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

OGDEN

Site Location

OGDEN

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)

OGDEN

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

OGDEN

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

Potential Acetone Sources

• Site contamination

• Matrix effect

• Instrument effect

• Laboratory cross-contamination

• Field contamination

• Chemical reactions in sample

OGDEN

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

OGDEN

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)

OGDEN

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)

OGDEN

Preliminary Evaluation

• Deionized Water

• Sodium Bisulfate

OGDEN

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

OGDEN

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

OGDEN

Sodium Bisulfate Preservation Observations

• Increased frequency of detection of acetone and MEK

• Higher concentrations of acetone and MEK

OGDEN

Soil Preservation Methods Evaluated

• No preservative (Method 5030)

• Deionized Water

• Frozen Deionized Water

• Sodium Bisulfate

• Sodium Bicarbonate

• Methanol

OGDEN

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

OGDEN

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)

OGDEN

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)

OGDEN

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

OGDEN

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)

OGDEN

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

OGDEN

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

OGDEN

Recommendations

• EPA reevaluate the appropriateness of sodium bisulfate

• Study of plant material and aliphatic hydrocarbons

OGDEN