Solid mine wastes can be dispersed in river systems by fluvial processes contaminating distant areas. This process has been previously reported in rivers of the Atacama Desert impacted by mining. The removal of waste in these rivers is a complex environmental scenario that involves (i) mining operation plans, (ii) the spatio-temporal variability of precipitation events and, (iii) the sediment-transport pathways within the drainage network. This work presents how flash floods triggered by extreme storm events determine the redistribution and the variation of elemental concentrations of the suspended load fraction in a river with several historical and actual mine wastes situated in the Atacama Desert. The concentrations of Cu, Pb, As and Hg measured in two sampling stations of a mining segment of the Copiapó River after flash floods are lower compared to the concentrations measured in the period before these hydrometeorological events. However, the concentrations of these metals and metalloids increased in areas distant from the mine clusters, where the values observed before the flash floods were lower. The redistributions of the element concentrations can be explained by the occurrence of two major flood events triggered by the extreme storm events of March 2015 and May 2017. The combination of the element concentrations with calculated geo-accumulation indexes shows the potential source of geochemical anomalies for these elements. Cu and Hg anomalies are induced by historical mining activities in the Copiapó River while Pb and As concentrations agree with the regional background. Some Pb and As anomalies would be associated with the geology of the zone where the main cluster of mine exploitations are present. The fact that flash floods result in Cu, Pb, As and Hg concentrations in sediment load more in line with the local background, suggests that this type of hydrometeorological events probably represent the natural processes of geochemical recovery of arid river impacted by metal mining.

固体矿山废物可以通过河流过程分散在河流系统中，从而污染遥远地区。先前曾在受采矿影响的阿塔卡马沙漠河流中报道过这一过程。这些河流中废物的清除是一个复杂的环境方案，涉及（i）采矿作业计划，（ii）降水事件的时空变化，以及（iii）排水网络内的泥沙输送路径。这项工作介绍了由极端风暴事件触发的山洪如何确定一条河流的悬浮负荷分数的元素分布和重新分布，以及在阿塔卡马沙漠中有一些历史和实际矿山废物的河流。铜，铅，暴发洪灾后在科皮亚波河采矿段的两个采样站测得的砷和汞含量低于这些水文气象事件发生前的浓度。但是，这些金属和准金属的浓度在远离矿区的区域增加，而在山洪暴发之前观测到的值较低。元素浓度的重新分配可以通过发生由2015年3月和2017年5月的极端风暴事件触发的两次主要洪灾事件来解释。元素浓度与计算出的地质累积指数的结合显示了潜在的地球化学异常源。这些要素。Cu和Hg异常是由Copiapó河中的历史采矿活动引起的，而Pb和As的浓度与区域背景一致。一些Pb和As异常可能与存在主要矿山开采区的区域的地质有关。暴发洪水导致沉积物中铜，铅，砷和汞的浓度更符合当地背景这一事实表明，这种类型的水文气象事件可能代表了受金属开采影响的干旱河流域地球化学恢复的自然过程。