sediment
noun uk/ˈsed.ɪ.mənt/ us/ˈsed.ə.mənt/
[ C or U ]沉淀物，沉渣
a soft substance that is like a wet powder and consists of very small pieces of a solid material that have fallen to the bottom of a liquid
There was a brown sediment in the bottom of the bottle. 瓶子底部有褐色的沉淀物。
sediments [ plural ] 沉积物（最终形成一层岩石的砂子、石头等）
sand, stones, etc. that slowly form a layer of rock
It is hoped that the oil slick will sink to the seabed where it would be covered within a few years by sediments and eventually decompose. 人们希望浮油会沉到海底，并且在数年内被沉积物覆盖，最终分解。
The sediments from four polluted sites in the region were collected for analysis.
In the early Cambrian, this area was dominated by clastic sediments.
The advocacy group is calling for the removal of these contaminated sediments from the watershed.
It is feared that sea-floor sediments as deep as 1000 metres might be affected by the tanker spill.