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CHEMICAL CYCLES AND HEALTH RISKS OF SOME CRUSTAL NUCLIDES.

機譯：一些地殼核的化學循環(huán)和健康風險。

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Within the field of geochemistry there have been rapid advances in the ability to observe and describe natural systems interactions at all scales. Analysis of energy systems impacts on the environment requires quantification of short and long term local, regional and global modifications. This dissertation describes and utilizes an approach for assessing long term health risks due to dispersion of naturally occurring radionuclide series and chemical toxins by normal and altered landscape chemical cycles. In particular, the health risks resulting from geochemical mobilizations of arsenic, lead, uranium and radium are considered. Based on a review of toxic waste hazard measures and risk assessment studies, a general expression is developed for quantifying health risks imposed by the introduction of toxic materials to components of the total environment. This general measure deals with long term interactions within and between the internal human environment and the external biogeochemical environment.; Health hazards are expressed as dose factors which convert environmental concentrations into a corresponding dose field (organ doses in rad for radionuclides; daily intake for toxic elements). The dose field is translated into population health risk expressed as lifetime cancer risk for carcinogens and average blood levels for other toxins.; The external environment is modelled by considering the nature of the earth system and the manner in which elements are distributed and mobilized within the system. The landscape cell (or prism) is presented as a tool for visualizing and mapping toxic material cycles near the crustal surface. The overall process is incorporated in the GEOTOX code which is a geochemical systems model for describing the dynamics of crustal toxins within a landscape and the resulting health risks. GEOTOX is used to investigate the response of regional landscapes to increased soil and rock inventories of ('238)U, ('226)Ra, arsenic and lead. It is found that each decay series of element imposes a hazard by its behavior in the total environment that can not be quantified by a simle measure of toxicity. GEOTOX is used to follow continuous releases of the four toxins to steady state. The results provide the source fluxes in g/km('2)/y(and Ci/km('2)/y) to soil or groundwater that result in an incremental increase of population cancer risk of 10('-5) per individual. For lead the corresponding blood level increase is set at 5 g/100ml. GEOTOX is also used to model the risk field induced by the migration of the uranium series from a uranium ore body through a hypothetical landscape. A review of the genesis of anomalous uranium zones in sedimentary rock is presented and forms the basis for proposing the reference ore body.
機譯：在地球化學領(lǐng)域，觀察和描述各種規(guī)模的自然系統(tǒng)相互作用的能力得到了迅速的發(fā)展。能源系統(tǒng)對環(huán)境的影響分析需要對短期和長期的局部，區(qū)域和全球變化進行量化。本論文描述并利用了一種方法，用于評估由于自然發(fā)生的放射性核素系列和化學毒素通過正常和變化的景觀化學循環(huán)而散布造成的長期健康風險。尤其要考慮到由于砷，鉛，鈾和鐳的地球化學動員所造成的健康風險。在對有毒廢物危害措施進行審查和進行風險評估研究的基礎(chǔ)上，開發(fā)了一種通用表達式，用于量化將有毒物質(zhì)引入整個環(huán)境組成部分所帶來的健康風險。該一般措施涉及內(nèi)部人類環(huán)境與外部生物地球化學環(huán)境之間以及它們之間的長期相互作用。健康危害表示為將環(huán)境濃度轉(zhuǎn)換為相應(yīng)劑量場的劑量因子（放射性核素的器官劑量以弧度表示；有毒元素的每日攝入量）。劑量字段被轉(zhuǎn)換為人口健康風險，表示為終身致癌物癌癥風險和其他毒素的平均血液水平。通過考慮地球系統(tǒng)的性質(zhì)以及元素在系統(tǒng)中的分布和動員方式來對外部環(huán)境進行建模。景觀單元（或棱鏡）是一種工具，用于可視化和繪制地殼表面附近的有毒物質(zhì)循環(huán)。整個過程包含在GEOTOX代碼中，該代碼是一種地球化學系統(tǒng)模型，用于描述景觀中地殼毒素的動態(tài)以及由此產(chǎn)生的健康風險。 GEOTOX用于調(diào)查區(qū)域景觀對（'238）U，（'226）Ra，砷和鉛的土壤和巖石存量增加的響應(yīng)。已發(fā)現(xiàn)，每個衰變系列元素都通過其在整個環(huán)境中的行為而構(gòu)成危害，而這種毒性無法通過簡單的毒性度量來量化。 GEOTOX用于追蹤四種毒素的持續(xù)釋放直至穩(wěn)定狀態(tài)。結(jié)果提供了以g / km（'2）/ y（和Ci / km（'2）/ y）為單位的土壤或地下水源通量，導致人口癌癥風險每增加10（'-5）個人。對于鉛，相應(yīng)的血藥濃度設(shè)置為5 g / 100ml。 GEOTOX還用于對鈾系列從鈾礦體通過假想景觀的遷移所引起的風險場進行建模。本文介紹了沉積巖中鈾異常區(qū)的成因，為提出參考礦體奠定了基礎(chǔ)。

著錄項

  • 作者

    MCKONE, THOMAS EDWARD.;

  • 作者單位

    University of California, Los Angeles.;

  • 授予單位 University of California, Los Angeles.;
  • 學科 Environmental Sciences.
  • 學位 Ph.D.
  • 年度 1981
  • 頁碼 310 p.
  • 總頁數(shù) 310
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類 環(huán)境科學基礎(chǔ)理論;
  • 關(guān)鍵詞

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