ARCHIVED REPORTS XR0012675 - Laserfiche WebLink

Home Browse Search

�M.�. ,mer,• _ � "�s�'�. i"r�'' ",.- �'�y�, 'P r�,�„�^•^[_w °°: _ � �'� "�' �' �^.�, a �•^c��'�'� Site Geology andjjvdroloav Soils encountered while drilling were relatively continuous, consisting of silty clays, loams and fine silty sands. The soil units are lensoidal and not laterally extensive or continuous. Permeabilities are low and range from 1.6 x 10-7 to 2.0 X 10-5. Groundwater beneath the site is at a depth of approxivately 62 feet and the gradient is to the north east at 'a rate .of 0.0075 ft/ft. It should be noted that the groundwater level has dropped about 25 feet since mid 1987. Plate 4 shows area groundwater depths in Spring 1989 as provided by Flood Control District. There is one producing well within 1/2 mile of the site. There are several large seasonally used wells east and north of the site at canneries. All wells within 1-1/2 mile are shown on Plate 3. r 4, Finds - Regults of Chemical Analysis The three bore holes,' Mw 9, 10 & 11, are the data sources used .in determining the vertical and horizontal eutent of soil and'ground- water contamination. A total of 24 undisturbed soil samples and 6 groundwater samples were analyzed for gasolina and its components, specifically, total petroleum hydrocarbons (TPH Gasoline) as. well as aromatic volatile organics by Benzene, Toluene, Ethy.l.• Benzene and total Xylenes (BTX & E) . Laboratory Yxdata sheets for each are presented in the Appendix and results are _ tabulated in Table 4 & 5. No soil samples above 30 were analyzed. _ The Kleinf elder Report indicated soil hydrocarbons would not extend to MW 9, 10 & 11 due to location. Soil analyses reveal virtually no contamination in any bore hole/monitor well sample areas. The, low. levels. of TPH in Mw 91 10 & 11 are weld below any .required action level-. The same is true for Toluene and Xylene in MW 9, 10 & 11. Water analyses reveal virtually no contamination. Benzene in MINT s. 11 at 1.0 part per billion on 3/30/90 is the only analysis near an action level. It is also noted that the same well tested Benzene as non-detectable on 4/24/90. Conclusions The results of the Phase II Investigation confirm that there is no soil or groundwater contamination in bore holes/monitor wells 9, l0__.&__11_at_a..._1evel_to_require_any___remedial_action ._.__.____. Page 6