外源硒(Se^(4+)和Se^(6+))污染对土壤酶活性的影响  

Effects of Selenate and Selenite Pollution on Soil Enzymes Activity

作　　者：吴雄平[1] 武体侠[1] 付冬冬[1] 段曼莉[1] 魏威[1] 梁东丽[1] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100

出　　处：《农业环境科学学报》2010年第8期1526-1533,共8页Journal of Agro-Environment Science

基　　金：国家支撑计划项目(2008BADA4B09)

摘　　要：利用盆栽试验,研究了不同浓度、不同价态外源硒(Se4+、Se6+)对连续种植小白菜土壤中过氧化氢酶、脱氢酶、脲酶和碱性磷酸酶活性的影响,为土壤硒污染的生态风险评价和管理提供科学依据。结果表明:低浓度硒对土壤酶活性有不同程度的激活效应,而高浓度硒对4种土壤酶均产生抑制作用;外源硒对脲酶及脱氢酶活性的抑制作用大于碱性磷酸酶和过氧化氢酶。外源Se4+及Se6+浓度与土壤脲酶活性间都存在显著的负相关(P<0.01),且同浓度两个价态硒差异显著(P<0.05),说明脲酶可作为土壤硒污染程度的生态风险评价的生物指标;而过氧化氢酶、脱氢酶及碱性磷酸酶只能表征一定时间段内土壤硒污染的程度。土壤酶的ED5(0生态剂量)均随硒施入时间的延长而增大,以脲酶的ED50值最小,Se6+的ED50小于Se4+,生态毒性大于Se4+。The eco-toxicology effects of selenate and selenite pollution on catalase,dehydrogenase,urease and alkaline phosphatase in red-oil soil were studied through pot culture experiments under continually planting celery pakcho（iBrassica pekinensis）.The results showed that both low concentration selenium added as selenate and selenite had stimulate effects on all tested soil enzyme activitiy,while the highest con-centration of those two selenium forms had the biggest inhibition effects on soil enzymes activity.Selenate and selenite pollution had stronger inhibitory action on urease and dehydrogenase activity than on alkaline phosphatase and catalase activity.There was a significant negative correlation between inhibition rate of urease and selenium concentrations added as selenate or selenite,so it was feasible to use inhibition rate of urease as a biomarker of selenium ecological risk assessment.On the contrast,soil catalase,dehydrogenase and alkaline phosphatase activ-ity only could indicate pollution extent during some period time after pollution.Selenium concentration that induced enzyme activity declined to 50%（Eco-toxicology dose,ED50）raised with increasing application time,eco-toxicology effects of selenate and selenite continually de-creased with application time increasing.Among four tested enzymes,urease was the most sensitive one to selenium pollution and had the smallest ED50 value.Selenate had bigger eco-toxicology effects than selenite.

关 键 词：硒污染 硒酸盐(Se6+) 亚硒酸盐(Se4+) 土壤酶活性 抑制率 ED50 

分 类 号：X53[环境科学与工程—环境工程]