Laserfiche WebLink
E i Tri-Valley Growers <br /> March 24, 1988 <br /> Project No. 1582G Page 7 <br /> 3) Analytical results from the soil samples from exploratory boring MW-4 <br /> show that concentrations of TEH, TVH and BTX are BDL of the laboratory. The <br /> I i concentration of total lead (5.6 ppm) is below the DHS Hazardous Waste <br /> Threshold Limit concentrations for total lead in soil. In our opinion, the lead <br /> k concentration present in MW-4 ground-water is at background levels. <br /> 4) Concentrations of benzene and toluene in the water sample from MW-4 are <br /> above the DHS action levels for these chemicals in water. The San Joaquin <br /> I Local Health District may require Tri-Valley Growers to verify the <br /> i.� horizontal extent of ground-water contamination. This may entail the <br /> installation of one or more additional monitoring wells. <br /> 5) Due to the flat and changing ground-water surface at this site, in our <br /> E opinion, the four site monitoring wells should be measured for ground-water <br /> i <br /> surface changes on a monthly basis for six mbnths. Ground-water surface <br /> maps would be constructed to si-,ow any changes in the water table surface. <br /> At the end of the specified p period, additional monitoring wells (if required) <br /> ["t'A could be strategically located to bettc-: define the extent of ground-water <br /> I contamination. Within this six month piriod, Tri-Valley Growers would like <br /> t{ to ascertain the status of the adjacent property owner's old gasoline <br /> t facility and if it is contributing to the local ground-water contamination. <br /> Based on the data collected to date, lead in the ground-water beneath the <br /> site, in our opinion, is present at background concentrations. Further total <br /> lead analyses are therefore not warranted. Tri-Valley would like to <br /> ' ascertain the status of the adj gent subsurface tank on the adjoining <br /> property. <br /> 6) The adjacent domcol:'o well construction details need to be provided to Tri- <br /> Valley Growers for evaluation of its shallow ground-water monitoring use. <br /> If this well is completed in a deeper aquifer, it cannot be used to monitor <br /> the shallow. <br /> _ ground-vrater._at.-this_site. <br /> --- <br /> 7) Copies of this report should be forwarded to the San Joaquin Local Health <br /> District (SJLHD) and the California Regional Water Quality Control Board <br /> -- (RWQCB), Central Valley Region. <br />