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

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9

11

13

15

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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!