[Degradation of phthalate esters in soil and the effects on soil enzyme activities]

Phthalate esters (PAEs) are a kind of widespread toxic organic compounds in the environment. We discussed the different degradation rate of four kinds of PAEs in the soil and its impact on different soil enzyme activities. We used GC-MS methods to determine the concentration of PAEs in soil. The results showed that soil microorganisms play a major role in the degradation of PAEs. The biodegradation diagram of PAEs was accord with first-order kinetics equation. And the shorter carbon chain, the better degradation efficiency. With the high concentration of PAE30, DnOP, which has long carbon chain, the degradation efficiency is lower than that of PAE1 and PAE10, only 73% was degraded after 40 days. We use standard methods to determine the matrix enzyme activities, after adding the PAEs into soil, beta-glucosidase, phosphatase, urease, protease activity have changed. Phosphatase activity decreased at first and then increased, beta-glucosidase activity decreased slowly, protease activity increased at first and then decreased, the activity of urease increased gradually. After 20 days, except for beta-glucosidase activity continued decreasing, the activities of others enzyme recovered gradually, and higher than the control group.