acetone production as a result of sodium bisulfate preservation using epa method...
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Acetone Productionas a Result of Sodium Bisulfate Preservation
Using EPA Method 5035
Jay Clausen (Ogden)Elizabeth Wessling (Ogden)
Marilyn Hoyt (Ogden)Bryce Stearns (STL - Burlington)
Bosci Ramirez (STL - Chicago)
Presented at the 16th Annual Conference on Contaminated Soils, University of Massachusetts. October 16-19, 2000. Amherst, MA.
OGDEN
Introduction
• Environmental investigation of MMR
• Explosives primary contaminants of interest
• Over 1,500 surface soil samples collected
• Over 650 subsurface soil samples
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Site Location
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Background
• Acetone and MEK initially observed at low levels in 1997 using Method 5030 (< 20 ppb)
• Upon switch to Method 5035 (sodium bisulfate preservation) high levels of acetone and MEK observed ( > 100 ppb)
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Method 5030 Issues
• Significant volatilization loss
• Potential for biodegradation
• MADEP recognition of Method 5030 shortcomings resulted in adoption of Method 5035 in early 1999
OGDEN
Method 5035 Options
• Methanol Preservation
• Sodium Bisulfate Preservation
• Deionized water
• No preservative, special sampler
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Acetone in Project Samples
0200400600800
100012001400
7/14/9712/1
1/97 5/10/9810/7/98
3/6/99
8/3/99
12/31/995/29/00
Date
Ace
ton
e (u
g/k
g) Beginning ofSodium BisulfatePreservation
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Potential Acetone Sources
• Site contamination
• Matrix effect
• Instrument effect
• Laboratory cross-contamination
• Field contamination
• Chemical reactions in sample
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Incidental Sources of Acetone
• HPLC Grade Methanol - 11 and 14 ug/L
• Antifreeze - 360 ug/L
• Electrical Tape - 5 ug/L
• Ambient air in field - 6 ug/L
• Sharpies - 4 ug/L
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Acetone in Project Samples
0200400600800
100012001400
7/14/9712/1
1/97 5/10/9810/7/98
3/6/99
8/3/99
12/31/995/29/00
Date
Ace
ton
e (u
g/k
g) Beginning ofSodium BisulfatePreservation
OGDEN
Acetone Levels in Field Duplicates
0 200 400 600 800 1,000 1,2000
200
400
600
800
1,000
1,200
Dup
licat
e (u
g/kg
)
Original (ug/kg)
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Acetone in Site Samples vs Contact Time with Sodium Bisulfate
1 2 3 4 5 6 7 8 9 10 11 12 130
200
400
600
800
1,000
1,200
Time (Days)
Ace
tone
(ug
/L)
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Preliminary Evaluation
• Deionized Water
• Sodium Bisulfate
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Deionized Water Preserved Samples
1 2 3 4 5 60
100
200
300
400
500
600
Day 8 Day 14
Ace
tone
(ug
/kg)
Sample
X = 91
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Sodium Bisulfate Preserved Samples
1 2 3 4 5 60
100
200
300
400
500
Day 8 Day 14
Ace
tone
(ug/
kg)
Sample
X = 197
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Sodium Bisulfate Preservation Observations
• Increased frequency of detection of acetone and MEK
• Higher concentrations of acetone and MEK
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Soil Preservation Methods Evaluated
• No preservative (Method 5030)
• Deionized Water
• Frozen Deionized Water
• Sodium Bisulfate
• Sodium Bicarbonate
• Methanol
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Soil Properties
• Uncontaminated Site Soil w/ native plant materialOrganic Loam
Initial pH = 5.22
Moisture content = 19 %Sand
Initial pH = 6.00
Moisture content = < 10 %
• Control Sample - organic free sand
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Preservation Methods - Sand
1 3 7 14 21 280
5
10
15
20
25
30
35
ControlNon-preservedDIFrozenNa-BisulfateNa-BicarbonateMethanol
Acetone (ug/kg)
Time (days)
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Preservation Methods - Organic Loam
1 3 7 14 21 280
50
100
150
200
250
300
ControlNon-preservedDIFrozenNa-BisulfateNa-BicarbonateMethanol
Time (days)
Acetone (ug/kg)
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Multiple Regression Analysis
• Detected acetone concentrations may depend on° Concentration of organic carbon (OC) in the sample
• Sample holding time (HT) 490 samples analyzed for acetone
° 490 HT measurements
° 177 samples also analyzed for OC
• Distributions of acetone concentrations, OC concentrations, and HT appear skewed
• Log-transformed data were used in regression analysis
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Results of Simple Linear Regression
• Significant correlation between acetone and OC (p < 0.001)
° R2 = 0.16 (explains 16% of the variability in acetone concentrations)
• Significant correlation between acetone and HT (p < 0.001)
° R2 = 0.04 (explains 4% of the variability in acetone concentrations)
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Results of Multiple Regression Analysis
• Acetone = 2.43*[HT0.371]*[OC0.308]
• p < 0.001
• Adjusted multiple R2 = 0.22 (explains 22% of the variability in acetone concentrations)
• Holding time and organic carbon concentrations account for some of the variation in acetone concentrations
• Much of the variability remains unexplained
• Other variables may also influence acetone concentration
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Conclusions
• Acetone production appears related to organic content and may result from oxidation of natural occurring waxes or humic material
• If acetone is a potential site contaminant sodium bisulfate should not be used
• Freezing of samples may be a preferred alternative
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Recommendations
• EPA reevaluate the appropriateness of sodium bisulfate
• Study of plant material and aliphatic hydrocarbons
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