Laserfiche WebLink
Metadata
Document management portal powered by Laserfiche WebLink 9 © 1998-2015 Laserfiche. All rights reserved.
14 April 1992 <br /> (GeoAudit CV 43A4-1.49) <br /> Page 3 of 3 <br /> LABORATORY ANALYSIS <br /> A total of eleven samples were analyzed: One from each of the hand <br /> auger borings and two from each of the regular borings. All samples <br /> were analyzed for Total Petroleum Hydrocarbons (TPH-gasoline) and <br /> BTE&X (benzene, toluene, ethylbenzene and xylene) in accordance <br /> with EPA methods 8015m and 8020. No contamination was detected in <br /> any of the samples (see attached laboratory analysis) . <br /> CONCLUSIONS <br /> 1. No contamination was encountered in the area of the former UST <br /> or the dispenser islands during the site assessment. <br /> 2 . Contamination was detected in a sample from a single soil <br /> boring drilled by BSK & Associates in February 1989 . The <br /> hydrocarbon contamination was encountered in a sample <br /> collected at 5. 5 feet. The shallow depth and low concentration <br /> (4 ppm) suggests that the contamination was not a result of a <br /> leaking UST. More likely, the contamination occurred as a <br /> result of overfilling or isolated discharge. <br /> 3 . Currently groundwater in the area is estimated at about 45 - <br /> 50 feet below surface grade. Seasonal high groundwater in the <br /> area (San Joaquin Flood Control Map "Depth to Groundwater in <br /> Wells -- Spring 198611) suggests a groundwater depth of about 30 <br /> feet below surface grade. It is not likely that groundwater <br /> was impacted from the minor contamination encountered in 1989. <br /> RECOMMENDATIONS <br /> Based on the results of 1) previous investigations, 2) the recent <br /> soil boring site assessment and 3) the laboratory analysis, no <br /> significant contamination is present on the property as a result of <br /> the past operation of UST's. The very minor contamination that was <br /> detected in 1989 was apparently an isolated occurrence. Considering <br /> that this sample was collected over three years ago from a very <br /> shallow depth we believe it poses no threat to groundwater. <br /> We recommend that authorization for site closure be granted by the <br /> San Joaquin County Public Health Services - Environmental Health <br /> Department. <br />