How Much Arsenic in U.S. Rice?
In a market-basket survey published in Environmental Science & Technology, researchers found that arsenic levels in U.S. rice varied significantly by region.
Specifically, rice grown in the south central U.S. (Arkansas, Louisiana, Mississippi, Texas, & Missouri) was on average 41% higher in arsenic than rice grown in California (0.27 mcg/g verus 0.16 mcg/g).
The scientists hypothesized that the higher level of arsenic found in south central U.S. rice could be attributed to the arsenic-containing pesticides previously used on the cotton fields that are now used for growing rice. Industry is currently trying to develop strains of rice that take up less arsenic from the soil.
Assessing Risk
Presently the government sets no maximum contaminant level for arsenic in food. The EPA has set a 10 mcg per liter limit for inorganic arsenic in drinking water.
The average consumption of rice in the U.S. is 25 grams per day. However, some ethnic groups, as well as people pursuing a gluten-free diet (e.g., individuals with Celiac diesease or on the autistic spectrum), may eat much more, and thus may be at risk for higher arsenic exposure. Also, as the researchers note, young children tend to eat much larger portions of rice relative to their small size.
Previous studies suggest that the percentage of inorganic arsenic (the most toxic form) found in U.S. rice varies widely, from 10% to 70% of the total arsenic in the rice. A person eating an average rice portion size of 100 grams with an arsenic content of 0.3 mcg/g would ingest 30 mcg of arsenic. If 50% of that arsenic were inorganic, total dietary exposure from rice alone would be 15 mcg, exceeding the EPA limit for a liter of water.
A market-basket survey has limitations, as the tested products are purchased at stores and cannot be traced to individual farms. Soil arsenic concentrations can vary greatly by location within regions, so it probably makes sense to monitor and survey individual farms to identify locations, crop management techniques, and types of rice that might affect actual levels.
Effects of Chronic Arsenic Exposure
Common signs and symptoms of chronic arsenic poisoning include:
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Neuropathy - pins/needles/numbness in the feet or hands
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Diminished tendon reflexes
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Skin problems - hyperpigmentation, hyperkeratosis (bumps, skin eruptions)
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Anemia, leukopenia
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Mees lines - horizontal white lines on the fingernails
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(Long-term: cancer - arsenic is a carcinogen.)
Other non-specific symptoms common to heavy metal toxicity may also appear, such as headaches, fatigue, insomnia, restlessness, malaise, abdominal pain, racing heart, and cognitive decline. (Source: Andrew Cutler - Hair Test Interpretation: Finding Hidden Toxicities)
What You Can Do
You can call the manufacturer of the rice that you buy and ask if the rice is tested for arsenic content. It’s unlikely, given that testing is not required and results can vary significantly by farm, but it’s worth a shot. At least they’ll know that you view heavy metal contamination as an important issue.
You can buy rice grown in regions that may have lower arsenic soil content on average (e.g., California).
If you do suspect arsenic poisoning may be affecting you, a hair test can be useful, as hair levels of arsenic reliably reflect overall body levels. However, if exposure was years ago, hair levels may be low, while arsenic bound to tissues may remain high. Blood and urine tests are not reliable indicators for chronic, low-level arsenic exposure.
Arsenic is ideally removed from the body via a safe (low/frequent-dose) chelation protocol. Alpha-lipoic acid is the best arsenic chelator.
Also, some arsenic is naturally removed from the body through methylation, so making sure that the methylation pathways are working well (e.g., ensuring adequate supply of methylators - vitamin B12, folic acid, DMG, TMG, etc.) is important.
You can learn more about my approach for helping people with heavy metal toxicity issues on my main website.
Related Posts
Toxic Waste in Fertilizer — And Your Food
EPA Again Says No to Cancer-Causing Chemicals in Wood Products
Alpha-Lipoic Acid - Anti-aging with a Big Asterisk
(Image: USDA - Keith Weller)
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July 10th, 2007 at 6:59 pm
Marc, wouldn’t buying organic rice ensure (for the most part) that arsenic levels are low? A farmer has to wait something like 3 years before he can sell organic product from a converted field. Don’t know if that’s long enough to get rid of all the arsenic so i guess knowing where your rice comes from is key! I’ll have to ask Rainbow Market where they get their organic rice next time I’m in the store. Hopefully it’s not from the South Central US.