WorldWideScience

Sample records for address arsenic manganese

  1. Adsorptive removal of manganese, arsenic and iron from groundwater

    Buamah, R.

    2009-01-01

    Arsenic, manganese and iron in drinking water at concentrations exceeding recommended guideline values pose health risks and aesthetic defects. Batch and pilot experiments on manganese adsorption equilibrium and kinetics using iron-oxide coated sand (IOCS), Aquamandix and other media have been investigated and modeled. Effect of manganese and iron loading on manganese removal and rate of oxidation of adsorbed iron and manganese have been studied. Aquamandix and IOCS demonstrated iron and mang...

  2. Purification of arsenic contaminated ground water using hydrated manganese dioxide

    An analytical methodology has been developed for the separation of arsenic from ground water using inorganic material in neutral medium. The separation procedure involves the quantitative retention of arsenic on hydrated manganese dioxide, in neutral medium. The validity of the separation procedure has been checked by a standard addition method and radiotracer studies. Neutron activation analysis (NAA), a powerful measurement technique, has been used for the quantitative determination of arsenic. (author)

  3. Multiple inorganic toxic substances contaminating the groundwater of Myingyan Township, Myanmar: Arsenic, manganese, fluoride, iron, and uranium

    Bacquart, Thomas [Better Life Laboratories, Calais, VT (United States); Frisbie, Seth [Better Life Laboratories, Calais, VT (United States); Department of Chemistry and Biochemistry, Norwich University, Northfield, VT (United States); Mitchell, Erika [Better Life Laboratories, Calais, VT (United States); Grigg, Laurie [Department of Earth and Environmental Science, Norwich University, Northfield, VT (United States); Cole, Christopher [Department of Chemistry and Biochemistry, Norwich University, Northfield, VT (United States); Small, Colleen [Vermont Department of Health Laboratory, Burlington, VT (United States); Sarkar, Bibudhendra, E-mail: bsarkar@sickkids.ca [Department of Molecular Structure and Function, The Research Institute of The Hospital for Sick Children, University of Toronto, Toronto, Ontario (Canada); Department of Biochemistry, University of Toronto, Toronto, Ontario (Canada)

    2015-06-01

    substances. - Highlights: • We analyzed Myanmar ground and surface waters for multiple inorganic contaminants. • Arsenic, manganese, fluoride, iron, or uranium exceeded safe levels in most wells. • Most wells contained more than one contaminant above health-based reference values. • Arsenic was positively and uranium negatively correlated with iron and manganese. • Mitigation, including testing and treatment, must address multiple contaminants.

  4. Multiple inorganic toxic substances contaminating the groundwater of Myingyan Township, Myanmar: Arsenic, manganese, fluoride, iron, and uranium

    substances. - Highlights: • We analyzed Myanmar ground and surface waters for multiple inorganic contaminants. • Arsenic, manganese, fluoride, iron, or uranium exceeded safe levels in most wells. • Most wells contained more than one contaminant above health-based reference values. • Arsenic was positively and uranium negatively correlated with iron and manganese. • Mitigation, including testing and treatment, must address multiple contaminants

  5. Effects of a manganese oxide-modified biochar composite on adsorption of arsenic in red soil.

    Yu, Zhihong; Zhou, Li; Huang, Yifan; Song, Zhengguo; Qiu, Weiwen

    2015-11-01

    The arsenic adsorption capacity of a manganese oxide-modified biochar composite (MBC), prepared by pyrolysis of a mixture of potassium permanganate and biochar, was investigated in red soil. Adsorption experiments using batch procedures were used to estimate the arsenic adsorption capacities of the absorbent materials. Adsorption and desorption isotherms, Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were used to characterise the prepared adsorbent materials, and a plausible mechanism for arsenic removal by MBC was proposed. Arsenic in red soil-MBC mixtures exhibited lower mobility than that in soils amended with pristine biochar. The improved removal performance of soil-MBC mixtures was attributed to a lower H/C ratio, higher O/C ratio, higher surface hydrophilicity, and higher surface sorption capacity, even though the impregnation of manganese oxide decreased the specific surface area of the biochar. Arsenic retention increased as the biochar content increased, mainly owing to an increase in soil pH. Several oxygenated functional groups, especially O-H, CO, Mn-O, and Si-O, participated in the adsorption process, and manganese oxides played a significant role in the oxidation of arsenic. This study highlights the potential of MBC as an absorbent to immobilise arsenic for use in contaminated land remediation in the red soils region. PMID:26320008

  6. Topographical Distribution of Arsenic, Manganese, and Selenium in the Normal Human Brain

    Larsen, Niels Agersnap; Pakkenberg, H.; Damsgaard, Else; Heydorn, Kaj

    1979-01-01

    The concentrations of arsenic, manganese and selenium per gram wet tissue weight were determined in samples from 24 areas of normal human brains from 5 persons with ages ranging from 15 to 81 years of age. The concentrations of the 3 elements were determined for each sample by means of neutron...... activation analysis with radiochemical separation. Distinct patterns of distribution were shown for each of the 3 elements. Variations between individuals were found for some but not all brain areas, resulting in coefficients of variation between individuals of about 30% for arsenic, 10% for manganese and 20......% for selenium. The results seem to indicate that arsenic is associated with the lipid phase, manganese with the dry matter and selenium with the aqueous phase of brain tissue....

  7. Simultaneous Determination of Arsenic, Manganese, and Selenium in Biological Materials by Neutron-Activation Analysis

    Heydorn, Kaj; Damsgaard, Else

    1973-01-01

    A new method was developed for the simultaneous determination of arsenic, manganese, and selenium in biological material by thermal-neutron activation analysis. The use of 81 mSe as indicator for selenium permitted a reduction of activation time to 1 hr for a 1 g sample, and the possibility of loss...... the ppM level in samples of biological tissue....

  8. Validation of In-Situ Iron-Manganese Oxide Coated Stream Pebbles as Sensors for Arsenic Source Monitoring

    Blake, J.; Peters, S. C.; Casteel, A.

    2013-12-01

    Locating nonpoint source contaminant fluxes can be challenging due to the inherent heterogeneity of source and of the subsurface. Contaminants such as arsenic are a concern for drinking water quality and ecosystem health. Arsenic contamination can be the result of several natural and anthropogenic sources, and therefore it can be difficult to trace and identify major areas of arsenic in natural systems. Identifying a useful source indicator for arsenic is a crucial step for environmental remediation efforts. Previous studies have found iron-manganese oxide coated streambed pebbles as useful source indicators due to their high attraction for heavy metals in water. In this study, pebbles, surface water at baseflow and nearby rocks were sampled from the Pennypack Creek and its tributaries, in southwestern Pennsylvania, to test the ability of coated streambed pebbles as environmental source indicators for arsenic. Quartz pebbles, 5-7 cm in diameter, were sampled to minimize elemental contamination from rock chemistry. In addition, quartz provides an excellent substrate for iron and manganese coatings to form. These coatings were leached from pebbles using 4M nitric acid with 0.1% concentrated hydrochloric acid. Following sample processing, analyses were performed using an ICP-MS and the resulting data were spatially organized using ArcGIS software. Arsenic, iron and manganese concentrations in the leachate are normalized to pebble surface area and each location is reported as a ratio of arsenic to iron and manganese. Results suggest that iron-manganese coated stream pebbles are useful indicators of arsenic location within a watershed.

  9. Multiple inorganic toxic substances contaminating the groundwater of Myingyan Township, Myanmar: arsenic, manganese, fluoride, iron, and uranium.

    Bacquart, Thomas; Frisbie, Seth; Mitchell, Erika; Grigg, Laurie; Cole, Christopher; Small, Colleen; Sarkar, Bibudhendra

    2015-06-01

    In South Asia, the technological and societal shift from drinking surface water to groundwater has resulted in a great reduction of acute diseases due to water borne pathogens. However, arsenic and other naturally occurring inorganic toxic substances present in groundwater in the region have been linked to a variety of chronic diseases, including cancers, heart disease, and neurological problems. Due to the highly specific symptoms of chronic arsenic poisoning, arsenic was the first inorganic toxic substance to be noticed at unsafe levels in the groundwater of West Bengal, India and Bangladesh. Subsequently, other inorganic toxic substances, including manganese, uranium, and fluoride have been found at unsafe levels in groundwater in South Asia. While numerous drinking water wells throughout Myanmar have been tested for arsenic, relatively little is known about the concentrations of other inorganic toxic substances in Myanmar groundwater. In this study, we analyzed samples from 18 drinking water wells (12 in Myingyan City and 6 in nearby Tha Pyay Thar Village) and 2 locations in the Ayeyarwaddy River for arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, fluoride, iron, mercury, manganese, molybdenum, nickel, lead, antimony, selenium, thallium, uranium, vanadium, and zinc. Concentrations of arsenic, manganese, fluoride, iron, or uranium exceeded health-based reference values in most wells. In addition, any given well usually contained more than one toxic substance at unsafe concentrations. While water testing and well sharing could reduce health risks, none of the wells sampled provide water that is entirely safe with respect to inorganic toxic substances. It is imperative that users of these wells, and users of other wells that have not been tested for multiple inorganic toxic substances throughout the region, be informed of the need for drinking water testing and the health consequences of drinking water contaminated with inorganic toxic

  10. Microbially-mediated thiocyanate oxidation and manganese cycling control arsenic mobility in groundwater at an Australian gold mine

    Horvath, A. S.; Baldisimo, J. G.; Moreau, J. W.

    2010-12-01

    Arsenic contamination of groundwater poses a serious environmental and human health problem in many regions around the world. Historical groundwater chemistry data for a Western-Central Victorian gold mine (Australia) revealed a strong inverse correlation between dissolved thiocyanate and iron(II), supporting the interpretation that oxidation of thiocyanate, a major groundwater contaminant by-product of cyanide-based gold leaching, was coupled to reductive dissolution of iron ox(yhydrox)ides in tailings dam sediments. Microbial growth was observed in this study in a selective medium using SCN- as the sole carbon and nitrogen source. The potential for use of SCN- as a tracer of mining contamination in groundwater was evaluated in the context of biological SCN- oxidation potential in the aquifer. Geochemical data also revealed a high positive correlation between dissolved arsenic and manganese, indicating that sorption on manganese-oxides most likely controls arsenic mobility at this site. Samples of groundwater and sediments along a roughly straight SW-NE traverse away from a large mine tailings storage facility, and parallel to the major groundwater flow direction, were analysed for major ions and trace metals. Groundwater from wells approaching the tailings along this traverse showed a nearly five-fold increase (roughly 25-125 ppb) in dissolved arsenic concentrations relative to aqueous Mn(II) concentrations. Thus, equivalent amounts of dissolved manganese released a five-fold difference in the amount of adsorbed arsenic. The interpretation that reductive dissolution of As-bearing MnO2 at the mine site has been mediated by groundwater (or aquifer) microorganisms is consistent with our recovery of synthetic birnessite-reducing enrichment cultures that were inoculated with As-contaminated groundwaters.

  11. Manganese

    Antibiotics (Quinolone antibiotics)Manganese can attach to quinolones in the stomach. This decreases the amount of quinolones that can be absorbed by the body. Taking manganese along with some antibiotics might ...

  12. Manganese

    ... osteoporosis). Taking manganese by mouth in combination with calcium, zinc, and copper seems to help reduce spinal bone ... research suggests that applying a dressing containing manganese, calcium, and zinc to chronic wounds for 12 weeks may improve ...

  13. Manganese

    Present article is devoted to manganese content in fluoride. The manganese content of some geologic deposits of Tajikistan was determined by means of chemical analysis. The mono mineral samples of fluorite of 5 geologic deposits of various mineralogical and genetic type was studied. The manganese content in fluorite of geologic deposits of various mineralogical and genetic type was defined.

  14. EVALUATING ARSENIC AND MANGANESE REMOVAL FROM WATER BY CHLORINE OXIDATION FOLLOWED BY CLARIFICATION

    V. G. R. Pires

    2015-06-01

    Full Text Available AbstractThis paper investigates the simultaneous removal of arsenic [As(V or As(III] and manganese [Mn(II] from natural waters of low and high turbidity by clarification (with polyaluminum chloride and aluminum sulfate as primary coagulants associated or not with chlorine pre-oxidation. The results showed that the clarification process exhibited low Mn(II removal, that varied from 6% to 18% and from 19% to 27% for natural waters of low and high turbidity, respectively. The use of chlorine as pre-oxidant increased Mn(II removal up to 77% and was associated with the formation of birnessite. Regarding As(V removal by clarification, particularly for high turbidity water, a concentration lower than that established by the National Drinking Water Quality Standards (10 μg.L-1 was achieved in almost all tests. Oxidation preceding the clarification led to AsIII removal efficiencies from 80% to 90% for both coagulants and types of water.

  15. Association of arsenic, cadmium and manganese exposure with neurodevelopment and behavioural disorders in children: A systematic review and meta-analysis

    The aim of this study was to analyse the scientific evidence published to date on the potential effects on neurodevelopment and behavioural disorders in children exposed to arsenic, cadmium and manganese and to quantify the magnitude of the effect on neurodevelopment by pooling the results of the different studies. We conducted a systematic review of original articles from January 2000 until March 2012, that evaluate the effects on neurodevelopment and behavioural disorders due to pre or post natal exposure to arsenic, cadmium and manganese in children up to 16 years of age. We also conducted a meta-analysis assessing the effects of exposure to arsenic and manganese on neurodevelopment. Forty-one articles that evaluated the effects of metallic elements on neurodevelopment and behavioural disorders met the inclusion criteria: 18 examined arsenic, 6 cadmium and 17 manganese. Most studies evaluating exposure to arsenic (13 of 18) and manganese (14 of 17) reported a significant negative effect on neurodevelopment and behavioural disorders. Only two studies that evaluated exposure to cadmium found an association with neurodevelopmental or behavioural disorders. The results of our meta-analysis suggest that a 50% increase of arsenic levels in urine would be associated with a 0.4 decrease in the intelligence quotient (IQ) of children aged 5–15 years. Moreover a 50% increase of manganese levels in hair would be associated with a decrease of 0.7 points in the IQ of children aged 6–13 years. There is evidence that relates arsenic and manganese exposure with neurodevelopmental problems in children, but there is little information on cadmium exposure. Few studies have evaluated behavioural disorders due to exposure to these compounds, and manganese is the only one for which there is more evidence of the existence of association with attention deficit disorder with hyperactivity. - Highlights: • We evaluated the association between As, Cd and Mn with neurodevelopment in

  16. Association of arsenic, cadmium and manganese exposure with neurodevelopment and behavioural disorders in children: A systematic review and meta-analysis

    Rodríguez-Barranco, Miguel [Andalusian School of Public Health (EASP), Granada (Spain); Lacasaña, Marina, E-mail: marina.lacasana.easp@juntadeandalucia.es [Andalusian School of Public Health (EASP), Granada (Spain); CIBER of Epidemiology and Public Health (CIBERESP), Madrid (Spain); Aguilar-Garduño, Clemente [CIBER of Epidemiology and Public Health (CIBERESP), Madrid (Spain); Centre Superior d' Investigació en Salut Pública, Conselleria de Sanitat, Valencia (Spain); Alguacil, Juan [CIBER of Epidemiology and Public Health (CIBERESP), Madrid (Spain); Department of Environmental Biology and Public Health, University of Huelva, Huelva (Spain); Gil, Fernando [Department of Legal Medicine and Toxicology, University of Granada, Granada (Spain); González-Alzaga, Beatriz [Andalusian School of Public Health (EASP), Granada (Spain); Rojas-García, Antonio [CIBER of Epidemiology and Public Health (CIBERESP), Madrid (Spain)

    2013-06-01

    The aim of this study was to analyse the scientific evidence published to date on the potential effects on neurodevelopment and behavioural disorders in children exposed to arsenic, cadmium and manganese and to quantify the magnitude of the effect on neurodevelopment by pooling the results of the different studies. We conducted a systematic review of original articles from January 2000 until March 2012, that evaluate the effects on neurodevelopment and behavioural disorders due to pre or post natal exposure to arsenic, cadmium and manganese in children up to 16 years of age. We also conducted a meta-analysis assessing the effects of exposure to arsenic and manganese on neurodevelopment. Forty-one articles that evaluated the effects of metallic elements on neurodevelopment and behavioural disorders met the inclusion criteria: 18 examined arsenic, 6 cadmium and 17 manganese. Most studies evaluating exposure to arsenic (13 of 18) and manganese (14 of 17) reported a significant negative effect on neurodevelopment and behavioural disorders. Only two studies that evaluated exposure to cadmium found an association with neurodevelopmental or behavioural disorders. The results of our meta-analysis suggest that a 50% increase of arsenic levels in urine would be associated with a 0.4 decrease in the intelligence quotient (IQ) of children aged 5–15 years. Moreover a 50% increase of manganese levels in hair would be associated with a decrease of 0.7 points in the IQ of children aged 6–13 years. There is evidence that relates arsenic and manganese exposure with neurodevelopmental problems in children, but there is little information on cadmium exposure. Few studies have evaluated behavioural disorders due to exposure to these compounds, and manganese is the only one for which there is more evidence of the existence of association with attention deficit disorder with hyperactivity. - Highlights: • We evaluated the association between As, Cd and Mn with neurodevelopment in

  17. Arsenic enrichment in estuarine sediments-impact of iron and manganese mining

    Nair, M.; Joseph, T.; Balachandran, K.K.; Nair, K.K.C.; Paimpillii, J.S.

    River Mandovi and Zuari, Goa (west coast of India) are flowing through iron and manganese mining areas and are heavily used for iron and manganese ore transport. This region generates 25-30 million tons of mining rejects per year. The iron ore...

  18. Arsenic

    ... of countries, including Argentina, Bangladesh, Chile, China, India, Mexico, and the United States of America. Drinking-water, ... ingestion of inorganic arsenic include developmental effects, neurotoxicity, diabetes, pulmonary disease and cardiovascular disease. Arsenic-induced myocardial ...

  19. A study of drinking water of industrial area of sheikhupura with special concern to arsenic, manganese and chromium

    in our current study we focused our attention to analyze the drinking water of industrial area of Sheikhupura that is swarming with small and large industries. Previously no work has been reported related to this area. Samples were collected from the twelve different sites of the mentioned area for six months at frequency of once per fifteen days (map in Fig 1). The samples were analyzed under strict quality control conditions and ASTM (American Standard Testing Methods) methods were employed for strictly precise and accurate results. Four sites showed bacterial contamination, five sites indicated high level of TDS (Total Dissolved Solids) and conductivity. Only one site indicated elevated chromium level (0.6 mg/L), two depicted increased level of arsenic but five sites gave idea about the high level of manganese(highest average value 1.2 mg/L ) in the study area. (author)

  20. In situ co-adsorption of arsenic and iron/manganese ions on raw clays

    Doušová, B.; Lhotka, M.; Grygar, Tomáš; Machovič, V.; Herzogová, L.

    2011-01-01

    Roč. 54, č. 2 (2011), s. 166-171. ISSN 0169-1317 Institutional research plan: CEZ:AV0Z40320502 Keywords : Arsenic * Groundwater * Co-adsorption * Raw clays * Pre-modified clays * Fe/Mn Subject RIV: DD - Geochemistry Impact factor: 2.474, year: 2011

  1. Arsenic, iron, lead, manganese, and uranium concentrations in private bedrock wells in southeastern New Hampshire, 2012-2013

    Flanagan, Sarah M.; Belaval, Marcel; Ayotte, Joseph D.

    2014-01-01

    Trace metals, such as arsenic, iron, lead, manganese, and uranium, in groundwater used for drinking have long been a concern because of the potential adverse effects on human health and the aesthetic or nuisance problems that some present. Moderate to high concentrations of the trace metal arsenic have been identified in drinking water from groundwater sources in southeastern New Hampshire, a rapidly growing region of the State (Montgomery and others, 2003). During the past decade (2000–10), southeastern New Hampshire, which is composed of Hillsborough, Rockingham, and Strafford Counties, has grown in population by nearly 48,700 (or 6.4 percent) to 819,100. These three counties contain 62 percent of the State’s population but encompass only about 22 percent of the land area (New Hampshire Office of Energy and Planning, 2011). According to a 2005 water-use study (Hayes and Horn, 2009), about 39 percent of the population in these three counties in southeastern New Hampshire uses private wells as sources of drinking water, and these wells are not required by the State to be routinely tested for trace metals or other contaminants. Some trace metals have associated human-health benchmarks or nonhealth guidelines that have been established by the U.S. Environmental Protection Agency (EPA) to regulate public water supplies. The EPA has established a maximum contaminant level (MCL) of 10 micrograms per liter (μg/L) for arsenic (As) and a MCL of 30 μg/L for uranium (U) because of associated health risks (U.S. Environmental Protection Agency, 2012). Iron (Fe) and manganese (Mn) are essential for human health, but Mn at high doses may have adverse cognitive effects in children (Bouchard and others, 2011; Agency for Toxic Substances and Disease Registry, 2012); therefore, the EPA has issued a lifetime health advisory (LHA) of 300 μg/L for Mn. Recommended secondary maximum contaminant levels (SMCLs) for Fe (300 μg/L) and Mn (50 μg/L) were established primarily as

  2. Studies of arsenic mobilization with iron, manganese and copper in borehole sediments of the river padma

    Previous Research suggested that there is a strong interrelation between As, Fe and Mn in their Occurring, transport and exposure to the environment. In this context, a comparative study was conducted in this current experiment to correlate As, Fe, Cu and Mn by determining their concentration in sediments (upper and bore hole) at different depths in the river Padma. Six locations were selected as sampling sites from entering point (upstream) and end point (downstream) of the river Padma. Sampling was carried out by borehole technique at several depths ranging from 1 meter to 5 meters. The samples were digested with HCIO/sub 4/- HNO/sub 3/ acid mixture of ratio 2:3 in an acid digestion bomb. Arsenic was determined by HVG-AAS technique and Fe, Mn and Cu were determined by Flame-AAS technique. Large amount of Fe has been obtained, which has endorsed the previous assumptions of the relations of As with Fe. The small correlation value in case of As, Fe and Mn indicates that not all the minerals of arsenic and Mn but only hydroxides of Fe and Mn interfere with As. The small amount of Cu obtained indicated that any relation between sources and exposure of As and Cu and their interaction is yet to be found out. (author)

  3. Spatial variability of arsenic concentration in soils and plants, and its relationship with iron, manganese and phosphorus

    Hossain, M.B. [Soil Science Division, Bangladesh Institute of Nuclear Agriculture, P.O. Box 4, Mymensingh 2200 (Bangladesh)], E-mail: baktear@gmail.com; Jahiruddin, M. [Department of Soil Science, Bangladesh Agricultural University, Mymensingh 2202 (Bangladesh)], E-mail: m_jahiruddin@yahoo.com; Panaullah, G.M. [CIMMYT Bangladesh, House 18, Road 4, Sector 4, Uttara, Dhaka 1230 (Bangladesh)], E-mail: gmpanaullah@gmail.com; Loeppert, R.H. [Soil and Crop Sciences Department, Texas A and M University, College Station, TX 77843-2474 (United States)], E-mail: rloepper@ag.tamu.edu; Islam, M.R. [Department of Soil Science, Bangladesh Agricultural University, Mymensingh 2202 (Bangladesh)], E-mail: mrislam58@yahoo.com; Duxbury, J.M. [Department of Crop and Soil Sciences, Cornell University, Ithaka, NY 14853 (United States)], E-mail: jmd17@cornell.edu

    2008-12-15

    Spatial distribution of arsenic (As) concentrations of irrigation water, soil and plant (rice) in a shallow tube-well (STW) command area (8 ha), and their relationship with Fe, Mn and P were studied. Arsenic concentrations of water in the 110 m long irrigation channel clearly decreased with distance from the STW point, the range being 68-136 {mu}g L{sup -1}. Such decreasing trend was also noticed with Fe and P concentrations, but the trend for Mn concentrations was not remarkable. Concerning soil As, the concentration showed a decreasing tendency with distance from the pump. The NH{sub 4}-oxalate extractable As contributed 36% of total As and this amount of As was associated with poorly crystalline Fe-oxides. Furthermore only 22% of total As was phosphate extractable so that most of the As was tightly retained by soil constituents and was not readily exchangeable by phosphate. Soil As (both total and extractable As) was significantly and positively correlated with rice grain As (0.296 {+-} 0.063 {mu}g g{sup -1}, n = 56). Next to drinking water, rice could be a potential source of As exposure of the people living in the As affected areas of Bangladesh. - Arsenic concentrations of irrigation water, soil and rice decreased with distance from STW point and it was related with iron and phosphorus concentrations.

  4. Spatial variability of arsenic concentration in soils and plants, and its relationship with iron, manganese and phosphorus

    Spatial distribution of arsenic (As) concentrations of irrigation water, soil and plant (rice) in a shallow tube-well (STW) command area (8 ha), and their relationship with Fe, Mn and P were studied. Arsenic concentrations of water in the 110 m long irrigation channel clearly decreased with distance from the STW point, the range being 68-136 μg L-1. Such decreasing trend was also noticed with Fe and P concentrations, but the trend for Mn concentrations was not remarkable. Concerning soil As, the concentration showed a decreasing tendency with distance from the pump. The NH4-oxalate extractable As contributed 36% of total As and this amount of As was associated with poorly crystalline Fe-oxides. Furthermore only 22% of total As was phosphate extractable so that most of the As was tightly retained by soil constituents and was not readily exchangeable by phosphate. Soil As (both total and extractable As) was significantly and positively correlated with rice grain As (0.296 ± 0.063 μg g-1, n = 56). Next to drinking water, rice could be a potential source of As exposure of the people living in the As affected areas of Bangladesh. - Arsenic concentrations of irrigation water, soil and rice decreased with distance from STW point and it was related with iron and phosphorus concentrations

  5. Arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in feathers of Black-legged Kittiwake (Rissa tridactyla) and Black Oystercatcher (Haematopus bachmani) from Prince William Sound, Alaska

    Burger, Joanna [Division of Life Sciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey 08854-8082 (United States); Consortium for Risk Evaluation with Stakeholder Participation (CRESP), Piscataway, New Jersey 08854 (United States); Environmental and Occupational Health Sciences Institute (EOHSI), Piscataway, New Jersey 08854 (United States)], E-mail: burger@biology.rutgers.edu; Gochfeld, Michael [Consortium for Risk Evaluation with Stakeholder Participation (CRESP), Piscataway, New Jersey 08854 (United States); Environmental and Occupational Health Sciences Institute (EOHSI), Piscataway, New Jersey 08854 (United States); Environmental and Occupational Medicine, UMDNJ-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854 (United States); Sullivan, Kelsey [U.S. Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, Alaska 99503 (United States); P.O. Box 801, Bethel, Maine, 04217 (United States); Irons, David [U.S. Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, Alaska 99503 (United States); McKnight, Aly [P.O. Box 801, Bethel, Maine, 04217 (United States)

    2008-07-15

    Arsenic, cadmium, chromium, lead, manganese, mercury and selenium were analyzed in the feathers of Black-legged Kittiwakes (Rissa tridactyla) from Shoup Bay in Prince William Sound, Alaska to determine if there were age-related differences in metal levels, and in Black Oystercatchers (Haematopus bachmani)) from the same region to determine if there were differences in oiled and unoiled birds. Except for mercury, there were no age-related differences in metals levels in the feathers of kittiwakes. Kittiwakes over 13 years of age had the highest levels of mercury. There were no differences in levels of metals in the feathers of oystercatchers from oiled and unoiled regions of Prince William Sound. Except for mercury, the feathers of oystercatchers had significantly higher levels of all metals than those of kittiwakes. Levels of mercury in kittiwake feathers (mean of 2910 ng/g [ppb]) were within the range of many species of seabirds reported for other studies, and were generally below adverse effects levels.

  6. Reference values of cadmium, arsenic and manganese in blood and factors associated with exposure levels among adult population of Rio Branco, Acre, Brazil.

    Freire, Carmen; Koifman, Rosalina Jorge; Fujimoto, Denys; de Oliveira Souza, Vanessa Cristina; Barbosa, Fernando; Koifman, Sergio

    2015-06-01

    This study aimed to investigate the distribution and factors influencing blood levels of Cadmium (Cd), Arsenic (As), and Manganese (Mn), and to determine their reference values in a sample of blood donors residing in Rio Branco, capital city of Acre State, Brazil. Blood samples were collected from all blood donors attending the Central Hemotherapic Unit in Rio Branco between 2010 and 2011. Among these, 1183 donors (98.9%) answered to a questionnaire on sociodemographic and lifestyle factors. Blood metal concentrations were determined by atomic spectrometry. Association between Cd, As and Mn levels and donors' characteristics was examined by linear regression analysis. Reference values were estimated as the upper limit of the 95% confidence interval of the 95th percentile of metal levels. References values were 0.87 μg L(-1) for Cd, 9.87 μg L(-1) for As, and 29.32 μg L(-1) for Mn. Reference values of Cd and As in smokers were 2.66 and 10.86 μg L(-1), respectively. Factors contributing to increase Cd levels were smoking, ethnicity (non-white), and lower education, whereas drinking tea and non-bottled water were associated with lower Cd. Lower levels of As were associated with higher household income, living near industrial facilities, working in a glass factory, a compost plant or in metal mining activities. Risk factors for Mn exposure were not identified. In general, blood Cd concentrations were in the range of exposure levels reported for other people from the general population, whereas levels of As and Mn were higher than in other non-occupationally exposed populations elsewhere. PMID:25655821

  7. The role of nano-sized manganese coatings on bone char in removing arsenic(V) from solution: Implications for permeable reactive barrier technologies.

    Liu, Jing; He, Lile; Dong, Faqin; Hudson-Edwards, Karen A

    2016-06-01

    Although the removal of arsenic(V) (As(V)) from solution can be improved by forming metal-bearing coatings on solid media, there has been no research to date examining the relationship between the coating and As(V) sorption performance. Manganese-coated bone char samples with varying concentrations of Mn were created to investigate the adsorption and desorption of As(V) using batch and column experiments. Breakthrough curves were obtained by fitting the Convection-Diffusion Equation (CDE), and retardation factors were used to quantify the effects of the Mn coatings on the retention of As(V). Uncoated bone char has a higher retention factor (44.7) than bone char with 0.465 mg/g of Mn (22.0), but bone char samples with between 5.02 mg/g and 14.5 mg/g Mn have significantly higher retention factors (56.8-246). The relationship between retardation factor (Y) and Mn concentration (X) is Y = 15.1 X + 19.8. Between 0.2% and 0.6% of the sorbed As is desorbed from the Mn-coated bone char at an initial pH value of 4, compared to 30% from the uncoated bone char. The ability of the Mn-coated bone char to neutralize solutions increases with increased amounts of Mn on the char. The results suggest that using Mn-coated bone char in Permeable Reactive Barriers would be an effective method for remediating As(V)-bearing solutions such as acid mine drainage. PMID:27016809

  8. Interlaboratory comparison survey of the determination of chromium, manganese, iron, titanium in dust and arsenic, cadmium, cobalt and chromium in urine

    This report describes an intercomparison survey based on the Danish External Quality Assessment Scheme (DEQAS). The study was carried out in 1998 for 10 laboratories in a research project on assessment of levels and health effects of airborne particulate matter in mining, metal refining and metal working industries using nuclear and related analytical techniques. The project was co-ordinated by the IAEA. Eight laboratories measured chromium (Cr), manganese (Mn), iron (Fe) and titanium (Ti) in welding fume dust loaded on filters. Six laboratories measured arsenic (As), four laboratories measured cadmium (Cd), five laboratories measured cobalt (Co) and four laboratories measured chromium (Cr) in urine. The target values of the quality control materials were traceable to certified reference materials with respect to Cr in welding fume and As, Cd, Co and Cr in urine. For Mn, Fe and Ti in welding fume the target values were established based on values from reference laboratories and consensus values from several DEQAS rounds. For evaluating the analytical performance the z-score and En number were calculated as recommended in ISO 45. The judgement of laboratories according to the performance scores revealed that few laboratories could maintain an ideal z-score below 3 and an ideal En number below 1. Nearly all participants had a high precision in the reported results. This is a good basis for improvements. The deviations from the target values appear to be systematic, because the deviations for Mn, Fe, Ti in welding dust as well as for As, Cd, Co and Cr in urine were a linear function of the target values (ISO 5725 evaluation). The cause for this bias is unknown at present and might not be the same for all participants. It is necessary to look further into the cause for this bias. Therefore, validation of the methodologies and regularly use of certified reference materials are highly recommended. (author)

  9. A simple method based on ICP-MS for estimation of background levels of arsenic, cadmium, copper, manganese, nickel, lead, and selenium in blood of the Brazilian population.

    Nunes, Juliana A; Batista, Bruno L; Rodrigues, Jairo L; Caldas, Naise M; Neto, Jose A G; Barbosa, Fernando

    2010-01-01

    Throughout the world, biomonitoring has become the standard for assessing exposure of individuals to toxic elements as well as for responding to serious environmental public health problems. However, extensive biomonitoring surveys require rapid and simple analytical methods. Thus, a simple and high-throughput method is proposed for the determination of arsenic (As), cadmium (Cd), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), and selenium (Se) in blood samples by using inductively coupled plasma-mass spectrometry (ICP-MS). Prior to analysis, 200 microl of blood samples was mixed with 500 microl of 10% v/v tetramethylammonium hydroxide (TMAH) solution, incubated for 10 min, and subsequently diluted to 10 ml with a solution containing 0.05% w/v ethylenediamine tetraacetic acid (EDTA) + 0.005% v/v Triton X-100. After that, samples were directly analyzed by ICP-MS (ELAN DRC II). Rhodium was selected as an internal standard with matrix-matching calibration. Method detection limits were 0.08, 0.04, 0.5, 0.09, 0.12, 0.04, and 0.1 microg//L for As, Cd, Cu, Mn, Ni, Pb, and Se, respectively. Validation data are provided based on the analysis of blood samples from the trace elements inter-\\comparison program operated by the Institut National de Sante Publique du Quebec, Canada. Additional validation was provided by the analysis of human blood samples by the proposed method and by using electrothermal atomic absorption spectrometry (ETAAS). The method was subsequently applied for the estimation of background metal blood values in the Brazilian population. In general, the mean concentrations of As, Cd, Cu, Mn, Ni, Pb, and Se in blood were 1.1, 0.4, 890, 9.6, 2.1, 65.4, and 89.3 microg/L, respectively, and are in agreement with other global populations. Influences of age, gender, smoking habits, alcohol consumption, and geographical variation on the values were also considered. Smoking habits influenced the levels of Cd in blood. The levels of Cu, Mn, and Pb were

  10. 锰砂/石英砂滤池与纳滤膜组合工艺去除水中砷的研究%Study on the combined process of manganese sand/quartz sand filter and nanofiltration membrane to remove the arsenic in water

    郭成会; 张维佳; 夏圣骥

    2011-01-01

    In this paper by employing the combined process of manganese sand/quartz sand filter and nanofiltration membrane to remove the arsenic in water, and the arsenic removal effects of manganese sand/quartz sand, nanofiltration membrane (NF90, HL), and combined process of manganese sand/quartz sand and nanofiltration were studied. The result showed that As ( Ⅲ ) and As( V )could be removed effectively by manganese sand/quartz sand filtration, and the effluent arsenic concentration could be less than 50 μg/L when the influent arsenic concentration was 250 μg/L; nanofiltration membrane could remove As(V) more than 90%, but only remove As(Ⅲ)about 40~60%; combined process of manganese sand/quartz sand and nanofiltration had strong removal effect of arsenic in water, and the arsenic concentration in effluent was less than 10 μg/L,which demonstrated that the combined process was an ideal process to remove arsenic in water.%采用锰砂/石英砂滤池与纳滤膜组合工艺处理含砷水,考察锰砂/石英砂、纳滤膜(NF90、HL)、锰砂/石英砂滤池与纳滤膜组合工艺对水中砷的去除效果.结果表明,三价砷(As(Ⅲ))和五价砷(As(Ⅴ))经锰砂/石英砂过滤后能得到很好的去除,原水砷浓度250 μg/L,出水砷浓度小于50μg/L;纳滤膜对五价砷(As(Ⅴ))的去除能力很高,能达到90%以上,但是对三价砷(As(Ⅲ))的去除率不理想,为40%~60%;锰砂/石英砂复合滤池与纳滤膜组合工艺对水中砷有很好的去除效果,出水砷浓度均小于10μg/L,是理想的饮用水除砷方法.

  11. [Competitive Microbial Oxidation and Reduction of Arsenic].

    Yang, Ting-ting; Bai, Yao-hui; Liang, Jin-song; Huo, Yang; Wang, Ming-xing; Yuan, Lin-ijang

    2016-02-15

    Filters are widely applied in drinking water treatment plants. Our previous study, which explored the asenic redox in a filter of drinking water plant treating underground water, found that As3+ could be oxidized to As5+ by biogenic manganese oxides, while As5+ could be reduced to As3+ by some microbial arsenic reductases in the biofilter system. This microbial competition could influence the system stability and treatment efficiency. To explore its mechanism, this study selected a manganese-oxidizing bacterial strain (Pseudomonas sp. QJX-1) and a arsenic-reducing strain (Brevibacterium sp. LSJ-9) to investigate their competitive relationship in nutrient acquisition and arsenic redox in the presence of Mn2+, As3+ or As5+ The results revealed that the concentration and valence of Mn and As varied with different reaction time; biological manganese oxides dominated the arsenic redox by rapidly oxidizing the As3+ in the existing system and the As3+ generated by arsenic reductase into As. PCR and RT-PCR results indicated that the arsenic reductase (arsC) was inhibited by the manganese oxidase (cumA). The expression of 16S rRNA in QJX-1 was two orders of magnitude higher than that in LSJ-9, which implied QJX-1 was dominant in the bacterial growth. Our data revealed that hydraulic retention time was critical to the valence of arsenic in the effluent of filter in drinking water treatment plant. PMID:27363151

  12. Removal of arsenic from ground water samples collected from West Bengal, India

    Arsenic contamination in ground water is one of the major concerns in many parts of the world including Bangladesh and India. Considering the high toxicity of arsenic, World Health Organization (WHO) has set a provisional guideline value of 10 μg L-1 for arsenic in drinking water. Several methods have been adopted for the removal of arsenic from drinking water. Most of the methods fail to remove As(III), the most toxic form of arsenic. An extra oxidative treatment step is essential for effective removal of total arsenic. Manganese dioxide (MnO2) oxidizes As(III) to As(V). Removal of arsenic from water using manganese dioxide has been reported. During this work, removal of arsenic from ground water samples collected from arsenic contaminated area of West Bengal, India were carried out using MnO2

  13. Effect of bacterial mineralization of phytoplankton-derived phytodetritus on the release of arsenic, cobalt and manganese from muddy sediments in the Southern North Sea. A microcosm study.

    Gillan, David C; Pede, Annelies; Sabbe, Koen; Gao, Yue; Leermakers, Martine; Baeyens, Willy; Louriño Cabana, Beatriz; Billon, Gabriel

    2012-03-01

    Muddy sediments of the Belgian Continental Zone (BCZ) are contaminated by metals such as Co, As, Cd, Pb, and Ni. Previous studies have suggested that mineralization of phytodetritus accumulating each year on sediments might cause secondary contaminations of the overlying seawater (metal effluxes). The aim of the present research was to investigate these effluxes using a microcosm approach. Muddy sediments were placed in microcosms (diameter: 15 cm) and overlaid by phytodetritus (a mix of Phaeocystis globosa with the diatom Skeletonema costatum). The final suspension was 130.6 mg L(-1) (dw) and the final chlorophyll a content was 750 ± 35 μg L(-1) (mean ± SD). Natural seawater was used for controls. Microcosms were then incubated in the dark at 15°C during 7 days. Metals were monitored in overlying waters and microbial communities were followed using bacterial and nanoflagellate DAPI counts, thymidine incorporation, community level physiological profiling (CLPP) and fluorescein diacetate analysis (FDA). Benthic effluxes observed in sediments exposed to phytodetritus were always more elevated than those observed in controls. Large effluxes were observed for Mn, Co and As, reaching 1084 nmol m(-2)day(-1) (As), 512 nmol m(-2)day(-1) (Co), and 755 μmol m(-2)day(-1) (Mn). A clear link was established between heterotrophic microbial activity and metal effluxes. The onset of mineralization was very fast and started within 2h of deposition as revealed by CLPP. An increased bacterial production was observed after two days (8.7 mg Cm(-2)day(-2)) and the bacterial biomass appeared controlled by heterotrophic nanoflagellates. Calculations suggest that during phytoplankton blooms the microbial activity alone may release substantial amounts of dissolved arsenic in areas of the BCZ covered by muddy sediments. PMID:22281039

  14. Arsenic chemistry in soils and sediments

    Fendorf, S.; Nico, P.; Kocar, B.D.; Masue, Y.; Tufano, K.J.

    2009-10-15

    Arsenic is a naturally occurring trace element that poses a threat to human and ecosystem health, particularly when incorporated into food or water supplies. The greatest risk imposed by arsenic to human health results from contamination of drinking water, for which the World Health Organization recommends a maximum limit of 10 {micro}g L{sup -1}. Continued ingestion of drinking water having hazardous levels of arsenic can lead to arsenicosis and cancers of the bladder, skin, lungs and kidneys. Unfortunately, arsenic tainted drinking waters are a global threat and presently having a devastating impact on human health within Asia. Nearly 100 million people, for example, are presently consuming drinking water having arsenic concentrations exceeding the World Health Organization's recommended limit (Ahmed et al., 2006). Arsenic contamination of the environment often results from human activities such as mining or pesticide application, but recently natural sources of arsenic have demonstrated a devastating impact on water quality. Arsenic becomes problematic from a health perspective principally when it partitions into the aqueous rather than the solid phase. Dissolved concentrations, and the resulting mobility, of arsenic within soils and sediments are the combined result of biogeochemical processes linked to hydrologic factors. Processes favoring the partitioning of As into the aqueous phase, potentially leading to hazardous concentrations, vary extensively but can broadly be grouped into four categories: (1) ion displacement, (2) desorption (or limited sorption) at pH values > 8.5, (3) reduction of arsenate to arsenite, and (4) mineral dissolution, particularly reductive dissolution of Fe and Mn (hydr)oxides. Although various processes may liberate arsenic from solids, a transition from aerobic to anaerobic conditions, and commensurate arsenic and iron/manganese reduction, appears to be a dominant, but not exclusive, means by which high concentrations of

  15. Arsenic speciation in edible mushrooms.

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

    2014-12-16

    The fruiting bodies, or mushrooms, of terrestrial fungi have been found to contain a high proportion of the nontoxic arsenic compound arsenobetaine (AB), but data gaps include a limited phylogenetic diversity of the fungi for which arsenic speciation is available, a focus on mushrooms with higher total arsenic concentrations, and the unknown formation and role of AB in mushrooms. To address these, the mushrooms of 46 different fungus species (73 samples) over a diverse range of phylogenetic groups were collected from Canadian grocery stores and background and arsenic-contaminated areas. Total arsenic was determined using ICP-MS, and arsenic speciation was determined using HPLC-ICP-MS and complementary X-ray absorption spectroscopy (XAS). The major arsenic compounds in mushrooms were found to be similar among phylogenetic groups, and AB was found to be the major compound in the Lycoperdaceae and Agaricaceae families but generally absent in log-growing mushrooms, suggesting the microbial community may influence arsenic speciation in mushrooms. The high proportion of AB in mushrooms with puffball or gilled morphologies may suggest that AB acts as an osmolyte in certain mushrooms to help maintain fruiting body structure. The presence of an As(III)-sulfur compound, for the first time in mushrooms, was identified in the XAS analysis. Except for Agaricus sp. (with predominantly AB), inorganic arsenic predominated in most of the store-bought mushrooms (albeit with low total arsenic concentrations). Should inorganic arsenic predominate in these mushrooms from contaminated areas, the risk to consumers under these circumstances should be considered. PMID:25417842

  16. Simultaneous determination of arsenic, cadmium, calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in fertilizers by microwave acid digestion and inductively coupled plasma-optical emission spectrometry detection: single-laboratory validation of a modification and extension of AOAC 2006.03.

    Webb, Sharon; Bartos, James; Boles, Rhonda; Hasty, Elaine; Thuotte, Ethel; Thiex, Nancy J

    2014-01-01

    A single-laboratory validation study was conducted for the simultaneous determination of arsenic, cadmium, calcium, cobalt, copper, chromium, iron, lead, magnesium, manganese, molybdenum, nickel, selenium, and zinc in all major types of commercial fertilizer products by microwave digestion and inductively coupled plasma-optical emission spectroscopy analysis. This validation study proposes an extension and modification of AOAC 2006.03. The extension is the inclusion of calcium, copper, iron, magnesium, manganese, and zinc, and the modification is incorporation of hydrochloric acid in the digestion system. This dual acid digestion utilizes both hydrochloric and nitric acids in a 3 to 9 mL volume ratio/100 mL. In addition to 15 of the 30 original validation materials used in the 2006.03 collaborative study, National Institute of Standards and Technology Standard Reference Material 695 and Magruder 2009-06 were incorporated as accuracy materials. The main benefits of this proposed method are a significant increase in laboratory efficiency when compared to the use of both AOAC Methods 965.09 and 2006.03 to achieve the same objective and an enhanced recovery of several metals. PMID:25051614

  17. In-situ arsenic remediation in Carson Valley, Douglas County, west-central Nevada

    Paul, Angela P.; Maurer, Douglas K.; Stollenwerk, Kenneth G.; Welch, Alan H.

    2010-01-01

    Conventional arsenic remediation strategies primarily involve above-ground treatment that include costs involved in the disposal of sludge material. The primary advantages of in-situ remediation are that building and maintaining a large treatment facility are not necessary and that costs associated with the disposal of sludge are eliminated. A two-phase study was implemented to address the feasibility of in-situ arsenic remediation in Douglas County, Nevada. Arsenic concentrations in groundwater within Douglas County range from 1 to 85 micrograms per liter. The primary arsenic species in groundwater at greater than 250 ft from land surface is arsenite; however, in the upper 150 ft of the aquifer arsenate predominates. Where arsenite is the primary form of arsenic, the oxidation of arsenite to arsenate is necessary. The results of the first phase of this investigation indicated that arsenic concentrations can be remediated to below the drinking-water standard using aeration, chlorination, iron, and pH adjustment. Arsenic concentrations were remediated to less than 10 micrograms per liter in groundwater from the shallow and deep aquifer when iron concentrations of 3-6 milligrams per liter and pH adjustments to less than 6 were used. Because of the rapid depletion of dissolved oxygen, the secondary drinking-water standards for iron (300 micrograms per liter) and manganese (100 micrograms per liter) were exceeded during treatment. Treatment was more effective in the shallow well as indicated by a greater recovery of water meeting the arsenic standard. Laboratory and field tests were included in the second phase of this study. Laboratory column experiments using aquifer material indicated the treatment process followed during the first phase of this study will continue to work, without exceeding secondary drinking-water standards, provided that groundwater was pre-aerated and an adequate number of pore volumes treated. During the 147-day laboratory experiment, no

  18. Linking Microbial Activity with Arsenic Fate during Cow Dung Disposal of Arsenic-Bearing Wastes

    Clancy, T. M.; Reddy, R.; Tan, J.; Hayes, K. F.; Raskin, L.

    2014-12-01

    To address widespread arsenic contamination of drinking water sources numerous technologies have been developed to remove arsenic. All technologies result in the production of an arsenic-bearing waste that must be evaluated and disposed in a manner to limit the potential for environmental release and human exposure. One disposal option that is commonly recommended for areas without access to landfills is the mixing of arsenic-bearing wastes with cow dung. These recommendations are made based on the ability of microorganisms to create volatile arsenic species (including mono-, di-, and tri-methylarsine gases) to be diluted in the atmosphere. However, most studies of environmental microbial communities have found only a small fraction (wastes produced during drinking water treatment in West Bengal, India. Arsenic in gaseous, aqueous, and solid phases was measured. Consistent with previous reports, less than 0.02% of the total arsenic present was volatilized. A much higher amount (~5%) of the total arsenic was mobilized into the liquid phase. Through the application of molecular tools, including 16S rRNA sequencing and quantification of gene transcripts involved in methanogenesis, this study links microbial community activity with arsenic fate in potential disposal environments. These results illustrate that disposal of arsenic-bearing wastes by mixing with cow dung does not achieve its end goal of promoting arsenic volatilization but rather appears to increase arsenic mobilization in the aqueous phase, raising concerns with this approach.

  19. Manganese Countries

    Maria Sousa Galito

    2014-05-01

    Full Text Available Cheickna Bounajim Cissé wrote an article in Mars 2013 in the Journal Les Afriques N. º 237, suggesting a new acronym, MANGANESE, for the nine African countries: Morocco, Angola, Namibia, Ghana, Algeria, Nigeria, Egypt, South Africa and Ethiopia. According to Cissé, this group of African nations will be the fastest growing states in the region over the next few years. The purpose of this article is to test the pertinence of the acronym, discuss the credibility and reliability of the future prospects of these countries by comparing selected socioeconomic and sociopolitical indicators based on the latest global rankings and trends. Likewise, the potential of Cissé's claim will be assessed, especially in relationship to drug trafficking and terrorism that may put their recent sustainability in danger now and in the future.

  20. Mobilization of arsenic from subsurface sediments by effect of bicarbonate ions in groundwater.

    Anawar, Hossain M; Akai, Junji; Sakugawa, Hiroshi

    2004-02-01

    Arsenic leaching by bicarbonate ions has been investigated in this study. Subsurface sediment samples from Bangladesh were treated with different carbonate and bicarbonate ions and the results demonstrate that the arsenic leaching efficiency of the carbonate solutions decreased in the order of Na2CO3>NaHCO3>BaCO3>MnCO3. Sodium carbonate and bicarbonate ions extracted arsenic most efficiently; Na2CO3 leached maximum 118.12 microg/l of arsenic, and NaHCO3, 94.56 microg/l of arsenic from the Ganges delta sediments after six days of incubation. The arsenic concentrations extracted in the batch experiments correlated very well with the bicarbonate concentrations. The kinetics study of arsenic release indicates that arsenic-leaching rate increased with reaction time in bicarbonate solutions. Bicarbonate ions can extract arsenic from sediment samples in both oxic and anoxic conditions. A linear relationship found between arsenic contents in core samples and those in leachates suggests that dissolved arsenic concentration in groundwater is related to the amount of arsenic in aquifer sediments. In batch experiment, bicarbonate solutions effectively extracted arsenic from arsenic adsorbed iron oxyhydroxide, reflecting that bicarbonate solutions may mobilize arsenic from iron and manganese oxyhydroxide in sediments that are ubiquitous in subsurface core samples. Carbonate ion may form complexes on the surface sites of iron hydroxide and substitute arsenic from the surface of minerals and sediments resulting in release of arsenic to groundwater. Like in the batch experiment, arsenic and bicarbonate concentrations in groundwater of Bangladesh correlated very well. Therefore, bicarbonate leaching is presumed to be one important mechanism to mobilize arsenic in bicarbonate dominated reducing aquifer of Bangladesh and other parts of the world as well. PMID:14602108

  1. Multivariate analysis of the heterogeneous geochemical processes controlling arsenic enrichment in a shallow groundwater system.

    Huang, Shuangbing; Liu, Changrong; Wang, Yanxin; Zhan, Hongbin

    2014-01-01

    The effects of various geochemical processes on arsenic enrichment in a high-arsenic aquifer at Jianghan Plain in Central China were investigated using multivariate models developed from combined adaptive neuro-fuzzy inference system (ANFIS) and multiple linear regression (MLR). The results indicated that the optimum variable group for the AFNIS model consisted of bicarbonate, ammonium, phosphorus, iron, manganese, fluorescence index, pH, and siderite saturation. These data suggest that reductive dissolution of iron/manganese oxides, phosphate-competitive adsorption, pH-dependent desorption, and siderite precipitation could integrally affect arsenic concentration. Analysis of the MLR models indicated that reductive dissolution of iron(III) was primarily responsible for arsenic mobilization in groundwaters with low arsenic concentration. By contrast, for groundwaters with high arsenic concentration (i.e., > 170 μg/L), reductive dissolution of iron oxides approached a dynamic equilibrium. The desorption effects from phosphate-competitive adsorption and the increase in pH exhibited arsenic enrichment superior to that caused by iron(III) reductive dissolution as the groundwater chemistry evolved. The inhibition effect of siderite precipitation on arsenic mobilization was expected to exist in groundwater that was highly saturated with siderite. The results suggest an evolutionary dominance of specific geochemical process over other factors controlling arsenic concentration, which presented a heterogeneous distribution in aquifers. Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of Environmental Science and Health, Part A, to view the supplemental file. PMID:24345245

  2. Manganese laser using manganese chloride as lasant

    Chen, C. J.

    1974-01-01

    A manganese vapor laser utilizing manganese chloride as a lasant has been observed and investigated. Lasing is attained by means of two consecutive electrical discharges. The maximum laser output is obtained at a vapor pressure of about 3 torr, a temperature of 680 C, and a time delay between electrical discharges of 150 microsec. The maximum energy density is 1.3 microjoule per cu cm.

  3. Earth Abides Arsenic Biotransformations

    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.

  4. Earth Abides Arsenic Biotransformations

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

    2014-01-01

    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 ...

  5. Cryptic exposure to arsenic

    Rossy Kathleen; Janusz Christopher; Schwartz Robert

    2005-01-01

    Arsenic is an odorless, colorless and tasteless element long linked with effects on the skin and viscera. Exposure to it may be cryptic. Although human intake can occur from four forms, elemental, inorganic (trivalent and pentavalent arsenic) and organic arsenic, the trivalent inorganic arsenicals constitute the major human hazard. Arsenic usually reaches the skin from occupational, therapeutic, or environmental exposure, although it still may be employed as a poison. Occupations involving ne...

  6. Naturally occurring radioactive elements, arsenic and other metals in drinking water from private wells

    island of Gotland, where the bedrock is dominated by Silurian limestones, the majority of the water samples showed boron concentrations far exceeding the provisional guide line value 500 μg/l set by WHO. Metals like lead, cadmium, nickel and chromium are only rarely found in harmful concentrations in Swedish drinking-water. A conclusion of the results from this study is that ordinary analyses of physico-chemical and microbiological parameters as well as radon-222, should be complemented with analyses of metals including uranium and arsenic, especially in waters from drilled wells in bedrock. A direct finding from this study is that radium-226 accumulates in some types of common water filters, which are often used to decrease iron and manganese. With arsenic concentrations in the drinking water exceeding the guide line 10 μg/l, actions should be taken to reduce the concentrations below this limit. Recent tests by the National Board of Health and Welfare of Sweden have shown that adsorption and ion exchange can reduce arsenic in drinking water up to 98 %. This project has shown that arsenic accumulates to a large degree in common water filters installed to remove iron and manganese. This study gives an overview of how drinking water, extracted from private wells, is influenced by various elements that occur naturally in our environment. New problem areas such as a radiation dose from lead-210 and polonium-210 have been identified. Information campaigns addressing different target groups, like county councils and municipalities, are necessary to inform well owners about the issues on radon, uranium, arsenic, fluoride and water filters. Additional studies are needed to further increase our knowledge on radioactive elements, arsenic and other possibly harmful elements in drinking water. A further mapping of lead-210 and polonium-210 occurrence in drinking water would allow for better estimates o

  7. Distribution of arsenic in groundwater in the area of Chalkidiki, Northern Greece

    An integrate study aiming at the occurrence and distribution of arsenic in groundwater in the area of Chalkidiki, Northern Greece has been carried out. Groundwater samples from public water supply wells and private wells were analysed for arsenic and other quality parameters (T, pH, EC, Ca, Mg, Na, K, Cl, HCO3, NO3, SO4, B, Fe, Mn). Arsenic showed high spatial variation; ranged from 0.001 to 1.840 mg/L. Almost 65% of the examined groundwaters exhibit arsenic concentrations higher than the maximum concentration limit of 0.010 mg/L, proposed for water intended for human consumption. Correlation analysis and principal component analysis were employed to find out possible relationships among the examined parameters and groundwater samples. Arsenic is highly correlated with potassium, boron, bicarbonate, sodium, manganese and iron suggesting common geogenic origin of these elements and conditions that enhance their mobility. Three groups of groundwater with different physicochemical characteristics were found in the study area: (a) groundwater with extremely high arsenic concentrations (1.6-1.9 mg/L) and high temperature (33-42 deg. C) from geothermal wells, (b) groundwater with relatively high arsenic concentrations (>0.050 mg/L), lower temperatures and relatively high concentrations of major ions, iron and manganese and, (c) groundwater with low arsenic concentrations that fulfil the proposed limits for dinking water

  8. Massive acute arsenic poisonings.

    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

  9. Arsenic speciation in arsenic-rich Brazilian soils from gold mining sites under anaerobic incubation

    De Mello, J. W. V.; Talbott, J.L.; Scott, J.; Roy, W.R.; Stucki, J.W.

    2007-01-01

    Background. Arsenic speciation in environmental samples is essential for studying toxicity, mobility and bio-transformation of As in aquatic and terrestrial environments. Although the inorganic species As(III) and As(V) have been considered dominant in soils and sediments, organisms are able to metabolize inorganic forms of arsenic into organo-arsenic compounds. Arsenosugars and methylated As compounds can be found in terrestrial organisms, but they generally occur only as minor constituents. We investigated the dynamics of arsenic species under anaerobic conditions in soils surrounding gold mining areas from Minas Gerais State, Brazil to elucidate the arsenic biogeochemical cycle and water contamination mechanisms. Methods. Surface soil samples were collected at those sites, namely Paracatu Formation, Banded Iron Formation and Riacho dos Machados Sequence, and incubated in CaCl2 2.5 mmol L-1 suspensions under anaerobic conditions for 1, 28, 56 and 112 days. After that, suspensions were centrifuged and supernatants analyzed for soluble As species by IC-ICPMS and HPLC-ICPMS. Results. Easily exchangeable As was mainly arsenite, except when reducible manganese was present. Arsenate was mainly responsible for the increase in soluble arsenic due to the reductive dissolution of either iron or manganese in samples from the Paracatu Formation and Riacho dos Machados Sequence. On the other hand, organic species of As dominated in samples from the Banded Iron Formation during anaerobic incubation. Discussion. Results are contrary to the expectation that, in anaerobic environments, As release due to the reductive dissolution of Fe is followed by As(V) reduction to As(III). The occurrence of organo-arsenic species was also found to be significant to the dynamics of soluble arsenic, mainly in soils from the Banded Iron Formation (BIF), under our experimental conditions. Conclusions. In general, As(V) and organic As were the dominant species in solution, which is surprising

  10. Arsenic Trioxide Injection

    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 ...

  11. Electrochemical arsenic remediation for rural Bangladesh

    Addy, Susan Amrose [Univ. of California, Berkeley, CA (United States)

    2008-01-01

    Arsenic in drinking water is a major public health problem threatening the lives of over 140 million people worldwide. In Bangladesh alone, up to 57 million people drink arsenic-laden water from shallow wells. ElectroChemical Arsenic Remediation(ECAR) overcomes many of the obstacles that plague current technologies and can be used affordably and on a small-scale, allowing for rapid dissemination into Bangladesh to address this arsenic crisis. In this work, ECAR was shown to effectively reduce 550 - 580 μg=L arsenic (including both As[III]and As[V]in a 1:1 ratio) to below the WHO recommended maximum limit of 10 μg=L in synthetic Bangladesh groundwater containing relevant concentrations of competitive ions such as phosphate, silicate, and bicarbonate. Arsenic removal capacity was found to be approximately constant within certain ranges of current density, but was found to change substantially between ranges. In order of decreasing arsenic removal capacity, the pattern was: 0.02 mA=cm2> 0.07 mA=cm2> 0.30 - 1.1 mA=cm2> 5.0 - 100 mA=cm2. Current processing time was found to effect arsenic removal capacity independent of either charge density or current density. Electrode polarization studies showed no passivation of the electrode in the tested range (up to current density 10 mA=cm2) and ruled out oxygen evolution as the cause of decreasing removal capacity with current density. Simple settling and decantation required approximately 3 days to achieve arsenic removal comparable to filtration with a 0.1 mu m membrane. X-ray Absorption Spectroscopy (XAS) showed that (1) there is no significant difference in the arsenic removal mechanism of ECAR during operation at different current densities and (2) the arsenic removal mechanism in ECAR is consistent with arsenate adsorption onto a homogenous Fe(III)oxyhydroxide similar in structure to 2-line ferrihydrite. ECAR effectively reduced high arsenic concentrations (100

  12. Electrochemical arsenic remediation for rural Bangladesh

    Addy, Susan Amrose

    2009-01-01

    Arsenic in drinking water is a major public health problem threatening the lives of over 140 million people worldwide. In Bangladesh alone, up to 57 million people drink arsenic-laden water from shallow wells. ElectroChemical Arsenic Remediation(ECAR) overcomes many of the obstacles that plague current technologies and can be used affordably and on a small-scale, allowing for rapid dissemination into Bangladesh to address this arsenic crisis. In this work, ECAR was shown to effectively reduce 550 - 580 mu g=L arsenic (including both As[III]and As[V]in a 1:1 ratio) to below the WHO recommended maximum limit of 10 mu g=L in synthetic Bangladesh groundwater containing relevant concentrations of competitive ions such as phosphate, silicate, and bicarbonate. Arsenic removal capacity was found to be approximately constant within certain ranges of current density, but was found to change substantially between ranges. In order of decreasing arsenic removal capacity, the pattern was: 0.02 mA=cm2> 0.07 mA=cm2> 0.30 - 1.1 mA=cm2> 5.0 - 100 mA=cm2. Current processing time was found to effect arsenic removal capacity independent of either charge density or current density. Electrode polarization studies showed no passivation of the electrode in the tested range (up to current density 10 mA=cm2) and ruled out oxygen evolution as the cause of decreasing removal capacity with current density. Simple settling and decantation required approximately 3 days to achieve arsenic removal comparable to filtration with a 0.1 mu m membrane. X-ray Absorption Spectroscopy (XAS) showed that (1) there is no significant difference in the arsenic removal mechanism of ECAR during operation at different current densities and (2) the arsenic removal mechanism in ECAR is consistent with arsenate adsorption onto a homogenous Fe(III)oxyhydroxide similar in structure to 2-line ferrihydrite. ECAR effectively reduced high arsenic concentrations (100 - 500 mu g=L) in real Bangladesh tube well water

  13. Arsenic removal from water

    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.

  14. Influence of groundwater composition on subsurface iron and arsenic removal.

    Moed, D H; van Halem, D; Verberk, J Q J C; Amy, G L; van Dijk, J C

    2012-01-01

    Subsurface arsenic and iron removal (SAR/SIR) is a novel technology to remove arsenic, iron and other groundwater components by using the subsoil. This research project investigated the influence of the groundwater composition on subsurface treatment. In anoxic sand column experiments, with synthetic groundwater and virgin sand, it was found that several dissolved substances in groundwater compete for adsorption sites with arsenic and iron. The presence of 0.01 mmol L(-1) phosphate, 0.2 mmol L(-1) silicate, and 1 mmol L(-1) nitrate greatly reduced the efficiency of SAR, illustrating the vulnerability of this technology in diverse geochemical settings. SIR was not as sensitive to other inorganic groundwater compounds, though iron retardation was limited by 1.2 mmol L(-1) calcium and 0.06 mmol L(-1) manganese. PMID:22678215

  15. Influence of groundwater composition on subsurface iron and arsenic removal

    Moed, David H.

    2012-06-01

    Subsurface arsenic and iron removal (SAR/SIR) is a novel technology to remove arsenic, iron and other groundwater components by using the subsoil. This research project investigated the influence of the groundwater composition on subsurface treatment. In anoxic sand column experiments, with synthetic groundwater and virgin sand, it was found that several dissolved substances in groundwater compete for adsorption sites with arsenic and iron. The presence of 0.01 mmol L -1phosphate, 0.2 mmol L -1 silicate, and 1 mmol L -1 nitrate greatly reduced the efficiency of SAR, illustrating the vulnerability of this technology in diverse geochemical settings. SIR was not as sensitive to other inorganic groundwater compounds, though iron retardation was limited by 1.2 mmol L -1 calcium and 0.06 mmol L -1 manganese. © IWA Publishing 2012.

  16. SEASONAL VARIATIONS OF ARSENIC AND OTHER TRACE ELEMENTS IN BAY MUSSELS 'MYTILUS EDULIS' (JOURNAL VERSION)

    The purposes of this study were to investigate seasonal variations of arsenic in a population of bay mussels (Mytilus edulis) and to compare results with variations of several other trace elements more commonly measured in environmental studies. Seasonal variations of manganese, ...

  17. GLI3 Links Environmental Arsenic Exposure and Human Fetal Growth

    Emily F. Winterbottom

    2015-06-01

    Full Text Available Although considerable evidence suggests that in utero arsenic exposure affects children's health, these data are mainly from areas of the world where groundwater arsenic levels far exceed the World Health Organization limit of 10 μg/L. We, and others, have found that more common levels of in utero arsenic exposure may also impact children's health. However, the underlying molecular mechanisms are poorly understood. To address this issue, we analyzed the expression of key developmental genes in fetal placenta in a birth cohort of women using unregulated water supplies in a US region with elevated groundwater arsenic. We identified several genes whose expression associated with maternal arsenic exposure in a fetal sex-specific manner. In particular, expression of the HEDGEHOG pathway component, GLI3, in female placentae was both negatively associated with arsenic exposure and positively associated with infant birth weight. This suggests that modulation of GLI3 in the fetal placenta, and perhaps in other fetal tissues, contributes to arsenic's detrimental effects on fetal growth. We showed previously that arsenic-exposed NIH3T3 cells have reduced GLI3 repressor protein. Together, these studies identify GLI3 as a key signaling node that is affected by arsenic, mediating a subset of its effects on developmental signaling and fetal health.

  18. Environmental Source of Arsenic Exposure

    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 ...

  19. Process for producing manganese-52

    The manganese is obtained by shooting at a target with He ions. Vanadium is suitable as target material. The reactions take place according to V(He,n)Mn, and V(He,2n)Mn. The isolation of the manganese is done by a chemical separation process. The manganese is used for radio pharmaceutical preparations. (orig./PW)

  20. Manganese biomining: A review.

    Das, A P; Sukla, L B; Pradhan, N; Nayak, S

    2011-08-01

    Biomining comprises of processing and extraction of metal from their ores and concentrates using microbial techniques. Currently this is used by the mining industry to extract copper, uranium and gold from low grade ores but not for low grade manganese ore in industrial scale. The study of microbial genomes, metabolites and regulatory pathways provide novel insights to the metabolism of bioleaching microorganisms and their synergistic action during bioleaching operations. This will promote understanding of the universal regulatory responses that the biomining microbial community uses to adapt to their changing environment leading to high metal recovery. Possibility exists of findings ways to imitate the entire process during industrial manganese biomining endeavor. This paper reviews the current status of manganese biomining research operations around the world, identifies factors that drive the selection of biomining as a processing technology, describes challenges in exploiting these innovations, and concludes with a discussion of Mn biomining's future. PMID:21632238

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

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

    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...

  2. The global menace of arsenic and its conventional remediation - A critical review.

    Sarkar, Arpan; Paul, Biswajit

    2016-09-01

    Arsenic is a ubiquitous element found in the earth crust with a varying concentration in the earth soil and water. Arsenic has always been under the scanner due to its toxicity in human beings. Contamination of arsenic in drinking water, which generally finds its source from arsenic-containing aquifers; has severely threatened billions of people all over the world. Arsenic poisoning is worse in Bangladesh where As(III) is abundant in waters of tube wells. Natural occurrence of arsenic in groundwater could result from both, oxidative and reductive dissolution. Geothermally heated water has the potential to liberate arsenic from surrounding rocks. Inorganic arsenic has been found to have more toxicity than the organic forms of arsenic. MMA and DMA are now been considered as the organic arsenic compounds having the potential to impair DNA and that is why MMA and DMA are considered as carcinogens. Endless efforts of researchers have elucidated the source, behavior of arsenic in various parts of the environment, mechanism of toxicity and various remediation processes; although, there are lots of areas still to be addressed. In this article, attempts have been made to lay bare an overview of geochemistry, toxicity and current removal techniques of arsenic together. PMID:27239969

  3. Arsenic Mobility and Availability in Sediments by Application of BCR Sequential Extractions Method

    Arsenic is a metalloid found in nature, both naturally and due to anthropogenic activities. Among them, mining works are an important source of arsenic release to the environment. Asturias is a region where important mercury mines were exploited, and in them arsenic occurs in para genesis with mercury minerals. The toxicity and mobility of this element depends on the chemical species it is found. Fractionation studies are required to analyze the mobility of this metalloid in soils and sediments. Among them, the proposed by the Bureau Community of Reference (BCR) is one of the most employed. This method attempts to divide up, by operationally defined stages, the amount of this element associated with carbonates (fraction 1), iron and manganese oxy hydroxides (fraction 2), organic matter and sulphides (fraction 3), and finally as the amount associated residual fraction to primary and secondary minerals, that is, from the most labile fractions to the most refractory ones. Fractionation of arsenic in sediments from two mines in Asturias were studied, La Soterrana and Los Rueldos. Sediments from La Soterrana showed high levels of arsenic in the non-residual phases, indicating that the majority of arsenic has an anthropogenic origin. By contrast, in sediments from Los Rueldos most of the arsenic is concentrated in the residual phase, indicating that this element remains bound to very refractory primary minerals, as is also demonstrated by the strong correlation of arsenic fractionation and the fractionation of elements present in refractory minerals, such as iron, aluminum and titanium. (Author) 51 refs.

  4. Manganese in sintered steels

    Based on the review of papers the results of the investigations of sintered manganese steels are presented. The effect of additional alloying elements such as copper, molybdenum and silicon on dimensional changes, density, tensile strength, hardness and elongation of such steels are also reported. (author)

  5. Drinking Water Fact Sheet: Arsenic

    Mesner, Nancy; Daniels, Barbara

    2010-01-01

    This fact sheet provides information about arsenic in drinking water. It includes sections about what arsenic is, where it comes from, health concerns from exposure, drinking water standards, how to know if there is arsenic in a water supply and how to reduce arsenic in drinking water.

  6. Arsenic in Food

    ... Biologics Animal & Veterinary Cosmetics Tobacco Products Food Home Food Foodborne Illness & Contaminants Metals Arsenic Share Tweet Linkedin Pin it More ... and previous or current use of arsenic-containing pesticides. Are there ... compounds in water, food, air, and soil: organic and inorganic (these together ...

  7. Arsenic and drinking water. Part 1. A review of the source, distribution and behaviour of arsenic in the environment; Arsen und Trinkwasser. Teil 1. Ein Ueberblick ueber Vorkommen, Verteilung und Verhalten von Arsen in der Umwelt

    Oberacker, F.; Maier, D. [Heinrich-Sontheimer-Lab., DVGW-Technologiezentrum Wasser, Karlsruhe (Germany); Maier, M. [Stadtwerke Karlsruhe GmbH, Karlsruhe (Germany)

    2002-11-01

    Arsenic is ubiquituously distributed in our environment and is subject to continuous bio-geochemical cycling. Besides the acute toxicity of arsenic its chronic effects are of special importance. The permanent uptake with drinking water for example might cause cancer. Today, arsenic compounds hardly serve as pesticides anymore, although chromated copper arsenate is still used to preserve wood. Furthermore, arsenic is used in the alloy, glass and semiconductor industry. The main part of the earths' arsenic resources are bound to sulfur in the lithosphere. By means of rock weathering and volcanism it is transferred into pedo-, hydro- and atmosphere, where it is mainly bound to oxygen. Microorganisms are able to methylate the arsenic, whereby gaseous arsenic compounds are carried into the atmosphere. Also, it is released from the lithosphere through anthropogenic mining activities, although only for a small part of the released amount useful applications exist. The arsenic behaviour in natural waters is closely related to sulfur on the one hand and to iron oxides on the other. Under strongly reducing conditions the arsenic is precipitated as sulfide, while under oxidising conditions it is adsorbed to the surfaces of iron oxides. Therefore, under aerobic conditions the arsenic concentrations of aqueous solutions are controlled by these adsorption processes rather than by the solubility of solid arsenic phases. Manganese oxides also play an important role as they are able to rapidly oxidise As(III) to As(V). These processes of release and fixation of arsenic in the nature must be studied carefully, because they are applied for arsenic elimination during drinking water production as well. (orig.)

  8. 21 CFR 184.1449 - Manganese citrate.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Manganese citrate. 184.1449 Section 184.1449 Food... Specific Substances Affirmed as GRAS § 184.1449 Manganese citrate. (a) Manganese citrate (Mn3(C6H5O7)2, CAS... manganese carbonate from manganese sulfate and sodium carbonate solutions. The filtered and...

  9. Complementary arsenic speciation methods: A review

    Nearing, Michelle M., E-mail: michelle.nearing@rmc.ca; Koch, Iris, E-mail: koch-i@rmc.ca; Reimer, Kenneth J., E-mail: reimer-k@rmc.ca

    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 arsenic-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. - Highlights: • HPLC–ICP-MS is the most common method used for arsenic speciation. • HPLC limitations include

  10. Complementary arsenic speciation methods: A review

    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 arsenic-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. - Highlights: • HPLC–ICP-MS is the most common method used for arsenic speciation. • HPLC limitations include

  11. IP Addressing

    2006-01-01

    tut quiz anim This interactive tutorial covers the following: The concept of halving a binary number space., Using the halving concept to explain how the Internet IP space is segmented into the A, B, and C address classifications., How the first octet ranges for the A, B, and C IP space are produced.In this tutorial, explanations are illustrated by simple animations. Students are asked to observe number patterns, and check their observations against automated 'answers.' There is a qu...

  12. Inaugural Address

    Syed Yousaf Raza Gilani

    2008-01-01

    Sardar Aseff Ahmad Ali, Deputy Chairman, Planning Commission, Dr Rashid Amjad, President, Pakistan Society of Development Economists, Honourable Ministers, Excellencies, Ladies and Gentlemen! It is indeed a privilege and honour to address this distinguished gathering of economists. I am very happy that this meeting is being attended by internationally acclaimed economists and academics from both within and outside the country. I am especially heartened to see that students of economics from a...

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

    Robin B. Harris

    2012-03-01

    Full Text Available 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.

  14. Manganese toxicity upon overexposure

    Crossgrove, Janelle; Zheng, Wei

    2004-01-01

    Manganese (Mn) is a required element and a metabolic byproduct of the contrast agent mangafodipir trisodium (MnDPDP). The Mn released from MnDPDP is initially sequestered by the liver for first-pass elimination, which allows an enhanced contrast for diagnostic imaging. The administration of intravenous Mn impacts its homeostatic balance in the human body and can lead to toxicity. Human Mn deficiency has been reported in patients on parenteral nutrition and in micronutrient studies. Mn toxicit...

  15. Manganese dipyridoxyl diphosphate:

    H, Brurok; Ardenkjær-Larsen, Jan Henrik; G, Hansson;

    1999-01-01

    Manganese dipyridoxyl diphosphate (MnDPDP) is a contrast agent for magnetic resonance imaging (MRI) of the liver. Aims of the study were to examine if MnDPDP possesses superoxide dismutase (SOD) mimetic activity in vitro, and if antioxidant protection can be demonstrated in an ex vivo rat heart m...... is concluded that MnDPDP and MnPLED possess SOD mimetic activities and may thereby protect the heart in oxidative stress. (C) 1999 Academic Press....

  16. Process for producing 52manganese

    The 52manganese is obtained by shooting at a target with 3He ions. Vanadium is suitable as target material. The reactions take place according to 50V(3He,n)52Mn, and 51V(3He,2n)52Mn. The isolation of the 52manganese is done by a chemical separation process. The 52manganese is used for radio pharmaceutical preparations. (DG)

  17. Keynote address

    This paper addresses various aspects of the bases underlying the nuclear third party liability regime, and also analyses the distinction between danger and risk and the manner in which damage caused by flood, mass unemployment (economic damage mainly) and certain diseases is dealt with in the absence of liability provisions similar to those applicable to nuclear incidents. It also is suggested that the State because of its duty under the Basic Law to ensure adequate energy supplies, should be co-responsible for liability questions along with the nuclear operator. (NEA)

  18. Complementary arsenic speciation methods: A review

    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.

  19. MODIFICATION OF CARBONACEOUS ADSORBENTS WITH MANGANESE COMPOUNDS

    Irina Ginsari; Larisa Postolachi; Vasile Rusu; Oleg Petuhov; Tatiana Goreacioc; Tudor Lupascu; Raisa Nastas

    2015-01-01

    Four series of samples containing manganese supported carbonaceous adsorbents were prepared. Obtained results reveal the importance of surface chemistry of carbonaceous adsorbents on the manganese loading.

  20. USEPA Arsenic Demonstration Program

    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.

  1. Welcome Address

    2001-01-01

    @@  On behalf of the International Life Sciences Institute, I welcome you to Beijing and to the Third Asian Conference on Food Safety and Nutrition. Many of you will remember the first Asian conference on Food Safety held in Kuala Lumpur in 1990 and the second held in Bangkok in 1994. These meetings have been so successful that ILSI made the commitment to host such a conference periodically in order to provide a forum to share the latest information and to set new goals and priorities.   This year, we have broadened the scope of the agenda to include issues on nutrition. I want to thank all of our co-sponsors and members of the Planning Committee for preparing such a comprehensive and timely program. Some of the issues and challenges facing Asia that will be addressed at this meeting are:

  2. Opening address

    The impact of the Chernobyl accident on health has been dramatic but different than expected. It has posed a tremendous health, social and economic burden on the people of Belarus, the Russian Federation and Ukraine. Now the picture of the impact of the accident on health and environment is clearer and the agenda can further move towards development and focused health programmes. The work of the Chernobyl Forum, which allowed this important objective to be reached, is an example of the multiplied added value that different United Nations agencies working together can achieve when addressing complex problems affecting large communities in an independent, comprehensive and credible way. This model should be the basis for future action with the Member States towards reconstruction, development and better health

  3. EXAFS study on arsenic species and transformation in arsenic hyperaccumulator

    HUANG Zechun; CHEN Tongbin; LEI Mei; HU Tiandou; HUANG Qifei

    2004-01-01

    Synchrotron radiation extended X-ray absorption fine structure (SR EXAFS) was employed to study the transformation of coordination environment and the redox speciation of arsenic in a newly discovered arsenic hyperaccumulator, Cretan brake (Pteris cretica L. var nervosa Thunb). It showed that the arsenic in the plant mainly coordinated with oxygen, except that some arsenic coordinated with S as As-GSH in root. The complexation of arsenic with GSH might not be the predominant detoxification mechanism in Cretan brake. Although some arsenic in root presented as As(V) in Na2HAsO4 treatments, most of arsenic in plant presented as As(III)-O in both treatments, indicating that As(V) tended to be reduced to As(III) after it was taken up into the root, and arsenic was kept as As(III) when it was transported to the above-ground tissues. The reduction of As(V) primarily proceeded in the root.

  4. Inaugural address

    Joshi, P. S.

    2014-03-01

    From jets to cosmos to cosmic censorship P S Joshi Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India E-mail: psj@tifr.res.in 1. Introduction At the outset, I should like to acknowledge that part of the title above, which tries to capture the main flavour of this meeting, and has been borrowed from one of the plenary talks at the conference. When we set out to make the programme for the conference, we thought of beginning with observations on the Universe, but then we certainly wanted to go further and address deeper questions, which were at the very foundations of our inquiry, and understanding on the nature and structure of the Universe. I believe, we succeeded to a good extent, and it is all here for you in the form of these Conference Proceedings, which have been aptly titled as 'Vishwa Mimansa', which could be possibly translated as 'Analysis of the Universe'! It is my great pleasure and privilege to welcome you all to the ICGC-2011 meeting at Goa. The International Conference on Gravitation and Cosmology (ICGC) series of meetings are being organized by the Indian Association for General Relativity and Gravitation (IAGRG), and the first such meeting was planned and conducted in Goa in 1987, with subsequent meetings taking place at a duration of about four years at various locations in India. So, it was thought appropriate to return to Goa to celebrate the 25 years of the ICGC meetings. The recollections from that first meeting have been recorded elsewhere here in these Proceedings. The research and teaching on gravitation and cosmology was initiated quite early in India, by V V Narlikar at the Banares Hindu University, and by N R Sen in Kolkata in the 1930s. In course of time, this activity grew and gained momentum, and in early 1969, at the felicitation held for the 60 years of V V Narlikar at a conference in Ahmedabad, P C Vaidya proposed the formation of the IAGRG society, with V V Narlikar being the first President. This

  5. Manganese Neurotoxicity in Oreochromis niloticus

    Annabelle Herrera; Elena Catap

    1992-01-01

    Manganese is not an acutely hazardous environmental contaminant at low levels, but increased dose produces serious degenerative disorders in Oreochromis niloticus. Sublethal exposure of fry to 2000 mg/L manganese chloride for eight days displays evidences of poisoning, and hard hit is the brain. Light microscopy shows appearance of gaps between brain layers and cell destruction. Electron microscopy shows damage to subcellular structures.

  6. Opening Address

    Yamada, T.

    2014-12-01

    Ladies and Gentlemen, it is my great honor and pleasure to present an opening address of the 3rd International Workshop on "State of the Art in Nuclear Cluster Physics"(SOTANCP3). On the behalf of the organizing committee, I certainly welcome all your visits to KGU Kannai Media Center belonging to Kanto Gakuin University, and stay in Yokohama. In particular, to whom come from abroad more than 17 countries, I would appreciate your participations after long long trips from your homeland to Yokohama. The first international workshop on "State of the Art in Nuclear Cluster Physics", called SOTANCP, was held in Strasbourg, France, in 2008, and the second one was held in Brussels, Belgium, in 2010. Then the third workshop is now held in Yokohama. In this period, we had the traditional 10th cluster conference in Debrecen, Hungary, in 2012. Thus we have the traditional cluster conference and SOTANCP, one after another, every two years. This obviously shows our field of nuclear cluster physics is very active and flourishing. It is for the first time in about 10 years to hold the international workshop on nuclear cluster physics in Japan, because the last cluster conference held in Japan was in Nara in 2003, about 10 years ago. The president in Nara conference was Prof. K. Ikeda, and the chairpersons were Prof. H. Horiuchi and Prof. I. Tanihata. I think, quite a lot of persons in this room had participated at the Nara conference. Since then, about ten years passed. So, this workshop has profound significance for our Japanese colleagues. The subjects of this workshop are to discuss "the state of the art in nuclear cluster physics" and also discuss the prospect of this field. In a couple of years, we saw significant progresses of this field both in theory and in experiment, which have brought better and new understandings on the clustering aspects in stable and unstable nuclei. I think, the concept of clustering has been more important than ever. This is true also in the

  7. Opening address

    Full text: Honourable Representatives of His Majesty King Mohammed VI and of the Government of Morocco, representatives of sponsoring organizations, distinguished participants, on behalf of the Director General of the IAEA, it is my pleasure and privilege to welcome you to this International Conference on National Infrastructures for Radiation Safety: Towards Effective and Sustainable Systems. I would like to express my sincere appreciation to His Majesty King Mohammed VI for his patronage, to the Government of Morocco and the University Mohammed V, Agdal, for hosting this conference in the beautiful and historic city of Rabat, and to the local organizers for their diligent planning and gracious hospitality. I would also like to thank the four organizations that are co-operating with the IAEA in holding this conference: the World Health Organization, the Pan American Health Organization, the International Labour Organization, the European Commission and the OECD/Nuclear Energy Agency. National infrastructure for radiation safety has emerged as an issue of international concern over the last two decades. Systematic and strategic consideration of infrastructure has become widely recognized as an essential prerequisite for safety. The first IAEA conference to address the topic was in Munich, Germany, in 1990. The 1996 edition of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (known as the Basic Safety Standards or BSS) highlighted the issue, and the IAEA's technical co-operation Model Project for Upgrading Radiation Protection Infrastructure was introduced to help address it. The Model Project has helped, and continues to help, more than 85 IAEA Member States to work towards the goal of a radiation safety infrastructure in accordance with the Basic Safety Standards. A great deal has been achieved, but this work is not complete. Furthermore, not all States are members of the IAEA or the Model

  8. Keynote address

    This keynote address describes the reasons why Ontario restructured its electricity sector to include open market competition. Much effort, time, money and expertise have been devoted to developing the Ontario competitive market. The 1997 White Paper issued by the Ontario Ministry of Energy, Science and Technology was the first paper to express the urgent need for change because the old system was failing. Prices increased by 60 per cent between 1986 and 1993. Although governments imposed a price freeze, it is recognized that such prices freezes cannot be sustained. Between 1980 and 1986, Ontario Hydro's debt rose from $12 billion to over $30 billion. The cause was attributed to poor business performance which was putting the taxpayers at risk. The author states that the potential and social benefits of competitive electricity markets are significant. Opening the power markets improves the efficiency of electricity systems and offers significant benefits. It is noted that restructuring does not mean deregulation. The Ontario Energy Board and the Independent Market Operator continue to regulate the market to ensure its proper operation and to protect consumers. In a properly functioning competitive market, prices change in response to market conditions. Electricity prices have generally declined where competitive markets have been introduced in other jurisdictions around the world. The author also cautions that it is easy to create unfounded fears about a competitive market and cited California as an example. California's problems arose from a lack of generating capacity, regulation which discouraged new power generation, inadequate transmission capacity, lack of snow in the northeast where hydropower is produced, and a consumer price cap that encouraged power consumption at a time when supply was short. The author notes that these factors do not exist in Ontario and that the competitive market should not be abandoned

  9. Keynote address

    DOE biomass R ampersand D programs have the potential to provide America with both plentiful, clean-burning domestic transportation fuels and cost-competitive industrial and utility fuels, benefiting energy security in the United States. Biofuels developed under our programs will also help improve air quality, reduce greenhouse gases, reduce the large daily quantities of waste we produce, and revitalize rural America. These research motivations have been documented in the National Energy Strategy. DOE looks forward to expanding its biofuels research program and to forging a partnership with private sector for cost-shared commercialization of new fuels and vehicle technologies. Many alternative fuels (e.g., ethanol, methanol, compressed natural gas, propane, or electricity) are candidates for gaining market share. Indeed, there may be significant regional variation in the future fuel mix. Alcohol fuels from biomass, particularly ethanol, have the potential to make a major contribution. Currently, ethanol in the United States is almost entirely made from corn; and the limitations of that process are well known (e.g., costly feedstock, end product requiring subsidy to be competitive, use of fossil fuels in renewable feedstock production and processing, and potential adverse impact of corn ethanol production on the price of food). To address these concerns, the DOE biofuels program is pursuing an ambitious research program to develop the technologies needed to convert these crops into alternative transportation fuels, primarily cellulose-based ethanol and methanol. Program R ampersand D has reduced the estimated cost per gallon of cellulose-based ethanol from $3.60 in 1980 to the current $1.35, with a program goal of $0.60 by the year 2000. DOE is also investigating the thermochemical conversion of biomass to methanol. The program goal is to achieve commercial production of methanol (like ethanol) at the gasoline equivalent of $0.90 per gallon by the year 2000. 4 figs

  10. Opening address

    This opening address covers two main areas: first, a snapshot of the continuing threat and the recent changes having been made to the United Kingdom's counterterrorism structures to respond to it; and second, how the United Kingdom is combating nuclear terrorism through a range of measures covering physical security, decreasing vulnerability to attack and increasing resilience. Combating the threat of nuclear terrorism requires an international effort. Radiological and fissile materials are present throughout the world and, as such, it should be secured wherever it is found. All countries are encouraged to continue to enhance security and protection mechanisms for radiological and fissile material; and to develop contingency plans should the worst happen. The United Kingdom has responded to the very serious and real threat by consolidating and strengthening elements of its counterterrorist planning via the creation in May this year of the Office for Security and Counter-Terrorism (OSCT). These changes have been coupled with an unprecedented level of investment to enable the delivery of the United Kingdom counterterrorist strategy - known as CONTEST - through which we aim to (a) stop terrorist attacks; (b) where it cannot be stopped, to mitigate its impact; (c) strengthen our overall protection against terrorist attack; (d) stop people becoming terrorists or supporting violent extremism. In the case of radiological and nuclear terrorism, it is not sufficient merely to prepare for such an attack; one must also devote efforts to preventing such attacks in the first instance by intercepting dangerous materials before they reach their intended target; and by strengthening the protection of vulnerable places and detecting or mitigating any devices before they are placed or activated. As such, in terms of the United Kingdom's efforts on radiological and nuclear terrorism, there are three main strands to this work: physical protection of materials including the global

  11. Presidential address.

    Vohra, U

    1993-07-01

    The Secretary of India's Ministry of Health and Family Welfare serves as Chair of the Executive Council of the International Institute for Population Sciences in Bombay. She addressed its 35th convocation in 1993. Global population stands at 5.43 billion and increases by about 90 million people each year. 84 million of these new people are born in developing countries. India contributes 17 million new people annually. The annual population growth rate in India is about 2%. Its population size will probably surpass 1 billion by the 2000. High population growth rates are a leading obstacle to socioeconomic development in developing countries. Governments of many developing countries recognize this problem and have expanded their family planning programs to stabilize population growth. Asian countries that have done so and have completed the fertility transition include China, Japan, Singapore, South Korea, and Thailand. Burma, Malaysia, North Korea, Sri Lanka, and Vietnam have not yet completed the transition. Afghanistan, Bangladesh, Iran, Nepal, and Pakistan are half-way through the transition. High population growth rates put pressure on land by fragmenting finite land resources, increasing the number of landless laborers and unemployment, and by causing considerable rural-urban migration. All these factors bring about social stress and burden civic services. India has reduced its total fertility rate from 5.2 to 3.9 between 1971 and 1991. Some Indian states have already achieved replacement fertility. Considerable disparity in socioeconomic development exists among states and districts. For example, the states of Bihar, Madhya Pradesh, Rajasthan, and Uttar Pradesh have female literacy rates lower than 27%, while that for Kerala is 87%. Overall, infant mortality has fallen from 110 to 80 between 1981 and 1990. In Uttar Pradesh, it has fallen from 150 to 98, while it is at 17 in Kerala. India needs innovative approaches to increase contraceptive prevalence rates

  12. Acute and chronic arsenic toxicity

    Ratnaike, R.

    2003-01-01

    Arsenic toxicity is a global health problem affecting many millions of people. Contamination is caused by arsenic from natural geological sources leaching into aquifers, contaminating drinking water and may also occur from mining and other industrial processes. Arsenic is present as a contaminant in many traditional remedies. Arsenic trioxide is now used to treat acute promyelocytic leukaemia. Absorption occurs predominantly from ingestion from the small intestine, though minimal absorption o...

  13. Opening address

    and become more technical. Involving experts from all fields is then crucial for success. This perception is reflected in the goals of this meeting. It is designed as an extensive information exchange forum between decision makers, regulators, radiation and waste safety specialists, and the nuclear industry. It is this mix which promises high efficiency with respect to solving the problems that you are addressing. I am sure that the safe termination of practices involving radioactive materials during the decommissioning of nuclear installations is one of the major challenges that industrialized nations will have to face during the next decades

  14. Welcome Address

    Kiku, H.

    2014-12-01

    Ladies and Gentlemen, It is an honor for me to present my welcome address in the 3rd International Workshop on "State of the Art in Nuclear Cluster Physics"(SOTANCP3), as the president of Kanto Gakuin University. Particularly to those from abroad more than 17 countries, I am very grateful for your participation after long long trips from your home to Yokohama. On the behalf of the Kanto Gakuin University, we certainly welcome your visit to our university and stay in Yokohama. First I would like to introduce Kanto Gakuin University briefly. Kanto Gakuin University, which is called KGU, traces its roots back to the Yokohama Baptist Seminary founded in 1884 in Yamate, Yokohama. The seminary's founder was Albert Arnold Bennett, alumnus of Brown University, who came to Japan from the United States to establish a theological seminary for cultivating and training Japanese missionaries. Now KGU is a major member of the Kanto Gakuin School Corporation, which is composed of two kindergartens, two primary schools, two junior high schools, two senior high schools as well as KGU. In this university, we have eight faculties with graduate school including Humanities, Economics, Law, Sciences and Engineering, Architecture and Environmental Design, Human and Environmental Studies, Nursing, and Law School. Over eleven thousands students are currently learning in our university. By the way, my major is the geotechnical engineering, and I belong to the faculty of Sciences and Engineering in my university. Prof. T. Yamada, here, is my colleague in the same faculty. I know that the nuclear physics is one of the most active academic fields in the world. In fact, about half of the participants, namely, more than 50 scientists, come from abroad in this conference. Moreover, I know that the nuclear physics is related to not only the other fundamental physics such as the elementary particle physics and astrophysics but also chemistry, medical sciences, medical cares, and radiation metrology

  15. Opening address

    The opening address by the host country started by thanking to the International Atomic Energy Agency for holding this important scientific event in in Morocco. The themes to be considered by this conference are among the priorities of the Scientific Research Department in its endeavour to promote scientific research in the field of nuclear science and technology for peaceful uses in Morocco. By so doing, this Department is following and supporting the efforts being made by our country to provide training, and elaborate rules and regulations, and to create infrastructure, acquire material and, equipment and encourage qualified and active researchers. Hence, the convening of this conference responds to a strategic interest of our country, which, similar to other countries, is committed to the achievement of comprehensive and sustainable development for the protection of human kind and the environment. This is considered nowadays as a strategic and vital objective as it entails the protection of people from radiation and against all kinds of professional risks and health hazards. Morocco attaches great importance to radiation safety issues. Our country adhered to all international conventions related to nuclear safety. It is in the process of adapting its internal regulations to international norms and standards, and it is making progress towards the establishment of a national safety body which meets those norms and standards, with the assistance of the IAEA. For this purpose, a standing committee for the follow-up of nuclear affairs has been created on the basis of Royal Instructions, and placed under the authority of the Prime Minister. Its task is to serve as a think-tank on nuclear safety issues and to make proposals on ways and means of reinforcing radiation safety measures. It goes without saying that the peaceful uses of nuclear energy must meet the safety standards elaborated by the IAEA. However, we are convinced that the elaboration of safety standards

  16. Opening address

    Nuclear terrorism has been recognized as a potential threat to human security and economic prosperity since at least the 1970s. Evidence of Al Qaeda's interest in acquiring nuclear material came to light during the 1990s. However, it is since the attacks of 11 September 2001 that the risk of nuclear terrorist acts has come to be a widespread public and governmental concern, for understandable reasons, and that efforts to combat illicit trafficking, which could lead to nuclear or other radioactive materials falling into the hands of terrorists, have intensified. Six years on, it makes sense to take stock of what has been achieved in the combat to stem illicit trafficking and of where further actions - actions of individual States and cooperative international actions - might usefully be initiated. The IAEA has maintained an Illicit Trafficking Database since 1995. Information reported to this database confirms that concerns about illicit trafficking in nuclear material are justified. Database information points to persistent theft and loss of radioactive sources. States' international obligations relevant to international nuclear trafficking are based on the Convention on the Physical Protection of Nuclear Material (CPPNM), the International Convention for the Suppression of Acts of Nuclear Terrorism, the United Nations Security Council Resolution 1540, which deals with weapons of mass destruction, including nuclear weapons and non-State actors, and the United Nations Security Council Resolution 1375, which requires all States to take the necessary steps to prevent the commission of terrorist acts, including early warning to other States. In addition to these legally binding instruments, there is the non-binding Code of Conduct on the Safety and Security of Radioactive Sources, which Member States of the IAEA agreed in 2003. The Code addresses the establishment of an adequate system of regulatory control, from the production of radioactive sources to their final

  17. 21 CFR 184.1452 - Manganese gluconate.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Manganese gluconate. 184.1452 Section 184.1452 Food... Specific Substances Affirmed as GRAS § 184.1452 Manganese gluconate. (a) Manganese gluconate (C12H22MnO14... manganese carbonate with gluconic acid in aqueous medium and then crystallizing the product. (b)...

  18. 21 CFR 184.1461 - Manganese sulfate.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Manganese sulfate. 184.1461 Section 184.1461 Food... Specific Substances Affirmed as GRAS § 184.1461 Manganese sulfate. (a) Manganese sulfate (MnSO4·H2O, CAS... manganese compounds with sulfuric acid. It is also obtained as a byproduct in the manufacture...

  19. Long-distance transport, vacuolar sequestration and transcriptional responses induced by cadmium and arsenic

    Mendoza-Cózatl, David G.; Jobe, Timothy O.; Hauser, Felix; Schroeder, Julian I

    2011-01-01

    Iron, zinc, copper and manganese are essential metals for cellular enzyme functions while cadmium, mercury and the metalloid arsenic lack any biological function. Both, essential and non-essential metals and metalloids are extremely reactive and toxic. Therefore, plants have acquired specialized mechanisms to sense, transport and maintain essential metals within physiological concentrations and to detoxify non-essential metals and metalloids. This review focuses on the recent identification o...

  20. Attenuation of arsenic in a karst subterranean stream and correlation with geochemical factors: a case study at Lihu, South China.

    Zhang, Liankai; Yang, Hui; Tang, Jiansheng; Qin, Xiaoqun; Yu, Au Yik

    2014-11-01

    Arsenic (As) pollutants generated by human activities in karst areas flow into subterranean streams and contaminate groundwater easily because of the unique hydrogeological characteristics of karst areas. To elucidate the reaction mechanisms of arsenic in karst subterranean streams, physical-chemical analysis was conducted by an inductively coupled plasma mass spectrometer and an X-ray fluorescence spectrometer. The results show that inorganic species account for most of the total arsenic, whereas organic arsenic is not detected or occurs in infinitesimal amounts. As(III) accounts for 51.0%±9.9% of the total inorganic arsenic. Arsenic attenuation occurs and the attenuation rates of total As, As(III) and As(V) in the Lihu subterranean stream are 51%, 36% and 59%, respectively. To fully explain the main geochemical factors influencing arsenic attenuation, SPSS 13.0 and CANOCO 4.5 bundled with CanoDraw for Windows were used for simple statistical analysis and redundancy analysis (RDA). Eight main factors, i.e., sediment iron (SFe), sediment aluminum (SAl), sediment calcium (SCa), sediment organic matter (SOM), sediment manganese (SMn), water calcium (WCa(2+)), water magnesium (WMg(2+)), and water bicarbonate ion (WHCO3(-)) were extracted from thirteen indicators. Their impacts on arsenic content rank as: SFe>SCa>WCa(2+)>SAl>WHCO3(-)>SMn>SOM>WMg(2+). Of these factors, SFe, SAl, SCa, SOM, SMn, WMg(2+) and WCa(2+) promote arsenic attenuation, whereas WHCO3(-) inhibits it. Further investigation revealed that the redox potential (Eh) and pH are adverse to arsenic removal. The dramatic distinction between karst and non-karst terrain is that calcium and bicarbonate are the primary factors influencing arsenic migration in karst areas due to the high calcium concentration and alkalinity of karst water. PMID:25458676

  1. Opening address

    Being fully aware of the IAEA's central and important roles in the field of nuclear security, Japan has cooperated closely with the IAEA in the field of nuclear security. One of Japan's efforts was holding a seminar on strengthening nuclear security in Asian countries in November 2006, making use of Japan's contribution to the IAEA Nuclear Security Fund. The seminar was organized for the first time in Asia to address nuclear security matters, in which more than 100 experts from 19 countries participated. Japan also hosted a seminar, aimed at promoting the accession to the international counterterrorism conventions and protocols, inviting government officials and experts from Asia Pacific countries. At the seminar, Japan presented its experience and lessons learned with regard to its ratification of relevant international conventions such as the International Convention for the Suppression of Acts of Nuclear Terrorism and the Convention on the Physical Protection of Nuclear Material. Japan has also provided assistance for capacity building in the field of physical protection measures, and is preparing three projects for Asian countries through the IAEA Nuclear Security Fund. In Thailand, Japan has a project aimed at improving physical protection of nuclear research facilities. In Vietnam, Japan plans to host a workshop on radiation detection equipment for border officials and is also preparing for a seminar aimed at capacity building of control on nuclear material in Vietnam. Japan is committed to continue its efforts to make the IAEA Comprehensive Safeguards Agreement together with an Additional Protocol the universally accepted verification standard for the peaceful use undertakings of the Nuclear Non-Proliferation Treaty. Japan's basic policy on bilateral nuclear cooperation agreements is as follows. Considering the dual nature of nuclear material and technology, Japan is of the view that three Ss, that is, S for 'safeguards' (non-proliferation), S for 'safety

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

    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,...

  3. Arsenic: The Silent Killer

    Foster, Andrea (USGS)

    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.

  4. Arsenic hyperaccumulator Pteris Vittata L. and its arsenic accumulation

    2002-01-01

    An arsenic hyperaccumulator Pteris vittata L. (Chinese brake) was first discovered in China by means of field survey and greenhouse cultivation. Field survey showed that Chinese brake had large accumulating capacity to arsenic; the orders of arsenic content in different parts of the fern were as follows: leaves>leafstalks>roots, which is totally different from that of ordinary plants; bioaccumulation coefficients of the above ground parts of the fern decreased as a power function of soil arsenic contents. In the control of pot trials with normal unpolluted soil containing 9 mg/kg of arsenic, the bioaccumulation coefficients of the above ground parts and rhizoids of Chinese brake were as high as 71 and 80 respectively. Greenhouse cultivation in the contaminated soil from mining areas has shown that more than 1 times greater arsenic can be accumulated in the leaves of the fern than that of field samples with the largest content of 5070 mg/kg As on a dry matter basis. During greenhouse cultivation, arsenic content in the leaves of the fern increased linearly with time prolonging. Not only has Chinese brake extraordinary tolerance and accumulation to arsenic, but it grew rapidly with great biomass, wide distribution and easy adaptation to different environmental conditions as well. Therefore, it has great potential in future remediation of arsenic contamination. It also demonstrates important value for studies of arsenic physiology and biochemistry such as arsenic absorption, translocation and detoxification mechanisms in plants.

  5. Manganese borohydride; synthesis and characterization

    Richter, Bo; Ravnsbæk, Dorthe B.; Tumanov, Nikolay; Filinchuk, Yaroslav; Jensen, Torben R.

    2015-01-01

    Solvent-based synthesis and characterization of α-Mn(BH4)2 and a new nanoporous polymorph of manganese borohydride, γ-Mn(BH4)2, via a new solvate precursor, Mn(BH4)2·1/2S(CH3)2, is presented. Manganese chloride is reacted with lithium borohydride in a toluene/dimethylsulfide mixture at room temperature, which yields halide and solvent-free manganese borohydride after extraction with dimethylsulfide (DMS) and subsequent removal of residual solvent. This work constitutes the first example of es...

  6. Arsenic Speciation of Terrestrial Invertebrates

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

    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.

  7. Manganese dipyridoxyl diphosphate:

    H, Brurok; Ardenkjær-Larsen, Jan Henrik; G, Hansson; S, Skarra; K, Berg; Laursen, Ib; P, Jynge

    1999-01-01

    Manganese dipyridoxyl diphosphate (MnDPDP) is a contrast agent for magnetic resonance imaging (MRI) of the liver. Aims of the study were to examine if MnDPDP possesses superoxide dismutase (SOD) mimetic activity in vitro, and if antioxidant protection can be demonstrated in an ex vivo rat heart...... model. Superoxide ((.)O(2)(-)) and hydroxyl radicals ((.)OH(-)) were generated in xanthine oxidase and Fenton reactions. Spin adducts with 5,5-dimethyl-1-pyrroline-N-oxide were detected by electron spin resonance spectroscopy. Contractile function and enzyme release were monitored in rat hearts during...... is concluded that MnDPDP and MnPLED possess SOD mimetic activities and may thereby protect the heart in oxidative stress. (C) 1999 Academic Press....

  8. Cooking rice in excess water reduces both arsenic and enriched vitamins in the cooked grain.

    Gray, Patrick J; Conklin, Sean D; Todorov, Todor I; Kasko, Sasha M

    2016-01-01

    This paper reports the effects of rinsing rice and cooking it in variable amounts of water on total arsenic, inorganic arsenic, iron, cadmium, manganese, folate, thiamin and niacin in the cooked grain. We prepared multiple rice varietals both rinsed and unrinsed and with varying amounts of cooking water. Rinsing rice before cooking has a minimal effect on the arsenic (As) content of the cooked grain, but washes enriched iron, folate, thiamin and niacin from polished and parboiled rice. Cooking rice in excess water efficiently reduces the amount of As in the cooked grain. Excess water cooking reduces average inorganic As by 40% from long grain polished, 60% from parboiled and 50% from brown rice. Iron, folate, niacin and thiamin are reduced by 50-70% for enriched polished and parboiled rice, but significantly less so for brown rice, which is not enriched. PMID:26515534

  9. High manganese non magnetic steel

    A high-manganese, non-magnetic steel is specified, having excellent weldability and machinability and suitable for use in the structural parts of electrical equipment or nuclear fusion equipment. (author)

  10. ARSENIC REMOVAL TREATMENT OPTIONS FOR SINGLE FAMILY HOMES

    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...

  11. Association of hypothyroidism with low-level arsenic exposure in rural West Texas

    It has been reported recently that a higher airborne arsenic level was correlated with higher urinary arsenic concentration and lower serum thyroxin level among urban policemen and rural highway workmen in Italy. The current study was to determine whether exposure to low-level arsenic groundwater (2–22 µg/L) is associated with hypothyroidism among 723 participants (118 male and 267 female Hispanics; 108 male and 230 female non-Hispanic whites, NHW) living in rural West Texas counties. Arsenic and iodine levels in their groundwater used for drinking and or cooking were estimated by the inverse distance weighted (IDW) interpolation technique. Groundwater arsenic was ≥8 µg/L in 36% of the subjects' wells while iodine concentration was <1 µg/L in 91% of their wells. Logistic regression analysis showed that arsenic in groundwater ≥8 µg/L and cumulative arsenic exposure (groundwater arsenic concentration multiplied by the number of years living in the current address) but not groundwater iodine concentration were significant predictors for hypothyroidism among Hispanics (p<0.05) but not NHW after adjusting for covariates such as age, gender, annual household income and health insurance coverage. The ethnic difference may be due to a marginally higher percentage of Hispanics (p=0.0622) who lived in areas with groundwater arsenic ≥8 µg/L compared with NHW. The prevalence of hypothyroidism was significantly higher in Hispanics or NHW of this rural cohort than the national prevalence. Measures should be taken to reduce arsenic in drinking water in order to prevent hypothyroidism in rural areas. - Highlights: • We determined if arsenic exposure is associated with hypothyroidism in rural Texas. • Groundwater arsenic level is associated with hypothyroidism among Hispanics only. • The rate of hypothyroidism in rural Texas was higher than the US general population

  12. Association of hypothyroidism with low-level arsenic exposure in rural West Texas

    Gong, Gordon, E-mail: gordon.gong@ttuhsc.edu [F. Marie Hall Institute for Rural and Community Health, Texas Tech University Health Sciences Center, Lubbock, TX (United States); Basom, Janet [F. Marie Hall Institute for Rural and Community Health, Texas Tech University Health Sciences Center, Lubbock, TX (United States); Department of Family and Community Medicine, Texas Tech University Health Sciences Center, Lubbock, TX (United States); Mattevada, Sravan [Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX (United States); Onger, Frederick [Department of Family and Community Medicine, Texas Tech University Health Sciences Center, Lubbock, TX (United States)

    2015-04-15

    It has been reported recently that a higher airborne arsenic level was correlated with higher urinary arsenic concentration and lower serum thyroxin level among urban policemen and rural highway workmen in Italy. The current study was to determine whether exposure to low-level arsenic groundwater (2–22 µg/L) is associated with hypothyroidism among 723 participants (118 male and 267 female Hispanics; 108 male and 230 female non-Hispanic whites, NHW) living in rural West Texas counties. Arsenic and iodine levels in their groundwater used for drinking and or cooking were estimated by the inverse distance weighted (IDW) interpolation technique. Groundwater arsenic was ≥8 µg/L in 36% of the subjects' wells while iodine concentration was <1 µg/L in 91% of their wells. Logistic regression analysis showed that arsenic in groundwater ≥8 µg/L and cumulative arsenic exposure (groundwater arsenic concentration multiplied by the number of years living in the current address) but not groundwater iodine concentration were significant predictors for hypothyroidism among Hispanics (p<0.05) but not NHW after adjusting for covariates such as age, gender, annual household income and health insurance coverage. The ethnic difference may be due to a marginally higher percentage of Hispanics (p=0.0622) who lived in areas with groundwater arsenic ≥8 µg/L compared with NHW. The prevalence of hypothyroidism was significantly higher in Hispanics or NHW of this rural cohort than the national prevalence. Measures should be taken to reduce arsenic in drinking water in order to prevent hypothyroidism in rural areas. - Highlights: • We determined if arsenic exposure is associated with hypothyroidism in rural Texas. • Groundwater arsenic level is associated with hypothyroidism among Hispanics only. • The rate of hypothyroidism in rural Texas was higher than the US general population.

  13. Rural methods to mitigate arsenic contaminated water

    Parajuli, Krishna

    2013-01-01

    Consumption of arsenic contaminated water is one of the burning issues in the rural world. Poor public awareness program about health effects of drinking arsenic contaminated water and the rural methods to mitigate this problem poses a great threat of arsenic poisoning many people of the rural world. In this thesis, arsenic removal efficiency and the working mechanism of four rural and economical arsenic mitigation technologies i.e. solar oxidation and reduction of arsenic (SORAS), Bucket tr...

  14. The effectiveness of water-treatment systems for arsenic used in 11 homes in Southwestern and Central Ohio, 2013

    Thomas, Mary Ann; Ekberg, Mike

    2016-01-01

    the raw water. In general, the treatment systems were less effective at treating higher concentrations of arsenic. For five sites with raw-water arsenic concentrations of 10–30 µg/L, the systems removed 65–81 percent of the arsenic, and the final concentrations were less than the maximum contamination level. For three sites with higher raw-water arsenic concentrations (50–75 µg/L), the systems removed 22–34 percent of the arsenic; and the final concentrations were 4–5 times more than the maximum contamination level. Other characteristics of the raw water may have affected the performance of treatment systems; in general, raw water with the higher arsenic concentrations also had higher pH, higher concentrations of organic carbon and ammonia, and more reducing (methanogenic) redox conditions.For sites with raw-water arsenic concentrations of 10–30 µg/L, two types of systems (reverse osmosis and oxidation/filtration) removed similar amounts of arsenic, but the quality of the treated water differed in other respects. Reverse osmosis caused substantial decreases in pH, alkalinity, and concentrations of most ions. On the other hand, oxidation/filtration using manganese-based media caused a large increase of manganese concentrations, from less than 50 µg/L in raw water to more than 700 µg/L in outflow from the oxidation filtration units.It is not known if the results of this study are widely applicable; the number of systems sampled was relatively small, and each system was sampled only once. Further study may be warranted to investigate whether available methods of arsenic removal are effective/practical for residential use in areas like Ohio, were groundwater with elevated arsenic concentrations is strongly reducing, and the predominant arsenic species is arsenite (As3+).

  15. Bog Manganese Ore: A Resource for High Manganese Steel Making

    Pani, Swatirupa; Singh, Saroj K.; Mohapatra, Birendra K.

    2016-05-01

    Bog manganese ore, associated with the banded iron formation of the Iron Ore Group (IOG), occurs in large volume in northern Odisha, India. The ore is powdery, fine-grained and soft in nature with varying specific gravity (2.8-3.9 g/cm3) and high thermo-gravimetric loss, It consists of manganese (δ-MnO2, manganite, cryptomelane/romanechite with minor pyrolusite) and iron (goethite/limonite and hematite) minerals with sub-ordinate kaolinite and quartz. It shows oolitic/pisolitic to globular morphology nucleating small detritus of quartz, pyrolusite/romanechite and hematite. The ore contains around 23% Mn and 28% Fe with around 7% of combined alumina and silica. Such Mn ore has not found any use because of its sub-grade nature and high iron content, and is hence considered as waste. The ore does not respond to any physical beneficiation techniques because of the combined state of the manganese and iron phases. Attempts have been made to recover manganese and iron value from such ore through smelting. A sample along with an appropriate charge mix when processed through a plasma reactor, produced high-manganese steel alloy having 25% Mn within a very short time (<10 min). Minor Mn content from the slag was recovered through acid leaching. The aim of this study has been to recover a value-added product from the waste.

  16. Extraction of manganese from electrolytic manganese residue by bioleaching.

    Xin, Baoping; Chen, Bing; Duan, Ning; Zhou, Changbo

    2011-01-01

    Extraction of manganese from electrolytic manganese residues using bioleaching was investigated in this paper. The maximum extraction efficiency of Mn was 93% by sulfur-oxidizing bacteria at 4.0 g/l sulfur after bioleaching of 9days, while the maximum extraction efficiency of Mn was 81% by pyrite-leaching bacteria at 4.0 g/l pyrite. The series bioleaching first by sulfur-oxidizing bacteria and followed by pyrite-leaching bacteria evidently promoted the extraction of manganese, witnessing the maximum extraction efficiency of 98.1%. In the case of sulfur-oxidizing bacteria, the strong dissolution of bio-generated sulfuric acid resulted in extraction of soluble Mn2+, while both the Fe2+ catalyzed reduction of Mn4+ and weak acidic dissolution of Mn2+ accounted for the extraction of manganese with pyrite-leaching bacteria. The chemical simulation of bioleaching process further confirmed that the acid dissolution of Mn2+ and Fe2+ catalyzed reduction of Mn4+ were the bioleaching mechanisms involved for Mn extraction from electrolytic manganese residues. PMID:21050747

  17. Bog Manganese Ore: A Resource for High Manganese Steel Making

    Pani, Swatirupa; Singh, Saroj K.; Mohapatra, Birendra K.

    2016-06-01

    Bog manganese ore, associated with the banded iron formation of the Iron Ore Group (IOG), occurs in large volume in northern Odisha, India. The ore is powdery, fine-grained and soft in nature with varying specific gravity (2.8-3.9 g/cm3) and high thermo-gravimetric loss, It consists of manganese (δ-MnO2, manganite, cryptomelane/romanechite with minor pyrolusite) and iron (goethite/limonite and hematite) minerals with sub-ordinate kaolinite and quartz. It shows oolitic/pisolitic to globular morphology nucleating small detritus of quartz, pyrolusite/romanechite and hematite. The ore contains around 23% Mn and 28% Fe with around 7% of combined alumina and silica. Such Mn ore has not found any use because of its sub-grade nature and high iron content, and is hence considered as waste. The ore does not respond to any physical beneficiation techniques because of the combined state of the manganese and iron phases. Attempts have been made to recover manganese and iron value from such ore through smelting. A sample along with an appropriate charge mix when processed through a plasma reactor, produced high-manganese steel alloy having 25% Mn within a very short time (<10 min). Minor Mn content from the slag was recovered through acid leaching. The aim of this study has been to recover a value-added product from the waste.

  18. Chronic arsenic poisoning from burning high-arsenic-containing coal in Guizhou, China.

    Liu, Jie; Zheng, Baoshan; Aposhian, H. Vasken; Zhou, Yunshu; Chen, Ming-liang; Zhang, Aihua; Waalkes, Michael P.

    2002-01-01

    Arsenic is an environmental hazard and the reduction of drinking water arsenic levels is under consideration. People are exposed to arsenic not only through drinking water but also through arsenic-contaminated air and food. Here we report the health effects of arsenic exposure from burning high arsenic-containing coal in Guizhou, China. Coal in this region has undergone mineralization and thus produces high concentrations of arsenic. Coal is burned inside the home in open pits for daily cooki...

  19. Transplacental Arsenic Carcinogenesis in Mice

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

    2007-01-01

    Our work has focused on the carcinogenic effects of in utero arsenic exposure in mice. Our data show 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 day 8 to 18 of gestation,...

  20. Determination of manganese content in aqueous solutions

    The three analytical methods used in the hydrogen-to-manganese cross-section ratio measurement were: volumetric determination of manganese, gravimetric analysis of manganous sulfate; and densimetric determination of manganous sulfate

  1. Nonequilibrium Thermodynamic Model of Manganese Carbonate Oxidation

    郝瑞霞; 彭省临

    1999-01-01

    Manganese carbonate can be converted to many kinds of manganese oxides when it is aerated in air and oxygen.Pure manganese carbonate can be changed into Mn3O4 and γ-MnOOH,and manganese carbonate ore can be converted to MnO2 under the air-aerating and oxygen-aerating circumstances.The oxidation process of manganese carbonate is a changing process of mineral association,and is also a converting process of valence of manganese itself.Not only equilibrium stat,but also nonequilibrium state are involved in this whole process,This process is an irreversible heterogeneous complex reaction,and oberys the nonequilibrium thermodynamic model,The oxidation rate of manganese cabonate is controlled by many factors,especially nonmanganese metallic ions which play an important role in the oxidation process of manganese carbonate.

  2. Evaluation of innovative arsenic treatment technologies :the arsenic water technology partnership vendors forums summary report.

    Everett, Randy L.; Siegel, Malcolm Dean; McConnell, Paul E.; Kirby, Carolyn (Comforce Technical Services, Inc.)

    2006-09-01

    The lowering of the drinking water standard (MCL) for arsenic from 50 {micro}g/L to 10 {micro}g/L in January 2006 could lead to significant increases in the cost of water for many rural systems throughout the United States. The Arsenic Water Technology Partnership (AWTP), a collaborative effort of Sandia National Laboratories, the Awwa Research Foundation (AwwaRF) and WERC: A Consortium for Environmental Education and Technology Development, was formed to address this problem by developing and testing novel treatment technologies that could potentially reduce the costs of arsenic treatment. As a member of the AWTP, Sandia National Laboratories evaluated cutting-edge commercial products in three annual Arsenic Treatment Technology Vendors Forums held during the annual New Mexico Environmental Health Conferences (NMEHC) in 2003, 2004 and 2005. The Forums were comprised of two parts. At the first session, open to all conference attendees, commercial developers of innovative treatment technologies gave 15-minute talks that described project histories demonstrating the effectiveness of their products. During the second part, these same technologies were evaluated and ranked in closed sessions by independent technical experts for possible use in pilot-scale field demonstrations being conducted by Sandia National Laboratories. The results of the evaluations including numerical rankings of the products, links to company websites and copies of presentations made by the representatives of the companies are posted on the project website at http://www.sandia.gov/water/arsenic.htm. This report summarizes the contents of the website by providing brief descriptions of the technologies represented at the Forums and the results of the evaluations.

  3. Adsorption kinetic of arsenates as water pollutant on iron, manganese and iron-manganese-modified clinoptilolite-rich tuffs

    Jimenez-Cedillo, M.J. [Instituto Nacional de Investigaciones Nucleares, Departamento de Quimica, A.P. 18-1027, Col, Escandon, Del, Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico); Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Colon y Paseo Tollocan s/n, Toluca (Mexico); Olguin, M.T. [Instituto Nacional de Investigaciones Nucleares, Departamento de Quimica, A.P. 18-1027, Col, Escandon, Del, Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico)], E-mail: mog@nuclear.inin.mx; Fall, Ch. [Centro Interamericano de Recursos del Agua, CIRA, km 14.5 de la Carretera Toluca - Ixtlahuaca, Unidad San Cayetano, Estado de Mexico (Mexico)

    2009-04-30

    Arsenate adsorption from aqueous solutions onto clinoptilolite-heulandite rich tuffs modified with iron or manganese or a mixture of both iron and manganese in this work was investigated. A kinetic model was considered to describe the arsenates adsorption on each zeolitic material. The modified clinoptilolite-heulandite rich tuffs were characterized by scanning electron microscopy and X-ray diffraction analysis. The elemental composition and the specific surface area of the zeolitic material were also determined. The arsenate adsorption by the modified zeolites was carried on in a batch system considering a contact time from 5 min to 24 h for the kinetic experimentation. The arsenic was detected by atomic absorption spectrometer using a hydride generator. The kinetics of the arsenate adsorption processes were described by the pseudo-second-order model and the obtained parameter k varies from 0.15 to 5.66 {mu}g/gh. In general, the results suggested that the kinetic adsorption of arsenates on the modified clinoptilolite-rich tuffs depend of the metallic specie that modified the surface characteristics of the zeolitic material, the chemical nature of the metal as well as the association between different metallic chemical species in the zeolitic surface.

  4. Speciation and Localization of Arsenic in White and Brown Rice Grains

    Meharg, Andrew A.; Lombi, Enzo; Williams, Paul N.; Scheckel, Kirk G.; Feldmann, Joerg; Raab, Andrea; Zhu, Yongguan; Islam, Rafiql (EPA); (Bangladesh); (UCopenhagen); (Aberdeen); (Chinese Aca. Sci.)

    2008-06-30

    Synchrotron-based X-ray fluorescence (S-XRF) was utilized to locate arsenic (As) in polished (white) and unpolished (brown) rice grains from the United States, China, and Bangladesh. In white rice As was generally dispersed throughout the grain, the bulk of which constitutes the endosperm. In brown rice As was found to be preferentially localized at the surface, in the region corresponding to the pericarp and aleurone layer. Copper, iron, manganese, and zinc localization followed that of arsenic in brown rice, while the location for cadmium and nickel was distinctly different, showing relatively even distribution throughout the endosperm. The localization of As in the outer grain of brown rice was confirmed by laser ablation ICP?MS. Arsenic speciation of all grains using spatially resolved X-ray absorption near edge structure (?-XANES) and bulk extraction followed by anion exchange HPLC?ICP?MS revealed the presence of mainly inorganic As and dimethylarsinic acid (DMA). However, the two techniques indicated different proportions of inorganic:organic As species. A wider survey of whole grain speciation of white (n = 39) and brown (n = 45) rice samples from numerous sources (field collected, supermarket survey, and pot trials) showed that brown rice had a higher proportion of inorganic arsenic present than white rice. Furthermore, the percentage of DMA present in the grain increased along with total grain arsenic.

  5. Arsenic pilot plant operation and results - Socorro Springs, New Mexico - phase 1.

    Aragon, Malynda Jo; Everett, Randy L.; Siegel, Malcolm Dean; Kottenstette, Richard Joseph; Holub, William E. Jr; Wright, Jeremy B.; Dwyer, Brian P.

    2007-05-01

    Sandia National Laboratories (SNL) is conducting pilot scale evaluations of the performance and cost of innovative water treatment technologies aimed at meeting the recently revised arsenic maximum contaminant level (MCL) for drinking water. The standard of 10 {micro}g/L (10 ppb) is effective as of January 2006. The first pilot tests have been conducted in New Mexico where over 90 sites that exceed the new MCL have been identified by the New Mexico Environment Department. The pilot test described in this report was conducted in Socorro New Mexico between January 2005 and July 2005. The pilot demonstration is a project of the Arsenic Water Technology Partnership program, a partnership between the American Water Works Association Research Foundation (AwwaRF), SNL and WERC (A Consortium for Environmental Education and Technology Development). The Sandia National Laboratories pilot demonstration at the Socorro Springs site obtained arsenic removal performance data for five different adsorptive media under constant ambient flow conditions. Well water at Socorro Springs has approximately 42 ppb arsenic in the oxidized (arsenate-As(V)) redox state with moderate amounts of silica, low concentrations of iron and manganese and a slightly alkaline pH (8). The study provides estimates of the capacity (bed volumes until breakthrough at 10 ppb arsenic) of adsorptive media in the same chlorinated water. Near the end of the test the feedwater pH was lowered to assess the affect on bed capacity and as a prelude to a controlled pH study (Socorro Springs Phase 2).

  6. 21 CFR 73.2775 - Manganese violet.

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Manganese violet. 73.2775 Section 73.2775 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2775 Manganese violet. (a) Identity. The color additive manganese violet is a violet pigment obtained by reacting phosphoric acid, ammonium...

  7. Manganese depresses rat heart muscle respiration

    It has previously been reported that moderately high dietary manganese (Mn) in combination with marginal magnesium (Mg) resulted in ultrastructural damage to heart mitochondria. Manganese may replace Mg in biological functions, including the role of enzyme cofactor. Manganese may accumulate and subs...

  8. 21 CFR 582.5449 - Manganese citrate.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Manganese citrate. 582.5449 Section 582.5449 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5449 Manganese citrate. (a) Product. Manganese citrate. (b) Conditions of use....

  9. 21 CFR 582.5461 - Manganese sulfate.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Manganese sulfate. 582.5461 Section 582.5461 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5461 Manganese sulfate. (a) Product. Manganese sulfate. (b) Conditions of use....

  10. 21 CFR 582.5455 - Manganese glycerophosphate.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Manganese glycerophosphate. 582.5455 Section 582.5455 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Dietary Supplements 1 § 582.5455 Manganese glycerophosphate. (a) Product. Manganese glycerophosphate....

  11. 21 CFR 582.5446 - Manganese chloride.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Manganese chloride. 582.5446 Section 582.5446 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5446 Manganese chloride. (a) Product. Manganese chloride. (b) Conditions of use....

  12. 21 CFR 582.5452 - Manganese gluconate.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Manganese gluconate. 582.5452 Section 582.5452 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5452 Manganese gluconate. (a) Product. Manganese gluconate. (b) Conditions of use....

  13. 21 CFR 582.5458 - Manganese hypophosphite.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Manganese hypophosphite. 582.5458 Section 582.5458 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5458 Manganese hypophosphite. (a) Product. Manganese hypophosphite. (b) Conditions of...

  14. A Phytoremediation Strategy for Arsenic

    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

  15. Arsenic Is A Genotoxic Carcinogen

    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...

  16. Arsenic concentrations in Chinese coals

    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

  17. Noncollinear magnetism in manganese nanostructures

    Zelený, Martin; Šob, Mojmír; Hafner, J.

    2009-01-01

    Roč. 80, č. 14 (2009), 144414/1-144414/19. ISSN 1098-0121 R&D Projects: GA AV ČR IAA100100920; GA MŠk OC09011 Institutional research plan: CEZ:AV0Z20410507 Keywords : magnetism of nanostructures * nanowires * noncollinear magnetism * manganese Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.475, year: 2009

  18. Arsenic in drinking-water and risk for cancer in Denmark

    Baastrup, Rikke; Sørensen, Mette; Balstrøm, Thomas;

    2008-01-01

    BACKGROUND: Arsenic is a well-known carcinogen, which is often found in drinking-water. Epidemiologic studies have shown increased cancer risks among individuals exposed to high concentrations of arsenic in drinking-water, whereas studies of the carcinogenic effect of low doses have had...... inconsistent results. OBJECTIVE: Our aim was to determine if exposure to low levels of arsenic in drinking-water in Denmark is associated with an increased risk for cancer. METHODS: The study was based on a prospective Danish cohort of 57,053 persons in the Copenhagen and Aarhus areas. Cancer cases were...... identified in the Danish Cancer Registry, and the Danish civil registration system was used to trace and geocode residential addresses of the cohort members. We used a geographic information system to link addresses with water supply areas, then estimated individual exposure to arsenic using residential...

  19. Address Points - Volusia County Addresses (Point)

    NSGIC GIS Inventory (aka Ramona) — Situs Addresses for Volusia County. Maintained by Growth and Resource Management. Addresses are determined by the cities for their jurisdiction and by the County...

  20. Spatial and seasonal changes of arsenic species in Lake Taihu in relation to eutrophication.

    Yan, Changzhou; Che, Feifei; Zeng, Liqing; Wang, Zaosheng; Du, Miaomiao; Wei, Qunshan; Wang, Zhenhong; Wang, Dapeng; Zhen, Zhuo

    2016-09-01

    Spatial and seasonal variations of arsenic species in Lake Taihu (including Zhushan Bay, Meiliang Bay, Gonghu Bay, and Southern Taihu) were investigated. Relatively high levels of total arsenic (TAs) and arsenate (As(V)) were observed in hyper-eutrophic regions during summer and autumn, which is attributed to exogenous contamination and seasonal endogenous release from sediments. The distributions of TAs and As(V) were significantly affected by total phosphorus, iron, manganese, and dissolved organic carbon. Arsenite (As(III)) and methylarsenicals (the sum of monomethylarsenic acid (MMA(V)) and dimethylarsenic acid (DMA(V))), mainly from biotransformation of As(V), were affected by temperature-controlled microalgae activities and local water quality parameters, exhibiting significantly higher concentrations and proportions in hyper-eutrophic and middle eutrophic regions during summer compared to mesotrophic region. The eutrophic environment, which induces changes in the main water quality parameters such as phosphorus, chlorophyll-a, iron, manganese, and dissolved organic carbon, can favor the biogeochemical cycling of arsenic in the aquatic systems. PMID:27152991

  1. Urinary Arsenic Metabolites of Subjects Exposed to Elevated Arsenic Present in Coal in Shaanxi Province, China

    Linsheng Yang; Jianwei Gao; Jiangping Yu

    2011-01-01

    In contrast to arsenic (As) poisoning caused by naturally occurring inorganic arsenic-contaminated water consumption, coal arsenic poisoning (CAP) induced by elevated arsenic exposure from coal combustion has rarely been reported. In this study, the concentrations and distributions of urinary arsenic metabolites in 57 volunteers (36 subjects with skin lesions and 21 subjects without skin lesions), who had been exposed to elevated levels of arsenic present in coal in Changshapu village in the ...

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

    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. -- Highlights: ► High soil arsenic and organic matter caused a reduction in plant growth. ► A delayed flowering time was observed in high arsenic and organic matter soil. ► Total grain arsenic increased in high arsenic and organic matter soil. ► Percentage organic arsenic in the grain altered in arsenic and organic matter soil. -- The addition of high amounts of organic matter to soils led to an increase in total rice grain arsenic, as well as alteration in the percentage arsenic species in the rice grains

  3. Arsenic in groundwater of Licking County, Ohio, 2012—Occurrence and relation to hydrogeology

    Thomas, Mary Ann

    2016-01-01

    Arsenic concentrations were measured in samples from 168 domestic wells in Licking County, Ohio, to document arsenic concentrations in a wide variety of wells and to identify hydrogeologic factors associated with arsenic concentrations in groundwater. Elevated concentrations of arsenic (greater than 10.0 micrograms per liter [µg/L]) were detected in 12 percent of the wells (about 1 in 8). The maximum arsenic concentration of about 44 µg/L was detected in two wells in the same township.A subset of 102 wells was also sampled for iron, sulfate, manganese, and nitrate, which were used to estimate redox conditions of the groundwater. Elevated arsenic concentrations were detected only in strongly reducing groundwater. Almost 20 percent of the samples with iron concentrations high enough to produce iron staining (greater than 300 µg/L) also had elevated concentrations of arsenic.In groundwater, arsenic primarily occurs as two inorganic species—arsenite and arsenate. Arsenic speciation was determined for a subset of nine samples, and arsenite was the predominant species. Of the two species, arsenite is more difficult to remove from water, and is generally considered to be more toxic to humans.Aquifer and well-construction characteristics were compiled from 99 well logs. Elevated concentrations of arsenic (and iron) were detected in glacial and bedrock aquifers but were more prevalent in glacial aquifers. The reason may be that the glacial deposits typically contain more organic carbon than the Paleozoic bedrock. Organic carbon plays a role in the redox reactions that cause arsenic (and iron) to be released from the aquifer matrix. Arsenic concentrations were not significantly different for different types of bedrock (sandstone, shale, sandstone/shale, or other). However, arsenic concentrations in bedrock wells were correlated with two well-construction characteristics; higher arsenic concentrations in bedrock wells were associated with (1) shorter open intervals and

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

    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

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

    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. Manganese Inhalation as a Parkinson Disease Model

    José Luis Ordoñez-Librado; Verónica Anaya-Martínez; Ana Luisa Gutierrez-Valdez; Laura Colín-Barenque; Enrique Montiel-Flores; Maria Rosa Avila-Costa

    2011-01-01

    The present study examines the effects of divalent and trivalent Manganese (Mn2+/Mn3+) mixture inhalation on mice to obtain a novel animal model of Parkinson disease (PD) inducing bilateral and progressive dopaminergic cell death, correlate those alterations with motor disturbances, and determine whether L-DOPA treatment improves the behavior, to ensure that the alterations are of dopaminergic origin. CD-1 male mice inhaled a mixture of Manganese chloride and Manganese acetate, one hour twice...

  7. Manganese in long term paediatric parenteral nutrition.

    Reynolds, A. P.; Kiely, E; Meadows, N

    1994-01-01

    The current practice of providing manganese supplementation to neonates on long term parenteral nutrition is leading to a high incidence of hypermanganesaemia. Magnetic resonance imaging (MRI) studies in adults on long term manganese parenteral nutrition have shown changes in TI weighted MRI images and similar findings in a neonate receiving trace element supplementation are reported here. Whole blood manganese concentration in the infant was 1740 nmol/l (or 8.3 times upper reference limit). ...

  8. Discovery of the Arsenic Isotopes

    SHORE, A.; A. Fritsch; Heim, M.; Schuh, A.; Thoennessen, M

    2009-01-01

    Twenty-nine arsenic isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

  9. Assessment of Arsenic Contamination of Groundwater and Health Problems in Bangladesh

    Amal K. Mitra

    2005-08-01

    Full Text Available Excessive amounts of arsenic (As in the groundwater in Bangladesh and neighboring states in India are a major public health problem. About 30% of the private wells in Bangladesh exhibit high concentrations of arsenic. Over half the country, 269 out of 464 administrative units, is affected. Similar problems exist in many other parts of the world, including the Unites States. This paper presents an assessment of the health hazards caused by arsenic contamination in the drinking water in Bangladesh. Four competing hypotheses, each addressing the sources, reaction mechanisms, pathways, and sinks of arsenic in groundwater, were analyzed in the context of the geologic history and land-use practices in the Bengal Basin. None of the hypotheses alone can explain the observed variability in arsenic concentration in time and space; each appears to have some validity on a local scale. Thus, it is likely that several bio-geochemical processes are active among the region’s various geologic environments, and that each contributes to the mobilization and release of arsenic. Additional research efforts will be needed to understand the relationships between underlying biogeochemical factors and the mechanisms for arsenic release in various geologic settings.

  10. Allegheny County Address Points

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset contains address points which represent physical address locations assigned by the Allegheny County addressing authority. Data is updated by County...

  11. Estimated probability of arsenic in groundwater from bedrock aquifers in New Hampshire, 2011

    Ayotte, Joseph D.; Cahillane, Matthew; Hayes, Laura; Robinson, Keith W.

    2012-01-01

    wells, and in ecological-level analysis of disease outcomes. The approach for modeling arsenic in groundwater could also be applied to other environmental contaminants that have potential implications for human health, such as uranium, radon, fluoride, manganese, volatile organic compounds, nitrate, and bacteria.

  12. Evaluation of radiochemical neutron activation analysis methods for determination of arsenic in biological materials.

    Paul, Rick L

    2011-01-01

    Radiochemical neutron activation analysis (RNAA) with retention on hydrated manganese dioxide (HMD) has played a key role in the certification of As in biological materials at NIST. Although this method provides very high and reproducible yields and detection limits at low microgram/kilogram levels, counting geometry uncertainties may arise from unequal distribution of As in the HMD, and arsenic detection limits may not be optimal due to significant retention of other elements. An alternate RNAA procedure with separation of arsenic by solvent extraction has been investigated. After digestion of samples in nitric and perchloric acids, As(III) is extracted from 2 M sulfuric acid solution into a solution of zinc diethyldithiocarbamate in chloroform. Counting of (76)As allows quantitation of arsenic. Addition of an (77)As tracer solution prior to dissolution allows correction for chemical yield and counting geometries, further improving reproducibility. The HMD and solvent extraction procedures for arsenic were compared through analysis of SRMs 1577c (bovine liver), 1547 (peach leaves), and 1575a (pine needles). Both methods gave As results in agreement with certified values with comparable reproducibility. However, the solvent extraction method yields a factor of 3 improvement in detection limits and is less time-consuming than the HMD method. The new method shows great promise for use in As certification in reference materials. PMID:21133431

  13. Response of the microbial metallome to arsenic stress

    Wolfe-Simon, F.; Lancaster, W. A.; Menon, A. L.; Yannone, S. M.; Adams, M. W.; Tainer, J. A.

    2012-12-01

    Life depends on access to nutrients in the environment. While elements such as nitrogen, carbon, sulfur and phosphorus are fundamental to microbial survival, trace nutrient elements like iron, molybdenum and copper show dramatically different profiles depending on environmental conditions. These elements are known nutrients but also can be toxic at higher concentrations. For low or limiting concentrations of one nutrient element, microbes may utilize another element to serve similar functions often, but not always, in similar macromolecular structures. Well-characterized elemental exchanges include manganese for iron and tungsten for molybdenum. Here we report on our preliminary metallomic analyses of the Gammaproteobacterium Halomonas sp. str. GFAJ-1 grown under severe arsenic stress. We analyzed 53 elements by ICP-MS, in order to determine which elements are tightly, weakly or not bound to soluble macromolecules (> 3 kDa). We specifically investigated the changes to the metallome of GFAJ-1cells that were grown in the synthetic minimal medium AML60 supplemented with 50 mM arsenate (As(V)), 50 μM phosphate (P) or 50 mM As(V) plus 50 μM P. Further studies will identify which macromolecules are associated with the various elements. This research extends our understanding of metal assimilation in microbes in response to tandem phosphorus limitation coupled to extreme arsenic concentrations and furthermore contributes to the expanding set of chemical elements utilized by microbes in unusual environmental niches.

  14. Battles with Iron: Manganese in Oxidative Stress Protection*

    Aguirre, J. Dafhne; Culotta, Valeria C.

    2012-01-01

    The redox-active metal manganese plays a key role in cellular adaptation to oxidative stress. As a cofactor for manganese superoxide dismutase or through formation of non-proteinaceous manganese antioxidants, this metal can combat oxidative damage without deleterious side effects of Fenton chemistry. In either case, the antioxidant properties of manganese are vulnerable to iron. Cellular pools of iron can outcompete manganese for binding to manganese superoxide dismutase, and through Fenton c...

  15. Manganese mineralogy and diagenesis in the sedimentary rock record

    Johnson, Jena E.; Webb, Samuel M.; Ma, Chi; Fischer, Woodward W.

    2016-01-01

    Oxidation of manganese(II) to manganese(III,IV) demands oxidants with very high redox potentials; consequently, manganese oxides are both excellent proxies for molecular oxygen and highly favorable electron acceptors when oxygen is absent. The first of these features results in manganese-enriched sedimentary rocks (manganese deposits, commonly Mn ore deposits), which generally correspond to the availability of molecular oxygen in Earth surface environments. And yet because manganese reduction...

  16. Arsenic removal by lime softening

    Kaosol, T.; Suksaroj, C.; Bregnhøj, Henrik

    This paper focuses on the study of arsenic removal for drinking water by lime softening. The initial arsenic (V) concentration was 500 and 1,000 ug/L in synthetic groundwater. The experiments were performed as batch tests with varying lime dosages and mixing time. For the synthetic groundwater......, arsenic (V) removal increased with increasing lime dosage and mixing time, as well as with the resulting pH. The residual arsenic (V) in all cases was lower than the WHO guideline of 10 ug/L at pH higher than 11.5. Kinetic of arsenic (V) removal can be described by a first-order equation as C1 = C0*e......^-k*t. The relation between the constant (k value) and increasing lime dosage was found to be linear, described by k = 0.0034 (Dlime). The results support a theory from the literature that the arsenic (V) was removed by precipitation af Ca3(AsO4)2. The results obtained in the present study suggest that lime...

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

    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 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

  18. Arsenic Toxicity in Male Reproduction and Development.

    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

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

    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…

  20. Arsenic speciation and bioaccessibility in arsenic-contaminated soils: Sequential extraction and mineralogical investigation

    In this study, a combination of sequential extraction and mineralogical investigation by X-ray diffraction and X-ray photoelectron spectroscopy was employed in order to evaluate arsenic solid-state speciation and bioaccessibility in soils highly contaminated with arsenic from mining and smelting. Combination of these techniques indicated that iron oxides and the weathering products of sulfide minerals played an important role in regulating the arsenic retention in the soils. Higher bioaccessibility of arsenic was observed in the following order; i) arsenic bound to amorphous iron oxides (smelter-2), ii) arsenic associated with crystalline iron oxides and arsenic sulfide phase (smelter-1), and iii) arsenic associated with the weathering products of arsenic sulfide minerals, such as scorodite, orpiment, jarosite, and pyrite (mine). Even though the bioaccessibility of arsenic was very low in the mine soil, its environmental impact could be significant due to its high arsenic concentration and mobility. Highlights: • Combination of sequential extraction and mineralogical investigation was employed. • Arsenic was primarily associated with iron oxides and sulfide minerals in soils. • Bioaccessibility of arsenic was affected by arsenic solid-phase speciation. -- We investigated arsenic solid-state speciation in soils, which is crucial for risk assessment and developing suitable remediation strategies in arsenic contaminated sites

  1. About the presence of arsenic in prebiotic species

    Ellinger Y.; Toulouze M.; Pilmé J.; Pauzat F.

    2014-01-01

    The recent publication that some bacteria could use arsenic instead of phosphorus for building their DNA triggered a large controversy in the astro/exobiology community. Most comments claim that such a substitution is not possible. Here, we address the same question of the presence of As in DNA from a pure theoretical point of view, beyond any biological consideration. By means of “First principle“ quantum calculations we found that there is no energetical or structural argument to reject the...

  2. Analytical approaches for arsenic determination in air: A critical review.

    Sánchez-Rodas, Daniel; de la Campa, Ana M Sánchez; Alsioufi, Louay

    2015-10-22

    This review describes the different steps involved in the determination of arsenic in air, considering the particulate matter (PM) and the gaseous phase. The review focuses on sampling, sample preparation and instrumental analytical techniques for both total arsenic determination and speciation analysis. The origin, concentration and legislation concerning arsenic in ambient air are also considered. The review intends to describe the procedures for sample collection of total suspended particles (TSP) or particles with a certain diameter expressed in microns (e.g. PM10 and PM2.5), or the collection of the gaseous phase containing gaseous arsenic species. Sample digestion of the collecting media for PM is described, indicating proposed and established procedures that use acids or mixtures of acids aided with different heating procedures. The detection techniques are summarized and compared (ICP-MS, ICP-OES and ET-AAS), as well those techniques capable of direct analysis of the solid sample (PIXE, INAA and XRF). The studies about speciation in PM are also discussed, considering the initial works that employed a cold trap in combination with atomic spectroscopy detectors, or the more recent studies based on chromatography (GC or HPLC) combined with atomic or mass detectors (AFS, ICP-MS and MS). Further trends and challenges about determination of As in air are also addressed. PMID:26526905

  3. Arsenic Mobility and Availability in Sediments by Application of BCR Sequential Extractions Method; Movilidad y Disponibilidad de Arsenico en Sedimentos Mediante la Aplicacion del Metodo de Extracciones Secuenciales BCR

    Larios, R.; Fernandez, R.; Rucandio, M. I.

    2011-05-13

    Arsenic is a metalloid found in nature, both naturally and due to anthropogenic activities. Among them, mining works are an important source of arsenic release to the environment. Asturias is a region where important mercury mines were exploited, and in them arsenic occurs in para genesis with mercury minerals. The toxicity and mobility of this element depends on the chemical species it is found. Fractionation studies are required to analyze the mobility of this metalloid in soils and sediments. Among them, the proposed by the Bureau Community of Reference (BCR) is one of the most employed. This method attempts to divide up, by operationally defined stages, the amount of this element associated with carbonates (fraction 1), iron and manganese oxy hydroxides (fraction 2), organic matter and sulphides (fraction 3), and finally as the amount associated residual fraction to primary and secondary minerals, that is, from the most labile fractions to the most refractory ones. Fractionation of arsenic in sediments from two mines in Asturias were studied, La Soterrana and Los Rueldos. Sediments from La Soterrana showed high levels of arsenic in the non-residual phases, indicating that the majority of arsenic has an anthropogenic origin. By contrast, in sediments from Los Rueldos most of the arsenic is concentrated in the residual phase, indicating that this element remains bound to very refractory primary minerals, as is also demonstrated by the strong correlation of arsenic fractionation and the fractionation of elements present in refractory minerals, such as iron, aluminum and titanium. (Author) 51 refs.

  4. Potential of Using ROSA Centifolia to Remove Iron and Manganese in Groundwater Treatment

    Aslina Abdul Kadir

    2012-11-01

    Full Text Available Groundwater is source for water supply because of its good natural quality. However, groundwater may be exposed toward to contamination by various anthropogenic activities such as agricultural, domestic and industrial. Groundwater quality problem are typically associated with high hardness, high salinity and elevated concentration of iron, manganese, ammonium, fluoride and occasionally nitrate and arsenic.  Therefore, groundwater should be treated to acceptable level before consumption. This study is carried out with the objectives to optimize the feasibility condition of contact time, biosorbent dosage and pH range in removing heavy metal by using Rosa Centifolia (R. Centifolia and also to determine the water quality of groundwater sources.  A dried Rosa Centifolia pretreated before being used as biosorbent. Experiment was done by varying contact time, biosorbent dosage and pH range to get the optimum value. The removal characteristic of Iron and Manganese by Rosa Centifolia was analyzed using Atomic Absorption Spectrophotometer (AAS. The optimum condition is achieved at 240minutes, 0.05g/ml and pH 5 respectively. The optimum percentage removal of Iron and Manganese was found to be more than 70%. The finding indicated that Rosa Centifolia is a promising biosorbent in treating groundwater from RECESS UTHM well.

  5. Large Magnetic Moments of Arsenic-Doped Mn Clusters and their Relevance to Mn-Doped III-V Semiconductor Ferromagnetism

    Kabir, M; Mookerjee, A; Kabir, Mukul; Mookerjee, Abhijit

    2005-01-01

    We report electronic and magnetic structure of arsenic-doped manganese clusters from density-functional theory using generalized gradient approximation for the exchange-correlation energy. We find that arsenic stabilizes manganese clusters, though the ferromagnetic coupling between Mn atoms are found only in Mn$_2$As and Mn$_4$As clusters with magnetic moments 9 $\\mu_B$ and 17 $\\mu_B$, respectively. For all other sizes, $x=$ 3, 5-10, Mn$_x$As clusters show ferrimagnetic coupling. It is suggested that, if grown during the low temperature MBE, the giant magnetic moments due to ferromagnetic coupling in Mn$_2$As and Mn$_4$As clusters could play a role on the ferromagnetism and on the variation observed in the Curie temperature of Mn-doped III-V semiconductors.

  6. Arsenic speciation in saliva of acute promyelocytic leukemia patients undergoing arsenic trioxide treatment

    Chen, Baowei; Cao, Fenglin; Yuan, Chungang; Lu, Xiufen; Shen, Shengwen; Zhou, Jin; Le, X Chris

    2013-01-01

    Arsenic trioxide has been successfully used as a therapeutic in the treatment of acute promyelocytic leukemia (APL). Detailed monitoring of the therapeutic arsenic and its metabolites in various accessible specimens of APL patients can contribute to improving treatment efficacy and minimizing arsenic-induced side effects. This article focuses on the determination of arsenic species in saliva samples from APL patients undergoing arsenic treatment. Saliva samples were collected from nine APL pa...

  7. Arsenic in contaminated soil and river sediment

    Different areas in the Erzgebirge mountains are contaminated by high arsenic concentration which is caused by the occurrence of ore and industrial sources. The study showed clearly a high concentration of arsenic in the surface and under soil (A and B horizons) in the Freiberg district. The distribution of the arsenic concentration in the area, the content of water soluble arsenic, the several oxidation states (As3+, As5+) and the bonding types have been analyzed. (orig.)

  8. Arsenic Exposure and Toxicology: A Historical Perspective

    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 o...

  9. Arsenic in contaminated soil and river sediment

    Bombach, G. (Freiberg Univ. of Mining and Technology, Inst. of Mineralogy, Geochemistry and Ore Deposits, Freiberg (Germany)); Pierra, A. (Freiberg Univ. of Mining and Technology, Inst. of Mineralogy, Geochemistry and Ore Deposits, Freiberg (Germany)); Klemm, W. (Freiberg Univ. of Mining and Technology, Inst. of Mineralogy, Geochemistry and Ore Deposits, Freiberg (Germany))

    1994-09-01

    Different areas in the Erzgebirge mountains are contaminated by high arsenic concentration which is caused by the occurrence of ore and industrial sources. The study showed clearly a high concentration of arsenic in the surface and under soil (A and B horizons) in the Freiberg district. The distribution of the arsenic concentration in the area, the content of water soluble arsenic, the several oxidation states (As[sup 3+], As[sup 5+]) and the bonding types have been analyzed. (orig.)

  10. 21 CFR 556.60 - Arsenic.

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Arsenic. 556.60 Section 556.60 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND... New Animal Drugs § 556.60 Arsenic. Tolerances for total residues of combined arsenic (calculated as...

  11. Chloride sublimation of gold-arsenic concentrates

    Present article is devoted to chloride sublimation of gold-arsenic concentrates. The results of studies of chloride sublimation of gold-arsenic comprising concentrates of Chore deposit of Tajikistan are considered. It is found that by application sodium chloride for gold-arsenic comprising concentrates it is possible to extract gold and silver from flotation concentrates.

  12. Arsenic removal from industrial effluent through electrocoagulation

    Balasubramanian, N. [Central Electrochemical Research Inst., Karaikudi (India). Dept. of Pollution Control; Madhavan, K. [Coimbatore Inst. of Technology, Coimbatore (India). Dept. of Chemistry

    2001-05-01

    In the present investigation, it is attempted to remove arsenic from smelter industrial wastewater through electro-coagulation. Experiments covering a wide range of operating conditions for removal of the arsenic present in the smelter wastewater are carried out in a batch electrochemical reactor. It has been observed from the present work that arsenic can be removed effectively through electrocoagulation. (orig.)

  13. Preparation of Manganese Oxide Nanobelts

    Jisen WANG; Jinquan SUN; Ying BAO; Xiufang BIAN

    2003-01-01

    Oriented nanobelts of manganese oxide have been firstly and successfully prepared by a microemulsion techniqueunder controlled circumstances. The samples were characterized by X-ray diffraction (XRD), transmission electronmicroscope (TEM). Influences of sodium chloride and annealed temperature on the synthesis of Mn3O4 nanobeltswere investigated. It was found that NaCl is the key factor to synthesize oriented Mn3O4 nanobelts and 827 K isoptimum temperature to produce fine nanobelts. Oriented growth mechanism of Mn3O4 nanobelts was discussed.

  14. Arsenic – Poison or medicine?

    Karolina Kulik-Kupka

    2016-04-01

    Full Text Available Arsenic (As is commonly known as a poison. Only a few people know that As has also been widely used in medicine. In the past years As and its compounds were used as a medicine for the treatment of such diseases as diabetes, psoriasis, syphilis, skin ulcers and joint diseases. Nowadays As is also used especially in the treatment of patients with acute promyelocytic leukemia. The International Agency for Research on Cancer (IARC has recognized arsenic as an element with carcinogenic effect evidenced by epidemiological studies, but as previously mentioned it is also used in the treatment of neoplastic diseases. This underlines the specificity of the arsenic effects. Arsenic occurs widely in the natural environment, for example, it is present in soil and water, which contributes to its migration to food products. Long exposure to this element may lead to liver damages and also to changes in myocardium. Bearing in mind that such serious health problems can occur, monitoring of the As presence in the environmental media plays a very important role. In addition, the occupational risk of As exposure in the workplace should be identified and checked. Also the standards for As presence in food should be established. This paper presents a review of the 2015 publications based on the Medical database like PubMed and Polish Medical Bibliography. It includes the most important information about arsenic in both forms, poison and medicine. Med Pr 2016;67(1:89–96

  15. Reach Address Database (RAD)

    U.S. Environmental Protection Agency — The Reach Address Database (RAD) stores the reach address of each Water Program feature that has been linked to the underlying surface water features (streams,...

  16. Whole-house arsenic water treatment provided more effective arsenic exposure reduction than point-of-use water treatment at New Jersey homes with arsenic in well water

    Spayd, Steven E.; Robson, Mark G.; Buckley, Brian T.

    2014-01-01

    A comparison of the effectiveness of whole house (point-of-entry) and point-of-use arsenic water treatment systems in reducing arsenic exposure from well water was conducted. The non-randomized observational study recruited 49 subjects having elevated arsenic in their residential home well water in New Jersey. The subjects obtained either point-of-entry or point-of-use arsenic water treatment. Prior ingestion exposure to arsenic in well water was calculated by measuring arsenic concentrations...

  17. Arsenic mobility in contaminated lake sediments

    An arsenic contaminated lake sediment near a landfill in Maine was used to characterize the geochemistry of arsenic and assess the influence of environmental conditions on its mobility. A kinetic model was developed to simulate the leaching ability of arsenic in lake sediments under different environmental conditions. The HM1D chemical transport model was used to model the column experiments and determine the rates of arsenic mobility from the sediment. Laboratory studies provided the information to construct a conceptual model to demonstrate the mobility of arsenic in the lake sediment. The leaching ability of arsenic in lake sediments greatly depends on the flow conditions of ground water and the geochemistry of the sediments. Large amounts of arsenic were tightly bound to the sediments. The amount of arsenic leaching out of the sediment to the water column was substantially decreased due to iron/arsenic co-precipitation at the water-sediment interface. Overall, it was found that arsenic greatly accumulated at the ground water/lake interface and it formed insoluble precipitates. - Arsenic accumulates at the ground water/lake interface, where it forms insoluble precipitates

  18. Neutron activation analysis of arsenic in Greece

    Arsenic is considered a toxic trace element for plant, animal, and human organisms. Arsenic and certain arsenic compounds have been listed as carcinogens by the U.S. Environmental Protection Agency. Arsenic is emitted in appreciable quantities into the atmosphere by coal combustion and the production of cement. Arsenic enters the aquatic environment through industrial activities such as smelting of metallic ores, metallurgical glassware, and ceramics as well as insecticide production and use. Neutron activation analysis (NAA) is a very sensitive, precise, and accurate method for determining arsenic. This paper is a review of research studies of arsenic in the Greek environment by NAA performed at our radioanalytical laboratory. The objectives of these studies were (a) to determine levels of arsenic concentrations in environmental materials, (b) to pinpoint arsenic pollution sources and estimate the extent of arsenic pollution, and (c) to find out whether edible marine organisms from the gulfs of Greece receiving domestic, industrial, and agricultural wastes have elevated concentrations of arsenic in their tissues that could render them dangerous for human consumption

  19. Removal processes for arsenic in constructed wetlands.

    Lizama A, Katherine; Fletcher, Tim D; Sun, Guangzhi

    2011-08-01

    Arsenic pollution in aquatic environments is a worldwide concern due to its toxicity and chronic effects on human health. This concern has generated increasing interest in the use of different treatment technologies to remove arsenic from contaminated water. Constructed wetlands are a cost-effective natural system successfully used for removing various pollutants, and they have shown capability for removing arsenic. This paper reviews current understanding of the removal processes for arsenic, discusses implications for treatment wetlands, and identifies critical knowledge gaps and areas worthy of future research. The reactivity of arsenic means that different arsenic species may be found in wetlands, influenced by vegetation, supporting medium and microorganisms. Despite the fact that sorption, precipitation and coprecipitation are the principal processes responsible for the removal of arsenic, bacteria can mediate these processes and can play a significant role under favourable environmental conditions. The most important factors affecting the speciation of arsenic are pH, alkalinity, temperature, dissolved oxygen, the presence of other chemical species--iron, sulphur, phosphate--,a source of carbon, and the wetland substrate. Studies of the microbial communities and the speciation of arsenic in the solid phase using advanced techniques could provide further insights on the removal of arsenic. Limited data and understanding of the interaction of the different processes involved in the removal of arsenic explain the rudimentary guidelines available for the design of wetlands systems. PMID:21549410

  20. Deposition of manganese in a drinking water distribution system.

    Sly, L I; M.C. Hodgkinson; Arunpairojana, V

    1990-01-01

    The deposition of manganese in a water distribution system with manganese-related "dirty water" problems was studied over a 1-year period. Four monitoring laboratories with Robbins biofilm sampling devices fitted to the water mains were used to correlate the relationship among manganese deposition, the level of manganese in the water, and the chlorination conditions. Manganese deposition occurred by both chemical and microbial processes. Chemical deposition occurred when Mn(II) not removed du...

  1. EFFECTS OF MANGANESE ON THYROID HORMONE HOMEOSTASIS: POTENTIAL LINKS

    Soldin, OP; Aschner, M.

    2007-01-01

    Manganese (Mn) is an essential trace nutrient that is potentially toxic at high levels of exposure. As a constituent of numerous enzymes and a cofactor, manganese plays an important role in a number of physiologic processes in mammals. The manganese-containing enzyme, manganese superoxide dismutase (Mn-SOD), is the principal antioxidant enzyme which neutralizes the toxic effects of reactive oxygen species. Other manganese-containing enzymes include oxidoreductases, transferases, hydrolases, l...

  2. Manganese transport in Brevibacterium ammoniagenes ATCC 6872.

    Schmid, J.; Auling, G

    1987-01-01

    Uptake of manganese by Brevibacterium ammoniagenes ATCC 6872 was energy dependent and obeyed saturation kinetics (Km = 0.65 microM; Vmax = 0.12 mumol/min per g [dry weight]). Uptake showed optima at 27 degrees C and pH 9.5. 54Mn2+ accumulated by the cells was released by treatment with toluene or by exchange for unlabeled manganese ions, via an energy-dependent process. Co2+, Fe2+, Cd2+, and Zn2+ inhibited manganese uptake. Inhibition by Cd2+ and Zn2+ was competitive (Ki = 0.15 microM Cd2+ an...

  3. Effects of plant arsenic uptake and heavy metals on arsenic distribution in an arsenic-contaminated soil

    Fayiga, Abioye O. [Soil and Water Science Department, University of Florida, Gainesville, FL 32611-0290 (United States); Ma, Lena Q. [Soil and Water Science Department, University of Florida, Gainesville, FL 32611-0290 (United States) and Key Laboratory of Terrestrial Ecological Process, Chinese Academy of Sciences, Shenyang 110016 (China)]. E-mail: lqma@ifas.ufl.edu; Zhou Qixing [Key Laboratory of Terrestrial Ecological Process, Chinese Academy of Sciences, Shenyang 110016 (China)

    2007-06-15

    This study examined the effects of heavy metals and plant arsenic uptake on soil arsenic distribution. Chemical fractionation of an arsenic-contaminated soil spiked with 50 or 200 mg kg{sup -1} Ni, Zn, Cd or Pb was performed before and after growing the arsenic hyperaccumulator Pteris vittata L for 8 weeks using NH{sub 4}Cl (water-soluble plus exchangeable, WE-As), NH{sub 4}F (Al-As), NaOH (Fe-As), and H{sub 2}SO{sub 4} (Ca-As). Arsenic in the soil was present primarily as the recalcitrant forms with Ca-As being the dominant fraction (45%). Arsenic taken up by P. vittata was from all fractions though Ca-As contributed the most (51-71% reduction). After 8 weeks of plant growth, the Al-As and Fe-As fractions were significantly (p < 0.01) greater in the metal-spiked soils than the control, with changes in the WE-As fraction being significantly (p = 0.007) correlated with plant arsenic removal. The plant's ability to solubilize soil arsenic from recalcitrant fractions may have enhanced its ability to hyperaccumulate arsenic. - Arsenic taken up by P. vittata was from all fractions with most from the Ca-fraction.

  4. Urinary Arsenic Metabolites of Subjects Exposed to Elevated Arsenic Present in Coal in Shaanxi Province, China

    Linsheng Yang

    2011-06-01

    Full Text Available In contrast to arsenic (As poisoning caused by naturally occurring inorganic arsenic-contaminated water consumption, coal arsenic poisoning (CAP induced by elevated arsenic exposure from coal combustion has rarely been reported. In this study, the concentrations and distributions of urinary arsenic metabolites in 57 volunteers (36 subjects with skin lesions and 21 subjects without skin lesions, who had been exposed to elevated levels of arsenic present in coal in Changshapu village in the south of Shaanxi Province (China, were reported. The urinary arsenic species, including inorganic arsenic (iAs [arsenite (iAsIII and arsenate (iAsV], monomethylarsonic acid (MMAV and dimethylarsinic acid (DMAV, were determined by high-performance liquid chromatography (HPLC combined with inductively coupled plasma mass spectroscopy (ICP-MS. The relative distributions of arsenic species, the primary methylation index (PMI = MMAV/iAs and the secondary methylation index (SMI = DMAV/MMAV were calculated to assess the metabolism of arsenic. Subjects with skin lesions had a higher concentration of urinary arsenic and a lower arsenic methylation capability than subjects without skin lesions. Women had a significantly higher methylation capability of arsenic than men, as defined by a higher percent DMAV and SMI in urine among women, which was the one possible interpretation of women with a higher concentration of urinary arsenic but lower susceptibility to skin lesions. The findings suggested that not only the dose of arsenic exposure but also the arsenic methylation capability have an impact on the individual susceptibility to skin lesions induced by coal arsenic exposure.

  5. Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

    Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W.; Loy, Alexander; Thamdrup, Bo

    2012-01-01

    Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the p...

  6. Manganese concentrate usage in steelmaking

    Nokhrina, O. I.; Rozhihina, I. D.

    2015-09-01

    The results of the research process of producing metalized products by solid-phase reduction of iron using solid carbonaceous reducing agents. Thermodynamic modeling was carried out on the model of the unit the Fe-C-O and system with iron ore and coal. As a result of modeling the thermodynamic boundary reducing, oxidizing, and transition areas and the value of the ratio of carbon and oxygen in the system. Simulation of real systems carried out with the gas phase obtained in the pyrolys of coal. The simulation results allow to determine the optimal cost of coal required for complete reduction of iron ore from a given composition. The kinetics of the processes of solid-phase reduction of iron using coal of various technological brands. The paper describes experiments on effects of metal deoxidizer composition, component proportion, pelletizing mixture, particle size distribution of basic materials and flux on manganese recovering from oxides under direct melting.

  7. Manganese-based Permanent Magnets

    Ian Baker

    2015-08-01

    Full Text Available There is a significant gap between the energy product, BH, where B is the magnetic flux density and H is the magnetic field strength, of both the traditional ferrite and AlNiCo permanent magnets of less than 10 MGOe and that of the rare earth magnets of greater than 30 MGOe. This is a gap that Mn-based magnets could potentially, inexpensively, fill. This Special Issue presents work on the development of both types of manganese permanent magnets. Some of the challenges involved in the development of these magnets include improving the compounds’ energy product, increasing the thermal stability of these metastable compounds, and producing them in quantity as a bulk material.[...

  8. Bimetallic nanoparticles for arsenic detection.

    Moghimi, Nafiseh; Mohapatra, Mamata; Leung, Kam Tong

    2015-06-01

    Effective and sensitive monitoring of heavy metal ions, particularly arsenic, in drinking water is very important to risk management of public health. Arsenic is one of the most serious natural pollutants in soil and water in more than 70 countries in the world. The need for very sensitive sensors to detect ultralow amounts of arsenic has attracted great research interest. Here, bimetallic FePt, FeAu, FePd, and AuPt nanoparticles (NPs) are electrochemically deposited on the Si(100) substrate, and their electrochemical properties are studied for As(III) detection. We show that trace amounts of As(III) in neutral pH could be determined by using anodic stripping voltammetry. The synergistic effect of alloying with Fe leads to better performance for Fe-noble metal NPs (Au, Pt, and Pd) than pristine noble metal NPs (without Fe alloying). Limit of detection and linear range are obtained for FePt, FeAu, and FePd NPs. The best performance is found for FePt NPs with a limit of detection of 0.8 ppb and a sensitivity of 0.42 μA ppb(-1). The selectivity of the sensor has also been tested in the presence of a large amount of Cu(II), as the most detrimental interferer ion for As detection. The bimetallic NPs therefore promise to be an effective, high-performance electrochemical sensor for the detection of ultratrace quantities of arsenic. PMID:25938763

  9. Determination of arsenic compounds in earthworms

    Geiszinger, A.; Goessler, W.; Kuehnelt, D.; Kosmus, W. [Karl-Franzens-Univ., Graz (Austria). Inst. for Analytical Chemistry; Francesconi, K. [Odense Univ. (Denmark). Inst. of Biology

    1998-08-01

    Earthworms and soil collected from six sites in Styria, Austria, were investigated for total arsenic concentrations by ICP-MS and for arsenic compounds by HPLC-ICP-MS. Total arsenic concentrations ranged from 3.2 to 17.9 mg/kg dry weight in the worms and from 5.0 to 79.7 mg/kg dry weight in the soil samples. There was no strict correlation between the total arsenic concentrations in the worms and soil. Arsenic compounds were extracted from soil and a freeze-dried earthworm sample with a methanol/water mixture (9:1, v/v). The extracts were evaporated to dryness, redissolved in water, and chromatographed on an anion- and a cation-exchange column. Arsenic compounds were identified by comparison of the retention times with known standards. Only traces of arsenic acid could be extracted from the soil with the methanol/water (9:1, v/v) mixture. The major arsenic compounds detected in the extracts of the earthworms were arsenous acid and arsenic acid. Arsenobetaine was present as a minor constituent, and traces of dimethylarsinic acid were also detected. Two dimethylarsinoyltribosides were also identified in the extracts by co-chromatography with standard compounds. This is the first report of the presence of dimethylarsinoylribosides in a terrestrial organism. Two other minor arsenic species were present in the extract, but their retention times did not match with the retention times of the available standards.

  10. Variability in human metabolism of arsenic

    Estimating the nature and extent of human cancer risks due to arsenic (As) in drinking water is currently of great concern, since millions of persons worldwide are exposed to arsenic, primarily through natural enrichment of drinking water drawn from deep wells. Humans metabolize and eliminate As through oxidative methylation and subsequent urinary excretion. While there is debate as to the role of methylation in activation/detoxification, variations in arsenic metabolism may affect individual risks of toxicity and carcinogenesis. Using data from three populations, from Mexico, China, and Chile, we have analyzed the distribution in urine of total arsenic and arsenic species (inorganic arsenic (InAs), monomethyl arsenic (MMA), and dimethyl arsenic (DMA). Data were analyzed in terms of the concentration of each species and by evaluating MMA:DMA and (MMA+DMA):InAs ratios. In all persons most urinary As was present as DMA. Male:female differences were discernible in both high- and low-exposure groups from all three populations, but the gender differences varied by populations. The data also indicated bimodal distributions in the ratios of DMA to InAs and to MMA. While the gene or genes responsible for arsenic methylation are still unknown, the results of our studies among the ethnic groups in this study are consistent with the presence of functional genetic polymorphisms in arsenic methylation leading to measurable differences in toxicity. This analysis highlights the need for continuing research on the health effects of As in humans using molecular epidemiologic methods

  11. Synthesis and Characterization of Manganese Carboxylates

    Maryudi; R.M. Yunus; A.H. Nour; M.H. Abidin

    2009-01-01

    The explorations of prodegradant additives for plastics from trans-metals organic salts have been being conducted. This study reports a method of synthesis of manganese carboxylates and their characterization. The new method involves reaction between molten carboxylic acid with sodium hydroxide in alcoholic solution to produce sodium carboxylate and continued by reacting sodium carboxylate with chloride salt of manganese. First reaction and second reaction were conducted at 80-85°C and under ...

  12. Breast-feeding Protects against Arsenic Exposure in Bangladeshi Infants

    Fängström, Britta; Moore, Sophie; Nermell, Barbro; Kuenstl, Linda; Goessler, Walter; Grandér, Margaretha; Kabir, Iqbal; Palm, Brita; Arifeen, Shams El; Vahter, Marie

    2008-01-01

    Background Chronic arsenic exposure causes a wide range of health effects, but little is known about critical windows of exposure. Arsenic readily crosses the placenta, but the few available data on postnatal exposure to arsenic via breast milk are not conclusive. Aim Our goal was to assess the arsenic exposure through breast milk in Bangladeshi infants, living in an area with high prevalence of arsenic-rich tube-well water. Methods We analyzed metabolites of inorganic arsenic in breast milk ...

  13. Chemical controls on abiotic and biotic release of geogenic arsenic from Pleistocene aquifer sediments to groundwater.

    Gillispie, Elizabeth C; Andujar, Erika; Polizzotto, Matthew L

    2016-08-10

    Over 150 million people in South and Southeast Asia consume unsafe drinking water from arsenic-rich Holocene aquifers. Although use of As-free water from Pleistocene aquifers is a potential mitigation strategy, such aquifers are vulnerable to geogenic As pollution, placing millions more people at potential risk. The goal of this research was to define chemical controls on abiotic and biotic release of geogenic As to groundwater. Batch incubations of sediments with natural chemical variability from a Pleistocene aquifer in Cambodia were conducted to evaluate how interactions among arsenic, manganese and iron oxides, and dissolved and sedimentary organic carbon influenced As mobilization from sediments. The addition of labile dissolved organic carbon produced the highest concentrations of dissolved As after >7 months, as compared to sediment samples incubated with sodium azide or without added carbon, and the extent of As release was positively correlated with the percent of initial extractable Mn released from the sediments. The mode of As release was impacted by the source of DOC supplied to the sediments, with biological processes responsible for 81% to 85% of the total As release following incubations with lactate and acetate but only up to 43% to 61% of the total As release following incubations with humic and fulvic acids. Overall, cycling of key redox-active elements and organic-carbon reactivity govern the potential for geogenic As release to groundwater, and results here may be used to formulate better predictions of the arsenic pollution potential of aquifers in South and Southeast Asia. PMID:27463026

  14. Composition and recovery method for electrolytic manganese residue

    陶长元; 李明艳; 刘作华; 杜军

    2009-01-01

    According to the statistic analysis,the reserve of manganese in electrolytic manganese residue deposit is over 780 kt. The average contents of available manganese and ammonium reach 3.90% and 1.68% (mass fraction),respectively. Large amount of manganese compounds and ammonium sulfate are detruded without any treatment or recovery. The compositions of the main elements in electrolytic manganese residue were analyzed comprehensively based on the extensive research data. According to the new development of electrolytic manganese residue comprehensively used in recent years,a water washing residue-twice precipitation process was also proposed. The experimental results indicate that manganese dioxide silicon dioxide and calcium sulfate are presented as amorphous state in the manganese residues. The recovery rates of manganese and nitrogen reach up to 99.5% and 94.5 %,respectively. The recovery process can be easily implemented,environment-friendly and fitting for industrial production.

  15. Factors Affecting Arsenic Methylation in Arsenic-Exposed Humans: A Systematic Review and Meta-Analysis

    Shen, Hui; Niu, Qiang; Xu, Mengchuan; Rui, Dongsheng; Xu, Shangzhi; Feng, Gangling; Ding, Yusong; Li, Shugang; Jing, Mingxia

    2016-01-01

    Chronic arsenic exposure is a critical public health issue in many countries. The metabolism of arsenic in vivo is complicated because it can be influenced by many factors. In the present meta-analysis, two researchers independently searched electronic databases, including the Cochrane Library, PubMed, Springer, Embase, and China National Knowledge Infrastructure, to analyze factors influencing arsenic methylation. The concentrations of the following arsenic metabolites increase (p< 0.000001)...

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

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

    2012-01-01

    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 baseline to follow-up 4 to 6 months after the household received the intervention. This was assessed through a pre- and postintervention quiz concerning kn...

  17. Manganese mineralogy and diagenesis in the sedimentary rock record

    Johnson, Jena E.; Webb, Samuel M.; Ma, Chi; Fischer, Woodward W.

    2016-01-01

    Oxidation of manganese (II) to manganese (III,IV) demands oxidants with very high redox potentials; consequently, manganese oxides are both excellent proxies for molecular oxygen and highly favorable electron acceptors when oxygen is absent. The first of these features results in manganese-enriched sedimentary rocks (manganese deposits, commonly Mn ore deposits), which generally correspond to the availability of molecular oxygen in Earth surface environments. And yet because manganese reduction is promoted by a variety of chemical species, these ancient manganese deposits are often significantly more reduced than modern environmental manganese-rich sediments. We document the impacts of manganese reduction and the mineral phases that form stable manganese deposits from seven sedimentary examples spanning from modern surface environments to rocks over 2 billion years old. Integrating redox and coordination information from synchrotron X-ray absorption spectroscopy and X-ray microprobe imaging with scanning electron microscopy and energy and wavelength-dispersive spectroscopy, we find that unlike the Mn(IV)-dominated modern manganese deposits, three manganese minerals dominate these representative ancient deposits: kutnohorite (CaMn(CO3)2), rhodochrosite (MnCO3), and braunite (Mn(III)6Mn(II)O8SiO4). Pairing these mineral and textural observations with previous studies of manganese geochemistry, we develop a paragenetic model of post-depositional manganese mineralization with kutnohorite and calcian rhodochrosite as the earliest diagenetic mineral phases, rhodochrosite and braunite forming secondarily, and later alteration forming Mn-silicates.

  18. Characterization of arsenic-contaminated aquifer sediments from eastern Croatia by ion microbeam, PIXE and ICP-OES techniques

    Highlights: •ICP-OES and PIXE used in the characterization of As-contaminated sediments. •Observed high correlations between the results obtained by those techniques. •Discrepancies observed for Mn, and for the highest As concentrations. •Microbeam analyses showed As association with sulphides and iron. -- Abstract: Groundwater arsenic contamination has been evidenced in eastern Croatia and hydrochemical results suggest that the occurrence of arsenic in the groundwater depends on the local geology, hydrogeology, and geochemical characteristics of the aquifer. In order to perform the sediment characterization and to investigate arsenic association with the other elements in the sediments, 10 samples from two boreholes (PVc-3 and Gundinci 1) in eastern Croatia were analyzed using two techniques: PIXE (without sample pre-treatment) and ICP-OES (after digestion), as well by ion microbeam analyses. The results of the PIXE and ICP-OES techniques showed quite good agreement; however, greater discrepancies were observed at the higher arsenic and manganese mass ratios. According to both techniques, higher As mass ratios were observed in the sediments from the PVc-3 core (up to 651 mg/kg and 491 mg/kg using PIXE and ICP-OES analyses respectively) than from the Gundinci 1 core (up to 60 mg/kg using both techniques). Although arsenic association with Fe is expected, no correlation was observed. The microbeam analyses demonstrated that arsenic is associated with sulphides and iron in the most As-contaminated sample from the PVc-3 core, while this relationship was not evident in the most As-contaminated sample from the Gundinci 1 borehole

  19. Irrigation with oxygen-nanobubble water can reduce methane emission and arsenic dissolution in a flooded rice paddy

    Minamikawa, Kazunori; Takahashi, Masayoshi; Makino, Tomoyuki; Tago, Kanako; Hayatsu, Masahito

    2015-08-01

    A remarkable feature of nanobubbles (commercially available generator. Rice (Oryza sativa L.) growth did not differ between plants irrigated with NB water and those irrigated with control water, but NB water significantly (p rice-growing season by 21%. The amounts of iron, manganese, and arsenic that leached into the drainage water before full rice heading were also reduced by the NB water. Regardless of the water type, weekly-measured CH4 flux was linearly correlated with the leached iron concentration during the rice-growing season (r = 0.74, p rice plants, soil reduction was not enhanced, regardless of the water type. The results indicate that NB water reduced CH4 emission and arsenic dissolution through an oxidative shift of the redox conditions in the flooded soil. We propose the use of NB water as a tool for controlling redox conditions in flooded paddy soils.

  20. Effect of water hyacinth root extract on arsenic level in different organs of arsenic-treated rat

    Shaheen Lipika Quayum

    2007-01-01

    The present study investigated whether the administration of the ethanol extract of water hyacinth (Eichhornia crassipes) ameliorates arsenic from arsenic-treated rats. To induce arsenic accumulation in different organs, arsenic trioxide was administered orally by gavage at a dose of 500 µg/rat/day for 7 days. In search of an effective therapeutic agent to counteract arsenic accumulation and arsenic-induced oxidative stress, different concentrations of ethanol extract of root of water hyacint...

  1. Electrokinetic remediation of manganese and ammonia nitrogen from electrolytic manganese residue.

    Shu, Jiancheng; Liu, Renlong; Liu, Zuohua; Du, Jun; Tao, Changyuan

    2015-10-01

    Electrolytic manganese residue (EMR) is a solid waste found in filters after sulphuric acid leaching of manganese carbonate ore, which mainly contains manganese and ammonia nitrogen and seriously damages the ecological environment. This work demonstrated the use of electrokinetic (EK) remediation to remove ammonia nitrogen and manganese from EMR. The transport behavior of manganese and ammonia nitrogen from EMR during electrokinetics, Mn fractionation before and after EK treatment, the relationship between Mn fractionation and transport behavior, as well as the effects of electrolyte and pretreatment solutions on removal efficiency and energy consumption were investigated. The results indicated that the use of H2SO4 and Na2SO4 as electrolytes and pretreatment of EMR with citric acid and KCl can reduce energy consumption, and the removal efficiencies of manganese and ammonia nitrogen were 27.5 and 94.1 %, respectively. In these systems, electromigration and electroosmosis were the main mechanisms of manganese and ammonia nitrogen transport. Moreover, ammonia nitrogen in EMR reached the regulated level, and the concentration of manganese in EMR could be reduced from 455 to 37 mg/L. In general, the electrokinetic remediation of EMR is a promising technology in the future. PMID:26062467

  2. Arsenic Toxicity in Male Reproduction and Development

    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 a...

  3. Dissolved Air Flotation of arsenic adsorbent particles

    Santander, M.; Valderrama, L.

    2015-01-01

    The removal of arsenic from synthetic effluent was studied using the adsorbent particle flotation technique (APF) and dissolved air flotation (DAF). A sample of an iron mineral was used as adsorbent particles of arsenic, ferric chloride as coagulant, cationic polyacrylamide (NALCO 9808) as flocculants, and sodium oleate as collector. Adsorption studies to determine the pH influence, contact time, and adsorbent particles concentration on the adsorption of arsenic were carried out along with fl...

  4. Current developments in toxicological research on arsenic

    Bolt, Hermann M.

    2013-01-01

    There is a plethora of recent publications on all aspects relevant to the toxicology of arsenic (As). Over centuries exposures to arsenic continue to be a major public health problem in many countries. In particular, the occurrence of high As concentrations in groundwater of Southeast Asia receives now much attention. Therefore, arsenic is a high-priority matter for toxicological research. Key exposure to As are (traditional) medicines, combustion of As-rich coal, presence of As in groundwate...

  5. Manganese exposure in foundry furnacemen and scrap recycling workers

    Lander, F; Kristiansen, J; Lauritsen, Jens

    1999-01-01

    Cast iron products are alloyed with small quantities of manganese, and foundry furnacemen are potentially exposed to manganese during tapping and handling of smelts. Manganese is a neurotoxic substance that accumulates in the central nervous system, where it may cause a neurological disorder that...... bears many similarities to Parkinson's disease. The aim of the study was to investigate the sources and levels of manganese exposure in foundry furnacemen by a combined measuring of blood-manganese (B-Mn) and manganese in ambient air (air-Mn)....

  6. Applications of nano-structured metal oxides for treatment of arsenic in water and for antimicrobial coatings

    Sadu, Rakesh Babu

    Dependency of technology has been increasing radically through cellular phones for communication, data storage devices for education, drinking water purifiers for healthiness, antimicrobial-coated textiles for cleanliness, nanomedicines for deadliest diseases, solar cells for natural power, nanorobots for engineering and many more. Nanotechnology develops many unprecedented products and methodologies with its adroitness in this modern scientific world. Syntheses of nanomaterials play a significant role in the development of technology. Solution combustion and hydrothermal syntheses produce many nanomaterials with different structures and pioneering applications. Nanometal oxides, like titania, silver oxide, manganese oxide and iron oxide have their unique applications in engineering, chemistry and biochemistry. Likewise, this study talks about the syntheses and applications of nanomaterials such as magnetic graphene nanoplatelets (M-Gras) decorated with uniformly dispersed NPs, manganese doped titania nanotubes (Mn-TNTs), and silver doped titania nanopartcles (nAg-TNPs) and their polyurethane based polymer nanocomposite coating (nAg-TiO2 /PU). Basically, M-Gras, and Mn-TNTs were applied for the treatment of arsenic contaminated water, and nAg- TiO2/PU applied for antimicrobial coatings on textiles. Adsorption of arsenic over Mn- TNTs, and M-Gras was discussed while considering all the regulations of arsenic contamination in drinking water and oxidation of arsenic over Mn-TNTs also discussed with the possible surface reactions. Silver doped titania and its polyurethane nanocomposite was coated on polyester fabric and examined the coated fabric for bactericidal activity for gram-negative (E. coli) and gram-positive ( S. epidermidis) bacteria. This study elucidates the development of suitable nanomaterials and their applications to treat or rectify the environmental hazards while following the scientific standards and regulations.

  7. Arsenic in the soils of Zimapan, Mexico

    Arsenic concentrations of 73 soil samples collected in the semi-arid Zimapan Valley range from 4 to 14 700 mg As kg-1. Soil arsenic concentrations decrease with distance from mines and tailings and slag heaps and exceed 400 mg kg-1 only within 500 m of these arsenic sources. Soil arsenic concentrations correlate positively with Cu, Pb, and Zn concentrations, suggesting a strong association with ore minerals known to exist in the region. Some As was associated with Fe and Mn oxyhydroxides, this association is less for contaminated than for uncontaminated samples. Very little As was found in the mobile water-soluble or exchangeable fractions. The soils are not arsenic contaminated at depths greater than 100 cm below the surface. Although much of the arsenic in the soils is associated with relatively immobile solid phases, this represents a long-term source of arsenic to the environment. -- Much of the arsenic is relatively immobile but presents long-term source of arsenic

  8. Acute arsenic poisoning in two siblings.

    Lai, Melisa W; Boyer, Edward W; Kleinman, Monica E; Rodig, Nancy M; Ewald, Michele Burns

    2005-07-01

    We report a case series of acute arsenic poisoning of 2 siblings, a 4-month-old male infant and his 2-year-old sister. Each child ingested solubilized inorganic arsenic from an outdated pesticide that was misidentified as spring water. The 4-month-old child ingested a dose of arsenic that was lethal despite extraordinary attempts at arsenic removal, including chelation therapy, extracorporeal membrane oxygenation, exchange transfusion, and hemodialysis. The 2-year-old fared well with conventional therapy. PMID:15995066

  9. XAS Studies of Arsenic in the Environment

    Arsenic is present in low concentrations in much of the Earth's crust and changes in its speciation are vital to understanding its transport and toxicity in the environment. We have used X-ray absorption spectroscopy to investigate the coordination sites of arsenic in a wide variety of samples, including soil and earthworm tissues from arsenic-contaminated land, and human hair and nail samples from people exposed to arsenic in Cambodia. Our results confirm the effectiveness of using X-ray absorption near edge structure (XANES) and X-ray absorption fine structure (EXAFS) spectroscopy to determine speciation changes in environmental samples

  10. Manganese-electrolysed slag treatment: bioleaching of manganese by Fusarium sp.

    Cao, Jian-Bing; Li, Xiao-Ming; Ouyang, Yu-Zhu; Zheng, Wei; Wang, Dong-Bo; Shen, Ting-Ting; Yue, Xiu; Yang, Qia

    2012-06-01

    A fungi strain named Fusarium sp. was isolated from manganese-electrolysed slag by using a gradient dilution spread plate method, identified by 26S RNA sequence analysis and phylogenetic tree analysis, and explored for the bioleaching capacity to manganese (II) from manganese-electrolysed slag in liquid mineral medium under different environmental conditions, including system temperature, incubator rotation speed and initial pH value. DNA sequence and phylogenetic analysis indicated the name of this fungi strain, that is, Fusarium sp., and higher bioleaching efficiencies (71.6%) of manganese by this fungi were observed when the bioleaching was carried out under the optimized conditions as follows: contact time: 72 h; system temperature: 28 degrees C; inoculums concentration: 2% (v/v); incubator rotation speed: 150 rpm; pH 4.0. Because of its low cost, environment friendliness and better efficiency, the bioleaching technique will have a significant impact on manganese-electrolysed slag pollution mitigation. PMID:22856303

  11. Addressivity in cogenerative dialogues

    Hsu, Pei-Ling

    2014-03-01

    Ashraf Shady's paper provides a first-hand reflection on how a foreign teacher used cogens as culturally adaptive pedagogy to address cultural misalignments with students. In this paper, Shady drew on several cogen sessions to showcase his journey of using different forms of cogens with his students. To improve the quality of cogens, one strategy he used was to adjust the number of participants in cogens. As a result, some cogens worked and others did not. During the course of reading his paper, I was impressed by his creative and flexible use of cogens and at the same time was intrigued by the question of why some cogens work and not others. In searching for an answer, I found that Mikhail Bakhtin's dialogism, especially the concept of addressivity, provides a comprehensive framework to address this question. In this commentary, I reanalyze the cogen episodes described in Shady's paper in the light of dialogism. My analysis suggests that addressivity plays an important role in mediating the success of cogens. Cogens with high addressivity function as internally persuasive discourse that allows diverse consciousnesses to coexist and so likely affords productive dialogues. The implications of addressivity in teaching and learning are further discussed.

  12. Hydrogeological and geochemical investigations of elevated arsenic (As) abundances in groundwater in Ireland

    Full text: This study will use hydrogeology, geochemistry and chemical speciation studies to investigate the presence of elevated arsenic (As) abundances in groundwater in Ireland. Comparative studies of groundwater, bedrock and mineral chemistry will be linked to hydrogeology, GIS and statistical studies. This approach will facilitate characterization of the temporal and spatial distribution of As as a function of groundwater and bedrock geology using the pressures, pathways and receptors approach. Arsenic speciation studies will determine As toxicity, bioavailability and potential for migration in this environment thus addressing human health issues. (author)

  13. Sorption properties of hydrous manganese oxide for the removal of radioactive manganese from aqueous solution

    Radioactive manganese (54Mn) is formed in the structural and clad components of fast nuclear reactors due to the high energy neutron flux encountered in the core. It is a corrosion activation product having a half-life of 312.5 days and gamma energy of 835 keV. Hence, its removal from the waste which generates after washing the above mentioned components is very important. The removal properties of radioactive manganese, 54Mn, from an aqueous solution were studied here in a batch process using hydrous manganese oxide (HMO) coated with polyurethane foam as an inorganic sorbent. The HMO was synthesized by alkaline precipitation in air using manganese sulphate monohydrate and potassium permanganate. The synthesized material was found to be in powder form which took lot of time for settlement in solution; hence, it was coated with polyurethane foam, so that it can be easily used in a batch process. The removal of the radioisotope by the sorbent was studied by varying different experimental conditions such as solution pH, contact time, and effect of presence of other divalent ions. The studies carried out in our laboratory found that the sorption of manganese by hydrous manganese oxide followed pseudo-second order kinetics. On the other hand, with increasing pH of the solution (pH range studied: 1-8), the removal of manganese by the sorbent also increases until pH reaches 4.5, after that the sorption was almost same. The present studies confirmed that in the presence of other divalent ions, e.g. cobalt (ii) ions, the sorption was effected which may be due to the sorption of both the ions on hydrous manganese oxide. The sorption was very fast and more than 95% of manganese was removed within one hour of contact with hydrous manganese oxide. (author)

  14. Manganese in dwarf spheroidal galaxies

    North, P; Jablonka, P; Hill, V; Shetrone, M; Letarte, B; Lemasle, B; Venn, K A; Battaglia, G; Tolstoy, E; Irwin, M J; Primas, F; Francois, P

    2012-01-01

    We provide manganese abundances (corrected for the effect of the hyperfine structure) for a large number of stars in the dwarf spheroidal galaxies Sculptor and Fornax, and for a smaller number in the Carina and Sextans dSph galaxies. Abundances had already been determined for a number of other elements in these galaxies, including alpha and iron-peak ones, which allowed us to build [Mn/Fe] and [Mn/alpha] versus [Fe/H] diagrams. The Mn abundances imply sub-solar [Mn/Fe] ratios for the stars in all four galaxies examined. In Sculptor, [Mn/Fe] stays roughly constant between [Fe/H]\\sim -1.8 and -1.4 and decreases at higher iron abundance. In Fornax, [Mn/Fe] does not vary in any significant way with [Fe/H]. The relation between [Mn/alpha] and [Fe/H] for the dSph galaxies is clearly systematically offset from that for the Milky Way, which reflects the different star formation histories of the respective galaxies. The [Mn/alpha] behavior can be interpreted as a result of the metal-dependent Mn yields of type II and ...

  15. Infrared spectrum of arsenic pentafluoride

    After a literature review about arsenic fluorides, we give several methods of obtaining very pure AsF5 in order to ascertain the right spectrum of this compound. Our spectra fit well with Akers's observations, and we note that AsF5 structure can be explained in terms of C3v molecular symmetry, with the As-F bond stretching lying at 786 cm-1 and 811 cm-1. (author)

  16. Arsenic (+3 oxidation state) methyltransferase and the inorganic arsenic methylation phenotype

    Inorganic arsenic is enzymatically methylated; hence, its ingestion results in exposure to the parent compound and various methylated arsenicals. Both experimental and epidemiological evidences suggest that some of the adverse health effects associated with chronic exposure to inorganic arsenic may be mediated by these methylated metabolites. If i As methylation is an activation process, then the phenotype for inorganic arsenic methylation may determine risk associated with exposure to this metalloid. We examined inorganic arsenic methylation phenotypes and arsenic (+3 oxidation state) methyltransferase genotypes in four species: three that methylate inorganic arsenic (human (Homo sapiens), rat (Rattus norwegicus), and mouse (Mus musculus)) and one that does not methylate inorganic arsenic (chimpanzee, Pan troglodytes). The predicted protein products from arsenic (+3 oxidation state) methyltransferase are similar in size for rat (369 amino acid residues), mouse (376 residues), and human (375 residues). By comparison, a 275-nucleotide deletion beginning at nucleotide 612 in the chimpanzee gene sequence causes a frameshift that leads to a nonsense mutation for a premature stop codon after amino acid 205. The null phenotype for inorganic arsenic methylation in the chimpanzee is likely due to the deletion in the gene for arsenic (+3 oxidation state) methyltransferase that yields an inactive truncated protein. This lineage-specific loss of function caused by the deletion event must have occurred in the Pan lineage after Homo-Pan divergence about 5 million years ago

  17. Arsenic Removal by Liquid Membranes

    Tiziana Marino

    2015-03-01

    Full Text Available Water contamination with harmful arsenic compounds represents one of the most serious calamities of the last two centuries. Natural occurrence of the toxic metal has been revealed recently for 21 countries worldwide; the risk of arsenic intoxication is particularly high in Bangladesh and India but recently also Europe is facing similar problem. Liquid membranes (LMs look like a promising alternative to the existing removal processes, showing numerous advantages in terms of energy consumption, efficiency, selectivity, and operational costs. The development of different LM configurations has been a matter of investigation by several researching groups, especially for the removal of As(III and As(V from aqueous solutions. Most of these LM systems are based on the use of phosphine oxides as carriers, when the metal removal is from sulfuric acid media. Particularly promising for water treatment is the hollow fiber supported liquid membrane (HFSLM configuration, which offers high selectivity, easy transport of the targeted metal ions, large surface area, and non-stop flow process. The choice of organic extractant(s plays an essential role in the efficiency of the arsenic removal. Emulsion liquid membrane (ELM systems have not been extensively investigated so far, although encouraging results have started to appear in the literature. For such LM configuration, the most relevant step toward efficiency is the choice of the surfactant type and its concentration.

  18. Impaired arsenic metabolism in children during weaning

    Background: Methylation of inorganic arsenic (iAs) via one-carbon metabolism is a susceptibility factor for a range of arsenic-related health effects, but there is no data on the importance of arsenic metabolism for effects on child development. Aim: To elucidate the development of arsenic metabolism in early childhood. Methods: We measured iAs, methylarsonic acid (MA) and dimethylarsinic acid (DMA), the metabolites of iAs, in spot urine samples of 2400 children at 18 months of age. The children were born to women participating in a population-based longitudinal study of arsenic effects on pregnancy outcomes and child development, carried out in Matlab, a rural area in Bangladesh with a wide range of arsenic concentrations in drinking water. Arsenic metabolism was evaluated in relation to age, sex, anthropometry, socio-economic status and arsenic exposure. Results: Arsenic concentrations in child urine (median 34 μg/L, range 2.4-940 μg/L), adjusted to average specific gravity of 1.009 g/mL, were considerably higher than that measured at 3 months of age, but lower than that in maternal urine. Child urine contained on average 12% iAs, 9.4% MA and 78% DMA, which implies a marked change in metabolite pattern since infancy. In particular, there was a marked increase in urinary %MA, which has been associated with increased risk of health effects. Conclusion: The arsenic metabolite pattern in urine of children at 18 months of age in rural Bangladesh indicates a marked decrease in arsenic methylation efficiency during weaning.

  19. Arsenic Adsorption Onto Iron Oxides Minerals

    Aredes, S.; Klein, B.; Pawlik, M.

    2004-12-01

    The predominant form of arsenic in water is as an inorganic ion. Under different redox conditions arsenic in water is stable in the +5 and +3 oxidation states. Arsenic oxidation state governs its toxicity, chemical form and solubility in natural and disturbed environments. As (III) is found in anoxic environments such as ground water , it is toxic and the common species is the neutral form, H3AsO3. As (V) is found in aerobic conditions such as surface water, it is less toxic and the common species in water are: H2AsO4 - and HAsO4 {- 2}. The water pH determines the predominant arsenate or arsenite species, however, both forms of arsenic can be detected in natural water systems. Iron oxides minerals often form in natural waters and sediments at oxic-anoxic boundaries. Over time they undergo transformation to crystalline forms, such as goethite or hematite. Both As(V) and As(III) sorbs strongly to iron oxides, however the sorption behavior of arsenic is dependent on its oxidation state and the mineralogy of the iron oxides. Competition between arsenic and others ions, such fluoride, sulphate and phosphate also play a role. On the other hand, calcium may increase arsenic adsorption onto iron oxides. Electrokinetic studies and adsorption experiments were carried out in order to determine which conditions favour arsenic adsorption. Hematite, goethite and magnetite as iron based sorbents were used. Test were also conducted with a laterite soil rich in iron minerals. The focus of this study is to evaluate physical and chemical conditions which favour arsenic adsorption onto iron oxides minerals, the results contribute to an understanding of arsenic behaviour in natural and disturbed environments. Furthermore, results could contribute in developing an appropriate remediation technology for arsenic removal in water using iron oxides minerals.

  20. Chromosome analysis of arsenic affected cattle

    S. Shekhar

    2014-10-01

    Full Text Available Aim: The aim was to study the chromosome analysis of arsenic affected cattle. Materials and Methods: 27 female cattle (21 arsenic affected and 6 normal were selected for cytogenetical study. The blood samples were collected, incubated, and cultured using appropriate media and specific methods. The samples were analyzed for chromosome number and morphology, relative length of the chromosome, arm ratio, and centromere index of X chromosome and chromosomal abnormalities in arsenic affected cattle to that of normal ones. Results: The diploid number of metaphase chromosomes in arsenic affected cattle as well as in normal cattle were all 2n=60, 58 being autosomes and 2 being sex chromosomes. From the centromeric position, karyotyping studies revealed that all the 29 pair of autosomes was found to be acrocentric or telocentric, and the sex chromosomes (XX were submetacentric in both normal and arsenic affected cattle. The relative length of all the autosome pairs and sex chrosomosome pair was found to be higher in normal than that of arsenic affected cattle. The mean arm ratio of X-chromosome was higher in normal than that of arsenic affected cattle, but it is reverse in case of centromere index value of X-chromosome. There was no significant difference of arm ratio and centromere index of X-chromosomes between arsenic affected and normal cattle. No chromosomal abnormalities were found in arsenic affected cattle. Conclusion: The chromosome analysis of arsenic affected cattle in West Bengal reported for the first time in this present study which may serve as a guideline for future studies in other species. These reference values will also help in comparison of cytological studies of arsenic affected cattle to that of various toxicants.

  1. Interactions between arsenic species and marine algae

    Sanders, J.G.

    1978-01-01

    The arsenic concentration and speciation of marine algae varies widely, from 0.4 to 23 ng.mg/sup -1/, with significant differences in both total arsenic content and arsenic speciation occurring between algal classes. The Phaeophyceae contain more arsenic than other algal classes, and a greater proportion of the arsenic is organic. The concentration of inorganic arsenic is fairly constant in macro-algae, and may indicate a maximum level, with the excess being reduced and methylated. Phytoplankton take up As(V) readily, and incorporate a small percentage of it into the cell. The majority of the As(V) is reduced, methylated, and released to the surrounding media. The arsenic speciation in phytoplankton and Valonia also changes when As(V) is added to cultures. Arsenate and phosphate compete for uptake by algal cells. Arsenate inhibits primary production at concentrations as low as 5 ..mu..g.1/sup -1/ when the phosphate concentration is low. The inhibition is competitive. A phosphate enrichment of > 0.3 ..mu..M alleviates this inhibition; however, the As(V) stress causes an increase in the cell's phosphorus requirement. Arsenite is also toxic to phytoplankton at similar concentrations. Methylated arsenic species did not affect cell productivity, even at concentrations of 25 ..mu..g.1/sup -1/. Thus, the methylation of As(V) by the cell produces a stable, non-reactive compound which is nontoxic. The uptake and subsequent reduction and methylation of As(V) is a significant factor in determining the arsenic biogeochemistry of productive systems, and also the effect that the arsenic may have on algal productivity. Therefore, the role of marine algae in determining the arsenic speciation of marine systems cannot be ignored. (ERB)

  2. ARSENIC REMOVAL AND ECOLOGICALLY SAFE CONTAINMENT OF ARSENIC-WASTE: A SUSTAINABLE SOLUTION FOR ARSENIC CRISIS IN CAMBODIA

    An appalling degree of arsenic contamination in groundwater has affected more than a million people in wide region of Mekong delta flood plain in Cambodia. Arsenic is by far the most toxic species of all naturally occurring groundwater contaminants and disposal of removed arse...

  3. Redox-controlled groundwater mobilization of soil arsenic: A case study and model

    Lieberman, J.; Gerath, M.; Duvel, W.

    1996-12-31

    Arsenic contaminates the groundwater beneath and downstream from a chemical manufacturing plant, although historical waste emissions from the plant have consisted principly of isopropanol, and fatty acids. Groundwater and soil analysis of organics, metals, anions, D.O. (dissolved oxygen), and redox potential are consistent with a model for redox-controlled mobilization of that arsenic which is naturally present in the soil at background concentrations of around 10 mg/kg. According to this model, aerobic biodegradation of organic compounds from the plant`s waste stream consumes D.O. and lowers the redox potential of portions of the aquifer. Somewhere below 0.5 mg/l D.O., particles of iron and manganese hydroxide tend to dissolve and release the arsenic adsorbed to their surfaces. Bacterial mediation and organic complexation are then believed to determine the formation of soluble arsenite and arsenate complexes. A numerical flow/transport/reaction model of the plant site was set up using the BIOPLUME II code in order to simulate bacterial D.O. consumption in the aquifer and evaluate remedial alternatives. Modeling results show that site cleanup (increase of D.O. above 0.5 mg/l) will require approximately nine years with no action, four years with excavation of the source leachfield, and two years with source excavation plus oxygen injection. A combination of soil excavation and oxygen injection is presently under design in order to quickly reduce the consumption of D.O. in the saturated aquifer and remove a necessary condition for arsenic mobilization.

  4. Manganese and acute paranoid psychosis: A case report

    W.M.A. Verhoeven (Wim); J.I.M. Egger (Jos); H.J. Kuijpers (Harold)

    2011-01-01

    textabstractIntroduction: Manganese regulates many enzymes and is essential for normal development and body function. Chronic manganese intoxication has an insidious and progressive course and usually starts with complaints of headache, fatigue, sleep disturbances, irritability and emotional instabi

  5. Manganese and acute paranoid psychosis: a case report

    Verhoeven, W.M.A.; Egger, J.I.M.; Kuijpers, H.J.H.

    2011-01-01

    Introduction Manganese regulates many enzymes and is essential for normal development and body function. Chronic manganese intoxication has an insidious and progressive course and usually starts with complaints of headache, fatigue, sleep disturbances, irritability and emotional instability. Later,

  6. Long-Term Exposure to Low-Level Arsenic in Drinking Water and Diabetes Incidence

    Bräuner, Elvira; Nordsborg, Rikke Baastrup; Andersen, Zorana;

    2014-01-01

    Background: Established causes of diabetes do not fully explain the epidemic. High level arsenic exposure has been implicated in diabetes risk but the effect of low-level arsenic exposure in drinking water remains unclear. Objective: To determine if long-term exposure to low-level arsenic in...... drinking water in Denmark is associated with increased risk of diabetes using a large prospective cohort. Methods: During 1993-1997 we recruited 57,053 persons. We followed each cohort member for diabetes occurrence from enrollment until 31 December 2006. We traced and geocoded residential addresses of the...... diabetes incidence, separately for two definitions of diabetes: all cases and a more strict definition, where cases of diabetes based solely on blood glucose results were excluded. Results: Over a mean follow-up of 9.7 years of 52,931 eligible subjects, there were 4,304 (8.1%) diabetes cases in total, and...

  7. Addressing the nuclear misconception

    There is a perception, fostered and encouraged by the anti-nuclear groups, that the nuclear industry generates large quantities of waste with no idea how to deal with it, that it is unsafe, uneconomic, and environmentally damaging. The task is to change these perceptions, by demonstrating that the industry is not a problem in itself, but in fact provides solutions to problems. This paper, while primarily concerned with waste, addresses all of these issues as each has a bearing on the perception of the industry and therefore must be considered when addressing the issue of waste. The paper concludes that evidence exists to support the industry view, but that the mission of the industry should be to change the perception of the industry, by influencing and working together with its stake holders to address their concerns, rather than merely presenting more and more facts. (author)

  8. Addressing the nuclear misconception

    There is a perception, fostered and encouraged by the anti-nuclear groups, that the nuclear industry generates large quantities of waste with no idea how to deal with it, is unsafe, uneconomic, and environmentally damaging. The task of the industry is to change the perception by demonstrating that the industry provides solutions to problems, and is not a problem in itself. This paper, whilst primarily concerned with waste, addresses all of these issues as each has a bearing on the perception of the industry and therefore must be considered when addressing the issue of waste. The paper concludes that evidence exists to support the industry, but that the mission of the industry should be to change the perception of it, by influencing and working together with its stakeholders to address their concerns, rather than merely presenting more and more facts. (author)

  9. The catalytic oxidation of manganese in water treatment clarification processes

    Lloyd, A.

    1982-01-01

    The removal of dissolved manganese in water treatment floc blanket clarifiers has been studied. The removal mechanisms may be broadly classed as adsorption and oxidation. Adsorption of manganese (II) occurs rapidly and is completed in less than five minutes under conditions prevailing in a floe blanket clarifier. The extent of adsorption is determined by pH, iron and manganese concentrations. Manganese adsorption is relatively insensitive to the concentration of other cations and anions prese...

  10. Reductive Acid Leaching of Low Grade Manganese Ores

    Alok Prasad Das; Sarpras Swain; Shriyanka Panda; Nilotpala Pradhan; Lala Behari Sukla

    2012-01-01

    Manganese recoveries from low-grade ores using organic acids as reducing agents were investigated in the present work. The acid leaching potential of both oxalic acid and citric acid were estimated. Manganese leaching amount were measured by using standard manganese curve and estimated by titration method. Effects of various acid concentrations on leaching efficiency were studied. The observed result suggested prominent manganese recovery of 66% by oxalic acid at 2 M concentration whereas cit...

  11. Bioaccumulation of Arsenic by Fungi

    Ademola O. Adeyemi

    2009-01-01

    Full Text Available Problem statement: Arsenic is a known toxic element and its presence and toxicity in nature is a worldwide environmental problem. The use of microorganisms in bioremediation is a potential method to reduce as concentration in contaminated areas. Approach: In order to explore the possible bioremediation of this element, three filamentous fungi-Aspergillus niger, Serpula himantioides and Trametes versicolor were investigated for their potential abilities to accumulate (and possibly solubilize arsenic from an agar environment consisting of non buffered mineral salts media amended with 0.2, 0.4, 0.6 and 0.8% (w/v arsenopyrite (FeAsS. Growth rates, dry weights, arsenic accumulation and oxalate production by the fungi as well as the pH of the growth media were all assessed during this study. Results: There was no visible solubilization of FeAsS particles underneath any of the growing fungal colonies or elsewhere in the respective agar plates. No specific patterns of growth changes were observed from the growth ratios of the fungi on agar amended with different amounts of FeAsS although growth of all fungi was stimulated by the incorporation of varying amounts of FeAsS into the agar with the exception of A. niger on 0.4% (w/v amended agar and T. versicolor on 0.8% (w/v amended agar. The amounts of dry weights obtained for all three fungi also did not follow any specific patterns with different amounts of FeAsS and the quantities obtained were in the order A. niger > S. himantioides > T. versicolor. All fungi accumulated as in their biomasses with all amounts of FeAsS although to varying levels and T. versicolor was the most effective with all amounts of FeAsS while A. niger was the least effective. Conclusion: The accumulation of arsenic in the biomasses of the test fungi as shown in this study may suggested a role for fungi through their bioaccumulating capabilities as agents in the possible bioremediation of arsenic contaminated environments.

  12. ARSENIC EFFECTS ON TELOMERE AND TELOMERASE ACTIVITY

    Arsenic effects on telomere and telomerase activity. T-C. Zhang, M. T. Schmitt, J. Mo, J. L. Mumford, National Research Council and U.S Environmental Protection Agency, NHEERL, Research Triangle Park, NC 27711Arsenic is a known carcinogen and also an anticancer agent for acut...

  13. 29 CFR 1915.1018 - Inorganic arsenic.

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Inorganic arsenic. 1915.1018 Section 1915.1018 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1018 Inorganic arsenic. Note: The requirements applicable to shipyard employment under...

  14. 29 CFR 1926.1118 - Inorganic arsenic.

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Inorganic arsenic. 1926.1118 Section 1926.1118 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Inorganic arsenic. Note: The requirements applicable to construction work under this section are...

  15. The Chemistry and Metabolism of Arsenic

    I. IntrodctionA century of study of the process by which many organisms convert inorganic arsenic into an array of methylated metabolites has answered many questions and has posed some new ones. The capacity of microorganisms to. form volatile arsenic compounds was first recogniz...

  16. Arsenic Consumption in the United States.

    Wilson, Denise

    2015-10-01

    Exposure limits for arsenic in drinking water and minimal risk levels (MRLs) for total dietary exposure to arsenic have long been established in the U.S. Multiple studies conducted over the last five years have detected arsenic in foods and beverages including juice, rice, milk, broth (beef and chicken), and others. Understanding whether or not each of these foods or drinks is a concern to certain groups of individuals requires examining which types of and how much arsenic is ingested. In this article, recent studies are reviewed and placed in the context of consumption patterns. When single sources of food or drink are considered in isolation, heavy rice eaters can be exposed to the most arsenic among adults while infants consuming formula containing contaminated organic brown rice syrup are the most exposed group among children. Most food and drink do not contain sufficient arsenic to exceed MRLs. For individuals consuming more than one source of contaminated water or food, however, adverse health effects are more likely. In total, recent studies on arsenic contamination in food and beverages emphasize the need for individual consumers to understand and manage their total dietary exposure to arsenic. PMID:26591332

  17. Arsenic and human health effects: A review.

    Abdul, Khaja Shameem Mohammed; Jayasinghe, Sudheera Sammanthi; Chandana, Ediriweera P S; Jayasumana, Channa; De Silva, P Mangala C S

    2015-11-01

    Arsenic (As) is ubiquitous in nature and humans being exposed to arsenic via atmospheric air, ground water and food sources are certain. Major sources of arsenic contamination could be either through geological or via anthropogenic activities. In physiological individuals, organ system is described as group of organs that transact collectively and associate with other systems for conventional body functions. Arsenic has been associated with persuading a variety of complications in body organ systems: integumentary, nervous, respiratory, cardiovascular, hematopoietic, immune, endocrine, hepatic, renal, reproductive system and development. In this review, we outline the effects of arsenic on the human body with a main focus on assorted organ systems with respective disease conditions. Additionally, underlying mechanisms of disease development in each organ system due to arsenic have also been explored. Strikingly, arsenic has been able to induce epigenetic changes (in utero) and genetic mutations (a leading cause of cancer) in the body. Occurrence of various arsenic induced health effects involving emerging areas such as epigenetics and cancer along with their respective mechanisms are also briefly discussed. PMID:26476885

  18. Addressing Sexual Harassment

    Young, Ellie L.; Ashbaker, Betty Y.

    2008-01-01

    This article discusses ways on how to address the problem of sexual harassment in schools. Sexual harassment--simply defined as any unwanted and unwelcome sexual behavior--is a sensitive topic. Merely providing students, parents, and staff members with information about the school's sexual harassment policy is insufficient; schools must take…

  19. 40 CFR 721.10003 - Manganese heterocyclic tetraamine complex (generic).

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Manganese heterocyclic tetraamine... Specific Chemical Substances § 721.10003 Manganese heterocyclic tetraamine complex (generic). (a) Chemical... as manganese heterocyclic tetraamine complex (PMNs P-98-625/626/627/628/629 and P-00-614/617)...

  20. Studies on inorganic exchangers - manganese dioxide

    As a part of investigation of separation processes for long lived fission products from fuel reprocessing solution, manganese dioxide has been studied as an ion exchanger for cerium using 137Cs, 106Ru, 141Ce, sup(85,89)Sr, 95Zr and 95Nb as tracers. For different concentrations of HNO3, distribution ratios and breakthrough capacities were determined. Cerium was eluted by manganese sulphate and nitric acid. Results show that : (1) at all acidities cerium is adsorbed with almost no uptake of other rare earths, sodium, uranium and plutonium, (2) Ce (IV) gives better adsorption than Ce(III), (3) a combination of manganese sulphate (1 mg/ml) and 3M nitric acid elutes 99% cerium in 5-6 column volumes and (4) as for effect of absorption-elution cycles on MnO2 column, initially there is a decrease in capacity of cerium uptake but thereafter the capacity remains constant. (M.G.B.)

  1. Filling Narrow Trenches by Iodine-Catalyzed CVD of Copper and Manganese on Manganese Nitride Barrier/Adhesion Layers

    Gordon, Roy Gerald; Lin, Youbo; Au, Yeung Billy

    2011-01-01

    We present a process for the void-free filling of sub-100 nm trenches with copper or copper-manganese alloy by chemical vapor deposition (CVD). Conformally deposited manganese nitride serves as an underlayer that initially chemisorbs iodine. CVD of copper or copper-manganese alloy releases the adsorbed iodine atoms from the surface of the manganese nitride, allowing iodine to act as a surfactant catalyst floating on the surface of the growing copper layer. The iodine increases the growth rate...

  2. Saturation models of arsenic, cobalt, chromium and manganese bioaccumulation by Hyalella azteca

    Norwood, W.P. [Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1 (Canada) and Aquatic Ecosystems Protection Research Branch, National Water Research Institute, Environment Canada, P.O. Box 5050, Burlington, ON L7R 4A6 (Canada)]. E-mail: warren.norwood@ec.gc.ca; Borgmann, U. [Aquatic Ecosystems Protection Research Branch, National Water Research Institute, Environment Canada, P.O. Box 5050, Burlington, ON L7R 4A6 (Canada); Dixon, D.G. [Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1 (Canada)

    2006-10-15

    Bioaccumulation of As, Co, Cr and Mn by the benthic amphipod Hyalella azteca in Burlington City tap (Lake Ontario) water was measured in 4-week tests. Bioaccumulation increased with exposure concentration and demonstrated an excellent fit to a saturation model (r {sup 2}: 0.819, 0.838, 0.895 and 0.964 for As, Co, Cr and Mn, respectively). The proportion of total body Mn eliminated during a 24-h depuration period decreased as Mn body concentration increased, apparently due to a saturation of the elimination rate. The high maximum body concentration of 116,000 nmol g{sup -1} appears to result from the saturation of the Mn excretion which is slightly greater than the maximum Mn uptake rate. Elimination rates for As, Co and Cr were not dependent on body concentration. The four elements were not physiologically regulated in Hyalella. Their body concentrations should be good indicators of bioavailability and useful for environmental assessment. - Bioaccumulation of As, Co, Cr and Mn follow a saturation model in Hyalella azteca and can be useful for environmental assessment.

  3. Methylation of inorganic arsenic by murine fetal tissue explants.

    Broka, Derrick; Ditzel, Eric; Quach, Stephanie; Camenisch, Todd D

    2016-07-01

    Although it is generally believed that the developing fetus is principally exposed to inorganic arsenic and the methylated metabolites from the maternal metabolism of arsenic, little is known about whether the developing embryo can autonomously metabolize arsenic. This study investigates inorganic arsenic methylation by murine embryonic organ cultures of the heart, lung, and liver. mRNA for AS3mt, the gene responsible for methylation of arsenic, was detected in all embryonic tissue types studied. In addition, methylated arsenic metabolites were generated by all three tissue types. The fetal liver explants yielded the most methylated arsenic metabolites (∼7% of total arsenic/48 h incubation) while the heart, and lung preparations produced slightly greater than 2% methylated metabolites. With all tissues the methylation proceeded mostly to the dimethylated arsenic species. This has profound implications for understanding arsenic-induced fetal toxicity, particularly if the methylated metabolites are produced autonomously by embryonic tissues. PMID:26446802

  4. Arsenic Uptake by Muskmelon (Cucumis melo) Plants from Contaminated Water.

    Hettick, Bryan E; Cañas-Carrell, Jaclyn E; Martin, Kirt; French, Amanda D; Klein, David M

    2016-09-01

    Arsenic is a carcinogenic element that occurs naturally in the environment. High levels of arsenic are found in water in some parts of the world, including Texas. The aims of this study were to determine the distribution of arsenic in muskmelon (Cucumis melo) plants accumulated from arsenic spiked water and to observe effects on plant biomass. Plants were grown and irrigated using water spiked with variable concentrations of arsenic. Inductively coupled plasma mass spectrometry was used to quantify arsenic in different parts of the plant and fruit. Under all conditions tested in this study, the highest concentrations of arsenic were found in the leaves, soil, and roots. Arsenic in the water had no significant effect on plant biomass. Fruits analyzed in this study had arsenic concentrations of 101 μg/kg or less. Consuming these fruits would result in less arsenic exposure than drinking water at recommended levels. PMID:27460822

  5. Kinetics of Nitrogen Diffusion in Granular Manganese

    ZHANG Jin-zhu; XU Chu-shao; ZHAO Yue-ping

    2008-01-01

    The kinetics and the influence of time on granular manganese nitriding were studied by means of a vacuum resistance furnace, X-ray diffraction technique, and LECO TC-436 oxygen/nitrogen determinator. The longer the nitriding time, the more the nitrogen pickup. Except for a trace of oxide MnO that developed, the metal manganese could thoroughly be nitrided to form Mn4N and a little ζ-phase (the stoichiometric components as Mn2N) with the nitriding time lasting. A kinetic model is developed to reveal the nitriding situation and agrees well with the experimental results.

  6. Luminescence channels of manganese-doped spinel

    Two independent luminescence channels are observed from manganese-doped spinel Mn:MgAl2O4. The luminescence around 520 nm is assigned to transition from the lowest electronic excited state 4T1 to the ground state 6A1 of Mn2+ (3d)5 ion by analyzing the excitation spectrum and electron spin resonance measurement. The emission at 650 nm is triggered by the band edge excitation and is assigned similarly to the charge-transfer process associated with the manganese ion

  7. Elucidating the pathway for arsenic methylation

    Although biomethylation of arsenic has been studied for more than a century, unequivocal demonstration of the methylation of inorganic arsenic by humans occurred only about 30 years ago. Because methylation of inorganic arsenic activates it to more reactive and toxic forms, elucidating the pathway for the methylation of this metalloid is a topic of considerable importance. Understanding arsenic metabolism is of public health concern as millions of people chronically consume drinking water that contains high concentrations of inorganic arsenic. Hence, the focus of our research has been to elucidate the molecular basis of the steps in the pathway that leads from inorganic arsenic to methylated and dimethylated arsenicals. Here we describe a new S-adenosylmethionine (AdoMet)-dependent methyltransferase from rat liver cytosol that catalyzes the conversion of arsenite to methylated and dimethylated species. This 42-kDa protein has sequence motifs common to many non-nucleic acid methyltransferases and is closely related to methyltransferases of previously unknown function that have been identified by conceptual translations of cyt19 genes of mouse and human genomes. Hence, we designate rat liver arsenic methyltransferase as cyt19 and suggest that orthologous cyt19 genes encode an arsenic methyltransferase in the mouse and human genomes. Our studies with recombinant rat cyt19 find that, in the presence of an exogenous or a physiological reductant, this protein can catalyze the entire sequence of reactions that convert arsenite to methylated metabolites. A scheme linking cyt19 and thioredoxin-thioredoxin reductase in the methylation and reduction of arsenicals is proposed

  8. Arsenic burden survey among refuse incinerator workers

    Chao Chung-Liang

    2005-01-01

    Full Text Available Background: Incinerator workers are not considered to have arsenic overexposure although they have the risk of overexposure to other heavy metals. Aim: To examine the relationship between arsenic burden and risk of occupational exposure in employees working at a municipal refuse incinerator by determining the concentrations of arsenic in the blood and urine. Settings and Design: The workers were divided into three groups based on their probability of contact with combustion-generated residues, namely Group 1: indirect contact, Group 2: direct contact and Group 3: no contact. Healthy age- and sex-matched residents living in the vicinity were enrolled as the control group. Materials and Methods: Heavy metal concentrations were measured by atomic absorption spectrophotometer. Downstream rivers and drinking water of the residents were examined for environmental arsenic pollution. A questionnaire survey concerning the contact history of arsenic was simultaneously conducted. Statistical analysis: Non-parametric tests, cross-tabulation and multinomial logistic regression. Results: This study recruited 122 incinerator workers. The urine and blood arsenic concentrations as well as incidences of overexposure were significantly higher in the workers than in control subjects. The workers who had indirect or no contact with combustion-generated residues had significantly higher blood arsenic level. Arsenic contact history could not explain the difference. Airborne and waterborne arsenic pollution were not detected. Conclusion: Incinerator workers run the risk of being exposed to arsenic pollution, especially those who have incomplete protection in the workplace even though they only have indirect or no contact with combustion-generated pollutants.

  9. Mechanistic and Synthetic Approaches for Activation of Water-and Oxygen-Species by Biomimetic Systems (Containing Manganese and Cobalt)

    Lieb, Dominik

    2013-01-01

    The current work deals with elementary reaction steps involved in the mechanisms that lead to the activation of water and oxygen species by biomimetic systems featuring redox-active manganese and cobalt centers, respectively. The first part of this work (Chapter 2 and Chapter 3) deals with the role of water exchange on metal centers that are relevant for water oxidation in nature. The first of two studies about this subject is addressing the role of manganese(III) in the oxygen evolving clust...

  10. Arsenic Geochemistry in Source Waters of the Los Angeles Aqueduct

    Hering, Janet G; Wilkie, Jennifer A; Chiu, Van Q

    1997-01-01

    Arsenic is a widely distributed constituent of geologic materials, with an average crustal abundance of 1.8 ppm. The natural processes of weathering of arsenic-containing minerals and volcanism contribute arsenic to groundwaters, surface freshwaters, and seawater. Recently, increased attention has focused on arsenic geochemistry in natural waters. This attention has been motivated by concern over the human health effects of arsenic exposure; consumption of drinking water can be a significant,...