The most populous city of the world’s largest watershed (Manaus, Amazon Basin, Brazil) is experiencing an extensive urban expansion since the early 1970s, with an attendant cost in environmental degradation. The upland area of the Manaus municipality is characterized by several streams. In this work, we aim to gradually measure the anthropogenic effect on water quality: we monitored three streams flowing over three zones: a preserved (where the streams take source), a peri-urban (where rural and leisure activities occur), and an urban area. From June 2013 to May 2015, we characterized the water quality of these streams. Statistical analyses reveal peri-urban activity does not significantly impact the water quality. Indeed, when the disturbance remains space-, time- and intensity-limited, the streams have the capacity to assimilate the anthropogenic pollution. However, looking at a seasonal finer scale, peri-urban activity slightly affects the natural pattern of water quality, but these changes remain moderated when compared to the original pattern of water quality. Over urban area, the water quality presents significant higher alkalinity, mineralization, turbidity, suspended material, biochemical and chemical oxygen demands, and lower acidity and dissolved oxygen. These alterations originate with sewage deficiency, presence of landfill sites, enhanced leaching of upturned soil and domestic waste. The natural seasonal patterns of water quality are totally disturbed (inversion, intensification) in the urban area. During the wet season, enhanced rainfall in conjunction with human activity generates local seasonal processes of dilution (e.g. negative anomalies for most of the dissolved elements) and concentration (positive Mg and Fe anomalies). The latter can be linked with enhanced leaching during the rainy period (positive Mg and Fe anomalies) and nitrification activity in the urban area (positive NO₃ and negative NH₄ anomalies).

自1970年代初以来，世界上最大的流域中人口最多的城市（马瑙斯，巴西亚马逊河流域）正经历着大规模的城市扩张，随之而来的环境退化代价也很高。玛瑙斯市的高地地区有几条溪流。在这项工作中，我们旨在逐步衡量人为因素对水质的影响：我们监测了三个区域上流过的三股水流：一个保留区（水流源于此），一个城市周边地区（农村和休闲活动在其中发生）以及一个市区。从2013年6月到2015年5月，我们对这些溪流的水质进行了表征。统计分析表明，城市周边的活动不会显着影响水质。确实，当干扰仍然受到空间，时间和强度的限制时，溪流具有吸收人为污染的能力。但是，从季节性更精细的角度来看，城市周边的活动对水质的自然形态有轻微的影响，但是与原始水质形态相比，这些变化仍然适度。在城市地区，水质表现出较高的碱度，矿化度，浊度，悬浮物，生化和化学需氧量，以及较低的酸度和溶解氧。这些变化源于污水缺乏，垃圾填埋场的存在，上层土壤和家庭垃圾浸出的增加。在城市地区，水质的自然季节性模式完全受到干扰（反演，集约化）。在雨季 降雨增加以及人类活动会导致局部季节性的稀释过程（例如，大多数溶解元素的负异常）和浓度（镁和铁正异常）。后者可能与雨季淋溶增强（Mg和Fe异常阳性）和城市地区的硝化作用（NO阳性）有关。₃和负NH ₄异常）。