Arsenico Em Paracatu

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Arsenic Mobility in Sediments from Paracatu River Basin, MG,Brazil

Patrı ´cia Sueli Rezende • Letı́ cia Malta Costa •

Clá udia Carvalhinho Windmo ¨ller

Received: 18 September 2014 / Accepted: 27 January 2015 Springer Science+Business Media New York 2015

Abstract Paracatu River Basin, Minas Gerais, Brazil,houses long areas of irrigated agriculture and gold-, lead-,and zinc-mining activities. This region has a prevalence of sulde minerals and a natural occurrence of high levels of arsenopyrite. In this work, surface water, groundwater,sediments and local vegetable samples were collected inOctober 2010 and November 2011 and were analyzed toevaluate arsenic (As) distribution, mobility, and transportin these environmental compartments. All sediment sam-ples (738–2,750 mg kg - 1 ) and 37 % of the water samples[less than the limit of detection (LOD) to 110 l g L - 1 ]from the rivers and streams of Paracatu had As concen-trations greater than the quality standards established bynational and international environmental organizations(5.9 mg kg - 1 for sediments and 10 l g L - 1 for water).Most vegetable samples had As concentrations within thenormal range for plants (lower than the LOD to120 mg kg - 1 ). A correlation among As concentrations inwater, sediment, and vegetable samples was veried.

The Agency for Toxic Substances and Disease Registry(ATSDR) from the Department of Health of the UnitedStates biannually classies the most dangerous substancesto human health. Since 1997, As is at the top of the list(Assis 2010 ; ATSDR 2011 ; World Heath Organization(WHO) 2010 ). As can be found in the environment in or-ganic and inorganic forms (Maity et al. 2004 ; Assis 2006 ;Baig et al. 2009 ; Tuzen et al. 2010 ). It is distributed inseveral chemical forms and may transform itself throughthe action of microorganisms, through changes in geo-chemical conditions, or through involvement in otherequilibriums that are affected by the presence of other ionsor compounds in the environment (such as Fe 3 ? , S2 - , andiron [Fe] oxi-hydroxides) (Assis 2006 ). The inorganicforms are more toxic than organic As species becausearsenite (AsO 3

3 - ) is approximately 100 times more toxicthan arsenate (AsO 4

3 - ) (Tuzen et al. 2010 ).Approximately 99 % of As in the environment is asso-

ciated with rocks and minerals. It is present in [ 200 min-erals with approximately 60 % as arsenate; 20 % asarsenosuldes associated with Fe, lead, copper, silver (Ag),and thallium; and the remainder as arsenites, arsenides,oxide, and elementary As (Mandal and Suzuki 2002 ; Assis2006). As has a high afnity with sulfur, which results in alow mobility to other environmental compartments as aconstituent of sulde minerals (Mandal and Suzuki 2002 ;Figueiredo 2010 ). Its most common mineral is arsenopyrite,which is usually associated with gold (Au) and Ag miner-alizations (Mandal and Suzuki 2002 ; Andrade 2007 ). As isliberated from mineralized rocks when arsenopyrite is oxi-dized by oxygen (O 2 ) through biotic or abiotic processes(Rodrigues 2008 ). Mining activities are the main anthro-pogenic sources of As release to the environment (Assis2006 ). The exposition of the source material favors theweathering process, thus leading to sulde oxidation, which

Electronic supplementary material The online version of thisarticle (doi: 10.1007/s00244-015-0134-y ) contains supplementarymaterial, which is available to authorized users.

P. S. Rezende ( & ) L. M. Costa C. C. Windmo¨ller

Departamento de Quı ´mica, ICEx, UFMG - Universidade Federalde Minas Gerais, Belo Horizonte, MG, Brazile-mail: [email protected]

L. M. Costae-mail: [email protected]

C. C. Windmo¨ llere-mail: [email protected]

P. S. RezendeDepartamento de Quı ´mica, CEFET-MG - Centro Federal deEducaça˜o Tecnolo´gica de Minas Gerais, Belo Horizonte, MG,Brazil

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Arch Environ Contam ToxicolDOI 10.1007/s00244-015-0134-y

http://dx.doi.org/10.1007/s00244-015-0134-yhttp://dx.doi.org/10.1007/s00244-015-0134-y


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may generate sulfuric acid (mine acid draining) by way of aseries of reactions (Figueiredo 2010 ; Andrade et al. 2012 ).Some factors, such as grain size distribution, low pH values,heat, and exposure to water and oxygen, may favor mineraloxidation (Andrade et al. 2008 ) with the consequent releaseof As to the soil solution and watercourse.

Arsenopyrite oxidation creates As oxyanions, which are

found in the form of arsenious acid (H 3 AsO 3 ), As(H 3 AsO 4 ), and their deprotonated species—H 2 AsO 4 - ,HAsO 4

2 - , AsO 43 - (arsenate ion), H 2 AsO 3 - , HAsO 3

2 - ,and AsO 3

3 - (arsenite ion)—in solutions. The prevalentforms vary according to the pH and redox potential of theenvironment (Rodrigues 2008 ). As release into surfacewater and groundwater occurs in steps and may suffervarious inuences of the medium conditions and presenceof other ions and compounds. Thus, it has been veried thatAs transportation among different environmental com-partments and its assimilation with other living organismsdepend on its oxidation state, environmental redox condi-tions, and biological activities (Mandal and Suzuki 2002 ;Welch et al. 2000 ).

As concentrations in air are usually low, although thereis an increase in more populated and industrialized areas.Beavington et al. ( 2004 ) showed metal concentrations in airparticulate from Port Kembla, Australia, from 1978 to2002. As varied in the range of 13.5–29.0 ng kg - 1 of particulate matter. Benin et al. ( 1999 ) determined As andother elements in dust from different Mexican cities, andmedian As values were 32, 42, and 113 ng kg - 1 in Chi-huahua, Monterrey, and Torreo ´ n, respectively. The inves-tigators observed that dust As levels decreased withdistance from the industrial sites. As usually enters theatmosphere through erosion caused by winds, volcanicemissions, volatilization from soils, ocean aerosols, andpollution. It is predominantly found in its inorganic formand is adsorbed on particulate matter usually at \ 2.5 l m.Dust is the main transport means of As emissions to theatmosphere. These particles are spread by the wind andreturn to the soil and watercourses because of wet and drydeposition (Mandal and Suzuki 2002 ; Carabantes and deFernicola 2003 ; Palmieri 2006 ; Csavina et al. 2012 ).

When assimilated by living organisms, As is biotrans-formed (Goering et al. 1999 ; Vahter 2002 ; Carabantes andde Fernicola 2003 ; Assis 2006 ; Palmieri 2006 ; Deschampsand Matschullat 2007 ; Lomax et al. 2012 ; Cullen 2014 ;Hunt et al. 2014 ). First, it suffers reduction reactions thatlater lead to methylation and make it less toxic as well asglutathione conjugation in the liver to form more polarmetabolites for excretion (detoxication process) (Goeringet al. 1999 ; Vahter 2002 ; Lomax et al. 2012 ; Cullen 2014 ;Hunt et al. 2014 ). At the cellular basis, it may interfere inmethyltransferase activity and oxidative phosphorylationand compete with phosphorus in metabolic reactions

(Goering et al. 1999 ; Vahter 2002 ; Lomax et al. 2012 ). It isa toxic bioaccumulative element to mammals (Goeringet al. 1999 ; Vahter 2002 ; Carabantes and de Fernicola2003 ; Assis 2006 ; Palmieri 2006 ; Deschamps andMatschullat 2007 ; Lomax et al. 2012 ; Cullen 2014 ; Huntet al. 2014 ). Historically, the methylation of inorganic Aswas believed to detoxify the metalloid because methylated

metabolites, such as monomethylarsinous acid (MMAsIII)and dimethylarsinous acid (DMAsIII), were found in theurine of exposed animals (Cullen 2014 ; Hunt et al. 2014 ).For the past decade, however, studies have shown thatmethylated arsenites, including MMAsIII and DMAsIII,are more toxic than As (Hunt et al. 2014 ).

Several studies have shown that As exposure by way of drinking water is the main form of human exposure(Mandal and Suzuki 2002 ; Carabantes and de Fernicola2003 ; WHO 2010 ; Bundschuh et al. 2012 ). Cases of chronic exposition to high levels of As in water have beenreported from many countries. Contaminations that oc-curred in Bangladesh (Nickson et al. 1998 , 2000 ; Anawaret al. 2011 ), India (Nickson et al. 2000 ; Chakraborty andSaha 1987 ), Taiwan (Tseng et al. 1968 ; Chen et al. 1994 ;Liao et al. 2011 ), Vietnam (Nguyen and Itoi 2009 ; Nguyenet al. 2009 ; Phuong et al. 2012 ), Mexico (Cebrian et al.1983 ), Chile (Carabantes and de Fernicola 2003 ; Bund-schuh et al. 2012 ) and Argentina (Smith et al. 1992 ;Hopenhayn-Rich et al. 1996 , 1998 ; Farı́as et al. 2003 ;Bundschuh et al. 2012 ) are among the most serious cases.

In Brazil, one of the most problematic areas is the IronQuadrangle in the state of Minas Gerais (MG; Matschullatet al. 2000 ; Deschamps et al. 2002 ; Borba et al. 2003 , 2004 ;Mello et al. 2006 , 2007 ; Deschamps and Matschullat 2007 ;Bundschuh et al. 2012 ) where the increase of As concen-trations in water and sediments is related to the elementreleased by mining activities. In addition to this region,other areas—such as the Ribeira Valley (Parana ´ and Sã oPaulo) (Companhia de Pesquisa de Recursos Minerais[CPRM] 2003 ; Figueiredo et al. 2007 ; Rodrigues 2008 ),Santana (Amapa´) (CPRM 2003 ) and Paracatu (MG)(CPRM 2003 ; Mello et al. 2006 ; Figueiredo et al. 2007 ;Mello et al. 2007 ; Andrade 2007 ; Andrade et al. 2008 ,2012 ; Rezende 2009 )—have shown high As concentrationsin water and/or sediments,

Paracatu River Basin is located predominantly in thenorthwest of MG [19 cities (92 %)] including also threecities in the state of Goia ´s and a small area of the FederalDistrict. It amounts to approximately 10 % of the total areaof the Sã o Francisco River Basin and is responsible fordraining a basin of about 45,000 km 2 accounting nearly24 % of the total ow of the São Francisco River (InstitutoMineiro de Gesta ˜o das Á guas 2010 ) The Paracatu RiverBasin was rst occupied by bandeirantes (scouts) and ad-venturers during the colonial period after the discovery of

Arch Environ Contam Toxicol

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Au in the region in the eighteenth century, which accel-erated the settlement of this region. This area is known asMorro do Ouro (Gold Mountain) and is located in Paracatu.After the decrease of Au production, the population beganto dedicate themselves to farming activities. Although theexploration of Au in Paracatu began in the eighteenthcentury, in the mid 1980s there was a boom of mining

activities with an indiscriminate use of mercury and con-sequential degradation of the area. (Tannu ´s et al. 2001 ;Gurgel 2007 ; Almeida 2009 ; Mulholland 2009 ) The mostimportant points of mining exploration were located alongCórrego Rico (Santos 2012 ). Au extraction still exists inthis region and is executed by a mining company, butprospectors are prohibited (Santos 2012 ). It is also relevantto note that there is a natural occurrence of arsenopyrite inthis region (Mello et al. 2006 ; Monteiro et al. 2006 ; An-drade et al. 2008 ).

Considering the naturally increased levels of As and thehistory of Au mining in the region, it is important to assessthe availability of As in the environment. The goal of thiswork was to evaluate the As distribution, mobility andtransport in Paracatu, MG, Brazil.

Materials and Methods

Samples

Water and Sediments

Two samplings (October 2010 and November 2011) wereperformed in Paracatu, MG, Brazil. The most importantpoints of Au-mining exploitation were located in Co ´ rregoRico (Santos 2012 ), which has its source close to the areaof mining in the Morro do Ouro. After draining the city, thestream travels a distance of approximately 60 km and owsinto the left bank of the Rio Paracatu (Tannus et al. 2001 ;Gurgel 2007 ). Five sampling points of surface water andsediment were chosen in the Co ´ rrego Rico to take accountof samples near the mining area, in the urban area, andafter draining the city (downstream). One point in atributary of the Co´ rrego Rico and three points in streamsoutside of the mining inuence, with one of them being inthe source area that supplies the city, were also chosen. Thegroundwater samples were also collected to cover areasnear the mining activity, the central urban area and ruralareas. Table 1 lists the geographical coordinates of thecollection points. Figure 1shows a map of the area.

In each sampling, the surface water and margin sedi-ments samples were collected at nine points in differentrivers and streams. At every point, surface water andsediment samples were collected next to the margin and inthe supercial layer (30-cm deep) using a bucket and

plastic shovel, respectively. Surface water samples werecollected before sediment samples.

Surface water (Asup) and sediment (Sed) samples werecollected and preserved according to United States Envi-ronmental Protection Agency (USEPA) recommendations(USEPA 2001 , 2007a ). Immediately after sampling, allwater samples were ltered through a 0.45- l m nitrocellu-lose membrane and were divided in two subsamples: onewas reserved for the speciation analysis (nothing was addedto this subsample), and the other one was acidied withconcentrated HNO 3 . They were stored in high-densitypolyethylene bottles and maintained frozen until analysis.The sediment samples were stored in plastic asks andwere refrigerated until further use. In the laboratory, thesesamples were dried at room temperature, manually disag-gregated in a morta, and sifted in two fractions (2–0.063and \ 0.063 mm). The nest fraction was used in the ana-lysis because is the most important fraction to show theprocesses occurring in this matrix.

Twelve groundwater samples (Asub) were collected(ve in the rst collection and seven in the second col-lection) in both urban and rural areas of Paracatu, whichtotaled ten different points. We were unable to collect atexactly the same place at all points during the rst andsecond collection. Sometimes we collected samples nearpoints as can be seen on the map shown (Fig. 1). Preser-vation recommendations were performed according toUSEPA guidelines (USEPA 2007b ).

Table 1 Geographical coordinates of the sampling points

Sampling point code Latitudes Longitudes

Asub 01 S 17 o 14 0160 00 W 46 o 52 0548 00

Asub 02 S 17o13 0062 00 W 46

o53 0306 00

Asub 03 S 17 o 12 008 00 W 46 o 51 055 00

Asub 04 S 17 o 12 0410 00 W 46 o 54 0029 00

Asub 05 S 17 o 14 0160 00 W 46 o 52 0548 00

Asub 06 S 17 o 13 0062 00 W 46 o 53 0306 00

Asub 07 S 17o12 008 00 W 46

o51 055 00

Asub 08 S 17o12 0410 00 W 46

o54 0029 00

Abica 01 S 17o11 0503 00 W 46

o55 0355 00

Abica 02 S 17o11 0503 00 W 46

o55 0355 00

Asup 01/Sed 01 S 17o12 0698 00 W 46

o53 0462 00

Asup 02/Sed 02 S 17o14 0413 00 W 46

o51 0697 00

Asup 03/Sed 03 S 17 o 13 0868 00 W 46 o 52 0471 00

Asup 04/Sed 04 S 17 o 13 0057 00 W 46 o 53 0427 00

Asup 05/Sed 05 S 17o12 0081 00 W 46

o51 0551 00

Asup 06/Sed 06 S 17 o 08 0856 00 W 46 o 49 0443 00

Asup 07/Sed 07 S 17 o 15 0360 00 W 46 o 57 0662 00

Asup 08/Sed 08 S 17o12 0249 00 W 46

o52 0500 00

Asup 09/Sed 09 S 17 8 18 015 00 W 46 8 46 015 00


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Vegetables

Vegetable samples were directly purchased from smallfarmers ( n = 17) or markets ( n = 10): lettuce ( n = 7),endive ( n = 3), spring onion ( n = 2), kale ( n = 9), mus-tard ( n = 1), and parsley ( n = 5). Then, they were storedin sealed plastic bags, frozen during transportation, andtriturated and lyophilized in the laboratory.

Standard Solutions and Reagents

All chemicals were of analytical grade. All solutions anddilutions were prepared using deionized water from a Milli-Q system (18.2 M X cm - 1 ; Millipore Direct-Q 3, Mol-sheim, France). Stock solutions (100 mg L - 1 ) of As(III) andAs(V) were prepared from As 2 O3 (Merck, Darmstadt, Ger-many) and Na 2 HAsO 4 .7H 2 O (Quimibra´s, Rio de Janeiro,Brazil), respectively. A mass of 0.1321 g of As 2 O3 (Merck,Darmstadt, Germany) was accurately weighted, dissolved in40.0 mL of a NaOH (Vetec, Rio de Janeiro, Brazil) 20 %(w/v) solution, neutralized with 80.0 mL of a 10 % (v/v)

HCl (Merck) solution, and diluted to 1,000 mL. To preparethe As(V) solution, 0.2082 g of Na 2 HAsO 4 7H 2 O was dis-solved in 500 mL of deionized water. For total As, a certi-ed standard solution (1,000 mg L - 1 ) was obtained fromMerck (Darmstadt, Germany). Working solutions were dailyprepared by dilution of the stock solutions.

In the sediment sample digestion, HCl, HNO 3 , HF, H 2 O2 ,and H 3 BO 3 (Merck, Darmstadt, Germany) were employed.In the hydride-generation process, NaBH 4 (Isofar, Duque deCaxias, Brazil), NaOH (Vetec, Rio de Janeiro, Brazil), andthiourea (Merck, Rio de Janeiro, Brazil) were also used.

Instrumentation

As determination in water and vegetables was performedusing a Perkin-Elmer AAnalyst FIAS 100 hydride gen-erator system coupled to a Perkin-Elmer AAnalyst 200ame atomic absorption spectrometer (FAAS) (Perkin-Elmer, Shelton, USA). An MHS-20 mantle heating systemwas used to heat the quartz cell, and a deuterium lamp wasused as the background corrector. An electrodeless

Fig. 1 Paracatu city map. a Location of Paracatu. b Paracatu sampling points of surface water and sediments. c Paracatu sampling points of groundwater


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discharge lamp of As that operated at 400 mA was used asthe energy source, and the As signal was detected at193.7 nm. The instrumental conditions were optimized asin previous work (Rezende et al. 2013 ) to perform total Asand trivalent As determination in water.

Total As determination in sediment samples was per-formed using the previously described FAAS, the samelamp, and air-acetylene ame (99.5 %, White Martins,Brazil) 10:3.3. The software WinLab 32 was used to obtainand process data.

A digital pH meter (Marte MB-10, Sa õ Paulo, Brazil), aPerkin-Elmer PE 2400Series II CHNS/OElemental Analyzer(Perkin-Elmer, Shelton, USA), a Hanna Instruments HI 9146portable dissolved oxygen (DO) meter (Hanna Instruments,São Paulo, Brazil), and a Hanna Instruments HI 8424 Nportable pH, redox potential, and temperature meter (HannaInstruments, Saõ Paulo, Brazil) were used for the physico-chemical characterization. An analytical balance (AX200;Shimadzu, Saõ Paulo, Brazil), a Fanen Excelsa II 206 BLcentrifuge (Saõ Paulo, Brazil), a TECNAL TE 394/1 oven fordrying with renewal and air circulation (São Paulo, Brazil), aMilestone Ethos 1 microwave oven for closed-vessel aciddigestion (Milestone, Sorisole, Italy), a Thermo ScienticModulyod-230 freeze dryer, two sievers Bertel (ThermoScientic, Caieiras, Brazil), and a Bronzinox sieve (Bronzi-nox, Santo Amaro, Brazil) were also used.

Analytical Procedure

Physicochemical Characterization of the Samples

The redox potential, pH, temperature, and DO were de-termined using portable devices to characterize the physi-cochemical properties of the water samples in the eld. Forthe physicochemical characterization of the sedimentsamples, the procedures included a grain size analysis andpH determination according to Soil Survey LaboratoryStaff (1992) cited by EMBRAPA guidelines ( 1997 ). Ca-tionic exchange capacity (CEC) estimates were calculatedaccording to the proposed method of Keng and Uehara(1974 ). Organic matter content was estimated from a CHNelemental analysis, which was executed in duplicate ac-cording to Machado et al. ( 2003 ) and Segnini et al. ( 2008 ).

Sediment-Sample Digestion

Sediment samples were digested using a cavity-microwaveoven and acid attack as described in Vieira et al. ( 2005 ).Approximately 200 mg of the sample ( \ 0.063 mm) wasdirectly weighted in the peruoroalkoxy (PFA) vessels, towhich 6.00 mL of aqua regia and 2.00 mL of concentratedHF were added. This mixture was left for approximately30 min; then, 2.00 mL of hydrogen peroxide was added to

each vessel. The vessels were closed and submitted to thedigestion program for 38 min. After the digestion programnished, the vessels were cooled to room temperature; thenthey were opened, and the mixture was transferred topolyethylene asks that had been previously decon-taminated. In each ask, 1.0 g of boric acid was added, andthe volume was adjusted to 30.0 mL. The procedure wasexecuted in triplicate for all samples. To evaluate the ac-curacy of the digestion procedure, the certied materialsNIST 2711 Montana Soil and GBW 8301 River Sedimentwere digested under the same conditions. All asks andglassware were maintained in an acid bath (10 % v/vHNO 3 ) for at least 24 h and subsequently washed threetimes with deionized water before their use.

Vegetable-Sample Digestion

The vegetables samples were also digested with acid attack using a cavity-microwave oven. Approximately 250 mg of a triturated and lyophilized sample was directly weightedin the PFA vessels, to which 3.00 mL of deionized waterand 3.00 mL of concentrated HNO 3 were added. Thismixture was left for approximately 30 min, and 2 mL of H2 O2 30 % m/m was later added to each vessel. The ves-sels were closed and submitted to the digestion program for20 min. After the digestion program completed, the bottleswere cooled to room temperature; then they were opened;the solution was transferred to polyethylene asks that hadbeen previously decontaminated; and their volumes wereadjusted to 25.0 mL. The procedure was executed in trip-licate for all samples. To evaluate the accuracy of the di-gestion procedure, the certied materials GBW 10016 TeaLeaves and NIST 1515 Apple were used.

Determination of As in Water Samples

For total As determination, a prereduction step usingthiourea was employed to determine As(V) as As(III). Analiquot of thiourea prepared in 0.01 mol L - 1 HCl was addedto the samples at a nal concentration of 0.10 % w/v. Thissolution was kept in contact at least for 1 h before the ana-lysis. The following instrumental conditions were applied:0.2/0.05 % w/v NaBH 4 /NaOH (4–6 mL min -

1 ) as the re-ducing agent, 10 % v/v HCl (8–12 mL min - 1 ) as the carrieracid, and argon (50 mL min - 1 ) as the carrier gas.

Based on the kinetic mechanisms of formation of arsinefrom As(III) and As(V) ions, the measurements of theAs(III) concentration in water samples were performed byselective hydride generation. The As(III) species was de-termined without prereduction step. All samples were di-luted by adding citrate buffer (pH 5) to a nal dilution of 50 % v/v. The operational conditions were as follows: re-ducing agent 0.2/0.05 % w/v NaBH 4 /NaOH w/vw/v


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(4–6 mL min - 1 ), carrier acid 0.1 mol L - 1 C6 H8 O7 (citricacid) (8–12 mL min - 1 ), and carrier gas Ar (50 mL min - 1 ).

The samples were divided into two parts: one part wasdiluted with citrate buffer (pH 5.0) for the determination of trivalent species; and to the another part, a thiourea solu-tion was added for the determination of total As determi-nation. The As(V) concentration was estimated as thedifference between total inorganic As and As(III).

Statistical Analysis

Statistical analysis of the data was performed using Mi-crosoft Excel 2007 for Windows and Statistica 8.0.

Results and Discussion

Average concentrations of total As in surface water,groundwater, and sediment from Paracatu, MG, Brazil, arelisted in Tables 2 and 3, respectively. To better charac-terize the environmental conditions that may inuence Asrelease and transport among these compartments, otherphysical and chemical parameters were also determinedand are listed in the same tables.

According to the Director Plan for Water Resourcesfrom the Paracatu River Basin (CBHParacatu 2005 ) andthe Brazilian legislation (CONAMA Resolution 357/ 2005 ),the rivers and streams studied in this work are classied aswatercourse class 2, which indicates that these waters canbe used for human supply (after conventional treatment),primary-contact recreation, protection of aquatic commu-nities, irrigation, aquaculture, and shing activities.

Surface-water samples had an average temperature of 26 C, pH levels close to neutrality, low values of redoxpotential, and DO \ 6.5 mg L - 1 . Four samples from therst collection had DO values \ 5 mg L - 1 , which is thequality level for this watercourse class. Furthermore, thisparameter concentration increased in the second collectionin all sampling points.

Six surface-water samples (Asup 01, Asup 02, Asup 03,Asup 06, Asup 08, and Asup 09) exceeded the tolerablelimits of As established to watercourse classes 1 and 2(10 l g L - 1 ). It is important to mention that the interna-tional limit of As in drinking water is 10 l g L - 1 accordingto WHO ( 2010 ). In the rst collection (October 2010), thesamples had 18–49 % of the total As in arsenite form. Inthe second collection (November 2011), the trivalent spe-cies increased in percentage at most sampling points with avariation of 7–73 % of the total As concentration in water.

Four surface-water samples (Asup 02, Asup 03, Asup07, and Asup 08) had Al concentrations greater than thelimit for watercourse class 2 (100 l g L - 1 ). Surface-watersamples Asup 01 and Asup 08 had manganese (Mn)

concentration levels greater then the limits established forclass 2 (100 l g L - 1 ). The Fe concentration in most sur-face-water samples also exceeded the limit value(300 l g L - 1 ) established for class 2.

Groundwater samples generally had a lower pH, redoxpotential, temperature, and DO than the surface-watersamples. Sample Asub 03 exceeded the limits of Fe forhuman consumption and recreation (300 l g L - 1 ) and wasonly appropriate for irrigation (500 l g L - 1 ), according toCONAMA Resolution 396/ 2008 . Sample Asub 02 ex-ceeded the tolerable limits of As (10 l g L - 1 ), aluminum(Al; 100 l g L - 1 ), Mn (100 l g L - 1 ), and Fe for humanconsumption, according to CONAMA Resolution 396/ 2008 . Both As and Al levels satised the limits for animalwatering. Al also approached the limit for irrigation, andAs levels were appropriate for recreation according to thevalues established by the legislation. Manganese levelsexceeded the limits for all uses. Therefore, the water isunsuitable for human consumption, animal watering, irri-gation, and recreation.

In general, the surface water samples from the secondcollection presented greater concentrations of Fe and Mnand lower concentrations of As than those from the rstcollection. Total As ranged from 0.55 to 110 l g L - 1 in therst sampling and from 0.50 to 31.4 mg l g L - 1 in thesecond one. In the time between the two collections, therewas a revitalization of the Co ´ rrego Rico removing wastefrom the banks and building retaining walls to decreaseerosion and recovery in margins. Moreover, the resultsshowed an increase of DO in the second collection, whichfavored a decrease of total As concentration because theoxidant medium favors the presence of the As(V), which isless mobile and coprecipitates with Fe oxides in pH nearneutrality.

The sediment samples were characterized by greaterpercentages of the sandy fraction and lower percentages of organic matter ( \ 5.5 %). Their pH values in water wereclose to neutral, and they were slightly alkaline with a fewexceptions. They had low DpH values, although mostsamples had increased this parameter in the module in thesecond collection. Considerable pH variations were notdetected in either sampling. In general, the samples hadgreater DpH values and greater organic matter content inthe second collection, whereas the ne sieve fraction per-centage ( \ 0.063 mm) was greater in the rst one.

All of the analyzed sediment samples presented Asconcentrations greater than the threshold effect level(TEL), probable effect level (PEL), and severe effect level(SEL) limits of the Canadian Council of Minister of theEnvironment (Canadian Council of Ministers of the Envi-ronment [CCME] 1999 : They were, respectively, 5.9, 17,and 33 mg kg - 1 . As previously mentioned, this regionpresents naturally high levels of arsenopyrite (Mello et al.


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T a

b l e 2

P h y s i c o c h e m i c a l p a r a m e t e r s o f w a t e r s a m p l e s f r o m P a r a c a t u

, M G , B

r a z i l , a n d c e r t i e d r e f e r e n c e m a t e r i a l N I S T 1 6 4 3 e t r a c e e l e m e n t s i n w a t e r

p H

T e m p e r a t u r e

( C )

R e d o x

p o t e n t i a l ( m V )

D i s s o l v e d

o x y g e n

( m g L -

1 )

A l ( l g L -

1 )

F e ( l g L -

1 )

M n ( l g L -

1 )

T o t a l A s ( l g L -

1 )

A r s e n i t e ( l g L -

1 ) a

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g

F i r s t S e c o n d


F i r s t

S e c o n d

F i r s t S e c o n d F i r s t

S e c o n d

F i r s t

S e c o n d

F i r s t

S e c o n d

F i r s t

S e c o n d

F i r s t

S e c o n d

A s u b

0 1

5 . 7 1

5 . 4 5

2 4 . 8

2 5 . 4

6 8 . 5

8 4 . 9

3 . 0 0

4 . 1 7

1 2 8

±

9

\ 1 0 0

\ 3 0 0

2 0 4 ±

1 3

6 8 ±

3

1 2 ±

3 3

0 . 3 8 ±

0 . 0 2

1 . 9 ±

0 . 1

\ 1 . 3

\ 1 . 3

A s u b

0 2

6 . 3 0

–

3 0 . 0

–

3 6 . 2

–

3 . 4 7

–

3 8 0

±

3 0

–

3 7 0 0 ±

1 0 0

–

1 6 4 8 ±

7 2

–

1 5 . 7

±

1 . 2

–

9 . 9 ±

0 . 5

–

A s u b

0 3

7 . 6 1

–

2 9 . 2

–

– 3 9 . 2

–

4 . 1 7

–

4 3 ±

2

–

5 9 0 ±

3 0

–

4 . 4 ±

0 . 2

–

1 . 6 2 ±

0 . 0 3

–

\ 1 . 3

–

A s u b

0 4

7 . 2 1

–

2 9 . 0

–

– 1 5 . 8

–

4 . 6 2

–

8 0 ±

2

–

\ 3 0 0

–

9 . 0 ±

0 . 2

–

1 . 1 1 ±

0 . 0 4

–

\ 1 . 3

–

A s u b

0 5

–

5 . 6 9

–

2 2 . 9

–

7 0 . 5

–

3 . 3 1

–

\ 1 0 0

–

8 0 8 ±

3 6

–

1 3 4 ±

3 3

–

1 0 . 0

± 0 . 3

–

–

A s u b

0 6

–

6 . 7 3

–

2 3 . 8

–

1 1 . 3

–

–

1 0 5 ±

1 7

–

9 3 ±

7

–

4 3 ±

3 3

–

0 . 3 5 ± 0 . 0 3

–

\ 1 . 3

A s u b

0 7

–

7 . 1 7

–

2 7 . 5

–

– 1 4 . 1

–

–

\ 1 0 0

–

\ 3 0

–

3 8 ±

3 3

–

2 . 1 ±

0 . 3

–

\ 1 . 3

A s u b

0 8

–

7 . 2 7

–

2 6 . 6

–

– 1 8 . 8

–

5 . 3 5

–

\ 1 0 0

–

\ 3 0

–

\ 3

–

3 . 3 ±

0 . 4

–

\ 1 . 3

A b i c a

0 1

6 . 8 7

5 . 6 4

2 4 . 6

2 4 . 8

3 2 . 0

7 3 . 3

5 . 3 2

5 . 5 8

4 9 ±

1

\ 1 0 0

\ 3 0 0

\ 3 0

2 . 2 ±

0 . 1

\ 3

0 . 2 7 ±

0 . 0 3

1 . 4 ±

0 . 2

\ 1 . 3

\ 1 . 3

A b i c a

0 2

–

7 . 2 4

–

2 7 . 2

–

– 1 7 . 8

–

–

\ 1 0 0

–

\ 3 0

–

\ 3

–

3 . 6 ±

0 . 5

–

\ 1 . 3

A s u p

0 1

7 . 4 4

6 . 9 5

2 5 . 2

2 3 . 6

2 . 0

– 1 . 2

5 . 4 3

5 . 7 2

4 8 ±

2

\ 1 0 0

7 0 0 ±

1 0 0

3 5 3 ±

1 3

1 1 5 ±

1

6 5 ±

3 3

1 8 . 7

±

0 . 5

8 . 8 ±

0 . 2

8 . 5 ±

0 . 4

5 . 0 ±

0 . 1

A s u p

0 2

7 . 3 3

7 . 4 3

2 5 . 7

2 4 . 4

– 2 2 . 8

– 2 8 . 8

4 . 1 4

5 . 1 7

1 0 7

±

1

\ 1 0 0

1 0 0 0 ±

1 0 0

3 0 6 ±

1 3

9 0 ±

4

3 1 ±

3 3

5 4 . 8

±

0 . 2

2 8 . 0

± 0 . 2

2 1 . 8

±

1 . 0

1 7 . 1

±

0 . 5

A s u p

0 3

6 . 7 4

7 . 0 8

2 5 . 9

2 8 . 5

1 0 . 8

– 8 . 0

1 . 5 4

5 . 8 9

1 0 9

±

2

\ 1 0 0

2 0 0 0 ±

1 0 0

2 3 0 ±

1 3

7 8 ±

3

1 0 ±

3 3

4 0 . 0

±

0 . 1

1 9 . 9

± 0 . 3

1 3 . 4

±

0 . 7

1 4 . 5

±

0 . 5

A s u p

0 4

6 . 8 2

6 . 6 9

2 5 . 4

2 8 . 5

7 . 8

1 9 . 6

5 . 5 8

6 . 0 5

4 3 ±

5

\ 1 0 0

1 9 0 0 ±

1 0 0

3 8 6 ±

1 3

4 7 ±

1

2 0 ±

3 3

3 . 1 9 ±

0 . 0 3

6 . 3 ±

0 . 1

\ 1 . 3

3 . 6 ±

0 . 1

A s u p

0 5

7 . 8 3

7 . 5 1

2 6 . 4

2 5 . 7

– 5 1 . 7

– 3 6 . 2

5 . 0 4

6 . 5 2

3 2 ±

1

\ 1 0 0

\ 3 0 0

5 3 ±

7

1 4 . 5

±

0 . 1

1 9 ±

3 3

9 . 2 1 ±

0 . 1 3

1 5 . 2

± 0 . 4

3 . 8 ±

1 . 1

7 . 4 ±

0 . 1

A s u p

0 6

7 . 9 6

7 . 8 2

2 7 . 0

2 6 . 4

– 5 9 . 8

– 5 0 . 2

4 . 8 9

5 . 8 3

5 4 ±

1

\ 1 0 0

\ 3 0 0

1 0 0 ±

7

9 . 0 ±

0 . 1

2 2 ±

3 3

2 8 . 6

±

0 . 9

2 6 . 9

± 0 . 1

1 3 . 5

±

0 . 6

1 3 . 7

±

0 . 4

A s u p

0 7

6 . 8 9

6 . 9

2 4 . 5

2 4 . 8

2 . 6

1 . 9

4 . 1 3

6 . 0 1

1 8 7

±

8

\ 1 0 0

7 0 0 ±

1 0 0

1 0 9 0 ±

3 6

2 2 . 9

±

0 . 6

4 1 ±

3 3

0 . 5 5 ±

0 . 0 1

0 . 5 0 ± 0 . 0 2

\ 1 . 3

\ 1 . 3

A s u p

0 8

7 . 5 7

7 . 8 9

3 0 . 7

2 4 . 0

– 3 7 . 1

4 7 . 2

3 . 2 8

6 . 0 3

9 1 2

±

9 2

\ 1 0 0

2 2 0 0 ±

1 0 0

4 0 6 ±

1 3

3 0 0 ±

2 5

1 9 ±

3 3

1 1 0 . 0 ±

0 . 3

3 1 . 4

± 0 . 2

5 3 . 7

±

2 . 2

4 . 3 ±

0 . 7

A s u p

0 9

7 . 6 4

7 . 0 3

2 3 . 9

2 6 . 9

– 3 8 . 3

– 5 . 9

4 . 5 4

5 . 9 0

9 6 ±

1 3

\ 1 0 0

4 0 0 ±

1 0 0

5 7 ±

7

1 9 ±

1

\ 3

7 3 . 7

±

3 . 2

6 . 4 ±

0 . 2

1 3 . 6

±

0 . 5

0 . 4 7 ±

0 . 0 2

C R M 1 6 4 3 e

C e r t i e d

1 4 1 . 8

±

8 . 6

9 8 . 1

±

1 . 4

3 8 . 9

7 ±

0 . 4 5

6 0 . 4

5 ±

0 . 7 2

–

O b t a i n e d

1 3 9 . 7

±

2 9 . 3

9 6 . 2

±

2 . 1

3 6 . 8

4 ±

5 . 8 9

6 3 . 8

0 ±

3 . 7 0

–

a

D a t a f r o m R e z e n d e e t a l . (

2 0 1 3 )


1 3


8/15

2006 ; Monteiro et al. 2006 ; Andrade et al. 2008 , 2012 ;Costa Jr 1997 ). As concentrations in the samples variedfrom 125 to 466 times the TEL limit.

Because the sediments are formed with different miner-alogical substrates and organic matter deposition at thebottom of watercourses, the As content in this compartmentwas expected to be greater than in other areas becausearsenopyrite is a common mineral in this region. Conse-quently, the most important issue is the risk of As release tothe watercourse, which depends on several previouslymentioned factors such as pH, redox potential, substrategrain size, type of clay mineral, and physical parameters of the hydrous bodies including water ow and temperature.

In a previous study (Rezende et al. 2013 ), a method toquantify arsenite in water was developed and applied tosome samples from Paracatu. The information related toAs speciation is important because of the difference in thetoxicity and in the mobility variation in the environment.The total As and arsenite in water and total As in thesediment data were compared, and Fig. 2 shows that thereis a relation between the As concentration in the sedimentand that in the surface water, i.e., the As concentration inwater was greater at the points with greater As levels in thesediment. It is worth emphasizing that the total As con-centration in water ranged from 0.35 to 110 l g L - 1 , i.e., upto 11 times the legal limits, whereas in the sediments thetotal As concentration varied from 738 to 2750 mg kg - 1 ,i.e., 125–466 times greater then the legal limits. It is im-portant to note that the As concentration at point Asup 07,which corresponds to the water body from which the waterfor public supply of Paracatu is obtained, is considerablylow, which satises the legislation requirements regardingwater for human consumption. Looking at Figs. 1 and 2together, it is possible note that the As concentration of thesediment decreases with increasing distance from themining area. Sampling points P1 and P8 are located closeto the mine. Point P7 is located approximately 20 km awayfrom the urban area of the city (source used for the watercatchment for public supply of the Paracatu). Point P9 islocated on the Co´ rrego Rico outside of town. A signicantpositive correlation between As in surface water and insediment was veried. As in water can be provenient byparticulate matter that was deposited in the sediment or if the sediment releases the As into the water column. Inaddition, it is possible there is atmospheric deposition of dust, but this matrix was not analyzed. Furthermore, toverify As transport among environmental compartments inthe studied area, the total As level in the vegetables sold intown was measured. The results are listed in Table 4.

As concentrations in the analyzed vegetables are lowerthen the critical range of values according to Kabata-Pendias and Pendias (1992) cited by Palmieri ( 2006 ),above which the toxicity effects are likely, and to McNihol T

a b l e 3

P h y s i c o c h e m i c a l p a r a m e t e r s o f s e d i m e n t s a m p l e s f r o m P a r a c a t u

, M G

, B r a z i l , a n d c e r t i e d r e f e r e n c e m a t e r i a l s N I S T 2 7 1 1 M o n t a n a S o i l a n d G B W 8 3 0 1 R i v e r S e d i m e n t

S a m p l e p H

D p H

S e d i m e n t

f r a c t i o n ( % )

\ 0 . 0 6 3 m m

O M ( % )

A l ( % )

A s ( m

g k g -

1 )

F e ( % )

M n ( m g k g -

1 )

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g

S a m p l i n g


F i r s t

S e c o n d F i r s t

S e c o n d

F i r s t

S e c o n d

F i r s t

S e c o n d

F i r s t

S e c o n d

F i r s t

S e c o n d

F i r s t

S e c o n d

S e d 0 1

6 . 2 1

7 . 1 6

– 0 . 2

6

– 0 . 8

1

1 2 . 5

8 . 4

1 . 0 ±

0 . 1

1 . 8

± 0 . 1

4 . 7 ± 0 . 2

6 . 0 ± 0 . 4

2 4 8 0 ±

1 2 0

2 7 5 0 ±

1 6 0

7 . 1 ± 0 . 2

9 . 1 ± 0 . 2

6 7 1 ± 2 8

1 2 8 3 ±

3 9

S e d 0 2

7 . 1 1

6 . 9 8

– 0 . 6

3

– 0 . 8

0

5 . 6

1 . 1

5 . 1 ±

1 . 2

4 . 4

± 0 . 1

5 . 6 ± 0 . 2

3 . 5 ± 0 . 2

2 0 9 0 ±

2 5 0

1 4 1 0 ±

7 3

6 . 1 ± 0 . 2

9 . 1 ± 0 . 3

1 9 3 4 ± 9 6

6 8 0 ±

2 4

S e d 0 3

7 . 2 3

6 . 9 7

– 0 . 5

0

– 0 . 6

5

2 6 . 9

7 . 8

3 . 4 ±

0 . 1

4 . 4

± 0 . 3

6 . 5 ± 0 . 1

6 . 9 ± 0 . 1

1 8 7 0 ±

1 1 0

1 3 5 0 ±

1 2 0

6 . 0 ± 0 . 1

7 . 3 ± 0 . 2

2 1 5 ± 9

6 2 0 ±

4

S e d 0 4

7 . 5 3

8 . 3 1

– 0 . 6

3

– 0 . 2

1

2 5 . 4

4 . 2

1 . 2 ±

0 . 2

6 . 3

± 0 . 1

5 . 4 ± 0 . 3

3 . 4 ± 0 . 1

1 6 7 0 ±

1 9 0

9 5 2 ±

1 3 0

3 . 1 ± 0 . 1

9 . 4 ± 0 . 5

3 1 0 ± 1 2

1 3 6 4 ±

8 3

S e d 0 5

7 . 4 2

7 . 6 1

– 0 . 4

2

– 0 . 7

3

3 3 . 1

6 . 4

2 . 8 ±

0 . 1

1 . 8

6 ± 0 . 0 5

5 . 6 ± 0 . 7

4 . 1 ± 0 . 3

1 5 3 0 ±

1 8 0

8 1 8 ±

3 8

4 . 1 ± 0 . 1

3 . 7 ± 0 . 2

8 9 5 ± 3 1

1 0 6 2 ±

5 3

S e d 0 6

8 . 0 5

8 . 1 1

– 0 . 3

5

– 0 . 3

4

1 . 8

0 . 6

2 . 3 ±

0 . 1

2 . 4

± 0 . 2

3 . 9 ± 0 . 3

3 . 1 ± 0 . 1

1 9 4 0 ±

1 3 0

1 0 3 0 ±

6 5

4 . 4 ± 0 . 2

3 . 4 ± 0 . 2

1 0 8 4 ± 3 3

1 7 3 4 ±

1 2

S e d 0 7

5 . 1 6

6 . 9 5

– 0 . 7

4

– 0 . 4

7

3 8 . 0

1 9 . 3

5 . 4 4 ±

0 . 0 1 3

. 5 ± 0 . 8

5 . 1 ± 0 . 1

4 . 4 ± 0 . 2

9 4 1 ±

1 1 0

7 3 8 ±

1 5

3 . 7 ± 0 . 1

4 . 0 ± 0 . 2

3 6 1 ± 3 1

4 4 4 ±

1 2

S e d 0 8

8 . 0 8

7 . 0 0

0 . 0 4

– 0 . 4

7

4 6 . 7

1 1 . 3

2 . 8 ±

0 . 1

5 . 0

± 0 . 1

4 . 2 ± 0 . 1

3 . 3 ± 0 . 2

1 9 3 0 ±

1 1 0

9 4 6 ±

8 0

7 . 8 ± 0 . 1

5 . 8 ± 0 . 2

2 3 2 ± 2 0

1 0 5 6 ±

7 2

S e d 0 9

6 . 8 2

5 . 6 5

– 0 . 7

1

– 0 . 6

5

2 3 . 3

1 0 . 4

3 . 4 ±

0 . 1

2 . 0

± 0 . 2

5 . 6 3 ± 0 . 0 2

6 . 3 ± 0 . 5

1 4 3 0 ±

1 1 0

7 8 9 ±

7 5

4 . 7 ± 0 . 3

4 . 8 ± 0 . 1

3 5 4 ± 2 7

6 2 ±

3

N I S T 2 7 1 1

C e r t i e d

6 . 5 3 ± 0 . 0 9

1 0 5 ±

8

2 . 8 9 ± 0 . 0 6

6 3 8 ± 2 8

O b t a i n e d

5 . 6 1 ± 0 . 3 3

1 0 1 ±

3

2 . 8 5 ±

0 . 0 6

6 4 8 ± 2 3

G B W 8 3 0 1

C e r t i e d

–

5 6 ±

1 0

3 . 9 4 ±

0 . 1 3

9 7 5 ± 3 4

O b t a i n e d

2 . 8 7 ± 0 . 3

5 4 ±

3

3 . 7 1 ±

0 . 0 1

9 1 8 ± 3 8


1 3


9/15

and Beckett (1985) cited by Palmieri ( 2006 ), above whichAs may cause at least a 10 % weakening of the plant vi-tality (Table 4).

The obtained As concentrations in this work were alsolower than the rates found in other studies. Anawar et al.(2012 ) determined As and Pb in various vegetables sold insupermarkets in Spain and Bangladesh. The samples fromBangladesh had high concentrations of AS B 423 l g kg - 1

because of the As contamination problems in the area.Some vegetables from Bangladesh had B 3 times greaterconcentrations than the samples from Spain. Baig and Kazi(2012 ) determined As in various vegetables grown incontaminated areas in Pakistan and found amountsB 1,700 l g kg - 1 . As absorption from contaminated soilswas identied in both studies. Monitoring in food producedin this regions is important because of the risks of attainingthe maximum tolerable amount of ingestion, particularly inchildren.

As absorption by land plants from soil is usually low.One of the proposed mechanisms is that arsenate may beabsorbed by the plant against the phosphate anion becauseof their ion size. Other factors, such as irrigation and at-mospheric deposition, may contribute to increase absorp-tion. Although the concentrations are low, we can observethe relation among total As concentrations in water, sedi-ment, and vegetable samples (Fig. 3). To better determinethis correlation, only vegetables with known place of cul-tivation were used ( n = 17) (see Table 4 and Supplemen-tary Information Table S1).

Figure 3 shows that the second sampling had lower totalAs concentrations in water, sediment, and vegetable sam-ples than the rst sampling. The results show a relationbetween As amounts in the different environmental com-partments studied, which suggests that As was transportedamong them. However, mobility may be low if the Asamounts in the vegetables are considered normal.

To understand the factors that contribute to As transportand speciation, the obtained data for the total As andAs(III) in water, total As in the sediment, and other de-termined physicochemical parameters were submitted tostatistical treatment to search for the correlations. Pearsoncorrelation ( P \ 0.05) was used, and several signicantcorrelations were identied (Tables S1 and S2). A highcorrelation ( ? 0.89 and ? 0.77, respectively, for the rst andsecond collections) was observed between total As insediments and that in water.

In the second collection, the Al content and ne-particlepercentage in the sediment had a signicant and positivecorrelation ( ? 0.57). Al silicates are frequently the mainconstituents in clay minerals. Other works (Costa Jr 1997 ;Mello et al. 2006 ; Andrade et al. 2008 ; Rezende 2009 ) thatinvolved soil or sediment samples from this region iden-tied kaolinite, gibbsite, and muscovite as some of themain minerals in the samples. A negative correlation be-tween the As concentrations in the water—both total andtrivalent—and sediment and in the \ 0.063-mm particlepercentage was observed.

The pH values in water correlate positively with total As(? 0.79) and As(III) ( ? 0.64) in water and negatively with Al(- 0.49), Fe ( - 0.89), and Mn ( - 0.58) concentrations in wa-ter. Fe and Mn amounts in sediment also correlate positivelywith the total As concentration in water (w/Fe ? 0.71; w/Mn? 0.74), As(III) in water (w/Fe ? 0.88; w/Mn ? 0.65), and totalAs in sediment (w/Fe ? 0.88; w/Mn ? 0.62). It was also ob-served that trivalent As positively correlated with Mn in water(? 0.49), which suggests that As dissolution may be associ-ated with Mn oxide dissolution. The increase in pH valuesmay favor the dissolution of As bound in the sedimentthrough an electrostatic interaction (Welch et al. 2000 ;Mandal and Suzuki 2002 ; Rodrigues 2008 ; Figueiredo 2010 ).

Total and trivalent As concentrations in water in the rstcollection negatively correlated with the pH in sediment

Fig. 2 Correlation among totaland trivalent As in water andtotal As in sediment


1 3


10/15

(w/total As - 0.72; w/As(III) - 0.38) and DpH (w/total As- 0.54; w/As(III) - 0.56), whereas with As in the sediment,these correlations were positive. The second collection haslower total and trivalent As concentration in water than therst collection and positively correlated with pH values inthe sediment (w/total As ? 0.66; w/As(III) ? 0.57) and DpH(w/total As ? 0.67; w/As(III) ? 0.60). In the second col-lection, DO increased in water at all points; the sedimentshad greater pH values; the Fe and Mn contents in thesediment increased at most points; and the percentage of \ 0.063-mm particles was decreased. During total or partialdissolution of As secondary minerals, part of the soluble Asadsorbed by Al, Fe, and Mn oxides in the soil or sedimentmay be retained. Because of the increase of Fe and Mn inthe sediment, more As may be retained in the solid phase,which contributes to its reduction in water. Anawar et al.

(2011 ) also found a positive and signicant correlationamong As, Fe, and Mn concentrations in sediments. Theinvestigators suggested that the decrease of As in sedi-ments might occur because of the coprecipitation with Feand Mn ions, which may occlude the As in the oxide, orbecause of specic adsorption, which proves their stronginteraction and contributes to the As low mobility from thesediment. According to Nriagu ( 1994 ), arsenate is pre-dominant in alkaline and oxygenated media. In addition,this species has lower mobility and greater afnity with Feand Mn oxides, which may justify the decreased As con-centration in water in the second sampling. The total Asconcentration in water and, consequently, As(III) concen-tration were also lower in the second collection; however,the trivalent species presented greater percentages in thiscollection in relation to the total concentration possibly

Table 4 Total As concentrationin vegetables from Paracatu andcritical values in plants

A the level with probable toxiceffects (Kabata-Pendias andPendias 1984 cited by Palmieri2006 ); B probable values thatweaken plant vitality by 10 %(McNihol and Beckett; 1985cited by Palmieri 2006)a

Vegetables with a knownplace of cultivation

Vegetables samples(wet mass)

Place of cultivation As ( l g kg - 1 ) Critical concentration ( l g kg - 1 )

A B

Endive 01 a Next to Asub 01, P3 100 ± 5 500–2,000 100–2,000

Endive 02 Unknown \ LOD

Endive 03 a Next to P6 59 ± 1

Kale 01 a Next to Asub 07, P5 \ LOD 650–2,600 130–2,600

Kale 02 Unknown 81 ± 1

Kale 03 Unknown 125 ± 15

Kale 04 Unknown 12.0 ± 0.5

Kale 05a

Next to P6 8.0 ± 0.2

Kale 06 Unknown \ LOD

Kale 07 Unknown \ LOD

Kale 08a

Next to P3 \ LOD

Kale 09a

Next to P3 \ LOD

Lettuce 01 a Next to Asub 08, P5 \ LOD 300–1,200 60–1200

Lettuce 02 a Next to Asub01, P3 28 ± 2

Lettuce 03a

Next to P7 \ LOD

Lettuce 04a

Next to P6 10 ± 1Lettuce 05 Unknown 60 ± 1

Lettuce 06a

Next to ASub 04 22 ± 1

Lettuce 07 Unknown 44 ± 1

Mustard 01 a Next to ASub 04 73 ± 6 650–2,600 130–2,600

Parsley 01a

Next to P2 120 ± 4 1100–4,600 220–4,600

Parsley 02 Unknown 86 ± 4

Parsley 03a

Next to P3 80 ± 10

Parsley 04a

Next to P1 18 ± 4

Parsley 05a

Next to P1 18 ± 3

Spring onion 01 Unknown \ LOD 300–1,200 60–1,200

Spring onion 02 a Next to P1 26 ± 2

GBW 10016 Certied 90 ± 10Obtained 88 ± 7

CRM 1515 Certied 38 ± 7

Obtained 36 ± 7


1 3


11/15

because the trivalent species had greater mobility and moreweakly interacted with the solid particles.

A correlation between the arsenite concentration inwater and DO and the Fe concentration in sediments andredox potential was also observed, which shows that theseparameters are important to As speciation in the aquaticenvironment. Because As is found in an anionic form, itsbehavior is opposite to that of other trace elements; thus, itsmobility increases when pH increases as well as in re-ducing conditions (Assis 2010 ). Some sampling points hadnegative redox potential values, which indicate reducingconditions and alkaline pH, favoring its mobility. Fig-ure 4 shows that the sampling points with low redox

potentials also had high total As concentrations in water.The correlation with Fe suggests that the arsenite concen-tration in water may be associated with this species dis-solution coprecipitated with Fe oxides or superciallyadsorbed through electrostatic interaction because there isalso a signicant and positive correlation with DpH. Inaddition, a more oxidant medium corresponds to a lowertotal As concentration in water.

Some investigators have showed that in addition to thepH conditions, organic matter contents, and Al, Fe, and Mnoxi-hydroxides, microorganisms also play an importantrole in the As-dissolving process and As transport fromsediments to surface water and groundwater. Anawar et al.(2011 ) studied groundwater contamination in Bangladesh.The investigators determined that the As concentration insurface water, groundwater, and sediments was 0.4–5.0,47.5–216.8, and 0.27–13.26 mg kg - 1 , respectively. Lowredox potential and DO values, virtually neutral pH, andhigh Al, Fe, and Mn oxide amounts were also observed.The investigators suggested that As mobilization in thestudied area is correlated with reducing conditions. Liaoet al. (2011 ) studied As mobility in aquifers in Taiwan. Theinvestigators found an As concentration of B 562.7 l g L - 1

in water, approximately 7 mg kg - 1 in sediments, low or-ganic matter content, and high Fe oxide amounts. Phuonget al. ( 2012 ) evaluated the factors and sources of ground-water contamination in Vietnam and found As concentra-tion B 703 l g L - 1 in water and 7.37–25.1 mg kg - 1 in

Fig. 3 Box-plot graphics. a Total As in water samples. b Total As insediment samples. c Total As in vegetable samples

Fig. 4 a Correlation between total As in water and redox potential(Eh). b Correlation between Arsenite in water and redox potential (Eh)


1 3


12/15

sediments, which were characterized by high Fe and Mnamounts in sediments, low redox potential and DO values,and virtually neutral pH.

In these three works, notably similar physicochemicalconditions were observed, and the investigators concludedthat the high As mobility, which contaminated the hydricresources, occurred because microorganisms participatedin the process of reductive dissolution of Fe oxides andorganic matter decomposition, which are two importantmeans of xation of As in sediments. These works onlydiffer from the present study in Paracatu regarding the Asconcentration in water and sediment. In Paracatu, the Asconcentration is high in sediment and low in water com-pared with the values in these works. Despite the highconcentration of As in sediment at these points, the pres-ence of Fe oxi-hydroxides and aluminosilicates may ex-plain its retention in the sediments. The same behavior wasobserved in other areas in Brazil such as Nova Lima andSanta Bá rbara (Deschamps and Matschullat 2007 ; Melloet al. 2006 , 2007 ). Studies performed (Pereira et al. 2007 ;Andrade et al. 2008 ; Rezende 2009 ) with sediment samplesfrom Brazilian areas with high As, Fe, and Mn concen-trations, which were submitted to sequential extractionprocedures, show that even at high concentrations As re-mains virtually immobile.

When high Fe oxi-hydroxide amounts are available,even in oxic surfaces of water or soil, the diluted As con-centration is low, and they are also low when Fe suldesexist. (Figueiredo 2010 ; Sun et al. 2012 ) In both oxidationstates, arsenite and arsenate may be adsorbed by Al, Fe,and Mn oxi-hydroxides, which illustrates the important roleof these elements in As mobility control (Deschamps andMatschullat 2007 ; Mello et al. 2006 , 2007 ; Silva et al.2010 , 2012 ). However, As(III) is more mobile, toxic andsoluble than As(V). The greater mobility of As(III) may beexplained by the nature of the interaction of this specieswith the solid surface in the soil, which makes supercialcomplexation, whereas As(V) produces ligand exchange(Rodrigues 2008 ; Ladeira and Ciminelli 2000 , 2004 ). AtpH [ 5 and in environments that are rich in particlescontaining Fe, As remains virtually still (Rodrigues 2008 ;Nriagu 1994 ).

Mello et al. ( 2006 ) studied the As mobility in soils andsediments in contaminated areas in MG, Brazil. The in-vestigators veried that As mobility does not depend on thetotal As concentration, but it is correlated with the Fe andMn oxi-hydroxide, gibbsite amounts, and organic mattercontent. Even in the presence of microorganisms and underreducing conditions, As has low mobility because there iscontinuous solubilization and precipitation processes evenif in low proportions.

Our study is consistent with other works in the lit-erature suggesting that As in water is mostly solubilized

because of reducing conditions with low oxygenation andalkaline pH. Nevertheless, the nature of the interaction of Fe and Mn oxides with a high As concentration in thesediment is sufciently strong to retain most parts of As inthe solid phase, which considerably decreases its solubi-lity and the surface water and groundwater contaminationin Paracatu.

In addition, it is emphasized that although the As con-centration in water is greater than the legal limit at somepoints, it does not follow the same proportions of violationof established limits to sediments. The presence of high Al,Fe, and Mn concentrations in the sediment, the slightlybasic pH, and the low redox potential retain most of the Asin the sediment. In the second collection, the increased DOconcentration was important to the decrease of As con-centration in the water. Preservation and maintenance of riverbanks, revegetation, and sewage treatment before itsdischarge in rivers, which are some alternatives that mayfavor a DO concentration [ 5 mg L - 1 , decreases the totalAs concentration in water and favors oxidation in thearsenate form.

Conclusions

All of the analyzed sediment samples and 37 % of thewater samples from the rivers and streams of Paracatupresented As concentrations greater than the quality stan-dards established by CCME and USEPA. The vegetablesamples presented low As concentrations. Although the Asconcentration in vegetables is normal, we observed a re-lation with As concentrations in water and in sedimentfrom nearby areas, which indicates that these plants ab-sorbed As. Systematic studies, including a greater numberof vegetable samples and variables, are necessary to betterelucidate the transport of the metalloid to this matrix.

Despite the high amounts of As in sediments (125–466times greater than the TEL standard), the results show lowdisponibility to the watercourse and even to plants, mainlybecause Fe and Mn oxyhydroxides and Al minerals arepresent, which signicantly immobilizes As in the solidphase. However, it is advisable to frequently monitor theconcentration of these elements in the water and sedimentsof the region, as well as the pH, the redox potential, and theDO determination, so that if there is any variation in theenvironment conditions, corrective actions may beexecuted to stop or minimize the contamination caused bythe solubilization of the elements in the sediments.

Acknowledgments The authors thank the Coordenação de Aper-feiçoamento de Pessoal de Nı ´vel Superior, Conselho Nacional deDesenvolvimento Cientı ćo e Tecnolo´gico, Fundaça õ de Amparo a`Pesquisa do Estado de Minas Gerais, and Centro Federal de Educaça õTecnolo´gica de Minas Gerais for their nancial support. They are also


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grateful to the Metallic Trace Laboratories from CDTN and CETECfor the water analysis.

References

Agency for Toxic Substances and Disease Registry (2011) Priority listof hazardous substances. http://www.atsdr.cdc.gov/spl/resources/ ATSDR_2011_SPL_Detailed_Data_Table.pdf . Accessed 25 Feb 2014

Almeida BS (2009) Geoquı ´mica dos litos carbonosos do depo ´ sitoMorro do Ouro, Paracatu, Minas Gerais. Dissertation, Univer-sidade de Brası ´lia, Brasilia, Brazil

Anawar HM, Akai J, Mihaljevic M, Sikder AM, Ahmed G, Tareq SMet al (2011) Arsenic contamination in groundwater of Bangla-desh: perspectives on geochemical, microbial and anthropogenicissues. Water 3:1050–1076

Anawar HM, Garcia-Sanchez A, Hossain MN, Akter S (2012)Evaluation of health risk and arsenic levels in vegetables sold inmarkets of Dhaka (Bangladesh) and Salamanca (Spain) byhydride generation atomic absorption spectroscopy. Bull Envi-ron Contam Toxicol 89:620–625

Andrade RP (2007) Controle da mobilidade geoquı ´mica do arseˆnioem ambiente de drenagem a ćida de mina. Dissertation, Univer-sidade Estadual de Campinas, Campinas, Brazil

Andrade RP, Figueiredo BR, Mello JWV, Santos JCZ, Zandonadi LU(2008) Control of geochemical mobility of arsenic by liming inmaterials subjected to acid mine drainage. J Soil Sediment8:123–129

Andrade RP, Mello JWV, Windmo ¨ller CC, Silva JBB, Figueiredo BR(2012) Evaluation of arsenic availability in suldic materials fromgold mining areas in Brazil. Water Air Soil Pollut 223:4679–4686

Assis RA (2006) Aperfeiçoamento e Aplicações de uma metodologiapara aná lise de especiaça õ de arsê nio por eletroforese capilarcom detector de ICPMS. Thesis, Pontifı ćia UniversidadeCató lica do Rio de Janeiro, Rio de Janeiro, Brazil

Assis IR (2010) Adsorção e disponibilidade de arse ˆnio em solos comdiferentes composiço ˜ es mineraló gicas. Thesis, Universidade

Federal de Viçosa, Viçosa, BrazilBaig JA, Kazi TG (2012) Translocation of arsenic contents invegetables from growing media of contaminated areas. Eco-toxicol Environ Saf 75:27–32

Baig JA, Kazi TG, Shah AQ, Arain MB, Afridi HI, Kandhro GA et al(2009) Optimization of cloud point extraction and solid phaseextraction methods for speciation of arsenic in natural waterusing multivariate technique. Anal Chim Acta 651:57–63

Beavington F, Cawse PA, Wakenshaw A (2004) Comparative studiesof atmospheric trace elements: improvements in air quality neara copper smelter. Sci Total Environ 332:39–49

Benin AL, Sargent JD, Dalton M, Roda S (1999) High concentrationsof heavy metals in neighborhoods near ore smelters in NorthernMexico. Environ Health Perspect 107:279–284

BorbaRP,FigueiredoBR,Matschullat J (2003)Geochemical distribution

of arsenic in waters, sediments and weathered gold mineralizedrocks from Iron Quadrangle, Brazil. Environ Geol 4:39–52Borba RP, Figueiredo BR, Cavalcanti JA (2004) Arse ˆnio na á gua

subterrâ nea em Ouro Preto e Mariana, Quadrila ´tero Ferrı´fero(MG). Rev Esc Minas 57:45–51

Bundschuh J, Litter MI, Parvez F, Roma ń-Ross G, Nicolli HB, JeanJS et al (2012) One century of arsenic exposure in LatinAmerica: a review of history and occurrence from 14 countries.Sci Total Environ 429:2–35

Canadian Council of Ministers of the Environment (1999) Canadiansediment quality guidelines for the protection of aquatic life:Arsenic. CCME, Winnipeg

Carabantes AG, de Fernicola NAGG (2003) Arse ńico en el á gua debebida: un problema de salud pu ´blica. Rev Bras Cieˆnc Farm39:365–372

Cebrian ME, Albores A, Aquilar M, Blakely E (1983) Chronic arsenicpoisoning in the North of Mexico. Hum Toxicol 2:121–133

Chakraborty AK, Saha KC (1987) Arsenical dermatosis fromtubewell water in West Bengal. Indian J Med Res 85:326–334

Chen SL, Dzeng SR, Yang MH, Chiu KH, Shich GM, Wai CM(1994) Arsenic species in groundwaters of the blackfootdisease area, Taiwan. Environ Sci Technol 28:877–881

Comitê da Sub-Bacia Hidrogra ća Mineira do Rio Paracatu (2005)Plano Diretor de Recursos Hı ´dricos da Bacia Hidrogra ća do RioParacatu. http://comites.igam.mg.gov.br/new/index.php?option=com_contentandtask=viewandid=875andItemid=819 . Accessed27 Mar 2014

Companhia de Pesquisa de Recursos Minerais (2003) Arse ˆnio. http:// www.cprm.gov.br/pgagem/puerto/arsenio.pdf . Accessed: 25 Fe-bruary 2014

Conselho Nacional do Meio Ambiente (2005) Resoluça õ 357 de 17 demarço de 2005—Dispo ˜e sobre a classicaça õ dos corpos d’a´guae diretrizes ambientais para o seu enquadramento, bem comoestabelece as condiço ˜ es e padrõ es de lançamento de euentes, edá outras provideˆncias. CONAMA, Brası ´lia

Conselho Nacional do Meio Ambiente (2008) Resoluça õ 396 de 03 deabril de 2008—Dispõe sobre a classicação e diretrizes ambi-entais para o enquadramento das a ´guas subterraˆneas e dá outrasprovidê ncias. Publicado no D.O.U. no 66 de 07 de abril de 2008,Seçã o I, 64-68

Costa Jú nior CN (1997) Caracterizaça õ mineraló gica dos diferentestipos de mine´rios e concentrado de otaça õ da mina Morro doOuro, Paracatu, MG. Dissertation, Universidade de Brası ´lia,Brasilia, Brazil

Csavina J, Field J, Taylor MP, Gao S, Landa ´zuri A, Betterton EA et al(2012) A review on the importance of metals and metalloids inatmospheric dust and aerosol from mining operations. Sci TotalEnviron 433:58–73

Cullen WR (2014) Chemical mechanism of arsenic biomethylation.Chem Res Toxicol 27:457–461

Deschamps E, Matschullat J (2007) Arse ˆnio antropogeˆnico enatural: Um estudo em regio ˜ es do Quadrila´tero Ferrı́ fero.Fundaçaõ Estadual de Meio Ambiente, Belo Horizonte

Deschamps E, Ciminelli VST, Lange FT, Matschullat J, Raue B,Schmidt H (2002) Soil and sediment geochemistry of the IronQuadrangle, Brazil. J Soil Sed 2:216–222

Empresa Brasileira de Pesquisa Agropecua ´ria (1997) Manual demé todos de aná lise de solo, 2nd edn. EMBRAPA, Rio de Janeiro

Farı́ as SS, Casa VA, Va ´squez C, Ferpozzi L, Pucci GN, Cohen IM(2003) Natural Contamination with arsenic and other traceelements in ground waters or Argentine Pampean Plain. SciTotal Environ 309:187–199

Figueiredo BR (2010) Mine ´rios e ambiente. Editora UNICAMP,Campinas

Figueiredo BR, Borba RP, Ange ´lica RS (2007) Arsenic occurrence in

Brazil and human exposure. Environ Geochem Health 29:109–118Goering PL, Aposhian HV, Mass MJ, Cebria ń M, Beck BD, Waalkes

MP (1999) The enigma of arsenic carcinogenesis: role of metabolism. Toxicol Sci 49:5–14

Gurgel BS (2007) Avaliaça õ de impactos ambientais por estudogeoquı́ mico na Bacia do Co´ rrego Rico, Paracatu–MG. Disser-tation, Universidade de Brası ´lia, Brasilia, Brazil

Hopenhayn-Rich C, Biggs ML, Kalman DA, Moore LE, Smith AH(1996) Arsenic methylation patterns before and after changefrom high to lower arsenic concentrations in drinking water.Environ Health Perspect 104:1200–1207


1 3

http://www.atsdr.cdc.gov/spl/resources/ATSDR_2011_SPL_Detailed_Data_Table.pdfhttp://www.atsdr.cdc.gov/spl/resources/ATSDR_2011_SPL_Detailed_Data_Table.pdfhttp://comites.igam.mg.gov.br/new/index.php?option=com_contentandtask=viewandid=875andItemid=819http://comites.igam.mg.gov.br/new/index.php?option=com_contentandtask=viewandid=875andItemid=819http://www.cprm.gov.br/pgagem/puerto/arsenio.pdfhttp://www.cprm.gov.br/pgagem/puerto/arsenio.pdfhttp://www.cprm.gov.br/pgagem/puerto/arsenio.pdfhttp://www.cprm.gov.br/pgagem/puerto/arsenio.pdfhttp://comites.igam.mg.gov.br/new/index.php?option=com_contentandtask=viewandid=875andItemid=819http://comites.igam.mg.gov.br/new/index.php?option=com_contentandtask=viewandid=875andItemid=819http://www.atsdr.cdc.gov/spl/resources/ATSDR_2011_SPL_Detailed_Data_Table.pdfhttp://www.atsdr.cdc.gov/spl/resources/ATSDR_2011_SPL_Detailed_Data_Table.pdf


14/15

Hopenhayn-Rich C, Biggs ML, Smith AH (1998) Lung and kidneycancer mortality associated with arsenic in drinking water inCórdoba, Argentina. Int J Epidemiol 27:561–569

Hunt KM, Srivastava RK, Elmets CA, Athar M (2014) Themechanistic basis of arsenicosis: pathogenesis of skin cancer.Cancer Lett 354:211–219

Instituto Mineiro de Gesta õ das Á guas (2010) Monitoramento daQualidade das a´guas superciais na Bacia do Rio Sa õ Franciscoe auentes em 2009—Relato ´ rio anual. IGAM, Belo Horizonte

Keng JCW, Uehara G (1974) Chemistry, mineralogy and taxonomy of oxysols and ultisols. Proc Soil Crop Sci Soc 33:119–126

Ladeira ACQ, Ciminelli VST (2000) Mobility of As(III) andAs(V) on soils. In: Young C (ed) Minor elements 2000. SME,Englewood, pp 191–198

Ladeira ACQ, Ciminelli VST (2004) Adsorption and desorption of arsenic on an oxisol and its constituents. Water Res 38:2087–2094

Liao VH, Chu Y, Su Y, Lin P, Hwang Y, Liu C et al (2011) Assessingthe mechanisms controlling the mobilization of arsenic in thearsenic contaminated shallow alluvial aquifer in the blackfootdisease endemic area. J Hazard Mater 197:397–403

Lomax C, Liu W, Wu L, Xue K, Xiong J, Zhou J et al (2012)Methylated arsenic species in plants originate from soilmicroorganisms. New Phytol 193:665–672

Machado PLOA, Campos AC, Santos FS (2003) Me ´todos de preparode amostras e de determinaça õ de carbono em solos tropicais.EMBRAPA, Rio de Janeiro

Maity S, Chakravarty S, Thakur P, Gupta KK, Bhattacharjee S, RoyBC (2004) Evaluation and standardization of a simple HG AASmethod for rapid speciation of As(III) and As(V) in somecontaminated groundwater samples of West Bengal, India.Chemosphere 54:1199–1206

Mandal BK, Suzuki KT (2002) Arsenic round the world: a review.Talanta 58:201–235

Matschullat J, Borba RP, Deschamps E, Figueiredo BR, Gabrio T,Schwenk M (2000) Human and environmental contamination inthe Iron Quadrangle, Brazil. Appl Geochem 15:181–190

Mello JWV, Roy WR, Talbott JL, Scott J, Stucki JW (2006)Mineralogy and arsenic mobility in arsenic-rich Brazilian soilsand sediments. J Soil Sed 6:9–19

Mello JWV, Talbott JL, Scott J, Roy WR, Stucki JW (2007) Arsenicspeciation in arsenic-rich Brazilian soils from gold mining sitesunder anaerobic incubation. Environ Sci Pollut Res 14:388–396

Monteiro LVS, Bittencourt JS, Juliani C, Oliveira TF (2006) Geology,petrography, and mineral chemistry of the Vazante non-suldeand Ambró sia and Fagundes sulde-rich carbonate-hosted Zn-(Pb) deposits, Minas Gerais, Brazil. Ore Geol Rev 28:201–234

Mulholland DS (2009) Geoquı ´mica aplicada a` avaliaçaõ da qualidadede sistemas aqua´ticos da Bacia do Rio Paracatu (MG). Disser-tation, Universidade de Brası ´lia, Brasilia, Brazil

Nguyen KP, Itoi R (2009) Source and release mechanism of arsenic inaquifers of Mekong Delta, Vietnam. J Contam Hydrol 103:58–69

Nguyen VA, Bang S, Viet PH, Kim KW (2009) Contamination of

groundwater and risk assessment for arsenic exposure in Hanamprovince, Vietnam. Environ Int 35:466–472Nickson RT, Macarthur JM, Burgess WG, Ahmed KM, Ravenscroft

P, Rahman M (1998) Arsenic poisoning in Bangladesh ground-water. Nature 395:338

Nickson RT, Macarthur JM, Ravenscroft P, Burgess WG, Ahmed KM(2000) Mechanism of arsenic release to groundwater, Bangla-desh and West Bengal. Appl Geochem 15:403–413

Nriagu JO (1994) Arsenic in the environment, part II: human healthand ecosystems. Wiley, New York, pp 1–16

Palmieri HEL (2006) Distribuiça õ, especiaça õ e transfereˆncia de Hg eAs para a biota em areas do sudeste do Quadrila ´tero Ferrı´fero,

MG. Thesis, Universidade Federal de Ouro Preto, Ouro Preto,Brazil

Pereira JC, Silva AK, Nalini HA Jr, Silva EP, Lena JC (2007)Distribuiça õ, fracionamento e mobilidade de elementos traço emsedimentos superciais. Quim Nova 30:1249–1255

Phuong NM, Kang Y, Sakurai K, Sugihara M, Kien CN, Bang NDet al (2012) Arsenic contamination in groundwater and itspossible sources in Hanam, Vietnam. Environ Monit Assess184:4501–4515

Rezende PS (2009) Avaliação da distribuição e mobilidade deelementos traço em sedimentos da Bacia Hidrogra ća do RioSão Francisco. Dissertation, Universidade Federal de MinasGerais, Belo Horizonte, Brazil

Rezende PS, Costa LM, Windmo ¨ ller CC (2013) Total and trivalentinorganic arsenic determination in water samples by selectivehydride generation atomic absorption spectrometry. Braz J AnalChem 10:429–435

Rodrigues LCV (2008) Estudo da disponibilidade quı ´mica de chumboe arsê nio em sedimentos de corrente e colunas de sedimentos noVale do Ribeira–SP. Thesis, Universidade Federal Fluminense,Niteró i, Brazil

Santos MJ (2012) O ouro e a diale ´tica territorial em Paracatu:Opulê ncia e Resisteˆncia. Dissertation, Universidade de Brası ´lia,Brasilia, Brazil

Segnini A, Santos LM, Silva WTL, Martin-Neto L, Borato CE, MeloWJ et al (2008) Estudo comparativo de me ´todos para adeterminaça õ da concentraça õ de carbono em solos com altosteores de Fe (latossolos). Quim Nova 31:94–97

Silva J, Mello JWV, Gasparon M, Abraha õ WAP, Ciminelli VST,Jong T (2010) The role of Al-goethites on arsenate mobility.Water Res 44:5684–5692

Silva J, Mello JWV, Gasparon M, Abraha õ WAP (2012) Effects oncompeting anions and iron bioreduction on arsenic desorption.Water Air Soil Pollut 223:5707–5717

Smith AH, Hopenhayn-Rich C, Bates MN, Goeden HM, Hertz-Picciotto I, Duggan HM et al (1992) Cancer risks from arsenic indrinking water. Environ Health Perspect 97:259–267

Sun F, Dempsey BA, Osseo-Asare KA (2012) As(V) and As(III)reactions on pristine and on surface-oxidized pyrite. J ColloidInterface Sci 388:170–175

Tannú s MB, Pimentel PF, Castro e Silva MEM, Moreira CVR,Oliveira EC (2001) Projeto Paracatu: Concepça õ e resultadospreliminares. Presented at Jornada Ambiental Sobre el ImpactoAmbiental del Mercurio Utilizado por la Minerı á Aurı́ feraArtesanal em Iberoame ´rica, Lima, Peru, September 26–28, 2001

Tseng WP, Chu HM, How SW, Fong JM, Lin CS, Yeh S (1968)Prevalence of skin cancer in and endemic area of chronicarsenicism in Taiwan. J Natl Cancer Inst 40:453–463

Tuzen M, Saygi KO, Karaman I, Soylak M (2010) Selectivespeciation and determination of inorganic arsenic in water, foodand biological samples. Food Chem Toxicol 48:41–46

United States Environmental Protection Agency (2001) Methods forcollection, storage and manipulation of sediments for chemical

and toxicological analyses: Technical manual. EPA 823-B-01-002. USEPA, Ofce of Water, Washington, DCUnited States Environmental Protection Authority, Australia (2007a)

EPA guideline: regulatory monitoring and testing water andwastewater sampling. USEPA, South Australia

United States Environmental Protection Authority, Australia (2007b)EPA guideline: regulatory monitoring and testing groundwatersampling. USEPA, South Australia

Vahter M (2002) Mechanisms of arsenic biotransformation. Toxicol-ogy 181:211–217

Vieira EC, Kamogawa MY, Lemos SG, No ´brega JA, Nogueira ARA(2005) Decomposiça õ de amostras de solos assistida por radiaça õ


1 3


15/15

micro-ondas: estrate ´gia para evitar a formaça ˜o de uoretosinsolú veis. Rev Bras Cie ˆnc Solo 29:547–553

Welch AH, Westjohn DB, Helsel DR, Wanty RB (2000) Arsenic inground water of the United States: occurrence and geochemistry.Ground Water 38:589–604

World Health Organization (2010) Exposure to arsenic: a majorpublic health concern. WHO, Geneva, Switzerland. http://www.who.int/ipcs/features/arsenic.pdf?ua=1 . Accessed 20 Nov 2013


1 3
http://www.who.int/ipcs/features/arsenic.pdf?ua=1http://www.who.int/ipcs/features/arsenic.pdf?ua=1http://www.who.int/ipcs/features/arsenic.pdf?ua=1http://www.who.int/ipcs/features/arsenic.pdf?ua=1

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