Beyond TPH - NEIWPCC
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Beyond TPH John Fitzgerald Massachusetts Department of Environmental Protection
Transcript of Beyond TPH - NEIWPCC
Beyond TPH
John Fitzgerald
Massachusetts Department of Environmental Protection
Characterizing Petroleum
Contamination
Source Migration
Screening: PID, TPH
ID/Detailed: GC, GC/MS
Risks Posed by Hydrocarbons
Impacts to
water supplies Vapor Intrusion
Direct Contact
w/ Workers
Direct Contact
w/ Children
Impacts to
Aquatic Life
How do we characterize Risks?
Test For/Focus on
Indicator Compounds
BTEX
PAHs
Test for/Focus on
“Total” Hydrocarbons
Gravimetric
Gas Chromatography
Ignores many
other
hydrocarbon
components
Method Defined
No/Limited Info on
Toxicity
Is there a better way?
…to quantify ALL hydrocarbons…
…in a risk-based manner?
…consistently
Hydrocarbon Range Approach
1994 MassDEP
1997 TPH Criteria Working Group
http://www.mass.gov/eea/docs/dep/cleanup/laws/tphtox03.pdf
• Petroleum is mostly made up of aliphatic and aromatic hydrocarbons
• Aromatic compounds are more toxic than aliphatic compounds
• The toxicity of aliphatic compounds is a function of molecular weight/number of carbon atoms
The Premise
• Break up TPH into collective fractions of
aliphatic and aromatic compounds
• Break up aliphatic fractions by carbon
number
• Assign a toxicity value to the fractions based
upon a well characterized “surrogate”
compound(s) contained within the fraction
The Concept
C11-C22
Aromatics
The Concept
C9-C18
Aliphatics
C19-C36
Aliphatics
BTEX &“Target” PAHs
Average Values from Data Set of 145 Soils Samples impacted by #2 Fuel
(MassDEP, 2007)
Toxicological Metrics [MassDEP]
Hydrocarbon Fraction
RfD (mg/kg/day)
RfC (mg/m3)
C5-C8 Aliphatics 0.04 0.2
C9-C18 Aliphatics 0.1 0.2
C19-C36 Aliphatics 2.0 NA
C9-C22 Aromatics 0.03 0.05
What about BTEX/Target PAHs?
Still Quantify and Evaluate Individually
Quantify Aliphatic and Aromatic
Hydrocarbon Fractions to Address
“The Rest of the Stuff”
Continuation of Tradition!
Addresses Carcinogenic Effects
Making it Work
Develop generic “Tier I” cleanup standards for aliphatic/aromatic fractions
Issue Implementation Guidance
Conduct training/outreach
Develop and validate analytical
methods to provide needed data 1995 -1998
1997
1997 & 2002
1995 to present
• Volatile Petroleum Hydrocarbons (VPH) – GC/PID/FID purge and trap technique
– PID selectivity to differentiate aliphatics from aromatics
• Extractable Petroleum Hydrocarbons (EPH) – extract loaded onto silica gel, rinsed with hexane to strip
“aliphatic” portion, then MeCl to strip “aromatic” portion
– both fractions analyzed separately via GC/FID
• Air-phase Petroleum Hydrocarbons (APH) – Aromatic Range via extracted ions 120 & 134 m/z
– Aliphatic Range via Total Ion Chromatogram
Analytical Methods (MassDEP)
$100
to
$125
$180
to
$200
$225
to
$275
So
il &
Gro
un
dw
ate
r A
ir/V
ap
or
Each Method also quantifies BTEX/PAH Target Analytes
JP4 Contaminated Soil
VPH by GC/FID/PID
Aliphatics &
Aromatics
GC/FID
Aromatics
GC/PID (10.2 eV)
IS - 2,4-Difluorotoluene
SS1 - Fluorobenzene
SS2 - 2-Fluorobiphenyl
QC Compounds (mod.)
1 - MtBE
2 - Benzene
3 - Toluene
4 - Ethylbenzene
5 - m/p-Xylene
6 - o-Xylene
7 - Naphthalene
Target Compounds
Time (min.) 0 10 20 30
IS
1
2
3
4
5
6
7
IS
SS1
SS2
7
6
5 3
4 2 1
C5-C8 Aliphatics C9-C12 Aliphatics
C9-C10 Aromatics
Diesel Contaminated Soil
EPH by GC/FID
Aromatics
GC/FID
Aliphatics
GC/FID
Target Analytes
1 - Naphthalene
2 - 2-Methylnaphthalene
3 - 1-Methylnaphthalene
4 - Acenaphthene
5 - Phenanthrene
1
3
2
4 5
IS1
IS1
IS2
IS2 SS1 SS2
SS3
SS4
Time (min)
300K
70K
0 10 20 30 40 50 60
C9-C18 Range Aliphatics C19-C36 Range Aliphatics
C11-C22 Range Aromatics
QC Compounds (mod.)
IS1 - 2,4-Dibromotoluene
IS2 - o-Terphenyl
SS! - 5a-Androstane
SS2 - 5a-Cholestane
SS3 - Fluorobenzene
SS4 - 2-Fluorobiphenyl
#2 Fuel Oil Vapors
APH by GC/MS
Extracted ions 120 m/z & 134 m/z used to quantify
C9-C10 Aromatic Hydrocarbons
Total Ion Chromatogram
• Developed for all aliphatic/aromatic fractions
• Developed for soil and groundwater
• Followed existing MassDEP approach
– soil stds address direct contact & leaching
– groundwater stds address ingestion,
aquatic, and volatilization concerns
Generic (Tier I) Standards
MassDEP “Direct Contact” Soil
Standards [mg/kg]
Fraction “Residential” “Industrial”
C5-C8 Aliphatics 100 500
C9-C12 Aliphatics 1000 5000
C9-C10 Aromatics 100 500
C9-C18 Aliphatics 1000 5000
C19-C36 Aliphatics 2500 5000
C11-C22 Aromatics 1000 5000
• Allows for Risk-Based “TPH” Clean Ups
• Works no matter what the product, or mixture
of products, or degree of weathering
• Relatively simple and cost effective
• Proven Track Record (1997 – Present)
Benefits of Approach
But Nothing is Perfect…..
The totality of procedures, assumptions, and standards
are designed to be reasonably but not excessively
conservative (health protective) at most petroleum
contaminated sites…but…
Especially with indoor air (APH) data….
Non-petroleum contaminant “background” can lead to
overly conservative results at some sites…
Air-Phase Petroleum Hydrocarbons (APH)
APH bias is more problematic than VPH/EPH tests on
soil and groundwater, given “background” stuff in indoor
air:
Fuel Oil/Gasoline if stored/used on-site
Common household chemicals
Potential Non-APH Compounds
C5-C8 Aliphatic
Hydrocarbons
Acetone may co-elute/interfere with isopentane.
Isopropyl alcohol, methyl ethyl ketone,
trichloroethene, tetrachloroethene, tetrahydrofuran,
hexanal, 1-butanol, hexamethylsiloxane
C9-C12 Aliphatic
Hydrocarbons
Terpenes (e.g., a-pinene, d-limonene), phenol,
benzaldehyde, n-chain aldehydes, 2-ethyl-1-
hexanol, siloxanes, dichlorobenzenes
C9-C10 Aromatic
Hydrocarbons
Siloxanes, a-pinene, and d-limonene may slightly
interfere if present at high concentrations (contribute
to the area of ions 120/134)
Air-Phase Petroleum Hydrocarbons (APH)
Table 7 of the MassDEP Method
Example – Fuel Oil Spill in Westfied, MA
Basement Air – APH Total Ion Chromatogram
IS BFB
p/m Xylenes
Very Low Fuel Oil
Hydrocarbons
Tolu
ene C5-C8
Hydrocarbons?
Example – Fuel Oil Spill in Westfied, MA
Basement Air – APH Total Ion Chromatogram
Ethanol
Ethyl
Acetate
Freons
MEK
PCE
And Similar Chromatogram for Second Floor
Take-Home Message
Need to look at Chromatograms!
Be aware of “background” organic
compounds that will be quantified as TPH
or Aliphatic/Aromatic Range Hydrocarbons
Contact Person - John Fitzgerald
To Learn/Download More
Google “Mass DEP VPH/EPH/APH”
