source of sediment

例句：

1. 1. The river is a major source ofsediment for the nearby cities.
   这条河流是附近城市的主要沉积物来源。
2. 2. The study foundthat the source of the pollution was fromthe factory.
   研究发现，污染的来源是工厂。
3. 3. Thescientist used a microscope to observe the sourceof the bacteria in the sample.
   科学家使用显微镜观察样本中细菌的来源。