Is it possible to remove the ...

Is it possible to remove the contaminated oil from ground water used for agriculture and drinking ?

The answer to your question is found in a technology called BioRemediation. The "Father" of this technology was  Dr Carl H. Oppenheimer jr. The microbial species he discovered and worked with for more than 40 years was called ARCHAEA. Their singular function in nature is to reduce organic compounds into their elemental form.  Once they are in contact with the oil. (or any toxic substance) they will biodegrade it until it reaches elemental form. In this case carbon. The by products are usually oxygen and any other impurities in that grade of oil. Results are a potable drinking water, nutrients normally found in nature which will be consumed by all life in the soil and of course highly oxygenated water usable by all. 

 First open water test was in 1990, Houston channel by University of Texas and The Texas land commission  many international uses since then. Most notably the Spain oil spill, the Galapagos island, the north sea of japan. a total of 2500 clean ups around the world.   For info and reports/pictures and videos email biozomesales@biozome.com.  Guy