River damming has numerous benefits and adverse consequences. Unlike large dam reservoirs whose construction peaked in the twentieth century, historical ponds and their accumulated legacy sediments span much longer time periods. Small ponds in many areas worldwide are sinks for anthropogenic pollutants and affect sediment delivery to downstream river reaches. Thousands of ponds cover an area of >0.2 % of the territory of Czechia, equal to the area of its ten largest dam reservoirs. This paper reports a sequence of constructed and removed pond dams along the Vrchlice River, Czechia, and their use as sedimentary archives, in order to reconstruct the long-term (>200 yr) history of contamination. Historical maps, geophysical profiles, activities of caesium-137 isotope, grain size, and sediment geochemistry in 16 sediment cores enabled the reconstruction of contamination in the pond, dam reservoir, and floodplain sediments since ∼1780. Contamination by lead, copper, zinc, arsenic, and cadmium from atmospheric, geogenic and agricultural sources increased since ∼1850 peaked in the 1970s and 1980s, and then decreased slightly. Polycyclic aromatic hydrocarbons and pesticides polluted post-1970 sediments, reflecting their use in agriculture. The removal of dams resulted in the rapid incision of newly formed river channels into the old pond deposits. Following the reinstatement of dams, channels filled rapidly (up to 5.2 cm/yr) with new lacustrine sediment, whereas sediment accumulated slowly (<0.4 cm/yr) outside the channels. Upon dam removal, contaminated channel-fill sediment likely redistributed into the water course. As ponds are complex depositional systems with the heterogeneous distribution of sediment and associated contaminants, active and extinct ponds are promising long-term sedimentary archives that can extend understanding of human interactions with Earth systems.

筑坝有许多好处和不利后果。与大型水库的建设在20世纪达到顶峰不同，历史悠久的池塘及其累积的沉积物跨越了更长的时间。世界各地许多地区的小池塘都是人为污染物的汇，影响到下游河流沉积物的输送。成千上万的池塘占捷克共和国领土的0.2％以上，相当于其十个最大的水库的面积。本文报告了德意志共和国Vrchlice河沿岸一系列建造和拆除的池塘水坝及其作为沉积档案的用途，以重建污染的长期历史（> 200年）。历史地图，地球物理剖面，铯137同位素的活动，晶粒大小，自1780年以来，通过16个沉积物核心的沉积物地球化学和沉积物，得以重建了池塘，大坝水库和洪泛区沉积物中的污染物。自1970年代和1980年代的1850年达到峰值以来，来自大气，地质和农业来源的铅，铜，锌，砷和镉的污染有所增加。多环芳烃和农药污染了1970年以后的沉积物，反映出它们在农业中的使用。水坝的拆除导致新形成的河道迅速切入旧池塘沉积物中。在恢复水坝之后，河道迅速（至5.2厘米/年）充满了新的湖相沉积物，而河道外的沉积物则缓慢地堆积（<0.4厘米/年）。拆除大坝后，受污染的河道填充物可能会重新分配到水道中。