石油污染地下水有机污染组分特征及其环境指示效应

通过采集我国北方某污染场地地下水样品,用GC-MS扫描分析石油烃成分及含量,研究油田开采情况下石油烃污染物在地下水中的分布变化及其对环境的指示作用.结果表明,地下水中总石油烃(TPH)均值为4.75mg/L;组分包括烷烃、芳香烃、酯类、醛类以及醇类等有机化合物,烷烃类含量最高,占总油百分含量平均值为65.6%;沿着地下水流向烷烃和芳香烃所占百分含量减少,分别从70.05%和14.56%下降至57.72%和10.58%,而非烃类逐渐富集,其百分含量从15.39%增加至31.72%.由样品色谱参数可知:场地Pr/Ph值在0.73~1.27之间,表明地下水处于缺氧的还原环境;Pr/C17值在0.42~1.51之间;Ph/C18值在0.61~1.30之间,指示出较强的微生物作用;细菌数与非烃类含量、Pr/C17以及Ph/C18之间呈现出正线性相关性,Pr/C17和Ph/C18值越大微生物作用越强.不同季节对石油烃浓度变化也有一定影响.

Organic fractious and their environmental implications of petroleum contaminated groundwater

The hydrogeochemitry at a petroleum contaminated site was systematically studied to understand the fractional compositions and their environmental indications of oil contamination in groundwater. The GC-MS scanning for saturated hydrocarbon fractions and the corresponding biomarkers of the groundwater samples were determined at various spatial and temporal scales. The average TPH was 4.75mg/L. Alkanes(65.6% of TPH), aromatic, esters, aldehydes, alcohols were all detected in groundwater changing along with groundwater flow. There was a reduction of Alkanes from 70.05% to 57.72%, Aromatic from 14.56% to 10.58% and an enrichment of the microbial degradation products from 15.39% to 31.72%. An anaerobic reductive environment was indicated by the low value of Pr/Ph, ranging between 0.73 and 1.27. The ratios of Pr/C17 (ranging between 0.42 and 1.51) and Ph/C18 (ranging between 0.61 and 1.30) indicated extensive biodegradation. The total bacteria number was positively correlated to non-alkanes, Pr/C17 and Ph/C18 ratios; higher ratios demonstrated a more extensive biodegradation. The organic fractions were also influenced by seasons in temperature variation.