Talk:Hexavalent chromium

Confusion between the article and the talk page (title added)

The last edit should have been added to the discussion page instead of to the article itself, I suspect. —The preceding unsigned comment was added by Mq@maq.org (talk • contribs) .

I agree —The preceding unsigned comment was added by 212.138.47.14 (talk • contribs) .

Chromium in alloys is not hexavalent (title added)

Per my discussion with stainless steel suppliers who are involved in the European Directive for the reduction of hazardous substances, hexavalent chromium is NOT present in chromium-containing metals. There is chromium in these alloys, but it is NOT hexavaent chromium, therefore d) above is false.

This statement above was removed from the article owing to its style. Can anyone confirm its accuracy - if so, please edit the article to reflect that. Aussie Alchemist 23:25, 16 January 2006 (UTC)

According to Patty (4th Edition) hexavalent chromium particles are generated in the welding of stainless steel. The discussion in Patty mentions several studies of exposure to hexavalent chromium from these activities. It may be that hexavalent chromium is not present in the metal (as aserted by the stainless steel suppliers referenced above), but is produced from chromium of another valence during the welding process. Pzavon 03:26, 1 March 2006 (UTC) The atoms in a metal alloy usually exist in a low oxidation state, normally zero. Metals are normally oxidised on their surface in air. Stainless steel normally has a adherent coating of chromium (III) oxide on its surface, which is why it is stainless. Normal steel has a loose layer of Iron (III) oxides and hydroxides on its surface, which is why it rusts. When stainless steel is welded, it is possible that further oxidation to Chromium (VI) could occur at the high tempertures used. 2corner (talk) 10:04, 22 August 2008 (UTC)

While I won't attempt to comment on the chemical composition of the alloys, hex chrome sampling is almost always performed during welding fume sampling, especially for stainless welding. [Not logged in] —Preceding unsigned comment added by 75.164.116.78 (talk) 18:32, 5 September 2008 (UTC)

Carcinogenicity (title added)

"Some hexavalent chromium compounds are carcinogens."

I thought all hexavalent chromium compounds were carcinogenic. Should this be fixed? --71.227.190.111 03:48, 16 July 2006 (UTC)

Got a source? —Keenan Pepper 04:12, 16 July 2006 (UTC)

Never mind, I found a good one. —Keenan Pepper 04:46, 16 July 2006 (UTC)

It is disputed among experts whether or not ingested chromium VI is toxic. Probably more to the point, how much is necessary to cause injury. The EPA does have the 0.10 mg/L standard, but that does not mean that it is toxic at that level. That is just the level that they know is safe. I'm not sure it matters, but the way the article is written, it states as a fact that chromium causes cancer. In my reading, this is still a debated question. For example, see http://www.ead.anl.gov/pub/doc/chromium.pdf RyanGentry (talk) 01:56, 26 January 2009 (UTC)

The current source being used for the claim that it's carcinogenic in groundwater links to something that only gives the abstract (for free). The abstract doesn't make the distinction of being carcinogenic in groundwater (and proving even that much isn't the goal of the research anyways). Can a better source be found? One that can actually be, um, verified? (I shouldn't have to pay just to see if a wikipedia reference is valid) 209.90.133.67 (talk) 16:59, 19 May 2009 (UTC)

Detection?

Are there any methods to dectect hexavalent chromium in air or water and are they easy to carry out, or do you need your own lab?(Wouse101 22:26, 24 April 2007 (UTC))

All such methods require laboratory analysis. You don't need your own lab because there are commercial labs that will do the analysis for a fee. Sample collection, in air, at least, requires somewhat specialized collection filters that must be shipped promptly to the lab and must be analysed within a few days. Pzavon 01:37, 25 April 2007 (UTC)

The preferred method for occupational air sampling in the US is OSHA ID-215, requiring a sampling pump and PVC chloride filters (5.0 um pore size, 37-millimeter cassette size, 2-piece). Pzavon is right about the time requirements for analysis. [Not logged in] —Preceding unsigned comment added by 75.164.116.78 (talk) 18:26, 5 September 2008 (UTC)

Besides the OSHA method cited above, other suitable methods are also available for the determination of Cr(VI) in workplace air samples. This includes those methods published by the National Institute for Occupational Safety and Health (NIOSH) in the NIOSH Manual of Analytical Methods (www.cdc.gov/niosh/nmam). Beyond the US, other equivalent procedures have been promulgated by, notably, European occupational health institutes (e.g., in the United Kingdom, France & Germany). Voluntary consensus standard methods for Cr(VI) sampling and analysis have been published by ASTM International (www.astm.org) and the International Organization for Standardization (www.iso.org). For a comprehensive review, see K. Ashley, A. M. Howe, M. Demange and O. Nygren, "Sampling and analysis considerations for the determination of hexavalent chromium in workplace air", J. Environ. Monit. 5: 707-716 (2003). —Preceding unsigned comment added by 158.111.5.34 (talk) 20:52, 4 February 2009 (UTC)

Indiana National Guard v KBG addition

New York Times reported that members of the Oregon National Guard were sent letters advising them of possible exposure from KBG contractors. I added this to the Indiana National Guard v KBG section as this seemed the most relevant location. I added the references to the article. If formatting is incorrect feel free to fix. Also there was no writer attributed to the article other then the Associated Press. Finally, we may need to change the title of the section. I did not want to make too many changes without first posting here. —Preceding unsigned comment added by 161.6.65.56 (talk) 14:59, 12 February 2009 (UTC)

Yes, I fixed the citation formatting. When done correctly it automatically shows in the References Section and should not also be manually placed in the External Links Section. Pzavon (talk) 01:38, 13 February 2009 (UTC)

Americans especially seem to like adding news stories to articles on chemicals. Aside from appearing parochial (it's in my backyard so you better be interested...), these reports raise the question of notability. Wikipedia is probably not the ideal forum for listing incidents, except those of historic significance. Some editors, well intentioned ones, seem to view Wikipedia as a mechanism to alert the populace about pollution incidents. And my guess is that this alerting mechanism is not a sustainable (there are too many incidents) or appropriate for Wikipedia.--Smokefoot (talk) 14:07, 13 February 2009 (UTC)

Your observations make sense to me. What conclusion would you reach? Shout the ING section be removed? Pzavon (talk) 01:36, 14 February 2009 (UTC)

US EPA MCL For Cr VI

The US EPA does not currently have an MCL for Cr VI, only total Cr. The 0.1 ppm is Cr mentioned in the article is for total Cr. I have edited the article to reflect this. —Preceding unsigned comment added by 199.115.12.254 (talk) 15:41, 20 December 2010 (UTC)

Need a real writer here!

This article as written, is crap!

"A controversial study claimed that from 1996 to 2008, 196 cancers were identified among residents of the census tract that includes Hinkley — a slightly lower number than the 224 cancers that would have been expected given its demographic characteristics.[8][9] 196 cases over 12 years for a population of 1915 equates to roughly 853 cases per 100k population per year. By comparison San Bernadino County averaged 359/100k/yr over the same period.[10]"

Hey, I'm no genius, but 1996 to 2008, wait, let me count with my fingers here, is 14 and not 12 years. Also the comparison is reversed: 853cases per 100K/yr is MORE THAN TWICE the 359 cases/100K pop/yr, so how does this relate to the number of cancers being LOWER than expected, Come'on!

Wikipedia's "writers" continue: "Average Cr(VI) levels in Hinkley were recorded as 1.19 ppb with a peak of 3.09 ppb. The PG&E Topock Compressor Station averaged 7.8ppb and peaked at 31.8ppb.[11] Compare to the California proposed health goal of 0.06 ppb. The same day the study came out, the plume of contaminated water was reported to be spreading.[12] Ongoing cleanup documentation is maintained at California EPA's page. Cr(VI) contaminated water supply is apparently a widespread problem and not isolated to Hinkley.[13]

Again, I am no genius, but I know that "Average...levels" don't mean a thing unless you specify the basis of the average: Were these the average of tests on separate instances at one location? Were they the average of several samples the same day at one location? Were they the average of separate locations? And who cares about the "PG&E Topock Compressor Station"? The reader does not know what that is and there is no context! The ppb levels listed are not provided with a base, typically mass/volume, volume/volume, or mass/mass.

It's not enough to quote something and paste it here. If you don't understand and can write it in plain language, then you're not doing any service! Please provide the link as references at the bottom so at least someone that understand technical writing can benefit from the original reference!

"the plume...was spreading"? The "writer" has not provided any context! What plume? If we're expected to look at the references, then why not just provide a link to the story?

And for the record, it is true that stainless is manufactured without hexavalent chromium, but according to OSHA, it may be generated by oxidation from other forms of chromium during hot work, hence the hazard.

We don't need to know every place in the world where the've found hexavalent chromium. How is that relevant to the theme? Instead the article is lacking in the more central issue of the real debate as to toxicity, permissible levels, political issues, international actions on the substance, legal activity, and comments on the possibility of finding substitutes for the uses of hexavalent chromium. —Preceding unsigned comment added by 146.23.68.40 (talk) 22:45, 12 January 2011 (UTC)

References Additions

Suggest adding as an external link "http://water.epa.gov/drink/info/chromium/guidance.cfm". this is the USEPA's page for hexavalent chromium in drinking water. the EWG article which precipitated much of the current concern would be found at; http://www.ewg.org/chromium6-in-tap-water.

Studies, Original Drinking MCL and Current Concerns

When the USEPA was originally evaluating regulating the level of chromium in drinking water, it was assumed that via ingestion, and hexavalent chromium would be converted to trivalent chromium by stomach acids. Due to this the regulation was based upon trivalent chromium, which at higher concentrations has been shown to cause skin conditions. Based upon this data, the drinking water limit was set to 100 ug/L. More recently, concerns have arisen that individuals under medication reducing stomach acids would be particularly at risk to hexavalent chromium exposure.

Hexavalent Chromium MCL

California is proposing 0.06 ug/L. I believe the USEPA is considering 0.1 ug/L at this time but given the current public concern over the chemical this may end up at the California limit.

Gpronger (talk) 23:22, 15 March 2011 (UTC)Greg Pronger