In the European Union the basic requirements in the subject of the appropriate quality of water, constituting a habitat for fish, was established in Directive 2006/44/EC (EU, 2006) on the quality of fresh waters needing protection or improvement in order to support fish life (currently implicitly repealed by Directive 2000/60/EC). This legislation presents the list of parameters that should be controlled together with their guide and mandatory levels, methods of analysis as well as minimum sampling and measuring frequency. Based on the case study from the Podhale region in southern Poland, the impact of used geothermal water discharge on river water quality was assessed, in particular in the context of the quality of the life of salmonid fish species. The variability of the chemical composition of river water as a result of used geothermal water discharge was assessed both in statistical terms and in correlation to river flows. To quantify the water quality in terms of protection of the fish life, a new Fish-Water Pollution Index was developed. In the presented case, similarly to the Water Quality Indices and Heavy Metal Pollution Indices, also the Fish Water Pollution Indices values calculated upstream and downstream of the used geothermal water discharge, do not display significant differences.

在欧盟，第2006/44 / EC号指令（欧盟，2006年）就需要保护或改善淡水质量的基本要求建立了构成鱼类栖息地的适当水质这一基本要求。支持鱼类的生命（目前已被2000/60 / EC指令暗中废除）。该立法提出了应控制的参数清单以及其指导和强制性水平，分析方法以及最小采样和测量频率。根据波兰南部Podhale地区的案例研究，评估了用过的地热水排放对河水水质的影响，特别是在鲑鱼鱼类生活质量方面。用统计学术语以及与河流流量的关系，评估了用过的地热水排放后河水化学成分的变化。为了从保护鱼类生命的角度量化水质，开发了新的鱼类-水污染指数。在本案例中，类似于水质指数和重金属污染指数，所用地热水排放量的上游和下游计算出的鱼水污染指数值也没有显着差异。