PRESENT GROUNDWATER ARSENIC CONTAMINATION STATUS...

5TH International Conference on Arsenic Exposure and Health Effects

SPEAKERS' ABSTRACTS

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PRESENT GROUNDWATER ARSENIC CONTAMINATION STATUS INWEST BENGAL, INDIA

Dipankar Chakraborti, Ph.D., Mohammad Mahmudur Rahman, M.Sc., Uttam KumarChowdhury, Ph.D., Kunal Paul, M.Sc., Mrinal Sengupta, M.Sc., Dilip Lodh,PGDCA., Gautam Kumar Basu, Ph.D., Chitta Ranjan Chanda, Ph.D., KshitishChandra Saha, MD, Subhash Chandra Mukherjee, MD, School of EnvironmentalStudies, Jadavpur University

Arsenic contamination in groundwater and consequent human suffering in WestBengal, India was first reported in December 1983 when 63 arsenic patients from 3villages were identified. At present 3000 villages are arsenic affected. Even after 14years of our field survey we believe our study reflects only the tip of the iceberg inidentifying the extent of arsenic contamination. The area and population of these 9arsenic affected districts of West Bengal are 38865 km2 and 42.7 millionrespectively. Till to-date, we have analyzed by FI-HG-AAS 1,10,000 hand tube wellwater samples from 9 arsenic affected districts. Out of them, 51% are unsafe to drinkaccording to the WHO recommended value of arsenic in drinking water (10 µg/L).In our preliminary study, 95000 people were clinically examined from arsenicaffected districts of West Bengal and 10100 people (9.4% including 2% children)were registered with arsenical skin lesions. At least 100 cancer and few hundredssuspected Bowens disease were detected. Peripheral neuropathy is a commonfinding to those having arsenical skin lesions. We have analyzed around 35000biological samples collected from the arsenic affected villages and on average 85%of the samples contain arsenic above normal level. Thus many people in the affectedvillages may be sub-clinically affected. Children are more susceptible to arsenictoxicity. Approximately 90% of the children below 11 years, living in arsenicaffected villages show elevated level of arsenic in hair and nails. Infants and childrenmight be at greater risk from arsenic toxicity due to more water consumption on bodyweight basis. Villagers are using arsenic contaminated water not only for drinkingand cooking but also in agricultural field. Our study during last two years reveals thepresence of elevated level of inorganic arsenic in food chain and in those consumerproducts where groundwater is used in affected villages. To combat this deadlyarsenic menace we need to increase awareness and educate our villagers about theproblem and instead of reckless use of groundwater we should preferably utilize ourvast available surface water, rain water with people’s participation.

CORRESPONDING AUTHOR: Dipankar Chakraborti, Ph.D., School of EnvironmentalStudies, Jadavpur University, Kolkata- 700 032, India, Tel: 91 33 4735233, Fax: 9133 4734266, E-mail: [email protected]


SPEAKERS' ABSTRACTS

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ARSENIC CONTAMINATION IN GROUNDWATER AND DRINKINGWATER OF THE RED RIVER DELTA, VIETNAM – A PLEA FOR

EARLY MITIGATION ACTIONS

Michael Berg, Roland Schertenleib, Walter Giger, EAWAG Switzerland; HongCon Tran, Thi Chuyen Nguyen, Hung Viet Pham, Hanoi University of Science

Arsenic contaminated aquifers were discovered in late 1998 in the Red RiverDelta of northern Vietnam through a cooperative project between Vietnam andSwitzerland aiming at building environmental sciences capacity in Vietnam. Acomprehensive survey on arsenic in ground and drinking water of the city of Hanoi,and of the surrounding rural districts was conducted in 1999 and 2000.

The study revealed arsenic concentrations in the groundwaters ranging from1–3050 :g/L. Groundwater pumped through family-based tubewells contained a totalaverage of 159 :g/L arsenic. While 48% of the samples were above the Vietnameseguideline value of 50 :g/L, an alarming fraction of 20% were even above 150 :g/L.The tap water of Hanoi city, piped by the Hanoi water works, was less contaminated(25–91 :g/L). The situation in the Red River Delta will be presented and discussedconsidering the hydrogeological properties of both, natural and anthropogenicinfluences.

Our results indicate that several million people in the Red River Delta are at aconsiderable risk of chronic arsenic poisoning. Interestingly, arsenic related healthsymptoms have not been reported in Vietnam so far. We attribute this fact to the localwater use habits and the relatively short time of exposure of the people. The firsttubewells exploiting groundwater for direct consumption have been installed in thelast 6-8 years. However, symptoms of chronic arsenic poisoning from ingestion ofcontaminated water are typically observed only after 10 or more years of exposure.

To reduce the risk of chronic arsenic poisoning for people in Vietnam, weurgently propose early mitigation actions and further evaluation of the extent of theground and drinking water contamination by arsenic in the alluvial deltas of Vietnam.

CORRESPONDING AUTHOR: Michael Berg, Water Resources and DrinkingWater Dept, Swiss Federal Institute for Environmental Science and Technology(EAWAG), CH-8600 Duebendorf, Switzerland. [email protected], www.eawag.ch/~berg/arsenic, www.eawag.ch/arsenic


SPEAKERS' ABSTRACTS

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GROUNDWATER ARSENIC CONTAMINATION IN NEPAL:A NEW CHALLENGE FOR WATER SUPPLY SECTOR

Roshan R. Shrestha, Ph.D., Arinita Maskey B.Sc., Environment & Public HealthOrganization (ENPHO) and Padam K. Khadka MA., Nepal Red Cross Society

Groundwater is the major drinking water source for the Terai population of southern Nepalwhere 47% of total population of 23 million people lives. About 200,000 shallow tube-wells are installed in the 20 districts that comprise the Terai region serving about 11million people. Recently, arsenic contamination of the shallow groundwater aquifer hasbecome a big issue in Nepal., although it is not as severe as in Bangladesh and WestBengal. To date, water samples from about 13,000 tube-wells have been tested with 29%of samples exceeding the World Health Organization guideline of 10 ppb and 5% ofsamples exceeding the “Nepal Interim Arsenic Guideline” of 50 ppb. This gives anestimate of around 0.5 million people exposed to arsenic levels in drinking water above50 ppb. Some recent studies have reported on the accumulation of arsenic in the humanbody above toxic levels in arsenic-exposed areas. Government, national and internationalnon-governmental organizations are well aware of the situation now, but to date, thegovernment has not yet able to come up with concrete mitigation plans. Nepal still needsmore research work on arsenic occurrence and affects and, at the same time, a mitigationprogram should be conducted in parallel. This paper highlights the details of the arsenicstudies conducted thus far by different agencies and the pros and cons of the currentmeasures to mitigate the arsenic problem in Nepal.

CORRESPONDING AUTHOR: Roshan R. Shrestha Ph.D., Environment & Public HealthOrganization (ENPHO). P.O.Box 4102 Kathmandu Nepal. Fax : 977 1 491376. Email :[email protected]


SPEAKERS' ABSTRACTS

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ENVIRONMENTAL IMPACTS, EXPOSURE ASSESSMENT AND HEALTHEFFECTS RELATED TO ARSENIC EMISSIONS FROM A COAL-FIREDPOWER PLANT IN CENTRAL SLOVAKIA; THE EXPASCAN STUDY.

Thornton I., Farago M.E., Keegan T, Nieuwenhuijsen M. J., Pesch B., and theEXPASCAN study group.

The coal-fired power plant at Novaky in the Prievidza district of Central Slovakia hasemitted in excess of 3,000 tonnes As since commencing operations in the 1950’s. Thisresulted from the combustion of brown coal containing up to 1500:g/g As. Pollutioncontrol measures reduced emissions from around 200-2 tonnes per year in the 1980’s. Thispaper presents a) the results of environmental monitoring undertaken in 1999-2000, basedon the analysis of soils and dusts from 550 households comprising a population- basedcase-control study of non-melanoma skin cancer, b) data on As levels in coal currentlyused for power generation and in fly ash dumped within the district, c) estimates of Asexposure in the population in relation to distance from the plant, and d) a summary ofhealth statistics.

Although arsenic levels in soils and house dusts fell with distance from the plant, actualconcentrations were low with soils averaging around 40:g/g within 5km and 20-25:g/gover 5km from the plant, and dusts 18 and 11:g/g As respectively. Total urine arsenicconcentrations were low, averaging 6.4mg/g creatinine and showed a weak correlationwith soil arsenic.

Predictions of As deposition rates from air dispersion modelling (ADMS) based on currentand historical levels of air borne As indicated soil As concentrations considerably in excessof current levels. Possible losses due to leaching and biogeochemical cycling arediscussed together with the implications of these losses to human exposure.

Exposure to environmental arsenic in the study area was associated with an increased riskof non-melanoma skin cancer, as was distance to the source of the arsenic. Exposure toarsenic via locally grown food was associated, but not significantly, with increased riskof non-melanoma skin cancer.

Arsenic emissions were highest 20 years ago and current environmental levels might notreflect past exposure. The epidemiological exposure model included historical emissionsdata but past and present industrial emissions from other sources and lack of accurateexposure assessment of arsenic in the local diet could have confounded the distance- andfood-related exposure variables.


SPEAKERS' ABSTRACTS

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ASSESSING POTENTIAL ARSENIC EXPOSURE PATHWAYS INBANGLADESH

Ravi Naidu1, Imamul Huq2, Euan Smith1, Ray Correll3, Lester Smith1, Julie Smith1,Tapas Biswas1, the late Mushtaq Ahmed2, the late Shibtosh Roy4 and Mary Barnes3

1 CSIRO Land and Water, Waite Road, Urrbrae, Adelaide SA 5064,2 Department of Soil Science, Dhaka University, Dhaka, Bangladesh3 CSIRO Mathematical and Information Sciences, Waite Road, Urrbrae, Adelaide, SA50644 Dhaka Community Hospital, Dhaka, Bangladesh

Background

Since the first report on possible arsenic (As) poisoning of people in the Indiansubcontinent, many incidences of chronic As toxicity has been identified in a number ofcountries in the SE Asia region. Almost all of these cases have been related to theingestion of As-contaminated groundwater. The As concentrations in groundwaterexceed the Bangladesh recommended value of 0.05 mg L-1 in 52 of the 64 districts inBangladesh and 560 villages in West Bengal, India. (Note that the WHO standard is0.01 mg L-1 ). Given the lack of detailed studies on possible pathways of As exposure,it has been assumed that poisoning is through the consumption of water per se.However, the chronic As toxicity symptoms recorded indicate that the exposure to Asmay involve a number of pathways. Arsenic contaminated groundwater is used forirrigation as well as for cooking and it is likely that the last 30 years of irrigation haveled to diffuse contamination of land throughout the districts relying on As contaminatedgroundwater. This indicates that soil-crop-food transfer, as well as cooking and directingestion of drinking water may be the major exposure pathways of As transfer. Thispaper explores several pathways of inadvertent exposure including ingestion of food.Future studies are planned to investigate As exposure through ingestion of dust and soiland dermal absorption, especially in the Asian region where wetland farming is a majoractivity amongst the farming community. Only data on As content of food crops arepresented here.


SPEAKERS' ABSTRACTS

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CHILDREN’S EXPOSURE TO ARSENIC IN CHROMATED COPPERARSENATE (CCA)-TREATED WOOD AND CCA-CONTAMINATED SOIL

Tim F. McMahon, Ph.D., Doreen Aviado, B.S., Winston Dang, Ph.D., SiroosMostaghimi, Ph.D., Jonathan Chen, Ph.D. U.S. Environmental Protection Agency,Office of Pesticide Programs, Washington D.C.

The Office of Pesticide Programs (OPP) is aware of increased concerns by thepublic regarding the safety of CCA-treated wood and children’s exposure to thearsenic component of this wood. Therefore, an exposure assessment is currentlybeing conducted by the Antimicrobials Division (AD), OPP, to determine potentialnon-dietary exposures of children that may occur from contact with CCA-treatedwood playground structures and CCA-contaminated soils. Dermal and oral exposuremay occur from contact with dislodgeable surface residues of arsenic as well as withcontaminated soil. As part of the development of this assessment, specific exposuredata issues were presented by AD scientists to the FIFRA Scientific Advisory Panel(SAP) in October of 2001 for discussion. The SAP provided recommendations toAD in several areas of the exposure assessment. The most significant of these was the recommendation to use probabilistic exposure modeling for assessment ofchildren’s exposures. AD is now in the process of implementing this approach toassessment of children’s exposure to arsenic from CCA-treated wood, and hopes touse the results of this approach, when available, in the risk assessment for CCA-treated wood.

CORRESPONDING AUTHOR: Tim F. McMahon, Ph.D. , U.S. EnvironmentalProtection Agency, Office of Pesticide Programs, 1200 Pennsylvania Ave. N.W.,Ariel Rios Building, Mail Code 7510C, Washington, D.C. 20460


SPEAKERS' ABSTRACTS

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TRIVALENT ARSENIC COMPOUNDS: SPECIATION, PRESERVATION,AND INTERACTION WITH PROTEINS

X. Chris Le, Ph.D., Zhilong Gong, Ph.D., Guifeng Jiang, Ph.D., Xiufen Lu, M.Sc.,University of AlbertaWilliam R. Cullen, Ph.D., University of British Columbia

Trivalent arsenic compounds, including arsenite (AsIII), monomethylarsonousacid (MMAIII), and dimethylarsinous acid (DMAIII), are now known to be more toxicthan their pentavalent counterparts, namely arsenate (AsV), monomethylarsonic acid(MMAV), and dimethylarsinic acid (DMAV). We describe the speciation analysis ofthese trivalent arsenic compounds in biological systems and examination ofinteractions between trivalent arsenic species with proteins.

The speciation analysis of arsenic was carried out by using high performanceliquid chromatography (HPLC) separation with hydride generation atomicfluorescence detection (HGAFS). MMAIII and DMAIII were found to be unstable inurine samples and therefore a method for preserving these arsenic species wasdeveloped. Several complexing agents were tested as additives to preserve MMAIII

and DMAIII in human urine samples. Diethylammonium diethyldithiocarbamate(DDDC) was found to be most suitable for this purpose.

Both inductively coupled plasma mass spectrometry (ICPMS) andelectrospray quadrupole time-of-flight mass spectrometry (Q-TOF MS) were used tostudy the binding between a model protein metallothionein and various arseniccompounds. Size exclusion chromatography with ICPMS analysis of reactionmixtures between trivalent arsenic compounds and metallothionein demonstrated theformation of complexes of arsenic with metallothionein. Analysis of the complexesusing Q-TOF tandem mass spectrometry revealed the detailed binding stoichiometrybetween arsenic and the 20 thiol groups in the metallothionein molecule. AsIII and twomethylation metabolites, MMAIII and DMAIII, showed different binding stoichiometrywith the metallothionein. Each metallothionein molecule could bind with up to 6AsIII, 10 MMAIII, and 20 DMAIII molecules, consistent with the available binding siteson these arsenicals. Tandem mass spectrometry detection of the fragment ions fromthe intact protein provided further evidence for the As-S bond formation in thearsenic-metallothionein complex.

CORRESPONDING AUTHOR: X. Chris Le, Ph.D., Department of Public Health Sciences, Faculty ofMedicine, University of Alberta, 10-102 CSB, Edmonton, Alberta, Canada T6G 2G3


SPEAKERS' ABSTRACTS

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ARSENIC SPECIATION IN PROBLEMATIC SEAFOOD MATRICES: THE IMPORTANCE OF A SPECIES SPECIFIC MASS BALANCE

John T. Creed, Ph.D., Patricia A. Gallagher, Ph.D., Jody Shoemaker, Ph.D., Carol A., Schwegel, US EPA; Bryan M. Gamble, Ph.D., Amy N. Parks, OakridgeResearch Fellows

Arsenic has two major exposure routes: dietary and drinking wateringestion. Dietary exposures can easily exceed those typically associated withdrinking water but the risk associated with these exposures are strongly influencedby the toxicity of the arsenicals present in the sample. For instance, a majorsource of dietary arsenic is seafood but 90+% of the “extractable” arsenicals canbe non-toxic; therefore, species specific information is essential in estimating therisk associated with dietary exposures. A source of uncertainty associated withestimating dietary risks is the limited availability of species specific data on targetfoods.

One of the analytical problems associated with arsenic speciation (speciesspecific detection) in dietary samples is the need to extract the arsenicals from thesolid dietary matrix. In many cases, the predominant “extractable” arsenicalassociated with seafood has been non-toxic arsenobetaine, but in certain seafoodmatrices the “extractable” arsenicals may be less than 50% of the total arsenic. This raises questions about the toxicity of the “unextractable” arsenicals and thepotential for underestimating the risk (i.e., exposure) based on this analyticalextraction bias. These low extraction efficiencies can be further complicated byunchromatographable arsenicals. The net result is the unextractable andunchromatographable fraction sequentially decrease the available speciationinformation.

This presentation will focus on the use of tetramethylammoniumhydroxide as an extraction solvent in seafood samples collected in the PacificNorthwest (clams, mussels, and oysters). This presentation will address theconversion of unchromatographable species to chromatographable arsenosugarsand how this influences the overall speciation recovery and in turn the ability toassess the risk from these matices.

CORRESPONDING AUTHOR: John T. Creed, Ph.D., US EPA, Mail Stop 564,26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA.


SPEAKERS' ABSTRACTS

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ARSENIC IN YELLOWKNIFE, CANADA

William. R. Cullen, Ph.D., Lixia Wang, B.Sc., Vivian W.-M. Lai, M.Sc., ElenaPolishchuk, Ph.D., Environmental Chemistry Group, University of British Columbia;Iris Koch, Ph.D., Christopher A. Ollson, M.Sc., Kenneth J. Reimer, Ph.D.,Environmental Sciences Group, Royal Military College of Canada

The arsenic levels in soil from the City of Yellowknife, Canada, range from4 ppm to 148 ppm and at some mine sites from 2125 ppm to 87,000 ppm. In suchan arsenic rich environment there are problems in determining what are the natural,pre-mining, concentrations that could be considered to be a remediation objective.We have applied principal component analysis (PCA) to this problem and concludethat the background arsenic concentrations are in the range 3 ppm to 150 ppm withan average value of 42 ppm, far higher that the Canadian guideline of 12 ppm.

About 260,000 tones of arsenic trioxide (ca. 80% pure) are storedunderground in old mine workings and in specially constructed vaults. The optionsfor safe management of this material will be discussed. Some promising results arebeing obtained from mine-dust/bitumen materials. Many fungi such as Aleurodiscusfarlowii grow underground: these are being isolated and identified by using 28SRNA analysis. We are studying how they prosper in such an arsenic–richenvironment. Sequential extraction and gastric fluid models are being developed todetermine the bioavailability of arsenic from local soils, vegetables, and countryfood.

CORRESPONDING AUTHOR: William R. Cullen, Ph.D., EnvironmentalChemistry Group, Chemistry Department, University of British Columbia,Vancouver, B. C., Canada, V6T 1Z1.


SPEAKERS' ABSTRACTS

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POTENTIAL FOR ADVERSE EFFECTS OF SOIL AS

Rufus L. Chaney, USDA-ARS, Animal Manure and Byproducts Lab, Bldg. 007,BARC-West, Beltsville, MD. 20705-2350. USA.

As is a natural constituent of soils and plants. The low soil As limit suggestedby some (3.0 mg As/kg soil) is below natural background levels in US soils; thusvalidity of such limits is being questioned. Background As levels in US soils are5-10 mg/kg, with range exceeding 20 mg/kg for acid sulfate soils; background Asexceeds suggested soil As limits. Extensive contamination of soils with As byhistoric agricultural uses (orchard, cotton, and potato soils; tick treatment soils),mining, smelting, and the extensive use of Cr-Cu-As-treated lumber, indicate thatover 50% of US surface soils would need to be replaced. It seems irrational toconclude that median background soils are causing human As risk thru soilingestion.

Rice accumulates As well compared to most plant foods. Rice accumulationof As from soils irrigated with As-rich water over decades was not increased ineither As-sensitive or -resistant rice cultivars in a collaborative field test inBulgaria indicating lower potential food-chain As risk than some suggest.

Soil ingestion comprises greater risk than eating garden foods. Theassumptions in soil As risk assessment are known to be faulty; one assumes thatchildren consume soil at the rate of a 2-year-old child for one’s lifetime;adjustment of risk estimates is needed for short term exposure of children by soilingestion. Raised urinary As in children exposed to As in soil and dust found thatsoil As had to exceed 40-100 mg As/kg before there was a significant increase inurinary As from inorganic sources, suggesting that soil As would have to exceedthis level before any increase in absorbed As would occur.


SPEAKERS' ABSTRACTS

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ARSENIC MOBILIZATION IN BANGLADESH GROUNDWATER

Y. Zheng, Ph.D., R. K. Dhar, Queens College and Lamont-Doherty EarthObservatory of Columbia University, M. Stute, Ph.D., A. van Geen Ph.D., A.Horneman, LDEO, I. Gavrieli, Ph.D., Israeli Geological Survey, S. Goodbred,Ph.D., Stony Brook University, R. Versteeg, Ph.D., M. Steckler, Ph.D., H. J.Simpson, Ph.D., Z. Cheng, Ph.D., LDEO, K. M. Ahmed, Ph.D., M.Shamsudduha, and M. Shahnewaz, Dhaka University.

In the Ganges-Brahmaputra Delta, concentrations of arsenic in groundwater canvary from < 5 mg/L to > 1000 mg/L within lateral and vertical scales of tens ofmeters. The main objectives of our study are to understand the factors that contributeto such spatial variability of arsenic at the local scale (# 1 km) and to investigate anypotential temporal variability of groundwater arsenic concentrations in order toillustrate the origin of As.

Multi-disciplinary investigation to date has focused on several villages within a20-km2 region in Araihazar Upazila, about 20 km east of Dhaka. Extreme spatialvariability of arsenic concentrations (< 5 to ~ 800 mg/L) is observed in the shallow,presumed Holocene sedimentary aquifers. A suite of redox-indicators measured inparallel with arsenic indicate that As mobilization generally follows the reduction ofFe-oxyhyroxides, and, in some cases, even extends into sulfate-reducing state.Drilling at several locations identified clay formations of various thickness at variousdepth interval that separates the shallow, As-containing aquifer from the deep, lowAs aquifer that is chemically distinct. Despite the extensive spatial variability, weobserved little temporal variability of arsenic concentrations in both the shallow andthe deep aquifers. Only one of ~ 50 shallow groundwater wells (< 50 ft) in a villagethat were sampled in March-June 2001, January, June and September 2001 showeda difference of As concentration greater than the analytical uncertainty. Monitoringwells installed at various depths were sampled at monthly interval and showed littlevariation of arsenic concentrations throughout 2001.

CORRESPONDING AUTHOR: Yan Zheng, Ph.D., Queens College, CityUniversity of New York, Flushing, NY 11367 and Lamont-Doherty EarthObservatory of Columbia University, Palisades, NY 10964.


SPEAKERS' ABSTRACTS

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A LONG-TERM FOLLOW-UP STUDY ON DOSE-RESPONSERELATIONSHIP BETWEEN INGESTED ARSENIC AND MAJOR

CANCERS AND VASCULAR DISEASES IN TAIWAN Chien-Jen Chen, Sc.D., Chi-Ling Chen, Ph.D., Chih-Hao Wang, M.D., Lin-I Hsu,Ph.D., Chin-Hsiao Tseng, Ph.D., National Taiwan University; Hung-Yi Chiou,Ph.D., Yu-Mei Hsueh, Ph.D., Taipei Medical University; Shu-Yuan Chen, Ph.D.,National Health Research Institutes; Meei-Mann Wu, Ph.D., Academia Sinica

We have recently documented the biological gradient between ingested arsenicand risk of various cancers, peripheral vascular disease, ischemic heart disease,cerebral infarction, microcirculation retardation, diabetes mellitus and hypertensionthrough ecological, cross-sectional or case-control studies. The specific aim of thisstudy is to follow-up three cohorts of study subjects in arseniasis-endemic and non-endemic areas to compare their risk of major cancers and vascular diseases. The firstcohort included 2,905 residents in the southwestern arseniasis-endemic area recruitedfrom1984 to 1992. The second cohort included 8,102 residents in the northeasternarseniasis-endemic area recruited from 1994 to 1996. The third cohort included23,943 resident in seven non-arseniasis-endemic townships recruited from 1991 to1992. History of exposures to ingested arsenic and various risk factors was obtainedthrough standardized questionnaire interview. The occurrence of major cancers andvascular diseases of cohort members was ascertained by home visit/telephoneinterview and double-check with medical chart review and by data linkage withNational Death Certification and National Cancer Registry profiles. Coxproportional hazards regression analysis was used to assess the relative risk ofdeveloping major diseases and its 95% confidence interval for each risk factor.Residents in arseniasis-endemic areas had a significantly higher risk of major cancersand vascular diseases than residents in non-endemic areas. There was a significantdose-response relationship between major cancers and vascular diseases and ingested

arsenic at levels ranging from <10 to >700:g/L, with a clearly increased risk at the

level of 10-50:g/L.

CORRESPONDING AUTHOR: Chien-Jen Chen, Sc.D., Graduate Institute ofEpidemiology, College of Public Health, National Taiwan University, 1 Jen-Ai RoadSection 1, Taipei 10018, TAIWAN.


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EXPOSURE TO ARSENIC IN DRINKING WATER DURINGPREGNANCY

Claudia Hopenhayn, M.P.H., Ph.D., Bin Huang, M.S., Steven R. Browning, Ph.D.,Cecilia Peralta, University of Kentucky, USA; Catterina Ferreccio, M.D., M.P.H.,Pontificia Universidad Católica de Chile; Irva Hertz-Picciotto, M.P.H., Ph.D.,University of California, Davis, USA; Herman Gibb, Ph.D., EnvironmentalProtection Agency, USA; Jose Centeno, Ph.D., American Registry of Pathology,Armed Forces Institute of Pathology, U.S.A.

The current evidence indicates that arsenic increases the risk of variouscancers, and is also associated with non-cancer health effects such as diabetes,hypertension and other cardiovascular events. Although limited, the existingevidence also suggests that arsenic may have adverse reproductive effects in humans.The purpose of this study is to investigate pregnancy and birth outcomes in relationto arsenic exposure from drinking water.

We conducted a prospective cohort study, enrolling pregnant women in twoChilean cities: 454 in Antofagasta (arsenic water level of 40 ug/L), and 468 inValparaíso (As level <1 ug/L). Study subjects completed in-depth interviews,providing information on demographics characteristics, medical and reproductivehistory, diet, fluid intake, lifestyle habits, and other factors. We obtained pregnancyand birth related data from prenatal and hospital records. All births took place from12/29/98 to 3/19/00. Biological samples including urine, placenta and cord bloodwere obtained for different sub-groups of the cohort. We also used the PerinatalInformation System (SIP) from the Pan-American Health Organization to collect adetailed database of all births occurring at each city’s main hospital, from July, 1999to July, 2000, totaling over 8,000 births.

We will present the overall results of the study, focusing the analysis onbirthweight from both the cohort and the SIP data, which show consistent and similarresults, with an overall decrease in mean birthweight of about 50 grams in thearsenic-exposed city after controlling for relevant covariates. We will also presentresults of the analysis of biological samples, currently being completed.

Corresponding author: Claudia Hopenhayn, M.P.H., Ph.D., Department of PreventiveMedicine and Environmental Health, University of Kentucky, 1141 Red Mile Road,Suite 201, Lexington, KY 40504.


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CRITERIA FOR CASE DEFINITION OF ARSENICOSIS

DN Guha Mazumder, MD., FAMS

Institute of Post Graduate Medical Education & Research, Kolkata, India

In spite of availability of large number of publications based on studies on healthaspect of chronic As toxicity, no standard definition is available to characterize fullythe clinical effects of chronic As exposure in man. Only small number of reports arebased on validation of diagnosis on proper As exposure data, blinding of cases andcontrols, total assessment of clinical effect, and correlation of these effects with Aslevel in water, and various biomarkers. It was therefore felt necessary to prepare aclinical case definition of chronic arsenicosis.

Thirty six papers on As related health effects were reviewed directly and numerouscross references consulted. Giving weightage on the quality of these papers,diagnostic criteria of chronic arsenicosis have been prepared.

On the basis of review of literature, a minimum period of six months of ingestion ofAs have been considered for the diagnosis of arsenicosis. Normal As values of urine,hair and nails determined by proper techniques, e.g. AAS or NAA have also beenreviewed. Mean +2SD of the normal values of the acceptable published reports havebeen calculated. From these the upper limit of normal As level in urine, hair and nailwas considered to be as 0.05 mg/l, 0.8 mg/kg and 1.3 mg/kg, respectively.

Skin lesions, simulating arsenical dermatosis, but caused by other systemic or skindiseases simulating As induced skin lesion have been reviewed. These conditionsneed to be considered in the differential diagnosis of arsenicosis. Over and aboveskin lesions, criteria related to systemic manifestation and various As related cancerswere also considered for the preparation of case definition of chronic Arsenicosis. Asimplified algorithm of case definition, using dermatological criteria as major clinicaldiagnostic parameter, has been prepared and will be presented in the conference.

Corresponding Author : Dr. DN Guha Mazumder, Instt. Post. Grad. Med. Edu. &Res., 244, AJC Bose Road, Kolkata – 700 020. India. Email- [email protected]


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A COHORT STUDY OF HEALTH EFFECTS OF ARSENIC EXPOSUREIN BANGLADESH: PROGRESS AND PRELIMINARY FINDINGS

Habibul Ahsan, M.D., M.Med.Sc., Faruque Parvez, M.P.H., Columbia University;A.Z.M. Iftikhar Hussain, M.B.B.S., M.P.H., Hassina Momotaj, M.B.B.S., M.P.H.,National Institute of Social and Preventive Medicine (NIPSOM); Yu Chen,M.P.H., Geoffrey Howe, Ph.D., Wei-Yan Tsai, Ph.D., Regina Santella, Ph.D.,Paul Brandt-Rauf, M.D., Ph.D., Jack Longley, M.D., Alexander van-Geen, Ph.D.,and Joseph Graziano, Ph.D., Columbia University.

We are conducting a large epidemiologic cohort study of 10,000 men andwomen to comprehensively examine prospectively the health effects of arsenicexposure in Bangladesh with an initial emphasis on the full dose-responserelationships of arsenic exposure with the incidence rates of skin lesions, skincancers, and total and cancer-related mortalities. In addition, using cross-sectionaland case-cohort designs within the main cohort, the interrelationships amongurinary arsenic metabolites, a number of biomarkers and health outcomes are alsobeing examined.

To build a sampling frame for the cohort study, 6,000 tube-wells in acontiguous area were surveyed and analyzed enumerating and characterizing60,000 residents. Using predetermined sampling criteria, 10,000 men and women(from the 60,000 residents) were recruited in the cohort. Extensive interview,clinical data, and biological samples have been collected from the cohortmembers. The cohort members are being actively followed to ascertain the studyoutcomes. Overall, data from this comprehensive study will provide informationon the interrelationships between arsenic doses, intermediate biomarkers, andother host and lifestyle factors including the genetics and nutrition in the etiologyof arsenic-induced cancers and other health outcomes. Design and progress ofthis comprehensive epidemiologic study, preliminary baseline data, and apreliminary analysis of cancer burden in Bangladesh based on the baseline datawill be presented.

CORRESPONDING AUTHOR: Habibul Ahsan, M.D., Med.Sc., Department of Epidemiology, Columbia University, 600 West 168th Street, PH 18, New York, NY 10032


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RELATIONS OF URINARY TRIVALENT METHYLATED ARSENICSPECIES WITH ARSENIC-SKIN LESIONS AND URINE CYTOLOGY INPOPULATION CHRONICALLY EXPOSED TO INORGANIC ARSENIC.

Olga L. Valenzuela BSc, Luz M Del Razo Ph D Toxicology Section,CINVESTAV-IPN, México. Jesús Aguirre BSc, Hospital General de México,Martha B Cruz BSc, Diana Lechuga MSc. and Betzabet Calderon BSc,Secretaria de Salud de Hidalgo, México.

Biomethylation is the major metabolic process for inorganic As in humans.Inorganic As undergoes metabolic conversion that include reduction of pentavalentarsenicals to trivalency and oxidative methylation of trivalent species that yields tomethylarsenic (MAs) and dimethylarsenic (DMAs) species. Thus, both pentavalentand trivalent arsenicals are intermediates or final products of this pathway that canbe found in human urine. Due to increased recognition of the role of methylatedarsenicals that contain AsIII in the toxicity and metabolism of As, our objective wasto study the relationship of trivalent methylated metabolites with toxicity signs inhumans chronically exposed to As.

Some habitants of Zimapan area located in Hidalgo state, Mexico (about 220km north-east of Mexico City), have been exposed to very high levels of arsenic (As)in drinking water (150 to 1,350 ppb) at least from 1993. The highest ground waterAs concentrations appear to come from dissolution of the As bearing rocks. InZimapan area, many people present characteristic skin lesions related with chronicAs exposure, such as keratosis, hyperpigmentation and hypopigmentation.

A group of 104 exposed residents from endemic As-area of Zimapan wereasked to answer a questionnaire and allow to be physically examined. 51 participantsdisplayed severe skin injuries, 24 presented discreet dermal injuries and 29 did notpresented skin lesions. Collected spot urine samples were frozen in dry ice andtrivalent As species were analyzed approximately four hrs after collection,additionally exfoliated bladder cells were obtain from urine samples for cytologyanalysis. Trivalent methylated arsenic species were present in almost all the urinesamples (96 %), being DMAIII the major trivalent metabolite. The relationshipbetween trivalent arsenic species in urine and frequency of transformed epithelialbladder cells will be investigate.

Characterization of the urinary excretion of arsenicals that contain AsIII mayprovide a new biomarker of the effects of chronic exposure to As.Supported by Conacyt-Mexico 38471-M

CORRESPONDING AUTHOR: Luz M. Del Razo, Ph.D. Toxicologia,CINVESTAV-IPN, P.O.Box 14-740, Mexico D.F., email:[email protected]


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THE DISTRIBUTION OF ARSENIC CONCENTRATION IN WATER OFCHINA AND THE RELATION TO PATIENTS

Guifan Sun, Ph.D., China Medical University; Yang Hao, Ph.D., Division ofEndemic and Parasitic Diseases Control, Department of Diseases Control,Ministry of Health, China; Quanmei Zheng, Prof., China Medical University;Jihong Yin, Prof., Renmin University of China; Hiroshi Yamauchi, Ph.D., Schoolof Medicine, St. Marianna University, Japan

From 2001, we had been carrying out a nationwide survey of arsenicosis inChina. Besides the known epidemic areas, i.e. Xinjiang, Inner Mongolia, Shanxiand Guizhou, new areas have been found in Jinlin, Ningxia and Qinghaiprovinces. In order to obtain further information about the distribution of arsenicconcentration in water of China, two severe epidemic areas, i.e. Shanxi provinceand Inner Mongolia were selected as the investigation bases. Arsenicconcentration in water were measured by field-test kit purchased from MerkCompany of Germany. Epidemiological investigations were carried outmeanwhile. 35 villages of Shanxi province were investigated. 1612 out of total 3079 wells

were unsafe (arsenic concentration was above 0.05mg/L), with the ratio of 52 per

cent. Among the 9656 examined persons, 1561 were found to be patients. The

examination rate and prevalence rate among the examined persons were 53 and 16

per cent, respectively. 5885 wells of 64 villages were detected in Inner Mongolia.

Wells of arsenic concentration between 0.05~0.1, 0.1~0.5, and above 0.5mg/L

were 396, 267 and 2, respectively. 665 out of total 5885 wells were unsafe, with

the ratio of 11 per cent.

The investigation base of Shanxi was selected from the areas that had not

undertaken water mitigation, and occupied only a very small fraction compared

with the capacious epidemic areas. Therefore, large-scale investigation should be

needed so as to find new areas. As regard Inner Mongolia, the base was selected

from near the known epidemic areas, and was not officially considered to be areas

of arsenicosis. It can be concluded that the epidemic areas tend to expand

gradually now. Water samples are detected for the concentration of fluoride and

iodin in lab now.


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RISK ANALYSIS OF NON-MELANOMA SKIN CANCER INCIDENCE IN ARSENIC EXPOSED POPULATION

Vladimír Bencko, M.D., Ph.D., JiÍí Rameš, D.Sc., Charles University of Prague,Czech Republic; Miloslav Götzl, M.D., Department of Oncology District Hospitalof Bojnice, Slovak Republic; Petr Fran�k, EuroMISE Centre, Charles Universityof Prague & Czech Academy of Sciences, Czech Republic; Marián Jakubis, StateInstitute of Health, Prievidza, Slovak Republic

The subject of our analysis was a database of 1024 nonmelanoma skincancer cases collected within 20 years (4 five year intervals) in a region pollutedby emissions from burning of coal with high arsenic content ranging between 900to 1,500 g per metric ton of dry coal. The standardized incidence of nonmelanomaskin cancer (each confirmed by biopsy or autopsy histological examination) in adistrict with population ~125,000 in non-occupational settings ranged from 45.9to 93.9 in men and from 34.6 to 81.4 in women per 100,000 (study base 1,328thousands man/year and 1,334 thousands woman/year) while relevant data foroccupational settings (male workers of power plant burning arsenic reach coal)ranged from 44.6 to 10 317 per 100,000 (study base 27 thousands man/year).Smoking habit was carefully registered in all cancer patients including non-melanoma skin cancer cases and potential contribution of the both factors wasanalyzed. Exposure assessment was based on biological monitoring.Determination of arsenic was done in groups of 10 year old boys (in non –occupational settings) by analyzing of hair and urine samples at different localitiessituated up to the distances of 30 km from the local power plant.

Analysis of our database demonstrates a positive correlation of humancumulative arsenic exposure and incidence of non-melanoma skin cancer. Key words: cancer epidemiology, biological monitoring, arsenic toxicity, and non-melanoma skin cancer incidence Acknowledgement: The presented data resulted from EC supported INCOCOPERNICUS EXPASCAN project .

CORRESPONDING AUTHOR: Prof. Vladimír Bencko, M.D., Ph.D., Institute ofHygiene & Epidemiology, First School of Medicine, Charles University of Prague,Studni�kova 7, CZ 128 00 Praha 2, Czech Republic.


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U.S. Arsenic Exposure Data

Floyd J. Frost, Ph.D.Center for Pharmacoeconomic and Outcomes ResearchLovelace Respiratory Research Institute2425 Ridgecrest Dr. SEAlbuquerque, NM 87108

This report summarizes the completeness and accuracy of drinking water arsenicoccurrence data in the United States and to identify arsenic-exposed populationssuitable for epidemiological studies of arsenic health effects. Using data from theU.S. E.P.A. Arsenic Occurrence and Exposure Database, data we obtained fromstate health or environment departments, and data we obtained directly from waterutilities, we identified 33 counties in 11 states with a mean drinking water arsenicconcentration greater that 10 parts per billion (ppb). Eleven counties had a meanarsenic concentration greater than 20 ppb, and 2 counties had a mean arsenicconcentrations greater than 50 ppb. Between 1950 and 1999 there were 51million person-years of exposure to drinking water with more than 10 ppb arsenic,8.2 million to more than 20 ppb arsenic and 0.9 million to more than 50 ppbarsenic. Death rates in these counties from potentially arsenic-related causesshould be examined as part of a comprehensive assessment of arsenic healtheffects in U.S. populations.


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EXAMINATION OF THE NRC BLADDER CANCER RISK FROM ARSENIC INDRINKING WATER ESTIMATE, USING US DATA WITH 75 MILLION

PERSON-YEARS OF OBSERVATIONSteven H. Lamm, Arnold Engel, Richard Wilson, and Manning FeinleibConsultants in Epidemiology and Occupational Health, Inc.Harvard University Department of PhysicsJohns Hopkins School of Public Health

The NRC (2000) estimate for bladder cancer risk from arsenic in drinking water isbased on the data from the Blackfoot Disease Endemic area of SW Taiwan where increasedrisks of bladder cancer mortality were found in villages with 400 (+) ug/l arsenic in theirdrinking water. Those data have been adjusted and analyzed in order to predict the arsenicin drinking water bladder cancer risk in the United States where drinking water arseniclevels may go as high as 50 ug/l but are generally in the 3-12 ug/l or lower range. We nowpresent US data on bladder cancer mortality (1950-1979) in 133 US counties known todepend on ground water as their drinking water source (per state departments of theenvironment) and with ground water median arsenic concentrations of 3 ug/l or greater (USGeological Survey). The bladder cancer mortality for these 133 US counties, whichincludes a population of 2.5 million white males (1960 census), has been observed for 30years (1950-1979) by the National Cancer Institute for a total observation of 75 millionperson-years of observation.

Overall, the lifetime risk of bladder cancer mortality for white males is seen to be 0.005(1/200) and no increase with increased level of arsenic in the drinking water is observed.Linear regression shows a slope indistinguishable from zero, revealing no evidence of anarsenic-dependent risk in this exposure range. The R-squared is 0.0002, and the slope(lifetime increased risk per 1 ug/L arsenic exposure) is –4 E-06 with 95 % confidence limitsof –5 E-05 to+4.2 E-05. The NRC predicted risk of 4.6 E-05, based on extrapolation andadjustment from the southwest Taiwan data, is outside of the range that is consistent withthe US experience shown here in the 75 million person-year study. New toxicologicalstudies provide explanations as to why the increased bladder cancer risk from certainvillages in SW Taiwan is not predictive of the US experience with arsenic in the drinkingwater and bladder cancer mortality.


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ARSENIC CONCENTRATIONS IN WELL WATER AND RISK OF SKINCANCER IN WISCONSIN’S FOX RIVER VALLEY

Lynda M. Knobeloch, Ph.D., Henry A. Anderson M.D., and Lawrence P.Hanrahan, Ph.D. Wisconsin Department of Health and Family Services.

In 1987, elevated arsenic levels were discovered in several privatedrinking water wells located in Wisconsin’s Fox River Valley. A follow-upinvestigation identified a large vein of arsenic-bearing mineral deposits at theinterface of the St. Peter Sandstone and Sinnipee Dolomite. This formationstretches more than 100 miles and threatens more than 20,000 private watersupplies. Nearly 2,000 wells were sampled between 1992 and 1993. Concentrations ranged from below detection to 12,000 :g/L, and exceeded thenew federal standard of 10 ug/L in 20 percent of the wells.

Since June 2000, 18 townships in this area have sponsored voluntary watertesting programs for their residents. As part of these programs, water use andhealth history questionnaires were distributed along with water collection kits tofamilies that participated in the arsenic testing. More than 2,000 familiescompleted these providing arsenic exposure and health outcome information fornearly 7,000 individuals. Residents who ingested water that contained more than5 ug of arsenic per liter for 10 years or longer were more likely to report adiagnosis of skin cancer than others. Residents over the age of 64 years whoreported both a history of cigarette use and long-term exposure to arsenic-contaminated water had the highest skin cancer rate.

CORRESPONDING AUTHOR: Lynda M. Knobeloch, Ph.D., Department ofHealth and Family Services, 1 West Wilson St, Rm 150, Madison, WI 53701,USA.


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42

HEALTH EFFECTS OF CHRONIC EXPOSURE TO ARSENIC VIADRINKING WATER IN INNER MONGOLIA: I. BIOMARKERS FOR

ASSESSING EXPOSURE AND EFFECTS

Judy L. Mumford, Ph.D., Mike Schmitt, M.S.P.H., Richard K. Kwok, M.S.P.H.,Rebecca Calderon, Ph.D., National Health and Environmental Effects ResearchLaboratory, U.S. Environmental Protection Agency; Yajuan Xia, M.D. Ke KongWu, M.D., Inner Mongolia Center for Endemic Disease Control and Research,Kuan Yang, Li He Anti-epidemic Station, X. Chris Le, University of Alberta,Tong-cun Zhang, National Research Council

The residents of Ba Men, Inner Mongolia have been exposed to highconcentrations of arsenic via drinking water and showed health effects. Weconducted studies to assess health effects of arsenic, including dermal, DNA andchromosome damage, in Ba Men and to identify biomarkers useful for assessingarsenic exposure and health effects. A total of 321 Ba Men residents, exposed to low(<21 µg/L), medium (100-300 µg/L), or high (450-690 µg/L) concentrations ofarsenic were examined for the presence of skin hyperkeratosis, hyperpigmentationor depigmentation. Samples of well water, toenail, and urine were collected andanalyzed for arsenic content. Buccal cells were collected and assayed for DNAfragmentation (by TUNEL assay) and micronuclei to assess chromosome damage.Results showed that skin hyperkeratosis and alterations in skin pigmentation werehighly associated with arsenic concentrations in water, nails and urine (p<0.001).Increased micronucleus frequency and DNA fragmentation in buccal cells wereassociated with arsenic concentrations in water and nails (p<0.01). In urine, thepercent of methylated arsenicals in relation to total urinary arsenic was decreased(83% for low dose group to 79% for high dose group) as the arsenic concentrationin drinking water increased, suggesting limiting capacity for methylation in humans.Nail arsenic was a better exposure biomarker than urinary arsenic for assessingchronic health effects. This study showed that exposure to arsenic was associatedwith dermal effects as well as DNA and chromosome damage. These biomarkers arepotentially useful in early detection of health effects from chronic exposure toarsenic.

CORRESPONDING AUTHOR: Judy L. Mumford, Ph.D. Human StudiesDivision, National Health and Environmental Effects Research Laboratory, U.S.Environmental Protection Agency; Research Triangle Park, NC 27711, U.S.A.

(This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.)


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43

HEALTH EFFECTS OF CHRONIC EXPOSURE TO ARSENIC INDRINKING WATER IN INNER MONGOLIA: II. VIBROTACTILE AND

VISUAL MEASURES

David Otto, Ph.D., Judy Mumford, Ph.D., Richard K. Kwok, M.S.P.H., KenHudnell, Ph.D., U.S. Environmental Protection Agency; Yanhong Li, M.D.,Yajuan Xia, M.D. and Kegong Wu, M.D., Inner Mongolia Center for EndemicDisease Control and Research; Ling Ling He, B.S., BaMen Anti-epidemic Station,Biaxiao Zhao, B.S., Lin He Anti-epidemic Station

Exposure to arsenic via inhalation, oral or dermal pathways is known toproduce peri-pheral neuropathy in humans. A variety of neurotoxic symptomsincluding auditory, visual and somatosensory were reported (Ma et al, 1995) inMongolian farmers living in the Yellow River Valley (YRV) where the drinkingwater is contaminated by arsenic. In the present study, a brief sensory batteryincluding tests of visual acuity, contrast sensitivity, color discrimination(Lanthony D-15) and tactile sensitivity was administered to 321 YRV residents. Tactile thresholds in the 2nd and 5th fingers of both hands were assessed using abiothesiometer and as-cending method of limits. Participants were divided into 3exposure groups: low (<21 ug/L); medium (100-300 ug/L) and high (400-700ug/L) arsenic in well water. Three measures of As exposure were obtained: water,urinary and toe nail. Results indicate significantly higher vibrotactile thresholdsin the high exposure group compared to low and medium groups. Similar effectswere observed with the three measures of exposure, although the associationswere strongest with urinary and weakest with nail measures. No significantdifferences were found in any visual measures. Arsenic is presently regulated as acarcinogen. Results of the current study indicate neurosensory effects of arsenicexposure at concentrations well below the 1000 ug/L level specified by NRC(1999) and suggest that non-carcinogenic end-points such as tactile thresholds areuseful in the risk assessment of exposure to arsenic in drinking water.

CORRESPONDING AUTHOR: David Otto, EPA/Human Studies Division(MD-58B), Research Triangle Park, NC 27711, USA.

DISCLAIMER: This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.


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44

ARSENIC INDUCED CARCINOGENESIS: PERTURBATIONS INGLOBAL AND HA RAS METHYLATION PATTERNS IN METHYL-DEFICIENT C57BL/6 MICE; RESULTS OF A CHRONIC ANIMAL

BIOASSAY

John R. Froines Ph.D, University of California, Los Angeles

Abstract: We have studied the effect of arsenic and methyl-deficiency on themethylation patterns of genomic and Ha-ras specific DNA. We hypothesize thatincreased susceptibility to arsenic induced carcinogenesis results from a depletion ofmethyl group reserves and a subsequent reduction in intracellular DNA methylationreactions. Cellular methyl groups are depleted by chronic administration andmetabolism of inorganic arsenic. Nutritional depletion of methyl groups furthercontributes to the deficiency resulting in a compromised DNA methylation process.We demonstrate that coadministration of sodium arsenite and a methyl-deficient dietto C57BL/6 mice results in global DNA and Ha-ras specific hypomethylation.Methylation changes in DNA are associated with abnormal gene expression, cellgrowth and possibly cancer. A 90-day subchronic animal bioassay conducted by ourlaboratory indicates that animals administered arsenic and a methyl-deficient dietdisplay a dose-dependent increase in hypertrophy and hyperplasia of the bladderepithelium as well as fatty changes and microgranulomas in livers. The associationbetween the observed hypomethylation and the histological changes has not beendetermined. A chronic animal bioassay was conducted to examine the long-termeffects of arsenic and methyl-deficiency on C57BL/6 mice. Methyl-deficient micewere administered sodium arsenite at 1.0 and 2.0 mg/kg/day. Exposure occurred for18 months after which animals were necropsied and tissues analyzed forhistopathological changes. Preliminary results will be discussed.

CORRESPONDING AUTHOR: John R. Froines, Ph.D., Department ofEnvironmental Health Sciences, University of California, Los Angeles, Box951772, Los Angeles, CA 90095-1772


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45

LOW DOSE ARSENATE IN DRINKING WATER PREVENTS SKINTUMOR FORMATION IN A DMBA/TPA DEPENDENT MOUSE MODEL

Catherine B. Klein, Ph.D., NYU School of Medicine, Liza Snow, Ph.D., NewYork University School of Medicine and Deakin University, Australia; MaartenC. Bosland, D.V.M., Ph.D. NYU School of Medicine

Although arsenic is an established human carcinogen, animal models ofarsenic carcinogenesis have had limited success. We have used the classicDMBA/TPA mouse skin tumour model to assess the ability of arsenic to act as aco-promoter or progressor of tumour formation in (C57Bl/6 X CBA) F1 mice.The mice were given arsenic, as sodium arsenate, in their drinking water at one oftwo sub-toxic doses, 0.2 mg/L or 2.0 mg/L starting two days prior to tumourinitiation with dimethylbenzanthracene (DMBA), followed by a standardpromotion regime using the phorbol ester, TPA, with continued exposure toarsenic in the water. Several groups of mice were given an antioxidant, N-acetylcysteine (NAC), rather than As(V) in their water and other groups were givenboth As(V) and NAC. Our results have shown, much to our surprise, that arsenicproduced a significant dose-dependent (41 to 63%) reduction in the papillomaformation caused by the DMBA/TPA treatment. NAC alone also reduced tumourformation by over 30% and the low dose of As(V) plus NAC together gave anadditive response that equalled the 60% reduction in tumour formation producedby 2.0 mg/L As(V) alone. This result is consistent with our in vitro data that showthat chronic exposure to As(III) causes decreased AP-1 and NF-kB binding and adecrease in the cellular response to TPA. Evaluation of the tumour pathology andAs levels in tissues is ongoing and results will be presented along with assays ofcellular response after long-term As exposure.

CORRESPONDING AUTHOR: Elizabeth T. Snow, Ph.D., Centre for Cellularand Molecular Biology, School of Biological and Chemical Sciences, DeakinUniversity, 221 Burwood Highway, Burwood VIC 3125 AUSTRALIA


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46

MOLECULAR MECHANISM OF TRANSFORMATION IN MOUSE FIBROBLASTS INDUCED BY LOW DOSE OF ARSENIC

Yu Hu 1,2 MPH, Ph.D, Ximei Jin 1,2 M.D, Guoquan Wang M.D2,Elizabeth T Snow1 Ph.D. 1.School of Biological and ChemicalSciences, Deakin University, Australia. 2. School of Public Health,Xinjiang Medical University, China

Arsenic is an important environmental chemical because it isnot only a critical compound for some medicine, especially inleukemia treatment but also associated with the occurrence of adversehealth effects in human exposed by drinking water as well asoccupational exposure. However, mechanism of action of Arsenic isstill unclear. Alteration in intracellular redox status has been proposedas one of major actions by arsenic. The purpose of this investigationis to study the effect of As (III) on regulation of redox gene such asRef-1, GR, TRX and TR as well as prot-oncogene and tumor suppressgene expression both in short-term and long-term treatment in mousefibroblast 3T3 cell. The interaction between As (III) and TPA andH2O2 on these genes expression was also investigated. The resultsshowed that As (III) up-regulates the expression of TRX, TR, GR andRef-1, especially after long-term exposed to sub-micromolar dose As(III), which is paralleled with cells morphology changes andmalignant transformation after long-term treatment with no toxic doseAs (III). Our results suggested that up-regulation of TRX and TR anddown-regulation of c-jun, c-fos as well as p53 after long-term As (III)exposure may be required for induction of regeneration hyperplasiawhich is close related to tumorigenesis through redox-regulate proteinkinases and modulate enzyme activities, cell surface or intercellularreceptors and transcription factors.

CORRESPONDING AUTHOR: Yu Hu MPH, Ph.D School of Public Health,Xinjiang Medical University, 8 XinYi Rd,Urumqi, Xinjiang, 830054 China


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47

HEALTH EFFECT MONITORING TO DNA DAMAGE OFARSENIC EXPOSURE

Hiroshi Yamauchi, Ph.D., Masahito Aminaka, Katusmi Yoshida, M.D., Ph.D., Dept.of Preventive Medicine, St. Marianna University School of Medicine, Kawasaki,JAPANGuifan Sun, M.D., Ph.D., School of Public Health, China Medical University,Shenyang, CHINA

The DNA damage is generated by the exposure of oxidized stress. This researchintroduces the biological health effect monitoring method, which evaluates the DNAdamage caused to the arsenic exposure by 8-hydroxydeoxyguanosine (8-OHdG)concentration in urine.

The research subjects are five group: 1) 248 Japanese healthy people, 2) 95Chinese healthy people, 3) 52 patients of acute arsenic poisoning, 4) 165 patients ofchronic arsenic poisoning in China, 5) 31 Japanese fishermen.

The average concentrations of arsenic in urine of Japanese healthy people, acutearsenic poisoning patients, chronic arsenic poisoning patients and Japanese fishermenis 45.6136.6, 11481703 (after 10 days), 2581326 and 173174.0 mg As/gcreatinine, respectively. The average concentrations of 8-OHdG in urine of Japanesehealthy people, Chinese healthy people, acute arsenic poisoning patients, chronicarsenic poisoning patients and Japanese fishermen is 15.415.6, 14.519.0, 25.219.8,17.719.6 and 21.316.4 ng/mg creatinine, respectively.

As for the excretion of 8-OHdG in urine from acute arsenic poisoning patients,the tendency to actualize after the day tenth when arsenic had been taken wasobserved. On the other hand, 8-OHdG concentrations in urine were recovered by thespontaneous recovery within the range of a normal value one year from about halfa year later.

8-OHdG concentrations in urine of the patient with chronic arsenic poisoning riseby the inorganic arsenic exposure. When one year has passed since the arsenicexposure was stopped, 8-OHdG concentrations in urine has been recovered within therange of a normal value.

For a general healthy person, in people who took the arsenic of excessive frommeal, the upturned of 8-OHdG concentrations in urine was observed.

It is thought that the measurement of 8-OHdG concentrations in urine is aneffective, biological health effect monitoring method of the arsenic exposure.

CORRESPONDING AUTHOR: Hiroshi Yamauchi, Ph.D., Department ofPreventive Medicine, St. Marianna University School of Medicine, Kawasaki 216-8511, JAPAN.


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49

LABORATORY AND FIELD EVALUATION OF POTENTIAL ARSENICEXPOSURE FROM MINE TAILINGS TO GRAZING CATTLE

Scott Bruce, BSc(Hons)., Barry Noller, PhD., Jack C. Ng, PhD., National ResearchCentre for Environmental Toxicology, The University of Queensland, Australia

In Australia, a main future use of rehabilitated mine-land is to stock grazinganimals. Criteria for environmental management and rehabilitation of mine sites havebecome more stringent with the increasing awareness of the potential of harmfulelements including arsenic in tailings. Bioavailability data are lacking to providerealistic health risk assessment of arsenic from mine tailings in Australian conditions.

For the evaluation of comparative bioavailability, groups of 3 cattle were fed5 days a week a diet spiked with mine tailings or sodium arsenate or arsenite for 8months. Blood, biopsy of the muscle and liver were periodically collected to monitorarsenic accumulation. At necropsy, blood, muscle, liver, kidney and other saleabletissues were measured for arsenic concentrations.

For the field validation, cattle were allowed to graze on rehabilitated tailingsfacilities over 8-9 months. Our results indicated that although the concentrations ofarsenic in the tissues were higher than those of the control site, the levels were belowthe Australian maximum permissible concentrations for beef intended for humanconsumption. The rehabilitated mine tailings under the test conditions appear to besuitable for grazing animals with no foreseen adverse health effects.

Results obtained from this animal model should be a useful tool forrehabilitation design of mined land in order to minimise health effects for animals andhumans. More data of this type will help regulatory agencies to develop guidelinevalues and policy in relationship to mine closure.

CORRESPONDING AUTHOR: Jack C. Ng, PhD., National Research Centre forEnvironmental Toxicology, The University of Queensland, 39 Kessels Road, CoopersPlains, Brisbane, Australia 4108. Email: [email protected]


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50

EVIDENCE FROM MOUSE CARCINOGENESIS STUDIES SUGGESTSTHAT ARSENIC REQUIRES A CARCINOGENIC PARTNER

Toby G. Rossman, Ph.D., Ahmed N. Uddin, MD, Ph.D., Fredric J. Burns, Ph.D. andMaarten C. Bosland, DVM, Ph.D. , New York University School of Medicine

Epidemiological studies show an association between inorganic arsenic in drinkingwater and increased risk of cancers, yet animal models for arsenic carcinogenesis havenot been successful. This lack hinders mechanistic studies of arsenic carcinogenesis.Previously, we found that low concentrations of arsenite are not mutagenic, but canenhance the mutagenicity of other agents. This comutagenic effect appears to resultfrom inhibition of DNA repair by arsenite, but not via inhibition of DNA repairenzymes. Rather, arsenite disrupts p53 function and enhances proliferative signaling(Vogt and Rossman, Mutation Res. 478:159,2001). Failure to find animal models forarsenic carcinogenesis might indicate that arsenite is not a complete carcinogen, butrather acts as an enhancing agent (not a promoter, but a cocarcinogen). To test thishypothesis, Skh1 mice were given 10 mg/l sodium arsenite in drinking water (or not)and irradiated with 1.7 KJ/m2 solar UVR 3 times weekly. After 26 weeks, no tumorsappeared in any organs in control mice or in mice given arsenite alone, but irradiatedmice given arsenite had a 2.4-fold higher skin tumor yield than mice given UVRalone. The tumors were mostly squamous cell carcinomas, and were larger and moreinvasive in mice given UVR plus arsenite. These results support the hypothesis thatarsenic acts as a cocarcinogen with a second (genotoxic) agent by inhibiting DNArepair and/or enhancing positive growth signaling. Similar experiments are beingcarried out in a lung cancer model. The shape of the dose/response curve for skincarcinogenesis is also being determined.

CORRESPONDING AUTHOR: Toby G. Rossman, Ph.D., Nelson Institute ofEnvironmental Medicine, New York University School of Medicine, 57 Old ForgeRoad, Tuxedo, NY 10987, USA [email protected]


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51

MECHANISMS INVOLVED IN SODIUM ARSENITE-INDUCEDCYTOGENETIC ALTERATIONS

Te-Chang Lee, Ph.D., Institute of Biomedical Sciences, Academia Sinica and Instituteof Pharmacology, National Yang-Ming University; Ling-Huei Yih, Ph.D., GraduateInstitute of Pharmacology and Toxicology, Tzu Chi University

Multistep carcinogenesis requires a number of genetic changes. Inorganicarsenic has been well documented to induce cytogenetic alterations such asendoreduplication (diplochromosomes), chromosome aberrations, sister chromatidexchanges, and aneuploidy in both in vivo and in vitro systems. We have demonstratedthat treatment of human fibroblasts (HFW) with 5 µM arsenite for 24 h resulted in18% of subclones with one chromosome loss. The aneugenic activity of arsenite wasconfirmed by formation of kinetochore positive micronuclei. Our recent datademonstrated that arsenite could mimic spindle poisons to induce mitotic arrest inseveral human cell lines. The interference of mitotic spindles by arsenite would leadto the appearance of c-anaphase. Since arsenite-induced mitotic arrest and c-anaphasewere abrogated by staurosporine, a kinase inhibitor, an unidentified cascade forprotein phosphorylation and dephosphorylation was possibly involved in arsenite-induced mitotic disturbance and cytogenetic alterations. Cytogenetic alterations andchromosomal instability are frequently reported to be due to the failure of spindle-assembly checkpoints.

Evidence to date shows that most cancers manifest the genetic instability. Inmost cancers, the instability is observed at the chromosome level, resulting in lossesand gains of whole chromosomes or large portions thereof. In our studies, we havedemonstrated that arsenic may cause DNA strand breaks, induce p53 accumulation,and exert its aneugenic and/or clastogenic effects through disturbance of mitoticevents and attenuation of spindle dynamics.

CORRESPONDING AUTHOR: Te-Chang Lee. Ph. D., Institute of Biomedicalsciences, Academia Sinica, Taipei 115, Taiwan and Institute of Pharmacology,National Yang-Ming University, Taipei 112, Taiwan.


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52

CARCINOGENICITY OF DIMETHYLARSINIC ACID AND RELEVANTMECHANISMS

Shoji Fukushima, M.D., Hideki Wanibuchi, M.D., Min Wei, M.D., andKeiichirou, Morimura, M.D. Department of Pathology, Osaka City UniversityMedical School, Japan

Precise mechanisms by which arsenic induces cancer are unknown, in large partdue to the lack of an appropriate animal mode. In the present set of experiments,we focused on a major organic metabolite of arsenic, dimethylarsinic acid(DMA), found in most mammals including humans. We examined carcinogenicityof DMA in male F344 rats in a 2-year carcinogenicity test, in addition to assessinggenetic alteration patterns in the induced tumors. Furthermore, to test thehypothesis that ROS may play a role in DMA carcinogenesis, 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation in urinary bladder was examined. From weeks 97-104, urinary bladder tumors were observed in rats treated withDMA at doses of 50 ppm (incidence, 29%) and 200 ppm (incidence, 36%), butnot at doses of 0 and 12.5 ppm. Mutation analysis showed these tumors to have alow rate of H-ras mutations. No alterations of the p53, K-ras or _-catenin geneswere found, whereas aberrant protein expression of p27kip1, cyclin D1 and COX-2could be demonstrated in the urinary bladder lesions by immunohistochemistry. 8-OHdG formation level in urinary bladder DNA was significantly increased aftertreatment with 200 ppm DMA in the drinking water for 2 weeks, as comparedwith the controls. In conclusion, the present work provides unequivocal evidence that DMA is acomplete carcinogen for the rat urinary bladder. DMA-induced urinary bladdertumors may occur as the result of accumulations of diverse genetic alterations.Furthermore, generation of ROS is likely to play an important role in DMAcarcinogenesis.


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53

TRANSPLACENTAL CARCINOGENICITY OF INORGANIC ARSENICIN MICE: INDUCTION OF HEPATIC, OVARIAN, PULMONARY AND

ADRENAL TUMORS

Michael P. Waalkes, Ph.D., Jie Liu, Ph.D., NCI at NIEHS; Jerrold M. Ward,D.V.M., Ph.D., NCI at Frederick; Bhalchandra A. Diwan, Ph.D., SAIC-Frederick

Since gestation is a period of high sensitivity to chemical carcinogenesis,we performed a transplacental carcinogenicity study where groups (n = 10) ofpregnant C3H mice received drinking water containing sodium arsenite at 0, 42.5and 85 ppm arsenite ad libitum from day 8 to18 of gestation. Dams were allowedto give birth, offspring were weaned (4 weeks) and put into gender-based groups(n = 25) according to maternal exposure. During the study, which lasted up to 90weeks, survival and body weights of the offspring were not reduced by the arsenicexposure compared to control. A complete necropsy was performed on all miceand tissues were examined by light microscopy in a blind fashion. In maleoffspring, there was a marked, dose-related increase in hepatocellular carcinomaincidence (control, 12%; 42.5 ppm, 38%; 85 ppm, 61%) and in liver tumormultiplicity (tumors/liver; 5.6-fold over control at 85 ppm). A dose-relatedincrease in adrenal tumor incidence and multiplicity also occurred. In femaleoffspring, dose-related increases occurred in ovarian tumors (control, 8%; 42.5ppm, 26%; 85 ppm, 38%), and in uterine proliferative lesions (hyperplasia plustumors; control, 16%; 42.5 ppm, 56%; 85 ppm, 63%). Arsenic also induced lungcarcinoma and oviduct proliferative lesions in females. In non-neoplastic areas ofliver from arsenic exposed animals there was a marked over-expression ofestrogen receptor-" and cyclin D1, a suspected hepatic oncogene. These resultsdemonstrate that inorganic arsenic exposure, as a single agent, can be carcinogenicin mice. (Supported in part by NO1-CO-56000).

CORRESPONDING AUTHOR: Michael P. Waalkes, Ph.D., InorganicCarcinogenesis Section, Laboratory of Comparative Carcinogenesis, NCI atNIEHS, 111 Alexander Drive, MD F0-09, PO Box 12233, Research TrianglePark, NC 27709, USA.


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55

CHARACTERIZATION OF THE ENZYMES INVOLVED IN THEBIOTRANSFORMATION OF INORGANIC ARSENIC BY HUMANS

H. Vasken Aposhian, Ph.D., Robert A Zakharyan, M.D., Ph.D., AdrianaSampayo-Reyes, Ph.D., Timothy R. Radabaugh, B.S., and Dean E. Carter,University of Arizona

The biotransformation of inorganic arsenate to DMA involves a series ofenzymatic steps. We have previously reported that the enzyme responsible for thereduction of arsenate to arsenite is human liver arsenate reductase. Our recent studiesbased on amino acid homology and other properties demonstrate that human liverarsenate reductase and human purine nucleoside phosphorylase (PNP) are identicalproteins. The reaction requires inosine and dihydrolipoic acid which is the mostpotent naturally occurring dithiol. GSH is relatively inactive. PNP is an essentialenzyme involved in purine and thus nucleic acid metabolism. Arsenatereductase/PNP will not reduce MMA(V).The reduction of MMA(V) to the very toxic and reactive MMA(III) is catalyzedby human liver MMA(V) reductase which our lab has demonstrated to be identical to the new omega member of the glutathione S-transferase superfamily.MMA(V) reductase has an absolute requirement for GSH. Most of the othermembers of the glutathione-S-transferase superfamily will not reduce MMA(V). Although at the time of this writing, the sequence of the human arsenicmethyltransferase is not known, in vitro and in vivo studies will be correlated tocompile a scaffold for the interactions of inorganic arsenic and its methylatedmetabolites, including MMA(III) and DMA(III), with body constituents to attemptan explanation for the toxicity of ingested inorganic arsenic.

CORRESPONDING AUTHOR: H. Vasken Aposhian, Ph.D., Department ofMolecular and Cellular Biology, University of Arizona, Life Sciences SouthBuilding, P.O. Box 210106, Tucson, AZ, 85721-0106, USA.


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56

PATHWAYS OF ARSENIC TRANSPORT AND DETOXIFICATION INPROKARYOTES AND EUKARYOTES

Barry P. Rosen, Department of Biochemistry and Molecular Biology, Wayne StateUniversity, School of Medicine.

Life may have first arisen in deep oceanic hydrothermal vents that were rich in toxicmetals including arsenic. Maintaining suitable intracellular concentrations of essentialmetals while excluding toxic metals such as arsenic was one of the earliest challenges ofthe first cells. This ancient environmental challenge has been the driving force for theevolution of mechanisms for metal ion homeostasis and detoxification. Even today toxicmetals such as arsenic enter the ecosphere from geochemical sources(http://co.water.usgs.gov/trace/arsenic/). It is little wonder that in every organismexamined there are transport systems that detoxify metal ions by catalyzing extrusionfrom the cytosol (1,2). This presentation will focus on the mechanisms of arsenic transport and detoxificationin the Escherichia coli and Saccharomyces cerevisiae (3). In both As(V) is taken up byphosphate transporters, and aquaglyceroporins GlpF (4) and Fps1p facilitate As(III) entryinto cells. The first step in arsenate detoxification is biotransformation to As(III) by anarsenite reductase, ArsC (5) or Acr2p (6). In both organisms, the next step involvesextrusion of As(III) from the cytosol. In E. coli extrusion is catalyzed by the ArsABATPase (7). In yeast this is carried out by the arsenite carrier, Acr3p (8). In addition,Ycf1p, a homologues of the human MRP drug pump, transports glutathione conjugatesof As(III) into the yeast vacuole (8). Identification of the routes of arsenic uptake and efflux in humans is of importance forunderstanding its action as a human carcinogen and as a chemotherapeutic drug in thetreatment of leukemia. While at least one extrusion system has been identified, wherearsenic is pumped into bile by MRP2 in the form of As(GS)3, the pathways for arseniteuptake are unknown. Recently we have shown that the mammalian aquaglyceroporinAQP9 facilitates arsenite uptake into cells, suggesting that this protein could be apathway for arsenite uptake in humans. Supported by NIH grants GM52216 andES10344. REFERENCES: 1. Rensing, C., Ghosh, M., and Rosen, B. P. (1999) J Bacteriol 181, 5891-5897 2. Gatti, D., Mitra, B., and Rosen, B. P. (2000) J Biol Chem 275, 34009-34012 3. Rosen, B. P. (1999) Trends Microbiol 7, 207-212 4. Sanders, O. I., Rensing, C., Kuroda, M., Mitra, B., and Rosen, B. P. (1997) J Bacteriol179, 3365-3367 5. Shi, J., Vlamis-Gardikas, A., Åslund, F., Holmgren, A., and Rosen, B. P. (1999) J BiolChem 274, 36039-36042 6. Mukhopadhyay, R., Shi, J., and Rosen, B. P. (2000) J Biol Chem 275, 21149-21157 7. Rosen, B. P., Bhattacharjee, H., Zhou, T., and Walmsley, A. R. (1999) BiochimBiophys Acta 1461, 207-215 8. Ghosh, M., Shen, J., and Rosen, B. P. (1999) Proc. Natl. Acad. Sci. USA 96, 5001-5006 CORRESPONDING AUTHOR: Barry P. Rosen, Ph.D., Department of Biochemistry& Molecular Biology, Wayne State University, School of Medicine, Detroit, MI 48201,USA.


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57

THE PATHWAY OF ARSENIC METHYLATION

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

Understanding the metabolic processes that convert inorganic arsenic intoits methylated metabolites is central to understanding the mechanistic bases of thetoxicity and carcinogenicity of this metalloid. We purified a novel S-adenosyl-L-methionine: arsenic(III) methyltransferase from liver cytosol of adult male Fischer344 rats that catalyzes transfer of a methyl group from S-adenosyl-L-methionineto trivalent arsenicals producing methylated and dimethylated arsenicals. ThemRNA for this protein predicts a 369 amino acid-residue protein (molecular mass41056 D) that contains common methyltransferase sequence motifs. Based onsimilarities in the sequence of the rat protein and other predicted proteinsequences, this enzyme is designated as rat Cyt19. Rat Cyt19 mRNA is expressedin many rat tissues and human Cyt19 mRNA is expressed in HepG2 cells, ahuman hepatoma cell line that methylates arsenic. However, Cyt19 mRNA is notfound in UROTsa cells, a human urothelial cell line that does not methylatearsenic. Recombinant rat Cyt19 is fully active as an arsenic methyltransferase. Human Cyt19 is a 375 amino acid-residue protein that is quite similar in sequenceto rat Cyt19 and recombinant human Cyt19 is also an arsenic methyltransferase. The catalytic functions of both rat and human Cyt19 have an absolute requirementfor a dithiol-containing molecule. (This abstract does not necessarily reflect EPApolicy).


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58

ARSENIC-INDUCED CHANGES IN CELL ADHESION MOLECULES(CAMS), E-SELECTIN AND MONOCYTE-CHEMOATTRACTANTPROTEIN-1 (MCP-1) EXPRESSION IN HUMAN UMBILICAL VEIN

ENDOTHELIAL CELLS (HUVEC)

Michael W. Lieberman, Subbarao V. Kala, Geeta Kala, C. Wayne Smith, andHaiyun Y. Cheng. Departments of Pathology and Pediatrics, Baylor College of Medicine, Houston,TX 77019

Arsenic is a risk factor in cardiovascular disease, yet relatively little is knownabout the molecular mechanisms responsible for arsenic-induced cardiovasculardisease. Because CAMs, and Selectins are believed to be involved inatherogenesis, we are evaluating the effects of arsenic (sodium arsenite) and itsmethylated products, monomethylarsonic acid (MMAV), dimethylarsenic acid(DMAV) and monomethylarsonous acid (MMAIII) on the expression of ICAM-1,VCAM, E-selectin and MCP-1 in HUVEC. Sodium arsenite, MMAV and DMAV

do not alter the basal expression of these molecules when added to passage 2HUVEC as determined by ELISA. TNFα or LPS stimulate the expression ofthese molecules 3 to 8 fold within 6 hrs. Sodium arsenite inhibits the TNFα- orLPS- stimulated expression of ICAM, VCAM, E-Selectin and MCP-1 in thesecells at relatively low concentrations (5-10 µM), while MMAV and DMAV arewithout effect. Since NFκB activation is known to be important in TNFα- or LPS-induced expression of CAMs and Selectins, we have examined the effects ofsodium arsenite on NFκB activity (determined by EMSA) as well as thephosphorylation of IκB (Western blot). Sodium arsenite inhibits TNFα- or LPS-stimulated IκB phosphorylation and NFκB activation in these cells. It ispostulated that arsenite inhibits TNFα- or LPS- stimulated synthesis of ICAM,VCAM and E-selectin by preventing phosphorylation of IκB and NFκBactivation.

(Supported by NIH grant ENVIRONMENTAL SCIENCES-10289)


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59

ENZYMATIC REDUCTION OF ARSENATE IN HEPATICMITOCHONDRIA AND CYTOSOL

Zoltán Gregus, M.D., Ph.D., D.Sc. and Balázs Németi, M.D., University of Pécs,Medical School

Arsenate (AsV), a typical form of environmental arsenic, is converted inthe body into more toxic trivalent forms, primarily arsenite (AsIII). We havestudied reduction of AsV to AsIII in isolated rat liver mitochondria and cytosol.

AsV-exposed mitochondria, which take up AsV like phosphate, rapidlyformed and exported AsIII. Mitochondrial AsIII formation depended on thefunctional integrity of mitochondria and was sensitive to inhibitors of oxidativephosphorylation. Solubilization of mitochondria abolished their AsV reductaseactivity even in the presence of glutathione and NAD(P)H, precluding isolation ofmitochondrial AsV reductase.

Rat liver cytosol also reduced AsV, provided an appropriate thiol, e.g.,dithiothreitol (DTT), dimercaptopropanol or dimercaptopropanesulfonate, waspresent. Based on the following findings, we have identified this thiol-dependentcytosolic AsV reductase as purine nucleoside phosphorylase (PNP), an enzymethat normally uses phosphate to cleave purine nucleosides (inosine or guanosine)into bases (hypoxanhine or guanine) and ribose-1-phosphate, but can also use AsVinstead of phosphate. Cytosolic DTT-supported AsV reduction was increased upto 100-fold by inosine or guanosine, but was inhibited by phosphate,hypoxanhine, guanine and PNP inhibitors. AsV reductase and PNP activitiesperfectly coeluted during chromatography of cytosol. Purified PNP exhibited AsVreductase activity provided both DTT and inosine were present. The AsVreductase activity of PNP exhibited a chemical responsiveness similar to that ofthe cytosolic AsV reductase.

Although mitochondria and cytosolic PNP can reduce AsV, their in vivorole in formation of AsIII from AsV remains to be clarified. (For moreinformation see Toxicol. Sci. 66(1-S): 83-84, 2002.)

CORRESPONDING AUTHOR: Zoltán Gregus, M.D., Ph.D., D.Sc., Dept. ofPharmacology, Univ. of Pécs, Med. School, Szigeti út 12, H-7643 Pécs, Hungary.


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60

ROLE OF MITOCHONDRIA IN THE GENOTOXICITY OF ARSENIC INMAMMALIAN CELLS

Su-Xian Liu1, Mercy M. Davidson2, Mohammad Athar3 and Tom K. Hei1,4,1Center for Radiological Research, 2Department of Neurology, 3Department ofDermatology, College of Physicians & Surgeons and, 4Department ofEnvironmental Health Sciences, Joseph Mailman School of Public Health,Colombia University, New York, NY., 10032

Although arsenic is a well established human carcinogen, its carcinogenicmechanism is not clear. Using the human hamster hybrid (AL) cell assay that isproficient in the recovery of deletion mutants, we showed previously that arsenicis a potent gene and chromosomal mutagen and that reactive oxygen speciesmediate its genotoxic response (PNAS 95:8103, 1998; PNAS 98: 1643, 2001). Toascertain if mitochondria contributed to the genotoxicity of the trivalent sodiumarsenite, we used two complementary approaches. Treatment of enucleated cellswith arsenic followed by rescue fusion with karyoplasts resulted in a mutant yieldthat was 3 fold higher than untreated cells. In contrast, arsenic treatment ofmitochondrial function/DNA depleted cells, generated by pretreatment with Rhodamine-6G, followed by rescue fusion with cytoplasts resulted in fewmutations. These data illustrate that nucleus is not the only target of thecarcinogenic metal and that mitochondria may also play an important role in thegenotoxic response of mammalian cells to the metalloid metal as well.

CORRESPONDING AUTHOR: Tom K. Hei, Ph.D., Center for RadiologicalResearch, Columbia University, Vanderbilt Clinic 11-205, 630 West 168th Street,New York, NY., 10032


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62

METHYLATED ARSENICALS AND GENE TRANSCRIPTIONREGULATION

Miroslav Styblo, Ph.D., Zuzana Drobná, Ph.D., Ilona Jaspers, Ph.D., University ofNorth Carolina at Chapel Hill

Methylated arsenicals that contain either trivalent or pentavalent arsenic are productsof the enzymatic methylation of inorganic arsenic (iAs) in humans. Unlike theirpentavalent counterparts, methylated trivalent arsenicals, methylarsonous acid(MAsIII) and dimethylarsinous acid (DMAsIII), are more cytotoxic, genotoxic andmore potent enzyme inhibitors than iAs. Previous studies on molecular mechanismsof carcinogenic effects of iAs indicated that this arsenical does not act through classicgenotoxic or mutagenic mechanisms, but rather is a tumor promoter that interfereswith signal transduction pathways. Trivalent iAs, arsenite (iAsIII), has been shown tomodify expression and/or DNA binding activities of several transcription factors,thereby modulating cell growth and proliferation. However, effects of methylatedarsenicals on gene transcription regulation have not been thoroughly characterized.We have examined the composition and DNA binding activity of one of the majortranscription factors, activating protein-1 (AP-1), in several types of human cellsexposed to iAsIII, or to methylated trivalent arsenicals. All trivalent arsenicals, iAsIII,MAsIII and DMAsIII, induced phosphorylation of c-Jun, DNA binding activity of AP-1, and/or AP-1-dependent gene transcription in human primary hepatocytes, HepG2,and urinary bladder cell lines, UROtsa and T24. Regardless of cell type, MAsIII andDMAsIII were considerably more potent inducers of c-Jun phosphorylation and AP-1activation than was iAsIII. Among cell types examined, UROtsa cells, a normalhuman urothelium cells line, were the most sensitive to trivalent arsenicals, especiallyto MAsIII. These results indicate that methylated trivalent arsenicals are more potentthan iAsIII in inducting AP-1-dependent gene transcription in human tissues,particularly in bladder urothelium. (Supported by NIH grant ES09941.)

CORRESPONDING AUTHOR: Miroslav Styblo, Ph.D., Department of Pediatricsand the Center for Environmental Medicine and Lung Biology, University of NorthCarolina at Chapel Hill, CB# 7220, Chapel Hill, NC 27599-7220, USA.


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63

ALTERED GENE EXPRESSION IN KERATINOCYTES FOLLOWINGARSENIC EXPOSURE

Dori R. Germolec, Ph.D., Kevin J. Trouba, Ph.D., Hisham K. Hamadeh, Ph.D.,Rupesh P. Amin, Ph.D., Kristen Geisenhoffer and Cynthia A. Afshari, Ph.D.,National Institute of Environmental Health Sciences

Previous studies in our laboratory suggest that arsenic modulates neoplasticdisease in the skin by inducing overexpression of genes encoding specificcytokines and growth factors. Using cDNA microarrays, we have determined thatnon-toxic concentrations of arsenic modulate gene expression (e.g., oxidativestress, glutathione metabolism, heat shock/stress response, cell proliferation, andDNA damage) in normal human epidermal keratinocytes (NHEK). Based onmicroarray data, cyclooxygenase-2 (Cox-2), a pro-inflammatory protein that isregulated by oxidative stress, is robustly induced by arsenic in a dose- and time-dependent manner. Northern blotting confirms increases in gene expression. Arsenic influences Cox-2 expression posttranscriptionally at the protein level,suggesting a functional relationship between arsenic exposure and prostaglandinsynthesis. The mechanism(s) by which arsenic regulates Cox-2 expressionappears to be mediated in part by mitogen and stress-related signal transducers. PD98095 and SB202190, two specific inhibitors of mitogen and stress-relatedsignal transduction, respectively, serve to partially attenuate the ability of arsenicto upregulate Cox-2 expression. Arsenic-induced Cox-2 expression in NHEK isassociated with cellular stress, demonstrated by the robust induction of Serinethreonine kinase 25 and NADPH oxidoreductase: two markers of oxidative stress. Additional studies in our laboratory using the Tg.AC mouse in vivo indicate thatboth inorganic and methylated arsenicals can modulate cell proliferation andcytokine expression, an effect that may be directly or indirectly associated withCox-2 expression. Future studies will examine the relationship between arsenic-induced pro-inflammatory cytokines, Cox-2, and stress-related gene expressionand the molecular mechanisms through which arsenic regulates Cox-2 expression.

Corresponding Author: Dori R. Germolec, Ph.D., Environmental ImmunologyLaboratory, National Institute of Environmental Health Sciences, PO Box 12233,RTP, NC, 27709


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64

MULTIDRUG RESISTANCE TRANSPORT PROTEINS IN ARSENICTOXICOLOGY

Jie Liu, Ph.D., Michael P. Waalkes, Ph.D., NCI at NIEHS; Yaping Liu, M.D. and Curtis D. Klaassen, Ph.D., University of Kansas MedicalCenter

We have shown that cultured rodent cells chronically exposed to inorganicarsenic (As) develop tolerance to the metalloid associated with increased As efflux.These As-tolerant cells show increased expression of several transporters includingmultidrug resistance protein Mrp1 and Mrp2, as well as the multidrug resistance geneMDR1. Mrp inhibitor MK571 and P-glycoprotein inhibitor PSC833 increased Ascytotoxicity in these cells by increasing cellular As accumulation. However, whethersuch phenomena are relevant in vivo is not known. Thus, the mdr1a/1b(-/-) mice,which lack mdr1-type P-glycoproteins, were examined for sensitivity to As toxicityand accumulation. The mdr1a/1b(-/-) and wild-type mice were given a single dose ofsodium arsenite (12-19 mg/kg, sc), and toxicity was examined 24 hr later. Themdr1a/1b(-/-) mice were more sensitive than wild-type mice to As-induced lethality.Histologically, As produced more frequent and more severe lesions in the liver andkidney of mdr1a/1b(-/-) mice than in wild-type mice. Serum alanine aminotransferaseactivity and blood urea nitrogen levels, indicative of hepatic and renal damagerespectively, were increased 4-6 fold in the mdr1a/1b(-/-) mice as compared to 1-2fold increases in wild-type mice. The mdr1a/1b(-/-) mice accumulated more As inthe liver (15.3 vs 5.2 µg/g), kidney (7.23 vs 3.22 µg/g), small intestine (3.98 vs 1.57µg/g), and brain (0.45 vs 0.17 µg/g), as compared to wild-type mice 24 hr aftersodium arsenite (14 mg/kg, sc) administration. These data indicate multidrug-resistance proteins and P-glycoproteins could function together to reduce cellular Asaccumulation and thus make animals resistant to acute As toxicity.

Corresponding Author: Jie Liu, Ph.D., Inorganic Carcinogenesis Section, Laboratoryof Comparative Carcinogenesis, NCI at NIEHS, 111 Alexander Drive, ResearchTriangle Park, NC 27709, USA


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65

GENE REGULATION BY LOW DOSE ARSENIC IN CULTUREDHUMAN CELLS

Liza Snow, Ph.D., Michael Schuliga, Ph.D., Yu Hu, M.D., Deakin University,Australia

We have evaluated the molecular responses of human epithelial cells tolow dose arsenic to ascertain how target cells may respond to physiologicallyrelevant concentrations of arsenic. Data gathered in numerous experiments indifferent cell types all point to the same conclusion: low dose arsenic induces aprotective response against subsequent exposure to oxidative stress or DNAdamage, whereas higher doses often provoke synergistic toxicity. In particular,exposure to low, sub-toxic doses of As(III) causes coordinate up-regulation ofmultiple redox and redox-related genes including thioredoxin, thioredoxinreductase, glutathione reductase, and γ-glutamylcysteine synthetase (required forGSH synthesis). Glutathione peroxidase is down-regulated in fibroblasts, but up-regulated in keratinocytes. The maximum effect on these redox genes occurs after24 hours exposure to 5 to 10 :M As(III). This is 10-fold higher than themaximum As concentrations required for induction of DNA repair genes (Sykoraand Snow), but within the dose region where DNA repair genes are coordinatelydown regulated. Although arsenic toxicity may be caused, in part, by the transientformation of reactive oxygen species (ROS), the observed effects on redox geneexpression are, to a large extent, independent of ROS formation. These changes ingene regulation are brought about in part by changes in DNA binding activity ofthe transcription factors AP-1 and NF-κB. Although sub-acute exposure tomicromolar As(III) up-regulates transcription factor binding, chronic exposure tonanomolar As causes persistent down-regulation of this response. Alteredresponse patterns after long exposure to As may play a significant role in Astoxicology.

CORRESPONDING AUTHOR: Elizabeth T. Snow, Ph.D., Centrefor Cellular and Molecular Biology, School of Biological andChemical Sciences, Deakin University, 221 Burwood Highway,Burwood VIC 3125 AUSTRALIA


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66

CARCINOGENICITY OF DIMETHYLARSINIC ACID IN RATS

Samuel M. Cohen, M.D., Ph.D., Lora L. Arnold, M.S., University of NebraskaMedical Center; X.C. Le, Ph.D., University of Alberta, Edmonton

Dimethylarsinic acid (DMA) produces an increased incidence of bladdertumors in rats when administered in a two-year bioassay either in the diet or in thedrinking water, with females being more susceptible than males. There is nocarcinogenic effect of DMA administered to mice, and there are no pre-neoplasticchanges in the hamster urinary tract when administered in the diet for 10 weeks. In addition, DMA enhances the incidence of bladder tumors in male ratsadministered after treatment with the bladder carcinogen, N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN). Evidence of urothelial cytotoxicity is presentwithin six hours after administration begins. By seven days, there is a consequentregenerative hyperplasia, as evident by light and scanning electron microscopyand by increased bromodeoxyuridine (BrdU) labeling index. The dose responsefor toxicity and regeneration is the same as the dose response for tumorigenicity. Co-administration of DMA with 2,3-dimercaptopropane-1-sulfonic acid (DMPS)inhibits the toxicity and regeneration. The principal urinary metabolites followingDMA administration at 100 ppm of the diet are DMA and trimethylarsine oxide(TMAO), but dimethylarsinous acid (DMAIII) is present in the urine atconcentrations of approximately 1-5 :M. In vitro, trivalent arsenicals, includingDMAIII, are cytotoxic at micromolar or lower concentrations whereas thepentavalent organic arsenicals are cytotoxic to rat and human urothelial cells atmillimolar concentrations. Assessment of the carcinogenic risk of DMA tohumans must take into account the extraordinary doses required to produce theeffect in rats, the markedly different metabolism of DMA in rats compared tohumans, and the generally low levels to which humans are exposed.


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68

ARSENIC-INDUCED CONGENITAL MALFORMATIONS INGENETICALLY SUSCEPTIBLE FOLATE BINDING PROTEIN-2

KNOCKOUT MICE

1Ofer Spiegelstein, 2Xiufen Lu, 2Chris X. Le, 3Bogdan Wlodarczyk and 1Richard H.Finnell1Center for Environmental and Genetic Medicine, Institute of Biosciences andTechnology, Texas A&M University Health Science Center, Houston, TX;2Department of Public Health Sciences, University of Alberta, Edmonton, Alberta,Canada; 3University of Nebraska Medical Center, Omaha, NE. Arsenic has been long suspected of being a human teratogen, although there iscurrently insufficient and inadequate supportive data to make any definitivejudgments. In addition, the significance of individual genetic differences onpregnancy outcomes following in utero exposure to arsenic is currently unknown. Inorder to better understand the role of intracellular folate transport mechanisms inarsenic-induced neural tube defects, we examined the effect of in utero exposure tosodium arsenate in a genetically altered murine model in which the folate bindingprotein 2 (Folbp2) gene has been inactivated by homologous recombination.Administration of 40 mg/kg sodium arsenate by intraperitoneal injection atgestational days 7½ and 8½, induced exencephaly in 40.6% of Folbp2-/- embryos,compared to 24.0% in wild-type controls. The differences in response frequencieswere further exacerbated when the dams were fed a diet with decreased folatecontent. Under these conditions, exencephaly was observed in 64.0% of Folbp2-/-

embryos, compared with 25.7% in controls. To test whether the differences insusceptibility are due to differences in exposure, we performed a 24-h urinaryspeciation analysis following a 30 mg/kg ip injection of sodium arsenate. The dataindicated that there were no significant differences in excretion of arsenicals betweenthe two genotypes, suggesting that the increased in utero susceptibility of Folbp2-/-

mice to arsenate may not be due to differences in biomethylation and exposure. Weare currently studying the effect of nutritional folic acid intake on arsenatebiotransformation in several folate transport knockout mouse strains.This work was supported in part by grants DE13613, HD35396, ES09106 andES04917


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69

THE REACTIVE OXYGEN SPECIES (ROS) THEORY OF ARSENIC CARCINOGENESIS.

Kirk T. Kitchin, Ph.D., US Environmental Protection Agency; Sarfaraz AhmadPh.D., Mercer University

At this time, there is not a scientific consensus on the mechanisms/modes ofaction for arsenic carcinogenesis. Proposed mechanisms/modes of action for arseniccarcinogenesis include but are not limited to clastogenic effects, mutation, oxidativestress (via ROS and other chemical species), gene amplification, altered DNAmethylation, cell proliferation, promotion of carcinogenesis, effects on theprogression stage, inhibition of DNA repair and interaction with important cellularproteins.

Oxidative stress from arsenic exposure might result either (a) from arsenicspecies such as dimethylarsenic radical and dimethylarsenic peroxy radical, (b) fromrelease of from ferritin (by dimethylarsinous acid (DMA(III)) and dimethylarsinicacid (DMA(V))) or from induction of heme oxygenase (by arsenite), (c) from redoxcycling of trivalent to pentavalent arsenic forms or (d) from ROS such as superoxide,hydrogen peroxide, hydroxy radical or singlet oxygen. Arsenic carcinogenesis mayproceed via hydroxy radical production by the Haber-Weiss reaction.

Various investigators have shown that arsenic exposures increase 8-hydroxy-2'-deoxyguanosine concentrations in mouse urine, rat liver and human skin.Elevations in ROS concentrations can lead to increased 8-hydroxy-2'-deoxyguanosine concentration, single strand breaks in DNA and G-->T mutations inDNA.

Arsenic is a human carcinogen in skin, lung, liver, urinary bladder andkidney. Elucidating the mechanisms/modes of arsenic carcinogenesis wouldcontribute to a more quantitative and scientifically based risk assessment for arsenic,a major world public health problem.(Disclaimer: This is an abstract of a proposed presentation and does not necessarilyreflect EPA policy.)

CORRESPONDING AUTHOR: Kirk T. Kitchin, PhD., DABT,MD-68, Cancer Biology Branch, Environmental Carcinogenesis Division, NHEERL,US EPA, 86 Alexander Drive, Research Triangle Park, NC 27711, USA.


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70

ARSENIC METABOLISM IN EISAI HYPERBILIRUBINEMIC (EHB)RATS: DISTRIBUTION AND EXCRETION IN RELATION TO

TRANSFORMATION

Kazuo T. Suzuki, Ph.D., Takayuki Tomita and Yasumitsu Ogra, Ph.D., GraduateSchool of Pharmaceutical Sciences, Chiba University, Chiba, Japan

Diverse chemical species of arsenic can be taken up by humans throughdietary foods and water. However, the most probable and toxic form of arsenicexposed to humans is arsenite (iAsIII). Arsenite absorbed by the body is taken up bythe liver, and then transformed by consecutive methylation and reduction reactionsto the commonest final urinary metabolite, dimethylated arsenic (DMA). Namely,iAsIII is oxidatively methylated to monomethylarsonic acid (MMAV), and thenreduced to monomethylarsonous acid (MMAIII) for further oxidative methylation todimethylarsinic acid (DMAV). In rats, DMAV is further reduced efficiently todimethylarsinous acid (DMAIII), and then excreted into the bloodstream, whereDMAIII is sequestered by red blood cells (RBCs), resulting in the preferentialaccumulation of arsenic in rats.

During the metabolic transformation of arsenic, substantial amount of iAsIIIinjected intravenously (iv) into rats disappeared from both bloodstream and majororgans, and then reappeared after 6 hr mostly in the RBCs. The arsenic disappearedfrom the bloodstream and major organs was assumed to be excreted into the bile, i.e.,get into the hepato-enteric circulation in the form conjugated with glutathione (GSH)(iAsIII(SG)3) during the metabolic transformation. However, substantial amount ofarsenic also disappeared in EHB rats, where arsenic is not excreted into the bile.Nevertheless, the arsenic accumulating in the RBCs was much higher in EHB rats.Then, the arsenic disappeared during the first 6 hr after the injection was traced andexplained by the distribution in the liver, muscle and other organs, and excretion tourine and bile followed by the later redistribution to and accumulation in the RBCs.It was not confirmed whether the arsenic distributed to organs other than liverredistributes to RBCs after transformation to DMA or in the form of arsenite. MMAis partly excreted into the bile in the GSH-conjugated form, a part of it beingreabsorbed. Further, MMA is partly excreted from the liver into the bloodstream.DMA was not excreted into the bile.

Corresponding author: Kazuo T. Suzuki, Graduate School of PharmaceuticalSciences, Chiba 263-8522, Japan. E-mail: [email protected]


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71

MOLECULAR APPROACHES TO DISSECT ARSENIC-DEPENDENTSIGNALING MECHANIMS

Deanna G. Adams, Ph.D., and Richard R. Vaillancourt, Ph.D., Department ofPharmacology & Toxicology, University of Arizona College of Pharmacy

Recent studies have demonstrated that arsenite activates the family of Mitogen-Activated Protein (MAP) kinases that include c-Jun amino-terminal kinase (JNK),p38 MAPK, and extracellular signal-regulated kinase (ERK). In transfection studiesof HEK293 cells, dominant-negative MEKK3 (MAPK/ERK Kinase Kinase)inhibited arsenite-dependent activation of JNK, suggesting that endogenous MEKK3is involved in arsenite signaling. The objective of this study was to identify andcharacterize kinases that function upstream of MEKK3 in arsenite signaltransduction. We demonstrate that the stress-activated protein kinase, MEKK3, isphosphorylated in vivo and in vitro in response to arsenite and activation of proteinkinase A (PKA). When (His)6FLAG•MEKK3 was expressed in Sf9 insect cells andpurified with Ni-Sepharose, we identified 14-3-3 protein by liquid chromatographyand electrospray tandem mass spectrometry (LC-MS) as co-purifying withrecombinant MEKK3. Since 14-3-3 proteins have been reported to interact withproteins through phosphoserine, we sequenced (His)6FLAG•MEKK3 by LC-MS toidentify phosphorylated amino acids. Of the tryptic peptides sequenced, twoconsisted of amino acids 164-174 and 335-349 and serines 166 and 337 werephosphorylated within the respective peptides. Phosphorylation of both serines waslocalized within two consensus PKA phosphorylation sites, RXX(S/T). Phospho-specific antibodies were developed to recognize phosphorylated serine 166 ofMEKK3. These antibodies detected phosphorylation of MEKK3 at serine 166 inresponse to arsenite and activation of PKA with forskolin. These results suggest thatarsenite regulates MEKK3 phosphorylation through a mechanism that involves PKA.

CORRESPONDING AUTHOR: Richard R. Vaillancourt, Ph.D., Department ofPharmacology & Toxicology, University of Arizona College of Pharmacy, Tucson,AZ 85721-0207, USA


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INCORPORATING MECHANISTIC INSIGHTS IN A PBPK MODELFOR ARSENIC

Elaina M. Kenyon, Michael F. Hughes, Marina V. Evans, David J. Thomas, U.S.EPA; Miroslav Styblo, University of North Carolina; Michael Easterling, AnalyticalSciences, Inc.

A physiologically based pharmacokinetic (PBPK) model for arsenic providesan integrated framework for addressing issues related to risk assessment, as well asbeing a tool for hypothesis testing and experimental design. This is because a PBPKmodel defines the relationship between external exposure and an internal measure of(biologically effective) dose. The arsenic PBPK model is necessarily complexbecause of the existence of multiple biologically-active forms and uncertaintyconcerning their roles in producing toxic effects. Functionally, for arsenic thisrequires a minimum of 4 submodels linked by reduction/oxidation and methylationas well as incorporation of urinary excretion for each metabolite and tissue bindingfor certain trivalent forms. This is necessary since the availability of arsenate,arsenite and methylated forms for tissue interactions is a balance between rates ofexcretion, binding, redox cycling and methylation. Our current PBPK modelstructure will be reviewed in this presentation and unique mechanistic features,together with their experimental basis, will be highlighted. These includedimethylarsinic acid accumulation in lung, inhibition of the second methylation stepby arsenite, and assumptions regarding transport and partitioning into tissues. Ourmodeling experiments and sensitivity analysis have also suggested several importantlines of research. Critical information to gather in human populations include dataon differences in methylation capacity, improved temporal data on exposure andurinary excretion of arsenic metabolites, and speciated tissue distribution data fromautopsy samples. [This abstract does not reflect EPA policy.]

CORRESPONDING AUTHOR: Elaina M. Kenyon, Ph.D., U.S. EPA,NHEERL/ETD/PKB, MD-74, Research Triangle Park, NC 27711, USA.


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74

ARSENIC, DRINKING WATER, AND HEALTH: A REVIEW

Kenneth G. Brown, Ph.D., KBinc; Gilbert L. Ross, M.D., American Council onScience and Health

This presentation reviews issues and sources of uncertainty related toassessment of health risks from arsenic in drinking water in the U.S. and how theyhave arisen. It also chronicles some of the major arsenic-related regulatory activitiesof U.S. EPA. EPA is directed by the Safe Drinking Water Act (SDWA) of 1974 toestablish national standards for contaminants in public drinking-water supplies.Almost coincidental with an EPA draft risk assessment in 1984 related to skincancer, new epidemiological and other scientific articles began to proliferate, linkingarsenic in drinking water to cancer at internal sites and to additional non-cancereffects, and reporting results related to biomarkers of exposure and mode-of-action.It also came to light that arsenic toxicity from drinking water was of severe-to-epidemic proportions in several regions of the world, fueling further concern forpublic health in the U.S. EPA and stakeholders were motivated to fund workshopsand further research, producing still more scientific reports. Definitive resolution ofsome risk-related controversies remained stymied, however, by limitations ofobservational data and incomplete knowledge of complex issues related to kineticsand mechanisms of toxicity. EPA finally commissioned the National ResearchCouncil to evaluate the scientific evidence, and set a "final" rule of 10 :g/L inJanuary, 2001. A nine-month delay followed the appointment of the new EPAadministrator, however, to have three committees reconsider the evidence on healthrisks, economics, and cost-benefit, before the "final" rule became the final rule.

CORRESPONDING AUTHOR: Kenneth G. Brown, 511 Palafox Drive, ChapelHill, NC 27516, USA.


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75

PROGRESS TOWARD A BIOLOGICALLY REALISTIC CANCER RISKASSESSMENT FOR INORGANIC ARSENIC

Harvey J. Clewell, ENVIRON Int’l Corp.; Melvin E. Andersen, Colorado StateUniversity; Janice W. Yager, EPRI.

Trivalent arsenic species bind avidly to cellular proteins, especially thosecontaining vicinal dithiols, disrupting cellular function. For an arsenic mode ofaction involving inhibition of critical cellular proteins, a sharp transition can beexpected from concentrations of arsenic with little effect to those at whichinhibition of one or more key cellular proteins becomes sufficient to causetoxicity or carcinogenicity. However, nutritional, pharmacokinetic, and geneticfactors also alter the quantitative relationship between drinking waterconcentrations of arsenic and the expression of specific tissue responses acrossindividuals. Physiologically based pharmacokinetic and biologically based dose-response modeling will play a crucial role in integrating dosimetric andmechanistic information into a quantitative framework suitable for conducting ascientifically plausible risk assessment for arsenic. These same modelingapproaches can also be used in the context of Monte Carlo analysis to evaluate theimpact of inter-individual variability on the aggregate dose-response for thepopulation. This presentation will reviews recent progress, ongoing efforts, andneeded research to (1) characterize the dose-response for the cellular effects ofarsenic, (2) establish the metabolism and distribution of the various arsenicspecies at high, tumorigenic and lower environmental exposures, and (3) developbiologically based dose-response modeling approaches for linking tissue exposureto one or more of the arsenic species with the eventual production of tumors. Thepotential for using a biologically based dose-response model to conduct aquantitative, nonlinear cancer risk assessment for arsenic that considers humaninter-individual variability will be discussed.

CORRESPONDING AUTHOR: Harvey Clewell, ENVIRON Int’l Corp., 602E. Georgia Ave., Ruston, LA 71270, USA.


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77

NATURAL HISTORY OF ARSENICOSIS IN AN ARSENIC ENDEMICAREA OF WEST BENGAL, INDIA : A 5 YEAR FOLLOW UP STUDY.

DN Guha Mazumder1, M.D., FAMS, Nilima Ghose1, MBBS, Kunal Mazumder1,MD, Allan H Smith2, PhD, Amal K Santra1, PhD, Sarbari Lahiri1, PhD, & SubhankarDas1, MSc

1Institute of Post Graduate Medical Education & Research, Kolkata, India2University of California, Berkeley, USA

Introduction:

Information on natural history of chronic arsenic toxicity following drinking As freewater is scanty. Medical treatment of arsenicosis to modify the health effects, isunsatisfactory. Result of long term intake of arsenic free water in the affected peoplein an Arsenic endemic area need to be fully ascertained to understand the effect ofintervention programme of providing safe water to the affected community. A cohortfollow up study was therefore conducted on 1074 people in the year 2000, 5 yearsafter initial clinical epidemiological study carried out in the year 1995 with pasthistory of drinking safe (As level ≤ 0.05 mg) (n=451) and unsafe water (As level >0.05 mg/L) (n=623).

Inspite of availability of safe water 568 out of 623 people were found to be takingsafe water (As level < 0.05 mg/L). In the previous study 217 (38.2%) had skin lesion(Pigmentation, Keratosis or both) out of which 18 people died. In the follow up study47 people (8.27%) had new appearance of skin lesion. Out of 199 people whose skinlesions were reexamined, the lesions cleared in 40 (20.1%), decreased in 59 (29.6%),remained same in 95 (47.7%) and increased in 5 (2.5%). Urine arsenic was measuredin 474 i.e. 83.4% of participants out of which 156 i.e. 32.9% had urine arsenic level≤ 50 :gm/L and 318 i.e. 67.1% had urine arsenic level > 50 mg/L. It was intriguingto note that 67% of participants apparently taking safe water at present showed urinearsenic > 50 mg/L, indicating exposure of arsenic from other sources besides waterin the surveyed area. Some study indicate that food may be another source.

Major causes of morbidity and mortality in the previously arsenic exposed populationwere chronic lung disease, cerevrovascular accident and various cancers.

There was significant difference in morbidity and mortality in people having historyof drinking unsafe water compared to the control population studied. Detail data willbe presented in the conference.

Corresponding Author : Dr. DN Guha Mazumder, Instt. Post. Grad. Med. Edun &Res., 244, AJC Bose Road, Kolkata – 700 020. India. Email- [email protected]


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78

SAHA'S GRADING OF ARSENICOSIS PROGRESSION AND PATIENTTREATMENT

Kshitish C. Saha, MD, DTM&H, D.Dermat.Ex Professor and Head of Dermatology, The School of Tropical Medicine, KolkataWest Bengal, IndiaAbstract:

ARSENICOSIS in West Bengal, India and Bangladesh was discovered by theauthor in 1982 and 1984 respectively. Since 1983, periodical field survey showedincreasing severity of ARSENICOSIS. The disease due to ARSENICOSIS wasconfirmed by high arsenic level in consumed water, urine, nails, hair and skin scales.The arsenic content was initially estimated by silver diethyl dithio carbazine method atthe School of Tropical Medicine and much later by flow injection hydride generationatomic absorption spectrometry method at the School of Environmental Studies,Jadavpur University, Kolkata, India.

According to severity, progression of ARSENICOSIS has been classified by theauthor into 4 stages, 7 grades and 20 sub-grades. The 4 stages are I) Pre-clinical, II)Clinical, III) Complication and IV) Malignancy. Each stage is further graded as follows.Pre-clinical (stage I) is graded 0 with 2 sub-grades; 0a (labile or blood phase) and 0b(stable or tissue phase). Clinical stage (stage II) has been subdivided to four grades, 1)Melanosis 2) Spotted keratosis on palms or soles, 3) Diffuse keratosis on palms andsoles and 4) Dorsal keratosis. Each of the four grades has been further subdivided intothree sub-grades, a, b, and c according to severity. Complications (stage III) andMalignancy (stages 1V) are graded 5 and 6 respectively; each of the grades has beenfurther subdivided to a, b, and c.

The features of different sub-grades are as follows, Diffuse Melanosis on palms(1a), Spotted Melanosis on trunk (1b), Generalized Melanosis (1c), Number of Keratoticnodules 0-6 (2a), Number of Keratotic nodules more than 6 (2b), Large Keratoticnodules (2c), Diffuse keratosis on palms or soles (3a), Diffuse keratosis on both palmsand soles (3b), Diffuse keratosis complete on whole palms and soles (3c), Nodularlesions on hands or feet (4a), Nodular lesions on hands and feet (4b), Nodular lesions onhands and feet along with extension of keratosis all over the body (4c), Palpable liver(5a), Jaundice (5b), Ascitis (5c), Malignancy with single lesion (6a), Malignancy havingtwo lesions (6b), and Malignancy having more than two lesions (6c).

The various stages of ARSENICOSIS can be clinically treated as follows. Grade0 can be eliminated by replacing arsenic contaminated with arsenic free water. Alsoother treatment is applied on the patients of advanced grades along with supply ofarsenic free water. The chelating agent, dimercapto propane sulphonate (DMPS), therapyis carried out at grade 2b onwards; the complication may be prevented however, there islittle improvement of Keratosis. The prognosis of grades 5b onwards is poor. At thestage of malignancy, i.e. stage 4 (grades 6a, 6b, and 6c), surgical removal can only helppatients of grade 6a and 6b provided glands are not affected.

Such differentiation of various stages of ARSENICOSIS is helpful to detectasymptomatic cases in pre-clinical or sub-clinical phase and to find the severity of thedisease in order to prevent its further progress to complication and malignancy stages.Corresponding Author: Dr Kshitish CSaha, MD, DTM&H, D. Dermat.Ex. Professor and Head of Dermatology The School of Tropical Medicine,CalcuttaEC-21, Sector-1, Salt-Lake City,

Calcutta- 700064, West Bengal, India.Ph-91-33-337-5090 and 91-33-241-3023E mail [email protected], [email protected]


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79

UNICEF AND ARSENIC MITIGATION A REPORT OF THE THIRD PHASE WORK IN BANGLADESH

Since UNICEF supported its long term counterpart, the Department ofPublic Health Engineering, to conduct the first and so far largest national randomsurvey for arsenic contamination in Bangladesh between 1996 -1998, theorganisation has used every available resource to work to develop and implementarsenic mitigation activities.

While these efforts center on Bangladesh because that is by far where themost widespread and severe contamination exists by today’s understanding, theorganisation is also leading efforts in other countries where arsenic has beendiscovered. Mitigation programmes are also being supported in Nepal, Cambodia,India, Vietnam, Thailand and China. Using its global reach and experience, theorganisation is able to quickly share successes and experiences not only from andbetween those countries where mitigation projects are being implemented, butalso from its headquarters where new knowledge and ideas are being transmittedfrequently to the field. Thus a global sized “learning by doing” is taking place.

In Bangladesh, the magnitude of the task and the consequent size of theeffort needed, have being growing rapidly as new understanding becomesavailable with regard to the consequences of not treating this problem as a raceagainst time. For example the Columbia University discovered in its study areathat over 50% of the contaminated hand pumps had actually only been installedfor less than 5 years. If this is indicative of the other hand pumps in the countrythen this could well be an explanation as to why the number of arsencicosispatients is not yet in the hundreds of thousands as might be expected . It mightalso mean that perhaps the programme is in a window of opportunity now toprevent those many thousands of cases from occurring; but certainly with no timeto lose.

UNICEf’s responsibility has been growing since the first random nationalsurvey. Work has been developed in four phases so far, as ten per cent of thenations upazilas have been entrusted to the organisation in partnership withDPHE, most of these being in the “hot spot” upazilas. The first phase was therandom national survey. The second was the five upazila action research project.The third phase was a additional fifteen upazila expansion and the fourth phasewill be implemented in 2002, a further 25 upazilas making a project area of 45upazilas in all.

So far over 450,000 tube wells have been tested by the UNICEF-DPHEProject work. In 2002 another 500,000 will be tested making almost one millionin all. This work has discovered hundreds of villages that have no safe source atall. More than 1,600 new arsenicosis patients have been diagnosed just in thethird phase upazilas. In addition to the testing programme, the project must divertsome resources and ingenuity to helping people to obtain a safe water source; foruntil all people have access to safe water the job will not be complete.

Author: Colin Davis, UNICEF: [email protected]


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THE WORLD HEALTH ORGANIZATION NORMATIVE ROLES INMITIGATING HEALTH IMPACTS OF ARSENIC IN SOUTH EAST ASIA

REGION

Deoraj Caussy, Ph.D., Evidence for Information and Policy, World HealthOrganization, Office of the South East Asia Region.

Ground water contamination, in excess of the World Health Organization (WHO)guideline value of 0.01 mg/L, has been observed in many parts of the worldincluding India, Bangladesh, Thailand, Myanmar, Nepal, China, Taiwan andVietnam among others. In the South East Asia Region of WHO, it is currentlyestimated that about 30 million persons may have been exposed to contaminatedground water at various concentrations of arsenic and almost a quarter of a millionexposed subjects are already showing overt symptoms of chronic arsenicpoisoning. A review of the epidemiological data shows that there is a need forinternationally accepted criteria based on evidence in the following areas:Exposure assessment, case-definition and case management. This paper reviewsthe existing epidemiological evidence for standard case definition andmanagement and presents WHO strategic goals to meet these objectives. Effortsare on the way to define a regional protocol for case definition and casemanagement. The availability of such guidelines will remove the wide variationbetween studies describing prevalence rates or efficacy of a medical treatment andensure consistency of training for health care workers.

CORRESPONDING AUTHOR: Deoraj Caussy, Ph.D., Department of Evidencefor Information and Policy, World Health Organization, Office of the South EastAsia, World Health House, Ring Road, New Delhi 110 002, INDIA


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81

ONLY PAINTING TUBEWELLS RED OR GREEN, DOES NOT HELPARSENICOSIS PATIENTS

Quazi Quamruzzaman, FRCS, Mahmuder Rahman, FRCP, M. A. Salam, Ph.D.,A. I. Joarder, MBBS, Dip.Orth, M. Shahjahan, MBBS Dip.IH, S. U. Mollah,MBBS, Dhaka Community Hospital

The problem of the arsenic contamination of hand-pump shallowtubewells in Bangladesh became known in 1993. As 97% of the population drinktubewell water, various studies have predicted that nearly 85 million people are atrisk from arsenic poisoning.

The experience of working at the field level in Bangladesh shows that thepresent mitigation programmes may not be effective due to faulty design. Theseprogrammes are mainly centred on identifying contaminated tubewells by fieldtest kits and then painting the tubewell red or green for unsafe or safe. Someprogrammes include models of alternative water supply options and some includefield level patient identification with the provision of vitamins and ointments forlesions.

The Dhaka Community Hospital experience of treating hundreds ofaffected patients demonstrates that investigation, diagnosis, appropriate treatment,physical and socio-economic rehabilitation and cost analysis should be essentialcomponents of any arsenic mitigation programme.

The current emphasis of programmes and funds on safe water supply only,ignores the human dimension of the arsenic problem. Safe water supplies areessential but the management of those already affected by arsenicosis should bethe main focus of any arsenic mitigation programme.

CORRESPONDING AUTHOR: Quazi Quamruzzaman, FRCS, DhakaCommunity Hospital, 190/1 Wireless Railgate, Boro Maghbazaar, Dhaka 1219,Bangladesh.


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83

WEB SITE ARSENIC REMEDIATION DATABASE OF > 50 OPTIONS

Susan Murcott, Massachusetts Institute of Technology

Knowledge of the extent of arsenic occurrence and its effect on publichealth has not kept pace with remediation efforts. Arsenic contamination wasdiscovered in West Bengal in the early 1980s and in neighboring Bangladesh inthe early 1990s. Ten to twenty years have passed without adequate solutionsbecoming generally available. This gap – between knowledge and action toprovide safe, alternatives to contaminated tubewells - has real-life impacts,especially for the poor in West Bengal, Bangladesh and other arsenic-impactedcountries.

The first step to action is to know the alternatives. To date, the WorldWide Web has not been used to its potential to provide and exchange informationspecifically about arsenic remediation options. To help remedy this informationgap, this paper begins by reviewing the major Web sites that cover multiplearsenic remediation options, then it presents the author’s arsenic remediationWeb site: http://web.mit.edu/murcott/www/arsenic. This site discusses theuniverse of arsenic remediation methods, beginning with alternatives tocontaminated tubewells, then covering over 50 tubewell treatment technologies.Applying a common template, each technology in the database is described indetail, including its performance, the analytic method used to determineperformance, and the sites of lab, pilot, or full-scale tests. All tubewell treatmentoptions are categorized according to the dominant treatment process: oxidation,coagulation/precipitation, filtration, adsorption, ion exchange, membraneprocesses, biological and “other,” so that similar technologies and approaches canbe compared. We learn what equipment is needed, step-by-step procedures usedto carry out lab and field tests, capital and O&M costs, sludge issues, and whichoptions are promoted by which agencies, companies, and academic institutions.Links and email addresses are given wherever possible. Finally, publishedreferences are listed. This Web site serves as a knowledge base and educationaltool. Hopefully, this information will facilitate speedier mitigation efforts andactions.

CORRESPONDING AUTHOR: Susan Murcott, Department of Civil andEnvironmental Engineering, Massachusetts Institute of Technology, 77Massachusetts Avenue, 1-138, Cambridge, Ma. 02139 Email: [email protected]


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84

ARSENIC MITIGATION: CHALLENGES OF BANGLADESH

Chowdhury M. Ahmed, Ministry of Local Government Rural Development &Co-operatives, Government of the Peoples Republic of Bangladesh.

Bangladesh has been facing multifarious challenges in addressing theproblem of arsenic contamination of ground water, which has become a publichealth problem of catastrophic proportion.

Lack of adequate knowledge about the cause, nature and scale of theproblem made the designing of mitigation measures a difficult job. Drinkingwater supply in Bangladesh, particularly in rural areas, is predominantly based onan estimated 8-9 million individual tube wells, a substantial portion of which isbelieved to be contaminated with arsenic above acceptable limits.

The intricate distribution pattern of arsenic contaminated aquifers and thespatial variability of arsenic concentration from well to well have made testing ofeach and every tube well in potential arsenic contaminated areas essential.However, the scarcity of testing facilities including adequate field test kits withrequired efficiency has made this task even more complicated. But the toughestchallenge comes in providing safe drinking water supply in affected areas.Alternative water sources are not always easy to identify as alternative options,may be expensive or not yet proven as safe and effective.

Absence of any known treatment for arsenicosis patients has made patientmanagement a delicate business. Lack of established patient identification andmanagement protocols make the situation more awkward. Creating socialawareness and building necessary capacity at various levels to tackle the impact ofthe problem are demanding tasks.

Developing an appropriate institutional arrangement with redefined role ofvarious stakeholders for sustainable management of the problem is also a trickyjob, given the differing interest and orientation of various stakeholders.

CORESPONDING AUTHOR: Chowdhury Mufad Ahmed, Coordinator, ArsenicPolicy Support Unit and Senior Assistant Secretary, Local Government Division,Ministry of Local Government Rural Development & Co-operatives, Governmentof the Peoples Republic of Bangladesh. Bangladesh Secretariat, Dhaka,Bangladesh.


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85

INVESTIGATION OF ARSENIC REMOVING TECHNOLOGIES FORDRINKING WATER IN VIETNAM

Viet H. Pham, Ph.D., Con H. Tran, Ph.D., Ha T. Cao, Ph.D., Hanoi University of Science;Michael Berg, M.Sc., Walter Giger, Ph.D., Roland Schertenleib, Swiss Federal Institute forEnvironmental Science and Technology

The arsenic contamination in groundwater was discovered in many areas ofVietnam. It is a challenge to spur scientists and technologists to find out suitabletechnologies and equipments for arsenic removal from drinking water. The first thing wehave investigated focused on arsenic removal for supply water of main water treatmentplants in cities. The research methodology was based on the existing water treatmentprocess of water treatment plants and made advantages of their available technology. Therewere investigations on adsorption kinetics of As (III) and As (V) species onto iron (III)hydroxide formed during the aeration step. The obtaained results showed that adsorptionability of arsenate was more better than arsenite species and active chlorine using fordisinfection could totally oxidize arsenite (III) into arsenate (V). The minimal amount ofiron in groundwater needed for 0.5 mg/L arsenate removal was found out approximate 5mg/L, while those for arsenite was more than 25 mg/L. The investigation suggested that itshould be changed disinfection step from the end point of water treatment process to the siteof coagulation or after aeration step.

The above-mentioned arsenic removal technology could not be applied for familieswhere they used to take arsenic contaminated groundwater directly from tubewells asdrinking water. At present, there are millions of people using the contaminated groundwater.To save people from potential arsenic infection, we suggested to use adsorption-columnsfilled by arsenic removing materials such as denaturated oxidic iron’s ores (such asLimonite and Laterite). Laterite and Limonite (local people called as Bee-Nest-Stone andVermilion) are abundant minerals in Northern Vietnam. Many authors affirmed theadsorption ability of iron oxide and iron hydroxide but there was no serious investigationon laterite and limonite.

The iron ores were firstly dried, grained and sieved to particles with size of 0.1-1.0mm. Then they were thermally pretreated at 500, 700, 800 and 900OC in order to removewater-trace and vapor components including sublimate arsenous component. X-raydiffraction measurement of limonite showed that the iron oxide (α-Fe2O3) composition wasnot changed after calcination even at 900oC. But Fe2O3.H2O species were not almost existentat 700oC. All kinds of the pretreated samples and the untreated samples (it was only driedat 150oC) were tested for their arsenic adsorption ability. It was interesting that the untreatedlimonite and laterite were of higher adsorption ability than the treated ones. The Langmuiradsorption isotherms were determined for kinetic investigation of adsorption process. Themaximal adsorption capacity of limonite was approximately 900 mg/kg for As(V) and 500mg/kg for As(III) based on its equilibration with aquous solutions of arsenic concentrationslower than 1000 ppb.

An important aspect of this research was that full adsorbed sorbent could be totallyregenerated simply by using sodium hydroxide solution. Beside that, it showed clearly thatthe water after arsenic removal by those ores were not containing secondary pollutionsubstances.CORRESPONDING AUTHOR: Viet H. Pham, Ph.D., Centre for EnvironmentalChemistry, Hanoi University of Science, 334 Nguyen Trai Road, Thanh Xuan District,Hanoi, Vietnam


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86

REMOVING ARSENIC FROM DRINKING WATER: A BRIEF REVIEWOF SOME LESSONS LEARNED AND GAPS ARISED IN CHILEAN

WATER UTILITIES.

Ana María Sancha F., Associate Professor, Universidad de Chile

Theoretically, Arsenic removal from water can be achieved by using differenttechnologies. Application at full scale of each one might not be as successful as atlaboratory tests. The difference between the laboratory and full scale performancesmay reflect the control over different variables involved in the Arsenic removalproccess.At full scale some variables are difficult to control and these may interferein the removal process. These interferences may not be detected when working atlaboratory tests with analito (As) solutions in distilled water.

The selection of the best available technology for Arsenic removal should bebased on some key factors, such as: removal goals,quality of the water matrix, waterquantity, skill operator requirements, operational water treatment costs, arsenicspeciation,availability of analytical methods ,sludge management, and others.

Some of these issues may play an important role in the feasability ofArsenic removal practices and therefore must be considered and assesed before theselection of any Arsenic removal technology.Small water utilities may face morechallenges than larger systems.The situation for family systems is even worst.

This paper addresses a critical review of some of this issues and the lessonslearned about Arsenic removal in Chilean water utilities in the last 30 years.Solutionsfor an As- water-dependant society should be not so hard to find when experienceand creative knowledge are used.

CORRESPONDING AUTHOR:Ana María Sancha, División de Recursos Hídricosy Medio Ambiente, Facultad de Ciencias Físicas y Matemáticas, Universidad deChile, P.O.Box 228/3 Santiago, Chile. e-mail:amsancha @ing.uchile.cl


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87

ARSENIC REMOVAL TECHNOLOGIES IN THE FINAL RULE

Jeffrey B. Kempic & Amit Kapadia, United States Environmental Protection Agency

In developing drinking water regulations, the United States EnvironmentalProtection Agency (EPA) is required to identify technologies that can be used tomeet the maximum contaminant level (MCL). EPA is required to identify treatmenttechnologies for large systems (called best available technologies or BATs) and smallsystems (called small system compliance technologies) that can be used by systemsto meet the MCL. EPA evaluated the available treatment technologies and developedcost estimates for thirteen treatment technology/residuals management combinations.These findings were summarized in the December 2000 support document entitled“Technologies and Costs for Removal of Arsenic from Drinking Water.”

The treatment technology unit cost estimates are one component used todevelop national costs for the arsenic rule. Other major components includeoccurrence projections, system categorization, and a compliance forecast (decisiontree). The annual compliance cost estimate for systems to meet the 10 µg/L standardis just under $200 Million per year. This analysis is described in the December 2000support document entitled “Arsenic in Drinking Water Rule Economic Analysis.”

This paper will provide an overview of the process EPA used to identifytreatment technology/residuals management combinations for the final rule. It willalso discuss some additional technologies for arsenic removal that may play asignificant role in compliance with the MCL. The performance data for some of thesetechnologies became available after the January 22, 2001 final rule.


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88

DISPOSAL OF WASTES RESULTING FROM ARSENIC REMOVAL PROCESSES

Michael J. MacPhee, Ph.D., McGuire Environmental Consultants, Inc.; John T. Novak, Ph.D., Virginia Tech;Rodney N. Mutter, P.E., EE&T, Inc.

The new USEPA drinking water arsenic MCL of 10 ug/L will requireimproved arsenic treatment at some locations and new treatment plants at manyothers. Until recently, little attention has been given to the issue of management ofresiduals from arsenic removal processes. This research showed that liquid residualsgenerated by some treatment processes such as ion exchange (IX) and regenerableactivated alumina (AA) will have problems meeting state and local discharge limits.

The research demonstrated that storage of semi-liquid or solid residualscontaining arsenic for even brief periods could result in re-release of arsenic to theenvironment due to reducing conditions. Such conditions occur in landfills and otherplaces where residuals accumulate, including settling basins and clarifiers withinwater treatment plants.

Release of arsenic that occurred under reducing conditions was typically notpredicted by the TCLP test. In fact, all aged residuals had arsenic TCLP levels ofless than 10 times the 5 mg/L limit, but still leached appreciable quantities of arsenic.When the same residuals were evaluated using California WET toxicity leaching test,several were close to or exceeded the 5 mg/L limit for that state. This suggests thatutilities using coagulation (or perhaps even iron removal processes) for arsenicremoval may generate residuals that would be deemed hazardous in California. Sucha situation would have major cost and operational implications for affected utilities,and may be a key driver for arsenic treatment process selection. The status of othertypes of water treatment residuals with respect to meeting the Ca WET test is notwell known. Toxicity characterization could also have an important national costimpact if USEPA proceeds with a review of the TCLP and makes the test moreaggressive for arsenic leaching.

CORRESPONDING AUTHOR: Michael J. MacPhee, Ph.D., McGuireEnvironmental Consultants, Inc., 1620 Market Street, Suite 3E, Denver, CO 80202, USA.


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89

DEVELOPMENT OF A LOW-WASTE TECHNOLOGY FOR ARSENICREMOVAL FROM WATER

József Hlavay, D.Sc., Ph.D., Mónika Szilvási, Klára Polyák, Ph.D., University ofVeszprém; János Molnár, Kornél Gruber, WEDECO Ltd.; Pál Medgyesi, FlóraBende, Makó Water Works; Márta Hódi, Ph.D., Hydra Ltd.

The purification of drinking water containing inorganic arsenic compoundscauses important problems in Hungary. The new regulation of European Union setsa limit of 10 mg As/L. Today more than 400 settlements are served with tap watercontaining higher arsenic content in the country. Arsenic ions are accompanied byhigh amounts of ammonium-, Fe-, and Mn-ions, humic acids (about 10-15 mg/L),dissolved gases, and has high temperature, >30 /C. This contamination arises fromnatural leaching of arsenic rocks by the percolating water. To keep this new standarda huge effort has to be done.

New low-waste technology was developed by combination of ion exchange andadsorption methods. It is appropriate for selective removal of ammonium, iron,manganese and arsenic ions, as well as humic acids from drinking water. Processeswere applied in laboratory and field experiments. Natural ion exchangers andadsorbents were used for the experimental work as sodium-form naturalclinoptilolite, (Na-Cli), manganese-form natural clinoptilolite, (Mn-Cli), granulatedactivated carbon, (GAC), and granulated Al2O3/Fe(OH)3. Optimal exhaustion-regeneration cycles were estimated and pilot-plant set-up was designed.

CORRESPONDING AUTHOR: József Hlavay, D.Sc., PhD., Department of Earthand Environmental Sciences, University of Veszprém, 8201 Veszprém, P. O. Box158, Hungary, e-mail: [email protected]


SPEAKERS' ABSTRACTS

91

REPORTS FROM SOME EPA OFFICES DEALING WITH ARSENICISSUES

Charles O. Abernathy1, Erik Winchester1, Andrew E. Schulman1, John B. Bennett1,T. McMahon2 and Peter Grevatt3. Office of Water (OW)1, Office of PesticidesProgram (OPP)2 and Offices of Solid Waste (OSWER)3, US EPA, Washington, DC

Arsenic (As) exposure, both natural and anthropomorphic, has affected manypeople in the US and the world. Since As occurs in the water, soil and food and isused in pesticides and industry, different Offices in the EPA are currently workingon various aspects of this problem. After considering the health effects, practicalquantitation limits, technical feasibility and cost benefits of As, the EPA promulgateda final rule on As in drinking water on January 22, 2001. The EPA had the healtheffects, treatment costs and cost benefits reviewed and on October, 30, 2001, EPAannounced that there would be no delay in implementation of the new As rule. OWis also pursuing a more robust benefits model(s), which accounts age-specific andphase-in of risk reductions over time following reductions in As exposure. It is alsoin the process of developing a Human Health Criterion (HHC) for As. One arearequiring an new analysis is the bioaccumulation factor (BAF) for As. Although itmay bioaccumulate, primarily as organoarsenicals, in various fish and shellfish,many of the forms seem to pose little or no health risks. Thus, the EPA isconsidering the level of accumulation of various arsenicals versus the potentialtoxicity of the those forms to derive a BAF for use in the As HHC. OPP held aFIFRA Science Advisory Panel meeting in October, 2001 to consider hazard andexposure issues related to potential risks from exposure to the inorganic As inchromated copper arsenate (CCA)-treated lumber. The recommendations of the Panelwill be considered in completing the risk assessment currently being conducted forinorganic As as a component of CCA-treated lumber. In addition, As is among themost frequently identified contaminants at waste areas, including mining sites andpesticide formulation facilities. OSWER/EPA is working in partnership with otherfederal agencies and the private sector to better understand the bioavailability of Asin the contaminated soil at these sites.(The opinions expressed in this abstract arethose of the authors and do not necessarily represent the opinions or policies of theUS EPA.)

CORRESPONDING AUTHOR: Charles O. Abernathy, HECD (4304T), US EPA,1200 Pennsylvania Ave, NW, Washington, DC 20460, USA

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