The aim of this study was to use an integrated, multi-indicator approach to assess and compare the biotic integrity of the polluted rivers flowing into the hyper-eutrophic Roodeplaat Dam. This included seasonal assessments of physical, chemical and biological parameters of the water and sediment, as well as a habitat, macro-invertebrate and histology-based fish health assessment. The results showed that all three rivers are polluted by metals and faecal coliform bacteria and high nutrient levels which explains the eutrophic status of the receiving impoundment. The Edendalespruit showed higher metal concentrations while the Pienaars River showed higher nutrients and Chlorophyll-a levels. Semi-volatile organic compounds were detected in sediment samples from all three rivers. The macroinvertebrate assessment confirmed that the water quality of the rivers are negatively impacted with most of the sites classified as “fair” to “poor” based on the number of taxa identified and their sensitivity scores. The histological assessment of six different target organs of two indicator fish species indicated a definite tissue response, especially in terms of the liver alterations in Clarias gariepinus. The percentage prevalence of alterations varied across rivers and seasons with no discernible pattern identified. The assessment of both abiotic and biotic indicators indicated that this system is plagued by a number of negative impacts and that management initiatives should focus especially on the activities influencing the Pienaars River to mitigate the continuing eutrophication of the Roodeplaat Dam.

这项研究的目的是使用一种综合的，多指标的方法来评估和比较流入富营养化Roodeplaat大坝的被污染河流的生物完整性。这包括对水和沉积物的物理，化学和生物学参数的季节性评估，以及栖息地，大型无脊椎动物和基于组织学的鱼类健康评估。结果表明，这三条河流均被金属，粪便大肠菌和高营养水平污染，这解释了接收蓄水池的富营养化状态。Edendalespruit的金属浓度较高，而Pienaars河的营养液和叶绿素a较高。水平。在所有三条河流的沉积物样本中检测到半挥发性有机化合物。大型无脊椎动物评估证实，河流的水质受到负面影响，根据识别出的分类单元数量及其敏感性得分，大多数站点被归类为“一般”至“差”。对两种指示性鱼类的六个不同目标器官的组织学评估显示了明确的组织反应，特别是就Clarias gariepinus的肝脏变化而言。跨河流和不同季节的变化发生率不同，没有发现可辨别的模式。对非生物和生物指标的评估表明，该系统受到许多负面影响的困扰，管理举措应特别着重于影响Pienaars河的活动，以减轻Roodeplaat大坝的持续富营养化。