Effects of prolonged arsenic exposure in Bangladesh. Source: Flickr

Effects of prolonged arsenic exposure in Bangladesh. Source: Flickr

From the Roman Empire to the Renaissance, arsenic was the poison of choice. Odorless, tasteless, and colorless, it could be used in a single large dose or used to slowly weaken one over the course of months (1). Its use waned as methods of arsenic detection developed. However, natural deposits and pollution remain a source, and arsenic continues to seep into water sources. It, as discovered by the Toxic Metals Program at the Dartmouth Medical School, has even made its way into baby formulas (2). While arsenic research typically focuses on its incidence in drinking water, Dartmouth researchers have studied this silent killer’s travel through plants and food (3).

Exposure can lead to increased heart and lung disorders as well as diabetes and cancer (3). Its prolonged incidence in water sources and food has placed it first in the priority list of hazardous substances by the Agency for Toxic Substances & Disease Registry (4). Arsenic does not naturally break down in the environment and lingers in soil. In Bangladesh and India, 200 million people are exposed to arsenic from well water through drinking, and such exposure is not limited to developing nations.

In 2001, the Environmental Protection Agency changed its public drinking water limit from 50 to 10 ppb (3). But 40% of New Hampshire residents drink from private wells, which are not subject to EPA standards. One in every five wells contains high arsenic levels, and the Toxic Metals Program encourages users to conduct yearly checks (3).

Plants—in particular, those labeled hyperaccumulators—can absorb arsenic in soil. For example, arsenic does not harm rice when absorbed through water and can be consumed undetected (3). In an experiment by the National Health and Nutrition Examination Survey, urine samples were taken from 3633 rice consumers, and subjects that had one rice food item before sampling had a 44% greater urinary arsenic level (2).

The Toxic Metals Program has revealed brown rice syrup as a common hidden source (5). Used as an alternative to high fructose corn syrup, a known contributor to obesity, brown rice syrup has become more prevalent as the organic alternative.

Professor Brian Jackson, the director of the Trace Element Analysis Core Facility at Dartmouth, leads low-level trace metal analysis and speciation of environmental biological samples in the Toxic Metals Program (2). Last February, Jackson et al. published a paper outlining the concentrations of arsenic in commercial food products such as baby formula, cereal bars, and energy foods. Of the 17 baby formulas that his team picked up from a local Hanover store, two included brown rice syrup, and both had arsenic levels 20 times higher than recorded from the other formulas (4). One had arsenic levels six times higher than the EPA’s 10 ppb limit for drinking water.

The paper, published in a NIH journal, brought about a flurry of alarmed responses from parents and consumers. Only limited research has been conducted on the effects of arsenic in young children, but it is comforting to note than in trace amounts, arsenic typically leaves the system after two or three days (6).

Another Toxic Metals project is the Arsenic Uptake, Transport, and Accumulation in Plants led by Professor Mary Lou Guerinot. It studies the genetic control of arsenic uptake in plants and ultimately aims to protect food from contamination (7). Arsenic comes in two basic forms. In organic arsenic, arsenic is bound to organic elements, while inorganic arsenic is more toxic and comes bound to inorganic elements. Under 50% of American rice contains inorganic arsenic, while the same is true for 80% of Bangladeshi rice (7). The group’s research looks into genetic differences between plant species that control this difference.

The Dartmouth Toxic Materials Program has already taken significant strides in its understanding of arsenic, but much more research is necessary to master the element and its behavior.

References:

  1. Arsenic: A Murderous History.  Available at: https://sites.dartmouth.edu/toxmetal/arsenic/arsenic-a-murderous-history/ (15 February 2013)
  2. Arsenic in Food. Available at: https://sites.dartmouth.edu/toxmetal/arsenic/arsenic-in-food/ (25 February 2013)
  3. Why Arsenic? Available at: https://sites.dartmouth.edu/toxmetal/arsenic/ (15 February 2013)
  4. Priority List of Hazardous Substances (2011) Available at: http://www.atsdr.cdc.gov/SPL/index.html (23 February 2013)
  5. J. Blumberg, Organic Food Sweetener May Be a Hidden Source of Dietary Arsenic (2012). Available at: http://now.dartmouth.edu/2012/02/organic-food-sweetener-may-be-a-hidden-source-of-dietary-arsenic/ (23 February 2013)
  6. FAQ Responses Regarding Arsenic in Food Containing Organic Brown Rice Syrup (2012). Available at: https://sites.dartmouth.edu/toxmetal/files/2019/02/arsenicinfoodfaq-1iwt1tb.pdf (23 February 2013)
  7. Arsenic Uptake, Transport, and Accumulation in Plants. Available at: https://sites.dartmouth.edu/toxmetal/research-projects/arsenic-uptake-transport-and-storage-in-plants/ (23 February 2013)