TatahMentan 2020 - Rice and other grain elements

TatahMentan and colleagues measured toxic and essential elements in rice and other grains purchased from Louisiana retail stores. The occurrence-relevant toxic elements were total arsenic, lead, and cadmium, reported on a dry-weight basis for U.S. white rice, imported white rice, U.S. brown rice, and a grouped “other grains” category. The study also analyzed rinse-washed white rice for selected elemental-loss comparisons.

Key numbers

The methods state that 28 white rice and 11 brown rice samples were purchased from local stores in Louisiana. White-rice package labels identified production in the US states of California, Texas, and Louisiana and in Thailand, Italy, and India. Brown-rice samples were produced in Louisiana, Arkansas, and Texas. Other grains included lentils, barleys, beans, oats, wheat, and pea samples from Canada and U.S. states; the extracted text does not state a total other-grain sample count.

Table 1 reports toxic elements as median percentiles plus mean/min-max in µg/kg (Dry Weight):

The Results text states the toxic-element medians as 131 (90-157), 2.8 (2.4-5), and 6.5 (4.7-12) for As, Pb, and Cd in U.S. white rice; 155 (93-167), 3.6 (2.5-7.6), and 8.4 (5.1-17) for imported white rice; 217 (180-291), 4.5 (2.6-11), and 17.4 (9.5-42) for U.S. brown rice; and 5.4 (3.2-9.1), 4.6 (3.5-8), and 6.7 (2.6-49) for other grains, all in µg/kg.

The discussion reports that six brown rice samples and one white, long grain rice from the US exceeded the Codex inorganic-arsenic rice limit cited by the authors, 200 µg/kg. Because this study measured total arsenic, that exceedance statement should remain source context rather than an inorganic-arsenic occurrence value.

Table 2 reports rinse washing for 9 white-rice samples compared with 19 unwashed white-rice samples. Washed white rice had mean Pb 4.3 µg/kg, Dry Weight versus unwashed white rice 10 µg/kg, Dry Weight, a 57 percent elemental loss; washed white rice had mean Cd 7.0 µg/kg, Dry Weight versus unwashed white rice 13 µg/kg, Dry Weight, a 46 percent elemental loss. Arsenic was not listed in the rinse-loss table.

Methods (brief)

Samples were powdered, digested using nitric acid, hydrochloric acid, and hydrogen peroxide, and analyzed by Agilent 7900 ICP-MS. The digestion used about 0.1 g of sample and overnight hotplate stages at 75 °C and 100 °C. Nine randomly selected white-rice samples were rinse-washed three times with ultrapure distilled water, dried at 80 °C for three hours, powdered, and analyzed using the same procedure. Quality control used NIST 1568b rice standard reference material, and mean recoveries for toxic and essential elements ranged from 78 to 110%.

Implications

This source contributes dry-weight occurrence evidence for rice and grouped non-rice grains in the U.S. retail context, with additional package-origin information for imported rice. It supports rice-bulk-grain and other-grain routing for total arsenic, lead, and cadmium. Because arsenic was measured by total-element ICP-MS and not speciated, the arsenic values remain tAs and must not be pooled as inorganic arsenic.

Verification notes

• PDF text was extracted with pdftotext -layout; title/byline, abstract, sample collection, digestion/ICP-MS methods, Table 1, Table 2, toxic-element Results, and discussion exceedance statement were checked in /tmp/f3_unrepresented_texts/tatahmentan2020.txt.
• DOI 10.3390/ijerph17218128, raw handle MFK_tatahmentan2020, and cite-key searches found no existing source page before creation.
• Units are preserved as source-reported µg/kg (Dry Weight), mg/kg (Dry weight), and percentages; no conversion was performed.
• Speciation: arsenic is total arsenic by ICP-MS. The source discusses an inorganic-arsenic standard, but no inorganic arsenic was measured.
• Brand firewall: rice and grain retail product brands were not named in the extracted text used for this page.
• Frontmatter slugs were checked against docs/gpt-collaboration/taxonomy-snapshot.md; no closed-vocabulary ingredient slug exists for barley or peas, so they are represented through broad cereals, non-rice grains, and legumes.

Page history

The five most recent substantive edits to this page. 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.