定靖油气田区地下水有机污染特征初步分析

Preliminary analysis on the organic contamination in groundwater of Dingjing oil-gas field region

以地下水水质检测数据为基础,从污染源分布及水文地质条件入手,对定靖油气田区地下水有机污染分布特征及其成因进行了研究,本文检测了卤代烃15项、氯代苯5项、单环芳烃5项、有机氯农药11项和多环芳烃1项,结果发现该地区地下水有机污染具有检出种类少,检出率高,浓度低,超标率低的特点.地下水中检出的有机污染物共有10种,分别为甲苯、苯、邻二甲苯、苯乙烯、二氯甲烷、1,2-二氯乙烷、1,2-二氯丙烷、1,2-二氯苯、1,2,4-三氯苯和苯并(a)芘,检出的9项有机污染物含量均低于《地下水质量标准》(GB/T14848—2007)三类水限值.潜水的检出项比承压水的检出项多,检出率普遍比承压水的检出率高.不同地貌类型的有机污染物检出率为黄土区(28.87%)≈平原区(27.76%)>沙漠滩地区(11.11%)>河谷区(3.33%).最后,从工业污染源、有机物理化性质和水文地质条件对有机污染分布特征的成因进行了阐述.

Based on groundwater quality test data,from the aspect of pollution distribution and hydrogeolo-gyical condition, distribution characteristics and source of organic contamination in groundwater of Dingjing oil-gas field region have been studied. This work analyzed fifteen halogenated hydrocarbons,five chlorobenzene,five monocyclic aromatic hydrocarbons,eleven organochlorine pesticides and one polycyclic aromatic hydrocarbon. The results showed that the characteristics of organic contamination in groundwater in this area were low numbers of contaminants,high detection rate,low concentration,low over standard rate. There were 10 organic contaminants detected in groundwater, i. e., toluene, benzene, ortho-xylene, styrene,dichloromethane,1,2-dichloroethane,1,2-dichloropropane,1,2-dichlorobenzene,1,2,4-trichlorobenzene and benzo（ a） pyrene. Content of the nine compounds did not exceed Ⅲ-water limit of＂quality standard for groundwater＂（ GB / T14848—2007）. The number of detected pollutiants in the phreatic water was high than the confined water,and the detection rate was also higher than the confinedwater. The detection rate of the groundwater organic pollutants in the different topographic avers was in the order of the loess area（ 28.87%） ≈the plains（ 27.76%） the desert pool area（ 11.11%） the river valley area（ 3. 33%）. The effect on the temporal and spatial distribution by some factors,including industrial pollution sources,physical and chemical properties of organic contaminants and hydrogeological conditions were discussed.