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Evidence of agricultural air pollution in Hell’s Canyon National Recreation Area:
Implications for natural and cultural resources
Linda Geiser, USDA-FS, PNW Region Air Program, Corvallis, ORAndrzej Bytnerowicz, USDA-FS, Pacific SW Research Station,
Riverside, CAAnne Ingersoll, USDA-FS, PNW Region Air Program, Corvallis, ORScott Copeland, Cooperative Institute for Research in the
Atmosphere, Lander, WY
The Snake River valley with its moderate climate and abundant food resources, has long been inhabited by humans.
Forest Service archeologist Bruce Womak recreates rock art using local clays as pigments in Hells Canyon National Recreation Area.
Is Rock Art Threatened
by Air Pollution?
A perception exists among area archeologists that ancient pictographs and petroglyphs are fading and eroding in Hell’s Canyon NRA.
One Day Lichen Trip
• Managers, archeologists, botanists, and air quality specialists went for a 1 day look- &-see river trip.
• We collected grab samples of lichens near the rock art and analyzed for N, S, metal levels
• During day long jet boat trip, we noticed high nitrophytic lichen cover on trees visible form the river.
• Lichen N & S levels were very high compared to other remote sites, in the upper range of polluted and urban sites, other elements were within expected ranges for remote sites.
• Unanticipated conclusion: Atmospheric N & S deposition could be a problem.
• But what forms of N & S are depositing? Is the problem limited to the river banks?
One Day Lichen Trip Results
1-Week Lichen Study, 2000
• 4 tributaries, 3 primary and 1 secondary to the Snake R.
• 4 plots per tributary, 3 km transects
• 16 plots total• Plots restricted to
net-leaf hackberry-bluestem bunchgrass plant community.
Lichen %N
Lichen cover
Bark pH
Lichen survey
Measured:• Nitrophilous
lichen cover, • Lichen N &S
content, • Bark pH, • Lichen
community composition
Collected habitat data.
1-Week Lichen Study Results
Nitrophilous lichen cover was very high along the main river banks and much lower at sites >0.4 km
1-Week Lichen Study ResultsRock lichen % N was highest close to the river and enhanced at all sites. Rock lichen % S was highest close to the river but background at other sites.
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9%
Nitr
ogen
in X
. cum
berla
ndia
HC
NR
A, 0
km
CR
GN
SA
, ele
vate
d
HC
NR
A, >
=0.4
km
Col
orad
o, e
leva
ted
Reg
iona
l bac
kgro
und
Chart
a b b b c
1.71
1.42
1.351.31
1.08
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
% N
in X
. cum
berla
ndia
0 10 20 30 40 50 60 70
Xanthoria Cover
Linear Fit
% N in X. cumberlandia = 1.3241 + 0.0072 Xanthoria Cover
RSquare
RSquare Adj
Root Mean Square Error
Mean of Response
Observations (or Sum Wgts)
0.691978
0.672727
0.10717
1.476667
18
Summary of Fit
Model
Error
C. Total
Source
1
16
17
DF
0.41283436
0.18376564
0.59660000
Sum of Squares
0.412834
0.011485
Mean Square
35.9444
F Ratio
<.0001
Prob > F
Analysis of Variance
Intercept
Xanthoria Cover
Term
1.3241637
0.0071766
Estimate
0.035848
0.001197
Std Error
36.94
6.00
t Ratio
<.0001
<.0001
Prob>|t|
Parameter Estimates
Linear Fit
Bivariate Fit of % N in X. cumberlandia By Xanthoria Cover
% N in X. c. = 1.3241 + 0.0072 Xanthoria Cover
r sq adj = 0.67
% N in rock lichens and bark cover of nitrophilous lichens were strongly correlated.
0.09
0.10
0.11
0.12
0.13
0.14
0.15
% S
in X
. cum
berla
ndia
CR
GN
SA
, ele
vate
d
Col
orad
o, e
leva
ted
HC
NR
A, 0
km
Reg
iona
l bac
kgro
und
HC
NR
A, >
=0.4
km
Chart
a a ab b b
0.138
0.1250.123
0.0990.097
Bark pH data was consistent with deposition of ammonia, as opposed to acid forms of N
Cover Class n Mean SE t Test df Prob > |t|< 50 % cover 21 6.55 0.04> 50 % cover 84 6.39 0.041 2.849 66.7 0.0058
Table 3. Welch’s t test of hackberry bark pH in two cover classes of epiphytic lichens.
6
7
pH
bark
Rac
omitr
ium
Xan
thor
ia
Mel
anel
ia
Phy
scia
Chart
a a b b b
6.776.65
6.19
6.045.99
1-Week Lichen Study Results
Kirk1
Kirk2
Kirk3
Kirk4
Klop1
Klop2
Klop3
Klop4
Light1
Light2
Light3
Light4
Pitts1
Pitts2
Pitts3
Pitts4
Cancon
Colfur
EvepruFlasorc
Leplic
Lepmic
Melele
Melsubar
Melsubau
Melsube
Melsubo
ParsulPhaorb
Phasci
Phyads
PhyaipPhyamePhycae
PhyentPhyper
Physte
Phyten
Usnlap
Xanfal
Xanore
Xanpli
Xanpol
Easting
Northing
Xanthoria cover
Physiaceae coverXancum % N
Species richness
Axis 1
Axi
s 3
Transect distance
0 km>= 0.4 km
Lichen communities on the valley floor were:
• Similar to each other• Correlated with other N
deposition indicators• Different from lichen
communities along tributaries (MRPP, p= 0.037, A = 0.0275).
1-Week Lichen Study Results
Lichen parasites and parasymbionts were prevalent throughout the study area
Melanelia Physcia Xanthoria
1-Week Lichen Study Conclusions
• Lichen-indicated N deposition was high throughout the study area compared to other remote sites in the Pacific Northwest and northern Rocky Mountains.
• N deposition was highest on the valley floor. • NH3 is a likely source of N on the valley floor• S deposition might be high along the Snake
valley floor, but not elsewhere.• N& S-containing air pollutants may threaten
archeological and ecological resources
1 Year Passive Monitoring Study
• New questions: Is the river a source of ammonia? What other N- and S- containing pollutants are present? Is there an overlaying regional contribution? Are pollution levels high enough to threaten other natural resources or to damage rock art?
• Passive sampling at 5 stations along the Snake R in Hells Canyon. Quantified biweekly-monthly mean ambient NH3, NOx, NO2, SO2, H2S.
• Continuous ozone measurements in spring and summer at the IMPROVE site in Oxbow Village, OR (HECA).
• Daily NH4NO3 and (NH4) 2SO4 concentrations in fine particulates from HECA for study period.
• Air mass back trajectories for HECA.
Results: Ozone
0
10
20
30
40
50
60
70
80
07/01/02 07/11/02 07/21/02 07/31/02 08/10/02 08/20/02 08/30/02 09/09/02
Measurement Date
Ozo
ne
co
nc
en
tra
tio
n (
pp
b)
Max Average Min
Average, minimum, and maximum daily summer ozone concentrations at Oxbow, OR in 2003 were within expected background ranges.
a
Results: NH3, NOx, SO2, H2S
Mean ambient concentrations of N- and S-containing gases from five monitoring stations along the Snake River in Hells Canyon Recreation Area, from July 1, 2002 through June 30, 2003. Only NH3 was high.
Background Ranges for Remote Sites
Source: Bytnerowicz & Fenn. 1996. Env. Poll. 92:127-146
Pollutant 24 hr Ranges
(ppb)
NH3 0.2 -3.6
NO2 3.6-18
NO 1.5-15
Results: Ammonia is episodically enhanced along the valley floor
Ammonia concentrations (ppb) at 5 sites along the Snake River in HCNRA. Values are averages of two replicates during 2-4 week exposure periods from July 1, 2002 to June 30, 2003, marked at the midpoint of the exposure period.
-1
1
3
5
7
9
11
13
15
17
19
J A S O N D J F M A M J J
Mea
n N
H3
conc
entr
atio
n (p
pb)
Cache Creek
Dug Bar
Hells Canyon Dam
Kirkwood Creek
Pittsburg Landing
Background Ranges for Remote Sites
Source: Bytnerowicz & Fenn. 1996. Env. Poll. 92:127-146
Pollutant 24 hr Ranges
(ppb)
NH3 0.2 -3.6NO2 3.6-18NO 1.5-15
IMPROVE Data
• NH4NO3 concentrations in fine particulates at HECA are higher than other western US sites (excluding southern CA) on the 20% of days when visibility is most impaired.
• HECA (NH4)2SO4 was low all year and similar to other western sites.
• The highest NH4NO3 days at HECA occur in winter.
What are sources of N-containing pollutants in Hells Canyon?
Local sources and influences are probably unchanged
•Topography•Animal wastes•Soils and plants•Wildfires
Long distance transport of regional pollutants has increased
Human population growth in states surrounding Hell's Canyon National Recreation Area
0
1000000
2000000
3000000
4000000
5000000
6000000
1850 1875 1900 1925 1950 1975 2000
Year
Idaho
Oregon
Washington
•Agriculture
•CAFO’s
•Fish farms
Unprecedented human population growth has led to intensification of
•Urban and industrial wastes•Vehicle use
http://water.usgs.gov/nawqa/wri94-4001/fig1.html
http://water.usgs.gov/nawqa/
wri94-4001/fig2.html
Manure and commercial fertilizer contribute large amounts of nitrogen to watersheds of Idaho’s Snake River Basin
The Snake River: Ammonia source
• Large scale agriculture in Idaho is a major source of N, P in the Snake R
• Eutrophication causes extensive growth of algae and cyanobacteria which sink to deep, anoxic waters behind Snake R dams; nitrification ceases and NH4 accumulates.
• Rapid algal growth consumes CO2, raising river pH to 9.
• Water released from the bottom of Hells Canyon Dam is high in NH4; 1997 net release of 4.3 million kg NH4 . High pH favors conversion to NH3 and volatilzation.
• NH3 deposits rapidly to vegetation surfaces, especially moist microsites closest to the river
Average monthly ammonia load for Brownslee Reservoir, 1997. Source: Idaho Power Co. Hells Canyon Complex Relicense Application, 2004.
http://www.epa.gov/air/data/geosel.html
1999 Emissions Density NOx
1999 Emissions Density NH3
Regional Ag and Urban Areas: Ammonium Nitrate Source
And Include:• Snake River Basin
• San Francisco Bay Area
• Southern California
1999 Emissions densities vs. 96 hr back trajectory conditional
probabilities on high NH4NO3 days
Conclusions
How do the results of these studies inform us and shape our concerns for natural and cultural resources?
• The intention of Wilderness Act is to preserve places unaltered and untrammeled by humans. CAA Class 1 designation affords the nations highest level of protection for air quality and air quality related values
• Cultural heritage is also protected by law.• Biological, passive, and instrumented monitoring have provided evidence of
– Episodically high ambient NH3 concentrations along the valley floor of Hells Canyon in spring/summer,
– Seasonally high NH4NO3 concentrations in ambient fine particulates in winter, – Enhanced N deposition throughout HCNRA.
• Eutrophication of the Snake River by agricultural fertilizers, anaerobic conditions behind dams, and high river pH explain ammonia production & volatilization. Deposition occurs to vegetation and other surfaces close to the river.
• Western regional agriculture (esp Snake River Basin & southern CA) and urban areas are the most likely sources of wintertime NH4NO3
• High N deposition is linked to many adverse biological and ecological effects, e.g. community composition of plants, aquatic microflora & fauna (often favoring weedy species), soil fertility, water quality, fire frequency,etc.
• Ammonia is highly reactive compound and a strong weathering agent of minerals. There are many reports of urban stone deterioration by air pollution, but very little on effects of ammonia. This aspect needs more study but meanwhile cannot be eliminated, together with higher visitor use, as an explanation of the deterioration observed by FS archaeologists.
• Enforcement of current water quality standards (TMDL) and better regulation of agriculture would reduce pollution.
• Continued monitoring is needed to document future conditions.
US Forest ServiceAnnie Ingersoll, Alexander Mikulin, and John Syzmoniak, Earl Baumgarten, Roy Lombardo, Molly Lowe, Judy Redner, Steve Lucas, Christine & Rachael Bennet , Robert Bachman, Bruce Womak, Kendall Clark , Dave Lebo, Jerry Hustafa, Sarah Jovan
ContractorsMaxaam, 2B Technology, Pacific Analytics, University of Minnesota Research Analytical Laboratory
Thanks to our co-workers and contractors!