Magnetic resonance imaging-based prediction models for differentiating intraspinal schwannomas from meningiomas: classification and regression tree and random forest analysis.

Background: Due to the variations in surgical approaches and prognosis between intraspinal schwannomas and meningiomas, it is crucial to accurately differentiate between the two prior to surgery. Currently, there is limited research exploring the implementation of machine learning (ML) methods for distinguishing between these two types of tumors. This study aimed to establish a classification and regression tree (CART) model and a random forest (RF) model for distinguishing schwannomas from meningiomas. Methods: We retrospectively collected 88 schwannomas (52 males and 36 females) and 51 meningiomas (10 males and 41 females) who underwent magnetic resonance imaging (MRI) examinations prior to the surgery. Simple clinical data and MRI imaging features, including age, sex, tumor location and size, T1-weighted images (T1WI) and T2-weighted images (T2WI) signal characteristics, degree and pattern of enhancement, dural tail sign, ginkgo leaf sign, and intervertebral foramen widening (IFW), were reviewed. Finally, a CART model and RF model were established based on the aforementioned features to evaluate their effectiveness in differentiating between the two types of tumors. Meanwhile, we also compared the performance of the ML models to the radiologists. The receiver operating characteristic (ROC) curve, accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were used to evaluate the models and clinicians' discrimination performance. Results: Our investigation reveals significant variations in ten out of 11 variables in the training group and five out of 11 variables in the test group when comparing schwannomas and meningiomas (P<0.05). Ultimately, the CART model incorporated five variables: enhancement pattern, the presence of IFW, tumor location, maximum diameter, and T2WI signal intensity (SI). The RF model combined all 11 variables. The CART model, RF model, radiologist 1, and radiologist 2 achieved an area under the curve (AUC) of 0.890, 0.956, 0.681, and 0.723 in the training group, and 0.838, 0.922, 0.580, and 0.659 in the test group, respectively. Conclusions: The RF prediction model exhibits more exceptional performance than an experienced radiologist in discriminating intraspinal schwannomas from meningiomas. The RF model seems to be better in discriminating the two tumors than the CART model.

[Effect of PFOA on Oxidative Stress and Membrane Damage of Escherichia coli].

Perfluorooctanoic acid (PFOA) is widely used in industrial production because of its strong chemical stabilities and good hydrophobic and oleophobic properties. It was considered to be a widespread persistent organic pollutant in environment in recent years. The oxidative stress and membrane damage of Escherichia coli exposed to PFOA were measured by flow cytometry (FCM) and the toxic mechanism of PFOA was also preliminarily explored. The results showed that, under the stress of PFOA, the intracellular reactive oxygen species (ROS) content of E. coli increased, the unsaturation degree of fatty acid decreased, the malondialdehyde (MDA) content increased, the membrane permeability increased, the membrane potential decreased, and the activities of Na+K+-ATPase and Ca2+Mg2+-ATPase showed a compensatory increase first and then decreased. Therefore, owing to the stress of PFOA, the higher intracellular ROS in E. coli reacted with membrane unsaturated fatty acids by peroxidation,and then reduced cell membrane fatty acid saturation, accumulated MDA in cells, and further caused damage to cell membrane, reduced the ATPase activity, and eventually resulted in inactivation or apoptosis of E. coli. This study provided more evidence for the further study on environmental ecological toxicology of PFOA.

Effectiveness and intermediates of microcystin-LR degradation by UV/H2O2 via 265 nm ultraviolet light-emitting diodes.

Although the degradation of cyanotoxins by 254 nm UV/H2O2 has been well elucidated, the efficiency and mechanism involved are not necessarily true for other UV wavelengths. The degradation of microcystin-LR (MC-LR), a representative cyanotoxin, was explored by UV/H2O2 using 265 nm ultraviolet light-emitting diode (UV-LED). The results indicated that 265 nm UV/H2O2 treatment had a high removal efficiency of MC-LR ([MC-LR] = 0.1 µM, apparent rate constants reached 0.2077 min-1, half-time at 3.3 min). The qualitative analyses demonstrated that three novel intermediates, C48H74N10O15 (molecular weight = 1030.5335), C36H58N10O14 (854.4134), and C33H54N10O14 (814.3821), were generated in 265 nm UV/H2O2. Five published intermediates were also confirmed. The generative pathway of these products mainly involved free hydroxyl radical oxidation, resulting in consecutive hydroxyl substitutions and hydroxyl additions of unsaturated bonds in MC-LR. The toxicity of MC-LR was weaken with a relative low mineralization. The electrical energy per order values were calculated to be in the range of 0.00447 to 0.00612 kWh m-3 order-1 for 100-5000 µg L-1 MC-LR. Overall, 265 nm UV-LED/H2O2 can be used as an alternative effective technology to improve the removal efficiency of MC-LR in water.

Degradation of ciprofloxacin by 280 nm ultraviolet-activated persulfate: Degradation pathway and intermediate impact on proteome of Escherichia coli.

In this study, the degradation of ciprofloxacin (CIP) was explored using ultraviolet activated persulfate (UV/PS) with 280 nm ultraviolet light-emitting diodes (UV-LEDs), and the toxicological assessment of degrading intermediates was performed using iTRAQ labeling quantitative proteomic technology. The quantitative mass spectrum results showed that 280 nm UV/PS treatment had a high transformation efficiency of CIP ([CIP] = 3 µM, [S2O82-] = 210 µM, apparent rate constants 0.2413 min-1). The high resolution mass spectrum analyses demonstrated that the primary intermediates included C15H16FN3O3 (m/z 306.1248) and C17H18FN3O4 (m/z 348.1354). The former one was formed by the cleavage of piperazine ring, while the later one was generated by the addition of a hydroxyl on the quinolone backbone. The toxicological assessment demonstrated that 56 and 110 proteins had significant up regulations and down regulations, respectively, in the Escherichia coli exposed to degraded CIP compared to untreated CIP. The majority of up-regulated proteins, such as GapA, SodC, were associated with primary metabolic process rather than responses to stress and toxic substance, inferring that the moderate UV/PS treatment can reduce the antibacterial activity of CIP by incomplete mineralization. Consequently, these results provided a novel insight into the application of UV-LED/PS treatment as a promising removal methodology for quinolones.

Leaching heavy metals from the surface soil of reclaimed tidal flat by alternating seawater inundation and air drying.

Leaching experiments were conducted in a greenhouse to simulate seawater leaching combined with alternating seawater inundation and air drying. We investigated the heavy metal release of soils caused by changes associated with seawater inundation/air drying cycles in the reclaimed soils. After the treatment, the contents of all heavy metals (Cd, Pb, Cr, and Cu), except Zn, in surface soil significantly decreased (P < 0.05), with removal rates ranging from 10% to 51%. The amounts of the exchangeable, carbonate, reducible, and oxidizable fractions also significantly decreased (P < 0.05). Moreover, prolonged seawater inundation enhanced the release of heavy metals. Measurement of diffusive gradients in thin films indicated that seawater inundation significantly increased the re-mobility of heavy metals. During seawater inundation, iron oxide reduction induced the release of heavy metals in the reducible fraction. Decomposition of organic matter, and complexation with dissolved organic carbon decreased the amount of heavy metals in the oxidizable fraction. Furthermore, complexation of chloride ions and competition of cations during seawater inundation and/or leaching decreased the levels of heavy metals in the exchangeable fraction. By contrast, air drying significantly enhanced the concentration of heavy metals in the exchangeable fraction. Therefore, the removal of heavy metals in the exchangeable fraction can be enhanced during subsequent leaching with seawater.

[Biodegradation of Pyrene by Intact Cells and Spores of Brevibacillus brevis].

Biodegradation characteristics of pyrene by intact cells and spores of Brevibacillus brevis were investigated. The results revealed that the degradation efficiency of 1 mg · L(-1) pyrene by B. brevis intact cells reached 53% within 5 d. Four hydroxy metabolites were detected by LC-MS/MS during the degradation of pyrene by intact cells and intracellular enzymes, including 1-hydroxy-pyrene, 9- phenanthrol, α-naphthol and ß-naphthol. The amount of products first increased and then declined in the degradation system with intact cells, while the macromolecular metabolites showed a continuous accumulation tendency in the degradation system with intracellular enzymes, proving that some degrading enzymes of B. brevis could be induced by the products generated during the degradation, and then the enzymes induced could further degrade these degradation products. The amount of cells germinated from spores in MSM containing pyrene was 1.5 x 10(9) cells · L(-1), and the degradation rate of pyrene (1 mg · L(-1)) within 5 d reached 15%.

[Effects of Nitrate and CH4 on Anaerobic Oxidation of BETX in Landfill Cover Soils].

BETX is one of the important components of stink organic gases in landfills, which simultaneously release much of greenhouse CH4. The microorganisms in landfill cover soils are able to degrade CH4 and BETX. Therefore, improving the capacity of biological oxidation of microorganisms in landfill cover soils can effectively reduce and control pollution caused by landfill gases. Some electron acceptors can couple to anaerobic oxidation of methane and some organic pollutants, thus eliminating methane and organic substances. Based on the above theory, this research investigated the effect of nitrate (NO3-) and CH4 on anaerobic degradation of benzene series (toluene, xylene and isopropyl benzene) with coexistence of SO4(2-) in landfill cover soils through static incubation experiment. The results showed that BTEX inhibited the degradation of CH4 without adding nitrate, however, BTEX instead improved the removal of CH4 after nitrate addition. Although single addition of nitrate or CH4 could improve the removal of BTEX in landfill cover soils, adding both of them could improve the removal of BTEX better as the removal efficiencies for benzene, toluene and isopropyl benzene were respectively reached 65%, 88% and 82%, much higher than those of 53%, 76% and 31% when not adding nitrate and CH4. The process of anaerobic methane oxidation coupled to nitrate reduction was able to synchronously improve anaerobic oxidation of BETX.

[Influence of microcystin-LR on cell viability and surface characteristics of Pseudomonas putida].

In microcystin-LR (MC-LR) degradation system, the change in surface characteristics and cell viability of Pseudomonas putida was studied. The purpose of this study was to reveal the influence of MC-LR on P. putida and elucidate the toxicity of MC-LR on microorganisms. The result demonstrated that MC-LR enhanced the cytoplasmic membrane permeability, as well as affected the ion metabolism and protein release of P. putida. The soluble sugar and Na+, Cl-release increased with the rising concentration of MC-LR ranging from 0 mg x L(-1) to 2.0 mg x L(-1). Flow Cytometry Method(FCM) analysis revealed that MC-LR accelerated the death of P. putida, and the death rate increased with the ascending concentration of MC-LR. Compared with the control, the death rate on day 5 increased by nearly 30% when 2.5 mg x L(-1) MC-LR was added. Scanning electron microscopy (SEM) analysis showed that the cells were deformed under the toxicity of MC-LR. After 5-day exposure to 2.5 mg x L(-1) MC-LR, the majority of the cells were ruptured and the intracellular materials flew out. The cellular structure was severely damaged under this condition.

[Enhancing effect of Tween 80 on degradation of triphenyltin by Bacillus thuringiensis].

So far, the information regarding enhanced degradation and biodegradation mechanisms of TPhT, an endocrine disruptor, is severely limited. Whether dearylation during TPhT degradation occurs successively or synchronously is not revealed clearly. To deal with these problems, this study focused on the biodegradation of TPhT and its metabolites by Bacillus thuringiensis through the acceleration of Tween 80. The results showed that Tween 80 obviously increased the TPhT solubility. After degradation by cells in the presence of 80 mg L-1 Tween 80 for 2 d, the residual TPhT at 1 mg L-1 initially was decreased to 48.4%. During the biodegradation process, Tween 80 significantly reduced intracellular Na+, NH+4: and Mg2+ release, and increased extracellular Cl- , PO(3-)4 and K+ utilization. Metabolites analysis revealed that phenyltin biodegradation initially proceeded by cleaving the aromatic ring, not by splitting the covalent bonds between the benzene rings and tin atom. Ring-cleavage reactions in the benzenes of TPhT occurred individually and synchronously, producing diphenyltin, monophenyltin and tin accordingly.

[Biodegradation of triphenyltin and its effect on Klebsiella pneumoniae].

To investigate the pathway and mechanism of triphenyltin (TPhT) biodegradation by Klebsiella pneumoniae, and the effects of TPhT on cells during the degradation process, the alteration of carbon utilization ability of the strain after dealing with different concentrations of TPhT was studied by the Biolog method, and the degradation pathway of TPhT was explored by GC-MS and X-ray photoelectron spectroscopy (XPS). After degradation for 2 h, the nutrient utilization capacity of K. pneumoniae was significantly improved by 1 mg x L(-1) TPhT. Atomic force microscope observation found that exposure to TPhT changed the cellular morphology, inducing the apoptosis of some cells, but most of the cells still maintained intact and had smooth cell wall. The efficiencies of TPhT removal by intracellular enzyme were up to 66.0% within 120 h, which demonstrated that endoenzyme was more effective than the intact cells. The results of GC-MS and XPS revealed that during the biodegradation process, TPhT was transformed to diphenyltin, monophenyltin and finally inorganic tin.

[Characteristics and functional protein analysis of an effective decabromodiphenyl ether-degrading strain].

An effective decabromodiphenyl ether (BDE-209) degrading strain was isolated and identified as Enterococcus casseliflavus based on the 16S rRNA gene sequence analysis. The optimal conditions for strain growth were pH 7 and culture time of 48 h, respectively. E. casseliflavus has a good ability to degrade BDE-209. The biodegradation rate of 1 mg.L-1 BDE-209 by 1 g.L-1 E. casseliflavus reached the highest of 56. 7% after 4 days degradation with 5 mg.L-1 glucose as the additional carbon source. During the degradation process of BDE-209, SDS-PAGE demonstrated that some new extracellular proteins were induced under 2 mg.L-1 and 5 mg.L-1 BDE-209. As for the intracellular proteins, the quantity of protein expression varied, and some proteins even disappeared compared with the blank control. Two-dimensional electrophoresis steps for protein analysis detected 31 different protein points, demonstrating that during the degradation process, the conformation of some proteins which were related with degradation was changed, and resulted in the variation of type and content of the proteins.

[Isolation of an effective benzo [a] pyrene degrading strain and its degradation characteristics].

A strain which could utilize BaP as a sole carbon and energy source and efficiently degrade benzo[a] pyrene (BaP) was isolated from the contaminated sediments of Guiyu, Guangdong province, China. The strain was identified as Brevibacillus brevis based on physiological and biochemical experiments together with 16S rRNA sequence analysis. The experimental results showed that the biodegradation rate of BaP by B. brevis in 7 days was 51.35%. The study also demonstrated that pH, temperature, bacterial dosage, initial concentration of BaP and processing time were important factors for BaP degradation. B. brevis could tolerate wide pH and temperature ranges, from 2 to 12 degrees C and 25 to 40 degrees C, respectively. The optimum condition for BaP degradation was pH 7 and 25 degrees C. With the increase of B. brevis inoculation amount, the degradation efficacy displayed an initial increasing trend and then came to a plateau. And the increase of BaP concentration led to the enhancement of BaP degradation. Addition of salicylic, succinate and phthalate showed no obvious positive effect on BaP biodegradation. After degradation of BaP, the surface of B. brevis was wrinkled, and became depressed and deformed over time.

[Biodegradation of decabromodiphenyl ether by intracellular enzyme obtained from Pseudomonas aeruginosa].

The degradation characteristics of decabromodiphenyl ether (BDE-209) by crude enzyme from Pseudomonas aeruginosa were investigated. The results revealed that the degradation efficiency of the intracellular enzyme excreted from this bacterial strain reached 69.22% after incubation with 1 mg x L(-1) BDE-209 for 12 h. Temperature, pH, enzyme concentration and BDE-209 concentration all influenced the ability of crude enzyme to degrade BDE-209. When the BDE-209 concentration was 1 mg x L(-1), the optimal condition for enzymatic degradation was temperature 30 degrees C and pH 7.5, and the degradation rate increased with increasing enzyme concentration. The degradation process of BDE-209 by intracellular enzyme of the strain conformed to the first-order kinetic model. The highest reaction rate was achieved when the initial concentration of BDE-209 was 1 mg x L(-1) and the half-life of this substrate was 6.9 h. In addition, the biodegradation of BDE-209 can be well described by enzymatic reaction of high concentration substrate inhibition, with a maximum substrate utilization rate of 0.133 mg x (L x h)(-1), a Michaelis-Menten constant of 0.642 mg x L(-1), and an inhibitory constant of 1.558 mg x L(-1), respectively.

[Characteristic and ion exchanges during Cu2+ and Cd2+ biosorption by Stenotrophomonas maltophilia].

The characteristics of Cu2+ and Cd2+ biosorption by Stenotrophomonas maltophilia (S. maltophilia) under different biomass, metal concentration and glutaraldehyde content were studied and the correlations among metal biosorption, NO3- removal and ion release were analyzed. The mechanism was explored through ion biosorption, exchange, conversion and release. The experimental results demonstrated that S. maltophilia was an efficient strain to remove Cu2+ and Cd2+. The biosorption efficiencies of Cu2+ and Cd2+ achieved 96.3% and 83.9%, respectively after dealing with 0.05 mmol x L(-1) aqueous solutions for 120 min with dry biosorbent dosage of 0.2 g x L(-1). Cu2+ and Cd2+ biosorption by S. maltophilia included surface adsorption, transmembrane active transportation, bioaccumulation of NO3- and reduction of NO3- to NO2-. The intracellular transfer and reduction of NO3- to NO2- during biosorption by S. maltophilia were energy-consuming biological processes. It could also promote the release of Cl-, PO4(3-), SO-4(2-), Na+, NH4+, K+ and Ca2+. From FTIR investigation, involvement of various functional groups like acetylamino, hydroxyl and carboxyl in the binding of Cu2+ and Cd2+ was evident. Moreover, XPS results proved that the valence state of Cu2+ and Cd2+ did not changed by biosorption.

[Effects of nitrate on anoxic/anaerobic oxidation of methane in the aged refuse].

This work investigated the effects of nitrate on anoxic/anaerobic methane oxidation in the aged refuse landfilled 10-12 years by full-factor experiments. The results showed that under anoxic/anaerobic condition, nitrate could promote the removal of methane in the aged refuse. The contents of CH4 and NO3(-) -N had significant influences on the removal of CH4 and the generation of N2, and there were significant interactions as well (P < 0.05). The increasing initial CH4 content evidently enhanced the removal of CH4 and the production of N2. Furthermore, the addition of NO3(-) -N obviously improved the de-nitrification process. The results suggested that nitrate reduction could be coupled to anoxic/anaerobic oxidation of methane in the aged refuse. In the experimental condition, the effort of coupling was most effective when the concentrations of CH4 and nitrate were 30% and 110 mg x kg(-1), respectively.

[Effect of heavy metals on degradation of BDE-209 by white-rot fungus].

Effects and mechanisms of heavy metals Cu, Cd and Pb on the growth of white-rot fungus P. chrysosporium and its ability of BDE-209 degradation were studied. The results showed that low concentrations of heavy metals (< or = 1 mg x L(-1)) stimulated the growth of P. chrysosporium with the order of Cd > Pb > Cu when 1 mg x L(-1) of each heavy metal was concerned, while high concentrations (> 1 mg x L(-1)) depressed it. P. chrysosporium degraded BDE-209 efficiently with degradation efficiency reaching 69.7% after 7 days. The presence of heavy metals significantly influenced the capability of P. chrysosporium to decompose BDE-209 (P < 0.05). Low concentrations of Cu (< or = 1 mg x L(-1)) and Cd (< or = 0.5 mg x L(-1)) accelerated the degradation of BDE-209 and the degradation efficiency was enhanced from 69.7% to 84.4% when 1 mg x L(-1) Cu was present, while Pb had negative effect. On the other hand, all three metals under high concentrations (> 1 mg x L(-1)) showed depressed effects on the degradation in the order of Cd > Pb > Cu. The growth of P. chrysosporium did not completely positively correlate with the degradation capability of BDE-209. The degradation of BDE-209 by P. chrysosporium conformed to the first-order kinetic model. The reaction rate constant k raised firstly and then declined with increasing concentrations of Cu and Cd, and the highest k of 0.321 2 achieved in the presence of 1 mg x L(-1) Cu. By contrast, the constant k declined all the way when Pb existed. A further investigation into the effects of heavy metals on degradation of BDE-209 by extracellular enzymes derived from P. chrysosporium was conducted, and the distance correlation analysis of the degradation by extracellular enzymes and the whole cell was carried out. The results demonstrated that the degradation by extracellular enzymes and the whole cell was 63.7%, 69.7% separately, showing no significant difference of degradation capability between them, which proved that the extracellular enzymes played dominating role in the degradation of BDE-209. Furthermore, the distance correlation coefficient R were all greater than 0.9 when three heavy metals existed, certificating that heavy metals affected the degradation of BDE-209 through the interaction between extracellular enzymes and heavy metals.

[Effect of heavy metal ions on triphenyltin enzymatic degradation].

The influence of different metal ions and different forms of addition on triphenyltin enzymatic degradation was investigated under conditions using enzyme obtained from Klebsiella pneumoniae. The objective of this study is to illuminate the mechanism of enzymatic degradation of triphenyltin (TPhT). The results demonstrated that the strain was able to tolerate K+, Mg2+, CU2+, Ca2+ and Fe3+ at high concentrations. High concentrations of Zn2+ and Fe2+ had some toxic effects on the strain, thus affecting its growth. The endoenzyme activity was enhanced by metal ions such as K+, Mg2+, Zn2+, Cu2+ and Fe2+ at certain concentrations. In the presence of 30 mg/L of Mg2+, the removal percentage of TPhT was up to 77.22%. Fe3+ restrained the enzyme activity at certain concentrations. Adding K+, Mg2+, Zn2+, Cu2+ into medium can promote the production of enzyme, among which Mg2+ demonstrated up to 85.66% of removal percentage of TPhT, suggesting some metal ions at the appropriate concentration range can be used as enzyme activator for the enzymatic degradation of triphenyltin. Metal ions showed no relevant impact on the cell growth and enzyme production. Certain metal ions can only serve as activators of endoenzyme and exhibited no similar effect towards exoenzyme.

[Characteristics of biodegradation of triphenyltin by Rhodopseudomonos spheroids].

The biodegradation of triphenyltin (TPT) by Rhodopseudomonos spheroids was investigated in this study. The results illuminated that R. spheroids was an effective strain for the biodegradation of TPT. The maximum removal ratio was attained when the growth temperature of R. spheroids was 30 degrees C. After treating for 3 hours, the removal ratios of 3 mg x L(-1) TPT were 13.82% to 47.29% using 0.49 g x L(-1) (based on dry weight) biomass of R. spheroids. The experiments on biodegradation of TPT were carried out in double-distilled water, simulated seawater,culture medium and river water, respectively. The results demonstrated that river water was optimal for the biodegradation since the indigenous microorganisms in water synergistically increased the removal ratios of TPT. Extracellular enzyme produced by R. spheroids was also effective on the degradation of TPT, and 71.64% of TPT was degraded by this way within 24 hours. The experiments also revealed that the biodegradation process of TPT included biosorption by cell wall, TPT entering cells, and initial degradation by intracellular enzyme, then the TPT and intermediate products backing out of cells to be degraded by extracellular enzyme.

Biodegradation of anthracene by Aspergillus fumigatus.

An anthracene-degrading strain, identified as Aspergillus fumigatus, showed a favorable ability in degradation of anthracene. The degradation efficiency could be maintained at about 60% after 5d with initial pH of the medium kept between 5 and 7.5, and the optimal temperature of 30 °C. The activity of this strain was not affected significantly by high salinity. Exploration on co-metabolism showed that the highest degradation efficiency was reached at equal concentration of lactose and anthracene. Excessive carbon source would actually hamper the degradation efficiency. Meanwhile, the strain could utilize some aromatic hydrocarbons such as benzene, toluene, phenol etc. as sole source of carbon and energy, indicating its degradation diversity. Experiments on enzymatic degradation indicated that extracellular enzymes secreted by A. fumigatus could metabolize anthracene effectively, in which the lignin peroxidase may be the most important constituent. Analysis of ion chromatography showed that the release of anions of A. fumigatus was not affected by addition of anthracene. GC-MS analysis revealed that the molecular structure of anthracene changed with the action of the microbe, generating a series of intermediate compounds such as phthalic anhydride, anthrone and anthraquinone by ring-cleavage reactions.

[Cation exchanges during the process of Cd(2+) absorption by Alfalfa in aqueous solutions].

A hydroponic experiment was conducted to investigate the cation exchanges during the process of Cd2+ absorption by Alfalfa in aqueous solution. The absorption efficiency of Alfalfa plants with 0-10 mg x L(-1) Cd2+ treatments, changes of Na+, K+, Mg2+, Ca2+ and NH4(+) concentration, and the variation of pH values at different absorption time (0, 1, 2, 4, 8, 12, 24 and 72 h) were studied separately. The multiple linear regressions between Cd2+ absorption and cation variation were analyzed. The results indicated that when Cd2+ concentrations were 0.1, 1, 5, 10 mg x L(-1), the absorption efficiencies of Cd2+ by Alfalfa after 72 h were 85.86%, 52.14%, 15.97% and 7.81%. Cation exchange was involved in the removal of Cd2+ by Alfalfa in aqueous solution. Except for NH4(+), the concentrations of cationic metals Na+, K+, Mg2+ and Ca2+ in aqueous solution increased over time, which increased 11.30% - 61.72%, 21.44% - 98.73%, 24.09% - 8.90% and 37.04% - 191.96%, respectively. Kinetic studies illuminated that the release of Na+, K+, Mg2+ and Ca2+ by Alfalfa in Cd2+ solution with initial concentrations of 0, 0. 1, 1, 5, 10 mg x L(-1) best fitted pseudo-second-order equation,while the NH4(+) release fitted this model when Cd2+ concentrations were 1, 5, 10 mg x L(-1). The gradual decrease of pH during adsorption of Cd2+ by Alfalfa was observed. As the competition ion of Cd2+, H+ might affect the capacity of Alfalfa root system to absorb Cd2+. The ternary linear equation results demonstrated that the content of Cd2+ absorption by Alfalfa strongly related with the release of Ca2+, Mg2+, Na+. And this exchange mainly occurred among Cd2+ and divalent cations.