Re: [math-fun] 177 million tons of ice???
Henry Baker> What makes D2O toxic? I wondered too! Excerpts from the top 2 Google results for "heavy water toxicity" are below. -- Mike ------------------------------------------------
If I recall correctly, there was an experiment done some years ago with mice and deuterium. The mice were fed normal food, but given pure deuterium instead of, "water". As I remember, the mice died of dehydration. The cells were unable to use the deuterium.
Not the kind of dehydration you're probably thinking of, though. When body deuterium reaches about 50%, it inhibits mitosis because spindle microtubules won't form (some hydrogen bond effect inhibiting self-polymerization, I think). So all eucaryotic cells are poisoned at about these concentrations, or a little higher (bacteria can survive full deuteration -- they just grow half as fast). The consequences of failure of cell division for an intact animal like a rodent, are somewhat like those of radiation or chemo -- the bone marrow and gut lining cells suffer. Animals die of infection or diarrhea. That might make a good cerebral mystery for a student text: a person with full control of an elderly relative deuterates them to death over a couple of weeks to a month (which would take about 50 kg of heavy water at $300 a kg, but nevermind). Forensics thinks the person died of some strange disease or poison, but can't identify one (since they don't routinely do any tests to identify D!). The detective only recognizes something's amiss when the bad guy offers him ice in his lemonade, and has forgotten to dump the ice in the icebox, which is made from heavy water. Detective notices the ice SINKS in his glass. Hmmmm. Steve Harris, M.D. ------------------------------------------------ Despite the fact the light water and heavy water are chemically identical, heavy water is mildly toxic. How can this be? Since heavy water is heavier than normal water, the speed of chemical reactions involving it is altered somewhat, as is the strength of some types of bonds it forms. This affects certain cellular processes, notably mitosis, or cell division, due to the difference in binding energy in the hydrogen bonds needed to make certain proteins. Mouse studies have shown that drinking only heavy water along with normal feed eventually causes degeneration of tissues that need to replenish themselves frequently, and leads to cumulative damage from injuries that don't heal as quickly. One study likens the effects to those suffered by chemotherapy patients. Heavy water toxicity manifests itself when about 50% of the water in the body has been replaced by D2O. Prolonged heavy water consumption can cause death. Don't get any funny ideas about using heavy water as a virtually untraceable and undetectable murder weapon, though. Given its role in breeder reactors for producing weapons-grade plutonium, production and distribution of heavy water is closely monitored and controlled. Obtaining a significant amount is damn near impossible for the average Joe, and you'd need a LOT of it to kill anyone. It's also expensive--one estimate puts the price at about $300 per kilogram. Hit 'em over the head with a bottle of Poland Spring and save yourself some grief. --SDSTAFF Q.E.D. Straight Dope Science Advisory Board
So is this what Yassar Arafat died from? Michael D Beeler wrote:
Henry Baker> What makes D2O toxic?
I wondered too! Excerpts from the top 2 Google results for "heavy water toxicity" are below.
-- Mike
------------------------------------------------
If I recall correctly, there was an experiment done some years ago with mice and deuterium. The mice were fed normal food, but given pure deuterium instead of, "water". As I remember, the mice died of dehydration. The cells were unable to use the deuterium.
Not the kind of dehydration you're probably thinking of, though. When body deuterium reaches about 50%, it inhibits mitosis because spindle microtubules won't form (some hydrogen bond effect inhibiting self-polymerization, I think). So all eucaryotic cells are poisoned at about these concentrations, or a little higher (bacteria can survive full deuteration -- they just grow half as fast). The consequences of failure of cell division for an intact animal like a rodent, are somewhat like those of radiation or chemo -- the bone marrow and gut lining cells suffer. Animals die of infection or diarrhea.
That might make a good cerebral mystery for a student text: a person with full control of an elderly relative deuterates them to death over a couple of weeks to a month (which would take about 50 kg of heavy water at $300 a kg, but nevermind). Forensics thinks the person died of some strange disease or poison, but can't identify one (since they don't routinely do any tests to identify D!). The detective only recognizes something's amiss when the bad guy offers him ice in his lemonade, and has forgotten to dump the ice in the icebox, which is made from heavy water. Detective notices the ice SINKS in his glass. Hmmmm.
Steve Harris, M.D.
------------------------------------------------ Despite the fact the light water and heavy water are chemically identical, heavy water is mildly toxic. How can this be? Since heavy water is heavier than normal water, the speed of chemical reactions involving it is altered somewhat, as is the strength of some types of bonds it forms. This affects certain cellular processes, notably mitosis, or cell division, due to the difference in binding energy in the hydrogen bonds needed to make certain proteins. Mouse studies have shown that drinking only heavy water along with normal feed eventually causes degeneration of tissues that need to replenish themselves frequently, and leads to cumulative damage from injuries that don't heal as quickly. One study likens the effects to those suffered by chemotherapy patients. Heavy water toxicity manifests itself when about 50% of the water in the body has been replaced by D2O. Prolonged heavy water consumption can cause death.
Don't get any funny ideas about using heavy water as a virtually untraceable and undetectable murder weapon, though. Given its role in breeder reactors for producing weapons-grade plutonium, production and distribution of heavy water is closely monitored and controlled. Obtaining a significant amount is damn near impossible for the average Joe, and you'd need a LOT of it to kill anyone. It's also expensive--one estimate puts the price at about $300 per kilogram. Hit 'em over the head with a bottle of Poland Spring and save yourself some grief.
--SDSTAFF Q.E.D. Straight Dope Science Advisory Board
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Given the routine use of mass spec as a detector for drug molecules in forensics, D2O poisoning would be completely, trivially obvious. On Sep 23, 2005, at 9:25 AM, Michael D Beeler wrote:
Henry Baker> What makes D2O toxic?
I wondered too! Excerpts from the top 2 Google results for "heavy water toxicity" are below.
-- Mike
------------------------------------------------
If I recall correctly, there was an experiment done some years ago with mice and deuterium. The mice were fed normal food, but given pure deuterium instead of, "water". As I remember, the mice died of dehydration. The cells were unable to use the deuterium.
Not the kind of dehydration you're probably thinking of, though. When body deuterium reaches about 50%, it inhibits mitosis because spindle microtubules won't form (some hydrogen bond effect inhibiting self-polymerization, I think). So all eucaryotic cells are poisoned at about these concentrations, or a little higher (bacteria can survive full deuteration -- they just grow half as fast). The consequences of failure of cell division for an intact animal like a rodent, are somewhat like those of radiation or chemo -- the bone marrow and gut lining cells suffer. Animals die of infection or diarrhea.
That might make a good cerebral mystery for a student text: a person with full control of an elderly relative deuterates them to death over a couple of weeks to a month (which would take about 50 kg of heavy water at $300 a kg, but nevermind). Forensics thinks the person died of some strange disease or poison, but can't identify one (since they don't routinely do any tests to identify D!). The detective only recognizes something's amiss when the bad guy offers him ice in his lemonade, and has forgotten to dump the ice in the icebox, which is made from heavy water. Detective notices the ice SINKS in his glass. Hmmmm.
Steve Harris, M.D.
------------------------------------------------ Despite the fact the light water and heavy water are chemically identical, heavy water is mildly toxic. How can this be? Since heavy water is heavier than normal water, the speed of chemical reactions involving it is altered somewhat, as is the strength of some types of bonds it forms. This affects certain cellular processes, notably mitosis, or cell division, due to the difference in binding energy in the hydrogen bonds needed to make certain proteins. Mouse studies have shown that drinking only heavy water along with normal feed eventually causes degeneration of tissues that need to replenish themselves frequently, and leads to cumulative damage from injuries that don't heal as quickly. One study likens the effects to those suffered by chemotherapy patients. Heavy water toxicity manifests itself when about 50% of the water in the body has been replaced by D2O. Prolonged heavy water consumption can cause death.
Don't get any funny ideas about using heavy water as a virtually untraceable and undetectable murder weapon, though. Given its role in breeder reactors for producing weapons-grade plutonium, production and distribution of heavy water is closely monitored and controlled. Obtaining a significant amount is damn near impossible for the average Joe, and you'd need a LOT of it to kill anyone. It's also expensive--one estimate puts the price at about $300 per kilogram. Hit 'em over the head with a bottle of Poland Spring and save yourself some grief.
--SDSTAFF Q.E.D. Straight Dope Science Advisory Board
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