水道中のハロゲン化消毒副生成物  [in Japanese] Halogenated Disinfection By-Products in Tap Water  [in Japanese]

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Abstract

河川水を原水とした水道水では総ハロゲン化消毒副生成物濃度は冬季に最低値 (50μg/l弱) を示した後, 徐々に増加し, 8月に最高値 (200μg/l強) を示した。ハロゲン化消毒副生成物を類別に見ると, ハロ酢酸, トリハロメタンはメジャー成分であり, ハロアセトアルデヒド, ハロアセトニトリル, ハロアセトンは中間成分であり, ハロプロピオン酸, ハロニトロメタンはマイナー成分であった。なお, 中間成分ではハロアセトアルデヒド濃度は必ずハロアセトニトリルより高かった。個々のハロゲン化消毒副生成物を見ると, トリハロメタンではクロロホルムは明白に季節変動を示し, プロモジクロロメタン, ジブロモクロロメタン, プロモホルムの順に濃度は極端に低くなっていた。ハロアセトニトリルではメジャー成分であるジクロロアセトニトリルは季節変動を示し, マイナー成分であるプロモクロロアセトニトリル, ジブロモアセトニトリルは一年中ほぼ一定であった。ハロアセトンではメジャー成分である1, 1, 1-トリクロロアセトンは季節変動を示し, マイナー成分である1, 1-ジクロロアセトンは全く季節変動を示さなかった。ハロアセトアルデヒドではメジャー成分であるトリクロロアセトアルデヒドは季節変動を示したが, マイナー成分であるジクロロアセトアルデヒドは季節変動を示さなかった。ハロ酢酸ではメジャー成分としてジクロロ酢酸, 中間成分としてトリクロロ酢酸, マイナー成分としてプロモクロロ酢酸, ジクロロブロモ酢酸等であった。ハロプロピォン酸では多くは2, 2-ジクロロプロピオン酸, 一部2, 3-ジクロロプロピオン酸であった。<BR>地下水を混合した水道水では総ハロゲン化消毒副生成物濃度は冬季, 夏季で二分し, 約100μg/l~約200μg/lである場合と, 季節間の差が認められず100μg/l弱~約150μg/l強である場合があった。中間成分のハロアセトアルデヒド濃度がハロアセトニトリルより低かった以外では, ハロゲン化消毒副生成物の類別量の順位は河川水を原水とした水道水と同じであった。河川水を原水とした水道水中の個々のハロゲン化消毒副生成と比較して, トリハロメタンではプロムを含有したトリハロメタンが増加し, ハロアセトニトリルではジブロモアセトニトリル, ハロアセトアルデヒドではトリブロモアセトアルデヒド, ハロ酢酸ではジブロモクロロ酢酸が高い濃度で検出されていた。逆に濃度が低かった副生成物としてジクロロ酢酸がある。<BR>高度処理を施した水道水では総ハロゲン化消毒副生成物濃度は季節間の差が認められず, 約50μg/l~約100μg/lの濃度であった。ハロゲン化消毒副生成物の類別量の順位は地下水を混合した水道水と同じであった。そして, 河川水を原水とした水道水中の個々のハロゲン化消毒副生成物と比較して, 全てのハロゲン化消毒副生成物の濃度は低かった。<BR>同一水道水を供給されても, 受水槽・高置水槽を経由した水道水は水道本管からの水道水に比較して, 総ハロゲン化消毒副生成物の濃度は高く, また受水槽・高置水槽中の滞留時間の長い水道水程, 総ハロゲン化消毒副生成物の濃度は高かった。今回調査した受水槽・高置水槽は比較的密閉状態であったので, ハロアセトン以外の類別ハロゲン化消毒副生成物, 及び類別のメジャー成分である個々のハロゲン化消毒副生成物も滞留時間の増加, 即ち有効残留塩素の接触時間に相関して増加していた。

In tap water derived from river water, the total concentration of all halogenated disinfection by-products was the lowest (slightly less than 50μg/l) during winter but gradually increased, reaching a peak (slightly over 200μg/l) in August. According to the classes of halogenated by-products, haloacetic acids and trihalomethanes were major by-products, haloacetaldehydes, haloacetonitriles and haloacetones were medium by-products, and halopropionic acids and halonitromethanes were minor by-products. Among the medium by-products, the haloacetaldehydes concentration was always higher than haloacetonitriles concentration. Evaluation of individual halogenated by-products in each class revealed the following findings. In trihalomethanes, the concentration of chloroform was the highest, showing clear seasonal variation while that of other by-products was low, markedly decreasing in the order of bromodichloromethane, dibromochloromethane, and bromoform. In haloacetonitriles, dichloroacetonitrile as a major by-product showed seasonal variation while bromochloroacetonitrile and dibromoacetonitrile as minor by-products showed nearly constant concentration during the year. In haloacetones, seanonal variation was observed in 1, 1, 1-trichloroacetone (a major by-product) but not 1, 1-dichloroacetone (a minor by-product) . In haloacetaldehydes, seasonal variation was observed in trichloroacetaldehyde (a major by-product) but not in dichloroacetaldehyde (a minor by-product) . In haloacetic acids, dichloroacetic acid was a major by-product, trichloroacetic acid was a medium by-product, and bromochloroacetic acid and dichlorobromoacetic acid were minor by-products. In halopropionic acids, 2, 2-dichloropropionic acid was a major by-product, and 2, 3-dichloropropionic acid was a minor by-product.<BR>In tap water derived from the mixture of river water and ground water, the total concentration of all halogenated by-products was low in winter and high in summer (about 100-200μg/l) fiein some samples but showed no seasonal variation (slightly less than 100 -slightly more than 150μg/l) in others. The order of the concentrations of the halogenated by-product classes was similar between the tap water derived from the mixture of river water and ground water and that derived from river water except that the haloacetaldehydes concentration was lower than the haloacetonitriles concentration in the former. Compared with individual halogenated by-products in the river water-derived tap water, trihalomethane cantaining bromine atom increased in trihalomethanes, dibromoacetonitrile in haloacetonitriles, tribromoacetaldehyde in haloacetaldehydes, and dibromochloroacetic acid in haloacetic acids while the dichloroacetic acid concentration decreased.<BR>Tap water after advanced water treatment showed no seasonal variation in the total concentration of halogenated by-products (about 50-100μg/l) . The concentration order of the classes of halogenated by-products in this tap water was the almost same as that in the tap water derived from a mixture of river water and ground water. The concentrations of all individual halogenated by-products were lower in this tap water than in the river water-derived tap water.<BR>Even when the same tap water was supplied, the tap water via the water receiving tank elevated tank showed a higher total concentration of halogenated by-products than the tap water from main supply tube directly. In addition, the total concentration of halogenated by-products was higher in the water kept in receiving tank elevated tank for a longer period. Since the water receiving tank/elevated tanks investigated in this study were in a relatively sealed state, the concentrations of all classes of halogenated by-products except haloacetones and major halogenated by-products in each class showed good correlation with the residence time of the water in the tanks, i.e., the time of contact with effective residual chlorine.

Journal

  • Journal of Environmental Chemistry

    Journal of Environmental Chemistry 8(3), 455-464, 1998-09-17

    Japan Society for Environmental Chemistry

References:  15

Cited by:  5

Codes

  • NII Article ID (NAID)
    10009671570
  • NII NACSIS-CAT ID (NCID)
    AN10547099
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    09172408
  • NDL Article ID
    4572251
  • NDL Source Classification
    ZN5(科学技術--建設工学・建設業--都市工学・衛生工学) // ZP1(科学技術--化学・化学工業)
  • NDL Call No.
    Z16-2322
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
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