Groundwater Iron Assessment and Consumption ... - Hogrefe eContent

Int. J. Vitam. Nutr. Res., 82 (1), 2012, 5 – 14

5

Original Communication

Groundwater Iron Assessment and Consumption by Women in Rural Northwestern Bangladesh Rebecca D. Merrill1, Abu A. Shamim2, Hasmot Ali2, Nusrat Jahan2, Alain B. Labrique1, Parul Christian1, and Keith P. West, Jr.1 1

Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA 2 The JiVitA Maternal and Child Health Research Project, Gaibandha, Bangladesh Received: July 15, 2010; Accepted: December 12, 2010

Abstract: In Bangladesh, approximately 97 % of the rural population uses groundwater as a drinking source. In many areas of the country this water is known to have elevated levels of iron. The contribution to iron intake that this exposure provides, and the impact on health, are unknown. In the pre- and postmonsoon seasons of 2008, we measured iron content of household tube well water, explored local water collection methods, and estimated iron intake through consumption of groundwater for 276 women of reproductive age in a rural setting in northwestern Bangladesh. Groundwater samples were analyzed for total iron (mg/L), arsenic (category of μg/L), pH, temperature (oC), and oxidation-reduction potential (Eh). Participants drank [mean (SD); 2.7 (0.8) L] of water per day, all of which was collected from domestic tube wells. Total iron concentration in groundwater was high, [median (IQR) 16.3 (6.9, 28.2) mg/L], and variable throughout the area. Using this value, estimated daily iron intake [median (IQR)] was 41.1 (16.0, 71.0) mg from drinking water alone. The amount of water consumed was unrelated to its iron concentration (r = – 0.06; p = 0.33) despite potentially unpleasant organoleptic qualities of high iron content in water. Groundwater contributes substantially to daily iron intake of rural Bangladeshi women and currently represents an under-assessed potential source of dietary iron. Key words: groundwater, iron, tube well, women, Bangladesh

Introduction Iron, the second most abundant metal on Earth, is an essential nutrient required for hemoglobin and myoglobin synthesis, oxygenation of tissues, enzymatic reactions, and host defenses to infection [1]. Despite iron’s ubiquity in the environment and diet, iron deficiency remains the most common single micronutrient deficiency and cause of anemia in the world, especially among women of reproductive age [2, 3]. To combat DOI 10.1024/0300 – 9831/a000089

the high risk for these conditions, the provision of supplemental iron, in tablet form [4, 5] or as a fortificant in food [6], is often attempted [7]. Surprisingly, in some populations with dietary patterns providing insufficient amounts of bioavailable iron, the prevalence of iron deficiency and consequent anemia, while present, is low [8]. One explanation may lie in the exposure to environmental iron sources, such as groundwater. In Bangladesh, groundwater sources have been shown to have iron concentrations as high

Int. J. Vitam. Nutr. Res. 82 (1) © 2012 Hans Huber Publishers, Hogrefe AG, Bern

6

R. D. Merrill et al.: Groundwater Iron Intake by Women in Rural Bangladesh

as 60 mg/L [9]. Because of an assumed low concentration and bioavailability [10, 11], iron in water is typically not investigated in dietary studies of iron status. However, in contrast to these assumptions, some studies have shown the potential nutritional importance of such a source [12, 13]. Additionally, the World Health Organization (WHO) suggests that “minerals in water are subject to most of the same determinants of bioavailability that affect the utilization of those minerals in foods” [14]. While there is no toxic limit for water iron concentration, WHO has established an aesthetic cutoff of 0.3 mg/L [9, 15]. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has proposed a limit of 2.0 mg/L, defined by allotting 10 % of the provisional maximum tolerable daily intake (PMTDI) for iron to consumed water [11]. Although most industrialized countries and major cities (even in resource-poor settings) are able to provide treated potable water that meets these drinking water guidelines [14], at least 17 % of the world’s population lacks access to improved water sources, two-thirds of whom live in Asia [16]. This population consumes untreated surface and groundwater that is often contaminated with bacteria or heavy metals such as arsenic and manganese, and experiences an associated elevated risk of morbidity and mortality [17 – 21]. As nearly all Bangladeshis in rural areas use groundwater for drinking and cooking [22], and the aquifer environment can be rich in natural iron, a large number may be chronically exposed to dissolved iron levels that are well above the defined guidelines. Importantly, when assessing nutritional status and dietary intake, this groundwater may provide a source of iron that is currently underappreciated. The impact of this daily exposure on nutritional health should be assessed. The main objective of this study, conducted among women in rural northwestern Bangladesh, was to quantify daily iron intake through consumed groundwater, estimated by assessing iron concentration in drinking water sources, quantifying daily drinking water intake, and describing water collection and consumption methods and preferences.

Subjects and Methods The population-based study was conducted during two seasons of 2008, May to July (round 1, hot, dry season) and September to November (round 2, late monsoon, pre-harvest season), among 321 women who had participated in a field trial of vitamin A or

beta-carotene supplementation between August 2001 and January 2007 (“JiVitA-1”) [23 – 24]. The study site was located in rural, northwestern Bangladesh within a larger community research project area of approximately 435 square kilometers that is typical of other rural areas of Bangladesh with respect to diet and maternal and child nutritional status indicators [25 – 27, 51]. The study site was originally selected for a sub-study within the original supplementation trial based on its access to rural roads and close distance (~8 km) to study facilities required to support procedures which included biochemical, clinical, and anthropometric assessments. The participants in the sampling frame (n = 464) fulfilled three inclusion criteria from the original substudy (n = 2115): they had 1) contributed a live birth; 2) completed a full panel of sub-study assessments during the first trimester and 3 months postpartum visits, and 3) been confirmed as residents of the same household throughout the sub-study follow-up. Four hundred participants were randomly selected from the sampling frame to be re-visited during an initial eligibility survey during May to June 2008. Women were deemed ineligible for the study if, at the time of the survey, they had out-migrated or were pregnant. The latter exclusion criteria served to minimize potential effects of pregnancy on otherwise usual water collection and consumption patterns [28]. Participants were visited in their homes during both seasonal rounds for interviews and tube well water analysis by locally hired, project-trained female staff.

Interviews At interviews conducted during both rounds, participants were asked about their main drinking water source. Respondents using groundwater were asked to identify the tube well most used for drinking water in the past 7 days and whether the same structure was also their water source during the original trial. A durable plastic band with a unique 5-digit identification number was riveted to each identified tube well. Participants were asked for how long (years) they had been using the current source and, if relevant, why they changed tube wells. Participants completed a 24-hour drinking water consumption recall using the container they used most often to drink their tube well water. The container material and volume (± 10 mL), measured after asking the participant to fill the container to the usual level when drinking water from the tube well, were recorded. Using the identified drinking container as



a counting unit, participants were interviewed about their 24-hour drinking water consumption, aided by 6 meal and between-meal prompts: “with the morning meal,” “between the morning meal and lunch,” “with lunch,” “between lunch and dinner,” “with dinner,” and “after dinner and before the morning meal.” For each reported container (± 0.5 units), participants defined whether the drinking water was consumed within 5 minutes of pumping, between 5 and 30 minutes or one meal time, more than 30 minutes after collection, or after use of any filtering device. This data collection tool was developed based on focus group discussions with local women and results from 6-day drinking water diaries, during which time some women were visited daily to complete the recall by interview. Using the same 6 meal prompts, women were asked to complete a 24-hour semi-quantitative rice consumption recall. Additionally, each round included a 7-day, 42-item food frequency questionnaire. Unique to the round 1 interview, data on pregnancy history since participation in the original trial and current socioeconomic status (SES) was collected. Current anthropometric status, including weight (± 0.1 kg, UNICEF Uniscale, digital, calibrated daily, SECA, Gmbh & Co., Hamburg, Germany), height (± 0.1 cm, JiVitA-produced stadiometer modeled on a Harpenden stadiometer), mid-upper arm circumference (MUAC, ± 0.1 cm, nonstretch, locally manufactured insertion tape, based on the original design of Zerfas [29]), and subscapular and tricipital skinfold thickness (SSF and TSF, ± 0.2 mm, calibrated weekly, Holtain calipers, Holtain Ltd., Dyfed, Wales) was also collected in round 1 following standard procedures [30]. All measurements, except for weight, were repeated in triplicate and the median value was used for analytic purposes. Interviewers were trained and standardized on anthropometric methods before data collection and were routinely observed and checked in the field by a supervisor.

7

the well, each of which has a standard length (filter, 6 or 10 feet; iron pipe, 5 feet; and plastic pipe, 15 feet). During the first assessment for a given tube well, participants were also asked to rate their perceived level of iron in the tube well water using a 4-point scale (“none,” “a little,” “a medium amount,” and “a lot”). Tube well water was analyzed on the spot for temperature [± 0.1 degrees Celsius (oC), digital Portable Thermometer, Model No: ST-9269 A/B/C, Winning Technology Ltd., Hong Kong], pH (± 0.1 pH, calibrated weekly, ADWA AD100 pH Electronic Meter, Adwa Instruments, Belgium), oxidation reduction potential (ORP) (± 1 Eh, calibrated weekly, HI98201 ORP Tester, HANNA Instruments, Woonsocket, Rhode Island), total arsenic (category of μg/L, AsK100 Arsenic Field Test Kit, Wagtech International Ltd., Berkshire, UK), and total iron (± 0.1 mg/L, FerroVer® method, HACH Iron Test Kit, Model IR-18B, previously validated [31]). Before analysis, tube wells were pumped continuously for 5 minutes to purge any residual minerals that may have built up in the pipe and to ensure the aquifer source was reached. Subsequently, pH, temperature, and ORP were measured using a water sample collected directly from the tube well water flow. After collecting a fresh water sample from the tube well, the arsenic and iron tests were conducted. From a random 10 % of tube wells, water samples were collected into trace element-free polyethylene terephthalate (PET) bottles, acid-preserved to pH < 2.0 with HCl to prevent iron precipitation, and stored the same day at –20oC until analysis within one month by atomic absorption spectrophotometry (AAS), an accepted gold standard for assessment of water iron content, at the Bangladesh Council of Scientific and Industrial Research (BCSIR) in Dhaka, Bangladesh. The coefficient of variance (CV) between field-based and BCSIR results was 7 %.

Statistical Analyses Tube well characteristics and water analysis Tube well characteristics and groundwater quality information was collected in both rounds. Tube wells newly identified in round 2 were analyzed twice, at least one month apart. The exact location, defined by latitude and longitude using a handheld Global Positioning System (GPS) unit (± 15 m, Garmin E-trex Legend®, Garmin, KS, USA), was recorded. The year of installation, depth (feet), and tube well ownership was collected by interview during the water analysis visit. Depth was estimated by asking the respondent, or tube well owner, the number of pipes used to sink

Complete water intake and iron concentration data was available for 276 (90 % of 307 enrolled) participants (Figure 1). Two hundred thirty-seven participants used the same drinking water tube well from round 1 to 2 while 39 participants changed their tube well. To represent participant exposure through follow-up, the mean of rounds 1 and 2 was used for pH, temperature, ORP, iron concentration, and daily drinking water intake. Mean pH and ORP were used to construct a Pourbaix diagram for iron species in water reflecting the thermodynamic theory (Nernst Equation) [32] and to explore the ratio of ferrous to ferric iron species.


8


Figure 1. Participation diagram. 1 Sampling frame consisted of 464 participants who, during participation in the original sub-study conducted from 2001 to 2007, contributed a live birth, completed a full panel of sub-study assessments during the 1st trimester (0 to 12 weeks of gestation) and 3 months postpartum (8 to 16 weeks after pregnancy) visits, and were confirmed as residents of the same household throughout sub-study follow-up.

Drinking water intake (± 0.1 L/day), overall and by collection method, was calculated by multiplying the drinking container volume by the number of containers consumed in the previous 24 hours. Total daily iron intake through drinking water (mg/day) was calculated by multiplying the iron concentration in the participant’s drinking water tube well (mg/L) by the volume of water she consumed in the previous 24 hours (L/ day), excluding the volume of water consumed after filtration due to the ability of filtration to remove nearly all iron from water [33]. Arsenic concentration was categorized with consideration of the drinking water guidelines as defined by WHO (10 cm/L) [34] and the Bangladesh government (50 cm/L) [9]: < 10 cm/L, 10 – < 50, 50 – < 100, and 100 – 500. Daily rice intake was calculated by multiplying the total number of servings consumed in the previous 24 hours by the weight (kg) of the selected serving of cooked rice determined during a calibration study. Food groups were defined for heme iron sources (red meat), other protein (chicken and fish), dairy, eggs, fruits, and dark green leafy vegetables. For each food group, mean intake frequency of round 1 and 2 was dichotomized to reflect consumption of 0 to 2 times or 3 or more times per week. To compare characteristic distributions at enrollment across participants with and without complete data, equality of proportions and Student’s t-tests or,

for categorical variables, Fisher's exact tests, were applied. Drinking water consumption patterns by rounds were assessed using paired Student’s t-tests. The distributions of groundwater characteristics were compared between rounds using Wilcoxon matched-pair, signedrank tests. Arsenic concentration was compared using Fisher’s exact test. Correlations between daily drinking water intake and water collection methods (defined as % of total drinking water intake), mealtime, rice intake, and body-mass index (BMI, kg/m2) were estimated using Pearson’s correlation coefficient. All analyses were performed using STATA statistical software package version 11.0 [35]. JiVitA and the current study were approved by the Bangladesh Medical Research Council, Dhaka, Bangladesh and the Institutional Review Board at the Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.

Results Participants’ characteristics did not differ at baseline by participation status. Among those included in all analyses, mean (SD) age was 24.6 (5.4) years and median [25th, 75th quartile, interquartile range (IQR)] parity was 2 (2, 3) offspring. Mean (SD) BMI (kg/ m2) and MUAC (cm) were 19.5 (2.7) and 23.9 (2.4), respectively. The median (IQR) number of years of education was 7 (4, 9) for the 62 % of subjects (n = 170) with any formal education. A majority (n = 249, 90 %) of the participants were Muslim. All participants used a tube well as their main drinking water source with a median (IQR) duration of use at round 1 of 5.0 (1.5, 9.0) years (Table I). A majority of tube wells were within 15 meters of the participant’s home and were owned by the participant’s family or a relative who owned the household in which she lived. Heme iron sources were rarely consumed (93 % consumed 0 to 2 times per week). Similarly, dairy, egg, and dark green leafy vegetable (DGLV) consumption was rare (67 %, 89 %, 75 %, respectively, consumed 0 to 2 times per week). Roughly half of participants consumed fruits 3 or more times a week (49 %). Other protein sources were often consumed 3 or more times a week (86 %) with fish constituting 95 % of reported intake for this food group. Mean (SD) rice intake was 1.6 (0.4) kg of cooked rice per day and consistent between rounds (p = 0.18 for difference between rounds). A majority of participants (73 %) used a stainless steel drinking container in both rounds with a mean (SD) volume of 290 (30) mL (range: 220, 410). Mean



9

Table I: Drinking water tube well characteristics at time of identification. Round 1 Newly identified tube wells

Year of installation

Depth (ft)

Ownership [n (%)

n

391

276

mean (SD)

2000.7 (6.5)

2002.9 (7.1)

median (IQR)

2002 (1998, 2005)

2006 (2000, 2008)

range

1953, 2008

1983, 2008

mean (SD)

47 (19)

49 (16)

median (IQR)

45 (35, 55)

45 (38, 57)

range

25, 186

26, 86

Personal

118 (42)

2 (10)

Relative

87 (32)

12 (57)

Shared

50 (18)

4 (19)

Neighbor

11 (4)

1 (5)

9 (3)

1 (5)

Public 1

Round 2

Data available for 21 of 39 tube wells with 1 additional missing for depth and 2 for ownership.

(SD) usual total daily drinking water intake was 2.7 (0.8) L or 61 (21) mL/kg. Following from a significant difference in the daily number of containers consumed by round [mean (95 % CI) difference (containers/day): 1.2 (0.8, 1.6) p < 0.001], a higher volume of drinking water was consumed in round 1 than in round 2 [mean (95 % CI) difference round 1 – round 2 (L/day): 0.4 (0.3, 0.5) p < 0.001]. Mean drinking water intake was positively correlated with BMI (kg/m2) and daily rice intake (r = 0.16 for both, p < 0.01) but was not associated with age (p > 0.15). Drinking water was consumed most commonly (60 %) within 5 minutes of pumping from the tube well, and 35 % was consumed within 5 and 30 minutes of pumping (Table II). The use of a filter was rare (1 % of all intake). Additionally, most water (78 %) was consumed with (i. e. immediately following) meals rather than between meals and was significantly correlated with the amount of rice consumed (kg cooked rice/day; r = 0.16, p < 0.01). Daily water intake was not associated with how or when the water was collected (p = 0.80, 0.72, 0.07, and 0.73, for less than 5 minutes, 5 to 30 minutes, more than 30 minutes, and filtered, respectively). Usual groundwater pH, temperature (oC), and ORP (Eh) were [median (IQR)] 6.8 (6.6, 7.2), 26.8 (26.5, 27.1), and – 151 (– 179, – 91), respectively and values were not meaningfully different by round. The Pourbaix diagram for iron species suggests that ferrous predominates over ferric as the iron species in water collected directly from the tube well (Figure 2). Arsenic concentration was below the Bangladesh govern-

Table II: Daily drinking water intake including collection method. Collection method

Volume (L/day)1

% of total

Overall

2.7 (0.8)

100

By time (minutes) since pumping from tube well Less than 5

1.6 (0.9)3

60

More than 5 but less than 302

1.0 (0.8)

35

More than 30

0.1 (0.2)

3

Filtered

0.0 (0.2)

1

Breakfast

0.7 (0.3)

27

Mid-morning

0.4 (0.3)

13

Lunch

0.6 (0.3)

21

Afternoon

0.2 (0.2)

7

Dinner

0.8 (0.3)

30

After dinner

0.1 (0.1)

3

By meal time

1

Data presented as mean (SD) and represents mean of rounds 1 and 2. 2 30 minutes approximated one meal-time. 3 Sum of components may not equal overall value because of rounding.

ment-defined health-based drinking water standard of 50 μg/L for 89 % and 92 % of tube wells in rounds 1 and 2, respectively, nearly all of which (79 % and 75 % of all tube wells, respectively) were also below the WHO drinking water guideline of 10 μg/L. Total iron con-


10


centration was similar across rounds [median (IQR) difference between rounds (mg/L): – 0.3 (– 2.7, 1.4) p = 0.08)] with a usual median (IQR) concentration of 16.3 (6.9, 28.2) mg/L (range: 0.8, 44.5). Median (IQR) iron concentration was 13.9 (5.7, 25.5) and 14.9 (5.0, 27.5) by round among those with arsenic concentration below the Bangladesh guideline. Iron concentration was significantly higher for tube wells with arsenic greater than 50 μg/L (p < 0.002 for both, difference in iron (mg/L) between high – low arsenic categories: 17.5 and 18.4 by round). Iron concentration was significantly correlated with tube well depth (r=0.23, p = 0.001). Accounting for usual water intake (excluding filtered water), participants consumed [median (IQR 41.1)] (16.0, 71.0) mg of iron per day through drinking water (Table III). Iron concentration significantly increased with higher participant-defined perception of iron levels in their tube well water [Figure 3, median (IQR) iron concentration (mg/L) by score: 1.5 (1.3, 3.8), 7.9 (3.3, 15.8), 14.6 (11.0, 26.3), and 27.0 (17.7, 31.8) for none, a little , a medium amount, and a lot respectively (n = 42, 65, 63, 105 by category), p < 0.0001]. Although daily drinking water intake was not related to perception score (p = 0.95 by ANOVA), iron intake through water increased with increasing score [median (IQR) mg/ day by score: 4.8 (3.3, 10.7), 23.8 (8.2, 45.7), 40.6 (24.1, 68.3), and 63.3 (45.1, 86.8), respectively, p < 0.0001].

Discussion This study, conducted among a population of women living in rural, northwestern Bangladesh has found that participants usually consumed 2.7 (0.8) L of drinking water per day, all of which was collected from tube wells located within 15 meters of the household. All tube wells consistently exceeded the WHO iron concentration cutoff of 0.3 mg/L and 90 % exceeded the WHO/FAO suggested limit of 2.0 mg/L emphasizing the presence of high iron levels most likely easily perceptible by taste and smell. As a result of the high iron concentration in the groundwater sources and preferred water collection methods, half of the participants consumed 41 mg or more of iron per day through drinking water alone. A vast majority (90 %) consumed water that had arsenic levels below the Bangladeshi government guideline (< 50 μg/L) and 75 % of participants were exposed to drinking water with arsenic below the WHO guideline of 10 μg/L. This study has shown that seventy-three percent (73 %) of participants chronically consume more than

Figure 2. Pourbaix diagram1 to estimate ratio of ferrous to ferric iron in groundwater samples adapted from the Nernst equation. 1 Adapted from [32] Table III: Daily drinking water consumption and iron intake through drinking water. Variable Drinking water intake1 (L/day) Drinking water concentration (mg/L) Daily iron intake through drinking water2 (mg/day)

Value mean (SD)

2.7 (0.9)

median (IQR)

2.6 (2.1, 3.3)

range

0.0, 5.9

mean (SD)

17.8 (12.2)

median (IQR)

16.3 (6.9, 28.2)

range

0.8, 44.5

mean (SD)

46.2 (35.4)

median (IQR)

41.1 (16.0, 71.0)

range

0.0, 154.7

1

Drinking container volume (L) X containers consumed (± 0.5 containers/day) excluding filtered water. 2 Drinking water iron concentration (mg/L) X Drinking water intake (L/day, excluding filtered water).

the Recommended Dietary Allowance (RDA) for iron for adult women of 18 mg/day and 46 % consume more than the recommended Tolerable Upper Intake Level (UL) of 45 mg iron/day [36] from drinking water alone. The study was not designed to quantitatively assess iron intake and, therefore, is limited with regard to estimating the proportion of totally daily iron intake provided by groundwater. In this context of a large, community-based field trial, 24-hour recalls, enabling the calculation of nutrient intake, are challenging to conduct. Instead, we assessed diet using repeat 7-day food frequency questionnaires (FFQ) shown to reflect individual intake pattern when averaged over time [37, 38]. FFQ results indicate that this population



Figure 3. (A) Total groundwater iron concentration (mg/L); (B) Daily drinking water intake (L/day) reported by women; and, (C) Daily iron intake by women through drinking groundwater (mg/day) by perceived amount of iron in tube well water based on question “How much iron do you think is in the water that you pump from this drinking water tube well?” asked at the first assessment visit for a tube well. Boxes represent interquartile range with horizontal line at median, fences drawn at most extreme observation equal to or less than respective quartile +/– 1.5*interquartile range and outliers. n = 42, 65, 63, 105 in perceived ‘none,’ ‘a little,’ ‘a medium amount,’ and ‘a lot,’ respectively. Total groundwater iron concentration and daily iron intake through groundwater significantly increased by perceived iron level (p < 0.0001 by Kruskal-Wallis).

11

consumes a typical Bangladeshi rice based diet low in heme iron sources with frequent fish consumption [39]. Results from large-scale dietary surveys in Bangladesh conducted in 1981 to 1982 and 1995 to 1996 suggest that average daily dietary iron intake may range from [mean (SD)] 24 (1.6) mg to 29 (1.0) mg depending on the season [40]. The source of dietary iron was not detailed in the report; however, another dietary study conducted in rural Bangladesh in 1996 and 1997 estimated from 4 repeat 24-hour recalls that only 5 % of daily iron was provided by meat, fish, and poultry [41]. This information suggests that in this environment a majority of dietary iron is non-heme, most likely with low bioavailability. Diet composition, particularly among this population where a majority of drinking water (78 %) was consumed with, rather than between, meals [42], may influence groundwater iron absorption. For example, the high level of iron absorption inhibitors found in the typical Bangladeshi diet, such as phytic acid in rice and legumes, may reduce the proportion of groundwater iron that is absorbed [43]. It is also important to note that rice consumption and water intake were positively correlated, possibly enabling a higher iron intake to combat increased absorption inhibition caused by rice. The form of iron consumed through drinking may impact the bioavailability or amount that is absorbed [44]. Our results corroborate information from other groundwater studies that suggest the aquifer environment in the area is a reducing one [9] and that the ratio of ferrous, the most bioavailable form of iron [43], to ferric iron is large. Additionally, Roberts et al. [45] sampled groundwater in Bangladesh and reported that nearly all (99 %) of the total iron was dissolved. Based on water quality studies in similar settings, this exposure may be reasonably constant over many years [45, 46]. With exposure to air and heat, such as sunlight, soluble ferrous iron will begin to oxidize into insoluble ferric iron [47, 48]. It is important to note that most drinking water was consumed within 5 minutes of pumping from the tube well, well before oxidation may lower the ferrous to ferric ratio. This water consumption preference further suggests that the common ways by which women in this environment drink their water may ensure that most of the dissolved iron naturally found in the groundwater is consumed in highly bioavailable ferrous iron. Participants were able to accurately perceive the magnitude of iron in their water using a four-point scale representing none, a little, a medium amount, and a lot when asked about the amount of iron they thought was in the water pumped from their drinking well. It may be that perceptions were influenced by


12


negative organoleptic characteristics they noticed in their water relative to nearby water sources. This finding is further supported by results from a study areawide survey [49]. Given the accuracy of the simple question we asked, it could be added to surveys in areas where groundwater is consumed to qualitatively assess exposure to dissolved iron, notwithstanding that actual median iron concentrations by category of perception may vary by local groundwater iron concentration distributions [50]. In conclusion, we have found that in areas like Bangladesh where groundwater has elevated and variable levels of natural iron, tube wells provide proximate water sources that supply a chronic daily source of supplemental, mostly ferrous, iron through drinking. As a result, groundwater offers a currently underappreciated source of dietary iron, which is overlooked using conventional dietary assessments. This study has also shown that the measurement of daily drinking water intake and collection practices along with iron concentration in that water could be relatively easily incorporated into dietary intake assessments. This exposure may be healthful in an environment with minimal bioavailable iron in the typical diet and may contribute to a reduced risk of iron deficiency, especially among women of reproductive age. Understanding the impact on nutritional status associated with the chronic consumption of water with elevated levels of dissolved iron is of interest.

Acknowledgements We would like to thank the JiVitA field technicians for their diligent field work and the GIS team for supporting the field activities throughout the study. We would also thank Dr. Mahbubur Rashid, Dr. Shafiul Md, Azaduzzaman, Rashidul Hasan, and Mahbubul Islam for their supervisory assistance, and other members of the JiVitA research team for excellent administrative and logistical support. We appreciate the laboratory assistance provided by M. Azizul Islam Kazi and his laboratory team at the Analytical Research Division, Bangladesh Council of Scientific and Industrial Research (BCSIR) Laboratory, Dhaka.

References 1. Andrews, N. and Schmidt, P. (2007) Iron homeostasis. Annu. Rev. Physiol. 69, 85.

2. McLean, E., Cogswell, M., Egli, I., Wojdyla, D. and de Benoist, B. (2009) Worldwide prevalence of anaemia, WHO Vitamin and Mineral Nutrition Information System, 1993 – 2005. Public Health Nutr. 12, 444 – 454. 3. Stoltzfus, R.J. (2003) Iron deficiency: global prevalence and consequences. Food Nutr. Bull. 24, S99 – 103. 4. Milman, N. (2008) Prepartum anaemia: prevention and treatment. Ann. Hematol. 87, 949 – 959. 5. Stoltzfus, R.J. and Dreyfuss, M.L. (1998) Guidelines for the use of iron supplements to prevent and treat iron deficiency anemia. ILSI Press, Washington, D.C. 6. Mehansho, H. (2006) Iron fortification technology development: New approaches. J. Nutr. 136, 1059 – 1063. 7. Gomez-Galera, S., Rojas, E., Sudhakar, D., Zhu, C., Pelacho, A., Capell, T. and Christou, P. (2010) Critical evaluation of strategies for mineral fortification of staple food crops. Transgenic Res. 19, 165 – 180. 8. Lindstrom, E., Hossain, M., Lonnerdal, B., Raqib, R., Arifeen, S. and Ekstrom, C. (2010) Prevalence of anemia and micronutrient deficiencies in early pregnancy in rural Bangladesh, the MINIMat trial. Acta Obstet. Gynecol. Scand. Accepted Article. 9. Kinniburgh, D.G. and Smedley, P.L. (2001) Arsenic contamination of groundwater in Bangladesh. Volume 1: Summary. 2001. Keyworth, British Geologic Survey. British Geologic Survey Report WC/00/19. 10. Deveau, M. (2010) Contribution of drinking water to dietary requirements of essential metals. J. Toxicol. Environ. Health A 73, 235 – 241. 11. World Health Organization (1984) Guidelines for drinking-water quality: Health criteria and other supporting information, 1st ed., Vol. 2, Geneva, Switzerland. 12. Briend, A., Hoque, B. and Aziz, K. (1990) Iron in tubewell water and linear growth in rural Bangladesh. Arch. Dis. Child. 65, 224 – 225. 13. Worwood, M., Evans, W., Villis, R. and Burnett, A. (1996) Iron absorption from a natural mineral water (Spatone Iron-Plus). Clin. Lab. Haematol. 18, 23 – 27. 14. World Health Organization. (2005) Nutrients in drinking water. Geneva, Switzerland. 15. World Health Organization. (2006) Guidelines for drinking-water quality: incorporating the first addendum. 3rd ed., Vol. 1 Recommendations, Geneva, Switzerland. 16. World Health Organization. (2004) Water, sanitation and hygiene links to health. Geneva, Switzerland.



17. Brinkel, J., Khan, M. and Kraemer, A. (2009) A systematic review of arsenic exposure and its social and mental health effects with special reference to Bangladesh. Int. J. Environ. Res. Public Health 6, 1609 – 1619. 18. Rahman, M., Ng, J. and Naidu, R. (2009) Chronic exposure of arsenic via drinking water and its adverse health impacts on humans. Environ. Geochem. Health 31, 189 – 200. 19. Wasserman, G., Liu, X., Parvez, F., Ahsan, H., Levy, D., Factor-Litvak, P., Kline, J., van Geen, A., Slavkovich, V. et al. (2009) Water manganese exposure and children's intellectual function in Araihazar, Bangladesh. Environ. Health Perspect. 114, 124 – 129. 20. Vahter, M. (2009) Effects of arsenic on maternal and fetal health. Annu. Rev. Nutr. 29, 399. 21. Faruque, S.M., Naser, I.B., Islam, M. J., Faruque, A.S.G., Ghosh, A.N., Nair, G.B., Sack, D.A. and Mekalanos, J.J. (2005) Seasonal epidemics of cholera inversely correlate with the prevalence of environmental cholera phages. Proc. Natl. Acad. Sci. USA 102, 1702 – 1707. 22. Milton, A., Rahman, H., Smith, W., Shrestha, R. and Dear, K. (2006) Water consumption patterns in rural Bangladesh: are we underestimating total arsenic load? J. Water Health 4, 431 – 436. 23. West, K.P., Jr., Christian, P., Klemm, R., Labrique, A., Rashid, M., Shamim, A., Katz, J. and Sommer, A. (2006) The JiVitA Bangladesh Project: Research to improve nutrition and health among mothers and infants in rural South Asia. Sight and Life Newslett. 1, 10 – 14. 24. Labrique, A., Christian, P., Klemm, R., Rashid, M., Shamim, A., Massie, A., Schulze, K., Hackman, A. and West Jr., K. (2010) A cluster-randomized, placebo-controlled, maternal vitamin A or beta-caraotene supplementation trial in Bangladesh: design, methods, and innovations. BMC Trials. Article Accepted. 25. United Nations Children Fund Bangladesh Bureau of Statistics. (2007) Progotir Pathey 2006, Volume 1: Technical Report. Dhaka, Bangladesh, United Nations Children's Fund and Bangladesh Bureau of Statistics. 26. Tetens, I. and Thilsted, S. (2004) Rice in the Bangladeshi context: consumption, preferences, and contribution to energy intake and satiety. In: Alleviating malnutrition through agriculture in Bangladesh: biofortification and diversification as sustainable solutions (Roos, N., Bouis, H., Hassan, N. and Kabir, K., eds.), pp. 40 – 43. IFPRI, Washington, D.C. 27. Torlesse, H., Moestue, H., Hall, A., de Pee, S., Kiess, L. and Bloem, M. (2004) Dietary diversity

13

in Bangladesh: evidence from the Nutritional Surveillance Project. In: Alleviating malnutrition through agriculture in Bangladesh: Biofortification and diversification as sustainable solutions (Roos, N., Bouis, H., Hassan, N. and Kabir, K., eds.), pp. 44 – 49. IFPRI, Washington, D.C. 28. Sawka, M.N., Cheuvront, S.N. and Carter, R., III. (2005) Human water needs. Nutr. Rev. 63, S30-S39. 29. Zerfas, A.J. (1975) The insertion tape: a new circumference tape for use in nutritional assessment. Am. J. Clin. Nutr. 28, 782 – 787. 30. Gibson, R.S. (2005) Principles of Nutritional Assessment, 2nd ed., Oxford University Press, New York. 31. Merrill, R., Shamim, A., Labrique, A., Ali, H., Schulze, K.J., Rashid, M., Christian, P. and West, K.P., Jr. (2009) Validation of two porTable Instruments to measure iron concentration in groundwater in rural Bangladesh. J. Health Popul. Nutr. 27, 414 – 418. 32. Snoeyink, V. and Jenkins, D. (1980) Water chemistry. John Wiley & Sons Inc., New York. 33. Huisman, L. and Wood, W. (1974) Slow sand filtration. Belgium, World Health Organization, Geneva, Switzerland. 34. World Health Organization (2004) Guidelines for drinking-water quality, 3rd ed., Vol. 1. Geneva, Switzerland. 35. StataCorp (2009) Stata Statistical Software: Release 11. Vol. 11.0. StataCorp LP, College Station, TX. 36. National Academies Press. (2001) Dietary reference intakes for vitamin A, vitamin K, arsenic, boron, chromium, copper, iodine, iron, manganese, molybdenum, nickel, silicon, vanadium, and zinc. Washington, D.C. 37. Feskanich, D., Rimm, E. B., Giovannucci, E.L., Colditz, G., Stampfer, M.J., Litin, L.B. and Willett, W.C. (1993) Reproducibility and validity of food intake measurements from a semiquantitative food frequency questionnaire. J. Am. Diet. Assoc. 93, 790 – 796. 38. Willet, W.C. (1990) Validity of food-frequency questionnaires. In: Nutritional epidemiology , pp. 92 – 126. Oxford University Press, New York. 39. Thorne-Lyman, A.L., Valpiani, N., Sun, K., Semba, R.D., Klotz, C.L., Kraemer, K., Akhter, N., de Pee, S., Moench-Pfanner, R. et al. (2010) Household dietary diversity and food expenditures are closely linked in rural Bangladesh, increasing the risk of malnutrition due to the financial crisis. JN 140, 182S-188S. 40. Hels, O., Hassan, N., Tetens, I. and Haraksingh, T.S. (2003) Food consumption, energy and nutrient intake


14


and nutritional status in rural Bangladesh: changes from 1981 – 1982 to 1995 – 96. Eur. J. Clin. Nutr. 57, 586 – 594. 41. Bouis, H. (2004) Relating the Bangladeshi diet to iron deficiency. In: Alleviating malnutrition through agriculture in Bangladesh: biofortification and diversification as sustainable solutions (Roos, N., Bouis, H., Hassan, N. and Kabir, K., eds.), pp. 50 – 60. IFPRI, Washington, D.C. 42. Hurrell, R. and Egli, I. (2010) Iron bioavailability and dietary reference values. Am. J. Clin. Nutr. 91, 1461S1467. 43. Hallberg, L. (1981) Bioavailability of dietary iron in man. Annu. Rev. Nutr. 1, 123 – 147. 44. Anderson, G.J., Frazer, D.M. and McLaren, G.D. (2009) Iron absorption and metabolism. Curr. Opin. Gastroenterol. 25, 129 – 135. 45. Roberts, L.C., Hug, S.J., Dittmar, J., Voegelin, A., Saha, G.C., Ali, M. A., Badruzzaman, A. B. and Kretzschmar, R. (2007) Spatial distribution and temporal variability of arsenic in irrigated rice fields in Bangladesh. 1. Irrigation water. Environ. Sci. Technol. 41, 5960 – 5966. 46. Steinmaus, C.M., Yuan, Y. and Smith, A.H. (2005) The temporal stability of arsenic concentrations in well water in western Nevada. Environ. Res. 99, 164 – 168. 47. Sharma, A. and Tjell, J. (2003) Can water storage habits influence the cancer risk of drinking arsenic

contaminated water? In: Fate of arsenic in the environment. (Ahmed, M., Ali, M. and Adeel, Z., eds.), pp. 37 – 57. The United Nations University, Dhaka, Bangladesh. 48. Todd, D. (1959) Ground water hydrology. John Wiley and Sons, Inc., New York City. 49. Merrill, R., Labrique, A., Shamim, A., Schulze, K.J., Christian, P. and West, K.P., Jr. (2010) Elevated and variable groundwater iron in rural northwestern Bangladesh. J. Water Health 8, 818 – 825. 50. Dietrich, A. (2006) Aesthetic issues for drinking water. J. Water Health 4, 11 – 16. 51. Labrique, A., Christian, P., Klemm, R., Rashid, M., Shamim, A., Massie, A., Schulze, K., Hackman, A. and West Jr., K. A. (2011) A cluster-randomized, placebo-controlled, maternal vitamin A or beta-carotene supplementation trial in Bangladesh. Trials 12, 102. Alain B. Labrique, MHS, MS, PhD Assistant Professor Center for Human Nutrition Department of International Health Office: W5543 615 N. Wolfe St. JHBSPH Baltimore, MD 21205 USA Tel.: +1 (443) 287 - 4744 Fax: +1 (410) 510 - 1055 E-mail: [email protected]
