ASSOCIATIONS OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) WITH SIZE
FRACTIONATED SEDIMENT PARTICLES
Jejal Reddy Bathi, Geosyntec Consultants, Santa Barbara, CA -93110Robert Pitt, The University of Alabama, Tuscaloosa, AL -35487Shirley Clark, Penn State – Harrisburg, Middletown, PA-17507
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SEDIMEN
T PARTICLESIntroduction
• Non-point sources are major contributors of PAHs to the environment (US EPA 2000)• PAHs predominantly associate with solids (low solubility and are hydrophobic)• Adsorption on particulate matter is the main transport and fate mechanism of PAHs in the environment • Understanding the distribution of contaminants with particle sizes is needed for effective and economical treatment of PAHs in runoff• Contributing source areas affect the magnitude of PAH concentrations with particles (USGS 2003)
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SEDIMEN
T PARTICLESSediment Sample Collection and Analyses
• Sampling Location 1: Cribbs Mill Creek• Major Contributing Source Areas: Residential
Area• Samples were collected at the end of a
concrete channel
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SEDIMEN
T PARTICLESSediment Sample Collection and Analyses
• Sampling Location 2: Hunter Creek• Major Contributing Source Areas: Commercial
(especially, Auto Service Area next to the sampling location), Road Runoff, Residential Trailer Park Areas
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SEDIMEN
T PARTICLESSediment Sample Collection and Analyses
• Sampling Location 3: Carroll’s Creek• Major Contributing Source Areas: Residential and
Commercial areas• Had past history of sanitary sewage contamination from
SSOs
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SEDIMEN
T PARTICLESSediment Sample Collection and Analyses
• Different particle sizes (< 45µm to >2800µm) of each creek sediment sample were analyzed separately for PAH contamination
• Large Organic Material (LOM) were separated from >2800 um size fraction for separate analyses
• All size fractions were analyzed for Material Composition and Chemical Oxygen Demand (COD)
• Sediments were analyzed for PAHs by Thermal Desorption (TD) extraction followed by Gas Chromotoraphy – Mass Spectroscopy (GC-MS) detection
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SEDIMEN
T PARTICLESParticle Size Distribution
• For all cases, the particles in the size range of 180 to 355 µm were dominant in the sediments. Overall, most of the particles were distributed in the size range of 90 to 710 µm.
0102030405060708090
100
10 100 1000 10000Size (um)
% L
ess
than
Hunter Creek Cribbs Mill Creek Carroll's Creek
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SEDIMEN
T PARTICLESChemical Oxygen Demand
COD
(mg/
Kg)
210000000
180000000
150000000
120000000
90000000
60000000
30000000
0
Size range (µm)
Cribb's Creek
0
20
40
60
80
100
10 100 1000 10000Size (um)
% o
f tot
al C
OD
less
than
Hunter Carroll's Cribbs Mill Average of all
COD
(mg/
Kg)
175000000
150000000
125000000
100000000
75000000
50000000
25000000
0
Hunter Creek
Size range (µm)CO
D (m
g/Kg
)
175000000
150000000
125000000
100000000
75000000
50000000
25000000
0
Carroll's Creek
Size range (µm)
• For all cases, sediment CODs showed similar distribution
• The COD values of the >2800µm (LOM only) was 1.3 to 1.6E09 mg/kg
• Median particle size based on COD was about 355µm for three creeks
ASSOCIATIO
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SEDIMEN
T PARTICLESMaterial Composition
02468
101214161820
Size Range (µm)
% o
f W
eigh
t Los
s
Hunter Carrol l 's Cribb's
02468
1012141618
Size Range (µm)
% O
f Wei
ght L
oss
Hunter Carroll 's Cribbs
Temp. (oC)
Material Lost at These Temperatures
up to 104 Moisture104 - 240 Paper debris240 - 365 Leaves and grass365 - 470 Rubber470 - 550 AsphaltAbove 550
Remaining material is inert
Temperature
Range (ºC)
LOM % Weight Loss
HunterCarroll
's104 - 240 8.6 20.4240 - 365 42.5 33.5365 - 470 28.3 3.9470 - 550 1.3 0.9% Inert Material 19.2 41.4
Temperature range of
240˚C – 365 ˚C
Temperature range of 104 – 550 °C
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SEDIMEN
T PARTICLES2-Way ANOVA of PAH Concentrations for Particle Size and Location
PAHP Value
Size Location Size*Location
Naphthalene 0 0.088 0.116
Fluorene 0 0.721 0.481
Phenanthrene 0 0.389 0.043
Anthracene 0 0.032 0.821
Fluranthene 0 0 0
Pyrene 0 0 0
Benzo(a)anthracene 0 0.005 0.002
Chrysene 0 0.004 0
Benzo(b)flouranthrene 0 0.002 0.254
Benzo(a)pyrene 0.004 0.032 0.022
Indeno(1,2,3-cd)pyrene 0 0.284 0.25
Dibenz(a,h)anthracene 0 0.019 0.002
Benzo(ghi)perylene 0 0.041 0.493
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SEDIMEN
T PARTICLESEffects of Particle Sizes and Location on PAH Concentrations
PAHP Value
Cribbs Mill Creek
Hunter Creek
Carroll's Creek
Naphthalene 0.324 0.000 0.000
Fluorene 0.000 0.000 0.000
Phenanthrene 0.000 0.000 0.000
Anthracene 0.000 0.000 0.000
Fluoranthrene 0.000 0.000 0.000
Pyrene 0.000 0.000 0.000
Benzo(a)anthracene 0.000 0.000 0.000
Chrysene 0.000 0.001 0.000
Benzo(b)flouranthrene 0.000 0.011 0.000
Benzo(a)pyrene 0.039 0.060 0.000
Indeno(1,2,3-cd)pyrene 0.002 0.437 0.000
Dibenz(a,h)anthracene 0.024 0.010 0.000
Benzo(ghi)perylene 0.004 0.118 0.565
31.18
54.12
77.06
100.00
Observations
Sim
ilarit
y
Benzo(a)anthracene
Cluster Analyses
Cluster analyses of analyte concentrations showed that > 2800µm (LOM only) fractions were separated as a single group distinct from the other size
categories at the 75th percent similarity level
for most PAH compounds for most
sites
One-Way ANOVA of PAH Concentrations by Particles
The PAH concentrations
in the >2800µm
(LOM only) fractions were several times
higher than for the other
sample sizes and are not
shown
900080007000600050004000300020001000
0
Size Range (µm)
Conc
entr
atio
n (µ
g/Kg
)Naphthalene
3500
3000
2500
2000
1500
1000
500
0
Size Range (µm)
Conc
entr
atio
n (µ
g/Kg
)
Fluorene
4000
3000
2000
1000
0
Size Range (µm)
Conc
entr
atio
n (µ
g/Kg
)
Anthracene
Leaves
> 2800
1400 -
2800
710 - 1
400
355 - 7
10
180 - 3
55
90 - 1
8045
- 90< 45
7000
6000
5000
4000
3000
2000
1000
0
Size Range (µm)
Conc
entr
atio
n (µ
g/Kg
)
Dibenz(a,h)anthracene
Leaves
> 2800
1400 -
2800
710 - 1
400
355 - 7
10
180 - 3
55
90 - 18
045
- 90
< 45
80007000
60005000
4000
30002000
1000
0
Size Range (µm)
Conc
entr
atio
n (µ
g/Kg
)
Benzo(g,h,i)perylene
4000
3000
2000
1000
0
Size Range (µm)
Conc
entr
atio
n (µ
g/Kg
)
Indeno(1,2,3-cd)pyrene
Concentrations of PAHs by Particle
Sizes
Almost all of the stream sediment
PAHs are associated, by mass, in the intermediate particle size
fraction (90 to 710 µm), even though
this size range had the lowest
concentrations
Leaves
> 2800
1400 -
2800
710 - 1
400
355 - 7
10
180 - 3
55
90 - 1
8045
- 90< 45
30000
25000
20000
15000
10000
5000
0
Size Range (µm)
% M
ass
Asso
ciatio
n w
ith S
edim
ent
Naphthalene
Leaves
> 2800
1400 -
2800
710 - 1
400
355 - 7
10
180 - 3
55
90 - 1
8045
- 90< 45
25000
20000
15000
10000
5000
0
Size Range (µm)
% M
ass
Asso
ciatio
n w
ith S
edim
ent
Fluorene
20000
15000
10000
5000
0
Size Range (µm)
% M
ass
Ass
ocia
tion
with
Sed
imen
t
Anthracene
35000
30000
25000
20000
15000
10000
5000
0
Size Range (µm)
% M
ass
Asso
ciatio
n w
ith S
edim
ent
Dibenz(a,h)anthracene
Leaves
> 2800
1400 -
2800
710 - 1
400
355 - 7
10
180 - 3
55
90 - 18
045
- 90
< 45
50000
40000
30000
20000
10000
0
Size Range (µm)
% M
ass
Asso
ciatio
n w
ith S
edim
ent
Benzo(g,h,i)perylene
Leaves
> 2800
1400 -
2800
710 - 1
400
355 - 7
10
180 - 3
55
90 - 18
045
- 90< 45
35000
30000
25000
20000
15000
10000
5000
0
Size Range (µm)
% M
ass
Asso
ciatio
n w
ith S
edim
ent
Indeno(1,2,3-cd)pyrene
Mass of PAHs by Urban Stream
Sediment Particle Sizes
Size (µm)% Average dry weight
of Sediment
<45 1.1
45 – 90 2.8
90 - 180 14.4
180 - 355 46.4
355 - 710 27.4
710 - 1400 3.51400 - 2800 1.8
Large organic matter
0.3
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SEDIMEN
T PARTICLESEffect of Land Use on PAH Pollution
Size Range (µm)
Cribbs Mill Creek Hunter Creek Carroll’s Creek
< 45Phenathrene
(Low),Benzo(ghi)peryl
ene (High)
Fluoranthrene (High), Pyrene (High) Benzo(a)anthracene (High), Chrysene (High), Benzo(a)pyrene (High),
Pyrene (Low), Benzo(a)anthracene
(Low), Benzo(b)flouranthrene
(Low),
45 - 90Phenathrene
(Low)
Fluorene (High), Fluoranthrene (High), Pyrene (High),
Benzo(a)anthracene ( High), Chrysene (High),
Benzo(b)flouranthrene (High)
Benzo(a)anthracene (Low),
90 – 180 NoneNaphthalene (Low),
Fluoranthrene (High), Pyrene (High)
Anthracene (Low), Fluoranthrene (Low)
180 - 355 None Fluoranthrene (High) None355 - 710 None Fluoranthrene (High) None
710 – 1400 None None Fluoranthrene (Low)
1400 - 2800 None None Fluoranthrene (Low)
> 2800 (w/o
LOM)None None None
> 2800 (LOM only)
None None None
Probability Plots and One-Way ANOVA were used to compare the PAH concentrations at all three sites
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SEDIMEN
T PARTICLESPower Analysis
• With COVs of 0.5 to 0.7 and 5 samples in each category, differences of about 100%, and larger, can be detected
• For smaller COVs, it is possible to detect smaller differences with same sampling effort (e.g. COV of 0.3 and with 5 samples, differences of about 40% could be detected)
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SEDIMEN
T PARTICLESConclusions
•The highest PAH concentrations were associated with stream sediment samples that had the highest organic content•Most of the mass of the PAHs were associated with the intermediate particle sizes (90 – 710µm) in the stream sediments which were in the greatest abundance, even though their PAH concentrations were the lowest•The site with the highest concentrations of most of the PAHs in the stream sediments was affected by obvious hydrocarbon contamination from adjacent commercial automobile service facilities• The one year since the SSO contamination, and bed erosion material possibly diluting the sediments at Carroll’s Creek, likely resulted in those samples being less contaminated compared to the other creek locations
