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• • • SECTION 4.0 ACTIVITIES COMPLETED DURING THE REPORTING PERIOD • • 4.2 Annual Tree Survey • The annual tree survey was completed on August 9,2011.Observations made during the annual tree survey are presented and discussed in Section 6 and photographs taken during the tree survey are presented in Appendix E. • • 4.3 Ten-year Evaluation Soil Sampling • Soil sampling was performed at the existing phytoremediation groves on July 12 and July • 13,2011,in accordance with the RAP(CH2M HILL,2000b)and the Ten-year Sampling Event • and Additional Investigation at Former Bagging Plant Work Plan (Work Plan) (CH2M HILL, 2011).Soil samples were collected from a circular area with a diameter of approximately • 35 feet from each of the five planting locations(original test grove,turnaround area,north of • the warehouse,former bagging plant, and stormwater pond).Within each circular area, • borings were advanced using a hand auger at eight locations to a total depth of 6 feet bgs. Soil samples from each boring were divided into three depth intervals: 0 to 2,2 to 4,and 4 to • 6 feet bgs.The eight samples,excluding duplicate samples,from each depth interval were • composited and submitted for analysis.Soil samples were analyzed for TKN,nitrate as nitrogen(nitrate-N),soluble ammonia/ammonium as nitrogen(via saturation paste extract), • and pH;a few samples were also analyzed for exchangeable ammonia/ammonium as • nitrogen (via KCI extraction).The relative concentrations of soluble ammonia-nitrogen and • soluble ammonium-nitrogen(ammonia/ammonium-N) were then calculated by the laboratory on the basis of the concentration of measured total soluble • ammonia/ammonium-N,pKa,and measured pH.The results of exchangeable ammonia/ • ammonium analysis generally represent the concentration of ammonium due to the pH • (near neutral to slightly acidic) of the extract and will be referred to as exchangeable ammonium throughout the text for simplicityl. • The soil sample locations were consistent with the locations of soil samples collected in 2006 • as part of the 5-year remedy evaluation.Figures 4-1 through 4-4 show the approximate • locations of the seven sample areas (1K through 7K). • Results of soil samples collected for the Ten-year Evaluation to evaluate the • phytoremediation remedy are presented in Section 5 and discussed in Section 6. • 4.4 Former Bagging Plant Soil and Groundwater Investigation • Eight soil borings were advanced in the former bagging plant on July 11,2011,in accordance with the Work Plan (CH2M HILL,2011).At each boring location,soil samples were collected from three depth intervals:0 to 2 feet bgs,2 to 4 feet bgs,and 4 to 6 feet bgs.The • 24 samples,excluding duplicate samples,were analyzed for TKN,nitrate-N,soluble • ammonia-N/ammonium-N (via saturation paste extract),pH, and exchangeable ammonium • 1 Exchangeable ammonium as reported in the text is actually extractable ammonium,which includes both • exchangeable ammonium and soluble ammonium. Because soluble ammonium levels were typically not • detected or were detected at low levels as compared to exchangeable ammonium,for simplicity,exchangeable ammonium and extractable ammonium are not differentiated in the text.The error in the assumption is somewhat • greater for area 3K where soluble ammonium levels are greater. • 4-2 RDD1112370001(CAH5003.DOCX) • rsa 11e Va D • • •