[Petroleum hydrocarbon contamination and impact on soil characteristics from oilfield Momoge Wetland].

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 wells, the TPH were 30-fold, 60-fold, and 111-fold of the control sites. Soils from 10 a or over 10 a oil wells in oilfield were the major petroleum contamination area with values ranging from 16,885 mg x kg(-1) to 31,230 mg x 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.