【作者】 孙桂莲；

【导师】 史建君；

【作者基本信息】 浙江大学 ， 生物物理学， 2006， 硕士

【摘要】 核电在正常运行条件下是一种安全、清洁、经济的能源。作为解决能源问题的重要途径,核电产业在我国具有十分巨大的发展空间。在核电站环境监测与评价中,¹⁴C是核电站的主要放射性气态流出物。核电站的运行可能会引起地域性的大气¹⁴C的增加,进入食物链后则会危及公众的健康和安全。因此需要对¹⁴C在环境、动植物中的行为有一较为系统的研究。本文采用模拟污染物示踪技术研究了¹⁴C在不同动植物体内的迁移与积累动态,为阐明¹⁴C的环境行为提供了基础资料。主要研究内容如下: 1.研究了水稻对¹⁴CO₃^2-的吸收和积累动态,旨在探明¹⁴C在水稻田中的行为特性。结果表明:通过水稻根系和浸于水中的茎杆下部吸收的¹⁴CO₃^2-离子会向上部组织输送并形成积累趋势;在上部组织中,叶和茎杆上部的¹⁴C比活度随时间呈逐渐上升的趋势,而穗中的比活度于14d达最大值（271.9Bq/g）后又呈下降趋势;茎杆下部由于直接浸于水中,表现出对¹⁴CO₃^2-离子的快速吸收、吸附,此后随时间呈下降趋势,根部由于深入水稻土中,表现出上升过程迟后于茎杆下部,其¹⁴C比活度也低于茎杆下部:上部组织（穗、叶和茎杆上部）中¹⁴C的百分含量随时间上升,而下部组织（茎杆下部和根）则相反,至试验后期（21d-35d）,其百分含量基本持平（约各占50%）,¹⁴C从下部组织向上部组织输送的特征非常明显。 2.研究了¹⁴CO₃^2-在红鲤体内的分布与积累动态。结果表明:在红鲤各部位中均检测到了¹⁴C的存在,表明红鲤会从水体中摄入、吸附¹⁴CO₃^2-,并在各组织器官中积累。红鲤从水体中摄入和吸收¹⁴CO₃^2-的主要器官是肠胃道（内脏）,与水体直接接触而吸附、吸收的¹⁴CO₃^2-主要集中在鱼鳃、鱼鳍和鱼鳞中,肉、皮和骨中的¹⁴C比活度相对较低,但远远高于本底,表明由内脏、鱼鳃等组织吸附、吸收的¹⁴CO₃^2-除大部分被排泄、解吸外,仍有部分输运到了鱼体的内部组织。鱼体各部位中¹⁴C的比活度差异很大,其大小次序为:内脏>鱼鳃、鱼鳍>鱼鳞>鱼头、鱼骨>鱼皮、鱼肉。 3.研究了¹⁴CO₃^2-在水—金鱼藻系统中的消长动态,并运用计算机拟合、建立其动力学模型。结果表明:引入水体的¹⁴CO₃^2-离子由于金鱼藻的吸附、吸收及转化分解为¹⁴CO₂气体散逸而使水体中的¹⁴C比活度快速下降。金鱼藻因其羽状复叶具有较大的比更多还原

【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>32 ions 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.更多还原