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area of the plume accounting for 5%more mass remaining. The pre-remediation estimated mass remaining from data sampled on 9/17/07 was I,IOOKg TPHg. The pump and treat system ran from 10/11/07 to 2/7/09 and is confirmed to have removed 1,025Kg TPHg. From the data of 3/9/10 combined with 7/19/10 the post remediation estimated mass remaining is 775Kg. 2). Mass Extraction Rate On 3/9/10 the concentration of TPHg at EW-1 was measured to be I 10,000ug/L. The well can make 15gpm at start up and sustain 12gpm in the spring and I 0gpm in the fall. 110,000ug/LG& lgpm=0.5996kg/day= 1.32191b/day I l0,000ug/L�l0gprn= 5.996kg/day= 13.219lb/day I I 0,000ug/L(a) ,12gpm=7.195kg/day= 15.862lb/day 3). Mass Susceptibility There is only V foot of fall along the length of the plume. EW-1 is capable of maintaining a 22' deep cone of depression which will reverse the flow of the groundwater. The whole plume remains susceptible to extraction. As the sampling data unveils with time, it would be prudent to consider moving the extraction well to keep it in the eye of the plume. The discharge pen-nit is only good for 15gpm. The advantage of groundwater extraction from the source is that the water will return the same path of least resistance automatically targeting the main column of the plume and bring in fresh water with oxygen along the leading edge of the plume for bacteria] degradation. Another advantage of groundwater extraction is that the remaining difficult areas are proven not susceptible to pumps in the distance. 4).Distribution of Contamination Water flows down gradient through the path of least resistance. The path of least resistance is through the sand layers. The sand layers are typically linear in nature like a river bed or beach that has been buried by silts and clays in times of flood. The silts and clays may distribute contamination by dissolution, but generally is not mobile. The sand layers will have the highest concentration and the most mobile contamination. On this site the 20-40' sand layer has 6% of the contamination, the 45-80' sand layer has 93.5% of the contamination, and the clays and silts below 80' have 0.5% of the contamination. In the N/E down gradient direction the plume is 360' long. The plume is about 160' wide. As mentioned above the mass of the plume is in the 45-80' sand layer. The plume in each water hearing layer has a definite eye horizontally centered on EW-1. EW-I is only screened on 45-60' below ground surface. EW-1 is screened and positioned to attack the highest concentrations without dragging them deeper or further down gradient. The EW-I screen will not allow the plumes to become worse.