パルプ, 紙製造工場による環境汚染 : 燧難東部および琵琶湖大津沖における底質汚染の事例

Abstract

パルプ, 紙製造工場の排水による付近の海洋, 湖沼の底質に与える影響に関して, 燧灘東部および琵琶湖大津沖において, その実態調査をおこなった。その結果 1 燧灘東部においては, 紙パ工場地帯沿岸を中心として, 底質のCODがきわめて高く, 有機物による汚染が顕著である。さらに汚染面積 (COD 30mg/g以上) の拡がりの傾向は, 同地域の紙パ生産量の伸びとよく対応している。重金属の蓄積については, 特に銅と亜鉛が, 工場地帯を中心に高まりがみられた。2 琵琶湖大津沖においても, 板紙工場排水口を中心として, 強熱減量値が大きな値をしめし, 有機物が大量に沈積している。各種重金属も工場付近で高い蓄積がみられた。原料故紙のなかに含まれる感圧紙によるとみられるPCB汚染が顕著で, 飲料水に対する影響が憂慮される。

This investigation was undertaken to find out the influence of the waste from pulp and paper factories on the bottom deposits in the east area of Sea of Hiuchi and in the off-Ohtsu area of Lake Biwa. The conclusions are as follows. 1. In the east area of Sea of Hiuchi, the COD values of bottom deposits are very high along the coast of the factory region of pulp and paper industries and the polluted area (COD > 30mg/g) has expanded as wide as 40km2. Such expansion of the polluted area corresponds well with the growth of production in the pulp and paper industries. As for the accumulation of heavy metals, higher concentrations of copper and zinc than normal were detected throughout the area investigated with the highest value at the factory region. 2. In the offshore area of Ohtsu of Lake Biwa, increased values of ignition loss were observed with a board factory as the center of the increase. Various heavy metals have also accumulated a great deal in the area close to the factory. An evident PCB pollution was found there and this PCB pollution is thought to have been caused by non-carbon paper contained in the waste paper, the material of the board. The authors are concerned about the influence of this pollution on drinking water.