Laserfiche WebLink
[n <br /> r N. <br /> c <br /> CLEARWATEK <br /> C R O [1 P <br /> Before sampling, the wells were piftednwrM41 Wftt6gesquality parameters had stabilized. <br /> Stabilization occurred after approximately three wet casing volumes had been removed. Prior to <br /> purging, the wells were checked for the presence of light non-aqueous-phase liquids (LNAPL), <br /> which were not detected in the wells. Stabilization measurements of purged groundwater <br /> E.1�: <br /> r�_:- <br /> ,A4e; <br /> temperature, conductivity, and pH were made and recorded for each well prior to sample <br /> collection. <br /> Following purging, each well was allowed to recharge to at least 80% of its static water level <br /> prior to sampling. Groundwater samples were obtained from each well using disposable <br /> polyethylene bailers and decanted into clean laboratory supplied bottles. Samples were labeled, <br /> documented on a chain-of-custody form, and placed on ice in a cooler for transport to the project <br /> laboratory. Groundwater samples were analyzed by Kiff Analytical Labs, located in Davis <br /> California, a California State-certified laboratory, for concentrations of TPHg, BTEX and MTBE <br /> by EPA Method 8260B. All field work was conducted in accordance with Clearwater's <br /> Groundwater Monitoring and Sampling Field Procedures and Natural Attenuation Processes <br /> and Recommended Monitoring Guidelines. <br /> 3.1 Dissolved Oxygen, ORP, Total and Ferrous Iron Field Testing <br /> Following well purging, Clearwater monitored dissolved oxygen (DO), and oxidation-reduction <br /> potential (ORP) using pre-cleaned down-well probes, and collected water samples for in-the- <br /> field iron testing (total iron, and ferrous iron) using portable iron test kits. Dissolved oxygen <br /> concentrations ranged from 0.1 mg/L in MW-2 to 1.5 mg/L in MW-8. Oxidation-reduction <br /> potential ranged from. —8 millivolts in MW-8 to 20 millivolts in MW-3. Total iron <br /> concentrations ranged from 0.0 mg/L to 1.3 mg/L in MW-4 and MW-7. Ferrous iron (Fe+2) is <br /> in the "reduced" state, and ranged from 0.0 mg/L in MW-2 to 1.1 mg/L in MW-5B. Refer to <br /> Table 4 for the DO, ORP, Total iron, and ferrous iron data. <br /> ZBII�Fl.iSC b �+ytngF &tiolgl�. 04 <br /> ew sCSu venuenstall �tl� rnond,California 901 ® Telephone: 510-307-9943 ® Fax: S1UNI22�g <br />