菲不同污染方式对土壤酶活性的影响

Effect of Phenanthrene Pollution with One-time and Cumulative Patterns on Soil Enzymatic Activity

菲作为多环芳烃类污染物的代表，正以低剂量叠加的方式在土壤中逐步累积，对土壤生态安全造成潜在威胁。本研究模拟菲在一次污染和累积污染方式下对土壤酶活性的影响及其与菲有效性之间的关系。结果表明，在菲累积和一次污染条件下，土壤菲可提取态和有效态含量随培养时间的延长呈现出前2周（1～14d）下降速率较快，3～8周（14～56d）逐渐减缓的趋势。与一次污染相比，累积污染的土壤菲可提取量和有效态含量均较低。在2种污染方式下，土壤脲酶，脱氢酶和蔗糖酶均存在不同程度的被抑制现象，并且酶活性在前2周被短时间抑制，3～8周酶活性被激活而增强。与一次污染相比，累积污染的土壤酶活性被抑制效应减弱。土壤脱氢酶对菲污染反应灵敏，并与土壤可提取态和有效态菲含量显著相关，最能反映菲在土壤中的环境风险。

Phenanthrene, a representative of polycyclic aromatic hydrocarbons （ PAHs）, is gradually accumulating with superposed manner at a low dose in the soil, and will cause a potential threat to soil ecological safety. The effects of accumulated phenanthrene on soil enzymatic activity and available phenanthrene compared with one-time pollution were investigated by using superimposed methods under the simulated condition in the lab. The results showed that, soil extractable and available contents of phenanthrene were quickly declined in the first 14 days, and then decreased slowly from 14 to 56 days under the one-time and accumulated pollution conditions. The soil extractable and available contents of phenanthrene were lower in accumulated pollution samples than in one-time pollution samples. Under these two pollution modes, soil urease, sucrase and dehydrogenase activities were inhibited in the early stage （14d） and stimulated at the rest of the incubation time. Compared with one-time pollution, soil enzyme activity was weakly inhibited in the accumulated pollution. Soil dehydrogenase activity was the most sensitive to phenanthrene pollution and significantly correlated with soil extractable and available phenanthrene, whieh could be the best indicator to reflect the environmental risk of phenanthrene in soil.