Fallout countermeasures Nuclear fission product

1 fallout countermeasures

1.1 iodine
1.2 caesium
1.3 strontium

fallout countermeasures

the purpose of radiological emergency preparedness protect people effects of radiation exposure after nuclear accident or bomb. evacuation effective protective measure. however, if evacuation impossible or uncertain, local fallout shelters , other measures provide best protection.

iodine

per capita thyroid doses in continental united states of iodine-131 resulting exposure routes atmospheric nuclear tests conducted @ nevada test site. see downwinders.

at least 3 isotopes of iodine important. i, (radioiodine) , i. open air nuclear testing , chernobyl disaster both released iodine-131.

the short-lived isotopes of iodine particularly harmful because thyroid collects , concentrates iodide – radioactive stable. absorption of radioiodine can lead acute, chronic, , delayed effects. acute effects high doses include thyroiditis, while chronic , delayed effects include hypothyroidism, thyroid nodules, , thyroid cancer. has been shown active iodine released chernobyl , mayak has resulted in increase in incidence of thyroid cancer in former soviet union.

one measure protects against risk radio-iodine taking dose of potassium iodide (ki) before exposure radioiodine. non-radioactive iodide saturates thyroid, causing less of radioiodine stored in body. administering potassium iodide reduces effects of radio-iodine 99% , prudent, inexpensive supplement fallout shelters. low-cost alternative commercially available iodine pills saturated solution of potassium iodide. long-term storage of ki in form of reagent grade crystals.

the administration of known goitrogen substances can used prophylaxis in reducing bio-uptake of iodine, (whether nutritional non-radioactive iodine-127 or radioactive iodine, radioiodine - commonly iodine-131, body cannot discern between different iodine isotopes). perchlorate ions, common water contaminant in usa due aerospace industry, has been shown reduce iodine uptake , classified goitrogen. perchlorate ions competitive inhibitor of process iodide actively deposited thyroid follicular cells. studies involving healthy adult volunteers determined @ levels above 0.007 milligrams per kilogram per day (mg/(kg·d)), perchlorate begins temporarily inhibit thyroid gland’s ability absorb iodine bloodstream ( iodide uptake inhibition , perchlorate known goitrogen). reduction of iodide pool perchlorate has dual effects – reduction of excess hormone synthesis , hyperthyroidism, on 1 hand, , reduction of thyroid inhibitor synthesis , hypothyroidism on other. perchlorate remains useful single dose application in tests measuring discharge of radioiodide accumulated in thyroid result of many different disruptions in further metabolism of iodide in thyroid gland.

treatment of thyrotoxicosis (including graves disease) 600-2,000 mg potassium perchlorate (430-1,400 mg perchlorate) daily periods of several months or longer once common practice, particularly in europe, , perchlorate use @ lower doses treat thryoid problems continues day. although 400 mg of potassium perchlorate divided 4 or 5 daily doses used , found effective, higher doses introduced when 400 mg/day discovered not control thyrotoxicosis in subjects.

current regimens treatment of thyrotoxicosis (including graves disease), when patient exposed additional sources of iodine, commonly include 500 mg potassium perchlorate twice per day 18–40 days.

prophylaxis perchlorate-containing water @ concentrations of 17 ppm, corresponds 0.5 mg/kg-day personal intake, if 1 70 kg , consumes 2 litres of water per day, found reduce baseline radioiodine uptake 67% equivalent ingesting total of 35 mg of perchlorate ions per day. in related study subjects drank 1 litre of perchlorate-containing water per day @ concentration of 10 ppm, i.e. daily 10 mg of perchlorate ions ingested, average 38% reduction in uptake of iodine observed.

however, when average perchlorate absorption in perchlorate plant workers subjected highest exposure has been estimated approximately 0.5 mg/kg-day, in above paragraph, 67% reduction of iodine uptake expected. studies of chronically exposed workers though have far failed detect abnormalities of thyroid function, including uptake of iodine. may attributable sufficient daily exposure or intake of healthy iodine-127 among workers , short 8 hr biological half life of perchlorate in body.

to block uptake of iodine-131 purposeful addition of perchlorate ions populace s water supply, aiming @ dosages of 0.5 mg/kg-day, or water concentration of 17 ppm, therefore grossly inadequate @ reducing radioiodine uptake. perchlorate ion concentrations in region s water supply need higher, @ least 7.15 mg/kg of body weight per day, or water concentration of 250 ppm, assuming people drink 2 liters of water per day, beneficial population @ preventing bioaccumulation when exposed radioiodine environment, independent of availability of iodate or iodide drugs.

the continual distribution of perchlorate tablets or addition of perchlorate water supply need continue no less 80–90 days, beginning after initial release of radioiodine detected. after 80–90 days passed, released radioactive iodine-131 have decayed less 0.1% of initial quantity, @ time danger biouptake of iodine-131 over.

in event of radioiodine release, ingestion of prophylaxis potassium iodide, if available, or iodate, rightly take precedence on perchlorate administration, , first line of defense in protecting population radioiodine release. however, in event of radioiodine release massive , widespread controlled limited stock of iodide , iodate prophylaxis drugs, addition of perchlorate ions water supply, or distribution of perchlorate tablets serve cheap, efficacious, second line of defense against carcinogenic radioiodine bioaccumulation.

the ingestion of goitrogen drugs is, potassium iodide not without dangers, such hypothyroidism. in these cases however, despite risks, prophylaxis benefits of intervention iodide, iodate, or perchlorate outweigh serious cancer risk radioiodine bioaccumulation in regions radioiodine has sufficiently contaminated environment.

caesium

the chernobyl accident released large amount of caesium isotopes dispersed on wide area. cs isotope of long-term concern remains in top layers of soil. plants shallow root systems tend absorb many years. hence grass , mushrooms can carry considerable amount of cs, can transferred humans through food chain.

one of best countermeasures in dairy farming against cs mix soil ploughing soil. has effect of putting cs out of reach of shallow roots of grass, hence level of radioactivity in grass lowered. removal of top few centimeters of soil , burial in shallow trench reduce dose humans , animals gamma photons cs attenuated passage through soil. deeper , more remote trench is, better degree of protection. fertilizers containing potassium can used dilute caesium , limit uptake plants.

in livestock farming, countermeasure against cs feed animals prussian blue. compound acts ion-exchanger. cyanide tightly bonded iron safe human consume several grams of prussian blue per day. prussian blue reduces biological half-life (different nuclear half-life) of caesium. physical or nuclear half-life of cs 30 years. caesium in humans has biological half-life of between 1 , 4 months. added advantage of prussian blue caesium stripped animal in droppings in form not available plants. hence prevents caesium being recycled. form of prussian blue required treatment of animals, including humans special grade. attempts use pigment grade used in paints have not been successful.

strontium

the addition of lime soils poor in calcium can reduce uptake of strontium plants. likewise in areas soil low in potassium, addition of potassium fertilizer can discourage uptake of caesium plants. such treatments either lime or potash should not undertaken lightly can alter soil chemistry greatly, resulting in change in plant ecology of land.