[Retention Effect of Heavy Metals in Rivers of a Typical Mountainous City by Cascade Weirs: A Case Study of Liangtan River in Chongqing].

Contaminants such as heavy metals in rivers are partially retained in the sediments at the bottom as a result of the altered water regime within the cascade weirs. The associated heavy metals in the sediments can affect surface water quality and ecology for a long period. In May 2020, sediments were collected in a typical mountainous river (Liangtan River) with cascade weirs in the main urban area of Chongqing.