Sonkar Vikas, Sasidharan Sai Sugitha, Jambu Sangeetha Chandrakalabai, Rengan Aravind Kumar, Kreft Jan-Ulrich, Thatikonda Shashidhar
One Health Research, Environmental Engineering, Department of Civil Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502284, Telangana, India.
Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502284, Telangana, India.
Environ Res. 2025 Oct 1;282:121996. doi: 10.1016/j.envres.2025.121996. Epub 2025 Jun 2.
Freshwater bodies are often polluted by municipal wastewater discharges that degrade water quality while current river monitoring focuses primarily on physical and chemical parameters, neglecting ecosystem health assessments. Hence, this study uses zebrafish (Danio rerio) as a model organism to evaluate the ecotoxicological effects of wastewater contamination in the Musi River catchment with urban and rural land use. The river receives a combination of inputs from reservoirs, treated and untreated urban wastewater, industrial discharges, and agricultural runoff. Sampling locations were selected from upstream, within the city, and downstream stretches to assess the effects of these diverse pollution sources. Zebrafish embryos and larvae, exposed for up to 96 h post-fertilization (hpf) to water samples from the urban stretch, exhibited high mortality, delayed hatching, and increased teratogenicity. Significant effects on heart rate and cellular apoptosis were observed, while histopathological analysis revealed muscle disorganization, notochord malformation, yolk sac defects, and delayed eye and brain development at 96 hpf. Notably, water from the downstream site, despite lower pollution levels, still led to persistent tissue alterations. Most toxicity indicators differed significantly between stretches. Independent clustering of water quality and toxicity parameters separated stretches identically while linear discriminant analysis based on water quality parameters could classify the stretches with their contrasting toxicity. This study made comprehensive use of multiple biomarkers to assess river pollution typical for cities in developing nations. The findings demonstrate the potential of the Zebrafish Embryo-Larval Toxicity Test (ZELT) as an effective vertebrate model for ecological toxicity assessment of freshwater bodies worldwide.
淡水水体常常受到城市污水排放的污染，这会降低水质，而目前的河流监测主要集中在物理和化学参数上，忽视了生态系统健康评估。因此，本研究以斑马鱼（Danio rerio）作为模式生物，评估穆西河集水区城乡土地利用中废水污染的生态毒理效应。该河流接收来自水库、经处理和未经处理的城市污水、工业排放以及农业径流的综合输入。采样地点选自在上游、城市范围内以及下游河段，以评估这些不同污染源的影响。受精后长达96小时（hpf）暴露于城市河段水样中的斑马鱼胚胎和幼体，表现出高死亡率、孵化延迟和致畸性增加。观察到对心率和细胞凋亡有显著影响，而组织病理学分析显示在96 hpf时存在肌肉紊乱、脊索畸形、卵黄囊缺陷以及眼睛和大脑发育延迟。值得注意的是，下游地点的水尽管污染水平较低，但仍导致持续的组织改变。大多数毒性指标在不同河段之间存在显著差异。水质和毒性参数的独立聚类以相同方式区分了不同河段，而基于水质参数的线性判别分析能够根据其不同的毒性对各河段进行分类。本研究全面利用多种生物标志物评估了发展中国家城市典型的河流污染情况。研究结果证明了斑马鱼胚胎 - 幼体毒性试验（ZELT）作为全球淡水水体生态毒性评估的有效脊椎动物模型的潜力。
