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A Risk-Based Approach to Identifying Contaminants of Most Concern from Oil Shale Development

Thomas R. Wood, Carl D. Palmer, Earl Mattson

30th Oil Shale Symposium October 18-22, 2010 Idaho National Laboratory

Objective:

To determine which contaminants are likely to be of most concern with regard to in-situ oil shale development.

Approach:

• Identify contaminants reported from laboratory

leaching tests and from groundwater sampling at field retort tests,

• Estimate the relative toxicity of the contaminants,
• Estimate the mobility of those contaminants.

Linder-Lunsford (1990) MFG Environmental (2006) Benton (1992) Organics Inorganics MFG Environmental (2006) Palmer and Mattson (Unpublished data) Parker et al. (1976) Linder-Lunsford (1990) Benton (1992) Fox (1979) Jackson et al. (1975)

Groundwater Contaminant Data Sources

• phenols (2,4-dimethylphenol)
• ketones (2-butanone)
• alcohols (2-ethyl-2-hexanol)
• rganic acids (benzoic acid)
• aromatics (benzene)
• nitrogen compounds (pyridine)
• alkanes (trimethylcyclohexane)
• PAHs (phenanthrene)
• halogenated compounds (tribromophenol)

79 Reported Compounds

Organic Contaminants

• pH
• Metals (Zn, Ni)
• Alkali/Alkaline Earths (Na+, K+, Ba2+)
• Nitrogen compounds (NH4

+)

• Sulfur compounds (SO4

2-, S2-)

• Halides (Cl-, Br-, F-)
• Oxyanions (Sb, B)
• Rare Earth Elements (Zr, Y)
• Cyanide
• Uranium

70 Reported Compounds

Inorganic Contaminants

Estimate “Toxicity”

• obtain maximum reported aqueous concentration (Cmax),
• determine some “safe” contaminant concentration (CMCL)
• drinking water standards (EPA)
• secondary drinking water standards (EPA)
• state drinking water standards/guidelines
• foreign drinking water standards/guidelines (Canada,

UK, EU)

• Identify (e.g., from ATSDR) an oral Maximum Risk

Level (MRL) or similar criterion (in mg/kg/day) and multiply by 45 kg, divide by 3.7 L/day, and divide by 10.

• divide Cmax by CMCL

• Estimate retardation factor
• Mobility = 1/R

Estimating “Mobility”

1

b p w

R K ρ θ = + = +

s p aq

C K C =

p

• c
• c

K f K =

retardation factor soil partition coefficient fraction of organic carbon in soil partition coefficient between aqueous phase and soil carbon phase

p

• c
• c

R K f K = = = =

Aqueous Concentration (mg/L)

0.0 0.1 0.2 0.3 0.4 0.5 0.6

Sorbed Concentration (mg/g)

4 6 8 10 12 14

Phenanthrene Sorption

• nto Green River Kerogen

Data from Salloum et al. (2002)

Kp = 15631 ±814 mL/g Koc = 43662 ±2273 mL/g

Neutral, hydrophobic organic compounds

1

b p w

R K ρ θ = + = +

p

• c
• c

K f K =

retardation factor soil partition coefficient fraction of organic carbon in soil partition coefficient between aqueous phase and soil carbon phase

p

• c
• c

R K f K = = = =

PYRENE PHENANTHRENE

K

p

P Y R E N E ( m L / g )

1800 1500 1200 900 600 300 0.005 0.0 0.010 0.015 0.020 0.025

FRACTION ORGANIC CARBON

K

p

P H E N A N T H R E N E ( m L / g )

600 500 400 300 200 100

Slope = Koc

(Karickhoff, 1981)

Neutral, hydrophobic organic compounds

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7

Log Kow Log Koc

Data from Karickhoff (1981)

Empirical and Structure- based relationships between Koc and the

• ctanol-water partition

coefficient (Kow)

Neutral, hydrophobic organic compounds

Log(Cmax/CMCL)

• 2
• 1

1 2 3 4

Log(1/R)

• 6
• 4
• 2

High Toxicity, High Mobility High Toxicity, Low Mobility Low Toxicity, Low Mobility Low Toxicity, High Mobility

Toxicity and Mobility

Log(Cmax/CMCL)

• 2
• 1

1 2 3 4

Log(1/R)

• 6
• 4
• 2

Organic Compounds

Benzidine Pyrrole Benzene 2-Methylnaphthalene 1-Methylnaphthalene Isophorone 2-Butanone Chloroethane Aniline 2-pyrrolidone 2-methylphenol vinyl chloride 3- and 4- Methylphenol Bromomethane acetonitrile 4-methylphenol Phenol Acetone Thiophene 2-Hexanone

Organic Compounds of Most Concern

1,1,3 trimethyl Cyclohexane 6-octen-2-one 1,3 dihydro 2-H-Indol, 2-one 7-octen-2-one 2(1,1-dimethlethyl)-3-methyl oxirane Beta-citronellol 2,6 dimethyl 5-hepten-1-o1 decahydro-1-methyl quinoline 3,3-dimethyl butanoic acid dihydro-5-methyl 2(3H)-furanone 3-ethyl, 4-methyl, 2,5 furandione dihydro-5-propyl furanone 3-methyl Bicyclo[4,1,0]heptane Ketones (sum) 3-methyl cyclopentacarbonic acid N-ethyl-4-methyl benzensulfanilimide 4,4,6-trimethyl 2-cyclohexen-1-one trans-1, 6-dimethylbicyclo[4.3.0]nonan 4-ethyl, 3-heptene N-methyl ethanamine 4-hepten-2-ol Methane 4-Methyl-2-pentanone Ethene 5-chloro-2-2hydroxy Benzaldehyde 1-H-Benzotrizole 5-methyl 1-hepten Pentanoic acid 5-methyl-2(1-methylethyl) cyclohexanol hexanoic acid 6-methyl 2-heptanone

Organic Compounds of Potential Concern

Chlorobenzenes

1/T

0.0031 0.0032 0.0033 0.0034 0.0035 0.0036 0.0037

log (Kow)

2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0

Hexa- 1,3,5-tri- 1,2-di

Data from Bahadur et al.,1(997)

Similar results for monoterpenoids (Copolovici and Niinemets, 2005) and sulfonamides (Congliang, et al. (2007).

Temperature Dependence of Log(Kow)

Log(Cmax/CMCL)

• 2
• 1

1 2 3 4

Log(1/R)

• 6
• 4
• 2

Inorganic Compounds

Ammonia Cyanide Sulfide Sulfate Boron Chloride Sodium Mercury iodide Vanadium Carbon disulfide Nitrite (N) Aluminum thiosulfate Fluoride thiocyanate TDS

Inorganic Compounds of Most Concern

Bicarbonate tungsten Magnesium praseodymium Total Alkalinity lanthanum Oil and Grease neodymium Total Organic Carbon germanium COD gallium Bromide titanium lithium scandium

Inorganic Compounds of Potential Concern

Summary

We have

• Obtained data (field and laboratory) on maximum

concentrations associated with leaching of spent oil shale,

• Considered the risk of these contaminants based on their

relative mobility and toxicity,

• Created an initial prioritized list of contaminants that

should be considered,

• Identified potential contaminants that require additional

information.

Limitations with the Approach

• Use of maximum observed concentrations,
• How to include frequency of occurrence,
• Insufficient guidelines for MCLs,
• Lack of octanol/water partition data,
• Partition coefficients are a function of temperature,
• Have not included potential biodegradation,
• Have yet to include potential mineral precipitation,
• Potential for colloidal transport,
• Additional difficulties with fracture flow.