Tuesday, August 19, 2008

How Much Arsenic is in Your Drinking Water?

I recently read a press release from Johns Hopkins about the damage that small amounts of arsenic may cause when it is in your drinking water. When I read some of this new research, I immediately looked further to see exactly what I am drinking. Sure enough, my water here in Sedona contains some arsenic.

Arsenic is a semi-metal element in the periodic table. It is odorless and tasteless. It enters drinking water supplies from natural deposits in the earth or from agricultural and industrial practices. Some of arsenic's effects can include thickening and discoloration of the skin, stomach pain, nausea, vomiting; diarrhea; numbness in the hands and feet, partial paralysis, and even blindness. Arsenic has been linked to cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate.

The EPA has set the arsenic standard for drinking water at 10 parts per billion to protect consumers served by public water systems from the effects of long-term, chronic exposure to arsenic. Still, many public water systems flirt with these numbers and even this trace amount can be dangerous.

Take the example from Johns Hopkins, Bloomberg School of Public Health, which has found that arsenic may increase the risk of developing type 2 diabetes. The study found that individuals with diabetes had higher levels of arsenic in the urine compared to individuals without diabetes. The results are published in the August 20, 2008, issue of JAMA.

“Our findings suggest that low levels of exposure to inorganic arsenic may play a role in diabetes,” said Ana Navas-Acien, MD, PhD, lead author of the study and assistant professor. “While prospective studies are needed to establish whether this association is causal, these findings add to the existing concerns about the long-term health consequences of low and moderate exposure to inorganic arsenic.”

Inorganic arsenic is found naturally in rocks and soils. In the U.S., most exposure to inorganic arsenic comes from contaminated drinking water. Foods such as flour and rice can also provide small quantities of inorganic arsenic, particularly if grown or cooked in areas with arsenic contamination in soil or water.

Researchers examined randomly selected urine samples taken from 788 U.S. adults 20 years or older that participated in a 2003—2004 National Health and Nutrition Examination Survey. The results were adjusted for diabetes risk factors, including body mass index and for organic arsenic compounds found in seafood.

Areas where the concentration of inorganic arsenic in the public water supply exceeds those EPA standards include the West, Midwest and Northeast regions. Dietary intake of inorganic arsenic in the U.S. ranges from 8.4 to 14 micrograms per day for various age groups.


1 comment:

Anonymous said...

Another study from Toxicol Appl Pharmacol. 2008 May 29: (Arsenite reduces insulin secretion in rat pancreatic beta-cells...) "An increase in the prevalence of type 2 diabetes has been consistently observed among residents of high arsenic exposure areas. We have previously shown that in rat pancreatic beta-cells, low arsenite doses impair the secretion of insulin without altering its synthesis."