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Dissertations and Theses Dissertations and Theses
6-14-1995 The Distribution of Naturally Occurring Soil Radionuclides and Radon Potential of Northwest Oregon
Stuart Graham Ashbaugh Portland State University
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Recommended Citation Ashbaugh, Stuart Graham, "The Distribution of Naturally Occurring Soil Radionuclides and Radon Potential of Northwest Oregon" (1995). Dissertations and Theses. Paper 5015. https://doi.org/10.15760/etd.6891
This Thesis is brought to you for free and open access. It has been accepted for inclusion in Dissertations and Theses by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. THESIS APPROVAL
The abstract and thesis of Stuart Graham Ashbaugh for the
Master of Science in Geology were presented June 14, 1995, and accepted by the thesis committee and the department.
COMMITTEE APPROVALS: Scott F. Burns, Chair
('Marvin H. Beeson
Ansel G. Jo:tttlson
Representative of the Office of Graduate Studies
DEPARTMENT APPROVAL: Marvin H. Beeson, Chair Department of Geology
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
ACCEPTED FOR PORTLAND STATE UNIVERSITY BY THE LIBRARY by On 6' &kU?~ /99& ABSTRACT
An abstract of the thesis of Stuart Graham Ashbaugh for the Master of Science in Geology presented June 14, 1995.
Title: The distribution of naturally occurring soil
radionuclides and radon potential of northwest
Oregon.
Radon, a naturally occurring radioactive gas produced as one of the decay products of soil/rock uranium and thorium, is considered to be a leading cause of pulmonary disease. Gamma spectrometry of 146 samples of soil were used to quantify radon source potential relative to
1 it. h o 1 ogy b y measuring. B.i 214 activity. . o f t h e U238 d ecay series.. Add itiona. . 1 soi . 1 rad ionuc. 1 i. d e d ata ( T h23 2 , Ac 22 8 ,
K40 and Cs137 ) were used to help identify regional source provenance geoc h emistry. an d soi . 1 d eve 1 opment. Ac 228 , Bi. 214 and Th232 activities in northwest Oregon soils range from 40 five to 55 Bq/kg, while K activities range from 53 to
750 Bq/kg.
In northwest Oregon, three radon potential zones are 214 defined by soil Bi activity: 62% falls within Low 1 zones (less than 25 Bq/kg) , 35% falls within Low 2 zones
(25 to 45 Bq/kg) and 3% falls within Moderate zones
(greater than 45 Bq/kg) . Low 1 zones are significantly influenced by proximal volcanic source provenances, while
Low 2 zones and Moderate zones are considered to reflect distal plutonic and/or metamorphic source provenances.
Soil radionuclide activity has been shown to vary wit. h soi . 1 d eve 1 opment. Th 2 3 2 :K4 0 soi. 1 activity . . ratios . an d
Bi214 soil activity are found to increase with soil d eve 1 opment. Th 23 2 :K 4 0 soi• 1 activity . . ratios . o f soi . 1 s developed on, or from previously unweathered rock and sediment range between 0.03 and 0.08. Th232 :K40 activity ratios of soils developed on, or from previously weathered rock and sediment are often greater than 0.12.
Soil radionuclide activity data of this study do not identify areas with known elevated indoor radon. Soil permeability data provided by the Soil Conservation
Service (SCS) do identify the Alameda Ridge area of north and northeast Portland, an area with known elevated indoor radon. In Salem, Soil Conservation Service soil permeability data do not identify areas with elevated indoor radon. However, some areas of Salem with elevated indoor radon have landslides capable of affecting subsurface permeabilities. There is a possibility that subsurface soil permeabilities, favorable for convective soil gas transport and elevated indoor radon, exist at depths greater than those measured by the Soil
Conservation Service. THE DISTRIBUTION OF NATURALLY OCCURRING SOIL RADIONUCLIDES AND RADON POTENTIAL OF NORTHWEST OREGON
by
STUART GRAHAM ASHBAUGH
A thesis submitted in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE in GEOLOGY
Portland State University 1996 ACKNOWLEDGEMENTS
First, I would like to thank my parents for their
support over the years. Without them, this thesis would not be possible. I would also like to thank the geology department faculty members Dr. Scott Burns, Dr. Marvin
Beeson and Dr. Ansel Johnson for their time invested in
this project.
This project was funded by a grant to Dr. Scott Burns
from the Oregon Department of Human Resources, Health
Division. It was administered Ray Paris and George Toombs of the Oregon Department of Human Resources, Health
Division.
Enginn kann tveimur herrum ao pj6na. TABLE OF CONTENTS
PAGE
LIST OF TABLES ...... v
LIST OF FIGURES ...... vii
INTRODUCTION ...... 1
STUDY AREA ...... 7
LOCATION AND GEOGRAPHY OF THE STUDY AREA ...... 7
REGIONAL GEOLOGIC HISTORY OF THE STUDY AREA ...... 10
GEOLOGY OF PORTLAND ...... 14
GEOLOGY OF SALEM ...... 16
PREVIOUS WORK ...... 2 0
SOIL ...... 23
INTRODUCTION ...... 2 3
SOIL PROFILES AND HORIZON NOMENCLATURE ...... 23
SOIL CLASSIFICATION ...... 27
FORMATION OF SOIL HORIZONS ...... 28
RADIONUCLIDE PROPERTIES (URANIUM AND THORIUM DECAY SERIES) ...... 32
URANIUM ...... 32
THORIUM ...... 33
RADIUM ...... 34
RADON ...... 34 iii
PAGE
FACTORS GOVERNING INDOOR RADON ...... 36
RADON SOURCE ...... 3 6
RADON EMANATION ...... 3 8
SOIL GAS TRANSPORT ...... 4 3
METHODS ...... 47
RADON DETECTION ...... 4 7
BI 214 SOIL RADIONUCLIDE TECHNIQUE THEORY ...... 48
FIELD METHODS ...... 51
LABORATORY METHODS ...... 58
GAMMA SPECTROMETRY ANALYSIS ...... 59
MAPPING METHODS ...... 62
RESULTS ...... 64
REGIONAL SOIL RADIONUCLIDE GEOCHEMISTRY ...... 64
PORTLAND AND SALEM AREA SOIL RADIONUCLIDE GEOCHEMISTRY 108
REGIONAL SOIL PERMEABILITY ...... 113
PORTLAND AND SALEM AREA SOIL PERMEABILITIES ..... 115
DISCUSSION ...... 122
EVALUATING INDOOR RADON POTENTIAL ...... 122
WEATHERING AND SOIL DEVELOPMENT 133
SPATIAL DISTRIBUTION OF NATURAL OCCURRING RADIONUCLIDES ...... 140 iv
PAGE
RADON HAZARD POTENTIAL OF NORTHWEST OREGON 141
DEFINING RADON POTENTIAL ZONES ...... 141
LITHOLOGY OF RADON POTENTIAL ZONES ...... 143
PREDICTED INDOOR RADON FOR NORTHWEST OREGON ..... 143
PREDICTED INDOOR RADON FOR PORTLAND AND SALEM . . . 144
CONCLUSION ...... 149
FUTURE WORK ...... 154
REFERENCES 155
APPENDICES
A Description of Soil Sites and Samples ...... 166
B Soil Radionuclide Data ...... 176
C Oregon Department of Human Resources, Health Division. Indoor Radon Data, May, 1994 .... 186 v
LIST OF TABLES
TABLE PAGE
I Nomenclature of Master Horizons ...... 25
II Selected subordinate departures ...... 26
226 III Radium (Ra ) Activities in Rocks ...... 37
IV Measurements of Emanation Coefficients ...... 42 v Radionuclide Photopeaks ...... 61
VI Soil Radionuclide Activities (Bq/kg) of Oceanic and Other Rift Margin Volcanics and Mafic Intrusives ...... 68
VII Soil Radionuclide Activities (Bq/kg) of Cascadian Volcanics ...... 73
VIII Soil Radionuclide Activities (Bq/kg) of Selected Tertiary Marine Sediments ...... 78
IX Soil Radionuclide Activities (Bq/kg) of Missoula Flood Sediments ...... 84 x Soil Radionuclide Activities (Bq/kg) of Portland Hills Silt ...... 88
XI Soil Radionuclide Activities (Bq/kg) of Holocene Flood Plain Sediment ...... 89
XII Soil Radionuclide Activities (Bq/kg) of Volcanic Ash, and Water Laid Mixed Ash and Tuff ...... 92
XIII Radionuclide Activities (Bq/kg) and Ratios of the Clackamas River Terraces ...... 95
XIV Th 232 :K40 Activity• • Ratios• o f E ntiso· 1 s in the Study area ...... 95 vi
TABLE PAGE xv Ac 22a :K40 A ct1v1ty . . Ratios . f or t h e Quachita/Mississippi River Drainage Systems ...... 96
XVI Radionuclide Activities (Bq/kg) of Ultisols ...... 97
XVII Radionuclide Activities (Bq/kg) of Columbia River Basalt Inceptisols on the Eola Hills ...... 99
XVIII Radionuclide Activities (Bq/kg) and Ratios of Ultisols ...... 104
XIX Radionuclide Activities (Bq/kg) Variability Between Soil Horizons 106 xx Soil Bi 214 and Indoor Rn222 Activities for Selected Portland and Salem Area Zip Codes ...... 112
XXI Relationship Between Soil Conservation Service Permeability Classes, Saturated Hydraulic Conductivity and Intrinsic Permeability ...... 114
XXII Soils Properties and Indoor Rn222 Activities for Selected Portland and Salem Area Zip ...... 116
XXIII Basement and Upstairs Living Area Data ...... 126
. 228 . 214 d XXIV Corre 1 ations Between Ac , Bi an 40 232 40 K with Th : K Ratios ...... 136 xxv Indoor Radon Rating System ...... 146 vii
LIST OF FIGURES
FIGURE PAGE
1 Ra d ionuc. 1 i. d e Decay Series. o f U 2 3 8 an d T h2 3 2 ...... 2
2 Location of Study Area ...... 8
3 Physiographic Provinces of Northwest Oregon ...... 9
4 Tectonic Map of Portland ...... 15
5 Lithologic Map of Portland ...... 17
6 Geologic Map of Salem ...... 19
7 Generalized Soil Profile ...... 24
8 Radon Recoil Paths ...... 40
9 Typical Intrinsic Permeabilities for a Variety of Sediment and Rock Type ...... 46 214 10 Surface Bi Measurements and Indoor Radon for the Pacific Northwest ...... 49
11 Site Locations of Samples Collected in Northwest Oregon ...... 53
12 Site Locations of Samples Collected in the Portland Area ...... 55
13 Site Locations of Samples Collected in the Salem Area ...... 56
14 Source Provenance Geochemistry 228 40 Scatter Plot Ac vs. K ...... 65
15 Source Provenance Geochemistry 214 40 Scatter Plot Bi vs. K ...... 66 viii
FIGURE PAGE
16 Source Provenance Geochemistry 232 40 Scatter Plot Th vs. K • • • • • • • • • • • • • • • • • • • • • • • • • 67
17 Soils on Siletz River Volcanics, Tillamook Volcanics and mafic intrusives of the Coast Range 228 40 Province Scatter Plot Ac vs. K •••••••••••••••• 70
18 Soils on Siletz River Volcanics, Tillamook Volcanics and mafic intrusives of the Coast Range Province. Bi.214 vs. K40 Scatter Pot1 ...... 71
19 Soils on Siletz River Volcanics, Tillamook Volcanics and maf ic intrusives of the Coast Range Province Th232 vs. K40 Scatter Plot ...... 72
20 Cascadian Soils Ac 228 vs. K40 Scatter Plot ...... 74
21 Cascadian Soils Bi 214 vs. K40 Scatter Plot ...... 75
22 Cascadian Soils Th232 vs. K40 Scatter Plot ...... 76
23 Soils on Tertiary Marine Sediment Ac 228 vs. K40 Scatter Plot ...... 80
24 Soils on Tertiary Marine Sediment B. 214 40 l vs. K Scatter Plot ...... 81
25 Soils on Tertiary Marine Sediment Th232 vs. K40 Scatter Plot ...... 82
26 Soils on Missoula Flood Sediment and Portland Hills silt Ac 228 vs. K40 Scatter Plot ...... 85
27 Soils on Missoula Flood Sediment and Portland Hills silt Bi214 vs. K40 Scatter Plot ...... 86
28 Soils on Missoula Flood Sediment and Portland Hills Silt Th232 vs. K40 Scatter Plot ...... 87
29 Terraces of the Clackamas River ...... 94 ix
FIGURE PAGE
30 Ultisols on Siletz River Volcanics, Columbia River. Basa 1 t an d Boring . L ava Ac 22 s vs. K4 o Scatter Plot ...... 101
31 Ultisols on Siletz River Volcanics, Columbia River. Basa l t an d Boring . L ava B.214i vs. K40 Scatter Plot ...... 102
32 Ultisols on Siletz River Volcanics, Columbia 232 40 River basalt and Boring Lava Th vs. K Scatter Plot ...... 103
33 Ind oor Rn 222 l eve l s vs. Soi. l B i. 214 Activities . . . for the Portland Area ...... 110 222 214 34 Indoor Rn levels vs. Soil Bi Activities for the Salem Area ...... 111 222 35 Indoor Rn levels vs. Soil Permeability for the Portland Area ...... 118
222 36 Indoor Rn levels vs. Soil Permeability for the Salem Area ...... 119
37 Soil Permeability vs. Basement and Upstairs living areas Data in Portland ...... 128
38 Soil Disturbance in Salem vs. Portland Area 132
39 Bi'214 vs. T h232 re 1 ative ' to T h232 :K40 ratios' ...... 139 222 40 Rn Potential Map of Northwest Oregon Based on Soi'1 Bi. 214 Activity...... 142
41 Predicted Indoor Radon Levels for the Portland Area ...... 145
42 Predicted Indoor Radon Levels for the Salem Area ...... 148 x
LIST OF PLATES
PLATE
1 RADON POTENTIAL ZONES OF NORTHWEST OREGON.
2 SITE LOCATIONS OF SAMPLES.
3 RADON POTENTIAL ZONES OF PORTLAND, OREGON.
4 RADON POTENTIAL ZONES OF SALEM, OREGON. INTRODUCTION
Radon, a naturally occurring radioactive gas produced as one of the decay products of the uranium and thorium series (Figure 1), was first identified as a unique substance by Ernest Rutherford in 1890 while working with thorium oxide. Shortly thereafter, Fritz Dorn termed this ionizing gas as radium emanation, or radon, as it is referred to today (Wilkening, 1990).
The effects of prolonged exposure to radon and radon decay progeny were observed as early as the sixteenth century. Miners working in pitchblende mines at
Schneeberg, Germany and Joachimsthal, Czechoslovakia were often plagued with pulmonary diseases, commonly referred to as Bergkrankheit or mountain sickness (Miller, 1990).
Until the mid 1950's, exposure to elevated radon and its decay products was primarily viewed as isolated cases and generally considered to be associated with industrial and mining residuals enriched in uranium and thorium.
In 1956, Hulquist, a Swedish scientist, first addressed the issue of potential radon exposure to populations other than those closely associated with industrial and mining residuals enriched in uranium and U238 Series Th 232 Series
1»u ZltU lllTh 4.47 x 10'y 2.45X IQSy - ~ 1,41x10 10y Zllpa"' i415 420) a (4 72. 4 78) 1,17 min z211Ac 6.13h noTh Zll>fh 24.1 d 7.54X 10"y 128fla 2l•Ra ----- 5.75 'I 0(462 .• ., 3.66 d
n(569 545)
22!fln a 1•eo.,,, 55.6 s Radon
Radon <1(629)
• 15491 l•'f>o l•?po
150ms 298 ns l•lpo l'"Po l'°Po 3.11 min ---..- ....,_164 us 138 d n!B 19, 1•oa. 01530) ~ mpb l•tpb 110pb Mpb 10.6 h 26,8 min 22.3 y SI able '°"II 3.05 min
238 232 Figure 1. Radionuclide decay series of U and Th • Half-life for each isotope is listed below (Modified from Nero, 1988). N 3 thorium (Cross, 1990). This viewpoint, that elevated exposures were isolated cases, changed in 1984 after the discovery of elevated indoor radon levels in the Reading
Prong region of southeastern Pennsylvania generated widespread public and scientific interest over radon related health issues (Hopke, 1987) .
Radon and radon decay progeny (polonium, bismuth and lead) are considered to be the principal components of natural radiation exposure to the general population (Nero and others, 1990). Although the hazards associated with radon and its decay progeny are considered to be less for the general population than for those directly exposed to with industrial and mining residuals enriched with uranium and thorium, it is estimated that the average lifetime risk of lung cancer caused from exposure to radon and radon decay progeny is at 0.4 percent, or approximately
10,000 cases of lung cancer annually within the U.S. population (Nero and others, 1990).
In 1984, the Environmental Protection Agency (EPA) established its radon division to study the health effects of indoor radon. That same year, the Bonneville Power 4
Administration (BPA) in Portland, Oregon initiated its weatherization program. Under the BPA's weatherization program concerns arose about how the weatherizing of buildings would affect the quality of indoor air. Radon levels of indoor air within the BPA's service area needed to be studied.
In 1988, the Oregon Health Division initiated the
Oregon Radon Project (Paris, 1990). In 1991, the Oregon
Health Division, in cooperation with Portland State
University, selected the northwest portion of the state for a closer examination of the soil radon production potential based on the variation and distribution of
232 228 natural background thorium (Th ), actinium (Ac ),
214 40 bismuth (Bi ) (Figure 1) and potassium (K ) activities in soils. Radionuclide activities were obtained by gamma spectrometry of non-irradiated soil samples.
Five factors are considered to govern indoor radon concentrations: 1) source (radium concentration), 2) soil and/or bedrock properties (permeability and moisture content), 3) groundwater, 4) the interface between buildings and the underlying soil and/or bedrock, and 5) 5 building ventilation (Nero, 1988) . Source, as defined in 226 this study, is the amount of radium (Ra ) present in soil, sediment or bedrock. The immediate daughter 226 222 218 214 . 214 products of Ra are Rn , Po , Pb and Bi . When
. . f . 1 . b . . b 226 222 d cond itions o equi 1 rium exist etween Ra , Rn an
Bi. 214 , Bi. 214 can b e use d to estimate . Ra 226 activities.. . .
This study primarily focuses on the source of radon
( Rn 222) b y measuring . t h e natura 1 Bi . 214 activity. . o f soi . 1 s.
Soil and/or bedrock properties, including: permeability, 222 bulk density and Rn emanation, along with possible interactions between soil, bedrock and buildings are also addressed.
The principal objectives of this study are to: 1) measure the variation of naturally occurring rad ionuc. l'd1 es, speci'f' ica 11y Bi.214 f rom t h e U238 series,. Th232 and Ac 228 f rom t h e Th232 series. ( F igure. 1 ) an d K40 in. northwest Oregon soils, and 2) determine the extent to wh ic. h soi . 1 Bi . 214 activity. . a ff ects in. d oor ra d on ( Rn 222) levels in northwest Oregon. These objectives were 214 accomplished by comparing soil Bi activity data of soil and/or bedrock to soil and/or bedrock property data. 6
Areas chosen for evaluating how source and soil and bedrock properties affect indoor radon include the cities of Portland and Salem. Both cities are known to have elevated indoor Rn222 levels (Toombs, 1985). Elevated indoor Rn222 levels, as defined in this study, refer to activities above 4.0 pCi/l. Moderate and low indoor Rn222 levels are defined as the activity ranges 2.0 to 4.0 pCi/l and 0.0 to 2.0 pCi/l respectively.
The final products of this study are: 1) a radon source potential map for northwest Oregon based on the capacity for soil radon generation and 2) radon source potential maps of Portland and Salem based on the capacity for soil radon generation. These source potential maps show the Bi214 activity levels characteristic of the dominant sediment and rock for the geologic provenances represented in the study area. 3) Another set of maps of
Portland and Salem exhibit the combined effects of both source and soil and/or bedrock properties. 7
STUDY AREA
LOCATION AND GEOGRAPHY OF THE STUDY AREA
The study area encompasses approximately 48,500 km2 of the northwest portion of Oregon (Figure 2) . The area is bounded by the Pacific Ocean to the west, the Columbia
River to the north, the convergence of the Coast and
Cascade Ranges to the south, and by leading western edges of the Blue Mountains Province to the east. The area lies within 44° and 46° north latitude, and 121° and 124° west longitude. Topography in the study area is characterized by: 1) flood plains and gently rolling hills in the
Willamette Valley Province, 2) broad, flat, dissected plateaus in the Deschutes-Umatilla Plateau and Ochoco-Blue
Mountains provinces, and 3) mountainous terrain of the
Coast Range and Cascade provinces (Figure 3).
The regional climatic regime in the study area is characterized by relatively warm, dry summers, and cool, wet winters. Climatic diversity within the study area results in part from distance from the Pacific Ocean, impedance of marine air from the Pacific Ocean landward by 124° 117°
Washington 46° 46° ~ ({j (JJ u 0 .,,u 4-1 ·..-; u ({j 0..,
42° I I I I I 42° California Nevada 124° 0 Scale 100 Miles 117° Figure 2. Location of study area. CX> 124° 121°
46°- Washington
:::1 m (IJ .w bl ,..,ru ~ ~ ~ .w ,..,ru Cl] (IJ ,.., lt1 bl .,.., 0 J.J u .,.., ~ ~ :S ~100 Milas (IJ I 't1 l'IJ lt1 Q) {) .w Cl] ru ~ u Cl] Ochoco-Blue 8
High Lava 44° Plains
Figure 3. Physiographic provinces of northwest Oregon (Modified \.0 from Walker and MacLeod, 1991) . 10 the Coast and Cascade Ranges, and surface form and elevation (Jackson, 1985) . Approximately 80 percent of the state population resides within boundaries of the study area (Murphy, 1993).
REGIONAL GEOLOGIC HISTORY OF THE STUDY AREA
The tectonic and depositional history of the Oregon and Washington continental margin, through the Cenozoic era to present, has been marked by underthrusting, transcurrent faulting and extension during oblique convergence between the North America and oceanic plates
(Snavely and Wells, 1991). These tectonic elements divide the study area into five distinct physiographic provinces
(Figure 3): 1) Coast Range Province, a north-south trending chain of mountains typically 300 to 1000 meters in elevation situated just inland from a continuous strip of shallow inlets, bays, estuaries, dune fields, terraces and headlands along the Pacific Ocean; 2) Willamette
Valley Province, a broad, north-south trending structural trough (approximately 160 km long, 60 km wide) comprised of hills (200-400 meters in elevation), basins, and broad 11 alluvial flats; 3) Cascade Province, (Western and High
Cascades), a linear chain of mountains in excess of 500 meters elevation, with volcanic peaks in excess of 1000 meters elevation; 4) Deschutes-Umatilla Plateau Province, a broad, relatively flat highland with elevations up to about 1000 meters; and 5) High Lava Plateau Province, a south-southeast trending plateau with elevations in excess of 1500 meters (Orr and others, 1992}.
Much.of western Oregon is comprised of an essentially continuous north-south trending forearc basin formed during the Paleocene to Middle Miocene time (Niem and
Niem, 1984; Snavely and Wells, 1991; Yeats and others,
1991) . During this time, essentially continuous sedimentation was punctuated by episodic volcanism
(Snavely, 1991). These sediments are largely composed of pre-Tertiary plutonic rocks, metamorphic rocks, and volcanics (Chan and Dott, 1983; Heller and others, 1985), derived in part from the Idaho Batholith and adjacent terranes, the Klamath Mountains and Northern Sierras to the south (Heller and others, 1985; Orr and others, 1992}. 12
The onset of Cascade volcanism 44 Ma (Snavely, 1991), parallel to the new continental margin, accompanied the waning and eventual quiescence of volcanism along the
Challis volcanic axis to the east (Wells and others,
1984). Prior to, and during the onset of early Cascade volcanism, arc volcanic rocks of the Clarno Formation erupted between the Challis and Cascade volcanic axis.
Contemporaneous with initial Cascade arc volcanism, several volcanic and intrusive episodes found today in the
Coast Range occurred proximal to earlier island arc volcanism: Tillamook Volcanics, at about 44 Ma, followed closely by Goble Volcanics around 40 Ma (Wells and others,
1984) .
About 38 to 35 Ma, a regional unconformity throughout much of the Pacific Northwest marks the end of early
Cascade volcanism and records widespread subsidence in the arc, back arc and forearc (Snavely and Wagner, 1963; Wells and others, 1984). At approximately 37 Ma, forearc deformation, accompanied by regional uplift and erosion of
Eocene subaerial volcanic piles, produced a number of shelf basins with thick deposits of fossiliferous basaltic 13 sandstone and conglomerate proximal to basaltic highland peripheries (Snavely and Wells, 1991).
Regionally extensive rhyodacitic ash flows of the
Western Cascades at about 35 Ma mark the base of a thick sequence of Oligocene and lower Miocene silicic ash flows, tuffs and lavas in the Cascade arc (Wells and others,
1984). These extensive rhyodacitic ash flows are contemporaneous with the onset of thick sequences of tuffaceous siltstone and arkosic sandstone in the axial parts of the Basin (Snavely and Wagner, 1963; Snavely,
1991) . Time equivalent ash flow units east of the Cascade arc, also derived from the Cascade arc, make up a significant portion of the 34 to 18 Ma John Day Formation
(Robinson and Brem, 1981) .
Regional uplift in the forearc basin in early Miocene time restricted marine deposition to the west flank of the
Oregon Coast Range and the adjacent continental shelf
(Snavely, 1991). Flows of Columbia River basalt contemporaneous with regional deformation in western
Oregon (Snavely, 1991), erupted from fissure systems in northeastern Oregon, eastern Washington, and western Idaho 14 between 16.5 and 6 Ma and traversed into western Oregon through the Columbia transarc lowland (Beeson and Tolan,
1990).
Post 9 Ma maf ic to silicic volcanism in Oregon is marked by an apparent eastward shift of the Western
Cascade volcanic arc, close to the High Cascade axis
(Wells and others, 1984). Extensional faulting, accompanied by High Cascade lavas have dominated since 4.5
Ma (Taylor, 1981; Wells and others, 1984).
GEOLOGY OF PORTLAND
Within the Willamette Valley Province lies a number of small basins. Two of these basins, the Portland and
Tualatin basins, have been interpreted to be pull-apart basins formed by right-lateral strike slip and dip slip faults as part of the regional tectonic setting (Beeson and others, 1989b) (Figure 4).
Within the Portland and Tualatin lowlands, Pliocene to Pleistocene Troutdale Formation, Miocene Columbia River
Basalt, Cascade volcanics, and Boring Lava are overlain by
Late Pleistocene fine and coarse grained catastrophic 15
XT \ \
EXPLANATION
-+---···- AHTICUNI- ---lllCA• ... -,ID-CCNCIAUD. ---- STNCLINf
LI...U HOMOCllNf---...... _.... .,._
----'------fAIJlT-1.t.1 .-..a..u. C»il...... ,.,. - ..._____ THIUSTfAIJlT·._....,..., __,
--;;....--STlllCf-SUPfAUt.f••t----Of•unva-•tNT
ANALYZED IOtfHOlE
IASIN SCAlf s io iso ..
Figure 4. Tectonic map of Portland (From Beeson and others, 1989a) . 16 flood deposits from Glacial Lake Missoula and Holocene alluvium (Beeson and others, 1989b, 1991; Madin, 1990)
(Figure 5) .
Separating the Portland and Tualatin basins are the
Tualatin Mountains, a northwest-southeast trending highland dominantly composed of Miocene Columbia River basalt, Pleistocene Boring Lava, and Quaternary sediment
(Beeson and others, 1989b, 1991; Madin, 1990). Elevations within the Portland area higher than 90 meters are often covered with a varying thickness of loess (Beeson and others, 1989b, 1991; Madin, 1990).
GEOLOGY OF SALEM
Within the Salem area to the south, Tertiary marine sediments and Columbia River basalts are exposed along the western Willamette Valley basin margin and fault bounded anticlines. Quaternary landforms including early
Pleistocene pediments, middle to late Pleistocene dissected gravel terraces, late Pleistocene catastrophic flood deposits, and recent alluvium blanket the Willamette
Valley floor and adjacent basins (Bela, 1981; Roberts, 17 ,. 122 ° 52' 30" f :~ 122 ° 30' 00" 45 ° 37' 30"
~,,.~111111111mmma~~~ 45°37'30" Li tholl ogy
Qaf - Alluvium "•d artificial fill.
Qol - Alluvium
Qfc - Coarse-9r1•in1d facies (Missoula Flood sediment)
Q f f - F i n e - 9 r a i\o • d f a c i • s •~ (llissoul~Flood sediment) Ill QT b - ao r i n 9 L G11a ~ QT s - Tr o" t d a I el Form a I i o n .QI- Clackamul River terraces
Tar - SandJ Rilcr llud1lon1 equivalent
Tc r - Co I um~i a IRi v e r b a• a I t
hh - loverly lights basalt
~ loess - loco.ions where loess is greater •~ than five fe~tthick at the surface. I Scble
0 2 I 3 4 5 I.Ii I es t .· 0 3 14 6 7 8 45 Q 22' 30" jL<«U«t 2 5 f 45 ° 22' 30"~~~~~-~-~~ Kilometers 122 ° 52' 30" .·. 122 ° 30' 00" Figure 5. Lithologic map of Portland (Generalized~fromBeeson and others, 1989b, 1991; Madin, 1990). 18
1984; McDowell, 1991; Yeats and others, 1991; Reckendorf,
19 9 3 ) (Figure 6 ) . I H :t: •' 19
.,
.I• "
< 123 ° 15' 00" t 123° 00' 00" 45° 00' 00" L tho I o 9!Y 45° 00' 00" • Qal - Recent river al lluvium .
• Qlg - Linn gravel .
• Qth - Higher terrace dfposits (glacial-fluvial deposits).
Qtl - Terrace depositslof the Wi I lamette River, tributary rivers and streams, and bottom lands. ~ Qtm - Middle terrace dlposits (glacial-f luvial deposits).
Tcr - Columbia River B~saltGroup.
Toe - Eocene-OJ igocene ~arinesedimentary rock.
f"7\!l Landslide - Basalt and lLLJ ixei basalt and marine col luvium. N Sc a I e
0 2 3 44° 52' 30" Mi I es 123 ° 15' 00" Figure 6. j 123° 00' 00" Geologic map of Salem from ~ (Generalized Bila, 1981) . Kilometers
;T t l I; ' 20
PREVIOUS WORK
Although epidemiological studies of miners supported the idea that radiation emitted by radon and its decay progeny caused pulmonary diseases, studies on non-mining populations did not begin until the 1970's (Cross, 1990).
In the early 1970's, the National Council on
Radiation Protection embarked on a program to examine and evaluate sources of ionizing radiation exposure to the
United States population (NCRP, 1975). NCRP Report No. 45
(NCRP, 1975) was the first in a series of reports which compiled data on the geographical variability of natural background radiation exposure in the United States.
Myrick and others (1983) focused their attention on a selected group of soil radionuclides in the United States.
Their results helped define average nationwide concentrations. of Ra 226 (Bi. 214 ) , Th 232 , and U238 . Average soil concentrations were determined to be 1.1 pCi/g, 0.98 pCi/g, and 1.0 pCi/g respectively (Myrick and others,
1983) . 21
The first comprehensive report on the radon potential of the Pacific Northwest based on radiometric data was published in 1989 (Duval and Otton, 1989) . Aerial radiometric surveys measuring the gamma-ray flux density of Bi214 were used in conjunction with one-degree by two degree geologic maps of the area to produce a regional assessment of the radon potential for the area. Duval and
Otton (1989) noted the importance of physical properties of soil and surface deposits, including permeability and moisture, as essential components in assessing the radon potential for an area.
Prior to the Oregon Radon Project, Toombs (1985) identified elevated indoor radon in the north Willamette
Valley, Portland and Salem vicinities, using alpha track detectors. The Alameda Ridge area of north and northeast
Portland and the Eola Hills area of West Salem were specifically mentioned as areas with elevated levels of indoor radon.
Paris (1990), compared indoor radon alpha track data from the Oregon Department of Human Resources, Health
Division to indoor radon data of the Bonneville Power 22
Administration and showed that there was no significant difference between the two sets of data when the length of the sampling period was greater than 90 days. This report placed a lower limit on the time required to obtain accurate indoor radon measurements representative of annual exposure rates. Similar findings were found in an analysis of indoor radon for Summit County, Ohio (Harnapp,
1994).
The most recent radon potential evaluations using geologic data for the Pacific Northwest are those of Otton and others (1993) and Schumann (1993). In both evaluations aerial radiometric data collected during the
National Uranium Resource Evaluation (NURE) Program (1975-
1981) were used to evaluate the radon potential. Otton and others (1993) and Schumann (1993) consider Oregon to have low to moderate radon potentials. Occurrences of elevated radon are interpreted to be controlled by soil and rock with high permeabilities. 23
SOIL
INTRODUCTION
The term "soil" has a variety of definitions (Buol
and others, 1980; Birkeland, 1984). The definition which
is used in this study is: "A soil is a natural body
consisting of layers or horizons of mineral and/or organic
constituents of variable thicknesses, which differs from
the parent material in their morphological, physical,
chemical and mineralogical properties, and biological
characteristics; at least some of these properties are pedogenic" (Birkeland, 1984} .
SOIL PROFILES AND HORIZON NOMENCLATURE
The vertical arrangement of all the soil layers or horizons from the uppermost layer(s}/horizon(s), down to the parent material is referred to as the soil profile
(Birkeland, 1984) (Figure 7). Most soil profiles can be categorized into prominent or master horizons (Table I) .
Surface or near surface horizons relatively high in organic matter are designated 0 and A horizons. The only 24 difference between the 0 and A horizons is the amount of organic matter present (Table I) (Birkeland, 1984). In some ~nvironments, leaching at the base of the O or A horizon forms a horizon referred to as an E horizon.
Depth (cm) Soil Horizon
8 0 0 A 16
24 E
B
72
A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A c A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A ~ A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A 13 6 A A A A A A A A A h A
Figure 7. Generalized soil profile. 25
TABLE I
NOMENCLATURE OF MASTER HORIZONS
O horizon - Surface accumulation of mainly organic matter overlying mineral soil; may or may not be, or has been, saturated with water.
A horizon - Accumulation of humif ied organic matter mixed with mineral fraction; and the latter is dominant. Occurs at the surface or below the O horizon.
E horizon - Usually underlies an 0 or A horizon, characterized by less organic matter and/or fewer sesquioxides (compounds of iron and aluminum) and/or less clay than the underlying horizon. Horizon is light colored.
B horizon - Underlies an 0, A, or E horizon, shows little or no evidence of the original sediment or rock structure. Several kinds of B horizons are recognized, some based on the kinds of materials illuviated into them, others on residual concentration of materials.
K horizon - A subsurface horizon so impregnated with carbonate that its morphology is determined by the carbonate. Authigenic carbonate coats or engulfs all primary grains in a continuous medium to make up 50 percent or more by volume of the horizon.
C horizon - A subsurface horizon, excluding R, like or unlike material from which the soil formed or is presumed to have formed. Lacks properties of A and B horizons, but includes materials in various stages of weathering.
R horizon - Consolidated bedrock underlying soil.
Modified from Birkeland, 1984. 26
There are four master subsurface horizons. The uppermost subhorizon is the B horizon. This horizon underlies the 0, A, and/or E horizon and overlies the parent material (designated C and/or R horizons) . In arid climates, horizons impregnated with carbonate may be present. These horizons are designated as K horizons.
However, the climate regime for the study area is not conducive for the development of K horizons. Further division of these master horizons may include some of the subordinate departures listed in (Table II) .
TABLE II
SELECTED SUBORDINATE DEPARTURES b Identifiable buried soil horizons with major genetic features developed prior to burial. May be deeply buried and not affected by subsequent pedogenesis; if shallow, they can be part of the younger soil profile. c Concretions or nodules cemented by iron, aluminum, manganese, or titanium. g Horizon in which gleying is a dominant process, that is, either iron has been removed during soil formation or saturation with stagnant water has preserved a reduced state. k Accumulation of alkaline earth carbonates, commonly
CaC03 . 27
TABLE II
SELECTED SUBORDINATE DEPARTURES (continued) t Accumulation of silicate clay that has either formed and subsequently been translocated within the horizon or has been moved into the horizon by Illuviation, or both. w This symbol is used with B Master horizons to indicate the development of color or structure, or both, with little or no apparent illuvial accumulation of material x Subsurface horizon characterized by a bulk density greater than that of the overlying soil, hard to very hard consistence, brittle, and seemingly cemented when dry.
Modified from Birkeland, 1984; Soil Survey Staff, 1992.
SOIL CLASSIFICATION
Classification schemes are typically developed by systematically grouping similarities and dissimilarities based on physical, chemical and/or morphological properties. As such, the classification scheme and systematic designation of soils have included many proposals. Many of the early approaches in soil survey and classification were based on the geology and composition of soil-forming material (Buol and others, 28
1980) . Today the standard classification scheme used in the United States is based on that from Soil Taxonomy
(Soil Survey Staff, 1975). This classification scheme is largely quantitative. Soil pH, temperature, moisture, base saturation, color, and texture are just some of the criteria used in this classification scheme. The Keys to
Soil Taxonomy (Soil Survey Staff, 1992), based from the
Soil Taxonomy (Soil Survey Staff, 1975) classification scheme was used to identify northwest Oregon soil types.
FORMATION OF SOIL HORIZONS
Soil horizonization is an equilibrium process, a process which results in the breakdown of unstable minerals and/or organic constituents and the formation of stable minerals and/or organic constituents. There are two primary processes involved in the development of soil horizons: 1) transformations and 2) transfers.
Transformations include the formation of organic compounds during decomposition of organic matter and the weathering of primary to secondary minerals (Birkeland, 1984).
Transfers on the other hand involve the movement of ions 29 as either soluble or insoluble complexes by the downward percolation of water, capillary rise of subsurface water, root uptake and evapotranspiration (Birkeland, 1984).
Transformations and transfers are responsible for the formation of illuviated (B) and eluviated (E) horizons.
Illuviation refers to the accumulation of new material and/or the absence of leaching, resulting in concentration of residual materials (i.e. clay and iron oxides) within one or more horizons. This accumulation and/or concentration of new and/or residual material is often represented by a distinct vertical change in soil properties, including color, texture, and structure.
Illuviated horizons show little or no evidence of the original sediment or rock structure {Birkeland, 1984) .
Eluviation refers to depleting or leaching. Eluviated horizons are typically light colored and depleted in iron oxides (Birkeland, 1984). Original sediment or rock structure may be absent in some E horizons.
Soils can be classified into eleven soil orders:
Entisols, Inceptisols, Aridisols, Mollisols, Alfisols,
Spodisols, Andisols, Ultisols, Oxisols, Vertisols, and 30
Histisols (Soil Survey Staff, 1992). Parent material, organic content, pH, temperature, and moisture, determine kind of soil (soil order) which forms (Birkeland, 1984) .
All soils start as Entisols. These are soils which show faint signs of pedogenesis (soil forming processes) .
Epipedon development is weak. Entisols are typically represented by A/C or O/C master horizons. From Entisols, soils typically develop into Inceptisols. This soil order is marked by the extension of oxidation below the base of the epipedon to form a cambic (illuviated, Bw) horizon.
Epipedons, if present, are well developed. Inceptisols are typically represented by A/B/C master horizons.
Aridisols, Mollisols, Alfisols, Spodisols, Andisols,
Vertisols and Histisols typically follow Inceptisol soil development. Epipedon properties including percent base saturation, pH, the presence or absence of cements and carbonates, percent organics, and mineralogy determine the proper soil order classification (Soil Survey Staff,
1992) . Discussion of the classification criteria for these is beyond the scope of this study. However, these soil orders, like Inceptisols, are represented by either 31 well-developed horizons and/or horizons characterized pedogenic features. The two remaining soil orders,
Ultisols and Oxisols, represent advanced stages of soil development and weathering. Ultisols differ from other soil orders in that argillic (Bt) horizons have base saturations less than 35% (Birkeland, 1984). The soil master horizons A/B/C or A/E/B/C are typically the soil horizons associated with Ultisols. Oxisols, show the most advanced weathering and soil development of the eleven soil orders. Oxisols differ from the other soil orders by the presence of an oxic horizon, a horizon at least 30 cm thick, few weatherable minerals, greater than 15% sandy loam, silt or clay sized particles, and cation exchange capacities less than or equal to 16 meq/lOOg. A/B/C master horizons are typically associated with Oxisols.
The thickness of Oxisol horizons can be quite extensive, e.g. greater than ten meters thick. 32
RADIONUCLIDE PROPERTIES (URANIUM AND THORIUM DECAY SERIES)
URANIUM
Uranium, element number 92, occurs as three isotopes
(234, 235, 238) in nature. It is the fourth element in the actinide series and is structurally and geochemically analogous to the lanthanide series of rare earth elements
(Schmalz, 1990). Uranium is preferentially concentrated in silicic igneous rocks and late magmatic fluids
(Schmalz, 1990). Uranium commonly forms compounds in either the tetravalent (+4) reduced ionic state or the hexavalent (+6) oxidized ionic state (Muhs and others,
1990; Schmalz, 1990). It is the ionic state of uranium which often determines how readily it moves through the environment. Near surface environments, including soils and environments where oxidation is prominent, often favor uranium in the +6 ionic state. In this ionic state,
2 uranium often forms water soluble uranyl ions (U02 )+
(Schmalz, 1990). The potential exists for significant uranium mobility in oxidizing environments (Muhs and others, 1990). Uranium in reducing environments behaves 33 quite differently. Upon reduction, uranium is reduced to the +4 ionic state uranyl ion and immediately precipitates
(U02 ) (Schmalz, 1990). Low uranium mobility is typically associated with uranium in the +4 ionic state.
THORIUM
Thorium, element number 90 (Figure 1), occurs as only one isotope in nature (232). It is the second element in the actinide series, and as such, exhibits geochemical properties similar to other actinide and lanthanide series elements, and to some degree, the elements in Group IVB
(Schmalz, 1990). It is also preferentially concentrated in silicic igneous rocks and late stage magmatic fluids
(Schmalz, 1990). However, unlike uranium, thorium only occurs in the +4 ionic state, making it relatively immobile (Langmuir and Herman, 1980). Enhanced thorium mobility may occur in the presence of organic ligands by inhibiting thorium adsorption, and in some cases, even promote partial thorium desorption from oxides, clays and colloids (Langmuir and Herman, 1980). 34
RADIUM
One of the intermediate decay progeny of uranium and thorium is radium. Radium, element number 89, occurs as two naturally occurring isotopes (226, 224) in the U238 and
Th232 decay series (Figure 1) . Radium is a divalent alkaline earth metal and exhibits chemical properties and behavior similar to other Group IIA elements (Muhs and others, 1990; Nathwani and Phillips, 1979; Schmalz, 1990).
RADON
The immediate daughter product in the decay of radium is radon, the heaviest gas found in nature at 9.73 g/l at
STP (Figure 1) (Wilkening, 1990). The stable closed electronic configuration of neutral radon atoms in the ground state gives it the basic chemical properties of a noble gas (Wilkening, 1990) and allows it to move though the environment relatively free of chemical impedance.
Two rad on isotopes. ( R n 222 and Rn 220) originate• • f rom t h e U23s and the Th232 decay series respectively. The radon isotope
222 of most concern to human health is Rn , the immediate daughter of Ra226 (half-life 1600 years, U238 series) 35
(Figure l). This concern arises because Rn222 's relatively long half-life of 3.82 days is enough time for it to reach indoor environments. Rn2201 s half-life of 55.6 seconds prohibits much of it from reaching indoor environments.
Both isotopes decay to radionuclides that are chemically active and short-lived (Nero and others, 1990) . The four immediate radionuclides following the decay of Rn222 are:
Po 218 and Pb 214 (lead) and Bi• 214 (Figure. 1) . All have half- lives less than 30 minutes. If these radionuclides are inhaled and become attached to lung tissue, they are likely to decay to Pb210 before removal by lung clearing mechanisms (Nero and others, 1990). Exposure to these rad ionuc. 1 i. d es, particu . 1 ar 1 y p o 218 and p o 214 , is. consi• d ere d to be a significant factor in causing pulmonary diseases such as lung cancer (Nero, 1988; Nero and others, 1990;
Wilkening, 1990). 36
FACTORS GOVERNING INDOOR RADON
There are five factors that govern indoor radon concentrations: 1) source, 2) soil or bedrock properties,
3) groundwater, 4) the interface between the building and the underlying soil or bedrock, and 5) building ventilation (Nazaroff and others, 1989). This study is primarily focused on the first two factors:
1) Source:
a ) t h e d istri. . b ution . o f Ra 226 ( Bi . 214) in. sub sur f ace
horizons.
2) Soil or bedrock properties:
a) the Rn222 emanating power of soil and rock; and
b) soil and rock permeability.
RADON SOURCE
The distribution of radon is closely related to the abundance of uranium and thorium, but most importantly, to its immediate precursor radium. Radium sources include rock, soil, groundwater, and building materials. The principal sources are from weathered rock and soil at or near the ground surface (Nero and others, 1990). Radium 37 is most abundant in felsic intrusive and extrusive igneous rocks and late stage magmatic fluids where concentrations of uranium and thorium are highest (Nazaroff and others,
1989; Schmalz, 1990). Other sources known to be enriched in uranium and thorium, often included as significant sources are: organic rich shale, metamorphosed igneous and sedimentary rocks, and chemical precipitates such as limestone and evaporites (Nero, 1988) . Radium is least abundant in mafic igneous intrusive and extrusive rocks.
Radium (Ra226 ) activities for a variety of rock types are listed in Table III.
TABLE III
RADIUM (Rn226) ACTIVITIES IN ROCKS (BQ/KG)
Rock Classa Example Nf Meanb Range Felsic Extrusives rhyolite 131 71 10-285 Felsic Intrusives granite 569 78 1-372 Intermediate Extrusives andesite 71 26 2-64 Intermediate Intrusives diorite 271 40 1-285 Mafic Extrusives basalt 77 11 0.4-41 Mafic Intrusives gabbro 119 10 0.1-71 Ultramafic Rocks dunite 31 4 0-20 Alkali Feldspathoidal Intermediate Extrusivesc phonolite 138 368 24-769 Alkali Feldspathoidal c Intermediate Intrusives syenite 75 692 4-8930 38
TABLE III
RADIUM (Rn226) ACTIVITIES IN ROCKS (BQ/KG) (continued)
Alkali Mafic Extrusives nephelinite 27 29 6-149 Alkali Mafic Intrusives foidite 8 29 5-67 Chemical Sedimentary Rocksd evaporites 243 45 0.4-335 Carbonates limestone 141 25 0.4-223 Detrital Sedimentary Rockse 412 60 1-992 Clay 40 so 14-198 Shale 174 73 11-992 Sandstone and Conglomerate 198 51 1-770 Metamorphosed Igneous gneiss 138 50 1-1835 Metamorphosed Sedimentary Rocks schist 207 37 1-657
a The classification used for the extrusive and igneous rocks is modified from Williams and others, 1954. Rocks are classified on the basis of whole-rock silica content] felsic > intermediate > mafic > ultramafic) and alkali and calcic feldspar mineralogy. b Arithmetic mean. c Although these rocks have elevated Ra contents, the alkali feldspathoidal rock class is though to constitute less than 1 percent of all igneous rocks (Wollenberg and Smith, 1984). d Includes carbonates. e Includes clay, shale, sandstone, and conglomerates. t N is the number of samples.
Modified from Nazaroff and others, 1989.
RADON EMANATION
The physical and chemical properties of rock, soil and other surficial deposits, govern the fraction of radium atoms that produce radon atoms capable of entering pore spaces, to the total number of radium atoms present
(Wilkening 1990) . This is known as the emanating power, 39
emanation fraction or emanation coefficient. It is a
dimensionless number which indicates how much radon is
available for soil or rock matrix transport. Radon
emanation is directly related to grain size or rock
fracture, grain distribution and orientation, soil
moisture, and matrix characteristics such as porosity.
These physical properties govern the three emanation
components which comprise the emanation coefficient:
direct recoil, indirect recoil and diffusion (Nazaroff and
others, 1989). These three radon emanation components
determine if and how radon enters available pore space.
Direct recoil pertains to radon atoms which terminate
their recoil in the open matrix (pore spaces, cracks, etc.) in soil and rock without backtracking the recoil path. Indirect recoil pertains to radon atoms which have
enough recoil energy to backtrack the recoil path. Radon
atoms close enough to the grain or rock surf ace may escape
by diffusion rather than recoil or indirect recoil.
Figure 8 illustrates direct recoil, indirect recoil and
diffusion, and their implications to radon emanation.
Water is one of the more determinant factors in the radon ,, Soil grain \/ Scale Soil grain I I D' 0.1 µm Fi9ure 8. Radon recoil paths in soil grains. Spherical grains (silt/clay) are in contact at point B. The stippled portion of pore is water-filled. The recoil range, R, of the radon atoms is indicated by the dashed line. Ra atoms, indicated by solid circles, decay, producing an alpha particle and a Rn atom which may end its recoil at the point indicated by the open circle. At A, the Ra atom is too deeply embedded within the grain for the Rn atom to escape. At B and D, the recoiling Rn atom possesses sufficient energy after escaping the host grain to penetrate an adjacent grain. At C, the Rn atom terminates its recoil ~ in the pore water (From Nazaroff and others, 1989). 0 41 recoil emanation component because water films coating grains or crystals act to buffer and absorb the recoil energy, thus reducing the effective recoil range. Lower recoil ranges greatly increase the probability that a radon atom will terminate its recoil in pore spaces. Higher emanation coefficients are typically associated with moist soils. The third component (radon diffusion), with diffusion lengths on the order of 10-9 to 10-28 cm, limits how far radon can be from the grain or crystal surface and escape to pore spaces. Nazaroff and others (1989) consider radon diffusion to be a negligible component in radon emanation. Radon emanation data summarized in Table IV show an approximate emanation coefficient range of 0.02 to 0.7 for various soils, crushed rock and uranium ore (Nazaroff and others, 1989). Radon emanation coefficients for moist soil is virtually constant at 0.35 to 0.4 (Eaton and Scott, 1984). 42 TABLE IV MEASUREMENTS OF EMANATION COEFFICIENTS Material N Moisture content Emanation coefficient a Rock (crushed} 58 unknown 0.084-0.086 (0.005-0.40) Soil 21 unknown 0.30-0.16 (0.03-0.55) Soil 1 dried-105 deg C, 24 h 0.25 Soil 1 33% of dry wt; dried- 200 deg c, 90 h 0.68 Soil 1 air dry 0.09 Soil 2 3-20% of dry wt. 0.41 Soil 1 4% of dry wt. 0.27 Various soils Lava unknown 0.02 Thin organic soils unknown 0.55 Deep agricultural soils 0-70% of dry wt. 0.7 Various soils (Danish} 70 unknown 0.22-0.13 (0.02-0.7} Various soils sand unknown 0.14 (0.06-0.18} sandy loam 7 unknown 0.21 (0.10-0.36) silty loam 7 unknown 0.24 [heavy] loam 12 unknown 0.20 clay 5 unknown 0.28 sand 1 saturated 0.243 uranium ore 17 saturated 0.19-0.10 (0.06-0.26) 0.05-0.03 {0.14-0.07) a numbers in brackets are ranges. (From Nazaroff and others, 1989} 43 SOIL GAS TRANSPORT Soil gas, including radon, migrates through available pore space via molecular diffusion and convective transport (Nazaroff and others, 1989}. The effects of mass transfer processes can be exhibited using two dimensionless numbers Pep (Peclet number} and Nt respectively (Equations 1 and 2) (Nazaroff and others, 198 9) . 1 PeP=keaP0 (µDe) - ( 1) N =fl.P k( µeL 2 l ) -l t 0 Rn (2) where k = intrinsic permeability; B = porosity; f>.P 0 = the air pressure difference between the ground surface and a 222 determined depth; µ = viscosity of Rn gas; De = the bulk 222 diffusion coefficient of Rn ; L = length (distance between ground surf ace and the source depth) ; and ARn = 222 the decay constant of Rn • Pep characterizes the relative importance of convective transport with respect to diffusive migration, and Nt delineates the relative 44 importance of radioactive decay with respect to convective flow as a means of removing radon from the soil pores. Nazaroff and others (1989) summarize mass transfer as follows: 1) for conditions in which Pep>> 1, molecular diffusion is negligible compared to convection; 2) when Pep >> 1 and NT >> 1, the problem may be treated as steady state and radioactive decay may be neglected; 3) when Pep << 1, convective transport may be neglected; 4) for conditions where Pep << 1 and NT >>Pep, convection may be neglected, and the solution is reduced to Poisson's equation (Equation 3): ( 3) V2I +--G -o Rn De where IRn is the radon activity in the soil pores, and G is the volumetric radon generation rate in the soil pores 3 1 (Bq/m- s- ) • Theoretical intrinsic permeability boundaries relative to radioactive decay, transport mechanism (molecular diffusion and convection) , and transport length were determined by Nazaroff and others (1989) . Nazaroff 45 and others (1989) set Pep equal to 1. 0 {the boundary between molecular diffusion and convective transport) and solved fork (Equation 1) with the following parameters: -6 -1 -1 ~p 0 = 3 Pa, € = 0. 5, µ = 1 7 x 10 kg m s , and De = 2 x -6 2 -1 10 m s An intrinsic permeability value (k) of 2.3 x 10 -11 m2 ( 2. 3 x 10 -7 cm 2 ) was o b taine . d ( Nazaroff and others, 1989). Setting N, = 1.0 (Equation 2) and using a length of three meters (in most cases, enough radon is produced by the soil within this distance of a building to sustain elevated indoor concentrations) (Nazaroff and others, 1989), a k value of 5.0 x 10 -11 m2 (5 x 10 -7 cm)2 was obtained. These calculations are useful for evaluating likely mass transfer processes in soil and rock when intrinsic permeabilities are known. Figure 9 illustrates typical intrinsic permeabilities for a variety of sediments and rock types relative to grain size. (/} n c (I)~ Ill t-' ::s Ill ID ::S ID I-'· ::s ...... Q.. Ill Hi Q...... ::s 0 I Ill ' Ill IQ c:: ::s c:: ~ ::s 1-1 o::s ac:: Q.. ~ ::s ID ::S ' p. Pl 0 I-'· ID Cf.I Q.. Cf.II-'· Cf.I Ill Hi Q...... IQ t-' HI 1-'·Hl I-'· 1-1 0 IQ (I) Ill I-'· Hi 1-1 t-' I-'· t-' 1-1 Q.. 1-'0 ::s Pl I ::s ~ ~ Pl ' § ~ < IQ It) Q~ ~ Q CD 1-1 (I)< (I) (/) (/} ' t-' Ill (I) ..... I-'· (I) (I) 0 0 n Pl '11 t-' t-' ::s t-' ...... ::s ~ g g~ '11 Ill Q.. Q.. Q.. Q.. ~ Q.. 11" ~ '< '< ! ! ! ! ! u ! ! ! I I I I I I I I I I I I I I -Log10 k ( cm2} 3 4 5 6 7 8 9 10 11 12 13 14 15 16 I I I I I I I I I I Clean Clean sand or Very fine sand, silt, Clay Soils gravel sand and gravel loess, loam. Oil rocks Sandstone Limestone Breccia, Rocks granite Figure 9. Typical intrinsic permeabilities for a variety of sediment and rock types {Modified from Bear, 1979 and Nazaroff and others, 1989). ~ °' 47 METHODS RADON DETECTION The detection and measurement of Rn222 is based on the ability to detect radiation. Some of the common methods used in the detection and measurement of radon include: Grab-sampling - This device consists of a portable self- contained instrument that uses a scintillation cell/filter to measure alpha particle emittence from Rn222 or its decay progeny. This method of sampling provides real-time measurements for both soil and air samples and is typically not used in the evaluation of long-term radon exposure health issues. Alpha-track detector - This device is also a portable self-contained detector. This device records etchings left behind by the energy released during the alpha decay o f Rn 222 or its. d ecay progeny. This method of sampling can provide both real-time and long term measurement/ assessment data. Charcoal sampler - This device employs the use of a portable sealable sampler. Radon is collected in the 48 sampler, which is then sealed and analyzed for decay progeny gamma em1ttence. f rom B.1 214 (Rn 222 daughter) . This method provides real-time to short-term measurement data. All three methods provide useful information about indoor radon. However, with the exception of alpha-track detectors, multiple sampling needs to be done with the other methods in order to obtain long-term exposure data. BI214 SOIL RADIONUCLIDE TECHNIQUE THEORY This study used a slightly different technique for measuring radon source. The technique used to quantify radon source in this study is based on the premise that Bi.214 , a daughter product of Rn 222 , can be used to accurately quantify the amount of Ra226 generated in soil. This technique should be valid if the following conditions are met: 1) a relationship exists between geology (lithology) and radon source, 2) indoor radon can be correlated to radon source, and 3) measurements of Bi214 222 can reflect radon source quantities, thus radon (Rn ). The preferential concentration of uranium and thorium in silicic igneous rocks and late stage magmatic fluids 49 (Schmalz, 1990) and radium data from Table III (Nazaroff and others, 1989) support the first condition that the 226 occurrence of radon source (Ra ) is related to lithology. The second condition, that indoor radon can be correlated to radon source is also met as illustrated in Figure 10. Figure 10 shows a least squared fit line of 0.42 (statistically significant at the 0.05 confidence level) ,.... 1t.0 ...J::::: 10.or • u • --a. z a.a 0 0 • < 0:: 6.0 • 1 a0:: • 0 ~ -4.0 • - • )( )( w •'*)( <..!) y = 1.4x + 0.7 < 2.0 . .. 0:: • . w .. .. ·. ,. > :..•' .· ...... :; . :· • .. < . o.o~ ..,. N VJ CD ~ 0 0 0 0 0 - SURF ACE RAO IUM (pC!/g) 214 Figure· 10. Sur f ace B.1 measurements an d in . d oor radon for the Pacific Northwest. Average indoor radon within various townships versus the apparent surface radium concentration in the Bonneville Power study area. Only townships with at least 25 sample houses (data points) are included in this graph. Points marked by an X are interpreted to be unusually high areas (stat~stical outliers) that have unusual geologic or soil characteristics. The solid line represents a linear fit to the data with the outliers excluded (From Duval and Otton, 1989). 50 between radon source (surface Bi214 gamma emissions) and average indoor radon (Duval and Otton, 1989) . The third condition, that measurements of Bi214 can reflect radon source quantities, is stated as follows: secular equilibrium, a condition in which parent and daughter ra d ionuc. 1.i d e activities . . . ( R n 222 an d B.i 214) are equa 1 , is possible in a system where the gain or loss of mass is prevented (closed system) . This was of particular concern because the loss or gain of soil radon gas during the analysis could affect the analytical results and subsequent interpretations. In a closed system, a state of secular equilibrium will be obtained given enough time. The equation used to calculate the amount of time required to reach conditions of secular equilibrium is Equation 4. ( 4) D* =N( 1-e-AT) where n* represents the number of parent atoms; A= (ln2)/ T1 ;2i T1 ; 2 = half-life of daughter; and t = time (Faure, 1991) The amount of time required to achieve secular 51 equi. l i . b rium . b etween Rn 222 , p o 21a , Pb214 and B i. 214 is. calculated by starting with Rn222 (parent isotope) and Po218 (daughter isotope) , and sequentially moving down the decay series using the daughter isotope as the parent isotope for the next calculation until Bi214 is reached. Since secular equilibrium approaches but never quite reaches 100%, the author chose 99.5% as an acceptable limit. The amount of time required for these four radionuclides to reach 99.5% secular equilibrium is 30 days. At 30 days, Bi. 214 measurements are representative. o f t h e amount o f R n 222 present in the sample. FIELD METHODS The sampling strategy for this study was centered around collecting soil samples which best exemplify regional geochemical variations. Four source provenances were hypothesized as being primarily responsible for these variations: 1) oceanic island volcanics, 2) proto/modern Cascade volcanics, 3) plutonic and metamorphic sediments, and 4) plateau flood basalts (Orr and others, 1992). The geologic maps of Oregon (1:500,000 scale) of Walker (1977) 52 and Walker and MacLeod (1991) were used to identify locations believed to reflect representative source provenance geochemistry as previously mentioned. Geologic homogeneity and areal extent were also taken into account in the pre-sampling evaluation strategy. By sampling soils from all four source provenances, the impact of these source provenances on radon source in the study area can be determined. Geologic maps (1:24,000 scale) of Bela (1981), Beeson and others {1989b), Madin (1990), Beeson and others (1991) and county soil maps (1:20,000 scale) of Williams (1972), Green (1982, 1983), Knezevich (1982), and Gerig (1985) were used to identify areas in Portland and Salem where geologic and soil data provided homogeneity and areal extent. These data were used in combination with known levels of indoor radon to establish relationships between geology, radon source and indoor radon. One-hundred-forty-six samples were collected from 79 sites along north-south and east-west transects in northwest Oregon (Figure 11, Plate 2). These 79 sites represent soils developed on areally extensive and I' .\. •I I 53 124° 121 ° 46°- - 46° t •"' ,I ! ..,.. Sc a I e r ...... ~. STUDY ...... I AREA +n .... ' •"' ...... WASHINGTON ...... 2: < .... Cz;:l ...... \ u 0 .... .,11:;,p. +"...... r +• ·- ...... " ..... \. u .. I' - ...... """' ~. u ...... r ' f"'' !'! ~'! .... ~{·...... - I ..... I ..... f \ § .... ' ... I - •· I •"' ...... - •"' ...... , ...... CALIFORNIA NEVADA ,.. I ,,, 440 N 44" 124° " 121° Figure 11. Site locations of samples collected in northwest Oregon. See Plate 2. t 54 homogeneous lithology. At least two sites from each major mapping unit of Walker and MacLeod (1991) (Appendix A) were sampled. Of the 146 samples collected, 21 were collected from twelve sites in the Portland area (Figures 11 and 12) and 18 samples were collected from eleven sites (Figures 11 and 13) in the Salem area. 55 122 ° 52' 30" 122 ° 30' 00" 45 37' 30" 45 ° 37' 30" ° PS ,, ' l~ I'. lf') I ,, H ' ~~ <"::::. ~,t P3 P2 41 amed~It . d PS P1 l .i. 9'e P4 to L e ·d e n d P15 t\ G Site ~ f ' O<>. lf') 0 N I H q ; :~ I q ,,~.' .. JI Scali e 0 2 I 3 4 5 U i I es t 0 2 3 v~~s 6 7 8 Kilometers 45 ° 22' 30" 45 22' 30" I ° 122 ° 52' 30" 122 ° 30' 00" Figure 12. Site locations of samples collected in'. the Portland area. '· I " ', '\. }ll ! 56 :i l I Il ~ l ·~ J 123° 15'00" I 123° 00' 00" 45° 00' 00" .. - ~ 45° 00' 00" (l 0 .-1 N .,. -a N ; ..... >.· :;: ::r: :t:o L e g e In d ~ I 0 ... Eola Hills G Site Q 0 SS t> S1 a ;/ .Jsalem S2 S3 ~ 0.. SS S4 ,.. ..,..--, .. _. :- d i;;?Q N :t , ..- S c a I e ~ l,, 0 .3 2 4 l: ·•' Mi I es t I .. ~ I 8 44 ° 52' 30" , l Kilometers 123 ° 15' 00" i i ;~ 44 ° 52' 30" I' 123° 00' 00". Figure 13. Site locations of samples collected in I I the Salem area. t t I I '! .,'. . t 57 The soil horizons of most interest in this study were illuviated horizons. Studies by Asher-Bolinder and others (1990) and Burns and others (1991) have shown that 214 naturally occurring radionuclides, including Bi , are concentrated in illuviated horizons. Soil gas transport was also weighed as a factor in selecting illuviated horizons for the following reasons: 1) with the exception of Ultisols, most B horizons in soils in the study area are within two to three meters of the ground surface, and 2) most radon sources associated with indoor radon are within one meter of the ground surface (Nero and others, 1990). By sampling the illuviated horizons, the maximum radon source potential is taken into consideration. If illuviation has increased the radon source potential to levels no longer indicative of the original radon source typically associated with the parent lithology (C horizon) , an upper limit could be assigned to that lithology based on the relative stage of soil development. Epipedons and eluviated horizons were additionally sampled to help examine if and what radionuclide transfers have 58 occurred between epipedons and eluviated horizons, and illuviated soil horizons. Most samples were collected from soil pits and cut bank exposures where sedimentation, erosion and anthropogenic disturbances had been minimal over the past 100 years. Forested sites were found to be the least disturbed and were preferred over non-forested sites. Samples from active flood plains, hill slopes and wetlands were also sampled for comparing soil geochemistry and soil development between erosional and depositional environments. Parent material, soil horizons, color, texture, and structure, along with site elevation and vegetation were recorded at each site location (Appendix A) . The numbering system developed for the samples gives the site first followed by the horizon, pit number and sample taken. Approximately 30 cm3 of sample from each respective horizon was collected at each site. LABORATORY METHODS All soil samples were air dried at 25 degrees Celsius for 72 hours. To ensure a homogeneous and representative 59 aliquot, samples were crushed to pass through a 20 mesh sieve (<0.87mm diameter). Each sample was then placed in a 500 ml plastic container to the same level (to assure consistent sample geometry) and sealed with a silica gel. Rn222 and Bi 214 were then allowed to reach 99. 5% secular equilibrium with Ra226 (30 days). Samples, in their sealed containers, were then analyzed by gamma spectrometry. GAMMA SPECTROMETRY ANALYSIS The benefit of using unirradiated instead of irradiated samples in gamma spectrometry, is the ability to measure Cs137 activities (atomic bomb product) in soil. Cs137 provides useful information regarding the stability of soil horizons. Cs137 can be used to help delineate soil horizon boundaries, or confirm site/soil disturbance history because it is almost exclusively limited to the O and A horizons (Burns and others, 1991; Meriwether and 137 others, 1995). Lower Cs activities in the 0 and A soil horizons, relative to equivalent horizons of surrounding soils, often imply soil disturbances within the past 30 years (Burns and others, 1991; Meriwether and others, 60 1995). Cs137 activities vary with proximity to source, prevailing wind patterns and elevation. In this study, Cs137 activities of O and A horizons at disturbed sites were found to be less than 10 Bq/kg. Interpretation of Cs137 activities were used to support field observations related to soil disturbance history. All soil samples, excluding samples Mll-B-lb, M15-B- lb, M17-B-2b, M21-B-la, M22-B-la, M22-B-2a, M23-B-la, M23- B-2a, Sl and S3-B-la, were analyzed at Portland State University. Samples analyzed at Portland State University were analyzed with a high-purity Germanium Coaxial Photon Detector System, GE&G ORTEC, and counted for approximately 24 hours. Peak analysis and counting errors were obtained with a EG&G ORTEC 92X Spectrum Master software package. Radionuclide activities and errors were obtained by subtracting (stripping) the natural background of the shielded detector from the raw count. These activities were then compared with the stripped National Bureau of Standards, Standard Reference Material NBS4353 #1, obtained from the Oregon Department of Human Resources, Radiation Laboratory. Samples Mll-B-lb, M15-B-lb, M17-B- 61 2b, M21-B-la, Sl, and S3-B-la were analyzed by Dr. John Meriwether of the University of Southwestern Louisiana, at the Acadiana Research Laboratory in Louisiana. Samples M22-B-la, M22-B-2a, M23-B-la, and M23-B-2a were analyzed by the Oregon Department of Human Resources, Radiation Laboratory. The photopeaks for Th232 , Ac 228 , K40 , Bi. 214 and Cs 137 data used in this study are listed in Table V. The energy and efficiency calibration was checked monthly during the counting periods. Samples representing the lithologic variance observed in this study were analyzed by the Oregon Department of Human Resources, Radiation Laboratory for outside quality assurance and control. Statistical TABLE V RADIONUCLIDE PHOTOPEAKS Decay Isotope Half-life Gamma Energy Relative Intensity of Series (KeV) Photopeak (%) u23a Bi214 19.9 min. 609.3 42.8 1764.5 14.7 10 Th232 Th232 1.41 x 10 yrs. 238.6 43.0 583.1 31. 0 Ac22a 6.13 hr. 911.1 26.4 968. 8 16.3 10 K4o K4o 1.4 x 10 yrs. 1460.8 10.7 Cs137 Cs 137 30 yr. 661.7 85.2 62 analyses of the soil samples follow the procedures outlined in Chase and Rabinowitz (1967) and Friedlander and others (1981) . Soil radionuclide data are presented in two units, Bq/kg and pCi/g, where one Bq equals one nuclear disintegration per second, and Ci equals 3.7 x 1010 Bq. One pCi/g is therefore equal to 37 Bq/kg. All soil radionuclide data are presented initially in Bq/kg. Radionuclide data in the Portland and Salem areas are additionally presented as pCi/g. Radionuclide counting error is presented as +/- Bq/kg in text by +/- percent in Appendix B. The level of confidence for the radionuclide data is 0.05. MAPPING METHODS Soil surveys prepared by the United States Soil Conservation Service provided data on soil composition, profiles, moisture concentration, moist bulk density, permeability, slope and depth to water for much of the study area. Digital geologic data of Oregon (Walker and MacLeod, 1991) , were provided by the United States 63 Geological Survey (USGS, 1993). Portland and Salem area geology maps (Beeson and others, 1989b, 1991; Madin, 1990) were manually digitized at Portland State University utilizing Arc/Info, Geographic Information System software. Digital data of county soil surveys for the Portland area (Green, 1982, 1983; Gerig, 1985) were provided by the Metropolitan Service District (Metro, 1991). Soil data of the Salem area (Williams, 1972; Knezevich, 1982) were manually digitized by the author and incorporated into the data base. Arc/Info was used to analyze soil data and to prepare all the Plates. 64 RESULTS REGIONAL SOIL RADIONUCLIDE GEOCHEMISTRY Gamma spectrometry of 146 soil samples characterizes soils in northwest Oregon with respect to source 22s B. 214 K4o provenance radionuclide activities (AC I 1 I I and T h 2 3 2) . Geoc h emica . 1 in . d 1cat1ons. . o f source provenance are best illustrated with scatter plots of Th and K activities, a technique used successfully by Kadri and others (1983) for identifying geochemical changes in Tertiary formations of northwest Oregon. Kadri and others (1983) found geochemical indicators of changing source provenance between proximal volcanics and plutonic and metamorphic sediments. Four source provenances are primarily responsible for the variability in naturally occurring radionuclides in the study area: 1) oceanic island and rift margin volcanics, 2) proto/modern Cascade arc-volcanics, 3) plutonic and metamorphic sediments, and 4) plateau flood basalts (Figures 14, 15, 16). 800 750 - A 700 650 A <> 600 <> AA A 550 A M 500 A 01 ~A ~ 450 A A 01 <> Ill 400 <>go<> x 350 <> <> <> <> ..,a ~ 300 <>~ <>~ 250 <> ~)8 0 Oo 0 200 - <> ~ 0 <> <> 0 0 0 150 <><>i co 100 <> Oo 50 <> 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Ac228 (Bq/kg) APlutonic and metamorphic sediments oPlateau flood basalts xoceanic and rift margin volcanics <>Proto/modern Cascade volcanics . h . t A 220 K40 1 Fiaure 1__4_.__ Source provenance geoc em1s ry c vs. scatter p ot. °'Ul 800 750 6 700 650 6 <> 600. 6 550 6 500 Ol :::. 450 tr <> <> ill 400 <> <>~<> 350 0 "1' ~ 0 300 o;o( Vo 0 <> od>o 250 --- x 0 0 200. <>000~ <> 0 0 0 150 ~ 0 0 0 0 0 100 <> Cb 50 <> 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Bi 214 (Bq/kg) 6Plutonic and metamorphic sediments oPlateau flood basalts xoceanic and rift margin volcanics <>Proto/modern Cascade volcanics . 214 K4o l Figure 15. S ource provenance geoc h emistry B.1 vs. sea t ter p ot. °' 800 750 l A :::l A 0 600 A 4 A O 550 ~ A A 500 A IA ~ ~ r ,A ~ 450 ~ 0 0 in 400 ~o .0 x 0 0 350 0 0 0 0 ~ r x x :-:ic.: 300 0 ~ o 0 Oo 0 250 d> ~ «°o • o o 0 0 0 0 0 0 2 0 0 <> <> <> 0 ° 0 150 I o T 0 oo 0 100 0 0 00 50 0 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Th232 (Bq/kg) APlutonic and metamorphic sediments oPlateau flood basalts xoceanic and rift margin volcani~s oProto/modern Cascade volcanics F iaure. i 6 . Source provenance geoc h em1stry . Th23 2 vs. K4 o scatter p 1 ot. (j\ -...J 68 Soils developed on oceanic island and rift margin volcanics (Siletz River Volcanics and Tillamook Volcanics respectively) and mafic intrusives (Table VI), typically 232 40 have Th and K activities between 15 and 25 Bq/kg and 228 250 and 375 Bq/kg respectively. Ac activities are slightly higher with activities often between 15 and 35 214 Bq/kg. Bi activities typically range between 20 and 30 Bq/kg. Siletz River Volcanics can be geochemically 228 214 distinguished from Tillamook Volcanics by lower A , Bi , 232 and Th activities. Figures 17, 18, and 19 illustrate Ac 22s , Bi. 214 , and Th232 p l otte d against . K40 activities. . . f or Siletz River Volcanics, Tillamook Volcanics, and mafic intrusives of the Coast Range Province. TABLE VI SOIL RADIONUCLIDE ACTIVITIES (BQ/KG) OF OCEANIC AND OTHER RIFT MARGIN VOLCANICS AND MAFIC INTRUSIVES Tillamook Volcanics * Radionuclide Ac22s Bi214 K4o Th232 # Samples 4 4 4 4 Minimum 13.5 18.4 268.4 15.1 Maximum 32.8 21. 7 377.1 26.6 Average 22.4 20.3 320.8 20.4 Standard deviation (+/- 2 sigma) 7.5 1.2 38.6 4.7 Total error 8.2 3.0 44.5 5.1 69 TABLE VI SOIL RADIONUCLIDE ACTIVITIES (BQ/KG) OF OCEANIC AND OTHER RIFT MARGIN VOLCANICS AND MAFIC INTRUSIVES (continued) Siletz River Volcanics * Radionuclide Ac22s Bi214 K4o Th232 # Samples 2 2 2 2 Minimum 8.9 5.1 143.8 6.2 Maximum 11.4 15.7 157.5 13.8 Average 10.2 10.4 150.7 10.0 Standard deviation (+/- 2 sigma) 1.3 5.3 6.8 3.8 Total error 1. 9 5.3 9.2 4.0 Mafic intrusives * Radionuclide Ac22s Bi 214 K4o Th232 # Samples 2 2 2 2 Minimum 27.0 33.3 248.0 30.2 Maximum 29.7 40.3 258.3 31. 6 Average 28.4 36.8 253.2 30.9 Standard deviation (+/- 2 sigma) 1.4 3.5 5.1 0.7 Total error 3.0 4.2 15.8 0.7 * See Appendix B for samples used. Soils in the Cascade Range (Table VII), developed mainly on basaltic and andesitic volcanics, typically have Th232 activities between 10 to 25 Bq/kg, 15 to 25 Bq/kg for Ac 22s and Bi• 214 , and 200 to 400 Bq I kg for K40 . Th232 activities in basaltic soils are often below 10 Bq/kg, while activities for soils with an andesitic component are commonly above 15 Bq/kg and have been measured up to 24.1 Bq/kg. The highest Th232 and K40 activities are those of undifferentiated ash deposits, all of which are found to 800 750 700 650 600 550 500 ~ ~ 450 ...... _ g 400 - + 0 350 ..,.~ + 300 + + 250 0 0 200 D 150 D 100 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 228 Ac ( Bq/ kg) oSiletz River Volcanics +Tillamook Volcanics oMafic intrusives Figure 17. Soils on Siletz River Volcanics, Tillamook Volcanics and mafic . . o f t h e Range . Ac 228 K40 p 1 intrusives Coast Province vs. scatter ot...... ] 0 800 750 700 650 600 550 500 ~ ~ 450 ...... tJ' co 400 + 0 350 1': ++ 300 + 250 0 0 200 0 150 0 100 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Bi 214 (Bq/kg) oSiletz River Volcanics +Tillamook volcanics oMafic intrusives Figure 18. Soils on Siletz River Volcanics, Tillamook Volcanics and mafic intrusives. . o f t h e Coast Range Province. Bi . 214 vs. K40 scatter p 1 ot...... ] ...-.i 800 750 700 650 600 550 500 ~ ~°' 450 ...... tJ' Pl 400 + 0 350 + ~ 300 + + 250 0 0 200 0 150 0 100 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Th232 (Bq/kg) oSiletz River Volcanics +Tillamook Volcanics oMafic intrusives Figure 19. Soils on Siletz River Volcanics, Tillamook Volcanics and mafic 232 40 intrusives of the Coast Range Province Th vs. K scatter plot...... ] N 73 be above 28 Bq/kg. Of particular interest are samples PS- B-la and P9-B-la. These samples, while derived from the Cascades, have undergone significant weathering and soil development to show a geochemical deviation from less weathered, less developed soil. The effects of weathering and soil pedogenesis on radionuclide behavior in near surf ace environments will be addressed in the discussion section. Figures 20, 21, and 22, derived from Table VII, s h ow Ac 228 , Bi. 214 , and T h232 activities. . . p 1 otte d against . K40 , typical for soils in the Cascades. TABLE VII SOIL RADIONUCLIDE ACTIVITIES (BQ/KG) OF CASCADIAN VOLCANICS Radionuclide Ac22s Bi 214 K4o Th232 # Samples * 56 56 56 52 Minimum 4.5 4.5 53.0 4.0 Maximum 48.4 47.9 660.4 45.9 Average 17.8 19.9 293.9 16.3 Standard deviation (+/- 2 sigma> 8.4 8.1 115.0 8.3 Total error 14.3 12.4 133.0 10.5 * See Appendix B for samples used. 800 750 700 + 650 i 600 -- + 550 soo I + - ~ 450 - + ...... + ++ + g 400 ++ - .,...+ + 0 350 - Ac 228 (Bq/kg) Figure 20. Cascadian soils Ac228 vs. K40 scatter plot. ...... ] .i:::- 800 750 ·- 700 650 + 600 + 550 500 + - J 450 + ...... + + + z 400 + + + ...... + + 0 350 ~ .. + + + 300 ++ + + ++# i'i- ++ + 250 + ++ + ++ * ++ + 200 .p- + + 150 + +++ + 100 + + 50 + 0 ,- ,- ,- ' ' ' 0 5 10 15 20 25 30 35 40 45 50 55 60 Bi214 (Bq/kg) Figure 21. Casca d 1an. soi . l s B. 1 214 vs. K4o scatter p l ot. -..J U1 800 750 ::: l + 600 I + 550 soo I + 01 450 + ~ + + 0. 400 """+ + m "t' + + ~ 350 + + + + + 300 - + -tf- + + + + + + 250 l- +t- ~ + + -t+ + + + + + 200 I + ++ i\- 150 + 1 100 + + 50 t + 0 I I I I I I I I I I I 0 5 10 15 20 25 30 35 40 45 50 55 60 Th232 (Bq/kg) ' C ' 1 h 232 K40 1 Figure 22. asca d.ian soi s T vs. scatter po t . -....] ()) 77 Continuous sediment influx similar in composition to continental igneous and metamorphics of the Idaho Batholith region (Heller and others, 1985), periodically overprinted by local volcanism is recorded throughout Eocene and Oligocene time in western Oregon (Snavely and Wells, 1991). This sediment influx represents the Tertiary marine sediments exposed in the Coast Range, Willamette Valley, and Western Cascades. Radionuclide activities of both source provenances (plutonic/ metamorphic and proximal volcanic) are represented in these Tertiary marine sediments. Table VIII shows comparative. rad. ionuc 1 i. d e activities . . . o f Ac 228 , Bi. 214 , T h232 , and K40 for selected Tertiary marine sediments found in the study area. Sandstones from the Tyee and Cowlitz formations and sandy siltstones of the Keasey Formation have Th232 activities largely indicative of granitic and metamorphic sources. Silty clay samples collected from Proto Cascade volcanics (Yamhill Formation) are lower in both K40 and Th232 and reflect more mafic sources. Caldwell (1993) noted similar geochemisty findings from the Yamhill 78 TABLE VIII SOIL RADIONUCLIDE ACTIVITIES (BQ/KG) OF SELECTED TERTIARY MARINE SEDIMENTS Tyee Formation * Radionuclide Ac22a Bi 214 K4o Th232 # Samples 2 2 2 2 Minimum 32.8 26.9 376.4 33.7 Maximum 34.8 33.6 491.9 34.3 Average 33.8 29.9 434.2 34.0 Standard deviation (+/- 2 sigma) 1.0 3.1 57.8 0.3 Total error 3.3 3.9 60.4 1. 6 Cowlitz Formation * Radionuclide Ac22a Bi 214 K4o Th232 # Samples 6 6 6 6 Minimum 28.0 18.2 352.9 26.7 Maximum 38.5 51. 7 494.0 37.7 Average 33.5 36.5 434.8 32.4 Standard deviation (+/- 2 sigma) 3.7 12.0 49.6 3.9 Total error 7.0 13.7 61. 3 5.4 Keasey Formation * Radionuclide Ac22a Bi 214 K4o Th232 # Samples 4 4 4 4 Minimum 26.8 41. 0 485.2 28.3 Maximum 38.3 42.6 623.3 34.3 Average 31. 3 41. 7 554.8 30.2 Standard deviation (+/- 2 sigmal 4.3 0.7 56.3 2.4 Total error 6.2 4.0 65.6 3.7 Yamhill Formation * Radionuclide Ac22a Bi 214 K4o Th232 # Samples 2 2 2 2 Minimum 25.9 21. 4 222.4 16.8 Maximum 26.9 23.2 242.5 19.8 Average 26.4 22.3 232.4 18.3 Standard deviation (+/- 2 sigma> 0.5 0.9 10.1 1. 5 Total error 2.2 2.1 15.2 2.1 79 TABLE VIII SOIL RADIONUCLIDE ACTIVITIES (BQ/KG) OF SELECTED TERTIARY MARINE SEDIMENTS (continued} Pittsburg Bluff Formation * Radionuclide Ac22s Bi 214 K4o Th232 # Samples 2 2 2 2 Minimum 36.0 46.5 206.6 34.4 Maximum 39.3 55.8 373.1 36.9 Average 37.6 51. 2 289.8 35.6 Standard deviation {+/- 2 sigma) 1. 6 4.6 83.2 1. 2 Total error 3.7 5.3 84.2 2.3 * See Appendix B for samples used. Formation and considered the source to be partially derived from proximal volcanism. Tuffaceous samples from the Pittsburg Bluff Formation are low in K40 and 232 relatively high in Th and may repersent mixing of proximal volcanics with plutonic and metamorphic sediments. Figures 23 and 24 show the geochemical variations' ' o f A c 228 and B.1 214 t o K40 rad. 1onuc 1.1 d e act1v1t1es . . ' for Tertiary marine sediment, including the Tyee, Cowlitz, Keasey, Yamhill, Pittsburg Bluff and Astoria formations. Figure 25 shows additional Th and K data of Kadri and others (1983) and Caldwell (1993). 800 750 700 650 0 x 600 x 550 x 500 x +o+ .B1 450 -- + ...... _ + p:iO' 400 + - 0 A 0 350 + ~ 300 250 t 0 0 200 I A 150 100 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Ac22a (Bq/kg) +Cowlitz Fm. XKeasey Fm. APittsburg Bluff Fm. oTyee Fm. oYamhill Fm. 228 40 Figure 23. Soils on Tertiary marine sediment Ac vs. K ~catterplot. CD 0 800 750 700 650 x 600 x 550 x 500 ~ <> + x + ~ 450 + '-- 01 r:q 40 0 + + <> 6 0 350 "':' + ~ 300 250 0 0 200 6 150 100 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Bi 214 (Bq/kg) +Cowlitz Fm. xKeasey Fm. 6Pittsburg Bluff Fm. oTyee Fm. oYamhill Fm. Figure 24. 801. 1 s on T ert1ary . marine. se d.iment B i. 214 vs. K 40 scatter p 1 ot. CD j-1 900 850 800 Ii Ii 750 700 650 'O Ii 600 • Ol 550 +. ~ 500 ...... - • tr ~ p:i 450 - Ii • 400 *~ + 0 • • + 0 "'::.::: 350 • + + • * * 300 Ii * • 250 a xx• • * * 200 a •JC a 150 * 100 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 Th232 (Bq/kg) :ecAstoria Fm. (Kadri and Others, 1983) +Pittsburg Bluff Fm. (Kadri and Other, 1983) •Cowlitz Fm. JiSpencer Fm. (Caldwell, 1993) eCowlitz Fm. (Kadri and Others, 1983) oTyee Fm. -Keasey Fm. XYamhill Fm. aKeasey Fm. (Kadri and Others, 1983) •Yamhill Fm. (Caldwell, 1993) ePittsburg Bluff Fm. Figure 25. Soils on Tertiary marine sediment Th 232 vs. K40 scatter plot. CX> N 83 Quaternary sediments composed of continental igneous and metamorphics are largely derived from the Columbia River Basin drainage system. Throughout the Willamette Valley Province, Missoula Flood sediments constitute much of the sediments at elevations of 130 meters and less. Activities of 29.3 to 40.0 Bq/kg, 30.3 to 50.3 Bq/kg, 428.9 to 758.5 Bq I kg, and 26.8 to 39.0 Bq I kg and for Ac 228 , Bi.214 , K40 , and Th232 respectively,. are observed for both coarse (Qfc) and fine-grained (Qff) Missoula Flood sediment f acies (Table IX) . Missoula Flood sediment radionuclide activities relative to grainsize is . . f 228 Bi 214 inconclusive. However, t h e activity ranges o Ac , I 40 232 K , and Th are slightly higher in the fine-grained facies. Additional sampling of Missoula Flood facies needs to be done in order to determine if this observation is real or not. Portland Hills silt deposits, primarily loess, found at elevations above 90 meters on the Tualatin Mountains 228 . 214 40 232 (Beeson and others, 1991 ) , have Ac , Bi , K and Th activities of 28.6 to 36.8 Bq/kg, 32.5 to 42.0 Bq/kg, 84 TABLE IX SOIL RADIONUCLIDE ACTIVITIES {BQ/KG) OF MISSOULA FLOOD SEDIMENTS Missoula Flood sediment {Qff)* Radionuclide Ac22s Bi 214 K4o Th232 # Samples 11 11 11 11 Minimum 30.9 30.3 429.0 28.8 Maximum 42.0 50.3 758.5 39.0 Average 36.0 38.2 545.2 33.2 Standard deviation <+/- 2 sigma) 3.9 5.3 89.9 3.0 Total error 10.9 8.6 106.7 6.5 Missoula Flood sediment {Qfc)* Radionuclide Ac22s Bi 214 K4o Th232 # Samples 4 4 4 4 Minimum 29.3 33.7 434.1 26.8 Maximum 40.0 43.7 583.5 34.1 Average 34.8 38.5 498.0 30.7 Standard deviation <+/- 2 sigma) 4.4 4.0 54.7 2.7 Total error 5.9 5.2 60.1 3.7 * See Appendix B for samples used. 427.9 to 525.6 Bq/kg, and 30.0 to 32.7 Bq/kg respectively (Table X) . Both the Portland Hills silt deposits and Missoula Flood sediments overlap significantly in their geochemistry. (Figures 26, 27 and 28). Similarly, samples from a fine-grained facies of the Troutdale Formation (Pl3-B-la and Pl7-B-la), overlap in radionuclide chemistry. The author considers Missoula Flood sediment, 800 750 + 700 0l_JO + P17-B-la 600 ++A x 550 + +o 6 o 500 + x ~ 0 X Pl3-B-lt J 450 XoO+ ++ -----g 400 -·- 350 "~ 300 250 200 150 100 50 0 - 0 5 10 15 20 25 30 35 40 45 50 55 60 Ac 228 (Bq/kg) + Missoula Flood fine-grained o Portland Hills silt x Missoula Flood coarse-grained 6 Troutdale Formation Figure 26. Soils on Missoula Flood sediment and Portland Hills silt 228 40 Ac vs. K scatter plot. Troutdale Fm. (Pl3-B-la and P17-B-la). (X) Ul ------·------~------800 750 + 700 650 + 600 + x6 P17-B-la + + 550 P13-B-la + <> <> 500 + t x ~ "ir>.r r 450 + <>XO 01 400 -~ 350 "'~ 300 250 200 150 100 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 214 Bi ( Bq I kg ) + Missoula Flood fine-grained <> Portland Hills silt X Missoula Flood coarse-grained 6 Troutdale Formation Figure 27. Soils on Missoula Flood sediment and Portland Hills silt Bi• 214 vs. K40 scatter plot. Troutdale Fm. ( Pl3-B-la an d Pl7-B-la ) . 00 O'\ 800 750 + 700 650 + 600 fl. Pl7-B-la r:;so ++ * + + ~ g P13-B-la ~00 ~ ~ x ~ 450 <> ++ ....___ > + Missoula Flood fine-grained <>Portland Hills silt x Missoula Flood coarse-grained 6 Troutdale Formation Figure 28. Soils on Missoula Flood sediment and Portland Hills silt 232 40 Th vs. K scatter plot. Troutdale Fm. (Pl3-B-la and P17-B-la). CX> ....J 88 Portland Hills silt, and parts of the Troutdale Formation . f h . 1 228 Bi 214 40 to b e representative o t e typica Ac , I K and 232 Th activities derived from the Columbia River drainage basin. TABLE X SOIL RADIONUCLIDE ACTIVITIES (BQ/KG) OF PORTLAND HILLS SILT (LOESS) Radionuclide Ac22a Bi214 K4o Th232 # Samples 5 5 5 5 Minimum 28.6 32.5 427.9 30.0 Maximum 36.8 42.0 525.6 32.7 Average 32.1 36.7 471.8 30.9 Standard deviation <+!- 2 sigmal 2.7 3.7 41. 9 1.0 Total error 5.3 5.3 49.4 3.2 * See Appendix B for samples used. The bulk of the remaining sedimentation west of the Cascades, is derived from the erosion of local highlands. Except for a few fault blocks and antiforms composed of Tertiary marine sediments and flood basalts in the Willamette Valley, sediments on active flood plains typica· ll y re fl ect Ac 22a , B.214i , K4o an d T h232 activities... indicative of Cascade Range volcanic soils {Table XI) . 89 The influence of Tertiary marine sedimentary rocks derived from plutonic and metamorphic sources on Willamette River sediment radionuclide activities is not apparent other than slightly higher K activities than those typically associated with Cascade volcanics. TABLE XI SOIL RADIONUCLIDE ACTIVITIES (BQ/KG} OF HOLOCENE FLOOD PLAIN SEDIMENT Willamette River sediment * Radionuclide Ac22a Bi 214 K4o Th232 # Samples 8 8 8 8 Minimum 13 15.7 252.9 14.6 Maximum 27.5 34.6 426.0 26.1 Average 20.3 21. 0 341. 3 18.1 Standard deviation (+/- 2 sigmal 4.8 5.7 59.6 4.7 Total error 7.2 6.7 67.7 5.4 Mixed Columbia River/Willamette River sediment * 228 214 40 Radionuclide Ac Bi K Th232 # Samples 1 1 1 1 Pl4-C-la 23.7 24.9 497.3 21. 2 Counting error 10.8 1.2 37.5 0.5 Clackamas River sediment * Radionuclide Ac22a Bi214 K4o Th232 # Samples 1 1 1 1 Pll-C-la 12.9 15.7 212.3 11.6 Counting error 10.8 0.9 29.7 0.4 90 TABLE XI SOIL RADIONUCLIDE ACTIVITIES (BQ/KG) OF HOLOCENE FLOOD PLAIN SEDIMENT (continued) Cascadian Volcanics * Radionuclide Ac22a Bi 214 K4o Th232 # Samples 56 56 56 56 Minimum 40.5 4.5 53.0 4.0 Maximum 48.4 47.9 660.4 45.9 Average 17.8 19.9 293.9 16.3 Standard deviation <+!- 2 sigma> 8.4 8.1 115.0 8.3 Total error 14.3 12.4 133.0 10.5 Undifferentiated Missoula Flood sediment * Radionuclide Ac22a Bi 214 K4o Th232 # Samples 16 16 16 16 Minimum 29.3 30.3 429.0 26.8 Maximum 42.0 50.3 758.5 39.0 Average 35.7 38.3 533.4 32.6 Standard deviation (+/- 2 sigma) 4.1 5.0 85.0 3.1 Total error 10.8 7.6 62.1 5.9 * See Appendix B for samples used. The effects of mixing Columbia River Basin drainage system sediments with Coast Range and Cascade Range sediments is best observed in sample P14-C-la, located along the confluence of the Columbia and Willamette River 40 (Figure, 11). The K activity of this sample is typically higher than activities associated with Cascade volcanics, but not necessarily that of the Coast Range. 91 Samples from Willamette River sediments, show K40 activities below that capable of producing values observed 232 in sample Pl4-C-la. The Th activity in Pl4-C-la is 232 approximately 10 Bq/kg lower than average Th (31.9 +/- 2.9 Bq/kg) activities for undifferentiated Missoula Flood 232 sediments. Th activity is well within the activity range associated with Cascade volcanics. Volcanic airf all ash and water laid mixed ash and tuff geochemistry east of the Cascades is quite varied (Table XII) . Volcanic airfall ash deposits analyzed show h ig. h er Ac 22a , Bi• 214 , K4o and Th232 activities. . . t h an t h ose associated with soils developed on water laid and mixed ash and tuff deposits. Mixing with more mafic materials during stream transport can easily account for the more mafic signature (lower radionuclide activities) exhibited in a few of the water laid deposits. 92 TABLE XII SOIL RADIONUCLIDE ACTIVITIES (BQ/KG} OF CASCADIAN VOLCANIC ASH, AND WATER LAID MIXED ASH AND TUFF Cascadian air fall volcanic ash * Radionuclides Ac22s Bi214 K4o Th232 # Samples 4 4 4 4 Minimum 24.1 25.3 378.1 19.9 Maximum 48.4 47.9 660.4 45.9 Average 37.l 36.2 514.4 33.4 Standard deviation (+/- 2 sigma) 10.4 9.5 120.6 10.8 Total error 15.9 9.7 125.4 14.4 Water laid mixed ash and tuf f * Radionuclides Ac22s Bi214 K4o Th232 # Samples 12 12 12 12 Minimum 10.4 13.0 265.8 10.8 Maximum 27.9 31. 0 445.4 26.2 Average 18.5 21. 7 358.5 16.8 Standard deviation (+/- 2 sigma> 6.2 5.1 55.6 5.1 Total error 8.0 6.8 66.2 6.0 * See Appendix B for samples used. 232 40 In this study, Th : K ratios were used to help determine source origin and soil development history. 23 2 4 0 . . 1 . h . d . 1 T h :K ratio groupings, re ative to weat ering an soi development stages, are largely based on available soil data provided by United States Department of Agriculture Soil Conservation Service and Forest Service soil surveys for northwest Oregon. Where not available, the 93 interpretation of local weathering and soil development stages were estimated by the author. One of the best areas in the study area to observe 2 3 2 4 0 soi. 1 d eve 1 opment re 1 ative . to Th :K ratios. is . a 1 ong t h e terraces of the Clackamas River (Figure 29) . These terraces are primarily composed of Cascadian volcanics. The five Clackamas River terraces selected (Tl, T2, T4, TS-1 and TS-2) for this study show some variation in Th232 and K40 activities, but they clearly illustrate how T h 2 3 2 :K 4 0 ratios. c h ange wit . h weat h ering . an d soi . 1 pedogenesis (Table XIII). Site Pll (the youngest terrace, Tl), has a Th232 :K40 ratio of 0.05 and fits well within the range of Entisols in this study (Table XIV) . An A/Bw/C pedologic horizon at site Pl2 (T2) and A/Bt pedologic horizons at sites PlO (T4), P9 (TS-1) and PS (TS-2) (Figure 29) reflect a progression in soil development stages (Entisol --> Inceptisol --> Alfisol, --> Ultisol). Th232 :K40 ratios• for terraces T2, T4, TS-1, TS-2 progressively increase from 0.05, 0.11, 0.29, and 0.33 respectively. A similar ratio trend related to weathering . l d . · A 22 a . d f h23 2 . h 4 o and soi pe ogenesis using c instea o T wit K 94 ·11011~1· I ,.. .<'.-Ci "'1.... ••. 46 , FIRWOOO ~.Rid){t; I \ "'""'"r • ...,...- L. ):- .,_.~ \• I \-,6,- 45 i ( ! 3 i5 i' 4il ~ I I j _, ,~~o q ·r ,- BM - 1-.-._ ·.. <·, \''' ----- )' b~ ~-\ ,-J.--- t-'.. --1 ·"'o Feldhe11Y1er f't'.vi :, ',\ t. t~' < o"-.. \ . 1s'1f ·', \-. I , :-.\ ~,:.o. . 1 43 ~ ~ ~~-= ;_.,:---- \ ~-- -~~ \ / . ';~ T2 o"'°- .-·,, .• \ fl - l.~4-'\ <>, ~-!· Pl2 ~ 0 I,. ':-:;~:r.. 64 sBB···-'" : Tra • ----~=-= 22\ r.: : 63 g ~ 0 ~" __:i2.-: .~ T Terraces p Sites • ~ 38 . ~. QUADRANGLE8 LOCATION ~ 1 t 0 l SCALE 1:62500 2 3 4 MILES E~F=l ~ -=--======i======~E=====~======:::::J 3000 O 3000 6000 9000 12000 15000 18000 21000 FEET ~~-==r====r E+3 F:--:3 ~ F ., F===r=::=F==3 F"""=3 a E:::::::3 l 5 O I 2 3 4 5 KILOMETERS s:::I:m..EL:EJ r===?7 E CONTOUR INTERVAL 40 FEET DOTTED UNE.S REPRESENT 20 FOOT CONTOURS DATUM IS MEAN SEA LEVEL Figure 29. River terraces and sample locations along the Clackamas River. 95 was found in the Quachita and Mississippi River drainage systems of Louisiana (Table XV) (Data: Meriwether and others, 1992). TABLE XIII RADIONUCLIDE ACTIVITIES (BQ/KG) AND RATIOS OF THE CLACKAMAS RIVER TERRACES Terrace Elev (m) Stage Ac22s Bi2H K4o Th232 Ac22s: K40 Bi 214: K4o Th232: K4o Relative age (yrs.) Tl 76.2 A/C 12.9 15.7 212.3 11.6 0.06 0.07 0.05 < 100 T2 117.4 A/Bw/C 13.2 17.0 265.7 14.7 0.05 0.06 0.06 ? T4 207.3 A/Bt/C 24.0 25.9 227.3 24.3 0.11 0.11 0.11 ? T5-1 262.2 A/Bt/C 25.5 28.8 87.9 25.2 0.29 0.33 0.29 200,000 * T5-2 268.3 A/Bt/C 17.3 18.6 53.0 17.5 0.33 0.35 0.33 200,000 * * (Based on estimates from Reckendorf, 1993) TABLE XIV 232 40 TH : K ACTIVITY RATIOS OF ENTISOLS IN THE STUDY AREA 232 40 Sample Th : K Ratio Location M3-B-la 0.03 Welches M3-B-2a 0.03 Welches Pll-C-la 0.05 Clackamas River (Tl) (Eagle Creek) P14-C-la 0.04 Columbia and Willamette Rivers (North Portland) S7-B-la 0.04 Salem S7-B-lb 0.04 Salem S9-B-la 0.04 Salem S9-B-lb 0.04 Salem 96 TABLE XV 228 40 AC :K ACTIVITY RATIOS FOR THE QUACHITA/MISSISSIPPI RIVER DRAINAGE SYSTEMS Geology Ac22a K4o Ac22a: K4o Estimate age (yrs.) Qal 40 637 0.06 < 11,000 Qal 55 498 0.11 < 11,000 Qbsl 48 498 0.10 Qbs 50 497 0.10 Qnl 58 602 0.10 Qtd 36 359 0.10 11,000 QTpl 37 301 0.12 QTp 29 207 0.14 30,000 QTi 29 125 0.23 > 30,000 (Data from Meriwether and others, 1992). It is not clear how mobile Th232 is on these terraces. 232 40 However, Th is much less mobile than K under the conditions for which these horizons have responded. Assuming that initial K for these terrace sediments falls within the 200 to 350 Bq/kg range typically associated with Cascadian volcanics, those soils with K40 values between 50 and 100 Bq I kg would suggest K40 loss to be between 50 percent and 86 percent respectively. Higher 232 Th observed on terrace T5-2, compared with terrace Tl, is assumed to be accumulation from weathering and soil 97 232 pedogenic processes. Consequently, Th accumulation for soils in the immediate vicinity of site P8 is probably no higher than 20 percent above initial concentrations. Ultisols in the study area show some variation in radionuclide activities (Table XVI) . Ultisols in the Eola Hills and Salem Hills areas, developed on the Grande Ronde flows of Columbia River basalt, average 151.8 +/- 78.8 Bq/kg and 113.6 +/- 10 Bq/kg K respectively. In contrast to Ultisols developed on Grande Ronde flows of Columbia River basalt in the Eola Hills area, Inceptisols (developed on Grande Ronde flows of Columbia River basalt) 232 show Th activities approximately 15 to 20 percent less (Table XVII) . Ultisols developed on Grande Ronde flows TABLE XVI RADIONUCLIDE ACTIVITIES (BQ/KG) OF ULTISOLS Eola Hills * Radionuclide Ac22s Bi 214 K4o Th232 # Samples 2 2 2 2 Minimum 35.2 28.3 151.8 34.5 Maximum 38.3 40.2 154.7 35.8 Average 37.8 34.2 153.2 35.1 Standard deviation (+/- 2 sigma) 1. 6 5.9 1. 5 0.7 Total error 1. 7 35.3 6.2 1. 2 98 TABLE XVI RADIONUCLIDE ACTIVITIES (BQ/KG) OF ULTISOLS (continued) Salem Hills * Radionuclide Ac22a Bi 214 K4o Th232 # Samples 4 4 4 4 Minimum 27.6 27.4 88.3 27.8 Maximum 30.0 31.1 140.6 30.1 Average 28.6 29.8 113.6 29.0 Standard deviation (+/- 2 sigma> 0.9 1.4 22.2 0.9 Total error 4.3 3.1 101. 7 2.2 Parrett Mountain * Radionuclide Ac22a Bi 214 K4o Th232 # Samples 2 2 2 2 Minimum 29.4 34.2 222.3 30.8 Maximum 31. 0 35.2 315.1 31. 0 Average 30.2 34.7 268.7 30.9 Standard deviation (+/- 2 sigma) 0.8 0.5 46.4 0.1 Total error 4.3 2.9 51. 7 1. 7 Siletz River Volcanics * Radionuclide Ac22a Bi214 K4o Th232 # Samples 2 2 2 2 Minimum 8.9 5.1 143.8 6.2 Maximum 11.4 15.7 157.5 13.8 Average 10.2 10.4 159.7 10.0 Standard deviation (+/- 2 sigma) 1. 3 5.3 6.8 3.8 Total error 1. 9 5.3 9.2 4.0 Portland area Boring Lava* Radionuclide Ac22a Bi 214 K4o Th232 # Samples 1 1 1 1 Activity 30.9 36.7 311.9 32.8 Counting error 2.1 1. 7 10.8 1.1 99 TABLE XVI RADIONUCLIDE ACTIVITIES (BQ/KG) OF ULTISOLS (continued) Banks Columbia River basalt * Radionuclide Ac22s Bi 214 K4o Th232 # Samples 2 2 2 2 Minimum 45.8 47.0 208.2 43.3 Maximum 47.6 52.7 313.4 49.3 Average 46.7 49.9 260.8 46.3 Standard deviation <+!- 2 sigmal 0.9 2.9 52.6 3.0 Total error 3.6 4.1 54.2 3.5 TABLE XVII RADIONUCLIDE ACTIVITIES (BQ/KG) OF COLUMBIA RIVER BASALT INCEPTISOLS ON THE EOLA HILLS Radionuclide Ac22s Bi 214 K4o Th232 # Samples * 5 5 5 4 Minimum 26.5 21.1 155.9 25.0 Maximum 33.3 30.7 289.6 27.6 Average 29.3 26.0 232.9 26.3 Standard deviation <+/- 2 sigmal 2.8 3.7 51. 5 1.1 Total error 4.4 4.3 53.2 6.0 * See Appendix B for samples used. o f Parrett Mountain. s h ow s1m1 . . 1 ar Ac 228 , Bi. 214 , K40 T h232 activities as Ultisols developed on Grande Ronde flows of the Eola Hills to the south. 100 Near Banks, Oregon, an Ultisol (developed on Columbia River basalt, but flow(s) not identified), averaged 40 approximately 260 +/- 62 Bq/kg K (Table XVI). Of particu. 1 ar interest . is. t h e anoma 1 ous 1 y h.ig h Ac 228 , Bi. 214 and 232 . . . . h. Ul . l 220 B. 214 d h232 T h activities in t is tiso . Ac , 1 an T were approximately 90 percent higher than Ultisols analyzed from the Eola Hills and Salem Hills to the south. Ultisols developed on Siletz River Volcanics average 150.7 + I - 6.8 Bq I kg K40 and 10.0 + I - 4.0 Bq I kg Th232 (Table XVI) . These Ultisols are distinguished from those developed on Portland area Boring Lava and Columbia River 232 40 Basalt by lower Th and somewhat lower K . The one Boring Lava sample (Pl8-B-la) was geochemically indistinguishable from Columbia River basalt samples on 40 Parrett Mountain. However, on the basis of K , the Boring Lava sample could be distinguished from those of the Eola Hills and Salem Hills Ultisols. Figure 30 shows 2 3 2 4 0 T h p 1 otte d against . K f or S 1. 1 etz River . Vo 1 canics, . Columbia River basalt, and Boring Lava Ultisols. Figures 31 and 32 illustrate similar radionuclide activity pat t erns wit. h Ac 228 and Bi . 214 . 800 750 700 650 600 550 500 ~ .-81 450 ....__ O' 40 0 -r:Q 350 ··~ 300 ~ <> 250 <> 200 <> 150 + <> + ~ 100 <>o 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Ac 232 (Bq/kg) +Siletz River Volcanics XBoring Lava ()Columbia River basalt Figure 30. Ultisols on Siletz River Volcanics, Columbia River basalt and Boring. Lava Ac 228 vs. K40 scatter plot. 1---1 0 1---1 ------·--.-- 800 750 700 650 600 550 - 500 r 450 '- p:itJ' 400 350 ""~ <> x 300 <> 250 <> 200 <> 150 + <> + o<> 100 ~ 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Bi 214 (Bq/kg) +Siletz River Volcanics XBoring Lava <>Columbia River basalt Figure 31. Ultisols on Siletz River Volcanics, Columbia River basalt . . 214 40 1 an d B or1ng Lava Bi vs. K scatter p ot. t-1 0 N ------·--·--·-- 800 750 700 650 600 550 soo - .B1 450 ----tJ1 p'.l 400 350 ~ x 300 <> <> 250 <> 200 <> 150 + <> + o<> 100 <>o 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Th 232 (Bq/kg) +Siletz River Volcanics XBoring Lava ()Columbia River basalt Figure 32. Ultisols on Siletz River Volcanics, Columbia River basalt and Boring. Lava Th 232 vs. K40 scatter plot. t-l 0 VJ ------~ 104 With the exception of sample C16-B-la, all B horizons analyzed from Ultisols developed on Siletz River Volcanics, Boring Lava and Columbia River basalt have 232 40 . Th :K ratios equal to or greater than 0.10 (Table XVIII). Many have ratios greater than 0.12. TABLE XVIII RADIONUCLIDE ACTIVITIES (BQ/KG) AND RATIOS OF ULTISOLS Eola Hills (Columbia River basalt) Radionuclides Radionuclide Ratios Sample Ac22s Bi214 K4o Th232 Ac22s : K4o Bi 214 : K4o Th232: K4o S6-B-la 35.2 28.3 151.8 34.5 0.23 0.19 0.23 S6-B-lb 38.3 40.2 154.7 35.8 0.23 0.26 0.25 Salem Hills (Columbia River Basalt) Radionuclides Radionuclide Ratios Sample Ac22s Bi 214 K4o Th232 Ac22s: K4o Bi 214: K4o Th232: K4o SlO-B-la 28.1 27.4 129.9 27.8 0.22 0.21 0.21 S10-B-2a 27.6 30.2 140.6 28.6 0.20 0.21 0.20 Sll-B-la 28.7 30.6 95.5 29.5 0.30 0.32 0.31 Sll-B-2a 30.0 31.1 88.3 30.1 0.34 0.35 0.34 Parrett Mountain (Columbia River Basalt) Radionuclides Radionuclide Ratios Sample Ac22s Bi 214 K4o Th232 Ac22s: K4o Bi 214: K4o Th232: K4o W7-B-la 29.4 30.8 222.3 35.2 0.13 0.14 0.16 W8-B-la 31. 0 31. 0 315.1 34.2 0.10 0.10 0.11 Philomath (Siletz River Volcanics) Radionuclides Radionuclide Ratios Sample Ac22s Bi 214 K4o Th232 Ac22s: K4o Bi 214: K4o Th232: K4o C13-B-la 11. 4 13.8 143.8 15.7 0.08 0.10 0.11 C16-B-la 8.9 6.2 157.5 5.1 0.06 0.04 0.03 105 TABLE XVIII RADIONUCLIDE ACTIVITIES (BQ/KG) AND RATIOS OF ULTISOLS (continued) Portland area (Boring Lava) Radionuclides Radionuclide Ratios Sample Ac22a Bi 214 K4o Th232 Ac22a: K4o Bi 214: K4o Th232: K4o P18-B-la 30. 9 32. 8 331. 9 36. 7 0.09 0.10 0.11 Banks (Columbia River Basalt) Radionuclides Radionuclide Ratios Sample Ac22a Bi 214 K4o Th232 Ac22a: K4o Bi 214: K4o Th232: K4o C3-B-la 45.8 43.3 313.4 47.0 0.15 0.14 0.15 C3-B-2a 47.6 9.3 208.2 52.7 0.23 0.24 0.25 Radionuclide variability between soil horizons tested at sites P16, P17 and C13, C14, C15, W7 and W8 show how A, B, and C soil horizons vary in terms of radionuclide activities (Table XIX) . Eight of the nine profiles 232 analyzed show higher Th activities in the B horizon than 228 the overlying A and underlying C horizons. However, Ac andi or Bi. 214 , and K4o act1v1t1es. . . were not necessar1· l y higher in the B horizons. Three of the nine profiles show 214 maximum Bi activities in the B horizon and five show 214 maximum Bi activities in the A horizon. One of the four profiles where C horizons are included shows the highest 106 Bi 214 activity in the C horizon. Four of the nine profiles show maximum Ac228 activities in the A horizon and one of the four profiles where C horizons are included shows the highest Ac228 activity in the C horizon. Three of the nine profiles show maximum K40 activities in the B horizon and two of the four profiles where C horizons are included show maximum K40 activities in the C horizon. Deviation from the expected accumulation in the B horizons (Asher- Bolinder and others, 1990; Burns and others, 1991}, particularly with K40 in the A horizon at sites W7 and W8, may be the result of agricultural contamination from fertilizers containing potassium. TABLE XIX RADIONUCLIDE ACTIVITY (BQ/KG} VARIABILITY BETWEEN SOIL HORIZONS Portland Hills loess (site P16) Radionuclides Radionuclide Ratios Samples Horizon Ac22a Bi 214 K4o Th232 Ac22a: Th232 Bi214: K4o Th232: K4o P16-A-la A 26.9 29.6 438.3 29.1 0.06 0.07 0.07 P16-B-la B 31. 0 32.0 427.9 30.2 0.07 0.07 0.07 P16-C-la c 30.3 30.1 423.7 30.0 0.07 0.07 0.07 Columbia River Drainage Basin System Troutdale Formation (site Pl 7) Radionuclides Radionuclide Ratios Samples Horizon Ac22a Bi214 K4o Th232 Ac22a: Th232 Bi 214: K4o Th232: K4o Pl7-A-la A 34.9 42.3 573.7 34.2 0.06 0.07 0.06 Pl7-B-la B 34.9 44.6 593.5 44.2 0.06 0.08 0.07 Pl7-C-la c 39.4 45.4 535.1 38.8 0.07 0.08 0.07 107 TABLE XIX RADIONUCLIDE ACTIVITIES (BQ/KG) VARIABILITY BETWEEN SOIL HORIZONS (continued) Columbia River Basalt (Grande Ronde flow} (site W7} Radionuclides Radionuclide Ratios Samples Horizon Ac220 Bi214 K4o Th232 Ac220: Th232 Bi 214: K4o Th232: K4o W7-A-la A 37.3 39.0 309.1 29.7 0.12 0.13 0.10 W7-B-la B 29.4 35.2 222.3 30.8 0.13 0.16 0.14 Columbia River Basalt (Grande Ronde flow} (site W7} Radionuclides Radionuclide Ratios Samples Horizon Ac220 Bi214 K4o Th232 Ac22s: Th232 Bi214: K4o Th232: K4o W8-A-la A 30.6 35.0 382.6 29.2 0.08 0.09 0.08 W8-B-la B 31. 0 34.2 315.1 31 0.10 0.11 0.10 Missoula Flood sediments (fine-grained) (site W9} Radionuclides Radionuclide Ratios 228 214 40 232 Samples Horizon Ac Bi K Th Ac220: Th232 Bi 214: K4o Th232: K4o W9-A-la A 34.2 40.5 587.8 32.2 0.06 0.07 0.05 W9-B-la B 33.2 37.7 567.7 34.3 0.06 0.07 0.06 Siletz River Volcanics (site Cl3) Radionuclides Radionuclide Ratios 228 Samples Horizon Ac Bi214 K4o Th232 Ac220: Th232 Bi 214: K4o Th232: K4o C13-A-la A 14 .1 17.9 114.7 12.7 0.12 0.16 0.11 C13-B-la B 11. 4 15.7 143.8 13. 8 0.08 0.11 0.10 Siletz River Volcanics (site Cl6) Radionuclides Radionuclide Ratios 228 214 40 Samples Horizon Ac Bi K Th232 Ac220: Th232 Bi 214: K4o Th232: K4o C16-A-la A 16.0 16.0 169 17.4 0.09 0.09 0.10 Cl6-B-la B 8.9 5.1 157.5 6.2 0.06 0.03 0.04 Cl6-C-la C 7.6 6.2 230.3 5.9 0.03 0.03 0.03 Tyee Formation (site Cl4) Radionuclides Radionuclide Ratios 228 214 40 232 Samples Horizon Ac Bi K Th Ac220: Th232 Bi 214: K4o Th232: K4o Cl4-A-la A 26.4 31.8 475.3 26.6 0.06 0.07 0.06 Cl4-B-la B 34.8 33.0 491.9 34.3 0.07 0.07 0.07 108 TABLE XIX RADIONUCLIDE ACTIVITIES (BQ/KG) VARIABILITY BETWEEN SOIL HORIZONS (continued) Tyee Formation (site C15) Radionuclides Radionuclide Ratios Samples Horizon Ac22a Bi214 K4o Th232 Ac22a: Th232 Bi 214: K4o Th232: K4o ClS-A-la A 28.4 26.0 454.8 29.3 0.06 0.06 0.06 ClS-B-la B 32.8 26.9 376.4 33.7 0.09 0.07 0.09 ClS-C-la C 29.4 22.7 656.2 29.7 0.04 0.03 0.05 PORTLAND AND SALEM SOIL RADIONUCLIDE GEOCHEMISTRY Portland and Salem Ac 228 , Bi. 214 , K40 and Th232 activities reflect Columbia River drainage basin and Willamette Valley source provinces activities. Radionuclide activities on active flood plains reflect activities characteristic of the Cascades and Coast Range, while terraces above active flood surfaces reflect activities characteristic of the Columbia River drainage basin. Areas within Portland and Salem known to have elevated indoor radon (Toombs, 1985; the Oregon Department of Human Resources, Health Division, 1994) (Appendix C), are not identified by soil and/or surface Bi214 activities 109 (Figures 33 and 34}. Correlation coefficients of r = -0.32 (not significant at the 0.05 confidence level) and r = -0.53 (not significant at the 0.05 confidence level), b etween soi. 1 Bi . 214 activity. • an d in . d oar Rn 222 read. ings f or Portland and Salem respectively support the spatial data represented in Figures 33 and 34 that soil Bi214 activity is not directly responsible for elevated indoor radon in these areas (Table XX) . '. 110 'i ! ~ ; j P o r t I a n d S o chemistry Port I and j ndoor radon I eve Is f 121• 523a IZ2• 30 00 L e 9.e n ,,. :f73Q 45• 3730 Port I and 1s o chemistry B i - 2 1 4 a c t i v i t YI I e s s t h a n 0 . 6 8 p C i I g ( 2 5 B q I k g ) - Bi-214 activity! greater than 0.68 pCi/g (25 Bq/kg) P o r t I a n d I i n d o o r r a d o n I e v e I s D I n s u f f i c i en t d alt a Indoor radon lehs than 2 pCi/l • I n door. radon be 1• e en 2 and 4 p Ci/ I Indoor radon gr~ater than 4 pCi/I ,,. %2:30 - 45• 22 20- 1::• 3000 ttt• 5220 1n• 3000 - Sc a I e 0 2 4 6 8 1 0 l L...:.::===::::Jl...... c:::====:::::Jl...... c:~~~ Mi I es \' 0 2 4 6 8 10 12 14 16 ' t " i I om e t;e r s ------· '. 222 - - Figure 33. Indoor Rn levels vs. soil Bi 214 activities for !the Portland area. ..' 111 rI• t t 1{!, ~ ,\ . .. I' . Salem soi chemistry Salem ~ no. .o o r· r ado n I e v e I s ';I. 'i'i'·. 123~1'00 4!5. 0000 :_J t::3• 0000 L e g e d ,5•0000 Salem so,1 chemistry ~ Bi-214 activity I••• than D.&I pCi/g (?5 Bq/kg) Bi-214 octiYity +41atcr than D.SI pCi/g (25 Bq/kg) -Salem indoo r a d o n l eve I s ~ Indoor radon l•tslthan 2 pCi/I Indoor radon b•l•~•n2 and 4 pCi/I - Indoor radon grea~crthan 4 pCi/I '='.,,00 1n• oo oo 1n• t5 oo ~' S c a I e ·t r r - - II i I es ·f - -· -· ~~} 3 7 ' Ki I tnlt I 1 r I ~' ------; Figure 34. Rn 222 . 214 t Indoor levels vs soil Bi activities for tlie' •f Salem area. ,i ,, i J '! l, .. 112 TABLE XX SOIL BI214 AND INDOOR RN222 ACTIVITIES FOR SELECTED PORTLAND AND SALEM AREA ZIP CODES Zip Code Ave. Soil Bi 214 Ave. Indoor Number of Number of Activity Rn 222 Activity. . Houses houses above a b b (pCi/g) (pCi/g) Tested 4 pCi/l b PORTLAND 97005 1. 03 1.3 28 0 97034 0.97 2.4 40 9 97035 1. 00 1.6 23 2 97201 0.95 1.4 36 2 97202 1. 02 2.6 10 2 97203 0.89 2.5 52 11 97206 1. 02 3.6 12 3 97210 0.96 1. 6 29 2 97211 0.85 3.4 41 18 97212 1. 03 4.4 84 34 97213 1. 03 5.2 71 37 97214 1. 01 2.2 17 3 97215 1. 05 2.0 27 0 97216 1. 03 1. 7 10 0 97217 0.87 4.3 17 8 97218 0.80 4.7 23 11 97219 0.92 1. 3 48 4 97220 0.92 6.6 32 15 97221 0.89 1. 7 36 3 97222 1. 00 2.2 16 3 97223 1. 02 1. 7 36 2 97224 0.98 1. 5 24 0 97225 0.98 2.2 38 7 97229 0.99 1.2 21 0 97232 1. 02 1. 7 12 2 97267 1. 01 1.4 15 0 113 TABLE XX SOIL BI214 AND INDOOR RN222 ACTIVITIES FOR SELECTED PORTLAND AND SALEM AREA ZIP CODES (continued) Zip Code Ave. Soil Bi 214 Ave. Indoor Number of Number of Activity Rn 222 Act1v1ty . . Houses houses above a b b (pCi/g) (pCi/g) Tested 4 pCi/l b SALEM 97301 0.88 2.4 12 2 97302 0.66 3.3 30 9 97303 0.85 1. 3 6 0 97304 0. 71 9.5 17 9 97306 0.73 4.1 13 2 214 Correlation coefficient (r = -0.32} between average soil Bi activity 222 and average indoor Rn activity in Portland is not significant at the 0.05 confidence level. 214 Correlation coefficient (r = -0.53} between average soil Bi activity 222 and average indoor Rn activity in Salem is not significant at the 0.05 confidence level. a Multiply pCi/g by 37 to convert to Bq/kg. Average radionuclide activities calculated with respect to the percentage of each geologic unit or formation within each Zip Code. b Data from the Oregon Department of Human Resources, Health Division (1994}. REGIONAL SOIL PERMEABILITY Soil permeabilities need to be taken into consideration in evaluating radon potential for the Pacific Northwest (Duval and Otton, 1989) because soil gas transport processes are significantly influenced by soil permeabilities (Duval and Otton, 1989) . Soil Conservation 114 Service Class names, saturated hydraulic conductivity, and intrinsic permeability used to establish soil and surface permeabilities for qualitative soil classification schemes are listed in Table XXI. Table XXI was used to establish TABLE XXI RELATIONSHIP BETWEEN SOIL CONSERVATION SERVICE PERMEABILITY CLASSES, SATURATED HYDRAULIC CONDUCTIVITY, AND INTRINSIC PERMEABILITY SCS Class Name Saturated Hydraulic Intrinsic Saturated Conductivity, kw Permeability ( cm2) b (in/hr) a 9 Very slow < 0.06 < 0.5 x 10- Slow 0.06 - 0.2 (0.5 - 1.6) x 10-9 Moderately slow 0.2 - 0.6 (1.6 - 4.9) x 10-9 Moderate 0.6 - 2.0 (0.5 - 1.6) x 10-8 Moderately rapid 2.0 - 6.0 (1.6 - 4.9) x 10-8 Rapid 6.0 - 20 (0.5 - 1.6) x 10-7 -7 Very Rapid > 20 > 1. 6 x 10 a These units are used by the Soil Conservation Service, 1 6 1 where 1 in. h- = 7.1 x 10- m s- • b The kinematic viscosity of water µw = O. 00137 Pa s at 15°C was used in the following conversion equation: k= kwµw Pwg (From Nazaroff and others, 1989). 115 soil intrinsic permeabilities for northwest Oregon from the Soil Conservation Service (SCS) class name or saturated hydraulic conductivity data of: Bowlsby and Swanson, 1964; Williams, 1972; Corliss, 1973; Otte and Others, 1974; Larsen, 1976; Howes, 1979; Green, 1981; Green, 1982, 1983; Knezevich, 1975, 1982; Gerig, 1985; Smythe, 1986; Langridge, 1987; Patching, 1987; and Smith and Shipman, 1988. Intrinsic permeabilities for northwest Oregon range from less than 0.5 x 10 -9 cm 2 to greater than 1. 6 x 10-6 cm2 (Bowlsby and Swanson, 1964; Williams, 1972; Corliss, 1973; Otte and others, 1974; Larsen, 1976; Howes, 1979; Green, 1981; Green, 1982, 1983; Knezevich, 1975, 1982; Gerig, 1985; Smythe, 1986; Langridge, 1987; Patching, 1987; and Smith and Shipman, 1988). Soil and surface deposits with intrinsic permeabilities greater than 1.6 x 10-7 cm2 are not geographically extensive in northwest Oregon. PORTLAND AND SALEM AREA SOIL PERMEABILITIES Intrinsic permeabilities for the Portland area range -7 2 -6 2 from less than O. 5 x 10 cm to greater than 1. 6 x 10 cm 116 (Green, 1982, 1983; and Gerig, 1985). Average intrinsic permeabilities for selected Portland area Zip Codes are listed in Table XXII. Areas identified by Toombs (1985) TABLE XXII 222 SOIL PROPERTIES AND INDOOR RN ACTIVITIES FOR SELECTED PORTLAND AND SALEM AREA ZIP CODES Zip Code Average Soil Average Soil Average Indoor Intrinsic Moist Bulk Rn 222 Rea d.ings Permeability Density (pCi/l) c (cm2) a,b (g/cm2) a,b PORTLAND 97005 4.2E-09 1.41 1. 3 97034 l.OE-08 1.42 2.4 97035 5.7E-08 1.41 1. 6 97201 1. OE-08 1. 35 1.4 97202 3.lE-08 1. 35 2.6 97203 5.9E-08 1. 37 2.5 97206 8.5E-08 1. 32 3.6 97210 l.7E-08 1. 30 1.6 97211 7.6E-08 1. 33 3.4 97212 4.5E-08 1. 34 4.4 97213 9.2E-08 1. 31 5.2 97214 3.2E-08 1. 33 2.2 97215 4.5E-08 1. 34 2.0 97216 4.8E-08 1. 30 1. 7 97217 6.lE-08 1. 35 4.3 97218 9.2E-08 1.40 4.7 97219 3.2E-09 1.44 1. 3 97220 8.9E-08 1. 35 6.6 97221 2.6E-09 1.44 1. 7 97222 2.8E-08 1. 34 2.2 97223 3.9E-09 1.41 1. 7 97224 2.4E-08 1. 38 1. 5 97225 1. SE-09 1.41 2.2 97229 2.SE-09 1. 39 1.2 97232 3.2E-08 1. 32 1. 7 97267 2.0E-08 1. 38 1.4 117 TABLE XXII SOIL PROPERTIES AND INDOOR RN 222 ACTIVITIES FOR SELECTED PORTLAND AND SALEM AREA ZIP CODES (continued) Zip Code Average Soil Average Soil Average Indoor Intrinsic Moist Bulk Rn 222 Read. ings Permeability Density (pCi/l) c 2 a,b 2 a,b (cm ) (g/cm ) SALEM 97301 2.2E-08 1.32 2.4 97302 2.8E-08 1.34 3.3 97303 l.6E-08 1.35 1. 3 97304 4.8E-09 1. 38 9.5 97306 1. 6E-08 1. 33 4.1 Correlation coefficient (r = 0.81) between average average intrinsic soil permeability and average indoor Rn222 activity for Portland is significant at the 0.05 confidence level. Correlation coefficient (r = 0.74) between average average intrinsic soil permeability and average indoor Rn222 activity for Salem is not significant at the 0.05 confidence level. a Average intrinsic permeability and moist bulk density calculated with respect to the percentage of saturated hydraulic conductivities for each soil series within each Zip Code. Portland Zip Codes calculated using data from Green (1982, 1983; Gerig (1985). b Average intrinsic permeability and moist bulk density calculated with respect to the percentage of saturated hydraulic conductivities for each soil series within each Zip Code. Salem Zip Codes calculated using data from Williams (1972); Knezevich (1982). c Data from the Oregon Department of Human Resources, Health Division (1994). and the Oregon Department of Human Resources, Health Division (1994), occur in areas with rapid to very rapidly -7 -7 2 drained soils ( O . 5 x 1 O - 1 . 6 x 1 O cm ) (Figures 35 and 3 6) . 118 ,, ·, P o r t I a n d s o permeab t y P o r t I a n d rtd o o r r a d o n I e v e I s ( t22• 5230 122• 30 00 122• 52 30 \ L e g e n d 45•3730 1n•3000 ~~~~~~~~~~-r-~~~-+- ~.1. ~ ~-~~ e• 3130 Portland sojil permeability - Intrinsic soil pernkability less than 1.6 x 10- 8 cm2 - Intrinsic soil pe ability between 1. 6 x 10- 8 and 4. 9 x 10- 8 cm2 - Intrinsic soil pe eability between 0.5 x 10- 7 and 1.6 x 10- 7 cm2 - Intrinsic soil permpability greater than 1. 6 x 10- 7 cm2 Po r t I and iln door radon I e v e I s D Insufficient data Indoor radon lesslthan 2.0 pCi/l .. 122• 52 30 •s•n30 122• 3000 Indoor radon between 2.0 and 4.0 pCi/l 122• 52 30 122• 30 00 - S c a I e 0 2 4 6 8 1 0 - Indoor radon greaqer than 4.0 pCi/l I.Ii I es -----0 2 4 6 8 10 12 14 16 t ~ -· - - - KilometC;rs -··- l 222 - - Figure 35. Indoor Rn levels vs. soil Bi 214 activities for the Portland area. i' ' 't 119 "' ,i ·''"1' i, ,. ,,~ ,, ·.·~ .. i ~ Salem so permeab t y Salem n·~1~·o r r ado n I e v e I s . ~ 1n• 1500 45• 00 00 12'3·~~ 123• 1500 123• 0000 oo=o nld I ..s• Lege "'~"'~"'~"'""''°""'""'""'""'""'"'"'"""''""'"'"""'<"<"'<"'<""<..- Sa I em so i I Ip er me c b i I i t y ~ Intrinsic soil pqrmeability less than 4.9 x io·• cm2 Intrinsic soil p~rmeabilitygreater than 4. 9 x io·• cm2 •Salem n door/ radon I e v e I s ~ Indoor radon less than 2.0 pCi/l Indoor radon between 2.0 and 4.0 pCi/l .... S2l0 1:3'•1soo •- Indoor radon gre,ter than 4. o pCi/l 1::t• 00 00 123• IS 00 123• 00 00 ~ Sc a I e . ~·. . i ,J II i I es ~~-- ~ Kilomet1r1 I f 222 ~ Figure 36. 214 i Indoor Rn levels vs. soil Bi activities for the Salem area. r" I, .! 120 Field observations in Portland suggest that elevated indoor radon (greater than 4.0 pCi/l) is closely associated with the coarse-grained facies of Missoula Flood sediments (Figure 5) . Moderate to low indoor radon levels (2.0 to 4.0 pCi/l and 0 to 2.0 pCi/l) are closely associated with annual flood sediments of the Columbia, Clackamas, Tualatin and Willamette Rivers, fine-grained facies of Missoula Flood sediments, Sandy River Mudstone and equivalent, Cascade Range and Columbia River basin derived Troutdale Formation, Columbia River basalts, Boring Lava and loess. Saturated hydraulic conductivities in the latter deposits are typically lower (Green, 1982, 1983; and Gerig, 1985). Intrinsic permeabilities characteristic of the Salem area range from O. 5 x 10-9 cm2 to 1. 62 x 10-9 cm2 (Williams, 1972; Knezevich, 1982). Average intrinsic permeabilities for selected Salem area Zip Codes are listed in Table XXII. Elevated indoor radon levels identified by Toombs (1985) and the Oregon Department of Human Resources, Health Division (1994), occur in areas with mapped landslides and colluvium (Bela, 1981) (Figure 6) . Field 121 observations in the areas mapped as landslide and colluvium confirm variability and non-homogeneity of near surface geology and soil horizons. Disturbed soil or unstable landforms often result in higher soil permeabilities until soil healing through pedogenesis occurs. On the Eola Hills, where elevated indoor radon has been reported (Toombs, 1985; the Oregon Department of Human Resources, Health Division, 1994), soil horizon boundaries vary from sharp to gradational. Cs137 activities were used to help verify the possibility of recent soil disturbances caused by landslides. Samples 82-B-la and 83-B-la, measured 5.3 +/-0.59 Bq/kg and 4.3 +/-0.19 respectively (sites 82 and 83) on the Eola Hills and indicate fairly stable surface conditions for at least the past 30 years for those locations (Burns, personal communication, 1991) . Both sites had gradational soil horizon boundaries. 122 DISCUSSION EVALUATING INDOOR RADON POTENTIAL Evaluating the indoor radon potential of northwest Oregon involves establishing a relationship between Rn222 source (soil gas concentrations) and the effects of soil permeability on soil gas transport processes to indoor ra d on. Estimating. . Rn 222 source can b e expresse d in . t h e following equation of Duval and Otton (1989) : Soi'l gas Rn 222 2650 n*d*e/ [ (1-s) (2. 65-d)] ( 5) 214 where n Bi• concentration,• d = moist. b u lk d ensity . o f soil, e = radon emanation coefficient, s = soil saturation (moisture), and 2650 (a constant) . Equation 5 represents the source component for indoor radon used in this study. The source component was then compared to actual indoor radon data to see what effect source potential had on indoor radon. To evaluate the effects of soil gas transport on indoor radon, a soil gas transport component equation was 123 derived. Observed Rn222 (measured indoor radon, Toombs, 1985; and the Oregon Department of Human Resources, Health Division, 1994) minus the Rn222 source component is considered to represent soil gas transport processes. The soil gas transport component is assumed to be related to soil permeability. This is represented by the following equation (Equation 6) . Soil gas transport ( eipxl07 ) ( 6) 2 where ip is intrinsic permeability (cm ) • The combined Rn 222 source and soi . 1 gas transport equation. is . s h own as a Rn 222 index. (Rn 222 I) below: . 7 Rn222I 2650/13 2 5 * n * d * e * / [ (1- s) ( 2 . 6 5 - d) ] * (e ipxio ) ( 7) Soil radionuclide and soil properties data of Portland were chosen to evaluate the source potential component and to derive the soil gas transport component (Equation 6) because of the good control of lithologic boundaries and soil characteristics. All averaged soil radionuclide and 124 soi. 1 properties . d ata an d in ' d oar Rn 222 rea d'ings were calculated at the resolution of Zip Code boundaries (Tables XX and XXII) . In Portland, there is a significant correlation (r 0.66) at the 0.05 confidence level between expected indoor Rn222 (Equation 7) and the actual average indoor. Rn 222 measurements. When Rn 222 source and soil gas transport components of Equation 7 are evaluated 222 separately with respect to measured indoor Rn , there are significant correlations between soil gas transport 222 component and measured indoor Rn (r = 0.75) and the between the source component and measured indoor Rn222 (r = -0.60) at the 0.05 confidence level. I believe that the correlation between source component and measured in. d oar Rn 222 is. t h e resu 1 t o f comparing. source component values derived from estimated variablies such as soil Bi214 activity, soil moisture, moist bulk density and Rn222 emanation, and comparing these derived numbers to values (indoor Rn222 levels) not related to chemistry. Regardless of the correlation between source component and measured 222 214 in' d oar Rn read' ings, t h e e ff ects o f B'i activity' ' on indoor Rn222 would be very small compared to soil gas 125 transport processes due to the narrow range of Bi214 activity found in the Portland area. Soil gas transport has a greater influence on indoor Rn222 because of a non- linear relationship between soil permeability and indoor 222 Rn . Soil permeability is clearly the controlling factor responsible for indoor radon in the Portland area. Figure 33 clearly illustrates the spatial distribution of Rn222 214 source (measured Bi ) and soil permeability for the Portland area. The narrow range of Bi214 activity shown in Figure 33 is expected since a significant component of sediment is derived from one source provenance (Columbia River drainage basin system). Soil permeability, shown in Figure 35, clearly identifies the outline of Alameda Ridge in north and northeast Portland, an area with known elevated indoor radon. If indoor radon in the Portland area is significantly influenced by soil permeability, other areas of interest include Lake Oswego and Durham. The most notable effects of soil gas transport are illustrated with basement and living area data from Portland. Table XXIII separates indoor radon data into two groups: 1) basements and 2) upstairs living areas 126 TABLE XXIII BASEMENT AND UPSTAIRS LIVING AREA DATA 214 Zip Code Intrinsic Soil Bi Ave. Basement Ave. Living 222 Permeability Activity Area Rn Area Rn222 (cm2) a,b (pCi/g) d Activity (pCi/l) c Activity (pCi/l) c PORTLAND 97005 4.2E-09 1.03 1. 5 1. 2 97034 1.0E-08 0.97 3.0 1.2 97035 5.7E-08 1. 00 2.4 1.1 97201 l.OE-08 0.95 1. 5 0.9 97202 3.lE-08 1. 02 3.1 nd 97203 5.9E-08 0.89 2.8 1. 7 97206 8.5E-08 1. 02 4.6 2.9 97210 1.7E-08 0.96 1. 6 0.7 97211 7.6E-08 0.85 5.2 3.3 97212 4.5E-08 1. 03 4.6 2.6 97213 9.2E-08 1.03 5.7 1.4 97214 3.2E-08 1. 01 1. 6 0.9 97215 4.5E-08 1. 05 2.0 0.8 97216 4.8E-08 1. 03 1. 9 1. 7 97217 6.lE-08 0.87 4.8 2.8 97218 9.2E-08 0.80 5.5 3.0 97219 3.2E-09 0.92 1. 3 0.8 97220 8.9E-08 0.92 7.9 3.2 97221 2.6E-09 0.89 1.7 1. 0 97222 2.8E-08 1. 00 1. 8 1.2 97223 3.9E-09 1. 02 2.6 1.1 97224 2.4E-08 0.98 1. 8 1.2 97225 l.8E-09 0.98 2.6 1. 4 97229 2.8E-09 0.99 1. 3 1. 2 97232 3.2E-08 1. 02 2.0 0.7 97267 2.0E-08 1. 01 1. 4 1.1 127 TABLE XXIII BASEMENT AND UPSTAIRS LIVING AREA DATA (continued) Zip Code Intrinsic Soil Bi 214 Ave. Basement Ave. Living Permeability Activity Area Rn222 Area Rn222 2 (cm ) a,b (pCi/g) d Activity (pCi/l) c Activity (pCi/l) c SALEM 97301 2.2E-08 0.88 2.9 2.3 97302 2.8E-08 0.66 3.4 3.1 97303 1.6E-08 0.85 0.9 1. 6 97304 4.8E-09 0. 71 13 .6 6.0 97306 1.6E-08 0.73 6.2 1. 7 a Soil data from Green, 1982, 1983; Gerig, 1985. b Soil data from Williams, 1972; Knezevich, 1982. c Data from the Oregon Department of Human Resources, Health Division, 1994. d See Tables XX and XXII for explanation of data. i.e. kitchen, bedroom, family, and dining rooms. Plotting intrinsic permeability of soil to basement (curve A) and upstairs living area (curve B) indoor radon data (Figure 37) reveals the following: 1) upstairs living areas and basements have linear and non-linear Rn222 accumulation segments, 2) the linear portion of indoor radon accumulation in upstairs living areas is over a wider range of intrinsic permeabilities than in basement areas, and 3) the boundary between linear and non-linear accumulation of indoor Rn222 in basements occurs at 0 00 0 r-- 0 \{) Non-linear o ..-i ...... -n 0 0 u LO 0 ~ 0 y 1. SeE+o1x N 0 N N i§ -qt H 6 0 0 0 6 0 0 6 6 'O M 06 ~ 0 Non-linear H Linear 0 0 0 0 N --~r--~------B~undary Y = o. 91e•••7X R2 = 0. 50 6 0 -- 6 rl 6 6 6 6 0 0 0.1 1.1 2.1 3.1 4.1 5.1 6.1 7.1 8.1 9.1 10·1 2 8 Intrinsic permeability (cm ) x 10- o Basements 6 Living areas - -Expon. (Living areas) -Expon. (Basements) j-j Figure 37. Soil permeability vs. basement and upstairs living areas data I\.) in Portland. CX> 129 8 2 approximately 5.0 x 10- cm • The last observation is particularly significant because it agrees fairly well with the calculated threshold values derived from equations 1 and 2 of Nazaroff and others (1989). Thus, soil gas transport potential relative to molecular diffusion and convective transport can be evaluated in terms of reservoir potential (the amount of radon available for transport) and the sustainability (the amount of time required to deplete the reservoir) . Non linear basement and upstairs living area radon data clearly support the conclusion of Duval and Otton (1989) that soil and rock permeabilities need to be included in assessing the indoor radon potential for the Pacific Northwest region. In Salem, the relationship between Rn222 source and soil permeability with indoor Rn222 is not obvious. Correlations between Rn222 source and indoor Rn222 (r = -0.53) and between soil permeability and indoor Rn222 (r = 0.74) are not significant at the 0.05 confidence level. This is largely due to the small population of indoor Rn222 measurements available and larger Zip Code 130 areas containing a variety of lithologies and soil properties. One thing is clear though, elevated indoor Rn 222 in. Sa 1 em, is . not contra 11 e d b y Rn 222 source. In fact, Bi214 soil activities in Salem are on average lower than those found in Portland. In Salem, elevated indoor Rn222 occurs in areas with mapped landslides (Figure 6). Soil disturbances are known to affect soil structure which can lead to increased soil permeabilities in many cases (Burns, personal communication, 1991) . The association between landslides and elevated indoor radon may offer a partial explanation as to why the soil permeability data of Williams (1972) and Knezevich (1982) fail to identify areas with elevated indoor radon. If landslide activity has resulted in increasing soil permeability, it is possible that conditions are favorable for convective soil gas transport 222 and elevated indoor Rn • Weak soil horizonization (A/Bw) with gradational horizon boundaries at sites S2 and S3, suggest either youthful soil horizons on a relatively stable surface (post disturbance) or continued soil disturbance at rates less than soil horizonation. The 131 Cs137 activity measurements of soils at sites S2 and S3 (Figure 13) indicate no reason to suspect surface soil disturbances within past 30 years (lower Cs137 activities) . However, soil disturbances at depth, not detected by Cs137 or from soil pit exposures, could still exist (Figure 38). Enhanced soil permeabilities at depths not represented by Williams (1972) and Knezevich (1982) would be consistent with the soil gas transport results for Portland. One of the difficulties associated with evaluating the indoor radon potential for Salem is that the indoor data set is small and the resolution is not very good (large Zip Codes areas) . It is almost impossible to predict with any degree of confidence where elevated indoor radon will occur in Salem. In addition, the geology is not nearly as homogeneous or widespread as is the case in Portland. The only apparent relationship between elevated indoor Rn222 and the location of its occurrence in Salem is that elevated indoor Rn222 occurs in areas with disturbed soils. Field inspection of some of the landslides in 132 The Alameda Ridge Missoula Flood sediment (coarse-grained) (soil drainage rapid to very rapid) Missoula Flood sediment (fine grained) . Soil drainage slow to moderate) SW liill!lllba.i--NE In Portland, the coarse-grained facies of Missoula Flood sediments (coarse sand, gravel and cobbles is often overlain by a fine-grained facies of silts and sand. In areas with just a thin capping of fine silt and sand, foundations can easily breach this cap. Houses on top of the ridge have a thin capping layer, often less th~n 100 cm in depth. Terraces stepping away from the Alameda Ridge have a thicker capping layer of fine silt and sand, reducing odds of having the foundation penetrate into the coarse-grained facies. once this cap is breached, the house is able to tap a much larger resevoir of soil gas, including radon through convective soil gas transport. The Eola Hills Disturbed upper surface soil horizons are healed (soil drainage varied from slow to moderately drained) . Disturbed subsurface soil horizons are not healed (soil drainage varied from slow to very rapid drainage) . Base of a landslide. s On the Eola Hills, soils have been locally disturbed by landslides. In areas where such disturbances have occurred, subsurface soil permeabilities may be high enough for convective soil gas transport. Upper surface soil horizons show signs of healing through the translocation of fines. Subsurface soil horizons show little signs of healing. Higher soil permeabilities (favorable for convective transport) is proposed as one explanation for elevated indoor radon in the area. Houses whose foundations breach the upper soil horizons similar to those on the Alameda Ridge of Portland could provide ideal conditions for convective soil gas transport and elevated indoor radon. Figure 38 Soil disturbance in Salem vs. Portland area 133 Salem indicates that increased soil permeabilities is likely. WEATHERING AND SOIL DEVELOPMENT Of particular interest in northwest Oregon are soils developed on Columbia River basalt. Weathering characteristics of Columbia River basalt in western Oregon 4 0 23 2 o ff er possi. bl e insig. . h t f or K an d Th activities• ' • observed in the area. In the Portland area, the thickest sequences of weathered basalts occur on flows that are largely vesicular or glassy (Beeson, personal communication, 1994). Differential rates of K40 removal by leaching in vesicular or glassy basalt flows compared to flows not having such textures, could produce some of the variations in soil K40 activity found in Columbia River basalt. The variation of K40 activities observed between Parrett Mountain, Eola Hills and Salem Hills could be from soil weathering fronts related to flow characteristics. Extreme weathering of basalts in some cases has shown significant leaching of K (Fassio, 1990) . Columbia River 134 basalt near Banks, Oregon can certainly be included in this category of weathering. Thorium may also be affected by weathering. However, in contrast to K which can be quite mobile, Th is relatively immobile in near surface environments (Muhs and others, 1990). Studies show that Th adsorption to clay, iron oxides, and oxyhydroxides is highest between soil pH of 2 and 5.4 (Bondietti, 1974; Langmuir and Herman, 1980). Soil pH values for all Ultisols sampled (Gerig, 1985; Otte and others, 1974; Williams, 1972; Knezevich, 1975, 1982) are well within the range for which Th adsorption is highest (Bondietti, 1974). High clay content in the soil matrices (Gerig, 1985; Otte and others, 1974; Williams, 1972; Knezevich, 1975, 1982), and Fe-oxides and hydroxides (Jackson, 1974 and Hoffman, 1981) support low Th mobility for these soils under present conditions. Bauxites analyzed by Fassio (1990) show that in some of these deposits, K has been depleted to levels 1/10 of unweathered basalt while Th concentrations are enhanced four to six times (Fassio, 1990) . Banfield and Eggleton (1989) and Fassio (1990) suggest mobilization of Th during 135 the earlier stages of basalt weathering, particularly the glassy phases. Variations of K and Th activity in Grande Ronde flows of Columbia River basalt between Parrett Mountain, the Eola Hills and the Salem Hills, and those of Fassio (1990) in Columbia County, could be the result of variations in basalt chemistry not detected by the analytical technique used in this study, or basalt texture. The amount of weathering and the erosion of Columbia River basalt highlands can also affect K40 and Th232 distributions. If Th232 and K40 mobilities observed in Columbia River basalt are related to soil pedogenesis and 23 2 4 0 soi. 1 weat h ering . f ron t s, s h i' f ts in ' Th : K activity• • ratios• similar to those observed for the lower to middle terraces of the Clackamas River can be expected. Excluding flow contacts and highly fractured zones favorable for water cond uits,. weat h ering . and T h2 3 2 :K4 0 activity• • ratios• s h ou 1 d decrease with depth. Areas where uplift and erosion have occurred, exposing progressively less weathered soil and rock, would also show a decrease in Th232 :K40 ratios. 136 Weathering and soil forming processes have significant influences on radionuclide distributions. In t h is. stu d y, soi . 1 Th23 2 : K4 o activity . . ratios . up to approximately· 0.1 + I - 0.02, appear to reflect K40 and Th232 activities close to that of the parent material regardless of erosion and deposition history, i.e. no effect on radionuclide activity. Significant correlations between Ac228 . 214 40 232 232 40 I Bi and K to Th for Th :K ranges of 0.03 to 0.08, 0.08 to 0.12, and 0.12 to 0.34 are listed in Table XXIV. Bot h Ac 228 and B i. 214 s h ow t h e h.ig h est corre 1 ation . 232 232 40 coefficient to Th in soils with Th : K ratios less than 0.08 and greater than 0.12. The opposite is true for K40 . In t h e case o f Ac 228 and B.i 214 , t h.is l ower corre l ation . for soils between 0.08 and 0.12 is interpreted to TABLE XXIV 228 214 CORRELATIONS BETWEEN Ac , Bi , 40 232 40 AND K WITH TH : K RATIOS Radionuclide Th232: K4o Correlation Ratio Range Coefficient a Ac22a 0.03 - 0.08 0.98 0.08 - 0.12 0.93 0.12 - 0.34 0.95 Bi 214 0.03 - 0.08 0.94 0.08 - 0.12 0.79 0.12 - 0.34 0.88 137 TABLE XXIV 228 214 CORRELATIONS BETWEEN Ac , Bi , 40 232 40 AND K WITH TH : K RATIOS (continued Radionuclide Th232: K4o Correlation Ratio Range Coefficient a K4o 0.03 - 0.08 0.88 0.08 - 0.12 0.90 0.12 - 0.34 0.67 Entisols < 0.08 Inceptisols, Mollisols, Alfisols, Vertisols 0.08 - 0.12 Ultisols > 0.12 a Significant at the 0.05 confidence level. 232 represent: 1) slightly higher mobilities than Th , and 2) higher cation exchange capacities as a result of 40 organic matter present. In the case of K , the highest correlation with Th232 occurs between 0.08 and 0.12. Weathering processes, including changes in pH, Eh, and cation exchange capacity can greatly affect the mobility and ionic substitution potential of silica, aluminum and cations (Birkeland, 1984). It is my opinion that soils in t h e 0.08 to 0.1 2 T h 23 2 : K4 o activity . . ratio· range h ave h a d sufficient time to make adjustments to new equilibriums and that stable secondary minerals are in part responsible for locking K40 in their structures. Root uptake and 138 organic decomposition is also capable of recycling K in near surface horizons. In both cases, the loss of soil K is reduced. In the case of Entisols, the lower corre 1 ation. b etween K4 0 and Th2 3 2 may in• d icate. an initia. . . 1 release of K from the breakdown of unstable primary 40 minerals. Similarly, the lower correlation between K and Th232 in Ultisols may indicate advanced weathering and leaching of cations, especially K, from more stable secondary minerals over a significant period of time. A1 t h ough t h e corre 1 ation· b etween B i. 214 an d T h232 activity. . is . high for all stages of soil weathering and development 232 observed in this study, Th activities do not always 214 accurately reflect Bi activities. Figure 39 illustrates 232 how Bi 214 activities change relative to Th activities for t h e range o f Th2 3 2 : K4 o activity . . ratios· o b serve d in· t h is· study. As soil weathering stages advance, as shown by the progressive· increase· in. t h e Th232 : K4o activity. . ratio, . T h232 activities become less useful in estimating soil Bi214 2 3 2 4 0 activities.· . . Th e Th : K activi• • t y ra t io . b oun d ary, f or 232 which Th activity appears to be useful as an indicator 214 of Bi activity and subsequently radon source potential, 50 - x 45 + 40 35 01 30 ~ .....__ 0'1 iri 25 N M C'J ..c::: 20 ~ ++ 15 ~ 10 /J+?-t+ + 5 t/ 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Bi 214 (Bq/kg} + 0 - 0. 08 x 0.08 - 0.12 x 0.12 - 0.33 - - --Linear (0 - 0.08) -..,--Linear (0.08 - 0.12) --Linear (0.12 - 0.33) t-1 F.igure 3 9 . B.i 214 vs. Th232 re l ative . to Th232 : K4o ra t. 10s. w \.0 140 is. approximate. 1 y 0.1 + I -0 . 0 2 . Th2 3 2 :K 40 activity. . ratios . above 0.1 indicate a degree of weathering capable of producing significant changes in the distribution of other 214 naturally occurring radionuclides, including Bi . It is important. to note t h at an increase . in. t h e T h232 :K40 activity ratio does not necessarily imply significant 214 changes in soil Bi concentrations from initial source rock concentrations. However, soils with ratios greater than 0.1 were the only ones to exhibit such changes. SPATIAL DISTRIBUTION OF NATURAL OCCURRING RADIONUCLIDES Geochemical results of this study support results of previous studies of the geochemistry of Tertiary marine sediments and Tertiary/Quaternary volcanics in northwest Oregon (Kadri and others, 1983; Lira, 1990; Lite, 1992; and Caldwell 1993). Kadri and others (1983), Lira (1990), Lite (1992), and Caldwell (1993) identified geochemistries from two source provenances: 1) distal plutonic and metamorphic terrane and 2) proximal volcanics. 141 RADON HAZARD POTENTIAL OF NORTHWEST OREGON In assessing the indoor radon potential for northwest Oregon, the regional geology was evaluated for dominant trends in lithologic composition and Bi214 activities. The indoor radon potential zones defined in this study consider soil gas transport to be linear. DEFINING RADON POTENTIAL ZONES Radon potential zones of this study are based on the 214 distribution of Bi activity in northwest Oregon soils. The radon potential zones were established along natural 1 it. h o l ogy b rea k s o f Ac 22a , B i. 214 , K4o , and Th232 activities.. . . Two radon potential zones are established, low (Ll and L2 subzones) and moderate (M) (Figure 40, Plate 1). Each zone represents an estimated range in soil Bi214 activity of 5.0 to 24.9 Bq/kg (Ll), 25 to 44.9 Bq/kg (L2), and 45 to 60 Bq/kg (M) respectively. 'I ·I~~,, 142 " 1. ~' .. 124 ° 121 ° 46° Radon Pottential Zones Ll 2 Projected indoor rtn u ac:~ic.y 10.s • l.O pCi/U 1 Soil 81Ju (Rau ) activity r,, .J: - 0.7 pC1/9• Ceol09ic tonn.U.or.s ::o.c c.hi ratinq include. but are not llmic.ed co: C:Ja•t Ranqe Province t Tcv. Tcq. Tpb. TtYll, Ty, T1n1, TpD Qtba. Tc. ft Tu·. Ti. ':'!a. Willamecce Valley Province - Oal, oyo, Qa, Qba, Og, OgC. VTg. T~eb We•C•nt C118C&de Province .) ~·· Tfc. Tc. ~••·Thi, } i:>, T'Yb, TU, Tu•, Trb, Tes•, Tmv H1gh Ca•cade• Province Oa, Oba, Q;, Q'Ta, Qgt, Ocb·!· Otd, Q'Tp, T:c. Titt :::ieactwce•-C~:.111•Province QDa, QTa, ~. QTba, OT'?! iev, Tc, Ts, T:a. Tew, Tcg, Tp. TVi High t..ava Plain. Province n Qt>. QTb. O!. C'Tll· 01WV Oc:hOeo·Blue Mountain• ProJ'1rtc:e •l"eo 'Ibo Tob, QTp, QTlft¥' u Projected indoor Rnua aC1:1.;ii:;• n.:J • 2.0 pC1/lJ 116 Soil 11'-H (Ra ) •ct!Vlty ( . 7 .. 1.2 pC!/9J Ceolo;ic: !ortMtiorw tor thi· :at.1n9 1.nclude. but ere not lirnit•d to: Co••C Ranqe Province Qal. Qd. o:. ou. or.. nu. -q. Ta. Teo. Tse. Te. Tmsa. Ts• W1Uamec:e Valley PrcYtnce CTs. Oc. Os. T!~. T!ee. T~11n westem Cascade Prov1nce 09•. OT•. Qt. T1v H19'h C.•c:ade• Province Tsv. Tm Deacnuc.ea•OIMC.ill• ProvinC9"' T•v, Ta. Tc:a. Tr. Trh : Hi9b. L•v• Plain• Provtnce QTst. Tee. Ts!j. Trh Oc:hOc:O·llu• f'IO\lnt•iNI Provlnte Ta!j M 211 Projected indoor Rn acc\vt.itv 12.0 .. 4,0 pCi/U 11 216 Sail a1 • (Aa J activity 11 : .. L' pCl/gl Ceol09ic !o:1Mtion• for th~•:.atinq include. but are not Umtted cc:i: Coaae Range Province ' Tlut, Tsd WUl•-tt:e valley Province - T•d w.scern Cascade Province None Hiqn Caacad•• Prcvtnce NOne De•chucca•Umaeilla Provt.nce None Hl9h Lava Plain• Province None Oc:hOC:O•Blue MOuntains Prov1n None 44° S c a I e ... .. II It .. 121 ° 124° " ...... "ti .. " ...... ,.,. it " '• ' Figure ao. Rn--2'"' potentia . 1 map o f northwest Oregon based on soil Bi 214 activity. See Plate 1 •, ..:f'!• 143 LITHOLOGY OF RADON POTENTIAL ZONES Throughout northwest Oregon, Ll subzones are essentially confined to undifferentiated basalts and andesites. Tertiary marine sediments derived from proximal volcanic sources can also be included in some of the Ll subzones. L2 subzones are dominantly comprised of glaciofluvial and glacio-eolian sediment and marine sediment derived from the Idaho Batholith area (Heller and others, 1985), and rhyolitic Cascadian volcanic ash. M zones are almost exclusively limited to marine sediments characteristic of the plutonic and metamorphic sources. Within each of the assigned zones are areas with the potential for significant radionuclide redistribution though weathering and soil forming processes. However, all the radionuclide activity data of this study indicate that even with such radionuclide redistributions, Rn222 source potential has not been significantly affected. PREDICTED INDOOR RADON FOR NORTHWEST OREGON If the association between lithology (surface Bi214 activities) and indoor radon of Duval and Otton (1989) is 144 applied to this study, average annual indoor radon levels in the ranges of 0.5 to 1.0 pCi/l, 1.0 to 2.0 pCi/l, and 2.0 to 4.0 pCi/l for Ll, L2 and M potential zones respectively should be expected throughout northwest Oregon for areas with subsurface intrinsic permeabilities on the order of 10 -8 cm 2 and less. Of the estimated 48,500 square kilometers which comprise northwest Oregon, 62% is rated as Ll; 35% is rated as L2; and 3.0% is rated as M. It appears that natural geologic sources within the study area are not capable of producing indoor radon levels above 4 pCi/l. Local geologic conditions (i.e. soil permeability) and/or building characteristics (i.e. building material, ventilation) are certainly capable of producing such levels even if radon source potentials are low. PREDICTED INDOOR RADON FOR PORTLAND AND SALEM In this study, the net effect of soil Bi214 activity and soil permeability on indoor radon is best illustrated in Portland (Figure 41, Plate 3)). A rating system (Table '!.. '' "{ ~l ~·~ 145 "'[,l .,(; . ~-""~ 122 ° 52' 30" :1 . ·~ 122 ° 30' 00" 45 ° 37' 30" ,'; I 45 o 37' 30" Radon ·Eotential Zones Low rotin9 - ~.p1ct1dindoor radon ~ less thon Z pcli/I. Modero!• ra!inl7 - ezpected in~oorradon bt tween Z on.d I pCi·/ I. Hi9h rotinq - prpected indoor radon • ir•oter thoo 41pCi/I. N Sc al I e ~ a 2 I J + .s T I.Ii I es ~ a 2 3 ~ 5 7 a 45 ° 22' 30" ~ "'"»M-"~4.Th".~~""'~"'~~~~~~~~~45 ° 22' 30" 1 ~- i Kilometers ') 122 ° 52' 30" •\ ~ ~ 11· 122 ° 30' 00" r Figure 41. Indoor Rn:::::: potential map of Portland bas~don the radon index system.· See Plate 3. !t.'! j~ !t ~' 146 XXV) taking into account soil radionuclide activity and soil permeability was developed with the following in mind: 1) the narrow range of soil radionuclide activity on indoor radon produces linear results, and 2) the effect of soil permeability on indoor radon produces non-linear results (based on the results of this study) . Multiplying the two rating columns together in Table XXV produces total radon index numbers one through four, six and TABLE XXV INDOOR RADON RATING SYSTEM Soil Radionuclide Rating Intrinsic Rating Activity (pCi/g) Permeability 2 (cm ) Less than 0.68 1 < 1.6 x 10-8 1 Greater than 0.68 2 1.6 - 4.9 x 10-8 2 7 0.5 - 1.6 x 10- 3 7 > 1.6 x 10- 4 eight. Areas where the radon index numbers are of two or less are assigned a low rating. Radon index numbers of three and four are assigned a moderate rating, while numbers six and eight are assigned a high rating. This 147 rating scheme is consistent with the regional radon potential map of this study. For example, an area with Bi214 activities greater than 0.68 pCi/g (25 Bq/kg) and moderately rapid rates of soil drainage (2 to 6 inches/hr.), would produce a radon index number of four (the maximum number possible for a moderate indoor radon potential rating and the highest radon potential zone assigned to the regional map) . Higher soil permeabilities like those found in the Alameda Ridge area of north and northeast Portland would move the site into a high indoor radon potential rating (elevated indoor radon) as shown in Figure 41. However, applying the same rating system to the Salem area is less successful because the resolution of the soil data is poor relative to areal extent of local soil disturbances. Figure 42 (Plate 4) illustrates the predicted distribution of indoor radon excluding this factor. If types of soil disturbance could be included as a modifier to soil permeability, predicting indoor radon in these kinds of areas where such processes occur might be possible. I, ' .1. 148 ! ..' , "( .~ ' ,~ i l~ ~ ~ i 'I" .I ' ~" 123 ° 15' 00" 123° 00' 00" ' 45° 00' 00" (.~ 45° 00' 00" h Radon Zones low rating - expected ~ less than % pCi/I. Moderate rating - expect~ind9,or radon between% and 4 pCi/I. ' ',. v.~ri~I ~lI!. - "~. 11.t .A'.;1 ~· N .-,'l r,,, 0 2 3 4 ~1 5 a 44° 52' 30" Kilometers 123 ° 15' 00" 123 ° 00' tb~52' 30" 1· Figure 42. Indoor Rn222 potential map of Salem based the radon index system. See Plate 4. r i l. ! i· 149 CONCLUSIONS Radionuclide data of northwest Oregon show that h ig. h est Ac 228 , Bi. 214 , K40 and T h232 activities. . . are not 232 40 necessarily found in the B horizon. Th : K radionuclide ratios provide valuable information on the weathering stage of soils, soil history and radionuclide 232 redistribution in near surf ace environments. Th : K40 activity ratios less than 0.08 typically reflect the primary mineral geochemistry of the parent material(s) . 214 226 Bi. an d su b sequent 1 y R a estimates. can b e ma d e wi . th Th232 data with a fair degree of confidence even though Th232 is not part o f t h e same d ecay series.. Th232 : K4o ratios. greater than 0.12 may not necessarily reflect the primary mineral geochemistry of the parent material and are potential indicators of the likelihood and degree of possible radionuclide redistributions. One site where significant radionuclide redistribution has occurred is near Banks, Oregon. Bauxites developed on Columbia River basalt in Columbia County (Fassio, 1990), having Th concentrations 4 to 6 times higher than normally 150 associated with Columbia River basalt, is strong candidate 214 for elevated soil Bi activities. Soils in northwest Oregon developed on or from sediment derived from the Columbia River drainage basin source provenance (Missoula Flood sediments, loess, fine- grained f acies of the Troutdale Formation) reflect K40 and 232 Th activities of plutonic and metamorphic terranes (Lite, 1992). Soils developed on or from sediments derived from Tertiary marine sediment reflect both distal plutonic/metamorphic terrane, and proximal volcanic arc and oceanic arc terrane. Soils developed on or from Tertiary marine sediments (Tyee and Cowlitz formations) largely derived from plutonic and metamorphic terranes, 40 232 have similar K and Th activities of sediment derived from the Columbia River basin. Soils developed on or from Tertiary marine sediments with mixed plutonic/metamorphic and volcanic arc and oceanic arc terrane (Keasey and 40 232 Pittsburg Bluff formations) show varied K and Th activities. Soils developed on or from sediments largely derived from volcanic arc and oceanic arc sediment reflect K4 0 an d T h2 32 activities . . . d erive . d f rom proxima. 1 vo 1 canics. . 151 Soils developed on or from Cascade volcanics show a fairly 40 232 large range in K and Th , as reflected by basaltic, andesitic and rhyolitic rock compositions. Bi214 radionuclide activities in the study area do not correlate well to areas with elevated indoor radon. Areas with elevated indoor radon do correlate well with soil gas transport. Variations in indoor radon are essentially controlled by soil permeability. In Portland, coarse grained cobbles, gravels and sands of the Multnomah soil series appear to be the most extensive geologic deposit responsible for elevated indoor radon. The lowest indoor radon values in the Portland area are associated with fine-grained sand, silt, and clay where saturated hydraulic conductivity is less than 2 inches/hr. In the Salem area, the highest indoor radon values are present in areas that have been subjected to landslide activity. Weathering and soil pedogenesis at the near surface could effectively reduce near surface soil gas transport to levels below that where convection is the dominant mechanism for soil gas transport. It is my opinion that higher permeabilities, outside the range 152 where molecular diffusion is the dominant soil gas 7 2 transport mechanism (approximately 5 x 10- cm- ) , probably exist at depth. Based on soil Bi214 activity levels in northwest Oregon, it appears that natural geologic radon sources under typical soil permeabilities are not capable of producing elevated indoor radon levels above 4.0 pCi/l. Bi214 activities in northwest Oregon soils indicated two categories of radon potential: low (Ll and L2 subzones) and moderate (M} . These radon potential zones represent an estimated range in soil Bi214 activities of 5.0 to 24.9 Bq/kg (Ll}, 25 to 44.9 Bq/kg (L2), and 45 to 60 Bq/kg (M) respectively. Of the estimated 48,500 square km which make up northwest Oregon, 62% is rated as Ll and is found on mainly basalts, andesites and Tertiary marine sediments from proximal volcanic sources; 35% is rated as L2 and is found on glaciofluvial and glacio-eolian sediment and marine sediments derived from plutonic and metamorphic sources and rhyolitic Cascadian volcanic ash; and 3.0% is rated as M and is exclusively limited to marine sediments derived from plutonic and metamorphic sources. 153 The indoor radon potential assessment of this study, based solely on the Bi214 activities of soils in the study area, supports Duval and Otton's (1989) assessment of low to moderate indoor radon potential for the Pacific Northwest. However, there are areas, including portions of Portland and probably Salem where high soil permeabilities produce elevated indoor radon. This study further confirms the importance of soil gas transport in evaluating indoor radon in the Pacific Northwest. 154 FUTURE WORK The relationship between naturally occurring ra d ionuc. 1 i. d es an d t h eir . ratios . ( particu . 1 ar 1 y T h2 3 2 :K4 0 activity ratios) to lithology and weathering processes (including soil development) as identified in this study should be applied to Instrumental Neutron Activation Analysis (INAA) data. Further work should be directed toward weathering processes relative to lithology and radionuclide migration in soils. One question which needs to be answered is: how much time or weathering is needed to produce higher radionuclide activities in B horizons. Further work should also focus on chronosequencing the Willamette Valley, and the Portland and Tualatin basin geomorphic surfaces. 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V., 1989, Factors influencing soil as a source of indoor radon: Framework for assessing radon source potential: United States Department of Energy, p. 111. Yeats, R. S., Graven, E. P., Werner, K. S., Goldfinger, C., and Popowski, T., 1991, Tectonics of the Willamette Valley Oregon: U.S. Geological Survey, Open File Report 91-441-P, 41 p. S3~dW\fS a.NV ssirs ~IOS dO NOiidI~0S3Q V XIQN3ddV 991 Description of Sites Site County Quadrangle a UTM East UTM North Elev. (m) Veg. Drain. b Geol. c Soil ct Cl MULTNOMAH PORTLAND 7.5 522049 5039042 191 df 2,3 Qs 18D 4 C2 WASHINGTON HILLSBORO 7.5 503643 5046637 55 df 3 Qs 45A 3 C3 WASHINGTON BUXTON 7.5 487002 5056635 122 df 3 Tc 36D 3 C4 WASHINGTON BUXTON 7.5 483559 5059728 146 df 3 Tmst 36C 3 cs COLUMBIA CLEAR CREEK 7.5 475233 5076304 441 df 3 Teo 620 10 C6 WASHINGTON TIMBER 7.5 478660 5065818 340 df 3 Tss 33E 3 C7 WASHINGTON CLEAR CREEK 7.5 473195 5069554 267 df 3 Teo 56D 3 CB CLATSOP ELSIE 7.5 453382 5073882 116 s 3 Ttv 22F 9 C9 CLATSOP SADDLE MTN 7.5 447913 5082998 122 df 3 Tss 58E 9 ClO CLATSOP SADDLE MTN 7.5 447059 5083464 407 h 3 Ti SBE 9 Cll CLATSOP TILLAMOOK HEAD 7.5 429230 5090474 15 df,s 3 Tms 35B 9 C12 TILLAMOOK COCHRAN 7.5 462768 5062718 733 df 3 Ttv nd Cl3 BENTON WREN 7.5 466104 4937226 146 df 3 Tsr JoD 1 Cl4 BENTON DIGGER MTN 7.5 449814 4906902 182 df 3 Tt AcE 1 C15 BENTON DIGGER MTN 7.5 449880 4906339 255 df 3 Tt BnE 1 Cl6 BENTON ALSEA 7.5 460054 4923704 380 df 3 Tsr BLE 1 Ml CLACKAMAS RHODODENDRON 7.5 578682 5022223 366 df,c 3 Tf c/Qal 44B 2 M2 CLACKAMAS RHODODENDRON 7.5 581417 5018888 474 df,m 3 Thi 63B 2 M3 CLACKAMAS (N. F. ) RHODODENDRON 7.5 585815 5019067 518 df ,c 3 Tf c/Qal 345 5 M4 CLACKAMAS ( N. F. ) GOVERMENT CAMP 7.5 595656 5017183 1106 df 3 Qbaa 333 5 MS CLACKAMAS (N. F. ) MOUNT HOOD SOUTH 7.5 601650 5017695 1459 h,tf 3 Qa 382 5 M6 CLACKAMAS(N. F. ) MOUNT HOOD SOUTH 7.5 603308 5015023 1252 df 3 Trb 333 5 M7 CLACKAMAS ( N. F. ) MT. WILSON 7.5 602981 5005326 1191 df 3 QTa 352 5 MS JEFERSON ROUND BUTTE DAM 7.5 637441 4933297 620 j,sb 3 Ts nd M9 JEFFERSON ROUND BUTTE DAM 7.5 639027 4933925 790 sb 3 Ts nd MlO JEFFERSON CULVER 7.5 647676 4940502 729 g 3 Ts nd Mll JEFFERSON EAGLE BUTTE 7.5 639253 4960466 486 pp,j,sb 3 Tsf j Ml2 JEFFERSON nd WARMSPRINGS 7.5 631098 4962527 790 .pp, j, sb 3 Tob nd Ml3 WASCO HEHE BUTTE 7.5 623961 4971108 802 sb,g 3 QTg nd Ml4 WASCO HEHE BUTTE 7.5 627175 ~980627 742 pp,j,g 2,3 Tea nd M15 WASCO SIMNASHO 7.5 630735 4982276 790 pp,j,sb,g 3 Tsf j nd M16 WASCO WAPINITIA 7.5 634767 4991684 681 j,sb,g 3 Tcg nd M17 WASCO FOREMANPOINT 7.5 620659 4995427 960 pp,df 3 QTba nd r-i M18 MARION DETROIT 15 564920 4952727 486 df ,vm 3 Tu nd O"I .....J ------,-~-~·----_,,------~------·-·------a Site County Quadrangle UTM East UTM North Elev. (m) Veg. Drain. b Geol. c Soil ct Ml9 LINN DETROIT 15 572999 4949046 608 df 3 Tu nd M20 LINN MT. JEFFERSON 15 583707 4944123 729 df ,h,c 3 QTba nd M21 LINN THREE FIN. JACK 15 580192 4925274 1143 df 3 QTba nd M22 LINN THREE FIN. JACK 15 583605 4920961 1119 df 3 QTp nd M23 LINN THREE FIN. JACK 15 590619 4918395 1489 s,df,lp 3 Qba nd M24 JEFFERSON BLACK BUTTE 7.5 572420 4916602 1079 pp 3 Qba/Qg nd Pl MULTNOMAH PORTLAND 7.5 528311 5044245 79 nd 3 Qgs 52A 4 P2 MULTNOMAH PORTLAND 7.5 554815 5018163 79 nd 3 Qgs 52A 4 P3 MULTNOMAH PORTLAND 7.5 527879 5045407 58 nd 3 Qgs SlA 4 P4 MULTNOMAH PORTLAND 7.5 528949 5042701 46 nd 3 Qs SlA 4 PS MULTNOMAH PORTLAND 7.5 526892 5043608 58 nd 3 Qs SlA 4 P6 MULTNOMAH LINNTON 7. 5 513128 5049466 280 df 3 Qs 7C 4 P7 MULTNOMAH PORTLAND 7.5 520862 5042653 261 df 3 Qs 7C 4 P8 CLACKAMAS ESTACADA 7.5 554815 5018163 267 g 3 QTba 2D 2 P9 CLACKAMAS ESTACADA 7.5 553925 5018732 261 df 2 I 3 QTba 28 2 PlO CLACKAMAS ESTACADA 7.5 551620 5019797 207 a,hw 3 QTba 17 2 Pll CLACKAMAS REDLAND 7.5 548523 5018316 76 df ,vm,og 3 QTba/Qal 68 2 Pl2 CLACKAMAS ESTACADA 7.5 549544 5019348 117 df ,og 3 QTba 77B 2 Pl3 CLACKAMAS DAMASCUS 7.5 541212 5027009 58 df 3 Ts 91B 2 Pl4 MULTNOMAH SAUVIE ISLAND 7.5 518251 5054374 6 cw,b 3 Qal 33 4 Pl5 MULTNOMAH CAMAS 7.5 541144 5039793 76 df 3 Qgs 52A 4 Pl6 MULTNOMAH PORTLAND 7.5 523521 5039058 198 m,df 2,3 Qs 7E 4 Pl7 CLACKAMAS OREGON CITY 7.5 533155 5020282 73 a,m 2 Ts 92F 4 Pl8 CLACKAMAS OREGON CITY 7.5 533053 5020069 116 a,m 3 QTba 45B 4 Sl POLK SALEM WEST 7.5 491579 4976118 228 0 3 Tsd 76E 7 S2 POLK SALEM WEST 7.5 491580 4976053 222 0 3 Tcg 76E 7 S3 POLK SALEM WEST 7.5 491691 4976049 231 0 3 Tcg 76E 7 S4 POLK SALEM WEST 7.5 491622 4976024 228 nd 3 Tcg 76E 7 SS POLK SALEM WEST 7.5 492013 4975264 73 m,df 3 Tcg 61E 7 S6 POLK SALEM WEST 7.5 491838 4977670 213 df ,m 3 Tcg 52D 7 S7 POLK SALEM WEST 7.5 496863 4976953 6 m,a,cw 3 Qal 79 11 SS MARION SALEM WEST 7.5 497483 4975055 46 o,g 3 Qs Sa 11 S9 MARION SALEM WEST 7.5 492343 4973847 43 cw,g 3 Qal Nu 11 SlO MARION SALEM WEST 7.5 498126 131 df 3 Tcg JoB 11~ 4969207 0\ ()) a b c Site County Quadrangle UTM East UTM North Elev. (m) Veg. Drain. Geol. Soil d Sll MARION SIDNEY 7. 5 499150 4963674 152 o,g 3 Tcg NeF 11 Sl2 MARION GERVAIS 7.5 505693 4994240 55 cw,po 2 Qs Co 11 Wl WASHINGTON BEAVERTON 7.5 519284 5025030 36 g 1 Qs/Qal 43 4 W2 WASHINGTON SHERWOOD 7.5 518563 5022416 100 df,s 3 Qs 21B 4 W3 MARION SHERWOOD 7.5 517701 5013384 55 df 3 Qs 91A 11 W4 MARION NEWBERG 7.5 507600 5011319 53 0 3 Qal Cm 11 W5 YAMHILL GRAND RONDE 7.5 457126 4993949 207 df 3 Ty PCE 8 W6 YAMHILL GRAND RONDE 7.5 451290 4994789 134 df 3 Teo PeB 8 W7 YAMHILL NEWBERG 7.5 509234 5016806 350 g 3 Tc JrC 8 W8 WASHINGTON SHERWOOD 7.5 512110 5019153 213 df 3 Tc 38D 4 W9 WASHINGTON SHERWOOD 7.5 515080 5016470 49 df 3 Qs 91B 4 a Key to Vegetation - a: alder, c: cedar, cw: cottonwood, df: Douglas fir, g: grass, h: huckleberry, j: Juniper, lp: Lodgepole Pine, m: maple, o: oak, og: Oregon grape, po: poison oak, pp: Ponderosa pine, sb: sagebush, tf: true fir, vm: Vine maple. t; Key to drainage - 1: poorly drained, 2: moderately drained, 3: well drained. Qa - Andesite, Qal - Alluvial deposits, Qba - Basaltic andesite and basalt, Qbaa - Basaltic andesite and andesite, Qgs - Glacial fluvial, lacustrine and pediment sedimentary deposits, Qs - Lacustrine and fluvial sedimentary rocks, Qta - Andesite, QTba - Basalt and basaltic andesite, Qtg - Terrace gravels, QTp - Pyroclastic rocks of basaltic and andesitic cinder cones, basaltic and andesitic ejecta, Tc - Columbia River Basalt Group and related rocks, Tea - elastic rocks and andesite flows, Tcg - Grande Ronde Basalt, Tfc - Flows and elastic rocks, undifferentiated, Thi - H~abyssal rocks, Ti - Mafic intrusions, Tms - Marine sedimentary rocks, Tmst - Marine sedimentary and tuffaceous rocks, Tob - Olivine basalt, Toe - Cowlitz Formation, Trb - Ridge-capping basalt and basaltic andesite, Tsr - Siletz River Volcanics, Tss - Tuffaceous siltstone and sandstone, Tsfj - John Day Formation, Tt - Tyee Formation, Ttv - Tillamook Volcanics, Tu - Undifferentiated tuffaceous sedimentary rocks, tuffs and basalt, Ty - Yamhill Formation (Walker, G. W. and MacLeod, N. S., 1991). d 1 - Corliss, J. F. (1973); 2 - Gerig, A.J. (1985); 3 - Green, G. L. {1982); 4 - Green, G. L. (1983); 5 - Howes, S. {1979); 6 - Knezevich, C. A. (1975); 7 - Knezevich, C. A. (1982); 8 - Otte, G. E., Setness, D. K., Anderson, W. A., Herbert. F. J. Jr., and Knezevich, C. (1974); 9 - Smith, P. R., and Shipman, J. (1988); 10 - Smythe, R. T. ( 19 8 6) ; 11 - Wi 11 i ams, L. H . ( 19 72) . ~ O'I l...O 170 Description of Soil Samples * b Sample Horizon Depth Color Texture a Structure C1-A-1a A 0-5 10YR 5/3 L 1m, sbk C1-B-1a Bt 5-27 10YR 6/4 L sbk C1-A-2a A 0-20 10YR 5/3 L sbk C1-B-2a Bt 20-45 10YR 6/4 L sbk C2-A-1a A 0-13 10YR 6/2 L m C2-B-1b Bw 13-50 10YR 6/3 L m C2-B-1a Bw 13-50 10YR 6/3 L m C2-A-1a A 0-13 lOYR 6/2 L m C2-B-2a Bw 13-50 lOYR 6/3 L m C3-A-la A 0-20 lOYR 4/3 c 2m, sbk C3-B-la Bs 20-250+ SYR 4/6 c 3m, sbk C3-A-2a A 0-20 lOYR 4/3 c 2m, sbk C3-B-2a Bs 20-250+ 5YR 4/6 c 3m, sbk C4-A-la A 0-20 7. 5YR 3/4 SiL g C4-B-la Bt 20-60 lOYR 6/6 Si CL 2m,sbk C4-A-2a A 0-20 7. 5YR 3/4 SiL g C4-B-2a Bt 20-60 lOYR 6/6 SiCL 2m, sbk CS-A-la A 0-5 10YR 4/3 SL g C5-B-la Bw 13-50 lOYR 6/4 SCL lm, sbk C5-A-2a A 0-5 lOYR 4/3 SL g C5-B-2a Bw 13-50 lOYR 6/4 SCL lm, sbk C6-A-la A 0-5 lOYR 5/3 SiL g C6-B-la Bt 10-45 lOYR 6/4 CL lm, sbk C6-A-2a A 0-5 lOYR 5/3 SiL g C6-B-2a Bt 10-45 10YR 6/4 CL 2m, sbk C7-A-la A 0-17 10YR 4/3 SL lm, sbk C7-B-la Bt 17-50 lOYR 5/3 SCL 2m, sbk C7-A-2a A 0-25 10YR 4/3 SL lm, sbk C7-B-2a Bt 25-50 lOYR 5/3 SCL 2m, sbk CS-A-la A 0-25 lOYR 3/3 gSL lm,sbk C8-B-la Bt 25-50 lOYR 4/3 gSL 2m, sbk CB-A-2a A 0-25 lOYR 3/3 gSL lm, sbk C8-B-2a Bt 25-50 10YR 4/3 gSL 2m, sbk C9-A-la A 0-50 lOYR 3/3 gSL lm, sbk C9-B-la Bw 50-80 lOYR 4/3 gSL 2m, sbk C9-A-2a A 0-50 lOYR 3/3 gSL lm, sbk C9-B-2a Bw 50-80 lOYR 4/3 gSL 2m, sbk C10-A-2a A 0-12 lOYR 2/2 SiL sbk C10-B-2a Bt 12-45 lOYR 4/4 CL sbk C11-A-la A 0-10 lOYR 2/2 LS g,m C11-B-la Bw 10-55 lOYR 4/4 SL lm, sbk C11-A-2a A 0-10 lOYR 2/2 LS g,m Cll-B-2a Bw 10-55 lOYR 4/4 SL 2m, sbk Cl2-A-la A 0-5 lOYR 2/2 SL lm, sbk C12-B-la Bw 5-35 lOYR 2/2 SL 2m, sbk 171 b Sample Horizon Depth Color Texture a Structure Cl3-A-la A 0-25 lOYR 4/3 SL g,m Cl3-B-la Bw 25-50 lOYR 4/3 CL 2m, sbk Cl4-A-la A 0-20 lOYR 6/6 SiL g,m Cl4-B-la Bw 20-60 lOYR 4/3 Si CL 2m, sbk Cl5-A-la A 0-30 lOYR 6/3 SL g,m Cl5-B-la Bw 30-80 lOYR 6/4 SL 2m,sbk Cl5-C-la c 80-450 lOYR 6/4 LS m Cl6-A-la A 0-25 7. 5YR 6/4 SiCL g,m Cl6-B-la Bt 25-100 7. 5YR 6/5 SiCL 2m, sbk Cl6-C-la Cox 100+ lOYR 7/4 N/A m Ml-A-la A 0-15 7. 5YR 6/2 SL g,sg Ml-B-la Bw 15-45 lOYR 5/4 LS g,sg Ml-A-2a A 0-20 7. 5YR 6/2 SL g,sg Ml-B-2a Bw 20-45 lOYR 5/4 LS g,sg M2-A-la A 0-8 2. 5YR 5/2 LS g,sg M2-B-la Bw 15-37 lOYR 4/3 SL g,sg M2-A-la A 0-8 2. 5YR 5/2 LS g,sg M2-B-2a Bw 15-37 lOYR 4/3 SL g,sg M3-A-la A 0-5 5YR 3/1 LS g,sg M3-B-la Bw 5-25 7. 5YR 6/2 SL m M3-B-lb Bw 5-25 7. 5YR 6/2 SL m M3-A-2a A 0-5 5YR 3/1 LS g,sg M3-B-2a Bw 5-37 7. 5YR 6/2 SL m M4-A-la A 0-8 7. 5YR 3/4 LS g,sg M4-B-la Bt 8-60 lOYR 6/4 LS m M4-A-2a A 0-8 7. SYR 3/4 LS g,sg M4-B-2a Bt 8-60 lOYR 6/4 LS m MS-A-la A 0-15 lOYR 5/2 LS g,sg M5-B-la Bw 15-45 lOYR 6/3 SL g,sg M5-A-2a A 0-15 lOYR 5/2 LS g,sg M5-B-2a Bw 15-45 lOYR 6/3 SL g,sg M6-A-la A 0-20 lOYR 4/1 LS g,sg M6-B-la Bw 20-50 lOYR 6/4 LS g,sg M6-A-2a A 0-20 lOYR 4/1 LS g,sg M6-B-2a Bw 20-50 lOYR 6/4 LS g,sg M7-A-la A 0-5 lOYR 3/1 LS g,sg M7-B-la Bt 5-30 lOYR 6/4 SL g,sg M7-A-la A 0-5 lOYR 3/1 LS g,sg M7-B-2a Bt 5-30 lOYR 6/4 SL g,sg MS-A-la A 0-15 lOYR 4/2 LS g,sg M8-B-la Bt 15-30 lOYR 4/2 LS g, sg M8-A-2a A 0-15 lOYR 4/2 LS g,sg M8-B-2a Bt 15-30 lOYR 4/2 LS g,sg M9-A-la A 0-10 lOYR 4/3 SCL g,sg M9-B-la Bt 10-30 lOYR 4/2 SCL lrn,sbk 172 b Sample Horizon Depth Color Texture a Structure M9-A-2a A 0-10 lOYR 4/3 SCL g, sg M9-B-2a Bt 10-30 lOYR 4/2 SCL lm, sbk MlO-A-la A 0-10 lOYR 4/3 LS g, sg MlO-B-la Bw 10-30 lOYR 5/2 SL m Ml0-A-2a A 0-10 lOYR 4/3 LS g, sg Ml0-B-2a Bw 10-30 lOYR 5/2 SL m Mll-A-la A 0-17 lOYR 6/3 Si CL lm, sbk Mll-B-la Bt 17-30 lOYR 7/2 SiCL lm, sbk Mll-B-lb Bt 17-30 lOYR 7/2 Si CL lm, sbk Mll-A-2a A 0-17 lOYR 6/3 Si CL lm, sbk Mll-B-2a Bt 17-30 lOYR 7/2 Si CL lm, sbk Ml2-A-la A 0-17 lOYR 5/4 SCL g,sg Ml2-B-la Bt 17-35 lOYR 4/4 CL g, sg Ml2-A-2a A 0-17 lOYR 5/4 SCL g, sg Ml2-B-2a Bt 17-35 lOYR 4/4 CL g,sg Ml3-A-la A 0-15 lOYR 6/3 SCL g,sg M13-B-la Bt 15-35 lOYR 6/2 SCL 2m, sbk Ml3-A-2a A 0-15 lOYR 6/3 SCL g,sg M13-B-2a Bt 15-35 lOYR 6/2 SCL 2m, sbk M14-A-la A 0-5 SYR 4/2 c g, sbk Ml4-B-la Bt 5-30 SYR 3/3 c 3m, sbk Ml4-A-2a A 0-5 SYR 4/2 c g,sg M14-B-2a Bt 5-30 5YR 3/3 c 3m,sbk Ml5-A-la A 0-15 lOYR 6/2 Si CL lm, sbk M15-B-la Bt 15-35 lOYR 6/2 Si CL 2m, sbk Ml5-B-lb Bt 15-35 lOYR 6/2 Si CL 2m, sbk Ml5-A-2a A 0-15 lOYR 6/2 Si CL lm, sbk Ml5-B-2a Bt 15-35 lOYR 6/2 SiCL 2m, sbk Ml6-A-la A 0-17 lOYR 5/4 SCL lm,sbk Ml6-B-la Bt 17-35 lOYR 4/4 SCL 2m,sbk Ml6-A-2a A 0-17 lOYR 5/4 SCL lm,sbk Ml6-B-2a Bt 17-35 lOYR 4/4 SCL 2m, sbk M17-A-la A 0-10 lOYR 5/3 SL g, sg Ml7-B-la Bt 10-35 7. 5YR 4/3 SL g,sg Ml7-A-2a A 0-10 lOYR 5/3 SL g, sg Ml7-B-2a Bt 10-35 7. 5YR 4/3 SL g, sg Ml7-B-2b Bt 10-35 7.5YR 4/3 SL g, sg Ml8-A-la A 0-5 7.SYR 4/2 LS g, sg Ml8-B-la Bw 10-35 7. 5YR 5/2 LS g,sg Ml8-A-2a A 0-5 7. 5YR 4/2 LS g, sg Ml8-B-2a Bw 10-35 7. 5YR 5/2 LS g, sg Ml9-A-la A 0-3 7. 5YR 4/3 LS g, sg M19-B-la Bt 5-35 7. 5YR 5/2 SL lm, sbk Ml9-A-2a .u. 0-3 7.5YR 4/3 LS g, sg Ml9-B-2a Bt 5-35 7. 5YR 5/2 SL lm,sbk 173 b Sample Horizon Depth Color Texture a Structure M20-A-la A 0-5 lOYR 3/3 LS g,sg M20-B-la Bt 5-40 lOYR 5/6 LS g.sg M20-A-la A 0-5 lOYR 3/3 LS g,sg M20-B-2a Bt 5-40 lOYR 5/6 LS g,sg M21-A-la A 0-5 7.SYR 5/3 LS g,sg M21-B-la Bt 5-40 lOYR 5/6 LS g,sg M21-A-la A 0-5 7.SYR 5/3 LS g,sg M21-B-2a Bt 5-40 lOYR 5/6 LS g,sg M22-A-la A 0-8 lOYR 4/3 LS g,sg M22-B-la Bt 8-50 lOYR 6/6 LS g,sg M22-A-2a A 0-8 lOYR 4/3 LS g,sg M22-B-2a Bt 8-50 lOYR 6/6 LS g,sg M23-A-la A 0-3 lOYR 3/3 LS g,sg M23-B-la Bw 3-40 lOYR 4/3 LS g,sg M23-A-2a A 0-3 lOYR 3/3 LS g,sg M23-B-2a Bw 3-40 lOYR 4/3 LS g,sg M24-A-la A 0-5 lOYR 3/3 LS g,sg M24-B-la Bt 20-50 lOYR 4/3 LS g,sg M24-A-2a A 0-5 lOYR 3/3 LS g,sg M24-B-2a Bt 20-50 lOYR 4/3 LS g,sg Pl Bw 15-45 lOYR 6/2 SiL lm,sbk P2 Cox 25-37 SYR 3/2 gSL m P3 B 10-15 lOYR 6/6 gSL 2m, sbk P4 B 25-37 10Y4 5/4 SiL lm, sbk PS B 30-45 lOYR 6/4 SiL 2m, sbk P6-A-la A 0-25 lOYR 3/3 SiL g,m P6-B-la Bw 25-45 lOYR 5/3 SiL lm, sbk P7-B-la A 0-20 lOYR 3/3 SiL g P7-B-la Bw 20-50 lOYR 5/3 SiL lm,sbk P8-A-la A 0-20 5YR 3/3 Si CL g,m P8-B-la Bw 20-45 7 .SYR 4/6 CL 2m, sbk P9-A-la A 0-20 5YR 3/3 Si CL g,m P9-B-la Bt 20-50 7. 5YR 5/8 CL 2m, sbk PlO-A-la A 0-30 lOYR 5/3 Si CL g,sg PlO-B-la Bt 30-75 lOYR 6/4 gSiCL sk Pll-A-la A 0-8 lOYR 4/3 SL g,sg Pll-C-la c 8-30 lOYR 6/3 s g,sg Pl2-A-la A 0-10 lOYR 3/3 Si SL m Pl2-B-la Bw 10-35 lOYR 4/3 Si SL m Pl3-A-la A 0-12 7.5YR 3/3 SiSL g,sg P13-B-la Bw 12-35 lOYR 6/3 gSiSL sk Pl4-A-la A 0-15 lOYR 3/3 LS g,sg Pl4-C-la c 15-40 2.SYR 6/3 S g,sg PlS-A-la A 0-20 lOYR 2/2 LS g,sg PlS-B-la Bt 20-45 lOYR 6/6 gSiSL sk 174 b Sample Horizon Depth Color Texture a Structure Pl6-A-la A 0-20 lOYR 5/2 SiL g,sg Pl6-B-la Bt 20-50 lOYR 6/4 SiL 2m, sbk Pl6-C-la Cox 50-360 lOYR 6/4 Si lm,sbk Pl7-A-la A 0-30 lOYR 6/2 SiL g Pl7-B-la Bw 30-75 lOYR 7/2 SiL lm, sbk Pl7-C-la c 75-100 2. 5YR 8/2 SiL lm, sbk Pl8-A-la A 0-20 7.5YR3/3CL g,m Pl8-B-la Bt 20-100 7.5YR5/6CL g,m Sl Cox 0-180 lOYR 7/4 SiC 3m, sbk S2-A-la A 0-20 7.SYR 4/3 L g,m S2-B-la Bw 20-35 7. SYR 4/4 gL sk S3-A-la A 0-20 7. SYR 4/4 L g,m S3-B-la Bw 20-35 7. SYR 5/3 gL sk 84 0-30 lOYR 4/3 SiC 2m,sbk SS-A-la A 0-30 lOYR 4/3 CL g,m S5-B-la Bw 30-65 lOYR 5/3 CL lm, sbk SS-A-lb A 0-30 lOYR 4/3 CL g,m S5-B-lb Bw 30-65 lOYR 5/3 CL lm, sbk S6-A-la A 0-30 7. 5YR 4/4 CL lm, sbk S6-B-la Bt 30-45 7. SYR 4/6 CL lm,sbk S6-A-lb A 0-30 7. 5YR 4/4 CL lm, sbk S6-B-lb Bt 30-45 7.SYR4/6CL lm, sbk S7-A-la A 0-15 lOYR 5/2 LS g,m S7-B-la c 15-25 lOYR 5/2 s g,sg S7-A-lb A 0-15 lOYR 5/2 LS g,m 87-B-lb c 15-25 lOYR 5/2 s g, sg 88-A-la A 0-8 lOYR 5/3 SL g,m S8-B-la Bw 8-35 lOYR 6/3 gSL sk SB-A-lb A 0-8 lOYR 5/3 SL g,m 88-B-lb Bw 8-35 lOYR 6/3 gSL sk S9-A-la A 0-20 lOYR 5/3 SL g,m S9-B-la c 20-30 lOYR 5/2 s g,m S9-A-lb A 0-20 lOYR 5/3 SL g,m 89-B-lb c 20-30 lOYR 5/2 s g,m 810-A-la .~ 0-15 7.5YR 4/4 CL lm,sbk SlO-B-la Bt 15-600 7. 5YR 5/4 C 3m, sbk SlO-A-lb A 0-15 7. 5YR 4/4 CL lm, sbk SlO-B-lb Bt 15-600 7. 5YR 5/ 4 C 3m, sbk Sll-A-la A 0-15 5YR 4/3 CL g,m Sll-B-la Bt 12-600 5YR 5/6 c 3m,sbk Sll-A-lb .~ 0-15 5YR 4/3 CL g,m Sll-B-lb Bt 12-600 5YR 5/6 c 3m, sbk Sl2-A-la A 0-5 lOYR 6/2 SiL g,m Sl2-B-la Bw 5-35 lOYR 6/3 SiL g,m Sl2-A-lb A 0-5 lOYR 6/2 SiL g,m 175 Sample Horizon Depth Color Texture a Structure b Sl2-B-lb Bw 5-35 lOYR 6/3 SiL g,m Wl-A-la A 0-25 lOYR 4/2 SiL g,m Wl-B-la Bg 25-45 lOYR 5/2 SiC 2m,sbk Wl-A-2a A 0-25 lOYR 4/2 SiL g,m Wl-B-2a Bg 25-35 lOYR 5/2 sic 2m, sbk W2-A-la A 0-22 lOYR 5/2 L lm, sbk W2-B-la B 22-45 lOYR 5/4 SiC 2m, sbk W2-A-2a A 0-22 lOYR 5/2 L lm, sbk W2-B-2a B 22-45 lOYR 5/4 sic 2m, sbk W3-A-la A 0-25 lOYR 5/3 SiL g,m W3-B-la Bw 25-60 lOYR 5/4 Si CL lm, sbk W3-A-2a A 0-25 lOYR 5/3 SiL g,m W3-B-2a Bw 25-60 lOYR 5/4 Si CL lm,sbk W4-A-la A 0-30 lOYR 5/2 L g W4-B-la Bw 30-58 lOYR 5/2 Si CL lm, sbk W4-A-2a A 0-30 lOYR 5/2 L g W4-B-2a Bw 30-45 lOYR 5/2 Si CL lm, sbk WS-A-la A 0-40 lOYR 4/3 L g WS-B-la Bt 40-55 lOYR 4/6 c 2m,sbk WS-A-2a A 0-40 lOYR 4/3 L g W5-B-2a Bt 40-55 lOYR 4/6 c 2m,sbk W6-A-la A 0-22 lOYR 6/4 SiC g,m W6-B-la BC 22-35 lOYR 6/3 c 2rn,sbk W6-A-2a A 0-22 lOYR 6/4 SiC g,m W6-B-2a BC 22-30 lOYR 6/3 c 2m, sbk W7-A-la A 0-60 7.SYR 4/4 SiCL g,m W7-B-la Bt 60-120 7.5YR 5/6 c 3m,sbk W8-A-la A 0-45 7.5YR 5/4 Si CL g,m W8-B-la Bt 45-150 7.5YR 5/4 c 3m, sbk W9-A-la A 0-20 lOYR 5/3 SiL g,m W9-B-la Bw 20-50 lOYR 6/3 Si CL g,m a Key to soil texture - C: clay, g: gravelly, L: loam, S: sand, Si: silt. b Key to soil structure - g: granular, m: massive (modifiers 1,2,3 refer to weak, medium and strong respectively); sbk: subangular blocky, sg: single grain, sk: skeletal. From Birkeland and others, 1991. * Time constraints prohibited analyzing many of the A soil horizons. v~va 3GI~JflNOICTuCI ~IOS 8 XIGN3ddV 9l1 Sample Ac22s % error Bi 214 % error Csl37 a % error K~o b % error Th2n b % error Missoula Flood sediments (coarse grained facies) Pl 38.2 4.6 41. 0 3.8 7.9 8.1 500.7 2.2 34.1 4.3 P2 31. 6 5.7 35.7 5.1 4.2 12.0 473.9 2.8 26.8 4.4 l P3 40.0 6.7 43.7 4.5 2.7 nd 583.5 2.4 32.1 4.4 Pl5-B-la 29.3 4.9 33.7 4.1 1. 8 nd 434.1 2.6 29.6 3.1 l Missoula Flood sediments (fine grained facies) C2-B-lb 38.1 5.8 38.6 3.9 1.4 28.0 660.1 2.0 32.5 3.7 C2-B-2a 42.0 5.7 50.3 5.0 3.0 16.9 758.5 2.1 39.0 3.3 l P4 31. 5 6.4 43.2 3.9 5.0 10.2 551.9 2.6 30.0 3.7 PS 33.3 6.5 42.6 3.6 4.1 14.9 570.0 2.2 30.5 3.3 l 812-B-la 39.8 5.0 37.2 3.5 4.6 11. 9 492.0 2.2 34.3 3.2 l 812-B-lb 40.1 6.3 34.0 6.3 4.1 16.5 459.3 3.5 36.6 4.7 W2-B-la 41.9 9.4 35.4 5.6 3.7 nd 452.7 3.7 37.1 4.5 l W2-B-2a 34.3 8.5 30.3 7.0 3.7 nd 429.0 3.4 32.5 4.4 W3-B-la 30.9 6.2 31. 3 4.0 2.4 15.3 516.3 2.3 30.8 3.8 W3-B-2a 32.5 15.1 37.0 5.8 bd nd 497.4 4.5 28.8 8.3 W9-A-la 34.2 9.5 40.5 5.8 18.9 5.9 587.8 3.5 32.2 6.4 W9-B-la 33.2 7.7 37.7 5.4 6.1 14.5 567.7 3.3 34.3 4.3 l Clackamas River terraces P8-B-la 17.3 6.1 18.6 4.9 4.0 nd 53.0 5.0 17.5 2.8 2, 3 P9-B-la 25.5 6.1 28.8 4.8 bd nd 87.9 5.0 25.4 3.9 2, 3 PlO-B-la 24.0 6.4 25.9 5.0 1. 8 21. 3 227.3 3.2 24.3 3.4 2' 3 P12-B-la 13.2 11.2 17.0 7.4 4.5 10.5 265.7 3.2 14.7 3.7 2,3 t--1 .....J .....J Ac22a Sample % Bi 214 Cs131 a K.;o b b error % error % error % error Th232 % error Portland Hills silt (loess) Cl-B-la 36.8 5.2 40.1 4.1 3.9 13.8 525.6 2.2 32.7 3.2 Cl-B-2a 31. 7 8.3 42.0 4.4 2.5 21. 3 518.3 2.3 30.5 4.2 P6-B-la 32.6 4.9 34.6 4.7 8.8 7.5 434.2 2.6 31. 2 3.2 P7-B-la 28.6 7.7 34.4 5.7 12.5 9.1 452.9 3.0 30.0 6.3 Pl6-A-la 26.9 7.5 29.6 5.1 22.2 4.4 438.3 2.4 29.1 3.2 P16-B-la 31. 0 4.9 32.5 3.9 bd nd 427.9 2.2 30.2 3.1 P16-C-la 30.3 5.7 30.1 6.6 bd nd 423.7 2.5 30.0 4.2 Linn Gravels SB-B-la 25.5 9.9 24.6 6.4 4.5 5.0 384.3 3.9 22.3 6.4 S8-B-lb 17.5 22.9 5.0 1. 8 4.8 399.2 2.6 21. 8 4.4 Willamette River sediment S7-B-la 19.7 7.5 17.2 66.4 2.2 24.3 428.1 2.0 15.5 5.8 S7-B-lb 18.1 7.0 20.1 5.1 2.0 22.6 421.5 2.5 16.5 5.6 S9-B-la 15.8 7.1 16.9 5.9 7.9 6.6 357.4 2.6 14.6 4.4 S9-B-lb 17.1 19.8 18.4 6.2 8.5 8.7 373.7 3.3 15.9 7.5 Wl-B-la 27.5 6.6 24.2 5.6 bd nd 252.9 4.8 24.2 5.8 Wl-B-2a 27.0 9.4 34.6 5.1 5.2 14.4 282.3 4.4 26.1 6.5 W4-B-la 18.6 7.6 21. 0 4.6 2.1 nd 313. 0 2.8 15.2 6.0 W4-B-2a 13. 0 5.0 15.7 6.3 bd nd 303.3 3.3 16.5 6.0 t-J ....J CD Sample Ac22a % error Bi 214 % error Csl37 a % error K4o b % error Th232 b % error Mixed Columbia/Willamette River sediment P14-C-la 23.7 7.6 24.9 4.9 3.2 nd 494.3 2.2 21.2 4.5 Clackamas River sediment Pll-C-la 12.9 14.0 15.7 6.1 3.7 13 .o 212.3 3.3 11.6 5.3 Columbia River Drainage basin system Troutdale Formation P13-B-la 33.9 7.5 37.0 4.6 10.9 8.7 514.2 2.6 32.6 3.3 Pl 7-A-la 34.9 7.1 42.3 5.6 2.5 24.1 573.7 3.1 34.2 4.3 Pl7-B-la 34.9 9.2 44.6 5.8 bd nd 593.5 3.5 44.2 4.0 Pl7-C-la 39.4 6.7 45.4 5.5 bd nd 535.1 3.2 38.8 4.2 Columbia River basalt (Grande Ronde) Eola Hills Sl 26.0 4.8 23.0 1. 9 0.1 1. 7 364.0 6.8 nd nd 82-B-la 26.9 5.5 30.7 3.9 5.1 11. 2 289.6 2.8 25.0 4.3 83-B-la 33.3 3.8 21.1 2.0 4.3 4.5 155.9 1. 6 nd nd 84 26.5 8.2 28.2 5.8 1.1 5.6 268.1 3.4 26.2 4.4 85-B-la 30.4 4.9 24.1 4.7 bd nd 218.0 3.4 27.6 3.0 85-B-lb 26.6 5.7 22.2 4.3 bd nd 204.1 3.5 25.2 3.2 86-B-la 35.2 5.1 28.3 3.8 1. 3 6.2 151.8 4.1 34.5 3.4 86-B-lb 38.3 4.9 40.2 3.4 2.3 5.0 154.7 4.6 35.8 3.5 Salem Hills SlO-B-la 28.1 8.2 27.4 5.5 bd nd 129.9 5.8 27.8 3.7 810-B-lb 27.6 5.9 30.2 3.8 bd nd 140.6 4.8 28.6 3.3 ~ ...... ] \.,0 Ac22a Bi 214 Cs137 a Sample % error % error % error K4o b % error Th232 b % error Sll-B-la 28.7 5.4 30.6 4.3 bd nd 954.6 5.6 29.5 3.4 Sll-B-lb 30.0 9.4 31.1 4.7 bd nd 882.7 6.7 30.1 3.9 Parrett Mountain W7-A-la 37.3 7.2 39.0 6.2 2.7 5.9 309.1 4.6 29.7 6.6 W7-B-la 29. 4 8.5 35.2 5.3 bd nd 222.3 4.3 30.8 4.0 W8-A-la 30.6 7.6 35.0 5.9 2.3 69.8 382.6 4.6 29.2 4.8 W8-B-la 31. 0 6.6 34.2 4.2 1. 3 31. 5 315.1 3.1 31. 0 3.0 Banks Columbia River basalt (flow unknown) C3-B-la 45.8 5.2 47.0 4.9 bd nd 313 .4 3.5 43.3 2.9 C3-B-2a 47.6 5.5 52.7 3.4 bd nd 208.2 3.5 49.3 2.6 Portland area Boring Lava Pl8-B-la 30.9 6.8 36.7 4.6 bd nd 331.9 3.3 32.8 3.4 6 Tillamook Volcanics C8-B-la 13.5 8.9 20.3 6.9 8.0 6.7 268.4 3.4 15.1 5.1 C8-B-2a 17.6 6.7 18.4 7.1 6.9 7.0 377.1 2.7 16.8 5.6 C12-B-la 32.8 6.7 21. 7 7.5 1. 0 2.0 323.7 3.8 26.6 6.1 C12-B-2a 25.8 8.4 20.9 5.2 4.6 3.4 314.1 3.8 23.0 4.1 Siletz River Volcanics Cl3-A-la 14.1 6.6 17.9 5.0 0.9 2.9 114.7 4.5 12.7 4.4 C13-B-la 11.4 0.0 15.7 5.8 bd nd 143.8 0.0 13.8 4.1 6,7 Cl6-A-la 16.0 6.4 16.0 5.8 1. 0 35.8 169.0 0.0 17.4 4.4 r1 CX> 0 -··-~------·---~·-··------Ac22s Bi214 Cs131 a K4o b Sample % error % error % error % error Th232 b % error 6 7 Cl6-B-la 8.9 13.5 5.1 0.0 bd nd 157.5 4.1 6.2 12.3 ' Cl6-C-la 7.6 9.5 6.2 8.8 bd nd 230.3 3.6 5.9 7.7 Maf ic intrusives ClO-B-la 29.7 7.2 40.3 4.4 8.9 7.9 248.0 4.2 31. 6 3.5 Cl0-B-2a 27.0 6.3 33.3 4.5 2.5 5.5 258.3 4.2 30.2 3.9 Tyee Formation Cl4-A-la 26.4 7.1 31. 8 4.4 1. 9 19.6 475.3 2.3 26.6 3.3 Cl4-B-la 34.8 7.6 33.0 5.5 11. 7 43.8 491.9 2.6 34.3 3.1 Cl5-A-la 28.4 6.7 26.0 6.0 1. 9 23.2 454.8 2.7 29.3 3.4 Cl5-B-la 32.8 5.0 26.9 5.9 bd nd 376.4 3.1 33.7 3.4 C15-C-la 29.4 5.2 22.7 7.0 bd nd 656.2 1. 8 29.7 3.5 Cowlitz Formation C6-B-la 34.1 6.6 44.9 5.0 4.8 10.3 494.0 2.9 34.7 2.9 C6-B-2a 36.0 7.4 35.3 6.6 4.4 8.9 486.4 4.0 34.3 4.6 C9-B-la 34.9 9.0 51. 7 4.7 3.1 27.9 352.9 4.3 33.1 6.1 C9-B-2a 38.5 6.8 47.S 4.3 8.2 13.7 410.5 3.5 37.7 5.0 W6-B-la 29.2 7.0 21. 3 5.3 1. 8 5.8 457.8 2.6 27.9 4.3 W6-B-2a 28.0 6.0 18.2 5.9 6.4 11.1 407.5 2.6 26.7 5.2 Yamhill Formation W5-B-la 25.9 5.0 19.8 4.2 bd nd 242.5 3.2 21. 4 5.1 W5-B-2a 26.9 6.2 16.8 6. 7 bd nd 222.4 3.8 23.2 4.1 ~-I Q) }-I Sample Ac22a Bi 214 Csl37 a K4o b % error % error % error % error Th232 b % error Keasey Formation C5-B-la 30.4 5.7 41. 0 4.4 6.3 7.6 485.2 2.9 28.5 4.3 C5-B-2a 38.3 7.8 41.1 5.8 3.6 34.8 515.6 4.1 34.3 4.7 C7-B-la 26.8 8.4 42.6 4.1 6.0 9.8 595.1 2.2 28.3 3.8 C7-B-2a 29.8 6.8 42.2 4.5 9.8 7.0 623.3 2.5 29.8 5.2 Pittsburg Bluff Formation C4-B-la 36.0 7.4 55.8 4.0 bd nd 373.1 3.1 36.9 3.5 C4-B-2a 39.3 5.0 46.5 3.1 0.7 45.9 206.6 3.3 34.4 4.0 Mixed marine and volcanic sediment Cll-B-la 28.2 7.1 33.9 4.7 2.8 5.0 174.9 4.4 30.4 3.5 Cll-B-2a 36.7 7.1 33.1 5.6 3.6 31. 4 215.9 5.3 33.6 4.5 Cascadian air fall volcanic ash Mll-B-la 24.1 6.4 28.5 5.0 2.2 5.0 378.1 2.7 19.9 4.4 3,9 Mll-B-lb 21. 9 5.1 17.7 2.1 2.8 6.0 341.9 1. 0 nd nd Mll-B-2a 29.7 6.3 25.3 4.8 bd nd 414.2 2.8 26.0 5.3 3' 9 M15-B-la 46.2 5.2 43.3 4.0 bd nd 604.9 2.2 42.0 2.6 3,9 M15-B-lb 42.2 3.4 25.9 1. 8 bd nd nd nd nd nd 3,10 Ml5-B-2a 48.4 9.7 47.9 4.7 5.2 17.1 660.4 0.0 45.9 3.8 3,9 Cascadian volcanic ash and water laid mixed ash and tuf f M16-B-la 25.4 6.7 31. 0 4.8 5.2 9.6 431.8 2.5 22.5 5.0 3' 9 M16-B-2a 27.9 8.8 27.2 5.4 8.4 8.6 445.4 2.4 26.0 4.0 3' 9 Ml2-B-la 20.0 5.7 26.4 4.9 3.4 12.9 341. 9 2.8 18.4 6.5 3' 9 t-..a (X) tv Sample Ac22e % error Bi 214 % error Csl37 a % error K4o b % error Th232 b % error M12-B-2a 26.3 5.7 24.9 5.0 0.0 0.0 304.7 3.6 21. 6 4.2 3. 9 Ml3-B-la 24.3 5.7 24.7 6.0 5.0 12.0 336.5 2.7 21. 3 4.1 3,9 M13-B-2a 20.1 6.4 22.3 4.5 2.9 17.4 265.8 3.9 18.7 5.1 3,9 3,9 MlO-B-la 11.4 9.6 18.1 5.4 8.0 5.9 366.6 2.9 11. 9 7.9 3,9 M10-B-2a 11. 3 9.7 16.8 6.0 2.0 14.0 387.4 2.6 11. 2 4.8 3,9 M8-B-la 10.4 11.4 13 .0 10.2 1. 5 0.0 395.1 2.6 10.9 4.6 M8-B-2a 12.3 6.6 15.8 6.1 5.4 9.7 420.3 2.5 10.8 6.8 3,9 3,9 M9-B-la 15.6 10.8 21. 2 5.4 4.7 9.1 302.8 2.9 13. 7 5.1 M9-B-2a 16.5 7.3 19.3 6.2 5.0 7.8 305.4 2.9 14.1 6.9 3,9 Cascadian volcanics (undifferentiated flows, alluvium, colluviurn and glacial deposits) Ml-B-la 15.5 6.9 17.7 7.6 5.8 8.0 268.0 3.3 12.5 4.4 Ml-B-2a 12.2 9.9 17.9 5.9 7.9 6.5 273.6 3.5 15.9 5.6 M2-B-la 13.4 7.6 15.3 9.8 bd nd 203.5 3.8 11. 9 5.8 M2-B-2a 14.4 10.2 16.8 8.3 1. 2 5.1 238.6 4.0 14.5 5.3 M3-B-la 13.6 9.9 20.9 5.1 5.7 7.9 406.2 2.8 11. 7 7.8 M3-B-lb 11.3 13.0 17.7 6.5 1.1 4.8 369.8 2.6 12.0 5.1 M4-B-la 15.4 6.5 17.6 6.6 1.2 16.5 343.2 3.1 13 .4 5.3 M4-B-2a 13.7 10.2 17.8 6.3 bd nd 299.8 3.0 12.3 7.0 M5-B-la 12.3 12.8 20.6 4.9 2.0 20.0 378.5 2.6 12.8 5.0 M5-B-2a 17.0 7.7 17.1 7.2 5.7 7.6 298.2 3.1 13.9 7.5 M7-B-la 16.8 7.9 19.1 11.0 7.4 8.5 241.5 3.3 16.7 4.3 M7-B-2a 16.9 8.1 21. 6 6.0 1.2 4.9 255.9 3.3 16.6 4.7 M6-B-la 16.8 5.6 21.2 5.1 2.2 13 .8 310.3 3.1 14.3 4.9 I-> en w Sample Ac22s % error Bi 214 % error Csl37 a % error K4o b % error Th232 b % error M6-B-2a 17.5 9.1 22.3 4.8 3.9 9.9 341.1 2.9 16.4 4.7 Ml4-B-la 11.3 8.9 17.8 5.0 3.4 9.5 207.3 3.2 10.2 5.1 Ml4-B-2a 11.1 7.8 15.3 4.8 2.1 15.7 252.3 2.8 9.9 5.8 Ml7-B-la 21. 5 5.5 24.8 5.2 1. 0 6.2 267.0 5.0 18.3 5.0 Ml7-B-2a 23.9 5.9 25.3 5.0 bd nd 274.2 3.2 21. 7 3.8 M17-B-2b 19.4 5.1 13.1 2.4 1.7 8.8 237.6 1. 2 nd nd Ml8-B-la 23.2 8.5 21. 2 5.5 8.4 8.4 293.9 3.0 24.1 5.6 Ml8-B-2a 19.9 10.8 26.7 4.7 1. 6 4.8 287.4 3.2 20.5 3.8 Ml9-B-la 15.5 9.2 16.1 5.7 1.4 4.8 281.0 3.3 12.1 9.2 Ml9-B-2a 20.6 15.5 21. 7 5.3 1.0 7.5 268.8 3.3 23.1 5.4 M20-B-la 13. 5 6.9 18.4 5.9 1. 3 4.6 256.0 3.7 10.3 5.0 M20-B-2a 15.1 7.6 14.2 7.0 1. 2 5.0 243.0 3.4 11. 3 5.7 M21-B-la 12.0 9.0 12.5 6. 5 6.1 8.6 176.6 5.0 8.4 7.9 M21-B-la* 13. 5 8.8 11. 4 3.2 8.9 2.8 224.5 1. 5 nd nd M21-B-2a 12.8 10.2 10.5 7.8 6.2 10.6 219.5 4.5 9.6 5.9 M22-B-la 10.4 10.0 9.8 6.9 6.2 6.1 158.3 4.0 5.3 5.0 M22-B-2a 6.9 9.6 7.6 7.2 6.4 5.8 147.4 4.2 5.8 8.2 M23-B-la 7.1 9.3 8.6 8.3 3.8 7.0 95.4 0.0 5.1 6.7 M23-B-2a 5.9 16.6 8.8 9.8 5.6 9.1 157.6 5.3 5.6 7.4 M24-B-la 7.2 11. 5 8.9 5.6 2.8 8.9 131.7 4.0 5.7 10. 0 3 M24-B-2a 4.5 10.0 4.5 14.0 4.5 6.7 152.3 3.6 4.0 10. 6 3 137 a - bd for Cs data means below detection, nd - bad photo peak for establishing counting error. b nd for K40 and Th 232 means no data. - Undifferentiated Missoula Flood sediments. - Clackamas River terraces (Table XIII) . !---' CX> .t::- - Cascade Range soils (Table VII) . - Soil horizons used in Table X. - Inceptisols (Table XVII) . - Ultisols (Table XVI) . 7 - Samples used in Table VI - Soil horizons used in Table VIII - Samples used in Table XII. 10 - Questionable data. duplicate sample analysed by Acadiana Research Laboratory. ~ CD V1 186 APPENDIX C OREGON DEPARTMENT OF HUMAN RESOURCES, HEALTH DIVISION. INDOOR RADON DATA, MAY, 1994 Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97005 2.0 195.20 12/17/88 03/22/89 94 c BEAVERTON WASHINGTON 97005 1.1 108.30 05/16/89 08/21/89 97 E BEAVERTON WASHINGTON 97005 0.7 79.10 03/05/89 06/15/89 102 E BEAVERTON WASHINGTON 97005 0.2 19.00 01/28/90 04/29/90 91 I BEAVERTON WASHINGTON 97005 2.4 991.10 12/18/88 01/29/90 406 A BEAVERTON WASHINGTON 97005 0.3 48.80 12/19/89 05/14/90 146 J BEAVERTON WASHINGTON 97005 2.4 425.50 03/05/90 08/27/90 175 B BEAVERTON WASHINGTON 97005 0.4 233.90 03/06/89 07/01/90 482 c BEAVERTON WASHINGTON 97005 2.6 879.20 06/19/89 05/19/90 334 B BEAVERTON WASHINGTON 97005 1. 4 558.60 05/21/88 05/30/89 373 z BEAVERTON WASHINGTON 97005 3.6 1328. 60 04/15/89 04/19/90 369 A BEAVERTON WASHINGTON 97005 1. 5 145.90 01/13/90 04/17/90 94 E BEAVERTON WASHINGTON 97005 3.7 19.50 02/15/89 02/20/89 5 A BEAVERTON WASHINGTON 97005 2.0 295.90 12/18/89 05/12/90 145 c BEAVERTON WASHINGTON 97005 0.4 204.60 05/22/88 07/12/89 415 A BEAVERTON WASHINGTON 97005 1. 2 587.70 05/24/88 08/23/89 455 B BEAVERTON WASHINGTON 97005 0.8 369.50 04/08/88 06/25/89 442 A BEAVERTON WASHINGTON 97005 1. 3 119.00 02/27/89 05/29/89 91 z BEAVERTON WASHINGTON 97005 0.9 88.40 01/08/90 04/10/90 92 L BEAVERTON WASHINGTON 97005 1. 4 117. 40 01/08/89 04/01/89 83 c BEAVERTON WASHINGTON 97005 0.6 508.30 05/09/88 08/22/90 834 B BEAVERTON WASHINGTON 97005 1.3 144.90 01/21/89 05/08/89 107 F BEAVERTON WASHINGTON 97005 1. 3 125.70 01/21/90 04/21/90 90 c BEAVERTON WASHINGTON 97005 1. 7 627.40 06/13/88 06/15/89 366 H BEAUERTON WASHINGTON 97005 0.3 108.90 03/21/89 12/30/89 284 c BEAVERTON WASHINGTON 97005 0.6 252.00 04/10/89 04/12/90 367 A BEAVERTON WASHINGTON 97005 0.9 383.10 12/18/88 01/29/90 406 D BEAVERTON WASHINGTON 97005 1.1 420.50 04/25/89 04/18/90 358 A BEAVERTON WASHINGTON ~ OJ .....J Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97005 0.5 197.70 12/08/88 11/14/89 340 B BEAVERTON 970H 1.4 WASHINGTON 151.80 04/22/90 08/08/90 108 D LAKE OSWEGO CLACKAMAS 970H 1.9 721.10 10/08/88 10/04/89 360 A LAKE OSWEGO CLACKAMAS 970H 5.8 2167.50 12/05/88 12/09/89 368 A LAKE OSWEGO CLACKAMAS 970H 0.6 253.30 04/01/89 04/01/90 365 E LAKE OSWEGO CLACKAMAS 97034 1.2 441.40 05/05/88 05/01/89 360 J LAKE OSWEGO CLACKAMAS 97034 0.2 22.30 02/28/89 05/30/89 91 B LAKE OSWEGO CLACKAMAS 97034 0.5 45.90 01/21/90 04/21/90 90 F LAKE OSWEGO 97034 0.8 76.90 CLACK.AMAS 11/05/89 01/30/90 86 c LAKE OSWEGO CLACKAMAS 97034 0.3 115.60 01/21/89 01/22/90 366 D LAKE OSWEGO 97034 4.2 1594.50 CLACK.AMAS 09/04/89 374 970H 09/13/90 A LAKE OSWEGO CLACKAMAS 6.0 2208.60 02/21/89 02/19/90 363 A LAKE OSWEGO 970H 4.0 370.10 CLACKAMAS 01/17/90 92 04/19/90 A LAKE OSWEGO CLACK.AMAS 97034 2.6 357.30 02/20/89 07/07/89 137 A LAKE OSWEGO 97034 0.5 49.40 CLACKAMAS 02/03/90 92 05/06/90 A LAKE OSWEGO CLACK.AMAS 97034 0.1 5.60 02/01/90 89 B LAKE OSWEGO 97034 0.9 4.60 05/01/90 CLACKAMAS 04/10/89 04/15/89 5 A LAKE OS\'lEGO CLACKAMAS 97034 7.3 642.80 03/24/89 06/19/89 87 A 97034 LAKE OSWEGO CLACKAMAS 0.9 111.40 09/26/88 01/23/89 118 z LAKE OSWEGO CLACKAMAS 97034 0.6 67.70 01/10/90 04/17/90 97 c LAKE OS\'lEGO 97034 1.0 94.90 CLACKAMAS 02/04/90 05/06/90 91 A 97034 LAKE OSWEGO CLACKAMAS 8.4 753.40 01/14/90 04/13/90 89 z LAKE OSWEGO CLACKAMAS 97034 7.5 678.60 11/09/89 02/07/90 90 A 97034 LAKE OSWEGO CLACKAMAS 3.7 1401.70 11/09/89 11/05/88 368 A LAKE OSWEGO CLACKAMAS 97034 1. 2 111.10 03/11/89 06/08/89 89 LAKE OSWEGO 97034 2.6 CLACKAMAS 977. 70 04/01/89 04/01/90 365 I LAKE OSWEGO CLACKAMAS 97034 0.3 120.10 03/22/89 03/29/90 372 D 970H 2.6 LAKE OSWEGO CLACKAMAS 1008.40 05/02/88 05/20/89 382 I LAKE OSWEGO CLACKAMAS 1---J CX> CX> Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97034 4.8 512.20 04/05/89 07/19/89 105 E LAKE OSWEGO CLACKAMAS 97034 1. 2 127.10 11/12/88 02/21/89 100 A LAKE OSWEGO CLACKAMAS 97034 1.4 516.60 09/27/88 09/19/89 356 B LAKE OSWEGO CLACKAMAS CLACKAMAS 97034 1. 6 621.30 05/30/88 06/03/89 368 B LAKE OSWEGO CLACKAMAS 97034 1. 6 592.20 05/22/90 365 A LAKE OSWEGO 05/22/89 CLACKAMAS 97034 1. 8 692.20 11/05/88 11/09/89 368 D LAKE OSWEGO 97034 1. 9 126.60 03/01/89 05/05/89 65 A LAKE OSWEGO CLACKAMAS 97034 0.3 107.90 04/27/89 04/10/90 348 J LAKE OWSEGO CLACKAMAS 97034 2.0 768.80 12/14/88 12/17/89 367 A LAKE OSWEGO CLACKAMAS 97034 1. 9 177.60 01/15/90 04/15/90 90 E LAKE OSWEGO CLACKAMAS 97034 4.1 357.40 10/17/88 01/11/89 BS A LAKE OSWEGO CLACKAMAS CLACKAMAS 97034 2.4 202.30 04/24/89 82 A LAKE OSWEGO 07/15/89 CLACKAMAS 97034 2.4 1000.20 10/25/88 12/08/89 408 c LAKE OSWEGO CLACKAMAS 97034 793.30 04/09/88 03/06/89 330 A LAKE OSWEGO 2.3 CLACKAMAS 97034 2.1 215.40 06/23/90 09/29/90 98 A LAKE OSWEGO 97035 8.3 768.10 92 A LAKE OSWEGO MULTNOMAH 06/12/89 09/12/89 97035 1. 0 96.10 11/07/89 92 A LAKE OSWEGO MULTNOMAH 02/07/90 97035 1. 8 260.90 04/09/89 08/28/89 141 H LAKE OSWEGO MULTNOMAH 97035 0.6 60.80 03/20/90 06/24/90 96 A LAKE OSWEGO MULTNOMAH 97035 1. 0 395.80 04/23/89 04/23/90 365 c LAKE OSWEGO MULTNOMAH 97035 1.3 139 .10 05/08/90 08/19/90 103 G LAKE OSWEGO MULTNOMAH 97035 0.5 98.90 165 D LAKE OSWEGO MULTNOMAH 04/01/89 09/13/89 97035 0.9 114.90 12/10/88 04/09/89 119 A LAKE OSWEGO MULTNOMAH 97035 1. 7 154.70 04/26/89 07/25/89 90 E LAKE OSWEGO MULTNOMAH 97035 1. 0 5. 30 5 A LAKE OSWEGO MULTNOMAH 07/21/90 07/26/90 97035 1. 5 592. 70 04/11/88 375 D LAKE OSWEGO MULTNOMAH 1. 0 376.60 12/01/88 04/22/89 97035 12/02/89 365 c LAKE OSWEGO MULTNOMAH 97035 0.9 501.10 04/18/88 09/22/89 521 B LAKE OSWEGO MULTNOMAH ~ CD \.0 Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/ 1} Exposure days 97035 0.9 5.40 11/19/89 11/25/89 6 A LAKE OSWEGO MULTNOMAH 4.0 97035 321. so 10/22/89 01/10/90 80 A LAKE OSWEGO MULTNOMAH 97035 2.6 947.10 04/08/88 04/04/89 360 D LAKE OSWEGO MULTNOMAH 97035 3.4 1268.00 03/10/89 03/10/90 365 A LAKE OSWEGO MULTNOMAH 97035 0.6 236.40 03/26/88 03/31/89 369 D LAKE OSWEGO MULTNOMAH 0.1 97035 52.60 01/12/89 01/15/90 368 J LAKE OSWEGO MULTNOMAH 97035 0.5 212.90 01/16/90 367 01/14/89 c LAKE OSWEGO MULTNOMAH 97035 1.9 175.60 02/14/89 05/14/89 89 z LAKE OSWEGO MULTNOMAH 97035 0.1 8.60 107 A 01/18/90 05/05/90 LAKE OSWEGO MULTNOMAH 97035 4 1. 127.20 01/25/90 88 z LAKE OSWEGO MULTNOMAH 97035 0.2 04/23/90 24.80 01/16/90 91 c LAKE OSWEGO MULTNOMAH 04/17/90 97035 1.2 435.90 09/28/88 360 E LAKE OSWEGO MULTNOMAH 09/24/89 97038 1.0 416.60 04/09/88 401 B MOLALLA CLACKAMAS 97201 1.8 167.70 11/15/88 05/16/8902I13 I 8 9 89 A PORTLAND MULTNOMAH 97201 0.8 81. 20 01/13/90 04/15/90 92 E PORTLAND MULTNOMAH 97201 1. 9 945.00 04/28/88 08/14/89 472 E PORTLAND MULTNOMAH 0 97201 1. 401.70 11/27 /88 12/09/89 376 A PORTLAND MULTNOMAH 97201 2.0 667.90 07/16/88 06/11/89 329 z PORTLAND MULTNOMAH 97201 1. 0 395.20 11/27 /88 11/27/89 364 E PORTLAND MULTNOMAH 97201 2.0 266.40 09/17/89 01/22/90 127 A PORTLAND MULTNOMAH MULTNOMAH 97201 1.1 596.90 08/16/88 12/27/89 497 A PORTLAND 97201 2.9 1090.30 PORTLAND 09/26/88 10/04/89 372 J MULTNOMAH 2 PORTLAND 97201 1. 613. 40 04/26/88 08/31/89 491 A MULTNOMAH PORTLAND 97201 3.6 1187. 80 01/01/89 11/25/89 328 A MULTNOMAH PORTLAND 1. 4 146.50 04/09/89 98 MULTNOMAH 97201 01/01/89 A 4.8 3475.30 PORTLAND 97201 07/17/89 714 MULTNOMAH 97201 08/02/87 PORTLAND 1.5 137.00 04/24/90 90 A MULTNOMAH 97201 4.9 425.40 01/24/9007/10/89 10/04/89 86 I PORTLAND MULTNOMAH 1--1 \.D 0 Zip Code Concentration Total Start Date End Date Total Location a City County {pCi/l} Exposure days 97201 1. 7 652.50 02/21/89 02/20/90 364 A PORTLAND MULTNOMAH 97201 0.8 329.60 12/26/88 01/01/90 370 z PORTLAND MULTNOMAH 97201 1. 8 665.60 04/28/88 04/23/89 359 A PORTLAND f.lULTNOMAH 97201 0.7 273.20 04/17/88 04/17/89 364 E PORTLAND MULTNOMAH 97201 1.0 95.BO 11/28/88 02/28/89 91 E PORTLAND MULTUOMAH 97201 0.3 145.00 01/08/89 01/07/90 364 c PORTLAND MULTNOMAH 97201 1.1 335.90 08/14/89 06/02/90 292 A PORTLAND MULTNOMAH 97201 0.6 25.10 03/04/89 04/10/89 37 E PORTLAND MULTNOMAH 97201 1. 4 264.10 11/16/88 05/22/89 186 A PORTLAND MULTNOMAH 97201 0.5 58.70 02/08/89 05/22/89 103 z PORTLAND MULTNOMAH 97201 1. 7 158.80 04/25/89 07/23/89 89 c PORTLAND MULTllOMAH 97201 1.1 657.80 03/24/88 10/18/89 572 J PROTLAND MULTNOMAH 97201 1. 2 473.90 03/27/89 03/28/90 366 A PORTLAND MULTNOMAH 97201 1. 6 260.30 01/28/90 07/01/90 154 A PORTLAND MULTNOMAH 97201 1. 0 408.30 04/23/88 04/30/89 371 A PORTLAND MULTNOMAH 97201 0.4 170.90 11/27/88 12/16/89 383 J PORTLAND MULTNOMAH 97201 0.1 67.60 11/26/88 11/26/89 364 c PORTLAND MULTNOMAH 97201 0.2 102.90 11/27/88 12/16/89 383 c PORTLAND MULTNOMAH 97201 0.3 139.60 07/09/89 08/26/90 413 E PORTLAND MULTNOMAH 97201 0.4 80 171. 07/09/89 08/26/90 413 A PORTLAND MULTNOMAH 97201 0.2 127.60 04/09/88 07/30/89 476 E PORTLAND MULTNOMAH 97202 2.3 906.20 05/27/88 06/10/89 378 A PORTLAND MULTUOMAH 97202 1. 6 151.20 03/18/89 06/17/89 91 A PORTLAND MULTNOMAH 97202 7.5 2857.60 05/01/88 05/13/89 376 A PORTLAND MULTNOMAH 97202 3.0 1476.50 04/11/88 08/10/89 485 A PORTLAND MULTNOMAH 97202 2.7 1019.40 03/12/89 03/12/90 365 A PORTLAND MULTNOMAH 97202 1. 6 640.70 04/16/88 05/02/89 380 A PORTLAND MULTNOMAH 97202 2.6 236.40 02/17/89 05/18/89 90 c PORTLAND MULTNOMAH f.-J \..0 f.-J Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97202 3.1 318. 30 02/24/90 06/04/90 100 A PORTLAND MULTNOMAH 97202 2.8 1077. 00 05/02/88 05/10/89 372 A PORTLAND MULTNOMAH 97202 2.2 910. so 05/07/88 06/08/89 396 A PORTLAND MULTNOMAH 97202 3.2 1187.30 09/11/88 09/10/89 363 A PORTLAND MULTNOMAH 97202 1. 5 10.80 06/18/90 06/25/90 7 A PORTLAND MULTNOMAH 97202 2.9 1071.10 10/10/88 10/10/89 364 A PROTLAND MULTNOMAH 97202 2.0 183.60 03/04/90 06/03/90 91 A PORTLAND MULTNOMAH 97202 5 1. 579.30 03/23/89 03/25/90 367 A PORTLAND MULTNOMAH 97202 2.5 1104. 00 04/25/88 07/09/89 439 z PORTLAND MULTNOMAH 97202 1. 6 622.60 07/29/89 08/14/90 381 A PORTLAND MULTNOMAH 97202 3.4 20.20 01/20/90 01/26/90 6 A PORTLAND MULTNOMAH 97202 3.7 1375.80 10/04/88 10/04/89 364 A PORTLAND MULTNOMAH 97202 1.2 127.80 02/26/90 06/07/90 101 A PORTLAND MULTNOMAH 97202 1.0 369.80 11/27 /88 11/27 /89 364 A PORTLAND MULTNOMAH 97202 2.4 221.30 08/27/89 11/27 /89 92 A PORTLAND MULTNOMAH 97202 3.8 1424.70 05/01/88 05/03/89 366 z PORTLAND MULTNOMAH 97202 4.9 424.80 11/29/88 02/22/89 84 z PORTLAND MULTNOMAH 97202 0.6 231. 10 12/18/88 12/30/89 376 A PORTLAND MULTNOMAH 97202 2.5 937.80 06/10/88 06/09/89 363 A PORTLAND MULTNOMAH 97202 2.2 208.30 02/02/90 05/05/90 92 A PORTLAND MULTNOMAH 97202 6.3 2300.30 11/30/88 11/29/89 363 A PORTLAND MULTNOMAH 97202 6.3 664.20 11/10/89 02/22/90 104 A PORTLAND MULTNOMAH 97202 7 1. 273.70 12/05/88 05/15/89 160 A PORTLAND MULTNOMAH 97202 6.9 2548.80 06/24/88 06/27/89 367 A PORTLAND MULTNOMAH 97202 7.0 634.80 02/17/89 05/18/89 90 A PORTLAND MULTNOMAH 97202 3.0 1099.20 04/10/88 04/10/89 364 A PORTLAND MULTNOMAH 97202 7 1. 656.90 11/27/88 12/02/89 369 z PORTLAND MULTNOMAH 97202 2.3 852.30 04/28/88 05/01/89 367 A PORTLAND MULTNOMAH ~ \.0 t-.) Code Zip Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97202 4.9 540.50 02/25/89 06/14/89 109 A PORTLAND MULTNOMAH 97202 0.8 104.40 12/08/88 04/06/89 118 A PORTLAND MULTNOMAH 97202 1.9 186.90 11/24/89 02/27/90 95 A PORTLAND MULTNOMAH 97202 5.4 2235.80 12/30/88 02/16/90 412 A PORTLAND MULTNOMAH 97203 0.2 77.50 11/03 /88 11/13/89 374 J PORTLAND MULTNOMAH 97203 2 1. 459.10 11/07 /88 11/14/89 371 J PORTLAND MULTNOMAH 97203 0.2 84.20 11/07/88 11/13/89 370 I PORTLAND MULTNOMAH 97203 4.3 1622.70 11/08/88 11/14/89 370 A PORTLAND MULTNOMAH 97203 1 1. 442.20 11/08/88 11/13/89 369 I PORTLAND MULTNOMAH 97203 0.2 92.70 11/03/88 11/13 /89 374 J PORTLAND MULTNOMAH 97203 0.1 67.30 11/09/88 11/13/89 368 J PORTLAND MULTNOMAH 97203 4.2 1572 .10 11/09/88 11/14/89 369 I PORTLAND MULTNOMAH 97203 0.3 129.80 11/03/88 11/13/89 374 J PORTLAND MULTNOMAH 97203 3.4 1283.30 11/02/88 11/14/89 376 J PORTLAND MULTNOMAH 97203 3.3 1247.90 11/02/88 11/14/89 376 J PORTLAND MULTNOMAH 97203 2.6 244.20 03/01/89 05/31/89 91 A PORTLAND MULTNOMAH 97203 5.3 2004.50 11/04/88 11/14/89 374 I PORTLAND MULTNOMAH 97203 0.5 214.30 11/03/88 11/13/89 374 J PORTLAND MULTlJOMAH 97203 1. 0 403.40 11/07/88 11/14/89 371 A PORTLAND MULTNOMAH 97203 5.3 1986.40 11/08/88 11/14/89 370 I PORTLAND MULTNOMAH 97203 2.3 871.20 11/04/88 11/14/89 374 I PORTLAND MULTNOMAH 97203 0.6 236.20 11/07/88 11/14/89 371 I PORTLAND MULTNOMAH 97203 7.2 481.10 11/08/88 01/13/89 65 J PORTLAND MULTNOMAH 97203 0.1 55.50 11/04/88 11/13/89 373 J PORTLAND MULTNOMAH 97203 2.2 825.60 11/03/88 11/13/89 374 A PORTLAND MULTNOMAH 97203 4.1 275.10 11/07/88 01/13/89 66 J PORTLAND MULTNOMAH 97203 9 1. 700.20 03/24/89 03/22/90 363 E PORTLAND MULTNOMAH 97203 9.4 3568.10 11/02/88 11/13/89 375 J PORTLAND MULTNOMAH J-l \.() w Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97203 1. 9 707.20 03/25/89 03/23/90 363 B PORTLAND MULTNOMAH 97203 0.7 284.00 07/09/88 07 /11/89 366 A PORTLAND MULTNOMAH 97203 1.9 717.50 11/04/88 11/14/89 374 A PORTLAND MULTNOMAH 97203 7 1. 631. 90 11/0B/88 11/14/89 370 I PORTLAND MULTNOMAH 97203 0.6 258.20 11/07 /88 11/14/89 371 J PORTLAND MULTNOMAH 97203 1.5 579.00 11/07 /88 11/13/89 370 I PORTLAND MULTNOMAH 97203 9.6 683.70 11/04/88 01/14/89 70 I PORTLAND MULTNOMAH 97203 0.7 291.90 11/02/88 11/14/89 376 J PORTLAND MULTNOMAH 97203 0.7 247.10 12/14/88 11/25/89 345 B PORTLAND MULTNOMAH 97203 3 1. 487.80 11/03 /88 11/13/89 374 J PORTLAND MULTNOMAH 97203 8.2 543.60 11/08/88 01/13/89 65 I PORTLAND MULTNOMAH 97203 0.7 83.90 12/04/88 03/24/89 109 F PORTLAND MULTNOMAH 97203 O.B 329.10 11/02/88 11/14/89 376 A PORTLAND MULTNOMAH 97203 1. 3 508.10 11/03/88 11/14/89 375 J PORTLAND MULTNOMAH 97203 0.9 342.60 11/03/88 11/14/89 375 J PORTLAND MULTNOMAH 97203 0.8 302.10 11/09/88 11/13/89 368 I PORTLAND MULTNOMAH 97203 0.8 305.50 11/07/88 11/13/89 370 J PORTLAND MULTNOMAH 97203 1.5 563.80 11/08/88 11/14/89 370 I PORTLAND MULTNOMAH 97203 9.2 3625.50 01/13/89 02/07/90 390 z PORTLAND MULTNOMAH 97203 0.9 346.00 11/02/88 11/14/89 376 J PORTLAND MULTNOMAH 97203 3.5 1278.50 06/17/88 06/09/89 356 A PORTLAND MULTNOMAH 97203 1. 0 389.90 11/02/88 11/14/89 376 J PORTLAND MULTtlOMAH 97203 0.1 67.30 11/03/88 11/13/89 374 J PORTLAND MULTNOMAH 97203 3.7 1404.90 11/03/88 11/14/89 375 PORTLAND MULTNOMAH 97203 1.1 433.80 11/04/88 11/14/89 374 I PORTLAND MULTNOMAH 97203 3.6 1361. 00 11/03/88 11/13/89 374 A PORTLAND MULTNOMAH 97203 9.5 3728.10 01/13 /89 02/07/90 390 z PORTLAND MULTNOMAH 97203 2.3 856.70 03/13/89 03/17/90 369 A PORTLAND MULTNOMAH 1-1 \D tf::i. Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97206 0.9 335.50 09/23/89 09/21/90 363 A PORTLAND MULTNOMAH 97206 1.2 187.60 02/11/89 07/12/89 151 A PORTLAND MULTNOMAH 97206 2.2 201.80 01/05/90 04/03/90 88 B PORTLAND MULTNOMAH 97206 3.1 1154.10 02/27/89 03/05/90 371 PORTLAND MULTNOMAH 97206 1.3 490.10 05/07/88 05/10/89 367 J PORTLAND MULTNOMAH 97206 2.2 203.60 02/18/89 05/18/89 89 B PORTLAND MULTNOMAH 97206 2.3 221.10 01/01/90 04/06/90 95 A PORTLAND MULTNOMAH 97206 2.4 12.60 02/24/90 03/01/90 5 A PORTLAND MULTNOMAH 97206 3.4 1292.00 10/26/88 11/02/89 371 c PORTLAND MULTNOMAH 97206 3.6 1374.80 10/26/88 11/02/89 371 E PORTLAND MULTNOMAH 97206 8 13. 4804.60 06/30/88 06/12/89 346 A PORTLAND MULTNOMAH 97206 4.7 1779.00 10/26/88 11/02/89 371 A PORTLAND MULTNOMAH 97206 4.6 1598.90 06/30/88 06/12/89 346 E PORTLAND MULTNOMAH 97210 5.7 28.60 05/03/89 05/08/89 5 A PORTLAND MULTlWMAH 97210 8 1. 175.90 12/24/89 03/27/90 93 A PORTLAND MULTNOMAH 97210 1.4 130. 60 04/24/89 07/24/89 91 A PORTLAND MULTNOMAH 97210 1. 9 737.80 12/09/88 12/27/89 382 A PORTLAND MULTNOMAH 97210 0.9 89.80 03/28/89 06/28/89 92 D PORTLAND MULTNOMAH 97210 5.0 401.10 10/25/88 01/12/89 78 A PORTLAND MULTNOMAH 97210 3.6 334.30 12/09/89 03/10/90 91 A PORTLAND MULTNOMAH 97210 1. 3 126.00 03/28/89 06/28/89 92 A PORTLAND MULTNOMAH 97210 0.6 260.90 04/21/89 05/12/90 386 A PORTLAND MULTNOMAH 97210 0.7 72 .10 03/28/89 06/28/89 92 E PORTLAND MULTNOMAH 97210 0.7 65.40 03/28/89 06/28/89 92 G PORTLAND MULTNOMAH 97210 0.7 284.00 07/17/88 08/21/89 399 z PORTLAND MULTNOMAH 97210 0.9 364.60 01/18/89 02/01/90 379 A PORTLAND MULTNOMAH 97210 2.2 752 .10 10/08/88 09/11/89 337 A PORTLAND MULTNOMAH 97210 2.0 173.90 08/21/89 11/13/89 84 A PORTLAND MULTNOMAH r-i \.D U1 Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97210 3.5 308.50 12/17/89 03/14/90 87 A PORTLAND MULTNOMAH 97210 2.1 462.30 03 /13 /89 10/18/89 219 A PORTLAND MULTNOMAH 97210 1. 7 163.90 03/28/89 06/28/89 92 A PORTLAND MULTNOMAH 97210 1.1 430.00 12/09/88 12/27/89 382 A PORTLAND MULTNOMAH 97210 1. 3 119. 80 03/07/90 06/07/90 92 A PORTLAND MULTNOMAH 97210 2.1 207.00 05/14/89 08/17/89 95 z PORTLAND MULTNOMAH 97210 1. 7 10.20 05/15/89 05/21/89 6 A PORTLAND MULTNOMAH 97210 2.6 232.00 01/12/90 04/10/90 88 I PORTLAND MULTNOMAH 97210 0.6 224.30 12/01/88 12/03/89 366 A PORTLAND MULTNOMAH 97210 0.9 344.10 05/03/88 05/06/89 367 B PORTLAND MULTNOMAH 97210 1.3 124.10 01/31/90 04/30/90 89 A PORTLAND MULTNOMAH 97210 0.4 157.90 12/28/88 12/28/89 364 J PORTLAND MULTNOMAH 97210 0.6 55.70 03/28/89 06/28/89 92 B PORTLAND MULTNOMAH 97210 0.6 63.70 03/28/89 06/28/89 92 F PORTLAND MULTNOMAH 97210 0.4 175.70 12/02/88 12/05/89 367 A PORTLAND MULTNOMAH 97210 2.8 266.90 04/09/89 07/12/89 94 A PORTLAND MULTNOMAH 97211 2.8 1026.70 04/28/88 04/28/89 364 A PORTLAND MULTNOMAH 97211 2.3 328.50 12/07/89 04/28/90 142 A PORTLAND MULTNOMAH 97211 8.2 774.90 12/31/89 04/04/90 94 A PORTLAND MULTNOMAH 97211 4.7 1733.00 03/13/89 03/13/90 365 A PORTLAND MULTNOMAH 97211 7.0 2581. 40 07/30/89 07/30/90 365 E PORTLAND MULTNOMAH 97211 5.0 669.80 11/26/89 04/08/90 133 A PORTLAND MULTNOMAH 97211 3.3 1222.30 04/09/88 04/10/89 365 B PORTLAND MULTNOMAH 97211 3.0 283.10 12/16/89 03/18/90 92 z PORTLAND MULTNOMAH 97211 4.3 2253.50 04/20/89 09/18/90 516 A PORTLAND MULTNOMAH 97211 3.2 290.50 12/24/89 03/23/90 89 A PORTLAND MULTNOMAH 97211 1. 6 144. 00 02/15/90 05/16/90 90 A PORTLAND MULTNOMAH 97211 3.8 419.20 12/16/89 04/04/90 109 A PORTLAND MULTNOMAH ~ \.0 O'\ Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97211 3.7 348.90 12/10/88 03/12/89 91 A PORTLAND MULTNOMAH 97211 4.1 44 7. 60 01/21/90 05/09/90 108 A PORTLAND MULTNOMAH 97211 3.0 1491.70 05/01/88 09/05/89 491 A PORTLAND MULTNOMAH 97211 4.4 1680.40 04/17/88 04/26/89 373 A PORTLAND MULTNOMAH 97211 3.1 298.30 01/01/90 04/07/90 96 A PORTLAND MULTNOMAH 97211 12.8 5327.60 04/11/88 05/30/89 413 A PORTLAND MULTNOMAH 97211 2.0 381.60 12/21/89 06/28/90 189 A PORTLAND MULTNOMAH 97211 10.3 165.50 01/12/90 01/28/90 16 A PORTLAND MULTNOMAH 97211 2.5 233.40 01/21/90 04/23/90 92 A PORTLAND MULTNOMAH 97211 5.2 517.30 01/21/90 04/29/90 98 B PORTLAND MULTNOMAH 97211 1. 8 755.80 04/18/88 05/25/89 401 E PORTLAND MULTNOMAH 97211 8.4 814.90 01/21/90 04/28/90 97 A PORTLAND MULTNOMAH 97211 4.1 419.80 12/16/89 03/26/90 100 A PORTLAND MULTNOMAH 97211 6.4 621.10 12/07/89 03/13/90 96 A PORTLAND MULTNOMAH 97211 1. 5 135.70 03/18/89 06/14/89 88 A PORTLAND MULTNOMAH 97211 6.9 923.90 12/15/89 04/27/90 133 A PORTLAND MULTNOMAH 97211 1. 4 142.20 12/09/89 03/14/90 95 A PORTLAND MULTNOMAH 97211 6.6 627.70 11/23/89 02/25/90 94 A PORTLAND MULTNOMAH 97211 1. 0 422.40 04/21/88 06/01/89 405 E PORTLAND MULTNOMAH 97211 1. 8 231.20 04/28/90 08/29/90 123 A PORTLAND MULTNOMAH 97211 35.5 3303.70 11/26/89 02/27/90 93 A PORTLAND MULTNOMAH 97211 0.4 41. 60 12/15/89 03/19/90 94 A PORTLAND MULTNOMAH 97211 1.4 146.10 12/27/89 04/09/90 103 A PORTLAND MULTNOMAH 97211 0.9 86.30 11/28/89 03/01/90 93 A PORTLAND MULTNOMAH 97211 1. 2 473.40 04/21/89 04/21/90 365 c PORTLAND MULTNOMAH 97211 2.1 717. 40 03/14/89 02/08/90 331 A PORTLAND MULTNOMAH 97211 3.2 3 01. 3 0 06/09/90 09/09/90 92 A PORTLAND MULTNOMAH 97211 8.7 827.50 01/01/90 04/06/90 95 A PORTLAND MULTNOMAH f-l l.D ...J Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97211 4.4 904.80 08/02/89 02/22/90 204 A PORTLAND MULTNOMAH 97212 1. l:i 1362. 50 03/13/89 03/18/90 370 A PORTLAND MULTNOMAH 97212 3.7 1339.70 01/10/89 01/07/90 362 A PORTLAND MULTNOMAH 97212 3.5 1401.70 09/23/88 10/20/89 391 A PORTLAND MULTNOMAH 97212 3.2 1210.70 07/24/89 07/28/90 369 A PORTLAND MULTNOMAH 97212 3.7 342.60 10/29/89 01/28/90 91 A PORTLAND MULTNOMAH 97212 4.7 1915.80 01/29/89 03/11/90 406 A PORTLAND MULTNOMAH 97212 3.0 276.90 01/17/90 04/17/90 90 A PORTLAND MULTNOMAH 97212 4.8 1958.10 01/25/89 03/04/90 403 A PORTLAND MULTNOMAH 97212 4.0 424.60 01/24/89 05/08/89 104 A PORTLAND MULTNOMAH 97212 5.0 50 1861. 04/15/89 04/21/90 371 z PORTLAND MULTNOMAH 97212 2. 8 257.10 01/07/89 04/06/89 89 A PORTLAND MULTNOMAH 97212 5.1 476.80 11/25/89 02/26/90 93 A PORTLAND MULTNOMAH 97212 3.1 502.30 02/07/90 07/14/90 157 z PORTLAND MULTNOMAH 97212 5.4 519.10 12/21/89 03/27/90 96 A PORTLAND MULTNOMAH 97212 7.2 2656.20 06/01/88 06/01/89 364 B PORTLAND MULTNOMAH 97212 1.9 220.70 02/04/89 05/26/89 111 A PORTLAND MULTNOMAH 97212 5.8 2175.10 08/11/88 08/21/89 374 A PORTLAND MULTNOMAH 97212 1. 9 730.90 04/10/88 04/17/89 371 A PORTLAND MULTNOMAH 97212 6.1 2251.70 05/01/88 05/02/89 365 A PORTLAND MULTNOMAH 97212 1. 7 99.10 09/20/89 11/15/89 56 A PORTLAND MULTNOMAH 97212 6.7 2472 .40 12/11/88 12/11/89 364 A PORTLAND MULTNOMAH 97212 1. 6 185.00 12/18/89 04/08/90 111 A PORTLAND MULTNOMAH 97212 1.1 103.10 01/14/90 04/16/90 92 A PORTLAND MULTNOMAH 97212 2.7 166.40 01/26/90 03/27/90 60 A PORTLAND MULTNOMAH 97212 2.7 986.00 12/11/88 12/11/89 364 z PORTLAND MULTNOMAH 97212 2.5 959.90 02/21/89 02/27/90 371 A PORTLAND MULTNOMAH 97212 2.8 1051.00 04/19/88 04/22/89 367 A PORTLAND MULTNOMAH 1--1 ~ CX> Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97212 1. 5 149.00 05/04/89 08/09/89 97 J PORTLAND MULTNOMAH 97212 1. 2 127.80 11/29/89 03/12/90 103 A PORTLAND MULTNOMAH 97212 1.1 107.90 11/29/89 03/06/90 97 A PORTLAND MULTNOMAH 97212 1.1 416.00 03/18/89 03/11/90 358 z PORTLAND MULTNOMAH 97212 0.9 96.00 06/22/90 09/30/90 100 A PORTLAND MULTNOMAH 97212 5.6 2604.50 05/07/89 08/15/90 465 A PORTLAND MULTNOMAH 97212 10.8 1067.60 11/21/89 02/27/90 98 A PORTLAND MULTNOMAH 97212 10.0 1063.40 12/16/89 04/01/90 106 A PORTLAND MULTNOMAH 97212 0.9 363.00 06/06/89 06/19/90 378 A PORTLAND MULTNOMAH 97212 10.3 3788.10 06/01/88 06/01/89 364 A PORTLAND MULTNOMAH 97212 6.8 2965.30 08/22/88 10/29/89 432 A PORTLAND MULTNOMAH 97212 5.2 2081.90 04/22/88 05/22/89 394 A PORTLAND MULTNOMAH 97212 0.1 9.10 01/10/90 04/10/90 90 A PORTLAND MULTNOMAH 97212 15.2 5573.40 06/01/88 06/01/89 364 PORTLAND MULTNOMAH 97212 7.5 2863.90 04/06/88 04/18/89 376 A PORTLAND MULTNOMAH 97212 18.4 1736.00 12/02/89 03/06/90 94 A PORTLAND MULTNOMAH 97212 7.8 3322.50 05/05/88 07/02/89 422 A PORTLAND MULTNOMAH 97212 4.8 450.70 12/26/89 03/29/90 93 I PORTLAND MULTNOMAH 97212 7.7 1286.70 08/14/89 01/27/90 166 A PORTLAND MULTNOMAH 97212 3.2 153.80 03/16/89 05/03/89 48 A PORTLAND MULTNOMAH 97212 8.9 3840.70 07/13/88 09/15/89 428 A PORTLAND MULTNOMAH 97212 4.3 475.60 12/28/89 04/17/90 110 A PORTLAND MULTNOMAH 97212 9.6 3516.50 06/01/88 06/01/89 364 E PORTLAND MULTNOMAH 97212 3.7 407.80 12/31/89 04/18/90 108 A PORTLAND MULTNOMAH 97212 9.3 847.30 01/30/89 05/01/89 91 A PORTLAND MULTNOMAH 97212 3.6 1562.20 07/13/88 09/17/89 430 A PORTLAND MULTNOMAH 97212 4.7 425.70 12/29/89 03/29/90 90 A PORTLAND MULTNOMAH 97212 2.7 251. 70 04/11/90 07/10/90 90 A PORTLAND MULTNOMAH 1-l \.0 \.0 Zip Code Concentration Total Start Date End Date Total Location a City County (pCi /1) Exposure days 97212 3.7 1423.40 11/28/88 12/14/89 380 A PORTLAND MULTNOMAH 97212 3.4 1458. 90 04/07/89 06/06/90 425 A PORTLAND MULTNOMAH 97212 7.6 692. 60 12/18/89 03/19/90 91 A PORTLAND MULTNOMAH 97212 3.1 1165. 00 02/20/89 02/21/90 366 A PORTLAND MULTNOMAH 97212 8.9 3299.40 12/11/88 12/13/89 366 A PORTLAND MULTNOMAH 97212 2.8 285.70 12/01/89 03/10/90 99 A PORTLAND MULTNOMAH 97212 3.5 401.80 02/04/90 05/29/90 114 A PORTLAND MULTNOMAH 97212 5.8 2259.40 03/10/89 04/02/90 388 A PORTLAND MULTNOMAH 97212 9.0 841.20 02/17/90 05/21/90 93 A PORTLAND MULTNOMAH 97212 9.3 3455.60 04/20/88 04/24/89 368 A PORTLAND MULTNOMAH 97212 0.6 54.70 06/18/89 09/06/89 80 B PORTLAND MULTNOMAH 97212 2.1 191.00 01/05/90 04/05/90 90 A PORTLAND MULTNOMAH 97212 2.4 244.70 12/08/89 03/19/90 101 A PORTLAND MULTNOMAH 97212 1. 9 697.40 01/04/89 01/04/90 365 A PORTLAND MULTNOMAH 97212 1. 6 155.20 01/13/90 04/15/90 92 A PORTLAND MULTNOMAH 97212 1.5 187.20 09/04/89 01/06/90 124 c PORTLAND MULTNOMAH 97212 0.5 200.00 06/19/89 06/29/90 375 B PORTLAND MULTNOMAH 97212 1. 6 607.80 12/03/88 12/10/89 371 A PORTLAND MULTNOMAH 97212 2.3 854.60 05/06/89 05/06/90 365 A PORTLAND MULTNOMAH 97212 5.0 456.70 12/24/89 03/24/90 90 A PORTLAND MULTNOMAH 97212 1. 0 378.70 02/20/89 02/21/90 366 E PORTLAND MULTNOMAH 97212 2.6 301.80 01/06/90 04/30/90 114 A PORTLAND MULTNOMAH 97212 3.5 1303.00 11/28/88 11/26/89 362 A PORTLAND MULTNOMAH 97212 6.5 2387.80 01/16/89 01/16/90 365 A PORTLAND MULTNOMAH 97212 1. 7 177.20 05/06/90 08/17/90 103 A PORTLAND MULTNOMAH 97212 0.6 224.80 07/24/89 07/28/90 369 J PORTLAND MULTNOMAH 97212 1.1 122.30 04/21/89 08/08/89 109 c PORTLAND MULTNOMAH 97212 3.8 1447.30 07/29/88 08/06/89 372 A PORTLAND MULTNOMAH f\.) 0 0 Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97212 3.0 277.70 12/08/89 03/10/90 92 A PORTLAND MULTNOMAH 97213 0.5 56.50 01/06/90 04/22/90 106 A PORTLAND MULTNOMAH 97213 0.9 346.90 05/16/88 05/23/89 371 L PORTLAND MULTNOMAH 9721] l. 5 I 185. 60 01/31/90 05/31/90 120 A PORTLAND MULTNOMAH 97213 1.8 629.00 11/15/88 10/30/89 348 A PORTLAND MULTNOMAH 97213 2.4 295.80 01/27/90 05/28/90 121 A PORTLAND MULTNOMAH 97213 2.5 926.90 03/02/89 02/25/90 360 B PORTLAND MULTNOMAH 97213 1.9 186.90 11/24/89 02/27/90 95 A PORTLAND MULTNOMAH 97213 2.3 250.30 11/21/89 MULTNOMAH 03/07/90 106 A PORTLAND 97213 2.3 987.20 11/30/88 01/20/90 415 A PORTLAND MULTNOMAH 97213 1.2 135.10 12/01/89 03/19/90 108 A PORTLAND MULTNOMAH 97213 1.8 181.30 01/15/90 04/24/90 99 A PORTLAND MULTNOMAH 97213 1.7 324.30 12/01/89 06/02/90 183 A PORTLAND MULTNOMAH 97213 1.5 135.10 12/03/89 03/01/90 88 A PORTLAND MULTNOMAH 97213 1. 2 129 .10 11/21/89 03/07/90 106 c PORTLAND MULTNOMAH 97213 0.7 68.70 01/20/90 04/28/90 98 A PORTLAND MULTNOMAH 97213 1.0 114.20 12/04/89 03/19/90 105 B PORTLAND MULTNOMAH 97213 0.8 86.20 11/27/89 03/11/90 104 B PORTLAND MULTNOMAH 97213 2.3 203.40 12/09/89 03/05/90 86 A PORTLAND MULTNOMAH 97213 0.6 52.90 02/08/90 05/03/90 84 A PORTLAND MULTNOMAH 97213 2.0 784.20 05/16/88 05/30/89 378 E PORTLAND MULTNOMAH 97213 2.4 332.00 01/08/90 05/22/90 134 A PORTLAND MULTNOMAH 97213 0. 7 74. 60 05/09/90 08/12/90 95 A PORTLAND MULTNOMAH 97213 5.0 385.10 01/15/89 04/01/89 76 z PORTLAND MULTNOMAH 97213 3 .1 283. 80 12/09/89 03/10/90 91 A PORTLAND MULTNOMAH 97213 8.1 2714.80 06/25/88 05/23/89 331 A PR OT LAND MULTNOMAH 97213 3.2 1202.00 02/28/89 02/28/90 365 A PORTLAND MULTNOMAH 97213 7.2 3032.70 05/03/89 06/28/90 421 A PORTLAND MULTNOM.ru! N 0 ~ Zip Code Concentration Total Date a Start End Date Total Location City County (pCi/l) Exposure days 97213 3. 3 409.60 12/17/89 04/18/90 122 A 97213 PORTLAND MULTNOfwLllJI 6.2 787.10 12/14/89 04/18/90 125 A PORTLAND MULTNOMAH 97213 3. 3 186.50 11/06/89 01/01/90 56 A PORTLAND 97213 7.0 MULTNOMAH 738.10 11/05/89 02/18/90 105 A PORTLAND MULTNOMAH 97213 3. 3 319. 50 04/13/90 07/17/90 95 A PORTLAND 97213 MULTNOMAH 5.8 762.70 11/24/89 04/03/90 130 A PORTLAND MULTNOHAH 97213 3.4 1257.50 03/26/89 03/22/90 361 A PORTLAND 97213 6.0 MULTNOMAH 2631.20 02/14/89 04/25/90 435 A PORTLAND MULTNOMAH 97213 3.7 1402.60 03/26/89 04/03/90 373 A 97213 PORTLAND MULTNOMAH 4.9 613.90 01/08/90 05/12/90 124 z PORTLAND MULTNOMAH 97213 3.9 335.50 02/26/90 05/23/90 86 A PORTLAND 97213 8.1 MULTNOMAH 753.00 08/03/89 11/03/89 92 PORTLAND MULTNOMAH 97213 3.9 343. 80 12/28/89 03/24/90 86 A PORTLAND 97213 7.7 MULTNOMAH 2860.60 02/22/89 02/24/90 367 A PORTLAND MUI,TNOMA!I 97213 4.1 373.60 12/19/89 03/19/90 90 A PORTLAND 97213 1.5 MULTNOMAH 132. 80 04/17/90 07/10/90 84 A PORTLAND MULTNOMAH 97213 4.2 409.20 03/16/90 06/21/90 97 z PORTLAND 97213 5.7 MULTNOMAH 685.80 04/24/90 08/22/90 120 A PORTLAND MULTNOMAH 97213 7.5 731. 10 12/08/89 03/15/90 97 A PORTLAND 97213 6.2 MULTNOMAH 729. 90 02/19/90 06/16/90 117 A PORTLAND MULTNOMAH 97213 5.8 535.20 03/19/90 06/18/90 91 A PORTLAND 97213 MULTNOMAH 4.9 2260.70 04/06/88 07/11/89 460 A PORTLAND MULTNOMAH 97213 4.4 433.00 12/11/89 03/18/90 97 A PORTLAND 97213 4.6 MULTNOMAH 413.20 02/10/90 05/10/90 89 A PORTLAND MULTNOMAH 97213 4.7 481. 80 12/06/89 03/18/90 102 A PORTLAND 97213 MULTNOMAH 4.7 734. 50 11/04/89 04/08/90 155 A PORTLAND MULTNOMAH 97213 2.9 280.60 02/27/89 06/01/89 94 A PORTLAND 97213 MULTNOfwWf 5.7 543.60 12/22/89 03/27/90 95 A PORTLAND MULTNOfwWf t0 0 t0 Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97213 10.3 1194. 80 02/25/90 06/21/90 116 A PORTLAND MULTNOMAH 97213 11.7 1056.20 01/01/90 04/01/90 90 A PORTLAND MULTNOMAH 97213 9.4 1666.30 12/17/89 06/12/90 177 A PORTLAND MULTNOMAH 97213 10.2 1092.30 11/24/89 03/11/90 107 A PORTLAND MULTNOMAH 97213 9.6 3545.90 07/01/88 07/04/89 367 A PORTLAND MULTNOMAH 97213 9.5 867.80 12/16/89 03/17/90 91 A PORTLAND MULTNOMAH 97213 9.1 4089.20 12/18/88 03/09/90 445 A PORTLAND MULTNOMAH 97213 8.3 760.80 12/07/89 03/08/90 91 z PORTLAND MULTNOMAH 97213 10.1 3752.20 01/03/89 01/09/90 371 z PORTLAND MULTNOMAH 97213 13 .1 1223.00 11/25/89 02/26/90 93 A PORTLAND MULTNOMAH 97213 14.6 8097.90 04/18/88 10/21/89 550 A PORTLAND MULTNOMAH 97213 13 .1 4836.90 08/05/88 08/09/89 368 A PORTLAND MULTNOMAH 97213 20.5 2303.30 10/02/89 01/22/90 112 A PORTLAND MULTNOMAH 97213 15.7 1398.10 02/15/89 05/15/89 89 A PORTLAND MULTNOMAH 97213 5.7 849.70 12/17/89 05/13/90 147 A PORTLAND MULTNOMAH 97213 3.0 415.10 12/29/89 05/13/90 135 A PORTLAND MULTNOMAH 97214 0.9 377.20 02/12/89 03/27/90 408 A PORTLAND MULTNOMAH 97214 6.3 519.90 11/20/89 02/10/90 82 A PORTLAND MULTNOMAH 97214 0.2 76.60 12/17/88 12/17/89 364 A PORTLAND MULTNOMAH 97214 2.7 1085.10 04/10/88 05/09/89 393 A PORTLAND MULTNOMAH 97214 5.8 93.60 02/21/89 03/09/89 16 A PORTLAND MULTNOMAH 97214 0.8 318.00 05/31/88 05/31/89 364 D PORTLAND MULTNOMAH 97214 0.8 312.70 09/13/89 10/03/90 385 B PORTLAND MULTNOMAH 97214 0.5 197.20 03/22/89 03/22/90 365 A PORTLAND MULTNOMAH 97214 1. 0 391.30 08/30/88 09/09/89 374 B PORTLAND MULTNOMAH 97214 1.1 408.80 10/08/88 10/08/89 364 A PORTLAND MULTNOMAH 97214 1. 7 925.20 04/09/88 09/25/89 533 A PORTLAND MULTNOMAH 97214 1. 8 164.90 11/06/88 02/01/89 86 A PORTLAND MULTNOMAH N 0 w Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97214 1.4 545.00 12/08/88 12/07/89 363 A PORTLAND MULTNOMAH 97214 2.6 975.80 11/25/88 11/25/89 364 A PORTLAND MULTNOMAH 97214 4.5 451.00 04/18/90 07/27/90 100 z PORTLAND MULTNOMAH 97214 1. 8 167.70 05/22/90 08/20/90 90 A PORTLAND MULTNOMAH 97214 2.6 1046.20 04/10/88 05/09/89 393 A PORTLAND MULTNOMAH 97215 2.7 968. 30 10/12/88 10/05/89 357 A PORTLAND MULTNOMAH 97215 2.2 972. 00 03/14/89 05/28/90 440 A PORTLAND MULTNOMAH 97215 2.1 196.50 01/01/90 04/01/90 90 A PORTLAND MULTNOMAH 97215 2.1 819.40 03/17/89 03/27/90 375 A PORTLAND MULTNOMAH 97215 2.5 930.30 10/16/88 10/21/89 369 A PORTLAND MULTNOMAH 97215 2.6 308.60 10/19/89 02/14/90 118 A PORTLAND MULTNOMAH 97215 1. 4 153.40 11/19/89 03/04/90 105 B PORTLAND MULTNOMAH 97215 1.1 413 .20 10/09/89 09/27/90 353 A PORTLAND MULTNOMAH 97215 1.1 420.80 07/10/89 07/10/90 365 A PORTLAND MULTNOMAH 97215 1.5 154.90 02/26/90 06/03/90 97 A PORTLAND MULTNOMAH 97215 1. 4 118. 00 09/22/89 12/15/89 84 z PORTLAND MULTNOMAH 97215 0.8 311.30 11/27 /88 11/29/89 366 E PORTLAND MULTNOMAH 97215 0.8 421.60 04/09/88 07/22/89 468 A PORTLAND MULTNOMAH 97215 0.6 217.30 03/17/89 03/05/90 353 B PORTLAND MULTNOMAH 97215 2.5 870.20 03/30/89 03/05/90 340 A PORTLAND MULTNOMAH 97215 2.6 247.40 12/14/89 03/16/90 92 A PORTLAND MULTNOMAH 97215 2.6 257.40 03/25/89 06/29/89 96 A PORTLAND MULTNOMAH 97215 2.5 203.40 01/15/90 04/06/90 81 A PORTLAND MULTNOMAH 97215 2.7 942.10 03/30/89 03/05/90 340 A PORTLAND MULTNOMAH 97215 3.2 1188. so 04/09/88 04/09/89 364 A PORTLAND MULTNOMAH 97215 3.2 1180. 20 04/27/88 04/26/89 363 A PORTLAND MULTNOMAH 97215 3.2 353.50 03/06/90 06/22/90 108 A PORTLAND MULTNOMAH 97215 3.5 1400.20 11/25/88 12/20/89 389 A PORTLAND MULTNOMAH ~ 0 ~ Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97215 3.7 1372.90 04/29/89 04/29/90 365 I PORTLAND MULTNOMAH 97215 1.0 105.90 12/15/89 03/27/90 102 A PORTLAND MULTNOMAH 97215 l. 0 127.30 01/06/90 05/06/90 120 A PORTLAND MULTNOMAH 97215 0.5 196.60 10/15/88 10/21/89 370 B PORTLAND MULTNOMAH 97216 1.3 611. 60 04/18/88 07/23/89 460 E PORTLAND MULTNOMAH 97216 0.9 140.00 04/17/90 09/10/90 146 A PORTLAND MULTNOMAH 97216 l. 5 581.80 04/09/88 04/08/89 363 B PORTLAND MULTNOMAH 97216 1.4 525.60 12/16/88 12/20/89 368 D PORTLAND MULTNOMAH 97216 2.4 845.90 03/17/89 03/04/90 352 c PORTLAND MULTNOMAH 97216 l. 6 687.00 09/28/88 11/21/89 418 A PORTLAND MULTNOMAH 97216 l. 7 158.40 02/22/89 05/22/89 89 z PORTLAND MULTNOMAH 97216 l. 3 118. 90 03/09/90 06/04/90 87 A PORTLAND MULTNOMAH 97216 2.6 951.60 12/05/88 12/06/89 365 A PORTLAND MULTNOMAH 97216 2.6 239.80 12/06/89 03/06/90 90 A PORTLAND MULTNOMAH 97217 6.9 2613.00 10/03/88 10/16/89 377 A PORTLAND MULTNOMAH 97217 10.2 3494.40 11/09/88 10/16/89 340 A PORTLAND MULTNOMAH 97217 2.0 738.80 05/02/89 05/03/90 366 A PORTLAND MULTNOMAH 97217 9.3 953.20 11/27/89 03/09/90 102 A PORTLAND MULTNOMAH 97217 6.5 2641.60 03/05/89 04/10/90 401 A PORTLAND MULTNOMAH 97217 0.7 65.10 03/02/90 06/02/90 92 A PORTLAND MULTNOMAH 97217 2.0 188.90 05/02/89 08/03/89 93 B PORTLAND MULTNOMAH 97217 4.9 454.30 11/12/89 02/12/90 92 A PORTLAND MULTNOMAH 97217 0.7 283.10 03/24/89 04/04/90 376 A PORTLAND MULTNOMAH 97217 4.9 448.00 02/07/90 05/09/90 91 A PORTLAND MULTNOMAH 97217 5.9 554.30 05/02/89 08/03/89 93 A PORTLAND MULTNOMAH 97217 3. 8 1463.60 03/18/89 04/01/90 379 B PORTLAND MULTNOMAH 97217 3.3 1197. 90 03/21/89 03/12/90 356 A PORTLAND MULTNOMAH 97217 4.8 417.70 04/22/90 07/17/90 86 A PORTLAND MULTNOMAH ~ 0 Ul Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97217 2.6 254.80 10/21/89 01/24/90 95 B PORTLAND MULTNOMAH 97217 2.7 267.40 02/02/90 05/09/90 96 A PORTLAND MULTNOMAH 97217 1.1 486.90 06/01/88 08/01/89 425 z PORTLAND MULTNOMAH 97218 2.6 238.70 01/11/90 04/12/90 91 A PORTLAND MULTNOMAH 97218 7.0 658.30 11/27/89 02/28/90 93 A PORTLAND MULTNOMAH 97218 5.8 746.80 11/26/88 04/03/89 127 A PORTLAND MULTNOMAH 97218 4.5 408.70 12/10/89 03/10/90 90 A PORTLAND MULTNOMAH 97218 11. 3 1025.50 02/21/90 05/22/90 90 A PORTLAND MULTNOMAH 97218 3.8 1499.30 04/16/88 05/09/89 387 A PORTLAND MULTNOMAH 97218 1.1 91.70 12/18/89 03/06/90 78 z PORTLAND MULTNOMAH 97218 0.4 47.00 04/17/90 08/02/90 107 J PORTLAND MULTNOMAH 97218 4.1 280.70 12/28/89 03/05/90 67 E PORTLAND MULTNOMAH 97218 3.3 301.20 12/09/89 03/09/90 90 c PORTLAND MULTNOMAH 97218 2.8 261.40 11/24/89 02/24/90 92 A PORTLAND MULTNOMAH 97218 14.3 5237.40 07/03/89 07/03/90 365 A PORTLAND MULTNOMAH 97218 3.6 368.00 12/17/88 03/29/89 101 A PORTLAND MULTNOMAH 97218 6.8 611.80 12/06/89 03/05/90 89 J PORTLAND MULTNOMAH 97218 2.5 258.20 07/21/89 10/30/89 101 A PORTLAND MULTNOMAH 97218 0.2 48.20 11/23/89 07/12/90 231 E PORTLAND MULTNOMAH 97218 10.9 951.90 01/08/89 04/05/89 87 A PORTLAND MULTNOMAH 97218 5.1 774.30 01/10/90 06/10/90 151 A PORTLAND MULTNOMAH 97218 6.3 426.20 01/08/90 03/16/90 67 A PORTLAND MULTNOMAH 97218 6.6 673.20 12/03/89 03/14/90 101 A PORTLAND MULTNOMAH 97218 1. 5 162.70 12/12/89 03/24/90 102 A PORTLAND MULTNOMAH 97218 1. 3 102.50 12/18/89 03/06/90 78 z PORTLAND MULTNOMAH 97218 2.8 173.80 03/07/90 05/06/90 60 A PORTLAND MULTNOMAH 97219 4.3 258.80 01/03/90 03/03/90 59 A PORTLAND MULTNOMAH 97219 1. 0 434.00 04/12/88 06/19/89 432 PORTLAND MULTNOMAH N 0 °' Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97219 0.9 300.30 11/05/88 09/21/89 319 J PORTLAND MULTNOMAH 97219 1.1 434.10 02/27/89 02/28/90 366 A PORTLAND MULTNOMAH 97219 1.1 373.50 10/05/88 08/29/89 327 z PORTLAND MULTNOMAH 97219 0.9 341.30 09/01/88 09/01/89 364 E PORTLAND MULTNOMAH 97219 1. 0 414.20 03/10/89 04/21/90 407 c PORTLAND MULTNOMAH 97219 1. 5 141.90 03/02/90 06/01/90 91 A PORTLAND MULTNOMAH 97219 6.1 2313.30 09/01/88 09/13/89 376 A PORTLAND MULTNOMAH 97219 1. 3 119. 60 04/01/89 07/01/89 91 A PORTLAND MULTNOMAH 97219 0.9 85.20 02/11/90 05/09/90 87 D PORTLAND MULTNOMAH 97219 1. 6 107.70 10/21/89 12/27/89 67 B PORTLAND MULTNOMAH 97219 0.9 81.60 03/30/90 06/25/90 87 E PORTLAND MULTNOMAH 97219 2.3 222.70 09/19/89 12/24/89 96 A PORTLAND MULTNOMAH 97219 0.9 360.00 04/02/89 04/21/90 384 E PORTLAND MULTNOMAH 97219 2.7 401.10 12/23/89 05/17/90 145 A PORTLAND MULTNOMAH 97219 0.8 493.00 04/21/88 11/09/89 566 A PORTLAND MULTNOMAH 97219 4.0 1671.10 03/06/89 04/21/90 411 A PORTLAND MULTNOMAH 97219 3.2 1256.30 04/11/88 05/01/89 384 E PORTLAND MULTNOMAH 97219 0.8 77.00 12/04/89 03/04/90 90 A PORTLAND MULTNOMAH 97219 1. 4 174.90 12/13/88 04/13/89 120 B PORTLAND MULTNOMAH 97219 1. 2 146.80 12/25/89 04/26/90 122 A PORTLAND MULTNOMAH 97219 0.9 386.30 04/10/88 05/16/89 400 D PORTLAND MULTNOMAH 97219 5.2 2212.80 12/03/88 01/25/90 417 A PORTLAND MULTNOMAH 97219 0.5 108.80 11/08/89 05/16/90 189 A PORTLAND MULTNOMAH 97219 0.7 299.90 02/22/89 04/06/90 408 PORTLAND MULTNOMAH 97219 0.5 59.70 05/03/90 08/12/90 101 A PORTLAND MULTNOMAH 97219 0.7 147.80 03/06/90 09/12/90 190 A PORTLAND MULTNOMAH 97219 0.6 226.50 05/28/88 06/08/89 375 A PORTLAND MULTNOMAH 97219 0.7 295.10 04/24/88 05/07/89 377 A PORTLAND MULTNOMAH f\.) 0 -...J Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97219 0.7 306.30 12/08/88 12/29/89 385 A PORTLAND MULTNOMAH 97219 0.6 57.60 04/01/89 07/01/89 91 B PORTLAND MULTNOMAH 97219 0.6 248.70 05/28/88 06/08/89 375 A PORTLAND MULTNOMAH 97219 0.4 38.20 01/31/90 04/28/90 87 B PORTLAND MULTNOMAH 97219 0.4 40.00 02/15/90 05/15/90 89 A PORTLAND MULTNOMAH 97219 0.5 192.80 12/11/88 12/29/89 382 A PORTLAND MULTNOMAH 97219 0.4 146.70 04/08/88 04/06/89 362 c PORTLAND MULTNOMAH 97219 1. 6 146.70 02/01/90 05/01/90 89 A PORTLAND MULTNOMAH 97219 3.2 295.30 08/30/89 11/3 0/89 92 A PORTLAND MULTNOMAH 97219 0.4 160.00 04/24/88 05/05/89 375 c PORTLAND MULTNOMAH 97219 0.4 141. 2 0 02/27/89 02/12/90 350 B PORTLAND MULTNOMAH 97219 0.3 136. 00 02/19/89 03/08/90 382 B PORTLAND MULTNOMAH 97219 0.3 145.70 05/28/88 06/08/89 375 B PORTLAND MULTNOMAH 97219 0.3 33.60 02/17/90 05/17/90 89 E PORTLAND MULTNOMAH 97219 0.2 109.20 05/28/88 06/08/89 375 E PORTLAND MULTNOMAH 97219 0.2 74.90 02/23/89 02/10/90 352 c PORTLAND MULTNOMAH 97219 1. 3 528.60 05/27/89 06/17/90 386 z PORTLAND MULTNOMAH 97219 0.1 55.90 12/17/88 12/30/89 377 E PORTLAND MULTNOMAH 97219 2.5 388.00 05/20/89 10/22/89 155 A PORTLAND MULTNOMAH 97220 2.4 256.00 11/28/89 03/12/90 104 A PORTLAND MULTNOMAH 97220 0.7 5.50 02/15/89 02/22/89 7 A PORTLAND MULTNOMAH 97220 0.8 79.00 12/05/89 03/05/90 90 A PORTLAND MULTNOMAH 97220 0.8 98.90 01/08/90 05/09/90 121 A PORTLAND MULTNOMAH 97220 2. 0 235.40 12/10/89 04/04/90 115 A PORTLAND MULTNOMAH 97220 2.7 1208.20 04/15/88 06/28/89 438 A PORTLAND MULTNOMAH 97220 1.1 527.90 04/09/88 06/27/89 443 E PORTLAND MULTNOMAH 97220 2.0 835.20 03/01/89 04/09/90 404 B PORTLAND MULTNOMAH 97220 2.3 856.20 04/01/89 04/05/90 369 B PORTLAND MULTNOMAH N 0 00 Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97220 2.5 234.20 07/13/90 10/13/90 92 A PORTLAND MULTNOMAH 97220 2.8 342.70 11/20/89 03/19/90 119 B PORTLAND MULTNOMAH 97220 3.5 1339. 60 05/03/88 05/17/89 378 A PORTLAND MULTNOMAH 97220 2.0 681.90 04/13/88 03/19/89 339 J PORTLAND MULTNOMAH 97220 3.0 1156. 50 04/12/88 04/21/89 373 A PORTLAND MULTNOMAH 97220 0.7 134.30 01/20/90 07/07/90 168 A PORTLAND MULTNOMAH 97220 13 .1 1198. 90 02/18/90 05/20/90 91 A PORTLAND MULTNOMAH 97220 6.6 586.30 02/27/89 05/26/89 88 A PORTLAND MULTNOMAH 97220 4.4 1602.70 04/07/88 04/04/89 361 F PORTLAND MULTNOMAH 97220 25.0 8737.90 04/17/88 04/01/89 348 A PORTLAND MULTNOMAH 97220 3.8 362.10 11/27/89 03/01/90 94 A PORTLAND MULTNOMAH 97220 4.6 1683.40 03/09/89 03/08/90 364 A PORTLAND MULTNOMAH 97220 10.3 883.60 02/26/89 05/22/89 85 A PORTLAND MULTNOMAH 97220 4.4 263.20 01/10/90 03/10/90 59 A PORTLAND MULTNOMAH 97220 6.8 473.90 01/09/90 03/19/90 69 A PORTLAND MULTNOMAH 97220 3.8 342.70 12/11/89 03/11/90 90 A PORTLAND MULTNOMAH 97220 3.1 283.80 12/11/89 03/12/90 91 D PORTLAND MULTNOMAH 97220 14.0 1445.20 12/12/88 03/25/89 102 A PORTLAND MULTNOMAH 97220 9.9 3714.90 04/25/88 05/05/89 374 A PORTLAND MULTNOMAH 97220 7.6 727.30 12/08/89 03/13/90 95 c PORTLAND MULTNOMAH 97220 33.9 3127.40 01/14/90 04/16/90 92 A PORTLAND MULTNOMAH 97220 5.5 2034.10 05/22/89 05/22/90 365 I PORTLAND MULTNOMAH 97220 13. 8 1705.60 02/11/90 06/14/90 123 A PORTLAND MULTNOMAH 97220 11. 6 1050.10 01/20/90 04/20/90 90 A PORTLAND MULTNOMAH 97221 0.8 69.40 03/11/89 06/03/89 84 E PORTLAND MULTNOMAH 97221 1.1 3 71. 60 11/26/88 10/25/89 332 J PORTLAND MULTNOMAH 97221 0.8 266.10 10/01/88 08/25/89 327 A PORTLAND MULTNOMAH 97221 0.8 82.70 01/05/90 04/09/90 94 A PORTLAND MULTNOMAH N 0 l..O Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97221 0.4 67.60 04/27/90 09/13/90 139 A PORTLAND MULTNOMAH 97221 1. 3 485.80 07/24/88 07/23/89 363 z PORTLAND MULTNOMAH 97221 0.6 301.20 05/09/88 08/31/89 478 A PORTLAND MULTNOMAH 97221 1. 4 177.90 10/17/88 02/18/89 123 A PORTLAND MULTNOMAH 97221 1.3 556.80 04/16/88 05/27/89 405 A PORTLAND MULTNOMAH 97221 0.8 324.30 03/04/89 03/01/90 362 B PORTLAND MULTNOMAH 97221 0.5 185.00 07/10/88 07/10/89 364 c PORTLAND MULTNOMAH 97221 1.1 446.40 12/12/88 12/20/89 372 B PORTLAND MULTNOMAH 97221 0.2 102.60 07/03/88 07/08/89 369 B PORTLAND MULTNOMAH 97221 0.6 229.50 11/27/88 11/27/89 364 c PORTLAND MULTNOMAH 97221 0.3 2.40 04/27/90 05/04/90 7 A PORTLAND MULTNOMAH 97221 1.1 402.50 12/26/88 12/25/89 363 A PORTLAND MULTNOMAH 97221 4.8 301.20 07/25/89 09/25/89 62 I PORTLAND MULTNOMAH 97221 2.8 519.60 02/26/89 08/26/89 181 A PORTLAND MULTNOMAH 97221 3.4 337.40 11/20/88 02/25/89 96 A PORTLAND MULTNOMAH 97221 4.2 386.40 03/14/89 06/13/89 91 A PORTLAND MULTNOMAH 97221 2.8 236.50 11/20/88 02/11/89 82 I PORTLAND MULTNOMAH 97221 1. 7 622.50 03/23/88 03/12/89 353 c PORTLAND MULTNOMAH 97221 0.2 78.30 06/10/88 05/25/89 348 z PORTLAND MULTNOMAH 97221 2.5 495.00 12/06/88 06/21/89 196 z PORTLAND MULTNOMAH 97221 1.6 588.80 03/23/88 03/12/89 353 I PORTLAND MULTNOMAH 97221 2.6 361.90 05/23/90 10/08/90 138 A PORTLAND MULTNOMAH 97221 1. 2 112. so 01/11/90 04/11/90 90 A PORTLAND MULTNOMAH 97221 0.3 126.00 01/08/89 01/14/90 371 A PORTLAND MULTNOMAH 97221 1. 6 305.20 01/18/90 07/22/90 185 c PORTLAND MULTNOMAH 97221 1. 5 150.80 12/04/88 03/13/89 98 A PORTLAND MULTNOMAH 97221 1. 7 619.20 03/23/88 03/12/89 353 A PORTLAND MULTNOMAH 97221 7.0 5134.30 09/17/88 09/16/90 728 A PORTLAND MULTNOMAH N 1-l 0 Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97221 1.5 133 .10 02/16/89 05/14/89 87 B PORTLAND MULTNOMAH 97221 1. 6 617.90 12/10/88 12/10/89 364 I PORTLAND MULTNOMAH 97221 1.5 702.90 03/01/89 06/08/90 464 A PORTLAND MULTNOMAH 97221 1. 4 767.70 11/25/88 05/12/90 532 A PORTLAND MULTNOMAH 97221 1. 4 533.70 12/26/88 12/24/89 362 A PORTLAND MULTNOMAH 97222 7.2 1378.30 02/27/89 09/06/89 191 z PORTLAND CLACKAMAS 97222 1.1 103.40 05/24/90 08/24/90 92 A MILWAUKIE CLACKAMAS 97222 1.6 639.10 05/03/88 05/26/89 387 A MILWAUKIE CLACKAMAS 97222 3.1 568.50 01/19/90 07/20/90 182 A MILWAUKIE CLACKAMAS 97222 4.8 413.50 01/21/89 04/17/89 86 A MILWAUKIE CLACKAMAS 97222 4.2 1518.90 05/18/88 05/09/89 355 z MILWAUKIE CLACKAMAS 97222 1.3 80.60 01/02/89 03/05/89 62 E MILWAUKEE CLACKAMAS 97222 1.6 596.80 02/28/89 03/01/90 366 c MILWAUKIE CLACKAMAS 97222 0.6 219.50 12/02/88 12/02/89 364 E MILWAUKIE CLACKAMAS 97222 3.6 334.10 01/10/90 04/11/90 91 B MILWAUKIE CLACKAMAS 97222 1.5 431.40 01/15/89 10/18/89 276 A MILWAUKIE CLACKAMAS 97222 0.7 69.30 03/01/89 05/30/89 90 B MILWAUKIE CLACKAMAS 97222 3.2 1188. 10 11/27 /88 11/24/89 361 A PORTLAND CLACKAMAS 97222 0.2 89.10 02/27/89 03/10/90 376 B MILWAUKIE CLACKAMAS 97222 0.4 105.40 10/30/88 05/30/89 211 B MILWAUKIE CLACKAMAS 97222 0.5 323.80 03/26/89 10/02/90 555 A PORTLAND CLACKAMAS 97223 2.3 985.70 04/26/88 06/23/89 422 A TIGARD WASHINGTON 97223 2.3 845.00 04/06/88 03/30/89 357 A PORTLAND WASHINGTON 97223 1.1 451.50 05/06/88 06/16/89 405 A TIGARD WASHINGTON 97223 0.5 79.00 12/23/89 05/19/90 147 A TIGARD WASHINGTON 97223 0.5 203.60 05/28/89 05/27/90 364 B TOGARD WASHINGTON 97223 2.8 292.50 01/11/89 04/25/89 104 A PORTLAND WASHINGTON 97223 0.2 107.90 12/05/88 12/05/89 364 B PORTLAND WASHINGTON I\) ~ ~ Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97223 2.9 1233.60 04/18/88 06/06/89 413 A PORTLAND WASHINGTON 97223 0.3 32.90 01/02/89 04/06/89 94 G PORTLAND WASHINGTON 97223 2.9 274.50 11/26/89 02/28/90 94 c PORTLAND WASHINGTON 97223 2.0 578.50 04/10/89 01/20/90 285 I TIGARD WASHINGTON 97223 2.1 192.50 01/21/90 04/21/90 90 c PORTLAND WASHINGTON 97223 0.5 54.40 01/22/90 04/23/90 91 F TIDARD WASHINGTON 97223 1.0 384.30 05/14/89 05/15/90 366 B PORTLAND WASHINGTON 97223 0.8 74.10 11/17/89 02/09/90 84 c PORTLAND WASHINGTON 97223 1.6 136.30 04/09/90 07/03/90 85 E PORTLAND WASHINGTON 97223 1.1 470.70 04/18/88 06/06/89 413 D PORTLAND WASHINGTON 97223 1.6 119.00 01/06/90 03/21/90 74 c TIGARD WASHINGTON 97223 1.6 153.10 03/10/89 95 A TIGARD WASHINGTON 06/13/89 97223 1.4 540.00 04/17/88 364 B TIGARD WASHINGTON 97223 1.5 149.80 11/05/89 04/17/89 98 A TIGARD WASHINGTON 97223 1.1 446.70 05/16/88 02/11/90 377 E TIGARD WASHINGTON 97223 1.3 123.60 WASHINGTON 01/10/90 04/15/9005/29/89 95 B TIGARD 97223 1.3 499.90 05/01/88 05/20/89 383 J TIGARD WASHINGTON WASHINGTON 97223 1.3 762.20 04/09/88 10/25/89 563 c PORTLAND 97223 2.8 268.10 10/26/89 01/27/90 93 B TIGARD WASHINGTON 97223 0.5 79.70 04/15/89 09/07/89 145 A TIGARD WASHINGTON 97223 0.5 200.60 11/26/88 11/30/89 368 B PORTLAND WASHINGTON 97223 0.3 113.10 03/02/89 03/02/90 365 B PORTLAND WASHINGTON 97223 0.4 186.70 02/28/89 04/09/90 405 c PORTLAND WASHINGTON 97223 0.5 217.70 04/28/88 04/30/89 366 c TIGARD WASHINGTON 97223 1.6 599.80 05/31/88 05/31/89 364 c TIGARD WASHINGTON 97223 8.3 2432.50 03/25/89 290 A PORTLAND WASHINGTON 01/09/90 97223 3.0 1154.80 04/11/88 04/27/89 380 A PORTLAND WASHINGTON 97223 4.4 400.40 01/05/89 04/05/89 90 A PORTLAND WASHINGTON N j-J N Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97223 3.2 298.50 07/01/90 10/02/90 93 I TIGARD WASHINGTON 97224 1. 4 538.30 05/05/88 05/07/89 366 J KING CITY WASHINGTON 97224 1. 3 132.90 01/24/90 05/01/90 97 c TIGARD WASHINGTON 97224 1.3 486.50 05/02/89 05/02/90 365 B TIGARD WASHINGTON 1.2 468.60 97224 06/26/89 07/04/90 373 E PORTLAND WASHINGTON 97224 1. 7 660.10 04/09/88 04/29/89 384 A TIGARD WASHINGTON 97224 2.1 795.80 10/22/88 10/31/89 373 J TIGARD WASHINGTON 97224 1.6 150.80 03/25/89 06/27/89 94 c TIGARD WASHINGTON 97224 2.4 916.70 08/25/88 08/30/89 369 A TIGARD WASHINGTON 97224 3.0 263.70 05/03/89 07/29/89 87 A PORTLAND WASHINGTON 97224 2.3 870.00 05/07/88 05/13/89 370 A TIGARD WASHINGTON 97224 2.5 917.60 02/18/89 02/18/90 365 c TIGARD WASHINGTON 97224 156.60 2.1 02/14/89 04/27/89 72 c TIGARD WASHINGTON 97224 1.1 5.90 05/10/90 5 E KING CITY WASHINGTON 97224 4 05/15/90 1. 545.10 373 B 06/26/89 07/04/90 PORTLAND WASHINGTON 97224 1. 9 690.50 03/24/89 363 A TIGARD WASHINGTON 1. 5 03/22/90 97224 610.80 403 B 03/29/89 TIGARD WASHINGTON 97224 3.8 347.00 05/06/90 89 01/06/90 A TIGARD WASHINGTON 97224 0.1 17.90 04/05/90 91 c 01/13/90 TIGARD WASHINGTON 97224 0.8 319. 00 04/14/90 361 A PORTLAND WASHINGTON 97224 03/07/89 03/03/90 0.5 191.00 04/18/88 05/05/89 381 E KING CITY WASHINGTON 97224 0.7 67.50 12/23/89 03/23/90 90 E KING CITY WASHINGTON 97224 0.3 26.50 01/08/90 04/02/90 84 F TIGARD WASHINGTON 97224 0.3 2.70 01/11/89 01/19/89 8 TIGARD WASHINGTON 97224 321.60 0.8 08/19/88 08/30/89 375 c TIGARD WASHINGTON 97224 0.2 104.50 11/27/88 12/06/89 373 B TIGARD WASHINGTON 97224 0.7 66.90 01/10/90 04/12/90 92 F KING CITY WASHINGTON 97225 1.1 418.20 12/05/88 12/05/89 364 A PORTLAND WASHINGTON N 1--1 w Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97225 0.6 4.00 02/16/90 02/22/90 6 A PORTLAND WASHINGTON 97225 0.6 260.90 12/06/88 12/15/89 373 A PORTLAND WASHINGTON 97225 1. 2 470.10 10/10/88 10/10/89 364 D PORTLAND WASHINGTON 97225 1.2 467.30 12/15/88 12/23/89 372 J PORTLAND WASHINGTON 97225 3.3 838.90 08/19/88 04/29/89 252 A PORTLAND WASHINGTON 97225 1. 6 625.50 03/11/89 03/17/90 371 A PORTLAND WASHINGTON 97225 2.0 193.10 11/13/88 02/13/89 91 z PORTLAND WASHINGTON 97225 3.2 2489.40 04/10/88 05/18/90 767 F PORTLAND WASHINGTON 97225 1. 2 468.40 03/01/89 03/01/90 365 B PORTLAND WASHINGTON 97225 3.3 384.80 09/07/89 12/30/89 114 A PORTLAND WASHINGTON 97225 2.8 1003.40 11/27/88 11/13 /89 350 A PORTLAND WASHINGTON 97225 4.7 1 701. 50 02/24/89 02/20/90 361 A PORTLAND WASHINGTON 97225 0.4 185.10 01/09/89 02/06/90 393 A PORTLAND WASHINGTON 97225 4.2 1577.30 05/16/88 05/20/89 368 A PORTLAND WASHINGTON 97225 0.3 282.80 04/10/88 04/28/90 747 E PORTLAND WASHINGTON 97225 4.5 1666.40 11/25/88 11/25/89 364 z PORTLAND WASHINGTON 97225 9.4 3729.00 08/07/88 09/05/89 393 A PORTLAND WASHINGTON 97225 5.1 444.70 01/15/89 04/12/89 87 A PORTLAND WASHINGTON 97225 4.5 1684.40 09/27/88 09/30/89 367 A PORTLAND WASHINGTON 97225 17.5 84.90 01/02/89 01/07/89 5 A PORTLAND WASHINGTON 97225 2.6 964.70 05/16/88 05/20/89 368 B PORTLAND WASHINGTON 97225 0.5 51.10 12/26/89 04/06/90 101 c PORTLAND WASHINGTON 97225 1. 9 690.40 04/12/88 03/27/89 348 A PORTLAND WASHINGTON 97225 1. 7 388.60 01/11/90 08/18/90 219 B PORTLAND WASHINGTON 97225 1. 2 462.50 12/10/88 12/13/89 367 E PORTLAND WASHINGTON 97225 2.2 243.30 03/30/89 07/18/89 110 A PORTLAND WASHINGTON 97225 2.2 852.50 06/25/88 07/14/89 383 E PORTLAND WASHINGTON 97225 1. 2 937.20 04/10/88 05/18/90 767 A PORTLAND WASHINGTON ~ f--1 IP- Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97225 2.9 989.20 10/08/88 09/08/89 334 A PORTLAND WASHINGTON 97225 0.3 135. 90 04/09/88 05/22/89 407 c PORTLAND WASHINGTON 97225 3.5 1399.80 12/07/88 12/31/89 388 z PORTLAND WASHINGTON 97225 0.9 90 391. 04/11/88 05/23/89 406 A PORTLAND WASHINGTON 97225 1.7 576.30 04/12/88 03/09/89 330 G PORTLAND WASHINGTON 97225 1.2 108.50 03/08/89 05/31/89 84 A PORTLAND WASHINGTON 97225 1. 9 720.30 12/11/88 12/17/89 370 A PORTLAND WASHINGTON 97225 2.0 181.30 04/08/90 07/05/90 88 A PORTLAND WASHINGTON 97225 1. 2 421.90 03/03/89 02/10/90 344 A PORTLAND WASHINGTON 97225 0.4 202.20 04/23/88 09/10/89 504 B PORTLAND WASHINGTON 97225 0.6 250.60 12/06/88 12/15/89 373 A PORTLAND WASHINGTON 97227 0.2 89.60 03/15/89 03/27/90 377 J PORTLAND MULTNOMAH 97229 1.2 388.10 02/20/89 12/19/89 302 A PORTLAND MULTNOMAH 97229 0.3 146.90 03/05/89 03/17/90 377 F PORTLAND MULTNOMAH 97229 0.4 184.80 03/05/89 03/17/90 377 G PORTLAND MULTNOMAH 97229 0.7 294.10 05/01/88 05/08/89 371 c PORTLAND MULTNOMAH 97229 0.2 81.60 02/28/89 03/06/90 371 c PORTLAND MULTNOMAH 97229 0.5 213.40 02/22/89 03/03/90 374 A PORTLAND MULTNOMAH 97229 0.6 234.20 09/25/89 09/28/90 368 c PORTLAND MULTNOMAH 97229 0.6 83.20 01/11/90 05/20/90 129 A PORTLAND MULTNOMAH 97229 2.8 15.40 07/22/90 07/27/90 5 A PORTLAND MULTNOMAH 97229 0.6 88.40 04/02/89 08/21/89 141 B PORTLAND MULTNOMAH 97229 0.9 85.20 11/27/88 02/25/89 89 c PORTLAND MULTNOMAH 97229 2.6 538.60 05/15/89 12/06/89 205 H PORTLAND MULTNOMAH 97229 2.2 355.70 11/26/89 05/05/90 160 A PORTLAND MULTNOMAH 97229 1. 2 153.80 02/01/89 05/31/89 119 I PORTLAND MULTNOMAH 97229 3.2 1467.10 04/28/88 07/19/89 446 A PORTLAND MULTNOMAH 97229 3.1 1134. 40 09/15/88 09/12/89 361 E PORTLAND MULTNOMAH ~ I-' Ul Zip Code Date Concentration Total Start End Date Total Location a City County (pCi/l) Exposure days 97229 0.7 287.70 03/04/89 03/17/90 378 E PORTLAND MULTNOMAH 97229 1.0 386.30 12/0S/88 12/0S/89 364 D PORTLAND MULTNOMAH 97229 1. 6 S86. 30 07 /lS/89 07/04/90 3S4 J PORTLAND MULTNOMAH 97229 1. 0 143. so 01/28/90 06/10/90 133 A PORTLAND MULTNOMAH 97229 0.2 22.20 01/01/89 04/0S/89 94 A PORTLAND MULTNOMAH 97229 2.9 1082.70 09/28/89 09/28/90 36S C PORTLAND MULTNOMAH 97232 0. 6 244. 20 01/21/89 01/21/90 36S E PORTLAND MULTNOMAH 97232 0.7 272.70 10/20/88 10/23/89 367 A PORTLAND MULTNOMAH 97232 0. 7 277. 80 12/01/88 12/0S/89 368 A PORTLAND MULTNOMAH 97232 0.7 318.30 12/17/88 01/22/90 400 C PORTLAND MULTNOMAH 97232 1. 6 110. so 01/08/90 03/16/90 67 A PORTLAND MULTNOMAH 97232 0. 9 89. 70 02/06/90 OS/08/90 91 A PORTLAND MULTNOMAH 97232 1.1 392.90 OS/12/89 OS/02/90 3SS A PORTLAND MULTNOMAH 97232 3. 0 421.10 11/19/89 04/07/90 139 A PORTLAND MULTNOMAH 97232 2. 0 187. 80 04/09/89 07/08/89 90 A PORTLAND MULTNOMAH 97232 1. 0 140. so 11/0S/89 03/18/90 133 A PORTLAND MULTNOMAH 97232 4 .1 419. 20 12/lS/89 03/27/90 102 A PORTLAND MULTNOMAH 97232 4.S 2487.10 04/09/88 10/12/89 sso A PORTLAND MULTNOMAH 97267 0. 7 283. so 04/14/88 04/19/89 369 C MILWAUKIE CLACKAMAS 97267 0.3 1S4.70 10/10/88 12/0S/89 420 B MILWAUKIE CLACKAMAS 97267 2.2 842.30 04/07/88 04/20/89 377 E MILWAUKIE CLACKAMAS 97267 0. s 224. 30 01/18/89 01/29/90 376 A MILWAUKIE CLACKAMAS 97267 3.0 268.SO 01/11/90 04/10/90 89 A MILWAUKIE CLACKAMAS CLACKAMAS 97267 0. s 230. so 03/04/89 04/07/90 399 A MILWAUKIE CLACKAMAS 97267 1. 6 146 .10 02/14/89 OS/13/89 88 C MILWAUKIE 97267 0. 9 477. 60 03/21/89 07/13/90 479 A MILWAUKIE CLACKAMAS 97267 0. s 217. 30 03/01/89 03/19/90 383 L MILWAUKIE CLACKAMAS 97267 1. 2 111. 80 04/11/89 07/10/89 90 C PORTLAND CLACKAMAS N ~ O"I Zip Code Concentration Total Start Date End Date Total Location a City County (pCi/l) Exposure days 97267 2.3 865.80 01/09/89 01/09/90 365 A MILWAUKIE CLACKAMAS 97267 2.0 762.10 12/03/88 12/04/89 365 z OAK GROVE CLACKAMAS 97267 2.1 1373 .40 04/17/88 01/19/90 641 A MILWAUKE CLACKAMAS 97267 1.0 386.30 05/05/88 05/06/89 365 B MILWAUKIE CLACKAMAS 97267 1. 9 766.00 05/27/88 06/18/89 386 A MILWANKIE CLACKAMAS 97301 1. 2 454.10 10/18/88 10/21/89 367 A SALEM MARION 97301 0.5 192.30 01/26/89 01/24/90 363 B SALEM MARION 97301 1.3 127.80 03/23/89 06/26/89 95 c SALEM MARION 97301 0.3 123.20 01/26/89 01/24/90 363 B SALEM MARION 97301 1.2 458.20 11/28/88 11/24/89 360 A SALEM MARION 97301 0.6 235.00 03/29/89 04/04/90 371 A SALEM MARION 97301 1. 3 478.30 12/01/88 11/28/89 361 E SALEM MARION 1. 2 97301 457.60 11/30/88 12/14/89 378 A SALEM MARION 97301 0.3 150.30 04/12/88 07/25/89 468 A SALEM MARION 97301 1.0 390.70 03/18/89 03/18/90 365 B SALEM MARION 97301 0.8 292.70 01/26/89 01/24/90 363 B SALEM MARION 97301 1.1 423.40 10/11/88 10/11/89 364 B SALEM MARION 97301 3.6 1246.10 06/26/88 06/03/89 341 I SALEM MARION 97301 2.3 215.90 12/10/89 03/11/90 91 D SALEM MARION 97301 2.8 579.10 07/01/89 01/23/90 206 c SALEM MARION 97301 6.1 550.60 01/20/90 04/20/90 90 A SALEM MARION 97301 7.0 2547.80 11/30/88 11/27/89 361 A SALEM MARION 97302 1. 8 719. 50 05/16/88 06/05/89 384 J SALEM MARION 97302 2.4 937.00 12/05/88 12/17/89 376 A SALEM MARION 97302 0.2 28.50 01/15/90 04/23/90 98 c SALEM MARION 97302 2.2 412.40 10/14/89 04/14/90 182 A SALEM MARION 97302 12.5 5580.40 11/26/88 02/15/90 445 A SALEM MARION 97302 0.5 301.20 09/26/88 03/01/90 520 c SALEM MARION N 1-1 -...J Zip Code: Concentration Total a Start Date End Date Total Location City County (pCi/l) Exposure days ':173 02 2.2 801.00 12/02/88 12/01/89 363 A SALEM MARIOU 9 7 j 02 6.1 637.50 11/08/89 02/20/90 104 E SALEf.I !·!ARION 9 ·1j02 0.6 254.00 01/09/89 01/08/90 364 n SALEH f·IARIO!l 97302 2. 3 862.50 10/06/88 10/08/89 366 z SALEJ.I MARION si·1rn2 6.2 571.50 05/10/89 08/10/89 92 A SALE!·! f.IAIUO!J 97302 1.8 976.10 10/16/88 03/24/90 523 E SALEM MARION 97302 5.6 635.70 11/11/89 03/03/90 112 A SALEM J.IARION 9·13 02 0.6 63.60 04/23/89 08/06/89 105 A SALE!·! f.IARIO!l ~7302 5.5 2480.30 11/26/88 02/15/90 445 J SALEM f·lhRION 9·13 02 2.2 882.10 04/21/88 05/24/89 397 B SALEM l·lh.IUON 97302 ~.5 2030.50 02/23/89 02/23/90 365 D .Sl\I.Ef.I 1'1.1\RI O!J 97302 1.3 119.80 12/15/89 03/14/90 89 A SALE!·! 97302 2.6 M.L..RION 279.60 11/08/89 02/20/90 104 B SALEM MAI<.ION 97302 l.3 SBJ.90 10/13/88 12/18/89 430 c SALEM MAH.I Oil 97302 2.4 818.60 04/18/88 03/24/89 339 c SALEM f·IARIOtl 97302 l. 4 596.80 11/30/88 01/07/90 402 A SALEM 97302 M.l...F<.ION 9.9 902.40 06/15/89 09/14/8.9 91 I SALEM MARIUN 97302 0.9 Tl.10 02/18/90 05/14/90 85 E SALEM f.lhRIOIJ 97302 1 . 2 438.10 01/15/89 01/02/90 352 A SALEM MAI<.IOU N N 0