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Journal of Hazardous Materials 262 (2013) 1056– 1063

Contents lists available at ScienceDirect

Journal of Hazardous Materials

j o ur nal homep age: www.elsev ier .com/ locate / jhazmat

onsumption of arsenic and other elements from vegetables and drinking waterrom an arsenic-contaminated area of Bangladesh

ohammad Mahmudur Rahmana,b, Md. Asaduzzamana,b, Ravi Naidua,b,∗

Centre for Environmental Risk Assessment and Remediation (CERAR), University of South Australia, Mawson Lakes Campus, Mawson Lakes, South Australia, SA 5095, AustraliaCooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC-CARE), P.O. Box 486, Salisbury South, SA 5106, Australia

i g h l i g h t s

Concentrations of As and other elements in vegetables and drinking water.Concentrations of As and other elements in garden soils.Daily dietary intake of As and other elements for adults from vegetables and water.Potential health risk was estimated comparing with the FAO/WHO values of metals.Vegetables alone contribute the elemental intake below the PMTDI values.

r t i c l e i n f o

rticle history:eceived 22 December 2011eceived in revised form 17 June 2012ccepted 25 June 2012vailable online 30 June 2012

eywords:rsenic

a b s t r a c t

The study assesses the daily consumption by adults of arsenic (As) and other elements in drinking waterand home-grown vegetables in a severely As-contaminated area of Bangladesh. Most of the examinedelements in drinking water were below the World Health Organization (WHO) guideline values exceptAs. The median concentrations of As, cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), lead (Pb),Mn, nickel (Ni), and zinc (Zn) in vegetables were 90 �g kg−1, 111 �g kg−1, 0.80 mg kg−1, 168 �g kg−1,13 mg kg−1, 2.1 mg kg−1, 65 mg kg−1, 1.7 mg kg−1, and 50 mg kg−1, respectively. Daily intakes of As, Cd,Cr, Co, Cu, Pb, manganese (Mn), Ni, and Zn from vegetables and drinking water for adults were 839 �g,

roundwaterarden soilegetablesealth risk

2.9 �g, 20.8 �g, 5.5 �g, 0.35 mg, 56.4 �g, 2.0 mg, 49.1 �g, and 1.3 mg, respectively. The health risks fromconsuming vegetables were estimated by comparing these figures with the WHO/FAO provisional toler-able weekly or daily intake (PTWI or PTDI). Vegetables alone contribute 0.05 �g of As and 0.008 mg of Cuper kg of body weight (bw) daily; 0.42 �g of Cd, 8.77 mg of Pb, and 0.03 mg of Zn per kg bw weekly. Otherfood sources and particularly dietary staple rice need to be evaluated to determine the exact health risksfrom such foods.

. Introduction

Geogenic As contamination of groundwater has been reportedn various regions worldwide, particularly in south-east Asia.ountries such as Bangladesh, India (in several states), Nepal,yanmar, Pakistan, Vietnam, Lao People’s Democratic Republic

PDR), Cambodia, China (in several provinces), and the lowlands

f Sumatra in Indonesia are contaminated with As in groundwa-er [1]. Bangladesh and the state of West Bengal in India are thewo worst As-contaminated areas, where more than 100 million

∗ Corresponding author at: Centre for Environmental Risk Assessment and Reme-iation (CERAR), University of South Australia, Mawson Lakes Campus, Mawsonakes, South Australia, SA 5095, Australia. Tel.: +61 8 8302 5041;ax: +61 8 8302 3057.

E-mail address: ravi.naidu@crccare.com (R. Naidu).

304-3894/$ – see front matter © 2012 Elsevier B.V. All rights reserved.ttp://dx.doi.org/10.1016/j.jhazmat.2012.06.045

© 2012 Elsevier B.V. All rights reserved.

people are potentially at risk from groundwater As contamination[1]. The British Geological Survey (BGS) estimated that 35 millionpeople are exposed to As levels above 50 �g L−1 while 57 millionare exposed to As levels above 10 �g L−1. These figures are basedon the BGS analysis of 3534 tubewells in 61 of the 64 districts ofBangladesh alone [2].

Besides As, concentrations of other elements such as Mn, Cr,Pb, Ni, and U also exceeded the World Health Organization (WHO)health-based drinking water guideline values in the groundwa-ter of Western Bangladesh [3]. The accumulation of As in foodcrops – especially rice and vegetables grown in areas of Bangladeshirrigated with As-contaminated groundwater – is now well docu-mented [4–12]. While a number of studies focused on total and

speciated As in Bangladeshi rice and vegetables [4–12], to datestudies on other elements present in vegetables are very limited[4,11]. The concentrations of Cu, Zn, Cd, and Pb were reported in aseverely As-contaminated village (Samta) of Bangladesh [4]. Some

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egetables such as bottle ground leaf (lau shak), ghotkol, taro (kachurati), eddoe (Mukhi kachu) and elephant foot (ol kachu) had muchigher concentrations of Pb compared to Cd, and other leafy andoot vegetables contained higher concentrations of Zn and Cu [4].t is therefore important to determine: firstly, the content of Asnd other elements in home-grown vegetables in As-contaminatedreas of Bangladesh; and secondly, the associated risks from con-uming contaminated vegetables.

Chronic As exposure from drinking contaminated water causeskin manifestations such as pigmentation, where depigmenta-ion affects the trunk and limbs while keratosis affects the handsnd feet [13]. Exposure to As has also been associated withn increased risk of diabetes mellitus, peripheral neuropathy,epatomegaly, peripheral vascular disease, cardiovascular effects,regnancy problems, cerebrovascular disease, non-pitting oedemaf hands, feet, or legs, and cancer of the lungs, kidney, bladder,nd skin [13]. Copper is an essential nutrient for human healthut it is also a drinking water pollutant; food and water are thewo major sources of Cu exposure in developed countries [14].ong-term exposure to elevated levels of Cu can cause irritationf the nose, mouth, and eyes as well as headaches, stomach aches,izziness, and acute gastrointestinal effects such as vomiting andiarrhoea [15]. Long-term exposure to Cu levels above 1000 �g L−1

n drinking water has been found to cause kidney and liver damagen infants [16].

Inhaled Ni compounds are carcinogenic to humans althoughhere is a lack of evidence of a carcinogenic risk from oral exposureo Ni [14]. Food is the main source of Ni exposure in the non-moking, non-occupationally exposed population [14]. Manganeses an essential nutrient and excessive exposure to Mn has been asso-iated with adverse health effects including neurotoxicity [17]. Aelationship was observed between Mn in water and child intellec-ual function in the absence of estimates for levels of food and airn Araihazar, located in Bangladesh [17]. Food is the main sourcef daily exposure to Cd, an element which causes increased riskf tubular dysfunction when exposure occurs at the current PTWI14]. Lead in drinking water can cause a variety of health problems.

prolonged period of Pb exposure causes kidney issues or highlood pressure in adults and delays in physical and mental devel-pment in children [18]. Zinc is essential for all living organisms3].

Drinking water, pond water used to irrigate home gardens, gar-en soils, and various types of home-garden vegetables (leafy andon-leafy) were sampled from Noakhali to assess the concentra-ions of As and other elements such as Cr, Mn, Ni, Co, Cu, Zn, Cd,nd Pb. Noakhali is one of the most highly As-contaminated districtsn Bangladesh; 99% and 95% of 843 hand tubewell water samplesad As levels above 10 �g L−1 and 50 �g L−1, respectively [19]. Weecently reported the level of As in drinking water, cooking waternd rice from the same area and the daily consumption of total andnorganic As from those sources [20]. The main objectives of thistudy were to determine the quantity of As and other elementsngested from vegetables and drinking water by adult membersf the families surveyed in two villages of the Noakhali district ofangladesh.

. Materials and methods

.1. Sample collection and preparation

Drinking water (n = 14), garden top soils (n = 17), and a total of 87

ome-garden leafy (n = 62) and non-leafy (n = 25) vegetables whichere commonly consumed collected from 14 households in two

djacent villages (Chiladi and Basantapur) situated in the Noakhaliistrict in Bangladesh during December 2008. Due to the mitigation

s Materials 262 (2013) 1056– 1063 1057

activities, all surveyed families were aware of As contamination ingroundwater and revealed that pond water was currently used toirrigate their garden vegetables. We also collected and analysedwater from 14 ponds used by the selected households for agricul-tural irrigation of their home gardens. During the field sampling,interviews were undertaken with all surveyed families to establishthe rate of daily intake of vegetables and water by each individual.A few samples of cooked vegetables (n = 5) were also collected. Allfood samples except cooked vegetables were washed three timeswith tap water followed by de-ionized water (twice). Vegetableswere dried in an oven at 65 ◦C and homogenized by grinding themwith a stainless steel grinder. Concentrated nitric acid was used forthe digestion of vegetables; this digestion procedure was reportedelsewhere [21]. Elemental concentrations in vegetables were deter-mined on a dry weight basis. A microwave digestion system (model:MARS 5, CEM) was used for the digestion of soil using the USEPA3051 method.

2.2. Sample analysis

An Agilent 7500c (Agilent Technologies, Tokyo, Japan) induc-tively coupled plasma mass spectrometer (ICP-MS) was used todetermine the amount of As and other elements in vegetables,water, and soil.

2.3. Analysis of standard reference materials (SRMs)

Standard reference materials (SRMs) from the National Instituteof Standards and Technology (NIST) such as 1640 (trace elementsin natural water), 2711 (Montana soil), and 1573a (tomato leaves)were used to verify the results for As and other elements in water,soil, and vegetables, respectively. Montana soil and tomato leaveswere digested after utilizing the same procedure as that used forsoil and vegetable samples. The analytical results of As and othermetals in trace elements in natural water, Montana soil, and tomatoleaves indicate that the observed values are very close to the certi-fied values (Tables 1–3).

2.4. Consumption of As and other elements by adults

The daily consumption of As and other elements from vegetablesand drinking water by adults in this study is calculated by using thefollowing equation:

DCE = CRV × CEV + CRD × CED

where DCE, daily consumption of elements; CRV, median consump-tion rate of vegetables; CEV, median concentrations of elementsobserved in vegetables; CRD, median consumption rate of drink-ing water; CED, median concentrations of elements observed indrinking water.

3. Results and discussion

3.1. Contents of As and other elements in drinking water

Table 1 summarises the results for the analysis of As and otherelements present in drinking water. It appears that all drinkingwater samples exceeded the recommended level of As for drinkingwater set by the WHO (10 �g L−1). The average As concentration intubewell water samples was almost 33 times greater than the WHOrecommended level. Only one sample was below the Bangladesh

standard for As (50 �g L−1). With the exception of As, the levels ofother elements were below the WHO guideline values. Currentlythere is no WHO guideline value for Mn in drinking water [22],only one sample exceeded the previous WHO guideline value for

1058 M.M. Rahman et al. / Journal of Hazardous Materials 262 (2013) 1056– 1063

Table 1Concentrations of As and other elements in groundwater used for drinking and pond water used for agricultural irrigation of home gardens collected from Noakhali districtof Bangladesh.

Parameter Drinking water (n = 14) NIST SRM water 1640 Pond water (n = 14)

Mean(�g L−1)

Median(�g L−1)

Range(�g L−1)

WHO’s guidelinevalues (�g L−1)

No. of samplesexceeding WHOguideline value (%)

Certified values Observedvalues (n = 3)

Mean(�g L−1)

As 328 279 14–772 10 14 (100) 26.67 ± 0.41 26.31 ± 0.28 2.5Cd <0.05 <0.05 – 3 – 22.79 ± 0.96 21.85 ± 0.67 <0.05Co 0.57 0.36 0.16–1.31 – – 20.28 ± 0.31 19.62 ± 0.19 0.4Cr 0.81 0.62 0.26–3.17 50 – 38.6 ± 1.6 35.4 ± 0.7 0.8Cu 4.64 2.33 0.34–19.37 2000 – 85.2 ± 1.2a 86.2 ± 0.8 0.9Mn 192 112 21–459 – – 121.5 ± 1.1 114.5 ± 1.1 153Ni 1.24 1.03 0.68–2.57 70 – 27.4 ± 0.8a 26.02 ± 0.3 1.8Pb 0.17 0.15 0.10–0.38 10 – 27.89 ± 0.14 26.97 ± 0.10 0.8Zn 23.23 7.71 0.13–89.85 – – 53.2 ± 1.1a 49.9 ± 1.1 3.9

a Reference values.

Table 2Concentrations of As and other elements (�g g−1) in home garden soils (n = 17) collected from Noakhali district of Bangladesh.

Parameter As Cd Co Cr Cu Mn Ni Pb Zn

Mean 3.3 0.07 10 29 22 303 64 13 75Median 2.9 0.05 10 27 21 305 63 12 71Range 1.5–9.2 0.03–0.2 6–14 18–46 13–63 192–496 37–93 8–22 50–116Montana soil Certified/non-certified values

105 ± 8 41.7 ± 0.25 10a 47a 114 ± 2 638 ± 28 20.6 ± 1.1 1162 ± 31 350.4 ± 4.8

Montana soil observed values 99 ± 4 42.1 ± 0.30 8 ± 3 41.3 ± 2.8 99 ± 2 589 ± 36 19.1 ± 2.3 1170 ± 32 335.1 ± 4.9

a Non-certified values.

Table 3Concentrations of As and other elements in all vegetables.

Elements Mean Median Range NIST SRM 1573a

Certified values Observed values

As (�g kg−1) 113 90 11–464 112 ± 0.004 119 ± 3Cd (�g kg−1) 134 111 6–428 1520 ± 40 1460 ± 60Co (�g kg−1) 216 168 16–974 570 ± 20 610 ± 40Cr (mg kg−1) 0.98 0.80 0.18–4.48 1.99 ± 0.06 1.85 ± 0.08Cu (mg kg−1) 18 13 2–86 4.70 ± 0.14 5.01 ± 0.19Mn (mg kg−1) 124 65 4–881 246 ± 8 235 ± 6

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study was much lower compared to what previous studies havereported from Bangladesh and West Bengal because As-safe pondwater was used to irrigate home-grown vegetables at the time ofthis study. Fig. 1 presents a bar diagram of mean concentrations

Ni (mg kg ) 2.1 1.78

Pb (mg kg−1) 3.1 2.18

Zn (mg kg−1) 55 50

n (400 �g L−1); this sample’s value was 459 �g L−1. Thus out of4 samples only one was detected where levels of As and Mn werebove 10 �g L−1 and above 400 �g L−1, although the total sampleize was low. Consequently the drinking water sources of the other3 families were found to be safe with respect to other elementsuch as Cr, Mn, Ni, Co, Cu, Zn, Cd, and Pb.

.2. Contents of As and other elements in pond water

The mean concentrations of As and other elements in pondater used for the irrigation of home-garden vegetables were found

o be safe according to the WHO recommended levels (Table 1).

.3. Contents of As and other elements in garden soils

The concentrations (mean, median, and range) of As and otherlements in soils are presented in Table 2. Arsenic levels in 71addy soils (depth 0–15 cm) varied from 3.1 and 42.5 �g g−1 (aver-ge: 15.2 �g g−1 and median: 12.8 �g g−1) in a study reported fromangladesh [23]. Another study found that As levels in 25 soils

depth 0–15 cm) ranged from an undetectable level to 31.8 �g g−1

average: 11.9 �g g−1 and median: 8.9 �g g−1) [24]. These inves-igators also reported that As content in soils was positivelyorrelated with As content in irrigation water [24]. The mean

.32–5.68 1.59 ± 0.07 1.68 ± 0.08

.67–16.5 – 1.46 ± 0.0617–183 30.9 ± 0.7 32.2 ± 0.9

and median As concentrations of agricultural lands in West Ben-gal, India, were 10.7 mg kg−1 and 7.3 mg kg−1, with a range of3.3–31.6 mg kg−1 [25]. The mean and median As content in this

Fig. 1. Bar diagram of mean concentrations of As and other elements in soils com-pared with the data reported from As-affected areas of Bangladesh and West Bengal.

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f As and other elements in soils compared to the data reportedn previous studies from As-affected areas of Bangladesh and Westengal. The mean concentrations of Cr, Cu, Mn and Pb in the exam-

ned soils were comparable with the results of the study conductedn West Bengal [25]. Levels of most of the elements in this studyxcept Cd and Ni were much lower in the examined soils comparedo the study conducted in Faridpur district of Bangladesh [26].

.4. Daily consumption of vegetables

The daily vegetable consumption rate for adult males andemales (n = 71, age range 12–80 years) was an average of 205 gmedian: 200 g, fresh weight), which is equivalent to 26 g (dryeight), considering there was on average 87% moisture content

n the vegetables. The vegetable intake rate is much higher thann the village of Samta, where the average per capita consump-ion of leafy and non-leafy vegetables is 130 g per person dailyor adults of all ages [4]. The vegetable intake varied from 126o 169 g daily amongst Bangladeshi adults according to a recenttudy in Bangladesh [27]. The villagers in this study area areocio-economically rich and this could be one reason why veg-table intake was higher compared to other studies conducted inangladesh. The median intake of drinking water among adults was

L per day.

.5. Contents of As and other elements in different types ofome-grown vegetables and compared to other studies

The mean, median, and range of As and other elements in allegetables are presented in Table 3. Figs. 2–4 show concentrationsf Co, As, Cd, Cr, Ni, Pb, Mn, Cu, and Zn in different types of gardenegetables.

.5.1. ArsenicThe vegetables with the highest mean As levels were

rum leaf > pumpkin leaf > coriander leaf > radish leaf > gourdeaf > radish > spinach > red amaranth > arum stem > Indianpinach > arum tuber > bean > papaya > green chilli > eggplant.ndividual vegetable gourd leaves showed the highest As con-entration whereas bean exhibited the lowest As content. Theange of As levels in home-grown vegetables from Samta villagen Bangladesh was 19–489 �g kg−1 [4]. The range of As levels

as 70–3990 �g kg−1 in vegetables from Chandpur and Jamalpuristricts [6] and <40–1930 �g kg−1 in vegetables from Sathkhira,ajshahi, and Comilla districts [7]. The range of As levels in thistudy was comparable with the results from Samta [4] but muchower than in another two studies [6,7]. In a recent study, theange of As levels in 45 vegetable samples collected from Matlab ofangladesh was 0.5–26 �g kg−1 [12]. A study assessed As and othereavy metals in vegetables from Jalangi and Domkal blocks ofest Bengal in India and reported that the mean As levels in veg-

tables were 20.9 �g kg−1 (<0.04–138 �g kg−1) and 21.2 �g kg−1

0.04–212 �g kg−1) in Jalangi and Domkal, respectively [28].oth studies [12,28] found very low mean As concentrations inegetables compared to other studies undertaken in Bangladeshnd West Bengal.

In the case of leafy vegetables, the mean and median As con-entrations were 141 �g kg−1 and 110 �g kg−1, respectively (range:1–464 �g kg−1). The range of As levels in leafy vegetables fromathkhira, Rajshahi, and Comilla districts was 100–790 �g kg−1

7]. On the other hand, the mean and median As concentrationsf non-leafy vegetables were 45 �g kg−1 and 30 �g kg−1 (range:

1–145 �g kg−1). The range of As levels in non-leafy vegetablesfruit, root, and tuber) from Sathkhira, Rajshahi, and Comilla dis-ricts was <40–1930 �g kg−1 [7]. Arsenic levels were much lowern both leafy and non-leafy vegetables in our study compared to

s Materials 262 (2013) 1056– 1063 1059

the previous study [7]. The uptake of metals in vegetables from soilvaries from area to area depending on the concentrations of metalsin soils and irrigation water.

The mean and median As concentrations detected in cookedvegetables were 356 �g kg−1 and 288 �g kg−1, respectively, witha range of 98–754 �g kg−1. Based on 39 cooked vegetable samplesfrom Munshiganj and Monohordi of Bangladesh, the reported meanand range of As were 333 �g kg−1 and 19–2334 �g kg−1, respec-tively [8]. Although the mean As concentration in cooked vegetablesof this study is comparable to that found in a previous study [8],the maximum level of As was much lower. This is because all thefamilies in this study used As-safe pond water for cooking [20].

3.5.2. CadmiumThe vegetables with the highest mean Cd levels were

spinach > coriander leaf > radish leaf > Indian spinach > red ama-ranth. The Cd concentrations in all vegetables in Samta villagevaried between 12 �g kg−1 and 216 �g kg−1 [4]. The mean Cd con-centration of vegetables from Matlab in Bangladesh was 27 �g kg−1

[12], which was much lower than that found in our study. Pre-vious study shows that the mean Cd levels in amaranth, bittergourd, and eggplant were 33 �g kg−1, 21.1 �g kg−1, and 27 �g kg−1,respectively [12]. In our study, the mean concentration of eggplantwas almost 2.8 times higher than that found in a previous studyfrom Bangladesh [12]. The mean and median Cd concentrations ofleafy vegetables were 163 �g kg−1 and 144 �g kg−1, respectively(range: 16–428 �g kg−1). The mean and median Cd concentrationsof non-leafy vegetables were 58 �g kg−1 and 24 �g kg−1 (range:6–265 �g kg−1). The mean and median Cd concentrations in cookedvegetables were 147 �g kg−1 and 183 �g kg−1, respectively, rang-ing from 42–211 �g kg−1. The mean concentrations of Cd in rawand cooked vegetables are almost the same.

3.5.3. ChromiumThe vegetables with the highest mean Cr levels were coriander

leaf > radish leaf > red amaranth > pumpkin leaf > spinach > arumleaf > gourd leaf. The mean and median Cr concentrations inleafy vegetables were 1.12 mg kg−1 and 0.89 mg kg−1, respectively(range: 0.35–4.48 mg kg−1). The mean and median Cr concentra-tions of non-leafy vegetables were 0.64 mg kg−1 and 0.45 mg kg−1

(range: 0.18–1.91 mg kg−1). The mean Cr concentration in veg-etables of this study was considerably lower than the meanCr concentrations detected in vegetables from five Upazilasin Feni district of Bangladesh [Dagon Bhuyia (33.84 mg kg−1),Feni Sadar (27.37 mg kg−1), Sonagazi (25.89 mg kg−1), Pulgazi(25.28 mg kg−1), and Parsuram (23.31 mg kg−1)] [11]. The mean andmedian Cr concentrations in cooked vegetables were 1.2 mg kg−1

and 1.4 mg kg−1, respectively, with a range of 0.58–1.9 mg kg−1. Themean Cr level in cooked vegetables was slightly higher than in rawvegetables.

3.5.4. CobaltThe vegetables with the highest mean Co levels

were arum tuber > red amaranth > arum leaf > corianderleaf > spinach > pumpkin > radish leaf. The mean and medianCo concentrations in leafy vegetables were 252 �g kg−1 and228 �g kg−1 respectively (range: 48–644 �g kg−1). The meanand median Co concentrations of non-leafy vegetables were127 �g kg−1 and 58 �g kg−1 (range: 16–974 �g kg−1). Regardingcooked vegetables, the mean and median Co concentrationswere 147 �g kg−1 and 85 �g kg−1, respectively, with a range of63–227 �g kg−1, which is lower than in raw vegetables.

3.5.5. CopperThe vegetables with the highest mean Cu levels were arum

tuber > bean > gourd leaf > arum leaf > Indian spinach > coriander

1060 M.M. Rahman et al. / Journal of Hazardous Materials 262 (2013) 1056– 1063

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Fig. 2. Concentrations o

eaf. The mean and median Cu concentrations in leafy vegeta-les were 17.3 mg kg−1 and 13.7 mg kg−1 respectively (range:.5–84.2 mg kg−1). The mean and median Cu concentrations ofon-leafy vegetables were 20.6 mg kg−1 and 11.9 mg kg−1 (range:.1–86.3 mg kg−1). The average Cu concentrations in leafy andon-leafy vegetables from Samta were 15.5 and 8.51 mg kg−1,espectively [4]. The mean Cu level in leafy vegetables ofhis study was comparable to that in Samta but the valueas considerably higher for non-leafy vegetables. The meanu level in all vegetables was significantly higher than theest Bengal study [28], where the mean Cu levels in vegeta-

les were 1.59 mg kg−1 (0.032–4.02 mg kg−1) and 1.58 mg kg−1

0.33–4.21 mg kg−1) in Jalangi and Domkal blocks, respectively.

he mean and median Cu concentrations in cooked vegeta-les were 2.9 mg kg−1 and 1.3 mg kg−1, respectively, with aange of 1.1–9.3 mg kg−1, which is much lower than in rawegetables.

Fig. 3. Concentrations of Cr, N

s, and Cd in vegetables.

3.5.6. LeadThe vegetables with the highest mean Pb levels were

bean > papaya > arum tuber > arum leaf > coriander leaf. The rangeof Pb levels in all vegetables (Table 3) was appreciably higher thanin Samta, where the range of Pb concentrations in all vegetables was0.143–1.689 mg kg−1 [4]. The mean and median Pb concentrationsin leafy vegetables were 2.8 mg kg−1 and 2.2 mg kg−1 respectively(range: 0.85–13.8 mg kg−1). The mean and median Pb concentra-tions of non-leafy vegetables were 3.7 mg kg−1 and 1.9 mg kg−1,respectively (range: 0.67–16.5 mg kg−1). The mean and medianPb concentrations in cooked vegetables were 6.9 mg kg−1 and3.0 mg kg−1, respectively, with a range of 1.1–9.3 mg kg−1, whichis almost three times higher than in raw vegetables.

3.5.7. ManganeseThe vegetables with the highest mean Mn levels were arum

leaf > pumpkin leaf > gourd leaf > spinach > arum stem > red ama-

i, and Pb in vegetables.

M.M. Rahman et al. / Journal of Hazardous Materials 262 (2013) 1056– 1063 1061

Mn, C

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anth. The mean concentration of Mn in all vegetables was substan-ially higher than in Jalangi and Domkal, where the mean Mn levelsn vegetables were 3.3 mg kg−1 (0.7–9.49 mg kg−1) and 4.2 mg kg−1

0.22–15.4 mg kg−1), respectively [28]. The mean and mediann concentrations in leafy vegetables were 160.3 mg kg−1and

1.1 mg kg−1, respectively (range: 33.7–881.3 mg kg−1). For non-eafy vegetables, the mean and median Mn concentrations were4.5 mg kg−1 and 27.4 mg kg−1 (range: 4.0–176.8 mg kg−1). Theean and median Mn concentrations in cooked vegetables were

6.1 mg kg−1 and 17.2 mg kg−1, respectively, with a range of3.4–113.1 mg kg−1, which is much lower than in raw vegetables.

.5.8. NickelThe vegetables with the highest mean Ni levels were

oriander leaf > red amaranth > pumpkin leaf > radish leaf > arumeaf > spinach. The mean concentration of Ni in all vegetables

as noticeably higher than that reported in the previous studyrom West Bengal [28], where the mean Ni levels in vegeta-les were 0.36 mg kg−1 (<0.0002–1.04 mg kg−1) and 0.16 mg kg−1

<0.0002–0.53 mg kg−1) in Jalangi and Domkal, respectively.he mean and median Ni concentrations in leafy vegeta-les were 2.47 mg kg−1 and 2.26 mg kg−1, respectively (range:.817–5.684 mg kg−1). The mean and median Ni concentrations

n non-leafy vegetables were 1.439 mg kg−1 and 1.264 mg kg−1

range: 0.321–4.696 mg kg−1). The mean and median Ni concen-rations in cooked vegetables were 1.9 mg kg−1 and 1.3 mg kg−1,espectively, with a range of 1.01–3.6 mg kg−1, which is slightlyower than in raw vegetables.

.5.9. ZincThe vegetables with the highest mean Zn levels were red ama-

anth > arum tuber > pumpkin leaf > spinach > coriander leaf > arumtem. The average Zn level among all categories of vegetablesas found to be 95.6 mg kg−1 (range: 7–304 mg kg−1) [11], whichas greatly higher than in this study. The mean Zn levels in

egetables were 5.33 mg kg−1 (2.01–9.52 mg kg−1) and 5 mg kg−1

0.84–12.8 mg kg−1) in Jalangi and Domkal, respectively [28],

hich was much lower than in this study. In leafy vegetables,

he mean and median Zn concentrations were 59.6 mg kg−1 and2.2 mg kg−1, respectively (range: 21.4–182.9 mg kg−1), while theean and median Zn concentrations of non-leafy vegetables

u, and Zn in vegetables.

were 44.3 mg kg−1 and 42.7 mg kg−1 (range: 17.2–122.3 mg kg−1).The mean and median Zn concentrations in cooked vegetableswere 38.8 mg kg− and 38.9 mg kg−1, respectively, with a range of24.5–54.1 mg kg−1, which is lower than in raw vegetables.

The Pearson product-moment correlation co-efficient was usedto discover whether there is any correlation between As andany other elements. A strong positive correlation (r = 0.74) wasobserved between As and Mn in vegetables. The concentrationsof As, Cr, and Pb were higher in raw vegetables compared to thecooked vegetables and Co, Cu, Mn, Ni, and Zn concentrations werehigher in cooked vegetables than in raw vegetables. Cooking watermay play an important role in this variation. Although two studies[4,28] were conducted in severely As-affected areas (Samta, Jalangi,and Domkal) of Bangladesh and West Bengal, respectively, the lev-els of other metals in vegetables were comparatively lower thanthose observed in this study.

3.5.10. Consumption of As and other elements from vegetablesand drinking water

The daily total consumption of As and other elements from veg-etables and drinking water for adults is presented in Table 4. Theestimated daily average intake of total As from leafy and non-leafyvegetables of Samta was 27.8 �g day−1 [4]. Daily As intake fromvegetables was much lower in this study compared to the pre-vious study [11] where the average estimated As intake of Feni,Bangladesh, was 105 �g day−1. The estimated average daily dietaryintakes of As from vegetables by adults were 10.4 �g and 10.6 �gin the Jalangi and Domkal blocks, respectively [28]. The daily Asconsumption from vegetables in this study was much lower thanSamta and Jalangi and Domkal blocks. Calculated daily median Asintake from drinking water by adults was 837 �g. Adults consume839 �g of As from both drinking water and vegetables. Thus drink-ing water contributes considerable As to the daily exposure. Thedaily As contribution from rice, vegetables and drinking water ispresented in Fig. 5.

In a recent evaluation conducted by the Joint FAO/WHO ExpertCommittee on Food Additives (JECFA), the PTDI of As (2.1 �g kg−1

bw) has been withdrawn and is no longer valid as the inorganicAs lower limit of the benchmark dose for a 0.5% increased theincidence of lung cancer (BMDL0.5). This was determined fromepidemiological studies to be 3.0 �g kg−1 bw per day (2–7 �g kg−1

1062 M.M. Rahman et al. / Journal of Hazardous Materials 262 (2013) 1056– 1063

Table 4Daily intake of As and other elements from vegetables and drinking water.

Elements Median intake ofvegetables (g) perday for adults

Medianconcentration invegetables (�g kg−1)

Intake fromvegetables (�gor mg)

Median intakeof water (L) perday for adults

Median concentrationin drinking water(�g L−1)

Intake fromdrinking water(�g)

Total intake fromvegetables and water(�g or mg)

As 90 2.3 279 837 839.3Cd 111 2.9 – – 2.9Co 168 4.4 0.36 1.1 5.5Cr 800 20.8 0.62 1.9 22.7Cu 26 13a 0.34b 3 2.33 7.0 0.35b

Mn 65a 1.7b 112 336 2.0b

Ni 1700 46 1.03 3.1 49.1Pb 2100 56 0.15 0.4 56.4Zn 50a 1.3b 7.71 23.1 1.3b

butaBbodf

pTBkmwtdb

wip3ihclbt

Fa

a Units expressed in mg kg−1.b Units expressed in mg.

w per day based on the range of estimated total dietary exposure)sing a range of assumptions to estimate total dietary exposureo inorganic As from drinking water and food [29]. Based on theverage bw of a Bangladeshi adult (45 kg) from Madaripur thana ofangladesh [30], vegetables alone contribute 0.05 �g of As per kgw daily. Both vegetables and drinking water contribute 18.6 �gf As per kg bw daily. The value would be 20 �g of As per kg bwaily, when we combine As contribution from rice (data derivedrom [20]), vegetables and drinking water.

The Cu intake from vegetables in this study was half that of therevious study done in West Bengal [4]. The Provisional Maximumolerable Daily Intake (PMTDI) of Cu is 0.05–0.5 mg kg−1 bw [31].oth vegetables and drinking water contribute 0.008 mg of Cu perg bw daily, which is much lower than the PMTDI value. The esti-ated average daily dietary intakes of Ni from vegetables for adultsere 180 �g and 80 �g in the Jalangi and Domkal blocks, respec-

ively [28]. In this study, the Ni intake from both vegetables andrinking water was much lower than both in Jalangi and Domkallocks.

The calculated Mn intake from vegetables for adults in this studyas comparable with the Jalangi and Domkal study [28]. The daily

ntake of Mn from vegetables was almost half in this study com-ared to a study undertaken in Bangladesh, where the value was.53 mg [11]. The PTWI of Cd is 7 �g kg−1 bw [32]. The average daily

ntake of Cd from vegetables in Samta village (9.45 �g) was muchigher than that observed in our study (2.9 �g). Thus, vegetablesontribute only 0.06 �g of Cd per kg bw per day, which is equiva-ent to 0.42 �g weekly. As the Cd level in drinking water could not

e detected in this study, drinking water does not add further Cdo the daily exposure.

ig. 5. Daily As (�g) contribution from rice [20], vegetables and drinking water fordults.

The PTWI of Pb is 0.025 mg kg−1 bw [33]. The median daily intakeof Pb from vegetables was much lower than in Samta, where thevalue was 0.523 mg per week. Thus, vegetables contribute only1.25 �g of Pb per kg bw per day, which is equivalent to 8.77 �gper kg bw per week. So, vegetables alone contribute one-third ofthe recommended PTWI of Pb in this study. Drinking water doesnot add further Pb to the daily exposure as the Pb level in drinkingwater was very low. The PMTDI of Zn is 0.3–1 mg kg−1 bw [34]. Theestimated daily intake of Zn in this study was much lower than thatfound in another study in Bangladesh where the value was 87 mg[11]. The daily intake was three times lower than in Samta village(3.5 mg) [4]. Zinc intake was lower compared to the Jalangi andDomkal blocks, where the average daily dietary intakes of Zn fromvegetables by adults were 2.6 �g and 2.5 mg, respectively [28]. Itcan be stated that vegetables and drinking water contribute 0.03 mgof Zn per kg bw per day.

4. Conclusions

The concentrations of metals varied extensively among thedifferent types of vegetables. Leafy vegetables contained higherconcentrations of As, Cd, Cr, Mn, Ni, and Zn than non-leafy veg-etables. Vegetables alone contributed an intake of As and otherelements that was below the PMTDI values. The daily intakes ofother elements from other food sources such as rice need to beevaluated to determine the total exposure to other elements fromthe main Bangladeshi foods. Although we collected various typesof commonly consumed vegetables from the study area, they arenot representative of all vegetables consumed by the populationsin other areas of Bangladesh. Food surveys should not be restrictedto As alone; other elements also need to be monitored regularly.

Acknowledgements

The authors thank CERAR, University of South Australia, forlaboratory support. Financial support from CRC-CARE is gratefullyacknowledged. Md. Asaduzzman is grateful to the ATSE CrawfordFund, Australia, for the fellowship during his training at the CERAR.The authors are grateful to Dhaka Community Hospital, Dhaka,Bangladesh for the laboratory support for processing the vegetablesamples.

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