Freie Universität Berlin, Berlin, Germany.
Goethe-Universität Frankfurt, Frankfurt, Germany.
Environ Monit Assess. 2024 Apr 17;196(5):456. doi: 10.1007/s10661-024-12613-2.
The increasing pressure on freshwater systems due to intensive anthropogenic use is a big challenge in central-northern Namibia and its catchment areas, the Kunene and the Kavango Rivers, and the Cuvelai-Etosha Basin, that provide water for more than 1 million people. So far, there is no comprehensive knowledge about the ecological status and only few knowledge about the water quality. Therefore, it is crucial to learn about the state of the ecosystem and the ecological effects of pollutants to ensure the safe use of these resources. The surface waters of the three systems were sampled, and three bioassays were applied on three trophic levels: algae, daphnia, and zebrafish embryos. Additionally, in vitro assays were performed to analyze mutagenicity (Ames fluctuation), dioxin-like potential (micro-EROD), and estrogenicity (YES) by mechanism-specific effects. The results show that acute toxicity to fish embryos and daphnia has mainly been detected at all sites in the three catchment areas. The systems differ significantly from each other, with the sites in the Iishana system showing the highest acute toxicity. At the cellular level, only weak effects were identified, although these were stronger in the Iishana system than in the two perennial systems. Algae growth was not inhibited, and no cytotoxic effects could be detected in any of the samples. Mutagenic effects and an estrogenic potential were detected at three sites in the Iishana system. These findings are critical in water resource management as the effects can adversely impact the health of aquatic ecosystems and the organisms within them.
由于人类的密集使用，淡水系统承受的压力不断增加，这对纳米比亚中北部及其集水区（库内内河和卡万戈河以及库鲁伯里-埃托沙盆地）构成了巨大挑战。这些集水区为超过 100 万人提供了水源。迄今为止，人们对该地区的生态状况没有全面的了解，对水质的了解也很少。因此，了解生态系统的状况以及污染物的生态影响对于确保这些资源的安全利用至关重要。本研究对三个系统的地表水进行了采样，并在三个营养水平上应用了三种生物测定法：藻类、水蚤和斑马鱼胚胎。此外，还进行了体外试验，通过特定机制的效应来分析致突变性（Ames 波动）、类二恶英潜力（微量 EROD）和雌激素活性（YES）。结果表明，在三个集水区的所有地点都主要检测到了对鱼类胚胎和水蚤的急性毒性。这三个系统之间存在显著差异，伊希纳系统的各个地点表现出的急性毒性最高。在细胞水平上，虽然在伊希纳系统中观察到的效应比在两个常年系统中更强，但只识别出了较弱的效应。藻类生长没有受到抑制，在任何样本中都没有检测到细胞毒性效应。在伊希纳系统的三个地点检测到了致突变效应和雌激素潜力。这些发现对水资源管理至关重要，因为这些效应会对水生生态系统及其内部的生物健康产生不利影响。
