GL
00861
REPORT ID THE U.S. ENVIRONMENTAL PROTECTION AGENCY
on
ATMOSPHERIC DEPOSITION WORKSHOP ON ORGANIC CONTAMINANT DEPOSITION
TO THE GREAT LAKES BASIN
held at the UNIVERSITY OF MINNESOTA. MINNEAPOLIS
20-21 NOVEMBER. 1985
STEVEN J. EISENREICH
ENVIRONMENTAL ENGINEERING PROGRAM
DEPARTMENT OF CIVIL AND MINERAL ENGINEERING
UNIVERSITY OF MINNESOTA
MINNEAPOLIS, MINNESOTA 55455
PROJECT OFFICER
EDWARD KLAPPBNBACH
U. S. EPA
GREAT LAKES NATIONAL PROGRAM
536 S. CLARK ST.
CHICAGO, IL 60605
GRANT No: EPA/R005879-0
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"IT IS OFTEN NECESSARY TO HAKE A DECISION BASED
ON INFORMATION WHICH IS SUFFICIENT FOR ACTION
BUT INSUFFICIENT TO SATISFY THE INTELLECT
Enanual Kant .1786
" Critique of Pure Reason*
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PAGE
TABLE OF CONTENTS 1
EXECUTIVE SUMMARY 2
WORKSHOP OBJECTIVES 5
ATMOSPHERIC DEPOSITION PROCESSES 7
WET DEPOSITION
DRY PARTICLE DEPOSITION
VAPuR EXCHANGE Ai THE AIR-WATER INTERFACE
GREAl LAKES ATMOSPHERIC DEPOSITION NETWORK 18
RECOMMENDATIONS FOR A GREAT LAKES ATMOSPHERIC 20
INPUT AND SOURCES (GLAIS) NETWORK
GENERAL RECOMMENDATIONS
SPECIFIC RECOMMENDATIONS
REFERENCES 29
APPENDICES 31
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EXECUTIVE SUMMARY
An "Atmospheric Deposition" Workshop was held at the University of
Minnesota, Minneapolis on 20-21 November, 1985 under the support and
auspices of the Great Lakes National Program Office (GLNPO) of the
U.S. Environmental Protection Agency (EPA). Participants at the
wortsuop included distinguished scientists knowledgeable in
atmospheric processes from the U.S. and Canada, representatives of the
Canadian and U.o. organizations conducting monitoring studies and
staff of the GLNPO. The objectives of the workshop were two-fold:
(1) to review the Great Lakes atmospheric deposition network (GLAD)
presently operated by EPA; and (2) to make recommendations as to the
design and strategy for a new or modified network capable of assessing
atmospheric deposition of selected toxic chemicals to the Great lakes,
identify sources and quantify source strengths. These objectives are
meant to assist in the successful achievement of the goals stated in
EPA's five-year stategy relative to atmospheric deposition: (1) to
determine the portion of total loadings of critical toxic pollutants
by atmospheric deposition; (2) to recommend the extent to which
additional remedial programs and international activities are needed
to control atmospheric sources; ana (J) to provide source information
for immediate regulatory actiun.
A thorough review of the present GLAD network and accumulated data on
precipitation concentrations conclusively sno»ea that the GLAD network
as presently constituted is not adequate to provide needed data on
atmospheric inputs of toxic chemicais to the Great Lakes. This
conclusion was basea on siting, sample collection and data analysis
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criterea.
A detailed discussion of the processes of wet deposition, dry particle
deposition and vapor exchange at the air-water interface was held to
acquaint all present with the state-of-the-art in these areas. These
discussions led to the generation of recommendations on the structure
and design of a monitoring network capable of assessing atmospheric
inputs of toxic chemicals to the Great Lakes. The design strategy for
the network is to combine both deposition measurement and modeling to
assess atmospheric deposition. It would have relatively few sites
(e.g.* 16) at which collection of wet precipitation, air particles and
meteorological data necessary for the modeling effort wouid occur.
Two to four of these sites would be designated as master sites where
calibrations, intercomparison studies and research would be carried
out. Sites would be distributed in such a way as to estimate
"regional* deposition ( half of the sites) and "urban" deposition
since it is believed that intense episodes of localized inputs occur
in areas adjacent to population centers. If possible, monitoring
stations should be located on in-lake islands. A complete list of
instrumentation common to all sites is proviaeu in the text but
includes wet-only precipitation samplers capable 01 isolating the
analyte in the field, multiple Hi-Vol samplers operating to provide
directional data on atmospheric concentrations, and a suite of sensors
to measure meteorological parameters such as temperature profiles,
relative humidity, total suspended participates (TSP), and wind speed
and direction. Additional instrumentation to be located at the master
sites are cascade impactors and any necessary to support the research
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component. Toxic organic species to be monitored are polychlorinated
biphenyls (PCBs), routine organochlorine pesticides and industrial
chemicals, polycyclic aromatic hydrocarbons (PAHs), Hg, Pb and Cd.
tozaphene and generic chlorinated diozins and furans. Analysis of
these toxic chemicals will require considerable analytical support. It
is anticipated that this network woulu largely replace the larger GLAD
network. The research component of this network should include a
significant effort to quantify dry deposition and vapor exchange ox
both inorganic and organic toxic species through a combination of
sampling and modej.ing of over-late processes. Other methods of
assessing atmospheric inputs should be continued (e.g., mass balance!
small lake studies; sediment and peat profiles). Every attempt should
be made to integrate the D.a. network with Canadian efforts using
similar samplers and strategies, inter-calibrations and co— located
sampling sites to implement an "Integrated Atmospheric Deposition
Network". A rigorous QA/QC system need be instituted at the outset of
the project to ensure the quality of the data.
It is proposed that a multi-investigator study be performed in
the summer and winter of 198a to integrate deposition data generated
at the master sites with intensive over-lake measurements involving
wet deposition, dry deposition, vapor exchange and source
reconciliation.
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2.0 Workshop Objectives
The Great Lakes National Program Olfice (GLNPO) of the U.S.
Environmental Protection Agency (EPA) presently operates a 36 site
atmospheric monitoring networ*. (GLAD), of which 10 sites are equipped
with bulk samples for assessing organic contaminant deposition to the
Great Lakes.
The atmospheric deposition program for the next five years has
three objectives as stated in EPA's 5-year strategy document (1):
(1) to determine the portion of total loadings of critical toxic
pollutants by atmospheric deposition;
(2) to recommend the extent to which additional remedial
programs and international activities are needed to control
atmospheric sources;
(3) to provide source information for immediate regulatory
action.
The objectives 01 the -'Atmospheric Deposition" workshop held at
the University of Minnesota on the 20 and 21 November 1985 under the
auspices ot tne liLNPO 01 EPA were:
(1) to review the atmospheric deposition monitoring network
(CiLAD) operated by the GLNP;
(2) to make recommendations as to the design and strategy for a
new or modified atmospheric deposition network capable of
assessing atmospheric deposition of selected toxic organic
contaminants to the Great Lakes, identify sources and
quantify source strengths.
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Essential to this discussion was a thorough review of the
feasibility and limitations of assessing wet and dry deposition. To
these ends, the first part ox the workshop dealt with an overview of
the present GLAD netwwr~ by T.C. Hnrpity iDeFaul University) and D.
Gatz (Illinois State Water Survey). Based on a study recently
completed for EPA, T.C. Hurpny outlined requirements for a new Great
Lakes atmospheric and sources (GLAIS) network. These presentations
were followed by detailed discussions on the processes of atmospheric
deposition led by J. Pankow lOregon Graduate Center) on wet deposition
of organic species, A. Andren (University of Wisconsin) on dry
particle deposition of organic species. M. Weseley (Argonne National
Laboratory) on meteorological aspects of dry deposition, and T.
Bidleman (University of South Carolina) and S. Eisenreich (University
of Minnesota) on vapor-particle partitioning in the atmosphere and
volatilization, respectively. The remainder of the workshop involved
generating specific recommendations for measurement and assessment of
atmospheric deposition of organic contaminants to the Great Lakes.
Specific questions addressed throughout the workshop were:
(1) What is the relative importance of atmospheric deposition
compared to other input pathways for specific contaminants
in the Great Lakes Basin and specific Great Lakes?
(2) What are the important deposition processes and how coulu
they be quantified?
(3) What of the thousands of organic chemicals produced and
released to the environment need be measured and how?
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(4) What are the atmospheric sources and source strengths for
specific organic contaminants?
(5) What are the characteristics of an atmospheric deposition
ne twork
wnich is adequate to provide needed data?
(6) What are the research needs to support the atmospheric
deposition network?
3.0 Atmospheric Deposition Processes
Atmospheric organic chemicals exist in the vapor phase and
adsorbed to suspended particles (TSP). The processes by which trace
organic contaminants are removed from the atmosphere (wet and dry
deposition) and the quantity ultimately deposited on the water/land
surface depend on the distribution between the vapor and particle
phases. Partitioning between the gas and aerosol phase depends on
contaminant vapor pressure, size and surface area of the aerosol,
temperature, and the organic caroon content. The less volatile the
compound, the higher the affinity for TSP. Theoretical considerations
and laooratory and field measurements indicate that PCBs, DDT, Eg, low
molecular weignt (MW) hydrocarbons, and low Mff PAHs exist primarily in
the gas phase in "clean" airsheds, while the more chlorinated PCB
congeners, high Mff PAus and dioxins occur primarily in the particle
phase. In "dirty* wr uruan/industrial airsheds, a greater fraction of
the total atmospheric burden for a particular chemical will occur in
the particle pnase. Particle size plays a significant role in the
removal efficiency of aerosol-bound contaminants. Organic species
tend to concentrate in the snbmicron particle-size fraction (i.e.,
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8
aerosol) and will be primarily removed by precipitation scavenging
(>70 %) while larger particles will have a greater fraction removed by
dry particle deposition.
Wet Deposition
The mechanisms of wet removal from the atmosphere are very
different for particle-associated compounds than for gas phase
compounds. The relative importance of these two processes depends on
the distribution of the organic compound between vapor and aerosol,
particle-size distribution and Henry's Law Constant (H). Non-reactive
organic gases will be scavenged by rain according to H if equilibrium
between the gas and aqueous phases is achieved (2,3). Henry's Law
constant, H, is the ratio of the compound's vapor pressure to its
solubility for low solubility compounds. In the absence of chemical
reactions occurring in the droplet, an atmospheric gas should attain
equilibrium with a falling raindrop in about ten meters of fall. The
position of equilibrium defined by H is a function of temperature as
it increases by about 2 for each 10°C rise in temperature (3).
The total extent of organic compound scavenging by falling
precipitation may be given as:
T g p
where WT = overall scavenging efficiency
W - [rain-T]
T- [air,T]
is the gas scavenging ezficiency
W
[rain, diss]
g ~ [air, gas]
-------
«_ is the particle scavenging efficiency
P [air, part.]
and d is the fraction of the total atmospheric concentration occurring
in the particle phase.
An atmospheric gas attaining equilibrium with a falling raindrop
is scavenged from the atmosphere inversely proportional to H:
Vr-
where R is the universal gas constant, T= temperature, H= Henry's
Law Constant, and a = solubility coefficient. Surface flux then
becomes:
F = o'J'C = W 'J'C
g g g g
where J = rainfall intensity, and C = concentration of organic gas in
the atmosphere. Field determined WT values are generally larger than
W values based on H for some organic compounds suggesting particle
scavenging by precipitation is an important flux term. Ligocki et al.
(3) have reported gas scavenging etficiencies for a variety of
nonpolar organic compounds measured in the field in Portland, OR.
Tables 1 and 2 from their paper compares the field-determined W
values to those estimated from consideration of H and ambient
temperatures. They obtained W values ranging from 3 to 105, and
which were underestimated by factors of 3 to 6 using E data at 25°C.
Correcting published H values for ambient temperatures of 5 to 9°C,
equilibrium between the atmospheric gas and dissolved constituent of
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Table 3. Mean dissolved rain concentrations (ngS~'±ls). mean gas phase concentrations (ngm"J± 1 s), correlations
between rain and air data and gas scavenging ratios
Table 1,
(Ref.3)
Compound
Tetrachloroethene
Trichloroethene
Mesitylene
Toluene
Durcne
1,2,4-Trimeihylbenzene
Ethylbenzene
m + p-Xylene
o-Xylene
1.4-Dichlorobenzene
1,2-Dichlorobenzene
1.14-Tnchlorobenzene
C2-naphthalenes
Naphthalene
2-Methylnaphthalene
1-Methylnaphthalene
Dibenzofuran
Acenaphthene
Fluortne
Acenaphthylene
Anthracene
Methylphenanlhrenes
Dibenzothiophene
Phenanthrene
Benzp[e]pyrene
Pyrene
Fluoranthene
Benzo[b -rj + JL]fluoranthene
9-Fluorenone
Benz[a]amhracene
Chrysene
Diethylphthalate
Dioctylphthalate
9.10-Anthracenedione
a-HCH
Dibutylphthalate
Mean concentrations Correlation
Rain Air (H)
4.6±3.4
5.6 ±5.6
5.1 ±15
88±75(S):
19 ±1.3
30±I4
34 ±21
110±73
45 ±31
4.8+1.2
0.26+0.20(5)
0.25+0.17(3)
17±6
100+32
45 ±16
29+11
17 + 6
5.4 ±10
14+4
37 ±13
5.1 ±10
30+8
41 ±2.1
90±26
0.37+0.20(2)
39+13
48 ±17
1.6+1.9(2)
79 + 21
3.3 ±1.0
79±2.8
59 ±30
2.6 ±08 (6)
67Z26
H±3
46 ±10
I200±690
1500+1300
430+220
3800+2400
120+70
1300±800
1300±700
3400+2000
1300+690
120+32
5.8 ±13
3.8+0.4
91 + 35
450 ±220
200±120
96+54
19 + 5
5.5 ±1.9
9.5 ±14
28+16(4)
18 + 1.0
13 + 3
1.6+0.5
27 + 7
0.03+0.01 (5)
6.8+1.9
7.8+10
0.11+0.14(5)
7.0+ 1.7
0.28+0.07
0.45+0.07
17 r 0.4 (4)
039+0.39(5)
2.5 + 0.8
0.34 + 0.05
0.37(1)
0.97
0.81
0.82
0.97
0.73
0.33
0.75
0.68
0.79
021
0.91
-§
0.87
0.37
0.67
0.78
0.69
0.16
0.16
0.28
0.48
0.09
0.59
036
—
0.09
0.20
—
0.52
0.06
0.00
0.03
—
0.64
0.48
—
Wl (meas)
Vc-
3.6 ±1.1
3.7 ±1.3
12 + 3
22±5(5)
26±9
27 ±9
27±11
33+17
35 ±15
39+10(6)
46+13(5)
66 ±51 (3)
190±32
250±73
250±78
330±100
930+180
1000+310
1500+390
1600 ±500 (4)
1900±600
2500 ±800
2500±900
3400+740
5800(1)
S900± 1800
6300+2000
7400+1300(2)
11,000±2200
12,000+4900
18,000±6500
20.000+11000(4)
20.000 ±20.000 (4)
27,000+7000
31,000+6900
110.000(1)
• (lit)
25"C
1.0
14
4.5
3.7
1.0
4.2
3.7
3.51
4.8
8.2
12
11
661
59
48
56
250
350
72
680
1100
. 2900
2400
1300"
4300
23,000
21,000
4200
87.000
Ref.t
2
2
2
I
2
2
1
2
2
1
1
1
2
2,3
2
2
3,4
3.4
3,4
3.4
3,4
3.4
3.4
1
3.4
1
1
1
1
•A\erage temperature during sampling. +1 = Mabey et al. (1982), 2 = Mackay and Shiu (1981). 3 - Sonnefeld el aL
(1983). 4 = Pearlman et al. (1984). J Number of samples, if other than seven. §Correlation not computed for fewer than
four points ' Average of the values for m-xylene and p-xylene. T Value for 1-ethylnaphthalene. "Average of the values
for benzo[fc]fluoramhene and benzo[L]fluoranthene.
Table 4 Comparison of field Wt values to temperature-ilependem a values* for polycyclic aromatic hydrocarbons
Compound
Naphthalene H',
a
Table 2. ,,ya
Ruorene W,
f r+ e f\ \ S
(Ref.3) n//,,
Phenanthrcnc W,
a
Anthracene W,
a
HVa
Fluoranthene If,
a
U/ /
•/•*
Pyrene If,
a
**y«
Benz[a]anthracene W,
9
w,/«
2/12-2/13
8C
160
190
086
1200
1200
1.0
2900
3600
0.81
1000
2300
0.43
5100
6000
0.85
5000
9800
0.51
11,000
8700
1.3
2/14-2/15
6'C
340
220
1.6
2200
1400
1.6
3400
4300
080
2100
2700
0.78
6000
7100
0.85
6200
11000
0.52
14,000
9800
1.4
Sample date and mean temperature
2/20-2/21 2/23-2/24 2/29-3/1 3/16-3/20
5C 7'C 9C 9C
240
240
10
1500
1500
1.0
3900
4700
0.84
1800
2900
0.60
6900
7600
091
6600
13,000
0.51
21000
10.000
12
290
200
1.5
1300
1300
1.0
4100
3900
1.1
2100
2500
0.84
7000
6500
1.1
7000
11,000
0.64
13.000
9300
1.4
140
170
0.81
930
1100
0.84
2100
3300
0.62
1400
2200
0.63
3500
5600
0.63
3000
8700
0.34
8000
8200
0.98
270
170
1.6
1500
1100
1.4
4000
3300
1.2
2700
2200
1.2
9900
5600
1.8
8600
8700
0.99
9400
8200
1.1
4/1 1-4/12
8"C
290
190
1.5
1500
1200
1.2
3300
3600
091
2000
2300
0.85
5400
6000
0.90
4800
9800
0.49
7300
8700
0.84
Average
1.3
1 1
0.90
0.76
1.0
0.57
1.3
•a values were calculated from the data of May et al. (1978) and Sonnefeld el al (1983).
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10
precipitation was demonstrated for several PAHs. Based on these
results, temperature-corrected W values may be used to estimate
organic gas concentrations in the atmosphere or temperature-specific H
values.
Precipitation scavenging of particles containing sorbed organic
species (W ) permit the calculation of surface fluxes:
WJ'CP
where F is the particle flux and C is the concentration of
P P
atmospheric particnlate organic compound. Depending on particle size,
precipitation intensity and type of meterological event, W may equal
10* to 10 . The higher value implies that the aerosol is readily
incorporated into cloud water and is hygroscopic. The lower value
implies a non hygroscopic, probably carbonaceous particle that is not
readily incorporated into cloud water. Below cloud particle
scavenging efficiencies of 10 to 10 for 0.01 to 1.0 |im particles
have been reported. The most comprehensive study of particle
scavenging by precipitation was conducteu by Ligocki et al. (4).
Tables 3 and 4 list W values of 102 to 105 for a series of PAHs.
P
alkanes and phthalates and compares W to W values. In general, W_
p g p
values were consistent with below-cloud and in-cloud scavenging for
PAHs, in which the compounds with higher scavenging ratios were
associated more frequently with large particles. To adequately
predict W 's, detailed information on particle-size distribution,
organic concentrations in particle-size ranges and meteorological
parameters are needed.
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Table 3. Particle scavenging ratios for neutral organic compounds during rain events in Portland, Oregon in
1984
Table 3.
(Ref.4)
Compound
2/12- 2/14- 2/20- 2/23- 2/29- 3/16- 4/11-
2/13 2/15 2/21 2/24 3/1 3/20 4,12
frontal weak showers cold warm showers cold
MW cyclone storm front front front
Polycyclic aromatic hydrocarbons and derivatives
Dibenzofuran
Fluorene
9-Fluorenone
Phenanthrene + Anthracene
Methylphenanthrenes
Fluoranthene
Pyrene
9,1 0-Anthracenedione
Benz[a]amhracene
Chrysene
7-Benz[de]anthracenone
Benzofb +j + i]fluoramhene
BenzoMpyrcne
Benzo[a]pyrene
Perylene
Benzo[0Jii]perylene
Coronene
Average of PAHs with MW <
Average of PAHs with MW >
Alkanes
168
166
180
178
192
202
202
208
228
228
230
252
252
252
252
276
300
202
202
NA»
NA
29.000
19,000
19,000
4500
2600
1700
640
1700
560
1300
1400
580
630
1300
2000
15.000
1200
4900
NA
NA
2500
NA
2400
1700
NA
410
1100
NA
430
430
180
NA
NA
NA
2900
510
23.000
34.000
NA
38,000
15,000
15.000
13.000
2600
1300
3500
1100
2700
3000
2500
2600
4200
1800
24.000
2500
NA
NA
9000
5600
3400
3500
3600
1400
400
1200
900
3200
2800
1200
920
3900
NA
5000
1800
9300
8200
17.000
17,000
11.000
12,000
10.000
3900
2300
4500
2700
4900
4500
3900
3000
5800
14.000
12.000
5000
5500
2400
1900
15.000
NA
23.000
20.000
NA
2600
3800
NA
2100
1700
NA
NA
NA
NA
11.000
2600
NA
NA
18,000
21000
NA
18.000
14.000
NA
1100
2400
NA
900
290
NA
NA
290
NA
18.000
1000
Eicosane
Heneicosane
Docosane
Tricosane
Tetracosane
Peniacosane
Hexacosane
Average of alkanes
Phthalate esters
Buiylbenzylphthalate
Bis[2-eth>lhexyl]-
phthalate
Dioctylphthalate
Average of phthalates
282
296
310
324
338
352
366
298
391
391
21.000
14.000
15.000
27.000
10,000
47.000
NA
21000
1000
9100
29,000
13.000
NA
NA
NA
3900
NA
5000
3300
4100
NA
NA
NA
NA
15.000
16.000
11000
16.000
18.000
11.000
14.000
15.000
13.000
37.000
15.000
21000
89.000
76.000
63.000
29.000
NA
26.000
NA
57,000
10.000
15.000
65.000
30.000
44.000
46.000
34,000
44.000
27.000
29,000
36,000
37,000
NA
NA
NA
NA
NA
10.000
NA
NA
NA
NA
NA
10.000
NA
NA
35.000
35,000
31000
12.000
6300
13.000
6400
21000
7000
14,000
NA
NA
25,000
25.000
Table 4.
(Ref.4)
Table 4 Mean particle scavenging ratios, mean gas scavenging ratios*, and overall scavenging ratios for
neutral organic compounds
Compound
Mean«t Mean Wf Mean
Dominant
Mean W* scav. mech.§
a-HCH
Diethylphthalale
Dibenzofuran
Fluorene
Phenanthrene + Anthracene
9-Fluorenone
Methylphenanthrenes
Fluoranthene
Pyrene
Eicosane
9, 10-Anihracenedione
Heneicosane
Dioctylphihalate
Docosane
Chrysene
Benz[a]anthraccne
Benzo[e]pyrene
Bcnzo[a]pyrene
Benzo[b +j + L]fluoramhene
Perylene
Tricosane
Tetracosane
Peniacosane
Hexacosane
Bis[2-eth> lhex> l]phthalate
Benzo[g)ii]peryiene
Coronene
0.0
0.0
0.008
0.009
0.011
0.021
0.027
0053
0.071
0.14
0.21
0.41
0.56
0.61
0.71
075
0.97
098
098
1.0
1.0
1.0
1.0
10
1.0
1.0
1.0
NA«
NA
11.000
15,000
17,000
15.000
13,000
11,000
9300
40,000
2400
31000
36.000
27.000
2600
1300
2000
1700
2200
1800
21000
16.000
23,000
15.000
20.000
3100
5900
31,000
20,000
930
1500
3300
11.000
2500
6300
5900
NA
27,000
NA
20,000
NA
18,000
11000
5800
NA
7400
NA
NA
NA
NA
NA
NA
NA
NA
31.000 j
20.000 i
1000
1600
3500
11.000
2800
6600
6100
5600
21000
13.000
30.000
17.000
7000
4000
2100
1700
2300
1800
21000
16,000
23.000
15,000
20,000
3100
5900
•Mean gas scavenging ratios from Ligocki ei al. (1985). t$ = [aerosol]/[vapor + aerosol]. J»P
= H p$ + irf (I -0). §g a gas; p = panicle. iNA = not available
-------
11
The total wet surface flux of organic compounds in the atmosphere
may be estimated from:
FT= VCair= V
Drv Particle Deposition
The dry deposition of particle-bound organic compounds onto a
receptor surface depends on the type of surface, resistance to mass
transfer in the deposition layer* particle size, and macro- and
micrometeorology. Particles are delivered to surfaces by Brownian
diffusion (mmd < 0.3 |im) , inertial impaction-interception (nmd = 0.5-5
|im) and gravitational settling (mmd > 5 urn). Because Brownian
diffusion increases below 0.3 urn and inertial impaction-interception
increases as particle size increase above 0.5 |im, the minimum
deposition velocity (Vd) is in the range of 0.3 to 0.5 urn. As stated
earlier, nonpolar organic compounds in the atmosphere tend to
concentrate on the small, caroon-rich, high surface area particles.
In the simplified case, the flux of particles to a receptor
surface i.:
v, dry d p
where F . is the surface flux of particle-bound chemical, Vd is the
deposition velocity and C is the organic concentration in the
particulate phase. The particle deposition velocity, V^. may be
viewed as the result of a series of resistances in transfer from the
well-mixed atmosphere to the surface (Figure 1) .
-------
Figure 1. Simplified Model of Dry Deposition
(from M. Weseley, ANL)
v , deposition velocity
d
- -F/C
- l/(r + r + r )
a b c
?r
C = concentration at height z
r , aerodynamic resistance
a
rb« sublayer resistance
/ / / / C , surface concentration
s
C , subsurface resistance
ss
ass umed zero
All resistances are for conceptual
horizontal lavers.
-------
12
where r t T are aerodynamic, sublayer and subsurface resistances,
a D c
respectively and C is the particnlate concentration at a reference
PI Z
height. If r is assumed to be zero, then the aerodynamic resistance
components r , r. may be roughly estimated from local measurements of
u , mean wind speea at a specified height! and o.g, a measure of
atmospheric stability. V. (l/(r + r.) estimates for the Great Lakes
based on seasonal atmospheric stabilities varied with season with
values of 0.5 to 1.0 cm/sec in summer to 1.7 cm/sec in the colder
months. H. Wesley (Argonne) and A. Andren (University of Wisconsin)
point out that the following measurements or data are essential to
adequately predict (Jmoue^") dry particle deposition:
C(r); concentration as a function of particle size;
u(z); wind velocity at a reference height;
T -TA; surface and atmospheric temperatures;
S A
IL; relative humidity;
11
p(r); particle density as a function of particle size;
D(r); molecular diffusivity as a function of particle size;
OC(TSP); organic caroon content;
TSP; total suspended particulate concentrations.
These parameters may be used in a variety of dry deposition models
(5,6) to quantify particle deposition.
Particle deposition velocities have been estimated from
deposition to artificial surfaces (grass! trees; filter paper; glass
or Al plates; plates coated with hydrophilic substances such as
-------
13
ethylene glycol). For a number of nonpolar chlorinated hydrocarbons
thought to associate with fine particles, V. values of 0.1 to 1.0
cm/sec were observed. These values are similar to estimates for
reactive gas and aerosol deposition to soils, grass, trees,
agricultural crops and snow.
A. Andren suggested that measurements required to assess dry
deposition needed to occur on an event basis during unstable
atmospheric periods and also on a regular periodic basis. This
assumes that particle deposition tends to concentrate during intense,
episodic periods; however, field measurements are few. Measurements
should be performed in a few rural areas representative of "regional*
deposition and more intensively in major source areas. It is always
preferable to make the measurements over the lake than on the
shoreline. Atmospheric organic contaminants should be measured with
both high volume and low volume samples. It is advisaole to determine
particle size distributions as well as a measure of total C and TSP.
Dennders may be of some vaine in isolated situations. These sampling
procedures are severely restricted by analytical detection limits.
T. Murphy (DePaul University) has suggested that although most of
the atmospheric burden of nonpolar organic compounds may be in the gas
phase, and these contaminants are concentrated on fine particles, dry
deposition especially near sources, may be dominated by large particle
deposition. Gravitational settling velocities for large particles are
greater than 2 cm/sec while snbmicron-sized particles may have
deposition velocities much less than 1 cm/sec. Urban and industrial
centers bordering the Great Lakes may contrionte to regional emissions
-------
14
and deposition as well as intense localizvd deposition (e.g., Chicago,
H, - Gary. IN ; Detroit, III; Hamilton, Ont.).
The relative importance on wet versus dry deposition (R) depends
on the proportion of atmospneric organic concentration in the gas and
particle phases ((ft), and the relative efficiency with which each phase
is removed by wet and dry deposition. In general,
[
-------
Table 5. (from A.W. Andren)
TOTAL ATMOSPHERIC FLUXES AT CRYSTAL LAKE
ELEMENT
AL
PB
PB-210
WET1
3,
0,
1,
6
8
58
6
0
DRY2
,9(66)
,2(20)
TOTAL SED, RATE
3
3
0, 21(12) 3
10,
1,
1,
5
0
79
11,
1,
1,
1
24
86
UNITS
/
JUG - CM"'
t
nr - rw~'
^JG CM
t
DPM - CM"'
!- YR-1
•- YR-1
'•- YR-1
ON RAIN DEPOSITION ONLY.
UNCERTAINTY is ABOUT ± 20% (TALBOT, 1981)
3INDICATES % DRY INPUT,
4EDGINGTON AND ROBBINS (1976) ESTIMATE 1,5 FOR LAKE MICHIGAN
(STA, 17),
-------
15
Fo
KoL *L ffig
where F = flux in moles/nr * hr; K, ,K = liquid and gas-phase mass
transter coefficients (m/hr); C= solute concentration in liquid phase
(moles/m3), P= solute partial pressure in atm.; T= absolute
temperature in °K, and R = gas constant. The volatilization rate may
be controlled by resistance to mass transier in the liquid phase, gas
phase or a combination of the two. At typical values of K, and K (20
cm/hi and 2000 cm/hr, respectively), resistance to mass transfer
occurs > 95% in liquid phase for H 1 4.4 x 10~3 atm m3/mole, and > 95%
in gas phase for H i 1.4 x 10~' atm nr/mole. Considering the range ot
H values for PCB congeners, 60 to 90% of the resistance occurs in the
liquid phase at 25-C. This implies that, in general, slightly soluble
PCBs with H > 10"* atm a?/mole tend to volatilize from water; however
transfer direction is established by the concentration gradient.
Examples of compounds where this occurs are PCBs, many CHs including
pesticides, chlorinated benzenes and tetrauhloroethylene.
Theoretical and experimental methods to estimate mass transfer
coefficients in the field for gas and liquid-phase controlled organic
compounds have been developed. Mackay and Yeun (8) have suggested
equations relating environmental mass transfer coefficients based on
Schmidt number (Sc) and windspeeu at a reference height of 10 m (Ri/\:
m/sec):
K = 1.0 x 10~3 +46.2 x 10~3 D* Sc ~°-67
-------
-3.0
-3.5
log Hor H'
(atm m3\
mole /
-4.0
-4.5
-5.0
— * Hfield
O L. Superior
— H,Qb(51)
- H (at 10° and 25°C)(27)
- • •
0 ° « o B 8
o t g
- o
1 1 1 1 1 1 1 1 1 A
/Mean values for
' 3 to 5 Cl-substituted
biphenyls (51)
•
0
o
o
I I I I
8 16 18 20 28 49 52 70 74 87 91 97 101 118
PCB Congener Number
Figure 2. Henry's Law Constants (H) and Air-Water Partition
Coefficients (H') for PCB Congeners Measured
in Air (vapor) and Water (filtrate) in Lake
Superior- 1980 (Ref. 13).
> H(25°C)
H(10°C)
-------
16
1.0 x 10~6 + 34.1 x NT4 U* Sc^0-5 (D* > 0.3)
1.0 x 10~6 + 144 x 10~4 D*2-2 Sc0-5 (U* < 0.3)
U*1(euv) =6.1 +0.63 U^)0-5 UIQ
where D = air-side, friction velocity (m/sec). Results suggest that
environmental mass transfer coefficients will generally be lower than
those measured in the laboratory. Annual integrated K, values for
liquid-phase controlled organic compounds determined from mass balance
calculations on large lake systems are 0.2 to 0.25 m/day, or about 50
to 100% smaller than predicted from laboratory experiments: (Table
6).
Table 6. K, Values Determined from Mass Balance Calculations
Lake Compound ]L (m/day)
Zurich 1,4-dichlorobenzene 0.24
Saginaw Bay, PCBs 0.2
Lake Huron
Lake Superior PCBs 0.24
Great Lakes PCBs 0.10
(modified from Ref. 13)
Estimating volatilization of PCBs, for example, is complicated by
the inability to accurately determine the concentration of the
dissolved, unassociated species in equilibrium with the atmospheric
vapor. An example of this phenomenon is presented in Figure 2, where
Henry's Law Constant (H) or air-water partition coefficients (H') for
several PCB congeners are compared to apparent air-water partition
coefficients (H') determined from measurements of atmospheric PCBs in
-------
17
the vapor phase and dissolved PCus in two surface water samples from
Lake Superior (13).
The apparent H' values are lower than the range ox H values for
the 3 to 5 substituted PCS congeners at 25°C but similar to H values
at 10°C, much closer to the ambient temperature of Lake Superior. The
temperature dependence on H for PCt>s (9) suggests that gas-phase PCBs
may be absorbed into the lake at colder temperatures and lost via
volatilization at warmer temperatures. For bodies of water such as
Lake Superior, PQ*S absorption may be important for 9 or 10 months
of the year.
Air—Transfer Scenario! PCBs as an Example
Figure 3 depicts our present understanding of the relative
importance of air-water transfer processes for hydrophobic organic
cycling in large lakes. The dominant input pathway is the scavenging
of particles from the atmosphere containing sorbed organic species,
with dry particle deposition being much less important. Particles
thus reaching the lake equilibrate with the new aqueous environment,
and partition between the dissolved phase and other biotic and abiotic
particle phases. PCBs in the dissolved phase equilbrate with the
atmospheric gas phase or or mixed downward. Several important
observations can be made. The major input is through precipitation
scavenging of particles and the major losses are through
volatilization and sedimentation. It is conceivable that measurement
of PCS flux to the atmosphere via volatilization may be more than
counterbalanced by atmospheric inputs on particles. Hackay and
Paterson (9) describe this phenomenon as a dynamic, steady-state but
-------
WET
DEPOSITION
DRY
DEPOSITION
VAPOR
VAPOR A
EXCHANGE
res
t
PARTICLE
AIR
^
WATER
SEDIMENT
D= Dissolved-phase concentrations
P= Particle-phase concentrations
Figure 3. PCB Air-Water Transfer Scenario (Ref. 13)
-------
18
non-equilibrium process whereby the input (particle scavenging) is
connected to loss (volatilization) by the equilbrium partitioning of
hydrophobia species. This model also suggests that airborne
concentrations of organic contaminants over the lakes are partially or
wholly derived from in-lake processes. Compounds such as PCBs may
cycle between water and air with intermittent periods of intense
deposition followed by slower but prolonged volatilization.
4.0 Great Lakes Atmospheric Deposition (GLAD) Network
T. Murphy (DePaul University; thoroughly reviewed the present
GLAD network as to whether it fulfilled its overall mission to
quantify atmospheric inputs of nutrients, metals and toxic organic
contaminants to the Great Lakes. He concluded that the GLAD network
as presently constituted is not adequate to provide needed data on
atmospheric loading rates of trace metals and toxic chemicals. This
conclusion was basea on evaluation of GLAD using criterea based on
siting, sample collection methodology and solute analysis. Figure 4
shows the locations of the 36 stations comprising the GLAD network and
15 stations on the Canadian side. Each GLAD site is equipped with
weejcly-integrating, wet/dry automatic precipitation samplers. Until
recently, 28 sites had been equipped with three bulk colectors. The
bulk collectors have now been discontinued such that the 36 sites
collect integrating wet-only precipitation samples for nutrient and
trace metal analysis. There is presently no sampler dedicated to
-------
19
organic monitoring studies. Murphy applied a set of criterea
developed by EPA to sites listed in Table 7. Siting criterea relate
to obstructions nearby, distance between samplers, orientation of
samplers, nature of ground cover, use of rain gauges and distance to
nearest local contaminating sources such as roads, etc. More than 50
% of the sites are located in areas directly impacted by
urban/industrial sources; most are within 0.5 km of the shoreline and
many are located on roofs. A few sites are located on islands in the
lakes, but none collect samples on or over the lake.
D. Gatz (Illinois Water Survey) examined the chemical data
collected at GLAD sites in 1982 and compared them to data similarly
collected at regional National Atmospheric Deposition Program (NADP)
and National Trend Network iNTN) sites. The NADP sites shown in Figure
5 are located away from the lakes and localized sources, and may be
considered representative ot regional deposition. GLAD sites are more
closely aligned with urban areas and lake shorelines. A comparison of
ion balances for 11 NADP sites and 36 GLAD sites for 1982
precipitation show the GLAD data routinely exhibit cation deficits
(Figure 6). This behavior suggests problemns in quality assurance and
control at the analytical laboratory.
Spatial distributions portrayed using median concentration
isopleths for sulphate, nitrate, pH, ammonium and calcium showed close
agreement between NADP concentrations and NADP + GLAD concentrations
in similar areas. The GLAD sites added spatial resolution and
coverage in urban areas. Cumulative frequency distributions for the
same ions at pairea sites in GLAD and NADP consistently showed
-------
Figure 5. NADP/GLAD Site Map A — NADP
(D. Gatz, III. State Water Survey) p, QLAD
-------
6
llJ
O
u
u
or
Ld
CL
COMPARISON OF ION BALANCES, 1982
4O
35 -
30 -
25 -
20 -
1 1 NADP SITES AND 37 GLAD SITES
15 -
10 -
-100 -SO -6O -4O -2O
O
2O
1OO*(SUM A - SUM C)/(SUM A -t- SUM C)
NADP (448 Sa) A GLAD (367 Sa)
1OO
Figure 6. Comparison of Ion Balances, 1982 in the
GLAD/NADP Networks
(D. Gatz, III. State Water Survey)
-------
WET COLLECTOR SITES
X -
D =
LAKE SUPERIOR
QQ
Figure 4. Wet Collector Sites in U.S. GLAD and Canadian Networks.
-------
20
differences between the site populations (Figure 7) for sulphate and
calcium median concentrations. These data show that major element
concentrations and deposition generated in the NADP network adequately
describe regional inputs. GLAD sites may more properly
describle urban inputs.
0. Gatz concluded that GLAD network laboratory measurements of pH
are biased low, major ion concentrations are similar but generally
higher that NADP/NTN values, and wet deposition demonstrates the
influence of local urban loading effects. The GLAD network adds
resolution to the other network sites located in the Great Lakes
vicinity.
5.0 Recommendations for a Great Lakes Atmospheric Inputs and Sources
(GLAIS) Network.
5.1 General Recommendations
The most important recommendation is that the relevant U.S. and
Canadian agencies cooperate in the formation of an "Integrated
Atmospheric Deposition Network". The relative importance of the
atmospheric deposition pathway compared to other input pathways is a
matter of conjecture. In the Upper Lakes, especially Lake Superior,
inputs of PCBs, DDT, JfAHs, and chlorinated diozins and fuxans are
derived primarily from atmospheric deposition (7, 11-13). In the
Lower Lakes, atmospheric inputs may dominate for some compounds but
riverine sources dominate in most cases. For example, atmospheric Pb
input to Lake Michigan is accounted for by accumulation in bottom
sediments. In contrast, PCBs are about equally loaded from
-------
Table 7A. Compliance of GLAD Sites to Criteria
Key to Column Headings In Table
(from T. Murphy, DePaul University)
Rf = Are collectors on a roof?
Rg * Does the site have a recording rain gauge?
Sp • Is the site located at a Waste Water Treatment Plant (POTW)?
Tr • Are trees obstructing the site (angle >45* above horizon)?
Rd - Is there a frequently used road within 100m of the site?
Co - Are the collectors located too close to one another?
So « Is a local source adversly affecting the site?
Ob • Are objects obstructing the site (angle >45* above horizon)?
Siting criteria from EPA Quality Assurance Manual for
Precipitation Measurement Systems (1985).
\ - Obstructions subtend an angle less than 30* with the horizon.
2 = The distance between samplers or rain gages is >2m.
3 « Routine air, ground or water traffic is more than 100m distant.
4 = There are no overhead wires that affect the collectors.
5 = Open storage of agricultural products, fuels or other foreign materials
are not be within 100m of the collectors.
6 = The ground surface is grass or gravel, and is firm.
7 = wet/dry collectors are oriented parallel to the prevailing winds with
the wet bucket upwind.
8 - The rain gage is oriented parallel both to the collector and to the
prevailing wind
Cl = Station Classification
Class I: Station satisfies criteria 1-8;
Instrumentation Includes: automatic precipitation collector
recording rain gauge; pH and Cond. meters; Wind speed and dir
sensors; 502 and NOX analyzers.
Class II: Station satisfies criteria 1-8;
Instrumentation includes: automatic precipitation collector
recording rain gauge; pM and Cond. meters.
Class III: Station satisfies criteria 1-8;
Instrumentation Includes: automatic precipitation collector
non-recording rain gauge; pH and Cond. meters.
Class IV: Station does not satisfy all 8 criteria;
Instrumentation Identical to Class I station.
Class V: Station does not satisfy all 8 criteria;
instrumentation identical to Class n station.
-------
5ft GLtt
Table..7B; Compliance of GLAD Sites to Criteria
(from T. Murphy, DePaul University)
Name Hi RG SP Tr Rd Co So Ob 1 2 3 4 5 6 7 8
C1
288a
?a
Da
291 a
3a
«.,5a
7a
8a
299a
la
2a
303a
"4a
5a
307a
8a
9a
310a
" la
a
jj ja
°'4a
5a
_.6a
3l7a
8a
9a
320a
-"•la
'2a
j^!3a
•5?4a
!5a
lO
502
I3
14
308
OP
QQ
QR
AQ
QU
QT
QG
uV
QL
QJ
DQ
QU
QF
BQ
CQ
QZ
QD
QB
RQ
QA
PQ
KO-
TO
LQ
MQ
NO
JO
IQ
HO
GO
FQ
SO
QE
QM
ON
00
COM
CON
CON
CON
Evanston
Jardine Plant
So. Water Plant
Bay City
Beaver Island
Benton Harbor
Eagle Harbor
Emp i re
Escanaba
Grand Mara is
Mt. Clemens
Muskegon
Ontonagon
Port Austin
Port San i lac
Tawas Point
Duluth
Gooseberry Fls
Gull Lake
Houland
Cape Vincent
Silver Creek
Sodus Point
Grand Island
Olcott
Rochester
Conneaut
Fairport Harbor
Lorain
Put-In-Bay
Toledo
Erie
Cornucopia
Green Bay
Mam towoc
Milwaukee
Hammond Bay
Rossport
Uawa
Sault Ste Mane
Sarnia
Y
Y
Y
Y
N
Y
N
N
Y
N
Y
Y
N
Y
N
N
Y
N
N
N
N
N
N
N
Y
Y
Y
Y
Y
N
N
Y
N
N
Y
Y
N
N
N
N
N
y
y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
N
Y
N
N
N
N
N
N
y
N
N
Y
N
Y
Y
N
Y
Y
N
N
Y
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
Y
N
Y
Y
Y
N
N
N
N
Y
N
N
N
N
N
N
N
N
N
N
N
N
N
Y
N
N
N
N
N
Y
N
Y
Y
N
N
Y
N
Y
Y
N
N
Y
N
N
N
Y
Y
N
N
N
N
N
N
N
N
N
N
Y
N
N
Y
N
Y
Y
N
N
Y
Y
N
Y
N
N
N
N
Y
Y
Y
N
Y
N
N
N
N
Y
Y
N
N
N
Y
Y
N
Y
Y
Y
Y
Y
N
Y
Y
N
Y
N
Y
Y
N
Y
Y
Y
Y
N
Y
N
N
Y
N
N
N
Y
N
N
Y
Y
N
N
N
N
N
N
N
N
N
N
N
N
N
Y
N
N
N
Y
N
N
N
N
N
N
N
N
N
N
Y
Y
Y
N
N
N
N
Y
N
N
N
N
N
N
N
N
Y
?
N
N
N
N
N
Y
Y
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
Y
Y
N
Y
Y
N
Y
Y
N
Y
N
N
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
Y
Y
N
Y
N
N
N
N
Y
N
N
Y
Y
Y
N
Y
Y
N
N
Y
Y
N
Y
Y
N
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
Y
N
N
Y
Y
N
N
Y
N
Y
Y
Y
Y
N
N
N
Y
N
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
r
Y
N
N
N
N
Y
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
Y
Y
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
y
Y
N
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
Y
Y
Y
N
Y
Y
Y
Y
Y
N
N
N
Y
Y
N
Y
Y
Y
Y
N
"
MA 1 1
I^H J 1
MA 1 T
ran l i
Y V.
Y II
Y ! 1
T i *
N V
Y y
N y
N y
Y y
Y y
N y
Y y
N y
N y
N V
NA
NA
N U
NA
NA
NA
NA
NA
NA
N V
NA
NA
Y y
NA
N y
Y II
NA
Y 11
Y I
NH
NA
NA
Y y
NA
CDN Niagara ot Lake N N N Y
N
N
NNYYYYYNA
C-3
-------
UJ
D
C)
UJ
UJ
O
tti
UJ
0.
CUMULATIVE FREQUENCY DISTRIBUTION
SULFATE. 1982
1OO
90 -
30 -
70
60
5O
40
3O
20 -
1O -
O -
A
GLAD SITE QV
—i— —r~ ~r~
4 6
SULFATE CONG (mg/L)
n NADP 3ITE Ml—Otl
s
Figure 7. Cumulative Frequency Distributions for
GLAD and NADP Networks:
A. Sulfate; B. Calcium
(D. Gatz, III. State Water Survey)
-------
_
LJ
O
UJ
O
LI
CUMULATIVE FREQUENCY DISTRIBUTION
100
O
CALCIUM, 1982
O
D GLAD SITE QV
CALCIUM CONC (mg/L)
A NADP SITE MI-O3
-------
21
atmospheric and riverine sources (12). The chlorinated hydrocarbon
burden of Lake Ontario and Lake Erie sediments can only be explained
by dominating inputs from the Niagara River and Detroit River,
respectively. Urban and industrial centers bordering the Great Lakes
may also support intense, localized atmospheric inputs to the
nearshore area ( 30 km) of unknown magnitude. Thus, atmospheric
deposition of organic contaminants to the Great Lakes is impacted by
regional deposition of pollutants transported some distance from their
source, and localized deposition of pollutants transported short
distances from sources. To complicate the issue, regional deposition
is impacted by both regional sources and sources outside of the Great
Lakes Basin. The GLAIS network must take into account these differing
deposition patterns.
The processes controlling atmospheric inputs of specific organic
contaminants are wet depositon (scavenging of gases and particles by
rain and snow), dry particle deposition and vapor-exchange at the air-
water interface. The relative importance of each process depends on
the distribution of the chemical between the gas and particle phase
and the efficiency of removal for each phase. In general, chemical-
physical properties of the organic contaminant (e.g., H; Sol; Pv; Kow)
may be combined with mass transfer parameters (J; Uz', Vd; RH) and
atmospheric concentrations to estimate deposition using simple (rain)
or complex (particle or gas dry deposition) models. The GLAIS network
should include the measurement of these parameters if it is to be
successful.
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22
The organic contaminants which have been frequently measured in
the Great Lakes ecosystem include the PCBs, chlorinated pesticides and
chlorinated compounds whicft are by-products of industrial activities
(e.g., HCB; octochlorostyrene). In addition, some measurements of
PAHs and chlorinated diozins and furans have been reported (R.Bites,
Indiana University, personal comm.). The new GLAIS network should
monitor a suite of frequently encountered toxic chemicals as well as
search for new chemicals introduced into the environment, especially
via emerging technologies such as municipal waste incineration.
The new GLAIS network must incorporate a rigorous sampling
protocol and QA/QC program to ensure the validity of the data. This
protocol must descrioe the development status for each contaminant to
be considered in terms of its concentration, precision, accuracy and
validity (i.e., compliance with assumptions made in analytical
methodology). Care should be taken to provide analytical detection
limits corresponding to expected concentrations. U.S. and Canadian
efforts should be closely coordinated in terms of goals, and sampling
and analytical protocols.
As conceptualized by the workshop participants, the GLAIS network
would encompass about 6 to 8 sampling sites per lake for "routine"
deposition monitoring (2 to 4 in U.S. and Canada each), and 1 or 2
•master* stations per lake which incorporate research and cooperative
studies (1 in Canada; 1 in U.S.). The sites should be evenly
distributed between U.S. and Canadian territory (except for Lake
Michigan). Perhaps 4 of the 8 routine stations should be located to
assess regional inputs and the remaining 4 to assess more localized
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23
urban inputs. The sites should be located, where posssible, on in-
t
lake islands ( e.g.. Beaver Island; Isle Roy ale) and upwind and
downwind relative to the prevailing wind direction. Every effort
should be made to incorporate over-lake sampling and a strong research
component to the new networ*. The routine stations would be equipped
with sufficient wet samplers, air particle samplers and equipment
necessary to collect meteorological data required for modeling
atmospheric deposition.
Alternate methods of estimating total and atmospheric inputs of
organic contaminants to the lakes should be continued. These include
snow-coring, where possible, to obtain integrated winter loading
rates, obtaining dated lace sediment and peat cores and mass balance
studies.
5.2 Specific Recommendations.
5.2.1 Sampling Sites
* Routine Monitoring Sites
* 6 to 8 per lake (divided between U.S. and Canada)
* 3 to 4 per lake in dominant urban areas
* 4 to 5 in rural areas differing in land-use
* In-lake islands and on-lake sites are
preferable to shoreline sites.
* Master Sites
* 1 or 2 per lake (divided between U.S. and Canada)
* Rural and urban area(s)
* Co-located with Canadian sites.
5.2.2 Measurement at Routine Monitoring Sites
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* Wet Deposition
* (1) Wet-only integrating samplers
* 2 week sampling period
* In-situ separation of particulate and idssolved
organic species
* In-situ isolation of dissolved species
* Collector surface area > 0.2 m2
* Samplers suitable for all-weather operation
* Dry Deposition
* (2) Hi-Volume air samplers equipped with filter
and backup adsorbent operated directionally.
* Sampling frequency of 24 hours every 3 days
* (1) Low-volume cascade impactor
* Climatological/Meteorological Parameters
* Continuous recording of rain intensity, temperature,
wind direction and velocity, and relative humidity.
5.2.3 Measurement at Master Sites
* Wet Deposition
* (2) Wet-only integrating precipitating samplers
* (1) Event precipitation sampler
* In-situ separation of particulate and dissolved
species
* In situ isolation of dissolved species
* Collector surface area > 0.2 m2
* All-weather operation
* Dry Deposition
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25
* (3) Hi-volume ait samplers equipped with filter and
backup adsorbent
* Sampling frequency - every 24 hours
* Hi-Vols operated in concurrence with wind vectors
(directional sampling)
* (1) Low flow cascade impactor with backup adsorbent
* (1) Hi-Vol dedicated to TSP and OC measurement
* Climatological/Meteorological Parameters
* Same as for routine monitoring sites
* Meteorological tower for measurement of atmospheric
gradients (e.g., Tsurface - Tair; etc.).
5.2.4 Chemical Measurements
* Routine
* PCBs (total; congeners)
* Chlorinated pesticides and other common QICs.
* PAHs
* Pb, Cd
* Resarch Component (Master Site)
* Tozaphene
* Chlorinated dio&ins and furans
* Hg
* Other
* TSP; OC (TSP); density and mmd of size-differentiated
particles.
5.2.5 Quality Control/Quality Assurance
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26
sampling protocols
loalytical protocols
>lers at U.S. and Canadian sites
sample replication; exchange between
joratories.
inalytical detection limits.
itinning) Deposition Methods
Itudies
>r vinter burdens
in peat cores (atmosphere only)
I/or remote island studies
iation
mpling
ds of specific sources
lysis
onment
earch Component to Monitoring Study
tmospheric inputs of organic contaminants
at the air-water interface may result in
rganic gases or volatilization of organic
Research needs are:
astants (h) for organic contaminants
pendence of H
dodology to distinguisH vapor and
ecies in the atmosphere, and dissolved
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27
and non-dissolved species in the water
* Development/implementation of time-dependent model
describing air-water interactions
* Methodology to estimate environment-dependent mass
transfer coefficients
5.3.2 Detailed study to establish importance of urban vs. nonb-
point. intensive, localized deposition
5.3.3 Development/implementation of of dry particle deposition
models
5.3.4 Development/implementation of field measurements over lake
and at the master site describing dry particle deposition
models.
5.3.5 Identification of non-routine chemical substances in
atmospheric deposition offering potentially adverse
impacts on ecosystem health.
5.3.6 Implementation of research to "calibrate" dry particle
deposition to artificial surfaces.
5.3.7 Conduct research to quantify the relative importance
of atmospheric versus riverine contaminant inputs.
5.3.8 A major field experiment should be conducted in the summer
and winter of 1988 to integrate atmospheric data generated
at the rural and urban master sites with those generated
concurrently from an intensive over-lake study involving a
meteorological tower and surface ship. The objectives of
the multi-investigator study axe to quantify the absolute
atmospheric inputs, the relative importance of the various
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28
input processes, reconcile sources,and to verify
atmospheric deposition models. IVo potential locations
are southern Lake Michigan near Chicago and western
Ontario near Toronto.
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29
REFERENCES
1. U.S. Environmental protection Agency, "Five Year Program Strategy
for Great Lakes National Program Otfice, 1986-1990*. EPA-905/9-85-002:
Chicago, IL; p. 41-45, 1985.
2. SI inn, W.G.N.; Basse, L. J Hicks, B.B.; Hogan, A.W.; Lai, D.; Liss,
P.S.; Hunnich. E.G.; Sehmel, G.A.; Vittori, 0. Some aspects of the
transfer of atmospheric tarce constituents past the air-sea interface.
Atmos. Environ. 19'/8, ±2, 2055-2087.
3. Ligocki, H.P.; Leuenberger, c.; Pankow, J.F. Trace organic
compounds in rain - II. Gas scavenging of neutral organic compounds.
Atmos. Environ., 1985, 19. 1609-1617.
4. Ligocki, M.P.; Leuenberger, C.; Pankow, J.F. Trace organic
compounds in rain - III. Particle scavenging of neutral organic
compounds. Atmos. Environ.,1985, 19. 1619-1626.
5. Andren, A.W. "Processes determining the flux of PCBs across the
air/water interfaces'*, in Physical Behavior of PCBs in the Grea Lakes.
D. Maokay, S. Paterson. S.J. Eisenreich, M. Simmons (Eds.).
Ann Arbor Science Publishers: Ann Arbor, HI. 127-140.
6. Hackay, D.; Yuen, T.K., "Transfer rates of gaseous polltutants
between the atmosphere and natural waters", in Atmospheric Pollutants
in Natural Waters. S.J. Eisenreich (Ed.), Ann Arbor Science
Publishers: Ann Arbor, MI, p. 55-65.
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30
7. Eisenreich, S.J.; Looney, B.B.; Thornton, J.D., Airborne organic
contaminants in the Great lakes ecosystem. Environ. Sci. Tech. 1981,
11, 30-36.
8. Hackay, D.; Yuen,A.T.K.. Environ. Sci. Tech., 1983, H, 211.
9. Burkhard, L.P.: Armstrong. D.E.; Andren, A.W., Environ. Sci. Tech.
1985, 1£, 590-96.
10. Hackay, D.; Paterson, S. A model describing the rates of transfer
processes of organic chemicals between atmosphere and water.
submitted to Environ. Sci. Tech., 1985.
11. Cznczwa, J.H.; HcVeety, B.D.; Hites, R.A., Science, 1984. 226.
568-6*.
12. Swackhamer, D.L. Ph.D. Thesis, University of Wisconsin, Madison,
1985, 258 p.
13. Eisenreich, S.J., The Chemical Limnology of Hydrophobic Organic
Compounds: PCBs in Lake Superior, In Chemistry of Aquatic Pollutants.
R.A. Hites and S.J. Kisenreich, Eds., Advances in Chemistry Series,
American Chemical Society: Washington. D.C., 1987.
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"ATMOSPHERIC DEPOSITION WORKSHOP"
November 20-21, 1985
University of Minnesota, Minneapolis
Names and Addresses of Participants:
Steven J. Eisenreich, Workshop Chair
Environmental Engineering Program
Department of Civil and Mineral Engineering
122 CivMinEng Bldg.
University of Minnesota
Minneapolis, MN 55455
(612) 625-3082
Thomas J. Murphy
Department of Chemistry
DePaul University
25 E. Jackson Blvd.
Chicago, IL 60604
(312) 321-8191
Anders W. Andren
Water Chemistry Program
University of Wisconsin
660 N. Park St.
Madison, WI 53706
(608) 262-2470
James Pankow
Department of Chemical, Biological and Environmental Sciences
Environmental Science Program
Oregon Graduate Center
Beaverton, OR 97006
(503) 645-2111
William Strachan
National Water Research Institute
Canada Centre for Inland Waters
P.O. Box 5050
Burlington Ontario L7R 4A6
CANADA
Donald Mackay
Department of Chemical Engineering and Applied Chemistry
University of Toronto
Toronto, Ontario M5S 1A4
CANADA
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Terry Bidleman
Department of Chenmistry
University of South Carolina
Columbia, SC 29208
(803) 777-4239
Donald Gatz
Atmospheric Chemistry Section
Illinois State Water Survey Division
2204 Griffith Drive
Champaign, 1L 61820
(217) 333-2210
Ronald A. Hites
School of Public and Environmental Affairs
400 E. Seventh St.
Indiana University
Bloomington, IN 47405
(812) 335-3277
Marvin L. Weseley
Atmospheric Physics Division
Building 181
Argonne National Laboratory
9700 S. Cass Ave.
Argonne, IL 60439
(312) 972-5827
Peter Wise, Director
Great Lakes National Program Office (GLNPO)
U.S. Environmental Protection Agency
536 S. Clark St.
Chicago, IL 60605
Ed Klappenbach
GLNPO
U.S. Environmental Protection Agency
536 S. Clark St.
Chicago, IL 60605
(312) 353-1378
Tim Method
Air Management Division
U.S. Environmental Protection Agency
230 S. Dearborn
Chicago, IL 60605
(312) 886-6065
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Eva Voldner
Atmospheric Environment Service
Environment Canada
4905 Duflerin St.
Downsview, Ontario M3H 5T4
(416) 667-4788
C.H. Chan
Canada Centre for Inland Waters
P.O. Box 5050
Burlington, Ontario L7R 4A6
CANADA
(416) 637-4641
Maurice E.B. Owens
Chief of Program Integration and Evaluation Branch
WH 586
Analysis and Evaluation Division
U.S. Environmental Protection Agency
401 M St. S.W.
Washington, D.C. 20460
(202) 965-1634
Maris Lucis
Head, Special Studes Branch
Air Resources Branch
880 Bay St., 4th Floor
Toronto, Ontario M5S 1Z8
CANADA
(416) 965-1634
Mary Swanson, Thomas Franz and Paul D. Capel
Graduate Students and Rapateurs
Environmental Engineering Program
Department of Civil and Mineral Engineering
University of Minnesota
Minneapolis, MN 55455
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