FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

Manteca Unified School District r Soil&Groundwater Investigation Repot Page: 3 r the introduction of contamination from off site, and between borings to prevent cross contamination. The borings were logged under the direct supervision of a registered geologist using the Unified Soil Classification System. The color, texture, moisture, plasticity (if applicable), consistency of the earth materials, pertinent soil or bedrock characteristics, and any evidence of contamination will be noted. All water-bearing zones and the depths at which they are encountered are noted on these logs. The borings were drilled in such a manner as to prevent cross contamination between strata. Water samples were taken at the soil/groundwater interface, and the borings were then terminated with a cement mixture. r 2.2 Soil Sampling All soil sampling equipment was thoroughly steam cleaned before and between sampling to prevent cross contamination. Relatively undisturbed soil samples were taken at intervals of not more than five feet (5') in order to evaluate the subsurface materials. The soil samples were obtained using a Geoprobe® core sampler with plastic liners. The sampler was pushed (Direct Push Technology) continuously by the hydraulically powered, percussion system. The laboratory samples did not have headspace and were immediately sealed in their liners using plastic caps. The remaining sample was removed from its liner to be used as an aide to the on-site geologist in logging the material at that depth. Y� All soil samples were delivered, under chain of custody, to an analytical laboratory licensed by the State of California for hazardous materials work. The samples were analyzed for Total Petroleum Hydrocarbons (Diesel) and BTEX. Analyses were conducted by GeoAnalytical Laboratories, Inc., in Modesto, California. V 2.3 Groundwater Sampling All sampling equipment, including the stainless steel Geoprobe® screen point, used by sampling personnel, was disassembled and steam cleaned prior to commencement of sampling. Water samples were collected through a Teflon tube with a ball check valve assembly. The groundwater sample was analyzed or extracted within 14 days according to their EPA methods. It was analyzed for Total Petroleum Hydrocarbons (Diesel) and BTEX(Benzene, Toluene, Xylene, and Ethyl Benzene). Analysis was conducted by GeoAnalytical Laboratories, Inc. in Modesto, California. V V