1,4-二氯苯在褐土中的残留量变化及对几种土壤酶活性的影响

1,4-二氯苯(1,4-DCB)作为农药和化工产品生产的原料和中间体,在环境中的含量越来越多.采用气相色谱法对不同浓度1,4-DCB处理后土壤中药物残留量进行了测定;对1,4-DCB处理后褐土土壤中几种重要的氧化还原酶(多酚氧化酶、过氧化氢酶、脱氢酶)和脲酶活性进行测定,用其改变来反应1,4-DCB残留对土壤生态系统的影响.结果发现:在1,4-DCB处理30 d后,土壤中1,4-DCB残留保持在44%~50%;1,4-DCB处理后土壤中多酚氧化酶活性呈现先升高后降低的现象,酶活性峰值因作用时间和作用浓度不同而不同.与多酚氧化酶活性改变趋势不同,1,4-DCB处理后土壤脱氢酶活性降低.两种酶活性与1,4-DCB处理浓度之间均具有一定的浓度-效应和时间-效应关系.与多酚氧化酶和脱氢酶活性变化结果不同,1,4-DCB处理后土壤脲酶和过氧化氢酶的活性则随着处理浓度升高和处理时间延长而升高.因此,土壤中不同酶活性对1,4-DCB污染产生了不同的响应.

Change in 1,4-dichlorobenzene Residue and Its Effects on Soil Enzyme Activities in Cinnamon Soil

1,4-dichlorobenzene(1,4-DCB) is an important raw material and intermediate of most pesticides and chemical products.Its wide application resulted in its residual content gradually increasing in the environment.In this study,the residual content of 1,4-DCB and several key redox enzyme(polyphenol oxidase,catalase,dehydrogenase) activities in the soils were determined.The results showed that the residue rate of 1,4-DCB were 44%~50% in the soil treated by 1,4-DCB for 30 days.The activity of polyphenol oxidase was initially rose and then fell,and the peak values of its activity changed with the treated time and concentrations of 1,4-DCB.Unlike polyphenol oxidase,the activity of dehydrogenase was decreased with the increasing of 1,4-DCB concentrations.The activities of the two enzymes changed with the concentrations of 1,4-DCB in treated time-response and dose-response manners.Different from both polyphenol oxidase and dehydrogenase,the soil urease and catalase activities were increased with the enhanced concentrations and the prolonged time of 1,4-DCB treatment.This study suggested that different soil enzymes showed different response to 1,4-DCB treatment.