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Glom
2005-Dec-22, 12:40 PM
I need an example of nasty chemical waste that remains a permanent hazard. I refer to this stuff when pointing out that nuclear waste is time limited but it would be more effective if I had a specific example of two.

What are some particularly effective examples?

Swift
2005-Dec-22, 02:31 PM
I guess it depends on what you mean by "permanent". There are some really nasty chemicals, but given enough energy and equipment, you can make them benign. So for example, even nerve gas can be either incinerated or chemically neutralized (wkipediai/VX (http://en.wikipedia.org/wiki/VX)), but it takes a lot of effort to do so. Similarly, some of the toxic metals and their compounds (mercury, lead) are nasty in all of their forms, but some forms (soluable salts, organo-metallic compounds) are worse than others, since they either are easier to disperse in the environment or easier to be absorbed by organisms. The best you can do there is put them in as inert a form as possible.

Some of the worst stuff is mixtures, usually as stored chemical waste. Some of the US EPA Superfund's worst sites are old toxic waste dumps where just about anything was just dumped into holes in the ground. So you have toxic inorganic compounds, solvents, etc., all mixed together. Neutralizing this mixture is tough, because the step you might use to neutralize one thing, makes something else worse. Usually you have to try to do some separations first.

Hugh Jass
2005-Dec-23, 01:38 AM
I agree with swift, define permanent. Lots and lots of things will be around for several generations, but may not be “permanent” most, if not all toxins aren’t “permanent”.
Lead and Mercury are great examples they stick around for a LONG time some forms of the metals are more toxic than others. PCBs and generally Chlorinated-hydrocarbons are bad with very long life spans. Hydrocarbons in general when they get into the wrong water are in and of themselves pretty bad, but their components and many of their breakdown products like polynuclear aromatic hydrocarbons lengthen the amount of time there is danger. There are a handful of other chemicals out there that have pretty long life spans, I can’t think of right off hand.

Van Rijn
2005-Dec-23, 01:45 AM
Arsenic and some arsenic compounds are quite nasty. There are definitely chemical toxins that are worse, but do they stick around as long?

LurchGS
2005-Dec-23, 02:26 AM
heavy metal toxins will last a day or two... I think Dioxin is gonna be around for the superbowl, too..

http://www.ejnet.org/dioxin/

----

I'll see your invisible elf and raise you a ghost and a hobbit

sarongsong
2005-Dec-23, 07:57 AM
Katrina fall-out:
Mounds of Toxic Waste Vie for Attention (http://www.nytimes.com/2005/12/20/science/20clea.html)---NY Times

Swift
2005-Dec-23, 02:44 PM
heavy metal toxins will last a day or two... I think Dioxin is gonna be around for the superbowl, too..

http://www.ejnet.org/dioxin/

:confused:
Dioxin is nasty stuff. But I don't understand your comment about heavy metal toxins will only last a day or two. Mercury and lead will last pretty close to forever in some form. Now a sheet of lead metal is pretty benign, because it is relatively inert chemically. But lead has not been put in gasoline for decades in the US, yet you can still find measurable quantities of lead dust and compounds in roadside soils (CDC reference (http://www.cdc.gov/nceh/lead/publications/books/plpyc/chapter3.htm#Soil and Dust)). In the form of dust (inhalation hazard) and organo-lead compounds it is still very dangerous, particularly for children.

mid
2005-Dec-23, 04:27 PM
"will last a day or two" - I think Lurch was going for understatement.

Relmuis
2005-Dec-23, 04:31 PM
Lead has an appreciable vapour pressure at room temperature, which is why all lead pipes etc. must be covered in paint.

Hugh Jass
2005-Dec-23, 06:25 PM
heavy metal toxins will last a day or two... I think Dioxin is gonna be around for the superbowl, too..

Dioxin falls under my previous statement of "chlorinated-hydrocarbons". Like I said it depends on how much time your talking about. Most everything if left up to natural remediation will breakdown and "clean" itself up, but most everything will also stick around in nasty form for at least a couple generations.

Arsenic is bad míkay, but it doesnít last as long as the others mentioned, it remains bad for a generations, but not anywhere near forever. As well PDBs are in the news recently, they donít seem to last as long as PCBs but could be just as bad, and they are EVERYWHERE. Loads of other heavy metals, name one its there and bad and will last for a long time, but lead and mercury are just the most prevalent. Pesticides and Herbicides, most break down pretty quickly but they can be bad while theyíre around. All kinds of chlorinated solvents like benzene, PCE, TCE, Carbon Tetrachloride.
Asbestos is pretty much forever, it is in native form scraped off of rocks on the side of a trail just as bad as after it has been processed and put into insulation or something similar.

Glom
2005-Dec-24, 02:08 PM
Unreprocessed spent fuel will take just under 10,000 years to decay to below the activity of the original uranium ore (although vitrified fission products, the true waste, will do so within 600). Is there any chemical materials that last that long? If not, it kind of invalidates my point about the limited lifetime of HLW being an asset.

Relmuis
2005-Dec-24, 04:31 PM
Prions (from mad cow disease or BSE) in the soil may last for decades. If dung from mad cows is used as a garden fertilizer, prions will become airborne, and, when inhaled through the nose, can enter the brain within minutes, causing Creutzfeld-Jacob Disease. Carleton Gajdusek calls this reverse axonal transport. Prions survive all desinfectants and temperatures up to 360 degrees centigrade. Scalpels and such which may be infected with prions are treated much like radioactive waste.

Hugh Jass
2005-Dec-24, 10:03 PM
Now that's a little beyond off the top of my head knowledge. Radioactive wastes by definition decay at a set rate. There is little that can be done to significantly change the overall time line of the process. Most chemical wastes are subject to any number of factors that can affect not only the rate at which they break down, but also how benign the breakdown products might be. In natural environments, the pH, O2 concentrations, concentration of other chemicals, or inorganic salts, temperature, certain bacteria, all have some influence. The concerns are usually immediate impacts on populated or to be populated environments, 100’s of years is significant, I don’t know of anything that would be expected to be an issue for thousands.

On a bit of a side note, I’ve done environmental sampling, and analytical laboratory testing of soil and water at/from a class 1 hazardous waste landfill. The two items that concerned me the most were a)the potential for free cyanide where it wasn’t expected but possibly existed, and b)radioactive waste that wasn’t supposed to have ever been accepted. Our personal protective equipment was absolutely not sufficient to deal with anything radioactive. Situations like that do lend to the extreme stereotyping of radioactive materials.

sarongsong
2006-Mar-02, 08:15 AM
I need an example of nasty chemical waste that remains a permanent hazard...What are some particularly effective examples?Unsure of its shelf-life, but an undoubtedly nasty example:
March 3, 2006
"...Tests conducted on 230 [soft] drinks on sale in Britain and France have identified high levels [up to 8X drinking-water limit] of benzene...At present, the drinks’ identities have not been revealed..."
Times Online (http://www.timesonline.co.uk/article/0,,2-2065539,00.html)

01101001
2006-Mar-02, 08:42 AM
"...Tests conducted on 230 [soft] drinks on sale in Britain and France have identified high levels [up to 8X drinking-water limit] of benzene...At present, the drinksí identities have not been revealed..."
Heh. Only 1.6 times the US EPA drinking-water limit.

sarongsong
2006-Apr-01, 03:33 AM
Update...
April 1, 2006
"Soft drinks were being removed from [British] supermarket shelves last night...The FSA rushed out results yesterday of tests on 149 drinks..." TimesOnline (http://www.timesonline.co.uk/article/0,,2-2113695,00.html)

Lord Jubjub
2006-Apr-01, 10:40 PM
Is arsenic toxic as a pure element? or is it similar to lead? I always thought that mercury was toxic even as a pure element.

How stable is the cyanide ion?