ARCHIVED REPORTS_REPORTS - Laserfiche WebLink

Home Browse Search

• • • • SECTION 5.0 RESULTS • • The concentrations of total soluble ammonia/ammonium-N in soil samples collected from . soil sampling area 3K in 2011 decreased in all depth intervals relative to 2006 results • (ranging from 458 to 1,640 mg/kg in 2006 to 11.9 to 69.4 mg/kg in 2011).The concentrations of total soluble ammonia/ammonium-N in soil samples collected from soil sampling area • 4K in 2011 were less than 0.5 mg/kg for all depth intervals.Exchangeable ammonium • concentrations in 2011 soil samples collected from soil sampling location 3K have stabilized at the 0 to 2 feet bgs soil sampling interval and increased in the 2 to 4 and 4 to 6 feet bgs • relative to baseline concentrations (2000),with concentrations ranging from 13 to 80 mg/kg • in 2000 and 89.3 to 475 mg/kg in 2011. Exchangeable ammonium concentrations in 2011 at • soil sampling area 4K decreased at all depth intervals relative to baseline (2000) concentrations,with concentrations ranging from 644 to 1,298 mg/kg in 2000 and 3.94 to 6.09 mg/kg in 2011. • TKN concentrations in soil samples collected from soil sampling areas 3K and 4K in 2011 • were generally less than baseline or stabilized compared to baseline(2000)concentrations. • The concentrations of TKN in 2011 soil samples from soil sampling areas 3K and 4K were generally less than or stabilized compared with concentrations in 2006 samples,except for • the 4 to 6 feet bgs interval of soil sampling area 4K,where concentrations increased from • 420 to 1,720 mg/kg. Concentrations of total nitrogen(TKN plus nitrate-N) in soil samples • collected in 2011 from soil sampling areas 3K and 4K remained greater than the 200-mg/kg cleanup goal,but are generally decreasing relative to previous results.Additional discussion • of soil sampling results at soil sampling area 3K and 4K relative to the 2011 investigation at • the former bagging plant area is presented in Section 5.2.2. • The soil samples collected from the former bagging plant area were generally more acidic than soil samples collected from other areas,with pH ranging from approximately 4 to 7. • The lowest pH was measured at the 3K soil sampling area in the samples collected from 2 to • 4 feet bgs(pH of 4.32) and 4 to 6 feet bgs (pH of 3.84).In general,the soil samples collected • from soil sampling area 4K have become more alkaline since the baseline sampling in 2000 and the soil samples in the 3K area have become more acidic since the baseline sampling on 2000. • Stormwater Pond • Soil sampling areas 1K and 7K in the stormwater pond area are shown on Figure 4-4.Nitrate • concentrations as nitrate at both locations 1K and 7K are below 1 mg/kg,except for the 4 to • 6 feet bgs sample from 7K,which increased from below the laboratory detection limit in • 2006 to 98.2 mg/kg in 2011.Total soluble ammonia/ammonium-N concentrations for all samples collected from soil sampling areas 1K and 7K collected in 2011 were below the • laboratory detection limits. • The concentration of TKN in soil continued to decrease in the 0 to 2 feet bgs sample from • soil sampling area 1K,but increased slightly in the 2 to 4 feet bgs sample,and stabilized in • the 4 to 6 feet bgs sample relative to the 2006 results.However,the 2 to 4 and 4 to 6 feet bgs samples from soil sampling area 1K still show an overall decrease in concentration relative • to the baseline concentrations (2000).Soil samples were not collected in 2000 at soil • sampling location 7K,but TKN concentrations in the 0 to 2 and 2 to 4 feet bgs samples were relatively stable and TKN concentrations in the 4 to 6 feet bgs samples decreased from • 2,700 mg/kg to 367 mg/kg from 2006 to 2011.The concentrations of total nitrogen(TKN • • RDD1112370001(CPH5003.DOCX) 5'11 esoazsnazmwoo • • •