环境生态修复

1、切尔诺贝利 (Chernobyl),09721546,BEA Confidential. | 2,Context Lists,BEA Confidential. | 3,切尔诺贝利核电站位于乌克兰的普里皮亚（Pripyat），切尔诺贝利市西北18千米，离乌克兰与白俄罗斯边界16千米，及乌克兰首都基辅110千米。 核电站由四个反应堆组成，每个能产生1千兆瓦特的电能，核事故发生时四个反应堆共提供了乌克兰10%的电力。 厂房的工程始于20世纪70年代，1号反应堆于1977年启用，接着2号(1978年)、3号(1981年)、4号(1983年)亦相继启用。还有两个反应堆(5号及6号，每个能产生10亿瓦特

2、)在事故时仍在建造中。,背景,BEA Confidential. | 4,BEA Confidential. | 5,1986年4月26日核电站的第4号核反应堆在进行半烘烤实验中突然失火，引起爆炸，其辐射量相当于500颗美国投在日本的原子弹。爆炸使机组被完全损坏，8吨多强辐射物质泄露，尘埃随风飘散，致使俄罗斯、白俄罗斯和乌克兰许多地区遭到核辐射的污染。 2005年一份国际原子能机构的报告认为直到当时有56人丧生47名核电站工人及9名儿童患上甲状腺癌并估计大约4000人最终将会因这次意外所带来的疾病而死亡。绿色和平组织及其他人都对研究结果作出争论。 2006年4 月25 日电在乌克兰切尔诺贝利核

3、电站事故20 周年之际，中国驻乌克兰特命权大使高玉生与乌克兰经济部长雅采纽克25 日在乌政府大厦分别代表两国政府签署协定，中国政府将向乌方提供价值1000 万元人民币(约合125 万美元)的专项无偿援助，用于消除切尔诺贝利核电站事故后果。,BEA Confidential. | 6,污染区域,中央污染区 该区位于明斯克城以西和西北部, 污染面积不大(直径为15 20 km) ,区内的污染点是在事故发生的最初几天里,由于称之“北向的”核粒子幅射径迹活动形成的,污染点连接一起呈近似纬线方向伸展的污染区. 137 Cs 的污染度为3.710411.1104 Bq/ m2 ,部分为18.5 104 B

4、q/ m2 ,个别达到55.5104 Bq/ m2 .,西南污染区 该区位于普里皮亚特森林低地南部, 是耶尔斯克到平斯克的众多污染点构成的污染区. 这里分布着大面积的沼泽, 地表的冲积和湖积砂层发育, 约有50 %的土地经排水改造. 137Cs 的污染度为3.710418.5104 Bq/ m2 , 部分地方达37.010418.5104 Bq/ m2 , 从原子能发电站的方向呈现递减.,东部污染区 主要包括奥尔沙- 莫吉廖夫黄土高原和第聂伯河左岸地区的契尔冰碛平原, 右侧伸展至别列津纳中央冰水平原的狭长地带. 137Cs 的污染度达55.5 10414.1104 Bq/ m2 或更高.,东南

5、污染区 位于戈麦尔森林低地边缘, 处于整个污染期的污染源影响下. 该区的地表由冰水、湖冲积和沼泽沉积物构成. 除 137 Cs(55.5 104148.0 104 Bq/ m2) 外, 污染物中还有90Sr (18.5 104 Bq/ m2) , 该区南部还有Pu 同位素.,BEA Confidential. | 7,BEA Confidential. | 8,BEA Confidential. | 9,生态修复措施研究,Six types of remedial actions are considered in the program system ReSCA（Remediation St

6、rategies after the Chernobyl Accident ）. (Ulanovsky et al., submitted for publication) Radical improvement of grassland (RI) Application of ferrocyn (a mixture of 5% KFeFe(CN)6 and 95% Fe4Fe(CN)6) to cows (FA) Feeding pigs with uncontaminated fodder before slaughter (FP) Application of mineral ferti

7、lizers for potato fields (MF) Information campaign on mushrooms and other forest produce (IM) Replacement of contaminated soil in populated areas by uncontaminated soil (RS).,BEA Confidential. | 10,BEA Confidential. | 11,Phytoremediation of Radiocesium-Contaminated Soil in the Vicinity of Chernobyl,

8、 Ukraine,Identify extractants that may be used to solubilize 137Cs in soil solution Study the effect of soil amendments on 137Cs accumulation by plants Evaluate the applicability of phytoextraction for environmental restoration of soil contaminated with 137Cs.,BEA Confidential. | 12,Extraction of 13

9、7Cs from Soil.,The availability of 137Cs to the plants in Chernobyl soil was limited, because this radionuclide was tightly bound to exchange sites of soil particles or incorporated into the crystalline structure of primary and secondary minerals. Out of 20 soil amendments tested to increase 137Cs d

10、esorption/solubility in the soil. Ammonium salts were found to be the most practical soil amendment that can potentially increase 137Cs bioavailability.,BEA Confidential. | 13,BEA Confidential. | 14,FIGURE 1. Sequential desorption of 137Cs from the Chernobyl soil with ammonium acetate (0.1 M). A soi

11、l sample of 133 g was placed in a plastic bottle and then mixed with 1 L of a treatment solution.The bottles with the soil/extractant suspension were sealed and placed on an end-over-end shaker at room temperature for 1, 3, 7,and 14 days, respectively. After the equilibration, the slurry wasfiltered

12、 through cheesecloth filter, and the filtrate was centrifugedat 2000 rpm for 12 min. The resulting supernatant was used for 137Csactivity determination. Remaining soil was used for sequential extraction.,BEA Confidential. | 15,Screening of Plants for the 137Cs Accumulation,Sixteen high biomass culti

13、vars of 10 species were screened for 137Cs accumulation A large group of plants, including the majority of the Amaranth cultivars, peas, and sunflower, had an overall yield close to 500 g of dried biomass per m2 Amaranthus retroflexus cvs. aureus and PT-95 were the leading cultivars in total radioac

14、tivity removal from the soil,BEA Confidential. | 16,BEA Confidential. | 17,137Cs Compartmentalization in Plants.,Radiocesium compartmentalization within the plant was studied in corn,sunflower, and Indian mustard.,Roots of these species had 2.5-3.4 times greater 137Cs activity compared to the aboveg

15、round parts,A positive correlation was found between 137Cs activity in the roots and 137Cs activity in the shoots.,BEA Confidential. | 18,Impact of Soil Amendments on 137Cs Accumulation by Plants.,BEA Confidential. | 19,BEA Confidential. | 20,The harvested mature seeds of first generation soybean(G.

16、 max, L. variety Solnyechnaya). (A) Mature seeds from control and contaminated Chernobyl fields. (B) Imbibition dynamics of control and the seeds from contaminated fields within 360 min.(C) Morphological characterization of control seeds and the seeds from contaminated fields: length, width, and wei

17、ght.,BEA Confidential. | 21,小结,植物修复是可行的一个方案，但是还需要继续筛选高富集作物。 适当添加肥料促进对137CS的吸收。 培育一些抗辐射的作物，提高作物的生长能力。,BEA Confidential. | 22,参考文献,卡达茨基，班巴洛夫，张则有，王铁林.契尔诺贝利核污染与治理J.东北师大学报自然科学版，1997，No,4. P. Jacob , S. Fesenko etc. Rural areas affected by the Chernobyl accident: Radiation exposure and remediation strategiesJ. Science of the Total Environment 408 (2009) 1425 SLAVIKDUSHENKOV etc. Phytoremediation of Radiocesium-Contaminated Soil in the Vicinity