Laserfiche WebLink
1 <br /> GeolagualteclrxusInc Page 6 <br /> 4`h Quarter 2001 Groundwater Monitonng Report <br /> Project No 507 2 <br />�16 January 17,2002 <br />'1 <br /> • The groundwater gradient is relatively flat and the direction of groundwater flow has <br /> ' varied during the course of the investigation The site is quite close to the San Joaquin <br /> River and tidal fluctuations might be responsible for the observed changes in <br /> groundwater direction <br /> • Oxidation-Reduction Potential (ORP) was measured (Table 4) and the results suggests <br /> that nine of the ten wells sampled are either in the core of the contamination plume or <br /> are immediately down gradient of the plume and are within the halo of reaction depleted <br /> water caused by biodegradation of the contaminants <br /> The lateral extent of the contamination plume is defined to the east, northeast and southeast <br /> by wells MW-3, MW-2 and MW-1, respectively The plume is defined to the northwest and <br /> southwest by wells MW-10 and MW-7, respectively Figure 8 is a contour map indicating <br />' the wells' TPH-G concentrations on December 4, 2001 The vertical extent of the plume <br /> may be defined by MW-109 with additional monitoring, if the concentrations continue to <br /> decrease The groundwater plume is not defined to the north, between MW-2 and MW-10 <br /> The completion of the next quarterly event will conclude four consecutive quarters of <br /> groundwater monitoring since three new wells were installed in May 2001 GTI will make <br /> recommendations for a risk evaluation for the purposes of achieving site closure when the <br /> 1" Quarter 2002 event has been completed <br /> 3.0 LINIITATIONS <br />' This report was prepared in accordance with the accepted standards and practices of the <br /> field of environmental geology, groundwater hydrology and good business practices It <br /> should be recognized that definition and evaluation of environmental conditions is a <br /> Idifficult and an inexact science Judgments leading to conclusions and recommendations <br /> are generally made with an incomplete knowledge of the site-specific conditions present <br /> The tasks proposed and completed during this project were reviewed and approved by the <br /> local regulatory agency for compliance with the law No warranty, expressed or implied, is <br />' made <br />