Hydrocarbon induced changes of magnetic properties in soil

人们普遍认为，磁性替代测量可以作为一种快速有效的工具来筛选土壤和沉积物中的人为重金属积累。也有一些迹象表明，碳氢化合物进入土壤会导致土壤磁性的改变。在这项建议中，我们希望研究土壤的磁性与德国北部前油田Wietze存在的有机化合物之间的关系。石油正渗透到那里的土壤中，自400年前以来，人们就在地表的油坑中开采这些资源。碳氢化合物浓度在几个地方仍然很严重，并明显主导其他影响，因此提供了一个理想的试验点，以确定输入有机化合物对土壤磁性的作用。本研究将包括关于石油浓度和化学、开采历史、土壤特性以及非常重要的地质微生物过程的磁性的量化，这些过程涉及微生物催化的铁矿物的氧化还原转化，从而导致土壤磁性矿物学的变化。结果将与使用磁性替代物(1)定性或半定量地描述土壤的有机污染和(2)有助于开发油气勘探/开采的辅助工具有关。

It is widely accepted that magnetic proxy measurements can serve as a fast and efficient tool for screening anthropogenic heavy metal accumulation in soils and sediments. There is also some indication that the input of hydrocarbons into soils lead to a change of soil magnetic properties. Within this proposal we want to study the relationship between magnetic properties of soil and the presence organic compounds at the former oil field Wietze in northern Germany. Oil was penetrating there into soil and people exploited these resources in surficial oil pits already since -400 years. Hydrocarbon concentration is still severe at several places and clearly dominates other effects, therefore providing an ideal test site to identify the role of input of organic compounds on the soil magnetic properties. The present study will include quantification of magnetic properties in respect to oil concentration and chemistry, history of exploitation, soil characteristics and, very important, geomicrobiological processes involving microbially catalyzed redox transformation of iron minerals that lead to changes in the magnetic mineralogy of soil. Results will be relevant for both using magnetic proxies (1) to qualitatively or semiquantitatively delineate organic contamination of soil and (2) to contribute to the development of a supplementary tool for hydrocarbon exploration/exploitation.