Due to the diffusional effect, the pollutant will flow not only towards the down-stream, but also in other directions, including the direction against the flow stream.

因为污染物除随河水流动方向流动以外，还会向河水流动不同方向扩散。污染物也可能由于水体的自净作用而在流动过程中逐渐消失。

youdao

Due to the diffusional effect, the pollutant will flow not only towards the down-stream, but also in other directions, including the direction against the flow stream.

因为污染物除随河水流动方向流动以外，还会向河水流动不同方向扩散。污染物也可能由于水体的自净作用而在流动过程中逐渐消失。

youdao