Toxicity of As on Soil Neutral Phosphatase

摘要

Toxicity of As on soil neutral phosphatase was studied through a series indoor incubation experiments. Results showed that the activity of soil neutral phosphatase was significantly inhibited by As pollution, and the peak inhibiting ratio was appeared at the sixth incubation day. While the activity of soil neutral phosphatase was also decreased with concentration of As increasing in the same incubation day. The relationship between the concentration of as and soil neutral phosphatase was fit by model ①y＝c/(1＋bx) and ②y＝c(1＋ax)(1＋bx). The model ② was more suitable to describe the relationship between the concentration of As and soil enzyme. This means the effect mechanism of As on the soil neutral phosphatase was part of inhibition. The Km of neutral phosphatase was increase by As concentration adding, while the V_(max) was lowered. This kind of inhibition belongs to mix competition inhibition.