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Sample records for enhances arsenic trioxide-induced

  1. Blockage of JNK pathway enhances arsenic trioxide-induced apoptosis in human keratinocytes

    SciTech Connect

    Huang, H.-S.; Liu, Z.-M.; Hong, D.-Y.

    2010-04-15

    Arsenic is well known as a carcinogen predisposing humans to some severe diseases and also as an effective medicine for treating acute promyelocytic leukemia, syphilis, and psoriasis. Multiple active mechanisms, including cell cycle arrest and apoptosis, have been proposed in therapy; however, the opposing effects of arsenic remain controversial. Our previous study found that arsenic trioxide (ATO)-induced activation of p21{sup WAF1/CIP1} (p21) led to A431 cell death through the antagonistic effects of the signaling of ERK1/2 and JNK1. In the current study, the inhibitory effects of JNK1 on ATO-induced p21 expression were explored. Over-expression of JNK1 in A431 cells could inhibit p21 expression, which was associated with HDAC1 and TGIF. Using the GST pull-down assay and fluorescence resonance energy transfer analysis, N-terminal domain (amino acids 1-108) of TGIF, critical to its binding with c-Jun, was found. Using reporter assays, requirement of the C-terminal domain (amino acids 138-272) of TGIF to suppress ATO-induced p21 expression was observed. Thus, the domains of TGIF that carried out its inhibitory effects on p21 were identified. Finally, treatment with JNK inhibitor SP600125 could enhance ATO-induced apoptosis of HaCaT keratinocytes by using flow cytometry.

  2. Heat shock protein inhibitors, 17-DMAG and KNK437, enhance arsenic trioxide-induced mitotic apoptosis

    SciTech Connect

    Wu Yichen; Yen Wenyen; Lee, T.-C. Yih, L.-H.

    2009-04-15

    Arsenic trioxide (ATO) has recently emerged as a promising therapeutic agent in leukemia because of its ability to induce apoptosis. However, there is no sufficient evidence to support its therapeutic use for other types of cancers. In this study, we investigated if, and how, 17-dimethylaminoethylamino-17-demethoxy-geldanamycin (17-DMAG), an antagonist of heat shock protein 90 (HSP90), and KNK437, a HSP synthesis inhibitor, potentiated the cytotoxic effect of ATO. Our results showed that cotreatment with ATO and either 17-DMAG or KNK437 significantly increased ATO-induced cell death and apoptosis. siRNA-mediated attenuation of the expression of the inducible isoform of HSP70 (HSP70i) or HSP90{alpha}/{beta} also enhanced ATO-induced apoptosis. In addition, cotreatment with ATO and 17-DMAG or KNK437 significantly increased ATO-induced mitotic arrest and ATO-induced BUBR1 phosphorylation and PDS1 accumulation. Cotreatment also significantly increased the percentage of mitotic cells with abnormal mitotic spindles and promoted metaphase arrest as compared to ATO treatment alone. These results indicated that 17-DMAG or KNK437 may enhance ATO cytotoxicity by potentiating mitotic arrest and mitotic apoptosis possibly through increased activation of the spindle checkpoint.

  3. Arsenic Trioxide-Induced Mandibular Osteomyelitis.

    PubMed

    Lu, Pei-Chen; Wu, Ju-Hui; Chen, Chun-Ming; Du, Je-Kang

    2015-09-01

    Previously, arsenic was a popular devitalizing agent used to necrotize inflamed dental pulp to lower the pulp sensitivity owing to the unavailability of appropriate anesthesia. However, leakage from the apical foramen, lateral or accessory canals, or cracks in the tooth is common. This can be dangerous because of the reportedly high toxic effects of arsenic in both hard and soft tissues, leading to gingival and osseous necrosis and, consequently, osteomyelitis. Therefore, arsenic can prove fatal for both bones and teeth and is no longer used. We encountered a case involving a 50-year-old man who had developed mandibular osteomyelitis with lower lip paresthesia caused by arsenic trioxide used during endodontic treatment. The patient was treated with appropriate antibiotics, adjunctive hyperbaric oxygen therapy, and adequate surgical debridement. Hyperbaric oxygen therapy can induce neovascularization in necrosed tissues and improve bone and soft tissue healing. At a 4-year follow-up visit, bone healing was observed, with restoration of periodontal health, although the paresthesia had persisted. We describe this case, present a review of the relevant published data, and discuss the possible causes, diagnosis, treatment, and follow-up protocol of mandibular osteomyelitis caused by arsenic trioxide. PMID:25896568

  4. Melatonin enhances arsenic trioxide-induced cell death via sustained upregulation of Redd1 expression in breast cancer cells.

    PubMed

    Yun, Sun-Mi; Woo, Sang Hyeok; Oh, Sang Taek; Hong, Sung-Eun; Choe, Tae-Boo; Ye, Sang-Kyu; Kim, Eun-Kyu; Seong, Min Ki; Kim, Hyun-A; Noh, Woo Chul; Lee, Jin Kyung; Jin, Hyeon-Ok; Lee, Yun-Han; Park, In-Chul

    2016-02-15

    Melatonin is implicated in various physiological functions, including anticancer activity. However, the mechanism(s) of its anticancer activity is not well understood. In the present study, we investigated the combined effects of melatonin and arsenic trioxide (ATO) on cell death in human breast cancer cells. Melatonin enhanced the ATO-induced apoptotic cell death via changes in the protein levels of Survivin, Bcl-2, and Bax, thus affecting cytochrome c release from the mitochondria to the cytosol. Interestingly, we found that the cell death induced by co-treatment with melatonin and ATO was mediated by sustained upregulation of Redd1, which was associated with increased production of reactive oxygen species (ROS). Combined treatment with melatonin and ATO induced the phosphorylation of JNK and p38 MAP kinase downstream from Redd1 expression. Rapamycin and S6K1 siRNA enhanced, while activation of mTORC1 by transfection with TSC2 siRNA suppressed the cell death induced by melatonin and ATO treatment. Taken together, our findings suggest that melatonin enhances ATO-induced apoptotic cell death via sustained upregulation of Redd1 expression and inhibition of mTORC1 upstream of the activation of the p38/JNK pathways in human breast cancer cells. PMID:26607805

  5. Curcumin reduces the expression of survivin, leading to enhancement of arsenic trioxide-induced apoptosis in myelodysplastic syndrome and leukemia stem-like cells.

    PubMed

    Zeng, Yingjian; Weng, Guangyang; Fan, Jiaxin; Li, Zhangqiu; Wu, Jianwei; Li, Yuanming; Zheng, Rong; Xia, Pingfang; Guo, Kunyuan

    2016-09-01

    Low response, treatment-related complications and relapse due to the low sensitivity of myelodysplastic syndrome (MDS) and leukemia stem cells (LSCs) or pre‑LSCs to arsenic trioxide (ATO), represent the main problems following treatment with ATO alone in patients with MDS. To solve these problems, a chemosensitization agent can be applied to increase the susceptibility of these cells to ATO. Curcumin (CUR), which possesses a wide range of anticancer activities, is a commonly used chemosensitization agent for various types of tumors, including hematopoietic malignancies. In the present study, we investigated the cytotoxic effects and potential mechanisms in MDS-SKM-1 and leukemia stem-like KG1a cells treated with CUR and ATO alone or in combination. CUR and ATO exhibited growth inhibition detected by MTT assays and apoptosis analyzed by Annexin V/PI analyses in both SKM-1 and KG1a cells. Apoptosis of SKM-1 and KG1a cells determined by Annexin V/PI was significantly enhanced in the combination groups compared with the groups treated with either agent alone. Further evaluation was performed by western blotting for two hallmark markers of apoptosis, caspase-3 and cleaved-PARP. Co-treatment of the cells with CUR and ATO resulted in significant synergistic effects. In SKM-1 and KG1a cells, 31 and 13 proteins analyzed by protein array assays were modulated, respectively. Notably, survivin protein expression levels were downregulated in both cell lines treated with CUR alone and in combination with ATO, particularly in the latter case. Susceptibility to apoptosis was significantly increased in SKM-1 and KG1a cells treated with siRNA-survivin and ATO. These results suggested that CUR increased the sensitivity of SKM-1 and KG1a cells to ATO by downregulating the expression of survivin. PMID:27430728

  6. Curcumin reduces the expression of survivin, leading to enhancement of arsenic trioxide-induced apoptosis in myelodysplastic syndrome and leukemia stem-like cells

    PubMed Central

    Zeng, Yingjian; Weng, Guangyang; Fan, Jiaxin; Li, Zhangqiu; Wu, Jianwei; Li, Yuanming; Zheng, Rong; Xia, Pingfang; Guo, Kunyuan

    2016-01-01

    Low response, treatment-related complications and relapse due to the low sensitivity of myelodysplastic syndrome (MDS) and leukemia stem cells (LSCs) or pre-LSCs to arsenic trioxide (ATO), represent the main problems following treatment with ATO alone in patients with MDS. To solve these problems, a chemosensitization agent can be applied to increase the susceptibility of these cells to ATO. Curcumin (CUR), which possesses a wide range of anticancer activities, is a commonly used chemosensitization agent for various types of tumors, including hematopoietic malignancies. In the present study, we investigated the cytotoxic effects and potential mechanisms in MDS-SKM-1 and leukemia stem-like KG1a cells treated with CUR and ATO alone or in combination. CUR and ATO exhibited growth inhibition detected by MTT assays and apoptosis analyzed by Annexin V/PI analyses in both SKM-1 and KG1a cells. Apoptosis of SKM-1 and KG1a cells determined by Annexin V/PI was significantly enhanced in the combination groups compared with the groups treated with either agent alone. Further evaluation was performed by western blotting for two hallmark markers of apoptosis, caspase-3 and cleaved-PARP. Co-treatment of the cells with CUR and ATO resulted in significant synergistic effects. In SKM-1 and KG1a cells, 31 and 13 proteins analyzed by protein array assays were modulated, respectively. Notably, survivin protein expression levels were downregulated in both cell lines treated with CUR alone and in combination with ATO, particularly in the latter case. Susceptibility to apoptosis was significantly increased in SKM-1 and KG1a cells treated with siRNA-survivin and ATO. These results suggested that CUR increased the sensitivity of SKM-1 and KG1a cells to ATO by downregulating the expression of survivin. PMID:27430728

  7. Endoplasmic reticulum stress contributes to arsenic trioxide-induced intrinsic apoptosis in human umbilical and bone marrow mesenchymal stem cells.

    PubMed

    King, Yih-An; Chiu, Yu-Jen; Chen, Hao-Ping; Kuo, Daih-Huang; Lu, Chi-Cheng; Yang, Jai-Sing

    2016-03-01

    Arsenic trioxide is an old drug and has been used for a long time in traditional Chinese and Western medicines. However, the cancer treatment of arsenic trioxide has heart and vascular toxicity. The cytotoxic effects of arsenic trioxide and its molecular mechanism in human umbilical mesenchymal stem cells (HUMSC) and human bone marrow-derived mesenchymal stem cells (HMSC-bm) were investigated in this study. Our results showed that arsenic trioxide significantly reduced the viability of HUMSC and HMSC-bm in a concentration- and time-dependent manner. Arsenic trioxide is able to induce apoptotic cell death in HUMSC and HMSC-bm, as shown from the results of morphological examination, flow cytometric analyses, DAPI staining and comet assay. The appearance of arsenic trioxide also led to an increase of intracellular free calcium (Ca(2+) ) concentration and the disruption of mitochondrial membrane potential (ΔΨm). The caspase-9 and caspase-3 activities were time-dependently increased in arsenic trioxide-treated HUMSC and HMSC-bm. In addition, the proteomic analysis and DNA microarray were carried out to investigate the expression level changes of genes and proteins affected by arsenic trioxide treatment in HUMSC. Our results suggest that arsenic trioxide induces a prompt induction of ER stress and mitochondria-modulated apoptosis in HUMSC and HMSC-bm. A framework was proposed for the effect of arsenic trioxide cytotoxicity by targeting ER stress. PMID:25258189

  8. Resveratrol protects against arsenic trioxide-induced nephrotoxicity by facilitating arsenic metabolism and decreasing oxidative stress.

    PubMed

    Yu, Meiling; Xue, Jiangdong; Li, Yijing; Zhang, Weiqian; Ma, Dexing; Liu, Lian; Zhang, Zhigang

    2013-06-01

    Arsenic trioxide (As(2)O(3)) is an environmental toxicant and a potent antineoplastic agent. Exposure to arsenic causes renal cancer. Resveratrol is a well-known polyphenolic compound that is reported to reduce As(2)O(3)-induced cardiotoxicity. The present study aimed to investigate the effect of resveratrol on As(2)O(3)-induced nephrotoxicity and arsenic metabolism. Chinese Dragon-Li cats were injected with 1 mg/kg As(2)O(3) on alternate days; resveratrol (3 mg/kg) was administered via the forearm vein 1 h before the As(2)O(3) treatment. On the sixth day, the cats were killed to determine the histological renal damage, renal function, the accumulation of arsenic, and antioxidant activities in the kidney. Urine samples were taken for arsenic speciation. In the resveratrol + As(2)O(3)-treated group, activities of glutathione peroxidase, catalase, and superoxide dismutase, the ratio of reduced glutathione to oxidized glutathione, the total arsenic concentrations, and the percentage of methylated arsenic in urine were significantly increased. The concentrations of renal malondialdehyde, reactive oxygen species, 8-hydroxydeoxyguanosine, serum creatinine, blood urea nitrogen, and renal arsenic accumulation were significantly decreased and reduced renal morphologic injury was observed compared with the As(2)O(3)-treated group. These results demonstrate that resveratrol could significantly scavenge reactive oxygen species, inhibit As(2)O(3)-induced oxidative damage, and significantly attenuate the accumulation of arsenic in renal tissues by facilitating As(2)O(3) metabolism. These data suggest that use of resveratrol as postremission therapy for acute promyelocytic leukemia as well as adjunctive therapy in patients with exposure to arsenic may decrease arsenic nephrotoxicity. PMID:23471352

  9. Role of Signal Regulatory Protein α in Arsenic Trioxide-induced Promyelocytic Leukemia Cell Apoptosis.

    PubMed

    Pan, Chaoyun; Zhu, Dihan; Zhuo, Jianjiang; Li, Limin; Wang, Dong; Zhang, Chen-Yu; Liu, Yuan; Zen, Ke

    2016-01-01

    Signal regulatory protein α (SIRPα) has been shown to operate as a negative regulator in cancer cell survival. The mechanism underneath such function, however, remains poorly defined. In the present study, we demonstrate that overexpression of SIRPα in acute promyelocytic leukemia (APL) cells results in apoptosis possibly via inhibiting the β-catenin signaling pathway and upregulating Foxo3a. Pharmacological activation of β-catenin signal pathway attenuates apoptosis caused by SIRPα. Interestingly, we also find that the pro-apoptotic effect of SIRPα plays an important role in arsenic trioxide (ATO)-induced apoptosis in APL cells. ATO treatment induces the SIRPα protein expression in APL cells and abrogation of SIRPα induction by lentivirus-mediated SIRPα shRNA significantly reduces the ATO-induced apoptosis. Mechanistic study further shows that induction of SIRPα protein in APL cells by ATO is mediated through suppression of c-Myc, resulting in reduction of three SIRPα-targeting microRNAs: miR-17, miR-20a and miR-106a. In summary, our results demonstrate that SIRPα inhibits tumor cell survival and significantly contributes to ATO-induced APL cell apoptosis. PMID:27010069

  10. Role of Signal Regulatory Protein α in Arsenic Trioxide-induced Promyelocytic Leukemia Cell Apoptosis

    PubMed Central

    Pan, Chaoyun; Zhu, Dihan; Zhuo, Jianjiang; Li, Limin; Wang, Dong; Zhang, Chen-Yu; Liu, Yuan; Zen, Ke

    2016-01-01

    Signal regulatory protein α (SIRPα) has been shown to operate as a negative regulator in cancer cell survival. The mechanism underneath such function, however, remains poorly defined. In the present study, we demonstrate that overexpression of SIRPα in acute promyelocytic leukemia (APL) cells results in apoptosis possibly via inhibiting the β-catenin signaling pathway and upregulating Foxo3a. Pharmacological activation of β-catenin signal pathway attenuates apoptosis caused by SIRPα. Interestingly, we also find that the pro-apoptotic effect of SIRPα plays an important role in arsenic trioxide (ATO)-induced apoptosis in APL cells. ATO treatment induces the SIRPα protein expression in APL cells and abrogation of SIRPα induction by lentivirus-mediated SIRPα shRNA significantly reduces the ATO-induced apoptosis. Mechanistic study further shows that induction of SIRPα protein in APL cells by ATO is mediated through suppression of c-Myc, resulting in reduction of three SIRPα-targeting microRNAs: miR-17, miR-20a and miR-106a. In summary, our results demonstrate that SIRPα inhibits tumor cell survival and significantly contributes to ATO-induced APL cell apoptosis. PMID:27010069

  11. Arsenic Trioxide Induces Apoptosis in Human Platelets via C-Jun NH2-Terminal Kinase Activation

    PubMed Central

    Wu, Yicun; Dai, Jin; Zhang, Weilin; Yan, Rong; Zhang, Yiwen; Ruan, Changgeng; Dai, Kesheng

    2014-01-01

    Arsenic trioxide (ATO), one of the oldest drugs in both Western and traditional Chinese medicine, has become an effective anticancer drug, especially in the treatment of acute promyelocytic leukemia (APL). However, thrombocytopenia occurred in most of ATO-treated patients with APL or other malignant diseases, and the pathogenesis remains unclear. Here we show that ATO dose-dependently induces depolarization of mitochondrial inner transmembrane potential (ΔΨm), up-regulation of Bax and down-regulation of Bcl-2 and Bcl-XL, caspase-3 activation, and phosphotidylserine (PS) exposure in platelets. ATO did not induce surface expression of P-selectin and PAC-1 binding, whereas, obviously reduced collagen, ADP, and thrombin induced platelet aggregation. ATO dose-dependently induced c-Jun NH2-terminal kinase (JNK) activation, and JNK specific inhibitor dicumarol obviously reduced ATO-induced ΔΨm depolarization in platelets. Clinical therapeutic dosage of ATO was intraperitoneally injected into C57 mice, and the numbers of circulating platelets were significantly reduced after five days of continuous injection. The data demonstrate that ATO induces caspase-dependent apoptosis via JNK activation in platelets. ATO does not incur platelet activation, whereas, it not only impairs platelet function but also reduces circulating platelets in vivo, suggesting the possible pathogenesis of thrombocytopenia in patients treated with ATO. PMID:24466103

  12. Arsenic trioxide induces apoptosis in human platelets via C-Jun NH2-terminal kinase activation.

    PubMed

    Wu, Yicun; Dai, Jin; Zhang, Weilin; Yan, Rong; Zhang, Yiwen; Ruan, Changgeng; Dai, Kesheng

    2014-01-01

    Arsenic trioxide (ATO), one of the oldest drugs in both Western and traditional Chinese medicine, has become an effective anticancer drug, especially in the treatment of acute promyelocytic leukemia (APL). However, thrombocytopenia occurred in most of ATO-treated patients with APL or other malignant diseases, and the pathogenesis remains unclear. Here we show that ATO dose-dependently induces depolarization of mitochondrial inner transmembrane potential (ΔΨm), up-regulation of Bax and down-regulation of Bcl-2 and Bcl-XL, caspase-3 activation, and phosphotidylserine (PS) exposure in platelets. ATO did not induce surface expression of P-selectin and PAC-1 binding, whereas, obviously reduced collagen, ADP, and thrombin induced platelet aggregation. ATO dose-dependently induced c-Jun NH2-terminal kinase (JNK) activation, and JNK specific inhibitor dicumarol obviously reduced ATO-induced ΔΨm depolarization in platelets. Clinical therapeutic dosage of ATO was intraperitoneally injected into C57 mice, and the numbers of circulating platelets were significantly reduced after five days of continuous injection. The data demonstrate that ATO induces caspase-dependent apoptosis via JNK activation in platelets. ATO does not incur platelet activation, whereas, it not only impairs platelet function but also reduces circulating platelets in vivo, suggesting the possible pathogenesis of thrombocytopenia in patients treated with ATO. PMID:24466103

  13. Requirement of PML SUMO interacting motif for RNF4- or arsenic trioxide-induced degradation of nuclear PML isoforms.

    PubMed

    Maroui, Mohamed Ali; Kheddache-Atmane, Sabrina; El Asmi, Faten; Dianoux, Laurent; Aubry, Muriel; Chelbi-Alix, Mounira K

    2012-01-01

    PML, the organizer of nuclear bodies (NBs), is expressed in several isoforms designated PMLI to VII which differ in their C-terminal region due to alternative splicing of a single gene. This variability is important for the function of the different PML isoforms. PML NB formation requires the covalent linkage of SUMO to PML. Arsenic trioxide (As₂O₃) enhances PML SUMOylation leading to an increase in PML NB size and promotes its interaction with RNF4, a poly-SUMO-dependent ubiquitin E3 ligase responsible for proteasome-mediated PML degradation. Furthermore, the presence of a bona fide SUMO Interacting Motif (SIM) within the C-terminal region of PML seems to be required for recruitment of other SUMOylated proteins within PML NBs. This motif is present in all PML isoforms, except in the nuclear PMLVI and in the cytoplasmic PMLVII. Using a bioluminescence resonance energy transfer (BRET) assay in living cells, we found that As₂O₃ enhanced the SUMOylation and interaction with RNF4 of nuclear PML isoforms (I to VI). In addition, among the nuclear PML isoforms, only the one lacking the SIM sequence, PMLVI, was resistant to As₂O₃-induced PML degradation. Similarly, mutation of the SIM in PMLIII abrogated its sensitivity to As₂O₃-induced degradation. PMLVI and PMLIII-SIM mutant still interacted with RNF4. However, their resistance to the degradation process was due to their inability to be polyubiquitinated and to recruit efficiently the 20S core and the β regulatory subunit of the 11S complex of the proteasome in PML NBs. Such resistance of PMLVI to As₂O₃-induced degradation was alleviated by overexpression of RNF4. Our results demonstrate that the SIM of PML is dispensable for PML SUMOylation and interaction with RNF4 but is required for efficient PML ubiquitination, recruitment of proteasome components within NBs and proteasome-dependent degradation of PML in response to As₂O₃. PMID:23028697

  14. Requirement of PML SUMO Interacting Motif for RNF4- or Arsenic Trioxide-Induced Degradation of Nuclear PML Isoforms

    PubMed Central

    El Asmi, Faten; Dianoux, Laurent; Aubry, Muriel; Chelbi-Alix, Mounira K.

    2012-01-01

    PML, the organizer of nuclear bodies (NBs), is expressed in several isoforms designated PMLI to VII which differ in their C-terminal region due to alternative splicing of a single gene. This variability is important for the function of the different PML isoforms. PML NB formation requires the covalent linkage of SUMO to PML. Arsenic trioxide (As2O3) enhances PML SUMOylation leading to an increase in PML NB size and promotes its interaction with RNF4, a poly-SUMO-dependent ubiquitin E3 ligase responsible for proteasome-mediated PML degradation. Furthermore, the presence of a bona fide SUMO Interacting Motif (SIM) within the C-terminal region of PML seems to be required for recruitment of other SUMOylated proteins within PML NBs. This motif is present in all PML isoforms, except in the nuclear PMLVI and in the cytoplasmic PMLVII. Using a bioluminescence resonance energy transfer (BRET) assay in living cells, we found that As2O3 enhanced the SUMOylation and interaction with RNF4 of nuclear PML isoforms (I to VI). In addition, among the nuclear PML isoforms, only the one lacking the SIM sequence, PMLVI, was resistant to As2O3-induced PML degradation. Similarly, mutation of the SIM in PMLIII abrogated its sensitivity to As2O3-induced degradation. PMLVI and PMLIII-SIM mutant still interacted with RNF4. However, their resistance to the degradation process was due to their inability to be polyubiquitinated and to recruit efficiently the 20S core and the β regulatory subunit of the 11S complex of the proteasome in PML NBs. Such resistance of PMLVI to As2O3-induced degradation was alleviated by overexpression of RNF4. Our results demonstrate that the SIM of PML is dispensable for PML SUMOylation and interaction with RNF4 but is required for efficient PML ubiquitination, recruitment of proteasome components within NBs and proteasome-dependent degradation of PML in response to As2O3. PMID:23028697

  15. Arsenic trioxide induces oxidative stress, DNA damage, and mitochondrial pathway of apoptosis in human leukemia (HL-60) cells

    PubMed Central

    2014-01-01

    Background Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML), which accounts for approximately 10% of all acute myloid leukemia cases. It is a blood cancer that is formed by chromosomal mutation. Each year in the United States, APL affects about 1,500 patients of all age groups and causes approximately 1.2% of cancer deaths. Arsenic trioxide (ATO) has been used successfully for treatment of APL patients, and both induction and consolidated therapy have resulted in complete remission. Recently published studies from our laboratory have demonstrated that ATO pharmacology as an anti-leukemic drug is associated with cytotoxic and genotoxic effects in leukemia cells. Methods In the present study, we further investigated the detailed molecular mechanism of ATO-mediated intrinsic pathway of apoptosis; using HL-60 cells as a test model. Oxidative stress was assessed by spectrophotometric measurements of MDA and GSH levels while genotoxicity was determined by single cell gel electrophoresis (Comet assay). Apoptosis pathway was analyzed by Western blot analysis of Bax, Bcl2 and caspase 3 expression, as well as immunocytochemistry and confocal imaging of Bax and Cyt c translocation and mitochondrial membrane potential depolarization. Results ATO significantly (p < 0.05) induces oxidative stress, DNA damage, and caspase 3 activityin HL-60 cells in a dose-dependent manner. It also activated the intrinsic pathway of apoptosis by significantly modulating (p < 0.05) the expression and translocation of apoptotic molecules and decreasing the mitochondrial membrane potential in leukemia cells. Conclusion Taken together, our research demonstrated that ATO induces mitochondrial pathway of apoptosis in HL-60 cells. This apoptotic signaling is modulated via oxidative stress, DNA damage, and change in mitochondrial membrane potential, translocation and upregulation of apoptotic proteins leading programmed cell death. PMID:24887205

  16. Down-regulation of Mcl-1 through GSK-3β activation contributes to arsenic trioxide-induced apoptosis in acute myeloid leukemia cells

    PubMed Central

    Wang, Rui; Xia, Lijuan; Gabrilove, Janice; Waxman, Samuel; Jing, Yongkui

    2012-01-01

    Arsenic trioxide (ATO) induces disease remission in acute promyelocytic leukemia (APL) patients, but not in non-APL acute myeloid leukemia (AML) patients. ATO at therapeutic concentrations (1-2 μM) induce APL NB4, but not non-APL HL-60, cells to undergo apoptosis through the mitochondrial pathway. The role of antiapoptotic protein Mcl-1 in ATO-induced apoptosis was determined. The levels of Mcl-1 were decreased in NB4, but not in HL-60, cells after ATO treatment through proteasomal degradation. Both GSK3β inhibitor SB216763 and siRNA blocked ATO-induced Mcl-1 reduction as well as attenuated ATO-induced apoptosis in NB4 cells. Silencing Mcl-1 sensitized HL-60 cells to ATO-induced apoptosis. Both ERK and AKT inhibitors decreased Mcl-1 levels and enhanced ATO-induced apoptosis in HL-60 cells. Sorafenib, a Raf inhibitor, activated GSK3β by inhibiting its phosphorylation, decreased Mcl-1 levels, and decreased intracellular glutathione levels in HL-60 cells. Sorafenib plus ATO augmented ROS production and apoptosis induction in HL-60 cells and in primary AML cells. These results indicate that ATO induces Mcl-1 degradation through activation of GSK3β in APL cells and provide a rationale for utilizing ATO in combination with sorafenib for the treatment of non-APL AML patients. PMID:22751450

  17. TG-interacting factor transcriptionally induced by AKT/FOXO3A is a negative regulator that antagonizes arsenic trioxide-induced cancer cell apoptosis

    SciTech Connect

    Liu, Zi-Miao; Tseng, Hong-Yu; Cheng, Ya-Ling; Yeh, Bi-Wen; Wu, Wen-Jeng; Huang, Huei-Sheng

    2015-05-15

    Arsenic trioxide (ATO) is a multi-target drug approved by the Food and Drug Administration as the first-line chemotherapeutic agent for the treatment of acute promyelocytic leukemia. In addition, several clinical trials are being conducted with arsenic-based drugs for the treatment of other hematological malignancies and solid tumors. However, ATO's modest clinical efficacy on some cancers, and potential toxic effects on humans have been reported. Determining how best to reduce these adverse effects while increasing its therapeutic efficacy is obviously a critical issue. Previously, we demonstrated that the JNK-induced complex formation of phosphorylated c-Jun and TG-interacting factor (TGIF) antagonizes ERK-induced cyclin-dependent kinase inhibitor CDKN1A (p21{sup WAF1/CIP1}) expression and resultant apoptosis in response to ATO in A431 cells. Surprisingly, at low-concentrations (0.1–0.2 μM), ATO increased cellular proliferation, migration and invasion, involving TGIF expression, however, at high-concentrations (5–20 μM), ATO induced cell apoptosis. Using a promoter analysis, TGIF was transcriptionally regulated by ATO at the FOXO3A binding site (− 1486 to − 1479 bp) via the c-Src/EGFR/AKT pathway. Stable overexpression of TGIF promoted advancing the cell cycle into the S phase, and attenuated 20 μM ATO-induced apoptosis. Furthermore, blockage of the AKT pathway enhanced ATO-induced CDKN1A expression and resultant apoptosis in cancer cells, but overexpression of AKT1 inhibited CDKN1A expression. Therefore, we suggest that TGIF is transcriptionally regulated by the c-Src/EGFR/AKT pathway, which plays a role as a negative regulator in antagonizing ATO-induced CDKN1A expression and resultant apoptosis. Suppression of these antagonistic effects might be a promising therapeutic strategy toward improving clinical efficacy of ATO. - Highlights: • ATO-induced biphasic survival responses of cancer cells depend on low- or high-concentrations. • TGIF mediates

  18. PCGF2 negatively regulates arsenic trioxide-induced PML-RARA protein degradation via UBE2I inhibition in NB4 cells.

    PubMed

    Jo, Sungsin; Lee, Young Lim; Kim, Sojin; Lee, Hongki; Chung, Heekyoung

    2016-07-01

    Arsenic trioxide (ATO) is a therapeutic agent for acute promyelocytic leukemia (APL) which induces PML-RARA protein degradation via enhanced UBE2I-mediated sumoylation. PCGF2, a Polycomb group protein, has been suggested as an anti-SUMO E3 protein by inhibiting the sumoylation of UBE2I substrates, HSF2 and RANGAP1, via direct interaction. Thus, we hypothesized that PCGF2 might play a role in ATO-induced PML-RARA degradation by interacting with UBE2I. PCGF2 protein was down-regulated upon ATO treatment in human APL cell line, NB4. Knockdown of PCGF2 in NB4 cells, in the absence of ATO treatment, was sufficient to induce sumoylation-, ubiquitylation- and PML nuclear body-mediated degradation of PML-RARA protein. Moreover, overexpression of PCGF2 protected ATO-mediated degradation of ectopic and endogenous PML-RARA in 293T and NB4 cells, respectively. In 293T cells, UBE2I-mediated PML-RARA degradation was reduced upon PCGF2 co-expression. In addition, UBE2I-mediated sumoylation of PML-RARA was reduced upon PCGF2 co-expression and PCGF2-UBE2I interaction was confirmed by co-immunoprecipitation. Likewise, endogenous PCGF2-UBE2I interaction was detected by co-immunoprecipitation and immunofluorescence assays in NB4 cells. Intriguingly, upon ATO-treatment, such interaction was disrupted and UBE2I was co-immunoprecipitated or co-localized with its SUMO substrate, PML-RARA. Taken together, our results suggested a novel role of PCGF2 in ATO-mediated degradation of PML-RARA that PCGF2 might act as a negative regulator of UBE2I via direct interaction. PMID:27030546

  19. Arsenic Trioxide Induces Apoptosis and Incapacitates Proliferation and Invasive Properties of U87MG Glioblastoma Cells through a Possible NF-κB-Mediated Mechanism.

    PubMed

    Ghaffari, Seyed H; Yousefi, Meysam; Dizaji, Majid Zaki; Momeny, Majid; Bashash, Davood; Zekri, Ali; Alimoghaddam, Kamran; Ghavamzadeh, Ardeshir

    2016-01-01

    Identification of novel therapeutics in glioblastoma remains crucial due to the devastating and infiltrative capacity of this malignancy. The current study was aimed to appraise effect of arsenic trioxide (ATO) in U87MG cells. The results demonstrated that ATO induced apoptosis and impeded proliferation of U87MG cells in a dosedependent manner and also inhibited classical NF-κB signaling pathway. ATO further upregulated expression of Bax as an important proapoptotic target of NF-κB and also inhibited mRNA expression of survivin, c-Myc and hTERT and suppressed telomerase activity. Moreover, ATO significantly increased adhesion of U87MG cells and also diminished transcription of NF-κB down-stream targets involved in cell migration and invasion, including cathepsin B, uPA, MMP-2, MMP-9 and MMP-14 and suppressed proteolytic activity of cathepsin B, MMP-2 and MMP-9, demonstrating a possible mechanism of ATO effect on a well-known signaling in glioblastoma dissemination. Taken together, here we suggest that ATO inhibits survival and invasion of U87MG cells possibly through NF-κB-mediated inhibition of survivin and telomerase activity and NF-κB-dependent suppression of cathepsin B, MMP-2 and MMP-9. PMID:27039805

  20. Enhanced coagulation for arsenic removal

    SciTech Connect

    Cheng, R.C.; Liang, S.; Wang, H.C.; Beuhler, M.D. )

    1994-09-01

    The possible use of enhanced coagulation for arsenic removal was examined at the facilities of a California utility in 1992 and 1993. The tests were conducted at bench, pilot, and demonstration scales, with two source waters. Alum and ferric chloride, with cationic polymer, were investigated at various influence arsenic concentrations. The investigators concluded that for the source waters tested, enhanced coagulation could be effective for arsenic removal and that less ferric chloride than alum, on a weight basis, is needed to achieve the same removal.

  1. Arsenic

    MedlinePlus

    Arsenic is a natural element found in soil and minerals. Arsenic compounds are used to preserve wood, as pesticides, and in some industries. Arsenic can get into air, water, and the ground from wind- ...

  2. Arsenic

    MedlinePlus

    ... and minerals. Arsenic compounds are used to preserve wood, as pesticides, and in some industries. Arsenic can ... Breathing sawdust or burning smoke from arsenic-treated wood Living in an area with high levels of ...

  3. FOLATE DEFICIENCY ENHANCES ARSENIC-INDUCED GENOTOXICITY IN MICE

    EPA Science Inventory

    Folate deficiency increases background levels of DNA damage and can enhance the mutagenicity of chemical agents. Duplicate experiments were performed to investigate the effect of dietary folate deficiency on arsenic induction of micronuclei (MN) in peripheral blood cells. Male C5...

  4. Arsenic

    MedlinePlus

    ... mainly found in its less toxic organic form. Industrial processes Arsenic is used industrially as an alloying ... are also required to reduce occupational exposure from industrial processes. Education and community engagement are key factors ...

  5. Chronic subhepatotoxic exposure to arsenic enhances hepatic injury caused by high fat diet in mice

    SciTech Connect

    Tan, Min; Schmidt, Robin H.; Beier, Juliane I.; Watson, Walter H.; Zhong, Hai; States, J. Christopher; Arteel, Gavin E.

    2011-12-15

    Arsenic is a ubiquitous contaminant in drinking water. Whereas arsenic can be directly hepatotoxic, the concentrations/doses required are generally higher than present in the US water supply. However, physiological/biochemical changes that are alone pathologically inert can enhance the hepatotoxic response to a subsequent stimulus. Such a '2-hit' paradigm is best exemplified in chronic fatty liver diseases. Here, the hypothesis that low arsenic exposure sensitizes liver to hepatotoxicity in a mouse model of non-alcoholic fatty liver disease was tested. Accordingly, male C57Bl/6J mice were exposed to low fat diet (LFD; 13% calories as fat) or high fat diet (HFD; 42% calories as fat) and tap water or arsenic (4.9 ppm as sodium arsenite) for ten weeks. Biochemical and histologic indices of liver damage were determined. High fat diet ({+-} arsenic) significantly increased body weight gain in mice compared with low-fat controls. HFD significantly increased liver to body weight ratios; this variable was unaffected by arsenic exposure. HFD caused steatohepatitis, as indicated by histological assessment and by increases in plasma ALT and AST. Although arsenic exposure had no effect on indices of liver damage in LFD-fed animals, it significantly increased the liver damage caused by HFD. This effect of arsenic correlated with enhanced inflammation and fibrin extracellular matrix (ECM) deposition. These data indicate that subhepatotoxic arsenic exposure enhances the toxicity of HFD. These results also suggest that arsenic exposure might be a risk factor for the development of fatty liver disease in human populations. -- Highlights: Black-Right-Pointing-Pointer Characterizes a mouse model of arsenic enhanced NAFLD. Black-Right-Pointing-Pointer Arsenic synergistically enhances experimental fatty liver disease at concentrations that cause no overt hepatotoxicity alone. Black-Right-Pointing-Pointer This effect is associated with increased inflammation.

  6. Both Phosphorus Fertilizers and Indigenous Bacteria Enhance Arsenic Release into Groundwater in Arsenic-Contaminated Aquifers.

    PubMed

    Lin, Tzu-Yu; Wei, Chia-Cheng; Huang, Chi-Wei; Chang, Chun-Han; Hsu, Fu-Lan; Liao, Vivian Hsiu-Chuan

    2016-03-23

    Arsenic (As) is a human carcinogen, and arsenic contamination in groundwater is a worldwide public health concern. Arsenic-affected areas are found in many places but are reported mostly in agricultural farmlands, yet the interaction of fertilizers, microorganisms, and arsenic mobilization in arsenic-contaminated aquifers remains uncharacterized. This study investigates the effects of fertilizers and bacteria on the mobilization of arsenic in two arsenic-contaminated aquifers. We performed microcosm experiments using arsenic-contaminated sediments and amended with inorganic nitrogenous or phosphorus fertilizers for 1 and 4 months under aerobic and anaerobic conditions. The results show that microcosms amended with 100 mg/L phosphorus fertilizers (dipotassium phosphate), but not nitrogenous fertilizers (ammonium sulfate), significantly increase aqueous As(III) release in arsenic-contaminated sediments under anaerobic condition. We also show that concentrations of iron, manganese, potassium, sodium, calcium, and magnesium are increased in the aqueous phase and that the addition of dipotassium phosphate causes a further increase in aqueous iron, potassium, and sodium, suggesting that multiple metal elements may take part in the arsenic release process. Furthermore, microbial analysis indicates that the dominant microbial phylum is shifted from α-proteobacteria to β- and γ-proteobacteria when the As(III) is increased and phosphate is added in the aquifer. Our results provide evidence that both phosphorus fertilizers and microorganisms can mediate the release of arsenic to groundwater in arsenic-contaminated sediments under anaerobic condition. Our study suggests that agricultural activity such as the use of fertilizers and monitoring phosphate concentration in groundwater should be taken into consideration for the management of arsenic in groundwater. PMID:26937943

  7. Tetrandrine enhances the anticancer effects of arsenic trioxide in vitro.

    PubMed

    Chen, Youran; Li, Peichun; Yang, Shen; Tong, Nannan; Zhang, Jie; Zhao, Xiaoyan

    2014-05-01

    Arsenic trioxide (As2O3), an effective agent to treat leukemia and other solid tumors, is largely limited by its toxicity. QT prolongation, torsades de pointes and sudden death have been implicated in the cardiotoxicity of As2O3. The present study was designed to assess whether the combination of As2O3 and tetrandrine could generate a more powerful anti-cancer effect. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed for detecting the proliferation of HepG2 and A549 cells treated with tetrandrine and As2O3. Fluorescent microscopy measurements and flow cytometry were carried out to evaluate the apoptosis in HepG2 cells. The cell cycle arrest of HepG2 cells was also determined by flow cytometry. The cell proliferation assay in HepG2 and A549 cells indicated that tetrandrine significantly enhanced the inhibit effect of As2O3. In addition, the following Isobolograms further demonstrated that combining As2O3 with tetrandrine generated synergism action. Tetrandrine also enhanced the apoptosis, necrosis and cell cycle arrest in As2O3-treated HepG2 cells. Our present study showed that tetrandrine can dramatically enhance the anti- cancer effect induced by As2O3. Combining As2O3 with tetrandrine would be a novel strategy to treat cancer in clinical practice. PMID:24548979

  8. Subhepatotoxic exposure to arsenic enhances lipopolysaccharide-induced liver injury in mice

    PubMed Central

    Arteel, Gavin E.; Guo, Luping; Schlierf, Thomas; Beier, Juliane I; Kaiser, J. Phillip; Chen, Theresa S; Liu, Marsha; Conklin, Daniel P.; Miller, Heather L.; von Montfort, Claudia; States, J. Christopher

    2008-01-01

    Exposure to arsenic via drinking water is a serious health concern in the US. Whereas studies have identified arsenic alone as an independent risk factor for liver disease, concentrations of arsenic required to damage this organ are generally higher than found in the US water supply. The purpose of the current study was to test the hypothesis that arsenic (at subhepatotoxic doses) may also sensitize the liver to a second hepatotoxin. To test this hypothesis, the effect of chronic exposure to arsenic on liver damage caused by acute lipopolysaccharide (LPS) was determined in mice. Male C57Bl/6J mice (4-6 weeks) were exposed to arsenic (49 ppm as sodium arsenite in drinking water). After 7 months of exposure, animals were injected with LPS (10 mg/kg i.p.) and sacrificed 24 h later. Arsenic alone caused no overt hepatotoxicity, as determined by plasma enzymes and histology. In contrast, arsenic exposure dramatically enhanced liver damage caused by LPS, increasing the number and size of necroinflammatory foci. This effect of arsenic was coupled with increases in indices of oxidative stress (4-HNE adducts, depletion of GSH and methionine pools). The number of apoptotic (TUNEL) hepatocytes was similar in the LPS and arsenic/LPS groups. In contrast, arsenic pre-exposure blunted the increase in proliferating (PCNA) hepatocytes caused by LPS; this change in the balance between cell death and proliferation was coupled with a robust loss of liver weight in the arsenic/LPS compared to the LPS alone group. The impairment of proliferation after LPS caused by arsenic was also coupled with alterations in the expression of key mediators of cell cycle progression (p27, p21, CDK6 and Cyclin D1). Taken together, these results suggest that arsenic, at doses that are not overtly hepatotoxic per se, significantly enhances LPS-induced liver injury. These results further suggest that arsenic levels in the drinking water may be a risk modifier for the development of chronic liver diseases

  9. CASE STUDY: SITE CONCEPTUAL MODEL FOR ENHANCED MNA OF ARSENIC

    EPA Science Inventory

    Field investigations have been conducted to understand the fate of arsenic in contaminated ground water during discharge into the Halls Brook Holding Area (HBHA) Pond at the Industri-Plex Superfund Site in Massachusetts. The ground water plume contains elevated levels of arsenic...

  10. Arsenic-induced cell proliferation is associated with enhanced ROS generation, Erk signaling and CyclinA expression.

    PubMed

    Chowdhury, Rajdeep; Chatterjee, Raghunath; Giri, Ashok K; Mandal, Chitra; Chaudhuri, Keya

    2010-10-01

    Arsenic is a well-established human carcinogen; however molecular mechanisms to arsenic-induced carcinogenesis are complex and elusive. The present study identifies a potential biomarker of arsenic exposure, and redefines arsenic-induced signaling in stimulation of cell proliferation. The effect of arsenic exposure on gene expression was evaluated in PBMC of arsenic-exposed individuals selected from a severely affected district of West Bengal, India. A novel, un-documented biomarker of arsenic exposure, CyclinA was identified by microarray analysis from the study. Non-transformed cell lines HaCat and Int407 when exposed to clinically achievable arsenic concentration showed significant increase of CyclinA substantiating the clinical data. An associated increase in S phase population of cells in cell cycle, indicative of enhanced proliferation was also noticed. On further investigation of the pathway to arsenic-induced proliferation, we observed that arsenic resulted: ROS generation; activated Erk signaling; stimulated AP-1 activity, including immediate early genes, c-Jun and c-Fos. N-Acetyl-l-cysteine, a ROS quencher, blocked the arsenic-induced effects. Our study underlines a previously undefined mechanism by which arsenic imparts its toxicity and results in uncontrolled cell proliferation. PMID:20654705

  11. DIETARY FOLATE DEFICIENCY ENHANCES ARSENIC-INDUCED MICRONUCLEUS FORMATION IN MICE

    EPA Science Inventory


    Dietary folate deficiency enhances arsenic-induced micronucleus formation in mice.

    Folate deficiency increases background levels ofDNA damage and can enhance the mutagenicity of chemical agents. Duplicate experiments were performed to investigate the effect of dietary...

  12. Enhanced coagulation for satisfying the arsenic maximum contaminant level under variable and uncertain conditions.

    PubMed

    Boccelli, Dominic L; Small, Mitchell J; Dzombak, David A

    2005-09-01

    This study evaluated the effects of influent variability and model parameter uncertainty when utilizing enhanced coagulation modification to bring existing treatment plants into compliance with a stricter arsenic regulation. Enhanced coagulation modification options include: (1) increased ferric chloride dose, (2) addition of an acid dose, and (3) a combination of the individual options. Arsenic removal is described by adsorption to hydrous ferric oxide with a surface complexation model and subsequent removal through sedimentation and filtration. The least-cost modification for reliably satisfying the arsenic regulation is determined using an optimization algorithm that explicitly includes variability and uncertainty. The ferric chloride only modification is always the least-cost treatment modification. The ferric chloride and acid modification could be the least-cost option when considering waste handling processes due to a tradeoff between modification cost and sludge production. By inclusion of variability and uncertainty, the relative importance of individual parameter distributions for determining whether the arsenic regulation is reliably satisfied is assessed. Influent arsenic concentration variability is always critical, while variability in the influent pH and sulfate concentrations and uncertainty in the filter removal efficiency and equilibrium adsorption constant for the triple bond Fe(s)OHCa2+ surface species are critical or important, depending on influent conditions. PMID:16190205

  13. Mthfr gene ablation enhances susceptibility to arsenic prenatal toxicity

    SciTech Connect

    Wlodarczyk, Bogdan J. Zhu, Huiping; Finnell, Richard H.

    2014-02-15

    Background: In utero exposure to arsenic is known to adversely affect reproductive outcomes. Evidence of arsenic teratogenicity varies widely and depends on individual genotypic differences in sensitivity to As. In this study, we investigated the potential interaction between 5,10-methylenetetrahydrofolate reductase (Mthfr) genotype and arsenic embryotoxicity using the Mthfr knockout mouse model. Methods: Pregnant dams were treated with sodium arsenate, and reproductive outcomes including: implantation, resorption, congenital malformation and fetal birth weight were recorded at E18.5. Results: When the dams in Mthfr{sup +/−} × Mthfr{sup +/−} matings were treated with 7.2 mg/kg As, the resorption rate increased to 43.4%, from a background frequency of 7.2%. The As treatment also induced external malformations (40.9%) and significantly lowered the average fetal birth weight among fetuses, without any obvious toxic effect on the dam. When comparing the pregnancy outcomes resulting from different mating scenarios (Mthfr{sup +/+} × Mthfr{sup +/−}, Mthfr{sup +/−} × Mthfr{sup +/−} and Mthfr{sup −/−} × {sup Mthfr+/−}) and arsenic exposure; the resorption rate showed a linear relationship with the number of null alleles (0, 1 or 2) in the Mthfr dams. Fetuses from nullizygous dams had the highest rate of external malformations (43%) and lowest average birth weight. When comparing the outcomes of reciprocal matings (nullizygote × wild-type versus wild-type × nullizygote) after As treatment, the null dams showed significantly higher rates of resorptions and malformations, along with lower fetal birth weights. Conclusions: Maternal genotype contributes to the sensitivity of As embryotoxicity in the Mthfr mouse model. The fetal genotype, however, does not appear to affect the reproductive outcome after in utero As exposure. - Highlights: • An interaction between Mthfr genotype and arsenic embryotoxicity is presented. • Maternal Mthfr genotype

  14. DIETARY FOLATE DEFICIENCY ENHANCES INDUCTION OF MICRONUCLEI BY ARSENIC IN MICE

    EPA Science Inventory

    Folate deficiency increases background levels of DNA damage and can enhance the genotoxicity of chemical agents. Arsenic, a known human carcinogen present in drinking water supplies around the world, induces chromosomal and DNA damage. The effect of dietary folate deficiency on...

  15. Small System Use of a Solid Arsenic Oxidizing Media in Place of Chemical Oxidation to Enhance Arsenic Removals

    EPA Science Inventory

    As part of the USEPA Arsenic Demonstration Program, an arsenic removal adsorptive media treatment system (10 gpm) was installed at Head Start School in Buckeye Lake, Ohio on June 28, 2006. The source water (ground water) contained around 20 µg/L of arsenic, existing predominatel...

  16. Oxidative DNA damage enhances the carcinogenic potential of in vitro chronic arsenic exposures.

    PubMed

    Bach, Jordi; Peremartí, Jana; Annangi, Balasubramanyam; Marcos, Ricard; Hernández, Alba

    2016-08-01

    Chronic exposure to arsenic is known to increase the incidence of cancer in humans. Our previous work demonstrated that environmentally relevant arsenic exposures generate an accelerated accumulation of pre-carcinogen 8-OH-dG DNA lesions under Ogg1-deficient backgrounds, but it remains unproved whether this observed arsenic-induced oxidative DNA damage (ODD) is certainly important in terms of cancer. Here, isogenic MEF Ogg1 (+/+) cells and MEF Ogg1 (-/-) cells-unable to properly eliminate 8-OH-dG from DNA-were exposed to 0.5, 1 and 2 µM of sodium arsenite for 40 weeks. The acquisition of an in vitro cancer-like phenotype was assessed throughout the exposure; matrix metalloproteinase (MMP) activities were measured by zymography, colony formation and promotion were evaluated by soft agar assay, and cellular invasiveness was measured by the transwell assay. Alterations in cellular morphology, growth and differentiation status were also included as complementary measures of transformation. MEF Ogg1 (-/-) cells showed a cancer-associated phenotype after 30 weeks of exposure, as indicated by morphological changes, increased proliferation, deregulated differentiation status, increased MMPs secretion, anchorage-independent cell growth and enhancement of tumor growth and invasiveness. Conversely, MEF Ogg1 (+/+) cells did not present changes in morphology or proliferation, exhibited a milder degree of gene deregulation and needed 10 weeks of additional exposure to the highest arsenite doses to show tumor enhancing effects. Thus, Ogg1 genetic background and arsenic-induced 8-OH-dG proved relevant for arsenic-mediated carcinogenic effects. To our knowledge, this is the first study directly linking ODD with arsenic carcinogenesis. PMID:26438402

  17. Enhancing arsenic mitigation in Bangladesh: findings from institutional, psychological, and technical investigations.

    PubMed

    Johnston, Richard; Hug, Stephan J; Inauen, Jennifer; Khan, Nasreen I; Mosler, Hans-Joachim; Yang, Hong

    2014-08-01

    success of arsenic mitigation in general - and installation of deep tubewells in particular - can be significantly enhanced. PMID:24377677

  18. A P53 target gene, PIG11, contributes to chemosensitivity of cells to arsenic trioxide.

    PubMed

    Liang, Xiao-Qiu; Cao, En-Hua; Zhang, Yan; Qin, Jing-Fen

    2004-07-01

    The tumor suppressor p53 regulates the expression of various genes that promote apoptosis. PIG11 (P53-induced gene 11), also referred to as TP53I11 (tumor protein p53 inducible protein 11), is a direct p53 target gene. Recent data demonstrated that PIG11 was up-regulated markedly in arsenic trioxide induced apoptosis by DDRT-PCR, suggesting a new class of p53 target genes that sensitize cells to the effects of chemotherapeutic agents. In this study, through the construction of a recombinant GFP-PIG11 expression vector and transfection of HEK293 cells with GFP or GFP-PIG11, the role of PIG11 in apoptosis was analyzed. Results demonstrated that the percentage (11.38%) of apoptotic cells with GFP-PIG11 transfection was higher than that (7.28%) of with only GFP transfection (P<0.05). At 24 h after 1 microM of arsenic trioxide treatment, apoptotic cells exhibited a significant increase in the expression of GFP-PIG11 (36.67%+/-2.78), in contrast, 10.50%+/-2.03 only GFP and 5.25%+/-0.96 vehicle control (P<0.01). In addition, we showed that intracellular content of reactive oxygen species (ROS) was 9.66+/-0.52 in GFP-PIG11 transfection, higher than 5.21+/-0.08 in GFP only and 5.99+/-0.45 in vehicle control (P<0.01). The above results suggest that overexpression of PIG11 could induce cell apoptosis in the low levels and enhanced the apoptotic effects of arsenic trioxide. The process could be involved in intracellular generation of ROS. PMID:15225615

  19. Enhancements of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) metabolism and carcinogenic risk via NNK/arsenic interaction

    SciTech Connect

    Lee, H.-L.; Chang, Louis W.; Wu, J.-P.; Ueng, Y.-F.; Tsai, M.-H.; Hsieh, Dennis Paul Hsientang; Lin Pinpin

    2008-02-15

    Epidemiological studies indicated an enhancement of cigarette smoke-induced carcinogenicity, including hepatocellular carcinoma, by arsenic. We believe that arsenic will enhance the expression of hepatic CYP2A enzyme and NNK metabolism (a cigarette smoke component), thus its metabolites, and carcinogenic DNA adducts. Male ICR mice were exposed to NNK (0.5 mg/mouse) and sodium arsenite (0, 10, or 20 mg/kg) daily via gavaging for 10 days and their urine was collected at day 10 for NNK metabolite analysis. Liver samples were also obtained for CYP2A enzyme and DNA adducts evaluations. Both the cyp2a4/5 mRNA levels and the CYP2A enzyme activity were significantly elevated in arsenic-treated mice liver. Furthermore, urinary NNK metabolites in NNK/arsenic co-treated mice also increased compared to those treated with NNK alone. Concomitantly, DNA adducts (N{sup 7}-methylguanine and O{sup 6}-methylguanine) were significantly elevated in the livers of mice co-treated with NNK and arsenic. Our findings provide clear evidence that arsenic increased NNK metabolism by up-regulation of CYP2A expression and activity leading to an increased NNK metabolism and DNA adducts (N{sup 7}-methylguanine and O{sup 6}-methylguanine). These findings suggest that in the presence of arsenic, NNK could induce greater DNA adducts formation in hepatic tissues resulting in higher carcinogenic potential.

  20. Acetaminophen increases the risk of arsenic-mediated development of hepatic damage in rats by enhancing redox-signaling mechanism.

    PubMed

    Majhi, Chhaya Rani; Khan, Saleem; Leo, Marie Dennis Marcus; Prawez, Shahid; Kumar, Amit; Sankar, Palanisamy; Telang, Avinash Gopal; Sarkar, Souvendra Nath

    2014-02-01

    We evaluated whether the commonly used analgesic-antipyretic drug acetaminophen can modify the arsenic-induced hepatic oxidative stress and also whether withdrawal of acetaminophen administration during the course of long-term arsenic exposure can increase susceptibility of liver to arsenic toxicity. Acetaminophen was co-administered orally to rats for 3 days following 28 days of arsenic pre-exposure (Phase-I) and thereafter, acetaminophen was withdrawn, but arsenic exposure was continued for another 28 days (Phase-II). Arsenic increased lipid peroxidation and reactive oxygen species (ROS) generation, depleted glutathione (GSH), and decreased superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and glutathione reductase (GR) activities. Acetaminophen caused exacerbation of arsenic-mediated lipid peroxidation and ROS generation and further enhancement of serum alanine aminotransferase and aspartate aminotransferase activities. In Phase-I, acetaminophen caused further GSH depletion and reduction in SOD, catalase, GPx and GR activities, but in Phase-II, only GPx and GR activities were more affected. Arsenic did not alter basal and inducible nitric oxide synthase (iNOS)-mediated NO production, but decreased constitutive NOS (cNOS)-mediated NO release. Arsenic reduced expression of endothelial NOS (eNOS) and iNOS genes. Acetaminophen up-regulated eNOS and iNOS expression and NO production in Phase-I, but reversed these effects in Phase-II. Results reveal that acetaminophen increased the risk of arsenic-mediated hepatic oxidative damage. Withdrawal of acetaminophen administration also increased susceptibility of liver to hepatotoxicity. Both ROS and NO appeared to mediate lipid peroxidation in Phase-I, whereas only ROS appeared responsible for peroxidative damage in Phase-II. PMID:22120977

  1. Arsenic Induces Functional Re-Expression of Estrogen Receptor α by Demethylation of DNA in Estrogen Receptor-Negative Human Breast Cancer

    PubMed Central

    Liu, Hongxia; Jiang, Fei; Wang, Yubang; Hu, Chunyan; Qi, Hong; Zhong, Caiyun; Wang, Xinru; Li, Zhong

    2012-01-01

    Estrogen receptor α (ERα) is a marker predictive for response of breast cancers to endocrine therapy. About 30% of breast cancers, however, are hormone- independent because of lack of ERα expression. New strategies are needed for re-expression of ERα and sensitization of ER-negative breast cancer cells to selective ER modulators. The present report shows that arsenic trioxide induces reactivated ERα, providing a target for therapy with ER antagonists. Exposure of ER-negative breast cancer cells to arsenic trioxide leads to re-expression of ERα mRNA and functional ERα protein in in vitro and in vivo. Luciferase reporter gene assays and 3-(4,5-dimethylthiazol-2-yl)- 5-(3-carboxymethoxyphenyl)- 2-(4-sulfophenyl)- 2H-tetrazolium (MTS) assays show that, upon exposure to arsenic trioxide, formerly unresponsive, ER-negative MDA-MB-231 breast cancer cells become responsive to ER antagonists, 4-hydroxytamoxifen and ICI 182,780. Furthermore, methylation- specific PCR and bisulfite-sequencing PCR assays show that arsenic trioxide induces partial demethylation of the ERα promoter. A methyl donor, S-adenosylmethionine (SAM), reduces the degree of arsenic trioxide-induced re-expression of ERα and demethylation. Moreover, Western blot and ChIP assays show that arsenic trioxide represses expression of DNMT1 and DNMT3a along with partial dissociation of DNMT1 from the ERα promoter. Thus, arsenic trioxide exhibits a previously undefined function which induces re-expression ERα in ER-negative breast cancer cells through demethylation of the ERα promoter. These findings could provide important information regarding the application of therapeutic agents targeting epigenetic changes in breast cancers and potential implication of arsenic trioxide as a new drug for the treatment of ER–negative human breast cancer. PMID:22558281

  2. IRON PROCESSES: SYSTEM MODIFICATION OF EXISTING PLANTS FOR ENHANCED ARSENIC REMOVAL

    EPA Science Inventory

    The recently promulgated Arsenic Rule will require that many new drinking water systems treat their water to remove arsenic. Many groundwaters that have arsenic in their source water also have iron in their water. As a result, arsenic treatment at these sites will most likely b...

  3. Surface-enhanced raman spectroscopy substrate for arsenic sensing in groundwater

    DOEpatents

    Yang, Peidong; Mulvihill, Martin; Tao, Andrea R.; Sinsermsuksakul, Prasert; Arnold, John

    2015-06-16

    A surface-enhanced Raman spectroscopy (SERS) substrate formed from a plurality of monolayers of polyhedral silver nanocrystals, wherein at least one of the monolayers has polyvinypyrrolidone (PVP) on its surface, and thereby configured for sensing arsenic is described. Highly active SERS substrates are formed by assembling high density monolayers of differently shaped silver nanocrystals onto a solid support. SERS detection is performed directly on this substrate by placing a droplet of the analyte solution onto the nanocrystal monolayer. Adsorbed polymer, polyvinypyrrolidone (PVP), on the surface of the nanoparticles facilitates the binding of both arsenate and arsenite near the silver surface, allowing for highly accurate and sensitive detection capabilities.

  4. Arsenic Mobilization Is Enhanced by Thermal Transformation of Schwertmannite.

    PubMed

    Johnston, Scott G; Burton, Edward D; Moon, Ellen M

    2016-08-01

    Fires in iron-rich seasonal wetlands can thermally transform Fe(III) minerals and alter their crystallinity. However, the fate of As associated with thermally transformed Fe(III) minerals is unclear, as are the consequences for As mobilization during subsequent reflooding and reductive cycles. Here, we subject As(V)-coprecipitated schwertmannite to thermal transformation (200, 400, 600 and 800 °C) followed by biotic reductive incubation (150 d) and examine aqueous- and solid-phase speciation of As, Fe and S. Heating to >400 °C caused transformation of schwertmannite to a nanocrystalline hematite with greater surface area and smaller particle size. Higher temperatures also caused the initially structurally incorporated As to become progressively more exchangeable, increasing surface-complexed As (AsEx) by up to 60-fold, thereby triggering enhanced As mobilization during incubation (∼70-fold in the 800 °C treatment). Although more As was mobilized in biotic treatments than controls (∼3-20×), in both cases it was directly proportional to initial AsEx and mainly due to abiotic desorption. Higher transformation temperatures also drove divergent pathways of Fe and S biomineralization and led to more As(V) and SO4 reduction relative to Fe(III) reduction. This study reveals thermal transformation of schwertmannite can greatly increase As mobility and has major consequences for As/Fe/S speciation under reducing conditions. Further research is warranted to unravel the wider implications for water quality in natural wetlands. PMID:27403840

  5. Phosphorus solubilization and plant growth enhancement by arsenic-resistant bacteria.

    PubMed

    Ghosh, Piyasa; Rathinasabapathi, Bala; Ma, Lena Q

    2015-09-01

    Phosphorus is an essential nutrient, which is limited in most soils. The P solubilization and growth enhancement ability of seven arsenic-resistant bacteria (ARB), which were isolated from arsenic hyperaccumulator Pteris vittata, was investigated. Siderophore-producing ARB (PG4, 5, 6, 9, 10, 12 and 16) were effective in solubilizing P from inorganic minerals FePO4 and phosphate rock, and organic phytate. To reduce bacterial P uptake we used filter-sterilized Hoagland medium containing siderophores or phytase produced by PG12 or PG6 to grow tomato plants supplied with FePO4 or phytate. To confirm that siderophores were responsible for P release, we compared the mutants of siderophore-producing bacterium Pseudomonas fluorescens Pf5 (PchA) impaired in siderophore production with the wild type and test strains. After 7d of growth, mutant PchA solubilized 10-times less P than strain PG12, which increased tomato root biomass by 1.7 times. For phytate solubilization by PG6, tomato shoot biomass increased by 44% than control bacterium Pseudomonas chlororaphis. P solubilization by ARB from P. vittata may be useful in enhancing plant growth and nutrition in other crop plants. PMID:25880602

  6. Enhanced solubilization of arsenic and 2,3,4,6 tetrachlorophenol from soils by a cyclodextrin derivative.

    PubMed

    Chatain, V; Hanna, K; de Brauer, C; Bayard, R; Germain, P

    2004-10-01

    The application of extracting aqueous solutions with cyclodextrins in several soil remediation technologies has been increasingly studied but little is known about their removal capacities toward the inorganic species. Herein, the effectiveness of cyclodextrins (CDs) in extracting arsenic, copper, and iron from a mining soil is presented. In a preliminary test of four types of CD aqueous solutions, only the addition of carboxylmethyl-beta-cyclodextrin CMCD (a cyclodextrin derivative) led to a significant enhancement in arsenic removal. An increase in the concentration of copper and iron in the leachates was also observed with CMCD. Kinetic study of arsenic release was carried out at two temperatures (20 and 35 degrees C). The arsenic concentration in the leachates increases with increasing cyclodextrin concentration. At an 80 mM CMCD concentration, arsenic, copper, and iron released in filtrates were about 20-, 1,000-, and 4,000-fold greater, respectively, than that obtained using deionized water. In the soil system, the CMCD capacity removal was found to be higher for cations than for arsenic. Because the tetrachlorophenol can co-occur with arsenic and copper in several contaminated sites, its solubilization by CMCD was also investigated. Extraction experiments were performed to extract 2,3,4,6 tetrachlorophenol (TeCP) in spiked soil with CMCD. The results of batch experiments have shown that CMCD could significantly increase the TeCP extraction from soil. CD sorption on soils as quantified by a fluorescence technique was low, indicating no significant loss of CD during the leaching experiments. The use of CMCD as a flushing agent to enhance the removal of both inorganic and organic pollutants from mixed-contaminated soils appears as a promising remediation method. PMID:15312736

  7. Biomineralization of arsenate to arsenic sulfides is greatly enhanced at mildly acidic conditions.

    PubMed

    Rodriguez-Freire, Lucia; Sierra-Alvarez, Reyes; Root, Robert; Chorover, Jon; Field, James A

    2014-12-01

    Arsenic (As) is an important water contaminant due to its high toxicity and widespread occurrence. Arsenic-sulfide minerals (ASM) are formed during microbial reduction of arsenate (As(V)) and sulfate (SO4(2-)). The objective of this research is to study the effect of the pH on the removal of As due to the formation of ASM in an iron-poor system. A series of batch experiments was used to study the reduction of SO4(2-) and As(V) by an anaerobic biofilm mixed culture in a range of pH conditions (6.1-7.2), using ethanol as the electron donor. Total soluble concentrations and speciation of S and As were monitored. Solid phase speciation of arsenic was characterized by x-ray adsorption spectroscopy (XAS). A marked decrease of the total aqueous concentrations of As and S was observed in the inoculated treatments amended with ethanol, but not in the non-inoculated controls, indicating that the As-removal was biologically mediated. The pH dramatically affected the extent and rate of As removal, as well as the stoichiometric composition of the precipitate. The amount of As removed was 2-fold higher and the rate of the As removal was up to 17-fold greater at pH 6.1 than at pH 7.2. Stoichiometric analysis and XAS results confirmed the precipitate was composed of a mixture of orpiment and realgar, and the proportion of orpiment in the sample increased with increasing pH. The results taken as a whole suggest that ASM formation is greatly enhanced at mildly acidic pH conditions. PMID:25222328

  8. Biomineralization of Arsenate to Arsenic Sulfides is Greatly Enhanced at Mildly Acidic Conditions

    PubMed Central

    Rodriguez-Freire, Lucia; Sierra-Alvarez, Reyes; Root, Robert; Chorover, Jon; Field, James A.

    2014-01-01

    Arsenic (As) is an important water contaminant due to its high toxicity and widespread occurrence. Arsenic-sulfide minerals (ASM) are formed during microbial reduction of arsenate (AsV) and sulfate (SO42−). The objective of this research is to study the effect of the pH on the removal of As due to the formation of ASM in an iron-poor system. A series of batch experiments was used to study the reduction of SO42− and AsV by an anaerobic biofilm mixed culture in a range of pH conditions (6.1–7.2), using ethanol as the electron donor. Total soluble concentrations and speciation of S and As were monitored. Solid phase speciation of arsenic was characterized by x-ray adsorption spectroscopy (XAS). A marked decrease of the total aqueous concentrations of As and S was observed in the inoculated treatments amended with ethanol, but not in the non-inoculated controls, indicating that the As-removal was biologically mediated. The pH dramatically affected the extent and rate of As removal, as well as the stoichiometric composition of the precipitate. The amount of As removed was 2-fold higher and the rate of the As removal was up to 17-fold greater at pH 6.1 than at pH 7.2. Stoichiometric analysis and XAS results confirmed the precipitate was composed of a mixture of orpiment and realgar, and the proportion of orpiment in the sample increased with increasing pH. The results taken as a whole suggest that ASM formation is greatly enhanced at mildly acidic pH conditions. PMID:25222328

  9. Hyperoside enhances the suppressive effects of arsenic trioxide on acute myeloid leukemia cells

    PubMed Central

    Zhang, Feng; Zhu, Fang-Bing; Li, Jia-Jia; Zhang, Ping-Ping; Zhu, Jun-Feng

    2015-01-01

    Hyperoside (Hyp) is the chief component of some Chinese herbs which has anticancer effect and the present study is to identify whether it could enhance the anti leukemic properties of arsenic trioxide (As2O3) in acute myeloid leukemia (AML). We provide evidence on the concomitant treatment of HL-60 human AML cells with hyperoside potentiates As2O3-dependent induction of apoptosis. The activation of caspase-9, Bcl-2-associated agonist of cell death (BAD), p-BAD, p27 was assessed by Western blot. Results showed that hyperoside inhibited BAD from phosphorylating, reactivated caspase-9, and increased p27 levels. Importantly, hyperoside demonstrated its induction of autophagy effect by upregulation of LC-II in HL-60 AML cell line. Taken together, hyperoside may serve as a great candidate of concomitant treatment for leukemia; these effects were probably related to induction of autophagy and enhancing apoptosis-inducing action of As2O3. PMID:26629016

  10. FOLATE DEFICIENCY ENHANCES ARSENIC EFFECTS ON EXPRESSION OF GENES INVOLVED IN EPIDERMAL DIFFERENTIATION

    EPA Science Inventory

    Chronic arsenic exposure in humans is associated with cancers of the skin, lung, and bladder. There is evidence that folate deficiency may increase susceptibility to arsenic¿s effects, including arsenic-induced skin lesions. K6/ODC mice develop skin tumors when exposed to 10 ppm ...

  11. Mechanism of Selenium-Induced Inhibition of Arsenic-Enhanced UVR Carcinogenesis in Mice

    PubMed Central

    Burns, Fredric J.; Rossman, Toby; Vega, Katherine; Uddin, Ahmed; Vogt, Stefan; Lai, Barry; Reeder, Richard J.

    2008-01-01

    Background Hairless mice that ingested arsenite in drinking water exhibited more than a 5-fold enhancement of ultraviolet radiation (UVR) carcinogenesis, whereas arsenite alone was carcinogenically inactive. Dietary organoselenium blocked the cancer enhancement effect of arsenic but not cancer induction by UVR. Objective In this study we sought to explain selenium blockage of As enhancement by establishing the extent that As and Se tissue distributions are coincident or divergent. Methods We used the X-ray fluorescence microprobe at the Advanced Photon Source (Argonne National Laboratory) to probe sections of skin and liver from hairless mice exposed to a) UVR, b) UVR + As, c) UVR + organoselenium, or d) UVR + As + organoselenium. Results We found elevated levels of As in the skin epithelium (hair follicles and epidermis) and diffusely in the liver of mice exposed to UVR + As. Arsenic was entirely absent in skin in mice exposed to UVR + As + organoselenium, but a diffuse low level was seen in the liver. As and Se locations were consistently divergent in skin; As was more diffusely distributed, whereas Se was strongly associated with membranes. X-ray absorption near-edge spectra are consistent with the presence of the seleno-bis(S-glutathionyl) arsinium ion in the liver. Conclusions Supplemental Se was uncommonly effective at preventing even a trace of As in skin at 14 or 196 days of continuous exposure to As in drinking water. Traces of the seleno-bis(S-glutathionyl) arsinium ion in the liver suggested that formation of this compound was more likely to be responsible for the As-blocking effect of Se than was a mechanism based on antioxidation. PMID:18560523

  12. Subchronic Arsenic Exposure Induces Anxiety-Like Behaviors in Normal Mice and Enhances Depression-Like Behaviors in the Chemically Induced Mouse Model of Depression.

    PubMed

    Chang, Chia-Yu; Guo, How-Ran; Tsai, Wan-Chen; Yang, Kai-Lin; Lin, Li-Chuan; Cheng, Tain-Junn; Chuu, Jiunn-Jye

    2015-01-01

    Accumulating evidence implicates that subchronic arsenic exposure causes cerebral neurodegeneration leading to behavioral disturbances relevant to psychiatric disorders. However, there is still little information regarding the influence of subchronic exposure to arsenic-contaminated drinking water on mood disorders and its underlying mechanisms in the cerebral prefrontal cortex. The aim of this study is to assess the effects of subchronic arsenic exposure (10 mg/LAs2O3 in drinking water) on the anxiety- and depression-like behaviors in normal mice and in the chemically induced mouse model of depression by reserpine pretreatment. Our findings demonstrated that 4 weeks of arsenic exposure enhance anxiety-like behaviors on elevated plus maze (EPM) and open field test (OFT) in normal mice, and 8 weeks of arsenic exposure augment depression-like behaviors on tail suspension test (TST) and forced swimming test (FST) in the reserpine pretreated mice. In summary, in this present study, we demonstrated that subchronic arsenic exposure induces only the anxiety-like behaviors in normal mice and enhances the depression-like behaviors in the reserpine induced mouse model of depression, in which the cerebral prefrontal cortex BDNF-TrkB signaling pathway is involved. We also found that eight weeks of subchronic arsenic exposure are needed to enhance the depression-like behaviors in the mouse model of depression. These findings imply that arsenic could be an enhancer of depressive symptoms for those patients who already had the attribute of depression. PMID:26114099

  13. Subchronic Arsenic Exposure Induces Anxiety-Like Behaviors in Normal Mice and Enhances Depression-Like Behaviors in the Chemically Induced Mouse Model of Depression

    PubMed Central

    Chang, Chia-Yu; Guo, How-Ran; Tsai, Wan-Chen; Yang, Kai-Lin; Lin, Li-Chuan

    2015-01-01

    Accumulating evidence implicates that subchronic arsenic exposure causes cerebral neurodegeneration leading to behavioral disturbances relevant to psychiatric disorders. However, there is still little information regarding the influence of subchronic exposure to arsenic-contaminated drinking water on mood disorders and its underlying mechanisms in the cerebral prefrontal cortex. The aim of this study is to assess the effects of subchronic arsenic exposure (10 mg/LAs2O3 in drinking water) on the anxiety- and depression-like behaviors in normal mice and in the chemically induced mouse model of depression by reserpine pretreatment. Our findings demonstrated that 4 weeks of arsenic exposure enhance anxiety-like behaviors on elevated plus maze (EPM) and open field test (OFT) in normal mice, and 8 weeks of arsenic exposure augment depression-like behaviors on tail suspension test (TST) and forced swimming test (FST) in the reserpine pretreated mice. In summary, in this present study, we demonstrated that subchronic arsenic exposure induces only the anxiety-like behaviors in normal mice and enhances the depression-like behaviors in the reserpine induced mouse model of depression, in which the cerebral prefrontal cortex BDNF-TrkB signaling pathway is involved. We also found that eight weeks of subchronic arsenic exposure are needed to enhance the depression-like behaviors in the mouse model of depression. These findings imply that arsenic could be an enhancer of depressive symptoms for those patients who already had the attribute of depression. PMID:26114099

  14. Signal enhancement of lead and arsenic in soil using laser ablation combined with fast electric discharge

    NASA Astrophysics Data System (ADS)

    Kexue, L. I.; Zhou, Weidong; Shen, Qinmei; Shao, Jie; Qian, Huiguo

    2010-05-01

    In comparison to the traditional single pulse laser induced breakdown spectroscopy (SP-LIBS), a significant enhancement of atomic emission of lead and arsenic from laser plasma of soil has been demonstrated by the use of a laser ablation and fast pulse discharge plasma spectroscopy technique (LA-FPDPS). In this technique, a specifically designed high voltage and rapid discharge circuit was used to reheat the laser plasma and to enhance the plasma emission. A rapid and time damped alternating discharge current was observed with a short oscillating period ˜ 0.6 μs and sustained for about 6 μs. The peak intensities of Pb (283.31 nm) and As (286.04 nm) lines from soil plasma emission were greatly enhanced when compare to the traditional single pulse (SP) LIBS system. In addition, the precision of measurements in terms of the relative standard deviation (RSD) and the signal to noise ( S/ N) ratios were also improved. Scanning electron microscopy (SEM) images of the laser ablation regions indicated that the plasma reheating by the discharge spark was presumably the main mechanism for observed signal enhancement in the LA-FPDPS technique.

  15. Enhanced urinary bladder and liver carcinogenesis in male CD1 mice exposed to transplacental inorganic arsenic and postnatal diethylstilbestrol or tamoxifen

    SciTech Connect

    Waalkes, Michael P. . E-mail: waalkes@niehs.nih.gov; Liu Jie; Ward, Jerrold M.; Diwan, Bhalchandra A.

    2006-09-15

    Pregnant CD1 mice received 85 ppm arsenite in the drinking water from gestation day 8 to 18, groups (n = 35) of male offspring were subsequently injected on postpartum days 1 through 5 with diethylstilbestrol (DES; 2 {mu}g/pup/day) or tamoxifen (TAM; 10 {mu}g/pup/day), and tumor formation was assessed over 90 weeks. Arsenic alone increased hepatocellular carcinoma (14%), adenoma (23%) and total tumors (31%) compared to control (0, 2 and 2%, respectively). Arsenic alone also increased lung adenocarcinoma, adrenal cortical adenoma and renal cystic tubular hyperplasia compared to control. Compared to arsenic alone, arsenic plus DES increased liver tumor incidence in mice at risk 2.2-fold and increased liver tumor multiplicity (tumors/liver) 1.8-fold. The treatments alone did not impact urinary bladder carcinogenesis, but arsenic plus TAM significantly increased formation of urinary bladder transitional cell tumors (papilloma and carcinoma; 13%) compared to control (0%). Urinary bladder proliferative lesions (combined tumors and hyperplasia) were also increased by arsenic plus TAM (40%) or arsenic plus DES (43%) compared to control (0%) or the treatments alone. Urinary bladder proliferative lesions occurred in the absence of any evidence of uroepithelial cytotoxic lesions. Urinary bladder lesions and hepatocellular carcinoma induced by arsenic plus TAM and/or DES overexpressed estrogen receptor-{alpha}, indicating that aberrant estrogen signaling may have been a factor in the enhanced carcinogenic response. Thus, in male CD1 mice, gestational arsenic exposure alone induced liver adenoma and carcinoma, lung adenocarcinoma, adrenal adenoma and renal cystic hyperplasia. Furthermore, DES enhanced transplacental arsenic-induced hepatocarcinogenesis. In utero arsenic also initiated urinary bladder tumor formation when followed by postnatal TAM and uroepithelial proliferative lesions when followed by TAM or DES.

  16. Atorvastatin ameliorates arsenic-induced hypertension and enhancement of vascular redox signaling in rats

    SciTech Connect

    Sarath, Thengumpallil Sasindran; Waghe, Prashantkumar; Gupta, Priyanka; Choudhury, Soumen; Kannan, Kandasamy; Pillai, Ayyappan Harikrishna; Harikumar, Sankaran Kutty; Mishra, Santosh Kumar; Sarkar, Souvendra Nath

    2014-11-01

    Chronic arsenic exposure has been linked to elevated blood pressure and cardiovascular diseases, while statins reduce the incidence of cardiovascular disease predominantly by their low density lipoprotein-lowering effect. Besides, statins have other beneficial effects, including antioxidant and anti-inflammatory activities. We evaluated whether atorvastatin, a widely used statin, can ameliorate arsenic-induced increase in blood pressure and alteration in lipid profile and also whether the amelioration could relate to altered NO and ROS signaling. Rats were exposed to sodium arsenite (100 ppm) through drinking water for 90 consecutive days. Atorvastatin (10 mg/kg bw, orally) was administered once daily during the last 30 days of arsenic exposure. On the 91st day, blood was collected for lipid profile. Western blot of iNOS and eNOS protein, NO and 3-nitrotyrosine production, Nox-4 and p22Phox mRNA expression, Nox activity, ROS generation, lipid peroxidation and antioxidants were evaluated in thoracic aorta. Arsenic increased systolic, diastolic and mean arterial blood pressure, while it decreased HDL-C and increased LDL-C, total cholesterol and triglycerides in serum. Arsenic down-regulated eNOS and up-regulated iNOS protein expression and increased basal NO and 3-nitrotyrosine level. Arsenic increased aortic Nox-4 and p22Phox mRNA expression, Nox activity, ROS generation and lipid peroxidation. Further, arsenic decreased the activities of superoxide dismutase, catalase, and glutathione peroxidase and depleted aortic GSH content. Atorvastatin regularized blood pressure, improved lipid profile and attenuated arsenic-mediated redox alterations. The results demonstrate that atorvastatin has the potential to ameliorate arsenic-induced hypertension by improving lipid profile, aortic NO signaling and restoring vascular redox homeostasis. - Highlights: • Arsenic increased systolic, diastolic and mean arterial blood pressure and caused dyslipidemia. • Arsenic increased

  17. Arsenic transformation predisposes human skin keratinocytes to UV-induced DNA damage yet enhances their survival apparently by diminishing oxidant response

    SciTech Connect

    Sun Yang; Kojima, Chikara; Chignell, Colin; Mason, Ronald; Waalkes, Michael P.

    2011-09-15

    Inorganic arsenic and UV, both human skin carcinogens, may act together as skin co-carcinogens. We find human skin keratinocytes (HaCaT cells) are malignantly transformed by low-level arsenite (100 nM, 30 weeks; termed As-TM cells) and with transformation concurrently undergo full adaptation to arsenic toxicity involving reduced apoptosis and oxidative stress response to high arsenite concentrations. Oxidative DNA damage (ODD) is a possible mechanism in arsenic carcinogenesis and a hallmark of UV-induced skin cancer. In the current work, inorganic arsenite exposure (100 nM) did not induce ODD during the 30 weeks required for malignant transformation. Although acute UV-treatment (UVA, 25 J/cm{sup 2}) increased ODD in passage-matched control cells, once transformed by arsenic to As-TM cells, acute UV actually further increased ODD (> 50%). Despite enhanced ODD, As-TM cells were resistant to UV-induced apoptosis. The response of apoptotic factors and oxidative stress genes was strongly mitigated in As-TM cells after UV exposure including increased Bcl2/Bax ratio and reduced Caspase-3, Nrf2, and Keap1 expression. Several Nrf2-related genes (HO-1, GCLs, SOD) showed diminished responses in As-TM cells after UV exposure consistent with reduced oxidant stress response. UV-exposed As-TM cells showed increased expression of cyclin D1 (proliferation gene) and decreased p16 (tumor suppressor). UV exposure enhanced the malignant phenotype of As-TM cells. Thus, the co-carcinogenicity between UV and arsenic in skin cancer might involve adaptation to chronic arsenic exposure generally mitigating the oxidative stress response, allowing apoptotic by-pass after UV and enhanced cell survival even in the face of increased UV-induced oxidative stress and increased ODD. - Highlights: > Arsenic transformation adapted to UV-induced apoptosis. > Arsenic transformation diminished oxidant response. > Arsenic transformation enhanced UV-induced DNA damage.

  18. Arsenic Remediation Enhancement Through Chemical Additions to Pump and Treat Operations

    NASA Astrophysics Data System (ADS)

    Wovkulich, K.; Mailloux, B. J.; Stute, M.; Simpson, H. J.; Keimowitz, A. R.; Powell, A.; Lacko, A.; Chillrud, S. N.

    2008-12-01

    Arsenic is a contaminant found at more than 500 US Superfund sites. Since pump and treat technologies are widely used for remediation of contaminated groundwater, increasing the efficiency of contaminant removal at such sites should allow limited financial resources to clean up more sites. The Vineland Chemical Company Superfund site is extensively contaminated with arsenic after waste arsenic salts were stored and disposed of improperly for much of the company's 44 year manufacturing lifetime. Despite approximately eight years of pump and treat remediation, arsenic concentrations in the recovery wells can still be greater than 1000 ppb. The arsenic concentrations in the groundwater remain high because of slow desorption of arsenic from contaminated aquifer solids. Extrapolation of laboratory column experiments suggest that continuing the current groundwater remediation practice based on flushing ambient groundwater through the system may require on the order of hundreds of years to clean the site. However, chemical additions of phosphate or oxalic acid into the aquifer could decrease the remediation time scale substantially. Laboratory results from a soil column experiment using input of 10 mM oxalic acid suggest that site clean up of groundwater could be decreased to as little as four years. Pilot scale forced gradient field experiments will help establish whether chemical additions can be effective for increasing arsenic mobilization from aquifer solids and thus substantially decrease pump and treat clean up time.

  19. Enhanced protective activity of nano formulated andrographolide against arsenic induced liver damage.

    PubMed

    Das, Sujata; Pradhan, Goutam Kumar; Das, Subhadip; Nath, Debjani; Das Saha, Krishna

    2015-12-01

    Chronic exposure to arsenic over a period of time induces toxicity, primarily in liver but gradually in all systems of the body. Andrographolide (AG), a major diterpene lactone of Andrographis paniculata, shows a wide array of physiological functions including hepatoprotection. Therapeutic applications of AG are however seriously constrained because of its insolubility, poor bioavailability, and short plasma half-life. Nanoparticulation of AG is a possible solution to these problems. In the present study we investigated the effectiveness of polylactide co-glycolide (PLGA) nanocapsulated andrographolide (NA) against arsenic induced liver damage in mice. NA of average diameter 65.8 nm and encapsulation efficiency of 64% were prepared. Sodium arsenite at a dose of 40 mg/L supplied via drinking water in mice significantly raised the serum level of liver function markers such as AST, ALT, and ALP, and caused arsenic deposition in liver and ROS generation, though it did not show any lethality up to 30 days of exposure. However, even liver toxicity was not observed when mice were given AG and NA orally at doses up to 100 mg/kg bwt and 20 mg/kg bwt respectively on alternate days for one month. Treatment of non-toxic doses of AG or NA on alternate days along with arsenic significantly decreased the arsenic induced elevation of the serum level of ALT, AST and ALP, and arsenic deposition in liver. AG and NA increased the level of hepatic antioxidant enzymes such as superoxide dismutase (SOD), and catalase (CAT), and the level of reduced glutathione (GSH). Also, the ROS level was lowered in mice exposed to arsenic but treated with AG or NA. Protective efficiency of NA is about five times more than that of AG. Administration of NA to arsenic-treated mice caused signs of improvement in liver tissue architecture. In conclusion, the results of this study suggest that NA could be beneficial against arsenic-induced liver toxicity. PMID:26485141

  20. Nicotinamide enhances repair of arsenic and ultraviolet radiation-induced DNA damage in HaCaT keratinocytes and ex vivo human skin.

    PubMed

    Thompson, Benjamin C; Halliday, Gary M; Damian, Diona L

    2015-01-01

    Arsenic-induced skin cancer is a significant global health burden. In areas with arsenic contamination of water sources, such as China, Pakistan, Myanmar, Cambodia and especially Bangladesh and West Bengal, large populations are at risk of arsenic-induced skin cancer. Arsenic acts as a co-carcinogen with ultraviolet (UV) radiation and affects DNA damage and repair. Nicotinamide (vitamin B3) reduces premalignant keratoses in sun-damaged skin, likely by prevention of UV-induced cellular energy depletion and enhancement of DNA repair. We investigated whether nicotinamide modifies DNA repair following exposure to UV radiation and sodium arsenite. HaCaT keratinocytes and ex vivo human skin were exposed to 2μM sodium arsenite and low dose (2J/cm2) solar-simulated UV, with and without nicotinamide supplementation. DNA photolesions in the form of 8-oxo-7,8-dihydro-2'-deoxyguanosine and cyclobutane pyrimidine dimers were detected by immunofluorescence. Arsenic exposure significantly increased levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine in irradiated cells. Nicotinamide reduced both types of photolesions in HaCaT keratinocytes and in ex vivo human skin, likely by enhancing DNA repair. These results demonstrate a reduction of two different photolesions over time in two different models in UV and arsenic exposed cells. Nicotinamide is a nontoxic, inexpensive agent with potential for chemoprevention of arsenic induced skin cancer. PMID:25658450

  1. [Study on an enhancing agent for removing arsenic from drinking water].

    PubMed

    Ling, B; Li, S; Zhu, Y; Zhang, B

    2001-05-01

    Drinking water contaminated by arsenic for an extended period of time could be detrimental to the health of people. Some preliminary symptoms could be alleviated by drinking water non-contaminated. It is important to develop an arsenic removal agent with a specific property of most efficient, cost-effective and easy for operation. The results showed that the capacity of the agent developed in this study was 10 times higher for arsenic removal than other agent available. The lowest arsenic content of the treated water was 0.05 mg/L. The special function of this agent was arsenic removing without changing other components and the concentrations of other elements in the treated water. The operation and management was simple without adjusting pH of the influent and effluent water. The agent was 5 times cheaper in cost than alumina or activated carbon, because it was a reusable oxidation-catalyst. Therefore, the agent could be widely applied in drinking water plants or used as a purifier at home in the high arsenic areas. PMID:12525087

  2. Preferential action of arsenic trioxide in solid-tumor microenvironment enhances radiation therapy

    SciTech Connect

    Griffin, Robert J. . E-mail: griff007@umn.edu; Williams, Brent W.; Park, Heon Joo; Song, Chang W.

    2005-04-01

    Purpose: To investigate the effect of arsenic trioxide, Trisenox (TNX), on primary cultures of endothelial cells and tumor tissue under varying pH and pO{sub 2} environments and the effects of combined TNX and radiation therapy on experimental tumors. Methods and Materials: Human dermal microvascular endothelial cells were cultured in vitro and exposed to TNX under various combinations of aerobic, hypoxic, neutral, or acidic conditions, and levels of activated JNK MAP kinase were assessed by Western blotting. FSaII fibrosarcoma cells grown in the hind limb of female C3H mice were used to study the effect of TNX on tumor blood perfusion and oxygenation. The tumor-growth delay after a single or fractionated irradiation with or without TNX treatment was assessed. Results: A single intraperitoneal injection of 8 mg/kg TNX reduced the blood perfusion in FSaII tumors by 53% at 2 hours after injection. To increase the oxygenation of the tumor vasculature during TNX treatment, some animals were allowed to breathe carbogen (95% O{sub 2}/5% CO{sub 2}). Carbogen breathing alone for 2 hours reduced tumor perfusion by 33%. When carbogen breathing was begun immediately after TNX injection, no further reduction occurred in tumor blood perfusion at 2 hours after injection. In vitro, TNX exposure increased activity JNK MAP kinase preferentially in endothelial cells cultured in an acidic or hypoxic environment. In vivo, the median oxygenation in FSaII tumors measured at 3 or 5 days after TNX injection was found to be significantly elevated compared with control tumors. Subsequently, radiation-induced tumor-growth delay was synergistically increased when radiation and TNX injection were fractionated at 3-day or 5-day intervals. Conclusions: Trisenox has novel vascular-damaging properties, preferentially against endothelium in regions of low pH or pO{sub 2}, which leads to tumor cell death and enhancement of the response of tumors to radiotherapy.

  3. Overexpression of phytochelatin synthase in Arabidopsis leads to enhanced arsenic tolerance and cadmium hypersensitivity.

    PubMed

    Li, Yujing; Dhankher, Om Parkash; Carreira, Laura; Lee, David; Chen, Alice; Schroeder, Julian I; Balish, Rebecca S; Meagher, Richard B

    2004-12-01

    Phytochelatin synthase (PCS) catalyzes the final step in the biosynthesis of phytochelatins, which are a family of cysteine-rich thiol-reactive peptides believed to play important roles in processing many thiol-reactive toxicants. A modified Arabidopsis thaliana PCS sequence (AtPCS1) was active in Escherichia coli. When AtPCS1 was overexpressed in Arabidopsis from a strong constitutive Arabidopsis actin regulatory sequence (A2), the A2::AtPCS1 plants were highly resistant to arsenic, accumulating 20-100 times more biomass on 250 and 300 microM arsenate than wild type (WT); however, they were hypersensitive to Cd(II). After exposure to cadmium and arsenic, the overall accumulation of thiol-peptides increased to 10-fold higher levels in the A2::AtPCS1 plants compared with WT, as determined by fluorescent HPLC. Whereas cadmium induced greater increases in traditional PCs (PC2, PC3, PC4), arsenic exposure resulted in the expression of many unknown thiol products. Unexpectedly, after arsenate or cadmium exposure, levels of the dipeptide substrate for PC synthesis, gamma-glutamyl cysteine (gamma-EC), were also dramatically increased. Despite these high thiol-peptide concentrations, there were no significant increases in concentrations of arsenic and cadmium in above-ground tissues in the AtPCS1 plants relative to WT plants. The potential for AtPCS1 overexpression to be useful in strategies for phytoremediating arsenic and to compound the negative effects of cadmium are discussed. PMID:15653797

  4. Sprinkler irrigation of rice fields reduces grain arsenic but enhances cadmium.

    PubMed

    Moreno-Jiménez, Eduardo; Meharg, Andrew A; Smolders, Erik; Manzano, Rebeca; Becerra, Daniel; Sánchez-Llerena, Javier; Albarrán, Ángel; López-Piñero, Antonio

    2014-07-01

    Previous studies have demonstrated that rice cultivated under flooded conditions has higher concentrations of arsenic (As) but lower cadmium (Cd) compared to rice grown in unsaturated soils. To validate such effects over long terms under Mediterranean conditions a field experiment, conducted over 7 successive years was established in SW Spain. The impact of water management on rice production and grain arsenic (As) and cadmium (Cd) was measured, and As speciation was determined to inform toxicity evaluation. Sprinkler irrigation was compared to traditional flooding. Both irrigation techniques resulted in similar grain yields (~3000 kg grain ha(-1)). Successive sprinkler irrigation over 7 years decreased grain total As to one-sixth its initial concentration in the flooded system (0.55 to 0.09 mg As kg(-1)), while one cycle of sprinkler irrigation also reduced grain total As by one-third (0.20 mg kg(-1)). Grain inorganic As concentration increased up to 2 folds under flooded conditions compared to sprinkler irrigated fields while organic As was also lower in sprinkler system treatments, but to a lesser extent. This suggests that methylation is favored under water logging. However, sprinkler irrigation increased Cd transfer to grain by a factor of 10, reaching 0.05 mg Cd kg(-1) in 7 years. Sprinkler systems in paddy fields seem particularly suited for Mediterranean climates and are able to mitigate against excessive As accumulation, but our evidence shows that an increased Cd load in rice grain may result. PMID:24742557

  5. Enhancement of Arsenic Trioxide-Mediated Changes in Human Induced Pluripotent Stem Cells (IPS)

    PubMed Central

    Graham, Barbara; Stevens, Jacqueline; Wells, Phatia; Sims, Jennifer; Rogers, Christian; Leggett, Sophia S.; Ekunwe, Stephen; Ndebele, Kenneth

    2014-01-01

    Induced pluripotent stem cells (IPS) are an artificially derived type of pluripotent stem cell, showing many of the same characteristics as natural pluripotent stem cells. IPS are a hopeful therapeutic model; however there is a critical need to determine their response to environmental toxins. Effects of arsenic on cells have been studied extensively; however, its effect on IPS is yet to be elucidated. Arsenic trioxide (ATO) has been shown to inhibit cell proliferation, induce apoptosis and genotoxicity in many cells. Based on ATOs action in other cells, we hypothesize that it will induce alterations in morphology, inhibit cell viability and induce a genotoxic effect on IPS. Cells were treated for 24 hours with ATO (0–9 µg/mL). Cell morphology, viability and DNA damage were documented. Results indicated sufficient changes in morphology of cell colonies mainly in cell ability to maintain grouping and ability to remain adherent. Cell viability decreased in a dose dependent manner. There were significant increases in tail length and moment as well as destruction of intact DNA as concentration increased. Exposure to ATO resulted in a reproducible dose dependent sequence of events marked by changes in morphology, decrease of cell viability, and induction of genotoxicity in IPS. PMID:25054231

  6. DNA-strand breaks induced by dimethylarsinic acid, a metabolite of inorganic arsenics, are strongly enhanced by superoxide anion radicals.

    PubMed

    Rin, K; Kawaguchi, K; Yamanaka, K; Tezuka, M; Oku, N; Okada, S

    1995-01-01

    We previously reported that dimethylarsinic acid (DMAA), a major metabolite of inorganic arsenics, induced DNA single-strand breaks (ssb) both in vivo and in cultured alveolar type II (L-132) cells in vitro, possibly via the production of dimethylarsenic peroxyl radicals. Here, the interaction of superoxide anion radicals (O2-) in the induction of ssb in L-132 cells was investigated using paraquat, an O2(-)-producing agent. A significant enhancement of ssb formation was observed in the DMAA-exposed cells when coexposed to paraquat. This enhancement occurred even when post-exposed to DMAA after washing, suggesting that the DMAA exposure caused some modification of DNA such as DNA-adducts, which was recognized by active oxygens to form ssb. An experiment with UV-irradiation, which was likely to induce ssb at the modified region, supported the possibility of DNA modification by DMAA exposure. An ESR study indicated that O2- produced by paraquat in DMAA-exposed cells was more consumed than in non-exposed cells, assumingly through the reaction with the dimethylarsenic-modified region of DNA. The species of active oxygens were estimated by using diethyldithiocarbamate, aminotriazole, diethylmaleate, hydrogen peroxide (H2O2), gamma-irradiation and ethanol. O2- but neither H2O2 nor hydroxyl radicals was very likely to contribute to the ssb-enhancing action of paraquat. PMID:7735248

  7. Arsenic Methyltransferase

    EPA Science Inventory

    The metalloid arsenic enters the environment by natural processes (volcanic activity, weathering of rocks) and by human activity (mining, smelting, herbicides and pesticides). Although arsenic has been exploited for homicidal and suicidal purposes since antiquity, its significan...

  8. Enhanced Adsorption of Trivalent Arsenic from Water by Functionalized Diatom Silica Shells

    PubMed Central

    Zhang, Zhijian; Xu, Liping; Zhang, Chunlong

    2015-01-01

    The potential of porous diatom silica shells as a naturally abundant low-cost sorbent for the removal of arsenic in aqueous solutions was investigated in a batch study. The objective of this work was to chemically modify the silica shells of a diatom Melosira sp. with bifunctional (thiol and amino) groups to effectively remove arsenic in its toxic As(III) form (arsenite) predominant in the aquatic environment. Sorption experiments with this novel sorbent were conducted under varying conditions of pH, time, dosage, and As(III) concentration. A maximum adsorption capacity of 10.99 mg g-1 was achieved within 26 h for a solution containing 12 mg L-1 As(III) at pH 4 and sorbent dosage of 2 g L-1. The functionalized diatom silica shells had a surface morphological change which was accompanied by increased pore size at the expense of reduced specific surface area and total pore volume. As(III) adsorption was best fitted with the Langmuir-Freundlich model, and the adsorption kinetic data using pore surface diffusion model showed that both the external (film) and internal (intraparticle) diffusion can be rate-determining for As(III) adsorption. Fourier transform infrared spectroscopy (FTIR) indicated that the thiol and amino groups potentially responsible for As(III) adsorption were grafted on the surface of diatom silica shells. X-ray photoelectron spectroscopy (XPS) further verified that this unique sorbent proceeded via a chemisorption mechanism through the exchange between oxygen-containing groups of neutral As(III) and thiol groups, and through the surface complexation between As(III) and protonated nitrogen and hydroxyl groups. Results indicate that this functionalized bioadsorbent with a high As(III) adsorption capacity holds promise for the treatment of As(III) containing wastewater. PMID:25837498

  9. Enhanced adsorption of trivalent arsenic from water by functionalized diatom silica shells.

    PubMed

    Zhang, Jianying; Ding, Tengda; Zhang, Zhijian; Xu, Liping; Zhang, Chunlong

    2015-01-01

    The potential of porous diatom silica shells as a naturally abundant low-cost sorbent for the removal of arsenic in aqueous solutions was investigated in a batch study. The objective of this work was to chemically modify the silica shells of a diatom Melosira sp. with bifunctional (thiol and amino) groups to effectively remove arsenic in its toxic As(III) form (arsenite) predominant in the aquatic environment. Sorption experiments with this novel sorbent were conducted under varying conditions of pH, time, dosage, and As(III) concentration. A maximum adsorption capacity of 10.99 mg g-1 was achieved within 26 h for a solution containing 12 mg L-1 As(III) at pH 4 and sorbent dosage of 2 g L-1. The functionalized diatom silica shells had a surface morphological change which was accompanied by increased pore size at the expense of reduced specific surface area and total pore volume. As(III) adsorption was best fitted with the Langmuir-Freundlich model, and the adsorption kinetic data using pore surface diffusion model showed that both the external (film) and internal (intraparticle) diffusion can be rate-determining for As(III) adsorption. Fourier transform infrared spectroscopy (FTIR) indicated that the thiol and amino groups potentially responsible for As(III) adsorption were grafted on the surface of diatom silica shells. X-ray photoelectron spectroscopy (XPS) further verified that this unique sorbent proceeded via a chemisorption mechanism through the exchange between oxygen-containing groups of neutral As(III) and thiol groups, and through the surface complexation between As(III) and protonated nitrogen and hydroxyl groups. Results indicate that this functionalized bioadsorbent with a high As(III) adsorption capacity holds promise for the treatment of As(III) containing wastewater. PMID:25837498

  10. Cancer in Experimental Animals Exposed to Arsenic and Arsenic Compounds

    PubMed Central

    Tokar, Erik J.; Benbrahim-Tallaa, Lamia; Ward, Jerold M.; Lunn, Ruth; Sams, Reeder L.; Waalkes, Michael P.

    2011-01-01

    Inorganic arsenic is a ubiquitous environmental contaminant that has long been considered a human carcinogen. Recent studies raise further concern about the metalloid as a major, naturally occurring carcinogen in the environment. However, during this same period it has proven difficult to provide experimental evidence of the carcinogenicity of inorganic arsenic in laboratory animals and, until recently, there was considered to be a lack of clear evidence for carcinogenicity of any arsenical in animals. More recent work with arsenical methylation metabolites and early life exposures to inorganic arsenic has now provided evidence of carcinogenicity in rodents. Given that tens of millions of people worldwide are exposed to potentially unhealthy levels of environmental arsenic, in vivo rodent models of arsenic carcinogenesis are a clear necessity for resolving critical issues, like mechanisms of action, target tissue specificity, and sensitive subpopulations, and in developing strategies to reduce cancers in exposed human populations. This work reviews the available rodent studies considered relevant to carcinogenic assessment of arsenicals, taking advantage of the most recent review by the International Agency for Research on Cancer (IARC) that has not yet appeared as a full monograph but has been summarized (IARC 2009). Many valid studies show that arsenic can interact with other carcinogens/agents to enhance oncogenesis, and help elucidate mechanisms, and these too are summarized in this review. Finally, this body of rodent work is discussed in light of its impact on mechanisms and in the context of the persistent argument that arsenic is not carcinogenic in animals. PMID:20812815

  11. ARSENIC REMOVAL

    EPA Science Inventory

    Presentation covered five topics; arsenic chemistry, best available technology (BAT), surface water technology, ground water technology and case studies of arsenic removal. The discussion on arsenic chemistry focused on the need and method of speciation for AsIII and AsV. BAT me...

  12. Enhanced suppression of tumor growth by concomitant treatment of human lung cancer cells with suberoylanilide hydroxamic acid and arsenic trioxide

    SciTech Connect

    Chien, Chia-Wen; Yao, Ju-Hsien; Chang, Shih-Yu; Lee, Pei-Chih; Lee, Te-Chang

    2011-11-15

    The efficacy of arsenic trioxide (ATO) against acute promyelocytic leukemia (APL) and relapsed APL has been well documented. ATO may cause DNA damage by generating reactive oxygen intermediates. Suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, modulates gene and protein expression via histone-dependent or -independent pathways that may result in chromatin decondensation, cell cycle arrest, differentiation, and apoptosis. We investigated whether ATO and SAHA act synergistically to enhance the death of cancer cells. Our current findings showed that combined treatment with ATO and SAHA resulted in enhanced suppression of non-small-cell lung carcinoma in vitro in H1299 cells and in vivo in a xenograft mouse model. Flow cytometric analysis of annexin V+ cells showed that apoptotic cell death was significantly enhanced after combined treatment with ATO and SAHA. At the doses used, ATO did not interfere with cell cycle progression, but SAHA induced p21 expression and led to G1 arrest. A Comet assay demonstrated that ATO, but not SAHA, induced DNA strand breaks in H1299 cells; however, co-treatment with SAHA significantly increased ATO-induced DNA damage. Moreover, SAHA enhanced acetylation of histone H3 and sensitized genomic DNA to DNase I digestion. Our results suggest that SAHA may cause chromatin relaxation and increase cellular susceptibility to ATO-induced DNA damage. Combined administration of SAHA and ATO may be an effective approach to the treatment of lung cancer. -- Highlights: Black-Right-Pointing-Pointer ATO and SAHA are therapeutic agents with different action modes. Black-Right-Pointing-Pointer Combination of ATO and SAHA synergistically inhibits tumor cell growth. Black-Right-Pointing-Pointer SAHA loosens chromatin structure resulting in increased sensitivity to DNase I. Black-Right-Pointing-Pointer ATO-induced DNA damage and apoptosis are enhanced by co-treatment with SAHA.

  13. THE CHARACTERIZATION AND IMPLEMENTATION OF AN ENHANCED ACTIVATED ALUMINA FOR THE REMOVAL OF DISSOLVED ARSENIC AT THE POINT OF ENTRY

    EPA Science Inventory

    Technical Challenge: Nearly 5.5% of the water systems in the United States are expected to exceed the new 10 ppb arsenic maximum contaminant level. Many of these systems are in small communities that require an affordable means of meeting these arsenic standards. ...

  14. Cytotoxicity of arsenic trioxide is enhanced by (-)-epigallocatechin-3-gallate via suppression of ferritin in cancer cells

    SciTech Connect

    Lee, Te-Chang; Cheng, I-Cheng; Shue, Jun-Jie; Wang, T.C.

    2011-01-01

    Arsenic trioxide (ATO) treatment is a useful therapy against human acute promyelocytic leukemia (APL), however, it concomitantly brings potential adverse consequences including serious side effect, human carcinogenicity and possible development of resistance. This investigation revealed that those problems might be relaxed by simultaneous application with (-)-epigallocatechin-3-gallate (EGCG), one of the major components from green tea. EGCG significantly lowered down the ATO concentration required for an effective control of APL cells, HL-60. The simultaneous treatment of ATO with EGCG induced a mitochondria-dependent apoptosis in HL-60 cells significantly, which accounted for more than 70% of the cell death in the treatment. The mechanism of apoptosis induction was elucidated. EGCG in HL-60 cells acted as a pro-oxidant enhancing intracellular hydrogen peroxide significantly. ATO, on the other hand, induced heme oxygenase-1 (HO-1) to catalyze heme degradation, thereby provided ferrous iron for EGCG-induced hydrogen peroxide to precede Fenton reaction, which in turn generated deleterious reactive oxygen species to damage cell. In addition, EGCG inhibited expression of ferritin, which supposedly to sequester harmful ferrous iron, thereby augmented the occurrence of Fenton reaction. This investigation also provided evidence that ATO, since mainly acted to induce HO-1 in simultaneous treatment with EGCG, could be replaced by other HO-1 inducer with much less human toxicity. Furthermore, several of our preliminary investigations revealed that the enhanced cytotoxicity induced by combining heme degradation and Fenton reaction is selectively toxic to malignant but not non-malignant cells.

  15. Red mud (RM)-Induced enhancement of iron plaque formation reduces arsenic and metal accumulation in two wetland plant species.

    PubMed

    Yang, J X; Guo, Q J; Yang, J; Zhou, X Y; Ren, H Y; Zhang, H Z; Xu, R X; Wang, X D; Peters, M; Zhu, G X; Wei, R F; Tian, L Y; Han, X K

    2016-01-01

    Human activities have resulted in arsenic (As) and heavy metals accumulation in paddy soils in China. Phytoremediation has been suggested as an effective and low-cost method to clean up contaminated soils. A combined soil-sand pot experiment was conducted to investigate the influence of red mud (RM) supply on iron plaque formation and As and heavy metal accumulation in two wetland plant species (Cyperus alternifolius Rottb., Echinodorus amazonicus Rataj), using As and heavy metals polluted paddy soil combined with three rates of RM application (0, 2%, 5%). The results showed that RM supply significantly decreased As and heavy metals accumulation in shoots of the two plants due to the decrease of As and heavy metal availability and the enhancement of the formation of iron plaque on the root surface and in the rhizosphere. Both wetland plants supplied with RM tended to have more Fe plaque, higher As and heavy metals on roots and in their rhizospheres, and were more tolerant of As and heavy metal toxicity. The results suggest that RM-induced enhancement of the formation of iron plaque on the root surface and in the rhizosphere of wetland plants may be significant for remediation of soils contaminated with As and heavy metals. PMID:26505322

  16. Arsenic enhanced plant growth and altered rhizosphere characteristics of hyperaccumulator Pteris vittata.

    PubMed

    Xu, Jia Yi; Li, Hong Bo; Liang, Shuang; Luo, Jun; Ma, Lena Q

    2014-11-01

    We investigated the effects of arsenic species on As accumulation, plant growth and rhizospheric changes in As-hyperaccumulator Pteris vittata (PV). PV was grown for 60-d in a soil spiked with 200 mg kg(-1) arsenate (AsV-soil) or arsenite (AsIII-soil). Diffusive gradients in thin-films technique (DGT) were used to monitor As uptake by PV. Interestingly AsIII-soil produced the highest PV biomass at 8.6 g plant(-1), 27% and 46% greater than AsV-soil and the control. Biomass increase was associated with As-induced P uptake by PV. Although AsIII was oxidized to AsV during the experiment, As species impacted As accumulation by PV, with 17.5% more As in AsIII-soil than AsV-soil (36 vs. 31 mg plant(-1)). As concentration in PV roots was 30% higher in AsV-soil whereas As concentration in PV fronds was 7.9% greater in AsIII-soil, suggesting more rapid translocation of AsIII than AsV. These findings were important to understand the mechanisms of As uptake, accumulation and translocation by PV. PMID:25103044

  17. Microbial Sulfate Reduction Enhances Arsenic Mobility Downstream of Zerovalent-Iron-Based Permeable Reactive Barrier.

    PubMed

    Kumar, Naresh; Couture, Raoul-Marie; Millot, Romain; Battaglia-Brunet, Fabienne; Rose, Jérôme

    2016-07-19

    We assessed the potential of zerovalent-iron- (Fe(0)) based permeable reactive barrier (PRB) systems for arsenic (As) remediation in the presence or absence of microbial sulfate reduction. We conducted long-term (200 day) flow-through column experiments to investigate the mechanisms of As transformation and mobility in aquifer sediment (in particular, the PRB downstream linkage). Changes in As speciation in the aqueous phase were monitored continuously. Speciation in the solid phase was determined at the end of the experiment using X-ray absorption near-edge structure (XANES) spectroscopy analysis. We identified thio-As species in solution and AsS in solid phase, which suggests that the As(V) was reduced to As(III) and precipitated as AsS under sulfate-reducing conditions and remained as As(V) under abiotic conditions, even with low redox potential and high Fe(II) content (4.5 mM). Our results suggest that the microbial sulfate reduction plays a key role in the mobilization of As from Fe-rich aquifer sediment under anoxic conditions. Furthermore, they illustrate that the upstream-downstream linkage of PRB affects the speciation and mobility of As in downstream aquifer sediment, where up to 47% of total As initially present in the sediment was leached out in the form of mobile thio-As species. PMID:27309856

  18. Enhanced arsenic removals through plant interactions in subsurface-flow constructed wetlands.

    PubMed

    Singhakant, Chatchawal; Koottatep, Thammarat; Satayavivad, Jutamaad

    2009-02-01

    Arsenic (As) removal in pilot-scale subsurface-flow constructed wetlands (CWs) was investigated by comparing between CW units with vetiver grasses (CWplanted) and CW units without vetiver grasses (CWunplanted) in order to determine the roles of vetiver grasses affecting As removal. Based on the data obtained from 147 days of experiment, it is apparent that CWplanted units could remove As significantly higher than those of CWunplanted units with approximately 7-14%. Although analysis of As mass balance in CW units revealed that only 0.5-1.0% of total As was found in vetiver grasses, the As retained within bed of the CWplanted units (23.6-29.7 g) was higher than those in the CWunplanted units (21.3-26.8 g) at the end of the experiment, illustrating the effect of vetiver grasses on As accumulation in the CW units. Determination of As in different fractions in the CW bed suggested that the main mechanism of As retention was due mainly to As entrapment into the porous of bed materials (50-57% of total fraction), this mechanism is likely not affected by the presence of vetiver grasses. However, fraction of As-bound in organic matters that could be released from plant roots decomposition indicated the increase adsorption capacity of CW bed. In addition, organic sulfides produced from their root decomposition could help remove As through the precipitation/co-precipitation process. Under reducing condition in those CWplanted units, As could be leached out in the form of iron and manganese-bound complexes. PMID:19123096

  19. Method of removing arsenic and other anionic contaminants from contaminated water using enhanced coagulation

    DOEpatents

    Teter, David M.; Brady, Patrick V.; Krumhansl, James L.; Khandaker, Nadim R.

    2006-11-21

    An improved water decontamination process comprising contacting water containing anionic contaminants with an enhanced coagulant to form an enhanced floc, which more efficiently binds anionic species (e.g., arsenate, arsenite, chromate, fluoride, selenate, and borate, and combinations thereof) predominantly through the formation of surface complexes. The enhanced coagulant comprises a trivalent metal cation coagulant (e.g., ferric chloride or aluminum sulfate) mixed with a divalent metal cation modifier (e.g., copper sulfate or zinc sulfate).

  20. Arsenic trioxide enhances the cytotoxic effect of cisplatin in head and neck squamous cell carcinoma cell lines

    PubMed Central

    KOTOWSKI, ULANA; HEIDUSCHKA, GREGOR; BRUNNER, MARKUS; EROVIC, BOBAN M.; MARTINEK, HELGA; THURNHER, DIETMAR

    2012-01-01

    Arsenic trioxide (ATO) has been approved for the treatment of relapsed acute promyelocytic leukaemia. The aim of this study was to determine whether ATO would lead to cell death in head and neck squamous cell carcinoma (HNSCC) cell lines and whether it was able to enhance the cytotoxicity of cisplatin, a standard chemotherapeutic agent. The four HNSCC cell lines SCC9, SCC25, CAL27 and FADU were treated with ATO or cisplatin alone or with ATO and cisplatin in combination. Cytotoxicity assays, immunohistochemistry, western blot analysis and flow cytometry were carried out. Possible interactions between the two drugs were calculated using the Chou-Talalay equation. Ther results demonstrated a synergistic cytotoxic effect of the combination of ATO and cisplatin at high doses. The two agents induced apoptosis in all four HNSCC cell lines. In conclusion, this study showed that ATO is a promising therapeutic drug with cytotoxic effects in HNSCC. We demonstrated a synergistic effect in the combined treatment with cisplatin at high doses. PMID:22783443

  1. Enhanced arsenic removal by in situ formed Fe-Mn binary oxide in the aeration-direct filtration process.

    PubMed

    Wu, Kun; Liu, Rui-Ping; Liu, Hui-Juan; Lan, Hua-Chun; Qu, Jiu-Hui

    2012-11-15

    Field studies were conducted to evaluate the feasibility of an in situ formed Fe-Mn binary oxide (in situ FMBO) for improving arsenic (As) removal in the aeration-direct filtration process. The transformation and transportation of As, Fe, and Mn in the filter bed were also investigated. The in situ FMBO increased the As removal efficiency by 20-50% to keep the residual As below 10 μg/L. The optimum FMBO dosage was determined to be 0.55 mg/L with the Fe/Mn ratio as 10:1. The removal of Fe, Mn, turbidity, and particles was also improved to a large extent. The in situ FMBO favored the transformation of soluble As, Fe, and Mn into the solid phases, benefiting the removal of these pollutants by the subsequent filtration. Moreover, the deposited precipitates onto the filter media were characterized, as indicated by the analyses of SEM/EDS and particle size distribution. The long-term experiments exhibited decreased head loss growth and prolonged run length, suggesting an enhanced pollutant catching capacity of the filter media. The full-scale field study with a flow of 10,000 m3/d confirmed positive effects of in situ FMBO on As removal, with the average effluent As concentration reduced from 20 μg/L to 6 μg/L (reagent cost=0.006 ¥/m3). PMID:23017236

  2. Enhanced Removal of Arsenic and Antimony in the Mining Site by Calcined γ-Fe2O3/Layered Double Hydroxide Nanocomposite

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Ho; Choi, Heechul; Kim, Kyoung-Woong

    2016-04-01

    Arsenic (As) and Antimony (Sb) have been recognized as harmful contaminants in aquatic environment due to its high toxicity and carcinogenicity. Especially, the contamination of arsenic in the mining areas is considered as a serious emerging environmental issue in Korea. Due to the hazardous effect of arsenic, the United States Environmental Protection Agency (US EPA) regulated maximum contamination level of arsenic to 10 μg/L in drinking water. The harmful effect on human health by excessive intake of antimony was also reported by previous studies, and severe contamination level (100 - 7,000 μg/L) of antimony reported in surface and groundwater of abandoned mining area in China and Slovakia. Therefore, US EPA regulated maximum contaminants level of antimony in drinking water to 6 μg/L. In order to remove anionic contaminants in drinking water, various type of nanomaterials have been developed. Layered double hydroxide (LDH) is the artificial anionic clay that is based on the layered structure of positively charged brucite-like layers with interlayers of anions. The LDH is one of the promising nanomaterials for the removal of anionic contaminants because it has high selectivity for arsenic, phosphate, chromium and antimony. However, the biggest problem of LDH for wastewater treatment is that the particles cannot be easily separated after the removal of contaminants. In this study, magnetic nanoparticles (γ-Fe2O3) supported LDH nanocomposite (γ-Fe2O3/LDH) was investigated to enhance magnetic particle recovery and removal efficiency for arsenic and antimony. The calcined γ-Fe2O3/LDH nanocomposites synthesized by co-precipitation method, and the crystallographic properties of maghemite (γ-Fe2O3) and layered structure of LDH were confirmed by X-ray diffraction. The nano-sized γ-Fe2O3 (30 to 50 nm) was stably attached on the surface of LDH (100 to 150 nm) and O1s spectrum by X-ray photoelectron spectroscopy (XPS) explained that there are both physical and

  3. A Phytoremediation Strategy for Arsenic

    SciTech Connect

    Meagher, Richard B.

    2005-06-01

    A Phytoremediation Strategy for Arsenic Progress Report May, 2005 Richard B. Meagher Principal Investigator Arsenic pollution affects the health of several hundred millions of people world wide, and an estimated 10 million Americans have unsafe levels of arsenic in their drinking water. However, few environmentally sound remedies for cleaning up arsenic contaminated soil and water have been proposed. Phytoremediation, the use of plants to extract and sequester environmental pollutants, is one new technology that offers an ecologically sound solution to a devastating problem. We propose that it is less disruptive to the environment to harvest and dispose of several thousand pounds per acre of contaminated aboveground plant material, than to excavate and dispose of 1 to 5 million pounds of contaminated soil per acre (assumes contamination runs 3 ft deep). Our objective is to develop a genetics-based phytoremediation strategy for arsenic removal that can be used in any plant species. This strategy requires the enhanced expression of several transgenes from diverse sources. Our working hypothesis is that organ-specific expression of several genes controlling the transport, electrochemical state, and binding of arsenic will result in the efficient extraction and hyperaccumulation of arsenic into aboveground plant tissues. This hypothesis is supported by theoretical arguments and strong preliminary data. We proposed six Specific Aims focused on testing and developing this arsenic phytoremediation strategy. During the first 18 months of the grant we made significant progress on five Specific Aims and began work on the sixth as summarized below. Specific Aim 1: Enhance plant arsenic resistance and greatly expand sinks for arsenite by expressing elevated levels of thiol-rich, arsenic-binding peptides. Hyperaccumulation of arsenic depends upon making plants that are both highly tolerant to arsenic and that have the capacity to store large amounts of arsenic aboveground

  4. Arsenic induces NAD(P)H-quinone oxidoreductase I by disrupting the Nrf2 x Keap1 x Cul3 complex and recruiting Nrf2 x Maf to the antioxidant response element enhancer.

    PubMed

    He, Xiaoqing; Chen, Michael G; Lin, Gary X; Ma, Qiang

    2006-08-18

    The ubiquitous toxic metalloid arsenic elicits pleiotropic adverse and adaptive responses in mammalian species. The biological targets of arsenic are largely unknown at present. We analyzed the signaling pathway for induction of detoxification gene NAD(P)H-quinone oxidoreductase (Nqo1) by arsenic. Genetic and biochemical evidence revealed that induction required cap 'n' collar basic leucine zipper transcription factor Nrf2 and the antioxidant response element (ARE) of Nqo1. Arsenic stabilized Nrf2 protein, extending the t(1/2) of Nrf2 from 21 to 200 min by inhibiting the Keap1 x Cul3-dependent ubiquitination and proteasomal turnover of Nrf2. Arsenic markedly inhibited the ubiquitination of Nrf2 but did not disrupt the Nrf2 x Keap1 x Cul3 association in the cytoplasm. In the nucleus, arsenic, but not phenolic antioxidant tert-butylhydroquinone, dissociated Nrf2 from Keap1 and Cul3 followed by dimerization of Nrf2 with a Maf protein (Maf G/Maf K). Chromatin immunoprecipitation demonstrated that Nrf2 and Maf associated with the endogenous Nqo1 ARE enhancer constitutively. Arsenic substantially increased the ARE occupancy by Nrf2 and Maf. In addition, Keap1 was shown to be ubiquitinated in the cytoplasm and deubiquitinated in the nucleus in the presence of arsenic without changing the protein level, implicating nuclear-cytoplasmic recycling of Keap1. Our data reveal that arsenic activates the Nrf2/Keap1 signaling pathway through a distinct mechanism from that by antioxidants and suggest an "on-switch" model of Nqo1 transcription in which the binding of Nrf2 x Maf to ARE controls both the basal and inducible expression of Nqo1. PMID:16785233

  5. Arsenic-induced enhancement of ultraviolet radiation carcinogenesis in mouse skin: a dose-response study.

    PubMed Central

    Burns, Fredric J; Uddin, Ahmed N; Wu, Feng; Nádas, Arthur; Rossman, Toby G

    2004-01-01

    The present study was designed to establish the form of the dose-response relationship for dietary sodium arsenite as a co-carcinogen with ultraviolet radiation (UVR) in a mouse skin model. Hairless mice (strain Skh1) were fed sodium arsenite continuously in drinking water starting at 21 days of age at concentrations of 0.0, 1.25, 2.5, 5.0, and 10 mg/L. At 42 days of age, solar spectrum UVR exposures were applied three times weekly to the dorsal skin at 1.0 kJ/m2 per exposure until the experiment ended at 182 days. Untreated mice and mice fed only arsenite developed no tumors. In the remaining groups a total of 322 locally invasive squamous carcinomas occurred. The carcinoma yield in mice exposed only to UVR was 2.4 +/- 0.5 cancers/mouse at 182 days. Dietary arsenite markedly enhanced the UVR-induced cancer yield in a pattern consistent with linearity up to a peak of 11.1 +/- 1.0 cancers/mouse at 5.0 mg/L arsenite, representing a peak enhancement ratio of 4.63 +/- 1.05. A decline occurred to 6.8 +/- 0.8 cancers/mouse at 10.0 mg/L arsenite. New cancer rates exhibited a consistent-with-linear dependence on time beginning after initial cancer-free intervals ranging between 88 and 95 days. Epidermal hyperplasia was elevated by arsenite alone and UVR alone and was greater than additive for the combined exposures as were growth rates of the cancers. These results demonstrate the usefulness of a new animal model for studying the carcinogenic action of dietary arsenite on skin exposed to UVR and should contribute to understanding how to make use of animal data for assessment of human cancer risks in tissues exposed to mixtures of carcinogens and cancer-enhancing agents. PMID:15064167

  6. Enhanced and Stabilized Arsenic Retention in Microcosms through the Microbial Oxidation of Ferrous Iron by Nitrate

    PubMed Central

    SUN, JING; CHILLRUD, STEVEN N.; MAILLOUX, BRIAN J.; STUTE, MARTIN; SINGH, RAJESH; DONG, HAILIANG; LEPRE, CHRISTOPHER J.; BOSTICK, BENJAMIN C.

    2016-01-01

    Magnetite strongly retains As, and is relatively stable under Fe(III)-reducing conditions common in aquifers that release As. Here, laboratory microcosm experiments were conducted to investigate a potential As remediation method involving magnetite formation, using groundwater and sediments from the Vineland Superfund site. The microcosms were amended with various combinations of nitrate, Fe(II)(aq)(as ferrous sulfate) and lactate, and were incubated for more than 5 weeks. In the microcosms enriched with 10 mM nitrate and 5 mM Fe(II)(aq), black magnetic particles were produced, and As removal from solution was observed even under sustained Fe(III) reduction stimulated by the addition of 10 mM lactate. The enhanced As retention was mainly attributed to co-precipitation within magnetite and adsorption on a mixture of magnetite and ferrihydrite. Sequential chemical extraction, X-ray absorption spectroscopy and magnetic susceptibility measurements showed that these minerals formed at pH 6 – 7 following nitrate-Fe(II) addition, and As-bearing magnetite was stable under reducing conditions. Scanning electron microscopy and X-ray diffraction indicated that nano-particulate magnetite was produced as coatings on fine sediments, and no aging effect was detected on morphology over the course of incubation. These results suggest that a magnetite based strategy may be a long-term remedial option for As-contaminated aquifers. PMID:26454120

  7. Enhanced and stabilized arsenic retention in microcosms through the microbial oxidation of ferrous iron by nitrate.

    PubMed

    Sun, Jing; Chillrud, Steven N; Mailloux, Brian J; Stute, Martin; Singh, Rajesh; Dong, Hailiang; Lepre, Christopher J; Bostick, Benjamin C

    2016-02-01

    Magnetite strongly retains As, and is relatively stable under Fe(III)-reducing conditions common in aquifers that release As. Here, laboratory microcosm experiments were conducted to investigate a potential As remediation method involving magnetite formation, using groundwater and sediments from the Vineland Superfund site. The microcosms were amended with various combinations of nitrate, Fe(II) (aq) (as ferrous sulfate) and lactate, and were incubated for more than 5 weeks. In the microcosms enriched with 10 mM nitrate and 5 mM Fe(II) (aq), black magnetic particles were produced, and As removal from solution was observed even under sustained Fe(III) reduction stimulated by the addition of 10 mM lactate. The enhanced As retention was mainly attributed to co-precipitation within magnetite and adsorption on a mixture of magnetite and ferrihydrite. Sequential chemical extraction, X-ray absorption spectroscopy and magnetic susceptibility measurements showed that these minerals formed at pH 6-7 following nitrate-Fe(II) addition, and As-bearing magnetite was stable under reducing conditions. Scanning electron microscopy and X-ray diffraction indicated that nano-particulate magnetite was produced as coatings on fine sediments, and no aging effect was detected on morphology over the course of incubation. These results suggest that a magnetite based strategy may be a long-term remedial option for As-contaminated aquifers. PMID:26454120

  8. Microbes Enhanced Mobility of Arsenic, without Iron Reduction in Deep Bangladesh Aquifer

    NASA Astrophysics Data System (ADS)

    Dhar, R. K.; Zheng, Y.; Saltikov, C. W.; Radloff, K. A.; Mailloux, B.; van Geen, A.

    2008-12-01

    The role of microbial arsenate and iron reduction in As mobilization can be difficult to distinguish. A set of incubation experiments was conducted anaerobically over 3 months using deep Pleistocene (orange) aquifer sands from Bangladesh containing low HCl-leachable Fe(II)/Fe of 0.05 and phosphate-extractable As of 0.14 mg/kg, all as arsenate. The experiments assess the role of microbial reduction in a setting of great practical importance because the deep Pleistocene aquifer is a viable source of drinking water for Bangladesh where shallow Holocene aquifers often exceed 50 ìg/L of As. Sands, resuspended in artificial groundwater(Agw) were inoculated with wild-type Shewanella sp. ANA-3, capable of Fe(III), Mn(IV), As(V) reduction. The equivalent of 0.035 mg/kg sedimentary As was mobilized on day 23 by this strain. The controls with or without lactate and without strain of Shewanella released less than the equivalent of 0.003 mg/kg As from the solid phase. We observed that As release was limited by microbes with or without lactate whereas Fe and Mn release was limited by lactate. The reduction of Fe do not enhance the As release. Furthermore, Shewanella sp. ANA-3 strain significantly converted the solid phase As to a mobilizable form by 92 days. Microbial processes responsible for this conversion may therefore be the critical process to evaluate to assess the vulnerability of Pleistocene aquifers of Bangladesh.

  9. Enhancement of arsenic adsorption during mineral transformation from siderite to goethite: mechanism and application.

    PubMed

    Guo, Huaming; Ren, Yan; Liu, Qiong; Zhao, Kai; Li, Yuan

    2013-01-15

    Synthesized siderite was used to remove As(III) and As(V) from water solutions under anoxic conditions and oxic conditions. Results showed that As adsorption on synthetic siderite under anoxic conditions was around 10 mg/g calculated with Langmuir isotherm. However, the calculated As adsorption on synthetic siderite under oxic conditions ranged between 115 and 121 mg/g, which was around 11 times higher than that under anoxic conditions. It was found that 75% siderite was transformed into goethite during oxic adsorption. However, synthetic goethite had lower As adsorption capacity than siderite under oxic conditions, although its adsorption capacity was a little higher than siderite under anoxic conditions. It suggested that the coexistence of goethite and siderite bimineral during mineral transformation probably contributed to the robust adsorption capacity of siderite under oxic conditions. Results of extended X-ray absorption fine structure (EXAF) spectroscopy indicated both As(III) and As(V) formed inner-sphere complexes on the surface of As-treated solid regardless of substrates, including the bidentate binuclear corner-sharing ((2)C) complexes and the monodentate mononuclear corner-sharing ((1)V) complexes. Monodenate ((1)V) and bidentate ((2)C) complexes would be related to high As adsorption capacity of siderite under oxic conditions. It showed that more Fe atoms were coordinated with As atom in the monodentate complexes and the bidentate complexes of As(V)/As(III)-treated siderite under oxic conditions, in comparison with As(V)/As(III)-treated siderite under anoxic conditions and As(V)/As(III)-treated goethite. Calcinations of natural siderite resulting in the coexistence of goethite and siderite greatly increased As adsorption on the solid, which confirmed that the coexistence of bimineral during mineral transformation from siderite to goethite greatly enhanced As adsorption capacity of siderite adsorbent. The observation can be applied for modification of

  10. Using a Solid Oxidizing Media to Enhance Arsenic (As[III]) Removal at a Very Small System

    EPA Science Inventory

    An adsorptive media system at the LEADS Head Start School (LHSS) Building in Buckeye Lake, OH, one of the 50 U.S. EPA Arsenic Removal Technology Demonstration sites, was relocated, after modifications, to Plainview Christian School in Plain City, OH to help bring the non-transien...

  11. Ferric ion induced enhancement of ultraviolet vapour generation coupled with atomic fluorescence spectrometry for the determination of ultratrace inorganic arsenic in surface water.

    PubMed

    Wang, Yuelong; Lin, Lingling; Liu, Jixin; Mao, Xuefei; Wang, Jianhua; Qin, Deyuan

    2016-02-21

    A novel method of ultraviolet vapour generation (UVG) coupled with atomic fluorescence spectrometry (AFS) was developed for the determination of ultratrace inorganic arsenic (iAs) in surface water. In this work, different ferric species were utilised for the first time as an enhancement reagent for the ultraviolet vapour generation of As(III), and their UVG efficiencies for volatile species of arsenic were investigated. 15 mg L(-1) of ferric chloride provided the greatest enhancement of approximately 10-fold, using 20% acetic acid combined with 4% formic acid with 30 s ultraviolet irradiation at 200 mL min(-1) Ar/H2 flow rate. Under the optimised conditions, the linear range was 1.0 μg L(-1)-100.0 μg L(-1), and the spiked recoveries were 92%-98%. The limit of detection was 0.05 μg L(-1) for iAs, and the relative standard deviation (RSD) value of the repeated measurements was 2.0% (n = 11). This method was successfully applied to the determination of ultratrace iAs in tap water, river water, and lake water samples using 0.2% H2SO4 (v : v) as the sample preserver. The obtained values for the water samples of certified reference materials (CRMs) including GSB-Z50004-200431, GBW08605 and GBW(E)080390 were all within the certified ranges. PMID:26765360

  12. Arsenic-resistant bacteria solubilized arsenic in the growth media and increased growth of arsenic hyperaccumulator Pteris vittata L.

    PubMed

    Ghosh, Piyasa; Rathinasabapathi, Bala; Ma, Lena Q

    2011-10-01

    The role of arsenic-resistant bacteria (ARB) in arsenic solubilization from growth media and growth enhancement of arsenic-hyperaccumulator Pteris vittata L. was examined. Seven ARB (tolerant to 10 mM arsenate) were isolated from the P. vittata rhizosphere and identified by 16S rRNA sequencing as Pseudomonas sp., Comamonas sp. and Stenotrophomonas sp. During 7-d hydroponic experiments, these bacteria effectively solubilized arsenic from the growth media spiked with insoluble FeAsO₄ and AlAsO₄ minerals (from < 5 μg L⁻¹ to 5.04-7.37 mg L⁻¹ As) and enhanced plant arsenic uptake (from 18.1-21.9 to 35.3-236 mg kg⁻¹ As in the fronds). Production of (1) pyochelin-type siderophores by ARB (fluorescent under ultraviolet illumination and characterized with thin layer chromatography) and (2) root exudate (dissolved organic C) by P. vittata may be responsible for As solubilization. Increase in P. vittata root biomass from 1.5-2.2 to 3.4-4.2 g/plant dw by ARB and by arsenic was associated with arsenic-induced plant P uptake. Arsenic resistant bacteria may have potential to enhance phytoremediation of arsenic-contaminated soils by P. vittata. PMID:21840210

  13. Enhanced arsenic removal from water by hierarchically porous CeO₂-ZrO₂ nanospheres: role of surface- and structure-dependent properties.

    PubMed

    Xu, Weihong; Wang, Jing; Wang, Lei; Sheng, Guoping; Liu, Jinhuai; Yu, Hanqing; Huang, Xing-Jiu

    2013-09-15

    Arsenic contaminated natural water is commonly used as drinking water source in some districts of Asia. To meet the increasingly strict drinking water standards, exploration of efficient arsenic removal methods is highly desired. In this study, hierarchically porous CeO₂-ZrO₂ nanospheres were synthesized, and their suitability as arsenic sorbents was examined. The CeO₂-ZrO₂ hollow nanospheres showed an adsorption capacity of 27.1 and 9.2 mg g(-1) for As(V) and As(III), respectively, at an equilibrium arsenic concentration of 0.01 mg L(-1) (the standard for drinking water) under neutral conditions, indicating a high arsenic removal performance of the adsorbent at low arsenic concentrations. Such a great arsenic adsorption capacity was attributed to the high surface hydroxyl density and presence of hierarchically porous network in the hollow nanospheres. The analysis of Fourier transformed infrared spectra and X-ray photoelectron spectroscopy demonstrated that the adsorption of arsenic on the CeO₂-ZrO₂ nanospheres was completed through the formation of a surface complex by substituting hydroxyl with arsenic species. In addition, the CeO₂-ZrO₂ nanospheres were able to remove over 97% arsenic in real underground water with initial arsenic concentration of 0.376 mg L(-1) to meet the guideline limit of arsenic in drinking water regulated by the World Health Organization without any pre-treatment and/or pH adjustment. PMID:23811372

  14. Arsenic Trioxide (ATO) cooperates with All Trans Retinoic Acid (ATRA) to enhance MAPK activation and differentiation in Human Myeloblastic Leukemia (HL-60) cells

    PubMed Central

    Nayak, Satyaprakash; Shen, Miaoqing; Varner, Jeffrey D.; Yen, Andrew

    2016-01-01

    Arsenic trioxide (ATO) synergistically promotes retinoic acid (RA)-induced differentiation of HL-60 myeloblastic leukemia cells, a PML-RARα negative cell line. In PML-RARα positive myeloid leukemia cells, ATO is known to cause degradation of PML-RARα with subsequent induced myeloid differentiation. We find now that ATO by itself does not cause differentiation of the PML-RARα negative HL-60 cells, but enhances RA’s capability to cause differentiation. RA-induced differentiation of HL-60 cells is known to be propelled by an induced hyperactive/persistent MAPK signal. ATO augmented RA induced RAF/MEK/ERK axis signaling and expression of CD11b, an integrin receptor that is a myeloid differentiation marker. p47PHOX, a component of the respiratory burst machinery and inducible oxidative metabolism, functional differentiation marker were also enhanced. However, ATO did not enhance RA-induced CD38 expression, an early cell surface differentiation marker. ATO enhanced RA-induced population growth retardation without evidence of apoptosis or an enhanced G1/0 growth arrest. But compared to RA, ATO plus RA showed reduced pAKT, suggesting that an overall biosynthetic/metabolic retardation was seminal to the apparent enhanced growth retardation due to ATO. In sum, our results indicate that ATO can augment action of RA in causing differentiation of myeloid leukemia cells through promoting MAPK signaling and independent of PML-RARα. PMID:20615082

  15. Evaluation of Redox Conditions and Enhanced Arsenic Mobility from Waste Disposal in a Complex Fractured Crystalline-Rock Aquifer, Raymond, New Hampshire, USA (Note: article rewritten under new title)

    EPA Science Inventory

    (Note: This entry is no longer valid; the paper was rewritten and submitted to a different journal.) This paper highlights some methods that can be used at a local scale to assess whether waste disposal activities are responsible for enhanced arsenic mobility through redox-contro...

  16. Arsenic, inorganic

    Integrated Risk Information System (IRIS)

    Arsenic , inorganic ; CASRN 7440 - 38 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  17. Effect of Arsenic on Growth, Arsenic Uptake, Distribution of Nutrient Elements and Thiols in Seedlings of Wrightia arborea (Dennst.) Mabb.

    PubMed

    Kumar, Dharmendra; Singh, Vijay Pratap; Tripathi, Durgesh Kumar; Prasad, Sheo Mohan; Chauhan, Devendra Kumar

    2015-01-01

    Hydroponic experiments were conducted to investigate the effect of arsenic on seedlings of Wrightia arborea and Holoptelea integrifolia. Results revealed that W. arborea could tolerate much higher arsenic concentration than H. integrifolia. Therefore, further investigations were focused on W. arborea using higher arsenic concentrations (0.2-2.0 mM). Seedlings of W. arborea accumulated about 312-2147 and 1048-5688 mg/kg dry weight of arsenic in shoots and roots, respectively, following treatments with 0.2-1.5 mM of arsenic without exhibiting arsenic toxicity signs. However, arsenic at 2.0 mM caused decline in growth. Macronutrients content such as Ca, S (except at 2.0 mM), and K (only in root) increased while Mg, P, and K (shoot) decreased by arsenic treatments. However, the content of micronutrients was enhanced under arsenic treatments. Non-protein thiols (NP-SH) showed positive correlations with arsenic doses up to 0.2-1.5 mM but at 2.0 mM there was a decline in NP-SH thus suggesting important role of NP-SH in imparting arsenic tolerance. This study demonstrated that W. arborea that could tolerate arsenic concentrations up to 0.2-1.5 mM may be useful in arsenic phytoremediation programs. PMID:25237723

  18. Knockdown of TWIST1 enhances arsenic trioxide- and ionizing radiation-induced cell death in lung cancer cells by promoting mitochondrial dysfunction

    SciTech Connect

    Seo, Sung-Keum; Kim, Jae-Hee; Choi, Ha-Na; Choe, Tae-Boo; Hong, Seok-Il; Yi, Jae-Youn; Hwang, Sang-Gu; Lee, Hyun-Gyu; Lee, Yun-Han; Park, In-Chul

    2014-07-11

    Highlights: • Knockdown of TWIST1 enhanced ATO- and IR-induced cell death in NSCLCs. • Intracellular ROS levels were increased in cells treated with TWIST1 siRNA. • TWIST1 siRNA induced MMP loss and mitochondrial fragmentation. • TWIST1 siRNA upregulated the fission-related proteins FIS1 and DRP1. - Abstract: TWIST1 is implicated in the process of epithelial mesenchymal transition, metastasis, stemness, and drug resistance in cancer cells, and therefore is a potential target for cancer therapy. In the present study, we found that knockdown of TWIST1 by small interfering RNA (siRNA) enhanced arsenic trioxide (ATO)- and ionizing radiation (IR)-induced cell death in non-small-cell lung cancer cells. Interestingly, intracellular reactive oxygen species levels were increased in cells treated with TWIST1 siRNA and further increased by co-treatment with ATO or IR. Pretreatment of lung cancer cells with the antioxidant N-acetyl-cysteine markedly suppressed the cell death induced by combined treatment with TWIST1 siRNA and ATO or IR. Moreover, treatment of cells with TWIST1 siRNA induced mitochondrial membrane depolarization and significantly increased mitochondrial fragmentation (fission) and upregulated the fission-related proteins FIS1 and DRP1. Collectively, our results demonstrate that siRNA-mediated TWIST1 knockdown induces mitochondrial dysfunction and enhances IR- and ATO-induced cell death in lung cancer cells.

  19. Expressing ScACR3 in rice enhanced arsenite efflux and reduced arsenic accumulation in rice grains.

    PubMed

    Duan, Guilan; Kamiya, Takehiro; Ishikawa, Satoru; Arao, Tomohito; Fujiwara, Toru

    2012-01-01

    Arsenic (As) accumulation in rice grain poses a serious health risk to populations with high rice consumption. Extrusion of arsenite [As(III)] by ScAcr3p is the major arsenic detoxification mechanism in Saccharomyces cerevisiae. However, ScAcr3p homolog is absent in higher plants, including rice. In this study, ScACR3 was introduced into rice and expressed under the control of the Cauliflower mosaic virus (CaMV) 35S promoter. In the transgenic lines, As concentrations in shoots and roots were about 30% lower than in the wild type, while the As translocation factors were similar between transgenic lines and the wild type. The roots of transgenic plants exhibited significantly higher As efflux activities than those of the wild type. Within 24 h exposure to 10 μM arsenate [As(V)], roots of ScACR3-expressing plants extruded 80% of absorbed As(V) to the external solution as As(III), while roots of the wild type extruded 50% of absorbed As(V). Additionally, by exposing the As-containing rice plants to an As-lacking solution for 24 h, about 30% of the total As derived from pre-treatment was extruded to the external solution by ScACR3-expressing plants, while about 15% of As was extruded by wild-type plants. Importantly, ScACR3 expression significantly reduced As accumulation in rice straws and grains. When grown in flooded soil irrigated with As(III)-containing water, the As concentration in husk and brown rice of the transgenic lines was reduced by 30 and 20%, respectively, compared with the wild type. This study reports a potential strategy to reduce As accumulation in the food chain by expressing heterologous genes in crops. PMID:22107880

  20. Arsenic detection in water: YPO4:Eu3+ nanoparticles

    NASA Astrophysics Data System (ADS)

    Ghosh, Debasish; Luwang, Meitram Niraj

    2015-12-01

    This work reports on the novel technique of detection of arsenic in aqueous solution utilising the luminescence properties of lanthanide doped nanomaterials. Eu3+ (5%) doped YPO4nanorodswere utilised for the said experiment. Co-precipitation method was used for the synthesis of the materials and characterised them with different instrumental techniques like X-ray diffraction (XRD), Infra-red (IR), UV-absorption, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and photoluminescence studies. This nanoparticle can adsorb both arsenic and arsenious acids. We studied the effect of arsenic adsorption on the luminescence behaviour of the nanoparticles. Arsenic acid enhanced the luminescence intensity whereas arsenious acid quenched the luminescence. This luminescence enhancement or quenching is related with arsenic concentration. This relation of luminescence property with concentration of arsenic can be used to detect arsenic in industrial waste.

  1. Arsenic surveillance program

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Background information about arsenic is presented including forms, common sources, and clinical symptoms of arsenic exposure. The purpose of the Arsenic Surveillance Program and LeRC is outlined, and the specifics of the Medical Surveillance Program for Arsenic Exposure at LeRC are discussed.

  2. A novel arsenic methyltransferase gene of Westerdykella aurantiaca isolated from arsenic contaminated soil: phylogenetic, physiological, and biochemical studies and its role in arsenic bioremediation.

    PubMed

    Verma, Shikha; Verma, Pankaj Kumar; Meher, Alok Kumar; Dwivedi, Sanjay; Bansiwal, Amit Kumar; Pande, Veena; Srivastava, Pankaj Kumar; Verma, Praveen Chandra; Tripathi, Rudra Deo; Chakrabarty, Debasis

    2016-03-01

    Elevated arsenic concentration in the environment and agricultural soil is a serious concern to crop production and human health. Among different detoxification mechanisms, the methylation of arsenic is a widespread phenomenon in nature. A number of microorganisms are able to methylate arsenic, but less is known about the arsenic metabolism in fungi. We identified a novel arsenic methyltransferase (WaarsM) gene from a soil fungus, Westerdykella aurantiaca. WaarsM showed sequence homology with all known arsenic methyltransferases having three conserved SAM binding motifs. The expression of WaarsM enhanced arsenic resistance in E. coli (Δars) and S. cerevisiae (Δacr2) strains by biomethylation and required endogenous reductants, preferably GSH, for methyltransferase activity. The purified WaarsM catalyzes the production of methylated arsenicals from both AsIII and AsV, and also displays AsV reductase activity. It displayed higher methyltransferase activity and lower KM 0.1945 ± 0.021 mM and KM 0.4034 ± 0.078 mM for AsIII and AsV, respectively. S. cerevisiae (Δacr2) cells expressing WaarsM produced 2.2 ppm volatile arsenic and 0.64 ppm DMA(v) with 0.58 ppm volatile arsenicals when exposed to 20 ppm AsV and 2 ppm AsIII, respectively. Arsenic tolerance in rice after co-culture with genetically engineered yeast suggested its potential role in arsenic bioremediation. Thus, characterization of WaarsM provides a potential strategy to reduce arsenic concentration in soil with reduced arsenic accumulation in crops grown in arsenic contaminated areas, and thereby alleviating human health risks. PMID:26776948

  3. Earth Abides Arsenic Biotransformations

    PubMed Central

    Zhu, Yong-Guan; Yoshinaga, Masafumi; Zhao, Fang-Jie; Rosen, Barry P.

    2015-01-01

    Arsenic is the most prevalent environmental toxic element and causes health problems throughout the world. The toxicity, mobility, and fate of arsenic in the environment are largely determined by its speciation, and arsenic speciation changes are driven, at least to some extent, by biological processes. In this article, biotransformation of arsenic is reviewed from the perspective of the formation of Earth and the evolution of life, and the connection between arsenic geochemistry and biology is described. The article provides a comprehensive overview of molecular mechanisms of arsenic redox and methylation cycles as well as other arsenic biotransformations. It also discusses the implications of arsenic biotransformation in environmental remediation and food safety, with particular emphasis on groundwater arsenic contamination and arsenic accumulation in rice. PMID:26778863

  4. Earth Abides Arsenic Biotransformations

    NASA Astrophysics Data System (ADS)

    Zhu, Yong-Guan; Yoshinaga, Masafumi; Zhao, Fang-Jie; Rosen, Barry P.

    2014-05-01

    Arsenic is the most prevalent environmental toxic element and causes health problems throughout the world. The toxicity, mobility, and fate of arsenic in the environment are largely determined by its speciation, and arsenic speciation changes are driven, at least to some extent, by biological processes. In this article, biotransformation of arsenic is reviewed from the perspective of the formation of Earth and the evolution of life, and the connection between arsenic geochemistry and biology is described. The article provides a comprehensive overview of molecular mechanisms of arsenic redox and methylation cycles as well as other arsenic biotransformations. It also discusses the implications of arsenic biotransformation in environmental remediation and food safety, with particular emphasis on groundwater arsenic contamination and arsenic accumulation in rice.

  5. Applying carbon dioxide, plant growth-promoting rhizobacterium and EDTA can enhance the phytoremediation efficiency of ryegrass in a soil polluted with zinc, arsenic, cadmium and lead.

    PubMed

    Guo, Junkang; Feng, Renwei; Ding, Yongzhen; Wang, Ruigang

    2014-08-01

    This study was conducted to investigate the use of elevated carbon dioxide (CO2), plant growth-promoting rhizobacterium Burkholderia sp. D54 (PGPR) and ethylenediaminetetraacetic acid (EDTA) to enhance the phytoextraction efficiency of ryegrass in response to multiple heavy metal (or metalloid)-polluted soil containing zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb). All of the single or combined CO2, PGPR and EDTA treatments promoted ryegrass growth. The stimulation of ryegrass growth by CO2 and PGPR could primarily be attributed to the regulation of photosynthesis rather than decreased levels of Zn, As and Cd in the shoots. Most treatments seemed to reduce the Zn, As and Cd contents in the shoots, which might be associated with enhanced shoot biomass, thus causing a "dilution effect" regarding their levels. The combined treatments seemed to perform better than single treatments in removing Zn, As, Cd and Pb from soil, judging from the larger biomass and relatively higher total amounts (TAs) of Zn, As, Cd and Pb in both the shoots and roots. Therefore, we suggest that the CO2 plus PGPR treatment will be suitable for removing Zn, As, Cd and Pb from heavy metal (or metalloid)-polluted soils using ryegrass as a phytoremediation material. PMID:24762567

  6. THE CELLUAR METABOLISM OF ARSENIC

    EPA Science Inventory

    Because the methylation of arsenic produces intermediates and terminal products that exceed inorganic arsenic in potency as enzyme inhibitors, cytotoxins, and genotoxins, the methylation of arsenic is properly regarded as an activation process. The methylation of arsenic is an e...

  7. Chem I Supplement: Arsenic and Old Myths.

    ERIC Educational Resources Information Center

    Sarquis, Mickey

    1979-01-01

    Describes the history of arsenic, the properties of arsenic, production and uses of arsenicals, arsenic in the environment; toxic levels of arsenic, arsenic in the human body, and the Marsh Test. (BT)

  8. Transplacental arsenic carcinogenesis in mice

    SciTech Connect

    Waalkes, Michael P. Liu, Jie; Diwan, Bhalchandra A.

    2007-08-01

    Our work has focused on the carcinogenic effects of in utero arsenic exposure in mice. Our data show that a short period of maternal exposure to inorganic arsenic in the drinking water is an effective, multi-tissue carcinogen in the adult offspring. These studies have been reproduced in three temporally separate studies using two different mouse strains. In these studies pregnant mice were treated with drinking water containing sodium arsenite at up to 85 ppm arsenic from days 8 to 18 of gestation, and the offspring were observed for up to 2 years. The doses used in all these studies were well tolerated by both the dam and offspring. In C3H mice, two separate studies show male offspring exposed to arsenic in utero developed liver carcinoma and adrenal cortical adenoma in a dose-related fashion during adulthood. Prenatally exposed female C3H offspring show dose-related increases in ovarian tumors and lung carcinoma and in proliferative lesions (tumors plus preneoplastic hyperplasia) of the uterus and oviduct. In addition, prenatal arsenic plus postnatal exposure to the tumor promoter, 12-O-tetradecanoyl phorbol-13-acetate (TPA) in C3H mice produces excess lung tumors in both sexes and liver tumors in females. Male CD1 mice treated with arsenic in utero develop tumors of the liver and adrenal and renal hyperplasia while females develop tumors of urogenital system, ovary, uterus and adrenal and hyperplasia of the oviduct. Additional postnatal treatment with diethylstilbestrol or tamoxifen after prenatal arsenic in CD1 mice induces urinary bladder transitional cell proliferative lesions, including carcinoma and papilloma, and enhances the carcinogenic response in the liver of both sexes. Overall this model has provided convincing evidence that arsenic is a transplacental carcinogen in mice with the ability to target tissues of potential human relevance, such as the urinary bladder, lung and liver. Transplacental carcinogenesis clearly occurs with other agents in humans

  9. Massive acute arsenic poisonings.

    PubMed

    Lech, Teresa; Trela, Franciszek

    2005-07-16

    Arsenic poisonings are still important in the field of toxicology, though they are not as frequent as about 20-30 years ago. In this paper, the arsenic concentrations in ante- and post-mortem materials, and also forensic and anatomo-pathological aspects in three cases of massive acute poisoning with arsenic(III) oxide (two of them with unexplained criminalistic background, in which arsenic was taken for amphetamine and one suicide), are presented. Ante-mortem blood and urine arsenic concentrations ranged from 2.3 to 6.7 microg/ml, respectively. Post-mortem tissue total arsenic concentrations were also detected in large concentrations. In case 3, the contents of the duodenum contained as much as 30.1% arsenic(III) oxide. The high concentrations of arsenic detected in blood and tissues in all presented cases are particularly noteworthy in that they are very rarely detected at these concentrations in fatal arsenic poisonings. PMID:15939162

  10. Enhanced Photosynthesis and Carbon Metabolism Favor Arsenic Tolerance in Artemisia annua, a Medicinal Plant as Revealed by Homology-Based Proteomics

    PubMed Central

    Pandey, Sarita; Shrivastava, Alok Kumar; Pandey Rai, Shashi

    2014-01-01

    This paper provides the first proteomic evidence of arsenic (As) tolerance and interactive regulatory network between primary and secondary metabolism in the medicinal plant, Artemisia annua. While chlorophyll fluorescence and photosynthetic rate depicted mild inhibition, there was a significant enhancement in PSI activity, whole chain, ATP, and NADPH contents in 100 μM As treatments compared to the control plants. However, a decrease in the above variables was recorded under 150 μM treatments. Proteomic decoding of the survival strategy of A. annua under As stress using 2-DE followed by MALDI-MS/MS revealed a total of 46 differentially expressed protein spots. In contrast to other plants where As inhibits photosynthesis, A. annua showed appreciable photosynthetic CO2 assimilation and allocation of carbon resources at 100 μM As concentration. While an increased accumulation of ATP synthase, ferredoxin-NADP(H) oxidoreductase, and FeS-rieske proteins supported the operation of cyclic electron transport, mdr ABC transporter protein and pcs gene might be involved in As detoxification. The most interesting observation was an increased accumulation of LEAFY like novel protein conceivably responsible for an early onset of flowering in A. annua under As stress. This study not only affirmed the role of energy metabolism proteins but also identified potential candidates responsible for As tolerance in plants. PMID:24868464

  11. Toxic Substances Portal- Arsenic

    MedlinePlus

    ... industrial applications. Organic arsenic compounds are used as pesticides, primarily on cotton fields and orchards. top What ... as copper or lead smelting, wood treating, or pesticide application. top How can arsenic affect my health? ...

  12. Arsenic Trioxide Injection

    MedlinePlus

    Arsenic trioxide is used to treat acute promyelocytic leukemia (APL; a type of cancer in which there ... worsened following treatment with other types of chemotherapy. Arsenic trioxide is in a class of medications called ...

  13. ARSENIC REMOVAL TECHNOLOGY

    EPA Science Inventory

    Presentation will discuss the state-of-art technology for removal of arsenic from drinking water. Presentation includes results of several EPA field studies on removal of arsenic from existing arsenic removal plants and key results from several EPA sponsored research studies. T...

  14. The carcinogenicity of arsenic.

    PubMed Central

    Pershagen, G

    1981-01-01

    A carcinogenic role of inorganic arsenic has been suspected for nearly a century. Exposure to inorganic arsenic compounds occurs in some occupational groups, e.g., among smelter workers and workers engaged in the production and use of arsenic containing pesticides. Substantial exposure can also result from drinking water in certain areas and the use of some drugs. Tobacco and wine have had high As concentrations due to the use of arsenic containing pesticides. Inorganic arsenic compounds interfere with DNA repair mechanisms and an increased frequency of chromosomal aberrations have been observed among exposed workers and patients. Epidemiological data show that inorganic arsenic exposure can cause cancer of the lung and skin. The evidence of an etiologic role of arsenic for angiosarcoma of the liver is highly suggestive; however, the association between arsenic and cancer of other sites needs further investigation. No epidemiological data are available on exposure to organic arsenic compounds and cancer. Animal carcinogenicity studies involving exposure to various inorganic and organic arsenic compounds by different routes have been negative, with the possible exception of some preliminary data regarding lung cancer and leukemia. Some studies have indicated an increased mortality from lung cancer in populations living near point emission sources of arsenic into the air. The role of arsenic cannot be evaluated due to lack of exposure data. Epidemiological data suggest that the present WHO standard for drinking water (50 micrograms As/l.) provides only a small safety margin with regard to skin cancer. PMID:7023936

  15. NEVADA ARSENIC STUDY

    EPA Science Inventory

    The effects of exposure to arsenic in U.S. drinking water at low levels are difficult to assess. In particular, studies of sufficient sample size on US populations exposed to arsenic in drinking water are few. Churchill County, NV (population 25000) has arsenic levels in drinki...

  16. ARSENIC SOURCES AND ASSESSMENT

    EPA Science Inventory

    Recent research has identified a number of potential and current links between environmental arsenic releases and the management of operational and abandoned landfills. Many landfills will receive an increasing arsenic load due to the disposal of arsenic-bearing solid residuals ...

  17. Arsenic in Food

    MedlinePlus

    ... inorganic forms. The FDA has been measuring total arsenic concentrations in foods, including rice and juices, through its Total Diet Study program ... readily take up much arsenic from the ground, rice is different because it takes ... has high levels of less toxic organic arsenic. Do organic foods ...

  18. Identification of QTLs that enhance the nutritional value of rice grain and limit accumulation of undesirable elements such as arsenic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research into the mineral contents of cereal grains and vegetables is motivated by interest in improving their nutritional value. Biofortification refers to natural enhancement of grain/food products through traditional breeding. Since this approach does not require genetic engineering, it is acce...

  19. Arsenic pollution sources.

    PubMed

    Garelick, Hemda; Jones, Huw; Dybowska, Agnieszka; Valsami-Jones, Eugenia

    2008-01-01

    Arsenic is a widely dispersed element in the Earth's crust and exists at an average concentration of approximately 5 mg/kg. There are many possible routes of human exposure to arsenic from both natural and anthropogenic sources. Arsenic occurs as a constituent in more than 200 minerals, although it primarily exists as arsenopyrite and as a constituent in several other sulfide minerals. The introduction of arsenic into drinking water can occur as a result of its natural geological presence in local bedrock. Arsenic-containing bedrock formations of this sort are known in Bangladesh, West Bengal (India), and regions of China, and many cases of endemic contamination by arsenic with serious consequences to human health are known from these areas. Significant natural contamination of surface waters and soil can arise when arsenic-rich geothermal fluids come into contact with surface waters. When humans are implicated in causing or exacerbating arsenic pollution, the cause can almost always be traced to mining or mining-related activities. Arsenic exists in many oxidation states, with arsenic (III) and (V) being the most common forms. Similar to many metalloids, the prevalence of particular species of arsenic depends greatly on the pH and redox conditions of the matrix in which it exists. Speciation is also important in determining the toxicity of arsenic. Arsenic minerals exist in the environment principally as sulfides, oxides, and phosphates. In igneous rocks, only those of volcanic origin are implicated in high aqueous arsenic concentrations. Sedimentary rocks tend not to bear high arsenic loads, and common matrices such as sands and sandstones contain lower concentrations owing to the dominance of quartz and feldspars. Groundwater contamination by arsenic arises from sources of arsenopyrite, base metal sulfides, realgar and orpiment, arsenic-rich pyrite, and iron oxyhydroxide. Mechanisms by which arsenic is released from minerals are varied and are accounted for by

  20. Evaluation of electrokinetic remediation of arsenic-contaminated soils.

    PubMed

    Kim, Soon-Oh; Kim, Won-Seok; Kim, Kyoung-Woong

    2005-09-01

    The potential of electrokinetic (EK) remediation technology has been successfully demonstrated for the remediation of heavy metal-contaminated fine-grained soils through laboratory scale and field application studies. Arsenic contamination in soil is a serious problem affecting both site use and groundwater quality. The EK technology was evaluated for the removal of arsenic from two soil samples; a kaolinite soil artificially contaminated with arsenic and an arsenic-bearing tailing-soil taken from the Myungbong (MB) gold mine area. The effectiveness of enhancing agents was investigated using three different types of cathodic electrolytes; deionized water (DIW), potassium phosphate (KH(2)PO(4)) and sodium hydroxide (NaOH). The results of the experiments on the kaolinite show that the potassium phosphate was the most effective in extracting arsenic, probably due to anion exchange of arsenic species by phosphate. On the other hand, the sodium hydroxide seemed to be the most efficient in removing arsenic from the tailing-soil. This result may be explained by the fact that the sodium hydroxide increased the soil pH and accelerated ionic migration of arsenic species through the desorption of arsenic species as well as the dissolution of arsenic-bearing minerals. PMID:16237600

  1. Arsenic removal from water

    DOEpatents

    Moore, Robert C.; Anderson, D. Richard

    2007-07-24

    Methods for removing arsenic from water by addition of inexpensive and commonly available magnesium oxide, magnesium hydroxide, calcium oxide, or calcium hydroxide to the water. The hydroxide has a strong chemical affinity for arsenic and rapidly adsorbs arsenic, even in the presence of carbonate in the water. Simple and commercially available mechanical methods for removal of magnesium hydroxide particles with adsorbed arsenic from drinking water can be used, including filtration, dissolved air flotation, vortex separation, or centrifugal separation. A method for continuous removal of arsenic from water is provided. Also provided is a method for concentrating arsenic in a water sample to facilitate quantification of arsenic, by means of magnesium or calcium hydroxide adsorption.

  2. Arsenic: homicidal intoxication

    SciTech Connect

    Massey, E.W.; Wold, D.; Heyman, A.

    1984-07-01

    Arsenic-induced deaths have been known to occur from accidental poisoning, as a result of medical therapy, and from intentional poisonings in homicide and suicide. Twenty-eight arsenic deaths in North Carolina from 1972 to 1982 included 14 homicides and seven suicides. In addition, 56 hospitalized victims of arsenic poisoning were identified at Duke Medical Center from 1970 to 1980. Four case histories of arsenic poisoning in North Carolina are presented and clinical manifestations are discussed. In view of the continued widespread use of arsenic in industry and agriculture, and its ubiquity in the environment, arsenic poisoning will continue to occur. A need for knowledge of its toxicity and of the clinical manifestations of acute and chronic arsenic poisoning will also continue.

  3. ARSENIC (+3 OXIDATION STATE) METHYLTRANSFERASE AND THE METHYLATION OF ARSENICALS

    EPA Science Inventory

    Metabolic conversion of inorganic arsenic into methylated products is a multistep process that yields mono, di, and trimethylated arsenicals. In recent years, it has become apparent that formation of methylated metabolites of inorganic arsenic is not necessarily a detoxification...

  4. COMMONALITIES IN METABOLISM OF ARSENICALS

    EPA Science Inventory

    Elucidating the pathway of inorganic arsenic metabolism shows that some of methylated arsenicals formed as intermediates and products are reactive and toxic species. Hence, methylated arsenicals likely mediate at least some of the toxic and carcinogenic effects associated with e...

  5. Combustion characteristics and arsenic retention during co-combustion of agricultural biomass and bituminous coal.

    PubMed

    Zhou, Chuncai; Liu, Guijian; Wang, Xudong; Qi, Cuicui; Hu, Yunhu

    2016-08-01

    A combination of thermogravimetric analysis (TG) and laboratory-scale circulated fluidized bed combustion experiment was conducted to investigate the thermochemical, kinetic and arsenic retention behavior during co-combustion bituminous coal with typical agricultural biomass. Results shown that ignition performance and thermal reactivity of coal could be enhanced by adding biomass in suitable proportion. Arsenic was enriched in fly ash and associated with fine particles during combustion of coal/biomass blends. The emission of arsenic decreased with increasing proportion of biomass in blends. The retention of arsenic may be attributed to the interaction between arsenic and fly ash components. The positive correlation between calcium content and arsenic concentration in ash suggesting that the arsenic-calcium interaction may be regarded as the primary mechanism for arsenic retention. PMID:27136608

  6. Arsenic biomethylation by photosynthetic organisms

    PubMed Central

    Ye, Jun; Rensing, Christopher; Rosen, Barry P.; Zhu, Yong-Guan

    2013-01-01

    Arsenic (As) is a ubiquitous element that is widespread in the environment and causes numerous health problems. Biomethylation of As has implications for its mobility and toxicity. Photosynthetic organisms may play a significant role in As geochemical cycling by methylating it to different As species, but little is known about the mechanisms of methylation. Methylated As species have been found in many photosynthetic organisms, and several arsenite S-adenosylmethionine (SAM) methyltransferases have been characterized in cyanobacteria and algae. However, higher plants may not have the ability to methylate As. Instead, methylated arsenicals in plants probably originate from microorganisms in soils and the rhizosphere. Here, we propose possible approaches for developing ‘smart’ photosynthetic organisms with an enhanced and sensitive biomethylation capacity for bioremediation and safer food. PMID:22257759

  7. Identification of arsenite-and arsenic diglutathione-binding proteins in human hepatocarcinoma cells

    SciTech Connect

    Mizumura, Ayano; Watanabe, Takayuki; Kobayashi, Yayoi; Hirano, Seishiro

    2010-01-15

    It is generally accepted that trivalent arsenicals are more toxic than the corresponding pentavalent arsenicals, since trivalent arsenicals bind the thiol groups of biomolecules, leading to a deterioration in cellular functions. In the present study, we prepared three different arsenic-bound sepharoses and investigated the binding of hepatic cytosolic proteins to pentavalent, trivalent, and glutathione-conjugated trivalent arsenicals. SDS-PAGE showed no proteins bound to pentavalent arsenic specifically. In contrast, we found a number of proteins that have specific and high affinity for trivalent arsenic. Two of those proteins were identified: protein disulfide isomerase-related protein 5 (PDSIRP5) and peroxiredoxin 1/enhancer protein (PRX1/EP). These proteins have vicinal cysteines, as previously reported. In contrast, one of the prominent proteins that did not bind to trivalent arsenic was identified as calreticulin precursor. Although there are 3 cysteines in calreticulin precursor, two of the cysteines are spaced more than 25 amino acids apart. Five synthetic peptides containing 2 vicinal cysteines were prepared to study whether they would inhibit the binding of PDSIRP5, PRX1/EP, and other arsenic-binding proteins to trivalent arsenicals. Only two of the five peptides effectively inhibited binding, suggesting that other amino acids besides the 2 vicinal cysteines may modulate the affinity of cysteine-rich proteins for trivalent arsenicals. We further investigated hepatic cytosolic proteins that bound specifically to glutathione-conjugated trivalent arsenic, which is the most abundant form of arsenical in bile fluid. Four proteins that bound specifically to glutathione-conjugated trivalent arsenic were identified; interestingly, these proteins were different from the trivalent arsenic-binding proteins. These results suggest that although glutathione-conjugation is an important process in the metabolism, excretion, and detoxification of arsenicals, glutathione

  8. Arsenic (+3 oxidation state) methyltransferase and the methylation of arsenicals in the invertebrate chordate Ciona intestinalis

    EPA Science Inventory

    The biotransformation of inorganic arsenic (iAs) involves methylation by an arsenic (+3 oxidation state) methyltransferase (AS3MT), yielding methyl arsenic (MA), dimethyl arsenic (DMA), and trimethylarsenic (TMA). To identify molecular mechanisms that coordinate arsenic biotra...

  9. Arsenic (Environmental Health Student Portal)

    MedlinePlus

    ... Natural Disasters Drinking Water Waterborne Diseases & Illnesses Water Cycle Water Treatment Arsenic The Basics Arsenic is an element that exists naturally in the Earth’s crust. Small amounts of arsenic are found in some rock, soil, water, and air. When arsenic combines with ...

  10. ARSENIC REMOVAL USING ADSORPTION TECHNOLOGIES

    EPA Science Inventory

    The recently promulgated Arsenic Rule will require that many new drinking water systems treat their water to remove arsenic. Many groundwaters that have arsenic in their source water will likely consider adsorption technology as a reasonable approach to remove arsenic. Adsorptio...

  11. ADSORPTION TECHNOLOGIES FOR ARSENIC REMOVAL

    EPA Science Inventory

    The recently promulgated Arsenic Rule will require that many new drinking water systems treat their water to remove arsenic. Many groundwaters that have arsenic in their source water will likely consider adsorption technology as a reasonable approach to remove arsenic. Adsorptio...

  12. ARSENIC AND OHIO UTILITIES

    EPA Science Inventory

    The presentation provides information on arsenic removal drinking water treatment systems that are likely to be used in Ohio for arsenic removal. Because most Ohio ground water contain significant amounts of iron, iron removal processes will play a major role in treating Ohio gro...

  13. Arsenic activation neutron detector

    DOEpatents

    Jacobs, Eddy L.

    1981-01-01

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5 Mev neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  14. Arsenic activation neutron detector

    DOEpatents

    Jacobs, E.L.

    1980-01-28

    A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5-MeV neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

  15. An update on arsenic

    SciTech Connect

    Malachowski, M.E. )

    1990-09-01

    Arsenic poisoning is more than just a medical curiosity. Cases of acute and chronic intoxication continue to occur in the United States. Much is now known about the biochemical mechanisms of injury, which has led to a rational basis for therapy. Most importantly, however, the clinician must stay alert to correctly diagnose and treat cases of arsenic poisoning.23 references.

  16. Arsenic removal from flowing irrigation water in bangladesh: impacts of channel properties.

    PubMed

    Lineberger, Ethan M; Badruzzaman, A Borhan M; Ali, M Ashraf; Polizzotto, Matthew L

    2013-11-01

    Across Bangladesh, dry-season irrigation with arsenic-contaminated well water is loading arsenic onto rice paddies, leading to increased arsenic concentrations in plants, diminished crop yields, and increased human health risks. As irrigation water flows through conveyance channels between wells and rice fields, arsenic concentrations change over space and time, indicating that channels may provide a location for removing arsenic from solution. However, few studies have systematically evaluated the processes controlling arsenic concentrations in irrigation channels, limiting the ability to manipulate these systems and enhance arsenic removal from solution. The central goal of this study was to quantify how channel design affected removal of dissolved arsenic from flowing irrigation water. Field experiments were conducted in Bangladesh using a chemically constant source of arsenic-contaminated irrigation water and an array of constructed channels with varying geometries. The resulting hydraulic conditions affected the quantity of arsenic removed from solution within the channels by promoting known hydrogeochemical processes. Channels three times the width of control channels removed ∼3 times the mass of arsenic over 32 min of flowing conditions, whereas negligible arsenic removal was observed in tarp-lined channels, which prevented soil-water contact. Arsenic removal from solution was ∼7 times higher in a winding, 200-m-long channel than in the straight, 45-m-long control channels. Arsenic concentrations were governed by oxidative iron-arsenic coprecipitation within the water column, sorption to soils, and phosphate competition. Collectively, these results suggest that better design and management of irrigation channels may play a part in arsenic mitigation strategies for rice fields in Southern Asia. PMID:25602413

  17. Acute arsenic intoxication from environmental arsenic exposure

    SciTech Connect

    Franzblau, A.; Lilis, R. )

    1989-11-01

    Reports of acute arsenic poisoning arising from environmental exposure are rare. Two cases of acute arsenic intoxication resulting from ingestion of contaminated well water are described. These patients experienced a variety of problems: acute gastrointestinal symptoms, central and peripheral neurotoxicity, bone marrow suppression, hepatic toxicity, and mild mucous membrane and cutaneous changes. Although located adjacent to an abandoned mine, the well water had been tested for microorganisms only and was found to be safe. Regulations for testing of water from private wells for fitness to drink are frequently nonexistent, or only mandate biologic tests for microorganisms. Well water, particularly in areas near mining activity, should be tested for metals.

  18. Binational Arsenic Exposure Survey: Methodology and Estimated Arsenic Intake from Drinking Water and Urinary Arsenic Concentrations

    PubMed Central

    Roberge, Jason; O’Rourke, Mary Kay; Meza-Montenegro, Maria Mercedes; Gutiérrez-Millán, Luis Enrique; Burgess, Jefferey L.; Harris, Robin B.

    2012-01-01

    The Binational Arsenic Exposure Survey (BAsES) was designed to evaluate probable arsenic exposures in selected areas of southern Arizona and northern Mexico, two regions with known elevated levels of arsenic in groundwater reserves. This paper describes the methodology of BAsES and the relationship between estimated arsenic intake from beverages and arsenic output in urine. Households from eight communities were selected for their varying groundwater arsenic concentrations in Arizona, USA and Sonora, Mexico. Adults responded to questionnaires and provided dietary information. A first morning urine void and water from all household drinking sources were collected. Associations between urinary arsenic concentration (total, organic, inorganic) and estimated level of arsenic consumed from water and other beverages were evaluated through crude associations and by random effects models. Median estimated total arsenic intake from beverages among participants from Arizona communities ranged from 1.7 to 14.1 µg/day compared to 0.6 to 3.4 µg/day among those from Mexico communities. In contrast, median urinary inorganic arsenic concentrations were greatest among participants from Hermosillo, Mexico (6.2 µg/L) whereas a high of 2.0 µg/L was found among participants from Ajo, Arizona. Estimated arsenic intake from drinking water was associated with urinary total arsenic concentration (p < 0.001), urinary inorganic arsenic concentration (p < 0.001), and urinary sum of species (p < 0.001). Urinary arsenic concentrations increased between 7% and 12% for each one percent increase in arsenic consumed from drinking water. Variability in arsenic intake from beverages and urinary arsenic output yielded counter intuitive results. Estimated intake of arsenic from all beverages was greatest among Arizonans yet participants in Mexico had higher urinary total and inorganic arsenic concentrations. Other contributors to urinary arsenic concentrations should be evaluated. PMID:22690182

  19. Environmental biochemistry of arsenic

    SciTech Connect

    Tamaki, S.; Frankenberger, W.T. Jr. )

    1992-01-01

    Microorganisms are involved in the redistribution and global cycling of arsenic. Arsenic can accumulate and can be subject to various biotransformations including reduction, oxidation, and methylation. Bacterial methylation of inorganic arsenic is coupled to the methane biosynthetic pathway in methanogenic bacteria under anaerobic conditions and may be a mechanism for arsenic detoxification. The pathway proceeds by reduction of arsenate to arsenite followed by methylation to dimethylarsine. Fungi are also able to transform inorganic and organic arsenic compounds into volatile methylarsines. The pathway proceeds aerobically by arsenate reduction to arsenite followed by several methylation steps producing trimethylarsine. Volatile arsine gases are very toxic to mammals because they destroy red blood cells (LD50 in rats; 3.0 mg kg-1). Further studies are needed on dimethylarsine and trimethylarsine toxicity tests through inhalation of target animals. Marine algae transform arsenate into non-volatile methylated arsenic compounds (methanearsonic and dimethylarsinic acids) in seawater. This is considered to be a beneficial step not only to the primary producers, but also to the higher trophic levels, since non-volatile methylated arsenic is much less toxic to marine invertebrates. Freshwater algae like marine algae synthesize lipid-soluble arsenic compounds and do not produce volatile methylarsines. Aquatic plants also synthesize similar lipid-soluble arsenic compounds. In terrestrial plants, arsenate is preferentially taken up 3 to 4 times the rate of arsenite. In the presence of phosphate, arsenate uptake is inhibited while in the presence of arsenate, phosphate uptake is only slightly inhibited. There is a competitive interaction between arsenate and phosphate for the same uptake system in terrestrial plants.

  20. Water hyacinth removes arsenic from arsenic-contaminated drinking water.

    PubMed

    Misbahuddin, Mir; Fariduddin, Atm

    2002-01-01

    Water hyacinth (Eichhornia crassipes) removes arsenic from arsenic-contaminated drinking water. This effect depends on several factors, such as the amount of water hyacinth, amount of arsenic present in the water, duration of exposure, and presence of sunlight and air. On the basis of the present study, the authors suggest that water hyacinth is useful for making arsenic-contaminated drinking water totally arsenic free. Water hyacinth provides a natural means of removing arsenic from drinking water at the household level without monetary cost. PMID:12696647

  1. Unraveling the mechanism of neuroprotection of curcumin in arsenic induced cholinergic dysfunctions in rats

    SciTech Connect

    Srivastava, Pranay; Yadav, Rajesh S.; Chandravanshi, Lalit P.; Shukla, Rajendra K.; Dhuriya, Yogesh K.; Chauhan, Lalit K.S.; Dwivedi, Hari N.; Pant, Aditiya B.; Khanna, Vinay K.

    2014-09-15

    Earlier, we found that arsenic induced cholinergic deficits in rat brain could be protected by curcumin. In continuation to this, the present study is focused to unravel the molecular mechanisms associated with the protective efficacy of curcumin in arsenic induced cholinergic deficits. Exposure to arsenic (20 mg/kg body weight, p.o) for 28 days in rats resulted to decrease the expression of CHRM2 receptor gene associated with mitochondrial dysfunctions as evident by decrease in the mitochondrial membrane potential, activity of mitochondrial complexes and enhanced apoptosis both in the frontal cortex and hippocampus in comparison to controls. The ultrastructural images of arsenic exposed rats, assessed by transmission electron microscope, exhibited loss of myelin sheath and distorted cristae in the mitochondria both in the frontal cortex and hippocampus as compared to controls. Simultaneous treatment with arsenic (20 mg/kg body weight, p.o) and curcumin (100 mg/kg body weight, p.o) for 28 days in rats was found to protect arsenic induced changes in the mitochondrial membrane potential and activity of mitochondrial complexes both in frontal cortex and hippocampus. Alterations in the expression of pro- and anti-apoptotic proteins and ultrastructural damage in the frontal cortex and hippocampus following arsenic exposure were also protected in rats simultaneously treated with arsenic and curcumin. The data of the present study reveal that curcumin could protect arsenic induced cholinergic deficits by modulating the expression of pro- and anti-apoptotic proteins in the brain. More interestingly, arsenic induced functional and ultrastructural changes in the brain mitochondria were also protected by curcumin. - Highlights: • Neuroprotective mechanism of curcumin in arsenic induced cholinergic deficits studied • Curcumin protected arsenic induced enhanced expression of stress markers in rat brain • Arsenic compromised mitochondrial electron transport chain protected

  2. [Mixture Leaching Remediation Technology of Arsenic Contaminated Soil].

    PubMed

    Chen, Xun-feng; Li, Xiao-ming; Chen, Can; Yang, Qi; Deng, Lin-jing; Xie, Wei-qiang; Zhong, Yui; Huang, Bin; Yang, Wei-qiang; Zhang, Zhi-bei

    2016-03-15

    Soil contamination of arsenic pollution has become a severely environmental issue, while soil leaching is an efficient method for remediation of arsenic-contaminated soil. In this study, batch tests were primarily conducted to select optimal mixture leaching combination. Firstly, five conventional reagents were selected and combined with each other. Secondly, the fractions were analyzed before and after the tests. Finally, to explore the feasibility of mixed leaching, three soils with different arsenic pollution levels were used to compare the leaching effect. Comparing with one-step washing, the two-step sequential washing with different reagents increased the arsenic removal efficiency. These results showed that the mixture of 4 h 0.5 mol · L⁻¹ NaOH + 4 h 0.1 mol · L⁻¹ EDTA was found to be practicable, which could enhance the removal rate of arsenic from 66.67% to 91.83%, and the concentration of arsenic in soil was decreased from 186 mg · kg⁻¹ to 15.2 mg · kg⁻¹. Furthermore, the results indicated that the distribution of fractions of arsenic in soil changed apparently after mixture leaching. Leaching process could significantly reduce the available contents of arsenic in soil. Moreover, the mixture of 0.5 mol · L⁻¹ NaOH + 0.1 mol L⁻¹ EDTA could well decrease the arsenic concentration in aluminum-type soils, while the mixture of 0.5 mol · L⁻¹ OX + 0.5 mol · L⁻¹ NaOH could well decrease the arsenic concentration in iron-type soils. PMID:27337912

  3. Attenuation of arsenic neurotoxicity by curcumin in rats

    SciTech Connect

    Yadav, Rajesh S.; Sankhwar, Madhu Lata; Shukla, Rajendra K.; Chandra, Ramesh; Pant, Aditya B.; Islam, Fakhrul; Khanna, Vinay K.

    2009-11-01

    In view of continued exposure to arsenic and associated human health risk including neurotoxicity, neuroprotective efficacy of curcumin, a polyphenolic antioxidant, has been investigated in rats. A significant decrease in locomotor activity, grip strength (26%) and rota-rod performance (82%) was observed in rats treated with arsenic (sodium arsenite, 20 mg/kg body weight, p.o., 28 days) as compared to controls. The arsenic treated rats also exhibited a decrease in the binding of striatal dopamine receptors (32%) and tyrosine hydroxylase (TH) immunoreactivity (19%) in striatum. Increased arsenic levels in corpus striatum (6.5 fold), frontal cortex (6.3 fold) and hippocampus (7.0 fold) associated with enhanced oxidative stress in these brain regions, as evident by an increase in lipid perioxidation, protein carbonyl and a decrease in the levels of glutathione and activity of superoxide dismutase, catalase and glutathione peroxidase with differential effects were observed in arsenic treated rats compared to controls. Simultaneous treatment with arsenic (sodium arsenite, 20 mg/kg body weight, p.o., 28 days) and curcumin (100 mg/kg body weight, p.o., 28 days) caused an increase in locomotor activity and grip strength and improved the rota-rod performance in comparison to arsenic treated rats. Binding of striatal dopamine receptors and TH expression increased while arsenic levels and oxidative stress decreased in these brain regions in co-treated rats as compared to those treated with arsenic alone. No significant effect on any of these parameters was observed in rats treated with curcumin (100 mg/kg body weight, p.o., 28 days) alone compared to controls. A significant protection in behavioral, neurochemical and immunohistochemical parameters in rats simultaneously treated with arsenic and curcumin suggest the neuroprotective efficacy of curcumin.

  4. ENZYMOLOGY OF ARSENIC METHYLATION

    EPA Science Inventory

    Enzymology of Arsenic Methylation

    David J. Thomas, Pharmacokinetics Branch, Experimental Toxicology Division, National
    Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park...

  5. USEPA Arsenic Demonstration Program

    EPA Science Inventory

    The presentation provides background information on the USEPA arsenic removal program. The summary includes information on the history of the program, sites and technology selected, and a summary of the data collected from two completed projects.

  6. Complementary arsenic speciation methods: A review

    NASA Astrophysics Data System (ADS)

    Nearing, Michelle M.; Koch, Iris; Reimer, Kenneth J.

    2014-09-01

    The toxicity of arsenic greatly depends on its chemical form and oxidation state (speciation) and therefore accurate determination of arsenic speciation is a crucial step in understanding its chemistry and potential risk. High performance liquid chromatography with inductively coupled mass spectrometry (HPLC-ICP-MS) is the most common analysis used for arsenic speciation but it has two major limitations: it relies on an extraction step (usually from a solid sample) that can be incomplete or alter the arsenic compounds; and it provides no structural information, relying on matching sample peaks to standard peaks. The use of additional analytical methods in a complementary manner introduces the ability to address these disadvantages. The use of X-ray absorption spectroscopy (XAS) with HPLC-ICP-MS can be used to identify compounds not extracted for HPLC-ICP-MS and provide minimal processing steps for solid state analysis that may help preserve labile compounds such as those containing arsenicsbnd sulfur bonds, which can degrade under chromatographic conditions. On the other hand, HPLC-ICP-MS is essential in confirming organoarsenic compounds with similar white line energies seen by using XAS, and identifying trace arsenic compounds that are too low to be detected by XAS. The complementary use of electrospray mass spectrometry (ESI-MS) with HPLC-ICP-MS provides confirmation of arsenic compounds identified during the HPLC-ICP-MS analysis, identification of unknown compounds observed during the HPLC-ICP-MS analysis and further resolves HPLC-ICP-MS by identifying co-eluting compounds. In the complementary use of HPLC-ICP-MS and ESI-MS, HPLC-ICP-MS helps to focus the ESI-MS selection of ions. Numerous studies have shown that the information obtained from HPLC-ICP-MS analysis can be greatly enhanced by complementary approaches.

  7. Airborne arsenic exposure and excretion of methylated arsenic compounds.

    PubMed Central

    Smith, T J; Crecelius, E A; Reading, J C

    1977-01-01

    First void urine samples were collected from copper smelter workers exposed to inorganic arsenic and from unexposed controls. Arsenic compounds (As (III), As (V), methylarsonic acid and dimethylarsinic acid) in these samples were analyzed by selective volatilization as arsines with determination of arsenic by plasma excitation emission spectrometry. On the day preceding the urine sample collection a breathing zone measurement was made of respirable arsenic particulates for each subject. It was found that all of the subjects, including the controls excreted arsenic primarily as methylated species. Approximately 50% of the total arsenic was excreted as dimethylarsinic acid and 20% as methylarsonic acid. Slight differences in the proportion of various arsenic compounds were observed with varying levels of inorganic arsenic exposure. Amounts of arsenic species were all closely correlated with each other and with exposure. Irrespirable particulate exposures were measured on a subset of high exposure workers. Irrespirable arsenic was found to be more closely correlated with excretion of arsenic compounds than was respirable arsenic. PMID:908318

  8. ADSORPTION MEDIA FOR ARSENIC REMOVAL

    EPA Science Inventory

    Presentation will discuss the use of adsorptive media for the removal of arsenic from drinking water. Presentation is a fundamental discussion on the use of adsorptive media for arsenic removal and includes information from several EPA field studies on removal of arsenic from dr...

  9. PROPOSED CARCINOGENIC MECHANISMS FOR ARSENIC

    EPA Science Inventory

    PROPOSED CARCINOGENIC MECHANISMS FOR ARSENIC.

    Arsenic is a human carcinogen in skin, lung, liver, urinary bladder and kidney. In contrast,
    there is no accepted experimental animal model of inorganic arsenic carcinogenesis.
    Proposed mechanisms/modes of action for a...

  10. ARSENIC URINARY METABOLITES: BIOMARKER STUDY

    EPA Science Inventory

    A population of adults and children with ranges of 10 to 300 g/l of arsenic in their drinking water will have their urine analyzed for total and speciated arsenic. A sample of 30 families will be selected based on tap water analyses for arsenic. This sample will comprise 50% adul...

  11. Arsenic exposure at low-to-moderate levels and skin lesions, arsenic metabolism, neurological functions, and biomarkers for respiratory and cardiovascular diseases: Review of recent findings from the Health Effects of Arsenic Longitudinal Study (HEALS) in Bangladesh

    SciTech Connect

    Chen Yu; Parvez, Faruque; Gamble, Mary; Islam, Tariqul; Ahmed, Alauddin; Argos, Maria; Graziano, Joseph H.; Ahsan, Habibul

    2009-09-01

    The contamination of groundwater by arsenic in Bangladesh is a major public health concern affecting 35-75 million people. Although it is evident that high levels (> 300 {mu}g/L) of arsenic exposure from drinking water are related to adverse health outcomes, health effects of arsenic exposure at low-to-moderate levels (10-300 {mu}g/L) are not well understood. We established the Health Effects of Arsenic Longitudinal Study (HEALS) with more than 20,000 men and women in Araihazar, Bangladesh, to prospectively investigate the health effects of arsenic predominately at low-to-moderate levels (0.1 to 864 {mu}g/L, mean 99 {mu}g/L) of arsenic exposure. Findings to date suggest adverse effects of low-to-moderate levels of arsenic exposure on the risk of pre-malignant skin lesions, high blood pressure, neurological dysfunctions, and all-cause and chronic disease mortality. In addition, the data also indicate that the risk of skin lesion due to arsenic exposure is modifiable by nutritional factors, such as folate and selenium status, lifestyle factors, including cigarette smoking and body mass index, and genetic polymorphisms in genes related to arsenic metabolism. The analyses of biomarkers for respiratory and cardiovascular functions support that there may be adverse effects of arsenic on these outcomes and call for confirmation in large studies. A unique strength of the HEALS is the availability of outcome data collected prospectively and data on detailed individual-level arsenic exposure estimated using water, blood and repeated urine samples. Future prospective analyses of clinical endpoints and related host susceptibility will enhance our knowledge on the health effects of low-to-moderate levels of arsenic exposure, elucidate disease mechanisms, and give directions for prevention.

  12. Arsenic (+3 oxidation state) methyltransferase and the methylation of arsenicals in the invertebrate chordate Ciona intestinalis

    EPA Science Inventory

    Biotransformation of inorganic arsenic (iAs) involves methylation catalyzed by arsenic (+3 oxidation state) methyltransferase (As3mt), yielding mono- , di- , and trimethylated arsenicals. To investigate the evolution of molecular mechanisms that mediate arsenic biotransformation,...

  13. Arsenic, Anaerobes, and Astrobiology

    NASA Astrophysics Data System (ADS)

    Stolz, J. F.; Oremland, R. S.; Switzer Blum, J.; Hoeft, S. E.; Baesman, S. M.; Bennett, S.; Miller, L. G.; Kulp, T. R.; Saltikov, C.

    2013-12-01

    Arsenic is an element best known for its highly poisonous nature, so it is not something one would associate with being a well-spring for life. Yet discoveries made over the past two decades have delineated that not only are some microbes resistant to arsenic, but that this element's primary redox states can be exploited to conserve energy and support prokaryotic growth ('arsenotrophy') in the absence of oxygen. Hence, arsenite [As(III)] can serve as an electron donor for chemo- or photo-autotrophy while arsenate [As(V)] will serve as an electron acceptor for chemo-heterotrophs and chemo-autotrophs. The phylogenetic diversity of these microbes is broad, encompassing many individual species from diverse taxonomic groups in the Domain Bacteria, with fewer representatives in the Domain Archaea. Speculation with regard to the evolutionary origins of the key functional genes in anaerobic arsenic transformations (arrA and arxA) and aerobic oxidation (aioB) has led to a disputation as to which gene and function is the most ancient and whether arsenic metabolism extended back into the Archaean. Regardless of its origin, robust arsenic metabolism has been documented in extreme environments that are rich in their arsenic content, such as hot springs and especially hypersaline soda lakes associated with volcanic regions. Searles Lake, CA is an extreme, salt-saturated end member where vigorous arsenic metabolism occurs, but there is no detectable sulfate-reduction or methanogenesis. The latter processes are too weak bio-energetically to survive as compared with arsenotrophy, and are also highly sensitive to the abundance of borate ions present in these locales. These observations have implications with respect to the search for microbial life elsewhere in the Solar System where volcanic-like processes have been operative. Hence, because of the likelihood of encountering dense brines in the regolith of Mars (formed by evapo-concentration) or beneath the ice layers of Europa

  14. Arsenic-mediated nephrotoxicity.

    PubMed

    Robles-Osorio, Ma Ludivina; Sabath-Silva, Elizabeth; Sabath, Ernesto

    2015-05-01

    Chronic kidney disease (CKD) is an important global health problem that affects 8-15% of the population according to epidemiological studies done in different countries. Essential to prevention is the knowledge of the environmental factors associated with this disease, and heavy metals such as lead and cadmium are clearly associated with kidney injury and CKD progression. Arsenic is one of the most abundant contaminants in water and soil, and many epidemiological studies have found an association between arsenic and type 2 diabetes mellitus, hypertension and cancer; however, there is a scarcity of epidemiological studies about its association with kidney disease, and the evidence linking urinary arsenic excretion with CKD, higher urinary excretion of low molecular proteins, albuminuria or other markers of renal in injury is still limited, and more studies are necessary to characterize the role of arsenic on renal injury and CKD progression. Global efforts to reduce arsenic exposure remain important and research is also needed to determine whether specific therapies are beneficial in susceptible populations. PMID:25703706

  15. Arsenic: The Silent Killer

    SciTech Connect

    Foster, Andrea

    2006-02-28

    Andrea Foster uses x-rays to determine the forms of potentially toxic elements in environmentally-important matrices such as water, sediments, plants, and microorganisms. In this free public lecture, Foster will discuss her research on arsenic, which is called the silent killer because dissolved in water, it is colorless, odorless, and tasteless, yet consumption of relatively small doses of this element in its most toxic forms can cause rapid and violent death. Arsenic is a well-known poison, and has been used as such since ancient times. Less well known is the fact that much lower doses of the element, consumed over years, can lead to a variety of skin and internal cancers that can also be fatal. Currently, what has been called the largest mass poisoning in history is occurring in Bangladesh, where most people are by necessity drinking ground water that is contaminated with arsenic far in excess of the maximum amounts determined to be safe by the World Health Organization. This presentation will review the long and complicated history with arsenic, describe how x-rays have helped explain the high yet spatially variable arsenic concentrations in Bangladesh, discuss the ways in which land use in Bangladesh may be exacerbating the problem, and summarize the impact of this silent killer on drinking water systems worldwide.

  16. Influence of groundwater recharge and well characteristics on dissolved arsenic concentrations in southeastern Michigan groundwater

    USGS Publications Warehouse

    Meliker, J.R.; Slotnick, M.J.; Avruskin, G.A.; Haack, S.K.; Nriagu, J.O.

    2009-01-01

    Arsenic concentrations exceeding 10 ??g/l, the United States maximum contaminant level and the World Health Organization guideline value, are frequently reported in groundwater from bedrock and unconsolidated aquifers of southeastern Michigan. Although arsenic-bearing minerals (including arsenian pyrite and oxide/hydroxide phases) have been identified in Marshall Sandstone bedrock of the Mississippian aquifer system and in tills of the unconsolidated aquifer system, mechanisms responsible for arsenic mobilization and subsequent transport in groundwater are equivocal. Recent evidence has begun to suggest that groundwater recharge and characteristics of well construction may affect arsenic mobilization and transport. Therefore, we investigated the relationship between dissolved arsenic concentrations, reported groundwater recharge rates, well construction characteristics, and geology in unconsolidated and bedrock aquifers. Results of multiple linear regression analyses indicate that arsenic contamination is more prevalent in bedrock wells that are cased in proximity to the bedrock-unconsolidated interface; no other factors were associated with arsenic contamination in water drawn from bedrock or unconsolidated aquifers. Conditions appropriate for arsenic mobilization may be found along the bedrock-unconsolidated interface, including changes in reduction/oxidation potential and enhanced biogeochemical activity because of differences between geologic strata. These results are valuable for understanding arsenic mobilization and guiding well construction practices in southeastern Michigan, and may also provide insights for other regions faced with groundwater arsenic contamination. ?? Springer-Verlag 2008.

  17. Plants as Useful Vectors to Reduce Environmental Toxic Arsenic Content

    PubMed Central

    Mirza, Nosheen; Mahmood, Qaisar; Maroof Shah, Mohammad; Pervez, Arshid; Sultan, Sikander

    2014-01-01

    Arsenic (As) toxicity in soil and water is an increasing menace around the globe. Its concentration both in soil and environment is due to natural and anthropogenic activities. Rising arsenic concentrations in groundwater is alarming due to the health risks to plants, animals, and human beings. Anthropogenic As contamination of soil may result from mining, milling, and smelting of copper, lead, zinc sulfide ores, hide tanning waste, dyes, chemical weapons, electroplating, gas exhaust, application of municipal sludge on land, combustion of fossil fuels, As additives to livestock feed, coal fly ash, and use of arsenical pesticides in agricultural sector. Phytoremediation can be viewed as biological, solar-driven, pump-and-treat system with an extensive, self-extending uptake network (the root system) that enhances the natural ecosystems for subsequent productive use. The present review presents recent scientific developments regarding phytoremediation of arsenic contaminated environments and its possible detoxification mechanisms in plants. PMID:24526924

  18. Plants as useful vectors to reduce environmental toxic arsenic content.

    PubMed

    Mirza, Nosheen; Mahmood, Qaisar; Maroof Shah, Mohammad; Pervez, Arshid; Sultan, Sikander

    2014-01-01

    Arsenic (As) toxicity in soil and water is an increasing menace around the globe. Its concentration both in soil and environment is due to natural and anthropogenic activities. Rising arsenic concentrations in groundwater is alarming due to the health risks to plants, animals, and human beings. Anthropogenic As contamination of soil may result from mining, milling, and smelting of copper, lead, zinc sulfide ores, hide tanning waste, dyes, chemical weapons, electroplating, gas exhaust, application of municipal sludge on land, combustion of fossil fuels, As additives to livestock feed, coal fly ash, and use of arsenical pesticides in agricultural sector. Phytoremediation can be viewed as biological, solar-driven, pump-and-treat system with an extensive, self-extending uptake network (the root system) that enhances the natural ecosystems for subsequent productive use. The present review presents recent scientific developments regarding phytoremediation of arsenic contaminated environments and its possible detoxification mechanisms in plants. PMID:24526924

  19. Interstitial injection in silicon after high-dose, low-energy arsenic implantation and annealing

    SciTech Connect

    Tsamis, C.; Skarlatos, D.; BenAssayag, G.; Claverie, A.; Lerch, W.; Valamontes, V.

    2005-11-14

    In this work, we investigate the interstitial injection into the silicon lattice due to high-dose, low-energy arsenic implantation. The approach consists in monitoring the diffusion of the arsenic profile as well as of the boron profile in buried {delta}-doped layers, when amounts of the as-implanted arsenic profile are removed by low-temperature wet silicon etching. The experimental results indicate that the contribution of the implantation damage to the transient enhanced diffusion of boron, and thus the interstitial injection, is not the main one. On the contrary, interstitial generation due to arsenic clustering seems to be more important for the present conditions.

  20. Arsenics as bioenergetic substrates.

    PubMed

    van Lis, Robert; Nitschke, Wolfgang; Duval, Simon; Schoepp-Cothenet, Barbara

    2013-02-01

    Although at low concentrations, arsenic commonly occurs naturally as a local geological constituent. Whereas both arsenate and arsenite are strongly toxic to life, a number of prokaryotes use these compounds as electron acceptors or donors, respectively, for bioenergetic purposes via respiratory arsenate reductase, arsenite oxidase and alternative arsenite oxidase. The recent burst in discovered arsenite oxidizing and arsenate respiring microbes suggests the arsenic bioenergetic metabolisms to be anything but exotic. The first goal of the present review is to bring to light the widespread distribution and diversity of these metabolizing pathways. The second goal is to present an evolutionary analysis of these diverse energetic pathways. Taking into account not only the available data on the arsenic metabolizing enzymes and their phylogenetical relatives but also the palaeogeochemical records, we propose a crucial role of arsenite oxidation via arsenite oxidase in primordial life. This article is part of a Special Issue entitled: The evolutionary aspects of bioenergetic systems. PMID:22982475

  1. Arsenic levels in Oregon waters.

    PubMed Central

    Stoner, J C; Whanger, P D; Weswig, P H

    1977-01-01

    The arsenic content of well water in certain areas of Oregon can range up to 30 to 40 times the U.S.P.H.S. Drinking Water Standard of 1962, where concentrations in excess of 50 ppb are grounds for rejection. The elevated arsenic levels in water are postulated to be due to volcanic deposits. Wells in central Lane County, Oregon, that are known to contain arsenic rich water are in an area underlain by a particular group of sedimentary and volcanic rocks, which geologists have named the Fischer formation. The arsenic levels in water from wells ranged from no detectable amounts to 2,000 ppb. In general the deeper wells contained higher arsenic water. The high arsenic waters are characterized by the small amounts of calcium and magnesium in relation to that of sodium, a high content of boron, and a high pH. Water from some hot springs in other areas of Oregon was found to range as high as 900 ppb arsenic. Arsenic blood levels ranged from 32 ppb for people living in areas where water is low in arsenic to 250 ppb for those living in areas where water is known to contain high levels of arsenic. Some health problems associated with consumption of arsenic-rich water are discussed. PMID:908291

  2. Environmental Source of Arsenic Exposure

    PubMed Central

    Chung, Jin-Yong; Yu, Seung-Do; Hong, Young-Seoub

    2014-01-01

    Arsenic is a ubiquitous, naturally occurring metalloid that may be a significant risk factor for cancer after exposure to contaminated drinking water, cigarettes, foods, industry, occupational environment, and air. Among the various routes of arsenic exposure, drinking water is the largest source of arsenic poisoning worldwide. Arsenic exposure from ingested foods usually comes from food crops grown in arsenic-contaminated soil and/or irrigated with arsenic-contaminated water. According to a recent World Health Organization report, arsenic from contaminated water can be quickly and easily absorbed and depending on its metabolic form, may adversely affect human health. Recently, the US Food and Drug Administration regulations for metals found in cosmetics to protect consumers against contaminations deemed deleterious to health; some cosmetics were found to contain a variety of chemicals including heavy metals, which are sometimes used as preservatives. Moreover, developing countries tend to have a growing number of industrial factories that unfortunately, harm the environment, especially in cities where industrial and vehicle emissions, as well as household activities, cause serious air pollution. Air is also an important source of arsenic exposure in areas with industrial activity. The presence of arsenic in airborne particulate matter is considered a risk for certain diseases. Taken together, various potential pathways of arsenic exposure seem to affect humans adversely, and future efforts to reduce arsenic exposure caused by environmental factors should be made. PMID:25284196

  3. Arsenic Speciation of Terrestrial Invertebrates

    SciTech Connect

    Moriarty, M.M.; Koch, I.; Gordon, R.A.; Reimer, K.J. ); )

    2009-07-01

    The distribution and chemical form (speciation) of arsenic in terrestrial food chains determines both the amount of arsenic available to higher organisms, and the toxicity of this metalloid in affected ecosystems. Invertebrates are part of complex terrestrial food webs. This paper provides arsenic concentrations and arsenic speciation profiles for eight orders of terrestrial invertebrates collected at three historical gold mine sites and one background site in Nova Scotia, Canada. Total arsenic concentrations, determined by inductively coupled plasma mass spectrometry (ICP-MS), were dependent upon the classification of invertebrate. Arsenic species were determined by high-performance liquid chromatography (HPLC) ICP-MS and X-ray absorption spectroscopy (XAS). Invertebrates were found by HPLC ICP-MS to contain predominantly arsenite and arsenate in methanol/water extracts, while XAS revealed that most arsenic is bound to sulfur in vivo. Examination of the spatial distribution of arsenic within an ant tissue highlighted the differences between exogenous and endogenous arsenic, as well as the extent to which arsenic is transformed upon ingestion. Similar arsenic speciation patterns for invertebrate groups were observed across sites. Trace amounts of arsenobetaine and arsenocholine were identified in slugs, ants, and spiders.

  4. ELUCIDATING THE PATHWAY FOR ARSENIC METHYLATION

    EPA Science Inventory

    Enzymatically-catalyzed methylation of arsenic is part of a metabolic pathway that converts inorganic arsenic into methylated products. Hence, in humans chronically exposed to inorganic arsenic, methyl and dimethyl arsenic account for most of the arsenic that is excreted in the ...

  5. ARSENIC SPECIATION ANALYSIS IN HUMAN SALIVA

    EPA Science Inventory

    Background: Determination of arsenic species in human saliva is potentially useful for biomonitoring of human exposure to arsenic and for studying arsenic metabolism. However, there is no report on the speciation analysis of arsenic in saliva. Methods: Arsenic species in saliva ...

  6. Carcinogenic Effects of “Whole-Life” Exposure to Inorganic Arsenic in CD1 Mice

    PubMed Central

    Tokar, Erik J.; Diwan, Bhalchandra A.; Ward, Jerrold M.; Delker, Don A.; Waalkes, Michael P.

    2011-01-01

    In a previously developed mouse model, arsenic exposure in utero induces tumors at multiple sites in the offspring as adults, often duplicating human targets. However, human environmental inorganic arsenic exposure occurs during the entire life span, not just part of gestation. Thus, “whole-life” inorganic arsenic carcinogenesis in mice was studied. CD1 mice were exposed to 0, 6, 12, or 24 ppm arsenic in the drinking water 2 weeks prior to breeding, during pregnancy, lactation, and after weaning through adulthood. Tumors were assessed in offspring until 2 years of age. Arsenic induced dose-related increases in lung adenocarcinoma (both sexes), hepatocellular carcinoma (both sexes), gallbladder tumors (males), and uterine carcinomas. Arsenic induced dose-related increases in ovarian tumors (including carcinomas) starting with the lowest dose. Adrenal tumors increased at all doses (both sexes). Arsenic-induced lung and liver cancers were highly enriched for cancer stem cells, consistent with prior work with skin cancers stimulated by prenatal arsenic. Reproductive tract tumors overexpressed cyclooxygenase-2 and estrogen receptor-α. Arsenic target sites were remarkably similar to prior transplacental studies, although tumors from whole-life exposure were generally more aggressive and frequent. This may indicate that arsenic-induced events in utero dictate target site in some tissues, whereas other exposure periods of arsenic enhance incidence or progression, though other factors could be at play, like cumulative dose. Whole-life arsenic exposure induced tumors at dramatically lower external doses than in utero arsenic only while more realistically duplicating human exposure. PMID:20937726

  7. Matrix modification with silver for the electrothermal atomization of arsenic and selenium

    USGS Publications Warehouse

    Sanzolone, R.F.; Chao, T.T.

    1981-01-01

    Silver as a matrix modifier is shown to improve the carbon-rod atomization of both arsenic and selenium for atomic absorption spectrometry. Compared to nickel, the efficiency of silver is greater for arsenic and about the same for selenium. Silver fulfils two functions in its reaction, namely stabilization during the ashing stage and enhancement of absorbance in the final atomization. ?? 1981.

  8. Arsenic and Selenium

    NASA Astrophysics Data System (ADS)

    Plant, J. A.; Kinniburgh, D. G.; Smedley, P. L.; Fordyce, F. M.; Klinck, B. A.

    2003-12-01

    Arsenic (As) and selenium (Se) have become increasingly important in environmental geochemistry because of their significance to human health. Their concentrations vary markedly in the environment, partly in relation to geology and partly as a result of human activity. Some of the contamination evident today probably dates back to the first settled civilizations which used metals.Arsenic is in group 15 of the periodic table (Table 1) and is usually described as a metalloid. It has only one stable isotope, 75As. It can exist in the -III, -I, 0, III, and V oxidation states (Table 2).

  9. Arsenic removal by coagulation

    SciTech Connect

    Scott, K.N.; Green, J.F.; Do, H.D.; McLean, S.J.

    1995-04-01

    This study evaluated the removal of naturally occurring arsenic in a full-scale (106-mgd) conventional treatment plant. When the source water was treated with 3--10 mg/L of ferric chloride or 6, 10, or 20 mg/L of alum, arsenic removal was 81--96% (ferric chloride) and 23--71% (alum). Metal concentrations in the sludge produced during this study were below the state`s current hazardous waste levels at all coagulant dosages. No operational difficulties were encountered.

  10. Arsenic doped zinc oxide

    SciTech Connect

    Volbers, N.; Lautenschlaeger, S.; Leichtweiss, T.; Laufer, A.; Graubner, S.; Meyer, B. K.; Potzger, K.; Zhou Shengqiang

    2008-06-15

    As-doping of zinc oxide has been approached by ion implantation and chemical vapor deposition. The effect of thermal annealing on the implanted samples has been investigated by using secondary ion mass spectrometry and Rutherford backscattering/channeling geometry. The crystal damage, the distribution of the arsenic, the diffusion of impurities, and the formation of secondary phases is discussed. For the thin films grown by vapor deposition, the composition has been determined with regard to the growth parameters. The bonding state of arsenic was investigated for both series of samples using x-ray photoelectron spectroscopy.

  11. Dynamics of organic and inorganic arsenic in the solution phase of an acidic fen in Germany

    NASA Astrophysics Data System (ADS)

    Huang, J.-H.; Matzner, E.

    2006-04-01

    porewaters were found in the growing season, suggesting an enhancing risk of arsenic transport of ground- and surface-waters under these conditions.

  12. Arsenic transformation and mobilization from minerals by the arsenite oxidizing strain WAO

    USGS Publications Warehouse

    Rhine, E.D.; Onesios, K.M.; Serfes, M.E.; Reinfelder, J.R.; Young, L.Y.

    2008-01-01

    Analysis of arsenic concentrations in New Jersey well water from the Newark Basin showed up to 15% of the wells exceed 10 ??g L-1, with a maximum of 215 ??g L-1. In some geologic settings in the basin, this mobile arsenic could be from the weathering of pyrite (FeS2) found in black shale that contains up to 4% arsenic by weight. We hypothesized that under oxic conditions at circumneutral pH, the microbially mediated oxidation of sulfide in the pyrite lattice would lead to the release of pyrite-bound arsenic. Moreover, the oxidation of aqueous As(III) to As(V) by aerobic microorganisms could further enhance arsenic mobilization from the solid phase. Enrichment cultures under aerobic, As(III)-oxidizing conditions were established under circumneutral pH with weathered black shale from the Newark Basin as the inoculum source. Strain WAO, an autotrophic inorganic-sulfur and As(III)-oxidizer, was isolated and phylogenetically and physiologically characterized. Arsenic mobilization studies from arsenopyrite (FeAsS) mineral, conducted with strain WAO at circumneutral pH, showed microbially enhanced mobilization of arsenic and complete oxidation of released arsenic and sulfur to stoichiometric amounts of arsenate and sulfate. In addition, WAO preferentially colonized pyrite on the surface of arsenic-bearing, black shale thick sections. These findings support the hypothesis that microorganisms can directly mobilize and transform arsenic bound in mineral form at circumneutral pH and suggest that the microbial mobilization of arsenic into groundwater may be important in other arsenic-impacted aquifers. ?? 2008 American Chemical Society.

  13. ARSENIC REMOVAL TREATMENT OPTIONS FOR SINGLE FAMILY HOMES

    EPA Science Inventory

    The presentation provides information on POU and POE arsenic removal drinking water treatment systems. The presentation provides information on the arsenic rule, arsenic chemistry and arsenic treatment. The arsenic treatment options proposed for POU and POE treatment consist prim...

  14. Efficacy of arsenic filtration by Kanchan arsenic filter in Nepal.

    PubMed

    Singh, Anjana; Smith, Linda S; Shrestha, Shreekrishna; Maden, Narendra

    2014-09-01

    Groundwater arsenic contamination has caused a significant public health burden in lowland regions of Nepal. For arsenic mitigation purposes, the Kanchan Arsenic Filter (KAF) was developed and validated for use in 2003 after pilot studies showed its effectiveness in removing arsenic. However, its efficacy in field conditions operating for a long period has been scarcely observed. In this study, we observe the efficacy of KAFs running over 6 months in highly arsenic-affected households in Nawalparasi district. We assessed pair-wise arsenic concentrations of 62 randomly selected household tubewells before filtration and after filtration via KAFs. Of 62 tubewells, 41 had influent arsenic concentration exceeding the Nepal drinking water quality standard value (50 μg/L). Of the 41 tubewells having unsafe arsenic levels, KAFs reduced arsenic concentration to the safe level for only 22 tubewells, an efficacy of 54%. In conclusion, we did not find significantly high efficacy of KAFs in reducing unsafe influent arsenic level to the safe level under the in situ field conditions. PMID:25252363

  15. Sequence of exposure to cadmium and arsenic determines the extent of toxic effects in male Fischer rats.

    PubMed

    Hochadel, J F; Waalkes, M P

    1997-01-15

    Arsenic and cadmium are both priority hazardous substances and human carcinogens. Although there is the potential for simultaneous exposure to both metals, the interactions of cadmium and arsenic are not well defined. We examined the toxicity of these metals when given alone or in alternating sequence to adult male Fischer rats. In the first study, a non-toxic dose of arsenic (22.5 micromol NaAsO2/kg, s.c.) was given 24 h before cadmium (10, 20, or 30 micromol CdCl2/kg, s.c.) and toxicity was assessed 24 h later. Arsenic pretreatment markedly reduced mortality in rats given the high dose of cadmium (9 survivors/10 treated) compared to rats given cadmium alone (2/10). Arsenic pretreatment also reduced cadmium-induced hepatotoxicity, as indicated by serum glutamic oxalacetic transaminase (SGOT) activity, and markedly reduced cadmium-induced testicular hemorrhagic necrosis. Arsenic pretreatment produced an 8-fold increase in hepatic levels of metallothionein (MT), a metal-binding protein often associated with cadmium tolerance. In the second study, a non-toxic dose of cadmium (3 micromol CdCl2/kg, s.c.) was given 24 h before arsenic (68, 79, 84, or 90 micro/mol NaAsO2/kg. s.c.) and toxicity was assessed 24 h later. Cadmium pretreatment did not alter the lethality of the high dose of arsenic and had no effect on arsenic-induced hepatotoxicity. Although cadmium pretreatment had no effect on arsenic toxicity, it produced large increases in hepatic MT (26-fold) before the arsenic challenge and greatly enhanced MT induction after the challenge. Thus, even though both arsenic and cadmium induce MT synthesis, only arsenic pretreatment protects against cadmium intoxication, and cadmium pretreatment does not effect arsenic toxicity. Thus, toxic interactions of arsenic and cadmium appear to depend on the sequence of exposure. PMID:9020510

  16. Enhanced bioreduction of iron and arsenic in sediment by biochar amendment influencing microbial community composition and dissolved organic matter content and composition.

    PubMed

    Chen, Zheng; Wang, Yuanpeng; Xia, Dong; Jiang, Xiuli; Fu, Dun; Shen, Liang; Wang, Haitao; Li, Qing Biao

    2016-07-01

    Biochar derived from the pyrolysis at 500 °C with fresh biogas slurry and residue, was conducted to investigate its potential role in mediating the speciation and mobilization of As(V) and Fe(III) from arsenic-contaminated tailing mine sediment, with consideration of the changes in microbial populations and dissolved organic matter (DOM). The reduction of As(V) (10-13%) and Fe(III) (12-17%) were partly in response to biochar abiotically causing desorption and reduction effect, but were predominantly (87-90% and 83-88% for As(V) and Fe(III)) attributed to biochar stimulating biological reduction. The level of As(III) released from sediment upon biochar amendment (656.35±89.25 μg L(-1)) was significantly higher than the level released without biochar amendment (98.06±19.38 μg L(-1)) after 49 days incubation. Although a low level of Fe(II) (0.81±0.07 mg L(-1)) was determined in the solution when amending with biochar, most of released Fe(II) (166.25±40.25 mg L(-1)) was formed as biochar-Fe(II)minerals composite. More importantly, biochar stimulated the DOM bioavailability in association with bacterial activities mediating As(V) and Fe(III) reduction. High-throughput sequencing results indicated biochar application shifted the soil microbial community and increased the relative abundance of As(V)-/Fe(III)-reducing bacteria, mostly Geobacter, Anaeromyxobacter, Desulfosporosinus and Pedobacter. The discovery of biochar-bacteria-DOM consortium may broaden new understanding into speciation and mobilization of metals, which arouses attention to exploit feasible bioremediation for metal-contaminated sediment. PMID:26954472

  17. ARSENIC TREATMENT OPTIONS

    EPA Science Inventory

    The PPT presentation will provide information on the drinking water treatment options for small utilities to remove arsenic from ground water. The discussion will include information on the EPA BAT listed processes and on some of the newer technologies, such as the iron based ad...

  18. Arsenic Content in American Wine.

    PubMed

    Wilson, Denise

    2015-10-01

    Recent studies that have investigated arsenic content in juice, rice, milk, broth (beef and chicken), and other foods have stimulated an interest in understanding how prevalent arsenic contamination is in the U.S. food and beverage supply. The study described here focused on quantifying arsenic levels in wine. A total of 65 representative wines from the top four wine-producing states in the U.S. were analyzed for arsenic content. All samples contained arsenic levels that exceeded the U.S. Environmental Protection Agency (U.S. EPA) exposure limit for drinking water of 10 parts per billion (ppb) and all samples contained inorganic arsenic. The average arsenic detected among all samples studied was 23.3 ppb. Lead, a common co-contaminant to arsenic, was detected in 58% of samples tested, but only 5% exceeded the U.S. EPA exposure limit for drinking water of 15 ppb. Arsenic levels in American wines exceeded those found in other studies involving water, bottled water, apple juice, apple juice blend, milk, rice syrup, and other beverages. When taken in the context of consumption patterns in the U.S., the pervasive presence of arsenic in wine can pose a potential health risk to regular adult wine drinkers. PMID:26591333

  19. Arsenic in shrimp from Kuwait

    SciTech Connect

    Bou-Olayan, A.H.; Al-Yakoob, S.; Al-Hossaini, M.

    1995-04-01

    Arsenic is ubiquitous in the environment and can accumulate in food via contaminated soil, water or air. It enters the food chain through dry and wet atmospheric deposition. Combustion of oil and coal, use of arsenical fertilizers and pesticides and smelting of ores contributes significantly to the natural background of arsenic in soils and sediments. The metal can be transferred from soil to man through plants. In spite of variation in acute, subacute, and chronic toxic effects to plants and animals, evidence of nutritional essentiality of arsenic for rats, goats, and guinea pigs has been suggested, but has not been confirmed for humans. Adverse toxic effects of arsenic as well as its widespread distribution in the environment raises concern about levels of arsenic in man`s diet. Higher levels of arsenic in the diet can result in a higher accumulation rate. Arsenic levels in marine organisms are influenced by species differences, size of organism, and human activities. Bottom dwellers such as shrimp, crab, and lobster accumulate more arsenic than fish due to their frequent contact with bottom sediments. Shrimp constitute approximately 30% of mean total seafood consumption in Kuwait. This study was designed to determine the accumulation of arsenic in the commercially important jinga shrimp (Metapenaeus affinis) and grooved tiger prawn (Penaeus semisulcatus). 13 refs., 3 figs., 1 tab.

  20. Bengal arsenic, an archive of Himalaya orogeny and paleohydrology.

    PubMed

    Guillot, Stephane; Charlet, Laurent

    2007-10-01

    Holocene groundwater in many districts of the West Bengal and parts of Bangladesh are enriched in arsenic enhancing poisoning effect on humans. One of the main problems to depict the source of arsenic is that this element is very mobile and can be easily removed and recombined from the source during alteration processes, transport and mobilization in sediments. The Ganga-Brahmaputra river system mainly contributed to the buildup of the Bengal fan, which is considered one of the largest modern deltas of the world, then the possible source of the As has probably to be search within the Himalayan belt. We propose that the Indus-Tsangpo suture zone dominated by arc-related rocks and more particularly by large volume of serpentinites enriched in arsenic could be one of the primary source of arsenic. The fact that, the present day arsenic concentration in the main Himalayan river, and particularly the Siang-Brahmaputra river system is not so high as expected can be explained by strong aridic conditions present day prevailing in the Indus-Suture zone and do not favored the weathering of serpentinites into As rich-smectite and Fe-hydroxydes. For the Ganga basin, the original source of arsenic has to be search in the weathering of arc related rocks in the Indus-Tsangpo suture zone followed by its intermediate storage into the sediments of the Siwalik foreland basin, playing the role of arsenic reservoir from Miocene to Pleistocene. Intense tectonic activity in the front of the Himalayan belt associated with high rainfall conditions during the Holocene allowed the arsenic to be remobilized and transported toward the Bay of Bengal. PMID:17952779

  1. The Arsenic crisis in Bangladesh (Invited)

    NASA Astrophysics Data System (ADS)

    Harvey, C.; Ashfaque, K.; Neumann, R. B.; Badruzzaman, B.; Ali, A.

    2010-12-01

    The Ganges Delta suffers from water-borne disease. Arsenic in the groundwater pumped from drinking water wells is causing severe and widespread disease, and these wells were installed, in part, to avoid pathogens in the surface water supply. I will discuss the hydrogeologic controls of arsenic concentrations in groundwater, specifically the role of enhanced groundwater circulation driven by irrigation pumping and the effects of the solute loads transported into aquifers with recharge through different surface features, such as rice fields, rivers, and ponds. I will contrast the approaches taken in Southeast Asia for studying groundwater contamination with methods used in the U.S. I will compare findings from several sites in the region and consider how improved models of the coupled hydrologic and biogeochemical system can be used to provide safer water.

  2. Arsenic poisoning in dairy cattle from naturally occurring arsenic pyrites.

    PubMed

    Hopkirk, R G

    1987-10-01

    An outbreak of arsenic poisoning occurred in which most of a 200 cow dairy herd were affected and six died. The source of the arsenic was naturally occurring arsenic pyrites from the Waiotapu Stream, near Rotorua. Arsenic levels in the nearby soil were as high as 6618 ppm. There was little evidence to suggest that treatment affected the course of the disease. Haematology was of little use in diagnosis, post-mortem signs were not always consistent and persistence of the element in the liver appeared short. Control of further outbreaks have been based on practical measures to minimise the intake of contaminated soil and free laying water by the stock. PMID:16031332

  3. Arsenic Exposure and Toxicology: A Historical Perspective

    PubMed Central

    Hughes, Michael F.; Beck, Barbara D.; Chen, Yu; Lewis, Ari S.; Thomas, David J.

    2011-01-01

    The metalloid arsenic is a natural environmental contaminant to which humans are routinely exposed in food, water, air, and soil. Arsenic has a long history of use as a homicidal agent, but in the past 100 years arsenic, has been used as a pesticide, a chemotherapeutic agent and a constituent of consumer products. In some areas of the world, high levels of arsenic are naturally present in drinking water and are a toxicological concern. There are several structural forms and oxidation states of arsenic because it forms alloys with metals and covalent bonds with hydrogen, oxygen, carbon, and other elements. Environmentally relevant forms of arsenic are inorganic and organic existing in the trivalent or pentavalent state. Metabolism of arsenic, catalyzed by arsenic (+3 oxidation state) methyltransferase, is a sequential process of reduction from pentavalency to trivalency followed by oxidative methylation back to pentavalency. Trivalent arsenic is generally more toxicologically potent than pentavalent arsenic. Acute effects of arsenic range from gastrointestinal distress to death. Depending on the dose, chronic arsenic exposure may affect several major organ systems. A major concern of ingested arsenic is cancer, primarily of skin, bladder, and lung. The mode of action of arsenic for its disease endpoints is currently under study. Two key areas are the interaction of trivalent arsenicals with sulfur in proteins and the ability of arsenic to generate oxidative stress. With advances in technology and the recent development of animal models for arsenic carcinogenicity, understanding of the toxicology of arsenic will continue to improve. PMID:21750349

  4. Dietary Yucca schidigera supplementation reduces arsenic-induced oxidative stress in Swiss albino mice.

    PubMed

    Ince, Sinan; Kucukkurt, Ismail; Turkmen, Ruhi; Demirel, Hasan Huseyin; Sever, Emine

    2013-11-01

    The aim of this study was to clarify the effects of dietary supplementation with Yucca schidigera (Ys) on lipid peroxidation (LPO), antioxidant activity, some biochemical parameters and histopathological changes in arsenic-exposed mice. Forty Swiss albino male mice were divided into five equal groups. Group I (control group) was given normal diet and tap water for 28 days. Group II (arsenic group) was given normal diet and 100 mg/L arsenic along with drinking water for 28 days. Groups III-V were given three different doses of Ys (50, 100 and 200 mg/kg) in supplemented diet and arsenic (100 mg/L) along with drinking water throughout the entire period of 28 days. The arsenic significantly increased serum biochemical parameters and malondialdehyde levels in blood and tissue. However, arsenic significantly decreased tissue glutathione concentration, erythrocyte superoxide dismutase and catalase activities. In contrast, dietary supplementation of Ys, in a dose-dependent manner, resulted in reversal of arsenic-induced oxidative stress, LPO and activities of antioxidant enzymes. Moreover, Ys also exhibited protective action against the arsenic-induced focal gliosis and hyperemi in brain, necrosis and degeneration in liver, degeneration and dilatation in Bowman's capsule of kidney and hyaline degeneration in heart tissue of mice. Consequently, our results demonstrate that Ys especially high-dose supplementation in diet decreases arsenic-induced oxidative stress and enhances the antioxidant defence mechanism and regenerate of tissues in Swiss albino mice. PMID:22609855

  5. Conditioned Flavor Aversion and Brain Fos Expression Following Exposure to Arsenic

    PubMed Central

    García-Medina, Nadia E.; Jiménez-Capdeville, Maria E.; Ciucci, Marc; Martínez, Luz M.; Delgado, Juan M.; Horn, Charles C.

    2007-01-01

    Recent advances in the knowledge of the cellular effects of arsenic have provided insights into the molecular mechanisms of arsenic-associated carcinogenesis, immunotoxicity and cardiovascular disease. In the present experiments we tested the hypothesis that the arrival of arsenic to the gastrointestinal (GI) tract is detected by the gut-brain axis, which includes hindbrain and forebrain nuclei activated by GI stimulation. As a marker of neuronal activation we measured Fos expression using immunohistochemistry. Because Fos expression in these nuclei is closely linked to the development of conditioned flavor aversion (CFA) we also tested the effect of arsenic on CFA. Our experiments indicate that arsenic ingestion is readily detected by the brain, as shown by increased Fos expression after oral administration of arsenic. Furthermore, the vagus nerve, which supplies information from the GI tract to the brain, is not involved in this response because a complete subdiaphragmatic vagotomy did not reduce the effect of arsenic on brain Fos expression, but enhanced this response. In parallel, arsenic ingestion is associated with a robust, dose-dependent CFA, which started at doses as low as 0.1 mg/kg body weight. In summary, these data indicate that arsenic given by oral administration is detected by the brain in low concentrations, and activates specific nuclei, which might trigger behavioral responses, such as CFA. PMID:17420081

  6. DNA repair genotype interacts with arsenic exposure to increase bladder cancer risk

    PubMed Central

    Andrew, Angeline S.; Mason, Rebecca A.; Kelsey, Karl T.; Schned, Alan R.; Marsit, Carmen J.; Nelson, Heather H.; Karagas, Margaret R.

    2009-01-01

    Drinking water arsenic exposure has been associated with increased bladder cancer susceptibility. Epidemiologic and experimental data suggest a co-carcinogenic effect of arsenic with exposure to DNA damaging agents, such as cigarette smoke. Recent evidence further supports the hypothesis that genetic variation in DNA repair genes can modify the arsenic – cancer relationship, possibly because arsenic impairs DNA repair capacity. We tested this hypothesis in a population-based study of bladder cancer with XRCC3, ERCC2 genotype/haplotype and arsenic exposure data on 549 controls and 342 cases. Individual exposure to arsenic was determined in toenail samples by neutron activation. Gene-environment interaction with arsenic exposure was observed in relation to bladder cancer risk for a variant allele of the double-strand break repair gene XRCC3 T241M (adjusted OR 2.8 (1.1–7.3) comparing to homozygous wild type among those in the top arsenic exposure decile (interaction p-value 0.01). Haplotype analysis confirmed the association of the XRCC3 241. Thus, double-strand break repair genotype may enhance arsenic associated bladder cancer susceptibility in the U.S. population. PMID:19429237

  7. Low level arsenic promotes progressive inflammatory angiogenesis and liver blood vessel remodeling in mice

    SciTech Connect

    Straub, Adam C.; Stolz, Donna B.; Vin, Harina; Ross, Mark A.; Soucy, Nicole V.; Klei, Linda R.; Barchowsky, Aaron

    2007-08-01

    The vascular effects of arsenic in drinking water are global health concerns contributing to human disease worldwide. Arsenic targets the endothelial cells lining blood vessels, and endothelial cell activation or dysfunction may underlie the pathogenesis of both arsenic-induced vascular diseases and arsenic-enhanced tumorigenesis. The purpose of the current studies was to demonstrate that exposing mice to drinking water containing environmentally relevant levels of arsenic promoted endothelial cell dysfunction and pathologic vascular remodeling. Increased angiogenesis, neovascularization, and inflammatory cell infiltration were observed in Matrigel plugs implanted in C57BL/6 mice following 5-week exposures to 5-500 ppb arsenic [Soucy, N.V., Mayka, D., Klei, L.R., Nemec, A.A., Bauer, J.A., Barchowsky, A., 2005. Neovascularization and angiogenic gene expression following chronic arsenic exposure in mice. Cardiovasc.Toxicol 5, 29-42]. Therefore, functional in vivo effects of arsenic on endothelial cell function and vessel remodeling in an endogenous vascular bed were investigated in the liver. Liver sinusoidal endothelial cells (LSEC) became progressively defenestrated and underwent capillarization to decrease vessel porosity following exposure to 250 ppb arsenic for 2 weeks. Sinusoidal expression of PECAM-1 and laminin-1 proteins, a hallmark of capillarization, was also increased by 2 weeks of exposure. LSEC caveolin-1 protein and caveolae expression were induced after 2 weeks of exposure indicating a compensatory change. Likewise, CD45/CD68-positive inflammatory cells did not accumulate in the livers until after LSEC porosity was decreased, indicating that inflammation is a consequence and not a cause of the arsenic-induced LSEC phenotype. The data demonstrate that the liver vasculature is an early target of pathogenic arsenic effects and that the mouse liver vasculature is a sensitive model for investigating vascular health effects of arsenic.

  8. Reactive oxygen species mediate arsenic induced cell transformation and tumorigenesis through Wnt/{beta}-catenin pathway in human colorectal adenocarcinoma DLD1 cells

    SciTech Connect

    Zhang Zhuo; Wang Xin; Cheng Senping; Sun Lijuan; Son, Young-Ok; Yao Hua; Li Wenqi; Budhraja, Amit; Li Li; Shelton, Brent J.; Tucker, Thomas; Arnold, Susanne M.; Shi Xianglin

    2011-10-15

    Long term exposure to arsenic can increase incidence of human cancers, such as skin, lung, and colon rectum. The mechanism of arsenic induced carcinogenesis is still unclear. It is generally believed that reactive oxygen species (ROS) may play an important role in this process. In the present study, we investigate the possible linkage between ROS, {beta}-catenin and arsenic induced transformation and tumorigenesis in human colorectal adenocarcinoma cell line, DLD1 cells. Our results show that arsenic was able to activate p47{sup phox} and p67{sup phox}, two key proteins for activation of NADPH oxidase. Arsenic was also able to generate ROS in DLD1 cells. Arsenic increased {beta}-catenin expression level and its promoter activity. ROS played a major role in arsenic-induced {beta}-catenin activation. Treatment of DLD1 cells by arsenic enhanced both transformation and tumorigenesis of these cells. The tumor volumes of arsenic treated group were much larger than those without arsenic treatment. Addition of either superoxide dismutase (SOD) or catalase reduced arsenic induced cell transformation and tumor formation. The results indicate that ROS are involved in arsenic induced cell transformation and tumor formation possible through Wnt/{beta}-catenin pathway in human colorectal adenocarcinoma cell line DLD1 cells. - Highlights: > Arsenic activates NADPH oxidase and increases reactive oxygen species generation in DLD1 cells. > Arsenic increases {beta}-catenin expression. > Inhibition of ROS induced by arsenic reduce {beta}-catenin expression. > Arsenic increases cell transformation in DLD1 cells and tumorigenesis in nude mice. > Blockage of ROS decrease cell transformation and tumorigenesis induced by arsenic.

  9. Identification of An Arsenic Tolerant Double Mutant With a Thiol-Mediated Component And Increased Arsenic Tolerance in PhyA Mutants

    SciTech Connect

    Sung, D.Y.; Lee, D.; Harris, H.; Raab, A.; Feldmann, J.; Meharg, A.; Kumabe, B.; Komives, E.A.; Schroeder, J.I.; /SLAC, SSRL /Sydney U. /Aberdeen U. /UC, San Diego

    2007-04-06

    A genetic screen was performed to isolate mutants showing increased arsenic tolerance using an Arabidopsis thaliana population of activation tagged lines. The most arsenic-resistant mutant shows increased arsenate and arsenite tolerance. Genetic analyses of the mutant indicate that the mutant contains two loci that contribute to arsenic tolerance, designated ars4 and ars5. The ars4ars5 double mutant contains a single T-DNA insertion, ars4, which co-segregates with arsenic tolerance and is inserted in the Phytochrome A (PHYA) gene, strongly reducing the expression of PHYA. When grown under far-red light conditions ars4ars5 shows the same elongated hypocotyl phenotype as the previously described strong phyA-211 allele. Three independent phyA alleles, ars4, phyA-211 and a new T-DNA insertion allele (phyA-t) show increased tolerance to arsenate, although to a lesser degree than the ars4ars5 double mutant. Analyses of the ars5 single mutant show that ars5 exhibits stronger arsenic tolerance than ars4, and that ars5 is not linked to ars4. Arsenic tolerance assays with phyB-9 and phot1/phot2 mutants show that these photoreceptor mutants do not exhibit phyA-like arsenic tolerance. Fluorescence HPLC analyses show that elevated levels of phytochelatins were not detected in ars4, ars5 or ars4ars5, however increases in the thiols cysteine, gamma-glutamylcysteine and glutathione were observed. Compared with wild type, the total thiol levels in ars4, ars5 and ars4ars5 mutants were increased up to 80% with combined buthionine sulfoximine and arsenic treatments, suggesting the enhancement of mechanisms that mediate thiol synthesis in the mutants. The presented findings show that PHYA negatively regulates a pathway conferring arsenic tolerance, and that an enhanced thiol synthesis mechanism contributes to the arsenic tolerance of ars4ars5.

  10. Identification of an arsenic tolerant double mutant with a thiol-mediated component and increased arsenic tolerance in phyA mutants.

    PubMed

    Sung, Dong-Yul; Lee, David; Harris, Hugh; Raab, Andrea; Feldmann, Jörg; Meharg, Andrew; Kumabe, Bryan; Komives, Elizabeth A; Schroeder, Julian I

    2007-03-01

    A genetic screen was performed to isolate mutants showing increased arsenic tolerance using an Arabidopsis thaliana population of activation tagged lines. The most arsenic-resistant mutant shows increased arsenate and arsenite tolerance. Genetic analyses of the mutant indicate that the mutant contains two loci that contribute to arsenic tolerance, designated ars4 and ars5. The ars4ars5 double mutant contains a single T-DNA insertion, ars4, which co-segregates with arsenic tolerance and is inserted in the Phytochrome A (PHYA) gene, strongly reducing the expression of PHYA. When grown under far-red light conditions ars4ars5 shows the same elongated hypocotyl phenotype as the previously described strong phyA-211 allele. Three independent phyA alleles, ars4, phyA-211 and a new T-DNA insertion allele (phyA-t) show increased tolerance to arsenate, although to a lesser degree than the ars4ars5 double mutant. Analyses of the ars5 single mutant show that ars5 exhibits stronger arsenic tolerance than ars4, and that ars5 is not linked to ars4. Arsenic tolerance assays with phyB-9 and phot1/phot2 mutants show that these photoreceptor mutants do not exhibit phyA-like arsenic tolerance. Fluorescence HPLC analyses show that elevated levels of phytochelatins were not detected in ars4, ars5 or ars4ars5, however increases in the thiols cysteine, gamma-glutamylcysteine and glutathione were observed. Compared with wild type, the total thiol levels in ars4, ars5 and ars4ars5 mutants were increased up to 80% with combined buthionine sulfoximine and arsenic treatments, suggesting the enhancement of mechanisms that mediate thiol synthesis in the mutants. The presented findings show that PHYA negatively regulates a pathway conferring arsenic tolerance, and that an enhanced thiol synthesis mechanism contributes to the arsenic tolerance of ars4ars5. PMID:17335514

  11. Arsenic content of homeopathic medicines

    SciTech Connect

    Kerr, H.D.; Saryan, L.A.

    1986-01-01

    In order to test the widely held assumption that homeopathic medicines contain negligible quantities of their major ingredients, six such medicines labeled in Latin as containing arsenic were purchased over the counter and by mail order and their arsenic contents measured. Values determined were similar to those expected from label information in only two of six and were markedly at variance in the remaining four. Arsenic was present in notable quantities in two preparations. Most sales personnel interviewed could not identify arsenic as being an ingredient in these preparations and were therefore incapable of warning the general public of possible dangers from ingestion. No such warnings appeared on the labels.

  12. Detection of trace amount of arsenic in groundwater by laser-induced breakdown spectroscopy and adsorption

    NASA Astrophysics Data System (ADS)

    Haider, A. F. M. Y.; Hedayet Ullah, M.; Khan, Z. H.; Kabir, Firoza; Abedin, K. M.

    2014-03-01

    LIBS technique coupled with adsorption has been applied for the efficient detection of arsenic in liquid. Several adsorbents like tea leaves, bamboo slice, charcoal and zinc oxide have been used to enable sensitive detection of arsenic presence in water using LIBS. Among these, zinc oxide and charcoal show the better results. The detection limits for arsenic in water were 1 ppm and 8 ppm, respectively, when ZnO and charcoal were used as adsorbents of arsenic. To date, the determination of 1 ppm of As in water is the lowest concentration of detected arsenic in water by the LIBS technique. The detection limit of As was lowered to even less than 100 ppb by a combination of LIBS technique, adsorption by ZnO and concentration enhancement technique. Using the combination of these three techniques the ultimate concentration of arsenic was found to be 0.083 ppm (83 ppb) for arsenic polluted water collected from a tube-well of Farajikandi union (longitude 90.64°, latitude 23.338° north) of Matlab Upozila of Chandpur district in Bangladesh. This result compares fairly well with the finding of arsenic concentration of 0.078 ppm in the sample by the AAS technique at the Bangladesh Council of Scientific and Industrial Research (BCSIR) lab. Such a low detection limit (1 ppm) of trace elements in liquid matrix has significantly enhanced the scope of LIBS as an analytical tool.

  13. Homicidal arsenic poisoning.

    PubMed

    Duncan, Andrew; Taylor, Andrew; Leese, Elizabeth; Allen, Sam; Morton, Jackie; McAdam, Julie

    2015-07-01

    The case of a 50-year-old man who died mysteriously after being admitted to hospital is reported. He had raised the possibility of being poisoned prior to his death. A Coroner's post-mortem did not reveal the cause of death but this was subsequently established by post-mortem trace element analysis of liver, urine, blood and hair all of which revealed very high arsenic concentrations. PMID:25344454

  14. INFLUENCE OF DIETARY ARSENIC ON URINARY ARSENIC METABOLITE EXCRETION

    EPA Science Inventory

    Influence of Dietary Arsenic on Urinary Arsenic Metabolite Excretion

    Cara L. Carty, M.S., Edward E. Hudgens, B.Sc., Rebecca L. Calderon, Ph.D., M.S.P.H., Richard Kwok, M.S.P.H., Epidemiology and Biomarkers Branch/HSD, NHEERL/US EPA; David J. Thomas, Ph.D., Pharmacokinetics...

  15. Genetic and field management strategies to enhance the nutritional value of rice grains and limit accumulation of undesirable elements such as arsenic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enhancing the nutritional value of rice grains is of particular interest because rice is a primary dietary component for more than half of the world’s population, and is a primary source of nutrients in many underdeveloped countries. Because rice can be grown under both flooded and unflooded field ...

  16. Arsenic hazards to humans, plants, and animals from gold mining

    USGS Publications Warehouse

    Eisler, R.

    2004-01-01

    Arsenic sources to the biosphere associated with gold mining include waste soil and rocks, residual water from ore concentrations, roasting of some types of gold-containing ores to remove sulfur and sulfur oxides, and bacterially-enhanced leaching. Arsenic concentrations near gold mining operations were elevated in abiotic materials and biota: maximum total arsenic concentrations measured were 560 ug/L in surface waters, 5.16 mg/L in sediment pore waters, 5.6 mg/kg dry weight (DW) in bird liver, 27 mg/kg DW in terrestrial grasses, 50 mg/kg DW in soils, 79 mg/kg DW in aquatic plants, 103 mg/kg DW in bird diets, 225 mg/kg DW in soft parts of bivalve molluscs, 324 mg/L in mine drainage waters, 625 mg/kg DW in aquatic insects, 7700 mg/kg DW in sediments, and 21,000 mg/kg DW in tailings. Single oral doses of arsenicals that were fatal to 50% of tested species ranged from 17 to 48 mg/kg body weight (BW) in birds and from 2.5 to 33 mg/kg BW in mammals. Susceptible species of mammals were adversely affected at chronic doses of 1 to 10 mg As/kg BW, or 50 mg As/kg diet. Sensitive aquatic species were damaged at water concentrations of 19 to 48 ug As/L, 120 mg As/kg diet, or tissue residues (in the case of freshwater fish) >1.3 mg/kg fresh weight. Adverse effects to crops and vegetation were recorded at 3 to 28 mg of water-soluble As/L (equivalent to about 25 to 85 mg total As/kg soil) and at atmospheric concentrations >3.9 ug As/m3. Gold miners had a number of arsenic-associated health problems including excess mortality from cancer of the lung, stomach, and respiratory tract. Miners and schoolchildren in the vicinity of gold mining activities had elevated urine arsenic of 25.7 ug/L (range 2.2-106.0 ug/L). Of the total population at this location, 20% showed elevated urine arsenic concentrations associated with future adverse health effects; arsenic-contaminated drinking water is the probable causative factor of elevated arsenic in urine. Proposed arsenic criteria to protect

  17. OPTIMIZING ARSENIC REMOVAL DURING IRON REMOVAL PROCESSES

    EPA Science Inventory

    The recently promulgated Arsenic rule will require that many new drinking water systems treat their water to remove arsenic. Many groundwaters that have arsenic in their source water also have iron in their water. As a result, arsenic treatment at these sites will most likely b...

  18. KINETIC AND DYNAMIC ASPECTS OF ARSENIC TOXICITY

    EPA Science Inventory

    This project integrates research on aspects of the kinetic and dynamic behavior of arsenic. A PBPK model for arsenic will be developed using metabolism and disposition data from studies in mice. Retention of arsenic in the tissues following exposure to arsenic will be investigate...

  19. Arsenic Is A Genotoxic Carcinogen

    EPA Science Inventory

    Arsenic is a recognized human carcinogen; however, there is controversy over whether or not it should be considered a genotoxic carcinogen. Many possible modes of action have been proposed on how arsenic induces cancer, including inhibiting DNA repair, altering methylation patter...

  20. ARSENIC - SUSCEPTIBILITY & IN UTERO EFFECTS

    EPA Science Inventory

    Exposure to inorganic arsenic remains a serious public health problem at many locations worldwide. If has often been noted that prevalences of signs and symptoms of chronic arsenic poisoning differ among various populations. For example, skin lesions or peripheral vascular dis...

  1. MECHANISMS OF ARSENICAL INDUCED MALFORMATIONS

    EPA Science Inventory

    Our research uses the whole embryo culture system to expose mouse embryos to arsenic at the neurulation stage of development (This stage of development is most susceptible to arsenical-induced defects). This includes studies to assess the distribution of cells in the cell cycle a...

  2. ARSENIC TECHNICAL WORKSHOP PROCEEDINGS DOCUMENT

    EPA Science Inventory

    Arsenic is a semi-metallic element or metalloid which has several different allotropic forms. Arsenic compounds, mainly as As2O3, can be recovered as a by-product from processing complex ores mined for other minerals such as copper, lead, zinc, gold and silver. Consequently, ...

  3. Arsenic Removal from Drinking Water

    EPA Science Inventory

    Web cast presentation covered six topics: 1), Arsenic Chemistry, 2), Technology Selection/Arsenic Demonstration Program, 3), Case Study 1, 4), Case Study 2,5), Case Study 3, and 6), Media Regeneration Project. The presentation consists of material presented at other training sess...

  4. Organic matter-solid phase interactions are critical for predicting arsenic release and plant uptake in Bangladesh paddy soils.

    PubMed

    Williams, Paul N; Zhang, Hao; Davison, William; Meharg, Andrew A; Hossain, Mahmud; Norton, Gareth J; Brammer, Hugh; Islam, M Rafiqul

    2011-07-15

    Agroecological zones within Bangladesh with low levels of arsenic in groundwater and soils produce rice that is high in arsenic with respect to other producing regions of the globe. Little is known about arsenic cycling in these soils and the labile fractions relevant for plant uptake when flooded. Soil porewater dynamics of field soils (n = 39) were recreated under standardized laboratory conditions to investigate the mobility and interplay of arsenic, Fe, Si, C, and other elements, in relation to rice grain element composition, using the dynamic sampling technique diffusive gradients in thin films (DGT). Based on a simple model using only labile DGT measured arsenic and dissolved organic carbon (DOC), concentrations of arsenic in Aman (Monsoon season) rice grain were predicted reliably. DOC was the strongest determinant of arsenic solid-solution phase partitioning, while arsenic release to the soil porewater was shown to be decoupled from that of Fe. This study demonstrates the dual importance of organic matter (OM), in terms of enhancing arsenic release from soils, while reducing bioavailability by sequestering arsenic in solution. PMID:21692537

  5. Phytoremediation of arsenic contaminated soil by Pteris vittata L. I. Influence of phosphatic fertilizers and repeated harvests.

    PubMed

    Mandal, Asit; Purakayastha, T J; Patra, A K; Sanyal, S K

    2012-12-01

    A greenhouse experiment was conducted to evaluate the effectiveness of diammonium phosphate (DAP), single superphosphate (SSP) and two growing cycles on arsenic removal by Chinese Brake Fern (Pteris vittata L.) from an arsenic contaminated Typic Haplustept of the Indian state of West Bengal. After harvest of Pteris vittata the total, Olsen's extractable and other five soil arsenic fractions were determined. The total biomass yield of P. vittata ranged from 10.7 to 16.2 g pot(-1) in first growing cycle and from 7.53 to 11.57 g pot(-1) in second growing cycle. The frond arsenic concentrations ranged from 990 to 1374 mg kg(-1) in first growing cycle and from 875 to 1371 mg kg(-1) in second growing cycle. DAP was most efficient in enhancing biomass yield, frond and root arsenic concentrations and total arsenic removal from soil. After first growing cycle, P. vittata reduced soil arsenic by 10 to 20%, while after two growing cycles Pteris reduced it by 18 to 34%. Among the different arsenic fractions, Fe-bound arsenic dominated over other fractions. Two successive harvests with DAP as the phosphate fertilizer emerged as the promising management strategy for amelioration of arsenic contaminated soil of West Bengal through phyotoextraction by P. vittata. PMID:22908659

  6. Electroadsorption-assisted direct determination of trace arsenic without interference using transmission X-ray fluorescence spectroscopy.

    PubMed

    Jiang, Tian-Jia; Guo, Zheng; Liu, Jin-Huai; Huang, Xing-Jiu

    2015-08-18

    An analytical technique based on electroadsorption and transmission X-ray fluorescence (XRF) for the quantitative determination of arsenic in aqueous solution with ppb-level limits of detection (LOD) is proposed. The approach uses electroadsorption to enhance the sensitivity and LOD of the arsenic XRF response. Amine-functionalized carbonaceous microspheres (NH2-CMSs) are found to be the ideal materials for both the quantitative adsorption of arsenic and XRF analysis due to the basic amine sites on the surface and their noninterference in the XRF spectrum. In electroadsorptive X-ray fluorescence (EA-XRF), arsenic is preconcentrated by a conventional three-electrode system with a positive electricity field around the adsorbents. Then, the quantification of arsenic on the adsorbents is achieved using XRF. The electroadsorption preconcentration can realize the fast transfer of arsenic from the solution to the adsorbents and improve the LOD of conventional XRF compared with directly determining arsenic solution by XRF alone. The sensitivity of 0.09 cnt ppb(-1) is obtained without the interferences from coexisted metal ions in the determination of arsenic, and the LOD is found to be 7 ppb, which is lower than the arsenic guideline value of 10 ppb given by the World Health Organization (WHO). These results demonstrated that XRF coupled with electroadsorption was able to determine trace arsenic in real water sample. PMID:26211572

  7. Readily available phosphorous and nitrogen counteract for arsenic uptake and distribution in wheat (Triticum aestivum L.)

    PubMed Central

    Brackhage, Carsten; Huang, Jen-How; Schaller, Jörg; Elzinga, Evert J.; Dudel, E. Gert

    2014-01-01

    Elevated arsenic content in food crops pose a serious human health risk. Apart from rice wheat being another main food crop is possibly cultivated on contaminated sites. But for wheat uptake mechanisms are not entirely understood especially with regard to nutrient fertilization and different moisture regimes taking into account heavy rainfall events due to climate change. Here we show that especially higher P-fertilization under changing redox conditions may enhance arsenic uptake. This counteracts with higher N-fertilization reducing arsenic transfer and translocation into aboveground plant parts for both higher P-fertilization and reducing soil conditions. Arsenic speciation did not change in grain but for leaves P-fertilization together with reducing conditions increased the As(V) content compared to other arsenic species. Our results indicate important dependencies of nutrient fertilization, moisture conditions and substrate type on As accumulation of wheat as one of the most important crop plants worldwide with implications for agricultural practices. PMID:24821134

  8. Readily available phosphorous and nitrogen counteract for arsenic uptake and distribution in wheat (Triticum aestivum L.)

    NASA Astrophysics Data System (ADS)

    Brackhage, Carsten; Huang, Jen-How; Schaller, Jörg; Elzinga, Evert J.; Dudel, E. Gert

    2014-05-01

    Elevated arsenic content in food crops pose a serious human health risk. Apart from rice wheat being another main food crop is possibly cultivated on contaminated sites. But for wheat uptake mechanisms are not entirely understood especially with regard to nutrient fertilization and different moisture regimes taking into account heavy rainfall events due to climate change. Here we show that especially higher P-fertilization under changing redox conditions may enhance arsenic uptake. This counteracts with higher N-fertilization reducing arsenic transfer and translocation into aboveground plant parts for both higher P-fertilization and reducing soil conditions. Arsenic speciation did not change in grain but for leaves P-fertilization together with reducing conditions increased the As(V) content compared to other arsenic species. Our results indicate important dependencies of nutrient fertilization, moisture conditions and substrate type on As accumulation of wheat as one of the most important crop plants worldwide with implications for agricultural practices.

  9. Sulfide-driven arsenic mobilization from arsenopyrite and black shale pyrite

    USGS Publications Warehouse

    Zhu, W.; Young, L.Y.; Yee, N.; Serfes, M.; Rhine, E.D.; Reinfelder, J.R.

    2008-01-01

    We examined the hypothesis that sulfide drives arsenic mobilization from pyritic black shale by a sulfide-arsenide exchange and oxidation reaction in which sulfide replaces arsenic in arsenopyrite forming pyrite, and arsenide (As-1) is concurrently oxidized to soluble arsenite (As+3). This hypothesis was tested in a series of sulfide-arsenide exchange experiments with arsenopyrite (FeAsS), homogenized black shale from the Newark Basin (Lockatong formation), and pyrite isolated from Newark Basin black shale incubated under oxic (21% O2), hypoxic (2% O2, 98% N2), and anoxic (5% H2, 95% N2) conditions. The oxidation state of arsenic in Newark Basin black shale pyrite was determined using X-ray absorption-near edge structure spectroscopy (XANES). Incubation results show that sulfide (1 mM initial concentration) increases arsenic mobilization to the dissolved phase from all three solids under oxic and hypoxic, but not anoxic conditions. Indeed under oxic and hypoxic conditions, the presence of sulfide resulted in the mobilization in 48 h of 13-16 times more arsenic from arsenopyrite and 6-11 times more arsenic from isolated black shale pyrite than in sulfide-free controls. XANES results show that arsenic in Newark Basin black shale pyrite has the same oxidation state as that in FeAsS (-1) and thus extend the sulfide-arsenide exchange mechanism of arsenic mobilization to sedimentary rock, black shale pyrite. Biologically active incubations of whole black shale and its resident microorganisms under sulfate reducing conditions resulted in sevenfold higher mobilization of soluble arsenic than sterile controls. Taken together, our results indicate that sulfide-driven arsenic mobilization would be most important under conditions of redox disequilibrium, such as when sulfate-reducing bacteria release sulfide into oxic groundwater, and that microbial sulfide production is expected to enhance arsenic mobilization in sedimentary rock aquifers with major pyrite-bearing, black

  10. Confounding variables in the environmental toxicology of arsenic.

    PubMed

    Gebel, T

    2000-04-01

    Arsenic is one of the most important global environmental toxicants. For example, in regions of West Bengal and Inner Mongolia, more than 100000 persons are chronically exposed to well water often strongly contaminated with As. Unfortunately, a toxicologically safe risk assessment and standard setting, especially for long-term and low-dose exposures to arsenic, is not possible. One reason is that the key mechanism of arsenic's tumorigenicity still is not elucidated. Experimental data indicate that either DNA repair inhibition or DNA methylation status alteration may be causal explanations. Moreover, when comparing epidemiological data, it cannot be ruled out that the susceptibility to arsenic's carcinogenicity may be different between Mexican and Taiwanese people. Some other studies indicate that some Andean populations do not develop skin cancer after long-term exposure to As. It is not known yet how this resistance could be mediated. Finally, the situation is even more complicated when taking into consideration that there are several compounds suspected to modulate the chronic environmental toxicity of arsenic, variables that may either enhance or suppress the in vivo genotoxicity and carcinogenicity of the metalloid. Among them are nutritional factors like selenium and zinc as well as drinking water co-contaminants like antimony. Further, yet unidentified factors influencing the body burden and/or the excretion of arsenic are possibly prevailing: preliminary data from own human biomonitoring studies showed a peaking of As in urine samples of non-exposed people which was not caused by elevated exposure to As through seafood consumption. The relevance of these putative confounding variables cannot be finally evaluated yet. Further experimental as well as epidemiological studies are needed to answer these questions. This would help to conduct a toxicologically improved risk assessment, especially for low-dose and long-term exposures to arsenic. PMID:10781883

  11. Arsenic concentrations in Chinese coals.

    PubMed

    Wang, Mingshi; Zheng, Baoshan; Wang, Binbin; Li, Shehong; Wu, Daishe; Hu, Jun

    2006-03-15

    The arsenic concentrations in 297 coal samples were collected from the main coal-mines of 26 provinces in China were determined by molybdenum blue coloration method. These samples were collected from coals that vary widely in coal rank and coal-forming periods from the five main coal-bearing regions in China. Arsenic content in Chinese coals range between 0.24 to 71 mg/kg. The mean of the concentration of Arsenic is 6.4+/-0.5 mg/kg and the geometric mean is 4.0+/-8.5 mg/kg. The level of arsenic in China is higher in northeastern and southern provinces, but lower in northwestern provinces. The relationship between arsenic content and coal-forming period, coal rank is studied. It was observed that the arsenic contents decreases with coal rank in the order: Tertiary>Early Jurassic>Late Triassic>Late Jurassic>Middle Jurassic>Late Permian>Early Carboniferous>Middle Carboniferous>Late Carboniferous>Early Permian; It was also noted that the arsenic contents decrease in the order: Subbituminous>Anthracite>Bituminous. However, compared with the geological characteristics of coal forming region, coal rank and coal-forming period have little effect on the concentration of arsenic in Chinese coal. The average arsenic concentration of Chinese coal is lower than that of the whole world. The health problems in China derived from in coal (arsenism) are due largely to poor local life-style practices in cooking and home heating with coal rather than to high arsenic contents in the coal. PMID:16256172

  12. *Arsenic (+3 oxidation state) methyltransferase and the methylation of arsenicals in the invertebrate chordate ciona intestinalis

    EPA Science Inventory

    Biotransformation of inorganic arsenic (iAs) involves methylation catalyzed by arsenic (+3 oxidation state) methyltransferase (As3mt) , yielding mono-, di-, and trimethylated arsenicals. A comparative genomic approach focused on Ciona intestinaJis, an invertebrate chordate, was u...

  13. THE ROLE OF PROTEIN BINDING OF TRIVALENT ARSENICALS IN ARSENIC CARCINOGENESIS AND TOXICITY

    EPA Science Inventory

    Three of the most plausible biological theories of arsenic carcinogenesis are protein binding, oxidative stress and altered DNA methylation. This review presents the role of trivalent arsenicals binding to proteins in arsenic carcinogenesis. Using vacuum filtration based receptor...

  14. Production of selenium-72 and arsenic-72

    DOEpatents

    Phillips, Dennis R.

    1995-01-01

    Methods and apparatus for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72. The invention provides apparatus which can be located at a site where arsenic-72 is used, for purposes such as PET imaging, to produce arsenic-72 as needed, since the half-life of arsenic-72 is very short.

  15. Production of selenium-72 and arsenic-72

    DOEpatents

    Phillips, Dennis R.

    1994-01-01

    Methods and apparatus for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72. The invention provides apparatus which can be located at a site where arsenic-72 is used, for purposes such as PET imaging, to produce arsenic-72 as needed, since the half-life of arsenic-72 is very short.

  16. Production of selenium-72 and arsenic-72

    DOEpatents

    Phillips, D.R.

    1994-12-06

    Methods and apparatus are described for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72. The invention provides apparatus which can be located at a site where arsenic-72 is used, for purposes such as PET imaging, to produce arsenic-72 as needed, since the half-life of arsenic-72 is very short. 2 figures.

  17. Diapause as escape strategy to exposure to toxicants: response of Brachionus calyciforus to arsenic.

    PubMed

    Aránguiz-Acuña, Adriana; Serra, Manuel

    2016-05-01

    Invertebrate organisms commonly respond to environmental fluctuation by entering diapause. Production of diapause in monogonont rotifers involves a previous switch from asexual to partial sexual reproduction. Although zooplankton have been used in ecotoxicological assays, often their true vulnerability to toxicants is underestimated by not incorporating the sexual phase. We experimentally analyzed traits involved in sexual reproduction and diapause in the cyclically parthenogenetic freshwater rotifer, Brachionus calyciflorus, exposed to arsenic, a metalloid naturally found in high concentrations in desert zones, focusing on the effectiveness of diapause as an escape response in the face of an adverse condition. Addition of sublethal concentrations of arsenic modified the pattern of diapause observed in the rotifer: investment in diapause with arsenic addition peaked earlier and higher than in non-toxicant conditions, which suggests that sexual investment could be enhanced in highly stressed environmental conditions by increased responsiveness to stimulation. Nevertheless, eggs produced in large amount with arsenic, were mostly low quality, and healthy-looking eggs had lower hatching success, therefore it is unclear whether this pattern is optimum in an environment with arsenic, or if rather arsenic presence in water bodies disturbs the optimal allocation of offspring entering diapause. We observed high accumulation of arsenic in organisms exposed to constant concentration after several generations, which suggests that arsenic may be accumulated transgenerationally. The sexual phase in rotifers may be more sensitive to environmental conditions than the asexual one, therefore diapause attributes should be considered in ecotoxicological assessment because of its ecological and evolutionary implications on lakes biodiversity. PMID:26897746

  18. Mechanism of erythrocyte death in human population exposed to arsenic through drinking water

    SciTech Connect

    Biswas, Debabrata; Banerjee, Mayukh; Sen, Gargi; Das, Jayanta K.; Banerjee, Apurba; Sau, T.J.; Pandit, Sudipta; Giri, A.K. Biswas, Tuli

    2008-07-01

    Arsenic contamination in drinking water is one of the biggest natural calamities, which has become an imperative threat to human health throughout the world. Abbreviation of erythrocyte lifespan leading to the development of anemia is a common sequel in arsenic exposed population. This study was undertaken to explore the mechanism of cell death in human erythrocytes during chronic arsenic exposure. Results revealed transformation of smooth discoid red cells into evaginated echinocytic form in the exposed individuals. Further distortion converted reversible echinocytes to irreversible spheroechinocytes. Arsenic toxicity increased membrane microviscosity along with an elevation of cholesterol/phospholipid ratio, which hampered the flexibility of red cell membrane and made them less deformable. Significant increase in the binding of merocyanine 540 with erythrocyte membrane due to arsenic exposure indicated disruption of lipid packing in the outer leaflet of the cell membrane resulting from altered transbilayer phospholipid asymmetry. Arsenic induced eryptosis was characterized by cell shrinkage and exposure of phosphatidylserine at the cell surface. Furthermore, metabolic starvation with depletion of cellular ATP triggered apoptotic removal of erythrocytes from circulation. Significant decrease in reduced glutathione content indicating defective antioxidant capacity was coupled with enhancement of malondialdehyde and protein carbonyl levels, which pointed to oxidative damage to erythrocyte membrane. Arsenic toxicity intervened into red cell membrane integrity eventually leading to membrane destabilization and hemoglobin release. The study depicted the involvement of both erythrophagocytosis and hemolysis in the destruction of human erythrocytes during chronic arsenic exposure.

  19. Invertebrates control metals and arsenic sequestration as ecosystem engineers.

    PubMed

    Schaller, Jörg; Weiske, Arndt; Mkandawire, Martin; Dudel, E Gert

    2010-03-01

    Organic sediments are known to be a significant sink of inorganic elements in polluted freshwater ecosystems. Hence, we investigated the role of invertebrate shredders (the freshwater shrimp Gammarus pulex L.) in metal and arsenic enrichment into organic partitions of sediments in a wetland stream at former uranium mining site. Metal and metalloid content in leaf litter increased significantly during decomposition, while at the same time the carbon content decreased. During decomposition, G. pulex as a ecosystem engineer facilitated significantly the enrichment of magnesium (250%), manganese (560%), cobalt (310%), copper (200%), zinc (43%), arsenic (670%), cadmium (100%) and lead (1340%) into small particle sizes. The enrichments occur under very high concentrations of dissolved organic carbon. Small particles have high surface area that results in high biofilm development. Further, the highest amounts of elements were observed in biofilms. Therefore, invertebrate shredder like G. pulex can enhance retention of large amounts of metal and arsenic in wetlands. PMID:20132960

  20. Adsorption and desorption characteristics of arsenic onto ceria nanoparticles

    NASA Astrophysics Data System (ADS)

    Feng, Qinzhong; Zhang, Zhiyong; Ma, Yuhui; He, Xiao; Zhao, Yuliang; Chai, Zhifang

    2012-01-01

    The rapid increase in the use of engineered nanoparticles [ENPs] has resulted in an increasing concern over the potential impacts of ENPs on the environmental and human health. ENPs tend to adsorb a large variety of toxic chemicals when they are emitted into the environment, which may enhance the toxicity of ENPs and/or adsorbed chemicals. The study was aimed to investigate the adsorption and desorption behaviors of arsenic on ceria NPs in aqueous solution using batch technique. Results show that the adsorption behavior of arsenic on ceria NPs was strongly dependent on pH and independent of ionic strength, indicating that the electrostatic effect on the adsorption of these elements was relatively not important compared to surface chemical reactions. The adsorption isotherms fitted very well to both the Langmuir and Freundlich models. The thermodynamic parameters (Δ H 0 , Δ S 0 , and Δ G 0 ) for the adsorption of arsenic were determined at three different temperatures of 283, 303, and 323 K. The adsorption reaction was endothermic, and the process of adsorption was favored at high temperature. The desorption data showed that desorption hysteresis occurred at the initial concentration studied. High adsorption capacity of arsenic on ceria NPs suggests that the synergistic effects of ceria NPs and arsenic on the environmental systems may exist when they are released into the environment.

  1. Electro-removal of arsenic(III) and arsenic(V) from aqueous solutions by capacitive deionization.

    PubMed

    Fan, Chen-Shiuan; Tseng, Ssu-Chia; Li, Kung-Cheh; Hou, Chia-Hung

    2016-07-15

    The feasibility of the electro-removal of arsenate (As(V)) and arsenite (As(III)) from aqueous solutions via capacitive deionization was investigated. The effects of applied voltage (0.0-1.2V) and initial concentration (0.1-200mgL(-1)) on arsenic removal were examined. As evidenced, an enhancement of arsenic removal can be achieved by capacitive deionization. The capacity to remove As(V) at an initial concentration of 0.2mgL(-1) on the activated carbon electrode at 1.2V was determined to be 2.47×10(-2)mgg(-1), which is 1.8-fold higher than that of As(III) (1.37×10(-2)mgg(-1)). Notably, the possible transformation of arsenic species was further characterized. The higher effectiveness of As(V) removal via electrosorption at 1.2V was attributed to the formation of an electrical double layer at the electrode/solution interface. The removal of As(III) could be achieved by the oxidation of As(III) to As(V) and subsequent electrosorption of the As(V) onto the electrode surface of the anode. The presence of sodium chloride or natural organic matter was found to considerably decrease arsenic removal. Single-pass electrosorption-desorption experiments conducted at 1.2V further demonstrated that capacitive deionization is a potential means of effectively removing arsenic from aqueous solutions. PMID:27037475

  2. Mouse arsenic (+3 oxidation state) methyltransferase genotype affects metabolism and tissue dosimetry of arsenicals after arsenite administration in drinking water

    EPA Science Inventory

    Arsenic (+3 oxidation state) methyltransferase (As3mt) catalyzes methylation of inorganic arsenic producing a number of methylated arsenic metabolites. Although methylation has been commonly considered a pathway for detoxification of arsenic, some highly reactive methylated ars...

  3. Arsenic behavior in newly drilled wells

    USGS Publications Warehouse

    Kim, M.-J.; Nriagu, J.; Haack, S.

    2003-01-01

    In the present paper, inorganic arsenic species and chemical parameters in groundwater were determined to investigate the factors related to the distribution of arsenic species and their dissolution from rock into groundwater. For the study, groundwater and core samples were taken at different depths of two newly drilled wells in Huron and Lapeer Counties, Michigan. Results show that total arsenic concentrations in the core samples varied, ranging from 0.8 to 70.7 mg/kg. Iron concentration in rock was about 1800 times higher than that of arsenic, and there was no correlation between arsenic and iron occurrences in the rock samples. Arsenic concentrations in groundwater ranged from <1 to 171 ??g/l. The arsenic concentration in groundwater depended on the amount of arsenic in aquifer rocks, and as well decreased with increasing depth. Over 90% of arsenic existed in the form of As(III), implying that the groundwater systems were in the reduced condition. The results such as high ferrous ion, low redox potential and low dissolved oxygen supported the observed arsenic species distribution. There was no noticeable difference in the total arsenic concentration and arsenic species ratio between unfiltered and filtered (0.45 ??m) waters, indicating that the particulate form of arsenic was negligible in the groundwater samples. There were correlations between water sampling depth and chemical parameters, and between arsenic concentration and chemical parameters, however, the trends were not always consistent in both wells. ?? 2003 Elsevier Science Ltd. All rights reserved.

  4. Magnetic moment formation due to arsenic vacancies in LaFeAsO-derived superconductors

    PubMed Central

    Kikoin, Konstantin; Drechsler, Stefan-Ludwig; Koepernik, Klaus; Málek, Jiři; van den Brink, Jeroen

    2015-01-01

    Arsenic vacancies in LaFeAsO-derived superconductors are nominally non-magnetic defects. However, we find from a microscopic theory in terms of an appropriately modified Anderson-Wolff model that in their vicinity local magnetic moments form. They can arise because removing an arsenic atom breaks four strong, covalent bonds with the neighboring iron atoms. The moments emerging around an arsenic vacancy orient ferromagnetically and cause a substantial enhancement of the paramagnetic susceptibility in both the normal and superconducting state. The qualitative model description is supported by first principles band structure calculations of the As-vacancy related defect spectrum within a larger supercell. PMID:26169486

  5. Association of oxidative stress with arsenic methylation in chronic arsenic-exposed children and adults

    SciTech Connect

    Xu Yuanyuan; Wang Yi; Zheng Quanmei; Li Xin; Li Bing; Jin Yaping; Sun Xiance; Sun Guifan

    2008-10-01

    Though oxidative stress is recognized as an important pathogenic mechanism of arsenic, and arsenic methylation capacity is suggested to be highly involved in arsenic-related diseases, the association of arsenic methylation capacity with arsenic-induced oxidative stress remains unclear. To explore oxidative stress and its association with arsenic methylation, cross-sectional studies were conducted among 208 high and 59 low arsenic-exposed subjects. Levels of urinary arsenic species [inorganic arsenic (iAs), monomethylated arsenic (MMA) and dimethylated arsenic (DMA)] were determined by hydride generation atomic absorption spectrometry. Proportions of urinary arsenic species, the first methylation ratio (FMR) and the secondary methylation ratio (SMR) were used as indicators for arsenic methylation capacity. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations were analyzed by enzyme-linked immunosorbent assay kits. Reduced glutathione (GSH) levels and superoxide dismutase (SOD) activity in whole blood were determined to reflect anti-oxidative status. The high arsenic-exposed children and adults were significantly increased in urinary 8-OHdG concentrations but decreased in blood GSH levels compared with the low exposed children and adults. In multiple linear regression models, blood GSH levels and urinary 8-OHdG concentrations of arsenic-exposed children and adults showed strong associations with the levels of urinary arsenic species. Arsenic-exposed subjects in the lower and the upper quartiles of proportions of urinary arsenic species, FMR or SMR were significantly different in urinary 8-OHdG, blood GSH and SOD. The associations of arsenic methylation capacity with 8-OHdG, GSH and SOD were also observed in multivariate regression analyses. These results may provide linkage between arsenic methylation capacity and oxidative stress in humans and suggest that adverse health effects induced by arsenic are related to arsenic methylation through oxidative stress.

  6. Adverse health effects due to arsenic exposure: Modification by dietary supplementation of jaggery in mice

    SciTech Connect

    Singh, Nrashant; Kumar, D.; Lal, Kewal; Raisuddin, S.; Sahu, Anand P.

    2010-02-01

    Populations of villages of eastern India and Bangladesh and many other parts of the world are exposed to arsenic mainly through drinking water. Due to non-availability of safe drinking water they are compelled to depend on arsenic-contaminated water. Generally, poverty level is high in those areas and situation is compounded by the lack of proper nutrition. The hypothesis that the deleterious health effects of arsenic can be prevented by modification of dietary factors with the availability of an affordable and indigenous functional food jaggery (sugarcane juice) has been tested in the present study. Jaggery contains polyphenols, vitamin C, carotene and other biologically active components. Arsenic as sodium-m-arsenite at low (0.05 ppm) and high (5 ppm) doses was orally administered to Swiss male albino mice, alone and in combination with jaggery feeding (250 mg/mice), consecutively for 180 days. The serum levels of total antioxidant, glutathione peroxidase and glutathione reductase were substantially reduced in arsenic-exposed groups, while supplementation of jaggery enhanced their levels in combined treatment groups. The serum levels of interleukin-1beta, interleukin-6 and TNF-alpha were significantly increased in arsenic-exposed groups, while in the arsenic-exposed and jaggery supplemented groups their levels were normal. The comet assay in bone marrow cells showed the genotoxic effects of arsenic, whereas combination with jaggery feeding lessened the DNA damage. Histopathologically, the lung of arsenic-exposed mice showed the necrosis and degenerative changes in bronchiolar epithelium with emphysema and thickening of alveolar septa which was effectively antagonized by jaggery feeding. These results demonstrate that jaggery, a natural functional food, effectively antagonizes many of the adverse effects of arsenic.

  7. Effects of low arsenic concentration exposure on freshwater fish in the presence of fluvial biofilms.

    PubMed

    Tuulaikhuu, Baigal-Amar; Bonet, Berta; Guasch, Helena

    2016-02-15

    Arsenic (As) is a highly toxic element and its carcinogenic effect on living organisms is well known. However, predicting real effects in the environment requires an ecological approach since toxicity is influenced by many environmental and biological factors. The purpose of this paper was to evaluate if environmentally-realistic arsenic exposure causes toxicity to fish. An experiment with four different treatments (control (C), biofilm (B), arsenic (+As) and biofilm with arsenic (B+As)) was conducted and each one included sediment to enhance environmental realism, allowing the testing of the interactive effects of biofilm and arsenic on the toxicity to fish. Average arsenic exposure to Eastern mosquitofish (Gambusia holbrooki) was 40.5 ± 7.5 μg/L for +As treatment and 34.4 ± 1.4 μg/L for B+As treatment for 56 days. Fish were affected directly and indirectly by this low arsenic concentration since exposure did not only affect fish but also the function of periphytic biofilms. Arsenic effects on the superoxide dismutase (SOD) and glutathione reductase (GR) activities in the liver of mosquitofish were ameliorated in the presence of biofilms at the beginning of exposure (day 9). Moreover, fish weight gaining was only affected in the treatment without biofilm. After longer exposure (56 days), effects of exposure were clearly seen. Fish showed a marked increase in the catalase (CAT) activity in the liver but the interactive influence of biofilms was not further observed since the arsenic-affected biofilm had lost its role in water purification. Our results highlight the interest and application of incorporating some of the complexity of natural systems in ecotoxicology and support the use of criterion continuous concentration (CCC) for arsenic lower than 150 μg/L and closer to the water quality criteria to protect aquatic life recommended by the Canadian government which is 5 μg As/L. PMID:26657392

  8. Geochemical processes controlling fate and transport of arsenic in acid mine drainage (AMD) and natural systems.

    PubMed

    Cheng, Hefa; Hu, Yuanan; Luo, Jian; Xu, Bin; Zhao, Jianfu

    2009-06-15

    Acid mine drainage (AMD) is often accompanied with elevated concentrations of arsenic, in the forms of arsenite, As(III), and/or arsenate, As(V), due to the high affinity of arsenic for sulfide mineral ores. This review summarizes the major geochemical processes controlling the release, speciation, fate, and distribution of inorganic arsenic in mine drainage and natural systems. Arsenic speciation depends highly on redox potential and pH of the solution, and arsenite can be oxidized to the less toxic arsenate form. Homogeneous oxidation of arsenite occurs rather slowly while its heterogeneous oxidation on mineral surfaces can greatly enhance the reaction rates. Little evidence suggests that precipitation reaction limits the concentrations of arsenic in natural water, while co-precipitation may lead to rapid arsenic removal when large amount of iron hydroxides precipitate out of the aqueous phase upon neutralization of the mine drainage. Both arsenate and arsenite adsorb on common metal oxides and clay minerals through formation of inner-sphere and/or outer-sphere complexes, controlling arsenic concentration in natural water bodies. Arsenite adsorbs less strongly than arsenate in the typical pH range of natural water and is more mobile. Part of the adsorbed arsenic species can be exchanged by common anions (e.g., PO(4)(3-) and SO(4)(2-)), especially phosphate, which leads to their re-mobilization. Understanding the geochemistry of arsenic is helpful for predicting its mobility and fate in AMD and natural systems, and for designing of cost-effective remediation/treatment strategies to reduce the occurrence and risk of arsenic contamination. PMID:19070955

  9. The role of thiol species in the hypertolerance of Aspergillus sp. P37 to arsenic.

    PubMed

    Cánovas, David; Vooijs, Riet; Schat, Henk; de Lorenzo, Víctor

    2004-12-01

    Aspergillus sp. P37 is an arsenate-hypertolerant fungus isolated from a river in Spain with a long history of contamination with metals. This strain is able to grow in the presence of 0.2 M arsenate, i.e. 20-fold higher than the reference strain, Aspergillus nidulans TS1. Although Aspergillus sp. P37 reduces As(V) to As(III), which is slowly pumped out of the cell, the measured efflux of oxyanions is insufficient to explain the high tolerance levels of this strain. To gain an insight into this paradox, the accumulation of acid-soluble thiol species in Aspergillus sp. P37 when exposed to arsenic was compared with that of the arsenic-sensitive A. nidulans TS1 strain. Increasing levels of arsenic in the medium did not diminish the intracellular pool of reduced glutathione in Aspergillus sp. P37, in sharp contrast with the decline of glutathione in A. nidulans under the same conditions. Furthermore, concentrations of arsenic that were inhibitory for the sensitive A. nidulans strain (e.g. 50 mM and above) provoked a massive formation of vacuoles filled with thiol species. Because the major fraction of the cellular arsenic was present as the glutathione conjugate As(GS)3, it is plausible that the arsenic-hypertolerant phenotype of Aspergillus sp. P37 is in part due to an enhanced capacity to maintain a large intracellular glutathione pool under conditions of arsenic exposure and to sequester As(GS)3 in vacuoles. High pressure liquid chromatography analysis of cell extracts revealed that the contact of Aspergillus sp. P37 (but not A. nidulans) with high arsenic concentrations (> or =150 mM) induced the production of small quantities of a distinct thiol species indistinguishable from plant phytochelatin-2. Yet, we argue that phytochelatins do not explain arsenic resistance in Aspergillus, and we advocate the role of As(GS)3 complexes in arsenic detoxification. PMID:15364940

  10. THE PATHWAY OF ARSENIC METABLISM

    EPA Science Inventory

    The Pathway of Arsenic Methylation

    David J. Thomas, Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC

    Understanding ...

  11. ARSENIC TREATMENT BY ADSORPTIVE TECHNOLOGY

    EPA Science Inventory

    Presentation will discuss the removal of arsenic from drinking water using the adsorptive media treatment process. Fundamental information is provided on the design and operation of adsorptive media technology including the selection of the adsorptive media. The information cites...

  12. [Arsenic as an environmental problem].

    PubMed

    Jensen, K

    2000-12-01

    Chronic exposure to arsenic through drinking water is known in different continents. Arsenic compounds from disintegrating rock may be solubilized after reduction by organic material, and harmful concentrations of arsenic may be found in surface water as well as in water from drilled wells. Because of well drilling since the sixties in the Ganges delta numerous millions of people have been exposed to toxic amounts, and hundreds of thousands demonstrate signs of chronic poisoning. A changed water technology and chemical precipitation of arsenic in the drinking water can reduce the size of the problem, but the late sequelae i.e. malignant disease are incalculable. Indications for antidotal treatment of exposed individuals have not yet been outlined. PMID:11188053

  13. Impact of carbon nanotubes on the toxicity of inorganic arsenic [AS(III) and AS(V)] to Daphnia magna: The role of certain arsenic species.

    PubMed

    Wang, Xinghao; Qu, Ruijuan; Allam, Ahmed A; Ajarem, Jamaan; Wei, Zhongbo; Wang, Zuoyao

    2016-07-01

    As a type of emerging nanomaterial, hydroxylated multiwalled carbon nanotubes (OH-MWCNTs) may interact with other pollutants in the aquatic environments and further influence their toxicity, transport, and fate. Thus, evaluation of toxicity to arsenic in the presence of CNTs needs to receive much more attention. The present study was conducted to explore the underlying mechanisms of OH-MWCNT-induced arsenic (As[III] and As[V]) toxicity changes in the aquatic organism Daphnia magna at different pH levels. The most toxic species for As(III) and As(V) to D. magna were found to be H2 AsO3 (-) and H2 AsO4 (-) . It appeared that the pH values were of greatest importance when the biological toxicity of As(III) and As(V) was compared. Furthermore, the effects of OH-MWCNTs on arsenic toxicity to D. magna indicated that the presence of OH-MWCNTs could enhance the toxicity of arsenic. The interactions of arsenic with OH-MWCNTs were further investigated by conducting adsorption experiments. The adsorption capacity of As(V) by OH-MWCNTs was found to be higher than that of As(III). To conclude, adsorption of certain arsenic species onto OH-MWCNTs is crucial for a reliable interpretation of enhanced toxicity. Environ Toxicol Chem 2016;35:1852-1859. © 2016 SETAC. PMID:26681408

  14. Arsenic-induced cutaneous hyperplastic lesions are associated with the dysregulation of Yap, a Hippo signaling-related protein

    SciTech Connect

    Li, Changzhao; Srivastava, Ritesh K.; Elmets, Craig A.; Afaq, Farrukh; Athar, Mohammad

    2013-09-06

    Highlights: •Arsenic activates canonical Hippo signaling pathway and up-regulates αCatenin in the skin. •Arsenic activates transcriptional activity of Yap by its nuclear translocation. •Yap is involved in the disruption of tight/adherens junctions in arsenic-exposed animals. -- Abstract: Arsenic exposure in humans causes a number of toxic manifestations in the skin including cutaneous neoplasm. However, the mechanism of these alterations remains elusive. Here, we provide novel observations that arsenic induced Hippo signaling pathway in the murine skin. This pathway plays crucial roles in determining organ size during the embryonic development and if aberrantly activated in adults, contributes to the pathogenesis of epithelial neoplasm. Arsenic treatment enhanced phosphorylation-dependent activation of LATS1 kinase and other Hippo signaling regulatory proteins Sav1 and MOB1. Phospho-LATS kinase is known to catalyze the inactivation of a transcriptional co-activator, Yap. However, in arsenic-treated epidermis, we did not observed its inactivation. Thus, as expected, unphosphorylated-Yap was translocated to the nucleus in arsenic-treated epidermis. Yap by binding to the transcription factors TEADs induces transcription of its target genes. Consistently, an up-regulation of Yap-dependent target genes Cyr61, Gli2, Ankrd1 and Ctgf was observed in the skin of arsenic-treated mice. Phosphorylated Yap is important in regulating tight and adherens junctions through its binding to αCatenin. We found disruption of these junctions in the arsenic-treated mouse skin despite an increase in αCatenin. These data provide evidence that arsenic-induced canonical Hippo signaling pathway and Yap-mediated disruption of tight and adherens junctions are independently regulated. These effects together may contribute to the carcinogenic effects of arsenic in the skin.

  15. Arsenic removal by ferric chloride

    SciTech Connect

    Hering, J.G.; Chen, P.Y.; Wilkie, J.A.; Elimelech, M.; Liang, S.

    1996-04-01

    Bench-scale studies were conducted in model freshwater systems to investigate how various parameters affected arsenic removal during coagulation with ferric chloride and arsenic adsorption onto preformed hydrous ferric oxide. Parameters included arsenic oxidation state and initial concentration, coagulant dosage or adsorbent concentration, pH, and the presence of co-occurring inorganic solutes. Comparison of coagulation and adsorption experiments and of experimental results with predictions based on surface complexation modeling demonstrated that adsorption is an important (though not the sole) mechanism governing arsenic removal during coagulation. Under comparable conditions, better removal was observed with arsenic(V) [As(V)] than with arsenic(III) [As(III)] in both coagulation and adsorption experiments. Below neutral pH values, As(III) removal-adsorption was significantly decreased in the presence of sulfate, whereas only a slight decrease in As(V) removal-adsorption was observed. At high pH, removal-adsorption of As(V) was increased in the presence of calcium. Removal of As(V) during coagulation with ferric chloride is both more efficient and less sensitive than that of As(III) to variations in source water composition.

  16. Life and death with arsenic

    PubMed Central

    Rosen, Barry P.; Ajees, A. Abdul; McDermott, Timothy R.

    2013-01-01

    Arsenic and phosphorus are group 15 elements with similar chemical properties. Is it possible that arsenate could replace phosphate in some of the chemicals that are required for life? Phosphate esters are ubiquitous in biomolecules and are essential for life, from the sugar phosphates of intermediary metabolism to ATP to phospholipids to the phosphate backbone of DNA and RNA. Some enzymes that form phosphate esters catalyze the formation of arsenate esters. Arsenate esters hydrolyze very rapidly in aqueous solution, which makes it improbable that phosphorous could be completely replaced with arsenic to support life. Studies of bacterial growth at high arsenic:phosphorus ratios demonstrate that relatively high arsenic concentrations can be tolerated, and that arsenic can become involved in vital functions in the cell, though likely much less efficiently than phosphorus. Recently Wolfe-Simon et al. [1] reported the isolation of a microorganism that they maintain uses arsenic in place of phosphorus for growth. Here, we examine and evaluate their data and conclusions. PMID:21387349

  17. Arsenic and dichlorvos: Possible interaction between two environmental contaminants.

    PubMed

    Flora, Swaran J S

    2016-05-01

    Metals are ubiquitously present in the environment and pesticides are widely used throughout the world. Environmental and occupational exposure to metal along with pesticide is an area of great concern to both the public and regulatory authorities. Our major concern is that combination of these toxicant present in environment may elicit toxicity either due to additive or synergistic interactions or 'joint toxic actions' among these toxicants. It poses a rising threat to human health. Water contamination particularly ground water contamination with arsenic is a serious problem in today's scenario since arsenic is associated with several kinds of health problems, such arsenic associated health anomalies are commonly called as 'Arsenism'. Uncontrolled use and spillage of pesticides into the environment has resulted in alarming situation. Moreover serious concerns are being addressed due to their persistence in the environmental matrices such as air, soil and surface water runoff resulting in continuous exposure of these harmful chemicals to human beings and animals. Bio-availability of these environmental toxicants has been enhanced much due to anthropological activities. Dreadfully very few studies are available on combined exposures to these toxicants on the animal or human system. Studies on the acute and chronic exposure to arsenic and DDVP are well reported and well defined. Arsenic is a common global ground water contaminant while dichlorvos is one of the most commonly and widely employed organophosphate based insecticide used in agriculture, horticulture etc. There is thus a real situation where a human may get exposed to these toxicants while working in a field. This review highlights the individual and combined exposure to arsenic and dichlorvos on health. PMID:27049126

  18. Arsenic Toxicity in Male Reproduction and Development

    PubMed Central

    Kim, Yoon-Jae; Kim, Jong-Min

    2015-01-01

    Arsenic is a toxic metalloid that exists ubiquitously in the environment, and affects global health problems due to its carcinogenicity. In most populations, the main source of arsenic exposure is the drinking water. In drinking water, chronic exposure to arsenic is associated with increased risks of various cancers including those of skin, lung, bladder, and liver, as well as numerous other non-cancer diseases including gastrointestinal and cardiovascular diseases, diabetes, and neurologic and cognitive problems. Recent emerging evidences suggest that arsenic exposure affects the reproductive and developmental toxicity. Prenatal exposure to inorganic arsenic causes adverse pregnancy outcomes and children’s health problems. Some epidemiological studies have reported that arsenic exposure induces premature delivery, spontaneous abortion, and stillbirth. In animal studies, inorganic arsenic also causes fetal malformation, growth retardation, and fetal death. These toxic effects depend on dose, route and gestation periods of arsenic exposure. In males, inorganic arsenic causes reproductive dysfunctions including reductions of the testis weights, accessory sex organs weights, and epididymal sperm counts. In addition, inorganic arsenic exposure also induces alterations of spermatogenesis, reductions of testosterone and gonadotrophins, and disruptions of steroidogenesis. However, the reproductive and developmental problems following arsenic exposure are poorly understood, and the molecular mechanism of arsenic-induced reproductive toxicity remains unclear. Thus, we further investigated several possible mechanisms underlying arsenic-induced reproductive toxicity. PMID:26973968

  19. Arsenic Toxicity in Male Reproduction and Development.

    PubMed

    Kim, Yoon-Jae; Kim, Jong-Min

    2015-12-01

    Arsenic is a toxic metalloid that exists ubiquitously in the environment, and affects global health problems due to its carcinogenicity. In most populations, the main source of arsenic exposure is the drinking water. In drinking water, chronic exposure to arsenic is associated with increased risks of various cancers including those of skin, lung, bladder, and liver, as well as numerous other non-cancer diseases including gastrointestinal and cardiovascular diseases, diabetes, and neurologic and cognitive problems. Recent emerging evidences suggest that arsenic exposure affects the reproductive and developmental toxicity. Prenatal exposure to inorganic arsenic causes adverse pregnancy outcomes and children's health problems. Some epidemiological studies have reported that arsenic exposure induces premature delivery, spontaneous abortion, and stillbirth. In animal studies, inorganic arsenic also causes fetal malformation, growth retardation, and fetal death. These toxic effects depend on dose, route and gestation periods of arsenic exposure. In males, inorganic arsenic causes reproductive dysfunctions including reductions of the testis weights, accessory sex organs weights, and epididymal sperm counts. In addition, inorganic arsenic exposure also induces alterations of spermatogenesis, reductions of testosterone and gonadotrophins, and disruptions of steroidogenesis. However, the reproductive and developmental problems following arsenic exposure are poorly understood, and the molecular mechanism of arsenic-induced reproductive toxicity remains unclear. Thus, we further investigated several possible mechanisms underlying arsenic-induced reproductive toxicity. PMID:26973968

  20. Approaches to Increase Arsenic Awareness in Bangladesh: An Evaluation of an Arsenic Education Program

    ERIC Educational Resources Information Center

    George, Christine Marie; Factor-Litvak, Pam; Khan, Khalid; Islam, Tariqul; Singha, Ashit; Moon-Howard, Joyce; van Geen, Alexander; Graziano, Joseph H.

    2013-01-01

    The objective of this study was to design and evaluate a household-level arsenic education and well water arsenic testing intervention to increase arsenic awareness in Bangladesh. The authors randomly selected 1,000 study respondents located in 20 villages in Singair, Bangladesh. The main outcome was the change in knowledge of arsenic from…

  1. Arsenic Toxicity to Juvenile Fish: Effects of Exposure Route, Arsenic Speciation, and Fish Species

    EPA Science Inventory

    Arsenic toxicity to juvenile rainbow trout and fathead minnows was evaluated in 28-day tests using both dietborne and waterborne exposures, both inorganic and organic arsenic species, and both a live diet and an arsenic-spiked pellet diet. Effects of inorganic arsenic on rainbow...

  2. Phytoremediation of arsenic contaminated soil by arsenic accumulators: a three year study.

    PubMed

    Raj, Anshita; Singh, Nandita

    2015-03-01

    To investigate whether phytoremediation can remove arsenic from the contaminated area, a study was conducted for three consecutive years to determine the efficiency of Pteris vittata, Adiantum capillus veneris, Christella dentata and Phragmites karka, on arsenic removal from the arsenic contaminated soil. Arsenic concentrations in the soil samples were analysed after harvesting in 2009, 2010 and 2011 at an interval of 6 months. Frond arsenic concentrations were also estimated in all the successive harvests. Fronds resulted in the greatest amount of arsenic removal. Root arsenic concentrations were analysed in the last harvest. Approximately 70 % of arsenic was removed by P. vittata which was recorded as the highest among the four plant species. However, 60 % of arsenic was removed by A. capillus veneris, 55.1 % by C. dentata and 56.1 % by P. karka of arsenic was removed from the contaminated soil in 3 years. PMID:25666567

  3. Effect of organic matter amendment, arsenic amendment and water management regime on rice grain arsenic species.

    PubMed

    Norton, Gareth J; Adomako, Eureka E; Deacon, Claire M; Carey, Anne-Marie; Price, Adam H; Meharg, Andrew A

    2013-06-01

    Arsenic accumulation in rice grain has been identified as a major problem in some regions of Asia. A study was conducted to investigate the effect of increased organic matter in the soil on the release of arsenic into soil pore water and accumulation of arsenic species within rice grain. It was observed that high concentrations of soil arsenic and organic matter caused a reduction in plant growth and delayed flowering time. Total grain arsenic accumulation was higher in the plants grown in high soil arsenic in combination with high organic matter, with an increase in the percentage of organic arsenic species observed. The results indicate that the application of organic matter should be done with caution in paddy soils which have high soil arsenic, as this may lead to an increase in accumulation of arsenic within rice grains. Results also confirm that flooding conditions substantially increase grain arsenic. PMID:23466730

  4. Arsenic - Multiple Languages: MedlinePlus

    MedlinePlus

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Arsenic URL of this page: https://www.nlm.nih.gov/medlineplus/languages/arsenic.html Other topics A-Z A B ...

  5. Arsenic Speciation in Groundwater: Role of Thioanions

    EPA Science Inventory

    The behavior of arsenic in groundwater environments is fundamentally linked to its speciation. Understanding arsenic speciation is important because chemical speciation impacts reactivity, bioavailability, toxicity, and transport and fate processes. In aerobic environments arsen...

  6. Production of selenium-72 and arsenic-72

    DOEpatents

    Phillips, Dennis R.

    1993-01-01

    Methods for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72.

  7. Production of selenium-72 and arsenic-72

    DOEpatents

    Phillips, D.R.

    1993-04-20

    Methods are described for producing selenium-72, separating it from its daughter isotope arsenic-72, and generating multiple portions of a solution containing arsenic-72 from a reusable parent substance comprised of selenium-72.

  8. Rapid oxidation and immobilization of arsenic by contact glow discharge plasma in acidic solution.

    PubMed

    Jiang, Bo; Hu, Ping; Zheng, Xing; Zheng, Jingtang; Tan, Minghui; Wu, Mingbo; Xue, Qinzhong

    2015-04-01

    Arsenic is a priority pollutant in aquatic ecosystem and therefore the remediation of arsenic-bearing wastewater is an important environmental issue. This study unprecedentedly reported simultaneous oxidation of As(III) and immobilization of arsenic can be achieved using contact glow discharge process (CGDP). CGDP with thinner anodic wire and higher energy input were beneficial for higher As(V) production efficiency. Adding Fe(II) in CGDP system significantly enhanced the oxidation rate of As(III) due to the generations of additional OH and Fe(IV) species, accompanied with which arsenic can be simultaneously immobilized in one process. Arsenic immobilization can be favorably obtained at solution pH in the range of 4.0-6.0 and Fe(II) concentration from 250 to 1000 μM. The presence of organics (i.e., oxalic acid, ethanol and phenol) retarded the arsenic immobilization by scavenging OH or complexing Fe(III) in aqueous solution. On the basis of these results, a mechanism was proposed that the formed ionic As(V) rapidly coprecipitated with Fe(III) ions or was adsorbed on the ferric oxyhydroxides with the formation of amorphous ferric arsenate-bearing ferric oxyhydroxides. This CGDP-Fenton system was of great interest for engineered systems concerned with the remediation of arsenic containing wastewater. PMID:25600320

  9. Melanocytes and keratinocytes have distinct and shared responses to ultraviolet radiation and arsenic.

    PubMed

    Cooper, K L; Yager, J W; Hudson, L G

    2014-01-30

    The rise of melanoma incidence in the United States is a growing public health concern. A limited number of epidemiology studies suggest an association between arsenic levels and melanoma risk. Arsenic acts as a co-carcinogen with ultraviolet radiation (UVR) for the development of squamous cell carcinoma and proposed mechanisms include generation of oxidative stress by arsenic and UVR and inhibition of UVR-induced DNA repair by arsenic. In this study, we investigate similarities and differences in response to arsenic and UVR in keratinocytes and melanocytes. Normal melanocytes are markedly more resistant to UVR-induced cytotoxicity than normal keratinocytes, but both cell types are equally sensitive to arsenite. Melanocytes were more resistant to arsenite and UVR stimulation of superoxide production than keratinocytes, but the concentration of arsenite necessary to inhibit the activity of the DNA repair protein poly(ADP-ribose)polymerase and enhance retention of UVR-induced DNA damage was essentially equivalent in both cell types. These findings suggest that although melanocytes are less sensitive than keratinocytes to initial UVR-mediated DNA damage, both of these important target cells in the skin share a mechanism related to arsenic inhibition of DNA repair. These findings suggest that concurrent chronic arsenic exposure could promote retention of unrepaired DNA damage in melanocytes and act as a co-carcinogen in melanoma. PMID:24270004

  10. Arsenic round the world: a review.

    PubMed

    Mandal, Badal Kumar; Suzuki, Kazuo T

    2002-08-16

    This review deals with environmental origin, occurrence, episodes, and impact on human health of arsenic. Arsenic, a metalloid occurs naturally, being the 20th most abundant element in the earth's crust, and is a component of more than 245 minerals. These are mostly ores containing sulfide, along with copper, nickel, lead, cobalt, or other metals. Arsenic and its compounds are mobile in the environment. Weathering of rocks converts arsenic sulfides to arsenic trioxide, which enters the arsenic cycle as dust or by dissolution in rain, rivers, or groundwater. So, groundwater contamination by arsenic is a serious threat to mankind all over the world. It can also enter food chain causing wide spread distribution throughout the plant and animal kingdoms. However, fish, fruits, and vegetables primarily contain organic arsenic, less than 10% of the arsenic in these foods exists in the inorganic form, although the arsenic content of many foods (i.e. milk and dairy products, beef and pork, poultry, and cereals) is mainly inorganic, typically 65-75%. A few recent studies report 85-95% inorganic arsenic in rice and vegetables, which suggest more studies for standardisation. Humans are exposed to this toxic arsenic primarily from air, food, and water. Thousands and thousands of people are suffering from the toxic effects of arsenicals in many countries all over the world due to natural groundwater contamination as well as industrial effluent and drainage problems. Arsenic, being a normal component of human body is transported by the blood to different organs in the body, mainly in the form of MMA after ingestion. It causes a variety of adverse health effects to humans after acute and chronic exposures such as dermal changes (pigmentation, hyperkeratoses, and ulceration), respiratory, pulmonary, cardiovascular, gastrointestinal, hematological, hepatic, renal, neurological, developmental, reproductive, immunologic, genotoxic, mutagenetic, and carcinogenic effects. Key research