为研究莫莫格湿地油田开采区土壤石油烃污染及对土壤的影响,分别在油田开采区不同开采年限的油井周围和自然湿地对照区采集土壤样品,测定了土壤总石油烃、总有机碳、总氮、总磷、pH值和电导率.结果表明,所有油田开采区油井周围土壤中总石油烃含量显著高于对照区(p〈0.05),开采5、10和20 a的油井周围土壤总石油烃含量分别是对照区土壤的30、60和111倍.土壤石油污染在莫莫格湿地油田开采区普通存在.开采10 a以上的中长期油井周围土壤是石油烃污染的主要区域,其平均含量在16 885-31 230 mg.kg-1之间.土壤总有机碳与总石油烃呈显著正相关(r=0.88,p〈0.05),土壤中残留的石油烃导致了土壤总氮和总磷下降,下降最大值分别为33%和28%.土壤石油烃污染显著增加了碳氮比、碳磷比和pH值(p〈0.05),这种趋势随着油井开采时间增加而增大.土壤石油污染也引起电导率的增加,但是影响并不显著(p〉0.05).土壤石油烃污染在很大程度上改变了土壤的性质,对土壤质量产生了负面影响.
Momoge Wetland is an important international wetland. Crude oil exploration and production have been the largest anthropogenic factor contributing to the degradation of Momoge Wetland, China. To study the effects of crude oil residuals on wetland soils, the total petroleum hydrocarbon (TPH), total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) were examined, as well as for pH and electricity conductivity (EC) from oilfield and uncontaminated area in Momoge Wetland. All contaminated areas had significantly higher (p〈0.05) contents of TPH than those of the uncontaminated areas. For 5 a, 10 a and 20 a oil weUs, the TPH were 30-fold, 60-fold, and ill-fold of the control sites. Soils from 10 a or over 10 a oil wells in oil-field were the major petroleum contamination area with values ranging from 16 885 mg·kg^-1 to 31 230 mg·kg^-1 . There was a significantly positive correlation between TOC and TPH contents in oilfield( r = 0.88, p 〈0.05). Oil residuals in soil caused the decrease of TN and TP and the maximum of decline were 33% and 28%, respectively. Contaminated sites also exhibited significantly higher ( p 〈 0.05 ) pH values, C : N and C : P ratios. These trends became progressively obvious with the length of time the oil well was in production. Soil petroleum contamination also resulted the increase of the EC, however the impact of TPH on EC were not significant(p 〉 0.05). Collectively, petroleum hydrocarbon pollution has caused some major changes in soil properties in Momoge Wetland.