Effect of In Vivo and in Vitro Treatment with Arsenite on Rat Hepatic Mitochondrial and Microsomal Enzymes

The effects of arsenite on activities of several enzymes including mitochondrial pyruvate dehydrogenase(PDH) and succinate dehydrogenase(SDH) ,microsomal cytochrome P450 and b5 , NAD(P)H cytochrome C reductase and glutathione S-transferase were studied. The effects of arsenite on the mitochondrial membrane lipid peroxidation(LPO), the content of hepatic cytosol reduced glutathione and the activity of glutathione peroxidase was also investigated in rats.The results indicated that the activities of mitochondrial PDH and SDH were inhibited to 59% and 57% of the control activities respectively after arsenite was administered by intraperitoneal injection(i. p.) for 7 consecutive days at a dose of 20 mg/kg. Administration of arsenite led to a potential decrease of GSH content.The increase in lipid peroxidation of liver mitochondrial membrane prepared from rats treated with arsenite was also observed(P<0. 05) . Arsenite did not appear to affect the liver cytosolic glutathione peroxidase and microsomal enzyme activities in vivo. In in vitro test, liver mitochondria and cytosol were treated with arsenite , which led to a decreased SDH activity and GSH content and increase of mitochondrial LPO in a dose-dependent pattern that was similar to the results obtained in in vitro experiments. Selenite played a significant antagonistic role in effects of arsenite either in vivo or in vitro on the activities of mitochondrial PDH and SDH, and the content of mitochondrial LPO and cytosolic GSH. This results suggested that the toxic effects of arsenite on rat were associated with increased levels of LPO and the injured SH group in body caused by arsenite.

Ameliorating effects of Raphanus sativus leaves on sodium arsenite-induced perturbation of blood indices in Swiss albino mice

Objective: To evaluate the ameliorating effects of Raphanus sativus leaves(RSL)against sodium arsenite(Sa)-induced adverse effects through mice experiments.Methods: Swiss albino mice were divided into four equal groups: control, Sa, RSL,RSL + Sa. Sa(10 mg/kg body weight/day), and powder form of RSL(50 mg/kg body weight/day) were provided as food supplement orallty. Blood indices were measured using commercially available kits through colorimetric methods.Results: It was observed that lactate dehydrogenase, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase activities were significantly(P < 0.05)higher in Sa-treated mice than those in the control group. RSL significantly reduced Sainduced elevation of the activities of these enzymes in serum significantly(P < 0.05).Serum butyrylcholinesterase activity and high density lipoproteins cholesterol levels in Satreated mice were significantly(P < 0.05) lower than the control group, and the food supplementation of RSL could significantly(P < 0.05) prevent the reduction of Sa-mediated serum butyryl cholinesterase activity and high density lipoproteins cholesterol levels. RSL could also reduce the Sa-induced elevation of serum urea level significantly(P < 0.05).Conclusions: Results of this study suggest the protective or ameliorating effects of RSL on Sa-induced perturbation of blood indices are related to the hepatic, cardiovascular and kidney dysfunction. Therefore, RSL may be useful to reduce arsenic toxicity in human in the future.

Absorption of Arsenite on Several Iron (Hydro-)Oxides and Impact from Pre-processing Methods

The absorption reactions of arsenite on Fe （hydro-）oxides are studied. The three absorbent types are Fe（OH）3 gel and two Fe （hydro-）oxides, in which the Fe（OH）3 gel was dried in a microwave oven under vacuum at 80℃. It is found that pH changes from 9.71 to 10.36 in 6 minutes after the Fe （OH）3 gel was mixed with NaAsO2 solution, as the arsenite replaces the OH- in goethite and Fe（OH）3. At the 40th minute after the start of the reaction, pH decreases, which is most probably because that the monodentate surface complex of absorbed arsenite has changed into mononuclear-bidentate complex and released proton. The decline in pH values indicates not the end of the absorption but a change in the reaction type. Temperature and dissolved gas has little effect on these two types of reactions. The total absorption of arsenite increases after the absorbent is irradiated with ultrasound, which also lead to difficulty in separating the solids from solution. The absorption capacity for arsenite of Fe（OH）3 gel dried in a microwave oven under vacuum is 53.18% and 17.22% respectively better than that of Fe （OH）3 gel and gel dried at 80℃. The possible reasons are that the water molecules in the gel vibrates with high frequency under the effect of microwave irradiation, thereby producing higher porosity and improved surface activity.

Enhanced Arsenite Removal Using Bifunctional Electroactive Filter Hybridized with La(OH)_(3)

A bifunctional electroactive filter was rationally fabricated for simultaneous oxidation and sequestration of toxic trivalent arsentic As(Ⅲ).A novel nanoscale La(OH)_(3) modified electrochemical carbon nanotube(CNT)network filter was prepared by a facile electrodeposition strategy.The As(Ⅲ)decontamination kinetics and adsorption capacity were both found to increase with the flow rate(1.5-6.0 mL/min)and the applied voltage(0-2.5 V).The CNT filter hybridized with La(OH)_(3)(CNT-La(OH)_(3))has demonstrated the ultra-high adsorption capacity of 750.2 mg/g for As(Ⅲ),which is ascribed to the combined role of sufficient adsorption sites,flow-through filtration and electric field.XPS analysis revealed that the As(Ⅲ)decontamination mechanism involved a two-step adsorption-oxidation process.The formation of inner-sphere La-O-As complexes,ligand exchange and electro-adsorption are all parts of the As(Ⅲ)adsorption process.The adsorbed neutrally-charged As(Ⅲ)was further oxidized to negatively-charged As(V)when aided by an electric field,which could be effectively sequestrated by La(OH)_(3).The CNT-La(OH)_(3) filter shows high stability under alkaline conditions and can be regenerated with dilute NaOH solution.In this study,all experiment results have demonstrated a promising and effective CNT-La(OH)_(3) electrochemical filter for As(Ⅲ)pollution minimization.

Enhanced Removal of Arsenite from Ground Water by Adsorption onto Heat-Treated Rice Husk

The effect of heat treatment for rice husk was investigated on the removal of arsenite in ground water by the adsorption onto the rice husk surface. The heat treatment was performed at the temperature from 80oC to 300oC in the closed system under anoxic environment. The continuous adsorption column method was applied for the removal of arsenite. The removal efficiency (75%) with rice husk treated at 150oC was better compared to those (54%) obtained with untreated rice husk. Therefore, the heat treatment of rice husk at relatively low temperature was effective for the enhancement of arsenic removal from water. The treatment conditions of As removal from aqueous solution were optimized. The developed treatment technique was applied into the real ground water sample in Bangladesh. The As concentration in sample water after treatment was approximately 18 and 8 μg/L, which was below the WHO guideline value of maximum admissible level of arsenic in ground water for Bangladesh (50 μg/L). The developed technique might become a potential avenue for simple and low cost arsenic removal methods.

Evaluation of the Therapeutic Significance of Arsenite and Thalidomide in Patients with Myelodysplastic Syndrome

Objective:To analyze the therapeutic significance of arsenite and thalidomide in patients with myelodysplastic syndrome.Methods:From August 2021 to August 2022,80 patients with myelodysplastic syndrome were selected and randomly divided into two groups.In the control group,the drug used was thalidomide tablets,whereas in the observation group,the drug used was arsenite and thalidomide.The treatment effect was observed and evaluated.Results:Before treatment,there was no statistical significance in the blood and serological indices between the two groups.After treatment,the observation group showed better blood and serological indices than the control group(P<0.05).The clinical efficacy of the observation group was 77.5%,while that of the control group was 50.0%.The observation group had significantly better treatment effect(P<0.05).The incidence of adverse effects in the observation group and the control group was 5.0%and 20.0%,respectively.The observation group had significantly fewer adverse effects(P<0.05).Conclusion:In the treatment of patients with myelodysplastic syndrome,the use of arsenite on the basis of thalidomide can effectively improve the treatment effect and optimize the levels of various blood and serological indices,with fewer adverse effects and a relatively high safety profile.

Quantification of the redox properties of microplastics and their effect on arsenite oxidation

Microplastics have attracted global concern.The environmental-weathering processes control their fate,transport,transformation,and toxicity to wildlife and human health,but their impacts on biogeochemical redox processes remain largely unknown.Herein,multiple spectroscopic and electrochemical approaches in concert with wet-chemistry analyses were employed to characterize the redox properties of weathered microplastics.The spectroscopic results indicated that weathering of phenol-formaldehyde resins(PFs)by hydrogen peroxide(H2O2)led to a slight decrease in the content of phenol functional groups,accompanied by an increase in semiquinone radicals,quinone,and carboxylic groups.Electrochemical and wet-chemistry quantifications,coupled with microbial-chemical characterizations,demonstrated that the PFs exhibited appreciable electron-donating capacity(0.264-1.15 mmol e-g^(-1))and electron-accepting capacity(0.120-0.300 mmol e-g^(-1)).Specifically,the phenol groups and semiquinone radicals were responsible for the electron-donating capacity,whereas the quinone groups dominated the electron-accepting capacity.The reversible redox peaks in the cyclic voltammograms and the enhanced electron-donating capacity after accepting electrons from microbial reduction demonstrated the reversibility of the electron-donating and-accepting reactions.More importantly,the electron-donating phenol groups and weathering-induced semiquinone radicals were found to mediate the production of H2O2 from oxygen for arsenite oxidation.In addition to the H2O2-weathered PFs,the ozone-aged PF and polystyrene were also found to have electron-donating and arsenite-oxidation capacity.This study reports important redox properties of microplastics and their effect in mediating contaminant transformation.These findings will help to better understand the fate,transformation,and biogeochemical roles of microplastics on element cycling and contaminant fate.

Adsorption of arsenate and arsenite from aqueous solutions by cerium-loaded cation exchange resin

The removal of arsenic from water and wastewater is obligatory. Resin is one of the most effective adsorbents for the removal of arsenic. In order to improve the adsorption capacity of resin, a new cerium-loaded cation exchange resin arsenic adsorbent was prepared by impregnating cerium into the cation exchange resin. Batch adsorption experiments under various conditions, such as time, temperature, pH and with coexisting ions were carried out to evaluate the adsorption characteristics of cerium-loaded resin in the removal of As（V） and As（III） from aqueous solutions. The results showed that the adsorption kinetics of As（V） and As（III） obeyed a pseudo second-order kinetic model and the adsorption rate constants were 0.3159 and 0.5215 g.mg-1-min-1, respectively. The adsorption of As（V） followed the Freundlich adsorption isotherm model and the adsorption isotherm data for As（III） fitted well to the Langmuir equation model. The adsorption capacities were 1.0278 mg/g for As（V） and 2.5297 mg/g for As（Ill）. Both the adsorption of As（V） and As（Ill） were found to be pH sensitive and the optimum pH was found to be 5-6. Except for the phosphate ion, the coexisting anionics, such as nitrate, chlorate, sulphate and carbonate, showed no remarkable effect on As（V） and As（ill） adsorption. The desorption and regeneration study showed that the adsorption capacity of Ce-loaded resin for As（V） and As（Ill） could be restored to 97.80% and 69.61%, respectively, using 0.5 moFL sodium hydroxide solution.

Arabidopsis NIP3;1 Plays an Important Role in Arsenic Uptake and Root-to-Shoot Translocation under Arsenite Stress Conditions

In Arabidopsis, the nodulin 26-like intrinsic protein （NIP） subfamily of aquaporin proteins consists of nine members, five of which （NIP1;1, NIP1;2, NIP5;1, NIP6;1, and NIP7;1） were previously identified to be perme- able to arsenite. However, the roles of NIPs in the root-to-shoot translocation of arsenite in plants remain poorly understood. In this study, using reverse genetic strategies, Arabidopsis NIP3;1 was identified to play an important role in both the arsenic uptake and root-to-shoot distribution under arsenite stress condi- tions. The nip3;1 loss-of-function mutants displayed obvious improvements in arsenite tolerance for aboveground growth and accumulated less arsenic in shoots than those of the wild-type plants, whereas the nip3;1 nip1;1 double mutant showed strong arsenite tolerance and improved growth of both roots and shoots under arsenite stress conditions. A promoter-β-glucuronidase analysis revealed that NIP3; 1 was ex- pressed almost exclusively in roots （with the exception of the root tips）, and heterologous expression in the yeast Saccharomyces cerevisiae demonstrated that NIP3;1 was able to mediate arsenite transport. Taken together, our results suggest that NIP3;1 is involved in arsenite uptake and root-to-shoot translocation in Arabidopsis, probably as a passive and bidirectional arsenite transporter.

Removal of arsenite by reductive precipitation in dithionite solution activated by UV light

This study investigates the removal of arsenite（As（III）） from water using dithionite activated by UV light. This work evaluated the removal kinetics of As（III） under UV light irradiation as affected by dithionite dose and light intensity, and characterized the nature of the precipitated solids using XPS and SEM-EDS. Photolysis of dithionite was observed by measuring dithionite concentration using UV absorbance at 315 nm. This study also investigated the effect of UV light path length on soluble As concentrations to understand resolubilization mechanisms. Total soluble As concentrations were observed to decrease with reaction time due to reduction of arsenite to form solids having a yellow-orange color.The removal mechanism was found to be reductive precipitation that formed solids of elemental arsenic or arsenic sulfide. However, these solids were observed to resolubilize at later times after dithionite had been consumed. Resolubilization of As was prevented and additional As removal was obtained by frequent dosing of dithionite throughout the experiment. As（III） removal is attributed to photolysis of dithionite by UV light and production of reactive radicals that reduce As（III） and convert it to solid forms.

Ligand effects on arsenite removal by zero-valent iron/O2: Dissolution, corrosion, oxidation and coprecipitation

Ligands may increase the yields of reactive oxygen species(ROS)in zero-valent iron(ZVI)/O2 systems.To clarify the relationship between the properties of ligands and their effects on the oxidative removal of contaminants,five common ligands(formate,acetate,oxalate,ethylenediaminetetraacetic acid(EDTA),and phosphate)as well as acetylacetone(AA)were investigated with arsenite(As(III))as the target contaminant at three initial p H values(3.0,5.0,and 7.0).The addition of these ligands to the ZVI/O2 system resulted in quite different effects on As(III)removal.EDTA enhanced the oxidation of As(III)to arsenate(As(V))but inhibited the removal of As(V).Oxalate was the only ligand in this work that accelerated both the removal of As(III)and As(V).By analyzing the ligand effects from the four aspects:dissolution of surface iron(hydr)oxides,corrosion of ZVI,reaction with ROS,and interference with precipitation,the following properties of ligands were believed to be important:ability to provide dissociable protons,complexation ability with iron,and reactivity with ROS.The complexation ability is a double-edged sword.It could enhance the generation of ROS by reducing the reduction potential of the Fe(III)/Fe(II)redox couple,but also could inhibit the removal of arsenic by coprecipitation.The elucidated relationship between the key property parameters of ligands and their effects on the ZVI/O2 system is helpful for the rational design of effective ZVI/ligand/O2 systems.

Characterization of Fe5(AsO3)3Cl2(OH)4·5H2O,a new ferric arsenite hydroxychloride precipitated from FeCl3-As2O3-HCl solutions relevant to arsenic immobilization

Tooeleite(Fe6(As03)4 SO4(OH)4·4 H2 O)is widely precipitated for direct As(III)removal from sulfate-rich industrial effluents.However,whether or not Fe(III)-As(III)-Cl(-I)precipitate is produced in chloridizing leaching media for As immobilization is almost unknown.This work founded the existence of ferric arsenite(hydroxy)chloride as a new mineral for As(III)removal.Its chemical composition and solid characterization were subsequently studied by using scanning electron microscope with an energy dispersive spectrometer(SEM-EDS),X-ray diffraction(XRD),infrared(FT-IR),Raman spectroscopy and thermogravimetric(TG)curve.The results showed the formation of a yellow precipitate after 3-days reaction of Fe(III)/As(III)with molar ratio≈1.7 in chloride solution at pH 2.3 neutralized with NaOH.Compared with tooeleite,chemical analysis and solid characterization indicated that Cl(-I)replaces S04(-II)producing ferric arsenite hydroxychloride with formula Fe5(As03)3-Cl2(OH)4·5 H2 O.This new plate shaped solid showed better crytallinity than tooeleite,although it has similar morphology and characteristic bands to tooeleite.The FT-IR bands at 628,964 cm-1 and the Raman bands at 448,610,961 cm-1 were assigned to Fe-O or As(Ⅲ)-O-Fe or As(Ⅲ)-O bending/stretching vibration,indicating that both arsenite and chloride substituted for the position of sulfate for ferric arsenite hydro xychloride produced due to the lack of the SO42-vibrations.Cl-(I)also contributed to increase As removal efficiency in aqueous sulfate media under acidic pH conditions via the probable formation of sulfatechloride ferric arsenite.

Examination of in vivo mutagenicity of sodium arsenite and dimethylarsinic acid in gpt delta rats

Arsenic is a well-known human bladder and liver carcinogen, but its exact mechanism of carcinogenicity is not fully understood. Dimethylarsinic acid（DMAV） is a major urinary metabolite of sodium arsenite（i As~Ⅲ） and induces urinary bladder cancers in rats. DMAVand i As~Ⅲare negative in in vitro mutagenicity tests. However, their in vivo mutagenicities have not been determined. The purpose of present study is to evaluate the in vivo mutagenicities of DMAVand i As~Ⅲin rat urinary bladder epithelium and liver using gpt delta F344 rats.Ten-week old male gpt delta F344 rats were randomized into 3 groups and administered 0,92 mg/L DMAV, or 87 mg/L i As~Ⅲ（each 50 mg/L As） for 13 weeks in the drinking water. In the mutation assay, point mutations are detected in the gpt gene by 6-thioguanine selection（gpt assay） and deletion mutations are identified in the red/gam genes by Spi-selection（Spi-assay）. Results of the gpt and Spi-assays showed that DMAVand i As~Ⅲhad no effects on the mutant frequencies or mutation spectrum in urinary bladder epithelium or liver. These findings indicate that DMAVand i As~Ⅲare not mutagenic in urinary bladder epithelium or liver in rats.

Bacterial community succession during the enrichment of chemolithoautotrophic arsenite oxidizing bacteria at high arsenic concentrations

To generate cost-effective technologies for the removal of arsenic from water, we developed an enrichment culture of chemolithoau- totrophic arsenite oxidizing bacteria （CAOs） that could effectively oxidize widely ranging concentrations of As（III） to As（V）. In addition, we attempted to elucidate the enrichment process and characterize the microbial composition of the enrichment culture. A CAOs enrichment culture capable of stably oxidizing As（III） to As（V） was successfully constructed through repeated batch cultivation for more than 700 days, during which time the initial As（iiI） concentrations were increased in a stepwise manner from 1 to 10-12 mmol/L. As（III） oxidation activity of the enrichment culture gradually improved, and 10-12 mmol/L As（III） was almost completely oxidized within four days. Terminal restriction fragment length polymorphism analysis showed that the dominant bacteria in the enrichment culture varied drastically during the enrichment process depending on the As（III） concentration. Isolation and characterization of bacteria in the enrichment culture revealed that the presence of multiple CAOs with various As（Ⅲ） oxidation abilities enabled the culture to adapt to a wide range of As（Ⅲ） concentrations. The CAOs enrichment culture constructed here may be useful for pretreatment of water from which arsenic is being removed.

Microcalorimetric Study on the Effect of Sodium Arsenite on Metabolic Activity of Mitochondria Isolated from Carassius auratus Liver Tissue

Metabolic thermogenic curves of mitochondria isolated from liver tissue of Carassius auratus and the effect of different concentration of NaAsO2 on it were investigated by TAM air isothermal microcalorimeter, ampoule method, at 28.00 ℃. From the thermogenic curves, activity recovery rate constants k, the maximum heat production rate （Pmax） and the total heat produced （Q） were obtained. The values of k and Pmax decline gradually with the increase of the concentration of NaAsO2, and both of the values of Pmax and k are highly correlated to the concentration of NaAsO2. When concentration of NaAsO2 reached 16.0 μg/mL, the maximum heat production rate dropped to 70.8% of the control group, and the corresponding percentage of k was 71.4% of the control group. This experimental result indicates that the addition of NaAsO2 has restrained the metabolic activities of mitochondria in vitro.

Significant Phenomena Observed in the Molecule-Ion Adduct System of Sodium Arsenite with aoCyclodextrin

The data of 1H nuclear magnetic resonance and molar conductivity prove that there is a molecule-ion interaction between a-cyclodextrin （a-CD） and sodium arsenite （SA）, and the interaction site is different from that between β-CD and SA. The packing mode of a-CD molecules after adduct with SA is changed from cage to channel type. Several experimental phenomena from thermogravimetric analyses and gas chromatography coupled to time-of-flight mass spectrometry measurements reveal that the presence of SA has led to a large change of thermal decomposition behavior of a-CD, and vice versa. The current work reveals the particularity of the interaction between SA and a-CD, which would provide new insight into the understanding of molecule-ion interactions.

SUMO E3 ligase SIZ1 negatively regulates arsenite resistance via depressing GSH biosynthesis in Arabidopsis

Arsenic is a metalloid toxic to plants,animals and human beings.Small ubiquitin-like modifier(SUMO)conjugation is involved in many biological processes in plants.However,the role of SUMOylation in regulating plant arsenic response is still unclear.In this study,we found that dysfunction of SUMO E3 ligase SIZ1 improves arsenite resistance in Arabidopsis.Overexpression of the dominant-negative SUMO E2 variant resembled the arsenite-resistant phenotype of siz1 mutant,indicating that SUMOylation plays a negative role in plant arsenite detoxification.The siz1 mutant accumulated more glutathione(GSH)than the wild type under arsenite stress,and the arsenite-resistant phenotype of siz1 was depressed by inhibiting GSH biosynthesis.The transcript levels of the genes in the GSH biosynthetic pathway were increased in the siz1 mutant comparing with the wild type in response to arsenite treatment.Taken together,our findings revealed a novel function of SIZ1 in modulating plant arsenite response through regulating the GSH-dependent detoxification.

PIN FORMED 2 Modulates the Transport of Arsenite in Arabidopsis thaliana

Arsenic contamination is a major environmental issue,as it may lead to serious health hazard.The reduced trivalent formof inorganic arsenic,arsenite,is in generalmore toxic to plants comparedwith the fully oxidized pentavalent arsenate.Theuptakeof arsenite inplants hasbeenshown tobemediatedthrough a large subfamily of plant aquaglyceroporins,nodulin 26-like intrinsic proteins(NIPs).However,the efflux mechanisms,as well as themechanismof arsenite-induced root growth inhibition,remain poorly understood.Usingmolecular physiology,synchrotron imaging,and root transport assay approaches,we show that the cellular transport of trivalent arsenicals inArabidopsis thalianais stronglymodulatedbyPINFORMED2(PIN2)auxin efflux transporter.Root transport assay using radioactive arsenite,X-ray fluorescence imaging(XFI)coupled with X-ray absorption spectroscopy(XAS),and inductively coupled plasma mass spectrometry analysis revealed that pin2 plants accumulate higher concentrations of arsenite in roots comparedwith the wild-type.At the cellular level,arsenite specifically targets intracellular sorting of PIN2 and thereby alters the cellular auxin homeostasis.Consistently,loss of PIN2 function results in arsenite hypersensitivity in roots.XFI coupled with XAS further revealed that loss of PIN2 function results in specific accumulation of arsenical species,but not the other metals such as iron,zinc,or calcium in the root tip.Collectively,these results suggest that PIN2 likely functions as an arsenite efflux transporter for the distribution of arsenical species in planta.

Effects of sodium arsenite on the expression of microRNA-191 and tissue inhibitor of metalloproteinase 3 in L-02 cells

Objective To investigate the effects of sodium arsenite（NaAsO2）on the expression of microRNA-191（miR-191）and tissue inhibitor of metalloproteinase 3（TIMP-3）in human normal hepatic cells（L-02 cells）.Methods L-02 cells were exposed to different doses of Na2As O2[0（control group）,5,25,50 and 75μmol/L]

Arsenic uptake and transport of Pteris vittata L.as influenced by phosphate and inorganic arsenic species under sand culture

In order to understand the similarity or difference of inorganic As species uptake and transport related to phosphorus in Ashyperaccumulator, uptake and transport of arsenate （As（V）） and arsenite （As（Ⅲ）） were studied using Pteris vittata L. under sand culture. Higher concentrations of phosphate were found to inhibit accumulation of arsenate and arsenite in the fronds of P. vittata. The reduction in As accumulation was greater in old fronds than in young fronds, and relatively weak in root and rhizome. Moderate increases, from 0.05 to 0.3 mmol/L, in phosphate reduced uptake of As（Ⅲ） more than As（Ⅴ）, while the reverse was observed at high concentrations of phosphate （≥1.0 mmol/L）. Phosphate apparently reduced As transport and the proportion of As accumulated in fronds of P. vittata when As was supplied as As（Ⅴ）. It may in part be due to competition between phosphorus and As（Ⅴ） during transport. In contrast, phosphate had a much smaller effect on As transport when the As was supplied as As（Ⅲ）. Therefore, the results from present experiments indicates that a higher concentration of phosphate suppressed As accumulation and transport in P. vittata, especially in the fronds, when exposed to As（Ⅴ）, but the suppression of phosphate to As transport may be insignificant when P. vittata exposed to As（Ⅲ） under sand culture conditions. The finding will help to understand the interaction of P and As during their uptake process in P. vittata.