ACS_Fa2003 WSU-TC

Solid Phase Extraction (SPE)/GC-ECD Analysis for Polychlorinated Biphenyls (PCBs) in Real Liquid Hanford Nuclear

Waste Samples

Asopuru Okemgbo

Washington State University Tri-Cities 2710 University Drive, Richland, WA 99352

American Chemical Society National Conference, September 7-11, 2003

ACS_Fa2003 WSU-TC

To evaluate sample preparation method for the determination of polychlorinated biphenyls (PCBs) in Hanford nuclear waste that would – Significantly reduce the volume of waste generated during

analysis.

– Eliminate methylene chloride as a solvent for the extraction of PCBs.

– Lower detection limit and meet regulatory requirements for PCB

– Reduce radiation exposure of analysts.

2Research Objectives

ACS_Fa2003 WSU-TC

Hanford Tank Waste

– Nuclear waste accumulated between1944 and 1987 was one of the aftermaths of World War II and Cold War nuclear bomb production.

– It is the biggest US environmental restoration, waste management, and waste treatment project.

Tank Safety, Closure Programs & River Protection Project

– Risk issues, research & resolution.

– Regulatory requirements.

– A $5.8 billion DOE Waste Treatment Project.

Hanford Site Background Information

3

ACS_Fa2003 WSU-TC

Hanford Underground Tanks 4

•149 Single Shell Tanks (SST’s)- Built 1943-1964.- Capacity of 55,000 to 1 million gal.

• 28 Double Shell Tanks (DST’s)- Built 1966-1986.- Capacity of 1.25 million gal. each.

• Contain about 54 million gal. Waste.

ACS_Fa2003 WSU-TC

5What the Tank waste looks like

Supernate Sludge

Saltcake

177 Hanford Tanks Waste Composition by Volume

Sludge

Saltcake

Supernatant

20%

34%

46%

Ref: HNF-EP-0182, Rev. 179

ACS_Fa2003 WSU-TC

6Waste Treatment Process

ACS_Fa2003 WSU-TC

Tank Safety Issues Criticality & Corrosivity Drivers

Regulatory Characterization Tri-Party Agreement. Nuclear regulations.

Waste Treatment Plant Needs Contract & Process Drivers.

Overview of Characterization at Hanford

7

ACS_Fa2003 WSU-TC

Analytical challenges are due but not limited to

High ionic strength. Large number of analytes & degradation

products. Caustic matrices. High radiation levels. Matrix interference. Inadequate EPA Sample Prep Methods for

Regulatory Analyses.

8Challenges of Hanford Waste Characterization

ACS_Fa2003 WSU-TC

Waste characterization challenges

Radioactivity constraints Sample Handling - Dose rate. Remote Hot Cell techniques. Blank contamination.

Matrix Problems RSD/RPD failures. Matrix spike failures.

9Challenges in Hanford Waste Characterization

ACS_Fa2003 WSU-TC

10Challenges in Hanford Waste Characterization

• Sample size limitations

High MDL in real waste.

EQL/MRQ failures.

Dose rate issues.

ALARA requirements.

ACS_Fa2003 WSU-TC

11SW-846 Methods

EPA Methods for Organic Constituents

8081A, Organochlorine Pesticides by Gas Chromatography (GC)/Electron Capture Detector (ECD)

8082, Polychlorinated Biphenyl (PCBs) by GC/ECD

8151A, Chlorinated Herbicides by GC

8260B, Volatile Organic Analysis (VOA) by GC/Mass Spectrometry (MS)

8270C, Semivolatile Organic Analysis (SVOA) by GC/MS

The associated Sample Prep Methods are the real issues!

ACS_Fa2003 WSU-TC

12CURRENT PCB EXTRACTION METHODS AT 222-S

Aqueous Samples: Continuous liquid-liquid extraction (LLE). Solid Samples: Soxhlet extraction.

Disadvantages and Limitations• Interference problems• Uses hazardous organic solvents such as methylene chloride• Large volume of mixed radioactive waste generated • Laborious • Time consuming• High costs

ACS_Fa2003 WSU-TC

13SPE STRATEGY & CONDITIONS

SPE Sorbent: Varian’s Bond Elut, 200mg

Extractor: Positive Pressure Manifold

Sample Size: 1.0 to 10.0 mL

Spike levels: 0.01 to 500 ug/L aroclors 1016 and 1260.

Eluent: Hexane

Sample treatment: 25% sodium nitrate added to increase ionic strength for preferential sorption of PCBs

GC Conditions: EPA SW-846 Method 8082

ACS_Fa2003 WSU-TC

14Analytical Results

Evaluation SPE of 1% Synthetic Hanford Waste in 25% nitrate spiked with 40 g/L TCX, DCB, Aroclor

1016/1260

Compound % Recovery %RSD MDL(g/L)

TCX 75 12 8.9DCB 113 6 6.2Aroclor 1016 94 3 2.9Aroclor 1260 106 3 2.8

Surrogates: TCX – Tetrachloro-m-xylene, DCB – Decachlorobiphenyl

ACS_Fa2003 WSU-TC

15Analytical Results

Evaluation SPE of 10% Synthetic Hanford Waste in 25% nitrate spiked with 40 g/L TCX, DCB,

Aroclor 1016/1260

Compound % Recovery RSD MDL (g/L)

TCX 80 10 7.5DCB 109 12 10.8Aroclor 1016 96 5 6.9 5.0Aroclor 1260 93 6 5.3 5.3

ACS_Fa2003 WSU-TC

EVALUATION OF INTERFERENCES* IN SIMULATED SY-101LIQUID WASTE AT VARIOUS SPIKE LEVELS

DCP AROCLOR 1016 AROCLOR 1260SAMPLE SPIKE(ppb) 31.67

min15.47min

14.53min

23.88min

25.89min

SY-101 10.0 152% 104% 104% 123% 120%SY-101 100.0 115% 99% 127% 120% 104%SY-101 500.0 104% 91% 98% 110% 82%

* A mixture containing 1 ppm of each: carbon tetracholride, dibutyl phosphate,tributyl phosphate, dibutyl butylphosphonate, decane, tridecane, and tetradecane.

Analytical Results 16

ACS_Fa2003 WSU-TC

Analytical Results

Chromatogram of Real Hanford Tank Waste Spiked with PCBs

17

ACS_Fa2003 WSU-TC

Evaluation SPE of Real Hanford Tank Waste Spiked with TCX, DCB, Aroclor 1016/1260

Test Sample % TCX % DCB % Ar1254

Acceptable % 26-87 % 27-123 % 51-128 %

Check Standard 97 101 92

Tank Waste 29 61 -

Spike 29 29 49

Analytical Results 18

ACS_Fa2003 WSU-TC

Conclusions 19

Solid Phase Extraction was found to be efficient for the

extraction of PCBs in Hanford Nuclear Waste. Addition of 25% sodium nitrate favored selective extraction

of PCBs in the presence of potential competing organic compounds.

Very low sample size has the desired reduction of radiation

dose & ALARA principles. Elimination of methylene chloride is huge contribution to

reduced health risks to the analysts. Regulatory requirements are achievable.

ACS_Fa2003 WSU-TC

Mikhail Arinbasarov

Centre of Instrumental Methods of Analysis Institute of Biochemistry and Physiology of Microorganisms Pushchino, Moscow region, Russia.

Ed Rykiel

Washington State University Tri-Cities. Steve Metcalf & Jerry Kunkel

222-S Laboratory, Hanford Site, WA. Len Pingel

Waste Sampling and Characterization Facility

Hanford Site, WA.

Acknowledgements 20