菲对土壤酶活性的影响

Effects of Phenanthrene Contamination on Enzyme Activity in Soil

采用室内培养方法,选择菲作为PAHs代表物,探讨了菲与土壤酶活性之间的关系。结果表明,当菲的添加浓度>100μg·kg-1时,添加菲后的3d时间里,土壤中脲酶活性有被抑制的现象;添加菲后的7d时间里,土壤中脱氢酶活性被抑制,土壤磷酸酶的活性却被激活;当菲的添加浓度为100～2400μg·kg-1时,土壤过氧化氢酶活性没有显著变化。土壤脲酶、脱氢酶、磷酸酶的活性可以作为菲污染土壤的生态毒理指标,并且观察它们在添加菲后的第1d到第7d的变化最为重要。

Soil enzymes play important role in circle of carbon, nitrogen and phosphorus, which are concerned with metabolic processes in soil system, such as soil occurrence and development, fertility formation in soil, nutrition materia l transformation, organic matter decomposing, contaminations degradation and so on. Soil enzyme activity can reflect intensities and directions of many biochem ical processes, and is affected by those lots of environmental factors are physi cal, chemical, biological ingredient and so on. Therefore, soil enzyme activity can be considered as a kind of eco-toxicological indicators that assess contam inative degree and effects of external materials on soil entironment that. PAHs' toxicity and carcinogenic characteristics have been paid attention to human att aches gradually. Phenanthrene is selected as a representative pollution of PAHs in this experiment. The dynamic changes of soil enzyme activities were researche d under condition of phenanthrene exposure. The relationship between enzyme acti vities and different phenanthrene concentrations were investigated, and sensitiv e enzymes are considered as eco-toxicological indicators for soil diagnoses of PAHs contamination. The results showed that under condition of phenanthrene con centration > 100 ìg穔g-1, urease activity and dehydrogenase activity were inhibited within 3 days and 7 days respectively. However, the activity of phosph atase was activated by phenanthrene. There is no significant change of catalase activity in the phenanthrene with range of 100 to 2 400 ìg穔g-1 in the per iod of 28 day. It wa concluded that soil urease activity, dehydrogenase acitivit y, and phosphatase activity may be considered as diagnoses indicators of soil co ntamination with phenanthrene, and the most sensitive period of the diagnoses wa s from the first day to the seventh day after phenanthrene exposure.