would be cool if you could shoot purified water with a gamma gun to irradiate it.

Great idea!

I would settle for an in game canteen so I could manually fill it from any water source.

Admittedly, I did find it humorous as well. I should, however, add that there did seem to be small scale purifiers in Fallout 3, such as in Rivet City. Rivet City did need purified water for its hydroponics operation. Also, John Henry Eden mentioned small scale purifiers on the radio. I feel as if others were mentioned, but cannot recall where.

I am fairly certain that dirty water is not simply dirty in the sense of being radioactive (neutron activated), but is actually dirty (filled with sediment tainted with fallout).

Indeed clean water can become radioactive only by neutron activation. It's not easy to do it (exposing it to gamma rays probably wouldn't suffice) and such water stays radioactive only for few days.

It's other elements inside the water (for example Celsium) which made it "dirty" in radioactive sense.

This is one of the first things I will modding into my game.

Yeah and with all that mutated animal life running around atom only knows whats in that water.

The way radiation is handled in Fallout games is one of my pet-peeves, but I've just learned to deal with it.

I am not a nuclear scientist, but I play one on the Internet, so . . . come amble with me a bit and listen to my kidney stones of wisdom . . .

Most of the nuclear weapons that have been developed and used by the major World Powers in our universe produce quite minimal fallout. This is because they are designed to produce optimum destructive force, and that means expending most of the fissile material, thus leaving behind non-fissile material. The other factor is that, generally these devices arrive by airborne delivery system, and are set to detonate at some considerable height above their target, 300 meters or greater. I believe the purpose here is to expose the largest possible area of the target area to the blast of the detonation.

As a result of these two factors, Hiroshima and Nagasaki had relatively normal levels of radiation within a matter of days of the attacks. Most of the radiation sickness and non-fatal injuries that occurred resulted from exposure to the blast itself, but in somewhat protected or at enough distance that it didn't just incinerate the person.

The area of the detonation produces a ball of heat that is as hot as the sun. The heat drops pretty rapidly with distance from the center of the detonation, but even at considerable distance (all depending on the size of the bomb) the heat can still be sufficient to ignite wooden structures or even melt metal objects. There is also a tremendous concussive force that will obliterate most of the structures close to the blast.

Most of the models and projections I've read for the long-term effects of a relatively large regional nuclear war, or for a global one, estimate that most of the environmental damage, and long-term environmental and climatic impact would derive from the fires set as a result of the blasts, not from radiation released from the blasts nor even from the blasts themselves. A large fraction of the INITIAL casualties and property damage would result directly from the blasts themselves, as a result of the weapons targeting major population centers, but the after effects of detonating one or more such large bombs over major population centers in most parts of the world would be massive ring shaped fires igniting in the areas surrounding those population centers. With multiple nearby areas being hit simultaneously, and assuming a relatively high degree of regional saturation of targets, such fires might well extend to the level of whole regions, maybe even whole continents. The earth has not seen this scale of catastrophe for millions of years and if the war was large enough (as it is depicted in game) the fires might well destroy most of the landscape. Instead of a Boston and D.C. that look "relatively" intact but banged up, what would probably be seeing a landscape that is more like the Glowing Sea EVERYWHERE, at least in so far as it all looks burnt to crisp, there are few structures intact, and everything that was open to the surface is burnt. (actually the intent of the designers with the Glowing Sea puzzles me as it appears they are representing something like lava flows having engulfed a lot of the landscape. I don't know if they are implying that the bombs caused volcanism or that the bombs produced such heat that they melted parts of the lanscape, but anyway . . .).

The effect of a global nuclear war on the scale we are presented in game would likely result in massive widlfires engulfing large sections of every continent where there a large number of targets. Some continents might be largely spared these initial effects, but Europe, the U.S., India, China, Russia, Pakistan, probably Israel, and probably other nations which are intended to be "nuclear powers in game" but are not in real life (yet!) would likely be LITERALLY burnt to a crisp. The areas which had ANY surface structures untouched by the fires would most likely be the exception not the rule. Remote areas might well go largely unscathed by the initial fires so the New Vegas area is arguably "realistic" in how it is presented, but literally most of the entire eastern seaboard of the U.S. should realistically be burnt, charred ash and rubble.

The effect of so many fires burning on Earth would likely be a long-term nuclear winter, which would make survival for many species and humanity itself a very close call. No one knows for sure if such a nuclear winter WOULD occur, but it makes sense according to most models and it could last for a long time, maybe forever depending on the underlying natural forces that actually drive climate change.

If the severity of such a nuclear winter was extreme enough, everywhere outside a narrow band in the tropics might well be completely depopulated, indeed, an ice age might well ensue and make large portions of the northern and southern hemisphere largely uninhabitable by humans.

"Neutron bombs," developed in the 1970s produce a terrible radiation burst, but they leave virtually no fallout at all and the area is safe within hours of the detonation. "Dirty bombs" are, as far as I know, largely hypothetical, though I believe that in a couple instances of test bombs detonated during the Cold War, calculations were off and the result was a de facto "dirty bomb." A Dirty Bomb is a bomb that is configured not to use up as much of the fissile material as possible so as to maximum the destructive force of the bomb (heat and shock wave) but rather, to reduce a significant fraction of the fissile material into small particles and extrude a gigantic cloud of those radioactive particles into the landscape. Such a bomb would be most effective if detonated under low barometric, high humidity conditions and at enough height to mix the materials into the atmosphere, else low enough to enshroud an area on the ground.

Based on my understanding of this stuff (and some of what I've quoted here might not be exactly correct, I'm just writing from memory based on little 'research' efforts I've done over the years, but I think I've got the basic jist of it correct, but if not someone who knows better please do correct me . . .) the type of widespread radioactive contamination of (apparently) the entire hydrosphere of the planet which we are presented with in the game is essentially impossible. It may be possible to contaminate a large region, and in fact there are relatively large regions with relatively high levels of contamination (Chernobyl area and at least one large cone shaped area in Siberia where an earlier reactor went critical) but when we say "high" we are not talking about the kinds of levels suggested in the game.

There are scientists who live at Chernobyl for months on end, they even go within meters of the ruined reactor. Yes, they are receiving higher than "ideal" doses of radiation and long-term many of them may suffer health issues as a result of it, but it is not the sort of "You are going to die in a matter of seconds/minutes" thing we are presented with in game when the player enters a highly radioactive zone . . . here we get into the utterly fanciful way "radiation sickness" and radioactive contamination are treated in the game, but then it IS a game so we have to accept that the way "radiation" works in game is just inherently DIFFERENT than in our universe . . . in the real world, one does not "absorb" radiation and then "clean it out" it just doesn't work that way. If you get exposed to radiation, then that is it, you've been exposed and nothing known to science is going to reverse those effects. If the dose was high enough, you are going to die, maybe in a matter of seconds, or maybe in a more prolonged and agonizing way . . . If you ingest something that is contaminated with radioactive material (whether it is molecular or larger), there is no known way short of your metabolic system passing it through to just "flush it out" of your system as depicted in game.

Of course modern medicine makes extensive use of both applied and ingested radioactive material, and I myself have worked with radioactive material in a ligand-assay lab for some years in grad school . . . but we are talking tiny, tiny, TINY doses. One could literally drink a whole 250mL bottle of the tracer stuff I used to work with and barely get as much radiation as eating a crate of bananas. Not a good idea, especially given it was a solution containing potentially biohazardous molecules to which the tracer was attached, but really not particularly health threatening.

People who work in marble buildings like the common governmental structures in Washington D.C. receive substantially more annual radioactive exposure than people who work in other buildings. Bananas (because of the high iodine) content have a much higher level of radioactivity than many other fooods, but again, we are talking about tiny differences that are on the extreme low end of the scale.

Suffice to say, even if we accept that somehow science in Fallout allows for exposure to radiation to be "reversed" and "flushed" as we are presented with Rad-Away, the conditions of the planet don't make sense in terms of modern real world nuclear weapons. Dirty bombs are, as far as I know not considered useful or efficient by any of the nuclear powers and for good reason: they produce much less boom, and much more long-term problem (by virtue of contaminating the area of the detonation). The only entities who might have the capacity to produce such bombs (in the real world) and who would ostensibly see them as an effective and desirable weapons system would be terrorists.

Of course, the situation we are presented with in the timeline leading up to 23 Oct 2077 is one of great strife and desperation and we are presented with more than one instance of attempted Chinese sabotage in the U.S. As a result of deployment of T-51d armored units into China, the situation in 2076 was getting truly http://fallout.wikia.com/wiki/Timeline#1969

This was more than a year before the bombs fell, so IF China had already planned for a "scorched earth" policy early enough in the preceding years of the war (which seems to have never been officially declared, but de facto in effect as early as April 2052) then the explanation we can arrive at for the effective "contamination of apparently the entire planet" with high levels of radiation is that China had a large arsenal of dirty bombs and that these were one of the primary weapons they used.

It seems many of the details of the Atomic phase of the Great War have been intentionally left ambiguous and we do not even know who attacked first for certain (I suspect it was SkyNet myself), so it seems impossible to rule out this possibility.

Even if the Chinese hit U.S. cities with 10,000 dirty bombs, my gut instinct is, the amount of radiation that would release (applying real world physics here) would be completely insufficient to accomplish what is portrayed in the game, i.e., a high level of radioactive contamination in all open water sources on Earth (clouds, rivers, lakes, the oceans) but not in all underground aquifers or other sequestered water sources (e.g., the wells which some Vaults apparently tap into).

Phew! This doesn't really get at the question of "why do little dirty water" but it hopefully puts the physics and environmental contamination issues into some light. In short, its all a bit farfetched, so all bets are off as far as "the availability of dirty water needs to be realistically high."

It makes no damn sense that there is that much "radioactive contaminated water" in the game world in the first place so . . . well there you go.

Indeed, the gamma rays (from the gamma gun) would be insufficient, and would have virtually no discenable effect on purified water. Contamination by radioactve isotopes of various elements commonly found in fallout, or neutron activation of the water itself would be reqiured. The former is probable given that dirty water is likely taken from ponds, lakes, rivers, and streams, which are an area of concentation of these elements, especially in the silt. This silt would would make it dirty, both figuritively and literally.

Well said but, how much radioactive material would need to have been released on 23 Oct 2077 in order to achieve the situation with which we are presented in game: all open-water on Earth is "contaminated" (and aparently neutron activated, not just polluted with radioactive dust/silt).

You sound like someone who might have a better gut instinct of the maths, else an actual desire to do some number crunching. So tell us this, is my gut instinct wrong that, even if every single nuclear bomb ever created in our real world were reconfigured to maximize its fallout, would it even be possible to pollute the entire hydrosphere of Earth at levels approximating those we are presented with in game?

Though I would not mind a full discussion of radiation, this is neither the time (for me right now anyway) nor place, but I do want to add three details in regards to fallout. While true that when a nuclear bomb detonates it does use most of its fissionable core leaving behind little of that element, the reaction also creates radioactive (usually) daughter isotopes. These daughter isotopes are the primary source of radiation in fallout. Furthermore neutron activation of non-radioactive materials is of an additional concern. Lastly the world of Fallout has a great many unattended nuclear reactors (which if they fail, are more irradiating than nukes), engines, and large quantites of nuclear waste (which remains dangerous for thousands of years), all of which continue to leak into the environment. I am not saying that Fallout is perfect in its representation, just that nukes have secondary (daughter isotopes), tertiary (neutron activation), and quaternary (damaged, unattended reactors) effects that lead to more radioactive particles.

Fortunately, we have no real world parrallels, but regardless of the lack of empirical data, I am still fairly certain that the world would still have recovered more (despite the radiation that would still be present) given the tenacity of life. That and the relatively short half-life of most daughter isotopes.

You speak kindly of me, but unfortunately, I cannot answer this. Firstly, I am not a nuclear physicist (sadly), just well read on the topic. Secondly, I think the models necessary to accurately predict this would be quite complicated, given the multitude of complex systems involved (i.e. atmospheric conditions, ocean currents, apocolyptic effects on these). Thirdly, we fortunately have no real world examples to go by, and thus Ithink the best we can do is maybe caculate some levels of radioactive materials via half-lives. I, however, feel that this would be woefully inadequate.

Dual apologies: sorry if I dissapoint; sorry for the slow response as I am typing this on a virtual keyboard.

Addendum:

I would like to answer at least the levels of materials, but I doubt that I will have sufficient time to look up all of the daughter isotopes and neutron activated mateials (which put bluntly is a lot) in question.

I for one would love to hear some of you folks who really are trained in these areas talk more. I'm a biological scientist with very minimal physics training, so what understanding I have has been cobbled together from online research over the years, largely as a result of encountering things in games that made me ask questions.

I hope I didn't kill the discussion with my long post, that was certainly not my goal, and I hope that we get to hear more from you King Stugly and anyone else with good knowledge. I'm happy to be corrected on these things as I consider my knowledge to be imperfect at best and would appreciate getting things clarified.

The old strategy game "The Operational Art of War III" had a scenario in it set in Western Europe in the late 1970s and one of the possible outcomes of the game was a tactical nuclear exchange between invading Soviets and NATO. I was surprised at how seemingly minimally destructive some of the tactical nukes seem to be as presented in the game so I started asking questions on the Matrix site, reading up a bit and quickly realized that, nuclear weapons are not quite so destructive (at least when used in limited numbers) as they are often imagined in popular culture.

I would have a hard time addressing my question above with out help (how much fallout would it take to effectively contaminate the entire hydrosphere to a level we see in game), but I'll give it a whack.

Earth is estimated to have 1,338,000,000 km^3 of water on it, and because it has been many decades after the war, and we see rather highly radioactive water more or less everywhere in the games, that means that effectively enough fallout has been introduced into the Earth to achieve contamination of the entire system. To the extent that this contamination is not derived from ongoing pollution (abandoned reactors and waste sites as you noted King, an issue that didn't even occur to me . . .) and represents the continuing effects of the original nuclear war, those isotopes https://en.wikipedia.org/wiki/List_of_radioactive_isotopes_by_half-life

Because of how radiation works in game, it seems difficult to establish what the https://en.wikipedia.org/wiki/Sievert#ICRP_dose_limits, but I'd guess that . . . when one goes into deep water in game, one is being exposed to the equivalent of about 2 Sv? 1 Sv is the maximum career dosage allowed for NASA astronauts, and ~4 Sv seem to be the lowest fatal doses on record (there is this bizarre story of a guy who was unknowingly exposed to a very large lifetime does by an unethical research study, but I'll have to surf around to find the details . . )

So . . . in game we are presented with a world in which being immersed in any open water source on Earth results in exposure to about 2Sv.

So, all we need to calculate is: how many cubic meters of which isotope would it take to contaminate 1,338,000,000 km^3 to a level that it would still carry a dose of roughly 2 sv on acute exposure to the entire surface of the body. The whole http://www.wolframalpha.com/input/?i=volume+human+body and surface area is about

So I suppose that our calculations would need to take that into account but it wouldn't seem to make a huge difference to the estimate of how much fallout it would take to produce that level of contamination.

I have no idea how many parts per million it would take in water to make it that radioactive so I'd be a a dead-end there myself.

All the half-lifes are in scientific notation, so we need to know how many seconds X 10^n we are talking about with ~210 years.

210 x 365 = 76,650 days

x 24 = 1,839,600 hours

x 60 = 110,376,000 minutes

x 60 = 6,622,560,000 seconds

So, excluding leap years (who needs 'em anyway!?) we are talking about 6.622 x 10^12 seconds having elapsed since the Great War (roughly). Things get really complicated at this point because of the way half-times work, and the fact that, with enough of the isotope, even one with a relatively short half-life could still have enough still present (albeit a very small fraction of the original) to be a contaminant.

I like dirty water. Of course I also like soup and omelets.

I wish that I could be using a keyboard right now.

Anthropoid, you mentioned heading into deep water where the concentration of radioactives would be highest, given that they would sink due to their greater density. On this I should add that while relevant to our total starting radiation, these sequestered particles are no longer relevant to the water to which people have access. Though, as I mentioned before the currents of oceans and the hydrodynamics of any body of water will complicate any attempt to determine the original radioactive release. For example, do we know at what rate the particles would sink? To determine this we have to consider such things as currents, salinity, ice caps, saline cycle (long story), and apocolyptic climate change (unknowable), just to name a few. The amount of particles in the water would in part depend on runoff from surrounding terrain, for which the rate would be difficult to guess as it is influenced by weather patterns we do not know of.

Another area that should not be overlooked is the rate at which the fallout would occur in the apocolyptic atmosphere. This rate very well could very well be quite different than ours, which is understood.

Lastly, yes, the way in which the rads in game function does make it rather difficult to coorelate it to reality (in reality as you likely know even 600 RADs is debilitating and may cause death within a couple of weeks). This further complicates our endeavors as well.

I am not saying that the task is impossible, just quite difficult, and possibly beyond the tools at our disposal. We may also be straying too far off topic as well.

Addendum:

I will still try to help when and where I am able.

Well, as much as I like to hear myself talking about this things and acknowledge I probably seem to be "way off topic," I don't think it really "is" OT.

The OP asked "Why is dirty water so rare?"

One answer is that "Just because that is the way the designers made it; it actually makes no sense when assessed in terms of realworld science."

The point of all my rambling is: it seems to be rather difficult to reconcile some of the ever-present and undeniable aspects of the game with reality: Radiation does not work that way; cities should be turned to ash, not just wrecked; the idea that all the atmospheric and surface water on Earth is "radioactive," even after 200 years is seemingly impossible (even IF the sediments at the bottom of most bodies of water, DO contain relatively high proportions of radioactive isotopes).

I would like to think that the post-apocalyptic world we are presented with "makes sense" but I just think it doesn't. It just doesn't make sense at all, and thus the fact that "dirty water" is rare in game (and completely inaccessible to the player except by finding or buying cartons of it) despite the fact that there is "radioactive water everywhere" also just does NOT make sense.

I don't say this to dis the game, I love the game, and it is with some regret that I am led to this conclusion. But the game just does not make sense and so things like scarce "dirty water" shouldn't be surprising.

Well, I should add that it is pimarily the short-lived isotopes that we should be concerned with, as they tend to emit high levels of radiation over short periods of time. Long-lived isotopes, while still dangerous, emit low levels of radiation over long periods of time.

I agree completely, but I suppose thats what the suspension of disbelief is for. Even if we have to cage the scientific part of our minds to achieve that state, it can be worth in order to have fun for a time.

anyone work for NOAA ? those supercomputers they use to calculate global weather seems ideal for solving the problem of "if" and for "how long" !

Ha. One of those certainly would help, but I believe there to be to many unknowns still.

Well, I would like if we were able to derive a better answer to the question, but unfortunately I think the best we could do would be a half answer with a mssive margain for error. I know that I am not helping, but perhaps saving our time (which could be spent playing Fallout) is helping in its own way.

Some wordy responses there

When I was talking about the scarcity of Dirty Water it was just from a game mechanics point of view not one based on real world considerations.
I always thought the contamination was from particulate matter and so distillation or settlement tanks and high quality filters were the best purifying techniques.
My game logic was that Dirty Water should be a precursor to Purified Water.

I recall an XKCD What If that talks about the fuel rod pools in nuclear reactors https://what-if.xkcd.com/29/

Not to disagree with what you wrote in general but... neutron radiation (not gamma radiation) can turn matter surrounding explosion radioactive. Therefore it is not just radioactive matter of the bomb itself which is dispersed in to environment. This can be chain reaction if such activated matter begin to emit neutron radiation itself.

Such matter is dispersed in to very little, often microscopic particles which can remain in atmosphere for long time and cower very large area. Amount of direct radiation they release will depend on their concentration but indeed, in general level of radiation decreases relatively fast.

However in long term, it's not radiation itself which is dangerous. Dangerous is when radioactive particles which emits this radiation gets in to the contact with human body. Either externally (touching the skin) or internally (being breathed or digested). They cause cancer to the tissue they come in contact with. In this sense single microscopic particle can kill you many years after explosion. Of course not instantaneously.

These radioactive particles can concentrate due to food chain in living organisms. Organisms on the top of the chain (like humans) are under greater risk.

Amount of neutron radiation depends on construction of the bomb. Neutron bombs are purposely designed to release lot of neutron radiation.

Neutron radiation is absorbed rather well by the air so air explosions produce significantly less radioactive particles (and therefore fallout) then water or surface explosions.

Agree. There is however no way you can turn purified water in to dirty one by exposing it to gamma rays. At last not that I am aware of.

It IS a precursor to purified water isn't it? If you have dirty water in your inventory (or workshop) and go to a cooking bench, you can somehow "cook" it into purified water.

As someone pointed out in a previous post, this might be exactly why it is scarce and cannot be manually collected from water sources.

Heh heh . . . good to know they got those things under close supervision

Completely unrealistic. Water itself stays neutron activated for one or two days. Radioactive particles which does would not be concentrated enough to cause dangerous level of radiation. There is no possible way how you could receive hazardous amounts of radiation just by swimming in it. Not even drinking it. Drinking such water would however bring risk of getting cancer.

Another unrealistic thing was unexploded bomb in Megaton (Fallout 3) which emitted radiation. Radioactive storms are pure fiction too.