£EPA
United States
Environmental Protection
Agency
Office of Water &
Waste Management
Washington D.C. 20460
SW- 709
September 1978
Solid Waste
Municipal Sludge
Agricultural Utilization
Practices
An Environmental Assessment
Volume I
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MUNICIPAL SLUDGE AGRICULTURAL UTILIZATION PRACTICES
An Environmental Assessment
Volume I
This report (SW-709) was prepared for the Off-ice of Solid Waste
by Kenneth V. LaConde, Ronald J. Lofy} and Robert P. Stearns
under contract no. 68-01-3265.
Direction was provided by Alessi D. Otte and Larry Prior
of the Office of Solid Waste.
U.S. ENVIRONMENTAL PROTECTION AGENCY
1978
-------
This report has been reviewed by the U.S. Environmental Protection
Agency and approved for publication. Its publication does not signify
that the contents necessarily reflect the views and policies of the
U.S. Environmental Protection Agency, nor does mention of commercial
products constitute endorsement or recommendation for use by the
U.S. Government.
An environmental protection publication (SW-709) in the solid waste
management series.
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ABSTRACT
An environmental assessment was performed at nine study sites across
the United States to investigate the effects of utilizing municipal
wastewater treatment plant sludge for agricultural purposes. The sites
represented a wide range of sludge application rates, sludge characteristics,
cropping practices, soils, population densities, and climatological and
geographical conditions. The assessment included evaluative criteria
such as chemical, physical, and microbiological constituents of sludges;
surface and subsurface soil properties including presence and accumulation
of heavy metals, pesticides, nutrients, bacteria, and parasites; plant
characteristics including heavy metal and pesticide uptake, and potential
contamination by bacteria and parasites; public attitudes; landspreading
costs (capital and operational); current and past operating procedures;
and management practices at each of the nine sites.
The project was divided into two phases. Phase I involved a literature
search and an extensive screening program to select the nine study sites.
Phase II involved the sampling and chemical, physical, and microbiological
analyses of over 600 soil, plant, and sludge samples to assess those
criteria mentioned above.
Volume I presents an in-depth analysis of the data including summary,
conclusions, and recommendations. Volume II presents detailed write-ups
of each study site along with a complete record of all the analytical
data.
Volume II is available from the National Technical Information
Service, U.S. Department of Commerce, Springfield, Virginia, publication
number PB-279 357.
iii
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CONTENTS
Page
Abstract iii
Tables .yi
Figures viii
Acknowledgment 1X
I. Summary 1
II. Conclusions 9
III. Recommendations 16
IV. Introduction 18
V. Case Study Site Methodology 20
VI. Summary Description of Case Study Sites 28
VII. Field Sampling Program Scope and
Objectives 41
VIII. Data Analysis 47
Section I - Individual Study Site
Analyses 47
Section II - General Evaluation 99
IX. Bibliography 134
Appendix 147
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TABLES
Number Page
1 Comparison of Physical Parameters for Nine Study
Sites 2
2 Useful Remaining Life of Case Study Sites Based on
Total Metal Loadings and Sludge Characteristics 6
3 Statistically Significant Differences for Metal
Concentrations in Soils 7
4 Statistically Significant Differences for Metal
Concentrations in Plants and Grains 8
5 Statistically Significant Differences in Subsurface
Soil Metal Accumulations l3
6 Comparative Weather Data for 1975 30
7 Comparative Study Site Information 31
8 Comparative Sewage Treatment Plant (STP) Information 33
9 Comparative Sewage Treatment Plant Data 36
10 Summary of Reported Environmental Problems and
Existing State Regulations 39
11 STP Employee Innoculation Program 40
12 Chemical Composition of Stabilized Sludges from All
Study Sites 4g
13 Concentrations of Total and DTPA-Extractable Metals
in Composite Surface and Subsurface Samples from
Macon, Georgia 54
14 Metal Concentrations in Cheatgrass and Oats from
Macon, Georgia 55
15 Nitrogen, Phosphorus, and Metals Applied in Sewage
Treatment Plant Effluent and Sludge- Las Virgenes,
California co
bo
vi
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TABLES (continued)
Number Page
16 Concentrations of Total and DTPA-Extractable
Metals in Composite Surface and Subsurface Samples
from Las Virgenes, California 60
17 Metal Concentrations in Ryegrass from Las
Virgenes, California 62
18 Concentrations of Total and DTPA-Extractable
Metals in Composite Surface and Subsurface
Samples from Wilmington, Ohio 65
19 Metal Concentrations in Alfalfa from Wilmington,
Ohio 67
20 Concentrations of Total and DTPA-Extractable Metals
in Composite Surface and Subsurface Samples from
Springfield, Missouri 70
21 Metal Concentrations in Fescue from Springfield,
Missouri 72
22 Concentrations of Total and DTPA-Extractable
Metals in Composite Surface and Subsurface Samples
from Chippewa Falls, Wisconsin 75
23 Metal Concentrations in Soybeans from Chippewa
Falls, Wisconsin 76
24 Concentrations of Total and DTPA-Extractable Metals
in Composite Surface and Subsurface Samples from
Hopkinsvilie, Kentucky 79
25 Metal Concentrations in Fescue from Hopkinsvi1le,
Kentucky 80
26 Concentrations of Total and DTPA-Extractable Metals
in Composite Surface and Subsurface Samples from
Frankfort, Indiana 84
27 Metal Concentrations in Wheat from Frankfort,
Indiana 85
28 Concentrations of Total and DTPA-Extractable Metals
in Composite Surface and Subsurface Samples from
Kendallville, Indiana 89
29 Metal Concentrations in Alfalfa from Kendal1vi11e,
Indiana 90
vii
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TABLES (continued)
Number Page
30 Concentrations of Total and DTPA-Extractable Metals
in Composite Surface and Subsurface Samples from
Columbus, Indiana 94
31 Metal Concentrations in Corn from Columbus, Indiana 95
32 Chemical Compositions of Sludges for All Sites 98
33 Sludge Cd/Zn Ratios - All Sites 100
34 Quantities of Sludge, P, and Metals Applied, Based
upon Available N for Crops 102
35 Total Amount of Sludge Metals Allowed on Agricul-
tural Land 103
36 Maximum Quantities of Sludge Permitted, Based on
Recommended Metal Loading Limits 104
37 Annual and Total Loading Rates of Sludge and Heavy
Metals 105
38 Comparative Economic Values for Sewage Sludge as
a Fertilizer Source 107
39 Soil Metal Concentrations in Sample Means 108
40 Total Metal Concentrations in Surface Soils 110
41 Comparison of Metal Concentrations in Sludge Treated
Soils with Concentrations Considered Typical for Soils 112
42 Total Metal Concentrations in Composite Surface Soils
forAllSites -j-|4
43 Metal Concentrations of Treated and Control Soil
Composites 115
44 Effects of Sludge Applications on Some Soil Proper-
ties and Concentrations of DTPA-Extractable Heavy
Metals in Surface Soils H8
45 Concentrations of DTPA-Extractable Metals in Composite
Surface Soils for All Sites -|2n
46 Mean Metal Concentrations in Leaf Tissue -|2?
vlii
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TABLES (continued)
Number Page
47 Mean Metal Concentrations in Harvested Grains 123
48 Total Metal Concentrations in Plants 124
49 Chlorinated Hydrocarbon Concentrations in
Stabilized Sludges 127
50 Chlorinated Hydrocarbon Concentrations in
Surface Soil Composites 129
51 Chlorinated Hydrocarbon Concentrations in
Composite Plant Samples 131
FIGURES
Number Page
1 Study Site Locations 29
ix
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ACKNOWLEDGMENTS
We wish to thank Messrs. Alessi Otte and Lawrence Prior,
and Drs. James Ryan and Rufus Chaney for their guidance a
assistance in the preparation of this Draft Final Report, jj!50-
we want to express our appreciation to our consultants on this
project: Drs. Albert L. Page and Parker F- Pratt of the
University of California, Soil Science Department; Leo M. Walsh
of the University of Wisconsin, Department of Soil Sciences;
and David R. Storm of Storm Engineering, Davis, California.
The cooperation and assistance we received from the sewage
treatment plant personnel and the farmers of the case study
sites were sincerely appreciated. The Soil Conservation Service
of the U.S. Department of Agriculture rendered invaluable
service in the field, as well as providing necessary information
for this report. Climatological data was provided by the
National Weather Service, and we thank them for this help. And
finally, we want to thank the state health agencies, local
newspapers, and all others who participated in our investigation
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CHAPTER I
SUMMARY
Agricultural utilization is one of several accepted disposal
methods for municipal sewage treatment plant solids (sewage sludge)
Several university- and federally-sponsored research projects have
been conducted to study the effects of long-range sludge applica-
tions to croplands, but these have generally been limited to the
controlled conditions of test plots. The Environmental Protection
Agency (EPA) Office of Solid Wastes, to advance the knowledge of
actual practices, contracted with SCS Engineers (SCS) to under-
take an environmental assessment of sewage sludge utilization on
cropland at nine study sites. These sites were to be diverse --
encompassing as many types of crops, soils, and sludge charac-
teristics as possible, and representative of sludge spreading
activities as currently practiced.
The project was divided into two phases. The first involved
the establishment of site selection criteria, contact with approxi-
mately 100 municipalities and/or sewage treatment plants, and the
selection of 16 preliminary sites. Field visits were made for
five major reasons:
To obtain detailed information on sludge spreading
programs at each location,
To assess the availability of historical records,
To interview the owners/managers of the farms
receiving sludge,
To select suitable sludge-treated and control plots
for preliminary sampling, and
To obtain sludge, soil, and plant samples for
chemical and physical analyses.
From this assessment and the analytical data, nine sites were
selected for in-depth study in Phase II of the project. Table 1
provides a summary of site characteristics at the nine locations.
All sites shared the following:
Only municipal sewage treatment plant solids were
utilized.
1
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TABLE 1. COMPARISON OF PHYSICAL PARAMETERS FOR NINE STUDY SITES
PO
Site Location
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
Agricultural
Crop
Cheatgrass
Ryegrass
Alfalfa
Fescue
Soybeans
Fescue
Wheat
Alfalfa
Corn
Food Crop Use
Non-dairy cattle feed
Non-dairy cattle feed
Non-dairy cattle feed
Non-dairy cattle feed
4
Open market
Non-dairy cattle feed
Flour mill
Non-dairy cattle feed
Distillary
Surface Soil
Description*
Sandy loam
Clay loam
Silt loam
Silt loam
Sand
Silt loam
Silt loam
Clay loam
Sandy loam
Surface Soil
pHt
3.7
6.5
6.5
7.0
5.5
6.2
6.7
6.4
6.6
*USDA Classification
tO.01 m CaCl2 method
'Crop not harvested because of poor yield
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TABLE 1 (continued)
Site and Location
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
CO
Hopkinsville, KY
Frankfort, IN
Kendall vi lie, IN
Columbus, IN
STP Average
Capacity
(cu m/day)
45,400
17,000
7,600
75,700
13,200
8,300
11,700
6,000
24,400
Population
Equivalent
125,000
75,000
19,000
164,000
51,000
28,710
12,900
22,200
50,000
Estimated Industrial
Type of Secondary Contribution
Treatment (percent flow)
Trickling filter
Activated sludge
Activated sludge
Activated sludge with
Kraus modification
Activated sludge
Trickling filter
Trickling filter
Trickling filter
Activated sludge
30
10
25
15
65
15
30
25
67
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TABLE 1 (continued)
Site Location
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
Reported
Years of
Sludge Spreading
11
7
17
15
6
9
12
13
5
Estimated
Annual Sludge
Application Rate**
(m tons/ha)
MM
28
50
6.8
15.8
16**
OO" "
30**
19.7
65
Cumulative Total
Sludgef
(m tons/ha)
308*
149
116
237
80 W
66^
360 W
81
326
**1975
tThrough Dec. 31, 1975
"'Estimated
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All applied sludge had been stabilized by conven-
tional aerobic or anaerobic processes.
Crops grown in the sludge amended soils were used
for animal or human food.
t Sludge had been applied for a minimum of four
years.
All fields were under active farm management.
Phase II encompassed data gathering at each site and sam-
pling of sludge, surface and subsurface soils, and plants for
physical, chemical, and bacteriological analyses. These data
provided the basis for the ensuing assessment of environmental
impacts at each of the sites. The prescreening and selection of
nine case study sites resulted in an investigation of a wide
variety of different sludges, soils, and plants, although two of
the sites were planted to alfalfa and two to fescue. Because of
these diverse conditions, no direct comparisons between any of
the sites are presented.
Communications between the consultant and responsible offi-
cials at each site were maintained throughout the project. As
conclusions evolved from the assessments, these officials were
afforded the opportunity to review and comment on the findings.
HIGHLIGHTS OF PROJECT FINDINGS
The case study sites were located in seven states.
Three states (Wisconsin, Illinois, and Ohio) had
published guidelines for agricultural utilization
of sewage sludge. The states of Georgia, California,
and Indiana were in the process of adopting similar
guidelines, while neither Missouri nor Kentucky
had initiated guidelines programs.
Record keeping by sewage treatment plants for sludge
utilization practices was found to be incomplete.
Several maintained records of sludge quantities
transported to farms but could not specify spread-
ing areas within the receiving.fields, and one site
kept virtually no sludge distribution records what-
soever. Farm owners/managers receiving sludge had
not recorded sludge quantities received nor the
locations for spreading on their farms.
t In general, the public officials interviewed were
not fully cognizant of the sludge utilization prac-
tices within their respective communities. None
expressed concern for ongoing sludge utilization
practices, and local health officials reported no
instance of health problems attributed to sludge
utilization practices at any of the nine sites.
5
-------
Sludge utilization practices at two sites had minimal
adverse environmental impacts. Ironically, however,
sludge spreading at both sites has been halted. Spread-
ing at one site ceased because of an isolated odor
complaint arising from the field-drying process for the
sludge. (Other utilization sites within the near
vicinity were not affected.) The other site was
located on marginal agricultural land and was recently
sold to the city for park development.
Of the nine case study sites, only two exhibited the
potential for significant adverse environmental impact:
one utilized a sludge containing high concentrations of
Cd; the other disposed of sludge on highly-acidic,
coarse textured soil in close proximity to the ground-
water.
Table 2 presents an analysis of the remaining useful
life of the sites, based upon the following assumptions:
The chemical composition of each sludge will remain
constant at the levels found during the study.
Guidelines proposed by the North Central Regional
Committee NC 118 (1976), based on CEC and total
metal loadings, are used as evaluating criteria.
TABLE 2. USEFUL REMAINING LIFE OF CASE STUDY SITES BASED
ON TOTAL METAL LOADINGS AND SLUDGE CHARACTERISTICS**
Site
Cd
Cu
Years
Ni
Pb
Zn
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI#
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
49
33
246
7.5
84
117
0
16
49
8
8
162
24
6
38
0
31
15
40
77
963
27
308
149
1
123
14
106
997
248
829
620
1 ,007
254
9
251
9
12
0
4
21
28
4
3
16
*CEC of all surface soils, except Chippewa Falls, WI, was > 15
tAs of January 1, 1976.
#CEC < 5.
From the table, the disposal sites at Wilmington, Ohio and
Frankfort, Indiana, have surface metal concentrations exceeding
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the proposed guidelines. Using NC 118 criteria, then, these two
sites have no useful remaining life for sludge utilization.
In general, there was close analytical agreement between
soil and plant composites and the means of the five
individual section samples from which the composites
were derived. This indicates that the samples accurately
represented field conditions. Statistically significant
differences at the 90 percent confidence level (treated
versus control) in terms of Cd, Cu, Ni, and Zn concentra-
tions contained in surface and subsurface soils are
shown in Table 3.
TABLE 3. STATISTICALLY SIGNIFICANT DIFFERENCES FOR
METAL CONCENTRATIONS IN SOILS*
Site Cd Cu Ni Zn
Macon, 6A
Las Virgenes
Wilmington,
Spri ngf i el d ,
Chippewa Fal
Hopkinsville
Frankfort, I
Kendall vil le
Columbus, IN
»
OH
CA
MO
Is
>
N
9
, HI
KY
IN
St
--
--
S
--
S,l
S,l,2
S
S
s,
S
--
s,
s,
s
s,
s,
1
1
1,2
1
3,4
S
S
--
s,
--
s,
s
s,
s,
1
1
1,2,3,4
4
S
S
S
S
s
s
s
s
s
,1
,1
,1
,1
,3
,2,3
,2
,4
.4*
*Significant at the 90 percent confidence level.
tSurface soil.
#Depths (1 - shallowest; 4 - bottom depth to 122 cm).
Similarly, statistically significant differences at the
90 percent confidence level (treated versus control
plots) were observed for Cd, Cu, Ni and Zn concentrations
in plants and grains. These data are presented in
Table 4 (on the following page), in general, however, the
concentration of metals reported were within ranges not
considered hazardous to health or phytotoxic to plants
except for Zn at Macon, GA (phytotoxic range) and Cd at
Frankfort, IN (potential health concern).
o Liquid sludge spreading costs in the study locations
ranged from $7.98 to $79.08 per dry m ton. One site
employing sludge dewatering incurred costs of $128.07
per dry.m ton.
o The study results tend to confirm that with proper site
management and crop selection, as well as careful
attention to soil, crop, and sludge compatibility,
little or no adverse environmental impacts will result
from sludge utilization for agricultural purposes.
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TASpTflf'rnSI^STICALLY SIGNIFICANT DIFFERENCES FOR
METAL CONCENTRATIONS IN PLANTS AND GRAINS*
Site
Plant/Grain
Cd Cu
Ni
Zn
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendalville, IN
Columbus, IN
Cheatgrass
Ryegrass
Alfalfa
Fescue
Soybean petioles
Soybeans
Fescue
Wheat - Immature bud,
stalk, leaves
Wheat - Grains
Alfalfa
Corn - leaves
Corn - grain
*Significant at the 90 percent level.
+Denotes significant difference.
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CHAPTER II
CONCLUSIONS
Conclusions, as presented in this chapter, have been
divided into the following categories:
General,
Sludge Related,
Soil and Plant Related,
Site Specific, and
Sludge Management.
The site specific category is a capsulation of conclusions
to be found in Chapter VIII, Section I. The other categories
present statements, tables, and data excerpted and condensed
from Chapter VIII, Sections I and II. The reader is advised to
review Chapter VIII in its entirety for an in-depth analysis of
all supportive data.
GENERAL
Interviews with local health officials and site personnel
revealed no reported health problems associated with the
sludge utilization practices at the study sites.
No adverse comments on the sludge utilization practices
were received from state, county, or city officials
contacted during the project. However, some officials
were not fully cognizant of local practices.
Two sites had no useful remaining life for receipt of
sludge based on cumulative metal loadings to date and
guidelines proposed by the North Central Regional
Committee NC 118 (1976). They were Wilmington, Ohio
(excess Zn loadings), and Frankfort, Indiana (excess Cd
and Cu loadings).
Concentrations of DDT in sludge ranged from 0.9 to 160
ppb. The highest DDT residual found in the soil was
0.29 ppb.
Detectable concentrations of dieldrin, ranging from 0.4
to 114 ppb, were found in the sludges from five sites.
-------
Detectable concentrations of dieldrin were found in
surface soils at six sites. The maximum concentration
detected was 0.84 ppm.
In the respective sludges, polychlorinated biphenyls
(RGB's) were detected in measurable quantities at all
locations except one. The maximum concentration measured
was 5,872 ppb with five others exhibiting concentrations
above 3,300 ppb.
PCB's were detected in the surface soil at all but two
sites. A significant decrease in concentration occurred
between sludge and soil values observed.
PCB's were found in or on plants at two locations. The
highest plant PCB concentration level was 0.4 ppb which
is near the detection limit.
An economic analysis of the sludge disposal costs at
eight sites utilizing liquid sludge showed a range of
$7.98 to $79.08 per m ton (dry-weight basis). At the
Las Virgenes site, where sludge was dewatered, the cost
was $128.07 per m ton (dry-weight basis).
The microbiological findings (total aerobes, salmonella,
shigella, fecal coliforms, and fecal streptococci)
revealed no significant deviations from occurrence or
concentration levels commonly observed in municipal
sludges. The soil and plant data in general compared
well to similar studies. Where results were atypical,
they could in part be attributed to the limited number
of analyses performed.
Salmonella sp. organisms were not isolated in any of the
stabilized sludges. This finding supports other related
research which has shown that Salmonella sp. and
Shigella sp. organisms do not normally survive sludge
stabilization processes.
Salmonel1 a sp. (Salmonelia paratyphi £.) was isolated
in one of 88 composite soil samples examined.
No Salmonella sp. or Shigella sp. organisms were
detected in any of the plant samples.
The failure to detect parasitic helminth ova in some of
the sludge samples appeared to be atypical based on
similar studies. This can be attributed to the random
sampling, the small number of samples, and the tendency
for the helminth ova to sediment out during the sludge
stabilization residence time.
10
-------
Similarly, no parasitic helminth ova were detected in
any of the composite surface soil samples.
The percent DTPA extractable metals (based on total
metals) was, in almost every instance, greater in surface
than subsurface soils, suggesting that metals in sludges
are more soluble in DTPA than those naturally present
in the soil.
In most cases, the percent of Cd extracted with DTPA
was higher than those of Cu, Ni , or Zn.
The percent of total metals extracted by DTPA, in most
cases, increased in proportion to the organic carbon
concentration of the soil.
SLUDGE RELATED
In terms of nitrogen (N) and phosphorus (P), the sludges
represented an unbalanced but significant fertilizer
resource. Calculated equivalent fertilizer values
ranged from a low of $11.79 per m ton (dry basis) to a
high of $40.18, assuming 50 percent of the ammonia-N and
20 percent of the organic-M are available in any one
year, and that 100 percent of the P is plant available.
All sludges were more valuable in terms of P than N.
Sludges at all sites were distributed over the soil
surface resulting in ammonia loss by volatilization.
If the sludge were incorporated into the soil, it would
have an increased value as a source of N.
The cumulative total addition of Cd ranged from 0.5 to
13.3 kg/ha at eight of the nine sites, while annual Cd
loading rates at these sites ranged from 0.08 to 1.0
kg/ha. The ninth site had a cumulative total Cd loading
of 540 kg/ha, and an annual Cd loading rate of 45 kg/ha.
If sludge application rates are based on 200 kg/ha
available N, two locations would add Cd in excess of
maximum levels proposed by the North Central Regional
Committee, NC 118 (1976).
Based on 1975 actual application rates, and the annual
maximum Cd loading of 2.0 kg/ha as recommended by the
EPA Municipal Sludge Management Technical Bulletin,
utilization practices at one of the nine sites resulted
in Cd quantities in excess of this maximum.
SOIL AND PLANT RELATED
The Cd concentration in the soil profile (treated and
control plots) at the Las Virgenes, California, site
was unusually high (approximately 4 yg/g). However,
the source of Cd was considered to be of natural
origin and not the result of sludge spreading.
11
-------
Small differences in metal concentrations between
treated and control subsurface soil sections and within
depth increments were in some instances statistically
significant in a 90 percent confidence level. However,
in all of these cases, the concentrations determined
were within the ranges typically reported for soils (see
Table 40) and, in most cases, considerably less than
those of the treated surface soil. The data show that
metals applied have remained in the depth of incorpora-
tion'with the following exceptions:
Macon, Georgia - Total and DTPA Zn concentrations
indicate that Zn has migrated to the 122 cm depth.
Frankfort, Indiana - Total and DTPA Cd concentrations
indicate that Cd has migrated to a depth of 61 cm
and possibly 91 cm.
The depth of metal movement (Zn) was greatest in coarse-
textured, acid soils.
Metal accumulations in soil at the surface of the
treated plots as a result of sludge spreading were
significantly higher (90 percent confidence level) than
the control plots at all sites with the following
exceptions:
Las Virgenes, CA - Cd
Wilmington, OH - Cd, Ni
Spri ngfield, MO - Cu
Chippewa Falls, WI - Cd, Ni
Kendallville, IN - Cd
Similarly, subsurface metal accumulations at varying
depths of the treated plots were significantly higher
(90 percent confidence level) than those of the control
plots as shown in Table 5 (see next page)-
The subsurface soil data suggest that potential ground-
water contamination from surface sludge spreading
operations is remote except at Macon, Georgia, where Zn
has migrated to a soil depth of 122 cm. The groundwater
table at this site is located between 120 and 150 cm.
Statistically significant differences (90 percent confi-
dence level) were observed in a majority of plant and
grain Cd, Cu, Ni, and Zn concentrations. In general
however, the concentrations of metals reported were
within ranges considered normal except for the following1
12
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TABLE 5. STATISTICALLY SIGNIFICANT DIFFERENCES IN
SUBSURFACE SOIL METAL ACCUMULATIONS*
Site Cd Cu Ni Zn
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
_ _
--
--
--
--
1
1,2
--
_ _
1
--
--
1
1,2
--
1
3,4
- _
--
--
1
--
1
--
1,2,3,4
4
l,2,3,4t
__
1,2
-_
1
1
3,4
*90 percent confidence level.
fDepths (1 - shallowest; 4 - bottom depth to 122 cm).
Macon, Georgia - Zn concentrations in cheatgrass
(Bromus Tectorum) ranged from 341 to 455 yg/g
(averaging 383 yg/g), a level considered phytotoxic
to some plant species.
Frankfort, Indiana - Cd concentrations in wheat
grains ranged from 0.58 to 1.89 yg/g (averaging 1.26
yg/g). Based on an average daily human consumption
of 100 g of this wheat, the maximum amount of
Cd recommended by the World Health Organization wou1d
be exceeded.
SITE SPECIFIC
Site specific conclusions regarding acceptability of
sludges, soils, and plants are based on recommendations as
outlined in the North Central Regional Committee NC 118 Report
(1976);see Table 35.
Macon, Georgia
With the possible exception of Se concentrations, the
sludge was suitable for agricultural utilization.
However, excessive annual sludge applications, site
soil properties, shallow depth to groundwater, and high
rainfall have created conditions that greatly enhance
plant uptake and movement of heavy metals (e.g., Cu and
Zn) to lower soil depths.
§ The data suggest that Zn may be migrating through the
soil, and that groundwater contamination from Zn and
other anions (N03, Cl, 504, etc.) may be occurring.
13
-------
Las Virgenes, California
The utilization of sludge has had little or no impact
on trace metal uptakes in plants.
Large amounts of nitrogen, considerably in excess of
those needed by the crop, have been applied via irriga-
tion using wastewaters. It is possible that groundwater
N03-N contamination may occur, if these applications
continue.
Wilmington, Ohio
The limiting factor to agricultural utilization. of this
sludge is probably the exceedingly high Zn content.
The treated plot soil has been substantially enriched
with Zn, but this condition has not yet resulted in
significant increases in the Zn levels of alfalfa.
DTPA Zn indicates possible Zn movement to a depth of
61 cm in the soil.
Springfield, Missouri
The sludge did not contain excessive concentrations of
heavy metals and appears to be a good source of plant nutrients
for the fescue grown at the sludge-treated site.
Chippewa Falls, Wisconsin
The possibility of groundwater contamination appears remote,
in view of the restricted heavy metal movement and the low total
sludge loadings.
Hopkinsvi11e, Kentucky
t The landspreading practices have not. resulted in
elevated concentrations of heavy metals in the fescue
forage.
DTPA analyses suggest limited movement of Cu and Zn to
a depth of 30 cm in the soil.
Frankfort, Indiana
The high Cd concentration of the sludge indicates that
it is not suitable for util.ization on agricultural land.
Total and DTPA-extractable analyses indicate that Cd and
possibly Zn have migrated to at least the 61-cm level in
the soil.
14
-------
The high application rates and elevated Cd in the sludge
and soil pose an undesirable public health condition.
Kendal1vi11e, Indiana
The high concentrations of Zn in the soils have resulted
in elevated Zn concentrations in the alfalfa crop.
The Pb enrichment of the treated soils has not resulted
in elevated Pb alfalfa levels.
Cu and Zn results indicate possible limited movement to
a soil depth of 30 cm.
Columbus, Indiana
No significant heavy metal increases were observed in
corn grains.
Variations noted in subsurface metal concentrations may
have resulted from extensive earth moving in the field
in early 1975.
The concentrations of Cd in corn leaves obtained from
the treated plot were significantly higher than the
control plot leaves, the difference being 0.88 yg/g.
Similarly, Ni and Zn differences showed statistically
significant differences of 3.44 and 18.94 yg/g, respec-
tively.
SLUDGE MANAGEMENT
The maintenance of sewage treatment plant records for
various aspects of sludge management was found to be
lacking or incomplete. Several plants had maintained
records of sludge quantities transported to farms, but
could not identify spreading areas within the receiving
fields. One plant kept virtually no sludge distribution
records whatsoever. None of the receiving farm owners/
managers had ever recorded the sludge quantity received
nor the spreading locations on their farms.
The study results tend to confirm that proper site
management and crop selection, as well as careful atten-
tion to soil, crop and sludge compatibility, can ensure
that little or no adverse environmental impacts will
occur.
15
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CHAPTER III
RECOMMENDATIONS
The following recommendations are a summary of the finding
of the environmental assessment at each site. They do not address
the widely recognized parameters of soil pH, and annual or
cumulative metal additions used to limit the movement of metals
from sludge to plants. These controls are not discussed
because the study was not designed to compare the impacts at
one site to the other sites. EPA has published a Municipal Sludge
Management - Technical Bulletin (Nov. 2, 1977; FR 57420) which
does give guidance in these areas, specific criteria and guideline;
for landspreading of sludge are currently under development which
will give specific operational controls.
Maintenance of historical documentation by a responsible
party should be considered for sludge utilization programs.
Considerations should include:
Quantities of sludge spread, on both wet and dry
weight basis, with dates and field locations
- Crops grown on treated fields
Results of all analyses performed. (e.g. sludge,
soils, etc.)
The analyses to be performed on soils and sludges are
site specific, but in general, sludges should be charac-
terized as to percent solids, NH4-N, total kjeldahl N
(TKN), and other constituents as suggested by industrial
discharges to the wastewater treatment plant.
Surface and subsurface soil characteristics of interest
include pH, heavy metal concentrations (Cds Cu, Ni ,
Pb, Zn, and other metals of concern known to be in the
sludge), TKN, and P. Plant characteristics of interest
include plant yield and heavy metal uptake.
Communities contemplating agricultural utilization of
sludges should consider industrial discharge standards
to mitigate concentrations of undesirable pollutants
in the sludge.
16
-------
Consideration should be given to a program to identify
soil types throughout the United States which have
naturally high Cd concentrations and to determine if
crops grown on these soils pose potential health
problems. This recommendation is made because the
control plot soil at the Las Virgenes site had an
unusually high Cd concentration 3 to 4 yg/g compared
to a typical U.S. range of 0.1 to 0.5 yg/g. A literature
review showed that Burea, e_t a 1 . , 1973, reported that
soil series in California similar to those sampled at
Las Virgenes have Cd concentrations as great as, or everr
greater.
Good judgement should be exercised in implementing an
agricultural utilization program for sludge to assess
such factors as groundwater elevations and soil proper-
ties (texture, pH, water holding capacity, organic matter,
etc.) prior to the implementation of any program.
17
-------
CHAPTER IV
INTRODUCTION
The disposal of municipal sewage sludge is a major en-
vironmental and technological problem of our time. Increasing
quantities of sewage sludge must be disposed of in an environ-
mentally acceptable manner, as a direct result of many factors.
Foremost among these is the Federal Water Pollution Control Act
of 1972 (PL 92-500) which mandates higher wastewater treatment
removal efficiencies of various pollutants. The oil embargo
and shortage of natural gas, which resulted in increased costs
for energy and has caused many communities to minimize use of
sludge conditioning, pretreatment, or incineration facilities,
is another factor in this problem.
To add to this dilemma, the disposal of sewage sludge to
the oceans or other water bodies, long the primary disposal
method for many metropolitan areas, is currently being phased
out. Other expedient disposal methods previously used include:
Subsurface disposal techniques;
t Evaporative and percolation lagoons/ponds,
followed by land disposal;
Landspreading on non-productive land;
Landspreading as a soil amendment for agricultural
and/or forest land; and
Incineration.
Since these disposal methods were utilized with little thought
given to their environmental effects, they are now being in-
vestigated and/or re-evaluated. This report represents one of
those investigations: an environmental assessment of the
landspreadfng of municipal wastewater treatment sludge for
agricultural purposes.
Nine 1andspreading sites representing a wide range of
sludge application rates and characteristics, cropping practices,
soils, climatological and geological conditions, and population
densities were selected for study. Sludge characteristics,
plant uptake and accumulation of heavy metals in soils, past
18
-------
and current operating procedures, public attitudes, and land-
spreading costs were assessed at each location.
The study consisted of two separate phases. Phase I
involved identification and preliminary screening of potential
sites for inclusion in Phase II. Site visits were made to 16
locations meeting desired selection criteria: to validate
reported information; sample sludge, surface soils, and plant
life; and more accurately assess the desirability of each site
for inclusion in Phase II.
Phase II involved a comprehensive and much more detailed
on-site investigation at 9 locations selected from 16 Phase I
sites. Data obtained during these investigations are summarized
for each site in Volume II. These data provide the basis for
the detailed individual and comparative site analyses for en-
vironmental impact to follow in this vo.lume.
Guidelines can be developed from the results of this and
other OSW projects to aid communities in selecting sludge
management methods that are both cost effective and environ-
mentally acceptable.
19
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CHAPTER V
CASE STUDY SITE METHODOLOGY
SITE SELECTION CRITERIA
At project initiation, various criteria were identified
for use in selecting and screening prospective case study sites.
Criteria are listed below:
1. The site must be 2 ha (5 ac) or larger in area;
2. The site must have received sludge for at least
five years and must have been used within one of
the- past three years;
3. The sludge solids applied must
have originated from a municipal treatment plant,
have been stabilized prior to application,
have been applied at a rate greater than 11 m
tons/ha/yr (5 tons/acre/yr), and
not be heat dried;
4. Septic tank wastes and industrial sludges were not
allowed unless incorporated into the municipal waste-
water stream prior to treatment by the municipal
facility;
5. Several sites receiving dewatered sludge of 15 to
30 percent solids were preferred;
6. The site must have been used for agricultural
purposes since the sludge had been applied;
7. Proprietors of the site had to be willing to
cooperate throughout the study;
8. Collectively, sites were to represent a wide range of
sewage solids application rates, soil characteristics,
farming practices, geographical locations, and actual
or potential environmental impacts; and
20
-------
9. A control site with soil and crop characteristics,
similar to the study site but not receiving sludge,
must have been available.
In addition, the availability of historical information and
operating records for each prospective site was desirable.
This included:
Farming practices;
t Types of soils;
Uses of land prior to application of sludge;
f Number of years, relative frequency, sources and
quantities of sewage sludge applied over the years;
Crop yields; and
t Ultimate use planned for the land.
If a site was or had been part of a demonstration research,
or evaluation program, it was not considered for this study.
The intent of the study was to have relatively unknown sites
investigated in order to further the knowledge of soil amend-
ment through sludge spreading.
SITE SCREENING METHODOLOGY
Several sources were used to develop a prospective site
listing, including: EPA Report No. 670/2-75.049 (Review of
Landspreading of Liquid Municipal Sludge by Battelle Research)
dated June 1975; literature about related projects; and
knowledge of the project team. Letters were sent to state
solid waste management and wastewater quality control agencies
requesting their assistance in identifying prospective sites.
A tentative site listing was prepared and telephone calls
were made to 95 sewage treatment plants and/or communities
In 24 states to further determine whether or not the pro-
spective site met the selection criteria. Primarily, the basic
eligibility of the study site was established by telephone.
Information requested from these telephone contacts included:
Amount of industrial waste received by the treatment
plant;
Amount of sludge applied to agricultural land;
t Type of sludge processing or pretreatment performed
at the STP;
21
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Availability of sludge spreading data, e.g., cost
of spreading, chemical analyses of sludge, etc.;
Number of years that sewage sludge had been applied
to the land;
Method of sewage sludge application;
Identification of farmers receiving sludge;
Distance from STP to farms; and
Willingness to cooperate in the study.
Sites continuing to appear promising were identified, and
telephone calls were made to the farmers receiving sludge for
the following information:
t Willingness to cooperate in the study;
General soil types;
0 Distance of treated area(s) from the nearest well,
groundwater, and surface water;
Number of acres to which the sludge had been applied;
t Number of years the sludge had been applied;
t Method of sludge application and any problems
associated therewith;
Rate of application (tons/acre/yr);
Frequency of application;
Type of crops grown; and
Availability of a control site.
If the prospective sites remained within the selection
criteria, additional telephone calls were made to the U.S.
Department of Agriculture, Soil Conservation Service (SCS)
offices to request:
Soil survey maps for the areas under consideration;
and
Specific information about soils and topography of
the potential study site and a nearby control site.
22
-------
The 16 candidate sites ultimately selected met, to the
maximum degree, the selection criteria and responded more
favorably to the questions than those which were not con-
sidered. These sites were:
Las Virgenes, CA Kendallville, IN
Marshall, MO Hopkinsville, KY
Springfield, MO Wilmington, OH
Chippewa Falls, WI Xenia, OH
Dixon, IL Bethlehem, PA
Litchfield, IL Easton, PA
Columbus, IN Macon, GA
Frankfort, IN Danville, VA
PHASE I SITE VISITATION AND SAMPLING
Personal visits were made to each of the 16 selected sites
In-depth questioning made possible a more complete description
of each site, further substantiating the telephone data, and
facilitated an assessment of the prospective site relative to
the selection criteria.
Specific inquiries were made to obtain:
1. Detailed records from the farmer pertaining to
Crops,
Yields,
Fertilizer and pesticide application, and
Sludge spreading;
2. Detailed records of the treatment processes at the
STP, sludge analyses, and data available relative
to agricultural utilization of the sludge;
3. Personal knowledge of both STP and farms which
correlated the new data with the telephone inter-
views and established a basis for later evaluation
of site adequacy for inclusion in Phase II;
4. A further verbal commitment from STP and farmers
to cooperate through later phases of the project;
and
5. Sludge, surface soil, and plant tissue samples
for an initial assessment of sludge spreading
effects.
23
-------
Samples were obtained as follows:
SIudge
A single composite sludge sample consisting of several
grab subsamples was taken at each STP and analyzed for:
pH calcium (Ca)
moisture content chromium (Cr)
volatile solids (V.S.) cobalt (Co)
chlorides (Cl) copper (Cu)
sulfates (504) iron (Fe)
organic nitrogen lead (Pb)
nitrate-nitrogen (NOs-N) magnesium (Mg)
ammonia-nitrogen (NH4-N) manganese (Mn)
boron (B) mercury (Hg)
potassium (K) molybdenum (Mo)
phosphorus (P) nickel (Ni)
sodium (Na) selenium (Se)
arsenic (As) silver (Ag)
cadmium (Cd) zinc (Zn)
Initial analysis used emission spectroscopy; Cd, Cu, Ni, Pb,
and Zn were also analyzed using flame atomic absorption (AA)
techniques.
Soils
Fifty representative soil borings were taken with a 2.5
cm (1 in) diameter stainless steel split-tube sampler to a
depth of approximately 20.3 cm (8 in) from plots in both treated
and control fields, composited, and analyzed for pH, Cd, Cu,
Ni, Zn, and Pb (metals by AA).
Plants
Approximately 1.8 kg (4 Ibs) of representative plant
tissues (where available) were obtained from the treated and
control fields and analyzed by AA techniques for Cd, Cu, Ni,
Pb, and Zn.
PHASE II SITE SELECTION
As a result of the in-depth questions, sampling, and
personal observations, additional information was now avail-
able such as:
Evaluative data including the results of sludge,
surface soil, and plant chemical analyses;
Calculations of soil accumulation and plant uptake of
heavy metals in relation to total sludge loadings;
24
-------
Personal observations of the. quality of the record
keeping by farm and STP management, as well as the
degree of cooperation that could be expected; and
Brief but comprehensive descriptions and reports
of each study site.
At a December 1975 meeting of all project participants
(.contractor, EPA, and project consultants), the 16 Phase I
sites were reviewed and the nine sites listed below chosen as
best representing diverse crops, management practices, climate;
and soil conditions desired for study in this project.
Las Virgenes, CA
Macon, GA
Columbus, IN
Frankfort, IN
Kendallville, IN
Hopkinsville, KY
Springfield, MO
Wilmington, OH
Chippewa Falls, WI
PHASE II SITE VISITATION AND SAMPLING
Site characterization, site analysis, and case study
development were performed in Phase II. The information
sought was similar to that identified in Phase I, but more
comprehensive and expanded to include public opinion of sludge
management practices in the case study locations.
Interviews
Interviews conducted with farmers, STP personnel, Soil
Conservation Service officials, and others confirmed informa-
tion obtained in Phase I and gathered more details concerning
the following:
Farmei
t Field preparation techniques:
Soil preparation for planting,
Equipment used for field preparation, and
Tilling depths for soil;
Field additives:
U-se of fertilizers, pesticides, herbicides, and
25
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- Incorporation of field additives into/onto the
soiIs/plants;
Crop rotation practices;
Irrigation techniques, if any;
0 Yields, historical and current, when available;
Complaints from neighbors and/or other farmers
concerning the use or handling of sludge;
Health problems either personal or related to the
handling of sludge or with ingestion by people
or animals of crops grown on the sludge amended
fields; and
End use of the crop(s) grown on the treated land.
Treatment Plant (STP)--
Detailed descriptions of the treatment process;
Records of amounts of sludge distributed monthly
and/or annually to each study site for each farm's
sludge-spreading history;
Copies of the last 12 month's STP operating records;
A history of capital equipment purchases necessary
for the sludge spreading operation (including age,
date of purchase, and use);
Records of labor, operation and maintenance (O&M),
energy, chemicals, and other costs incurred for
sludge disposal to the land; and
Any physical, health, transportation, regulatory,
or environmental problems associated with the
spreading of sewage solids.
Soil Conservation Service (SCS)--
Knowledge of soil conditions in the general area
of both treated and control fields;
Verification of the soil series of both plots; and
Opinions of environmental effects of the sludge
spreading operation.
26
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Other--
Local newspapers, city and county sanitarians, county
departments of health, and other city and county officials
were queried regarding:
General public opinion of the use of sewage sludge
as a soil amendment;
t Knowledge of any problems (environmental, health,
etc.) associated with or assumed to be the result
of the practice; and
Existence of any newspaper articles, pro or con, on
the spreading of sewage sludge.
Sampling Program
At the same time information was being assembled on the
above, an extensive sludge, soil, and plant sampling program
was being performed as described in detail in Chapter VI;
analytical procedures are described in the appendix of this
volume.
27
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CHAPTER VI
SUMMARY DESCRIPTION OF CASE STUDY SITES
The selected case study sites encompassed a wide range of
study conditions, including geographical location; climate;
crops; STP operating techniques; and sludge generation, spread-
ing, and disposal practices. Volume II of this report contains
a detailed description of each case study site, and the results
of the sampling program performed at each location.
LOCATION
Figure 1 indicates the geographical location of each of the
nine case study sites in the U.S. Three sites were located in
Indiana, and one each in California, Georgia, Kentucky, Missouri,
Ohio, and Wisconsin.
CLIMATE
The climatological conditions at the case study locations
showed wide variation, ranging from a semi-arid southern
California site (Las Virgenes) to severe winter conditions at
Chippewa Falls, Wisconsin, and southern humidity at Macon,
Georgia. Selected climatological factors for each location are
presented on Table 6.
CROPS
Comparative information on crops grown at each of the nine
sites is shown in Table 7. Two of the sites were planted in
alfalfa and two in fescue; the remaining five were in wheat,
cheatgrass, corn, soybeans, and ryegrass. Eight sites had
identical treated and control crops; however, at Macon, Georgia,
the treated crop was cheatgrass and the control crop, oats.
Three of the sites produced crops for human consumption:
wheat at Frankfort, Indiana; corn at Columbus, Indiana; and
soybeans at Chippewa Falls, Wisconsin. The remaining six sites
produced animal feed crops, none for dairy cattle use.
STP INFORMATION
Comparative STP information is presented in Table 8.
Average daily influent to the STP's ranged from a low of 6,000
28
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Figure 1. Study site locations.
-------
TABLE 6. COMPARATIVE WEATHER DATA FOR 1975
Site
Precipitation (in)
Snow,
Water Equiv. Ice Pellets Averages ( F)
Max Max Daily Daily
Temperature
Mean No. of Days
Maximum Minimum
90° & 32° & 32° & 0° &
Total 24 hr Total 24 hr Max. Min. Monthly Above Below Below Below
CO
o
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KYf
Frankfort, IN#
Kendallville, IN
Columbus, IN
55.48
10.70
44.23
53.94
26.44
47.67
37.92
36.73
46.72
3.23
1.84
2.25
4.83
n.d*
6.30
4.45
1.92
3.73
0
0
16.6
35.2
63.6
10.7
21.2
27.1
34.8
0
0
3.9
11.9
n.d.*
12.0
8.0
4.9
5.3
75.9
7.19
64.9
67.0
55.9
68.9
61.4
59.4
62.2
53.5
54.1
44.9
44.4
36.4
45.5
40.0
41.4
43.4
64.7
63.0
54.9
55.7
46.2
57.2
50.7
50.4
52.8
46
10
35
47
28
53
23
10
8
0
0
9
13
81
13
37
39
25
37
0
99
105
156
98
138
137
120
0
0
0
0
22
2
8
2
2
*No data
tMeans - revised 1972
#Means - revised
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TABLE 7. COMPARATIVE STUDY SITE INFORMATION
Site
Macon, 6A
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
Treated
Plot Crop
cheatgrass*
ryegrass
alfalfa
fescue
soybeans
fescue
wheat
alfalfa
corn
Crop Rotation
Cycles
none
none
alfalfa-corn
oats
various
none
none
wheat-corn
corn-soybeans-
oats-alfalfa
none
Crop Use
non-dairy
cattle feed
non -dairy
cattle feed
non-dairy
cattle feed
non -dairy
cattle feed
open-market
non-dairy
cattle feed
flour mill
non-dairy
cattle feed
distillery
Average Annual
Precipitation
(cm)
112.9
35.7
99.2
100.8
73.9
121.3
96.3
90.9
98.4
*Control plot crops from all sites were the same as the treated plot except Macon, GA where control
crop was oats.
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TABLE 7 (continued)
CO
ro
Sludge Application
Site
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
Surface
Soil Type*
sandy loam
clay loam
silt loam
silt loam
sand
silt loam
silt loam
clay loam
sandy loam
Depth to
Groundwatert
(m)
1.5
213
18
41
23
10
21
30
5
Total Sludge
Treated Area
(ha)
50.6
7.3
22.7
12.6
56.7
21
18.5
40.5
14.2
Rates
Annual* Total**
(m tons/ha)
28 t
50
6.8
15.8
16 t
22 t
30 t
19.7
65
308f
149
116
237
80 1
66t
360 f
81
326
Years of
Sludge
Spreading**
11
7
17
15
6
.9
12
13
5
*USDA Classification
tAll ground water depths reported as estimated static levels
#1975
** Through Dec. 31, 1975
tEstimated
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TABLE 8. COMPARATIVE SEWAGE TREATMENT PLANT (STP) INFORMATION
STP
Macon, GA
Las Virgenes, CA
Wilmington, Ofl
Sprinofield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
Average Flow
Capacity
(cu m/day)
45,400
17,000
7,600
75,700
13,200
8,300
11,700
6,000
24,400
Population
(1975)
107,000
40,000
10,000
135,000
12,500
21,250
15,000
9,200
26,500
Estimated Industrial
Population Type of Secondary Contribution
Equivalent* Treatment (percent)
125,000
75,000
19,000
164,000
51,000
28,710
12,900
22,700
50,000
Trickling filter
Activated sludge
Activated sludge
Activated sludge
w/Kraus modification
Activated sludge
Trickling filter
Trickling filter
Trickling filter
Activated sludge
30
10
25
15
65
15
30
25
67
*Based on 0.17 Ibs BOD5/capita/day
[Combined sewage and storm drains
-------
TABLE 8 (Continued)
CO
-p.
STP
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendall vi lie, IN
Columbus, IN
Sludge Generated
In 1975
(dry metric tons/year)
642
1120
81
1815
254
178
320
795
2174
Sludge Generated/
Capita/day
(kg)
0.03
0.15
0.04
0.07
0.11
0.05
0.12
0.47
0.45
Sludge
Digestion
Process
2-stage
anaerobic
aerobic
anaerobic
2-stage
anaerobic
anaerobic
2-stage
anaerobic
anaerobic
anaerobic
anaerobic
Average
Solids
Content
(*)
11.4
10.0
5.0
3.0
3.0
10.0
6.5
4.0
5.0
Disposal
Costs
($/dry m ton)
7.98
128.07
26.92
19.58
79.08
22.28
19.04
26.48#
17.65
*City employees, private hauling firm.
-------
cu m/day (1.6 mgd) at Kendallville, Indiana, to a high of 75,700
cu m/day (20 mgd) at Springfield, Missouri.
All of the STP's provided secondary treatment: four
utilized trickling filters, the remaining five providing either
conventional or modified activated sludge processes. Las
Virgenes, California provided aerobic digestion and dewatering
of sludge; the other eight sites simply employed anaerobic
digestion and did not dewater. Three of the sites (Macon,
Georgia; Springfield, Missouri; and Hopkinsville, Kentucky)
employed two-stage anaerobic digestion.
Industrial input to the STP's ranged from an estimated low
of 10 percent at Las Virgenes, California to a high of 67
percent at Columbus, Indiana. Population equivalents ranged
from a low of 12,900 at Frankfort, Indiana to a high of 164,000
at Springfield, Missouri.
SLUDGE
Generation
Based on 1975 STP sludge generation data and average sludge
solids concentrations (either estimated by STP personnel or
calculated from STP or contractor data), the daily generation
of dry sludge solids ranged from a low of 0.03 and 0.04 kg/
capita/day at Macon, Georgia and Wilmington, Ohio, to highs of
0.45 and 0.47 kg/capita/day at Columbus and Kendallville,
Indiana. The latter sites precipitate phosphorus by chemical
addition; the former do not utilize any chemical treatment.
Spreadi ng
The duration of sludge spreading varied from five years at
Chippewa Falls, Wisconsin to seventeen years at Springfield,
Missouri. Annual sludge application rates ranged from 6.8 to
65 m tons/ha at Wilmington, Ohio and Columbus, Indiana
respectively, while total amounts of sludge applied ranged from
66 to 360 m tons/ha at Hopkinsville, Kentucky and Frankfort,
Indiana.
Spreading at two of the sites - Las Virgenes, California
and Chippewa Falls, Wisconsin - stopped as of the 1976 harvest,
the former due to an odor complaint and impending sale, and the
latter following sale of the property to the city for a park.
Disposal
Disposal costs ranged from a low $7.98 to a high $128.07/
dry m ton at Macon, Georgia and Las Virgenes, California,
respectively. Table 9 presents additional STP comparative
information concerning items such as types of transportation
35
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TABLE 9. COMPARATIVE SEWAGE TREATMENT PLANT DATA
Site
Macon, Ga
Las Virgenes, CA
Wilmington, OH
o, Springfield, MO
01
Chippewa Falls,
WI
Hopkinsville, KY
Frankfort, IN
Haul Vehicles
GMC 5 cu yd dump truck
body w/5.2 cu m tank
1971 Chevrolet truck
body modified to hold
two 3 cu yd Dumpsters
1975 Ford 1 ton truck
body w/3.8 cu m tank
1965 Chevrolet truck
body w/11 .4 cu m tank
1967 5 ton Army truck
body w/8.7 cu m tank
1966 1 1/2 ton
Chevrolet truck body
w/3.8 cu m tank
W.W. II Army truck
w/6.6 cu m tank
W.W. II Army truck
w/5.7 cu m tank
Type of Discharge
gravity - splash
pan
dewatered sludge
piled & spread
for field-drying
gravity - splash
plate
gravity - spread-
ing bars
gravity - no
splash plate
gravity - no
splash plate
gravity - no
splash plate
No. of
Disposal
Sites
1
6
1
11
2
4
1
One-way Haul
Distance to
Study Site
(Km)
on STP
property
3
10
0.5
8
0.3
1.5
1975
O&M Cost*
($/dry m ton)
1.09
15.70
3.74
3.13
40.84
3.81
2.05
O&M - Operation and Maintenance
-------
TABLE 9 (continued)
Site
Haul Vehicles
Type of Discharge
No. of
Disposal
Sites
One-way Haul
Distance to
Study Site
1975
O&M Costt
($/dry m ton)
Kendallville, IN#
Columbus, IN**
Private contractor
truck w/9.5 cu m
tank
1965 Dodge truck
body w/9.1 cu m
tank
1975 Marmon truck
body w/9.8 cu m
tank
gravity - no
splash plate
gravity - ten
spreaders
1
(km)
j
0.2
none
3.67
u>
t O&M - Operation and Maintenance
#Sludge disposal contracted to private hauler @ $10/load
**88% of the sludge was delivered to the study site via irrigation pipe
-------
vehicles, haul capacities, one-way distances to the study sites,
and methods of discharge. The final column presents normalized
1975 O&M costs.
PUBLIC AWARENESS
Interviews were conducted at each site with representatives
of the local newspapers, city and/or county health departments,
and various other agencies to assess public awareness and accept-
ance of sludge disposal to nearby agricultural land. The
responses ranged from complete unawareness to a working knowledge
of the practice. Those officials who were cognizant of sludge
spreading supported the program; no opposition was voiced.
Newspaper representatives at seven of the sites were not
aware of any articles, pro or con, relative to sludge spreading,
although two articles which discussed the Phase I and II contrac-
tor visits appeared in the local Frankfort, Indiana newspaper.
Several syndicated column articles dealing with farm and sludge
spreading equipment appeared in the local Chippewa Falls,
Wisconsin newspaper.
Numerous articles pertaining to the Las Virgenes Water
District's effluent disposal program have appeared in the local
newspaper which serves the Las Virgenes Valley in Southern
California. This community expresses a high degree of opposi-
tion to effluent discharge and has been instrumental in thwarting
the Las Virgenes Water District's attempts to obtain a discharge
permit. The editor could not recall publishing any articles
dealing with sludge disposal.
ENVIRONMENTAL PROBLEMS
Table 10 presents a summary of environmental and health-
related items compiled from other interviews. Odor complaints
were reported at three of the sites; two were not considered
serious, and no further action was taken by any of the involved
parties. At Las Virgenes, California, as was mentioned pre-
viously, the complaint was serious enough to stop the spreading
operation at the study site.
Only two of the states (Ohio and Wisconsin) had published
sludge spreading guidelines during the interview phase of this
project (summer 1975), although California, Georgia, Indiana,
and Missouri have documents and drafts in various stages of
development. None of the sites were disposing of sludge under
permit.
No health problems were reported. As can be seen from
Table 11, some of the STP's offered voluntary innoculations;
others offered none. At Las Virgenes, California, Chippewa
Falls, Wisconsin, and Columbus, Indiana, innoculations were
mandatory.
38
-------
TABLE 10. SUMMARY OF REPORTED ENVIRONMENTAL PROBLEMS AND
EXISTING STATE REGULATIONS
Site
Reported
Environmental Problems
Existing State
Landspreading Regulations
00
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, VII
Hopklnsville, KY
Frankfort, IN
Kendallvllle, IN
None
Odor complaint has stopped spreading
at study site* Other STP disposal
sites were not affected.
None
Some odor complaints - none serious
None
None
One odor complaint - not serious
One complaint about possible
"runoff" contamination - complaint
not investigated, and dismissed by
County Sanitarian
None
In working draft stage as of 2/1/76
Bulletin #598, "Ohio Guide for Land
Application of Sewage Sludge," revised
May 1976
In development stage
Technical Bulletin #88, "Guidelines
for the Application of Wastewater
Sludge to Agricultural Land 1n
Wisconsin," 1975
None
In development stage
In development stage
Columbus, IN
None
In development stage
-------
TABLE 11. STP EMPLOYEE INNOCULATION PROGRAM
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendall villa, IN
Columbus, IN
Voluntary - influenza, tetanus, typhoid
Mandatory - typhoid, tetanus, polio
None
Voluntary - various innoculations offered
Mandatory - typhoid, tetanus, polio
None
None
None
Mandatory - typhoid, tetanus, polio
40
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CHAPTER VII
FIELD SAMPLING PROGRAM
SCOPE AND OBJECTIVES
The Phase I sampling program provided preliminary data
sufficient to select the nine case study sites; the program for
Phase II sampling was designed to provide an expanded data base,
so that the environmental impact of the sludge landspreading at
each site could be properly assessed, conclusions drawn, and
recommendations made. A detailed sampling program was developed
and executed for the chemical, physical, and microbiological
examination of sludges, soils, and plants at each site.
SLUDGE
The sampling at each sewage treatment plant was performed
as follows:
At six-hour intervals, five prepared 1-t plastic
"cubitainers" were filled with grab samples of combined
primary and secondary sludge (before they entered the
digester). These samples were labeled "raw-frozen."
Another five cubitainers were filled, over a 24-hour
period, with grab samples of stabilized sludge. These
samples were taken when the sludge entered the tank
truck for field distribution and were labeled "stabil-
ized-frozen."
t Eight of the cubitainers were placed in a freezer and
frozen for a minimum of 16 hr.
One cubitainer sample each, of the raw and stabilized
sludge taken from the same sampling points, was preserved
by chilling in a refrigerator at approximately 2 to 4°C.
These samples were labeled "raw-chilled" and "stabilized-
chilled," respectively-
Each of the cubitainers was then wrapped in several layers
of newspaper, placed in a styrofoam-1ined cardboard box to
which three or four frozen "blue-ice" packets had been added
(to maintain sample integrity) and shipped air freight to the
contractor. Upon arrival, all samples were immediately trans-
ferred to either chilled or frozen storage.
41
-------
Each set of four frozen "raw" grab samples was allowed to
thaw at 2 to 4°C and then composited in four 1-1 beakers which
had been acid-cleaned in the same manner as the cubitainers;
these were stirred thoroughly and poured back into the original
cubitainers, each of which then held a composite. This pro-
cedure was repeated for the "stabilized-frozen" sludge, and all
eight samples then returned to the freezer prior to shipment to
the contractor.
Four cubitainers (one each of chilled and frozen, raw and
stabilized sludge) were analyzed for:
Helminths,
Protozoans,
Total aerobes,
Salmonella,
Shigella,
Fecal coliforms, and
Fecal streptococci.
The remaining frozen stabilized samples were analyzed for:
pH Arsenic (As)
Dieldrin Cadmium (Cd)
DDT Calcium (Ca)
PCB's Chromium (Cr)
Moisture content Cobalt (Co)
Volatile solids (V.S.) Copper (Cu)
Chlorides (Cl) Iron (Fe)
Sulfates (S04) Lead (Pb)
Organic-nitrogen Magnesium (Mg)
Nitrate-nitrogen (NC^-N) Manganese (Mn)
Ammonia-nitrogen (NH4-N) Mercury (Hg)
Boron (B) Molybdenum (Mo)
Potassium (K) Nickel (Ni)
Phosphorus (P) Selenium (Se)
Sodium (Na) Silver (Ag)
As previously indicated, 1-t plastic "cubitainers" were
used for the sludge sampling. The cubitainers and caps were
prepared by:
Rinsing with hot water,
Allowing to cool,
Removing all traces of contaminants with a reagent
grade hydrochloric acid diluted 1:1 with distilled
water,
Rinsing several times with cold tap water,
42
-------
Rinsing several more times with ultra pure (18 megohm)
water,
Collapsing the cubitainers, and
Securing the caps tightly.
SOIL SAMPLES
Commercially available 1- or 2-gal polyethylene bags
were used for soil containers; all samples were double-bagged.
At each study site, both the treated and control plots
were divided into five rectangular sub-plots of approximately
equal area; the Las Virgenes control plot was divided into only
three sections because of its shape and size.
Surface Soils
Surface soil samples were taken to a depth ranging from
15 to 30 cm (6 to 12 in); this corresponds to the plow depth or
"cultivation zone" (Ap) defined by the farmer. Twenty to forty
soil corings were taken from each of the five sections in both
the treated and control plots at each site. A 2.5 cm (1 in)
diameter stainless steel split tube sampler was used. The
sampling was performed in such a manner that cores were drawn
from all areas within each section, except at Las Virgines,
California, where samples were withdrawn on the section line
as opposed to within an area. The number of cores withdrawn
varied directly with the depth of the Ap zone; the deeper the
Ap zone, the fewer the corings.
Any miscellaneous non-soil debris was removed from each
coring prior to the soil being placed in the sample bag; each
section was ultimately represented by approximately 2.3 kg
(5 Ibs) of soil samples.
The soil sample representing each section was analyzed for
total Cd, Cu, Ni, and In.
A composite sample, consisting of a representative amount
from each of the five section samples, was analyzed for:
pH PCB's
Moisture content Total Cd, Cu, Ni, Pb, and Zn
N03-N DTPA-extractable Cd, Cu, Ni, and Zn
NH4-N Total aerobes
OrganicN Salmonella
Organic carbon Shigella
Cation exchange capacity Fecal coliforms
Textural composition Fecal streptococci
43
-------
DDT Helminths
Dieldrin Protozoans
One bulk sample of approximately 115 kg (250 Ibs) of soil
from the Ap zone of both the treated and control plots of each
site was sent to the EPA Municipal Environmental Research
Laboratory, Cincinnati, Ohio, for greenhouse studies.
Subsurface Soil
Subsurface soils were considered to be those below the Ap
zone; samples were obtained from treated and control plots at
all nine sites. A 7.6 cm (3 in) dia stainless steel bucket
auger was used to obtain corings except at Kendallvil1e,
Indiana, where a 5.1 cm (2 in) dia stainless steel pneumatic
coring tool mounted on a vehicle was used.
Discussions between the farmer, local SCS representatives,
and the contractor's soil consultant, with the aid of soil
survey maps, defined the layers (horizons) of the samples.
The A horizon typically was the zone between 20 and 40 cm
(8 and 16 in), the B horizon between 40 and 61 cm (16 and 24 in),
the C horizon between 61 and 91 cm (34 and 36 in), and the D
horizon between 91 and 122 cm (36 and 48 in). However, at
Kendal1vil1e, Indiana, the A horizon was between 20 and 30 cm
(8 and 12 in), and the B horizon between 30 and 61 cm (12 and 24
in). At Springfield, Missouri, the C horizon was between 61 and
81 cm (24 and 32 in), the D horizon between 81 and 122 cm (32
and 48 in); and at Las Virgenes, California, the two lowest
horizons, between 61 and 91 cm (24 and 36 in) and 91 and 122 cm
(36 and 48 in), were labeled B and C.
Samples were withdrawn from the four horizons in each of
the five subplots at all sites; each sample was placed in a bag
specific for the soil horizon and depth and labeled horizon A,
B, C, or D. Thus, each plot was represented by twenty subsur-
face samples, one from each horizon of each section. Total
sample size for each composited horizon was approximately 2.5
kg (5 Ibs).
The uppermost portion of soil, that from the Ap zone, as
well as miscellaneous non-related debris sloughed from the sides
of the hole or the surface, was discarded from the auger before
the samples were bagged.
Small subsamples were withdrawn in the field from each of
the surfaces and four horizon subsurface samples to form plot
composites for both the treated and control plots. These were
immediately placed in refrigerated storage (2 to 4°C) and marked
for bacteriological and parasite examinations; the remaining
samples were stored under ambient conditions.
44
-------
Each of the chilled soil samples was boxed in a styrofoam-
lined cardboard container to which three or four frozen "blue-
ice" packets had been added; all of the soil samples were then
sent via air freight to the contractor. The chilled samples were
immediately transferred to 2 to 4°C storage.
The unchilled soil samples were unpacked and spread in
discrete piles on a clean, tarped floor. As each sample bag
was opened, a small subsample was withdrawn into a whirl-pak
bag to determine field moisture. The samples were then air
dried from 7 to 14 days, depending on the original moisture
level. Each sample was then ground thoroughly (to less than
2,mm) in an Her Disk Pulverizer.
The series of cores taken from each horizon of each section
were analyzed individually for total Cd, Cu, Ni, and In.
Four composite samples representing the four distinct
depths throughout all five sections of each plot were prepared
from the above samples and analyzed for:
pH Total aerobes
Moisture content Salmonella
N03-N Shigella
NH4-N Fecal coliforms
Organic N Fecal streptococci
Organic carbon Helminths
Cation exchange capacity Protozoans
Textural composition
as well as Total Cd, Cu, Ni, Zn, and Pb, and for DTPA extractable
Cd, Cu, Ni, and Zn.
All of the analyses were performed for treated and control
plots.
PLANT SAMPLES
Plant samples were taken from treated and control plots of
all nine sites. Care was taken to ensure that the portion of
the plant sampled was not contaminated with dried or adhering
sludge. This was performed by sampling aerial portions of the
various plants and careful visual inspection.
Wheat and grasses were sampled by shearing and retaining
the aerial portion; approximately 10 to 30 bunches of grasses
and wheat with 10 to 100 individual stalks or blades were taken
in each section. Since several plots contained more than one
type of grass, the desired plants were hand sorted from the
others. Corn and soybean leaves were handpicked. The crops at
Frankfort and Columbus, Indiana- and Chippewa Falls, Wisconsin
produced edible grains of wheat, corn and soybeans, respectively;
45
-------
these were sampled just before harvesting, the wheat with
of shears, the corn by hand picking, and the soybeans with
rnmhino
a pair
combi ne.
Samples were taken from the entire area of each section
except as noted in Volume III.
Each of the section samples resulted in approximately 2 kg
(4.5 Ibs) of plant tissue. Samples were double-bagged In 1- or
2-gal polyethylene bags which were refrigerated at 2 to 4°C until
shipment. All samples were placed in styrofoam-1ined cardboard
boxes to which three or four frozen "blue-ice" packets had been
added and were air freighted to the contractor, where they were
again refrigerated at 2 to 4°C. The edible grains were shipped
under ambient conditions.
Two composites of leaves were prepared for each plot by
mixing equal weight portions. One of the composites was
analyzed for:
Organic-N
DDT
D i e 1 d r i n
PCB's
Total Cd, Cu, Ni, Zn, and Pb.
The other composite was analyzed for:
Total aerobes,
Salmonella,
Shigella,
Fecal coliforms,
Fecal streptococci,
Helminths, and
Protozoans.
The edible grain samples were composited as above, except
for the wheat which was air-dried for seven days and threshed
before compositing. The composites were chemically analyzed for
total Cd, Cu, Ni, Zn and Pb. Bacteriological and parasite
examinations were not made of the edible grains.
46
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CHAPTER VIII
DATA ANALYSIS
INTRODUCTION
The data analysis is presented in two sections as follows:
Section I - Individual Study Site Analyses.
The sludge, soil, plant, and microbiological findings
from the field sampling program and the information
gathered at each study site are summarized and analyzed
in this section. The raw data supporting the analyses
are presented in Volume II for each study site.
Section II - General Evaluation.
The site data are collectively examined and compared to
data obtained during related studies in this section.
Observations and conclusions are drawn within the frame-
work of the study constraints.
The following were utilized in completing the data analysis:
t Reference is made to "reported ranges" and "median"
concentration values when discussing sludge characteris-
tics. These data are from Sommers (1977) and Furr,
e_t a_l_. (1976), and are presented in Table 12, along
with sludge analytical data from all nine case study
sites.
Calculation of available N in the sludges was based on
an assumed annual availability of 50 percent of the
ammonia-N and 20 percent of the organic-N. It was
assumed that organic-N was unavailable in the following
year. NO_3-N levels were so low that they were not con-
sidered in the calculations.
0 The current (1977) fertilizer equivalent value of N was
assumed at $0.44/kg.
The plant availability .of sludge-borne P is not precisely
known. Therefore, it was assumed that 100 percent of
the sludge P was plant available.
47
-------
TABLE 12. CHEMICAL COMPOSITION OF STABILIZED SLUDGES FROM ALL STUDY SITES
Parameter*
Vol. Solids (%)
Total N
N03-N
NH4-N (%)
Org-N (%)
P (%)
K (35)
Na («)
Ca (%)
Mg (%)
so4/ N
Cl (%)
* A9
c» As
B
Cd
Cr
Co
Cu
Fe
Hg
Mn
Mo
Ni
Pb
Se
Zn
HoO
PR
Macon,
Georgia
36.9
4.55
7.80
1.10
3.45
1.23
0.22
0.39
2.78
1.21
348
0.10
1.58
2.21
72
11.9
1,130.
21.3
960.
23,600
16.4
600.
14.5
140.
610.
13.7
1,770.
91.3
7.50
Las Virgenes,
California
74.7
4.84
0.41
0.32
4.52
1.71
0.16
0.20
2.65
0.49
81.7
0.15
3.45
4.13
71.6
11.1
150
6.39
950.
6,920
7.27
480.
10.2
50
40
7.02
1,350
85.6
6.60
Wilmington,
Ohio
52.4
3.81
13.7
1.01
2.80
3.55
0.21
0.20
3.14
0.92
105
0.28
2.42
1.13
37.5
11.2
2,240
6.96
410.
13,600
1.93
250.
45.5
30.
1,110.
4.23
45,800
95.8
7.80
Springfield,
Missouri
59.2
8.48
51.4
4.18
4.30
1.74
0.54
0.80
5.92
0.63
111
0.50
0.95
6.21
40.5
56.1
2,430,
9.07
820
13,500
10.6
450.
43.4
300
150
8.17
3,310
98.3
8.30
Chippewa Falls,
Wisconsin
56.4
4.58
13.0
2.12
2.46
1.34
0.22
0.69
1.39
0.52
66.0
1.09
5.92
2.52
42.5
7.03
1,270.
6.17
1,370
13,300
24.1
220
6.60
20.
100
7.60
1,190
97.5
7.80
-------
TABLE 12 (continued)
10
Parameter*
Vol. Solids (%)
Total N
NOs-N
NH4-N (%)
Org-N (%)
P («)
K (%)
Na (%)
Ca (%)
Mg (%)
S04
Cl (%)
Ag
As
B
Cd
Cr
Co
Cu
Fe
Hg
Mn
Mo
Ni
Pb
Se
In
H20
pH
Hopkinsville,
Kentucky
41.1
2.37
10.2
0.54
1.83
1.56
0.13
0.20
6.25
0.36
10.0
0.03
1.16
1.14
32.1
7.60
380
9.68
550
7,460
9.82
200
11.1
60
90
6.36
1,470
87.8
7.5
Frankfort,
Indiana
48.3
3.04
13.4
0.74
2.30
1.57
0.22
0.62
4.76
0.55
10.0
0.12
1.95
3.06
43.6
1,500
3,990
16.2
7,140
21,400
4.41
320
6.77
500
250
5.68
2,150
93.8
7.3
Kendallville,
Indiana
36.1
1.76
4.05
0.28
1.48
1.41
0.53
0.65
2.58
1.23
8.60
0.67
10.2
5.11
43.8
50.0
2,010
24.9
730
48,100
3.08
9,870
7.54
80
7,480
17.2
7,190
91.0
7.5
Columbus,
Indiana
55.0
3.57
60.0
1.27
2.30
1.33
0.32
0.61
2.26
0.59
118
0.32
1.23
2.19
38.7
5.70
410
24.1
390
10,200
2.60
470
21.1
160
100
6.64
740
96.0
8.2
Comparative Sludge Datat
Range
0.5-7.6
2-4,900
0.005-6.76
< 0.1-10.8
< 0.1-14.3
0.02-2.64
0.01-3.07
0.1-25.0
0.03-1.97
0.6-1.1
0.05-1.02**
5-150**
6-230
4-760
3-3,410
10-99,000
1-18
84-10,400
< 1,000-153,000
0.5-10,600
18-7,100
5-39
2-3,520
13-19,700
1.7-8.7t
101-27,800
Median
4.8
140
0.09#
3.21
2.3
0.3
0.24
3.9
0.45
0.8
0.29**
20f
10
33
16
890
4.0
850
11,000
5.0
260
30
82
500
2.7t
1,740
-------
TABLE 12. (continued)
*A11 units in ug/g (oven-dry weight basis) unless otherwise noted.
tDewatered and dried sludges included.
^Results from analyses of more than 250 sewage sludge samples from approximately 150 STP's in the
north central and eastern regions, U.S. (Sommers, 1977). The S values are for total S, not $04.
**Data of 42 sewage sludges from locations in England and Wales (Berrow and Webber, 1972).
of sewage sludges from 16 American cities (Furr, et al., 1976).
in
O
-------
The current fertilizer equivalent value of P was
assumed at $1.00/kg.
t The potential for groundwater contamination was based
on a combination of the chemical and physical properties
of the sludges and soils to a depth of 122 cm. The
analyses were based only on the potential migrations of
Cd, Cu, N, Zn, and Pb in the soil profile.
51
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SECTION I - INDIVIDUAL STUDY SITE ANALYSES
Macon, Georgia
Sludge Characteristics--
Table 12 shows a comparison of Macon sludge composition
with Sommers' data for 150 STP's.
Nitrogen and phosphorusTotal N (4.55 percent), organic-N
(3.45 percent), NOo (7.8/uj/g), and NH^-N (.1.1 percent) from the
Macon STP were within the ranges previously reported for sludges.
The Macon STP method of spreading liquid sludge onto the
surface without immediate incorporation into the soil probably
results in a substantial loss of ammonia to the atmosphere.
Assuming that 20 percent of the organic-N and 50 percent of the
NH4-N is available to plants, 1 m ton of Macon sludge would
contain 12.4 kg of available N and have a value of $5.46 (at
current fertilizer prices).
The P concentration (1.23 percent) was somewhat less than
the reported median concentration (2.3 percent). How much of
the sludge-borne P was available to plants is not precisely
known, since the Macon sludge contained considerable Fe wh'ich
can tie up P as an insoluble complex. If, however, all of the
P in the sludge is considered equivalent to commercial sources
of P, 1 m ton of the Macon sludge would supply the equivalent
of 12.3 kg and have a value of $12.30. In terms of both N and
P, the sludge would have a value of $17.76/m ton.
The annual estimated application rate of the Macon STP
sludge was approximately 28 m tons/ha, equivalent to 347 kg/ha
of available N and 344 kg/ha of total P, and was in excess of
yearly plant requirements. However, the availability of both
N and P is probably considerably less than the calculated
figures due to various factors:
Volatilization of NH3 from surface spreading,
9 Inhibition of nitrification by low soil pH, and
Fixation of P by Al and Fe compounds.
Other elements All of the elements analyzed were within
the normal concentration ranges reported for sludges. Mg and Co,
however, were considerably higher than the median; the high Mg
content in the sludge was particularly beneficial to both soil
and crops at the Macon site, since most soils in the south-
eastern U.S. are acid, sandy, and deficient in Mg. The trace
elements B, Fe, Hg, Ni, and Se, too, were present at concentra-
tions higher than the median values customarily reported in the
52
-------
literature. Conversely, Ag, As, Cd, Cu, and Zn were either less
than or comparable to normal median concentrations. Selenium,
in particular, was of possible concern at 13.7 yg/g, when
compared to the median value of 2.7 yg/g. The strongly acidic,
sandy soil has never been limed. Consequently, the trace
elements, in concentrations which would not normally cause
problems if applied to properly managed soils, would be likely
to cause plant phytoxicity or groundwater contamination.
Soil Analysis--
Total metals Table 13 presents total and DTPA-extractable
results for treated and control surface and subsurface soil
samples. The data show that the treated surface soil was
greatly enriched with Cd, Cu, Ni, Zn, and Pb, and the concentra-
tions of Cd, Cu, Zn, and Pb in the treated surface soil were
greater than soil concentrations normally reported. However, as noted
under sludge characteristics, the sludge metal levels were
either below or at comparable reported median values, which
suggests that repeated applications of a sludge over a long time
may result in a significant accumulation of metals in the
surface soil.
The data also indicate downward migration of Cd, Cu, and
especially Zn in the treated plot; Cd and Cu moved into the
20-to 46-cm depth layer, while Zn migrated down to 122 cm. This
movement of the heavy metals was attributed to the high acidity
and coarse texture of the soil and high precipitation in the
area.
The metal concentrations at the 91- to 122-cm depth were
considerably higher than the other subsurface layers, in both
treated and control plots, due in part to the abrupt change from
sand to clay at this depth.
Selenium values for surface and subsurface treated soil
samples ranged from 0.26 to 1.2 yg/g. Control samples were all
reported as 0.016 yg/g-
DTPA-extractable metals--DTPA-extractable metal concentra-
tions (Cd, Cu~, NT",and Zn) evidenced trends :simil ar to those
observed for total metals. There was some indication of movement
of the metals beyond the depth of incorporation (20 cm) and
significant downward migration of Zn. The DTPA-extractable Cu
and Zn levels were quite high, while the Cu level was below
phytotoxic concentration. Based on the NCR 118 (1976) report,
the Zn level was sufficiently elevated to be in the phytotoxic
range for some plant species.
The percent of total metals extracted by DTPA was higher
for the treated soils than for the control, and also higher for
the surface soil than for subsurface layers. These observations
53
-------
en
-P*
TABLE 13. CONCENTRATIONS OF TOTAL AND DTPA-EXTRACTABLE METALS IN
COMPOSITE SURFACE AND SUBSURFACE SAMPLES
FROM MACON, GEORGIA*
Soil
Depth
- cm -
Treated:
0-20
20-46
46-61
61-91
91-122
Control :
0-20
20-46
46-61
61-91
91-122
-Totalt
Cd
5.89
0.96
0.47
0.33
0.99
0.76
0.63
0.51
0.40
0.95
Cu
-
267
13.3
10.1
6.93
19.6
11.9
10.5
6.0
6.56
20.4
Ni
- wg/g
67.6
17.1
9.44
12.5
24.4
19.1
13.6
12.3
13.4
24.0
Zn
Pb
Cd
DTPA-Extractable
Cu
Ni
Zn
- - vg/g - -
475
80.4
39.0
27.5
88.5
27.7
25.1
15.5
15.3
52.4
325
35.4
19.4
13.9
49.6
35.0
28.5
16.8
13.1
38.9
1. 42(24 )#
0.22(23)
0.10(20)
0.06(18)
0.10(10)
0.08(10.5)*
0.03(4.8)
0.04(8.0)
0.06(15)
0.08(8)
64.
4.
1.
1.
2.
1.
0.
0.
0.
3.
3 (24)
10(31)
63(16)
20(17.3)
40(12)
23(10.4)
74(7)
62(10.3)
72(11)
31(1.6)
13.7 (20)
2.55(15)
0.94(10)
0.66(5.3)
1.70(7)
0.72(3.8)
0.40(3)
0.27(2.2)
0.29(2.2)
0.55(2.3)
269
37.
16.
9.
27.
1.
0.
0.
1.
1.
(56.6)
80(47)
40(42)
59(35)
60(31)
14(4.1)
87(3.5)
59(3.8)
03(6.8)
02(2.0)
*0ven-dry weight basis.
tHN03-HC!04 digestion.
^Percent of total concentration.
-------
suggest (1) a relationship between organic matter content and
solubility of metals in DTPA, and (2) that sludge-borne metals
are more readily extracted by DTPA than metals occurring
naturally in soils. The high percentages of Zn extracted by
DTPA in the treated plot (31 to 57 percent) strongly suggest
that the movement of Zn in the treated plot is real, and the
Zn occurring at various depths apparently is sludge-borne.
Plant Analyses--
Total metal (Cd, Cu, Ni, Zn, and Pb) concentrations in the
treated plot cheatgrass and in the control plot oats are given
in Table 14.
The Cu and Ni concentrations in the cheatgrass forage were
relatively high, but not high enough to cause health problems to
livestock (CAST, 1976). However, the concentration of Zn in
the cheatgrass was sufficiently high so that most agronomic crops
would be expected to suffer phytotoxic effects. Heavy metal
uptake by any future crop"at the Macon sludge-spreading site can
be expected, because of the soil pH and texture.
The data exhibit excellent agreement between composite
metal concentrations and the mean concentrations of the five
sections constituting the composite. Selenium analysis on treated
and control plant composites showed levels of <0.016 yg/g.
Microbiology--
Stabilized sludge samples taken in April 1976 contained
four species of intestinal parasite ova, one of human and three
of animal origin. Salmonel1 a sp. or Shige1 la sp. were not found
in the raw or stabilized sludge. This is somewhat surprising
because the poultry processing plant which discharges wastewater
to the system should contain a high titre of Salmonel1 a sp.
organisms. (Poultry , and chicken in particular, are a known
reservoir of salmonella-type organisms.) The fecal coliform (FC)
and fecal streptococci (FS) groups of organisms in both the raw
and digested sludge were represented in slightly anomalous ratios
of concentration, as compared to the other eight sludges studied.
No reason is apparent for this difference.
The soils in the treated and control plots had roughly the
same content of FC and FS organisms. As with o^her test sites
where these data correspond, homeostatic conditions in the soil
are the probable explanation.
The soil sample from the treated plot, at a depth of 20 cm,
contained Ascari s lumbricoides ova in low concentration. The
viability of the ova could not be conclusively determined
because of the low concentration and difficulty in embryonating
55
-------
TABLE 14. METAL CONCENTRATIONS IN CHEATGRASS AND OATS
FROM MACON, GEORGIA*
Sample
Treated:
Composite
Section 1
Section 2
01 Section 3
CTl
Section 4
Section 5
Mean
Std. Dev.
Control :
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Cd
0.77
0.84
0.77
0.58
0.73
0.62
0.71
0.11
Cu
18.5
30.0
19.8
24.1
17.2
18.8
22.0
5.16
Cheatgrass
Ni
- - yg/g -
16.4
17.0
16.7
15.1
21.6
16.6
17.4
2.46
Zn
-
375
455
404
392
325
341
383
52
Pbt Cd
4.86
0.31
0.36
0.22
0.31
0.39
0.29
0.31
0.07
Cu
-
5.93
6.02
5.69
6.34
5.31
4.70
5.61
0.64
Oats
Ni
- yg/g -
3.90
3.50
3.28
3.83
3.70
3.83
3.63
0.24
Zn Pbt
-
30.8 4.38
31.5
28.0
33.3
31.3
31.9
31.2
1.95
* Oven-dry weight basis.
tLead was analyzed on composite only.
-------
the low numbers of immature eggs. Therefore, the possibility
that the ova were viable exists.
The cheatgrass in the treated plot and oats from the
control plot were both negative for FC, but did show the presence
of FS in low numbers. The ratio of FC/FS concentrations on the
plant tissue follow roughly the low FC/FS ratios exhibited by
the raw and stabilized sludge. Since there is no indication in
the history of the site of livestock grazing, that influence must
be discounted.
Sludge, Soils, and Plants Conclusions--
t Although the sludge from the Macon STP is acceptable for
agricultural utilization, , . T" .r ---iy
excessive annual sludge applications, site soii proper-
ties, depth to groundwater, and high rainfall have
created conditions that greatly enhance plant uptake
and movement of heavy metals (e.g., Cu and Zn) to lower
soil depths.
t Such factors as low soil pH, coarse soil texture, and
high precipitation in the area all favor the downward
movement of heavy metals in addition to other easily
leached anions. The soil data indicate some movement
of Cd, Cu, Ni, and Zn beyond the depth of incorporation.
There is a good likelihood that Zn is already entering
the groundwater, and the possibility of groundwater
contamination from Zn or anions such as NOs, Cl, $04,
etc., is a real i ty.
The sludge-spreading operation has resulted in adverse
effects on crops, soil, and probably groundwater quality.
Selenium has accumulated in the treated surface and
subsurface soils but was not detected in the plant
tissues. This was consistent with results reported by
others (Cast, 1976).
Las Virgenes, California
Sludge Characteristics--
Nitrogen and phosphorus As shown on Table 12, concentra-
tions of total N (_4.84 percent) , organic N C4.52 percent!,
NH4-N (0.32 percent), and NC^-N CO.41 ug/g), were witKin the
ranges previously reported.
The spreading and drying of the sludge prior to application
probably resulted in almost complete loss of the NH4-N. Based
57
-------
on previous assumptions, 1 m ton of the sludge would supply the
equivalent of 10.6 kg of available N, with a current value of
$4.66/m ton.
Phosphorus concentration (1.71 percent) was slightly below
the reported median of 2.3 percent. If all of the P in the
sludge is considered equivalent to commercial sources, 1 m ton
of sludge would supply the equivalent of 17.1 kg P and have a
value of $17.10/m ton.
In terms of N and P, the sludge would have a fertilizer
value of $21.76/m ton. The annual estimated application rate
of Las Virgenes sludge was approximately 50 m tons/ha, equivalent
to 530 kg/ha of available N and 855 kg/ha of total P, in excess
of plant requirements. The nitrogen equivalent was possibly
less than stated, depending on NH3 losses from the spreading
operation.
Other elements Concentrations of all of the elements were
within the normal ranges reported for sludges, Cd slightly less,
B, Co, and Cu slightly greater, and Hg (49 yg/g) and Se (7 yg/g)
considerably greater than median concentrations reported.
Effluent characteristicsIrrigation water at the study site
was supplied through reclaimed secondary effluent from the STP-
The quantities of metals N and P applied to the test plot at
Las Virgenes were consequently influenced by the amount of
secondary effluent irrigation water used. Records of the quanti-
ties of effluent water applied were not kept; an estimate based
upon normal irrigation practices for the region (1.2 m irrigation
water per year) is presented in Table 15.
TABLE 15. NITROGEN, PHOSPHORUS, AND METALS APPLIED IN SEWAGE
TREATMENT PLANT EFFLUENT AND SLUDGE - LAS VIRGENES, CALIFORNIA
Element
N
P
Cd
Cu
Ni
Pb
Zn
Total Amount Applied
in Effluent*
kg/ha
1,010
1,800
0.42
3.0
2.2
3.0
6.6
Total Amount Applied
in Sludget
kg /ha
6,920
2,620
1.69
145
7.6
6.1
207
Total
Applied
kg/ha
7,930
4,410
2.1
148
9.8
9.1
214
*Assuming effluent has been applied at the rate of 1.2 m/yr for five years'
and the composition of the effluent is as given in Table 16, Volume II.
tAssuming 153 total m tons/ha applied and the composition of the sludge is
as given in Table 12.
58
-------
The analyses showed that the use of effluent water had made a
substantial contribution to N, P, Cd, Ni, and Pb loadings. In
terms of the total mass loading estimate (from both sludge and
effluent), the effluent had contributed about 15 percent of the
total N applied, 41 percent of the total P, 20 percent of the
total Cd, 29 percent of the total Ni, and 33 percent of the
total Pb. The amounts of Cu and Zn applied in the form of
effluent were very small in comparison to amounts applied in
the form of sludge.
Soil Analysis--
Total metals--Table 16 presents total and DTPA-extractable
metal analyses of treated and control surface and subsurface
soils. Except for Cd, the total soil metal concentrations for
both treated and control plots were in the range considered
normal. However, Cu and Zn concentrations in the surface 30 cm
of treated soil were greater than those of the control plot, a
result of these metals being added in the form of sludge.
Total metal concentration profiles for both the treated and
control soil columns, except for Cu and Zn in the treated surface
soils, were fairly consistent and almost identical. The rela-
tively constant metal concentrations throughout the soil column
confirmed that the sludge applied metals had not migrated in
measurable amounts below the depth of incorporation.
Total treated and control plot soil Cd concentrations were
approximately the same at all depths and unusually high (3 to 4
yg/g). However, Burau, ejt a]_. , 1973, reported that soil series
in California similar to those sampled at Las Virgenes have Cd
concentrations as great, or even greater. It is reasonable,
therefore, to conclude that the high Cd levels observed in the
soil are of natural origin and not derived from sludge disposal
or recycling operations.
DTPA-extractable metals--The DTPA data tended to confirm
the interpretation of the data presented for total analyses.
DTPA data showed accumulations of both Cu and Zn in the surface
soil of the treated plot and further indicated that the metals
applied in the form of sludge had remained in the surface layer
and not migrated to lower depths.
The percent of total metals extracted by DTPA varied with
soil depth. Again, the sludge-borne metals in the surface soil
were more readily extracted than were the metals occurring
naturally in the surface soil of the control plot. More Cd and
Cu than Ni or Zn were extracted by DTPA. Analyses of composite
samples of the surface soil correspond closely to the mean of
each of the samples which made up the composite.
59
-------
TABLE 16. CONCENTRATIONS OF TOTAL AND DTPA-EXTRACTABLE METALS
COMPOSITE SURFACE AND SUBSURFACE SAMPLES
FROM LAS VIRGENES, CALIFORNIA*
IN
Soil
Depth
- cm -
Treated:
0-30
31-61
61-91
91-122
Control :
0-30
30-61
61-91
91-122
Totalt
Cd
3.58
3.79
3.41
3.53
3.77
3.75
3.22
4.11
Cu
45.4
29.1
28.5
28.5
27.7
27.6
28.0
28.1
Ni
- vg/g
52.9
50.3
49.5
50.2
48.0
50.5
50.2
52.8
Zn
120
93.4
93.8
90.7
98.1
94.2
90.2
90.9
Pb
21.7
19.3
19.0
18.7
19.9
19.7
19.9
20.6
1
1
1
1
1
1
1
1
Cd
.48(41)#
.21(32)
.23(36)
.35(38)
.37(36)*
.37(37)
.53(48)
.65(40)
DTPA-Extractable
Cu
Ni
- - yg/9 - -
5.41(12) 2.51(4.8)
2.06(7.1)
2.47(8.7)
2.89(10)
1.69(6.1)
2.31(8.4)
2.50(8.9)
2.37(8.4)
2.30(4.6)
2.99(6.0)
3.07(6.1)
1.45(3.0)
2.37(4.7)
3.22(6.4)
3.15(6.0)
Zn
8.
0.
0.
0.
1.
0.
0.
0.
12(6.8)
42(0.5)
31(0.3)
80(0.4)
01(1.0)
89(0.9)
85(0.9)
60(0.7)
* Oven-dry weight basis.
tHN03-HC104 digestion.
# Percent of total concentration.
-------
Plant Analyses--
As is apparent from Table 17,which presents total metal
analysis of the -ryegrass from the treated and control plots,
the concentrations of Cu, Ni, and Zn were in the normal range
for this type of forage (Chapman, 1966). Concentrations of Cd
were slightly greater, and Pb considerably greater, than those
usually observed. The slightly elevated concentrations of Cd
were probably a result of the naturally high concentration of
Cd in the soil. Since the treated plot contained less Cd than
the control plot, it appears that application of sludge has not
been responsible for the higher Cd levels in the rye grass.
Concentrations of Cu and Zn in rye grass for the control
plot were not significantly different from those of the treated
plot. Nickel in the treated plot was low for the foliage, but
greater than its concentration in the control plot.
Microbiology--
No intestinal parasite ova were found in any of the sludge
samples. However, it should not be inferred from this finding,
or other sites with negative results, that no parasite ova are
associated with waste sludge, since the absence of intestinal
parasite ova in sludge as reported by Aiba, Sudo, and Liebman
(Aiba, e_t aj_. 1965, Liebman 1965) is atypical. The high economic
levels and health standards of inhabitants of the area tributary
to the Tapia Water Reclamation Plant may suggest a low or
negligible incidence of helminth infection. The absence of
salmonella or shigella species was not unexpected in view of
the small sample base and the relatively low numbers of these
organisms usually found in sewage solids (Kenner, 1972). How-
ever, the absence of fecal coliforms in the August 4, 1976, raw
sludge sample was not readily explainable; the FC population in
the stabilized sludge for the same date was in excess of seven
logs greater. One possible explanation could be the aerobic
digestion process of the Tapia plant.
The soils and associated microflora in the treated and
control plot showed some evidence of being homeostatic. The
positive detection of fecal organisms in the treated plot may
have resulted from the incidental pasturing of livestock (beef
cattle) in the field,subsequent to rye grass harvest. Further
support to this thesis was provided by the preponderance of FS
organisms in the soil (Mara, 1977).
Both the treated and control plots of rye grass also were
positive for FS. The control plot plant specimens, too,
appeared to be influenced by livestock grazing.
61
-------
TABLE 17. METAL CONCENTRATIONS IN .RYEGRASS
FROM LAS VIRGENES, CALIFORNIA*
ro
Sample
Treated:
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Control :
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std, Dev.
Cd
0.72
0.44
0.52
0.89
0.78
0.72
0.67
0.19
1.56
1.79
1.11
1.34
1.41
0.35
Cu
-
12.5
13.9
9.53
13.3
10.4
9.68
11.4
2.08
11.5
11.1
10.3
10.2
10.5
0.49
Leaves
Ni
- ug/g -
7.80
9.30
10.50
8.48
7.38
9.37
9.01
1.16
4.25
5.43
5.69
4.13
5.08
0.84
Grains
Zn Pbt Cd Cu Ni Zn Pb
- - yg/9 - -
60.0 14.6
60.4
51.0
77.0
58.6
45.5
58.5
12.0
70.0 8.40
71.3
57.7
54.2
61.1
9.03
^Oven-dry weight basis.
tLead was analyzed on composite only.
-------
Sludge, Soils, and Plants Conclusions
The use of sludge as a
no impact on uptake of
tested in plants.
soil amendment has had little or
those trace metal elements
Total and DTPA-extractable metal analyses suggest that
metals have not moved beyond the depth of incorporation,
Large amounts of nitrogen, considerably in excess of
those needed by the crop, have been applied via irriga-
tion waters. It is possible that groundwater N03-N
contamination may occur, if these large N applications
conti nue.
The possibility of heavy metals contamination of ground-
water as a result of sludge spreading at the site is
remote.
t The Cd concentrations in the soil profile (treated and
control plots) were unusually high (approximately 4
vig/g)- The source of Cd was not the result of sludge
spreading, but rather was of natural origin.
Wilmington, Ohio
Sludge Characteristics
Nitrogen and phosphorus The concentrations total M (3.81
percent), organic-N (2.8 percent), NH4-N (1.01 percent), and
N03-N (13.7 ug/g) were within the ranges previously reported
for siudges .
The liquid sludge was spread on the surface at the site and
allowed to dry, resulting in a substantial loss, by volatiliza-
tion, of NH4-N. Based on previous assumptions, this sludge was
capable of supplying 10.65 kg of available N/m ton. At current
fertilizer prices, the equivalent value of this N fertilizer
sludge is $4.68/m ton.
The P concentration of the Wilmington sludge (3.55 percent)
fell into the range commonly reported, but was substantially
greater than the median concentration (2.3 percent). If all the
phosphorus was considered plant available or equal to commercial
sources, the sludge would be an excellent source of
phosphorus; each m ton of sludge would supply the
fertilizer
fertilizer
equivalent of 35.5 kg P which, at current fertilizer prices, has
a value of $35.50/m ton. In terms of N and P fertilizer equiva-
lent, the value of the Wilmington sludge was $40.18 per m ton.
63
-------
The annual estimated application rate was approximately
6.8 m tons/ha, equivalent to 73 kg/ha of available N and 241
kg/ha of total P, in excess of plant requirements. However,
the nitrogen equivalent was possibly less than stated, depending
on NH3 losses from the spreading operation.
Other elements Concentrations of all metals, except Mo and
Zn, were in the normal range and near median concentrations
observed for other sludges. However, Mo and Zn concentrations
were higher, Zn in particular (45,800 yg/g) compared to the
highest value reported by Sommers (27,800 yg/g).
Molybdenum is an essential element for animals at low
concentrations, but is toxic at higher concentrations; concen-
trations of Mo as low as 10 yg/g in forage (Cast, 1976) can
cause a disorder in animals called molybdenosis. The soil pH
of the treated plot was neutral, which makes Mo more plant
available; the alfalfa could absorb quantities of Mo sufficient
to be toxic to animals.
Soil Analyses--
Total metals--Tab!e 18 presents total and DTPA-extractable
metals of treated and control surface and subsurface so.il
samples.
The range in Cd concentration throughout the soil profile
of both the treated and control plots (0.77 and 1.0 yg Cd/g)
was greater than that commonly reported for agricultural soils
(0.5 ug/g). Cadmium was statistically significantly higher in
the control plot subsurface soils, suggesting that these high
levels were due to natural sources.
Zinc, Cu, and Pb showed substantial enrichment in the
treated surface soil. This can be attributed to the high con-
centrations of both metals in the sludge.
The concentrations of the five heavy metals in both the
treated and control plot subsurface soils were nearly the same,
indicating that the metals applied with the sludge were essen-
tially retained in the surface 18 cm.
Molybdenum values of the treated surface and subsurface
soil samples ranged from 2.0 to 3.25 yg/g. Similarly, control
samples showe'd a range of 1.97 to 3.10 yg/g, indicating little
or no appreciable difference between the plots.
DTPA-extractable metals--The DTPA-extractable metal results
corresponded to the trends already discussed for total metals.
The only observable difference between the treated and control
plots was the amount of DTPA-extractable Zn, which had not only
accumulated in the surface layer of the sludged soil, but was
64
-------
CT)
Ol
TABLE 18. CONCENTRATIONS OF TOTAL AND DTPA-EXTRACTABLE METALS IN
COMPOSITE SURFACE AND SUBSURFACE SAMPLES
FROM WILMINGTON, OHIO*
Soil
Depth
- cm -
Treated:
0-18
18-30
30-61
61-91
91-122
Control :
0-18
18-30
30-61
61-91
91-122
-Total t
Cd
0.86
0.89
0.77
1.00
1.10
0.87
0.91
1.08
1.08
1.06
Cu
-
16.0
19.0
22.2
22.8
23.0
14.6
17.6
21.5
23.4
24.8
Ni
- ug/g
24.7
32.3
39.0
44.3
41.8
24.9
31.4
42.3
46.2
44.5
Zn
"- -
190
62.5
65.1
66.0
67.8
49.5
57.3
75.0
74.2
71.3
Pb
47.8
23.5
22.8
20.0
21.4
24.6
22.1
22.7
21.9
20.1
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
Cd
14(16. 3)#
11(12.4)
09(11.7)
16(16)
12(10.9)
13(14. 9)#
12(13.2)
11(10.2)
08(7.4)
09(8.5)
DTPA-Extractable
Cu
- - yg/g
1.86(11.6)
0.94(5.0)
0.74(3.3)
0,66(2.9)
0.71(3.1)
1.38(9.5)
0.98(5.6)
0.79(3.7)
0.69(3.0)
0.79(3.2)
Ni
- -
0.70(2.8)
0.85(2.6)
0.68(1.7)
0.99(2.2)
0.98(2.3)
0.87(3.5)
0.47(1.5)
0.64(1.5)
0.38(0.8)
0.38(0.9)
Zn
27.
1.
1.
0.
0.
1.
0.
0.
0.
0.
5 (14.5)
77(2.8)
08(1.7)
81(1.2)
83(1.2)
20(2.4)
63(1.1)
60(0.8)
57(0.8)
62(0.9)
*0ven-dry weight basis.
tHN03-HC104 digestion.
^Percent of total concentration.
-------
also greater than the control plot in each of the lower depths
of the treated soil. The DTPA-extractable Zn data suggest the
possible movement of sludge-borne Zn to depths as low as 61 cm.
Plant Analyses--
Total metals in alfalfa from the treated and control plots
are presented in Table 19. Concentrations of Cu, Ni, and Zn were
in the range commonly reported for alfalfa, although Cd and Pb
concentrations were slightly higher (Chapman, 1966). Except for
Zn, mean concentrations of metals in treated plot plant materials
were not statistically different from those of the control plot.
Therefore, it would seem that sludge spreading has not resulted
in increased concentrations of Cd, Ni, and Pb in the alfalfa
pi ants.
Moreover, considering the concentration of Zn in the treated
surface soil (190 yg/g), tne enrichment of Zn in alfalfa was
lower than would be expected. In contrast, the concentration of
Zn in treated surface soil at Kendallville, Indiana, was less
(113 yg/g), while the alfalfa had accumulated about twice as
much Zn (83 yg/g) as that grown on the Wilmington treated plot
(40.5 yg/g). Since the pH of the soil at both sites was approxi-
mately the same, these differences do not seem to be explainable
in terms of the soil acidity. Since plant Zn concentrations from
the control plots from the two sites were essentially the same,
the differences in the treated plots apparently were not due to
a plant-aige factor. Other factors, e.g., long-term Zn sludge
concentrations,' fertility level, metal competition, etc., were
probably involved.
The Mo concentration of composite treated plants was 1.99
yg/g compared to a control of 1.34 yg/g. Both of these values
are considerably lower than the 10 yg/g level which researchers
have indicated to be the threshold animal toxicity level (Cast,
1976).
Microbiology--
No intestinal parasite ova were detected in the Wilmington
sludge samples, an atypical result based upon published data
and larger sample bases. The absence of Salmonella sp. or
Shigella sp. was not an unexpected result in view of the small
sample base and the relatively low numbers of these organisms
usually found in sewage solids (Kenner, 1972). The low number
of fecal coliform organisms detected for the August 25, 1976, raw
sludge sample was unexplainable; the stabilized sludge for the
same sampling date was some four logs greater.
The treated and control soils contained like profiles of
fecal coliform and fecal streptococci organisms.
66
-------
TABLE 19. METAL CONCENTRATIONS IN ALFALFA
FROM WILMINGTON, OHIO*
Sample
Treated:
Composite
Section 1
Section 2
3* Section 3
Section 4
Section 5
Mean
Std. Dev.
Control :
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Cd
0.90
1.02
0.83
0.84
0.93
0.79
0.88
0.09
1.00
0.75
1.10
0.56
0.84
1.01
0.85
0.21
Cu
-
8.91
9.10
8.51
7.62
8.41
7.77
8.28
0.60
9.40
9.90
9.95
9.70
8.11
8.46
9.22
0.87
Leaves
Ni
- ug/g -
6.43
7.62
7.24
5.90
8.35
7.76
7.37
0.92
7.18
7.73
7.87
9.04
7.96
8.75
8.27
0.59
Grains
Zn Pb t Cd Cu Ni Zn Pb
- - yg/g - -
37.8 6.30
43.3
42.4
37.6
38.1
41.3
40.5
2.56
37.0 7.79
33.5
34.1
34.3
27.3
32.8
32.4
2.91
*0ven-dry weight basis.
tLead was analyzed on composite
only.
-------
The alfalfa plant specimens selected from the mixed
perennial grasses were associated with fairly high counts of
fecally associated organisms, in comparison to other sites with
other crops. The data are very similar to the Kendallville,
Indiana site, where sludge was applied directly to the low-lying
alfalfa.
Sludge, Soil, and Plant Conclusions--
The Wilmington sludge was an excellent source of nitrogen
and phosphorus. It had a potential fertilizer value of
$40.19/m ton, the highest among the nine sites studied.
The limiting factor in agricultural utilization of this
sludge was probably the exceedingly high Zn content.
The treated plot soil had been substantially enriched
with Zn, but this had not yet resulted in significant
increases in the alfalfa Zn levels.
DTPA Zn indicated possible Zn movement to a depth of at
least 61 cm.
The results obtained indicated that, except possibly
for Zn, the metals applied in the form of sludge had
been almost completely retained by the soil within the
depth of incorporation. Therefore, groundwater contami-
nation from Cd, Cu, Ni, and Pb would not be expected to
have occurred.
Soil and plant molybdenum concentrations were low,
indicating little or no accumulation as a result of
sludge spreading.
Springfield, Missouri
Sludge Characteristics--
Nitrogen and phosphorus Concentrations of N03-N (51.4 ug/g)
and organic-N (4.3 percent) were in the range reported by Sommers
(Table 12). However, the total N (8.48 percent) and NH4-N (4.18
percent) concentrations in the Springfield sludge were substan-
tially higher than the median concentrations of 4.8 and 0.09
percent, respectively, suggesting that this sludge can be an
excellent nutrient when applied to agricultural land.
Spreading of liquid sludges onto the surface without incor-
poration into the soil, as currently practiced at Springfield,
results in substantial loss of NH3 to the atmosphere. Based on
previously stated assumptions, the sludge would supply 29.5 kg
of available N/m ton and would have a current equivalent value
of $12.98/m ton.
68
-------
The P content of the sludge (1.74 percent) was within the
range reported by Sommers, but less than the median P concentra-
tion (2.3 percent). One m ton of the Springfield sludge would
supply 17.4 kg of available P and have a current equivalent
nutrient value of $17.40. The value of the sludge based on the
N and P content is high - $30.38/m ton.
The K content of the sludge (0.54 percent) was considerably
higher than the surveyed median concentration (0.3 percent).
Based upon an annual application of 15.8 m tons/ha, this sludge
would have supplied 466, 275, and 85 kg of available N, P, and
K, respectively, per ha, for the fescue plants.
Other elements--In the Springfield sludge, concentrations
of all metals except Mo were within the reported concentration
ranges (Table 20). However, Ca, Cr, Cd, Ni, and Zn concentra-
tions were considerably higher than the median reported concen-
trations. The sludge was alkaline (pH 8.3), which suggests
that the solubility of the heavy metals was probably low and that
the meta'is were less available for downward movement and plant
uptake.
Total meta1s--Table 20 presents total and DTPA-extractable
metal analyses of the surface and subsurface treated and control
soils. Statistically significant Cd, Zn, Ni, and Pb surface
soil enrichment as a result of repeated sludge applications was
indicated. Concentrations of total metals throughout the soil
profile were generally in the range reported for agricultural
soils, indicating virtually no movement of metals beyond the
surface 20 cm.
The Mo concentrations of the treated surface and subsurface
soil samples ranged from 1.9 to 2.93 ug/g. Similarly, control
samples showed a range of 2.0 to 3.26 yg/g, indicating no
appreciable difference between the plots.
DTPA-extractable metals--There appeared to be no correlation
between concentrations of DTPA-extractable and total metals. The
data indicated accumulations of Cd, Zn, and probably Ni in the
surface so.il as a result of the sludge application.
The amounts of metals extracted by DTPA were higher on the
surface compared to the subsurface soil and were particularly
noticeable in the treated plot. The data suggest that sludge-
borne heavy metals are, in large part, present as metal-orqanic
complexes and more soluble in DTPA than are the metals
indigenous to the soil.
69
-------
TABLE 20. CONCENTRATIONS OF TOTAL AND DTPA-EXTRACTABLE METALS IN
COMPOSITE SURFACE AND SUBSURFACE SAMPLES
FROM SPRINGFIELD, MISSOURI*
Soil
Depth
- cm -
Treated:
0-20
20-41
41-61
61-81
81-122
Control :
0-20
20-41
41-61
61-81
81-122
Total t
Cd
1.17
0.77
0.82
0.83
0.77
0.73
0.68
0.70
0.82
0.89
Cu
-
10.5
13.1
15.7
20.0
16.1
23.6
14.3
12.0
13.2
15.0
Ni
- ug/g
28.9
28.2
47.6
38.7
35.8
19.9
22.7
24.4
28.8
34.4
Zn
- -
108
41.8
48.8
52.9
57.6
36.8
34.8
39.2
45.7
48.0
Pb
40.2
21.4
25.8
28.0
25.1
34.0
24.1
22.1
20.6
26.1
Cd
0.38(32. 5)#
0.11(14.3)
0.07(9.0)
0.07(8.4)
0.06(7.8)
0.11(15.1)
0.09(13.2)
0.07(10)
0.06(7.3)
0.06(6.7)
DTPA-Extractable
7.
1.
1.
1.
1.
7.
2.
1.
0.
1.
Cu
- - yg/9
07(67.3)
80(13.8)
47(9.4)
87(9.4)
12(7.0)
35(31.1)
87(20.1)
32(11)
98(7.5)
36(9.1)
NI
- -
3.18(11)
1.62(5.7)
1.56(3.3)
1.57(4.1)
1.10(3.1)
1.49(7.5)
1.11(4.4)
0.95(3.9)
0.96(3.3)
0.97(2.8)
36
3
2
2
1
1
2
1
Zn
.6 (34)
.03(7.3)
.00(4.1)
.30(4.4)
.00(1.7)
.79(4.9)
.78(8.0)
.42(3.6)
0.68(1.5)
1
.13(2.4)
*0ven-dry weight basis.
fHN03-HCT04 digestion.
* Percent of total concentration.
-------
Plant Analysis--
Table 21 presents total metal analysis of fescue grass
from the treated and control plots and shows concentrations of
Ni and Zn significantly higher in the forage from the treated
plot. The opposite was observed for Cu and Pb. The Cd concen-
tration in section 2 of the control was inexplicable and
affected the mean concentration of Cd in the control forage.
Generally, concentrations of Cd, Cu, Ni, Zn, and Pb in the
forage were in the normal range for fescue (Chapman, 1966).
Plant analysis indicated no apparent problems stemming from
utilization of the forage as animal feed (CAST, 1976).
The Mo concentrations of composite treatment plants were
0.84 yg/g compared to a control of 0.67 ug/g. Both of these
values were considerably lower than the 10 yg/g level which
researchers have indicated to be the threshold animal toxicity
level (Cast, 1976).
Microbiology--
The raw sludge contained ova of one animal parasite, the
stabilized sludge,the ova of one human intestinal and one canine
parasite. The anaerobic digestion process environment was not
sufficiently adverse to inactivate these organisms.
Salmonella sp. was detected in one sample of raw sludge in
very low numbers, while FC and FS organisms were found in numbers
corresponding generally to those reported in the literature.
The treated soils indicated an almost complete absence of
sludge-associated organisms; this was somewhat surprising
because the grass cover crop was used as fodder for beef cattle.
Moreover, the control plot exhibited a higher FS count than the
treated plot, although the absolute numbers were very low. The
soil may have supported only a limited microflora; the total aerobic
bacteria count was some 3 logs below other values for the other
study sites. The reason for this was not readily apparent.
Since the fescue hay from the treated plot showed a high
FS count, it seems probable that the grazing livestock may have
had some effect. It may be assumed with some confidence that
with the absence of fecal organisms in the treated soil, the FS
on the plant tissue was of animal origin, the leaf surface of a
plant having higher rates of microbial inactivation (i.e.,
dessication, ultraviolet radiation) than soil.
Sludge, Soil and Plants Conclusions--
The sludge from the Springfield STP did not contain
excessive concentrations of heavy metals and appears
71
-------
TABLE 21. METAL CONCENTRATIONS IN FESCUE
FROM SPRINGFIELD, MISSOURI*
Sample
Treated:
Composite
Section 1
Section 2
j Section 3
j
Section 4
Section 5
Mean
Std. Dev.
Control :
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Cd
0.25
0.36
0.41
0.32
0.33
0.29
0.34
0.05
0.29
0.27
1.03
0.36
0.24
0.25
0.43
0.34
Cu
-
4.79
4.22
4.68
4.76
4.50
4.97
4.63
0.28
5.79
5.12
5.12
5.22
5.20
5.61
5.25
0.20
Leaves
Ni
- vg/g -
4.27
4.15
4.71
4.21
3.76
5.05
4.38
0.51
3.96
3.76
3.59
3.59
3.25
3.37
3.51
0.20
Grains
Zn Pbt Cd Cu Ni Zn Pb
- - vg/g - -
26.0 2.71
28.4
32.8
32.8
28.7
33.7
31.3
2.52
23.4 5.60
23.8
24.1
26.0
24.5
24.9
24.6
0.86
*0ven-dry weight basis.
tLead was analyzed on composite
only.
-------
to be an excellent source of plant nutrients for the
fescue grown at the sludge-treated site.
There was some indication of Cd, Ni, In, and Pb enrich-
ment of the surface soil as a result of the sludge
spreading. However, these soil concentrations were
still within the range normally reported.
t The metals Cd, Cu, Zn, Ni, and Pb applied in the sludge
over the past 18 years have remained essentially in the
surface 20 cm of soil.
Based on the metal contents of the fescue, the forage
is safe for feeding.
Soil and plant Mo concentrations were low, indicating
no accumulation as a result of sludge spreading.
Chippewa Falls, Wisconsin
Sludge Characteristics--
Nitrogen andphosphorus--As shown in Table 121 concentra-
tions of total N (4.58 percent) , organic N (2.46 percent), NH4-M
(2.12 percent) and N03-N (13.0 Jjg/g were within the ranges pre-
viously reported.
The technique of spreading liquid sludge from the Chippewa
Falls STP onto land and allowing it to dry, prior to incorpora-
tion probably resulted in substantial loss of NH4-N. One m ton
of the sludge would supply the equivalent of 15.5 kg of available
N and have a value of $6.82.
The P concentration of the Chippewa Falls sludge (1.34
percent) fell within the range reported for comparative sludge,
but was considerably less than the reported median concentration
(2 3 percent). One m ton of the Chippewa Falls sludge would
supply 13.4 kg of P and have a value of $13.40. Thus, in terms
of N and P, 1 m ton of this sludge would be worth $20.22.
The annual estimated application rate of the Chippewa Falls
sludge was approximately 16 m tons/ha, equivalent to 248 kg/ha
of available N and 214 kg/ha of total P, in excess of plant
requirements. The nitrogen equivalent was possibly less than
stated, depending on NH3 losses from the spreading operation.
Other elementsConcentrations of all of the elements were
within normal ranges. Only Hg, at 24.1 yg/g, and Se, at 7.6
ug/g were significantly higher than the median values reported-
by Sommers. Since Hg in soil is generally present in an
73
-------
insoluble form, thus unavailable for plant uptake, there is
probably little reason for concern.
Soil Analyses--
Total metals--As is apparent from Table 22, which presents
total and DTPA-extractabl e metals for treated and control
surface and subsurface plots, the concentrations of total
metals Cd, Cu, Ni, Zn, and Pb in soils from both the treated
and control plots were in the normal range, although Cu and Zn
concentrations in the surface 20 cm of the treated soil were
greater than the control.
The soil at this site was sandy and strongly acidic, so
some metal migration would be expected. However, because of the
low metal content in the sludge and relatively low amount spread
(80 m tons/ha) at this site to date, no migration of metals
beyond the,depth of incorporation had occurred.
DTPA-extractable metals--Data on DTPA-extractable metals
showed Cu, Ni, and Zn enrichment of the surface soil as a result
of the sludge application. The percent of total metals extracted
by DTPA from the surface soil of the treated plot was higher
than from the control, indicating that sludge-borne metals are
more soluble in DTPA than are native metals. The results
indicate little or no migration of Cd, Cu, Ni, and Zn to lower
soil depths.
Plant Analyses--
Concentrations of Cd, Cu, Ni, Zn, and Pb in the leaves and
qrains of soybeans qrown on the treated and control plots are
presented in Table 23.
Except for Ni concentration in leaves, mean concentrations
of the metals analyzed for both leaves and grains were signifi-
cantly higher in plants grown in the treated plot than those in
the control. The increases of metal concentrations in the grains
and leaf tissue appeared to be parallel, although the soybean
grains contained less Cd, Ni, and Pb than the leaves. In the
treated plot, Cu concentration appeared to be higher in the grain
than in the leaves, while Zn concentrations showed no difference.
Although sludge application at Chippewa Falls resulted in
significant increases in metal concentrations in soybean grains
and leaves, the concentrations were within the range normally
reported for soybeans. The concentration of Cd, the element of
most concern in health problems, was very low in the soybean
seeds; the soybeans harvested at this site may be considered
safe for consumption by animals or man.
74
-------
tn
TABLE 22. CONCENTRATIONS OF TOTAL AND DTPA-EXTRACTABLE METALS IN
COMPOSITE SURFACE AND SUBSURFACE SAMPLES
FROM CHIPPEWA FALLS, WISCONSIN*
Soil
Depth
- cm -
Treated:
0-20
20-46
46-61
61-91
91-122
Control :
0-20
20-46
46-61
61-91
91-122
Cd
0.42
0.38
0.35
0.31
0.44
0.46
0.34
0.48
0.31
0.33
Cu
-
17.4
10.5
11.3
13.0
18.5
7.6
7.6
12.2
15.7
13.8
-Total
Ni
- yg/g
14.2
16.7
16.1
14.6
14.4
15.2
14.3
18.3
19.6
16.3
t
Zn
- -
49.3
29.4
21.8
22.1
24.7
31.3
24.2
30.2
27.8
19.5
DTPA-Extractable
Pb
9.90
4.40
4.00
2.40
2.70
8.50
5.70
5.60
4.00
2.10
Cd
0.06(14.3)*
0.03(7.9)
0.02(5.7)
0.02(6.5)
0.03(6.8)
0.06(13)f
0.03(8.8)
0.02(4.2)
0.03(9.7)
0.02(6.1)
Cu
- - yg/g
3.44(19.8)
0.55(5.2)
0.57(5.0)
0.34(2.6)
0.31(1.7)
0.42(5.5)
0.23(3.0)
0.17(1.4)
0.36(2.3)
0.23(1.7)
Ni
- -
1.00(7.
0.36(2.
0.39(2.
0.41(2.
0.68(4.
0.33(2.
0.33(2.
0.41(2.
0.33(1.
0.21(1.
Zn
0)
2)
4)
8)
7)
2)
3)
2)
7)
3)
4.
0.
1.
0.
1.
1.
0.
0.
1.
0.
28(8.7)
61(2.1)
00(4.6)
89(4.0)
17(4.7)
54(4.9)
39(1.6)
79(2.6)
12(4.0)
89(4.6)
*0ven-dry weight basis.
WN03-HC104 digestion.
^Percent of total concentration.
-------
TABLE 23. METAL CONCENTRATIONS IN SOYBEANS
FROM CHIPPEWA FALLS, WISCONSIN*
Sample
Treated:
Composite
Section 1
Section 2
1 Section 3
Section 4
Section 5
Mean
Std. Dev.
Control :
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Cd
0.97
2.31
0.95
0.92
1.48
1.24
1.38
0.57
0.82
1.21
0.66
0.72
0.80
0.77
0.83
0.22
Cu
-
11.9
14.9
15.1
12.5
11.5
12.6
13.3
1.59
10.4
11.1
10.0
11.0
9.6
10.6
10.5
0.65
Leaves
Ni
- yg/g -
10.8
14.5
10.4
10.7
17.8
13.3
13.3
3.04
10.4
15.5
8.7
9.1
9.6
9.9
10.6
2.80
Zn
-
87.5
149
113
80.5
111
89.9
109
26.4
60.4
65.2
51.6
56.4
52.5
60.8
57.3
5.72
Pb t Cd
5.50 0.12
0.12
0.09
0.15
0.19
0.11
0.13
0.04
8.20 0.07
0.03
0.06
0.06
0.12
0.09
0.07
0.03
Cu
-
18.5
18.3
19.9
19.8
18.9
19.0
19.2
0.67
11.4
11.7
10.8
11.5
10.7
11.0
11.1
0.44
Grains
Ni
- vg/g -
4.01
3.09
5.18
4.41
3.57
4.06
4.06
0.80
1.18
1.20
2.25
1.03
1.88
2.74
1.82
0.71
Zn Pbt
-
93.1 0.74
86.2
106
99.8
92.6
99.5
96.8
7.60
74.3 0.60
71.3
72.6
69.2
67.6
67.1
69.6
2.36
*0ven-dry weight basis.
tLead was analyzed on composite only.
-------
Microbiology--
No intestinal parasite ova, salmonella, or shigella
organisms were detected in the sludge samples. FC and FS
organisms were found in numbers generally corresponding to
those reported in the literature.
The soils had not been treated with sludge for some three
months prior to the sampling date, August 3, 1976. Both treated
and control plots exhibited similar microbiological character
indicating homeostasis and the achievement of some equilibrium
condition.
The soybean tissue contained about the same concentration
of FC and FS organisms as did vegetation of similar size and
associated cultural practices. The organisms can most likely be
traced to aeolian transport in association with dust particles,
the result of tillage or other man-induced or natural activity
in the field.
Sludge, Soils, and Plants Conclusions--
t Copper, Ni, and Zn enrichment of the surface-treated
soil was observed to be the direct result of repeated
sludge applications.
0 The data suggest no migration of any metals through the
soil profile.
e Cd was statistically significantly (treated vs. control)
higher in the petioles; the difference was 0.55 yg/g.
ft The possibility of groundwater contamination is remote,
in view of the restricted heavy metal movement and the
low total sludge loadings.
Hopkinsvi11e, Kentucky
Sludge Characteristics--
Nitrogen andphosphorus--The concentrations of NO^-N (10.2
yg/g), organic-N (1.83 percent) , total N (2.37 percent), and
NH4-N (0.54 percent) in the Hopkinsville sludge were in the range
reported for sludges.
The practice of spreading liquid sludges on the surface at
Hopkinsville and allowing them to dry prior to incorporating
into the soil, probably resulted in significant loss of NHa,
greatly reducing the nutrient value of the sludge. Based upon
77
-------
previous assumptions, each m ton of sludge would supply 6.30 kg
of available N and have a value of $2.80.
The concentration of phosphorus in the sludge (1.56 percent)
was in the range, but slightly below the median concentration
reported (2.3 percent). If all of the P in the sludge were
considered plant available, 1 m ton of the Hopkinsville sludge
would supply the equivalent of 15.6 kg P, and have a value of
$15.60. If only N and P were considered, the value of the sludge
would be $18.40/m ton.
The annual estimated application rate was approximately 22
m tons/ha, equivalent to 140 kg/ha of available N and 343 kg/ha
of total P, the approximate requirements of fescue. The N
equivalent was possibly less than stated, because of NH3 losses
from the spreading operation.
Other elements Concentrations of all of the elements were
within the normal ranges reported, although the trace element
Hg was somewhat higher and Cd, Cr, Cu, Mn, Pb, and Zn less than
median concentrations reported. In view of heavy metal content,
the Hopkinsville sludge is suitable for application onto agri-
cultural land.
Soil Analyses
Total metals Table 24 presents total and DTPA-extractable
metal analyses of treated and control surface and subsurface
soils. Total concentrations of the metals Cd, Cu, Ni, Zn, and
Pb analyzed in the HN03-HC104 digests were within the ranges
normally reported for soils; Cd, Cu, Zn, and Pb enrichment was
noted in the surface soil as a result of sludge applications.
The data indicated virtually no evidence of metal movement
below the depth of incorporation; the application rate was not
heavy, and the sludge did not contain large quantities of any
heavy metal.
DTPA-extractabl e metal s Cadmium, Cu, and Zn enrichment in
the surface soilhas apparently resulted from sludge application
practices over the years (Table 24). Limited Cu and Zn migration
to 30 cm was noted.
The DTPA-extractability, as expressed by percent of total
metals extracted, was greater in the surface than the subsurface
layers. The sludge-borne metals were more effectively extracted
by DTPA than the metals occurring naturally in the soil.
Plant Analyses--
Metal analyses on fescue grass of the treated and control
plots are presented in Table 25. Although concentrations of Cu,
Cd, Zn, and Pb were hioher in the treated plot than the control,
78
-------
IO
TABLE 24. CONCENTRATIONS OF TOTAL AND DTPA-EXTRACTABLE METALS IN
COMPOSITE SURFACE AND SUBSURFACE SAMPLES
FROM HOPKINSVILLE, KENTUCKY*
Soil
Depth
- cm -
Treated:
0-15
15-30
30-61
61-91
91-122
Control :
0-15
15-30
30-61
61-91
91-122
Total t
Cd
1.33
0.95
0.69
0.84
0.63
0.83
0.77
0.78
1.02
0.68
Cu
26.3
17.7
18.2
15.4
15.4
9.8
13.7
16.8
15.4
15.4
Ni
- vg/g
24.8
27.0
39.2
26.3
35.4
21.5
25.6
37.2
26.8
36.4
Zn
- -
109
68.0
55.0
60.4
60.1
50.2
62.3
64.0
71.6
78.0
Pb
30.2
17.7
23.2
16.0
24.2
19.5
18.0
39.4
15.3
23.6
Cd
0. 30(22. 6J*
0.08(8.4)
0.07(10.1)
0.05(6.0)
0.06(9.5)
0.09(10.8)*
0.05(6.5)
0.08(10.3)
0.05(4.9)
0.05(7.4)
DTPA-Extractable
Cu
. .4
6.12(23
1.20(6.
0.55(3.
0.54(3.
0.47(3.
0.79(8.
0.48(3.
0.40(2.
0.50(3.
0.60(3.
yg/9
.3)
8)
0)
5)
1)
1)
5)
4)
3)
9)
Ni
- -
1.59(6.4)
1.10(4.1)
1.03(2.6)
0.80(3.0)
0.70(2.0)
1.20(5.6)
1.10(4.3)
1.40(3.8)
1.30(4.9)
1.30(3.6)
Zn
17.
1.
0.
0.
0.
0.
0.
0.
0.
0.
0X15.6)
49(2.2)
48(0.9)
46(0.8)
44(0.7)
94(1.9)
42(0.7)
39(0.6)
40(0.6)
49(0.6)
* Oven-dry weight basis,
tHN03-HCT04 digestion.
* Percent of total concentration.
-------
00
o
TABLE 25. METAL CONCENTRATIONS IN FESCUE
FROM HOPKINSVILLE, KENTUCKY*
Sample
Treated:
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Control :
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Cd
0.39
0.30
0.18
0.39
0.28
0.22
0.27
0.08
0.23
0.25
0.19
0.08
0.14
0.23
0.18
0.07
Cu
-
5.39
4.63
4.83
11.7
7.50
7.80
7.29
2.87
4.64
4.34
4.83
3.64
4.14
4.98
4.39
0.54
Leaves
Ni
- ug/g -
3.10
3.65
3.89
6.38
3.65
3.83
4.28
1.18
2.70
2.92
3.81
2.92
3.79
5.10
3.71
0.89
Grains
Zn Pbf Cd Cu Ni Zn Pb
- - yg/g - -
31.3 5.08
27.6
26.7
55.3
40.7
37.6
37.6
11.6
20.1 4.20
21.4
21.7
17.9
18.4
23.2
20.5
2.28
*0ven-dry weight basis.
tLead was analyzed on composite
only.
-------
these concentrations were within the range normally reported for
fescue (Chapman, 1966). Moreover, mean concentrations in the
forage were in most analyses in close agreement with the com-
posite sample representing the five sections.
Microbiology--
The raw sludge sampled on May 20, 1976,contained two species
of ova; one of human intestinal parasites and one of animal
origin. The second sample sequence, obtained on August 25, 1976,
contained the ova of a canine parasite. The presence of these
ova was not unexpected.
The raw sludge for this site contained Salmonella sp. (sera-
typed as, Salmonella paratyphi C.). Concentrations of other
index bacteria were of the right order of magnitude in comparison
to published data on the microbiological character of typical
sewage sludges.
As sludge was applied to the test plot only two weeks
before sampling, the stabilized sludge microbiological data can
be considered to be fairly representative. The chronology of
short-term inactivation of microorganisms demonstrated in the
soil-sludge matrix was of special interest.
Microbial populations of index organisms in the treated
soil profile were two to three logs higher than comparable
sites, where sludge had been applied at a much earlier date,
(prior to the actual field sampling). The concentration of
organisms in a vertical dimension from surface to 122 cm was
also relatively constant. The ratio of FS/FC organisms (3:1 to
30:1) suggested the influence of livestock (Mara, 1977), in the
treated plot, as reported for this site under Farming Practices.
No intestinal parasite ova were recovered from the soils.
The fescue hay (61 cm during sampling) was high enough to have
escaped direct contamination from the sludge applied two weeks
previously. The low numbers of index organisms detected in the
plant tissue support this; the findings compare well to the
other sites for which "tall" crops exhibited a low level of
sludge-associated organisms.
Aeolian transport in association with dust particles is a
likely source of the low-level fecal contamination.
Sludges, Soils, and Plant Conclusions--
Accumulation of Cd, Cu, Zn, and Pb in the surface soil
of the sludge-treated plots was evidenced, but the con-
centrations of these metals were within the ranges
normally found in soils.
81
-------
DTPA analyses suggest limited movement of Cu and Zn to
a depth of 30 cm.
Since no depth of groundwater table was given for the
Hopkinsville site, it was difficult to estimate the
possibility of groundwater pollution. However, since
the metals analyzed showed practically no movement
beyond the depth of incorporation,and the soil proper-
ties at this site restricted downward migration of heavy
metals, it is reasonably safe to assume that the land-
spreading practices have not resulted in contamination
of the groundwater with heavy metals.
The fescue Cd concentrations from the treated plot were
statistically significantly higher than those from the
control (difference of 0.09 yg/g), but were within the
range normally reported for fescue.
Frankfort, Indiana
Sludge Characteristics--
Nitrogen and phosphorus The concentrations of total N
(3.04 percent), N03-N (13.4 yg/g), NH4-N (0.74 percent), and
organic-M (2.3 percent) in sludge from the Frankfort STP were
within the reported ranges.
The practice of spreading liquid sludges onto the surface
without incorporation into the soil at Frankfort probably
resulted in considerable 'loss of ammonia to the atmosphere.
Based on previous assumptions, the Frankfort sludge contained
8.3 kg available N and had a value of $3.65/m ton.
The P concentration of the sludge (1.57 percent) was in
the range reported for sludges, but less than median concentra-
tions (2.3 percent). One m ton of the Frankfort sludge would
supply 15.7 kg of available P and have a value of $15.70. In
terms of N and P contents, the sludge was worth $19.35/m ton;
the sludge value was based principally on its P content.
The annual estimated application rate was approximately 30
m tons/ha, equivalent to 249 kg/ha of available N and 471 kg/ha
of total P, in excess of plant requirements. The N equivalent
was possibly less than stated depending on NH3 losses from the
spreading operation.
Other elements Concentrations of all metals were comparable
to median concentrations normally reported for sludges except
for Cd (an excessively high 1,500 yg/g). Based on the Cd con-
centration and high Cd/Zn ratio' (0.698) , the Frankfort sludge
is not suitable for agricultural utilization.
82
-------
Soil Analyses--
Total metals--Table 26, which presents total and DTPA-
extractable metal analyses of treated and control surface and
subsurface soils, shows significant accumulations of Cd, Cu,
Ni, Zn, and Pb in the surface soil as a result of sludge
spreading over the years. However, except for Cd, concentrations
of metals in the surface soil from the sludge-treated plots
were within the range normally reported for soils.
There is indication that Cd has moved to at least the 61-cm
depth in the treated plot. Some movement of Zn into the 15- to
40-cm depth is also suggested.
DTPA-extractable metals Concentrations of DTPA-extractable
metals were higher in the surface than the subsurface soils for
both treated and control plots. Accumulations of heavy metals
were more evident from the DTPA extraction data than the total
metal data. Again, this indicates movement of Cd to at least a
depth of 61 cm.
DTPA appeared to extract considerably higher percentages of
the total Cd than Cu, Ni, or Zn. The percentage of total metals
extracted by DTPA was greater in the surface soil than in the
subsurface soil from the treated plot.
Plant Analyses--
There were no major differences in concentrations of Ni,
Zn, or Pb in the leaf tissue of wheat from both treated and
control plots, as shown in Table 27. This was not in agreement
with the soil data. However, since the DTPA-extractable concen-
trations of these three metals were relatively low in the
sludged soil, variations of this type can be expected.
Concentrations of Cu and noticeably Cd in wheat leaves
increased as a result of sludge application. However, these Cu
concentration levels were considered normal and should not
present a health hazard.
Except for Cd, the metal concentrations in wheat grains
from the treated plot were slightly lower than the control plot.
The relatively low concentrations of these metals in the DTPA
extracts could in part account for this observation.
Probably, the most significant finding was the elevated
concentrations of Cd in the wheat grains of the treated plot.
Cadmium values varied from 0.58 to 1.89 yg/g with a mean of
1.26 yg/g. The difference in Cd content between the treated and
control plot was about 1.1 yg/g. Considering that wheat grown
at this sludge-treated site is used for flour, the Cd level in
the grains could pose a health hazard. Assuming a per-capita
83
-------
00
TABLE 26. CONCENTRATIONS OF TOTAL AND DTPA-EXTRACTABLE METALS IN
COMPOSITE SURFACE AND SUBSURFACE SAMPLES
FROM FRANKFORT, INDIANA *
Soil
Depth
- cm -
Treated:
0-15
15-40
40-61
61-91
91-122
Control :
0-15
15-40
40-61
61-91
91-122
lotalt
.Cd
12.9
2.17
1.05
0.92
0.83
0.92
0.75
0.80
0.79
0.84
Cu
-
30.0
15.1
19.1
19.1
22.7
10.6
15.5
20.9
22.0
22.7
Ni
- ug/g
25.5
24.5
34.6
34.3
38.5
19.9
32.6
37.8
42.0
44.5
Zn
"- -
88.0
61.6
57.0
56.1
59.1
49.2
54.0
60.8
57.2
55.3
Pb
27.8
16.9
17.9
19.9
18.4
17.2
21.0
21.0
17.3
18.2
Cd
7.70(59.7)#
0.87(40.1)
0.28(26.7)
0.17(18.5)
0.13(15.7)
0.18(19.6)*
0.08(10.7)
0.07(8.8)
0.07(8.9)
0.07(8.3)
DTPA-Extractable
Cu
- - yg/g
5.75(19.2)
1.60(10.6)
1.15(6.0)
1.21(6.3)
0.91(4.0)
1.24(11.7)
0.92(5.9)
0.90(4.3)
0.70(3.2)
0.60(2.6)
Ni
- -
2.78(10
1.70(6.
1.80(5.
1.70(5.
1.70(4.
1.87(9.
1.50(4.
1.50(4.
1.50(3.
1.20(2.
9)
9)
2)
0)
4)
4)
6)
0)
6)
7)
Zn
8.10(9.
1.74(7.
1.00(1.
0.69(1.
0.61(1.
1.62(3.
0.60(1.
0.54(0.
0.38(0.
0.38(0.
2)
0)
8)
2)
0)
3)
1)
9)
7)
7)
tOven-dry weight basis.
tHN03-HCT:04 digestion.
# Percent of total concentration.
-------
TABLE 27. METAL CONCENTRATIONS IN WHEAT
FROM FRANKFORT, INDIANA*
Sample
Treated:
Composite
Section 1
Section 2
o Section 3
n
Section 4
Section 5
Mean
Std. Dev.
Control :
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Cd
0.87
0.85
0.85
0.56
1.01
1.32
0.92
0.28
0.28
0.27
0.37
0.20
0.20
0.34
0.28
0.08
Cu
-
6.50
6.93
6.32
6.68
6.81
6.99
6.75
0.27
5.81
6.32
5.95
5.95
5.53
5.77
5.90
0.29
Leaves
Ni
- vg/g -
3.61
3.99
2.85
3.80
2.47
3.80
3.38
0.68
3.99
5.38
3.99
3.80
3.99
3.61
4.15
0.70
Zn
-
30.4
32.3
29.8
28.7
29.3
28.7
29.8
1.49
29.1
26.7
33.3
27.1
25.8
26.7
27.9
3.04
Pbt Cd
1.78 1.24
0.58
1.34
1.38
1.13
1.89
1.26
0.47
1.68 0.20
0.22
0.19
0.16
0.20
0.21
0.20
0.02
Cu
-
4.64
4.16
4.68
4.83
4.55
5.01
4.65
0.32
5.95
6.66
6.00
5.99
5.90
6.28
6.17
0.31
Grains
Ni
- yg/g -
1.34
1.08
1.20
1.27
1.18
1.45
1.24
0.14
1.87
1.88
1.85
1.57
2.18
2.41
1.98
0.32
Zn Pb
-
44.8 0.67
40.4
45.7 ,
51.4
44.4
43.5
45.1
4.04
57.0 0.73
61.9
55.9
52.6
59.9
57.3
57.5
3.60
*0ven-dry weight basis.
ttead was analyzed on composite
only.
-------
consumption of TOO g of wheat/day, and that all of the Cd in
this wheat is carried through the milling processes, the daily
intake of Cd from this source could be 126 yg or, roughly,
double the total average daily intake.
The Zn concentration of the control wheat grains was
significantly higher than those from the treated plot. The
immature leaves (stalk and grain) from the treated and control
plots, however, had Zn concentrations approximately the same.
The treated surface soil Zn levels (88 yg/g) were indicative
of enrichment due to sludge utilization when compared to the
control plot (49.2 yg/g). Since the Cd levels in the grains
were as high as shown, possible suppression of Zn uptake is
indicated.
Microbiology--
The raw and stabilized sludge contained ova of three
species, two of the common human parasitic helminths and one of
a canine parasite. Viability tests for these ova were inconclu-
sive because of the low density of the eggs for which incubation
and embryonation could be attempted.
Fecal coliform concentrations in the raw sludge were
unusually low. There is no rational explanation for this
anomaly; fecal streptococci concentrations in the raw sludge
appeared to be of the right order of magnitude in comparison
to other published data. No salmonella or shigella species
were detected.
Populations of index bacteria in the test and control plots
were almost identical, suggesting that both microbial populations
were homeostatic at some desirable equilibrium condition.
The spring wheat tissue suggested some evidence of sludge con-
tamination probably associated with aeolian transport. The numbers of FC
were very low to none, while the FS concentration was of the
same order of magnitude as the corn leaf tissue from Columbus,
Indiana.
Sludge, Soil, and Plants Conclusions--
The high Cd concentration of the Frankfort sludge
indicates that it is not suitable for utilization on
agricultural land.
t Repeated sludge applications have resulted in surface
accumulations of all 5 metals measured.
Total and DTPA-extractable analyses indicate that Cd
has migrated to at least the 61-cm level.
86
-------
The high application rates and elevated Cd in the sludge
have resulted in elevated Cd wheat grain levels posing
a possible public health hazard.
t Section variations in surface soil Cd concentrations
in the treated plot relate well to the respective Cd
wheat grain values from those same sections.
The Zn concentrations in wheat grains from the treated
plot were significantly lower than the control, suggest-
ing a possible suppression as a result of the high Cd
uptake.
Kendallville, Indiana
Sludge Characteristics--
Nitrogen and phosphorusThe concentrations of total M
(1.76 percent), organic-N (1.48 percent), NH*-N (0.28 percent)
and N03~N (4.05 yg/g) in sludge from the Kendallville STP were
in the ranges previously reported.
Spreading liquid sludge onto the surface without incorpora-
tion into the soil probably resulted in considerable loss by
volatilization of ammonia-N. Based on previous assumptions, the
sludge contained 4.34 kg of available N and had a market value
of $1.91/m ton.
The P concentration of the sludge (1.41 percent) was in the
range reported by Sommers but considerably less than the
reported median concentration (2.3 percent). One m ton of the
Kendallville sludge would supply 14.1 kg of available P and
have a current value of $14.10. In terms of N and P contents,
the sludge was worth $16.01/m ton, a value principally based on
its P content.
The annual estimated application rate was approximately
19.7 m tons/ha. This is equivalent to 85 kg/ha of available N
and 278 kg/ha of total P, excessive for alfalfa requirements.
The N equivalent was possibly less than stated depending on NH3
losses from the spreading operation.
Other el ements--Concentrations of all metals, except Se,
Mn, and Co were within the reported ranges. However, concentra-
tions of Mg, Cd, Cr, Pb, Se, and Zn were greater than median
concentrations. Additions of Mg to the soil via sludge applica-
tion would probably not have an adverse effect on either yield
or quality of the crop (alfalfa), while additions of Cd, Cr, Pb,
Se, and Zn might.
87
-------
The sludge from Kendallville contained an unusually high
concentration of Se (17.2 ug/g), which when present in an
alkaline soil (such as the soil in Kendallville) at concentra-
tions much above a few ug/g, can be absorbed by certain forage
crops in amounts considered unsafe for animal consumption.
Based on metal concentrations in the sludge and the total
quantity of sludge applied over the years, Zn would be the
limiting element in determining application rates.
Soil Analyses--
Total metals--Table 28 presents total and DTPA-extractable
metal analyses of the treated and control surface and subsurface
soil samples. The total concentrations of Cd, Cu, Ni, Zn, and
Pb were in the range commonly reported.
In the treated plot, the concentrations of Cu, Ni, Zn, and
Pb in surface soils were greater than in the subsurface soils,
while metal concentrations in subsurface soils were reasonably
uniform throughout the soil column. Essentially all of the
metals applied to the surface of the treated plot were concen-
trated in the surface soil. The elevated concentrations of Cu,
Ni, Zn, and Pb in the treated surface soil were caused by
repeated sludge applications.
Selenium concentrations for surface and subsurface composite
treated and control soils were all reported as being <0.016yg/g.
DTPA-extractable metals--The trends for DTPA-extractable
metals were somewhat comparable to those for the total metals
(Table 28); concentrations in the treated surface soil were
greater than in each of the successive subsurface layers. The
treated plot DTPA Zn and Cu results indicated possible limited
movement to a depth of 30 cm. The control plot showed metal
concentrations similar in relation to depth to those for the
treated plot, although absolute concentration differences between
the control and treated soils were appreciable. DTPA also
appeared to extract a considerably higher percentage of the
total Cd, than Cu, Ni, or Zn.
Concentrations of metals in the surface soil composite
compared very well with the mean of the samples making up the
composite, verifying the relative accuracy of the sample taking,
compositing, and analysis of surface soil samples.
Plant Analysis--
Total metal analysis of alfalfa from the treated and
control plots is presented in Table 29. The concentrations of
Cd in alfalfa plants for both plots (0.6 to 0.9 ugCd/g) were
somewhat greater than those commonly observed for plants grown
on soils from other regions (0.05 to 0.2 pgCd/g). The only
88
-------
co
to
TABLE 28. CONCENTRATIONS OF TOTAL AND DTPA-EXTRACTABLE METALS IN
COMPOSITE SURFACE AND SUBSURFACE SAMPLES
FROM KENDALLVILLE, INDIANA*
Soil
Depth
- cm -
Treated:
0-20
20-30
30-61
61-91
91-122
Control :
0-20
20-30
30-61
61-91
91-122
-Total t
Cd
0.52
0.16
0.25
0.46
0.60
0.29
0.22
0.28
0.55
0.51
Cu
-
21.8
19.6
21.0
21.3
19.7
11.5
14.6
19.9
19.4
18.5
Ni
- wg/g
26.5
37.3
44.9
44.6
43.4
20.6
28.2
38.0
40.6
37.7
Zn
. _
113
64.8
67.0
65.7
63.9
55.0
60.3
66.9
61.9
57.6
Pb
32.9
12.9
13.0
13.0
14.5
11.3
11.0
12.2
12.3
12.8
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
Cd
27(51.9)*
14(87.5)
12(48)
11(23.9)
11(18.3)
17(58. 6)#
16(72.7)
13(46.4)
13(23.6)
11(21.6)
DTPA-Extractable
Cu
- - yg/9
5.92(27.1)
2.46(12.6)
1.10(5.2)
0.95(4.5)
0.95(4.8)
1.50(13)
1.46(10)
1.21(6.1)
0.95(4.9)
0.89(4.8)
Ni
- -
2.29(8.6)
1.40(3.8)
1.28(2.9)
1.27(2.9)
1.27(2.9)
1.82(8.8)
1.55(5.5)
1.16(3.1)
1.21(3.0)
1.22(3.2)
Zn
27.
4.
1.
1.
0.
2.
1.
1.
0.
0.
2 (24.2)
63(7.2)
02(1.5)
06(1.6)
92(1.4)
81(5.1)
66(2.8)
08(1.6)
59(1.0)
89(1.6)
*0ven-dry weight basis.
tHN03-HCT04 digestion.
^Percent of total concentration.
-------
TABLE 29, METAL CONCENTRATIONS IN ALFALFA
FROM KENDALLVILLE, INDIANA*
Sample
Treated:
Composite
Section 1
Section 2
> Section 3
Section 4
Section 5
Mean
Std. Dev.
Control :
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Cd
0.89
0.74
0.89
0.65
0.68
0.74
0.74
0.09
0.74
0.62
0.63
0.57
0.61
0.57
0.60
0.03
Cu
-
8.48
9.77
10.70
8.98
8.23
8.88
9.31
0.95
8.83
7.77
8.46
9.72
8.28
8.08
8.46
0.75
Leaves
Ni
- ug/g -
6.44
6.63
7.76
7.28
6.78
6.63
7.02
0.49
5.37
6.95
6.84
6.78
6.63
6.29
6.70
0.26
Grains
In Pbt Cd Cu Ni Zn Pb
- - yg/g - -
78.1 5.42
61.9
145
57.8
73.9
76.6
83.0
35.5
37.6 5.86
31.5
37.2
40.0
37.8
35.9
36.5
3.15
*Qven-dry weight basis.
tLead was analyzed on composite
only.
-------
other metal constituent which exceeded normal concentration
levels in alfalfa was Zn.
The mean concentration between treated and control Cu and
Ni values in the alfalfa was not significantly different. Mean
plant Cd concentrations from the treated plot (0.74 yg/g) were
slightly higher than the mean for the control plot (0.60 yg/g).
The most notable difference occurred with Zn; mean Zn concentra-
tions for alfalfa grown on the treated plot (83 yg/g) were
substantially higher than for the control (36.5 yg/g). Phyto-
toxic concentrations of Zn for alfalfa are not well established,
but are suspected to occur at about 150 yg/g; this level had
not been approached except in section 2 of the treated plot.
Treated and control composite plant samples showed Se
levels of <0.016 yg/g.
Microbiology--
No intestinal parasite ova were detected in any of the
sludge samples from Kendal1vi11e. The small difference in
numbers of FC and FS in both raw and stabilized sludge at this
facility can be attributed in part to inadequate digester
capacity and, during certain periods of high solids loading,
the partial stabilization of the sludge before its application
to the land. The high concentration of indicator organisms in
the applied sludge did not appear to alter the percent inactiva-
tion occurring in the soil-sludge environment. As measured by
the concentration of FC and FS organisms in the soil, die-off
in excess of 99 percent was indicated.
In the crop rotation scheme for the treated plot, the
alfalfa is cut one year and grazed the next; the sampling year
was the year for cutting. Had livestock been grazing the
treated field in the'sampling year, higher densities of FS would
likely have been detected in the soil.
Leaf tissue contained relatively high concentrations of
both FC and FS organisms. This is readily explained: the
perennial alfalfa was in the soil and established during the
periods when the liquid sludge was applied. It is probable
that not even the frequent summer rainfall at this site would
wash the vegetative structure free of sludge-associated microbes;
the low-lying nature of the alfalfa plant and its dense leaf
structure would also favor entrapment of sludge-index bacteria.
No helminth ova were found on the leaf tissue, although from
the sparse evidence because of the operational peculiarities
of this sludge application system and cover crop, it should not
be inferred that they are not in fact present.
91
-------
Sludge, Soil, and Plant Conclusions--
Copper, Ni, Zn, and Pb concentrations were statistically
significantly greater on the treated surface soil. This
was the direct result of repeated sludge applications.
The high concentrations of Zn in the soils of the
treated plot have resulted in similarly elevated Zn
concentrations in the alfalfa plants.
The Pb enrichment of the treated soils has not resulted
in elevated Pb alfalfa levels.
Total metal analyses indicate no significant movement
of metals in the surface profile, while DTPA Cu and Zn
results indicate possible limited movement to 30 cm.
t The impact on groundwater is probably minimal.
Cd concentrations in the alfalfa grown on the treated
plot were statistically significantly greater than Cd
levels of the control crop; the difference was 0.14
ug/g.
Selenium had not accumulated in the surface and sub-
surface soil.
Columbus, Indiana
Sludge Characteristics--
Nitrogen and phosphorus The concentrations of total N
(3.57 percent), N03-N (60 ug/g), NH4-N (1.27 percent), and organic
N (2.3 percent) in the Columbus sludge were in the ranges pre-
viously reported.
The spreading of liquid sludges onto the surface without
soil incorporation has probably resulted in considerable volatil-
ization of NH4-N to the atmosphere. Based on previous assump-
tions, the Columbus sludge contains 10.95 kg available N and has
a value of $4.82/m ton at current fertilizer prices.
The P concentration of the sludge (1.33 percent) was in
the range normally reported for sludges, but less than the
reported median value (2.3 percent). If all, of the P in the
sludge is considered available, 1 m ton of the Columbus sludge
would supply 13.3 kg of available P and have a market value of
$13.30. Combining the N and P contents, the sludge has a value
of $18,12/m ton.
92
-------
The annual estimated application rate is approximately
32.5* m tons/ha, equivalent to 356 kg/ha of available N and
865 kg/ha of total P, which is in excess of plant requirements.
The nitrogen equivalent is possibly less than stated depending
on NH3 losses from the spreading operation.
Other elements Concentrations of heavy metals and other
constituents, except Co analyzed in the Columbus sludge fell
within typical reported ranges, although the concentrations of
Ni and Se were slightly higher than reported median concentra-
tions.
Soil Analyses--
Total metals--Tab!e 30 presents total and DTPA-extractable
metal analyses of the treated and control surface and subsurface
soils. The total concentrations of Cd, Cu, Ni, Zn, and Pb in
the surface soil were very high and reflected the substantial
sludge applications made to this site over the past several
years.
There were indications that Ni and probably Pb had moved to
a depth of at least 46 cm in the treated plot. Cadmium at the
two lowest depths of the treated plot was high (0.78 and 1.30
yg/g> respectively) but lower than the control, indicating high
Cd levels of natural origin. Further interpretation of
analytical data relative to metal movement through the soil
column was difficult due to the extensive earth moving required
prior to replanting the plot to corn (spring 1975).
DTP A-ex tractable me ta Is Concentrations of DTPA-extractabl e
metals showed trends similar to those observed for total metals
Concentration of DTPA-extractable Ni in the surface soil of the
treated plot was considerably greater than that normally
reported for sludge amended soils. Movement of Ni to the 30-
to 46-cm depth or lower was suggested by the DTPA data.
The DTPA extractability of heavy metals in the treated plot
was not as high as expected despite the heavy sludge applications
and high organic-C in the surface soil; generally, more Cd was
extracted by DTPA than Cu, Ni, or Zn. However, the extractabi1ity
of metals varied with soil depth; more Cu, Ni, and Zn were
extracted from the surface than subsurface soils. While the
percent of total Ni and Zn extracted was higher in the surface
soils of the treated plot compared to the control plot, the
opposite was true for Cd and Cu. It must also be noted that,
for reasons unknown, a higher percentage of total Cd was
*It was assumed that continuing application rates would be at
half the annual average.
93
-------
TABLE 30. CONCENTRATIONS OF TOTAL AND DTPA-EXTRACTABLE METALS IN
COMPOSITE SURFACE AND SUBSURFACE SAMPLES
FROM COLUMBUS, INDIANA*
Soil
Depth
- cm -
Treated:
0-30
30-46
46-61
61-91
91-122
Control :
0-30
30-46
46-61
61-91
91-122
Total t
Cd
4.37
0.39
0.41
1.46
1.75
0.78
0.49
0.49
1.57
2.00
Cu
-
185
19.7
17.9
21.7
19.4
20.3
18.8
15.7
9.65
5.91
Ni
- vg/g -
521
41.1
31.9
38.4
42.0
30.0
34.5
32.4
32.8
32.1
Zn
-
625
70.0
57.0
57.0
51.3
80.6
75.0
61.7
35.5
22.3
Pb
190
24.9
16.4
21.6
51.0
21.9
19.8
15.8
19.5
22.6
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
Cd
74(16. 9)#
22(56.4)
17(41.5)
13(8.9)
20(11.4)
19(24. 4)#
14(28.6)
13(26.5)
12(7.6)
10(5)
DTPA-Extractable
Cu
- - ug/9
21.40(11.6)
2.25(11.4)
1.44(8.0)
1.84(8.5)
1.64(8.5)
2.58(12.7)
1.90(10.1)
1.55(9.9)
0.70(7.3)
0.40(6.8)
Ni
- -
60.4 (11.6)
2.67(6.5)
1.51(4.7)
2.85(7.4)
2.72(6.5)
1.73(5.8)
1.46(4.2)
1.20(3.7)
0.93(2.8)
0.69(2.2)
Zn
59.1 (9
2.02(2
1.54(2
1,79(3
2.11(4
1.94(2
0.80(1
0.84(1
0.49(1
0.42(1
5)
9)
7)
.1)
1)
4)
.1)
.4)
.4)
.9)
*0ven-dry weight basis.
tHN03-HCl04 digestion.
#Percent of total concentration.
-------
extracted from the 30- to 46- and 46- to 61-cm depth than from
other soil depths.
Plant Analyses--
Total metal analyses of corn leaves and grain from the
treated and control plots at Columbus are presented in Table 31
These analyses indicate significant increases in the concentra-
tion of Cd, Cu, Ni, and Zn in corn leaves apparently due to
sludge applications over the years while, except for slightly
elevated Cd levels, metal concentrations in corn grain showed
practically no increase. The metal concentrations were
relatively low and fell well within the ranges reported for
edible crops.
Microbiology--
No intestinal parasite ova, Salmonella sp. or Shige11 a
were detected in any of the sludge samples. Concentrations
FC and FS appeared typically to those associated with similar
sewage sludges.
In the treated plot, approximately one log reduction of FS
appeared per 20-cm depth increase; no particular significance
can be attached to the absence of FC organisms in the treated
and control soils for the Columbus site.
The leaf tissue was not positive for either Salmonella sp.
or Shigella sp. As with the soils, the presence of FS in low
concentration may indicate animal contamination by aeolian
transport of dust containing the organisms. No helminth ova
would be expected on leaf tissue unless mature corn was sprayed
with sludge or there was incidental avian dispersal of sludge.
Sludge, Soil, and Plant Conclusions--
Sludge spreading practices have resulted in significant
enrichment of surface soils with Cd, Cu, Ni, Zn, and Pb.
The heavy metals (Cu, Cd, Zn, and Pb) have not moved in
the soil profile much beyond the depth of incorporation.
Limited Ni movement is indicated by total and DTPA-
extractable analyses.
No significant heavy metal increases were observed in
corn grains.
t Although there is indication of downward migration of
Ni, soil analyses show that other metals have not moved
in measurable concentrations to depths in the soil below
30 cm. Thus, metal contamination of groundwater caused
by sludge spreading practices has probably not occurred.
95
-------
UD
TABLE 31. METAL CONCENTRATIONS IN CORN
FROM COLUMBUS, INDIANA*
Sample
Treated:
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Control :
Composite
Section 1
Section 2
Section 3
Section 4
Section 5
Mean
Std. Dev.
Cd
2.49
2.01
2.25
2.35
1.68
3.27
2.31
0.59
1.25
1.25
2.09
1.32
1.20
1.27
1.43
0.37
Cu
-
11.8
11.5
11.7
12.2
12.4
13.5
12.3
0.78
9.81
12.1
11.4
10.6
10.3
9.93
10.9
0.88
Leaves
Ni
- ng/g -
9.13
10.8
9.52
9.81
7.79
8.17
9.22
1.23
5.67
6.15
5.58
6.41
5.19
5.58
5.78
0..49
Zn Pbt
-
53.8 2.98
61.7
63.9
61.7
44.2
63.4
59.0
8.32
38.9 2.93
45.9
42.9
39.6
38.1
33.7
40.0
4.65
Cd
0.67
0.23
0.52
0.42
0.48
0.48
0.43
0.12
0.26
#
Cu
-
2.57
2.33
2.19
3.05
1.62
2.62
2.36
0.53
2.58
Grains
Ni
- yg/g -
4.01
4.90
6.29
5.66
3.77
4.03
4.93
1.07
6.64
Zn Pb+
-
24.7 1.34
27.5
29.7
34.0
27.4
27.4
29.2
2.86
29.80 1.40
*0ven-dry weight basis.
tLead was analyzed on composite
#No individual samples.
only.
-------
The Cd corn grain levels were slightly elevated
relative to the control, but still within previous
reported values considered normal.
The Cd corn leaf concentrations were statistically
significantly higher than the control leaves, the
difference being 0.88 yg/g. Similarly, Ni and Zn showed
significant differences of 3.44 and 18.94 yg/g,
respectively.
97
-------
TABLE 32. CHEMICAL COMPOSITIONS OF
SLUDGES FOR ALL SITES
Element
Range
Mean
Median
Vol. Solids
NH4-N
Organic-N
P
K
Na
Ca
Mg
Cl
Cr
Cu
Fe
Mn
Ni
Pb
Zn
H20
N03-N
S04
Ag
As
B
Cd
Co
Cr
Cu
Fe
Hg
Mn
Mo
Ni
Pb
Se
Zn
PH
Cd/Zn
36.1
0.276
1.48
1.23
0.131
0.195
1.39
0.359
0.25
0.015
0.039
0.692
0.020
0.002
0.004
0.074
85.6
0.41
8.6
0.95
1.13
32.1
5.70
6.17
150
390
6920
1.93
200
6.60
20
40
4.23
740
6.3
0.0002
- 74.7
- 4.18
- 4.50
- 3.55
- 0.535
- 0.798
- 6.25
- 1.23
- 1.09
- 0.399
- 0.714
- 4.81
- 0.987
- 0.05
- 0.748
- 4.58
- 98.3
- 60.0
- 348
- 10.2
- 6.21
- 72.0
- 1500
- 24.9
- 3990
- 7140
- 48100
- 49.0
- 9870
- 45.5
- 500
- 7480
- 17.2
- 45800
- 8.3
- 0.698
51.1
1.28
2.83
1.72
0.283
0.481
3.53
0.700
0.36
0.156
0.148
1.76
0.143
0.015
0.110
0.722
93.0
. . . q/q . . . .
19.3
95.4
3.21
3.08
46.9
185
13.9
1560
1480
11760
13.6
1430
18.5
150
1110
8.51
7220
7.58
0.084
52.4
1.01
2.46
1.56
0.222
0.611
2.78
0.585
0.275
0.127
0.082
1.35
0.045
0.008
0.015
0.177
93.8
13.0
81.7
1.95
2.52
42.5
11.2
9.68
1270
820
13500
9.82
450
11.1
80
150
7.02
1770
7.50
0.007
98
-------
SECTION II - GENERAL EVALUATION
Sludge Characteristics
A summary of information on the sewage treatment plants
supplying sludges to the case study sites was presented in
Table 8. The size of the secondary treatment plants ranged
from small to moderately large; the largest served a population
of 135,000 with an average flow of 75,700 cu m/day and the
smallest, a population of 9,200 with an average flow of 6,000
cu m/day.
Constituent concentration levels found in the sludges
analyzed are thought to be influenced by a host of synergistic
factors such as:
Background water supply,
Type and percent of contributions by industry
to the treatment plant,
0 Degree and nature of pretreatment by industry,
Wastewater treatment processes and chemicals
used, and
t Method of sludge stabilization.
In several instances, there appeared to be an inverse
relationship between treatment plant size and chemical composi-
tion of sludge produced. For example, the sludge from Frankfort,
Indiana (population 15,000) had a much higher concentration of
Cd (1,500 yg/g) than did that from Springfield, Ohio (popula-
tion of 135,000). Similarly, the Zn concentration of sludge
from Wilmington, Ohio with a population of 10,000 was 45,800
yg/g, much greater than other treatment plants serving larger
populations. This relationship is believed due to the larger
impact of a major heavy metal industrial contributor on a small
system as contrasted to its impact on a larger sewerage system.
There were no discernible differences in metal concentra-
tions in the sludge from an activated sludge plant as opposed
to a trickling filter treatment facility. The chemical composi-
tion of the sludges obtained from the nine treatment plants
(Table 32) fall within the broad range of those normally reported
for sludges (Page, 1974; and Sommers, 1977). Median concentra-
tion results reported herein are reasonably representative of
median concentrations for sludges in general, although the mean
concentrations of Co, Cd, Hg, Mo, Se, and Zn at the case study
sites were considerably greater. This is due to the high
concentrations of:
Co from Macon, Georgia (21.3 yg/g); Kendallville
(24.9 yg/g) and Columbus, Indiana (24.1 yg/g);
99
-------
Cd from Frankfort, Indiana (1500 yg/g);
Hg from Las Virgenes, California (49 yg/g); and
Chippewa Falls, Wisconsin (24.1 yg/g);
Mo from Springfield, Missouri (43.4 yg/g); and
Wilmington, Ohio (45.5 yg/g);
Se from Macon, Georgia (13.7 yg/g); and
Kendallville, Indiana (17.2 yg/g); and
Zn from Wilmington, Ohio (4.58 percent).
As shown in Table 33, the Cd to Zn ratio of the sludges
ranged from 0.0002 to 0.698.
TABLE 33. SLUDGE Cd/Zn RATIOS - ALL SITES
Cd/Zn
Macon, Ga 0.007
Las Virgenes, CA 0.008
Wilmington, OH 0.0002
Springfield, MO 0.017
Chippewa Falls, WI 0.006
Hopkinsville, KY 0.005
Frankfort, IN 0.698
Kendallville, IN 0.007
Columbus, IN 0.008
There are a number of federal and state guidelines which
specify limits on the quantities of sludge which can be applied
to agricultural lands; quantity limits are based upon constituents
in sludge considered hazardous to the health of humans and
animals, which may adversely affect the growth of crops, or which
may degrade the quality of surface or groundwaters. The compo-
nents in sludges usually considered detrimental are N, P, B,
soluble salts, trace metals (principally Cd, Cr, Cu, Pb, Zn,
Ni, and Hg), certain organics, and pathogenic bacteria and
viruses.
For agricultural utilization, annual loading rates are
usually based upon providing an adequate supply of available
nitrogen for the crop grown. Only part of the organic nitrogen
in sludge is mineralized to available forms during the cropping
season; in addition, a portion of the ammoniacal-N is volatilized
and lost to the atmosphere. After application to land, estimates
OT available N in sludge are based upon some assumed values of
100
-------
the organic-N mineralization rate and NH4-N volatile loss. The
data in Table 34 show the quantities of each sludge needed to
supply nitrogen at an annual rate equivalent to 200 kg available
N/ha, assuming 1) 20 percent availability of organic-N, and
2) a 50 percent loss of NH4-N. In terms of this particular
criterion for the sludges obtained for this study, the annual
sludge application rates would vary from a low of 6.8 to a high
of 46.1 dry m tons/ha.
The data in Table 34 also show the quantities of P and
metals which would be applied each year if the sludges were
applied at the above-mentioned rate of 200 kg available N/ha
under the assumed conditions. The data show considerably more
phosphorus would be applied than normally needed; rates of
phosphorus applied in commercial agriculture rarely exceed 80
kg P/ha. Quantities of metals applied vary greatly, e.g., Cd
from 0.07 to 36.2,and Zn from 9.2 to 568 kg/ha. Guidelines for
Cd normally specify a maximum annual loading rate somewhere
between 0.2 and 2 kg Cd/ha. Of the sludges surveyed, two treat-
ment plants (Frankfort and Kendallvi1le, Indiana) would add more
Cd annually than is considered permissible if application rates
were based upon available N.
Recommended maximum loading rates for metals (Table 35)
have been suggested (USDA, 1974, and Knezek and Miller, 1976).
Table 36 presents the maximum quantity of each sludge which could
be applied and not exceed suggested metal loading limits. The
table also shows the number of years each sludge could be applied
at the assumed N rates before cumulative metal loading would be
considered limiting. Utilizing the limits recommended by two
groups of researchers (Knezek and Miller, 1976) as a point of
reference, the data show maximum quantities of sludge which could
be applied are limited in certain cases by Cd, Cu, Ni, and Zn.
Zn would first become limiting for sludges from Springfield,
Missouri; Wilmington, Ohio; Hopkinsvi11e, Kentucky; and Kendall-
ville, Indiana; Cu for sludges from Macon, Georgia; Las Virgenes,
California; and Chippewa Falls, Wisconsin; Cd for sludge from
Frankfort, Indiana; and Ni for sludge from Columbus, Ohio. These
same calculations indicate that sludges from Wilmington, Ohio,
Kendallville and Frankfort, Indiana, could only be applied to the
same parcel of land for 2, 3, and 0 years, respectively, accord-
ing to these guidelines. The Frankfort, Indiana, si udge seems
unfit for utilization on agricultural land. The remaining
communities' sludges based upon the above N requirements would
be considered acceptable for agricultural use on the same parcel
of land for periods of 24 years or more.
Data presented in Table 37 show estimates of the total and
annual quantities of sludge and metals applied to each of the
soils from the selected sites. The computations for total metal
101
-------
TABLE 34. QUANTITIES OF SLUDGE, P, AND METALS APPLIED,
BASED UPON AVAILABLE N FOR CROPS
o
ro
Annual Loadln
Rate*
m tons/ha
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
16.
18.
12.
6.
12.
31.
24.
46.
12.
7
9
4
8
9
4
1
1
5
9 p
205
323
440
118
173
490
378
650
166
Cd
0.2
0.21
0.14
0.38
0.09
0.24
36.2
2.3
0.07
Cr
18.9
2.8
27.8
16.5
16.4
11.9
96.2
92.7
5.1
Annual
Cu
16.0
18.0
5.1
5.6
17.7
17.3
172
33.6
4.9
Applicat
Ni
kg/ ha
2.3
0.94
0.37
2.0
0.26
1.9
12.0
3.7
2.0
ion Rate
Pb
10.2
0.76
13.8
1.0
1.3
2.8
6.0
344
1.3
Mo
0.24
0.19
0.56
0.30
0
0.35
0.16
0.31
0.26
Se
0.23
0.14
0.05
0.06
0.10
0.20
0.14
0.79
0.08
Zn
29.6
25.5
568
22.5
15.4
46.2
51.8
331
9.2
*To supply the equivalent of 200 kg available N per hectare.
-------
o
CO
TABLE 35. TOTAL AMOUNT OF SLUDGE METALS
ALLOWED ON AGRICULTURAL LANDS*
Metal
Pb
Zn
Cu
Ni
Cd
Soil Cation
0-5
Maximum
500
250
125
50
5
Exchange Capacity (meq/100 g
5 - 15
Amount of Metal (Ib/acre)
1000
500
250
100
10
> 15
2000
1000
500
200
20
*Knezek and Miller, 1976.
tDetermined by the pH 7 ammonium acetate procedure.
-------
TABLE 36. MAXIMUM QUANTITIES OF SLUDGE PERMITTED,
BASED ON RECOMMENDED METAL LOADING LIMITS*
Source
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
Cd
1,848
1,982
1,964
392
3,129
2,895
14.6*
441
3,860
Maximum Total
Based on Metal
Cu Ni
573*
579*
1,341
671
401*
1,000
77
753
1,410
. m tons/h
1,571
4,400
7,333
733
11,000
3,667
440
2,750
1,375*
Sludge
Loading
Pb
Id . .
3,607
55,000
1,982
14,667
22,000
24,444
8,800
294
22,000
Zn
621
815
24*
332*
924
748*
512
153*
1,486
No. of Annual Sewage
Applications Permittedt
Cd Cu Ni Pb Zn
111
105
158
58
242
92
0*
10
309
34*
31*
108
99
31*
32
3
16
113
94
233
591
108
853
117
18
60
110*
216
2,910
160
2,157
1,705
778
365
6
1,760
37
43
2*
49*
72
24*
21
3*
119
*Knezek and Miller, 1976 (see Table 35).
tBased upon loading rates required to yield 200 kg available N per hectare, and limits on metal loading
suggested by NC 118 Regional Technical Committee (see Table 35).
#
Limiting value.
-------
TABLE 37. ANNUAL AND TOTAL LOADING RATES OF SLUDGE AND HEAVY METALS
Average
Annual Sludge
Application
Rate-
Dry Weight
(m tons/ha)
Average
Annual Metal Loading
Rate
Cd Cu Ni Zn Pb
(Kg/ha)
Total Sludge
Application
Dry Weight
(m tons/ha)
Total Metal Loading
Cd Cu Ni Zn
(Kg/ha)
o
en
Pb
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
28*
50t
6.8*
15t
16*
22*
30t
19. 7#
65t
0.3
0.6
0.08
0.88
0.11
0.17
45
1.0
0.37
27
48
2.8
13
22
12
214
14.4
25
3.9
2.5
0.2
4.7
0.3
1.4
15
1.6
10
50 17
68 2
311 7.5
52 2.4
19 1.6
32 2.0
65 7.5
142 147.
48 7.8
308*
149
116*
237
80*
66*
360*
81*
326
3.3
1.6
1.3
13.3
0.56
0.5
540
4.1
1.9
297
142
47
194
110
36
2570
59
125
43
7.5
3.4
71
1.6
4.2
180
6.5
50
550
201
5290
784
95
96
774
582
239
189
6
128
36
8
6
90
605
39
* Estimated
tAifnual amount computed from multi-year average,-. -Data shown represents last 3 years of spreading.
#1975
-------
loading are based upon the assumption that the composition of
sludge in prior years was comparable to that in 1975. In most
cases, more sludge has been applied than would be needed to
supply sufficient available N (compare Tables 36 and 37). Quan-
tities of Cd applied annually, except for the Frankfort, Indiana
site, fall within the range of 0.08 to 1.0 kg/ha; in terms of
total metal loading, recommended limits have already been exceeded
for Zn applied at Wilmington, Ohio , and Cd and Cu applied at
Frankfort, Indiana. As has been discussed, there is no perceiv-
able impact due to Zn at the Wilmington site, and there 1s some
question about the validity of the extrapolated Zn value. The
sludges have been applied for periods which range from 5 to 17
years; and with the exception of those noted above, total maximum
metal loadings are still within suggested limits.
Table 38 presents a comparison of sewage sludges evaluated
in terms of current fertilizer costs. The sludges from Wilmington,
Ohio and Springfield, Missouri had the greatest economic value
at $40.18 and $30.38/dry m ton, respectively; the Kendal1vi1le,
Indiana sludge, the least at $16.01/dry m ton.
Soil
Total Metals--
A summary of the trace metal concentrations of surface and
subsurface soils is presented in Tables 39 and 40. For all sites
surveyed, the data show statistically significantly greater
concentrations of Zn in the treated surface soil compared to the
control and significantly higher surface than subsurface concen-
trations. This is due no doubt to the much higher concentrations
of Zn in sludge than in soil. Cu concentrations, except for the
Springfield, Missouri site, and Ni concentrations, except for the
Wilmington, Ohio and Chippewa Falls, Wisconsin ..sites, are like-
wise significantly greater in the surface than in subsurface
soil. Five of the nine sites surveyed (Macon, Georgia; Spring-
field, Missouri; Hopkinsvi1le, Kentucky; Frankfort, Indiana; and
Columbus, Indiana) showed significantly higher concentrations of
Cd in surface as compared to subsurface soils.
It should be noted, however, that while these soil metal
concentrations are elevated, in most instances they do not exceed
normal ranges for soils in the U.S. The total concentrations
of metals in surface soils from all plots are in the range
considered normal for soils in general. Sludge spreading opera-
tions at Macon, Georgia, and Columbus, Indiana, have produced
atypically high concentrations of Zn in the surface soil.
Similarly, concentrations of Cd in the surface soils from the
treated plots at Macon, Georgia, Las Virgenes, California,
Frankfort and Columbus, Indiana; of Cu at Macon, Georgia and
Columbus, Indiana? and of Ni at Columbus, Indiana are greater
than those usually observed (Table 41). Although the concentra-
tion of Cd in the surface soil from the Las Virgenes site is
106
-------
TABLE 38. COMPARATIVE ECONOMIC VALUES FOR SEWAGE
SLUDGE AS A FERTILIZER SOURCE*
Site
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
Nt
kg/m ton
12.4
10.6
10.7
29.5
15.5
6.36
8.30
4.34
10.95
$/m ton
5.46
4.66
4.68
12.98
6.82
2.80
3.65
1.91
4.82
p#
kg/m ton
12.3
17.1
35.5
17.4
13.4
15.6
15.7
14.10
13.30
$/m ton
12.30
17.10
35.50
17.40
13.40
15.60
15.70
14.10
13.30
Total
$/m ton
17.76
21.76
40.18
30.38
20.22
18.40
19.35
16.01
18.12
*kg/m ton units expressed on an oven-dry weight basis.
tN calculated at a current value of $.44/kg-N
P calculated at a current value of $1.00/kg-P
107
-------
TABLE 39. SOIL METAL CONCENTRATIONS IN SAMPLE MEANSt
Site
o
00
Cd
Death Treat. Contr.
Cu
Treat. Contr.
Ni
Treat. Contr.
Zn
Treat. Contr.
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Surface
20-46
46-61
61-91
91-122
Surface
30-61
61-91
91-122
Surface
18-30
30-61
61-91
91-122
Surface
18-30
30-61
61-81
81-122
Surface
20-46
46-61
61-91
91rl22
4.98*
0.86
0.41
0.31
0.96
4.00
3.14*
3.33
3.34*
0.95
0.78*
0.83*
0.94*
1.06
1.12*
0.71
0.74
0.83
0.81
0.44
0.39
0.32
0.33
0.34
0.55
0.58
0.38
0.42
0.96
3.88
3.72
3.65
3.95
0.87
0.92
1.04
1.15
1.09
0.75
0.67
0.73
0.84
0.87
0.44
0.39
0.35
0.39
0.37
283*
14.9
5.99
5.83
20.1
45.9*
29.2*
28.2
28.5*
15.9*
18.7
21.8
23.4
23.0*
21.1
12.4*
14.3
16.3
18.0
18.0*
10.2*
13.1
14.2
13.6
. . . nQ/
12.1
9.8
5.4
5.7
21.0
27.2
26.7
27.3
26.6
14.3
17.5
22.5
23.2
24.6
25.2
15.1
12.9
13.9
15.8
.7.4
8.1
11.3
14.8
13.6
'q . . . .
68.8*
16.50
7.46
6.25
24.7
53.3*
50.7
49.4
50.1
24.3
35.0
37.6
42.2*
39.7*
30.1*
23.1*
26.7
27.5
35.3
14.6
13.9
15.2
14.4*
17.5
18.7
12.7
9.60
9.49
25.4
59.8
49.3
48.7
48.5
25.1
31.4
39.7
45.44
44.6
21.8
20.9
24.0
31.1
34.7
14.2
13.3
16.7
18.8
15.6
536*
95.5*
29.2*
28.0*
90.8*
128
97.0
92.4
92.4
139*
61.0
66.8*
65.5*
64.5*
103*
45.0*
50.8*
44.7
56.8
48.0*
25.9
23.3
20.4
17.5
31.7
26.1
18.1
16.5
57.8
97.1
95.6
96.2
91.1
49.2
58.9
79.0
72.5
71.4
39.3
35.0
42.2
51.1
56.4
31.4
23.3
21.9
23.6
22.6
indicates, with 90% confidence, that means of treated vs control plots have significant statistical
differences.
* Digestion: all data expressed on oven dry weight basis.
-------
TABLE 39 (continued)
Site Depth
Hopkinsville, KY Surface
15-30
30-61
61-91
91-122
Frankfort, IN Surface
15-40
40-61
61-91
91-122
_^ Kendallville, IN Surface
o 20-30
10 30-61
61-91
91-122
Columbus, IN Surface
30-46
46-61
61-91
91-122
Treat.
1.18*
0.96*
0.68
0.84
0.62*
13.1 *
2.36*
1.08*
0.92
0.82
0.36
0.15*
0.30
0.47
0.73
3.52*
0.43*
0.41
0.78*
1.30*
Cd
Contr.
0.78
0.75
0.72
0.89
0.70
0.92
0.78
0.77
0.91
0.87
0.20
0.26
0.29
0.68
0.61
0.70
0.66
0.48
1.54
1.80
Treat.
27.7*
17.7*
18.4*
15.4
15.7
29.8*
16.0
19.3
20.2
22.3
22.9*
20.8*
20.8
21.0
19.4
162*
19.9
17.2
20.3*
16.5*
Cu
Contr.
9.5
12.6
17.0
15.2
15.9
10.7
16.5
20.4
21.5
23.6
11.7
15.3
20.2
19.6
18.2
19.5
20.8
16.3
10.8
7.2
Treat.
q/q . . .
25.1*
27.5*
39.6
25.7
36.3
26.1*
25.0*
35.5
36.5
37.0*
28.7*
37.2*
46.4*
48.5*
49.5*
496*
38.0
32.7
38.3
38.2*
Ni
Contr.
20.7
25.3
38.4
26.4
36.4
20.2
32.5
36.9
40.2
47.3
22.3
28.7
38.5
44.1
41.8
30.7
33.6
31.3
32.8
33.1
Treat.
110*
68.3
57.2
60.7*
60.4*
85.3*
63.9*
58.8
58.6
58.6
118*
70.7*
67.3
67.8
65.7
555*
68.1*
57.8
54.3*
43.1*
Zn
Contr.
49.2
64.4
60.0
73.0
80.1
50.5
55.1
57.1
56.3
56.4
58.5
62.5
66.8
63.6
58.4
81.8
76.4
62.4
36.0
23.2
indicates, with 90% confidence, that means of treated vs control plots have significant statistical
difference.
-------
TABLE 40. TOTAL METAL CONCENTRATIONS IN SURFACE SOILS*
Element/Plot
Cd Treated
Control
Cu Treated
^ Control.
o
N1 Treated
Control
Zn Treated
Control
Macon,
Georgia
Mean
Std. Deviation
4.98
0.66
0.55
0.18
283
33.3
12.1
2.91
68.8
10.9
18.7
3.72
536
46.5
31.7
8.02
Las Virgenes,
California
Mean
Std. Deviation
4.00
0.69
3.88
0.29
45.9
8.06
27.2
0.85
53.3
0.90
49.8
0.87
128
11.2
97.1
3.68
Wilmington,
Ohio
Mean
Std. Deviation
0.95
0.19
0.87
0.04
15.9
1.13
14.3
1.37
24.3
1.97
25.1
2.22
139
37.7
49.2
2.59
Springfield,
Missouri
Mean
Std. Deviation
1.12
0.10
0.75
0.06
21.1
2.04
25.2
4.71
30.2
5.54
21.8
0.83
103
5.58
39.3
1.31
Chippewa Falls,
Wisconsin
Mean
Std. Deviation
0.44
0.06
0.44
0.06
18.0
2.69
7.42
0.31
14.6
0.77
14.2
0.64
48.0
1.84
31.4
1.26
*HN03-HC104 Digestion; all data expressed on oven dry weight basis.
-------
TABLE 40 (continued)
Element/Plot
Cd
Cu
Ni
Zn
Treated
Control
Treated
Control
Treated
Control
Treated
Control
Hopkinsville,
Kentucky
Mean
Std. Deviation
Frankfort, Kendallville,
Indiana Indiana
Mean Mean
Std. Deviation Std. Deviation
na/a
Columbus,
Indiana
Mean
Std. Deviation
1.18
0.44
0.78
0.07
27.7
4.02
9.52
0.93
25.1
0.42
20.7
1.65
111
4.16
49.2
2.25
13.1
7.47
0.92
0.02
29.8
5.06
10.7
0.50
26.1
3.03
20.2
1.01
85.3
12.1
50.5
1.71
0.36
0.21
0.20
0.08
22.9
2.75
11.7
0.28
28.7
1.85
22.3
1.04
118
20.3
58.5
2.99
3.52
0.56
0.70
0.08
162
14.6
19.5
1.16
496
64.2
30.7
1.24
556
56.3
81.8
3.41
*HN03-HC104 Digestion; all data expressed on oven dry weight basis.
-------
TABLE 41. COMPARISON OF METAL CONCENTRATIONS IN SLUDGE TREATED
SOILS WITH CONCENTRATIONS CONSIDERED TYPICAL FOR SOILS
Site
Concentration in Treated Plot Surface Soils from All Si
Cd Cu Ni Zn pH
ites
CEC
Macon, 6A
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
* t
Typical Range ''
5.0
4.0
1.0
1 .1
0.4
1.2
13.1
0.4
3.5
0.1-0.5
283
45.9
15.7
21.1
18.0
27.7
29.8
22.9
162
20-40
68.8 536
53.3
24.3
30.2
14.6
25.1
26.1
28.7
490
40-80
128
139
103
48.0
111
85.3
118
556
50-100
3.7
6.5
6.5
7.0
5.5
6.2
6.7
6.4
6.6
17
30
30
18
10
31
30
27
30
*Bowen, 1966
fAllaway, 1968
-------
higher than that considered typical for soils, the source is of
natural origin, since Cd concentrations in soil from the control
and treated plots are approximately the same, and the concentra-
tions in treated and control plots are uniform at all depths
sampled (Burau, e_t aJL 1973).
The data in Table 39 also reflect significant differences
between treated and control plots which are probably due to
natural variation in soils rather than to sludge spreading
operations. For example, concentrations of Cd in soils at two
depths from the treated plot at Las Virgenes, California and
three depths at Wilmington, Ohio: and Columbus, Indiana are
markedly less than concentrations for soils at comparable depths
from the control plots. Ignoring possible natural variation,
the data at a few sites show evidence that metals may have
migrated in the soil profile beyond the depth of incorporation.
At the Macon, Georgia treated site, the data show evidence of
movement on Zn to a depth of at least 1.2 m; the soil at this
site is very sandy, and conditions would be most conducive to
metal movement. It is generally thought that movement of metals
is enhanced by acid soils and coarse texture. Since the water
table is at 1.5 m, this site is probably one where sludge spread-
ing operations should not be practiced. Limited movement of Zn
at the Springfield, Missouri and Columbus, Indiana, treated
sites; of Ni at Springfield, Missouri, Hopkinsvi1le, Kentucky, and
Kendal1vil1e, Indiana, treated sites; and of Cu at Las Virgenes,
California, Hopkinsvi11e, Kentucky, Kendallville and Columbus,
Indiana, treated sites is also indicated. Overall, however, the
data indicate that movement of metals in the soil profiles,
except possibly for Zn at the Macon, Georgia site,is quite
restricted.
A summary of the range, median, and mean concentration for
surface soils from the treated and control plots is presented
in Table 42. The minimum and maximum soil concentrations of the
metals Cd, Cu, Zn, and Pb from the treated plots exceed those
for the control plots. Likewise, median and mean concentrations
of metals in soils from the treated plots are greater than those
from the control plots. Treated plot median metal concentrations
in soils are, except for Zn, less than the maximum metal concen-
trations for the control plots. This affirms that sludge spread-
ing operations, if properly designed and managed, need not exceed
typical metal concentrations in soil.
Individual section soil composite samples, as well as five-
section composites from the treated and control plots at each
location, were analyzed. The data presented in Table 43 for plot
composites are in general agreement with those for means of
individual samples presented in Table 39. The data show that
metal enrichment in the treated plots is, in most instances,
restricted to the surface soil. There is an indication of some
movement of Cd to the 30-cm depth sampled in the treated plots at
113
-------
TABLE 42. TOTAL METAL CONCENTRATIONS IN COMPOSITE SURFACE SOILS FOR ALL SITES*
Element Plot
Cd Treated
Control
Cu Treated
Control
Ni Treated
451 Control
Zn Treated
Control
Pb Treated
Control
Ran
0.42 -
0.29 -
10.5 -
7.60 -
14.20 -
15.2 -
49.3 -
27.7 -
9.90 -
8.50 -
ge
12.9
3.77
267
27 .7
521
48.0
625
98.1
325
35.0
Median
1.33
0.78
26.3
11.9
26.5
20.6
113
49.5
32.9
19.9
Mean
3.45
1.05
68.8
15.3
87.3
24.3
208
53.2
80.6
21.3
*HN03-HC104 Digestion.
-------
TABLE 43. METAL CONCENTRATIONS OF TREATED AND CONTROL SOIL COMPOSITES*
Site
Mac on, GA
Las
Virgenes,
CA
Wilmington,
z; OH
CJl
Spring-
field, MO
Chippewa
Falls, WI
Depth
(cm)
Surface
20-46
46-61
61-91
91-122
Surface
30-61
61-91
91-122
Surface
18-30
30-61
61-91
91-122
Surface
18-30
30-61
61-81
81-122
Surface
20-46
46-61
61-91
91-122
Treat.
5.89
0.96
0.47
0.33
0.99
3.58
3.79
3.41
3.53
0.86
0.89
0.77
1.00
1.10
1.17
0.77
0.82
0.83
0.77
0.42
0.38
0.35
0.31
0.44
Cd
Contr.
0.76
0.63
0.51
0.40
0.95
3.77
3.75
3.22
4.11
0.87
0.91
1.08
1.08
1.06
0.73
0.68
0.70
0.82
0.89
0.46
0.34
0.48
0.31
0.33
Treat.
267
13.3
10.1
6.93
19.6
45.4
29.1
28.5
28.5
16.0
19.0
22.2
22.8
23.0
10.5
13.1
15.7
20.0
16.1
17.4
10.5
11.3
13.0
18.5
Cu
Contr.
11.9
10.5
6.00
6.56
20.4
27.7
27.6
28.0
28.1
14.6
17.6
21.5
23.4
24.8
23.6
14.3
12.0
13.2
15.0
7.6
7.6
12.2
15.7
13.8
Treat.
67.6
17.1
9.44
12.5
24.4
52.9
50.3
49.5
50.2
24.7
32.3
39.0
44.3
41.8
28.9
28.2
47.6
38.7
35.8
14.2
16.7
16.1
14.6
14.4
Ni
Contr.
UQ/O . .
19.1
13.6
12.3
13.4
24.0
48.0
50.5
50.2
52.8
24.9
31.4
42.3
46.2
44.5
19.9
22.7
24.4
28.8
34.4
15.2
14.3
18.3
19.6
16.3
Treat.
475
80.4
39.0
27.5
88.5
120
93.4
93.8
90.7
190
62.5
65.1
66.0
67.8
108
41.8
48.8
52.9
57.6
49.3
29.4
21.8
22.1
24.7
In
Contr.
27.7
25.1
15.5
15.3
52.4
98.1
94.2
90.2
90.9
49.5
57.3
75.0
74.2
71.3
36.8
34.8
39.2
45.7
48.0
31.3
24.2
30.2
27.8
19.5
Treat.
325
35.4
19.4
13.9
49.6
21.7
19.3
19.0
18.7
47.8
23.5
22.8
20.0
21.4
40.2
21.4
25.8
28.0
25.1
9.9
4.4
4.0
2.4
2.7
Pb
Contr.
35.0
28.5
16.8
13.1
38.9
19.9
19.7
19.9
20.6
24.6
22.1
22.7
21.9
20.1
34.0
24.1
22.1
20.6
26.1
8.5
5.7
5.6
4.0
2.1
Digestion. All data expressed on oven dry weight basis.
-------
TABLE 43 (continued)
Site
Hopkins-
ville, KY
Frankfort,
IN
Kendall -
ville, IN
Columbus,
IN
Depth
(cm)
\ ** /
Surface
15-30
30-61
61-91
91-122
Surface
15-40
40-61
61-91
91-122
Surface
20-30
30-61
61-91
91-122
Surface
30-46
46-61
61-91
91-122
Treat.
1.33
0.95
0.69
0.84
0.63
12.9
2.17
1.05
0.92
0.83
0.52
0.16
0.25
0.46
0.60
4.37
0.39
0.41
1.46
1.75
Cd
Contr.
0.83
0.77
0.78
1.02
0.68
0.92
0.75
0.80
0.79
0.84
0.29
0.22
0.28
0.55
0.51
0.78
0.49
0.49
1.57
2.00
Treat.
26.3
17.7
18.2
15.4
15.4
30.0
15.1
19.1
19.1
22.7
21.8
19.6
21.0
21.3
19.7
185
19.7
17.9
21.7
19.4
Cu
Contr.
9.8
13.7
16.8
15.4
15.4
10.6
15.5
20.9
22.0
22.7
11.5
14.6
19.9
19.4
18.5
20.3
18.8
15.7
9.65
5.91
Treat.
24.8
27.0
39.2
26.3
35.4
25.5
24.5
34.6
34.3
38.5
26.5
37.3
44.9
44.6
43.4
521
41.1
31.9
38.4
42.0
Ni
Contr.
U O/Q . . ,
21.5
25.6
37.2
26.8
36.4
19.9
32.6
37.8
42.0
44.5
20.6
28.2
38.0
40.6
37.7
30.0
34.5
32.4
32.8
32.1
Treat.
109
68.0
55.0
60.4
60.1
88.0
61.6
57.0
56.1
59.1
113
64.8
67.0
65.7
63.9
625
70.0
57.0
57.0
51.3
Zn
Contr.
50.2
62.3
64.0
71.6
78.0
49.2
54.0
60.8
57.2
55.3
55.0
60.3
66.9
61.9
57.6
80.6
75.0
61.7
35.5
22.3
Treat.
30.2
17.7
23.2
16.0
24.2
27.8
16.9
17.9
19.9
18.4
32.9
12.9
13.0
13.0
14.5
190
24.9
16.4
21.6
51.0
Pb
Contr.
19.5
18.0
39.4
15.3
23.6
17.2
21.0
21.0
17.3
18.2
11.3
11.0
12.2
12.3
12.8
21.9
19.8
15.8
19.5
22.6
-------
Macon, Georgia and Hopklnsvil1e, Kentucky; and to a depth of
61 cm at Frankfort, Indiana. No consistent evidence of movement
of either Cu, Ni, or Pb beyond the depth of incorporation is
apparent in any of the sludge treated soils. The data suggests
limited movement of Zn beyond the depth of incorporation in soils
from the treated sites at Macon, Georgia; Springfield, Missouri;
and Frankfort and Kendal1vi11e, Indiana.
DTPA-Extractable Metals--
The concentrations of metals (Cd, Cu, Ni, and Zn) extracted
from surface soils with diethylenetriaminepentaacetic acid
(DTPA) are presented in Table 44. The data show results somewhat
similar to those already discussed for total metals. Generally,
metal concentrations extracted from soils of the treated plots
exceed those extracted from soils of the control plots.
Concentrations of Cu and Zn extracted from the treated soil at
Macon, Georgia are unusually high and no doubt reflect Cu and Zn
soil enrichment caused by sludge spreading. Although the Zn levels
in soils at the Wilmington, Ohio, Springfield, Missouri, and
Frankfort and Kendallville, Indiana, treated plots were expected
to exceed those at Macon, Georgia (see Table 39), the DTPA
extractables from these sites were considerably less than those
from the Macon, Georgia, site. This may be due either to the
high organic matter content or low soil pH or combination of these
soil properties at the Macon, Georgia site. The range, median,
and mean concentration of metals extracted with DTPA for the
treated and control plots are summarized in Table 45. As was
observed with total metals, the minimum and maximum, and median
and mean concentrations for treated soils exceed those from the
control plots. The median concentrations of DTPA-extractable Cd
and Cu for treated soils are less than the maximum of the range
for the controls, indicating, as previously stated for total metals,
that metal enrichment beyond levels considered normal for soils
can be controlled.
Bingham, e_t aj_. (1975) have shown that when the amount of
Cd extracted with DTPA exceeds 2.4 yg/g, a Cd phytotoxicity is
possible, particularly with sensitive plants. Using this level
as a reference point, the soil from Frankfort, Indiana at 7.70
yg/g has probably become sufficiently enriched with Cd to
adversely affect the growth of plants sensitive to excess Cd
in soil.
Plants
A summary of the types of plants, rotation cycles, and end
uses of the crops from the nine sites was presented in Table 7.
Crops grown at six of the nine sites (Macon, Georgia; Wilmington,
Ohio; Las Virgenes, California; Springfield, Missouri; Hopkins-
vine, Kentucky; and Kendallville, Indiana) were forages; all
were used as non-dairy cattle feed.
117
-------
TABLE 44. EFFECTS OF SLUDGE APPLICATIONS ON SOME SOIL PROPERTIES AND CONCENTRATIONS
OF DTPA-EXTRACTABLE HEAVY METALS IN SURFACE SOILS
00
Site
Macon, GA
Treated
Control
Las Virgenes, CA
Treated
Control
Wilmington, OH
Treated
Control
Springfield, MO
Treated
Control
Chippewa Falls, UI
Treated
Control
Hopkinsville, KY
Treated
Control
Organic
Carbon
(percent)
30.8
1.2
1.58
1.40
1.60
1.61
1.53
1.83
0.74
1.05
1.41
1.43
PH
r
3.6
4.1
6.5
7.1
6.5
6.6
7.0
6.9
5.5
5.4
6.2
5.2
Texture
sandy loam/
loamy sand
sandy loam
clay loam
clay loam
silt loam
silt loam
silt loam
silt loam
sand
loamy sand
silt loam
silty clay
loam/silt loam
DTPA
Cd
1.42
0.08
1.48
1.37
0.14
0.13
0.38
0.11
0.06
0.06
0.30
0.09
Extractables -
Cu
64.3
1.23
5.41
1.69
1.86
1.38
7.07
7.35
3.44
0.42
6.12
0.79
Surface S
Ni
13.7
0.72
2.51
1.45
0.70
.87
3.18
1.49
1.00
0.33
1.59
1.20
.oils
Zn
269
1.14
8.12
1.01
27.5
1.20
36.6
1.79
4.28
1.54
17.0
0.94
-------
TABLE 44 (continued)
Site
Frankfort, IN
Treated
Control
Kendallville, IN
Treated
Control
Columbus, IN
Treated
Control
Organic
Carbon
1.48
1.22
1.63
1.63
5.69
1.63
H
6.7
6.0
6.4
6.6
6.6
6.4
Tpxturp
silt loam
silt loam
clay loam
loam
sandy loam
clay loam
DTPA
Cd
7.70
0.18
0.27
0.17
0.74
0.19
Extractables -
Cu
. . . (lia/a)
5.75
1.24
5.92
1.50
21.4
2.58
Surface
N1
2.78
1.87
2.29
1.82
60.4
1.73
Soils
Zn
8.10
1.62
27.2
2.81
59.1
1.94
-------
ro
o
TABLE 45. CONCENTRATIONS OF DTPA-EXTRACTABLE METALS
IN COMPOSITE SURFACE SOILS FOR ALL SITES *
Element
Cd
Cu
Ni
Zn
Plot
Treated
Control
Treated
Control
Treated
Control
Treated
Control
R<
0.06
0.06
1.86
0.42
0.70
0.33
4.28
0.94
inge
.... M9/g .
- 7.70
- 1.37
- 64.3
- 7.35
- 60.4
- 1.87
-269
- 2.81
Median
0.38
0.13
5.92
1.38
2.51
1.45
27.2
1.54
Mean
1.39
0.26
13.4
2.02
9.79
1.28
50.8
1.55
Data Expressed on Oven Dry Weight Basis
-------
The following tables present the plant tissue and grain
analyses and should be used as references when reviewing the
observations that follow:
Table 46 - Mean Metal Concentrations in Leaf Tissue
Table 47 - Mean Metal Concentrations in Harvested Grains
Table 48 - Total Metal Concentrations in Plants
The Cd concentrations in forage crops grown in soils from
the treated plots at Macon, Georgia, Hopkinsvi1le , Kentucky, and
Columbus and Kendal1vil1e, Indiana were significantly greater
than similar crops grown on the soils of the control sites.
Cadmium concentrations in ryegrass grown on the control plot at
Las Virgenes, California were statistically significantly
greater than those grown on the treated plot, probably due to
the unusually high natural concentration of Cd in this soil.
Fescue grown on soil from treated and control plots at Wilmington,
Ohio and Springfield, Missouri did not contain statistically
significant Cd concentration differences.
Concentrations of Cd in grains grown on soils from the
treated plots at Chippewa Falls, Wisconsin (soybeans) and
Frankfort, Indiana (wheat) were statistically significantly
greater than the same grains, grown on the control sites. The
concentration of Cd in soil from the treated plot at Frankfort,
Indiana is unusually high and is the cause of the elevated
concentration of Cd in wheat grain grown at this site. These
grain levels are worthy of concern. Wheat is most common in the
diet of humans in the U.S., with average daily consumption of
approximately 100 gram per day (USDA 1959). Assuming that the
Cd concentration is unchanged by the wheat milling process, daily
Cd intake from this source would be 126 yg/day, which is in
excess of the maximum daily intake of 57-72 yg Cd recommended by
the World Health Organization (1972). Although there were signif-
icantly higher concentrations of Cd in plants grown on the treated
plots, only in the case of wheat at Frankfort, Indiana were the
concentrations of Cd above the normal range reported for similar
plants grown on untreated soils.
Cu concentrations in plant material grown on treated and
control plots were in the normal range and well below levels
considered indicative of phytotoxicity. Concentrations of Cu
were statistically significantly greater (treated vs control)
in the cheatgrass (Macon, Georgia), soybeans and soybean petioles
(Chippewa Falls, Wisconsin), immature wheat and wheat grains
(Frankfort, Indiana), and corn leaves (Columbus, Indiana).
Generally, Mi concentrations of plant materials from both
the treated and control plots were in the range normally found
in plant materials. The Ni concentration in cheatgrass from the
Macon, Georgia site may seem unusually high compared to plant
121
-------
TABLE 46. MEAN METAL CONCENTRATIONS IN LEAF TISSUE*
Site
Macon, GA
Las Virgenes, CA
Wilmington, OH
Springfield, MO
Chippewa Falls, WI
Hopkinsville, KY
Frankfort, IN
Kendallville, IN
Columbus, IN
Plant
Cheatgrasst
Oats
Ryegrass
Alfalfa
Fescue
Soybeans
Fescue
Wheat
Alfalfa
Corn
Cd
0.71#
0.31
0.67
1.41ff
0.88
0.85
0.34
0.43
1.38#
0.83
0.27#
0.18
0.92#
0.28
0.74*
0.60
2.31#
1.43
Cu
- - yg/g
22. 0#
5.61
11.4
10.5
8.24
9.22*
4.63
5.25
13. 3#
10.5
7.29#
4.39
6.75#
5.90
9.31
8.46
12. 3#
10.9
Ni
17. 4#
3.63
9.01#
5.08
7.37
8.27
4.38#
3.51
13.3
10.6
4.28
3.71
3.38
4.15
7.02
6.70
9.22#
5.78
Zn
383 #
31.2
58.5
61.1
40. 5#
32.4
31.3?
24. 7r
109 #
57.3
37. 6#
20.5
29.8
27.9
83. 0#
36.5
59. 0#
40.0
*HN03-HC104 digestion; oven-dry weight basis.
tFor each metal, the first value is from the treated plot; the second, from
the control plot.
Indicates a significant difference between the treated and the control with
90 percent confidence level.
122
-------
TABLE 47. MEAN METAL CONCENTRATIONS IN HARVESTED GRAINS*
Site
Chippewa Falls, WI
Frankfort, IN
Columbus, IN
Plant
Soybeans t
Wheat
Corn
Cd
0.1 3#
0.07
1.26#
0.20
0.43
Cu
- - yg/g
19. 2#
11.1
4.65
6.17#
2.36
Ni
4.06#
1.82
1.24
1.98#
4.93
Zn
96. 8#
69.6
45.1
57. 5#
29.2
digestion; data on oven-dry basis.
tFor each metal, the first value is from the treated plot; the second, from
the control plot.
#
Indicates a significant difference between the treated and the control with
90 percent confidence level.
123
-------
TABLE 48. TOTAL METAL CONCENTRATIONS IN PLANTS*
El ement/Plot
Cd Treated
Control
-P.
Cu Treated
Control
Ni Treated
Control
Zn Treated
Control
Macon,
Georgia
Mean
Std. Deviation
0.71
0.11
0.31
0.07
22.0
5.16
5.61
0.64
17.4
2.46
3.63
0.24
383
52.0
31.2
1.95.
S
Las Virgenes,
California
Mean
Std. Deviation
0.67
0.19
1.41
0.35
11.4
2.08
10.5
0.49
9.01
1.16
5.08
0.84
58.5
11.9
61.1
9.03
ITE
Springfield,
Missouri
Mean
Std. Deviation
0.34
0.05
0.43
0.34
4.62
0.28
5.25
0.20
4.38
0.51
3.51
0.20
31.3
2.52
24.7
0.66
Hopkinsville,
Kentucky
Mean
Std. Deviation
0.27
0.08
0.18
0.07
7.29
2.87
4.39
0.54
4.28
1.18
3.71
0.69
37.6
11.6
20.5
2.28
Wilmington,
Ohio
Mean
Std. Deviation
0.88
0.09
0.85
0.21
8.28
0.60
9.22
0.67
7.37
0.92
8.27
0.59
40.5-
2.56
32.4
2.S1
*HN03-HC104 Digestion; all data expressed on oven dry weight basis,
-------
TABLE 48 (continued)
Element/Plot . ,
Cd Treated
_, Control
f>O
en
Cu Treated
Control
Ni Treated
Control
Zn Treated
Control
Frankfort,
Indiana
Mean
Std. Deviation
0.92
0.28
0.28
0.08
6.75
0.27
5.90
0.29
3.38
0.68
4.15
0.70
29.8
1.49
27.9..
3.05
SITE
Kendallville,
Indiana
Mean
Std. Deviation
0.74
0.09
0.60
0.03
9.31
0.95
8.46
0.75
7.02
0.49
6.70
0.26
83
35.5
36.5
3.15
Chippewa Falls,
Wisconsin
Mean
Std. Dentation
1.38
0.57
0.83
0.22
13.3
1.59
10.5
0.65
13.3
3.04
10.6
2.80
109
26.4
57.3
5.72-
Columbus,
Indiana
Mean
Std. Deviation
2,31
0.59
1.43
0.37
12.3
0.78
10.9
0.88
9.22
1.23
5.78
0.49
59.0
8.32
40
4.66
-------
materials from other sites. However, the soil at the Macon site
is quite acid, and Ni in plant materials grown on acid soils is
commonly considerably greater than in plants grown on near
neutral, neutral, and calcareous soils.
Except for the Macon, Georgia, site, concentrations of Zn
in the plant materials are in the range considered normal. At
Macon, Georgia, the concentration of Zn in cheatgrass from the
treated plot is 383 ug/g. This is considered to be in or
approaching the phytotoxic ranges for a number of plant species.
Chlorinated Hydrocarbons
Tables 49, 50, and 51 present a summary of chlorinated
hydrocarbons in stabilized sludges, soils, and plants, respectively
Levels in the sludges generally correspond in magnitude to
published values (Furr, e_t aj_. 1976). A summary of the findings
is as follows:
PCB's--
Amounts of Aroclor 1248 were detected in the sludges at all
sites except Columbus, Indiana, with the highest concentration
at Springfield, Missouri (5087 and 2846 ppb). Aroclor 1221 was
detected only in the sludges from Macon, Georgia (5872 ppb) and
Hopkinsville, Kentucky (260 ppb).
Significant quantities of Aroclor 1248 were detected in
treated surface soils at Wilmington, Ohio: Springfield, Missouri;
and Columbus, Indiana. The concentrations were 99, 120, and
216 ppb, respectively. In each case, the PCB concentration of
the control plot was at or below the detection level (0.01 ppb).
All plant data with the exception of fescue grass at Spring-
field, Missouri, and soybeans at Chippewa Falls, Wisconsin, show
insignificant PCB levels. The concentration in these two crops,
however, was very low - 0.27 and 0.8 ppb, respectively. The
reason for the control PCB concentrations being higher than the
treated plot levels at Springfield, Missouri is not clear.
DDT--
Five of the sludges (Macon, Georgia; Springfield, Missouri;
Hopkinsville, Kentucky; and Frankfort, Indiana) contained quanti-
fiable amounts of DDT.
The DDT levels in the treated surface soils at these sites
indicate increased amounts at Macon, Georgia and Frankfort,
Indiana.
Only the treated plot ryegrass at Las Virgenes, California
showed a measurable quantity of DDT (0.28 ppb).
126
-------
TABLE 49. CHLORINATED HYDROCARBON CONCENTRATIONS
IN STABILIZED SLUDGES
Site
Macon
4/5/76
10/20/76
Las Virgenes
4/15/76
8/4/76
_ Field Dried
ro
Wilmington
7/2/76
8/25/76
Springfield
5/17/76
9/7/76
Chippewa Falls
8/3/76
11/6/76
DDT
5.85
<0.24
<0.25
<0.06
<0.07
<0.31
<0.19
1 .54
<0.26
<0.06
<0.05
Dieldrin
<0.25
<0.04
<0.3
<0.02
2.70
<0.63
<1 .35
114
<0.09
<0.03
0.4
Aroclor 1221
ppo
0.01*
5872
0.1
0.1
0.07
*0.1
<0.1
<0.01
<0.01
<0.01
<0.01
PCB
Aroclor 1248
42.4
< o.oi
3302
<6
1626
1566
4731
2846
5087
<1 .9
335
*Detection limits vary due to sample size, plant matter interference, and
instrument sensitivity.
-------
TABLE 49 (continued)
-PCB
Site DDT Dieldrin Aroclor 1221 Aroclor 1248
PPb
Hopkinsville
5/20/76 9.38 14.9 260 1469
8/25/76 160-p,p'; 0.4-0,p <0.08* < 0.08 5837
Frankfort
£ 5/24/76 6.6 6.6 < 1.0 1382
00 8/24/76 <0.2 <1.35 1.0 <13.5
Kendallville
5/27/76 <1.56 5.78 < 1 .0 3672
8/26/76 <1.90 <5.17 < 1.0 449
Columbus
7/13/76 <0.4 <0.04 < 0.4 <15
11/29/76 0.9 <0.18 < 0.1 <27
*Detection limits vary due to sample size, plant matter interference, and
instrument sensitivity.
-------
TABLE 50. CHLORINATED HYDROCARBON CONCENTRATIONS
IN SURFACE SOIL COMPOSITES
ro
10
Site/Plot
Macon
Treated
Control
Las Virgenes
Treated
Control
Wilmington
Treated
Control
Springfield
Treated
Control
Chippewa Falls
Treated
Control
DDT
0.11
0.05
0.03
0.15
<0.01
<0.01
<0.01
0.12
<0.001
<0.001
Dieldri n
0.56
0.04
0.20
<0.03
0.84
0.01
<0.02
<0.02
<0.001
<0.001
Aroclo
1.
<0.
0.
0.
<0.
<0.
1
0.
10.
< 0.
F
r 1221
ppb ....
6
02*
09
01
5
5
02
5
06
»CB
Aroclor 1248
0.2
<0.04
<0.01
0.28
99
<0. 4
120
<]
0.001
<0.06
*Detection limits vary due to sample size, plant matter interference, and
instrument sensitivity.
-------
TABLE 50 (continued)
CO
o
Site/Plot
PCB
DDT
D i e 1 d r i n
Aroclor 1221
Aroe-lor 1248
Hopkinsville
Treated
Control
Frankfort
Treated
Control
Kendallville
Treated
Control
Columbus
Treated
Control
<0
<0
0
<0
0
<0
0
<0
.007 *
.007
.5
.007
.29
.01
.13
.01
0
0
0
<0
0
<0
<0
<0
.47
.007
.004
.007
.08
.02
.01
.01
<0
<0
<0
<0
300
<-|
<0
<0
.75
.75
.75
.75
.5
.5
<0 . 5
<0 .5
<0 . 5
<0 . 5
< 1
<-1
216
<0 . 4
*Detection limits vary due to sample size,
instrument sensitivity.
plant matter interference, and
-------
TABLE 51. CHLORINATED HYDROCARBON CONCENTRATIONS
IN COMPOSITE PLANT SAMPLES
Site/Plot
Macon
Treated
Control
Las Virgenes
Treated
Control
Wilmington
Treated
Control
Springfield
Treated
Control
Chippewa Falls
Treated
Control
Chippewa Falls
Soy Beans
Treated
Control
DDT
<0.07*
<0.08
0.28
<0.01
<0.02
<0.02
-------
TABLE 51
(continued)
CO
ro
Site/Plot
Hopkinsville
Treated
Control
Frankfort
Treated
1 Control
I
Frankfort
Wheat Grains
Treated
Control
Kendallville
Treated
Control
Columbus
Treated
Control
Columbus
Corn Grains
Treated
Control
DDT
<0.01*
<0.01
<0.125
<0.25
<0.01
<0.01
<0.02
<0.02
<0.02
<0.02
<0.001
<0.004
D i e 1 d r i n
20
<0.02
3t
3t
<0.02
<0.02
<0.04
<0.04
<0.01
<0.01
<0.001
<0.002
P
Aroclor 1221
<1 .17
<0.83
<0.17
<0.17
<0.01
<0.01
<1
<1
<0.25
<0.75
<0.01
<0.01
'CB
Aroclor 1248
<0.11
<0.22
<0.11
<0.11
<0.01
<0.01
<0.11
<0.11
<0.75
<0.5
<0.01
<0.01
*Detection limits vary due to sample size, plant matter interference, and instrument sensitivity.
tPI ant matter interference.
-------
Dieldrin--
Six of the sl.udges (Las Virgenes, California; Springfield,
Missouri; Chippewa Falls, Wisconsin; Hopkinsvi1le, Kentucky;
Frankfort, Indiana; and Kendal1vi11e, Indiana) show measurable
amounts of Dieldrin. The highest recorded level was 114 ppb at
Springfield. Of these, the treated surface soils at Las Virgenes,
Hopkinsville, Macon, Wilmington, and Kendallville showed increased
levels of Dieldrin with respect to their individual control plots.
Microbiology
Sludge--
The sludges in general displayed microbiological identities
for each process step (raw sludge to soil) similar to published
data (Kenner, 1972). The failure to detect parasitic helminth
ova in some of the samples analyzed would appear to be an atypical
result. The random sampling, the small number of samples, and
the tendency for the helminth ova to sediment-out during the
anaerobic digester residence time, all contribute to the absence
of helminths in a limited sampling program. Several investiga-
tors have reported helminth densities of 60 to 80 ova/£ of sewage
(Aiba et al., 1965, Liebman, 1965); human contribution is reported
to be TU percent with the remainder of animal origin.
S^almonel 1 a sp. or Shi gel! a sp. were not detected at any point
in the sewage treatment plant process except in the raw sludge at
Springfield, Missouri, suggesting that these pathogens, generally
low in numbers in raw sludge, do not survive the environment out-
side the human envelope, unless conditions are especially favor-
able. Viability tests for the various ova detected were all
inconclusive due to the low density of the eggs for which incuba-
tion and embryonation could be attempted.
Soil--
The only parasite detected in soil samples was from Macon,
Georgia, at the first depth below the surface. The presence of
parasites in only four of the nine sludges is atypical, as
mentioned above. The presence of these organisms in the sludge
gives statistical weight to their probably being present in the
soils given a larger sampling base for detection.
Salmonella sp. or Shigella sp. were found in soil samples
(at Hopkinsville, Kentucky), a fact generally reported for sludge
disposal projects with similar operations and practices for which
microbiological monitoring data are published (Storm, et al . ,
1976, Storm, e_t a]_. , 1977).
The approximate one-log reduction in fecal streptococci
organisms per 20 cm of soil depth increase at Las Virgenes,
California~ and Columbus, Indiana is to be expected, as physical
entrapment of organisms in the upper zones of the soil matrix
133
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occurs. Other biotlc and abiotic factors which favor a decrease
in numbers of organisms with depth are anaerobiosis for non-
facultative species, competition with the resident soil flora,
and enzymatic destruction of cells during further decomposition
of the sludge-soil mixture.
The soil data from Wilmington, Ohio indicate a FC and FS
profile closely resembling those in similar studies, wherein
FC/FS ratios for feces excreted by man and animals differ signifi-
cantly; for man the FC/FS ratio is 4.4:1 while for cattle it is
0.2:1 (Mara, 1974). Additionally, the history of the site shows
a continual monthly application of sludge. The apparent inactiva-
tion of these organisms at 99.99 percent (nominal 30-day inactiva-
tion period) compares to published data for like methods of sludge
disposal (Storm e_t^ aj_. , 1976, Storm e_t al ., 1977). These data
suggest that the FS group of organisms find conditions for sur-
vival in soil more favorable than do the FC group.
Three of the sites (Las Virgenes, California; Springfield,
Missouri; and Hopkinsville, Kentucky) have histories of grazing
animals; the FC/FS data from Las Virgenes and Hopkinsville suggest
that animal activity, and not the sludge, may have contaminated
the soil.
Plants--
Neither parasites nor Salmonella sp. or Shigella sp.
organisms were detected in plant tissue. These results are not
unexpected.
Alfalfa was the crop sampled at both Wilmington, Ohio and
Kendallville, Indiana. Both crops had been planted in previous
years and consequently had been present when sludge was spread.
Their microbiological characters were remarkably similar in fecal
organism count.
Perennial fescue was sampled from the Springfield, Missouri
and Hopkinsville, Kentucky sites. The microbiological data of
each also indicate a close similarity, probably reflecting a
combination of direct contact with sludge, aeolian transport of
dust particles, and the incidental microflora from pasture animals
No special significance can be attributed to either the
total aerobic or FS counts on the soybean leaves, wheat stalks,
or corn leaves from Chippewa Falls, Wisconsin; Frankfort and
Columbus, Indiana, respectively. The FS counts can probably be
attributed to aeolian transport of dust-containing organisms
of animal origin.
134
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CHAPTER IX
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APPENDIX
LABORATORY ANALYTICAL PROCEDURES
PROCEDURES
Moi sture
Moisture was determined by placing the sample in an evapora-
tion dish and drying at 105°C (Standard Methods, 13th Edition,
Section 148A, p. 288).
£H
All pH measurements were
pH meter with glass electrode
reference calomel electrode.
periodically under conditions
close as possible to those of
solutions at pH 4, 7, and 10.
at a soil/CaCl2 ratio of 1/2.
Nitrate Nitrogen
performed using an Orion Model 701
in combination with a saturated
The pH meter was standardized
of temperature and concentration as
the sample, using standard pH buffer
Soils were run using O.OlRi CaCl2
Nitrate nitrogen was determined by the brucine sulfate
procedure (Standard Methods, Section 213C, p. 461).
Ammonia Nitrogen
Ammonia nitrogen was analyzed by distilling procedure
(Standard Methods, Section 216, p. 469).
Volatile Solids
Volatile solids were determined by igniting a prepared filter
disk of non-filtrable residue for 60 minutes at 550°C (Standard
Methods, 2246, p. 46).
Chloride
Chlorides were determined via
(Standard Methods, Section 112B, p,
the mercuric
97).
nitrate procedure
Sulfate
Sulfates were
(Standard Methods,
determined by
Section 156C,
the Turbidimetric Method
, p. 334).
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Sample Preparation
Soil-Total Extraction--
2.5 g finely ground (<_1 mm particle size) air-dried samples
were digested in 1.5 ml concentrated HN03 followed by 4 ml of
2:1 HN03:HC104. Samples were filtered and diluted to 25 ml .
DTPA Extraction--
10 g of soil were extracted with 20 ml (0.005 M DTPA, 0.01 M
CaClo, and 0.1 M Trie.thanolamine solution at pH 7.30), shaken
for two hours, filtered through Whatman No. 42 filter paper, and
Cd, Cu, Ni, and Zn determined by AA.
SIudge--
2.0 g of oven-dried (60°C) sludge solids were digested in
1.5 ml concentrated HMOs, followed by 4 ml of 2:1 HN03:HC104.
Subsequent additions of the nitric-perchloric mixture were made
until the digest became clear.
Plants--
Plant tissues were placed 1n cheesecloth, bundled, and
dipped repeatedly into a cold, dilute solution of Ivory soap
flakes. The bundles were thoroughly rinsed with tap water,
followed by several successive washes of ultra-pure water (18
megohm). The bundles were then dried in a forced-air oven at
60°C. The cheesecloth was removed and discarded. The dried
tissue was finely ground in a Waring blender mill, placed into
clean plastic vials, and stored under refrigeration.
The digestion procedure was essentially the same as that
used for soils (Total), but with a smaller sample size of 2.0 g.
Ni . Cd, Cu, Zn, Pb, Ag, Mg. Co, Mn, Mo, Fe , Ca. Cr
Elements were determined by atomic absorption techniques
utilizing the following equipment:
A. Jarrell-Ash Dialatom Atomic Absorption
Spectrophotometer
B. Perkin-Elmer Model 240 Atomic Absorption
. Spectrophotometer
Individual analyses were performed according to the speci-
fied operating conditions provided in the equipment manufacturer's
analytical methods manual*»t and an EPA manual*. Non-absorbing
line techniques were utilized for Cd analysis to overcome back-
ground interferences.
*
Perkin-Elmer Corp., 1971
fJarrell-Ash Division, 1974.
#U.S. Environmental Protection Agency, 1974.
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As. Se
Both As and Se were determined by chemical reaction to
form the hydrides and subsequent AA analysis following standard
procedures as referenced above.
H£
Mercury was determined by flameless AA (EPA, 1974, p.
118-126).
K. Na
Potassium and sodium were determined by flame photometry
as outlined in Section 147A, pp. 283-284 in Standard Methods
(13th Edition).
B_
Boron was determined by the carmine spectrophotometric
method as shown in Section 107B, p. 72, Standard Methods.
P (Total)
Phosphorus was determined by the Ascorbic Acid Method as
shown in Section 223F, pp. 532-534 of Standard Methods.
Dieldrin. DDT (and analogs). PCB's
Techniques used included extraction with organic solvents
(acetonitrile, hexane), solvent phase partitioning and gas
chromatography with electron capture detector (detection and
confirmation). These tests were followed by dehydrochlorination
and electron capture GC for PCB's.
Organic Carbon
Organic carbon was determined by the Waikley-Black Method
as shown on pp. 1372-1376 in Methods of Soil Analysis, Part 2,
American Society of Agronomy, 1965.
Texture
Texture of soils was determined by the hydrometer method
as shown on pp. 562-564 in Methods of Soil Analysis, Part 1,
American Society of Agronomy, 1965.
Cation Exchange Capacity
Cation exchange capacity was determined by extraction with
sodium acetate, methanol, and ammonium acetate, followed by
determination (sodium electrode) for sodium, as per Methods of
Soil Analysis, Part 2, p. 899.
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'TJacteriology
Each 100 g sample of sludge, soil, and plant was thoroughly
mixed with 1 a of distilled, sterile water (plant samples were
homogenized). The mixture was strained through a U.S. No. 6
sieve into a 1-gal disposable reinforced paper container. Solids
retained on the sieve were discarded. The remainder was poured
through a No. 5 standard sieve using a sterile wooden tongue
depressor to "screed" the material through the sieve. Solids
retained on the sieve were discarded. The remainder was aspirated
with a "Millipore" or similar suction unit through 6-tol4-u
filters using approximately 133 + ml (1/6 of total) of the mixture
for each aspiration. The remainder was then aspirated through
0.45u filters to collect organisms.
The 3-level test for salmonella sp. . fecal coliform and
fecal streptococci was performed on all sludge soil and plant
samples in accordance with Standard Methods for the Examination
of Water and Wastewater (14th Edition) and the Laboratory
Standards for Bacteriological Analysis prepared by the American
Society of Microbiology. Identification was made of Salmonella
sp. isolates. Quantitive analyses by the Most Probable Numbers
(MPN) technique were made for total mesophilic aerobic forms,
salmonella, shigella, fecal streptococci, and fecal coliform,
and reported as number of organisms per gram.
Helminths/Protozoans
Six 15-test tube samples for each sample were prepared using
standard sedimentation and flotation techniques (saturated zinc
sulfate and 10 percent buffered formalin, respectively). Slides
were prepared from each aliquot sample and examined under a
compound microscope. Quantitation was accomplished using the
MacMaster's slide technique. Viability tests for embryonated ova
were made by hamster inoculation and autopsy 30 days after
inoculation (MacMasters's slide technique).
Statistical Methods
The usual calculations for sample mean, sample standard
deviation, and two-tailed student-T testing of significant
difference between two sample means were performed. The proba-
bilities of incorrectly accepting (Type I error) or of incorrectly
reporting (Type II error) the null hypothesis - that the two
sample means (and hence, the samples themselves) came from the
same population - were kept within the reasonable limitations
of the sampling techniques by using a 90 percent degree.of
confidence.
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