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Absorption and Accumulation Dynamics of ～(14)C Released from Nuclear Power Station in Animals and Plants

Author: SunGuiLian
Tutor: ShiJianJun
School: Zhejiang University
Course: Biophysics
Keywords: 14C rice red common carp hornwort quail distribution accumulation accumulation and disappearance dynamic concentration factor ecosystem radio ecology radionuclide
CLC: X171
Type: Master's thesis
Year: 2006
Downloads: 121
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Abstract

Nuclear power is a kind of safe, clean and economical energy sources which runs in natural condition. As an important approach to resolving energy sources problems, nuclear power industry has immense development space in our country. ¹⁴C is one main radioactive gaseous efflux that can make an important effect on the environment of nuclear power station neighborhood. It could be increasing regionally aroused by nuclear power station’s running, and do harm to people’s health after it transfers into food chains. So it needs to have a systemic study on behaviors of ¹⁴C in environment and propagations. The transfer and accumulation dynamic of ¹⁴C in different ecosystems and propagations were studied by using isotope-tracer technology and that offered some basic information for illuminating the behaviors of ¹⁴C in environment. The primary contents of study are as follows:1. Dynamic of absorption and accumulation of ¹⁴ CO₃^2- in rice was studied by using isotope-tracer technology, which was in order to proving up the behavior of ¹⁴CO₃^2- in rice paddy. The results showed that: ⁽14 CO₃^2- ions absorbed by roots and lower part of stems （LPS） in water were transferred to upper part of rice （UPR）, and presented an accumulation tendency. In UPR, the specific activity of ¹⁴C in leaves and upper part of stems （UPS） tended to increase with time. But that in tassels tended to decrease after reaching the maximum （271.9Bq/g） at the 14th day. ¹⁴ CO₃^2- ions were absorbed quickly in LPS dipping in water, and then slowly declined. Compared with LPS, the increasing tendency in roots was later and the specific activity of ¹⁴C was also lower as roots embed in soil. The content percent of ¹⁴C in UPR （tassels, leaves and UPS） was increscent with time, but reversed in LPR. During the late stage of experiment （21d-35d）, content percents in both UPR and LPR were equal on the whole （about 50% respectively）. The characteristic of ¹⁴C transferred from LPR to UPR was greatly evident.2. The distribution and accumulation dynamics of ¹⁴ CO₃^2- in red common carp was studied by using isotope-tracer technology. The results showed that: ¹⁴C was detected in all parts of red common carp. It suggested that the ¹⁴ CO₃^2- ions in water were ingested andadsorbed by red common carp, and accumulated in different apparatus. The main apparatus of red common carp to ingest and absorb 14CC>32" ions was intestines and stomach （viscera）. 14CO32" of adsorption or absorption by direct contact with water mainly concentrated on the gill, fin and scale. The specific activity of I4C in meat, skin and bone was lower, but much higher than the level of background. All that showed although most of 14CC>32ions adsorbed and absorbed by viscera, gill and et al were egested and desorbed, some of them were still transported to inner organs. The specific activity diversity of 14C in different parts of red common carp was greatly obvious. The order in different parts is: viscera>gill, fin>scale>head, bone>skin, meat.3. The accumulation and disappearance dynamic of 14CC>32" in water-horn wort system was studied adopting isotope-tracer technology and its kinetic models were set up applying computer. The specific activity of 14C in waters reduced quickly because 14C ion drowed into waters decomposed to 14 CO2 gas dissipate due to adsorption, adsorption and transformation of hornwort. Homwort had stronger adsorb and absorb actions on 14C in waters, because its pinnately compound leaves possessed bigger specific surface area;and its accumulation of 14C was mainly in new leaf organization. The specific activity of 14C in new leaf appeared greatest value of 29656.59 Bq/g at 21d, with distribution percent reching 86.34%;both the disappearance dynamic of 14C in water and accumulation dynamic in hornwort both followed the first order reaction kinetics model （Y^Ae^’ffl Y=Aehl）;Each parts of hornwort all possessed very strong accumuliation action on 14C in waters, and could be used for monitoring and purifying the 14C polluted water. The concentration factor CF and time t was linear regression relation, i.e. CF= A+ Bt.4. The accumulation and distribution dynamic of airborne I4C in different parts of quail was studied by using isotope-tracer technology. The results showed that: a little airborne 14C into quail via breathing, sedimentation and ingestion transferred to all pats of organism. The accumulation effect of 14C in endothelium of stomach and liver was evidence. Their specific activity of I4C increased linearly along with immitting of airborne I4C by equally dose and time distance, which accorded with linear equations y = 4.6321 x + 3.7747 （R2 = 0.9838） and y = 3.6703x + 6.3317 （R2 = 0.9957） respectively. Radioactivity percent of I4C in meat andborn is high and 30⁴5% and 20³0% respectively.

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