ARCHIVED REPORTS XR0001661 - Laserfiche WebLink

Home Browse Search

3 I 20 April 1998 AGE-NC Project No 95-0109 Page 3 of 5 J 3'2 MICROBIOLOGICAL ACTIVITY IN GROUND WATER General rmcrobiological plate counts decreased slightly in the ground water sample collected from �-MW-9 and MW-14 during the first quarter of 1998,-wlule selective plate counts showed a slight - -' increase in MW-9 and MW-14 Nutrient concentrations increased slightly in MW-9 and MW-14 Absolute numbers of both plate counts and nutrients remain below optimum levels Total nitrogen Concentrations of 100 parts per million (ppm) are optimum for maximum biodegradation,and concentrations of 10 to 30 ppm are adequate for to maintain biodegradation The concentrations detected in the two samples analyzed, <0 1 to 8 1 ppm, Indicate that site conditions are less than adequate to promote significant biologic breakdown of the hydrocarbon contaminants Chemical and microbiological data for ground water are summarized on Table 2 and Table 3 The, laboratory report (A Keith Kaufman - 25 March 1998) and chain-of-custody form are included in Appendix B i _ e I , 4 A 3 3 - PETROLEUM HYDROCARBON-IMPACTED GROUND WATER Y During the March 1998 sampling event, petroleum hydrocarbons were detected in ground water samples from nine of the fifteen wells sampled TPH-g concentrations ranged from below laboratory method detection limits to 1,400 parts per billion (ppb, reported as micrograms per liter) BTE&X were detected at concentrations as high as 72 ppb benzene, 130 ppb toluene, 26 ppb ethylbenzene, and 320 ppb xylenes The highest concentrations of each constituent were detected in MW-14 TPH- g and BTE&X were not detected in samples collected from MW-2, MW-3, MW-6, MW-9, MW-12 I: or MW-13 during the March 1998 sampling is Tertiary butanol was detected In MW4 and MW-5 at concentrations of 80 ppb and 33 ppb, I respectively Other,oxygenated compodhds were not detected in the samples collected during the March 1998 sampling event 1,2-Dichloroethane (1,2-DCA)was detected,in MW-4,,MW-5, MW-8, �f MW-1I and MW-14 at concentrations ranging from 2 5 ppb to'500 ppb 1,1'-Dichloroethane was detected in MW-1 at a concentration of 14 ppb Other analytes tested were not detected However, due to the necessity of using a different laboratory fortheEPA Method 8260 analysis, several t, analytes previously detected at the site were not included on the laboratory report I , 1,2-DCA was detected by EPA Method 601 in the samples collected from MW-8 and MW-14 at concentrations of 2 1 ppb and 3 9 ppb, respectively 1',2-DCA was not detected In samples collected from MW-7, MW-9, MW-21, MW-13 or EW=1'by EPA Method 601 Analytical results of ground water samples are summarized on Tables 4 through 6 The laboratory �f report(MAI Laboratory I D Nos 8b658 through 86672) and chain-of-custody forms are Included Advanced GeoEnvironmental,'Ine r I I r '