WORK PLANS - Laserfiche WebLink

Home Browse Search

Site investigation Work Plan-Second Revision Raymond Investment Corporation Former Helena Chemical Facility Page 7 concentration would be invalidated or assigned a value of non-detect.The five soil field duplicates will be collected within one foot of each corresponding counterpart. If the soil field duplicate laboratory analytical result is within 60 percent of the result of its primary counterpart, then other primary analytical results should be considered representative of the soil between sampling intervals. If the soil duplicate analytical results do not agree with their primary counterpart, then the distribution of some analytes may be considered heterogeneous. If the distribution of some analytes appears to be heterogeneous,then future sampling may need to be done at other depths or with smaller sampling intervals. The same principals may be applied to the groundwater duplicate sample. The proceeding data quality indicators should be sufficient to validate the precision, accuracy, and sensitivity of the data collected. An estimated non-detection boundary will be made. This will be supported by a graph of concentration versus distance from source that will be made for nitrates to estimate where the boundary may lie to the north where sampling is not planned. These secondary indicators will be used to evaluate representativeness, completeness of the investigation. Data collected from this investigation will be compared to data from previous investigations to evaluate the comparability of that data in terms of varied sampling and analytical methods and temporal trends. The data, data management, and analysis will be reviewed with a Tier 2 validation during the Condor review process. 4.0 SITE PREPARATION Condor's proposed soil and groundwater investigation will include additional soil and groundwater sampling, then the installation, development, and survey of three groundwater monitoring wells at the Site. The work to be completed by Condor will consist of the following tasks: Condor will obtain an encroachment permit from the City of Stockton to drill and sample at four (4) locations within the northbound lanes of Tillie Lewis Drive. Drilling in the traffic lanes of Tillie Lewis Drive is necessary because utilities are located in the adjacent shoulder of the road. Condor will obtain a soil boring permit from SJCEHD prior to scheduling field activities with the sub-contractors and notifying Underground Services Alert. Condor will obtain a monitoring well installation permit from SJCEHD prior to scheduling field activities with the sub-contractors. Different drilling sub-contractors and permits may be used for the soil borings and well installations to utilize specialized equipment for each task. Prior to initiating fieldwork at the Site, all field personnel will familiarize themselves with the Site-Specific Health and Safety Plan(HASP, Appendix B). In addition, a tailgate safety meeting will be held prior to commencement of fieldwork. The HASP pertains to field activities and includes information on potential hazards expected to be encountered at the Site, personal protective equipment, and directions to and telephone numbers for the nearest hospital.A copy of the HASP is included in Appendix B. 5.0 SOIL AND GROUNDWATER SAMPLING FIELDWORK Condor will obtain the services of an underground utility locating sub-contractor to supplement the locations provided by public utilities during the USA process. The lessees or the client will accept the boring locations and confirm the location of underground utilities. Condor proposes drilling and collecting soil samples from fourteen (14) locations and groundwater samples from eight (8) locations, and the installation of three(3)monitoring wells,completed as a second phase after the results of the first phase of drilling and sampling have been evaluated. Soil samples will be collected for the purpose of characterizing the lithology of the subsurface soils and for laboratory analysis to define the lateral and vertical extent of soil impacted by nitrates. Soil samples will be collected using Geoprobe or similar direct push equipment that has been successful at this Site in the past. A dual tube system will be used for soil samples. A hydropunch system will be used for groundwater samples. Groundwater samples will be collected from eight borings at eleven to fifteen feet below the surface, or where practical based on field conditions.Depth to water and permeability vary significantly,as indicated by the 2013 Phase II sampling n ILA CONDO