Landner L, Grahn O, Härdig J, Lehtinen K J, Monfelt C, Tana J
European Environmental Research Group, MFG-Sweden, Stockholm.
Ecotoxicol Environ Saf. 1994 Mar;27(2):128-57. doi: 10.1006/eesa.1994.1012.
The rate of technical development in bleaching of chemical pulp and the upgrading of process control and wastewater treatment systems in the pulp industry have been extremely rapid over the past few years. When assessing the environmental impacts of bleached kraft pulp mill effluents (BKMEs), it is therefore more important than ever to carefully characterize the bleaching process, the composition of the treated effluent, and the degree of exposure of sensitive target organisms in the receiving water body. These requirements have not always been fulfilled in previous reports on biological effects of BKMEs in Scandinavia. This work presents the results of a comprehensive field study of the impacts of a 350,000-tonne kraft mill, bleaching softwood and hardwood pulp in campaigns according to the sequence O(D25,C70+D5)(EOP)D(EP)D. The effluent is treated in an aerated lagoon with a mean retention time of 8-9 days, practically eliminating chlorate and resin acids, and reducing the discharge of adsorbable organic halogen (AOX) to an average of 1 t/day (1.3 and 0.4 kg/ADt for softwood and hardwood, respectively). The treated effluent is discharged through a 1.3-km-long diffuser, at a water depth of 9-12 m, into a well ventilated coastal area, giving a 1000-fold dilution within 3-4 km from the diffuser. The actual exposure of the coastal ecosystem to BKME components was determined by analysis of extractable organic chlorine in suspended solids and of conjugates of chlorophenolics in the bile of feral perch. Despite a major damage to the benthic communities that occurred about 10 years ago, and was due to large chlorate discharges at the time, no direct detrimental effects on benthic flora and fauna could be ascribed to the present BKME discharge. Instead, a clear recovery of the Fucus community, although not yet completed, could be demonstrated. Studies of the composition, abundance and biomass of the fish community, the recruitment and survival of fish fry, and the physiological status of perch, using a set of biomarkers, revealed that even in the most BKME-exposed area, only minor effects were detected. These effects were related to eutrophication/enrichment rather than to the action of toxic substances. The general effect picture, thus, was essentially of a different type than the one recorded in previous studies of mills, which used older technology and less effective process and effluent treatment control, and which were discharging into enclosed, shallow bays of the Baltic Sea.
在过去几年中，化学浆漂白技术的发展速度以及制浆行业过程控制和废水处理系统的升级速度都极快。因此，在评估漂白硫酸盐浆厂废水（BKMEs）对环境的影响时，仔细描述漂白过程、处理后废水的成分以及受纳水体中敏感目标生物的暴露程度比以往任何时候都更加重要。在斯堪的纳维亚半岛以往关于BKMEs生物效应的报告中，这些要求并非总能得到满足。这项工作展示了一项全面的实地研究结果，该研究针对一家年产35万吨的硫酸盐制浆厂，按照O(D25,C70+D5)(EOP)D(EP)D的流程对针叶木浆和阔叶木浆进行漂白。废水在曝气塘中处理，平均停留时间为8 - 9天，几乎消除了氯酸盐和树脂酸，并将可吸附有机卤化物（AOX）的排放量降低至平均每天1吨（针叶木和阔叶木分别为1.3千克/绝干吨和0.4千克/绝干吨）。处理后的废水通过一条1.3千米长的扩散器，在水深9 - 12米处排放到通风良好的沿海区域，在距离扩散器3 - 4千米范围内实现了1000倍的稀释。通过分析悬浮固体中的可提取有机氯以及野生鲈鱼胆汁中氯酚类化合物的共轭物，确定了沿海生态系统对BKME成分的实际暴露情况。尽管大约10年前曾因当时大量排放氯酸盐对底栖生物群落造成了重大破坏，但目前的BKME排放并未对底栖动植物产生直接有害影响。相反，可以证明墨角藻群落正在明显恢复，尽管尚未完成。使用一组生物标志物对鱼类群落的组成、丰度和生物量、鱼苗的补充和存活以及鲈鱼的生理状态进行研究后发现，即使在BKME暴露最严重的区域，也仅检测到轻微影响。这些影响与富营养化/富集有关，而非与有毒物质的作用有关。因此，总体影响情况与以往对采用旧技术且过程和废水处理控制效果较差、废水排放到波罗的海封闭浅湾的工厂的研究记录基本不同。
