.25-39.16 μg/g). The MPs abundance in the soil covered with MF (1367 particles/kg soil) was significantly higher than that covered with SF (800 particles/kg soil) and slightly higher than that with SMF (1000 particles/kg soil). The small-sized (0-0.5 mm) MPs abundance was increased with the tillage layer depth (0-20 cm), while the large-sized (1-5 mm) MPs abundance was the opposite. In addition, in the soil covered with agricultural film, the dominant phylum and genera of the bacteria were Proteobacteria (relative abundance was 64.06 %) and Pseudomonas (13.16 %), respectively. In the soil without agricultural film application as a control treatment, the diversity of the soil bacterial community was higher than that in the soil covered with agricultural film, and the relative abundances of the top 10 genera were all less than 5 %. Overall, this study provides essential information for understanding the effects of different film mulching methods on the agricultural systems. Overall, this study provides essential information for understanding the effects of different film mulching methods on the distribution of MPs and the biogeochemical properties of farmland soils.

Seed germination is the critical initial phase in the life cycle of plant and it is affected by various exogenous factors, including heavy metals. Seed germination and subsequent seedling growth of alfalfa (Medicago sativa L.) incubated in glass Petri dish in presence of elevated concentrations of pentavalent vanadium V(V) solution (0, 0.1, 0.5, 2, 4, 10, 50 mg L−1 V, supplied as NaVO3·2H2O) were evaluated. Results showed that vanadium did not (P > 0.05) affect seed germination, final survival rate, and seedling height of alfalfa when exogenously treated dosages were ≤ 10 mg L−1 V, whereas the root vitality and root elongation were distinctly inhibited at ≥ 0.5 mg L−1 V treatments. A progressively deepened testa color at increasing vanadium concentrations during germination and an apparent modified structure of the seed coat at 50 mg L−1 V compared to control in alfalfa were noted. Alfalfa seeds showed rapid and almost synchronous radicle emergence, independently of the vanadium concentration in the medium. The accumulation of vanadium in testa is beneficial to alleviate its toxicity to the seed germination of alfalfa. Leaf proline content was dramatically increased at ≥ 0.5 mg L−1 V treatments compared with the control. Emerged seedlings displayed enough vigor and health to potentially colonize in the vanadium-contained matrix. Thus, alfalfa represents a good candidate for phytoremediation approach aimed at decontaminating environments when vanadium concentrations are within the determined thresholds.

Vanadium (V) pollution in soil has been widely noted, while knowledge about the effect of soil colloid on migration of V is scarce. Batch adsorption-desorption and transportation of the colloid-adsorbed V in columns packed with quartz sand under various environment conditions were carried out to explore the retention and transportation of V by colloidal kaolinite. Batch adsorption-desorption studies show that the adsorption of V by the colloidal kaolinite was mainly specific adsorption and redox played a limited role in the adsorption process. The maximum adsorption capacity of the colloidal kaolinite was 712.4 mg g−1, and about 5.9–8.7% of the adsorbed V could be desorbed. Both the adsorption-desorption and migration of V with colloidal kaolinite were highly ambient condition dependent. The column studies show that V was highly mobile in the saturated porous media. An easier transfer of V with an increase in pH, IS, and velocity of flow was noted. However, the increase of IS lead to the blockage of the colloidal kaolinite transportation. The recovery rate of the colloidal kaolinite at pH 7 and 9 was 2.0 and 2.1 times that at pH 5, respectively. The migration of colloidal-adsorbed V in sand column preceded that of V ion, but more colloidal-bound V than V ion remained in the column. Lack of consideration of the combination and co-transportation of V and colloidal kaolinite will lead to an overestimation of the risk of V to deeper soil profiles and groundwater.

Combining biodegradable chelating agents with phytoextraction is an efficient technique to amend metal-contaminated soils, but most studies have addressed remediation efficiency rather than a comprehensive understanding of the interactions among plant stress, metal accumulation, and metal bioavailability. This study aimed to investigate the effects of biodegradable chelating agents on improving the efficiency of phytoextraction for cobalt (Co)-contaminated soil by sweet alyssum (Lobularia maritima (L.)) and to explore the interrelationships among plant stress, Co accumulation, and Co bioavailability. Sweet alyssum (three plants per pot) was grown in pots containing soil with Co added at 0, 40, and 60 mg kg−1, respectively. After 70 days of growth, we added four biodegradable chelating agents (EDDS, NTA, CA, and OA) at various concentrations (0, 2.5, 5.0, and 7.5 mmol kg−1). The plants were harvested after 7 days, and the biomass, reactive oxygen species (ROS) parameters, Co concentrations of the shoot and root, and available Co content in the soil were analyzed. The results demonstrate that chelating agents significantly (p

Vanadium (V) is a toxic metal, which dominantly exists as V5+ in an aquatic environment. Rice straw, which is an abundant agricultural by-product throughout China was used to treat V5+ containing w...

The stockpiling of vanadium-containing tailings allows vanadium to migrate into the surrounding area, resulting in toxic metal contamination. By using the vanadium-bearing iron/manganese (Fe/Mn) oxide agglomerates as the simulated tailings, the feasibility of photo-induced reduction of vanadium by oxalic acid was investigated. Batch effects of the available light and the reducing agents on agglomerates were investigated. Results showed that oxalic acid (5 mmol L

Vanadium (V) is a widely distributed and potentially dangerous pollutant in soils. However, the extraction methods for bioavailability of V in soils have not been unified. This study focused on the...

Vanadium (V) contamination in soil can cause diverse damage to soil ecosystem and has attracted research interests in exploring soil V stabilization methods, but only a few materials were proposed and studied. Here, a pot experiment was firstly conducted to estimate the efficiency of nano-hydroxyapatite (n-HAP) in stabilizing V in soil. To verify the impact of n-HAP on soil V bioavailability and phytotoxicity, cabbages (Brassica chinensis L.) were grown in V-spiked soils after n-HAP amendment. Soils were sampled from a farmland in China, and the n-HAP was prepared in the laboratory. In each pot of soil spiked with 0, 75, 150, 300, and 600 mg/kg V, 2% n-HAP was amended for 30 days, while soils without n-HAP amendment were set as controls. The stabilization effect of n-HAP on V in soil was estimated by the water-extractable and bioavailable V concentrations in soils. Cabbages were grown in pots subsequently. The V(V/IV) concentrations in cabbage leaves and roots, the organic bound V concentrations in cabbage roots, and the chlorophyll concentrations in leaves were determined. Bioconcentration factor and translocation factor were calculated. The composition of organic bound V in leaf was characterized by fluorescence excitation–emission matrix. In soils spiked with 150 mg/kg V, n-HAP amendment yielded the highest stabilization rates of 51.0% and 42.4% for water-extractable and bioavailable V, respectively. In 75, 150, and 300 mg/kg V-spiked soil, the plant weight, plant height, and root length of cabbage after 60-day growing decreased 54.6%/89.6%, 30.9%/45.5%, and 41.5%/51.4% in groups with/without n-HAP, respectively. Cabbage leaf chlorophyll concentrations descend firstly then ascend with rising soil V concentration. Leaf V speciation analysis revealed that less leaf V was reduced to V(IV) in groups amended with n-HAP than groups without n-HAP amendment. In 150 and 300 mg/kg V-spiked soil, n-HAP effectively reduced the V content and the V bioconcentration factor of cabbage root. Tyrosine-like and humic acid-like analogues composed the principal part of V complex. In general, n-HAP amendments are potential to decrease the mobility of V in soils, as well as inhibit the bioavailability and phytotoxicity of V to cabbage. In V-spiked soils, n-HAP amendment can alleviate the toxicity of V to the cabbage. Overall, 2% n-HAP is efficient for the amendment of slight V-polluted (150–300 mg/kg) soils to alleviate the soil V stress to cabbage.

Chromium (Cr) pollution is the primary pollution problem of the soil in tannery. However, the effect of tanning chemicals on Cr migration in soil has not been clearly elucidated. Column leaching tests were designed in this study to reveal the transport and transformation of Cr from basic chromium sulfate (BCS) into soil and the effects of lime on Cr migration and transformation. The results showed that BCS was mainly leached out in the state of Cr(VI) after entering the soil, and the Cr concentration in leachate decreased with the increase of the bulking thickness of the BCS. Compared with the soil absent of lime, the concentration of total Cr in the leachate from soil with lime decreased by 8.80-88.1%. The proportions of Cr in the residual fraction were generally increased in the soil with lime, whereas other fractions were decreased. The presence of lime can reduce the migration and toxicity of BCS in soil to a certain extent. The analysis of soil bacterial community showed that the relative abundance of Proteobacteria increased significantly with the exposure to BCS and the Burkholderiaceae was the dominant bacteria family in the BCS contaminated soil. Understanding the mobility of BCS and lime and the bacterial community in BCS contaminated soil is conducive to the risk assessment of the tannery site.

Vanadium-titanium (V-Ti) magnetite tailings have caused great concern due to their safety hazards and environmental risks. However, the microbial community structure and the key geochemical factors of V-Ti magnetite tailing profiles under different management modes remain unclear. Therefore, we investigated the heavy metal distribution and the microbial community structure of the soils and tailings at varied depths of V-Ti magnetite tailing profiles with and without soil coverage. The results indicated that the topsoil covering measures retarded the acidification of tailings during stockpiling. However, As, Mn, and V in tailings have the ability to migrate to the overlying soil. Based on 16S rRNA gene amplicon sequencing, Proteobacteria was the dominant genus in the topsoil-covered tailings, whereas the most abundant genus in the exposed tailings was Betaproteobacteria. Furthermore, Rhodobacter, Hydrogenophaga, Novosphingobium, and Geobacter enriched in tailings may potentially contribute to V(V) biotransformation and the development of mine bioreremediation technologies. RDA and Spearman correlation analysis showed that pH, EC, Cd, Mn, Pb, and V were the main influencing factors regulating microbial community composition. Overall, this study provides insights for evaluating the soil covering management mode and the engineering applications of microbial technologies to manage V-Ti magnetite tailings.

The widespread usage of per- and poly-fluoroalkyl substances (PFAS) has caused great concern due to their potential toxicology to human and environmental health. However, there have been limited investigations on the vertical distribution of PFAS in fluorine (F) contaminated soils. In this study, the spatial and vertical distribution of metals, total F, and PFAS in the soil profiles were investigated at different areas in an industrial city. The higher F concentrations in the farmland soils with intensive agricultural activities suggested the impacts of soil tillage. The ΣPFAS concentrations ranged from 0.187 to 1.852 ng g

Long non-coding RNA (lncRNA) is a class of non-coding RNAs with a length greater than 200 nucleotides. Although lncRNAs do not have any protein coding capability, they can affect the phenotypes of traits by influencing gene expression through transcriptional regulation, post-transcriptional regulation, and epigenetic modification. In modern animal husbandry production, besides increasing growth and yield traits, investigations on the regulation mechanisms of immune factors, cytokines and other disease resistance-related indicators and traits are particularly important for improving the health and welfare of domesticated animals as well as public health. In recent years, researchers have made significant progress in understanding the regulatory mechanisms of lncRNA on the disease resistance traits of chickens (Gallus gallus), pigs (Sus scrofa), cattle (Bos taurus) and other important domesticated animals, thereby laying the basic foundation for the translational application of epigenetic markers in breeding of animals with disease resistance. In this review, we briefly introduce the biological functions and the origins of lncRNAs, then focus on the research progress on the regulatory effects of lncRNAs on disease resistance traits of domesticated animals, and thus providing the scientific basis for the research of lncRNA and its application in the breeding of disease-resistant animals.长链非编码RNA (long non-coding RNA, lncRNA)是一类长度大于200个核苷酸的非编码RNA分子。lncRNA虽然不具备蛋白编码能力,但可通过转录调控、转录后调控及表观遗传修饰调控等方式影响基因的表达,进而影响性状的表型。在现代畜牧业生产中,除提高生长发育和产量性状外,研究免疫因子、细胞因子等抗病力相关指标及性状的调控机制,对提高和改善畜禽的健康、福利及公共卫生尤为重要。近年来,利用lncRNA研究鸡(Gallus gallus)、猪(Sus scrofa)、牛(Bos taurus)等重要畜禽的抗病力性状的调控机制取得了一定进展,为将表观遗传标记应用于动物抗病遗传育种打下了一定的基础。本文介绍了lncRNA的生物学功能和产生机制,着重阐述了lncRNA对畜禽抗病力性状的调控作用及研究进展,以期为lncRNA在畜禽抗病遗传育种方面的研究及应用提供科学依据。.

Although patients with rosacea often consult dermatologists for dietary factors that might be related to their skin disorders, few studies have been conducted to research the relationship between rosacea and dietary factors. The purpose of this study was to evaluate the potential relationship between rosacea and diet among the large Chinese population with rosacea, which would provide dietary guidelines for patients with rosacea. A multicenter case-control study was conducted. The feeding frequency 2 years before the occurrence of rosacea was collected by standardized questionnaires. Multiple logistic regression analysis was used to calculate risks related to the diet. One thousand three hundred and forty-seven patients with rosacea and 1290 controls were enrolled in our study. We found that high-frequency intake of fatty food and tea presented a positive correlation with rosacea, while high-frequency dairy product intake showed significant negative correlation with rosacea. Sweet food, coffee and spicy food appeared to be independent of any subset of rosacea in our study. However, high-frequency dairy product intake showed a borderline beneficial effect on rosacea severity. We further analyzed the correlation between diet and the subtype of rosacea. We found that high-frequency fatty intake was associated with erythematotelangiectatic rosacea (ETR) and phymatous rosacea, while high-frequency tea intake was only associated with ETR. In addition, high-frequency dairy product intake showed negative correlations with ETR and papulopustular rosacea. Rosacea is associated with some dietary factors, and our study is valuable in establishing dietary guidelines to prevent and improve rosacea.

Oral bioaccessibility of vanadium(IV) and vanadium(V) in soil, dust and concentrate fines from a vanadium titanomagnetite mining region was assessed by a whole digestive system in-vitro scheme. The scheme including the addition of sweat and the large intestinal digestion was used to estimate the oral bioaccessibility of vanadium(IV) and vanadium(V) in the whole digestive system for the first time. Higher oral bioaccessibility of vanadium(IV) and vanadium(V) was determined in gastric and small intestinal phases demonstrating that their major roles for vanadium digestion and absorption. The decreasing order of the oral bioaccessibility of vanadium(IV) and vanadium(V) in each digestive phase was stomach, small intestine, large intestine and mouth. Higher oral bioaccessibility of vanadium(V) in the whole digestion indicated its higher risk potential for human than vanadium(IV). Lower oral bioaccessibility of vanadium(IV) and vanadium(V) determined in bionic digestion illustrated detoxicity potential of human body for ingested vanadium. Compared with soil and dust, higher digestion rate of vanadium in vanadium titanomagnetite concentrate fines indicated its higher risk for human, especially for mining workers. Based on vanadium oral bioaccessibility, hazard quotients of the vanadium were much less than the critical level suggested for no non-carcinogenic risks to the populations surrounding the sampling sites. Indeed, compared with the estimations based on total vanadium content, the incorporation of oral vanadium bioaccessibility into risk assessments could give more realistic information.

Elevated vanadium in the environment adversely affects organisms, including plants, animals, and humans. Plants act as the main conduit for environmental vanadium to enter the food chain, and simultaneously their growth response characteristics reflect vanadium toxicity efficacy for plants. The aim of the present study is to investigate lettuce (Lactuca sativa L.) growth involving morphological change, physiological adjustment, vanadium accumulation under vanadium stress, and the potential health risk (expressed as health risk index (HRI)) of adults and children who consume it. Lettuce was grown in nutrient solution with 0, 0.1, 0.5, 2.0, and 4.0 mg L

Continuous fluorine (F) accumulation in soil by anthropogenic activities leads to variously global environmental and health issues. Herein, 300 farmland soil samples were collected from different anthropogenic activity dominated districts for studying the distribution and related health risk of F in soils. Co-existing metal concentrations in soil samples were also analysed to evaluate the relationship between the distribution of F and metals in soil. The median value of the total F concentration of 488 mg kg

Vanadium is a nontrivial multi-valent metallic element, which has been increasingly used in modern society. The widespread application of vanadium promotes the rapid and sound development of the economy and society, simultaneously brings out increasingly prominent environmental problems, e.g., soil vanadium pollution. Therefore, the remediation problem of vanadium-contaminated soil has been received growing attention. Phytoremediation has become a significant constituent in vanadium-contaminated soil remediation attributable to its veritable merits such as cleanness, esthetics, cost-effectiveness, convenience, and sustainability. Phytoremediation is mainly dependent on hyperaccumulator plants, even though the actuality that the vast majority of hyperaccumulator plants are characterized by low biomass yield and slow-growing. Consequently, the intensity in screening the undiscovered hyperaccumulators should be strengthened. Meanwhile, it is imperative to further explore the vanadium accumulation and translocation characteristics of some non-hyperaccumulative but tolerant plants with moderate biomass to remediate the soil contaminated with vanadium. Taken together, further comprehensive researches of tolerance mechanisms of remedial plants against vanadium are quite necessary to decontaminate soils contaminated by vanadium efficiently.

Fluorine (F) is widely distributed in soils and is not an essential element for the normal growth of a plant, but in higher concentrations, it is toxic. However, the environmental toxicity of F in soils is still controversial. A pot experiment of broad bean and maize under the exposure to F was performed to elucidate F phytotoxicity and the response of the microbial community in soils. Six different levels (0, 200, 400, 600, 800, and 1000 mg kg–1) of sodium fluoride were spiked into the soil. The results revealed that the height of stem and root decreased with increasing concentration of F. Germination rate and fresh weight showed no difference in different treatments. At the treatment of 1000 mg kg−1 F, the degradation rates of pigments were 30.6%, 42.9%, and 35.7% for chlorophyll a, chlorophyll b, and total chlorophylls compared with control, respectively. All treatments showed a higher level of F accumulation in root than that in stem and leaf, and stem had a minimum F accumulation. Proteobacteria was the dominant species in bacteria and the relative abundance of Proteobacteria declined significantly with F exposure. Moreover, the number of microbial species both in bacteria and fungus was reduced for the increase of F. In general, our results revealed that high concentrations of F inhibited the growth of broad bean and maize but without visual symptom. The effect of fluorine on broad bean and maize is clarified in the present study which is instructive for agricultural safety.

Health risk of F in soil is of special concern due to the continuously elevated concentration of F in soil. However, there is still a dearth of risk assessments of F in soil based on in-vitro bioaccessibility posed by multiple exposure routes. Herein, the oral, inhalation, and dermal bioaccessibility of F in soil was firstly obtained by adapting and combining in-vitro methods, which then was introduced to remedy an information gap of a comprehensive risk of F in soil posed by a multi-exposure pathway. Combined in-vitro tests indicate the oral, inhalation, and dermal bioaccessibility of F was 13.15 ± 2.63%, 16.55 ± 2.63%, and 1.27 ± 0.73%, respectively. Plasma yielded a detoxic potential for the absorbed F after digesting in small intestine, while effects of enzymes, sweat, and food on the oral bioaccessibility of F were insignificant. Different with metals, the major dissolving phase of F was the interstitial fluid in the deep lung instead of in the alveolar macrophages intracellular environment. A potentially major release of F in the exocrine sweat was noted than in the apocrine sweat. Risk assessments based on the daily exposure incorporated with the in-vitro bioaccessibility suggested that compared with inhalation and dermal contact, oral ingestion was the main exposure route of F in soil to human. Present findings provide insights into the bioaccessibility and health risk of F in soil by multiple exposure routes, which are crucial for the risk control of F contamination in soil.

Fluorine (F) is widely dispersed in the environment and frequently used in industry and agriculture with a high migration ability. Thus, it is essential to understand the leaching characteristic of F in soil from industry and agriculture sources. Several sources of F pollutants in soil, including fertilizers, pesticides, phosphogypsum, and atmospheric deposition, were selected to investigate leaching characteristics of F in soil by leaching experiments. The addition of phosphate fertilizer and compound fertilizer (N:P:K = 20:10:15) enhanced the leachability of F in soil and the proportion of F leached out from soil treated by these fertilizers were 0.25% and 0.24%, respectively. However, unanticipated lower leachability of F appeared in compound fertilizer (N:P:K = 17:17:17), nitrogen fertilizer, dipterex, fluoroglycofen, fluopimomide, simulative dry deposition (YF3), and phosphogypsum loaded soils compared with additive-absent treatment. Although phosphogysum had a high F concentration, minimum proportion of F released (0.18%) was observed in phosphogypsum-coverd soil. The amounts of F leaching-out from surface soils (0–25 cm) treated with nitrogen fertilizer decreased 1.03 kg ha−1 comparing with blank control. Soil with phosphate fertilizer leached 5.47 kg F ha−1 a year, having the highest environment risk to deeper soil and groundwater. However, phosphogypsum and dry deposition of airbone F chemical had few effects on F leaching in soil. F-containing materials from agricultural process may leach more F from surface soils than industrial sources.

Vanadium (V) has been progressively studied due to its potential toxicity in the environment as a trace metal. A coexistence system of humic acid (HA) and silica was employed to simulate the main organic and inorganic components of soil. The adsorption and desorption characteristics of V by the system and the effects of several environmental conditions were investigated. The adsorption data were well described by the Langmuir and Freundlich models, illustrating that the adsorption of V on HA + silica was a monolayer adsorption. The kinetic study indicated that the main adsorption controlling step was a chemical reaction. The thermodynamic study showed that the adsorption was exothermic and spontaneous. The adsorption-desorption process was strongly dependent on the solution pH and HA concentration, while temperature (4–75 °C) and ionic strength (

Nano-hydroxyapatite (NHAP), possessing high defluoridation capacity, has been widely used to remove fluoride (F) from polluted water, but little is known about how it affects the bioavailability and toxicity of soil F towards plants. Here, the impact of NHAP (2% w/w) amendment on immobilization, speciation and accumulation of F was studied in a soil-plant system. The results revealed that the NHAP amendment worked effectively to reduce levels of water-soluble F (37.3%−87.8%) and increase available P (76.6%–147%). X-ray photoelectron spectroscopy analysis indicated that the formation of insoluble CaF2 and the ion exchange of F− with OH− into NHAP might be involved in the mechanism of F immobilization and soil pH elevation. Exposure to NHAP significantly decreased the abundance of Cyanobacteria in tested soils, and Gemmatimonadetes abundance in bulk soil was significantly higher than that in rhizosphere soil at 1,000 mg kg−1 F spiked level. Additionally, NHAP amendment decreased F accumulation in wheat shoots (9.10%–18.7%) and roots (3.88%–22.4%), which could mainly be attributed to the reduction of soil bioavailable F and the supplement of Ca from NHAP. These results suggest that NHAP could be a promising amendment to be applied to acidic soil contaminated with F.

Microbial treatment for vanadium contamination of soils is a favorable and environment-friendly method. However, information of the resistant mechanism of the strains in soils to vanadium, especially to tetravalent vanadium [vanadium(IV)], is still limited. Herein, potential of the vanadium(IV) biosorption and biotransformation of the strains (4K1, 4K2, 4K3 and 4K4) which were capable of tolerating vanadium(IV) was determined. For biosorption, the bioadsorption and the bioabsorption of vanadium(IV) occur on the bacterial cell wall and within the cell, respectively, were taken into consideration. Comparison of the vanadium(IV) adsorbed on the bacterial cell walls and remained in the cells after sorption indicated the major bacterial vanadium(IV) sorption role of the bioadsorption which was at least one order of magnitude higher than the bioabsorption amount. Isotherm study using various isotherm models revealed a monolayer and a multilayer vanadium(IV) biosorption by 4K2 and the others (4K1, 4K3 and 4K4), respectively. Higher biosorption was observed in acidic conditions than in alkaline conditions, and the maximum biosorption was 2.41, 9.35, 7.76 and 8.44 mg g−1 observed at pH 6 for 4K1, at pH 3 for 4K2, and at pH 4 for 4K3 and 4K4, respectively. At the present experimental range of the initial vanadium(IV) concentration, optimal biosorption capacity of the bacteria was observed at the vanadium(IV) level of 100–250 mg L−1. Different biotransformation level of vanadium(IV) in soils by the stains was observed during a 28-d pot incubation of the soils mixed with the strains, which can be attributed to the discrepancy of both soil properties and bacterial species. Present study can help to fill up the gaps of the insufficient knowledge of the vanadium(IV) resistant mechanism of the strains in soils.

With the extensive mining of vanadium (V) ore, much attention has been focused on soil V pollution and its hazards. This study was conducted to investigate the adsorption-desorption properties of V on silica under various conditions, such as initial vanadate (V(V)) concentration, reaction time, pH, ionic strength, and temperature. The Langmuir and Freundlich isotherm models were applied to describe the adsorption of V(V) on silica and the results indicate that the adsorption was mainly monolayer adsorption. The kinetic studies show that the mechanisms of V adsorption on and desorption from silica were different from one another. The main adsorption-desorption-controlling step was chemical reaction, whereas V adsorption on silica also involved the diffusion. The adsorption-desorption procedure was highly dependent on the initial V(V) concentration and solution pH. Adsorption of V(V) increased with an increase in initial concentration and the maximum adsorption capacity was observed at solution pH 3.0–5.0. At 29.1 mg L−1 initial V(V), and silica dosage 36.4 g L−1 at 25 °C, the adsorption amount reached maximum of 82.7 mg kg−1 and the corresponding desorption rate was 5.44%. Therefore, silica is an effective adsorbent which can fix V in the soil.

Two typical red soils were sequentially cultivated with celery (Apium graveolens L.) and Chinese cabbage (Brassica chinensis L.) in a greenhouse to determine the effect of lead (Pb) on plant availability of phosphorus (P) and potassium (K) in the soils. The concentrations of available P as estimated by the 0.05 mol L−1 HCl-0.025 mol L−1 (1/2 H2SO4) extraction and available K estimated by the NH4OAc extraction method in the crop-free soils were not affected by Pb treatment. Plant P concentrations in the above-ground part of celery and Chinese cabbage exposed to Pb were either lower or showed no significant difference to the control.

Information about geochemical behaviour of vanadium in soil to date is very limited. This study explored the characteristics and factors that affect vanadium adsorption-desorption by humic acid (HA...

Cadmium (Cd) has been identified as a very toxic heavy metal, which is widely present in the environment due to natural and anthropogenic emissions. Currently, in China, slight pollution of cultivated land is widespread and Cd is one of the top ranked inorganic pollutants in soils, which results in a great impact on the development of the economy and society. Therefore, there is an urgent need to develop an efficient and economical method to remediate Cd-polluted soil. This study focused on the development of new kinds of immobilizing soil amendments for the remediation of Cd-polluted soil. In addition, the immobilization capability of zinc (Zn) which may lead to increased toxicity of Cd was also investigated. The amendments, nanoiron–nanohydroxyapatite, nanoalumina–nanoiron and nanohydroxyapatite–nanoalumina, were prepared by the pairwise mixing of three raw materials: nanohydroxyapatite (nHAP), nanoiron (nFe) and nanoalumina (nAl2O3). The application rate, mixing ratio and pH of the amendments were studied to determine the optimal application conditions of the amendments. The results showed that, compared with the single materials of nHAP, nFe and nAl2O3, the immobilized efficiencies of Cd and Zn in soils by the pairwise mixed amendments were both significantly (p nFe > nHAP.

Vanadium (V) is widely used industrially, and plays an important role in the biosphere. Sensitive and reliable analytical methods to determine V in various kinds of samples are of extensive interes...

The prosperity and development of tannery industry have brought about rapid economic growth. However, the tannery landfill without anti-seepage measures in the early stage has generated masses of environmental hazards owing to the lack of awareness in environmental protection. Therefore, it is imperative to pay much attention to the understanding of environmental hazards from tannery waste. In this study, solid samples and groundwater samples were collected from a tannery landfill to study the effect of the characteristic pollutants produced by tanning on chromium distribution with other coexisting substances. The results showed that significant correlations were demonstrated between multiple coexisting substances (total organic carbon, total petroleum hydrocarbons, total nitrogen, Cr, F, Ca, Cu and Pb), indicating the possible same source or they coming from the same tannery production stage. The weights of positive effects and negative effects of coexisting substances on total Cr distribution in the profile decreased in the order: total nitrogen > Cu > Ca > Pb > total organic carbon > F > SO42– > Cd, and Ni > Cl > Hg, respectively. Moreover, the simulation of Visual MINTEQ showed that the cations were mainly bound to Cr as CrO42−, while the anions were bound to Cr3+. This study provided a new perspective on the selection of remediation strategies for Cr-contaminated sites to avoid secondary environmental pollution caused by the release of coexisting heavy metals.

Chromium (Cr) and tannin are two major pollutants in leather industry. However, little is known about the co-migration of leather tannins and Cr in soils. In this study, column experiments were conducted to estimate Cr leaching behavior from topsoil and the environmental risk of the leachate at various tannin dosages and different ways (tannin either directly adding to the Cr-contaminated soil or adding stepwise through simulated rain) into the soil. The total Cr concentration in leachate was positively related with tannin content in soil, while Cr (Ⅵ) concentration was negatively correlated. The maximum cumulative leaching efficiency of total Cr from soil after six leaching events was 44.65% with 3 mg/g tannin adding into soil directly, and the maximum cumulative leaching efficiency of Cr (Ⅵ) was 38.75% with simulated rain leaching Cr-contaminated soil. With 3 mg/g tannin adding into soil, tannin concentration in the top layer (0-7 cm) lost by 32.67% after leaching, the amount of decomposed tannin was 0.25 mg/g, excluding the amount of tannin in leachate (3.63 mg/L) and the original amount in the soil (0.34 mg/g), indicating a slow degradation under natural condition. Both of the total Cr and Cr (Ⅵ) concentration in each layer of the soil columns decreased under tannin treatments compared with control. Compared with tannin adding stepwise into simulated rain, adding tannin into soil significantly (p 0.05) affected the migration of Cr. Tannin increased the residual fraction while decreased the exchangeable fraction of Cr in the soils. Overall, this research can provide reference information for environmental risk assessment of contaminants in tanning sites.

Vanadium amassing in the soil increased with its widespread usage in multi-field. Elevated soil vanadium confers adverse effects on living organisms involved in plants, animals, and microorganisms. Moreover, vanadium can enter the human body through the food chain and lead to potential health risks stemming from its toxicity and carcinogenicity. Therefore, the remediation of soil contaminated by vanadium is imperative. Phytoremediation, a clean phytotechnology, is gaining increasing grace in modern society that prefers spirit-enjoy persuing. However, due to the blemishes of the remediation plants per se, the remediation efficiency relying on plants alone is not attractive. Therefore, the strengthened screening of vanadium accumulator and hyperaccumulator plants should step forward. Simultaneously, it is necessary to improve phytoremediation efficiency by some complementary measures, such as inoculating plant growth-promoting bacteria, vanadium reducing bacteria, and the proper application of plant growth regulators. Overall, microbe-assisted and moderate usage of plant growth-promoting factors are promising for the phytoremediation of vanadium-contaminated soil.