The accumulation of heavy metals from sewage drainage in the estuary is not serious because of, partly, large silt discharge and high sedimentation rate.

河口重金属的积累，相对来说并不严重这与输沙量大及高沉积速率有关。

youdao

Last year 32m cubic metres of diluted sewage were dumped into the river, at a rate of roughly one discharge a week.

ECONOMIST: The capital's overflowing drains are due for a big upgrade