p.1 

OAR Box 1131 

Prepped by Ollie Stewart 

Document Number: 

123)11-1-401 

Docket Number: 

A-83-22 

Printed 4/21/2008 2:34:12 PM Sheet 123 of 162 
P.2 

V ^ <^P ^ 0*^ ^ 

ORNL/NSF/EATC-30 

Impact if a Lead Mining-Smelting Complex 

in I k 

Mew Leai lilt legion of SoofkasS Missouri 

A. P. Watson - R. I. Van Hook - D. R. Jackson - D. E. Reichle 

IM imp 

HI! r AR i htr ? 

EPA AIR DOCKET 

Environmental Sciences Division Publication No. 881 

* •"""^yjrnr^ 

OAK RIDGE NATIONAL LABQRATOR 

OPERATED BY UNION CARBIDE CORPORATION FOR THE ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATE ^ 

""Yjr'iTwiT 
P.3 
P.4 

ABSTRACT 

WATSON, Annetta P., R. I. VAN HOOK, D. R. JACKSON, and D. E. REICHLE. 

Impact of a lead mining-smelting complex on the forest-floor 

litter arthropod fauna in the New Lead Belt region of southeast Missouri. ORNL/NSF/EATC-30. Oak Ridge National Laboratory, Oak Ridge, Tenn. 167 pp. 

Studies of biological activity within the litter horizons of a 

watershed contaminated by emissions from a lead-ore processing complex 

focused on the litter-arthropod food chain as a means of detecting 

perturbations in a heavy-metal contaminated ecosystem. Both point 

sources (smelter stack emissions) and fugitive sources (ore-handling 

processes, yard dusts, and exposed concentrate piles) contributed to the 

Pb, Zn, Cu, and Cd levels in the study area (Crooked Creek Watershed, 

Iron County, Missouri, 37°38' N Lat., 91°07' Long.). Characterization 

of arthropod food base and habitat was accomplished by critical examination of litter mass, heavy metal and macronutrient content, cation 

exchange capacity, and pH. Arthropodtrophic lj?yel density, biomass, 

and heavy metal content were determined by analysis of specimens removed 

from litter by von Tullgren funnel extraction, taxonomically classified, 

and segregated into the trophic categories of detritivore, fungivore, 

littergrazer, omnivore, and predator. 

The highest concentration of litter Pb, Zn, Cu, and Cd occurred in 

02 litter. Mean values of 103000 ppm Pb, 4910 ppm Zn, 6080 ppm Cu, and 

179 ppm Cd were found in samples collected 0.4 and 0.8 km from the 

smelter. These elevated concentrations were strongly correlated (P<.01) 

with an accumulation of undecomposed 02 material. The mean annual 02 

mass/m found 21.0 km W of the smelter (control area) was 1030+126 (SE) 

g/m2 as compared to 2198+201 (SE) and 1765+142 (SE) g/m2 for the 6.4 and 
P.5 

0.8 km sites, respectively. The mean annual mass of 01 material did not 

differ significantly throughout the study area, but varied about a mean 

of 433+29 (SE) g/m (ranging from 120 to 480 g/m2 ). Mean annual 01 mass 

at the control area was 471+34 (SE) g/m . 

Changes in litter decomposition were reflected in the dynamics of 

the litter arthropod community. Reduced values of total arthropod 

2 2 

density (no/m ) and biomass (mg/m ) occurred simultaneously with elevated 

concentrations of Titter heavy metals. This reduction in total arthropod 

biomass and density was governed by a decrease in biomass and density of 

the predator, detritivore and fungivore populations. In addition, 

measurements of arthropod richness, an estimate of maximum diversity, 

revealed that litter arthropod populations at heavily contaminated sites 

were less rich in taxa (family) than were those located elsewhere on the 

watershed. 

Food-chain dilution of Pb, Zn, Cu, and Cd from litter to litter 

consumer was occurring, as indicated by the mean concentration factors 

of 0.07+0.02 (Pb), 0.64+0.15 (Zn), 0.38+0.10 (Cu), and 0.34+0.05 (Cd). 

Accumulation of Pb by litter consumers was much less than that found for 

the other three heavy metals. Tn contrast, predatory arthropods on 

Crooked Creek Watershed either concentrated or equilibrated with respect 

to Pb, Zn, and Cd from their prey, as indicated by mean total predator 

concentration factors of 1.16+0.29 (Pb), 1.27+0.14 (Zn), and 1.27+0.02 

(Cd). Of all four heavy metals, only Cu appeared to be diluted by foodchain transfer from prey to predator (x = 0.67+0.10). 

Measurements of fresh foliage and litter macronutrient concentrations and litter macronutrient pools indicated that forest-nutrient 

dynamics on Crooked Creek Watershed were seriously disturbed. Asigni-^ 

fi cant Regression (P<.Q5) of the Ca, Mg, and K content of 01 and 02 

vi 
P.6 

1 itter occurred relative to the rnntrnl within O.R km nf thfl stark Two 

mechanisms were postulated to explain this result: 

(1) Increased leaching of cations through the litter induced 

by a loss of cation exchange capacity, a decrease in pH, 

and a decrease in microbial immobilization of macronutrients. 

(2) A decreased uptake of macronutrients due to root damage 

produced by heavy-metal concentrations. The result would 

be a reduced annual macronutrient input from litterfall. 

A loss in litter cation exchange capacity and reduction in fresh-foliage 

macronutrient content was measured on the Crooked Creek Watershed. An 

accumulation of macronutrient pools in 02 litter also existed between 

1.2 and 2.0 km of the smelter. 

vi 1 
P.7 

-• --t-^rTTT' t'VWTTT Tl 

ORNL/NSF/EATC-30 

Contract No. W-7405-eng-26 

IMPACT OF A LEAD MINING-SMELTING COMPLEX ON THE FOREST-FLOOR 

LITTER ARTHROPOD FAUNA IN THE NEW LEAD BELT REGION 

OF SOUTHEAST MISSOURI 

A. P. Watson, R. I. Van Hook, D. R. Jackson, and D. E. Reichle 

ENVIRONMENTAL SCIENCES DIVISION 

Submitted by A. P. Watson as a dissertation to the 

Graduate School of the University of Kentucky 

in partial fulfillment of the requirement 

for the degree of Doctor of Philosophy 

Environmental Sciences Division Publication No. 881 

Work supported by the National Science Foundation -- RANN Environmental 

Aspects of Trace Contaminants Program under NSF Interagency Agreement 

AEN 72-01243A03 with the Energy Research and Development Administration. 

JULY 1976 

OAK RIDGE NATIONAL LABORATORY 

Oak Ridge, Tennessee 37830 

operated by 

UNION CARBIDE CORPORATION 

for the 

ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION 
P.8 

ACKNOWLEDGMENTS 

This research was supported by the National Science FoundationRANN Environmental Aspects of Trace Contaminants Program under NSF 

Interagency Agreement AEN 72-10243A03 with the Energy Research and 

Development Administration. The author performed the research at the 

Oak Ridge National Laboratory (ORNL, operated by Union Carbide 

Corporation for the Energy Research and Development Administration) 

while under appointment to the Laboratory Graduate Participant Program 

administered by Oak Ridge Associated Universities. 

The cooperation of the AMAX-Homestake Smelting Company personnel 

is gratefully acknowledged. Special thanks is due George Carr, 

environmental engineer for the smelter operation near Bixby. 

Particular recognition is due John Wright, who cheerfully supplied 

invaluable field assistance on Crooked Creek Watershed. Omer Phillips 

provided much-appreciated technical support in the preparation of 

litter samples for heavy metal analysis. Statistical advice and 

counseling on experimental design and analytical procedures were 

capably furnished by John Beauchamp, Ron Hiltunen, and Rod Strand of 

the Data Resources Group (ORNL). Neil Griffith and Jerry Raine, 

operators of the Remote Batch. Station Facility (ORNL), provided helpful 

programming assistance and ran the numerous jobs submitted. 

We also wish to thank Dr. J. G. Rodriguez, Dr. B. C. Pass, 

Dr. P. H. Freytag, Dr. J. E. Leggett, Dr. J. A. Sayeg (University 

of Kentucky), and Dr. W. F. Harris (ORNL) for critical evaluation 

of the manuscript. 

m 
TABLE OF CONTENTS 

T" "T»""T«f "'' - "TtTfTf'""" 

Page 

P.9 

ACKNOWLEDGMENTS 

ABSTRACT , 

LIST OF TABLES 

LIST OF FIGURES 

LIST OF APPENDICES . 

INTRODUCTION 

MATERIALS AND METHODS 

Study Area 

Sampling Procedures 

Location of Study Plots 

Litter Sampling and Initial Processing . . 

Arthropod Sampling and Initial Processing 

Analytical Procedures 

Heavy Metals 

Chemical Characterization of Litter . . . 

Arthropod Diversity Measurement 

Arthropod Population Density and Biomass . 

Statistical Procedures 

RESULTS AND DISCUSSION 

Crooked Creek Watershed Litter 

Litter Mass 

Litter Heavy Metal Content 

Litter Heavy Metal Pool 

Chemical Characterization of Litter . . , 

Arthropods .... . 

Population Density and Biomass , 

Heavy Metals 

Concentration Factors . 

Diversity 

m 

xi 

xv 

xv ii 

1 

4 

4 

7 

7 

8 

13 

14 

14 

15 

16 

17 

18 

20 

20 

20 

25 

40 

44 

52 

52 

61 

66 

76 

IX 
P.10 

GENERAL DISCUSSION 

Heavy Metal Effects on Biota 

Mineral Cycling 

SUMMARY AND CONCLUSIONS 

APPENDICES 

Appendix A 

Appendix B 

Appendix C 

Appendix D 

REFERENCES CITED 

Page 

81 

81 

86 

89 

93 

94 

101 

129 

138 

151 

•PBBIpgij,j..jjijUJJi 
LIST OF TABLES 

Table 

1. 

2. 

7. 

9. 

10. 

Page 

11 

22 

Watershed 02 litter mass (g/m , transformed by Eqn. 3) 

(n = 174, F23 15 0 = 3.838, R2 = 0.370). 

Correlation matrix resulting from multiple linear 

regression analysis of Crooked Creek Watershed 02 

litter mass (g/m2, transformed by Eqn. 3) (n = 174, 

F23 150 = 3 '838 ' R = °-3 7°)-

Multiple linear regression statistics for Crooked 

Creek Watershed 02 litter mass (g/m2, transformed by 

Eqn. 3) and independent variables selected by the 

backward elimination procedure at P = 0.25 (n = 174, 

F14 159 = 6 '344 ' R 2 = °-358 )-

Comparison of Pb, Zn and Cd concentrations (ppm) in 

Walker Branch Watershed and Crooked Creek Watershed 

leaf litter and soils. 

September means of 01 heavy metal pools analyzed by 

Duncan's New Multiple Range Test. Means followed 

by the same letter are not significantly different 

at the 5% level. 

September means of 02 heavy metal pools analyzed by 

Duncan's New Multiple Range Test. Means followed by 

the same letter are not significantly different at 

the 5% level (Duncan, 1951; Steel and Torrie, 1960). 

23 

Landscape characters and dominant vegetation of 

Crooked Creek Watershed study sites. 

Seasonal means of 01 litter mass analyzed by Duncan's 

New Multiple Range Test. Means followed by the 

same letter are not significantly different at the 

5% level (Duncan, 1951; Steel and Torrie, 1960). 

Seasonal means of 02 litter mass analyzed by Duncan's 

New Multiple Range Test. Means followed by the 

same letter are not significantly different at the 

5% level (Duncan, 1951; Steel and Torrie, 1960). 

Seasonal mean ash content {% dry wt) of Crooked Creek 

Watershed litter. One standard error in parentheses 

(n=3). The NW transect was chosen as representative 

of the watershed. 

Multiple linear regression statistics for Crooked Creek 36 

26 

38 

39 

41 

42 

43 

XI 

!i«y»>J! 
P.12 

Table 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

18. 

19. 

20. 

Cation exchange capacity and pH of 02 litter on 

Crooked Creek Watershed (NW transect). 

Mean macronutrient concentration in oak leaves on 

Crooked Creek Watershed in relation to distance 

from the smelter (n=6). 

Macronutrient pools of 02 litter on Crooked Creek 

Watershed (NW transect). 

Seasonal mean arthropod biomass (mg dry wt/m2) in 

the litter 02 horizon of Crooked Creek Watershed. 

One standard error in parentheses (n=4). 

Seasonal mean arthropod density (no./m2) in the 

litter 02 horizon of Crooked Creek Watershed. One 

standard error in parentheses (n=4). 

Mean annual Crooked Creek Watershed 02 litter 

arthropod predator, detritivore and fungivore biomass 

(mg dry wt/m2) and density (no./m2). Seasons have 

been pooled as replicates. Values in parentheses are 

1 standard error (n=16). 

Multiple linear regression statistics for Crooked 

Creek Watershed 02 litter arthropod biomass (mg/m2, 

transformed by Eqn. 3) (n = 176, F«- ,co = 6.931, 

R

2

 = 0.512).

 23'152 

Correlation matrix resulting from multiple linear 

regression analysis of total arthropod biomass (mg/nr, 

transformed by Eqn. 3) found on Crooked Creek Watershed 

(n = 176, F2 3 152 = 6.931, R2 = 0.512). 

Multiple linear regression statistics for Crooked 

Creek Watershed 02 litter arthropod biomass (mg/m2, 

transformed by Eqn. 3) and independent variables 

selected by the backward elimination procedure at 

P = 0.25 (n = 176, F1 4 ]61 = 10.178, R2 = 0.507). 

Lead concentrations (yg/g dry wt) found associated 

with arthropod trophic levels on Crooked Creek 

Watershed. Specimens from both litter horizons, 

all seasons, and all replicates were pooled for 

chemical analysis (n=32). 

xii 

""H'TT" '"'

 T""'r 

Page 

47 

48 

51 

53 

54 

55 

58 

59 

60 

63 

1 
1 "TTT"r""!,""ff¥!"f ""' 

P. 13 

Table 

21. 

22. 

23. 

24. 

25. 

26. 

27, 

28. 

Zinc concentrations (yg/g dry wt) found associated 

with arthropod trophic levels on Crooked Creek 

Watershed. Specimens from both litter horizons, 

all seasons, and all replicates were pooled for 

chemical analysis (n=32). 

Copper concentrations (yg/g dry wt) found associated 

with arthropod trophic levels on Crooked Creek 

Watershed. Specimens from both litter horizons, 

all seasons, and all replicates were pooled for 

chemical analysis (n=32). 

Cadmium concentrations (yg/g dry wt) found associated 

with arthropod trophic levels on Crooked Creek 

Watershed. Specimens from both litter horizons, 

all seasons, and all replicates were pooled for 

chemical analysis (n=32). 

Weighted concentration factors calculated for Pb 

transport in the Crooked Creek Watershed litterarthropod food chain. 

Weighted concentration factors calculated for Zn 

transport in the Crooked Creek Watershed litterarthropod food chain. 

Weighted concentration factors calculated for Cu 

transport in the Crooked Creek Watershed litterarthropod food chain. 

Weighted concentration factors calculated for Cd 

transport in the Crooked Creek Watershed litterarthropod food chain. 

Crooked Creek Watershed litter arthropod diversity 

indices for each site, horizon and season: 

a. Shannon-Weaver Index, H' (calculated by 

Equation #1) 

b. Pielou's evenness index, J' (calculated by 

Equation #2) 

c. Richness index, S (total number of families) 

Page 

64 

65 

67 

69 

70 

71 

72 

77 

x m 
P.14 

LIST OF FIGURES 

Page 

Fig. 1. Location of Dent and Iron Counties in Missouri. 5 

Crooked Creek Watershed is in Iron County, 38 km 

east of Salem. 

Fig. 2. Topography and vegetation of Crooked Creek Watershed. 6 

State roads J, 32, and the St. Louis-San Francisco 

railway form the W, N, and NE boundaries, respectively. 

Fig. 3. Wind-rose patterns at the AMAX-Homestake smelter stack 9 

for Fall and Winter, 1970 and Spring and Summer, 1971. 

Data taken from Wixson, ejt al_., 1972. 

Fig. 4. Sampling grid utilized on Crooked Creek Watershed for 10 

collection of litter and arthropods in the present 

study. Crooked Creek Watershed, a 466 ha. portion 

of the Clark National Forest, is located in Iron 

County, Missouri. 

Fig. 5. Mean litter mass (g dry wt/m") of 01 and 02 horizons 21 

on Crooked Creek Watershed as a function of distance 

and direction from the AMAX smelter for the September, 

1974, sampling period (x +_ 1 SE, n=4). 

Fig. 6. Pooled means of litter mass (g dry wt/m ) of 01 and 02 24 

horizons on Crooked Creek Watershed as a function of 

distance from the AMAX smelter for each sampling period, 

1974. Values for the NE transect were excluded from 

computation of the means (x + 1 SE, n=12). 

Fig. 7. Means of litter Pb content (yg/g dry wt) in 01 and 02

 2 8 

horizons as a function of distance and direction from 

the AMAX smelter for the September, 1974, sampling 

period (x +_ 1 SE, n=4). 

Fig. 8. Means of litter Zn content (yg/g dry wt) in 01 and 02 29 

horizons as a function of distance and direction from 

the AMAX_smelter for the September, 1974, sampling 

period (x +_ 1 SE, n=4). 

Fig. 9. Means of litter Cu content (yg/g dry wt) in 01 and 02 30 

horizons as a function of distance and direction from 

the AMAX smelter for the September, 1974, sampling 

period (x +_ 1 SE, n=4). 

Fig. 10. Means of litter Cd content (yg/g dry wt) in 01 and 02 31 

horizons as a function of distance and direction from 

the AMAX smelter for the September, 1974, sampling 

period (x +_ 1 SE, n=4). 

xv 

WgjBj|Wg^L^l^lltll^

li'-'.-'tiV-'-W?T^° 
•> -m -T- T ^ * T'"PJ||,|If 

P.15 

"Tpj 

Fig. 11. Pooled means of litter Pb, Zn, Cu, and Cd concentrations 

(yg/g dry wt) as a function of distance from the AMAX 

smelter for September, 1974. Values for the NE transect 

were excluded from computation of these means (x + 1 SE, 

n=12). 

Page 

34 

Fig. 12. Mean macronutrient concentrations of Ca, Mg, K, and P 

(+_ 1 SE, n=12) in Crooked Creek Watershed litter as a 

function of distance from the AMAX smelter. Data from 

Jackson and Watson, 1976. 

45 

Fig. 13. Mean macronutrient pool sizes of Ca, Mg, K, and P 

(+_ 1 SE, n=12) in Crooked Creek Watershed litter as 

a function of distance from the AMAX smelter. Data 

from Jackson and Watson, 1976. 

50 

xvi 
P.16 

LIST OF APPENDICES 

Appendix 

Trophic-level assemblage and abundance of arthropod 

taxa (excluding Acarina) found on Crooked Creek 

Watershed during the study year (1974). 

Listing of all arthropod data collected from Crooked 

Creek Watershed litter by taxon, season, site, 

horizon, and lifestage. Trophic level designations 

were referenced in Appendix A. 

Seasonal means of heavy metal content (Pb, Zn, Cu, 

and Cd) ranked according to results of Duncan's New 

Multiple Range Test. 

Pooled, seasonal means of litter Pb, Zn, Cu, and 

Cd content (yg/g dry wt) as a function of distance 

from the smelter. Values for the NE transect were 

excluded from computation (x + 1 SE, n=12). 

Page 

94 

101 

129 

138 

x vn 

* 
"•^^TM~ -pm 

INTRODUCTION 

Lead presently occurs as a global pollutant (Committee on Biologic 

Effects of Atmospheric Pollutants, 1972) but few references are 

available documenting the effects of Pb sources on litter arthropods. 

Preliminary evidence exists to suggest possible transfer of elemental 

Pb through plant-herbivore-carnivore food webs from roadway "line 

sources" (Giles, e_t al_., 1973; Rolfe et^ aj_., 1974). No study yet 

published has attempted to document such biological transfer within a 

litter system, although it has been shown that litter-grazing isopods 

collected from roadside ditchbanks contain significantly elevated 

concentrations of Pb relative to values found in predaceous spiders or 

opilionids (Williamson and Evans, 1972). As no heavy metal analysis 

of the decaying vegetation was made, concentration factors could not 

be calculated from Williamson and Evans' data. In contrast, no difference could be detected in distribution or abundance of identical taxa 

found at sites ranging in total soil-lead content from 70 ppm (roadway 

ditchbank) to 19000 ppm (overgrown lead-mine spoil heaps) (Williamson 

and Evans, 1973). However, neither tissue-lead nor litter-substrate 

lead analyses were performed. 

It is well known that the seasonal uptake of nutrients in deciduous forests depends upon mineralization of litter by saprovore populations (Ovington, 1960; Witkamp and Ausmus, 1975). It is also known 

that litter can serve as a heavy metal reservoir by chelation or cation 

exchange processes (Ruhling and Tyler, 1973; Hirst, et. aj_., 1961). 

Because disruption of decomposition can affect the forest ecosystem by 

accelerated nutrient losses and reduced mineralization rates (Tyler, 

1 
P.18 

1972), examination of heavy-metal effects on the litter community is 

important in fully understanding basic ecosystem processes. 

In unperturbed ecosystems, arthropods of the litter community act 

as "catalysts of microbial metabolism" (Macfadyen, 1963) in the decomposition processes. Passage of litter through the arthropod gut produces a substrate favorable to microbial decomposition via fragmentation 

and chemical alteration (Nicholson, e_t aj_., 1966; van der Drift and 

Witkamp, 1960; McBrayer and Reichle, 1971). Such substrate modification 

supports the hypothesis that these animals may act as decomposition 

rate regulators (McBrayer, 1973). 

Dispersal and growth of microorganisms is also aided by the 

physical presence of arthropods. Inoculation of litter substrate can 

occur from spores transported on spines, setae and appendages (Szabo, 

1974; Witkamp, 1960) or in fecal deposits (Macfadyen, 1968). Microhabitats for bacterial and fungal multiplication are produced by 

arthropod burrowing activities (Szabo, 1974). 

In short, litter arthropods and decomposer microorganisms are 

inseparably linked in the breakdown of non-living plant material. Any 

perturbation uncoupling the close associations in the decomposer 

community will have an effect on the release of nutrients from litter. 

The primary objective of the present study was to determine the 

degree to which lead can be biologically transported by the principal 

arthropod food chains present in a forest-floor litter community 

subjected to heavy-metal contamination. To accomplish this goal, it 

was also necessary to physically and chemically characterize the litter 

habitat. 
P.19 

The study area chosen was a southeastern Missouri watershed receiving stack emissions and fugitive source dusts originating from an 

adjacent primary lead smelteropgrated bv the AMAX and Homestake Smelting 

Companies since 1968. The watershed is unique in that the woodland 

ecosystem is largely intact, having sustained little damage due to the 

extensive lumbering, burning, and soil erosion that characterizes many 

other smelter sites (Jordan, 1971, 1973, 1975; Witkamp e_t aJL, 1966). 

In addition, periodic monitoring of smelter emissions^i^ositeT^on the 

watershed has been made since 1971 (Wixson e_t aj_., 1972; Wixson, 1974). 

Due to the presence of heavy metals other than Pb in source dusts, 

all samples were analyzed for Zn, Cu, and Cd as well as Pb to examine 

for possible synergistic or additive effects on biological transport. 
P.20 

MATERIALS AND METHODS 

Study Area 

The study area is a 466 ha. watershed located in the Clark 

National Forest, Iron County, Missouri (37°38' N Lat., 91°07' Long.) 

(Fig. 1). Named for its main drainage, Crooked Creek Watershed (CCW) 

lies on the now deeply dissected remnants of the Salem Plateau. Local 

topography (Fig. 2) is characterized by hills alternating with steep 

valleys (Schwarz and Schwarz, 1959). The second-growth canopy species, 

black oak (Quercus velutina Lam.), white oak ((}. alba L.), northern 

red oak (Q. boreal is Michx.), post oak ((£. stellata Wang), and blackjack oak (C[. marilandica Muenchh), provided 74+5% (SE) of the total 

canopy biomass. Shortleaf pine (Pinus echinata Mill.) provided 

16+6% of the total canopy biomass (Dixon, 1974). 

Watershed soils were thin, stony, limestone-residual, cherty 

silt loams. Ridgetops possessed a Lebanon soil type with a 5-8 cm 

fragipan; slope soils were dominated by cherty silt loams of the 

Wilderness (40%) and Clarksville (25%) series. Valley floors were 

occupied by alluvial Razort and Ashton soils (Kickbush, 1975). 

Soil Conservation Service data from neighboring Dent County 

indicated a mean annual rainfall of 106.7 cm with 31% of the precipitation received in the spring (March-May), 51% in the summer (JuneAugust) and fall (September-November), and 18% during the winter 

(December-February). Mean temperatures in Dent County ranged from 

0.6°C in January to 25.5°C in July. There were an average of 177 

frost-free days per year (Gilbert, 1971). 
r iy>^".M'. '•'* ' M* ' "» mm*mmnjmmmmmi**1* 

ORNL-DWG 76-2637 

IRON COUNTY 

DENT COUNTY 

Fig. 1. Location of Dent and Iron Counties in Missouri. Crooked Creek 

Watershed is in Iron County, 38 km east of Salem. 

en 
T W = "x^-*TTTn 

ORNL DWG 75-15802 

Fig. 2. Topography and vegetation of Crooked Creek Watershed. State 

roads J, 32, and the St. Louis-San Francisco railway form the 

W, N, and NE boundaries, respectively. 
P.23 

Crooked Creek Watershed has been subject to intermittent grazing by 

cattle, sheep, and hogs both prior to, and following, purchase by the 

U.S. Forest Service for inclusion in the National Forest System in the 

1930's (Wright, 1974). Although the original Forest Service management 

scheme called for multi-purpose use, the area has become the site of 

lead/zinc mining, milling, and smelting activity since the discovery of 

rich deposits near Viburnum (8 km N of CCW) in 1955. The "Viburnum 

Trend" is now acknowledged to be the largest and richest known lead 

deposit in the world (Missouri Division of Geological Survey and Water 

Resources, 1971, 1974). 

A numberO_f heaw mP^a] gnnrrn<- rwir t n>ni- ri-nnk-nri Pi.nok^Ula torched 

AMAX Lead Co. of Missouri, in cooperation with Homestake Mining Co., has 

managed a primary lead smelter at the apex of the triangularly-shaped 

waTer*shed Since 1968~! A mine-mill complex operated by COMINCO~HliieTican 

transports Pb, Zn and Cu concentrate along the St. Louis-San Francisco 

railway forming the northeastern boundary of the watershed (Fig. 2). 

Until 1974, loaded railroad cars were not covered, and their dry contents 

were readily blown into the study area (Wright, 1974). Exposed piles of 

Cu concentrate adjacent to the railway also serve as source areas. 

Thus, both point sources (smelter stack emissions) and fugitive sources 

(ore-handling processes, yard dusts, and exposed concentrate piles) 

contributed to the heavy-metal load on the watershed. 

Sampling Procedures 

Location of Study Plots 

Seasonal means of wind-rose patterns were used to develop a field 

sampling grid on directional transects originating from the base of the 
8 

smelter stack (Fig. 3). In accordance with United States Forest Service 

permanent plot inventory procedures, 0.04 ha (0.1 A) study plots (Fig. 4) 

were established at 0.4 km (0.25 mi) intervals along each transect 

(Clark National Forest, 1972). The one exception was the placement of 

the third plot on the NE transect 100 m from the second. The location 

of the St. Louis-San Francisco railway along the eastern ridgetop 

boundary prevented the location of this site exactly 1.2 km from the 

stack base. 

A grid incorporating 32 sites on 7 transects was employed during 

initial sampling in September and December, 1973. Results from these 

sampling periods indicated that no significant differences in heavy 

metal content or litter mass exist between not only the 1.6 and 2.0 km 

sites, but also between the WNW-NW, NNW-N, and NNE-N transects. A 

refined grid incorporating 15 sites on 4 transects was used for the oneyear (1974) field sampling reported in this study (Fig. 4) . 

A tree, conspicuously marked with flagging tape and an aluminum 

identification tag, designated the center of each 0.04 ha study plot. 

The slope and aspect of each plot were measured with a Haga altimeter 

and surveyor's compass. Elevation measurements were derived from 

altimeter readings corrected for barometric pressure fluctuations by 

periodic monitoring at several U.S.G.S. benchmarks in the area. A plot 

summary of landscape characteristics and dominant overstory species is 

given in Table 1. 

Litter Sampling and Initial Processing 

The Soil Science Society of America recognizes two litter horizons, 

01 and 02. Plant material of the 01 layer has retained its original 

mm wmmm 
n 

F

»EQUENCV (% 

j CAL-M 1— 

0 ? 

1 ' 

. 0»p»t 

• i *-T »-<2 •)••» •»-.?« 

UMNO S»CCD .">oM 

4 6 9 ' 0 '? 

1 1 1 , 1 1 

•0*C ' 

••?) 

• 4 

-J 

«-«•',• 

4 

Jf 

1 

Wmo ftoso or AMAX Sm.lrtr in Spring S.OSOn 1971. 

*">a R0 ,t o t iMa x 

Sm.lr.r l 0 , Summ., ,97,. 

W.na Ro „ 0, AMAX S»,l„ , ,„ , Fo „ s , „ o n 4 ,,, „ 

F

i g . 3. Wind-rose patterns at the 

*'* 0 SPEED imem 

0

 * * « « '0 .1 „ Jt 

*<"0 Ro>t or AMAX S mt)f „ f0f 

Winter S«o»on, I97Q. 

Efrom Wixson S«j , e_t aj_.f, 1972 S. Kri^ wData take; n 
4 

A 

TO BOSS 

CROOKED 

ORNL-DWG 74-3931 

-TO BIXBY 

PRIVATE ROAD 

MAGMONT MINE 

(COMINCO) 

Fig. 4. 

TAILINGS 

POND 

LOUIS-SAN FRANCISCO RR 

Sampling grid utilized on Crooked Creek Watershed for collection of litter and arthropods in the present study. Crooked 

Creek Watershed, a 466 ha. portion of the Clark National 

Forest, is located in Iron County, Missouri. 

ho 

0) 
•-T5 *T»rT w -• imnfTCTf" -v - "Tl 

11 

Table 1. Landscape Characters and Dominant Vegetation of Crooked 

Creek Watershed Study Sites. 

Site* Slope Aspect Elevation 

(km) (%) (Q) (m) 

Dominant Species 

W 0.4 12.5 240 422.7 Queraus stellata Wang 

Q. marilandioa Mueunchh. 

W 0.8 11.5 126 418.5 Q. alba L. 

Pinus echinata Mill 

W 1.2 5.5 53 403.5 Q. velutina Lam. 

Q. stellata 

Q. alba 

W 1.6 10.5 266 414.8 Q. alba 

Q. stellata 

Q. velutina 

NW 0.4 7.5 290 401.7 Q. alba 

Q. aoacinea 

Q. velutina 

v--

NW 0.8 11.5 40 398.9 Q. borealis Michx. 

Q. stellata 

Q. velutina 

1.2 

NW 2.0 

40 390.1 

382.8 

Q. stellata 

Q. velutina 

Carya texana Buckl. 

Q. stellata 

C. tomentosa (Poir.) 

Crataegus spp. 

Juniperus virginiana 

Salix spp. 

N 

N 

N 

N 

0.4 

0.8 

1.2 

2.0 

18 

9 

24 

7 

290 

290 

65 

270 

423.0 

421.5 

392.5 

401.7 

Q. alba 

Q. velutina 

Q. Velutina 

Q. alba 

Q. borealis 

Q. alba 

Q. stellata 

Q. velutina 
••rw

r

'i*-vrrrw P.28 

12 

Site* 

(km) 

NE 0.4 

NE 0.8 

NE 1.2 

Slope 

11 

12 

24 

Aspect 

(°) 

310 

270 

65 

W 10.5 11.5 185 

(secondary control) 

W 16.4 8.5 330 

(secondary control) 

W 21.0 

(control) 

9.5 120 

Elevation 

(m) 

413.0 

417.9 

392.5 

384.7 

424.0 

395.6 

Dominant Species 

Q. 

Q. 

Q. 

Q. 

Q. 

Q. 

Q. 

C. 

Q. 

C. 

alba 

velutina 

alba 

borealis 

alba 

marilandioa 

stellata 

velutina 

tomentosa 

alba 

velutina 

texana 

Q. stellata 

Q. velutina 

Carya ovalis (Wang.) 

*See Fig. 4 
,-T,, ,.-.,pr13 

conformation. Material of the 02 layer is fragmented and no longer 

recognizable as to species or origin (Black, 1965). In the present 

study, four replicate samples of both litter horizons were randomly 

collected at each watershed site and at one control site 21.0 km west 

of the smelter area during March, June and September of 1974 and January 

of 1975. Each pair of samples included all litter within a 0.1 m area. 

To reduce edge effect and facilitate cutting through leaves and stems, 

a circular frame of stainless steel with a sharpened edge was used 

(Medwicka-Kornas, 1971; McBrayer et al., 1974). Additional collections 

were made at 10.5 and 16.4 km west of the smelter area in September 

2 

and January to establish a measure of the gradient in litter mass/m 

with distance. The September samples were collected prior to leaffall. 

In 1974, leaffall occurred in mid-October (Drobney, 1974). 

Following transport to the laboratory and extraction of arthropods, 

the litter was hand-sorted to remove rock, oven-dried at 100°C to constant moisture, and weighed to the nearest 0.1 gm. 

Arthropod Sampling and Initial Processing 

Field-collected litter was placed into polypropylene bags and 

transported to Oak Ridge National Laboratory in styrofoam coolers 

packed with ice to maintain 5°C, a storage temperature suitable for 

arthropod survival (Edwards and Fletcher, 1971). Samples were held 

at 5°C in controlled-environment chambers at the laboratory (7-10 da) 

until arthropods could be removed by 72-hour von Tullgren funnel extraction. Arthropods were collected in an aqueous solution of 70% ET0H and 

5% glycerin, identified, and stored in 70% ET0H for further processing 

(Macfadyen, 1955, 1962). 
P.30 

14 

All preserved arthropods, except Acarina, were classified to family 

and enumerated by taxon and replicate per site for later analysis. An 

adequate measure of Acarine population density and biomass in a natural 

system is a project requiring separate study (McBrayer e_t al_., 1974), 

and was therefore not attempted in the present research. To prevent 

difficulties arising from attempting to dry specimens stored in dilute 

alcohol containing glycerine, specimens were transferred from the von 

Tullgren vials to holding vials containing 70% ethanol only. Samples 

were then dried in these latter containers. Average dry weights of 

each lifestage of every taxon found on Crooked Creek Watershed were 

calculated from individual determinations of 4-20 specimens dried at 

70°C for 24 hours and weighed to the nearest 0.00001 g. Literature 

documentation was used to segregate taxa into the trophic categories 

detritivore, fungivore, littergrazer, omnivore, and predator (see 

Appendix A) . 

Analytical Procedures 

Heavy Metals 

Subsamples of each litter" replicate were ground to #20 mesh 

fineness in a Wiley mill and wet-digested by treatment with 1:1 HN03/ 

HC104 (Smith, 1953; Analytical Methods Committee, 1960; Gorsuch, 1962). 

Upon attaining complete digestion, each sample was suspended in 1 N_HC1, 

heated at 100°C for 10 minutes, filtered through #40 Whatman paper, 

and analyzed by atomic absorption spectrophotometry for total Pb, Cd, 

Zn, and Cu content. Analytical grade reagents were used. All preparation methods and analytical procedures were monitored periodically utilizing coded blanks and a NBS-SRM-1571 standard (orchard leaves). 
P.31 

15 

Analytical results for the standards were accurate to within one 

standard error of the mean. 

Dried arthropods of individual trophic levels from each of two 

randomly selected replicates were pooled across season and horizon, 

and dry-ashed for 24 hours at 480°C - a temperature which prevents lead 

volatilization (Gorsuch, 1962). The remaining ash was suspended in 

0.1 N^ HN03 and allowed to stand undisturbed for 24 hours at room temperature. The decant was analyzed for total Pb, Cd, Zn, and Cu content 

by graphite furnace atomic absorption spectrophotometry. Monitoring of 

preparation and analytical procedures was performed frequently using 

coded blanks and NBS-SRM-1577 standard (bovine liver) as previously 

discussed for litter samples. 

Chemical Characterization of Litter 

Approximately 1.0 g samples of dried, ground litter collected from 

the NW transect were dry-ashed overnight at 550°C. Five ml of concentrated HN03 were added to the ash and samples were boiled to dryness. 

Exactly 50.0 ml of 1.0 N[ HCl were added to the residue, and any undissolved residue was allowed to settle to the bottom of the container. 

An aliquot of each sample was analyzed by atomic absorption spectrophotometry for total elemental Ca, Mg, and K. Phosphorus was determined 

by the automated Technicon method (Lundgren, 1960). 

Litter cation exchange capacity (Francis and Grigal, 1971) was 

85 determined using 25 ml of 1 N SrCl2 in a suspension of 1.0 g ground 

litter. The suspensions were shaken overnight, centrifuged, and 

decanted. The litter was then sequentially washed with 25 ml each of 

the following solutions: distilled water, a 50:50 mixture of ET0H and 

1 
-"•Tr-'TfrTn* 

16 

distilled water, and 2 washes in 95% ETOH. The washed litter was 

OC 

subsequently radioassayed for Sr using an automated gamma spectrometer. The cation exchange capacity was calculated by the number of 

OC 

Sr equivalents retained (adsorbed) per gram of litter. 

Litter was prepared for pH analysis by suspending 1 g litter in 

10 ml distilled water followed by an overnight equilibration. Determinations of pH were made using a Corning Model 110 meter with a combination electrode (Jackson and Watson, 1976). 

Arthropod Diversity Measurement 

Community diversity is generally thought to be directly correlated 

with system stability (Price, 1975; Odum, 1971). To gain some measure 

of stability in Crooked Creek Watershed, all arthropod data was subjected to diversity analysis. 

Diversity of animal or plant taxa within an ecosystem is a measure 

of its heterogenity. As such, it is composed of two elements: the 

richness of taxa (total number) and their equitability (evenness of 

abundance) (Peet, 1974; Price, 1975). A commonly used diversity 

measure is the Shannon-Weaver Index (H') where 

s 

H' - ^ Pi ln P i 

(D 

for p. the proportion of total individuals of taxon j_with £ the 

total number of taxa (Shannon, 1948). Evenness, J', can be estimated 

from 

H' H' J' = H' max TFT (2) 

for S equaling the total number of taxa present (Pielou, 1966; 

Price, 1975). 
P.33 

17 

Arthropod data, classified to family (see Appendix B) were used 

to calculate H', J', and richness for each site. The standard deviation 

of H' was estimated by Hutcheson's approximation method (Hutcheson, 

1970). 

Arthropod Population Density and Biomass 

Food-web interactions among litter-dwelling arthropods of the 

forest floor are intricate, and investigators studying this community 

have made simplifications of the complex processes involved in littersystem function (Szabo, 1974). One often-used simplification is the 

segregation of organisms according to their feeding habits, or trophic 

levels. In a previous study of arthropods occupying the mesic deciduous 

137 forest floor, Cs-tagged litter was successfully used to delineate 

four trophic levels including littergrazers, fungivores, detritivores, 

and predators (McBrayer and Reichle, 1971). These 4 categories, with 

the addition of an omnivore level, were used in segregating Crooked 

Creek Watershed arthropods following taxonomic classification and 

enumeration (Appendix A and B). Omnivores are scavengers and include 

organisms that feed upon plant and animal material that has not yet 

undergone chemical or physical change through decomposition (Hanson, 

1962; Price, 1975). Altered organic material (detritus) serves as an 

energy base for the group classified as detritivores (Odum, 1971; 

McBrayer e_t aj_., 1974). In the present study, determinations of food 

preference within each life stage and taxon were made by consulting 

reference works that incorporated direct observation, gut analysis, and 

radionuclide tracer analysis as methods of studying trophic relationships. Documentation included Borror and De Long, 1964; Borror and 
n 

18 

White, 1970; Cornstock, 1940; Chu, 1949; Hoff, 1949, Jaques, 1951; 

Kaston, 1972; Levi e_t al_., 1968; McBrayer and Reichle, 1971; McBrayer 

et_ aj_., 1974; Peterson, 1956; Price, 1975; Ross, 1965; and Szabo, 1974). 

Two additional categories were created to organize groups for which 

no feeding preference could be found in the literature ("unknown") or 

no morphological development occurred on the forest floor ("accidentals") 

This latter class was not incorporated into any data analysis procedures 

and included insects that were either foliage, seed, stem, or bole 

feeders from the canopy or root feeders from the soil. The occurrence 

of a forest fire in 1969 (Wright, 1974) disrupted the litter arthropod 

community at 2 sites on the N transect, and data from this transect were 

deleted from the study. 

Statistical Procedures 

Litter mass, heavy metal concentrations, and heavy metal pools 

were analyzed as a 4x3x4x2 factorial analysis of variance (ANOVA) replicated 4 times. Experimental classes included 4 seasons, 3 transects, 

4 distances, and 2 horizons. Values from the NE transect (see Figs. 7 

to 10) were analyzed separately from the mair design due to the confounding treatment of ore-concentrate dusts blown into CCW from the 

railway. All main effects and interactions were tested for significance (Snedecor and Cochran, 1967). 

Chemical characterization data gathered for the NW transect were 

subjected to a 4x5x2 factorial ANOVA design replicated 3 times. Classes 

for this analysis were 4 seasons, 5 distances (0.4, 0.8, 1.2, 2.0, and 

21.0 km), and 2 horizons. Again, all main effects and interactions 

were tested for significance. 
- ••m-rmrw-r *P"' f '"FTTff r

 ~ 

19 

Mean comparison testing of litter standing crop, ash, heavy metal 

concentrations and heavy metal pools by season and horizon was performed 

using Duncan's New Multiple Range Test (Duncan, 1951; Steel and Torrie, 

1960). 

Prior to regression analysis, arthropod biomass and density and 

litter mass data were transformed by the following normalization function (Natrella, 1963): 

y = In (x + .5) (3) 

Use of this function also has a variance-stabilizing effect, thus 

allowing application of linear regression models to the transformed 

data (Natrella, 1963). Significance testing was accompanied using 

standard formulae (Draper and Smith, 1966; Steel and Torrie, 1960). 
RESULTS AND DISCUSSION 

Crooked Creek Watershed Litter 

Litter Mass 

Values for 01 litter mass on Crooked Creek Watershed ranged from 

2 2 480 g/m to 120 g/m (Fig. 5) and were comparable to the annual litter 

2 

production of 349 g/m /yr found by Rochow (1974) in a central Missouri 

p 

oak-hickory forest, and the Warm Temperate Forest mean of 360 g/m /yr 

derived by Bray and Gorham (1964). As data for all seasons studied 

in 1974 demonstrated trends similar to those in Fig. 5, September was 

2 chosen to illustrate litter mass/m following summer decomposition but 

prior to leaffall. Thus, data from the autumn sampling period should 

demonstrate conservative estimates of both 01 and 02 litter mass. No 

significant differences in 01 mass among the 15 watershed sites were 

detected by Duncan's New Multiple Range Test (Table 2). 

An accumulation of 02 litter (fragmented material no longer recognizable as to species or origin) was evident at sites near the smelter 

complex (W 0.4 km, NW 0.4, N 0.4, NE 0.4) (Fig. 5, Table 3). Maximum 02 

2 

litter mass/m for September occurred at the N and NE 0.4 sites, with 

values of 2980 and 2590 g/m2, respectively (Table 3). The 02 litter 

mass from sites on the NE transect was apparently not affected by the 

same distance-dependent source producing accumulations near the smelter, 

because 02 mass at NE 0.8 and 1.2 are not significantly different from 

that found at the 0.4 km sites on the W, NW, and N transects (Table 3). 

In general, a decline in 02 litter mass occurred as distance from 

the smelter complex increased (Fig. 6). Although this relationship was 

20 
ORNL DWG 76-3399 

(x102) 

3 0 -

25 

* 2 0 

</> 15 

1 ^0 

- V 

FALL 1974 

WEST TRANSECT 

°2 

°1 

V . 

. - i i . ——- 1 >——*-

0 4 0 . 8 12 

DISTANC E (km) 

1.6-2.0 21.0 

'V-

(x102) 

3 0 

<si 2 5 

* 

Q 2 0 

% 15 < 

5 

0 

i 

(»102) 

35 

3 0 

<SJ 

E 2 5 

* 

o 

o. 2 0 

(S, 

< 15 

2 

O 

<D 10 

5 

0 

0 4 0.8 1.2 (.6-2. 0 

DISTANCE (km) 

21.0 

1 1 

NORTHWEST TRANSECT 

i ~ 

^^** l 

I- . 

1 

i 

r*"** 

•—i r 

V 

L.:I^. 

" I 

A, 

0.4 . 0. 8 1.2 

DISTANC E (km) 

1.6-2.0 21.0 

NORTHEAST TRANSECT 

. .1. . . 

1 

.... 

• K < | 

i 

1 

-

\ 

- • • 

._.. 

s 

\ 

. 1 ,, V ' 

i r 1 . 1 

- • -

.. __._ 

0 4 0. 8 1 2 

DISTANCE (km) 

21.0 

Fig. 5. Mean litter mass (g dry wt/m ) of 01 and 02 horizons on Crooked 

Creek Watershed as a function of distance and direction from 

the AMAX smelter for the September, 1974, sampling period (x ± 

1 SE, n=4). 

ro 

:iJ 
M -

Table 2. Seasonal means of 01 litter mass analyzed by Duncan's New Multiple 

followed by the same letter are not significantly different at the 

Steel and Torrie, 1960). 

Range Test. Means 

5% level (Duncan, 1951; 

March 

Site 

(km) 

NE 0.4 

N 0. 4 

NW 2.0 

NW 1.2 

W 0 .8 

W 1.2 

W 1.6 

N 2.0 

W 21.0 

NW 0.4 

NW0.8 

N 1.2 

NE 1.2 

NE 0.8 

W 0.4 

N 0. 8 

1974 (g/m2) 

Mean 

(x IO2) 

11.8 

7.4 

5.4 

5.0 

4.7 

4.6 

4.5 

4.3 

4.2 

4.1 

4.0 

3.5 

3.4 

3.1 

2.5 

2.2 

Duncan 

A 

AB 

AB 

AB 

AB 

AB 

AB 

AB 

AB 

AB 

AB 

AB 

AB 

B 

B 

B 

June 

Site 

(km) 

NE 0.4 

W 0. 8 

N 0. 4 

NW 2.0 

W 1.6 

NW 1.2 

NE 1.2 

NE 0.8 

NW 0.8 

W 0.4 

NW0.4 

N 0. 8 

N 2.0 

W 21.0 

W 1.2 

N 1.2 

1974 (g/m2) 

Mean 

(x IO2) 

11.6 

10.5 

9.2 

9.0 

7.8 

6.8 

5.9 

5.6 

5.4 

5.4 

5.2 

5.1 

4.5 

4.4 

3.8 

3.1 

Duncan 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

September, 

Site 

(km) 

W 1.6 

W 0. 8 

W 0. 4 

NW 1.2 

N 2.0 

N 0.8 

W 1.2 

W 21.0 

W 16.3 

N 0. 4 

NW0.4 

NE 0.4 

NW0.8 

W 10.4 

N 1.2 

NE 0.8 

NE 1.2 

NW 2.0 

Mean 

(x IO2) 

4.8 

3.9 

3.2 

3.1 

2.9 

2.8 

2.7 

2.7 

2.6 

2.5 

2.5 

2.1 

2.0 

2.0 

1.4 

1.4 

1.4 

1.2 

1974 

Duncan 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

January, 

Site 

(km) 

W 0. 4 

NE 0. 8 

W 1.2 

NE 1.2 

W 10.4 

W 1.6 

N 0. 8 

W 0. 8 

NE 0.4 

W 16.3 

N 2.0 

NW 0.8 

W 21.0 

N 0.4 

N 1.2 

NW 1.2 

NW 0.4 

NW 2.0 

Mean 

(x IO2 

6.5 

5.5 

5.2 

5.1 

4.8 

4.6 

4.5 

4.1 

3.8 

3.8 

3.7 

3.5 

3.5 

3.2 

3.2 

3.1 

2.7 

2.5 

1975 

Duncan 

) 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

A 

ro 

m 
Table 3. Seasonal means of 02 litter mass analyzed by Duncan's New Multiple 

followed by the same letter are not significantly different at the 

Steel and Torrie, 1960). 

Range Test. Means 

5% level (Duncan, 1951; 

March 

Site 

(km) 

N 0. 4 

NE0.4 

NW0.8 

NE 0.8 

W 0. 8 

N 0.8 

NE 1.2 

N 1.2 

W 1.6 

NW 0.4 

NW 1.2 

N 2.0 

NW 2.0 

W 1.2 

W 0.4 

W 21.0 

1974 (g/ 

Mean 

(x IO2) 

27.1 

25.0 

21.4 

20.6 

19.9 

19.9 

17.5 

17.3 

17.2 

16.6 

16.0 

14.1 

13.6 

13.6 

13.3 

9.1 

'm2) 

Duncan 

A 

AB 

ABC 

ABC 

ABC 

ABC 

BCD 

BCD 

BCD 

BCD 

CD 

CD 

CD 

CD 

CD 

D 

June 

Site 

(km) 

NE .8 

NE 1.2 

N 0.4 

N 1.2 

N 2.0 

NE 0.4 

NW 0.8 

W 1.2 

W 1.6 

NW 2.0 

W 0.4 

NW 1.2 

W 0.8 

NW0.4 

N 0.8 

W 21.0 

1974 (g/m2) 

Mean 

(x IO2) 

30.5 

22.8 

22.4 

21.6 

20.1 

18.7 

18.2 

18.1 

16.5 

15.6 

14.9 

12.6 

11.4 

11.1 

8.4 

7.2 

Duncan 

A 

B 

B 

B 

BC 

BCD 

BCD 

BCD 

BCDE 

BCDE 

BCDEF 

CDEF 

DEF 

DEF 

EF 

EF 

September, 

Site 

(km) 

N 0.4 

NE 0.4 

NE 1.2 

W 0.4 

NW 1.2 

NE 0.8 

NW 0.4 

N 2.0 

N 1.2 

NW0.8 

N 0.8 

NW 2.0 

W 0.8 

W 16.3 

W 21.0 

W 10.4 

W 1.6 

W 1.2 

Mean 

(x IO2) 

29.8 

25.9 

22.6 

22.2 

21.0 

20.7 

20.4 

19.4 

18.3 

17.9 

17.7 

17.5 

13.1 

12.3 

12.2 

11.8 

10.6 

10.6 

1974 

Duncan 

A 

AB 

AB 

AB 

BC 

BCD 

BCDE 

BCDEF 

BCDEFG 

BCDEFG 

BCDEFG 

BCDEFG 

CDEFGH 

DEFGH 

EFGH 

FGH 

GH 

H 

January, 1975 

Site 

(km) 

NE 0.4 

NE 0.8 

W 0.4 

N 0.4 

NE 1.2 

N 0.8 

NW0.4 

NW0.8 

NW 2.0 

NW 1.2 

W 1.6 

W 1.2 

N 2.0 

N 1.2 

W 0.8 

W 16.3 

W 21.0 

W 10.4 

Mean 

(x IO2) 

43.2 

34.0 

33.0 

28.5 

26.6 

26.6 

24.4 

21.3 

20.8 

20.0 

19.6 

19.0 

18.5 

18.1 

16.0 

12.9 

12.5 

12.4 

Duncan 

A 

B 

B 

BC 

BCD 

BCD 

CDE 

CDEF 

CDEFG 

DEFG 

DEFG 

DEFG 

DEFG 

EFG 

EFGH 

FGH 

FGH 

H 

ro 

co 
~"!T y»rl'*Wpi T 

24 

ORNL DWG. 74-11187A 

SP.iNC '9T« 

3 0

 i ' 02 (NE "OANSECT EiCLUDEDI 

P.40 

v

t-^ . 

,o - -

,i -..4^= 4 =f=^ 

0 6 1.2 K-2. 0 

DISTANCE (•*> 

ORNL DWG. 74-11186A 

0 8 1.2 16-2.0 

DISTANCE (M l 

ORNL DWG. 7411189R 

—v, v 

ran. i97« 

~ ~.'o7 

-Vr1

 \ 

s K_ 

- T ^ •w~ ^ 

~~*~f—-w-4—-IA— 

5 1 j— • i *- f 

0-4 0. 6 1.2 1.6-2.0 

OISMNCC (>•> 

10 « 16 3 21. 0 

3 " 

i 

ORNL DWG. 74-4349A 

: '/I f, V^~1 

S. 

.INTER t»r. 

0, INC T.*NS£CT E«CLUOC0-

S

i 

-H——•» - ==1r 

VV.-?-V>-; 

-i~Vr^fr-U^. 

-ft ft— 

0 . O f I t I.-1.0 10. 4 I . S tl . 0 

OltT.MCI (»•> 

Fig. 6. Pooled means of litter mass (g dry wt/m ) of 01 and 02 

horizons on Crooked Creek Watershed as a function of distance 

from the AMAX smelter for each sampling period, 1974. Values 

for the NE transect were excluded from computation of the 

means (x + 1 SE, n=12). 
25 

most apparent for the Fall and Winter sampling periods, there was a 

consistent and significant accumulation on all watershed sites (1818+_ 

p 

534 (SE) g/m ) when compared with the primary control sites (1208+328 

(SE) g/m ). No significant differences in mean 02 litter mass existed 

between the primary and secondary control plots (Table 3). Thus, primary 

control values were assumed to represent the unperturbed condition for 

the area. 

For the duration of the study, watershed 01 mass/m (433+29 (SE) 

2 

g/m ) did not vary significantly with time or distance (Fig. 6). In 

2 contrast, control 01 litter mass/m fluctuated about the mean of 350+35 

2 

(SE) g/m (Table 2) , which compared favorably with literature values for 

the forest type under study (Rochow, 1974; Bray and Gorham, 1964). 

However, it should be noted that the mass of 01 litter on Crooked Creek 

Watershed and the control sites were not found to be significantly 

different from one another. 

To determine if litter mass determinations on the watershed had 

been biased by deposition of fugitive particulates from the stack, ash 

determinations were made from subsamples of material collected on the NW 

transect (Table 4). Duncan's analysis indicated no differences in 

litter ash content exist for either litter horizon. In addition, the 

range of ash values (5.3-19.1% for 01 and 20.8-62.5% for 02) compared 

favorably with those of other deciduous forest studies (Reiners and 

Reiners, 1970; McBrayer e_t aj_., 1974; Henderson, 1971). 

Litter Heavy Metal Content 

The highest concentrations of all four elements occurred in 02 

material, where heavy metal values are 1.5 to 2 times greater than 
26 

Table 4. Seasonal Mean ash content (% dry wt) of Crooked Creek 

Watershed litter. One standard error in parentheses 

(n=3). The NW transect was chosen as representative 

of the watershed. 

SPRING SUMMER FALL WINTER 

Site Horizon 

(km) 

Mean 

Ash Content 

Mean 

Ash Content 

Mean 

Ash Content 

Mean 

Ash Content 

NW 0.4 01 

02 

15.6 

58.6 

3.2) 

4.8) 

19.1 

43.9 

3.2] 

4.5: 

14.0 (3.9) 

35.7 (3.3) 

9.1 

32.0 

0.7) 

6.6) 

NW 0.8 01 

02 

5.6 

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0.1) 

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m 
27 

those found in 01 litter (Watson, 1976) (Figs. 7-10). Such accumulation in litter and humus is thought to be governed by passive exchange 

between heavy metal ions occurring in precipitation and foliage leachate 

and the macronutrient ions normally bound to negatively charged organic 

groups (Ruhling and Tyler, 1973; Tyler, 1972). Excepting NE transect 

results, Crooked Creek Watershed lead content of 02 litter can be segregated according to distance: all 0.4 km values were not different from 

each other but were different from those found on the rest of the watershed. Groups of means for the remaining distances graded into one 

another through the controls. Control values did not differ from the 

1.2 km or watershed boundary sites. Similar distributions occurred for 

Zn, Cu, and Cd, although equivalent Cd concentrations were dispersed 

over a larger area (Appendix C). 

As data for all sampling periods illustrated trends similar to 

those in Figs. 7 to 10, September was chosen as a representative season 

to demonstrate conservative estimates of litter lead, zinc, copper, 

and cadmium content. 

Of the 4 metal contaminants found in Crooked Creek Watershed 

litter, Pb was the most abundant (Fig. 7). Zinc, the second most 

abundant heavy metal, was followed by Cu and Cd (Figs. 8-10). Under 

normal operating conditions, particulate stack emissions from the 

AMAX smelter followed the same rank order, i.e., Pb (18510 kg/yr) > 

Zn (1730 kg/yr) > Cu (830 kg/yr) > Cd (50 kg/yr) (Purushothaman, 1974). 

Over 99% of the total heavy-metal concentration found in the entire 

litter horizon at the 0.4 km sites was due to Pb. This percentage 

declined to 93% at the watershed boundary, and was further reduced to. 
28 

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29 

P.45 

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30 

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31 

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Means of litter Cd content (yg/g dry wt) in 01 and 02 horizons 

as a function of distance and direction from the AMAX smelter 

for the September, 1974, sampling period (x + 1 SE, n=4). 
32 

87.3% at the 21.0 km control site (Watson, 1975). The concentration of 

deposited Pb followed the distribution predicted by wind rose patterns 

(Fig. 3) in that the greatest concentrations were found on the NW and N 

transects (103,000 ppm and 76,200 ppm, respectively). Values exceeding 

90,000 ppm were exhibited for the NE transect (Fig. 7) , but were a 

result of fugitive dust deposition from the railway line source. 

With the exception of the NE transect, a steady logarithmic decrease 

in concentration with distance from the smelter complex was apparent for 

all metals and compass directions (Figs. 7-10). These findings were 

consistent with those of other sampling programs measuring heavy metal 

deposition with distance from an area source (Roberts, et al_., 1974; 

Ruhling and Tyler, 1973), and were a result of the particle size distribution of particulate stack emissions (Bondietti e_t a]_., 1975). 

Storage, loading and transport of Pb, Zn, and Cu concentrate from 

the C0MINC0 milling process have produced large quantities of metal-rich 

dusts that are often blown directly into the watershed. Consideration 

of these fugitive sources is necessary to properly interpret results for 

the NE transect displayed in Figs. 7 to 10. Deposition from secondary 

sources was especially apparent in the case of copper (Fig. 9). A 

steady increase in Cu content of 02 litter occurred with increasing 

distance from the stack, and can be attributed to the storage of uneconomical ly recoverable Cu concentrate (4%) in an open bin 20 yards from the 

NE 0.8 km study plot. As a result of the confounding effect of secondary sources on these data, these values were not included in figures of 

seasonal pooled values and were analyzed separately. 

When distance-pooled means of litter Pb, Zn, Cu, and Cd content 

are compared, differences in individual metal concentrations of the 
—T.-K-7W — TMn"jy " • • --T»fTf33 

P.49 

two litter horizons at each distance increment are not statistically 

different from one another (Fig. 11, Appendix D). Means of total litter 

(both horizons) heavy metals at 0.4 km differed from all others on the 

watershed at the 0.1% level; the 0.8 km values differed from those at 1.2 

and 1.6-2.0 km at the 1% level; and 1.2 km values did not differ from 

those at the watershed boundary. This gradient was common for all 4 

metals. 

Least squares multiple linear regression procedures were used to 

further evaluate the relationship between 02 litter mass and litter 

heavy metal concentrations. The empirically derived regression model 

included effects due to season, direction and distance from the AMAX 

smelter, litter heavy metal concentrations, and all interactions due 

to multiplicative effects. 

The model was as follows: 

In (Y + .5) = 6Q + 01x] + B2 x2

 + 63X3 + 84x4 + 85X5 + 6gXg + 

6 7X 7 + e 12x lx 2 + B13xlx3 + 6 23X 2X 3 + 611X1X1 + 

3 22X 2X 2 + B33X3X3 + 3 45X 4X 5 + 6 46X 4X 6 + e47x4x7 + 

6 56X 5X 6 + e 57x 5x 7 + e67x6X7 + e44x4x4 + B55X5X5 + • 

J66X6X6 + 3 7 7X 7X 7 + e (4) 

*1 

Xo = 

X, = 

XJ, = 

where x, = season 

direction (transect) 

distance 

Pb concentration of 02 litter 

Zn concentration of 02 litter 

Cu concentration of 02 litter 

Cd concentration of 02 litter 

litter mass 

X-, = 

Y = 
34 

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JL Oj.l07.9p i gm 

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DISTANCE (»•) 

Fig. 11. Pooled means of litter Pb, Zn, Cu, and Cd concentrations (yg/g 

dry wt) as a function of distance from the AMAX smelter for 

September, 1974. Values for the NE transect were excluded 

from computation of these means (x + 1 SE, n=12). 

'.'Wi-llJ-JM'l'i.JL. 
P.51 

35 

Use of the 23-variable model accounted for 37.1% of the variation 

observed within the data. The resulting regression and correlation 

statistics are given in Tables 5 and 6. 

Application of the backward elimination procedure at P = 0.25, the 

significance level for entry, reduced the effective variables to 10; 

which accounted for 35.8% of the total data variability explained by the 

model (Draper and Smith, 1966). The resulting regression statistics 

are given in Table 7. 

Significant (P<.01), positive correlation coefficients were 

obtained for the first-order variables of season, litter Zn, Cu and Cd 

concentrations, and the multiplicative interactions of litter Pb x Cd, 

Zn x Cu, and Pb x Cu concentrations (Table 6). Thus, high levels of 

heavy metals in the 02 litter occurred simultaneously with large values 

of litter mass. The observed effects of accumulated 02 litter were not 

due to any single factor, but appeared to be interactions among a complex 

of variables. 

Because numerous heavy metal sources existed in the New Lead Belt 

area (fugitive source dusts, other mines and smelters) (Wixson et al., 

1972; Wixson, 1974), the validity of using selected off-watershed sites 

as controls was tested. Comparisons of litter and Al soil horizon heavy 

metal values were made between Crooked Creek Watershed and Walker Branch 

Watershed, a relatively undisturbed deciduous forest study area on the 

Oak Ridge National Laboratory Reservation, Oak Ridge, Tennessee. Analytical procedures similar to those used in the present study have been 

used to derive Pb, Zn, and Cd content of chestnut oak (Quercus prinus 

L.) litter and the Al soil horizon (Jackson, 1976; Van Hook et al., 

1976) (see Table 8) . When these determinations were compared to those 

iMrJiiea.LjtJW8wwwwpww 
P.52 

36 

Table 5. Multiple linear regression statistics for Crooked Creek 

Watershed 02 litter mass (transformed by Eqn. 3) (n = 174, 

23,150 = 3.838, R2 = .370) (g/m2) 

Independent Variable 6n 

8.021 

0 

0 

0 

407 

723 

335 

+ 

+ 

+ 

+ 

+ 

SE 

0. 

0. 

0. 

1. 

379 

164 

917 

218 

Intercept 

Season 

Direction 

Distance 

Litter Pb Concentration 

Litter Zn Concentration 

Litter Cu Concentration 

Litter Cd Concentration 

Season x Direction Crossproduct 

Season x Distance Crossproduct 

Direction x Distance Crossproduct 

Season x Season Crossproduct 

Direction x Direction Crossproduct 

Distance x Distance Crossproduct 

Litter Pb x Zn Concentration 

Crossproduct 

Litter Pb x Cu Concentration 

Crossproduct 

Litter Pb x Cd Concentration 

Crossproduct 

Litter Zn x Cu Concentration 

Crossproduct 

Litter Zn x Cd Concentration 

Crossproduct 

Litter Cu x Cd Concentration 

Crossproduct 

Litter Pb x Pb Concentration 

Crossproduct 

Litter Cu x Cu Concentration 

Crossproduct 

-2.78xl0'6 + 9.5xl0"6 

4.70xl0~4 + 4.46x10"4 

-3.51xl0"4 + 3.42xlO"4 

-0.002 + 0.006 

0.129 + 0.187 

-0.089 + 0.210 

7.383 +6.706 

0.099 + 0.0319 

-3.255 + 3.340 

-4.079 + 3.621 

-1.845xl0"9 + 1.120xl0"8 

-3.468xl0"9 + 2.635xl0"9 

1.800xl0"7 + 1.400xl0"7 

-2.400xl0~7 + 3.800xl0"7 

-6.000X10*8 + 5.8xl0"6 

1.190xl0'6 + 4.220xl0"6 

-1.219xl0'10 + 5.022xl0-11 

1.600x10"7 + 1.4xl0"7 
T\ 

Table 5 (continued) 

37 

Independent Variable gn + SE 

Litter Cd x Cd Concentration 

Crossproduct 

Litter Zn x Zn Concentration 

Crossproduct 

-3.794xl0'5 + 5.901xl0"5 

9.000xl0"8 + 2.900xl0"7 
38 

Table 6. Correlation matrix resulting from multiple linear regression 

analysis of Crooked Creek Watershed 02 litter mass (g/m2, 

transformed by Eqn. 3) (n = 174, F23J50 = 3.838, R2 = .370). 

Values in parentheses are significance levels. 

••"n 

Xl *2 X4 *5 

Y 

X

l 

x2 

x3 

1 .196 .376 

(.01) (.0001) 

1 .002 

(.979) 

1 

.318 

(.0001) 

.005 

(.949) 

.955 

(.0001) 

1 

.222 

(.0033) 

.002 

(.978) 

.556 

(.0001) 

.585 

(.0001) 

.325 

(.0001) 

-.011 

(.882) 

.852 

(.0001) 

.768 

(.0001) 

.289 

(.0001) 

.004 

(.955) 

.847 

(.0001) 

.727 

(.0001) 

1 .692 .394 

(.0001) (.0001) 

1 .893 

(.0001) 

1 

.352 

(.0001) 

.033 

(.669) 

.646 

(.0001) 

.640 

(.0001) 

.902 

(.0001) 

.777 

(.0001) 

.494 

(.0001) 

1 
39 

Table 7. Multiple linear regression statistics for Crooked Creek 

Watershed 02 litter mass (g/m2, transformed by Eqn. 3) 

and independent variables selected by the backward 

elimination procedure at P = 0.25 (n = 174, F,. ,CQ = 

6.344, R2 = 0.358).

 ,4'159 

P.55 

1 

Independent Variable Bn 1 SE 

Intercept 

Season 

Litter Zn Concentration 

Litter Cu Concentration 

Litter Cd Concentration 

Season x Season Crossproduct 

Litter Pb x Cd Concentration 

Crossproduct 

Litter Zn x Cu Concentration 

Crossproduct 

Litter Pb x Cu Concentration 

Crossproduct 

Litter Cu x Cu Concentration 

Crossproduct 

Litter Pb x Pb Concentration 

Crossproduct 

8.021 +0.379 

-0.442 + 0.157 

5.4xl0"4 + 2.4xl0"4 

-3.0xl0' 4 + 2.2xl0' 4 

-6.2xl0"3 + 3.5xl0"3 

0.101 + 0.031 

1.4xl0'7 + 0.4xl0' 7 

•1.5xl0"7 + 0.7xl0'7 

•3.46xl0"9 + 2.635xl0"9 

1.2xl0'7 + 0.5xl0"7 

-1.219xl0"10 + 5.022xl0-11 
40 

of the CCW controls, there was no significant difference between values 

for Cd and Zn in either litter horizon (Table 8) . Apparently, particulates responsible for the Zn and Cd values found on Crooked Creek Watershed did not occur in significant quantities at 21.0 km west of the 

smelter area. In contrast, lead values at Missouri control sites were 8 

to 17 times greater than the Tennessee values. When soil comparisons 

were made, the Zn content of Walker Branch Watershed soil was greater 

than that of Crooked Creek Watershed soil by a factor of 4. Soil Cd and 

?b content did not differ significantly between the two study areas. 

v,;ssouri control-site Pb concentrations may be due to either the 

presence of particulates different from those responsible for Crooked 

Creek Watershed Pb or the occurrence of a subterranean Pb mineralization 

beneath the tree roots. Metals are known to accumulate in ground water 

around ore-bearing deposits and can be detected by chemical analysis of 

above-ground vegetation. Good correlations between plant and soil Pb 

content over lead mineralizations have been obtained (Cannon, 1960). 

Litter Heavy Metal Pool 

The available heavy-metal pool in Crooked Creek Watershed litter 

was calculated by multiplying measured values of Pb, Zn, Cu, and Cd 

2 

litter content with the corresponding litter mass/m at each site. 

Means of September litter heavy metal pools analyzed by Duncan's New 

Multiple Range Test are given in Tables 9-10. Seasonal variation in 

amplitude occurred, but trends due to distance and direction were 

consistent with those in Tables 9-10. 

Available metal pools in 01 litter exhibited the same distribution 

displayed by 01 litter mass for each sampling period, i.e., no 
41 

Table 8. Comparison of Pb, Zn and Cd concentrations (ppm) in 

Walker Branch Watershed (WBW) and Crooked Creek Watershed (CCW) leaf litter and soils. 

TH 

Site 

WBW1 

CCW2 

(21.0 km 

Horizon 

01 

02 

Al 

01 

1i tter 

litter 

soil 

litter 

site) 02 litter 

Al soil 

Pb 

27. 

51. 

13. 

455. 

398. 

13. 

,0 

.0 

.7 

,0 

.0 

.8 

Zn 

42. 

110. 

21. 

68. 

Ill, 

5. 

.0 

.0 

.7 

.8 

.4 

.0 

Cd 

.42 

.81 

.10 

1.65 

2.57 

.23 

1 Data taken from Van Hook et al_., 1976 (Fullerton soil on 

WBW) <n 11tter -72,n so11 -7T . 

2 

Data taken from present dissertation (September) and 

Jackson, 1976 (n1itte r =16 , nSQi l =1) . 

I 
P.58 

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P.60 

44 

significant change occurred throughout the sampling area (Table 9). 

Despite this lack of significance, it can be seen that pool-size was 

positively related to source proximity. 

The distribution of 02 litter pool values paralleled those of the 

02 litter heavy-metal concentrations (Appendix C) , with source-distance 

the dominant factor in establishing ranks of means (Table 10). The rank 

order of metal-pool sizes also follows the ranking previously established 

for the concentration data, i.e., Pb>Zn>Cu>Cd. Over 95% of the total 

metal pool at the 0.4 km sites was due to Pb occurrence, and declined 

only slightly to 93.2% at the boundary sites. The combination of 

reduced metal deposition and 02 litter mass at the control site produced 

a Pb pool equalling 60.5% of the total. However, no significant differences in pool size existed between the control and watershed boundary 

sites. 

Chemical Characterization of Litter 

Litter Macronutrients 

All macronutrient cation concentrations were significantly depressed 

relative to the control in both 01 and 02 litter out to 0.8 km from the 

stack source (Fig. 12). Two mechanisms are postulated to explain these 

results: 1) increased leaching of cations through the litter caused by 

a decrease in microbial activity and disruption of cation exchange 

processes, and 2) decreased uptake of macronutrients due to root damage 

that resulted in a reduced annual input by litterfall. Both hypotheses 

were substantiated by litter data collected from Crooked Creek Watershed. 

Cation exchange processes in 02 litter were affected by a decrease 

in exchange capacity and an increase in acidity (Table 11). Humus, the 
45 

P.61 

*" 

5 (0 |— 

z 

o 

OfiNL-OWO 75-10*50 ORNL-OWG 75-10952 

LITTER HORIZON — 

* 0 

P^ 

0.4 0.8 1.2 «.6 •AH. 2.0 " 2t 

(CONTROL) 

01 STANCE FROM SMELTER (km) 

0.4 0.8 f.2 1.6 2.0 21 

(CONTROL) 

DISTANCE FROM SMELTER (km) 

ORNL-OWG 75-10954 

2.0 21 

(CONTROL) 

ORNL-OWG 75-10953 

AAr-o 

2.0 21 

(CONTROU 

DISTANCE FROM SMELTER (km) OISTANCE FROM SMELTER (km) 

Fig. 12. Mean macronutrient concentrations of Ca, Mg, K, and P (+ 1 SE, 

n=12) in Crooked Creek Watershed litter as a function of 

distance from the AMAX smelter. Data from Jackson and Watson, 

1976. 
46 

residue of decomposition processes, acts as a cation exchanger and aids 

in the conservation of nutrient cations (Lutz and Chandler, 1946). 

Humus may have a cation exchange capacity as high as 110 meq/100 g and a 

buffered pH of 4-5. As it is comprised of a rich mixture of phenolic 

and carboxylic acid groups, it can react strongly with heavy metals 

(Schnitzer and Khan, 1972). The decrease in exchange capacity found in 

Crooked Creek Watershed litter (Table 11) may have resulted from depletion of the microbial populations responsible for maintenance of humic 

reservoirs. Such a reduction in microbial populations was also indicated 

by a significant decline in litter respiration detected near the smelter 

(Ausmus and Watson, 1975). Increased litter acidity (the addition of 

mobile anions) is also known to encourage cation leaching (McColl, 

1972). The acidic litter found within 0.8 km of the AMAX stack (Table 

11) may have resulted from S02 stack emissions and/or dissolution of 

metal sulfide particulates. 

Measurements of macronutrient levels in fresh summer leaves of 

black and white oak indicated that canopy species on Crooked Creek 

Watershed may be experiencing nutrient depletion due to reduced uptake 

(Table 12). Foliage concentrations of Ca, K and P were significantly 

reduced at the most heavily contaminated site (0.4 km). These results 

are consistent with 01 litter content of macronutrients, with the exception of Mg (Fig. 12). The reason for greater uptake of Mg was not 

established. 

Analysis of macronutrient pools in 02 litter for Ca indicated a 

depression near the smelter (0.4 and 0.8 km) (Fig. 13). This decline 

was produced by the extremely low Ca concentration (Fig. 12) in the 

litter at these sites. No significant difference in macronutrient pools 
P.63 

47 

Table 11. Cation exchange capacity and pH of 02 litter on 

Crooked Creek Watershed (NW transect)'. 

Distance 

(km) 

CEC* 

(meq/100 g) pH' 

0.4 

0.8 

1.2 

2.0 

21 (control) 

21.1* 

19.1* 

34.9 

33.4 

40.3 

4.0* 

4.1* 

5.5 

5.2 

5.5 

•Significantly different from the control at P<.05. 

1, 'Data from Jackson and Watson, 1976. 

"Seasonally pooled values (1974, n=12), 
'«T'TIT'"H^"' 

F^4 

"Tl 

48 

Table 12. Mean macronutrient concentration in oak leaves on Crooked 

Creek,Watershed in relation to distance from the smelter 

(n=6)l. 

Distance 

(km) 

0.4 

0.8 

1.2 

2.0 

21.0 (con trol) 

Ca 

7,615* 

9,517* 

11,569 

10,350 

13,016 

Mg 

1,609 

1,448 

1,663 

1,767 

1,504 

K 

ug/g 

5,950* 

7,805 

9,362 

6,572 

8,090 

P 

748* 

931 

1,173 

977 

1,043 

•Indicates significantly different from the control at the 5% level 

Data from Jackson and Watson, 1976. 
49 

for Mg and K was found between the 0.4 and 0.8 km sites and the control. 

This apparent paradox was explained by a combination of low macronutrient 

concentrations (Fig. 12) and high biomass accumulation (Table 3, Fig. 

6 ). Biomass accumulation alone accounted for the increase in all macronutrient pools between 1.2 and 2.0 km (Fig. 13). 

The P pool in 02 litter was not depressed from that of the control 

(Fig. 13). However, a significant depression existed for 01 litter 

(Fig. 13). Phosphorus does not behave as divalent macronutrient cations, 

for it may become bound in organic material and made unavailable for 

root uptake. This binding could account for the accumulation of P in 02 

litter. With less P available for root uptake, incorporation into new 

tissue would be decreased. The net result would be a substantial drop 

in 01 litter P content. 

A decline of all macronutrient pools in 01 litter was observed to 

0.8 km from the stack (Table 13). This depression was governed by a 

decrease in macronutrient concentrations in litter near the smelter, and 

not by litter biomass. No significant differences of macronutrient pool 

values existed between the 1.2 and 2.0 km sites when compared to the 

control. This was evidence that macronutrient uptake had not been 

significantly affected further than 0.8 km from the smelter stack. 

However, macronutrient accumulation in 02 litter pools was indicative 

that uptake may be affected in the future. Analysis of variance indicated a highly significant interaction between macronutrient pools in 

01 and 02 litter. The significance of this interaction is that the 

composition of 02 litter was drastically altered from normal within 0.8 

km from the stack. Due to incomplete decomposition, the bulk of 02 

biomass was a heterogeneous mixture of coarsely to finely fragmented 
1 

30.0 

20.0 

E 

10.0 

50 

ORNL-OWG 75-1095 * 

i r^ n 

T LITTER HORIZON 

* 

I -V-1 

0.4 0.8 1.2 1.6 2.0 21 

(CONTROL) 

OISTANCE FROM SMELTER (km) 

2.0 

< 

o '.0 

2 

i- r 

ORNL-OWG 75-10958 

LITTER HORIZON 

01 

- • %"* 

0.4 0.8 1.2 1.6 2.0 2< 

(CONTROL) 

DISTANCE FROM SMELTER (km) 

ORNL-OWG 75-10955 

0.4 0.8 1.2 I.6 2.0 21 

(CONTROL) 

DISTANCE FROM SMELTER (km) 

j= «.o LITTER (g/ 

z 

_ l o 

2 0.5 

a. 

0 

1 

1 

I T 

i 

^,-i-

» F ' 

! 1 

ORNL-OWG 73-10951 

M. 

LITTER HORIZON _ 

-

0 2 ^ 

*£% ""* 

T 

— 

_ _ oi ~ 

T7/---E 1 

! • tr0.4 0.8 1.2 1.6 2.0 21 

(CONTROL' 

OISTANCE FROM SMELTER (km) 

Fig. 13. Mean macronutrient pool sizes of Ca, Mg, K, and P (+ 1 SE, n=12) 

in Crooked Creek Watershed litter as a function of distance 

from the AMAX smelter. Data from Jackson and Watson, 1976. 

nmpa»» 
51 

Table 13. Macronutrient pools of 02 litter on Crooked Creek 

Watershed (NW transect)^. 

Ca pool' 

(g/m2) 

Mg pool' 

(g/m2) 

K pool2 

(g/m2) 

•Significantly different from control at P<.05. 

Data from Jackson and Watson, 1976. 

P pool 

(g/m2) 

6.5* 

10.9* 

22.9 

23.5 

18.5 

0.98 

1.35 

1.64* 

1.90* 

1.09 

0.83 

1.31* 

1.38* 

1.90* 

0.96 

0.92 

0.15* 

0.25* 

1.08 

0.80 

1 

'Seasonally pooled values (1974, n=12). 
52 

leaves and twigs with a small amount of humus mixed in. Thus, the 

nutrient content of 02 litter in this area was similar to that of 01 

Arthropods 

Population Density and Biomass 

Regression analysis of arthropod density and biomass data collected 

from the 01 litter horizon disclosed the occurrence of considerable 

variation that could not be explained by any measured variable. The 

coefficient of variation (c.v.=100 x s/x; Snedecor and Cochran, 1967) 

exceeded 330%. It seems reasonable to assume that physical factors, 

such as temperature or relative humidity, would be primary controlling 

agents in the arthropod occupancy of the 01 litter horizon, for it is 

known that temperature and moisture regimes are responsible for vertical 

migration within the soil-litter medium (Dowdy, 1944, 1947, and 1951). 

Regardless of the reason, no measure of interactions between arthropod 

activity and litter mass or heavy metal content could be discerned in 

the 01 horizon data from this study. Therefore, only data from the 02 

horizon were analyzed (c.v. = 67.2%). 

The effects of season or wind direction were not sufficient to 

explain variation in either total arthropod population biomass and 

density or population biomass and densities of individual trophic 

levels. Distance from the smelter, however, was a highly significant 

(P<.005) source of variation for predator, detritivore, fungivore, 

and total arthropod biomass and density in the 02 litter horizon (see 

Tables 14, 15 and 16). 

Replicate effects were insignificant (P<.05) sources of variation 

in the analysis of variance of both total and trophic level density 
' TTTT - "" TITT nl 

53 

Table 14. Seasonal mean arthropod biomass (mg dry wt/m2) in the litter 

horizon of Crooked Creek Watershed. One standard error in 

parentheses (n=4). 

SPRING SUMMER FALL WINTER 

Site 

W 0,4 

W 0.8 

W 1.2 

W 1.6 

NW 0.4 

NW 0.8 

NW 1.2 

NW 2.0 

NE 0.4 

NE 0.8 

NE 1.2 

km 

km 

km 

km 

km 

km 

km 

km 

km 

km 

km 

W 21.0 km 

(Control) 

Mean Biomass 

5.7* ( 

34.5* ( 

82.9 ( 

167.1 ( 

2.6* 

55.6 

66.0 

573.0 

11.3* 

23.9* 

110.2 

187.8 

4.0) 

11.4) 

33.1) 

70.9) 

0.9) 

30.3) 

r14.2) 

(10.2) 

( 5.7) 

( 6.0) 

(60.1) 

(70.2) 

Mean Biomass 

93.5 ( 

25.4 ( 

122.8 ( 

109.5 ( 

4.0* 1 

20.0* 

28.9 

195.7 

21.3 

15.5* 

56.5 

61.5 

54.4) 

4.4) 

70.1) 

48.8) 

2.3) 

1.9) 

[ 6.1) 

(20.9) 

( 7.7) 

( 5.0) 

(17.6) 

(22.1) 

Mean Biomass 

11.6* ( 

20.7* ( 

54.5 ( 

190.7 

9.9* 

121.6 

88.8 

96.9 

4.7* 

73.7 

45.1 

137.3 

3.3) 

9. 7) 

17.6) 

130.4) 

4.2) 

' 65.1) 

( 50.4) 

( 61.3) 

( i.o) 

( 55.4) 

( 22.2) 

( 46.3) 

Mean Biomass 

21.3 

30.4 

108.0 

19.4* 

3.2* 

26.7 

33.8 

140.9 

80.6 

25.0* 

29.8 

63.9 

(14.8) 

( 10.2) 

(63.3) 

( 6.7) 

( 1.5) 

(13.8) 

( 9.2) 

(54.3) 

(55.8) 

( 6.8) 

(20.6) 

(17.6) 

•Significantly reduced from the control (P<.10). 
54 

Table 15. Seasonal mean arthropod density (no/m2) in the litter O2 

horizon of Crooked Creek Watershed. One standard error 

in parentheses (n=4). 

P.70 

SPRING SUMMER FALL WINTER 

Site Mean Density Mean Density Mean Density Mean Density 

w 

w 

w 

w 

NW 

NW 

NW 

NW 

NE 

NE 

NE 

0.4 km 

0.8 km 

1.2 km 

1.6 km 

0.4 km 

0.8 km 

1.2 km 

2.0 km 

0.4 km 

0.8 km 

1.2 km 

W 21.0 km 

(Control) 

55.0* ( 

280.0* ( 

106.0 

1917.5 ( 

12.5* 

135.0 

452.5 

1137.5 

75.0* 

127.5* 

132.5* 

1217.5 

26.6) 

100.4) 

558.1) 

1175.1) 

7.5) 

' 83.0) 

196.0) 

' 599.5) 

50.7) 

' 87.7) 

[ 88.5) 

( 462.8) 

165.0* ( 

212.5 ( 

447.5 

257.5 

27.5 

130.0 

537.5 

1942.5 

127.5 

110.0 

252.5 

507.5 

129.4) 

70.9) 

230.8) 

121.5) 

24.3) 

' 58.7) 

207.0) 

727.9) 

' 81.8) 

[ 52.3) 

[ 88.9) 

(317.9) 

110.0 ( 

123.0 ( 

198.0 

885.0 

75.0 

160.0 

263.0 

308.0 

43.0 

90.0 

70.0* 

358.0 

46.0) 

44.0) 

'104.0) 

'326.0) 

' 36.0) 

[ 77.0) 

r145.0) 

[205.0) 

( 24.0) 

( 31.0) 

( 32.0) 

(197.0) 

50.0 ( 

295.0 ( 

375.0 ( 

420.0 ( 

12.5* 

97.5 

270.0 

500.0 

512.5 

157.5 

177.5 

373.0 

21.2) 

138.8) 

225.9) 

176.1) 

7.5) 

47.1) 

128.6) 

'250.3) 

r479.0) 

' 67.9) 

r138.8) 

(175.0) 

•Significantly reduced from the control (POO) . 
P.71 

55 

Table 16. Mean annual Crooked Creek Watershed 02 litter arthropod 

predator, detritivore and fungivore biomass (mg dry wt/m2) 

and density (no/m2). Seasons have been pooled as replicates. 

Values in parentheses are 1 standard error (n=16). 

Biomass (mg/m2) Density (no/m2) 

Site Predator 

(km) 

W 0.4 

W 0.8 

W 1.2 

W 1.6 

NW 0.4 

NW 0.8 

NW 1.2 

NW 2.0 

NE 0.4 

NE 0.8 

NE 1.2 

W 21.0 

(Control) 

6.1^ 

3.6) 

12.1 

2.5) 

15.0 

5.0) 

11.2 

2.9) 

2.1^ 

.4) 

6.8^ 

3.6) 

14.0 

4.0) 

87.6 

41.5) 

5.7^ 

2.4) 

8.53 

2.1) 

17.4 

' 8.4) 

17.3 

' 5.4) 

Detritivore Fungivore 

22.1* 

(13.9) ( 

6.3* 

(1.2) ( 

33.0 

(13.6) ( 

42.4 

(19.6) ( 

2.3* 

( 2.1) 

16.6* 

( 4.5) 

12.6* 

( 2.9) 

92.6 

(40.4) 

18.5* 

(15.4) 

20.4 

(14.9) 

27.6 

(17.7) 

61.1 

(20.4) 

1.2* 

0.3) 

2.7* 

1.4) 

15.1 

7.3) 

13.3 

6.5) 

0.8* 

0.3) 

2.4* 

0.4) 

5.6 

3.2) 

16.1 

'12.0) 

3.1* 

0.8) 

1.1* 

' 0.3) 

2.6* 

22.1 

(10.4) 

Predator 

19.0* 

( 5.5) 

31.9* 

( 7.5) 

76.3 

(22.0) 

72.5 

(20.6) 

10.6* 

( 1-9) 

30.0* 

( 8.9) 

71.9 

(38.9) 

110.6 

(19.7) 

21.9* 

( 2.8) 

44.4* 

( 6.6) 

45.6* 

(17.3) 

86.9 

(15.1) 

Detritivore Fungivore 

36.9* 

( 15.4) ( 

206.9 

( 58.2) ( 

240.6 

( 93.0) 

550.6 

(300.0) ( 

6.3* 

( 3.8) ( 

36.3* 

( 9.7) ( 

143.8 

( 75.7) 

1001.9 

(429.3) ( 

119.4 

( 94.4) 

79.4* 

( 27.6) 

71.3* 

( 16.1) 

294.4 

( 69.4) 

24.4* 

4.3) 

41.3* 

16.1) 

256.3 

164.3) 

298.1 

145.5) 

18.13* 

11.0) 

60.0* 

13.7) 

129.4 

77.4) 

381.3 

261.0) 

57.5* 

15.1) 

20.0* 

7.1) 

26.9* 

' 6.2) 

511.9 

'243.4) 

•Significantly reduced from the control value (P<.10). 
56 

and biomass. Thus, it was assumed that the 4-replicate design utilized 

for arthropod field-sampling on Crooked Creek Watershed in 1974 was 

sufficient to adequately estimate litter arthropod populations. 

Analysis of variance indicated that neither season, distance, nor 

wind direction had significant effects on omnivore or littergrazer 

density and biomass. This result may be due to the variability in 

occurrence of these trophic groups on Crooked Creek Watershed -- omnivores were found in 75% of the samples and littergrazers occurred in 

only 53%. Members of the other three trophic levels were found in over 

90% of the samples. 

Least squares multiple linear regression procedures were used to 

evaluate the variation found in measurements of CCW total arthropod 

biomass and density (Tables 14 and 15). The empirically derived regression model included effects due to season, direction and distance from 

the AMAX smelter, litter heavy metal concentration; and all interactions 

due to multiplicative effects. The linear model presented as Equation #4 

was also used to evaluate the dependent variables, total arthropod biomass and density. Use of the 23-variable model accounted for 51.2% of 

the variation within the total arthropod biomass, but only 15.2% of 

the total density variation. 

The inability of the model to adequately explain variability within 

the arthropod density data may be due to several factors. First, it is 

highly probable that the relationships between arthropod density and 

the measured independent variables may be explained by a non-linear 

model. Only multiple linear models were evaluated in the present data 

analysis. Secondly, both historical and current temperature-moisture 

regimes are known to be important in determining the distribution of 
P.73 

57 

arthropods at any one point in time (Dowdy, 1944, 1947, 1951; Andrewartha 1961). These factors, for which no records were available, may 

be responsible for a large portion of the unexplained variability in the 

CCW arthropod density measurements. 

Examination of regression statistics from analysis of arthropod 

biomass data revealed that not all 23 variables were necessary to 

account for a major portion of total variation (Tables 17 and 18). 

Subsequent analysis by stepwise, and forward and backward elimination 

regression procedures (Draper and Smith, 1966) indicated that the 

latter method provided the best evaluation of variability within the 

data at P = 0.25 the significance level for entry. 

With the number of effective independent variables reduced to 9, 

50.7% of the total variation can be accounted for (Table 19). Significant (P<.01) negative correlation, coefficients were obtained for the 

first-order variables litter Zn and litter Cd concentrations and the 

multiplicative interactions of litter Pb x Zn, Pb x Cu, Zn x Cu, Zn x 

Cd and Cu x Cd concentrations (Table 18). The second-order variables 

of litter Cu x Cu and Cd x Cd were also negatively correlated (P<.01) 

with arthropod biomass (Table 18). Thus, high levels of heavy metals 

in the litter substrate occurred simultaneously with small arthropod biomass values. Since distance from the AMAX smelter was also significantly correlated with litter heavy metal content (see also Figs. 7-10), 

this heavy metal effect on the arthropod biomass may be responsible for 

the significant distance effect detected by previous ANOVA analysis. 

Interactions between arthropod biomass and litter heavy metal 

content on the Crooked Creek Watershed forest floor were not simple 

one-to-one relationships. Results of the present regression analysis 
58 

• •T- S . » r T , - Tff ^ 1 T • 

Table 17. Multiple linear regression statistics for Crooked Creek 

Watershed 02 litter arthropod biomass (mg/m2, transformed 

by Eqn. 3) (n = 176, F23 152 = 6.931, R2 = 0.512). 

Independent Variable 

Intercept 

Season 

Direction 

Distance 

Litter Pb Concentration 

Litter Zn Concentration 

Litter Cu Concentration 

Litter Cd Concentration 

Season x Direction Crossproduct 

Season x Distance Crossproduct 

Direction x Distance Crossproduct 

Season x Season Crossproduct 

Direction x Direction Crossproduct 

Bp + SE n -

-0.059 + 0.694 

0.240 + 0.357 

4.086 + 1.992 

-10.407 + 2.401 

4.94xl0"6 + 2.056xl0"5 

1.062xl0'3 + 9.649xl0"4 

3.187xl0~4 + 7.262xl0"4 

-0.017 +0.013 

-0.137 + 0.407 

0.755 + 0.457 

-18.296 + 14.536 

-0.025 +0.069 

9.548 + 7.212 

-q 

Distance x Distance Crossproduct 

Litter Pb x Zn Concentration 

Crossproduct 

Litter Pb x Cu Concentration 

Crossproduct 

Litter Pb x Cd Concentration 

Crossproduct 

Litter Zn x Cu Concentration 

Crossproduct 

Litter Zn x Cd Concentration 

Crossproduct 

Litter Cu x Cd Concentration 

Crossproduct 

Litter Pb x Pb Concentration 

Crossproduct 

Litter Cu x Cu Concentration 

Crossproduct 

Litter Cd x Cd Concentration 

Crossproduct 

Litter Zn x Zn Concentration 

Crossproduct 

5.972 + 7.925 

3.0xl0'3 + 2.0xl0"8 

-4.0xl0"8 + 2.0xl0"8 

-1.8xl0"7 + 3.0xl0"7 

8.8xl0"7 + 8.3xl0"7 

-1.718xl0'5 + 1.257xl0"5 

8.87xl0"6 + 8.96xl0"6 

-5.99xl0'12 + 6.25xl0-11 

-4.1xl0"7 + 3.0xl0"7 

2.002xl0'4 + 1.293xl0"4 

-2.9xl0"7 + 6.4xl0"7 

swwgmu'Ji ^'JT 
•T- 'in WY^* ITTTTnTr""" TH 

59 

Table 18. Correlation matrix resulting from multiple linear 

regression analysis of total arthropod biomass 

(mg/m2, transformed by Eqn. 3) found on Crooked 

Creek Watershed (n = 176, F23 , „ = 6.931, R2 = 

0.512). Values in parentheses are significance 

levels. 

Y 

X

l 

Y 

1 

X

l 

-.107 

(.158) 

1 

x2 

-.380 

(.0001) 

0.0 

(1.0) 

X

3 

-.459 

(.0001) 

0.0 

(1.0) 

X

4

 X5 X6 

-.514 -.317 -.205 

(.0001) (.0001) (.006) 

.009 -.003 .011 

(.906) (.965) (.885) 

X

7 

-.476 

(.0001) 

.042 

(.577) 

.954 .551 .845 .842 .637 

(.0001) (.0001) (.0001) (.0001) (.0001) 

1 .577 .759 .720 .628 

(.0001) (.0001) (.0001) (.0001) 

1 .695 .398 .902 

(.0001) (.0001) (.0001) 

1 .894 .780 

(.0001) (.0001) 

1 .498 

(.0001) 

1 
60 

Table 19. Multiple linear regression statistics for Crooked Creek 

Watershed 02 litter arthropod biomass (mg/m2, transformed 

by Eqn. 3) and independent variables selected by the backward elimination procedure at P = 0.25 (n = 176, F,. ,c, = 

10.178, R2 = 0.507).

 14'161 

Independent Variable Bp + SE 

n -

P.76 

T1 

Intercept 

02 Litter Zn Concentration 

02 Litter Cd Concentration 

02 Litter Pb x Zn Concentration 

Crossproduct 

02 Litter Pb x Cu Concentration 

Crossproduct 

02 Litter Zn x Cu Concentration 

Crossproduct 

02 Litter Zn x Cd Concentration 

Crossproduct 

02 Litter Cu x Cd Concentration 

Crossproduct 

02 Litter Cu x Cu Concentration 

Crossproduct 

02 Litter Cd x Cd Concentration 

Crossproduct 

-0.059 +0.694 

0.001 + 0.0006 

-0.020 +0.010 

l.OxlO'8 + l.OxlO"8 

3.0xl0"8 + l.OxlO"8 

4.4xl0' 7 + 1.5xl0"7 

18.6xl0'6 + 6.0xl0"6 

10.3xl0"6 + 5.5xl0~6 

•2.5xl0"7 + l.OxlO'7 

15.9xl0"5 + 6.0xl0"5 
P.77 

T II 

61 

indicated that no single factor can be isolated as the primary source of 

variability in watershed arthropod biomass. A complex of variables must 

be considered. However, it was clearly demonstrated that the heavy 

metal content of Crooked Creek Watershed litter was not only strongly 

and negatively correlated with arthropod biomass, but was also responsible for 50% of total data variation. 

Heavy Metals 

Field-collected arthropods were pooled to provide sufficient 

material for heavy metal analysis of each trophic level. Specimens 

categorized by season and replicate, variables known to be insignificant in controlling population density and biomass, were combined 

across both litter horizons. The resulting pooled samples were composed of 32 individual samples (4 seasons x 4 replicates x 2 horizons) 

and were assayed for Pb, Zn, Cu, and Cd content. 

] Lead: Previous documentation of arthropod Pb concentrations 

associated with trophic classification indicated that the most elevated 

levels occurred in the detritivore-fungivore groups (Williamson and 

Evans, 1972). Isopods feeding in decaying vegetation on Yorkshire 

roadsides contained 682 ppm dry wt Pb (Williamson and Evans, 1972). 

Littergrazing diplopods and predaceous opilionids and spiders were next 

in order of decreasing lead content, with values of 82, 45, and 23 ppm 

respectively. Other published values for roadway-source Pb in arthropods were lower than those found by Williamson and Evans (Giles et al., 

1973; Institute of Envir. Studies, 1972). 

The Pb content of isopods collected on Yorkshire ditchbanks is 

comparable to that of Crooked Creek Watershed fungivores. Otherwise, 
62 

watershed values exceed all previously published information for 

comparable trophic levels and for the same trophic level at the watershed control site (Table 20). Elevated quantities of Pb were found 

associated with predaceous arthropods collected from heavily Pbcontaminated sites near the smelter (cf Fig. 7) 

Zinc: Zinc is known to be necessary to a number of biologically 

important enzyme reactions both by acting as a nonspecific cofactor 

in controlling the rate of reaction and as a constituent of many 

metalloenzymes (Orten, 1966). Zinc is also necessary for RNA and 

DNA formation (Schroeder, 1974). Thus, this element is a normal 

component of biological systems. However, due to the complete absence 

of comparable data it is not known if the quantities found associated 

with the Crooked Creek Watershed arthropod population (Table 21) are 

different from what would be expected in a non-polluted system. 

Copper: Copper is contained in the arthropod blood protein, 

hemocyanin, and is a normal constituent of all arthropod tissue (Wieser, 

1961; Wigglesworth, 1965). However, since trophic level Cu concentrations found at the 21.0 km control site were significantly less than 

any of those found on the watershed, the elevated levels of Cu associated with Crooked Creek Watershed arthropods are real (Table 22). 

The highest levels of Cu found in the spider, "other predator", 

and omnivore populations occurred at those sites located either closest 

to the smelter or along the NE transect. Exposure to Cu concentrate 

on this transect appeared to produce elevated Cu levels in litter arthropods comparable to those produced by exposure to stack emissions. 

Cadmium: Previous documentation of arthropod Cd concentrations 

include values for grasshoppers collected at varying distances from 
1 

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P.81 

65 

Table 22. Copper concentrations (pg/g dry wt) found associated with 

arthropod trophic levels on Crooked Creek Watershed. 

Specimens from both litter horizons and all seasons and 

all replicates were pooled for chemical analysis (n=32). 

Site 

(km) 

W 0.4 

W 0.8 

W 1.2 

W 1.6 

NW 0.4 

NW 0.8 

NW 1.2 

NW 2.0 

NE 0.4 

NE 0.8 

NE 1.2 

W 21.0 

(control) 

Predator* 

547.8 

138.9 

32.5 

28.1 

320.5 

37.5 

98.0 

59.4 

136.2 

83.3 

169.1 

48.6 

Spider 

197.4 

176.6 

174.1 

129.8 

242.9 

181.5 

72.9 

151.9 

448.7 

626.0 

480.0 

72.9 

TROPHIC 

Detritivore 

155.9 

204.1 

54.9 

13.3 

476.2 

79.2 

512.8 

50.7 

122.0 

163.0 

1189.2 

24.1 

LEVEL 

Fungivore 

200.0 

555.6 

47.6 

75.0 

71.7 

220.0 

140.2 

172.4 

200.0 

137.9 

500.0 

149.3 

Littergrazer 

137.1 

86.4 

42.5 

200.0 

291.3 

72.1 

302.2 

101.5 

63.8 

275.9 

479.5 

109.3 

Omnivore 

156.6 

47.3 

43.5 

28.8 

84.7 

32.8 

27.6 

31.8 

263.2 

795.5 

768.4 

20.4 

*0ther than spiders 
66 

109 

a Zn smelter in Montana and the results of a Cd tagging experiment 

utilizing a grass-cricket (Pteronemobius sp.)-spider (Lycosa sp.) food 

chain (Munshower, 1972; Van Hook and Yates, 1975). Grasshoppers feeding on contaminated vegetation containing 1.8 and 1.0 ppm Cd (2.4 and 

24 km from the smelter source) incorporated whole-body Cd levels of 7.1 

and 1.8 ppm respectively (Munshower, 1972). Omnivorous crickets and 

predaceous spiders in a trace-contaminated system (.069 ppm Cd in 

vegetation) incorporated much lower amounts of Cd (0.042 and 0.030 ppm, 

respectively (Van Hook and Yates, 1975). 

Cadmium values for Crooked Creek Watershed arthropods collected at 

the control site were comparable to those of Munshower's (1972) herbivorous grasshoppers, and ranged from 1.4 ppm for fungivores to 10.2 ppm 

for omnivores (Table 23). The average Cd content of both litter horizons 

at the CCW control site was 5.1 ppm (Appendix C). Cadmium is commonly 

found associated with Zn in geological formations (Schroeder, 1974), and 

it is expected that Cd values in biota collected near a Zn smelter would 

represent a highly contaminated condition. Even though different trophic 

levels were studied at the two sites it was clear that Crooked Creek 

Watershed arthropod Cd values were either comparable to, or exceeded, 

those found near other Cd sources (Table 23). 

Concentration Factors 

The ecological consequences of heavy-metal transport in food 

chains can be partially evaluated by an analysis of concentration 

factor data. A concentration factor (CF.) is defined as the "ratio 

of element level in consumer to elementleyel in food-chain base" 

(Reichle et_ al_., 1970). Elements ingested by the consumer may be 
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68 

diluted (C.F^< 1.0), concentrated (CF. > 1.0), or undergo no change 

(CF. = 1.0) relative to the levels found in the food base. Concentration factors, weighted by the proportion of total biomass provided 

by each litter horizon or trophic level, have been derived for Pb, Zn, 

Cu, and Cd in the CCW litter-arthropod food chain (Tables 24-27). 

Concentration values given in Tables 20-23 were used in the calculations. As an example of Pb concentration factor estimates for the 

litter fauna:litter food base at the W .4 km site, the following 

calculation was performed: 

C F = P[) [PbD] + P F [PbF] + P Q [Pbg] + pL [PbL] 

p01 [Pb 0 1] +p 0 2 [Pb 0 2] 

where 

P D = proportion of total litter fauna biomass provided by 

detritivores = 0.671 

pr = proportion of total litter fauna biomass provided by 

fungivores = 0.045 

p = proportion of total litter fauna biomass provided by 

" omnivores = 0.277 

p. = proportion of total litter fauna biomass provided by 

littergrazers = 0.006 

p m = proportion of total litter mass provided by 01 litter = 

Ul 0.180 

p n 9 = proportion of total litter mass provided by 02 litter = 

U6 0.820 

[PbD] = concentration of Pb (yg/g dry wt) found associated with 

arthropod detritivores = 1000.0 

[PbF] = concentration of Pb (ug/g dry wt) found associated with 

arthropod fungivores = 388.9 

[Pb ] = concentration of Pb (ug/g dry wt) found associated with 

0 arthropod omnivores = 2857.1 
. TM -.- ^ lrlrw ^^. mwnr -

69 

Table 24. Weighted concentration factors calculated for Pb transport 

in the Crooked Creek watersned litter-arthropod food chain. 

if V i 

l* 

i 

-

Site 1 

(km) 

W 

W 

W 

W 

NW 

NW 

NW 

NW 

NE 

NE 

NE 

0.4 

0.8 

1.2 

1.6 

0.4 

0.8 

1.2 

2.0 

0.4 

0.8 

1.2 

W 21.0 

(control) 

.itter Fauna 

Litter 

0.02 

0.04 

0.12 

0.06 

0.06 

0.02 

0.04 

0.05 

0.02 

0.03 

0.28 

0.10 

^CENTRA " 

Spiders 

Litter Fauna 

1.12 

0.56 

0.19 

1.95 

0.81 

0.49 

0.77 

0.37 

3.66 

1.76 

0.01 

0.42 

TION FACTORS^ 

Predators* 

Litter Fauna 

19.13 

4.20 

0.52 

0.43 

3.44 

0.28 

0.76 

0.53 

1.39 

0.68 

0.13 

0.65 

' |.i3 

All Predators 

Litter Fauna 

10.67 

2.49 

0.42 

1.17 

2.75 

0.31 

0.76 

0.51 

2.39 

1.23 

0.10 

0.60 

*0ther than spiders 
- • *r ~T>"H^rT "r «~rF»rif''" 

P.86 

70 

Table 25. Weighted concentration factors calculated for Zn transport 

in the Crooked Creek Watershed litter-arthropod food chain. 

Site L 

(km) 

W 0.4 

W 0.8 

W 1.2 

W 1.6 

NW 0.4 

NW 0.8 

NW 1.2 

NW 2.0 

NE 0.4 

NE 0.8 

NE 1.2 

W 21.0 

(control) 

itter Fauna 

Litter 

0.52 

0.91 

0.76 

0.95 

0.43 

0.38 

0.83 

1.80 

0.12 

0.17 

0.20 

2.09 

CONCENTRATION FACTORS 

Spiders 

Litter Fauna 

0.71 

1.55 

1.99 

1.83 

0.98 

2.15 

1.18 

0.80 

2.90 

2.02 

1.51 

2.57 

Predators* 

Litter Fauna 

0.93 

1.34 

1.63 

1.25 

0.43 

0.85 

1.76 

0.79 

1.06 

1.13 

0.70 

2.69 

All Predators 

Litter Fauna 

0.83 

1.44 

1.74 

1.53 

0.57 

1.03 

1.71 

0.79 

1.87 

1.58 

0.90 

2.66 

*0ther than spiders 
71 

Table 26. Weighted concentration factors calculated for Cu transport 

in the Crooked Creek Watershed litter-arthropod food chain. 

• *r"1 

Site L 

(km) 

W 0.4 

W 0.8 

W 1.2 

W 1.6 

NW 0.4 

NW 0.8 

NW 1.2 

NW 2.0 

NE 0.4 

NE 0.8 

NE 1.2 

W 21.0 

(control) 

.itter Fauna 

Litter 

0.17 

0.92 

0.34 

0.28 

0.23 

0.15 

1.10 

0.61 

0.09 

0.08 

0.22 

2.06 

CONCENTRATION FACTORS 

Spiders 

Litter Fauna 

0.59 

0.37 

1.07 

1.96 

0.22 

0.40 

0.03 

0.32 

1.42 

1.17 

0.12 

0.27 

Predators* 

Litter Fauna 

1.84 

0.32 

0.47 

0.44 

0.83 

0.51 

0.46 

0.72 

0.55 

0.15 

0.13 

0.68 

All 

Lit 

Predators 

ter Fauna 

1.25 

0.34 

0.65 

1.18 

0.67 

0.49 

0.42 

0.66 

0.93 

0.67 

0.13 

0.59 

*0ther than spiders 
P.88 

Tl 

72 

Table 27. Weighted concentration factors calculated for Cd transport 

in the Crooked Creek Watershed litter-arthropod food chain. 

Site L 

(km) 

W 0.4 

W 0.8 

W 1.2 

W 1.6 

NW 0.4 

NW 0.8 

NW 1.2 

NW 2.0 

NE 0.4 

NE 0.8 

NE 1.2 

W 21.0 

(control) 

itter Fauna 

Litter 

0.65 

0.22 

0.51 

0.39 

0.38 

0.33 

0.26 

0.50 

0.10 

0.10 

0.34 

0.64 

CONCENTRATION FACTORS 

Spiders 

Litter Fauna 

0.51 

5.35 

1.44 

2.74 

0.52 

0.32 

0.10 

0.57 

1.12 

3.77 

0.65 

0.27 

Predators* 

Litter Fauna 

0.85 

1.83 

0.64 

0.84 

0.50 

0.38 

1.99 

0.99 

0.51 

0.79 

0.29 

1.15 

All Predators 

Litter Fauna 

0.69 

3.48 

0.88 

1.77 

0.51 

0.37 

1.82 

0.93 

0.78 

2.31 

0.38 

0.97 

*0ther than spiders 
P.89 

"Til 

73 

[Pb,] = concentration of Pb (ug/g dry wt) found associated with 

arthropod littergrazers = 485.7 

[Pbnl] = concentration of Pb (yg/g dry wt) in 01 litter = 

Ul 38.0x103 

[Pbno] = concentration of Pb (yg/g dry wt) in 02 litter = 

^ 70.3xl03 

C F . = 1482.8 = .02 

64486.0 

Lead:) The concentration of Pb decreased from litter to litter 

fauna on Crooked Creek Watershed (Table 24). A plot of the log of 

food base Pb concentration (range: 430 to 68770 ppm) vs. corresponding 

concentration factor values for litter-feeding fauna (range: 0.02 to 

0.28) illustrated that a mean concentration factor of 0.07 +_ 0.02 (S.E.) 

would be an adequate estimate of Pb transport in the grazing food chain. 

Arthropod predators appeared to be either concentrating or in 

equilibrium with the Pb content of their litter fauna prey. With the 

exception of the elevated "other predator" concentration factor found 

at W 0.4 km, the predator concentration factors ranged between 0.01 to 

4.20. The corresponding variation in prey Pb concentration was from 

43 to 11516 ppm. 

A semilog plot of prey Pb concentration vs. Pb concentration 

factors indicated that a mean concentration factor would be an adequate 

representation of Pb biotransfer from prey to predator. The means are: 

t 0.29 (S.E.) 

= 1.18 + 0.41 (S.E.) 

C -F -spiderPb = 1 -0 1 ±0 -2 9 <S'E-> 

CF. other predator Pb 

C'F'total predator Pb = 1-16 + 0.29 (S.E.) 

These means are conservative in that the one elevated concentration 

factor at the W 0.4 km site has been deleted. 
74 

P.90 

Zinc: Zinc was being accumulated in Crooked Creek Watershed litter 

fauna to a much greater extent than was Pb, although concentration 

(CF>1.0) does not yet appear to be occurring (Table 25). Zinc is 

required by living systems (Orten, 1966; Schroeder, 1974), and the 

concentration factors found for Crooked Creek Watershed arthropods may 

reflect physiological requirements. The largest litter fauna:litter 

concentration factors existed where the smallest litter-Zn values 

occurred - W 1.6 km ([Zn,... ] = 100 ppm). Litter Zn varied from 100 

to 3894 ppm while the litter fauna concentration factor estimations 

varied from 0.12 to 2.09. Plotting of the data as previously discussed 

indicated that a mean of 0.64 +_ 0.15 (S.E.) adequately represented the 

biological transfer of Zn presently occurring in this food chain. 

It is not clear if arthropod predators concentrated or equilibrated 

Zn in relation to their food base. As predator concentration factors 

varied between 0.4 and 2.7, prey Zn varied between 206.8 and 909.1 ppm. 

Mean concentration factors were: 

CF-sp,derZn = 1 -6 0 i°- 2 0 (SE-> 

"•othe r predator *,- 1.08 ± 0.12 (S.E.) 

"•tota l predator ZB • 1.27+ 0.14 (S.E.). 

Copper: Concentration (CF.>1.0) of Cu through the litter fauna: 

litter food chain does not appear to occur on Crooked Creek Watershed 

(Table 26). Copper was being accumulated in litter fauna to a much 

greater extent than was Pb, but this phenomenon may be a result of 

copper's presence in the arthropod circulatory system as hemocyanin 

(Wieser, 1961; Wigglesworth, 1965). As litter copper concentrations 

varied between 27 and 4590 ppm, concentration factor values varied 
75 

P.91 

between 27 and 4590 ppm, concentration factor values varied between 0.8 

and 2.06. The mean Cu litter fauna CF . was 0.38 +_ 0.10 (S.E.). The 

highest litter concentration factor occurred where the smallest litter 

Cu value existed -- W 21.0 km. 

In contrast to results for Pb and Zn, Cu appeared to be diluted by 

food-chain transfer from prey to predator on Crooked Creek Watershed. 

Mean concentration factors were: 

C

-

F

-spiderCu

 = 0

-

7 0 ±°- 1 9 ^ - E

- ) 

CF'other predator Cu = 0 '5 8 ±°- 1 4 <S'E-) 

C'F-total predator Cu = 0 -6 7 ±0 -1 0 ^S.E. ) 

Cadmium: Concentration factors for Crooked Creek Watershed litter 

fauna (Table 27) were comparable to those found for omnivorous crickets 

(Pteronemobius spp., CF . = 0.6) fed on Cd-tagged vegetation ([Cd] = 

0.069 ppm) (Van Hook and Yates, 1975). Cadmium was not concentrated in 

the Crooked Creek Watershed litter-litter fauna food chain, although Cd 

was accumulated to a greater degree than Pb (Table 24). The range of 

predator concentration factors (0.10 to 3.48) included the value calculated for Lycosid spiders preying upon Cd-tagged Pteronemobius (Van 

Hook and Yates, 1975). After 30 days' feeding, Lycosa had accumulated 

70% of the total Cd available in the prey substrate (i.e., CF . = 0.7) 

(Van Hook and Yates, 1975). The only other arthropod food-chain data 

available deal with herbivorous grasshoppers that fed on Cd-contaminated vegetation near a Montana Zn smelter (Munshower, 1972). The 

overall grass-herbivore concentration factor was 1.3. 

Concentration (CF.>1.0) of Cd occurred among the predator populations exposed to prey containing <_ 9 ppm Cd (W 0.8 and 1.6 km; NW 1.2 km; 
-S UPf F >r*irrrvr " Tl 

76 

NE 0.8 km; and W 21.0 km). At prey concentrations exceeding 9 ppm, ail 

predator concentration factors < 1. 

Diversity 

An indicator of biological changes within the Crooked Creek Watershed forest floor community is arthropod diversity. Use of Equations 1 

and 2 and data included in Appendix B produced the diversity, evenness 

and richness indices given in Table 28. Significance testing of Pielou's 

evenness 'J' and the Shannon-Weaver Diversity Index H' pointed out the 

extreme variability within the data, and no consistent trends could be 

observed for these two parameters (Hutcheson, 1970; O'Neill et al., 

1976). However, richness, S, was shown to be a significant indicator of 

heavy metal effects on Crooked Creek Watershed arthropod diversity 

(ANOVA). Values of S (total number of taxa=families), equivalent to H' 

max and necessary for the computation of evenness 'J* (Equation 2) , 

varied significantly with distance, direction and distance x direction 

interaction effects (P<.01). Thus, the richness component of total 

arthropod diversity was shown to be more sensitive to perturbations on 

CCW than either the evenness of abundance component or total arthropod 

diversity. 
""">" "Wy » * T'' 1MJ Ml1

' T^l 

77 

Table 28 

Crooked Creek Watershed litter arthropod diversity indices for each 

site, horizon and season. 

a. Shannon-Weaver Index, H' (calculated by Equation #1). 

b. Pielou's evenness index J' (calculated by Equation #2). 

c. Richness index S (total number of families). 
"yl 

78 

Shannon-Weaver Index H'. 

Site 

(km) 

W 0.4 

W 0.8 

W 1.2 

W 1.6 

NW 0.4 

NW 0.8 

NW 1.2 

NW 2.0 

NE 0.4 

NE 0.8 

NE 1.2 

W 21.0 

(Control) 

Hor 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

March 

1974 

0.693 

2.083 

2.479 

1.708 

1.906 

1.769 

1.359 

1.382 

2.946 

1.557 

2.151 

1.887 

2.212 

1.995 

1.555 

1.378 

1.099 

1.126 

2.020 

2.596* 

2.095 

2.518* 

2.176 

1.625 

June 

1974 

1.192 

2.124 

1.939 

1.768* 

2.193 

2.479 

1.981 

2.367 

2.233 

2.152 

2.568 

2.789 

1.425 

1.917* 

0.999 

1.339* 

2.150 

2.295 

1.818 

2.340 

2.005 

2.372 

1.767 

2.475 

Sept. 

1974 

1.396 

2.143 

1.911 

2.367 

1.939 

2.684 

1.745 

1.809* 

1.790 

1.801 

1.779 

2.790 

1.494 

1.967 

2.797 

2.491 

1.486 

1.747 

1.524 

2.356 

1.988 

2.633 

1.852 

2.316 

Jan. 

1975 

2.119 

2.157 

1.475 

1.167* 

2.055 

1.669 

1.330 

1.031* 

1.228 

1.427 

1.540 

2.204 

1.877 

1.919 

2.261 

2.037 

0.500 

1.117* 

.628 

1.763 

1.733 

2.136 

1.935 

2.060 

*Significantly different from the control at P<.05. 
—r>e •^rmryj'W'' • m 

b. Evenness 'J 

79 

Site 

(km) 

W 0.4 

W 0.8 

W 1.2 

W 1.6 

NW 0.4 

NW 0.8 

NW 1.2 

NW 2.0 

NE 0.4 

NE 0.8 

NE 1.2 

W 21.0 

(Control) 

Hor 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

01 

02 

March 

1974 

1.000 

.838 

.875 

.570 

.743 

.537 

.845 

.419 

1.086 

1.123 

.815 

.697 

.765 

.655 

.511 

.418 

1.585 

.829 

1.038 

.916 

1.076 

.792 

.825 

.499 

June 

1974 

.518 

.722 

.735 

.590 

.855 

.770 

.773 

.745 

.931 

.980 

.907 

.947 

.556 

.677 

.455 

.390 

1.105 

.847 

.790 

.864 

.871 

.757 

.624 

.769 

Sept. 

1974 

.717 

.812 

.769 

.835 

.756 

.882 

.629 

.577 

.861 

.725 

.914 

.890 

.483 

.668 

1.060 

.747 

.764 

.898 

.851 

.870 

.956 

.911 

.772 

.711 

Jan. 

1975 

.853 

.899 

1.064 

.455 

.893 

.567 

1.210 

.350 

1.117 

.887 

.957 

.814 

.903 

.692 

1.029 

.659 

.722 

.413 

.906 

.610 

.967 

.739 

1.080 

.625 
1 

80 

c. Richness 

Site 

(km) W 0.4 W 0.8 W 1.2 W 1.6 NW 0.4 NW 0.8 NW 1.2 NW 2.0 NE 0.4 NE 0.8 NE 1.2 W 21.0 

S. 

Hor 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01 02 

March 

1974 

2 

12 17 20 13 27 

5 

27 

6 

4 

14 15 18 21 21 27 

2 

13 

7 

17 

7 

24 14 26 

June 

1974 10 19 14 20 13 25 15 24 11 

9 

17 19 13 17 

9 

31 

7 

15 10 15 10 23 17 25 

Sept. 

1974 

7 

14 12 17 13 21 16 23 

8 

12 

7 

23 22 19 14 28 

7 

7 

6 

15 

8 

18 11 26 

Jan. 

1975 12 11 

4 

13 10 19 

3 

19 

3 

5 

5 

15 

8 

16 

9 

22 

2 

15 

2 

18 

6 

18 

6 

27 
GENERAL DISCUSSION 

Heavy Metal Effects on Biota 

Measures of biological activity in Crooked Creek Watershed litter 

horizons performed during the present study included litter mass; total 

and trophic level arthropod density and biomass; total arthropod diversity, evenness and richness; and preliminary measurements of litter 

respiration. Additional supportive data were collected by E. A. 

Bondietti (1976) and include determinations of litter urease and amino 

sugar content. Trends disclosed by analyses of these data indicated 

that Crooked Creek Watershed forest-floor biota were undergoing significant changes as a result of exposure to the heavv-metai mnrpntratjops 

found in +hp "H+tflr hnriynnv 

It had been demonstrated that accumulationsjjf 02 litter occur at 

Crooked Creek Watershed sites that had received large inputs of Pb, 

Zn, Cu, and Cd. Similar accumulations of undecomposed organic material 

have been found under apple trees subjected to heavy applications of 

Bordeaux mixture (CuSO.) near Rothamsted, beneath spruce-fir forests 

near heavy-metal industrial activity in southern Sweden, and in the 

oak-litter horizon within 1 km of a Pennsylvania zincjsmelter (Hirst, 

et_al_., 1961; Tyler, 1972; Ruhling and Tyler, 1973; Strojan, 1975). 

The fungicidal activity of heavy-metal ions is well documented (Somers, 

1961) and the lack of litter decomposition in the apple orchard was 

directly attributed to copper poisoning of litter-inhabiting microorganisms (Hirst et^ al_., 1961). Decomposition rates of spruce litter, 

measured by C0~ evolution, were depressed by Pb, Zn, Cu, and Cd concentrations similar to those found on Crooked Creek Watershed (Ruhling and 

81 
82 

Tyler, 1973). A. similar depression of COp evolution was found in litter 

samples collected along one transect of Crooked Creek Watershed (Ausmus 

and Watson, 1975) and in Zn-contaminated litter collected within 6 km of 

the source (Strojan, 1975). These results all indicated a negative 

relationshi p tO exis t between lit+pr HPf-nrnpn<Htinn .inH Titto^ ho.-ivy 

metal content, regardless of the geographical location of the study 

area. 

Further documentation of a heavy metal effect on litter decomposition was provided by analysis of litter amino sugar and urease content 

(Bondietti, 1976). Amino sugars in litter primarily exist as chitin, 

which is resistant to degradation and is not synthesized by green plants. 

Thus, analysis of amino sugars is a specific test for the historical 

presence of decomposer organisms (fungi and arthropods). The results of 

this test on Crooked Creek Watershed litter indicated a marked decrease 

in amino sugars occurred to a distance of 0.8 km from the stack. 

Urease enzyme activity in litter was measured to further indicate 

loss of biological activity on the watershed. This test is more sensitive than the amino sugar assay since the production of urease enzyme is 

adversely influenced by heavy metal contamination. Laboratory experiments on uncontaminated litter showed that the addition of 10,000 ppm Pb 

or 800 ppm Zn caused a 15% reduction in urease enzyme activity. Both 

metal concentrations and enzyme activity in these laboratory studies 

were much higher than those found on the watershed. Thus, it was concluded that the greater observed loss of enzyme activity on the watershed 

was not simple inhibition but may be partially due to a depression in 

microbial activity. A reduction of enzyme activity was found to occur 

to a distance of 2.0 km from the smelter, which was further than the 
P.99 

83 

observed effect on amino sugars. This may indicate that the 2.0 km site 

is presently being slightly affected by the heavy metal emissions. 

The observed decline in fungal and bacterial activity would be 

reflected in arthropod community dynamics because of reduced substrate 

quality. A depression in the fungal populations required to maintain 

fungivores and their predators can be expected to result in a reduction 

of density and biomass for these two arthropod groups. A parallel 

decline may be observed in coprophagous populations dependent upon 

microbial enrichment of their egested litter substrate (McBrayer, 1973; 

Wieser, 1966). Depressed values of density and biomass in predator, 

detritivore, and fungivore populations occurred at heavily contaminated 

sites regardless of distance from the smelter (Tables 14-16). Reduced 

fungivore and detritivore populations were probably due to lack of 

suitable substrate -- few mycelial mats or fruiting bodies were observed 

during field sampling at the affected plots and detritus production 

appeared to be negligible. A similar reduction in density of micro- and 

macroarthropods of litter and soil was observed at study areas located 1 

and 6 km upwind from a Pennsylvania zinc smelter (Strojan, 1972). 

Strojan attributed the population decline to the presence of heavy-metal 

smelter emissions (Zn, Cd, Cu, Pb, and Fe) in forest-floor organic 

horizons. Sulfur dioxide emissions were discounted as causative factors 

due to the neutralizing influence of ZnO (normal litter pH for this area 

is 4.0 to 5.0, litter at the 1 km site was pH 6.1) and the efficiency of 

the smelter's acid plant (Strojan, 1972). The sparse predator populations observed at heavily contaminated sites on Crooked Creek Watershed 

may be due to the lack of suitable prey or the results of toxicity due 
p.1 

84 

to biomagnification. Both hypotheses are supported by the data (Tables 

16 and 24-27). 

The occurrence of measurable disruptions in population density and 

biomass suggested that a corresponding disruption could be occurring in 

arthropod population diversity. It was thought that such a measure 

would give some insight into the stability of the Crooked Creek Watershed litter system. Calculation and subsequent statistical testing of a 

Shannon-Weaver index applied to each site indicated little change in 

arthropod diversity on Crooked Creek Watershed, regardless of litter 

heavy metal load or season (Table 28a) (Shannon, 1948; Hutcheson, 1970). 

When segregated into its two components of richness and evenness of 

abundance (Pielou, 1966; Price, 1975), diversity on the watershed was 

shown to be governed by an even population distribution (Table 28b). In 

contrast, the richness component was shown to be a sensitive indicator 

of the effects due to distance and direction (Table 28c). System parameters of 02 litter mass (Figs. 5 and 6) and macronutrient pools (Fig. 

13) have already demonstrated that disruptions in ecosystem integrity 

are occurring on Crooked Creek Watershed. The inability of the ShannonWeaver index procedure to detect similar disruptions on the population 

level revealed a serious lack of sensitivity of this method to ecosystemlevel perturbations. 

Concentration factor data indicated that neither Pb, Zn, Cu, or 

Cd are presently being concentrated in the litter-litter feeder food 

chain on Crooked Creek Watershed (Tables 24-27). Although lead was the 

most abundant heavy-metal element found on the watershed, it was accumulated in the litter fauna to a much smaller extent than either Zn, Cu, 
P.2 

85 

or Cd. This phenomenon may be due to differences in insect physiological response to each element. 

Copper is a component of the arthropod blood protein hemocyanin, 

which can be found in most insects and isopods and in some amphipod 

and decapod species (Wieser, 1961, 1965; Wigglesworth, 1965). Marine 

arthropods are bathed in copper-containing media and do not possess 

well-developed mechanisms for storage and maintenance of Cu reserves 

(Wieser, 1965). In contrast, terrestrial species must depend upon 

their substrate to fulfill their Cu requirements. One purpose of 

coprophagy in isopods is thought to be maintenance of a critical Cu 

concentration in their substrate, which had been previously thought to 

consist entirely of Cu-poor litter (Wieser, 1966). The greater variation and larger values of Cu concentration factors between litter fauna: 

litter found on Crooked Creek Watershed relative to those for Pb may 

be reflecting the variability in Cu requirements of the fauna (Table 

26). Zinc is required both as a mediator and as a constituent of enzyme 

reactions (Orten, 1966). Physiological requirements for Zn by the 

Crooked Creek Watershed litter fauna appeared to be reflected in the 

m litter fauna:!itter concentration factors, particularly when compared 

;••. to the much smaller values calculated for Pb (Tables 24 and 25). 

Available literature does not document arthropod physiological require-

'*-• ments for Cd. Other than displaying greater accumulation of Cd relative 

I to Pb, the significance of Cd concentration factors for litter fauna: 

litter in Table 27 is not known. Lead is not known to be necessary for 

i plant or animal growth and development. 

t Except for Cu, it has not been possible to substantiate a similar 

food chain dilution of heavy metals from prey to predator on Crooked 
P.3 

86 

Creek Watershed. Concentration factor data indicated that, in relati on 

to their prey, arthropod predators may be either concentrating or equilibrating with respect to Pb, Zn, and Cd. Cadmium is of special interest, for possible biomagnification occurred only in those predator 

populations exposed to prey containing £ 9 ppm Cd. At prey levels 

greater than 9 ppm, all predator concentration factors were less than 1. 

While cadmium can displace Zn in enzyme reactions, it is not physiologically required by arthropods (Underwood, 1971). It is possible that 

high levels of prey Cd may be toxic to their arthropod predators. If 

the lethal dose to spiders and other predators is greater than the 

amount of biologically available Cd in prey containing 9 ppm total Cd, 

then death would result before biomagnification could occur. 

Mineral Cycling 

Remineralization of nutrient ions in litter is a normal component 

of the mineral cycling processes of deciduous forests (Ovington, 1960). 

Earlier discussion has pointed out the role of arthropods in decomposition. It has been suggested that disruption of coupled arthropod and 

microorganism life cycles by heavy metal toxicity may completely disrupt forest mineral cycling (Tyler, 1972; Witkamp and Ausmus, 1975; 

Ausmus e_t aj_., 1975; Jackson and Watson, 1976). Tyler hypothesizes 

that such toxicity would first result in an increase in the amount of 

incompletely decomposed litter material on the forest floor. Reduced 

decomposition rates would allow mineral nutrients to remain bound in 

a form unavailable for plant uptake and may result in an eventual productivity decline. 
P.4 

87 

The first stage of Tyler's hypothesis has been substantiated by 

Crooked Creek Watershed data -- 02 litter accumulations have already 

occurred at a number of sites (Figs. 5-6, Appendix C). The subsequent 

decline in nutrient availability suggested by Tyler was corroborated by 

preliminary measurements of fresh summer leaves collected from Crooked 

Creek Watershed black and white oak (Table 12). Foliage concentrations 

of Ca, K, and P were significantly reduced when compared.to the control 

only at the site with the greatest heavy metal load and litter accumulation. These data suggest a reduction in root uptake. 

During litter sampling, it was observed that secondary roots of 

trees did not occur within and beneath the 02 litter horizon at sites 

near the smelter. At the control sites, considerable difficulty was 

involved in separating litter material from the thick mat of fine 

roots growing throughout the 02 horizon. Greenhouse pot experiments 

utilizing healthy black oak seedlings transplanted to Crooked Creek 

Watershed soil verified the field-observed effects on lateral root 

growth (Jackson and Watson, 1976). 

Further indications of a disruption in nutrient cycling mechanisms 

are the changes in cation exchange capacity and pH from the normal 

state (Table 11). The decline in total litter cation exchange capacity 

on Crooked Creek Watershed(could lead^to a reduced capacity of litter 

to hold nutrient cations, resulting in leaching losses. Thus, after 

initial nutrient binding due to reduced remineralizatiorr (cf. Table 13 -

Ca and Mg pools at 1.2 and 2.0 km, K pool 0.8, 1.2, and 2.0 km), nutrients may be lost entirely from the system (cf. Table 13 - Ca pool at 

0.4 and 0.8 km). This effect goes beyond the two-stage hypothesis of 

Tyler (1972), where primary production, limited by the lack of essential 

JUJBMU" 
P.5 

88 

nutrients bound up in undecomposing litter, declines. 

Phosphorus may become tenaciously bound in organic material and 

thus does not behave in the same manner as divalent macronutrient 

cations. The P pool at 0.4 km was not different from that of the control (Table 13), but the P content of fresh foliage at the same site 

was significantly reduced from that of the control. The capacity of P 

to bind to organic material may be responsible for foliage P depletion. 

In general, forest^nutrient dynamics on Crooked Creek Watershed are 

displaying significant signs of perturbation - excessive root mortality, 

depletedniiaTronutrient concentrations in fresh foliage, a decline in 

cation exchange capacity and litter Ca pools near the smelter, and an 

accumulation of litter Mg and K between 0.8 and 2.0 km of the smelter. 

A major disruption in nutrient resource allocation due to heavy metal 

effects on litter decomposition was indicated. Eventually, it can be 

expected that productivity will be most depressed in trees which are not 

tolerant of heavy metals or a reduced supply of available nutrients. It 

is not unrealistic to envision widespread deforestation of non-tolerant 

species over an area adjoining the smelter, if the smelter emissions 

continue at the present level for a number of years. 

It can be further hypothesized that the area affected by the 

smelter may be increasing in size due to the continual loading of 

heavy metal particulates on the watershed. The area 1.2 - 2.0 km from 

the stack could eventually be affected to the same degree as the existing area within 0.8 km from the stack. 
^ TH ' •- *i? 

P.6 

SUMMARY AND CONCLUSIONS 

A number of measures of biological activity within the Crooked 

Creek Watershed litter system have been made. Studies have focused 

on the litter-arthropod food chain as a means of detecting perturbations in a heavy-metal contaminated terrestrial ecosystem. To adequately characterize the arthropod food base and habitat, litter mass, 

heavy metal content, cation exchange capacity, pH, urease activity, 

and amino sugar content were critically examined. Litter horizons on 

the watershed can be characterized as follows: 

1) 01 litter mass has not differed throughout the watershed 

during the period of study, but varied about a mean of 

433 + 29 (SE) g/m2. Mean annual 01 mass at .the control 

site varied about a mean of 471 +_ 34 (SE) g/m2. 

2) An accumulation of undecomposed 02 litter on CCW was 

positively correlated with litter heavy-metal content 

(P<.01). 

3) The highest concentrations of litter Pb, Zn, Cu, and Cd 

occurred in 02 litter. The mean annual range of values for 

heavy metals (ppm) on the watershed were 4600 to 103000, 

230 to 4910, 80 to 6080, and 14 to 179 for Pb, Zn, Cu, 

and Cd, respectively. Although litter gradually became 

enriched in Zn, Cu, and Cd relative to Pb as distance 

from the smelter increased, the rank order of concentralion-paralleled that displayed by stack emissions, i.e., 

Pb>Zn>Cu>Cd. 

4) Measurements of 02 litter urease activity, amino sugar 

content (Bondietti, 19/b), and LO2 evolutionrevealed a 

depression of normal decomposer activity in Irtter 

collected near heavy metal sources"! 

From these data, it appeared that annual production of fresh 

litter on Crooked Creek Watershed, as estimated by forest-floor 01 

litter mass, had not yet been adversely affected by exposure to smelter 

emissions. In contrast, significant 02 litter accumulations have 

89 

mmm 
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"IT 

occurredas a result of reduced decomposition. Both historical and 

current microbial activity (measured by amino sugar analysis and C02 

evolution) have been depressed at sites located near the AMAX smelter, 

the primary heavy metal source on CCW. Since litter arthropods act 

as "catalysts of microbial metabolism", in decomposition processes 

by substrate alteration and inoculation, any gross changes in litter 

decomposition should be reflected in the dynamics of the arthropod 

community (Macfadyen, 1963). Documented effects on the CCW litter 

arthropod populations were as follows: 

1) When compared to the control site, reduced values ofLtotal __ 

arthropod biomass (mg dry wt/m2) and density (no./m2) occurred 

simultaneously with elevated levels"Of Utter heavy metals. 

2) This reduction in total arthropod biomass and density was 

governed by a decrease in biomass and density of the 

predator, detritivore and fungivore populations. 

3) Measurements of arthropod richness, an estimate of maximum 

diversity, revealed that litter arthropod populations at heavily 

contaminated sites were less rich in taxa (family) than were 

those located elsewhere on the watershed. 

These effects may be induced by changes in substrate quality or actual 

heavy metal toxicity. The latter hypothesis was supported by analytical 

results of heavy metal concentrations found associated with arthropod 

trophic levels. 

Food-chain dilution of Pb, Zn, Cu, and Cd from litter to litter 

consumer occurred as indicated by the mean concentration of 0.7 +_ 0.02 

(SE) (Pb), 0.64 + 0.15 (SE) (Zn), 0.38 + 0.10 (SE) (Cu), and 0.34 + 

0.05 (SE (Cd). Biotransfer of Pb to litter consumers was much less than 

that found for the other three heavy metals. In contrast, predatory 

arthropods on Crooked Creek Watershed were either concentrating or 

equilibrating Pb, Zn, and Cd from their prey, as indicated by mean .