報告書番号

T87029

タイトル（和文）

石炭火力発電所排煙の土壌環境への影響評価

タイトル（英文）

EFFECT OF EMISSIONS FROM A COAL-FIRED POWER PLANT ON SOIL TRACE ELEMENT CONCENTRATIONS

概要 （図表や脚注は「報告書全文」に掲載しております）

２５年間の運転実績を有する石炭火力発電所を対象に，排煙中のばいじんとガス状物質が周辺土壌に沈着することにより，土壌中の元素（ヒ素，カドミウム，クロム，銅，水銀）がどの程度増加しているかを土壌調査と拡散計算により評価した。その結果，■発電所周辺の土壌中元素濃度は人為的影響が少ない地域（対照地域）の元素濃度とほぼ一致した。■富化判別係数で見た場合でも，採取地点が神社森林および公園の水銀の場合を除き，５元素とも対照地域の範囲内であった。■拡散計算により，発電所周辺土壌への各元素の沈着量を雨水等による流亡がないものとして推定した結果，２５年間の累積による各元素の富化判別係数の増加量は高くても０．２以下であった。この値は対照地域でのバラツキの範囲内であった。以上の結果，わが国で最も運転実績を有する石炭火力発電所においても，周辺土壌に沈着する元素量は僅かであり，識別できないレベルであると言える。

概要 （英文）

THE OBJECTIVE OF THIS STUDY WAS TO EVALUATE THE EFFECT OF TRACE ELEMENTS (AS,CD,CR,CU AND HG) EMITTED FROM A COAL-FIRED POWER PLANT ON THE SIOL ENVIRONMENT. A POWER PLANT THAT HAD BEEN OPERATED FOR 25 YEARS WAS SELECTED AS A REPRESENTATIVE PLANT FOR THIS STUDY. THE FOLLOWING WAS STUDIED IN THE VICINITY OF THE PLANT:(1)THE FIELD OBSERVATIONS OF THE ELEMENT CONCENTRATIONS IN SURFACE SOILS AND THE ENRICHMENT DISCRIMINATION FACTOR(EDF)WERE CARRIED OUT AT 30 SITES,AND(2)THE AMOUNT OF PARTICULATES DEPOSITED WAS ESTIMATED. THE EDF HAS BEEN PROPOSED BY SHIBUYA TO DISCERN THE EFFECT OF DEPOSITION OF PARTICULATES ON ELEMENT LEVELS IN SOIL,AND IS DEFINED AS THE RATIO OF ELEMENT CONCENTRATION IN SURFACE SOIL TO THAT IN DEEPER LAYERS OF SOIL. THE MAIN RESULTS ARE AS FOLLOWS: (1)THE ELEMENT CONCENTRATIONS IN SOIL AT 30 SITES WERE WITHIN THE RANGE OF THOSE OBSERVED AT BACKGROUND REGIONS IN JAPAN. (2)EDF S FOR THE 5 ELEMENTS WERE DISTRIBUTED IRREGULARLY WITHOUT ANY DEPENDENCE ON THE DISTANCE FROM THE PLANT,AND MOST OF THEM WERE WITHIN THERANGE OF EDF S OBSERVED IN BACKGROUND REGIONS. (3)INCREASES IN EDF CAUSED BY DEPOSITION OF PARTICULATES FOR 25 YEARS WERE ESTIMATED TO BE LESS THAN 0.2. FROM THESE RESULTS, IT CAN BE SAID THAT EVEN FOR THE POWER PLANT WHICH HAS BEEN OPERATED FOR THE LONGEST PERIOD IN JAPAN,THE AMOUNT OF ELEMENTS DEPOSITED WOULD NOT BE DETECTABLE LEVEL AND THAT THE EFFECT OF EMISSIONS ON THE SOIL ENVIRONMENT IS NEGLIGIBLE.

報告者

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