(1) pollution (or environmental pollution)

(2) Natural reasons: Taihu Lake has high water temperature, low water level and poor water fluidity in early summer.

Man-made reasons: industrial sewage, agricultural sewage and domestic sewage are discharged in large quantities, and the lake water has high nitrogen and phosphorus content and serious eutrophication.

(3) At the beginning of May 2007, the temperature in Wuxi was higher than normal, the floating time of cyanobacteria was advanced, the sunshine was sufficient, and the growth rate of cyanobacteria was accelerated; The precipitation is less, the water level in Taihu Lake is lower, and the concentration of nitrogen and phosphorus is higher. The southerly wind blows ahead of time, which makes cyanobacteria gather in Wuxi waters in the northwest ahead of time.

(4) Advantages: Biological purification of sewage by reeds and other vegetation fundamentally solves the problem of sewage treatment and discharge in Taihu Lake area.

Disadvantages: the transportation line is long, which requires a lot of manpower and material resources and needs to coordinate the forces of all parties.

This topic examines the problem of water resources.

(1) Eutrophication is a harmful phenomenon that human beings discharge sewage without restraint, which increases the concentration of nitrogen, phosphorus and other elements in the water body and leads to the rapid propagation of algae.

(2) The formation of eutrophication needs the cooperation of temperature, environment and other conditions besides the increase of the concentration of nutrients such as nitrogen and phosphorus. (3) For the eutrophication of Taihu Lake, the topic is to guide the analysis of the reasons, so it is mainly analyzed from the material.

(4) The evaluation needs dialectical analysis from both favorable and unfavorable aspects.