Dartmouth Researchers Evaluate Rice as a Source of Fetal Arsenic Exposure

[OKIsItJustMe]

http://now.dartmouth.edu/2011/12/dartmouth-researchers-evaluate-rice-as-a-source-of-fetal-arsenic-exposure/

Dartmouth Researchers Evaluate Rice as a Source of Fetal Arsenic Exposure

Posted on December 5, 2011 By Joseph Blumberg

A study just published by a Dartmouth team of scientists in the Proceedings of the National Academy of Sciences (PNAS) advances our understanding of the sources of human exposure to arsenic and focuses attention on the potential for consuming harmful levels of arsenic via rice.

…

“The study presented in the PNAS paper is based upon a sample of 229 pregnant New Hampshire women whose urine was tested for arsenic concentration,” says Diane Gilbert-Diamond ’98, a postdoctoral fellow and co-lead author on the paper. The women in the study were divided into two groups based on whether or not they had eaten rice in the two days before urine collection. The tap water in their homes also was tested for arsenic concentration.

“This enabled our team to separate the potential for exposure to arsenic from drinking water from that of rice,” says Gilbert-Diamond. The urinary arsenic analyses were performed at the University of Arizona by co-author Professor A. Jay Gandolfi and colleagues and water testing was performed at Dartmouth’s Trace Element Analysis Facility by co-author Brian Jackson, PhD.

…

Urinary arsenic concentrations for the 73 study subjects who ate rice showed a median of 5.27 micrograms per liter, while the median for the 156 non-rice eaters showed 3.38 micrograms per liter, a statistically significant difference between the two groups.

…

http://www.pnas.org/search?submit=yes&doi=10.1073%2Fpnas.1109127108

[MADem]

1. This is an interesting report....not good news for the southern rice industry, though.

The large variability in arsenic in different rice strains leads to
considerable uncertainty in estimated exposures for a given mass
of consumed rice. Both the concentration and speciation of arsenic in rice vary with rice cultivar and the arsenic content of the
agricultural soil (16, 17). For example, Williams et al. (17) found
that rice grown in the south-central United States had a substantially higher average total arsenic concentration than rice
grown in California (0.30 vs. 0.17 μg As/g rice). The percentage
of arsenic in rice that is in inorganic forms also has been shown
to vary substantially (21); one study reported rice samples that
ranged from 27 to 86% inorganic arsenic, with the remainder
largely composed of DMA (16). This same study found that the
arsenic in rice grown in the United States was predominantly
DMA, with 42% of the arsenic in inorganic forms (16). Although
inorganic arsenic is thought to be more harmful than DMA (31),
further epidemiological studies are needed to better understand
the health risks of DMA, which is a demonstrated carcinogen in
rats (32). ....