| environ. |
eutrophication A process of pollution that occurs when a lake or stream becomes over-rich in plant nutrient; as a consequence it becomes overgrown in algae and other aquatic plants. The plants die and decompose. In decomposing the plants rob the water of oxygen and the lake, river or stream becomes lifeless. Nitrate fertilizers which drain from the fields, nutrients from animal wastes and human sewage are the primary causes of eutrophication. They have high biological oxygen demand (BOD) (湖泊或水流过多含有植物营养物质而被污染的过程；其结果是过度生长出藻类和其他水生植物。植物死亡和分解。分解过程中，植物吸取水中的氧气，使得湖泊，河流和水流变得无生命。由田间排放的硝酸盐肥料，动物粪便和人类排泄物中的养分是富营养化的主要原因。他们有很高的氧气需求。) |
