tag:blogger.com,1999:blog-1236895917331192509.post8648570127867474057..comments2023-05-17T04:01:26.506-04:00Comments on The Neutron Economy: Situation stabilizing at FukushimaAnonymoushttp://www.blogger.com/profile/12086026121605548134noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-1236895917331192509.post-89339746185651950702011-04-05T16:15:06.668-04:002011-04-05T16:15:06.668-04:00As far as I understand, cesium does not tend to bi...As far as I understand, cesium does not tend to bio-accumulate - i.e., it tends to be excreted from the body, unlike heavy metals (mercury, lead, etc.) or iodine & strontium.<br /><br />Sr-90 may be a concern, given that it is bone-seeking (it acts like calcium) and has a half-life of 30 years - however, so far reports have not indicated high levels of strontium found.<br /><br />Iodine levels are a concern, however iodine is short-lived - meaning a combination of time and dilution will likely run its course there. However, the bio-accumulation process is how it ends up in meat and milk - iodine as a gas tends to precipitate with water and end up on plants and soil, where it ends up in plants, meat, and milk. <br /><br />As far as cesium goes, the big concern is making sure no more gets out of the plant itself - otherwise, dilution will likely take care of the issue as far as that goes.Anonymoushttps://www.blogger.com/profile/12086026121605548134noreply@blogger.comtag:blogger.com,1999:blog-1236895917331192509.post-30687408870861938172011-04-05T16:04:11.226-04:002011-04-05T16:04:11.226-04:00The news from today is that iodine-131, 1M times h...The news from today is that iodine-131, 1M times higher than the "safe" limit is measured in the ocean near the Fukushima Plant. I understand that iodine-131 is a short lived isotope unlike iodine 131, strontium, cesium...<br /><br />My question is what would the effects of bio-accumulation be on predator fish (Salmon, Tuna, etc...) from fall spillage from Fukushima? Bio-accumulation is essentially the stacking of pollutants as the pollutants move up a food chain. Similiar to the problem of Mercury in Tuna. <br /><br />Any ideas -clautz06http://civilusdatum.comnoreply@blogger.comtag:blogger.com,1999:blog-1236895917331192509.post-89413496858301739652011-03-21T14:04:47.210-04:002011-03-21T14:04:47.210-04:00When you say exclusion zone are you talking about ...When you say exclusion zone are you talking about the evacuated area? The definition I had in mind was the area around the plant where no development is allowed to occur only as a buffer. I've found the areas of the Fukushima plants to be about 850 and 300 acres, which is Tepco owned land, and I suspect development begins at this boundary, even though it is much smaller than US plants (although I only have a limited sample size), that's Japan for you (plus being on the coastline technically only requires half the area).<br /><br />I find it probable that there is productive land outside the plant boundary that will be not usable for its previous purpose after the dust settles, but this is completely speculative. Otherwise, I don't see why the majority of the evacuated zone won't have the prior use available to it.Alanhttps://www.blogger.com/profile/16161965850899477592noreply@blogger.comtag:blogger.com,1999:blog-1236895917331192509.post-52417227852710222322011-03-21T09:39:13.061-04:002011-03-21T09:39:13.061-04:00Alan: All of those are beta emitters, so the Quali...Alan: All of those are beta emitters, so the Quality Factor (QF) is 1. (Ba-137, the daughter of Cs-137, undergoes a gamma decay shortly after.) So, take any dose you see in grays and it's pretty much the same in sieverts.<br /><br />I looked around for the maximum concentration in food, by the way - for I-129, it's 300 Bq/kg (for lay folks: that's 300 decays per second, per kilogram of material). <br /><br />WHO publishes a document on <a href="http://www.codexalimentarius.net/web/more_info.jsp?id_sta=17" rel="nofollow">recommended maximum levels of radioisotopes</a> in foods. For Cs-137, the relevant level is around 1000 Bq/kg; for Sr-90, I-129 and I-131, the number seems to be 100 Bq/kg. Radionuclides are on page 33. <a href="http://www.cnn.com/2011/WORLD/asiapcf/03/21/japan.nuclear.food/index.html?hpt=T2" rel="nofollow">CNN indicates</a> that the Japanese limit for drinking water for I-131 appears to be 300 Bq/kg (which is currently being exceeded).<br /><br />What I meant by immediate-term risk was for folks outside of the exclusion zone - that is, the levels outside of there pose little real health risk. Obviously, you're correct - inside the exclusion zone is a different story.Anonymoushttps://www.blogger.com/profile/12086026121605548134noreply@blogger.comtag:blogger.com,1999:blog-1236895917331192509.post-90513470317005397082011-03-21T06:24:46.868-04:002011-03-21T06:24:46.868-04:00What are the emitted particles from the Sr, I, Cs,...What are the emitted particles from the Sr, I, Cs, etc and what are the corresponding weighting factors? If one knows that and the relative contribution to the unweighted dose of each species, then they could get a very rough multiplier for the numbers being constantly reported in Grays.<br /><br />Maybe when you said immediate-term risk you meant intermediate-term risk. I would expect the intermediate-term risk to still be possible as one gets closer to the plant site and the exclusion zone (I think this is a part of the reason we have it). Where to draw the line could be a high-value question.Alanhttps://www.blogger.com/profile/16161965850899477592noreply@blogger.com