Research Article Risk Assessment of Heavy Metals ...downloads.hindawi.com/journals/bmri/2014/545473.pdf · Research Article Risk Assessment of Heavy Metals Contamination in Paddy

Research ArticleRisk Assessment of Heavy Metals Contamination in Paddy SoilPlants and Grains (Oryza sativa L) at the East Coast of India

Deepmala Satpathy1 M Vikram Reddy1 and Soumya Prakash Dhal2

1 Department of Ecology and Environmental Sciences Pondicherry University Pondicherry 605 014 India2Department of Physics Pondicherry University Pondicherry 605 014 India

Correspondence should be addressed to M Vikram Reddy venkateshsrinivas1gmailcom

Received 11 February 2014 Revised 7 May 2014 Accepted 8 May 2014 Published 3 June 2014

Academic Editor Young-Mi Lee

Copyright copy 2014 Deepmala Satpathy et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Heavy metals known to be accumulated in plants adversely affect human health This study aims to assess the effects ofagrochemicals especially chemical fertilizers applied in paddy fields which release potential toxic heavy metals into soil Thoseheavymetals get accumulated in different parts of paddy plant (Oryza sativaL) including the grains Concentrations of nonessentialtoxic heavymetals (Cd Cr and Pb) and themicronutrients (CuMn and Zn) were measured in the paddy field soil and plant partsMn andCd are found to be accumulatedmore in shoot than in rootThemetal transfer factors from soil to rice plant were significantfor Pb Cd Cu Cr Mn and ZnThe ranking order of bioaccumulation factor (BAF) for heavy metals was Zn gtMn gt Cd gt Cu gt Crgt Pb indicating that the accumulation of micronutrients was more than that of nonessential toxic heavy metalsThe concentrationsof heavy metals were found to be higher in paddy field soils than that of the nearby control soil but below permissible limits Thehigher Health Index (HI) values of rice consuming adults (1561) and children (1360) suggest their adverse health effects in the nearfuture

1 Introduction

Heavy metals from natural and anthropogenic sources accu-mulate in soil and plants and as a consequence representimportant environmental contamination problems Never-theless food safety issues and adverse health risks make thisone of the most serious environmental issues [1] Soils areconsidered to be an excellent media to monitor and assessheavy metal pollution because anthropogenic heavy metalsare usually deposited in the top soils [2] Heavy metal con-taminated soil adversely affects the whole ecosystem whenthese toxic heavy metals migrate into groundwater or aretaken up by flora and fauna which may result in great threatto ecosystems due to translocation and bioaccumulation [3]Heavy metals are potentially toxic to crop plants animalsand human beings when the contaminated soils are used forcrop production [4] Environmental contamination of thebiosphere with heavymetals due to intensive agricultural andother anthropogenic activities poses serious problems for safeuse of agricultural land [5] Contemporary agriculture with

indiscriminate use of agrochemicals such as fertilizers andpesticides along withmechanical cultivation for higher cropproductivity contaminates agriculture soils with potentiallynonessential and essential heavy metals [6 7] Human healthis directly affected through intake of crops grown in pollutedsoils There is clear evidence that human renal dysfunctionis related with contamination of rice with Cd in subsistencefarms in Asia [8] Indeed in Asia rice has been identifiedas one of the major sources of Cd and Pb for human beings[9ndash11] In Japan rice was found to be the main source of Cdcontamination in human beings [12]

It has also been reported that crop plants have differentabilities to absorb and accumulate heavy metals in theirbody parts and that there is a broad difference in metaluptake and translocation between plant species and evenbetween cultivars of the same plant species [13ndash20] Plantsabsorb heavy metals from the soil and the surface 25 cmzone of soil is mostly affected by such pollutants resultingfrom anthropogenic activities Heavy metals are adsorbedand accumulated in this soil layer probably due to relatively

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2 BioMed Research International

high organic matter The plant parts of interest for directtransfer of heavy metals to human body are the edible partssuch as the rice grain which may consequently becomea threat to human health Nevertheless heavy metals inthe environment consequently are of immense concernbecause of their persistence nature bioaccumulation andbiomagnification characters causing ecotoxicity to plantsanimals and human beings [21]

The micronutrients such as Zn Mn and Cu are requiredin small but critical concentrations for both plants andanimals and these have vital role in physical growth anddevelopment of crop plants such as paddy The deficiency ofZn in soil casts a conspicuous adverse effect with stuntedgrowth of crop plants like paddy and groundnut [22 23]reducing the overall productivity Generally the monitoringand assessment of total heavy metal concentrations in agri-cultural soils are required to evaluate the potential risk ofpaddy soils contaminated due to toxic heavy metalsmdashCd Asand Pb [7 24] Heavy metals are known to accumulate inliving organisms [25] There is a tendency of plants to takeup heavy metals that may subsequently transfer into the foodchainUse of polluted soil orwater for crop cultivationmainlyresults in decrease of overall productivity and contaminatesfood grains and vegetables which adversely affect humanhealth too [26] A number of reports on concentrations oftoxic metal such as Cd and Pb in rice and paddy soils inJapan China and Indonesia are available [27ndash31] Howeversuch studies are very few in India with little informationon toxic heavy metal contamination of paddy fields and riskassessment [32] though rice is the most important staplefood for Indian people The objectives of the present studytherefore are primarily risk assessment of potential toxic andnonessential heavymetalsmdashCd As Pb and Cr in the surfacesoil of paddy fields at the predominantly paddy-cultivatedarea nearby Kalpakkam (Tamil Nadu) Concentrations of thetoxic heavy metals were assessed in soil root shoot andgrains of paddy crop to assess the bioaccumulation factorand transfer factor Risk assessment was made assessing thepotential risk factor for the local residents consuming ricethe staple food

2 Materials and Methods

21 Study Site The study site is located at about 30 km awayfromPondicherry towards east on the East Coast Road (ECR)at Swarnabhoomi near Kalpakkam in Tamil Nadu India(12∘22101584021510158401015840 and 12∘21101584032410158401015840N to 80∘04101584036610158401015840 and 80∘04101584004210158401015840 E0 (Figure 1)) The agricultural watershed is of about50 ha and it is transected at one end by the ECR About30 ha of the watershed comprising of paddy fields appliedwith chemical fertilizers and pesticides shed their water intoadjacent rivulet which finally joins a small lagoon locatedtowards south-west About 20 ha of the paddy fields is onthe same plane as that of the rivulet from where the water istaken for irrigation of the fields Sampling of the soil and riceplants with grains was carried out during crop season (winter2012) in order to investigate the concentrations and spatialdistribution of potentially toxic heavy metals such as Pb Cd

Cu CrMn and Zn originated from the agricultural activitiesof the agriculture watershed The study site and samplinglocations of the study site are shown in Figure 1

211 Sampling of Soil Rice Plants and Grain and SamplePreparation Soil samples were collected from six differentsites of the paddy fields Out of these one was the controlsite where no crop cultivation was done and other five sites(S-1 S-2 S-3 S-4 and S-5) were selected from paddy fieldsAt each sampling site a composite of five soil samples wascollected separately by a random selection from each fieldfrom surface (0ndash15 cm soil layer) with a small core samplerand mixed to make one composite sample Samples werecollected from centre of the fields in order to avoid the edgeeffect Each soil sample of about 500mg was collected fromthe 0ndash15 cm layer which represented the plough layer Riceplant samples were collected from the corresponding soilsampling site of the paddy field for computing correlationsbetween heavy metal concentrations of soil and plant Allsoil and rice plants along with grain samples were kept inclean polyethylene bags and brought to the laboratory foranalyses During plant sampling it was ensured that plantsamples were of the same physiological age and identicalsize Paddy crop plants were collected andwashed thoroughlywith deionized water Paddy plant was cut and separated intoroot shoot and grain subsamples All subsamples were oven-dried at 60∘C for 24 h and the dried samples were weighedthen pulverized and stored in Petri dishes The soil sampleswere air-dried at room temperature for several days thenpulverized and sieved through a 01mm stainless steel meshRice grain samples were washed with deionized water andhulls were removedThe rice grain samples without hull wereoven-dried at 70∘C for 72 h and then ground with an agatemortar to fine powder

22 Sample Analysis Soil pH and conductivity were deter-mined by using a digital pH meter For heavy metal analysisone gm of soil and 1 g of rice grain samples were digestedafter adding 15mL of triacid mixture (HNO

3 H2SO4 and

HClO4in a 5 1 1 ratio) with three replicates at 80∘C until

a transparent solution was obtained [33] After cooling thedigested sample was diluted up to 30mL with 2 HNO

3

and concentrations of Pb Cd Cu Cr Mn and Zn weredetermined by AAS (GBC makemdashModel Avanta PM)

For plant samples 1 g of dried sample was digested withHNO

3and HClO

4in a 5 1 ratio until a transparent solution

was obtained and the plant digests were filtered and dilutedto 30mL with distilled water (Reddy et al) [32] The filtratesof plant were then assessed by using atomic absorptionspectroscopy (AAS GBC makemdashModel Avanta PM) foranalysis of Pb Cd Cu Cr Mn and Zn The AAS value ofblank (without sample) of each metal was deducted from thesample value for final calculations [26] All the analyses weredone with three replications

23 Bioaccumulation Factor (BAF) The BAF (bioaccumula-tion factor the ratio of the concentration of the element inthe grain to that in the corresponding soil) was calculated for

BioMed Research International 3

N

(Km)0 05 1 2

Odiyur lakeECRPaddy fieldRivuletSampling site

S1

S2

S3

S4

S5

Control

Bay of Bengal

Odiyur lake

Rivulet

80∘02998400E

80∘02998400E 80∘04998400E

80∘04998400E

12∘22

998400N

12∘20

998400N

12∘22

998400N

12∘20

998400N

Figure 1 Location of sampling area

each rice sample to quantify the bioaccumulation effect of riceon the uptake of heavy metals from the soils [34] The BAFwas computed as

BAF = CrCs (1)

where Cr and Cs represent the heavy metal concentrations inrice grain and soils respectively

24 Translocation Factor (TF) and Enrichment Factor (EF)Translocation factor (TF) or mobilization ratio [35 36] wascalculated to determine relative translocation of metals fromsoil to other parts (root shoot or grain) of the plant speciesas follows

TF

=

Concentration ofmetal in plant tissueConcentration ofmetal in corresponding soil or root or shoot

(2)

The enrichment factor (EF) has been calculated to derive thedegree of soil contamination and heavy metal accumulationin soil and in plants growing on contaminated site withrespect to soil and plants growing on uncontaminated soil[37] as follows

EF = Concentration ofmetals in soil at contaminated siteConcentration ofmetals in soil at uncontaminated site

(3)

25 Risk Assessment The Health Risk Index (HRI) wascalculated as the ratio of estimated exposure of rice and oralreference dose (ORD) [7] ORDs were 2 times 10minus2 1 times 10minus3and 4 times 10minus2 and 15mgkgday for Pb Cd Cu Cr andZn respectively [38 39] Estimated exposure is obtained bydividing the daily intake (DI) of heavy metals by their safelimits An index value gt1 is considered unsafe for humanhealth [39] DI was calculated by the following equation

DI = C times Con times EF times EDBw times AT

(4)

where C (in milligrams per kilogram) is the concentration ofheavy metals in the rice Con (in grams per person per day)is the daily average consumption of rice in the region Bw (inkilograms per person) represents bodyweight EF is exposurefrequency (365 daysyear) ED is exposure duration (70 yearsequivalent to the average lifespan) and AT is average time(365 daysyear number of exposure years assuming 70 yearsin this study) The average daily rice intake of adults andchildren was considered to be 3892 and 1984 gpersondayrespectively [40] Average adult and child body weights weretaken to be 559 and 327 kg respectively as used in manyprevious studies [7 40ndash42] The health risk for adult andchildren is considered separately since the contact pathwaywith each exposure way changes with age There may be acertain amount of discrepancy in health risk between agegroups and locality of inhabitants (Wang et al [41]) Harrisonand Chirgawi [43] reported that exposure of two or more


pollutants may result in additive or interactive effects Wanget al [41] Chien et al [44] Zheng et al [40] and Hang et al[7] have studied hazard index for different diets Assumingthe additive effect here HRI can therefore be summed acrossthe constituents to calculate the HI for a specific receptor(eg diet) combination The HI is calculated to evaluate thepotential risk of adverse health effects from a mixture ofchemical constituents in rice The HI was calculated throughdaily average consumption of rice for a human being (adultsand children) and is as follows

HI =119899

sum

119894=1

HRI (5)

26 Data Analysis Arithmetical means plusmn standard deviation(SD 119899 = 3) were used to assess the contamination levelsof heavy metals in soils root shoot and grains Coefficientcorrelation analysis was done to find out the heavy metalscharacteristics in agricultural field soil and grain samples

3 Results and Discussion

31 Heavy Metal Concentration in Soil It was found that inthe essential heavy metals in the paddy soil Mn concen-tration ranged from 125 to 539 120583g gminus1 Zn concentrationranged from 38 to 338 120583g gminus1 Cu concentration rangedfrom 003 to 29 120583g gminus1 in the paddy field soils and in theconcentrations of nonessential toxic metals Pb ranged from53 to 198 120583g gminus1 Cr ranged from 13 to 78 120583g gminus1 and Cdfrom 002 to 06 120583g gminus1 (Table 1) Among thesemetals Cd andCr are highly toxic while Pb is moderately toxic and Zn Mnand Cu are essential elements and micronutrients [45] Theranking order of occurrence of the heavy metals in the paddyfield soils was Mn gt Zn gt Pb gt Cr gt Cu gt Cd indicating thatMn followed by Zn was in the maximum concentrations andCd was in minimum concentration Concentrations of theheavy metals are higher in the paddy field soils compared tothat of nearby control field soil However the ranking orderof concentration of the metals is different from that of thepaddy soil (Cd gt Mn gt Zn gt Cu gt Pb) of a predominantlypaddy cultivated area at Bahour near Puducherry with Cd inmaximum concentration and Pb in minimum concentration[32] The concentrations of Pb and Cd were higher in S-5(198plusmn13 120583g gminus1 and 06plusmn004 120583g gminus1) respectively followedby S-4 (173plusmn09 120583g gminus1 and 05plusmn002 120583g gminus1) respectively theconcentrations of Pb were 149 plusmn 03 120583g gminus1 at S-2 and 117 plusmn06 120583g gminus1 at S-1 andCd concentrationwas (04plusmn0007 120583g gminus1)at S-1 showing the ranking order of Pb concentration inpaddy soil S-5 gt S-4 gt S-3 gt S-2 gt S-1 Concentration ofCd was higher in S-5 followed by S-4 S-3 and S-2 (02 plusmn003 120583g gminus1) showing the ranking order of S-5 gt S-4 gt S-3 gt S-1 gt S-2 which is attributable to spatial difference infertilizer broadcasting and consequential input on the soilsurface

Concentration of Cu was higher in S-2 (54 plusmn 15 120583g gminus1)followed by S-3 (43 plusmn 09 120583g gminus1) S-4 (30 plusmn 06 120583g gminus1) S-5 (29 plusmn 013 120583g gminus1) and S-1 (13 plusmn 04 120583g gminus1) showing the

ranking order of S-2 gt S-3 gt S-4 gt S-5 gt S-1 Concentration ofCr was higher in S-5 (78 plusmn 03 120583g gminus1) followed by S-4 (67 plusmn01 120583g gminus1) S-3 (40 plusmn 02 120583g gminus1) S-2 (36 plusmn 03 120583g gminus1) andS-1 (26 plusmn 01 120583g gminus1) showing the ranking order of S-2 gt S-3 gt S-4 gt S-5gt S-1 Concentration of Mn was higher in S-3 (442 plusmn 22 120583g gminus1) followed by S-2 (421 plusmn 16 120583g gminus1) S-4 (412 plusmn 53 120583g gminus1) S-5 (315 plusmn 15 120583g gminus1) and S-1 (125 plusmn55 120583g gminus1) showing the ranking order of S-3 gt S-2 gt S-4 gt S-5gt S-1 Concentration of Zn was higher in S-5 (338plusmn13 ppm)followed by S-4 (289plusmn55 120583g gminus1) S-2 (171plusmn09 120583g gminus1) S-3(148plusmn04 120583g gminus1) and S-1 (7plusmn02 120583g gminus1) showing the rankingorder of S-5 gt S-4 gt S-2 gt S-3 gt S-1

The toxic heavymetals Cd and Pb and themicronutrientsZn Cu andMn accumulated in the soil of paddy fields whichwas higher than that of the control soilTheheavymetals werein a ranking order of Mn gt Zn gt Pb gt Cr gt Cu gt Cd Theconcentrations of Pb Cd Cu Cr andZn in the paddy soils arecomparable to those for worldwide normal soils (ie withinthe range of published values) [46 47] Only concentrationof Mn was higher than the value of uncontaminated soilcritical soil concentration [48] and worldwide normal soils(Table 2)

32 Heavy Metal Concentration in Different Plant Parts Themean concentrations of heavymetals in the paddy plant parts(Table 1) showed that most of the metals accumulated morein the roots than in other plant parts shoots and grains andranged from 144ndash219120583g gminus1 for Mn 47ndash169120583g gminus1 for Zn36ndash53 120583g gminus1 for Pb 06ndash17120583g gminus1 for Cr 02ndash05 for Cuand 01-02120583g gminus1 for Cd among the five sites (Table 1) Itindicated that the Cd concentrations were minimum in thepaddy soil in contrast to the Cd concentrations of paddy soilat Bahour in Puducherry [32] The mean concentrations ofheavymetals in the paddy plant parts showed thatmost of themetals accumulated more in the roots than in other parts Ingeneral metal uptake was higher for the micronutrients Mnand Zn in the roots were followed by Pb Cr Cu and Cd Inthe present study concentration of Pb was found to be higherin roots that in shoots and grains Calluna vulgaris L Hull(common heather) and Agrostis vinealis harvested from anabandoned Pb mine in UK contained 320 and 2930mgkgdry wt respectively in shoot tissue while Pb values for rootwere 9610 and 9740mgkg indicating high plant availabilityof the Pb in the soil as well as its limited mobility inside theplant [49] Cu was also found to be more in roots than thatin shoots and grains which is in corroboration with findingsof earlier workers [50 51] Yang et al [52] reported thataccumulation of Cu was more in roots while a small fraction(10) of absorbed Cu was translocated to stem The Cu andZn accumulated at their highest concentration in roots ofthe rice plants followed by shoots and grains Most metalsFe Mn Zn and Cu that were found profusely in the paddyplants were the micronutrients that are required for variousenzyme activities and play important roles in photosynthesisand growth of the plant [53 54]

It was seen that Mn and Cd were accumulated more inshoot than in root and found in the ranges of 25ndash329 120583g gminus1


Table 1 Mean concentrations of heavy metals along with standard deviation in soil and different plant parts across the sampling sites

Heavy metalsSoil range Root range Shoot range Grain range(120583g gminus1) (120583g gminus1) (120583g gminus1) (120583g gminus1)

Pb 53 plusmn 04ndash198 plusmn 13 36 plusmn 02ndash53 plusmn 004 03 plusmn 001ndash12 plusmn 001 001 plusmn 0001ndash1 plusmn 002

Cd 002 plusmn 0005ndash06 plusmn 004 011 plusmn 0008ndash02 plusmn 001 02 plusmn 001ndash03 plusmn 001 002 plusmn 0001ndash005 plusmn 0002

Cu 003 plusmn 0004ndash54 plusmn 15 02 plusmn 002ndash05 plusmn 004 004 plusmn 0008ndash03 plusmn 003 01 plusmn 0008ndash03 plusmn 001

Cr 13 plusmn 001ndash78 plusmn 03 06 plusmn 002ndash17 plusmn 004 04 plusmn 001ndash09 plusmn 004 01 plusmn 002ndash06 plusmn 001

Mn 125 plusmn 02ndash539 plusmn 15 144 plusmn 09ndash219 plusmn 03 25 plusmn 28ndash329 plusmn 19 56 plusmn 004ndash75 plusmn 003

Zn 38 plusmn 17ndash338 plusmn 13 47 plusmn 01ndash169 plusmn 09 23 plusmn 001ndash6 plusmn 02 32 plusmn 005ndash72 plusmn 0008

Table 2 Mean values of heavy metals (Pb Cd Cu Cr Mn and Zn) for uncontaminated paddy soils mean values for worldwide normalsurface soils critical concentrations for contaminated soils Indian standards and European Union standards compared with the values ofpresent study

Elements(120583g gminus1)

Mean values forpaddy soilsa

Mean values forworldwide normalsurface soils b

Critical soilconcentrationc Indian standardsd

European Unionstandardse

(EU 2002) [69]Present study

Pb 233 22ndash44 100ndash400 250ndash500 300 53ndash198Cd 034 037ndash078 3ndash8 3ndash6 3 02ndash06Cu 207 13ndash24 60ndash125 135ndash270 140 110ndash29Cr 64 12ndash83 75ndash100 mdash mdash 13ndash78Mn 039 027ndash053 15ndash3 mdash mdash 125ndash339Zn 61 45ndash100 70ndash400 300ndash600 300 38ndash338aMean of total concentrations of elements in uncontaminated paddy soils Data are from Wong et al (2002) [4] Wang et al (2003) [66] Chandrajith et al(2005) [67]bMean of total concentrations of elements in the surface horizon of worldwide normal soil and normal means that the data do not include contaminated ormineralized soils Data are from Kabata-Pendias (2001) [46] Essington (2004) [68]cHigher concentrations may be toxic to plants depending on speciation (Alloway 1995) [48]dIndian standards (Awashthi 2000) [47] for agricultural soilseEuropean standards (EU 2002) [69] for agricultural soils

for Mn 23ndash6 120583g gminus1 for Zn 04minus09 120583g gminus1 for Cr 03ndash12 120583g gminus1 for Pb 02-03 120583g gminus1 for Cd and 005ndash03120583g gminus1 forCu among the five sites (Table 1) In the shoots concentra-tions of Mn and Cd were higher than their concentrations inroots and grains Jarvis Jones and Hopper [50] reported thatCd was easily taken up by plants and transported to differentparts although it is nonessential and is of no beneficial effectson plants and animals Moreover Cd is toxic to animalsand plants and plants when exposed to this metal showreduction in photosynthesis and uptake of water and nutrient[55] Higher concentration of Mn in leaves of both theplants indicated its high mobility [56] as leaf chlorophyllcontent requires Mn for photosynthesis In contrast Guptaand Sinha [57] reported higher accumulation of Mn in rootsfollowed by leaves inChenopodiumThemean concentrationsof heavy metals in the grains were found in the ranges of56ndash75 120583g gminus1 for Mn 32ndash72120583g gminus1 for Zn 01ndash06120583g gminus1 forCr 01ndash03 120583g gminus1 for Cu 002ndash005120583g gminus1 for Cd and 001ndash1 120583g gminus1 for Pb among the five sites (Table 1) In grains amongall metals Mn and Zn were in more elevated concentrationsthan Cr Cu Cd and Pb but their concentrations were

less compared to that of roots and shoots Concentrationof Zn ranged between 32 120583g gminus1 and 72 120583g gminus1 which didnot exceed the maximum permissible limit of 50 (Pilc et al)[58] Concentration of Pb ranged between 001 120583g gminus1 and1 120583g gminus1 The highest Pb content was found in S-4 (1120583g gminus1)and S-5 (09 120583g gminus1) which exceeds the values given byPilc et al [58] or the corresponding limit defined by theCommission Regulation Directive EC [59] However theconcentrations of Cr Cu and Cd ranged between 01 120583g gminus1and 06 120583g gminus1 01 120583g gminus1 and 02120583g gminus1 and 002 120583g gminus1 and005 120583g gminus1 respectively which did not exceed the valuesdefined by the Commission Regulation Directive EC [59]or the corresponding limits given by Pilc et al [58] andFAOWHO [60] (Table 3) Concentration of Cd was foundwithin the limit defined by CODEX [61] and European Com-mission [62] (Table 3) Table 3 lists the maximum allowableconcentrations (MAC) of Pb Cd Cu Cr and Zn in foodsrecommended by theChineseNational StandardAgencyThemean concentrations of all the elements in the rice grainwere below their maximum allowable levels except for PbThe results indicate that the concentration of Pb in rice grain


may have been affected by various anthropogenic activitiessuch as use of tractor for farming and use of chemicalfertilizers and pesticides Apart from this the agriculturalwatershed is transected on one end by ECR (East CoastRoad) a state highway (State Highway number 49) which isused by more than 10000 vehicles daily On the other endMaduvankarai Road a normal street road connecting theECR to the boat house via a bridge also serves as modeof transportation Both the roads may be contributing tothe increase of Pb concentration that may have come fromthe vehicular emission Boating fishing by motor boats andother recreational activities taking place nearby lagoon couldbe also a reason for elevated concentration of Pb in rice grainConcentration of Cr is slightly higher but below MAC Itmay be due to some anthropogenic activities such as useof chemical fertilizers and pesticides and other industrialactivities near Kalpakkam which comes as runoff and wouldtherefore reflect contamination by the element

33 Bioaccumulation Factor Bioaccumulation factors(BAFs) for the heavy metal transfer from soils to rice areshown in Figure 2 The BAF values of the heavy metals suchas Zn Mn Cd Cu Cr and Pb were found to be in the rangesof 02 to 05 01 to 02 005 to 02 004 to 01 004 to 007 and0001 to 006 respectively The trend in the BAF for heavymetals in the study sites was in the ranking order of Zn gtMn gt Cd gt Cu gt Cr gt Pb Among the heavy metals BAFvalues were found to be higher for Zn Mn and Cd whereasrelatively lower BAF values were found in Cu Cr and PbThefood chain (soil-plant-human) is mainly known as one of themajor pathways for exposure of human to soil contaminantsSoil-to-plant transfer is one of the key processes of humanexposure to toxic heavy metals through the food chain [63]When BCF lt 1 or BAF = 1 it denotes that the plant onlyabsorbs the heavy metal but does not accumulate whenBCF gt 1 and this indicates that plant accumulates the heavymetals BAF values of Pb Cd Cu Cr Mn and Zn were lessthan one in the rice grain which indicates that plants onlyabsorb the heavy metals

34 Translocation Factor Transfer factor is one of the maincomponents of human exposure to toxic heavy metalsthrough the food chain The transfer factors (TFs) of metalsfrom soil to root (TFSoil) root to shoot (TFRoot) and shootto grain (TFShoot) were calculated and given in Table 4 Theaverage translocation values ofmetals in paddy soils from soilto root (TFSoil) were found to be in the order of Zn (04 to09) gt Mn (03 to 07) gt Cd (03 to 06) gt Pb (02 to 04) gtCr (02 to 03) gt Cu (009 to 02) In the case of root (rootto shoot) TFRoot values were found in the order of Cd (13 to24) gt Mn (13 to 23) gt Cr (05 to 08) gt Cu (02 to 06) gtZn (02 to 05) gt Pb (007 to 03)The translocation values forshoot to grain (TFShoot) were found in the following order Cu(11 to 25) gt Zn (1 to 15) gt Pb (004 to 08) gt Cr (03 to 07)gtMn (02 to 03) gt Cd (009 to 02) There was a significantdifference in TFs values among the heavy metals (119875 lt 005)Soil-to-plant transfer factor is one of the major componentsof human exposure to metals through the food chain and

05

04

03

02

01

00

Bioa

ccum

ulat

ion

fact

or

S1 S2 S3 S4 S5Sampling sites

PbCdCu

CrMnZn

Figure 2 Bioaccumulation factor of the heavy metals across thesites

it could reveal bioavailability of heavy metals in investigatedsoilsThe higher the TF values are the more mobileavailablethe metals are [1 42 64] The TFs vary noticeably within theplant species even for an individual heavy metal [1] In thepresent study transfer of Cd and Zn from roots to shoots wasmore than other heavy metals as the concentrations of thesetwo were found to be more in shoots than that of roots andgrains Roots often contain more Zn than the shoot parts butthe Zn may be translocated from the roots and accumulatedin the plant shoot parts [46] Cd was also translocated morefrom root to shoot which is known to be relatively mobile inplants [46] The metal translocation process in plant speciesis a crucial factor in determining the metal distribution indifferent plant tissues [65]

35 Enrichment Factor The EFs of the paddy field soils forthe heavy metals were found to be in the ranges of Pb (22 to37) Cd (84 to 271) Cu (486 to 2043) Cr (2 to 62) Mn (33to 43) and Zn (19 to 9) and in the ranking order of Cu gtCd gt Zn gt Cr gtMn gt Pb Moreover there was a significantdifference in EFs values among the heavy metals (119875 lt 001)The EF values greater than 1 indicate higher availability anddistribution of metals in the contaminated soil subsequentlyincreasing themetal accumulation in plants species grown onthe soil [36 37] Among the metals estimated the maximalenrichment was found in case of Cu and Cd for the paddysoils (Figure 3)

36 Correlation Matrix The correlation coefficient matrix isnormally used to measure the degree of correlation betweenlogarithms of the elemental concentrations [70] and thismatrix for the heavy metals of paddy showed highly sig-nificant positive correlations between the pairs of elementsof soil samplesmdashCd-Pb (065) Cr-Pb (095) Zn-Pb (096)Cd-Cr (083) Cd-Zn (069) and Cr-Zn (098) (Table 5(a))Besides highly significant positive correlations were found


Table 3The total concentrations of Pb Cd Cu Cr Mn and Zn in rice (Oryza sativa L) samples from the experimental sites compared withthe standard values

Elements (120583g gminus1) 1 2 3 4 5 6 Present studyPb 02 mdash 10 mdash mdash 02 001ndash10Cd 01 mdash 015 04 02 02 002ndash005Cu mdash 10 mdash mdash mdash 10 01ndash023Cr mdash mdash mdash mdash mdash 10 013ndash056Mn mdash mdash mdash mdash mdash mdash 558ndash747Zn mdash mdash 50 mdash mdash 50 323ndash724Maximum permitted levels for heavy metals in food crops (1) Commission Regulation Directive EC (2001) [59] (2) FAOWHO (1992) [60] (3) Pilc et al(1994) [58] (4) CODEX Alimentarius Commission (2006) [61] and (5) European Food Safety Authority EFSA [62](6) maximum levels of contaminants in foods (GB 13106-1991 GB 2762-2005 GB 15199-1994 GB 4810-1994) [7]

Table 4 Ranges of the translocation factors of the heavy metals from soil to root root to shoot and shoot to grain across the sampling sites

Heavy metals Tf (soil to root) Tf (root to shoot) Tf (shoot to grain)Pb 02ndash04 01ndash03 004ndash08Cd 02ndash06 14ndash24 01-02Cu 01-02 02ndash06 11ndash25Cr 02-03 05ndash08 03ndash07Mn 03ndash07 13ndash23 02-03Zn 04ndash09 03ndash05 1ndash15

250

200

150

100

50

0

Enric

hmen

t fac

tor


PbCdCu

CrMnZn

Figure 3 Enrichment factor of the heavy metals in soil across thesites

between the pairs of elements present in grains which arePb-Cd (092) Pb-Cu (075) Cr-Pb (073) Mn-Pb (096) Cd-Cr (091) Mn-Cd (098) Zn-Cd (071) Cr-Mn (085) andCr-Zn (072) (Table 5(b))The significant positive correlationbetween the elements of surface soil grains suggests that theircommon source of origin is probably the agrochemicals suchas phosphate and nitrate fertilizers broadcasted in the paddyfields [32]

37 Potential Health Risk of Heavy Metals through Rice IntakeRice consumption has been identified as one of the majorpathways of human exposure to the toxic heavy metals accu-mulated in rice grain Table 6 showed the dietary intake (DI)of heavy metals via rice for adults and children in the studyregion as the local people consume generally rice the staplefood for the people available in the regionThe DIs of Pb CdCu Cr and Zn through rice were estimated to be 402 027166 198 and 3704mgkgday for adults and 350 023 145173 and 3228mgkgday for children respectively The DIsof heavy metals for adults were found to be higher than thosefor children This is most probably due to relatively higherquantity of rice consumption of adults compared to the chil-dren which increased theDIs of heavymetalsThe result is inconformity with previous studies in the neighboring countryChina [40 71]

The HRIs of heavy metals through rice consumption aregiven in Table 4 The HRI of heavy metals for adults fromrice consumption was in decreasing order Zn gt Pb gt Cr gtCd gt Cu The HRI of heavy metals for children also has thesimilar trend as the adults The Zn has the highest HRI valueas it is an essential micronutrient Hence it may not pose apotential risk up to a certain concentration but may causeadverse effects at certain elevated level So among the toxicheavy metals Pb ingestion has the highest potential healthrisk of adverse effects for adults and children andCu ingestionhas minimum risk Only HRI of Zn for adults was foundbeyond the value of 1Therefore the health risk of singlemetalexposure through rice consumptionwas generally assumed tobe safe for the people of the regionHowever local inhabitantsmay be at risk due to the combination of several toxic heavy


Table 5 (a) Correlation of the heavy metals in paddy field soil (b) Correlation of the heavy metals in grains

(a)

Pb Cd Cu Cr Mn ZnPb 1Cd 0654123 1Cu 0193626 minus061182 1Cr 0952659 0802794 minus006512 1Mn 0316071 0273936 0032893 0175871 1Zn 0967693 0699247 0079194 0984368 0192237 1

(b)

Pb Cd Cu Cr Mn ZnPb 1Cd 0924811 1Cu 0759248 0629072 1Cr 0733659 0915057 0267458 1Mn 0968289 0988837 0716005 0850878 1Zn 0447148 0719954 042386 0722836 064716 1

Table 6 Health risk assessment of heavy metals via intake of rice

Individuals Element ORD DI HRI HI

Adults

Pb 350 402 0269

1561Cd 100 027 0042Cu 4000 166 0001Cr 150000 198 0123Zn 30000 3704 1126

Children

Pb 350 350 0234

1360Cd 100 023 0036Cu 4000 145 0001Cr 150000 173 0108Zn 30000 3228 0981

ORD oral reference dose (in micrograms per kilogram per day) DI daily intake (in micrograms per kilogram per day)

metals [71] The HI values for rice consumption of adultsand children were 1561 and 1360 respectively This indicatesthat adults and children may experience poor health effectsin the near future as the heavy metal accumulation over aperiod of time leads to biomagnification Our assessment wasonly to measure the intake of toxic heavy metals throughrice consumption In fact humans are also exposed to heavymetals through other foodspathways such as consumptionof contaminated vegetables fruits fish meat water and milk[40 41 72 73]Moreover theremay be the other sources suchas dust inhalation and dermal contact [74 75]

4 Conclusion

Thepresent study carried out on paddy fields nearKalpakkamin Tamil Nadu South India determined the accumulationof essential and nonessential heavy metals in paddy soils aswell as in rice plants including paddy grains Theoccurrenceof heavy metals in paddy field soils was in a ranking orderof Mn gt Zn gt Pb gt Cr gt Cu gt Cd Concentrations of the

heavy metals were higher in paddy field soils compared withthe control soil However the concentrations of Pb Cd CuCr and Zn except for Mn in the paddy soils were comparableto those of worldwide normal soils which were higher thanthe value of uncontaminated soil The uptake of Mn and Znwas higher in the roots of paddy plants which were followedby Pb Cr Cu and Cd Mn and Cd accumulated more inthe shoots than in roots and grains Pb content in grainsexceeded themaximumpermissible value in S-4 and all othermetals were below the safe limits Estimations showed thatDIs of heavy metals for adults were found to be higher thanthose for children which was most probably due to relativelyhigher quantity intake by adults In general no HRI valueswere gt1 through rice consumption except for Zn for adultsThe HRI values for both adults and children were 1561 and1360 respectively indicating that both adults and childrenmay experience some adverse health effects in the futuresince chemical fertilizers and pesticides are indiscriminatelyused by Indian farmers which are probably the main sourcesof the toxic heavy metals accumulated in the paddy fieldsOrganic agriculture with little use of agrochemicals could be


the alternative solution for reducing the contamination oftoxic heavy metals particularly the toxic Cd Cr and Pb inthe paddy fields producing rice the staple food in India andother Southeast Asian countries

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The present research was funded through a major ResearchProject (MRPF no 40-1372011 (SR) dated 04-07-2011)funded by University Grants Commission (UGC) (NewDelhi) Ms Deepmala Satpathy received a project researchfellowship from the MRP

References

[1] Y-J Cui Y-G Zhu R-H Zhai et al ldquoTransfer of metals fromsoil to vegetables in an area near a smelter in Nanning ChinardquoEnvironment International vol 30 no 6 pp 785ndash791 2004

[2] P K Govil G L N Reddy and A K Krishna ldquoContaminationof soil due to heavy metals in the Patancheru industrial devel-opment area Andhra Pradesh Indiardquo Environmental Geologyvol 41 no 3-4 pp 461ndash469 2002

[3] G R Bhagure and S R Mirgane ldquoHeavy metal concentrationsin groundwaters and soils of Thane Region of MaharashtraIndiardquo Environmental Monitoring and Assessment vol 173 no1ndash4 pp 643ndash652 2011

[4] S C Wong X D Li G Zhang S H Qi and Y S MinldquoHeavy metals in agricultural soils of the Pearl River DeltaSouth Chinardquo Environmental Pollution vol 119 no 1 pp 33ndash442002

[5] K Fytianos G Katsianis P Triantafyllou and G ZachariadisldquoAccumulation of heavy metals in vegetables grown in anindustrial area in relation to soilrdquo Bulletin of EnvironmentalContamination and Toxicology vol 67 no 3 pp 423ndash430 2001

[6] J Liu C-Q Duan Y-N Zhu X-H Zhang and C-X WangldquoEffect of chemical fertilizers on the fractionation of Cu Cr andNi in contaminated soilrdquo Environmental Geology vol 52 no 8pp 1601ndash1606 2007

[7] X Hang H Wang J Zhou C Ma C Du and X Chen ldquoRiskassessment of potentially toxic element pollution in soils andrice (Oryza sativa) in a typical area of the Yangtze River DeltardquoEnvironmental Pollution vol 157 no 8-9 pp 2542ndash2549 2009

[8] R L Chaney J S Angle M S McIntosh et al ldquoUsing hyperac-cumulator plants to phytoextract soil Ni and Cdrdquo Zeitschrift furNaturforschung C vol 60 no 3-4 pp 190ndash198 2005

[9] S Shimbo Z-W Zhang TWatanabe et al ldquoCadmium and leadcontents in rice and other cereal products in Japan in 1998-2000rdquo Science of the Total Environment vol 281 no 1ndash3 pp165ndash175 2001

[10] M-K Zhang and Z-X Ke ldquoHeavy metals phosphorus andsome other elements in urban soils of Hangzhou City ChinardquoPedosphere vol 14 no 2 pp 177ndash185 2004

[11] C Fangmin Z Ningchun X Haiming et al ldquoCadmium andlead contamination in japonica rice grains and its variationamong the different locations in southeast Chinardquo Science of theTotal Environment vol 359 no 1ndash3 pp 156ndash166 2006

[12] T Tsukahara T Ezaki J Moriguchi et al ldquoRice as the mostinfluential source of cadmium intake among general Japanesepopulationrdquo Science of the Total Environment vol 305 no 1ndash3pp 41ndash51 2003

[13] H Kurz ldquoSelection of cultivars to reduce the concentration ofcadmium and thallium in food and fodder plantsrdquo Journal ofPlant Nutrition and Soil Science vol 162 no 3 pp 323ndash3281999

[14] T Arao and N Ae ldquoGenotypic variations in cadmium levels ofrice grainrdquo Soil Science and Plant Nutrition vol 49 no 4 pp473ndash479 2003

[15] K Q Li J G Liu and X L Lu ldquoUptake and distributionof cadmium in different rice cultivarsrdquo Agro-EnvironmentalScience vol 22 pp 529ndash532 2003 (Chinese)

[16] Z W Li Y L Zhang G X Pan J M Li X M Huang and J FWang ldquoGrain contents of Cd Cu and Se by 57 rice cultivars andthe risk significance for human dietary uptakerdquo EnvironmentalScience vol 24 pp 112ndash115 2003 (Chinese)

[17] J G Liu K Q Li J K Xu J S Liang X L Lu and J L YangldquoInteraction of Cd and five mineral nutrients for uptake andaccumulation in different rice cultivars and genotypesrdquo FieldCrops Research vol 83 no 3 pp 271ndash281 2003

[18] J G Liu J S Liang K Q Li et al ldquoCorrelations between cad-mium andmineral nutrients in absorption and accumulation invarious genotypes of rice under cadmium stressrdquo Chemospherevol 52 no 9 pp 1467ndash1473 2003

[19] J G Liu Q S Zhu Z J Zhang J K Xu J C Yang and MH Wrong ldquoVariations in cadmium accumulation among ricecultivars and types and the selection of cultivars for reducingcadmium in the dietrdquo Journal of the Science of Food andAgriculture vol 85 no 1 pp 147ndash153 2005

[20] H Yu J Wang W Fang J Yuan and Z Yang ldquoCadmium accu-mulation in different rice cultivars and screening for pollution-safe cultivars of ricerdquo Science of the Total Environment vol 370no 2-3 pp 302ndash309 2006

[21] B J Alloway ldquoSoil factors associated with zinc deficiency incrops and humansrdquo Environmental Geochemistry and Healthvol 31 no 5 pp 537ndash548 2009

[22] T Arao S Ishikawa M Murakami K Abe Y Maejima and TMakino ldquoHeavy metal contamination of agricultural soil andcountermeasures in Japanrdquo Paddy and Water Environment vol8 no 3 pp 247ndash257 2010

[23] ldquoDeficiency in soil mars farming Green Revolution-II OrissaPost (Bhubaneswar)rdquo November 2011

[24] M Karatas S Dursun E Guler C Ozdemir and M EminArgun ldquoHeavy metal accumulation in wheat plants irrigated bywaste waterrdquo Cellulose Chemistry and Technology vol 40 no 7pp 575ndash579 2007

[25] R Singh D P Singh N Kumar S K Bhargava and S CBarman ldquoAccumulation and translocation of heavy metals insoil and plants from fly ash contaminated areardquo Journal ofEnvironmental Biology vol 31 no 4 pp 421ndash430 2010

[26] R Masironi S R Koirtyohann and J O Pierce ldquoZinc coppercadmium and chromium in polished and unpolished ricerdquoScience of the Total Environment vol 7 no 1 pp 27ndash43 1977

[27] S Suzuki N Djuangshi K Hyodo and O SoemarwotoldquoCadmium copper and zinc in rice produced in Javardquo Archivesof Environmental Contamination and Toxicology vol 9 no 4pp 437ndash449 1980

[28] S Suzuki and S Iwao ldquoCadmium copper and zinc levels inthe rice and rice field soil of Houston Texasrdquo Biological TraceElement Research vol 4 no 1 pp 21ndash28 1982


[29] I F Rivai H Koyama and S Suzuki ldquoCadmium contentin rice and its daily intake in various countriesrdquo Bulletin ofEnvironmental Contamination and Toxicology vol 44 no 6 pp910ndash916 1990

[30] M S Fazeli F Khosravan M Hossini S Sathyanarayan andP N Satish ldquoEnrichment of heavy metals in paddy cropsirrigated by paper mill effluents near Nanjangud Mysoredistrict Karnatake Indiardquo Environmental Geology vol 34 no4 pp 297ndash302 1998

[31] N Herawati S Suzuki K Hayashi I F Rivai and H KoyamaldquoCadmium copper and zinc levels in rice and soil of JapanIndonesia and China by soil typerdquo Bulletin of EnvironmentalContamination and Toxicology vol 64 no 1 pp 33ndash39 2000

[32] M V Reddy D Satpathy and K S Dhiviya ldquoAssessmentof heavy metals (CD and Pb) and micronutrirnts (Cu Mnand Zn) of paddy (Oryza sativa L) field surface soil andwater in a predominantly paddy-cultivated area at Puducherry(Pondicherry India) and effects of the agricultural runoff onthe elemental concentrations of a receiving rivuletrdquo Environ-mental Monitoring and Assessment vol 185 pp 6693ndash67042013

[33] S E Allen H M Grimshaw and A P Rowland ldquoChemicalanalysisrdquo in Methods in Plant Ecology P D Moore and S BChapman Eds pp 285ndash344 Blackwell London UK 1986

[34] H Liu A Probst and B Liao ldquoMetal contamination of soils andcrops affected by the Chenzhou leadzinc mine spill (HunanChina)rdquo Science of the Total Environment vol 339 no 1ndash3 pp153ndash166 2005

[35] S C Barman R K Sahu S K Bhargava and C ChaterjeeldquoDistribution of heavy metals in wheat mustard and weedgrown in field irrigated with industrial effluentsrdquo Bulletin ofEnvironmental Contamination and Toxicology vol 64 no 4 pp489ndash496 2000

[36] S Gupta S Nayek R N Saha and S Satpati ldquoAssessment ofheavy metal accumulation in macrophyte agricultural soil andcrop plants adjacent to discharge zone of sponge iron factoryrdquoEnvironmental Geology vol 55 no 4 pp 731ndash739 2008

[37] G C Kisku S C Barman and S K Bhargava ldquoContaminationof soil and plants with potentially toxic elements irrigated withmixed industrial effluent and its impact on the environmentrdquoWater Air and Soil Pollution vol 120 no 1-2 pp 121ndash137 2000

[38] US Environmental Protection Agency (USEPA) Exposure Fac-tors Handbook-General Factors EPA600P-95002Fa vol IOffice of Research and Development National Center forEnvironmental Assessment Washington DC USA 1997

[39] US Environmental Protection Agency (USEPA) Region 9Preliminary RemediationGoals USEPAWashingtonDCUSA2002

[40] N Zheng Q Wang X Zhang D Zheng Z Zhang and SZhang ldquoPopulation health risk due to dietary intake of heavymetals in the industrial area of Huludao city Chinardquo Science ofthe Total Environment vol 387 no 1ndash3 pp 96ndash104 2007

[41] X Wang T Sato B Xing and S Tao ldquoHealth risks of heavymetals to the general public in Tianjin China via consumptionof vegetables and fishrdquo Science of the Total Environment vol 350no 1ndash3 pp 28ndash37 2005

[42] S Khan Q Cao Y M Zheng Y Z Huang and Y G ZhuldquoHealth risks of heavy metals in contaminated soils and foodcrops irrigated with wastewater in Beijing Chinardquo Environmen-tal Pollution vol 152 no 3 pp 686ndash692 2008

[43] R M Harrison and M B Chirgawi ldquoThe assessment of air andsoil as contributors of some trace metals to vegetable plants

III Experiments with field-grown plantsrdquo Science of the TotalEnvironment vol 83 no 1-2 pp 47ndash62 1989

[44] L-C Chien T-C Hung K-Y Choang et al ldquoDaily intake ofTBT Cu Zn Cd and As for fishermen in Taiwanrdquo Science of theTotal Environment vol 285 no 1ndash3 pp 177ndash185 2002

[45] N C Brady and R R Weil The Nature and Properties of SoilPrentice-Hall Upper Saddle River NJ USA 13th edition 2002

[46] A Kabata-Pendias Trace Elements in Soils and Plants CRCPress Boca Raton Fla USA 2001

[47] S K Awashthi Prevention of Food Adulteration Act No 37 of1954 Central and State Rules as Amended for 1999 Ashoka LawHouse New Delhi India 2000

[48] B J Alloway ldquoThe origins of heavy metals in soilsrdquo in HeavyMetals in Soils B J Alloway Ed pp 29ndash39 Chapman amp HallLondon UK 1995

[49] J Pichtel and C A Salt ldquoVegetative growth and trace metalaccumulation on metalliferous wastesrdquo Journal of Environmen-tal Quality vol 27 no 3 pp 618ndash624 1998

[50] S C Jarvis L H P Jones and M J Hopper ldquoCadmium uptakefrom solution by plants and its transport from roots to shootsrdquoPlant and Soil vol 44 no 1 pp 179ndash191 1976

[51] L Leita M De Nobili C Mondini and M T Baca GarcialdquoResponse of Leguminosae to cadmium exposurerdquo Journal ofPlant Nutrition vol 16 no 10 pp 2001ndash2012 1993

[52] X-E Yang X-X Long W-Z Ni et al ldquoAssessing copperthresholds for phytotoxicity and potential dietary toxicity inselected vegetable cropsrdquo Journal of Environmental Science andHealth B vol 37 no 6 pp 625ndash635 2002

[53] R M Tripathi R Raghunath and T M KrishnamoorthyldquoDietary intake of heavy metals in Bombay city Indiardquo Scienceof the Total Environment vol 208 pp 149ndash159 1997

[54] W G Hopkins Introduction to Plant Physiology John Wiley ampSons New York NY USA 2nd edition 1999

[55] L Sanita Di Toppi and R Gabbrielli ldquoResponse to cadmium inhigher plantsrdquo Environmental and Experimental Botany vol 41no 2 pp 105ndash130 1999

[56] M S Li Y P Luo and Z Y Su ldquoHeavy metal concentrations insoils and plant accumulation in a restoredmanganeseminelandin Guangxi South Chinardquo Environmental Pollution vol 147 no1 pp 168ndash175 2007

[57] A K Gupta and S Sinha ldquoPhytoextraction capacity of theChenopodium album L grown on soil amended with tannerysludgerdquo Bioresource Technology vol 98 no 2 pp 442ndash4462007

[58] L Pilc J Rosada and J Siepak ldquoHeavy metals concentration insoil water and plants in the emission region of copper foundrylsquoGłogowrsquordquo Materiaty Sesji Naukowej Instytutu Ochrony Roslinvol 2 pp 228ndash232 1994

[59] Commission Regulation Directive EC Commission Regulation(EC) no 466 Official Journal of the European Communities2001

[60] FAOWHO Cadmium (EHC no 134) Geneva Switzerland1992

[61] CODEXAlimentarius commission joint FAOWHOfood stan-dards programme Report of the thirty ninth session interna-tional conference centre CODEX Geneva Switzerland 2006

[62] European Food Safety Authority EFSA ldquoScientific opinion-Cadmium in foodscientific opinion of the panel on contami-nants in the food chainrdquo EFSA Journal vol 980 pp 1ndash139


[63] P Zhuang M B McBride H Xia N Li and Z Li ldquoHealthrisk from heavy metals via consumption of food crops in thevicinity of Dabaoshan mine South Chinardquo Science of the TotalEnvironment vol 407 no 5 pp 1551ndash1561 2009

[64] J R Dean Bioavailability Bioaccessibility and Mobility ofEnvironmental Contaminants JohnWiley amp Sons London UK1st edition 2007

[65] Z-T Xiong ldquoLead uptake and effects on seed germination andplant growth in a Pb hyperaccumulator Brassica pekinensisRuprrdquo Bulletin of Environmental Contamination and Toxicologyvol 60 no 2 pp 285ndash291 1998

[66] X C Wang W D Yan Z An et al ldquoStatus of trace elements inpaddy soil and sediment in Taihu Lake regionrdquo Chemospherevol 50 no 6 pp 707ndash710 2003

[67] R Chandrajith C B Dissanayake and H J Tobschall ldquoTheabundances of rarer trace elements in paddy (rice) soils of SriLankardquo Chemosphere vol 58 no 10 pp 1415ndash1420 2005

[68] M E Essington Soil and Water Chemistry An IntegrativeApproach CRC Press Boca Raton Fla USA 2004

[69] European Union Heavy metals in wastes European Commis-sion on Environment 2002 httpeceuropaeuenvironmentwastestudiespdfheavy metalsreportpdf

[70] R Garcia and E Millan ldquoAssessment of Cd Pb and Zncontamination in roadside soils and grasses from Gipuzkoa(Spain)rdquo Chemosphere vol 37 no 8 pp 1615ndash1625 1998

[71] J Liu X-H Zhang H Tran D-Q Wang and Y-N ZhuldquoHeavy metal contamination and risk assessment in waterpaddy soil and rice around an electroplating plantrdquo Environ-mental Science and Pollution Research vol 18 no 9 pp 1623ndash1632 2011

[72] N Sridhara Chary C T Kamala and D Samuel Suman RajldquoAssessing risk of heavy metals from consuming food grownon sewage irrigated soils and food chain transferrdquo Ecotoxicologyand Environmental Safety vol 69 no 3 pp 513ndash524 2008

[73] E Sipter E Rozsa K Gruiz E Tatrai and V Morvai ldquoSite-specific risk assessment in contaminated vegetable gardensrdquoChemosphere vol 71 no 7 pp 1301ndash1307 2008

[74] D Grasmuck and R W Scholz ldquoRisk perception of heavymetal soil contamination by high-exposed and low-exposedinhabitants the role of knowledge and emotional concernsrdquoRisk Analysis vol 25 no 3 pp 611ndash622 2005

[75] L Hellstrom B Persson L Brudin K P Grawe I Oborn andL Jarup ldquoCadmium exposure pathways in a population livingnear a battery plantrdquo Science of the Total Environment vol 373no 2-3 pp 447ndash455 2007

Submit your manuscripts athttpwwwhindawicom

PainResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

ToxinsJournal of

VaccinesJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AntibioticsInternational Journal of

ToxicologyJournal of


StrokeResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Drug DeliveryJournal of



Advances in Pharmacological Sciences

Tropical MedicineJournal of


Medicinal ChemistryInternational Journal of


AddictionJournal of



BioMed Research International

Emergency Medicine InternationalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Autoimmune Diseases


Anesthesiology Research and Practice

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of


Pharmaceutics


MEDIATORSINFLAMMATION

of


high organic matter The plant parts of interest for directtransfer of heavy metals to human body are the edible partssuch as the rice grain which may consequently becomea threat to human health Nevertheless heavy metals inthe environment consequently are of immense concernbecause of their persistence nature bioaccumulation andbiomagnification characters causing ecotoxicity to plantsanimals and human beings [21]

The micronutrients such as Zn Mn and Cu are requiredin small but critical concentrations for both plants andanimals and these have vital role in physical growth anddevelopment of crop plants such as paddy The deficiency ofZn in soil casts a conspicuous adverse effect with stuntedgrowth of crop plants like paddy and groundnut [22 23]reducing the overall productivity Generally the monitoringand assessment of total heavy metal concentrations in agri-cultural soils are required to evaluate the potential risk ofpaddy soils contaminated due to toxic heavy metalsmdashCd Asand Pb [7 24] Heavy metals are known to accumulate inliving organisms [25] There is a tendency of plants to takeup heavy metals that may subsequently transfer into the foodchainUse of polluted soil orwater for crop cultivationmainlyresults in decrease of overall productivity and contaminatesfood grains and vegetables which adversely affect humanhealth too [26] A number of reports on concentrations oftoxic metal such as Cd and Pb in rice and paddy soils inJapan China and Indonesia are available [27ndash31] Howeversuch studies are very few in India with little informationon toxic heavy metal contamination of paddy fields and riskassessment [32] though rice is the most important staplefood for Indian people The objectives of the present studytherefore are primarily risk assessment of potential toxic andnonessential heavymetalsmdashCd As Pb and Cr in the surfacesoil of paddy fields at the predominantly paddy-cultivatedarea nearby Kalpakkam (Tamil Nadu) Concentrations of thetoxic heavy metals were assessed in soil root shoot andgrains of paddy crop to assess the bioaccumulation factorand transfer factor Risk assessment was made assessing thepotential risk factor for the local residents consuming ricethe staple food

2 Materials and Methods

21 Study Site The study site is located at about 30 km awayfromPondicherry towards east on the East Coast Road (ECR)at Swarnabhoomi near Kalpakkam in Tamil Nadu India(12∘22101584021510158401015840 and 12∘21101584032410158401015840N to 80∘04101584036610158401015840 and 80∘04101584004210158401015840 E0 (Figure 1)) The agricultural watershed is of about50 ha and it is transected at one end by the ECR About30 ha of the watershed comprising of paddy fields appliedwith chemical fertilizers and pesticides shed their water intoadjacent rivulet which finally joins a small lagoon locatedtowards south-west About 20 ha of the paddy fields is onthe same plane as that of the rivulet from where the water istaken for irrigation of the fields Sampling of the soil and riceplants with grains was carried out during crop season (winter2012) in order to investigate the concentrations and spatialdistribution of potentially toxic heavy metals such as Pb Cd

Cu CrMn and Zn originated from the agricultural activitiesof the agriculture watershed The study site and samplinglocations of the study site are shown in Figure 1

211 Sampling of Soil Rice Plants and Grain and SamplePreparation Soil samples were collected from six differentsites of the paddy fields Out of these one was the controlsite where no crop cultivation was done and other five sites(S-1 S-2 S-3 S-4 and S-5) were selected from paddy fieldsAt each sampling site a composite of five soil samples wascollected separately by a random selection from each fieldfrom surface (0ndash15 cm soil layer) with a small core samplerand mixed to make one composite sample Samples werecollected from centre of the fields in order to avoid the edgeeffect Each soil sample of about 500mg was collected fromthe 0ndash15 cm layer which represented the plough layer Riceplant samples were collected from the corresponding soilsampling site of the paddy field for computing correlationsbetween heavy metal concentrations of soil and plant Allsoil and rice plants along with grain samples were kept inclean polyethylene bags and brought to the laboratory foranalyses During plant sampling it was ensured that plantsamples were of the same physiological age and identicalsize Paddy crop plants were collected andwashed thoroughlywith deionized water Paddy plant was cut and separated intoroot shoot and grain subsamples All subsamples were oven-dried at 60∘C for 24 h and the dried samples were weighedthen pulverized and stored in Petri dishes The soil sampleswere air-dried at room temperature for several days thenpulverized and sieved through a 01mm stainless steel meshRice grain samples were washed with deionized water andhulls were removedThe rice grain samples without hull wereoven-dried at 70∘C for 72 h and then ground with an agatemortar to fine powder

22 Sample Analysis Soil pH and conductivity were deter-mined by using a digital pH meter For heavy metal analysisone gm of soil and 1 g of rice grain samples were digestedafter adding 15mL of triacid mixture (HNO

3 H2SO4 and

HClO4in a 5 1 1 ratio) with three replicates at 80∘C until

a transparent solution was obtained [33] After cooling thedigested sample was diluted up to 30mL with 2 HNO

3

and concentrations of Pb Cd Cu Cr Mn and Zn weredetermined by AAS (GBC makemdashModel Avanta PM)

For plant samples 1 g of dried sample was digested withHNO

3and HClO

4in a 5 1 ratio until a transparent solution

was obtained and the plant digests were filtered and dilutedto 30mL with distilled water (Reddy et al) [32] The filtratesof plant were then assessed by using atomic absorptionspectroscopy (AAS GBC makemdashModel Avanta PM) foranalysis of Pb Cd Cu Cr Mn and Zn The AAS value ofblank (without sample) of each metal was deducted from thesample value for final calculations [26] All the analyses weredone with three replications

23 Bioaccumulation Factor (BAF) The BAF (bioaccumula-tion factor the ratio of the concentration of the element inthe grain to that in the corresponding soil) was calculated for


N

(Km)0 05 1 2


S1

S2

S3

S4

S5

Control

Bay of Bengal

Odiyur lake

Rivulet

80∘02998400E

80∘02998400E 80∘04998400E

80∘04998400E

12∘22

998400N

12∘20

998400N

12∘22

998400N

12∘20

998400N



BAF = CrCs (1)



TF

=


(2)



(3)



(4)




HI =119899

sum

119894=1

HRI (5)
































05

04

03

02

01

00

Bioa

ccum

ulat

ion

fact

or


PbCdCu

CrMnZn










250

200

150

100

50

0

Enric

hmen

t fac

tor


PbCdCu

CrMnZn







(a)


(b)




Adults

Pb 350 402 0269

1561Cd 100 027 0042Cu 4000 166 0001Cr 150000 198 0123Zn 30000 3704 1126

Children

Pb 350 350 0234

1360Cd 100 023 0036Cu 4000 145 0001Cr 150000 173 0108Zn 30000 3228 0981



4 Conclusion







Acknowledgments


References



















































































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of


N

(Km)0 05 1 2


S1

S2

S3

S4

S5

Control

Bay of Bengal

Odiyur lake

Rivulet

80∘02998400E

80∘02998400E 80∘04998400E

80∘04998400E

12∘22

998400N

12∘20

998400N

12∘22

998400N

12∘20

998400N



BAF = CrCs (1)



TF

=


(2)



(3)



(4)




HI =119899

sum

119894=1

HRI (5)
































05

04

03

02

01

00

Bioa

ccum

ulat

ion

fact

or


PbCdCu

CrMnZn










250

200

150

100

50

0

Enric

hmen

t fac

tor


PbCdCu

CrMnZn







(a)


(b)




Adults

Pb 350 402 0269

1561Cd 100 027 0042Cu 4000 166 0001Cr 150000 198 0123Zn 30000 3704 1126

Children

Pb 350 350 0234

1360Cd 100 023 0036Cu 4000 145 0001Cr 150000 173 0108Zn 30000 3228 0981



4 Conclusion







Acknowledgments


References



















































































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of



HI =119899

sum

119894=1

HRI (5)
































05

04

03

02

01

00

Bioa

ccum

ulat

ion

fact

or


PbCdCu

CrMnZn










250

200

150

100

50

0

Enric

hmen

t fac

tor


PbCdCu

CrMnZn







(a)


(b)




Adults

Pb 350 402 0269

1561Cd 100 027 0042Cu 4000 166 0001Cr 150000 198 0123Zn 30000 3704 1126

Children

Pb 350 350 0234

1360Cd 100 023 0036Cu 4000 145 0001Cr 150000 173 0108Zn 30000 3228 0981



4 Conclusion







Acknowledgments


References



















































































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of
























05

04

03

02

01

00

Bioa

ccum

ulat

ion

fact

or


PbCdCu

CrMnZn










250

200

150

100

50

0

Enric

hmen

t fac

tor


PbCdCu

CrMnZn







(a)


(b)




Adults

Pb 350 402 0269

1561Cd 100 027 0042Cu 4000 166 0001Cr 150000 198 0123Zn 30000 3704 1126

Children

Pb 350 350 0234

1360Cd 100 023 0036Cu 4000 145 0001Cr 150000 173 0108Zn 30000 3228 0981



4 Conclusion







Acknowledgments


References



















































































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of





05

04

03

02

01

00

Bioa

ccum

ulat

ion

fact

or


PbCdCu

CrMnZn










250

200

150

100

50

0

Enric

hmen

t fac

tor


PbCdCu

CrMnZn







(a)


(b)




Adults

Pb 350 402 0269

1561Cd 100 027 0042Cu 4000 166 0001Cr 150000 198 0123Zn 30000 3704 1126

Children

Pb 350 350 0234

1360Cd 100 023 0036Cu 4000 145 0001Cr 150000 173 0108Zn 30000 3228 0981



4 Conclusion







Acknowledgments


References



















































































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of






250

200

150

100

50

0

Enric

hmen

t fac

tor


PbCdCu

CrMnZn







(a)


(b)




Adults

Pb 350 402 0269

1561Cd 100 027 0042Cu 4000 166 0001Cr 150000 198 0123Zn 30000 3704 1126

Children

Pb 350 350 0234

1360Cd 100 023 0036Cu 4000 145 0001Cr 150000 173 0108Zn 30000 3228 0981



4 Conclusion







Acknowledgments


References



















































































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of



(a)


(b)




Adults

Pb 350 402 0269

1561Cd 100 027 0042Cu 4000 166 0001Cr 150000 198 0123Zn 30000 3704 1126

Children

Pb 350 350 0234

1360Cd 100 023 0036Cu 4000 145 0001Cr 150000 173 0108Zn 30000 3228 0981



4 Conclusion







Acknowledgments


References



















































































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of





Acknowledgments


References



















































































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of























































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of



















Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of





Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of

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