Discussion:

1. Discussion: I found that many authors do not believe that chromium-6 via oral exposure causes cancer. But from material I found via the Purdue Libraries, I found out that hexavalent chromium can be reduced to trivalent chromium in the acidity of the stomach. Trivalent chromium is an essential element therefore not carcinogenic. I also found out that not all of the hexavalent chromium taken in orally is not reduced. The article I found on Purdue Libraries from the Journal of Environmental Science and Health, says that an experiment done on oral exposure with chromium-6 over a lifetime showed more stomach tumors than the control group. Finally that same article also indicates that chromium-6 causes DNA damage in cells. Conclusions: Chromium-6 was not known to be a carcinogen with oral exposure until recent research revealed the damage done to DNA when ingested orally. There are many different opinions on the appropriate levels at which chromium-6 should be present. Along with this is the controversy of the cost of removing and testing for the chemical in drinking water. Dangers of Chromium-6 in Tap Water Introduction: Chromium-6 is commonly used in the industry as a dye or coating for different types of metals. The main public health issue with this is when the known carcinogenic chemical is released into the water that is later used as drinking water. According to a The New York Times article published on Dec 20, 2010, in 25 of the 35 U.S. cities where tap water supplies were tested for hexavalent chromium and found to likely cause cancer in humans in a U.S EPA draft review this year. Methods: I selected this topic because the public has a right to know if something in their own water is causing them to develop cancer. First I looked at recent articles on the USA today and NY Times websites. Then I researched through the Purdue Library system. Finally I looked over all my research and began making conclusions about the topic of the dangers of chromium-6 Anna Cummings HSCI 201, 2011 This image was used from a livestrong.com article, What are the Dangers of Hexavalent Chromium? This picture shows the pollution of chromium-6 that came from an industrial dump of the chemical from a factory. While typically this not what you would see coming out of a kitchen faucet, it is possible the drinking water contaminated will have a bad taste to it. Results: Hexavalent chromium (chromium-6) can be reduced to the essential element trivalent chromium. It is now also known that this does not happen with all of the chromium-6 that is ingested orally. That leftover chromium-6 is then absorbed by cells in the body very readily. This chemical once in cells causes severe DNA damage which likely gives it the carcinogenic characteristic. From several articles it seems that this is a national struggle to figure out what levels of chromium-6 are safe for drinking water. The other struggle is how to regulate the excess once a level is set by the EPA. And the last struggle is coming up with a way to test for this chemical. According to The New York Times article, Weighing the Risk of a Chemical in Tap Water, California would like to limit chromium-6 to 0.06ppb. However, the federal standard for arsenic is 10ppb. This data was obtained from the article found via Purdue Libraries from the Journal of Environmental and Health Sciences. According to the article the data was obtained from a village in China in which there was hexavalent chromium in their water wells. According to the graph on page 173 of the article the data that are the most significant are those for the stomach and lung. This gives us reason to believe that chromium-6 does causes cancer when ingested orally. McClure, Susan T. Sept 2010. What Are the Dangers of Hexavalent Chromium? Retrieved from www.livestrong.com. Retrieved date April 4, 2011. Beaumont J, Howd R, Krowech G, McDonald T, Reynolds S, and Sedman R. 2006. Journal of Environmenal Science and Health Part C, 24:155-182. Review of the Evidence Regarding Carcinogenicity of Hexavalent Chromium in Drinking Water. Retrieved date April 1, 2011. Rudolf, John C. Dec 2010. The New York Times. Weighing the Risks of a Chemical in Tap Water. Retrieved from www.nytimes.com. Retrieved date April 1, 2011. Schor, Elana. Dec 2010. The New York Times. Probable Carcinogen Found in Tap Water of 31 U.S. Cities. Retrieved from www.nytimes.com. Retrieved date April 1, 2011.