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Тақырып өзектілігі. Қазба байлықтарды өндіру кезіндегі қалыптасатын қоршаған ортаның өзгерістері және индустрияның, агроөнеркәсіптік жүйелердің дамуына бағытталған ірі көлемді энергетикалық жобаларды қолдану адам мен табиғи бірлестік үшін жаңа экологиялық жағдайларды тудырады [Шевченко В.А., 1989]. Атап айтқанда, Қазақстанда бұрынғы кеңес одағындағы уранның 40 %-ға жуығының өндірілуіне байланысты, уран өндірісінің радиоактивті қалдықтарымен ластанған жалпы ауданы 10 000 га, радиоактивті белсенділігі 250 000 Кu болатын аймақтардың пайда болуына әкеп соқтырды.
Цитогенетические эффекты радиации изучены на двух видах мышевидных грызунов (Allactaga major Kern., Allactaga saltator Eversman), которые обитают в уранодобывающих регионах Акмолинской области. Животные были отловлены за санитарно-защитной зоной хвостохранилища в северо-восточном направлений Степногорского горно-химического комбината (в 100-200 м от санитарно-защитной зоны хвостохранилища). В качестве контроля были исследованы аналогичные виды мышевидных грызунов, обитающие в относительно радиоактивно незагрязненном участке. В работе использовали радиометрические, радиоспектрометрические и радиохимические, цитогенетические и статистические методы исследования.
Положения, выносимые на защиту
1 У мышевидных грызунов, обитающих в условиях хронического низкоинтенсивного облучения, цитогенетическая нестабильность достоверно выше контрольного уровня.
2 Частота встречаемости клеток с гиподиплоидами, гипердиплоидами и хромосомными аберрациями и количество эритроцитов крови с микроядрами у мышевидных грызунов в уранодобывающих регионах могут использоваться в целях биоиндикации техногенного загрязнения среды.
3. Полученные цитогенетические данные дают возможность оценить воздействие ионизирующих излучений на популяции животных и прогнозировать отдаленные генетические последствия.
Выводы
1 В местах обитания мышевидных грызунов на территориях влияния хвостохранилища Степногорского горно-химического комбината мощность эквивалентной дозы гамма-излучения и плотность потока бета-частиц превышает показатели контрольных участков в 6 и 15 раз соответственно.
2 Активность радионуклидов 238U, 226Ra, 232Th и 210Pb в почве, воде и растениях в опытных участках превышает контроль в 2- 52 раза. Величина поглощенной дозы ионизирующего излучения у мышевидных грызунов, обитающих на радиоактивно-загрязненных участках в 10 - 19 раз превышает показатели у контрольных животных.
3 Выявленные нарушения цитогенетической нестабильности у природной популяций мышевидных грызунов, обитающих вокруг хвостохранилища Степногорского горно-химического комбината могут служить биоиндикаторами техногенного загрязнения территорий. Показано, что частота встречаемости клеток с гиподиплоидным и гипердиплоидным набором клеток костного мозга у больших тушканчиков (Allactaga major Kern.) превышает контрольные показатели в 1,8 и 3,5 раза, а у тушканчиков прыгунов (Allactaga saltator Eversman.) в 1,7 и 4,1 раза.
4 Частота полиплоидных клеток у больших тушканчиков (Allactaga major Kern.), отловленных на радиактивно-загрязненном участках в 2,7 раза больше чем у контрольных животных, а у тушканчиков- прыгунов (Allactaga saltator Eversman.) этот показатель превышает контроль в 6,4 раза.
5 Частота хромосомных перестроек клеток костного мозга у популяции мышевидных грызунов видов тушканчиков прыгунов (Allactaga saltator Eversman.) и большого тушканчика (Allactaga major Kern.) в среднем в 4-6 раз превышает показатели у контрольных животных, что указывает на хронический характер воздействия ионизирующего излучения.
6 Частота встречаемости эритроцитов крови с микроядрами у Allactaga major Kern. и Allactaga saltator Eversman., обитающих на радиоактивно-загрязненных участках в 2 и 2,6 раза выше чем у контрольных животных.
SUMMARY
Altaeva Nursulu Zakiriyaevna
Dissertation for the degree of candidate of biological sciences
«Cytogenetic study of murine rodents inhabiting
in uranium-mining regions of Akmolinskaya oblast»
03.00.01- radiobiology
Project topicality. Republic of Kazakhstan is ranked as the world’s leading uranium ore reserves. About 25% of the world’s proven uranium ore reserves occur here. Large-scale mining activity of the 20 uranium deposits in Kazakhstan lasted more than 40 years. At that time uranium output approached to about 40% of the total quantity of uranium mined in former USSR. More than 200 million tons of radioactive wastes amassed as mill tailings, dense leaching piles of hydrometallurgical plants’ tailings and unprocessed and processed uranium ore which harmfully impact on the environment and the population health. Strategy of study concerning ecology effects conditioned by ionizing radiation includes as one main element an analysis of genetic processes in natural populations and ecosystems. Therefore analysis of cytogenetic effects of murine rodents inhabiting in influence zones of uranium-mining regions is one of the most important elements of radio-bio-ecological monitoring and are not completed so far.
Research goal is studying of radiation situation in the natural habitat of murine rodents in uranium-mining regions of Akmolinskaya oblast and assessment of cytogenetic effects induced by anthropogenic pollution impact on rodent population.
Research tasks:
Scientific novelty
Radioecological situation in habitats of murine rodents was explored. It was shown that gamma radiation equivalent dose rate 6 times and beta-particle flux density 15 times exceed check measurements. In soil, plant, and water samples the concentrations of 238U, 226Ra, 232Th, and 210Pb exceed the testing level 2 to 52 times.
Absorbed dose by murine rodents inhabited in radioactive contaminated areas exceeds 10 to 19 times control animals.
For the first time murine rodents (Allactaga major Kern., Allactaga saltator Eversman.), inhabited in uranium-mining regions of Akmolinskaya oblast has studied by cytogenetic method. As a result of study of mutational processes in murine rodents it was ascertained that cytogenetic instabilities in bone marrow connected with increase of frequency of occurrence of cells with hyperdiploidy, polyploidy, and chromosomal aberrations. For the first time it is ascertained that the level of blood erythrocytes with micro-nucleus in murine rodents inhabited on radioactive contaminated territories reliably higher than analogues factor for conditional control populations.
Materials and methods
Research of radio-ecological state in the areas of habitat of murine rodents supposes implementation of radiometric survey and sampling of soil, plants, and water. Radiometric survey of dwelling places of murine rodents includes gauging of gamma radiation equivalent dose rate and determination of alpha- and beta-particles surface density of contamination carried out by dosimeter «RКS-01-SОLО» with appropriate blocks of detection.
Cytogenetic effects of radiation were studied by two species of murine rodents (Allactaga major Kern, Allactaga saltator Eversman.) inhabited in uranium-mining regions of Akmolinskaya oblast. Experimental animals were captured on the territory located to the North-East to tailing of Stepnogorsk Mining-Chemical Complex. As a control analogues species of murine rodents inhabited on the territories located 10-20 km apart from Stepnogorsk. Radiometric, radio-spectrometric, radiochemical, cytogenetic, and statistic methods were used in the research work.
Following statements are chosen for defence
1 Cytogenetic instability is reliably higher than the control level for murine rodents inhabited in conditions of chronically low level of radiation.
2 Rate of occurrence of cells with hypodiploidy, hyperdiploidy, polyploidy, and chromosomal aberrations and level of blood erythrocytes with micronucleus in murine rodents inhabiting in uranium-mining regions may be used in bio-indication purposes.
3 Anthropologic contamination of separate areas of habitat for natural populations of animals requires decontamination and territory rehabilitation action plan.
Conclusions
1 In habitat of murine rodents in influence zone of Stepnogorsk Mining-Chemical Complex tailing it is shown that gamma radiation equivalent dose rate and beta-particle flux density exceed from 6 to 15 times check measurements.
2 In soil, plant, and water samples the activity of radionuclides like 238U, 226Ra, 232Th, and 210Pb exceeds the testing level from 2 to 52 times. Dose of ionizing radiation absorbed by murine rodents inhabited in radioactive contaminated areas exceeds from 10 to 19 times the one absorbed by control animals.
3 Big Jerboa (Allactaga major Kern.) inhabited nearby of Stepnogorsk Mining-Chemical Complex tailing has rate of occurrence of cells with hypodiploidy, and hyperdiploidy in hematopoietic tissue which correspondingly 1,85, and 3,5 times exceeds the control level; and this factor of Jerboa (Allactaga saltator Eversman.) is correspondingly 1,7, and и 4,1 times higher than control level.
4 Rate of occurrence of cells with polyploidy in Big Jerboa (Allactaga major Kern.) from radioactively contaminated areas is 2,7 times higher than in control animal; and this factor of Jerboa (Allactaga saltator Eversman.) by 6,4 times exceeds control level.
5 Levels of chromosomal rearrangements of Big Jerboa (Allactaga major Kern.) from trail and control areas are 3,39±0,60% and 0,60±0,19% correspondently; and these factors of Jerboa (Allactaga saltator Eversman.) are 4,63±0,91% and 1,22±0,37%, correspondently which confirms existence of chronic exposure of ionizing radiation.
6 Rate of occurrence of blood erythrocytes with micro-nucleus in murine rodents (Allactaga major Kern. and Allactaga saltator Eversman.) inhabited on radioactive contaminated territories reliably from 2 to 2,6 times higher than analogues factor for conditional control populations.
Басуға 27.05.2010 жылы қол қойылды
Пішіні: 60х84/16 №1 баспаханалық қағаз.
Шартты баспа табағы: 1,0
Таралымы: 100 дана Тапсырыс: 192
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