舟山海洋沉积物及沿海沉积物流动相石油污染的电阻率特性及其影响因素研究

摘要

海洋沉积物作为难以降解的石油类污染物的最终归宿,其污染程度的监测至关重要.本文通过现场采集舟山海洋沉积物及沿海沉积物(包括中砂、粉砂质砂和粉砂),以流动相原油为代表,采用单因素分析法室内配制标准污染沉积物样品测定电阻率,探讨沉积物类型、含水率、含油率、时间因素对石油污染海洋及沿海沉积物的电阻率影响及变化规律.结果显示,未污染和原油污染后海洋沉积物中砂、粉砂质砂、粉砂的电阻率随含水率的升高均呈幂函数降低趋势,并符合Archie公式.在含水率15％时,电阻率随含油率总体上升;而在含水率5％时,中砂电阻率呈现一个小幅上升的趋势;粉砂电阻率先小幅下降后略上升再小幅下降,粉砂质砂电阻率则是先大幅下降后略上升再小幅下降.15％含水率污染沉积物的电阻率随时间增加持续上升;5％含水率污染沉积物电阻率先上升后略下降再大幅上升.研究成果可为海洋及沿海沉积物石油污染电阻率法快速监测提供理论支持,以期为海洋环境管理部门提供相应的决策依据.%Marine sediments is considered as the final destination of the petroleum pollutants degraded difficultly,and the monitoring of pollution degree is very important.Through collecting in-situ marine and coastal sediment samples in Zhoushan (including medium sand,silty sand and silt),and selecting mobile phase crude oil as typical representative,the resistivities of standard crude oil contaminated sediment samples which were prepared indoor were measured using single factor analysis method,and then effect of sediment types,water content,oil content and time on the oil contaminated sediment resistivites and the according changing rules were discussed.Results showed that the resistivities of clean and oil-contaminated medium sand,silty sand and silt all decreased in the form of power function with the increasing water content and conformed to the Archie formula.When the water content was 15％,the resistivity rose with the increase of oil content overall.While the water content was 5％,the change rules of resistivity of three kinds of sediment were different.The resistivity of medium sand presented a small increasing trend,and the resistivity of silt decreased slightly firstly,rose a little afterly,and then decreased slightly again.The resistivity of silty sand decreased largely firstly,rose slightly afterly and decreased slightly.The contaminated sediment resistivities with 15％ water content kept rising,while with 5％ water content the resistivities rose firstly,decreased slightly,and then rose largely.Research results can provide theoretical support to the fast monitoring of oil contamination of marine and coastal sediments by the method of resistivity,and then provide the decision-making basis for the marine environment management department.