Estimating Inorganic Arsenic Exposure from U.S. Rice and Total Water Intakes

Overview

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Key numbers

The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:

Madhavi Mantha,1,2 Edward Yeary,2,3 John Trent,2,3 Patricia A. Creed,2 Kevin Kubachka,4 Traci Hanley,4 Nohora Shockey,4
Douglas Heitkemper,4 Joseph Caruso,5 Jianping Xue,6 Glenn Rice,7 Larry Wymer,2 and John T. Creed2
the Second Six-Year Review data set. To estimate the distribution of iAs concentrations in rice ingested by U.S. consumers, 54 grain-speciﬁc, produc-
water and rice were 4:2 lg=day and 1:4 lg=day, respectively, for the entire U.S. population. The Tribal, Asian, and Paciﬁc population exhibited the
highest mean daily exposure of iAs from cooked rice (2:8 lg=day); the mean exposure rate for children between ages 1 and 2 years in this population
CONCLUSIONS: An average consumer drinking 1.5 L of water daily that contains between 2 and 3 ng iAs=mL is exposed to approximately the same
amount of iAs as a mean Tribal, Asian, and Paciﬁc consumer is exposed to from rice. https://doi.org/10.1289/EHP418
Introduction study (Meacher et al. 2002)) limit their usefulness for estimating
inorganic arsenic (iAs) as a Class 1 carcinogen (IARC 2004). In each of these previous iAs intake assessments, information
by the World Health Organization (WHO 1993) and the U.S. based on samples collected from two U.S. cities in 1997 (Schoof
Environmental Protection Agency (EPA 2001). Among nonoccu- et al. 1999b). Xue et al. (2010) and Yost et al. (2004) estimated
pationally exposed U.S. residents, drinking water and diet are that rice consumption contributes approximately 20% of the
iAs is the primary form of arsenic (As), while in food matrices di- et al. (2004) estimated that, for children at the 95th percentile,
etary As speciation techniques are used to diﬀerentiate iAs from rice consumption contributes 50% of the total iAs exposure. A
Table S1 summarizes published probabilistic models that esti- tance of rice consumption to total iAs exposures (Meliker et al.
mate U.S. iAs exposures (Meacher et al. 2002; Schoof et al. 2006).
1999a; Tsuji et al. 2007; Xue et al. 2010; Yost et al. 1998; Yost Because rice consumption contributes to total dietary iAs expo-
et al. 2004). Predicted iAs exposures from drinking water intakes sure in the U.S. population, the authors of the studies in Table S1
range from 1:75 to 2:5 lg=day, while dietary iAs estimates range highlighted the need for collecting speciated As data from dietary
from 3:1 to 3:6 lg=day. Each of these assessments uses iAs drink- samples to address this source of uncertainty. In response, the U.S.
ing water concentration data collected between 1980 and 1998. Food and Drug Administration (FDA) measured speciated As lev-
The age of these data, given changes in treatment and water sour- els in 1,300 samples of rice and rice-containing products (FDA
ces, and the relatively small sample size (n = 500) utilities in one 2013). Less stratiﬁed literature surveys of iAs species in rice sug-
gest the ranges are 0:01–0:379 lg=g for iAs and 0:004-0:9 lg=g
for dimethylarsenic acid (DMA) (Ackerman et al. 2005;
Address correspondence to J.T. Creed, U.S. EPA, 26 W. Martin Luther King Heitkemper et al. 2009; Heitkemper et al. 2001; Lamont 2003;
Dr., Cincinnati, OH 45268 USA. Telephone: (513) 569-7833. E-mail: creed. Laparra et al. 2005; Meharg et al. 2009; Torres-Escribano et al.
jack@epa.gov 2008; Trenary et al. 2012; Williams et al. 2005; Zavala et al. 2008;
Supplemental Material is available online (https://doi.org/10.1289/EHP418).
Zhu et al. 2008), with some reports of monomethylarsonic acid
Received 31 July 2015; Revised 2 May 2016; Accepted 18 July 2016; (EFSA 2014) recently developed an As exposure assessment based
Published 30 May 2017. on 353 rice samples; the mean and standard deviation of the iAs
content is accessible to all readers. However, some ﬁgures and Supplemental 0:152 ± 0:05, 0:089 ± 0:03, and 0:105 ± 0:06 lg=g, respectively.
Material published in EHP articles may not conform to 508 standards due to
will work with you to assess and meet your accessibility needs within 3 studies have been conducted in swine (Brattin and Casteel 2013;
working days. Juhasz et al. 2006, 2008; Rodriguez et al. 1999) and mice
Environmental Health Perspectives 057005-1
(Bradham et al. 2011), the high cost of these studies has led to de- composites were formulated by dividing the grain-type-speciﬁc
(Ackerman et al. 2005; Alava et al. 2012; He et al. 2012; Laparra mills and then multiplying by 100 to obtain a percentage.
et al. 2005; Sun et al. 2012; Trenary et al. 2012) and human Summation of these grain speciﬁc percentages for all mills is the
in vivo bioaccessibility (solubilized in the gastrointestinal tract basis for the pie chart in Figure 1. The individual mill- and grain-
but not necessarily absorbed) approaches (He and Zheng 2010) to speciﬁc weighting factors were then used to create the domestic

Methods (brief)

by the World Health Organization (WHO 1993) and the U.S. based on samples collected from two U.S. cities in 1997 (Schoof
from 3:1 to 3:6 lg=day. Each of these assessments uses iAs drink- samples to address this source of uncertainty. In response, the U.S.
ing water concentration data collected between 1980 and 1998. Food and Drug Administration (FDA) measured speciated As lev-
The age of these data, given changes in treatment and water sour- els in 1,300 samples of rice and rice-containing products (FDA
ces, and the relatively small sample size (n = 500) utilities in one 2013). Less stratiﬁed literature surveys of iAs species in rice sug-
for dimethylarsenic acid (DMA) (Ackerman et al. 2005;
Published 30 May 2017. on 353 rice samples; the mean and standard deviation of the iAs
Dose Simulation (SHEDS) model (Xue et al. 2012) to estimate samples, but several of the small production mills were added to-
iAs exposures from drinking water and rice consumption gether to make one composite, while the eight weekly samples
in the United States, addressing concerns identiﬁed previously from a larger mill were split into two sets of four samples each to
drinking water database (U.S. EPA 2010), which sampled tive weighting factor was halved. When multiple weekly samples
any previous study and provides iAs estimates in 20 states not to equally weight these weekly samples into one sample before
from the drinking water used to cook the rice based on the with this sampling approach. Import rice samples were collected
Next, utilizing an in vitro extraction procedure that simulates samples collected from each city, and the India basmati samples
solid rice sample) As speciation-based analysis using ion chroma- Cooking, Subsampling, and Speciation of the 54
tography inductively coupled plasma-mass spectrometry (IC- Rice Composites
ICP-MS). Finally, using the rice ingestion rates from the The “Analysis” section in Figure 1 provides a block diagram
2001−2006 What We Eat in America (WWEIA) database summarizing the analysis of the composite rice samples. A 50-g

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

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Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

Commit	Date	Change	Description
3171d06	2026-08-02	major	1 section added
bc84bfc	2026-08-02	major	6 sections added; narrative text revised