Chromium-6, the Erin Brockovich Chemical, Found in Tap Water of Millions in the US - Polidicks

[QUOTE]Dangerous levels of chromium-6 are contaminating tap water consumed by [B]hundreds of millions of Americans[/B], according to a national report released Tuesday. Chromium-6 is the carcinogenic chemical that was featured in the popular 2000 movie "Erin Brockovich," starring Julia Roberts as the titular activist. The US Environmental Protection Agency has never set a specific limit for chromium-6 in drinking water. There is scientific uncertainty regarding safe levels of this chemical in drinking water and possible long-term consequences of ingestion. But this new analysis from the Environmental Working Group, an independent advocacy group, examines evidence from water systems throughout the nation and [B]concludes that the tap water of 218 million Americans contains levels of chromium-6 that the group considers dangerous.[/B][/QUOTE] [url]http://www.cnn.com/2016/09/20/health/chromium-6-in-drinking-water/[/url]

Fearmongering. EPA sets a limit of 100 ppb, California sets a limit of 10 ppb. The only place that gets above 1ppb is Saint Louise (1.3 ppb) and Pheonix (7.8 ppb). The EWP cited have arbitrarily set the safe limit as 0.05 ppb by what looks like the linear no-threshold model. [editline]22nd September 2016[/editline] Looking back through the sources I can't find where they pulled 0.05 ppb from. [editline]22nd September 2016[/editline] You've got about zero chance reducing a majority of the US' drinking supply to 0.05 ppb. [editline]22nd September 2016[/editline] Found it. Linear no threshold, calculated backwards from a higher concentration to produce a 1 in 10^6 chance of cancer over an average lifetime. Calculating cancer risk that way is bullshit.

[QUOTE=download;51088402]Fearmongering. EPA sets a limit of 100 ppb, California sets a limit of 10 ppb. The only place that gets above 1ppb is Saint Louise (1.3 ppb) and Pheonix (7.8 ppb). The EWP cited have arbitrarily set the safe limit as 0.05 ppb by what looks like the linear no-threshold model. [editline]22nd September 2016[/editline] Looking back through the sources I can't find where they pulled 0.05 ppb from. [editline]22nd September 2016[/editline] You've got about zero chance reducing a majority of the US' drinking supply to 0.05 ppb.[/QUOTE] [url]https://www.wsscwater.com/water-quality--stewardship/water-quality/hexavalent-chromium-cr-6.html[/url] According to this page, the 0.05 ppb (or .02 for some tests) they were referring to was the minimum detectable level of hexavalent chromium present.

[QUOTE=Zonesylvania;51088412][url]https://www.wsscwater.com/water-quality--stewardship/water-quality/hexavalent-chromium-cr-6.html[/url] According to this page, the 0.05 ppb (or .02 for some tests) they were referring to was the minimum detectable level of hexavalent chromium present.[/QUOTE] 0.02 ppb (saying 0.05 ppb is my mistake) is the number the news article says is a safe limit, so they're calling for it to be undetectable in any water. A practically impossible task.

i doubt anything can cause cancer when the amounts are in the ppb range

[QUOTE=Saturn V;51088458]i doubt anything can cause cancer when the amounts are in the ppb range[/QUOTE] You'd be surprised how something so little can kill you a decade later without showing a single sign.

[QUOTE=Matthew0505;51088494]Not sure what units are being used here but a lethal dose of Po-210 in 1kg of water is about 1 ppb by mass.[/QUOTE] ya but we would have to build a water pipe through a breeder reactor and or kgb facility to pickup that in the drinking water chromium-6 is actually pretty common in nature. this is just like people freeking out over arsenic appearing at natural levels

Chromium six might be carcinogenic but from the CDC article I read it has a pretty short biological half life of about 8 hours, so low concentrations are unlikely to be toxic. The worst carcinogens/toxins are the ones that have no supporting metabolism structure in the body, or that accumulate in different tissues. If you excreted 50% of ingested plutonium after 8 hours it would be much less toxic, but because it accumulates in your body it has many more opportunities to cause damage.

Like anything else you need to consider how something gets into your body when you're talking about toxicity/carcinogenic properties. A good example that comes to mind is snake venom. You can go out and drink snake venom if you're so inclined and the risk of injury is waaaaay lower than if you were to get bit. Cr(VI) isn't something that you want to breathe. Drinking it isn't that big of a deal. High concentrations should be investigated, especially since Cr(VI) is used in anti-corrosives, suggesting that these places have something else going on in their water or in their pipes.