Angola is one of the countries with a high rate of waterborne diseases, due to the scarcity and poor quality of water for human consumption. The watercourses are receptors of many effluents, mainly domestic sewage, due to a precarious or inexistent sanitation system and a small number of wastewater treatment plants. Therefore, this study aims: (i) to evaluate the water quality (physicochemical and microbiological parameters) of three Angolan rivers (Kwanza, Bengo and Dande) in locations where water is used as drinking water or abstracted for human consumption; (ii) to develop a new water quality index able to quantitatively express the water quality in those sites; and (iii) to assess the spatial distribution of water pollution through principal component analysis (PCA).

Water quality assessment was performed by conducting four field surveys (campaigns I to IV); the first two campaigns took place in the dry season, while the last two ones took place in the rainy season. In the first two campaigns, the water quality was suitable to be treated for the production of drinking water, while in the last two campaigns, the water was unsuitable for that purpose (high levels of faecal coliforms were detected). The water quality index allowed to classify the water as generally excellent (campaigns I and II) and poor (campaigns III and IV). The rudimentary disinfection usually performed by individual water suppliers may improve the water quality, but it was not enough to achieve the parametric values required for human consumption in the rainy season (campaigns III and IV) except for Bengo sites. PCA identified sampling sites with the same water quality patterns, grouping into four groups (Kwanza sites) and two groups (Dande and Bengo sites). Therefore, the results of this study may support decision-makers as regards water supply management in the river stretches under study.

The new developed Water Quality Index can support decision-makers in terms of water supply management, especially in countries with a high rate of waterborne diseases (e.g. Angola).

安哥拉是水生疾病高发国家之一，原因是人类饮用水的稀缺性和劣质性。由于不稳定或不存在的卫生系统以及少量的废水处理厂，水道是许多废水（主要是生活污水）的接收器。因此，本研究的目的是：（i）在用水作为饮用水或取自人类的地方，评估三条安哥拉河流（宽扎，本戈和丹德）的水质（理化和微生物参数）；（ii）制定新的水质指数，以定量表示这些地点的水质；（iii）通过主成分分析（PCA）评估水污染的空间分布。

水质评估是通过进行四次现场调查（活动I至IV）进行的；前两个运动是在旱季进行的，而后两个运动是在雨季进行的。在前两个活动中，水质适合用于生产饮用水，而在后两个活动中，水不适合用于该目的（检测到高水平的粪便大肠菌群）。水质指数可将水分为一般优等（活动I和II）和差（广告系列III和IV）。通常由个别供水者进行的基本消毒可以改善水质，但除Bengo场所外，它还不足以达到雨季（活动III和IV）人类食用所需的参数值。PCA确定了具有相同水质模式的采样点，分为四个组（宽扎站点）和两个组（Dande和Bengo站点）。因此，这项研究的结果可以为决策者在所研究的河流中的供水管理方面提供支持。

新制定的《水质指数》可以在供水管理方面为决策者提供支持，特别是在水传播疾病发生率很高的国家（例如安哥拉）中。