ASSOCIATIONS OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) WITH SIZE FRACTIONATED SEDIMENT PARTICLES Jejal Reddy Bathi, Geosyntec Consultants, Santa Barbara, CA -93110 Robert Pitt, The University of Alabama, Tuscaloosa, AL -35487 Shirley Clark, Penn State – Harrisburg, Middletown, PA- 17507
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ASSOCIATIONS OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) WITH SIZE FRACTIONATED SEDIMENT PARTICLES
ASSOCIATIONS OF POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) WITH SIZE FRACTIONATED SEDIMENT PARTICLES. Jejal Reddy Bathi, Geosyntec Consultants, Santa Barbara, CA -93110 Robert Pitt, The University of Alabama, Tuscaloosa, AL -35487 Shirley Clark, Penn State – Harrisburg, Middletown, PA-17507. - PowerPoint PPT Presentation
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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
ASSOCIATIO
NS O
F PAHS WITH SIZE FRACTIO
NATED
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)
ASSOCIATIO
NS O
F PAHS WITH SIZE FRACTIO
NATED
SEDIMEN
T PARTICLESSediment Sample Collection and Analyses
(especially, Auto Service Area next to the sampling location), Road Runoff, Residential Trailer Park Areas
ASSOCIATIO
NS O
F PAHS WITH SIZE FRACTIO
NATED
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
ASSOCIATIO
NS O
F PAHS WITH SIZE FRACTIO
NATED
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
ASSOCIATIO
NS O
F PAHS WITH SIZE FRACTIO
NATED
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
ASSOCIATIO
NS O
F PAHS WITH SIZE FRACTIO
NATED
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
NS O
F PAHS WITH SIZE FRACTIO
NATED
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
Probability Plots and One-Way ANOVA were used to compare the PAH concentrations at all three sites
ASSOCIATIO
NS O
F PAHS WITH SIZE FRACTIO
NATED
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)
ASSOCIATIO
NS O
F PAHS WITH SIZE FRACTIO
NATED
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