CFR, Part 503
Final
Final Report
November 11,1992
U. S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF SCIENCE AND TECHNOLOGY
ENGINEERING AND ANALYSIS DIVISION
WASHINGTON, DC
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Final Report
Statistical Support Documentation
for the 40 CFR, Part 503
Final Standards for the Use or
Disposal of Sewage Sludge
Volume I
November 11, 1992
Submitted to:
U.S. Environmental Protection Agency
Office of Science and Technology
Engineering and Analysis Division
401 M Street, SW.
Washington, DC 20460
Submitted by:
Science Applications International Corporation
Environmental and Health Sciences Group
7600A Leesburg Pike
Falls Church, Virginia 22043
EPA Contract No. 68-CO-0035, Work Assignment 2-35
SAIC Project No. 1-813-03-2815-350
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PREFACE
Statistical methods and estimates that supported the development of the Final Standards for the Use or
Disposal of Sewage Sludge (40 CFR, Part 503) are presented in this document. Estimates include the
number of Publicly Owned Treatment Works (POTWs) in the Nation in 1988 practicing at least secondary
treatment of wastewater and the estimated concentrations of pollutants of concern in the sewage sludge
used or disposed in 1988 by these POTWs. Reported estimates were produced using data from the 1988
National Sewage Sludge Survey.
in
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CONTENTS
Chapter Page
Volume I
Preface iii
1. Introduction 1-1
1.1 Description of the 1988 National Sewage Sludge Survey (NSSS) 1-1
1.2 Design of the National Sewage Sludge Survey (NSSS) 1-2
1.3 National Sewage Sludge Survey Data Bases 1-4
1.4 Document Organization and Text Conventions 1-4
2. Estimation of the Number of POTWs in the Nation Using Each of the
Regulatory Analytical (RA) Use or Disposal Practices in 1988 2-1
2.1 Regulatory Analytical (RA) Use or Disposal Practices 2-1
2.2 Data Conventions 2-4
2.3 Estimation of National Totals and Variances of the Estimates 2-7
2.4 National Estimates by RA Use or Disposal Practice 2-13
2.5 Comments 2-19
3. Estimation of the Number of Publicly Owned Treatment Works (POTWs) in the
Nation in Each of Four Flow Rate Groups 3-1
3.1 Data Conventions 3-1
3.2 Estimation of National Totals and Variances of the Total Estimates 3-2
4. Stratum Weights 4-1
4.1 Survey Design Stratum Weights 4-1
4.2 Adjusted Stratum Weights 4-4
5. National Estimates for the Total Dry Weight of Sewage Sludge
Used or Disposed in 1988 5-1
6. National Estimates for Selected Aspects of Use or Disposal Practices 6-1
6.1 Management Practices Used to Prevent Runoff to Surface Waters 6-1
6.2 Incineration 6-5
6.3 Surface Disposal 6-7
7. National Concentration Estimates for Pollutants of Concern from the National Sewage
Sludge Survey (NSSS) 7-1
7.1 Chemical Analysis Methods and Reporting Procedures 7-1
7.2 Parameter Estimation with Censored Data 7-5
7.3 Data Conventions and Schemes 7-6
7.4 POTW-Based National Pollutant-Concentration Estimates 7-8
7.5 Distributional Estimates of Pollutant Concentration by
Amount of Sewage Sludge 7-66
7.6 Summary Comments Concerning Statistical Methods and Resulting
Estimates of Pollutant Concentration from the NSSS 7-69
References R-l
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CONTENTS (continued)
Chapter Page
Volume II
Preface iii
8. Comparison of Pollutant Concentrations in Sewage Sludge
after Primary and Secondary Treatment of Wastewater 8-1
8.1 Data Conventions and Statistical Methods 8-1
8.2 Results and Conclusions 8-3
9. Data Integrity Assessments and Edits 9-1
9.1 Data Assessment Techniques 9-1
9.2 Imputed Sewage Sludge Dry Weights 9-6
9.3 Data Integrity Assessments and Edits by POTW 9-22
10. Lognormal Estimates from Stratified Random Samples 10-1
10.1 Motivations for the Study 10-1
10.2 Design and Results of Simulations 10-2
References R-l
Appendix
Part Al Data Listings A-2
Part A2 NSSS Data Conventions Data Base A-151
Part A3 Listing of Pollutant-Concentration Data from 16 POTWs
in the 40 City Study A-164
VI
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TABLES
Table Page
2-1 Definitions of Reported Sewage Sludge Use or Disposal Practices
from the 1988 NSSS Survey Questionnaire 2-5
2-2 1986 Needs Disposal Classification vs. Regulatory Analytical (RA)
Use or Disposal Practice Classification 2-8
2-3 Sampling Fractions for the Questionnaire Survey Strata (fy) 2-11
2-4 Estimates of the Number of POTWs in the Nation by Major Use or Disposal Practice . . 2-14
2-5 Estimates of the Number of POTWs in the Nation by Regulated Analytical (RA)
Use or Disposal Practice 2-15
2-6 Estimates of the Number of POTWs in the Nation by End Use 2-16
2-7a Estimates of the Number of POTWs in the Nation Using Multiple
Regulatory Analytical (RA) Use or Disposal Practices 2-18
2-7b Estimates of the Number of POTWs in the Nation Using Each Regulatory
Analytical (RA) Use or Disposal Practice Combination 2-18
3-1 POTWS in the Questionnaire Survey—1986 NEEDS Flow Rate Classification
vs. 1988 Reported Flow Rate Group Frequencies 3-3
3-2 National Estimates of POTWs by Average Daily Flow Group 3-6
4-1 Sampling Fraction Values for the Questionnaire Survey Strata (fy) 4-3
4-2 Sampling Fractions and Stratum Weights for the Analytical Survey 4-4
4-3 Estimated Number of POTWs Classified as Ineligible/Out of Business 4-5
4-4 Stratum Weights Excluding POTWs Classified as Ineligible/Out of Business 4-5
4-5 POTWs in the Analytical Survey Classified as Using Wastewater Stabilization Ponds ... 4-6
4-6 Estimated Number of POTWs Classified as Ineligible/Out of Business and
Using Wastewater Stabilization Ponds 4-7
4-7 Stratum Weights Excluding POTWs Classified as Ineligible/Out of
Business and Using Wastewater Stabilization Ponds 4-7
5-1 National Estimates for Total Dry Weight of Sewage Sludge Used or
Disposed in 1988—By Regulatory Analytical (RA) Use or Disposal Practice 5-7
5-2 National Estimates for Total Dry Weight of Sewage Sludge Used or
Disposed in 1988—By Regulated End Use 5-8
VII
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TABLES (continued)
Table Page
5-3 National Estimates for Total Dry Weight of Sewage Sludge Used or
Disposed in 1988—By Reported Flow Group 5-9
5-4 National Estimates for Total Dry Weight of Sewage Sludge Used or
Disposed in 1988—By Regulatory Analytical (RA) Use or Disposal Practice
and Dichotomized Reported Flow Group 5-10
5-5 National Estimates for Total Dry Weight of Sewage Sludge Used or
Disposed in 1988—By Regulated End Use and Dichotomized Reported Flow Group ... 5-11
7-1 Frequency of Percent Solids in National Sewage Sludge Samples by
Flow Rate Group 7-4
7-2 Strata and National Pollutant Concentration Estimates from the National
Sewage Sludge Survey Assuming a Lognormal Distribution of Concentration-
Pollutants of Concern 7-14
7-3 Strata and National Pollutant Concentration Estimates from the
National Sewage Sludge Survey Assuming a Lognormal Distribution of
Concentration - Individual Pollutants for Composite Pollutants of Concern 7-22
7-4 Strata and National Pollutant Concentration Estimates from the
National Sewage Sludge Survey Assuming a Lognormal Distribution of
Concentration - Percent Solids, Phosphorus, and Total Kjeldahl Nitrogen 7-27
7-5 National Pollutant Concentration Estimates from the National Sewage
Sludge Survey Using Lognormal and Nonparametric Substitution Method
Estimations Procedures - Pollutants of Concern 7-29
7-6 National Pollutant Concentration Estimates from the National Sewage
Sludge Survey Using Lognormal and Nonparametric Substitution Method
Estimations Procedures - Individual Pollutants for Composite
Pollutants of Concern 7-35
7-7 National Pollutant Concentration Estimates from trie National Sewage
Sludge Survey Using Lognormal and Nonparametric Substitution Method
Estimations Procedures - Percent Solids, Phosphorus, and Total
Kjeldahl Nitrogen 7-39
7-8 National Pollutant Concentration Estimates from the National Sewage
Sludge Survey Using Lognormal and Nonparametric Substitution Method
Estimations Procedures - Standard Deviation and Confidence Interval
for the Mean - Pollutants of Concern 7-41
Vlll
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TABLES (continued)
Table Page
7-9 National Pollutant Concentration Estimates from the National Sewage
Sludge Survey Using Lognormal and Nonparametric Substitution Method
Estimations Procedures - Standard Deviation and Confidence Interval
for the Mean - Individual Pollutants for Composite Pollutants of Concern 7-47
7-10 National Pollutant Concentration Estimates from the National Sewage
Sludge Survey Using Lognormal and Nonparametric Substitution Method
Estimations Procedures - Standard Deviation and Confidence Interval
for the Mean - Percent Solids, Phosphorus, and Total Kjeldahl Nitrogen 7-51
7-11 National Pollutant Concentration Percentile Estimates from the
National Sewage Sludge Survey Using Lognormal and Nonparametric
Substitution Method Estimations Procedures - Pollutants of Concern 7-55
7-12 National Pollutant Concentration Percentile Estimates from the National
Sewage Sludge Survey Using Lognormal and Nonparametric Substitution
Method Estimations Procedures - Individual Pollutants for Composite
Pollutants of Concern 7-60
7-13 National Pollutant Concentration Percentile Estimates from the National Sewage
Sludge Survey Using Lognormal and Nonparametric Substitution Method
Estimations Procedures - Percent Solids, Phosphorus, and Total
Kjeldahl Nitrogen 7-64
7-14 National Pollutant Concentration Estimates from the National Sewage
Sludge Survey Weighted by Amount of Sewage Sludge Disposed - Standard
Deviations and Confidence Intervals for the Mean - Pollutants of Concern 7-70
7-15 National Pollutant Concentration Estimates from the National Sewage
Sludge Survey Weighted by Amount of Sewage Sludge Disposed- Standard
Deviations and Confidence Intervals for the Mean - Individual Pollutants
for Composite Pollutants of Concern 7-74
7-16 National Pollutant Concentration Estimates from the National Sewage Sludge
Survey Weighted by Amount of Sewage Sludge Disposed- Standard Deviations
and Confidence Intervals for the Mean - Percent Solids, Phosphorus, and
Total Kjeldahl Nitrogen 7-76
7-17 Estimated Correlation Coefficients Between Pollutant Concentration and
Sewage Sludge Dry Weight Disposed - Pollutants of Concern 7-77
7-18 Estimated Correlation Coefficients Between Pollutant Concentration and
Sewage Sludge Dry Weight Disposed - Individual Pollutants for Composite
Pollutants of Concern 7-83
IX
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TABLES (continued)
Table Page
7-19 Estimated Correlation Coefficients Between Pollutant Concentration and Sewage
Sludge Dry Weight Disposed - Percent Solids, Phosphorus, and Total Kjeldahl
Nitrogen 7-87
7-20 National Sewage Sludge Mass Based Pollutant Concentration Percentile
Estimates - Pollutants of Concern 7-88
7-21 National Sewage Sludge Mass Based Pollutant Concentration Percentile Estimates -
Individual Pollutants for Composite Pollutants of Concern 7-92
7-22 National Sewage Sludge Mass Based Pollutant Concentration Percentile Estimates -
Percent Solids, Phosphorus, and Total Kjeldahl Nitrogen 7-94
8-1 POTWS in the 40 City Study Eligible for Statistical Comparisons Between Primary
and Secondary Sewage Sludge 8-2
8-2 Pollutant Concentrations in Primary and Secondary Sewage Sludge Using
Data from the 40 City Study 8-5
8-3 Pollutant Concentrations in Primary and Secondary Sewage Sludge Using
Data from the 40 City Study - Nondetects Set to Minimum Level 8-12
8-4 Test of Pollutant Concentrations in Primary and Secondary Sewage Sludge Using
Data from the 40 City Study - Wilcoxon Signed Rank Test on Paired Samples 8-18
9-1 Agreement Statistics for Imputed Values Closer to Reported Sewage Sludge
Generated 9-7
9-2 Agreement Statistics for Imputed Values Closer to Calculated Sewage Sludge
Disposed 9-7
9-3 POTW Comparisons for Imputation 9-8
9-4 Imputed Sewage Sludge Mass Assessment 9-20
10-1 Post-Stratification Population and Sample Sizes for POTWS That Use or
Dispose of Sewage Sludge After Secondary or Better Wastewater Treatment 10-2
10-2 National Sewage Sludge Survey: Selected Distributional Parameters 10-4
A-l Observed Maximum Values for Pollutants of Concern from the
National Sewage Sludge Survey A-2
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FIGURES
Figure Page
\ :« " .
2-1 Overview of NSSS 1988 Reported Disposal Practice Categories and their
Rectification into Regulatory Analytical (RA) Use or Disposal Practices 2-6
PERCENT SOLIDS OF NSSS SAMPLES VERSUS POLLUTANT CONCENTRATIONS:
7-1 ALDRIN-Dry Weight 7-96
7-2 ALDRIN-Wet Weight 7-97
7-3 ARSENIC-Dry Weight 7-98
7-4 ARSENIC-Wet Weight 7-99
7-5 BENZENE-Dry Weight 7-100
7-6 BENZENE-Wet Weight . 7-101
7-7 BENZO(A)PYRENE-Dry Weight 7-102
7-8 BENZO(A)PYRENE-Wet Weight 7-103
7-9 BERYLLIUM-Dry Weight 7-104
7-10 BERYLLIUM-Wet Weight 7-105
7-11 BIS(2-ETHYLHEXYL)PHTHALATE-Dry Weight 7-106
7-12 BIS(2-ETHYLHEXYL)PHTHALATE-Wet Weight 7-107
7-13 CADMIUM-Dry Weight 7-108
7-14 CADMIUM-Wet Weight 7-109
7-15 CHLORDANE-Dry Weight 7-110
7-16 CHLORDANE-Wet Weight 7-111
7-17 CHROMIUM-Dry Weight 7-112
7-18 CHROMIUM-Wet Weight 7-113
7-19 COPPER-Dry Weight 7-114
7-20 COPPER-Wet Weight 7-115
7-21 DIELDRIN-Dry Weight 7-116
7-22 DIELDRIN-Wet Weight 7-117
7-23 HEPTACHLOR-Dry Weight 7-118
7-24 HEPTACHLOR-Wet Weight 7-119
7-25 HEXACHLOROBENZENE-Dry Weight 7-120
7-26 HEXACHLOROBENZENE-Wet Weight 7-121
7-27 HEXACHLOROBUTADIENE-Dry Weight 7-122
7-28 HEXACHLOROBUTADIENE-Wet Weight 7-123
XI
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FIGURES (continued)
Figure Page
7-29 LEAD-Dry Weight 7-124
7-30 LEAD-Wet Weight 7-125
7-31 LINDANE (GAMMA-BHQ-Dry Weight 7-126
7-32 LINDANE (GAMMA-BHC)-Wet Weight 7-127
7-33 MERCURY-Dry Weight 7-128
7-34 MERCURY-Wet Weight 7-129
7-35 MOLYBDENUM-Dry Weight 7-130
7-36 MOLYBDENUM-Wet Weight 7-131
7-37 N-NITROSODIMETHYLAMINE-Dry Weight 7-132
7-38 N-NITROSODIMETHYLAMINE-Wet Weight 7-133
7-39 NICKEL-Dry Weight 7-134
7-40 NICKEL-Wet Weight 7-135
7-41 PCB-1016-Dry Weight 7-136
7-42 PCB-1016-Wet Weight 7-137
7-43 PCB-1221-Dry Weight 7-138
7-44 PCB-1221-Wet Weight 7-139
7-45 PCB-1232-Dry Weight 7-140
7-46 PCB-1232-Wet Weight 7-141
7-47 PCB-1242-Dry Weight 7-142
7-48 PCB-1242-Wet Weight 7-143
7-49 PCB-1248-Dry Weight 7-144
7-50 PCB-1248-Wet Weight 7-145
7-51 PCB-1254-Dry Weight 7-146
7-52 PCB-1254-Wet Weight 7-147
7-53 PCB-1260-Dry Weight 7-148
7-54 PCB-1260-Wet Weight 7-149
7-55 SELENIUM-Dry Weight 7-150
7-56 SELENIUM-Wet Weight 7-151
7-57 TOXAPHENE-Dry Weight 7-152
7-58 TOXAPHENE-Wet Weight 7-153
xn
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FIGURES (continued)
Figure Page
7-59 TRICHLOROETHENE-Dry Weight 7-154
7-60 TRICHLOROETHENE-Wet Weight 7-155
7-61 ZINC-Dry Weight 7-156
7-62 ZINC-Wet Weight 7-157
7-63 4,4-DDD-Dry Weight 7-158
7-64 4,4-DDD-Wet Weight 7-159
7-65 4,4-DDE-Dry Weight 7-160
7-66 4,4-DDE-Wet Weight 7-161
7-67 4,4-DDT-Dry Weight 7-162
7-68 4,4-DDT-Wet Weight 7-163
7-69 PHOSPHORUS - Dry Weight 7-164
7-70 PHOSPHORUS - Wet Weight 7-165
7-71 TOTAL KJELDAHL NITROGEN - Dry Weight 7-166
7-72 TOTAL KJELDAHL NITROGEN - Wet Weight 7-167
CUMULATIVE DISTRIBUTION FUNCTIONS:
7-73 ALDRIN 7-168
7-74 ARSENIC 7-169
7-75 BENZENE 7-170
7-76 BENZO(A)PYRENE 7-171
7-77 BERYLLIUM 7-172
7-78 BIS(2-ETHYLHEXYL)PHTHALATE 7-173
7-79 CADMIUM 7-174
7-80 CADMIUM* - Excluding Extreme Outlier Observation from Stratum 3 7-175
7-81 CHLORDANE 7-176
7-82 CHROMIUM , 7-177
7-83 COPPER 7-178
Xlll
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FIGURES (continued)
Figure Page
7-84 DIELDRIN 7-179
7-85 HEPTACHLOR 7-180
7-86 HEXACHLOROBENZENE 7-181
7-87 HEXACHLOROBUTADIENE 7-182
7-88 LEAD 7-183
7-89 LINDANE (GAMMA-BHC) 7-184
7-90 MERCURY 7-185
7-91 MOLYBDENUM 7-186
7-92 N-NITROSODIMETHYLAMINE 7-187
7-93 NICKEL 7-188
7-94 PCB-1016 7-189
7-95 PCB-1221 7-190
7-96 PCB-1232 7-191
7-97 PCB-1242 7-192
7-98 PCB-1248 7-193
7-99 PCB-1254 7-194
7-100 PCB-1260 7-195
7-101 SELENIUM 7-196
7-102 TOXAPHENE 7-197
7-103 TRICHLOROETHENE 7-198
7-104 ZINC 7-199
7-105 4,4-DDD 7-200
7-106 4,4-DDE 7-201
xiv
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FIGURES (continued)
Figure Page
7-107 4,4-DDT 7-202
7-108 PHOSPHORUS 7-203
7-109 TOTAL KJELDAHL NITROGEN 7-204
7-110 PERCENT SOLIDS 7-205
8-1 Aldrin Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-23
8-2 Aldrin Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-23
8-3 Arsenic Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-24
8-4 Arsenic Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-24
8-5 Benzene Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-25
8-6 Benzene Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-25
8-7 Benzidene Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-26
8-8 Benzidene Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-26
8-9 Benzo(a)pyrene Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-27
8-10 Benzo(a)pyrene Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-27
8-11 Beryllium Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-28
8-12 Beryllium Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-28
xv
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FIGURES (continued)
Figure Page
8-13 Bis(2-ethylhexyl)phthalate Concentrations in Primary and Secondary
Sewage Sludge (Nondetects Set to Zero) 8-29
8-14 Bis(2-ethylhexyl)phthalate Concentrations in Primary and Secondary
Sewage Sludge (Nondetects Set to Minimum Level) 8-29
8-15 Cadmium Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-30
8-16 Cadmium Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-30
8-17 Chlordane Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-31
8-18 Chlordane Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-31
8-19 Chromium Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-32
8-20 Chromium Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-32
8-21 Copper Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-33
8-22 Copper Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-33
8-23 Cyanide Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-34
8-24 Cyanide Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-34
8-25 DDD Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-35
8-26 DDD Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-35
8-27 DDE Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-36
xvi
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FIGURES (continued)
Figure Page
8-28 DDE Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-36
8-29 DDT Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-37
8-30 DDT Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-37
8-31 Dieldrin Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-38
8-32 Dieldrin Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-38
8-33 Dimethyl Nitrosamine Concentrations in Primary and Secondary
Sewage Sludge (Nondetects Set to Zero) 8-39
8-34 Dimethyl Nitrosamine Concentrations in Primary and Secondary
Sewage Sludge (Nondetects Set to Minimum Level) 8-39
8-35 Heptachlor Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-40
8-36 Heptachlor Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-40
8-37 Hexachlorobenzene Concentrations in Primary and Secondary
Sewage Sludge (Nondetects Set to Zero) 8-41
8-38 Hexachlorobenzene Concentrations in Primary and Secondary Sewage
Sludge (Nondetects Set to Minimum Level) 8-41
8-39 Hexachlorobutadiene Concentrations in Primary and Secondary
Sewage Sludge (Nondetects Set to Zero) 8-42
8-40 Hexachlorobutadiene Concentrations in Primary and Secondary Sewage
Sludge (Nondetects Set to Minimum Level) 8-42
8-41 Lead Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-43
8-42 Lead Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-43
xvu
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FIGURES (continued)
Figure Page
8-43 Lindane Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-44
8-44 Lindane Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-44
8-45 Mercury Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-45
8-46 Mercury Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-45
8-47 Nickel Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-46
8-48 Nickel Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-46
8-49 PCB-1016 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-47
8-50 PCB-1016 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-47
8-51 PCB-1221 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-48
8-52 PCB-1221 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-48
8-53 PCB-1232 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-49
8-54 PCB-1232 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-49
8-55 PCB-1242 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-50
8-56 PCB-1242 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-50
8-57 PCB-1248 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-51
XVlll
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FIGURES (continued)
Figure Page
8-58 PCB-1248 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-51
8-59 PCB-1254 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-52
8-60 PCB-1254 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-52
8-61 PCB-1260 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) . 8-53
8-62 PCB-1260 Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-53
8-63 Selenium Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) 8-54
8-64 Selenium Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-54
8-65 Toxaphene Concentrations in Primary and Secondary Sewage Sludge >
(Nondetects Set to Zero) 8-55
8-66 Toxaphene Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) 8-55
8-67 Trichloroethylene Concentrations in Primary and Secondary
Sewage Sludge (Nondetects Set to Zero) 8-56
8-68 Trichloroethylene Concentrations in Primary and Secondary
Sewage Sludge (Nondetects Set to Minimum Level) 8-56
8-69 Zinc Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Zero) . . . 8-57
8-70 Zinc Concentrations in Primary and Secondary Sewage Sludge
(Nondetects Set to Minimum Level) . . 8-57
10-1 Ten Simulations for Lognormal Random Variables 10-6
10-2 Probability Plots for Ten Simulations of "Aldrin" . . . . ; 10-7
10-3 Probability Plots for Ten Simulations of "Beryllium" 10-8
xix
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FIGURES (continued)
Figure Page
10-4 Probability Plots for Ten Simulations of "Molybdenum" 10-9
10-5 Probability Plots for Ten Simulations of "PCB-1248" 10-10
10-6 Probability Plots for Ten Simulations of "Zinc" 10-11
xx
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Final Report
November 11, 1992
File: CHAP1.TSD
1. INTRODUCTION
This document provides technical background, statistical methods, and resulting estimates of pollutant
concentrations in sewage sludge from Publicly Owned Treatment Works (POTWs) in the Nation that
practice at least secondary treatment of wastewater. Estimates were produced using data from the
national probability sample of POTWs known as the 1988 National Sewage Sludge Survey (NSSS).
Estimates in this document supported the development of pollutant limitations, regulatory impact analysis
(RIA), and aggregate risk analysis in the Final Standards for the Use or Disposal of Sewage Sludge
(40 CFR, Part 503).
Pursuant to Section 405(d) of the Clean Water Act (CWA) of 1977, as amended by the Water Quality
Act of 1987, the Environmental Protection Agency (EPA) proposed a regulation for the final use and
disposal of sewage sludge. For the purpose of the proposed Standards for the Use and Disposal of
Sewage Sludge (40 CFR, Part 503) (54 Federal Register 5746-5902; February 6, 1989), the EPA used
1979-1980 pollutant-concentration data obtained from the "40 City Study." Although the "40 City Study"
provided a reasonable data source for proposing the Part 503 regulation, the EPA believed that a current
and reliable data base was required to support the final regulation. The EPA conducted the NSSS to
fulfill this requirement.
The NSSS data collection effort began in August 1988 and was completed in September 1989. Samples
of final process sewage sludge were collected just prior to use or disposal from 180 POTWs practicing
at least secondary treatment of wastewater. These samples were analyzed for over 400 pollutants
according to analytical protocols adapted specifically for the sewage sludge matrix. In addition, through
the use of a detailed questionnaire, information on sewage sludge use and disposal and operational
practices was collected from 462 secondary treatment POTWs. The Agency announced the availability
of data and information resulting from the NSSS in a Federal Register notice titled "National Sewage
Sludge Survey: Availability of Information and Data and Anticipated Impacts on 40 CFR, Part 503."
Preliminary statistics estimated from NSSS data concerning the number of POTWs in the Nation using
each of nine sewage sludge use and disposal practices in 1988 were reported on October 31, 1990, in the
"Technical Support Documentation for Part I of the National Sewage Sludge Survey: Notice of
Availability." Also reported in the notice were concentration estimates from the NSSS analytical survey
for the 28 pollutants of concern listed in the proposed Final Standards for the Use or Disposal of Sewage
Sludge (40 CFR, Part 503).
This document provides the technical background that supports the production of the final NSSS estimates
to be reported in the final regulation. To introduce the technical portion of this document, a description
of the NSSS and its design follows.
1.1 DESCRIPTION OF THE 1988 NATIONAL SEWAGE SLUDGE SURVEY (NSSS)
The 1988, the NSSS was conducted to collect sewage-sludge-quality and pollutant-detection data that
describe sewage sludge just prior to use and disposal. Sewage-sludge-quality data were augmented with
1988 information concerning sewage sludge generation and treatment processes, current and alternate
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sludge use and disposal practices, and treatment and disposal cost data. These data, which resulted from
a national probability sample of POTWs practicing secondary or advanced treatment of wastewater,
provided reliable and current data that were used to evaluate risk-based pollutant limitations, conduct
regulatory impact analysis (RIA), and develop the aggregate risk analysis (ARA) for the final regulation.
These data will also be used to identify pollutants to be controlled in the subsequent amendments to
Part 503.
1.2 DESIGN OF THE 1988 NATIONAL SEWAGE SLUDGE SURVEY (NSSS)
POTWs across the Nation practicing at least secondary wastewater treatment were selected as the target
population for the NSSS and a national probability sample. Operationally, secondary treatment was
defined as a primary clarification process followed by biological treatment and secondary clarification.
The sampling frame for the NSSS effort was defined by excluding POTWs with "Present Effluent
Characteristics" codes of "No Discharge," "Raw Discharge," and "Advance Primary" from the EPA
Office of Municipal Pollution Control's 1986 NEEDS survey. These exclusions resulted in a sampling
frame of 11,407 secondary treatment POTWs in the 50 States, Puerto Rico, and the District of Columbia.
The NSSS effort consisted of two components—a questionnaire survey and an analytical survey. Each
component survey had its own probability sample of POTWs selected from the sampling frame of 11,407
secondary treatment POTWs identified by the Agency. The two probability samples are related in that
a POTW included in the probability sample for the analytical survey was also included in the
questionnaire survey.
The sampling plan for the questionnaire survey was designed to allow survey results to be analyzed in
two separate ways—by flow rate group and by sewage sludge use and disposal practice. The sampling
frame was partitioned into 24 strata. These strata, created by joint: stratification across four categories of
wastewater flow rate (referred to as survey design groups) and six use and disposal practices created from
data in the 1986 NEEDS survey, are defined below.
• POTW Average Daily Flow Rate Categories:
1. Flow greater than 100 million gallons per day (MOD)
2. Flow more than 10 MOD but less than or equal to 100 MOD
3. Flow more than 1 MGD but less than or equal to 10 MGD
4. Flow less than or equal to 1 MGD.
• POTW Sewage Sludge Use and Disposal Practice Groups:
1. Land application
2. Distribution and marketing
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3. Incineration
4. Monofill (sewage-sludge-only landfill)
5. Co-disposal landfill and other
6. Ocean disposal.
The sample size for each of the 24 strata was statistically determined, to minimize marginal coefficients
of variation for estimating attributes under the assumption that a particular attribute is distributed
hypergeometrically. A total of 479 POTWs was selected randomly from the sampling frame to comprise
the questionnaire survey sample. Each POTW in the sample was sent a 50-page questionnaire containing
questions about general operation and questions specific to use or disposal practices. The questionnaire
gathered general information concerning service area, POTW operations, general sewage sludge use or
disposal practices, pretreatment activities, wastewater and sewage sludge testing frequencies, and POTW
financial information. POTWs also supplied information specific to their use or disposal practices and
indicated which practice(s) would be likely alternatives. The data base created from returned
questionnaires contains responses from 462 POTWs.
POTWs in the analytical survey were restricted to the contiguous States and the District of Columbia.
All POTWs in the analytical survey were included in the questionnaire survey as well. A total of 208
POTWs from the four flow rate categories was selected for sampling and analysis. EPA contract
personnel collected sewage sludge samples just prior to disposal from each POTW according to sampling
and preservation protocols. Contract laboratories analyzed each sample for 412 pollutants. The list of
tested organics, pesticides, metals, dibenzofurans, dioxins, and PCBs was compiled from the CWA
Section 307(a) priority pollutants, toxic compounds highlighted in the "Domestic Sewage Study," RCRA
Appendix VIII pollutants, and contaminants of suspected concern in municipal sludge. Analytical
methods 1624 and 1625 were adapted from standard methods to allow volatile and semi-volatile organic
pollutants to be quantified from the sewage sludge matrix. Pesticides and PCBs were analyzed by method
1618; dibenzofurans and dioxins were quantified using method 1613; and metals, other inorganics, and
classicals were analyzed by standard EPA methods. All analytical methods were either developed,
chosen, or adapted for the sewage sludge matrix to provide the most reliable and accurate measurement
of the 412 pollutants. Analytical data from 180 POTWs are recorded in the NSSS analytical data base.
Printed or computer copies (9-track tape) of the questionnaire survey data base are available from the
National Technical Information Service (NTIS), 5285 Port Royal Road, Springfield, Virginia, 22161.
When ordering printed copies of the questionnaire data (PB 90-107509; cost $97.95) or the analytical data
(PB 90-107491; cost $139.95), specify the PB number. Computer tapes, written under the OS operating
system in SAS transportable code at 1600 bpi with logical record lengths of 80 and block sizes of 8000,
should be readable by CMS, VSE, AOS/VS, PRIMOS, and VMS. The NTIS order number for the NSSS
data tape is PB 90-501834 and the current price is $220. A data element dictionary containing definitions
and specifications for all NSSS variables is also available (PB 90-198961; cost $23.)
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1.3 NATIONAL SEWAGE SLUDGE SURVEY DATA BASES
The complete set of stored NSSS data is located in four component data bases; these are described below.
• Questionnaire Data Base for the NSSS contains questionnaire responses and followup responses
published through the National Technical Information Service (NTIS) in 1990. These data are used
as a historical reference. The EPA Statistical Analysis Section developed and maintains this data
base.
• Data Conventions Data Base for the NSSS contains regulatory analytical (RA) use or disposal
practice classifications, followup responses, and imputed values for missing or improbable responses
for a select set of questions. These data are used in conjunction with the Questionnaire Data Base
and the Analytical Data Base to describe sewage sludge use or disposal practices in 1988. The EPA
Statistical Analysis Section developed and maintains this data base.
• Regulatory Impact Data Base for the NSSS contains questionnaire responses, followup responses,
definition changes, additional information from the 1988 Needs Survey about POTWs that do not
practice secondary or better wastewater treatment, and updated use or disposal information from
POTWs legally required to change from ocean disposal after 1988. These data are used to support
the aggregate risk analysis and the economic impact analysis required for promulgation of the final
sewage sludge use or disposal regulation. The EPA Economic Analysis Section developed and
maintains this data base.
• Analytical Data Base for the NSSS is the sole source of chemical analytical data used from the
survey. These data are used in conjunction with the Revised Questionnaire Data Base for the NSSS
to describe pollutant concentrations across the country in 1988, in conjunction with the Regulatory
Data Base for the NSSS to estimate the environmental effect of current sewage sludge or disposal
practices, and in conjunction with the Regulatory Impact Data Base for the NSSS to estimate the
cost of compliance with the final sewage sludge use or disposal regulations. The EPA Sample
Control Center developed and maintains this data base.
1.4 DOCUMENT ORGANIZATION AND TEXT CONVENTIONS
This document is divided into two volumes containing ten chapters and one appendix. Each chapter
following this introduction is designed to stand alone. Therefore, it is sometimes necessary to repeat
definitions and other information in more than one chapter. Throughout the report, certain text
conventions are used to differentiate between NSSS survey responses (shown CAPITALIZED) and
regulatory analytical (RA) use or disposal practice categories (shown in CAPITALIZED ITALICS). A
summary of the contents of each section follows.
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Volume I
• Chapter 1. Introduction—describes the National Sewage Sludge Survey, including its history and
purpose, how it was designed, and how it supports the Final Standard for the Use or Disposal of
Sewage Sludge (40 CFR, Part 503). The chapter also describes the four NSSS data bases and
outlines the document's organization and text conventions.
• Chapter 2. Estimation of the Number of Publicly Owned Treatment Works in the Nation
Using Each of the Regulated Analytical (RA) Use or Disposal Practices in 1988—provides
technical background and estimates of the number of POTWs in the Nation practicing at least
secondary treatment of wastewater and using each of the RA use or disposal practices in 1988. The
chapter defines six categories of RA disposal practices—LAND APPLICATION, INCINERATION,
SURFACE DISPOSAL, DISPOSAL PRACTICE NOT COSTED FOR PART 503. UNKNOWN USE
OR DISPOSAL PRACTICE, AND INELIGIBLE OR OUT OF BUSINESS; describes data conventions;
and estimates the national totals and variances of the total estimates.
• Chapter 3. Estimation of the Number of Publicly Owned Treatment Works in the Nation for
Each of Four Flow Rate Groups—provides technical background and estimates of the number of
POTWs in the Nation practicing at least secondary treatment of wastewater and using each of the
RA use or disposal practices in 1988 in each of four flow rate groups. The chapter outlines data
conventions and estimates national totals and variances of the total estimates.
• Chapter 4. Stratum Weights—provides both survey design stratum weights for the questionnaire
and analytical surveys and adjusted stratum weights.
• Chapter 5. National Estimates for the Total Dry Weight of Sewage Sludge Used or Disposed
in 1988—provides national estimates for the total dry weight of sewage sludge used or disposed in
1988 by RA use or disposal practice, by RA end use, and by average daily flow rate group.
• Chapter 6. National Estimates for Selected Aspects of Regulated Analytical (RA) Use or
Disposal Practices—discusses several technical aspects of three RA use or disposal practices—LAND
APPLICATION (preventing runoff to surface waters, maintaining control over the ultimate end use,
and using alternative practices), INCINERATION (types of incinerators, afterburners, and where
incinerator ash is disposed), and SURFACE DISPOSAL (monofills used per POTW, estimated depth
to groundwater, release controls, owner of the monofill, and operator of the monofill).
• Chapter 7. National Concentration Estimates for Pollutants—describes physical analysis methods
and reporting procedures, distributional estimation with censored data, fundamental units of analysis,
distributional estimation of pollutant concentrations by POTW, and distributional estimation of
pollutant concentrations by amount of sewage sludge used or disposed.
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Volume II
Chapter 8. Comparison of Primary and Secondary Wastewater Treatment Sewage Sludges
Using the "40 City Study"—compares primary and secondary wastewater treatment sewage sludges.
• Chapter 9. Data Integrity Assessments and Edits—addresses, data integrity and edits including
use and disposal practices, individual POTW responses for total sewage sludge weight, and
assessment and corrective actions to specific RA use and disposal practice responses.
• Chapter 10. Lognormal Estimates from Stratified Random Samples—presents study motivations,
design, and results of the Monte Carlo simulation to illustrate the distributional properties associated
with weighted mixtures of random variables that are lognormally distributed.
• Appendix. Data Listings—provides three data listings. Part Al lists pollutant-concentration data
from the analytical survey. Part A2 provides a listing of the Data Conventions Data Base containing
RA use or disposal classifications and updated dry weights of sewage sludge used or disposed in
1988 for the POTWs in the NSSS. Finally, Part A3 lists pollutant-concentration data for the subset
of 16 POTWs in the "40 City Study" used for statistical testing reported in Chapter 8.
A list of references is provided in both volumes.
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2. ESTIMATION OF THE NUMBER OF POTWs IN THE NATION USING
EACH OF THE REGULATORY ANALYTICAL (RA) USE OR
DISPOSAL PRACTICES IN 1988
In accordance with the final regulation, the six 1986 NEEDS survey disposal practices and the nine 1988
National Sewage Sludge Survey (NSSS) reported disposal practices {which added three to the original
six) were analyzed and reclassified into six new regulatory analytical (RA) use or disposal practices.
Employing NSSS data, this chapter provides the technical background to produce point and interval
estimates of the number of Publicly Owned Treatment Works (POTWs) in the Nation using each of the
six RA use or disposal practices in 1988. Section 2.1 defines the six RA use or disposal practices and
their subclassifications (see boxed definitions below). Section 2.2 provides data conventions and
definitions of key variables. Section 2.3 cites the statistical formulae defining the point estimator of the
total number of POTWs in the Nation from the NSSS stratified random sample data and the variance of
the total estimate and also presents resulting estimates and confidence intervals for major RA use or
disposal practices. Section 2.4 presents national total estimates for all RA use or disposal practices and
end uses. Finally, Section 2.5 provides comments concerning a specific result.
2.1 REGULATORY ANALYTICAL (RA) USE OR DISPOSAL PRACTICES
Definitions for RA use or disposal practices, end uses, and analytical subclassifications are based on three
specific questions asked in the NSSS. In particular, the six RA use or disposal practices were determined
from question 1-24 of the NSSS questionnaire; the Land Application end uses were determined from
questions II-l and III-l. The six major RA use or disposal practice categories are as follows:
1. LAND APPLICATION
2. INCINERATION
3. SURFACE DISPOSAL
4. DISPOSAL PRA CTICE NOT COSTED UNDER PART 503
5. UNKNOWN USE OR DISPOSAL PRACTICE
6. INELIGIBLE OR OUT OF BUSINESS.
To differentiate the six RA use or disposal practices from the six NEEDS survey disposal practices,
and the nine NSSS reported disposal practices, the RA use or disposal practices always appear in the
text in CAPITALIZED ITALICS.
The boxed information that follows outlines the classifications resulting from the analysis of the NSSS
questions, showing two outline levels and subclassifications. The first outline level describes the six RA
use or disposal practices defined under the Final Standards for the Use or Disposal of Sewage Sludge (40
CFR, Part 503). The second outline level details the sewage sludge end uses. Subclassifications for
analysis purposes are provided on both levels. CAPITALIZED words used to describe the
subclassifications are paraphrases of possible responses from the three NSSS questions referred to above.
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CHAP2. TSD
REGULATORY ANALYTICAL (RA) USE OR DISPOSAL PRACTICES
1. LAND APPLICATION
Includes POTWs classified as practicing LAND APPLICATION and DISTRIBUTION AND
MARKETING.
1.1 Agricultural Land
Includes POTWs classified as practicing land application end uses ANIMAL FEED CROP
LAND (NOT PASTURE), HUMAN FOOD CROP LAND, PASTURE LAND, and
OTHER, as appropriate. Also includes the distribution and marketing end uses
FARMERS and OTHER, as appropriate.
1.2 Forests
Includes POTWs classified as practicing land application end uses SILVICULTURE
LAND and OTHER, as appropriate. Also includes the distribution and marketing end use
OTHER, as appropriate.
1.3 Public Contact Sites
Includes POTWs classified as practicing land application end uses or distribution and
marketing end uses GOLF COURSES,"LANDSCAPE CONTRACTORS, MUNICIPAL
PARKS,"HIGHWAYS, and OTHER, as appropriate.
1.4 Reclaimed Land
Includes POTWs classified as practicing land application end uses LAND
RECLAMATION and OTHER, as appropriate. Also includes the distribution and
marketing end use OTHER, as appropriate.
1.5 Sale or Giveaway in a Bag or Similar Enclosure
This classification includes POTWs reporting DISTRIBUTION AND MARKETING to the
end use GENERAL PUBLIC. All other POTWs are assumed to use some different RA
use or disposal practice.
1.6 Undefined Land Application
Includes POTWs classified as practicing land application that could not be classified as to
end use. Also includes distribution and marketing end use OTHER, as appropriate.
1.7 Compost Brokers/Contractors
Includes POTWs classified as practicing DISTRIBUTION AND MARKETING end use
COMPOST BROKERS/CONTRACTORS.
2. INCINERATION
Includes POTWs classified as practicing INCINERATION.
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REGULATORY ANALYTICAL (RA) USE OR DISPOSAL PRACTICES (con't)
3. SURFACE DISPOSAL
Includes POTWs classified as practicing DEDICATED LAND FOR SEWAGE SLUDGE DISPOSAL,
MONOFILL, and SURFACE DISPOSAL. However, POTWs responding that they practice
SURFACE DISPOSAL will be evaluated in relation to other survey responses on a case-by-case basis.
3.1 Dedicated Land
Includes POTWs classified as practicing DEDICATED LAND FOR SEWAGE SLUDGE
DISPOSAL.
3.2 Monofill
Includes POTWs classified as practicing MONOFILL.
3.3 Other Surface Disposal
POTWs classified as practicing Surface Disposal that are not classified as practicing
Dedicated Land or MONOFILL.
4. DISPOSAL PRACTICE NOT COSTED UNDER PART 503
Includes POTWs classified as practicing CO-DISPOSAL LANDFILL and CO-INCINERATION. The
costs and benefits of using these disposal practices are not considered under Final Standards for the
Use or Disposal of Sewage Sludge (40 CFR, Part 503).
5. UNKNOWN USE OR DISPOSAL PRACTICE
Includes POTWs classified as practicing OCEAN DISPOSAL, OTHER, WASTEWATER
STABILIZATION POND, and NO SLUDGE. These facilities may, after implementation of the Final
Standards for the Use or Disposal of Sewage Sludge (40 CFR, Part 503), use or dispose of sewage
sludge in some fashion covered by the regulation.
S.I Ocean Disposal
Includes POTWs classified as practicing OCEAN DISPOSAL.
5.2 Other
Includes POTWs classified as practicing OTHER that did not use or dispose of sewage
sludge in 1988.
5.3 Unknown Transfer
POTWs whose OTHER practice is described as transfer and who cannot otherwise be
classified.
6. INELIGIBLE OR OUT OF BUSINESS
POTWs found to practice less than secondary wastewater treatment and POTWs found to be out of
business.
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2.2 DATA CONVENTIONS
Prior to defining survey strata for sampling design purposes, the use or disposal practices of 11,407
secondary treatment POTWs were determined from information reported in the 1986 NEEDS survey.
Six disposal practices were identified. These practices, referred to as survey disposal practices, are (1)
Land Application, (2) Distribution and Marketing, (3) Incineration, (4) Monofill, (5) Co-disposal Landfill,
and (6) Ocean Disposal. The cross-classification of these six disposal practices, along with the four levels
of average daily flow rate, were multiplied to partition the sampling frame into 24 mutually exclusive
strata. From these 24 strata, a total of 479 POTWs was randomly selected to comprise the NSSS
questionnaire survey sample. Survey stratum identifications for each POTW in the sample are important
to data analyses because (a) the stratum number indicates the sampling fraction to be assigned to the
POTW's data for statistical estimation procedures, and (b) the disposal practice component of the stratum
number indicates the POTW's disposal practice option reported in the 1986 NEEDS survey.
POTWs in the questionnaire survey reported the practice(s) used to dispose of sewage sludge in 1988 in
question 1-24 of the survey document. This question instructed the participant to record the wet weight
of sewage sludge disposed by each of nine disposal practices. The first six of these nine practices are
the same as the 1986 NEEDS survey disposal practices listed above. The remaining three are (7) Co-
incineration, (8) Surface Disposal, and (9) Other. Answers to these nine questions were known as
reported disposal practices. Sewage sludge disposal options for 1988 were expanded to include the three
additional practices listed in question 1-24 because not all of the POTWs responding to the survey used
one of the six 1986 NEEDS survey-based disposal options. The box below summarizes the disposal
practice questions asked in the two surveys.
NEEDS AND NSSS QUESTIONNAIRE CATEGORIES
Survey Disposal Practices
(1986 NEEDS)
Included six categories.
1. LAND APPLICATION
2. DISTRIBUTION AND
MARKETING
3. INCINERATION
4. MONOFILL
5. CO-DISPOSAL LANDFILL
6. OCEAN DISPOSAL
Reported Disposal Practices
(1988 NSSS)
Included the first six categories and
added three more (numbers 7-9).
7. CO-INCINERATION
8. SURFACE DISPOSAL
9. OTHER
Definitions of the first eight reported disposal practices, just as they appeared in the NSSS questionnaire,
are provided in Table 2-1.
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TABLE 2-1
DEFINITIONS OF REPORTED SEWAGE SLUDGE USE OR DISPOSAL
PRACTICES FROM THE 1988 NSSS SURVEY QUESTIONNAIRE
Land Application - The application of liquid, dewatered, dried, or composted sewage sludge to the land by
surface spraying, surface spreading, or subsurface injection. Sludge may be applied to land intended for a
number of end uses including, but not limited to, cropland, pasture, commercially grown turf, silviculture,
land for reclamation, and dedicated sites. The sludge may be applied by the POTW or by a distributor or
end user under a contract or similar control mechanism with the POTW. Note that in this definition, the
POTW has direct control over the application of sewage sludge.
Distribution and Marketing - The give-away, transfer, or sale of sewage sludge or sewage sludge product
(e.g., composted sludge product) in either bagged or bulk form. The POTW does not apply the sludge and
the end-user applying the sludge is not under the direct control of the POTW. Note that a label or notice
provided with the sewage sludge does not constitute direct control.
Sewape Sludge Incineration - The treatment of sewage sludge exclusively in an enclosed device using
controlled flame combustion. Includes all sewage sludge incinerators on site and also, those facilities
transporting sewage sludge to another facility that operates sewage sludge incinerators.
Monofill - A controlled area of land that contains one or more sewage sludge units. A sewage sludge unit is
defined as a controlled area of land where only sewage sludge is placed. The sludge is covered with a cover
material at the end of each operating day or at more frequent intervals.
Co-Disposal Landfill - An area of land or an excavation that is used for the permanent disposal of solid
waste, residuals, and sewage sludges. These include, but are not limited to, municipal landfills that accept
sewage sludge for disposal in conjunction with other waste materials.
Ocean Disposal - Dumping or controlled release of sewage sludge from a barge or other vessel into marine
water.
Co-Incineration - The combined treatment of sewage sludge and combustible waste materials (e.g., trash and
other municipal solid waste) in an enclosed device using controlled flame combustion.
Surface Disposal - A controlled area of land where only sewage sludge is placed for a period of one year or
longer. Sludge placed in this area is not provided with a daily or final cover. (Surface disposal areas may
become naturally covered with vegetation as a result of seed drift). Surface disposal does not include areas
where sludge has formed or is currently being formed and being deposited as a result of ongoing treatment
(e.g., finishing ponds). Surface disposal can be a natural topographical depression, man-made excavation or
diked area formed primarily of earthen material designed to store (not treat) sewage sludge for a period of
one year or longer. Surface disposal also includes placement of sludge in piles for a period of one year or
more, as a means of disposal.
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For the final data estimates, the nine reported disposal practices were redefined into six regulatory
analytical (RA) categories for analysis. As redefined, they are referred to throughout this report as RA
use or disposal practices (defined in Section 2.1). Figure 2-1 provides an overview of how NSSS
reported disposal practices were reclassified into RA use or disposal practices.
Figure 2-1. Overview of NSSS 1988 Reported Disposal Practice Categories and
Their Rectification Into Regulatory Analytical (RA) Use or Disposal Practices
NSSS 1988 Reported Disposal
::•: Practices (which included 4
NEEDS 1986 categories 1^}
1. LAND APPLICATION
2. DISTRIBUTION AND
MARKETING
3. INCINERATION
4. MONOFILL
5. CO-DISPOSAL LANDFILL
6. OCEAN DISPOSAL
7. CO-INCINERATION
8. SURFACE DISPOSAL
9. OTHER
Analytical Distribution of
NSSS W8»
Reported Disposal Practice
1. LAND APPLICATION
(the majority of those
reporting LA)
2. DISTRIBUTION AND
MARKETING
3. INCINERATION
1 LAND APPLICATION
(a portion of those reporting
LA)
4. MONOFILL
5. CO-DISPOSAL
LANDFILL
7. CO-INCINERATION
6. OCEAN DISPOSAL
9. OTHER
|
8. SURFACE DISPOSAL
g POTWj practicing less
:; thin secondary wutewater
& treionent md POTWs no
$ longer in business
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J;
&
n
l-i
_i i
1
use was "dedicated
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P sludge disposal" fl P]
1
1
s
,/
S
S
/
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/
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Reclassified RA Use or
Disposal Practice
/. LAND APPLICATION
? wiRFACF nwpnvAi
4. DISPOSAL PRACTICES
NOTCOSTED UNDER
PART 503
5 UNKNOWN USE OR
DISPOSAL PRACTICE
Evaluated on a case-by-case
basis in relation to POTWs
other survey responses
6. INELIGIBLE OR
OUT OF BUSINESS
Some POTWs that used wastewater stabilization ponds as a form of secondary wastewater treatment
indicated in Question 1-24 that their major disposal practice in 1988 was Surface Disposal. Other POTWs
listed Sludge Lagoon under the Other reported disposal practice category of Question 1-24. Upon further
review of the data and schematics from these facilities, the majority were classified as using wastewater
stabilization ponds—these were then categorized as UNKNOWN USE OR DISPOSAL PRACTICE.
The 1988 RA use or disposal practice for each of the 462 respondent POTWs (17 of 479 did not return
completed questionnaires) was determined from Question 1-24. If a POTW used multiple RA use or
disposal practices, the practice used to dispose of the largest percentage of sewage sludge was assigned
as the major RA use or disposal practice. When the use or disposal practice categories were reclassified,
as detailed above, the reported volume of sewage sludge for each use or disposal practice was reclassified
for each POTW. Following the ^classifications of the sewage sludge volumes, the major RA use or
disposal practice was determined for each POTW.
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Of the 17 POTWs that did not return a completed questionnaire, 4 POTWs were determined to be OUT
OF BUSINESS and 2 POTWs were classified as being INELIGIBLE because they did not perform
secondary treatment of wastewater. In addition, two POTWs that responded to the NSSS were classified
as INELIGIBLE because they did not perform secondary treatment of wastewater and another POTW was
determined to be OUT OF BUSINESS because it did not produce sewage sludge in 1988. No responses
were obtained from 11 POTWs despite several followup contacts. The reported disposal practice for the
11 nonrespondent POTWs was assumed to be the same survey disposal practice reported in the 1986
NEEDS survey. That is, for the purpose of estimating the total number of POTWs in the Nation using
each (reclassified) RA use or disposal practice in 1988, it was assumed that survey nonrespondents did
not change their in disposal practice(s) between 1986 and 1988.
The number of POTWs for each of the six 1986 NEEDS survey disposal practices in the NSSS sample
is recorded by major RA use or disposal practices in Table 2-2. This table displays the reclassifications
of the POTWs from the six 1986 NEEDS categories to the six RA use or disposal practices, as defined
in Section 2.1. Note that numbers 2 and 4 through 6 are missing in the major RA use or disposal
categories because Distribution and Marketing (2) was reclassified as LAND APPLICATION (1), Monofill
(4) was reclassified as SURFACE DISPOSAL (7), Co-disposal Landfill (5) was reclassified as DISPOSAL
PRACTICES NOT COSTED UNDER PART 503 (8), and Ocean Disposal (6) was reclassified as
UNKNOWN USE OR DISPOSAL PRACTICE (9) (see boxed summary above).
2.3 ESTIMATION OF NATIONAL TOTALS AND VARIANCES OF THE ESTIMATES
Estimates of the total number of POTWs in the Nation in 1988 using each of the RA use or disposal
practices and the variances of these total estimates were generated based on methods listed in Cochran
(1977, p. 143, equations 5A.67 and 5A.68) for estimating totals over subpopulations. For a given RA
use or disposal practice, first the number of POTWs in the Nation was estimated from NSSS data for each
of the 24 design strata, then strata estimates were summed to produce national estimates. The equations
from which these estimates were generated are defined below. However, notational conventions must
be established first; these conventions follow.
Subscript Notation:
i = Design flow rate group based on average daily flow rate reported in 1986 NEEDS survey
where (i = 1, 2, 3, 4} is defined as
1 = FLOW > 100 million gallons per day (MGD)
2 = 10 < FLOW < 100 MGD
3 = 1 < FLOW < 10 MGD
4 = FLOW <£ 1 MGD.
2-7
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Final Report
November 11, 1992
CHAP2. TSD
TABLE 2-2
1986 NEEDS DISPOSAL CLASSIFICATION VS REGULATORY ANALYTICAL (RA)
USE OR DISPOSAL PRACTICE CLASSIFICATION
POTWs REPORTING SEVERAL RA USE OR DISPOSAL PRACTICES ARE CLASSIFIED
ACCORDING TO THE PRACTICE USED TO DISPOSE OF THE MAJORITY OF SEWAGE SLUDGE
Major RA Use or Disposal Practice
Frequency
Percent
Row Pet
Col Pet
1
2
3
1986 NEEDS
Based Survey
Disposal
Practice
4
5
6
Total
1
— -
63
13.15
5A .31
36.00
AO
8.35
71. A3
22.86
2
0 .A2
2.94
1.14
6
1.25
17. 1A
3 .A3
6A
13.36
3A.59
36.57
H
0
0.00
0 .00
0 .00
175
36.53
3
0
0.00
0.00
0.00
1
0.21
1.79
1.5A
55
11. A8
80.88
8A.62
1
0.21
2.86
1.5A
8
1.67
A. 32
12.31
0
0.00
0.00
0.00
65
13.57
1
j
9
1.88
7.76
15.79
3
0.63
5.36
5.26
1
0.21
1.A7
1.75
22
A. 59
62.86
38.60
22
A. 59
11.89
38.60
H
0
0.00
0.00
0.00
•
57
11.90
8
— ,
25
5.22
21.55
26.32
11
2.30
19. 6A
11.58
9
1.88
13. 2A
9.A7
6
1.25
17. 1A
6.32
AA
9.19
23.78
A6.32
0
0.00
0.00
0.00
95
19.83
9
13
2.71
11.21
19. AO
0
0.00
0.00
0.00
1
0.21
1.A7
1.A9
0
0.00
0.00
0.00
3A
7.10
18.38
50.75
1
19
3.97
100.00
28.36
67
13.99
10
2
0.42
1.72
22.22
1
0.21
1.79
11. 11
0
0.00
0.00
0.00
0
0.00
0.00
0.00
6
1.25
3.24
66.67
I H
0
0.00
0.00
0.00
9
1.88
11
4
0.84
3.45
36.36
0
0.00
0.00
0.00
0
0.00
0.00
0.00
0
0.00
0.00
0.00
7
1.46
3.78
63.64
I
0
0.00
0.00
0.00
11
2.30
Total
116
24.22
'
56
11.69
•
68
14.20
'
35
7.31
-
185
38.62
-
19
3.97
•
479
100.00
Disposal Practices:
1 = Land Application
2 = Distribution and Marketing
3 = Incineration
4 = Monofill
5 = Co-disposal Landfill
6 = Ocean Disposal
7 = Surface Disposal
8 = Not Costed Under Part 503
9 = Unknown
10 = Ineligible/Out of Business
11 = Nonrespondent
2-8
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Final Report
November 11, 1992
CHAP2.TSD
Subscript Notation (continued):
j = Design disposal practice group based on 1986 NEEDS survey responses where {j = 1,
2, 3, 4, 5, 6} is defined as
1 = Land Application
2 = Distribution and Marketing
3 = Incineration
4 = Monofill
5 = Co-disposal Landfill
6 = Ocean Disposal.
ij = Survey design stratum created by crossing the four levels of flow rate group with the six
disposal practices. Thus, ij = 23 implies that the POTW was classified based on 1986
NEEDS survey data as having an average daily flow rate less than or equal to 100 MGD
but more than 10 MGD and incinerating its sewage sludge
{ij = 11, 12, 13,...,16, 21, 22,...,26,...,41,...,44, 45, 46}.
k = Designates the k* POTW in the ij* design stratum
{k = 1, 2, 3,...,nij}.
r = Major RA use or disposal practice determined from the 1988 NSSS where
{r = 1, 2, 3, 4, 5, 6} is defined as
1 = Land Application
2 = Incineration
3 = Surface Disposal
4 = Not Costed Under Part 503
5 = Unknown
6 = Ineligible/Out of Business.
2-9
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Final Repori
November 11, 1992
CHAP2. TSD
Subscript Notation (continued):
Define
yijkr = 1 if the k"1 POTW in the ij"1 design stratum reported the r"1 practice as its major RA use
or disposal practice
= 0 otherwise.
NJJ = the number of POTWs in the if stratum of the sampling frame.
n:j = the number of POTWs in the if stratum of the sample.
fy = the sampling fraction for the if stratum where
Sampling fraction values for the 24 survey strata are listed in Table 2-3.
To estimate the total number of POTWs in 1988 using each of the major RA use or disposal
practices, the number of POTWs using a given RA use or disposal practice was estimated for each
survey stratum. The national estimate was then obtained by summing the strata estimates. That is,
46 nij v
£ E^
j'j-ll Je-l *- ij
Since yijkr equals 1 if the k* POTW in the ij"1 survey stratum reported the r* RA use or disposal
practice in 1988 and is 0 otherwise, then the sum of yijkr over the index k determines the number of
POTWs in the cell where the if1 row intersects the r* column in a cross tabulation of the survey
stratum versus RA use or disposal practice. Denote the number of POTWs in this cell as n^ where
nijr ^
Therefore, the equation for estimating the national total for the r* RA use or disposal practice in 1988
can be written as
flv
?=y N,,^^
r 4-*i *•! n . .
ij-11
2-10
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Final Report
November 11, 1992
CHAP2.TSD
TABLE 2-3
SAMPLING FRACTIONS FOR THE QUESTIONNAIRE SURVEY STRATA (fi%))
Survey Strata Use Or Disposal Practice
Flow Rate
Group (MGD)
1: > 100
2: 10 - 100
3: 1-10
4: 0-1
Land
Application
(1)
2/2
13/61
26/524
75/1646
Distribution
and Marketing
(2)
8/8
10/18
23/41
15/27
Incineration
(3)
7/7
33/74
27/61
1/2
Monofill
(4)
0
9/11
13/17
13/17
Co-Disposal
Landfill
(5)
7/7
31/148
67/1295
80/7421
Ocean
Disposal
(6)
4/4
11/12
3/3
1/1
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Final Report
November 11, 1992
CHAP2.TSD
Subscript Notation (continued):
The variance for the r"1 RA use or disposal practice estimated total is
46
V -E
ij-ii
N2^
.-ft
The value (1 - f^) is the finite population correction factor. Again, since y^ takes on the values of 1 or
0 to designate the use of the r"1 RA use or disposal practice, then the sum of Yijkr2 over the index k is
equal to n^, which is also equal to the sum of Yijkr over the index k. Therefore, the variance estimator
can be expressed as
46
V(Yr] -
i—(n -1)
lij^rlij -1 '
For computational simplicity, define
and
The variance of the total estimate can now be written as
j =:
This final expression of the variance of the estimate of the total was used for estimate computation.
2-12
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Final Report
November 11, 1992
CHAP2.TSD
Subscript Notation (continued):
Ninety-five percent confidence intervals were produced for the estimated total number of POTWs in the
Nation using each of the major RA use or disposal practices in 1988 from the following formula:
Yr ± 1.96
Table 2-4 records resulting point and interval estimates.
2.4 NATIONAL ESTIMATES BY RA USE OR DISPOSAL PRACTICE
In addition to the national estimates by major RA use or disposal practice, estimates have also been
calculated for the number of POTWs in the Nation using each of the RA use or disposal practices. These
estimates are presented for the number of POTWs in specific RA use or disposal practice categories,
including each of the RA use or disposal practices and each of the end uses. The formula used to
calculate the national estimate of the number of POTWs in the r"1 category is:
i> = Y" N nijr.
1 ^ ^ *J n
where,
Nij = the number of POTWs in the ij"1 stratum of the sampling frame
n;j = the number of POTWs in the Vf stratum of the sample
nijr = the number of POTWs in the ij"1 stratum of the sample and in the r"1
use or disposal practice category.
National estimates of the number of POTWs in the Nation by RA use or disposal practice are presented
in Table 2-5. If a POTW uses two or more practices, the POTW is used in the estimate of each of these
practices. The RA use or disposal practices used for these estimates (the r RA use or disposal practice
categories) are defined below:
r = RA use or disposal practice determined from the 1988 NSSS where
{r = 1, 2, 3, 4, 5, 6} are defined as
1 = Land Application
2 = Incineration
3 = Surface Disposal
4 = Not Costed Under Part 503
5 = Unknown
6 = Ineligible/Out of Business.
2-13
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Final Report
November II, 1992
CHAP2. TSD
TABLE 2-4
ESTIMATES OF THE NUMBER OF POTWs IN THE NATION BY MAJOR USE OR DISPOSAL PRACTICE
to
Use or
Disposal Practice
Land Application
Dist. and Marketing
Incineration
Monof ill
Co-disposal Landfill
Ocean Disposal
Surface Disposal
Not Costed Under Part 503
Unknown
Ineligible/Out of Business
1986 NEEDS
Class ificati on
2,233
94
144
45
8,871
20
11,407
Variance Lower 95%
1988 of the CI on
Estimated 1988 Estimate 1988 Estimate
3,929 146,366 3,179.15
314 10,224 115.82
1.128 67,912 617.22
2,317 116,901 1,646.86
3,205 169,159 2.398.87
514 41,331 114.53
11,407
Upper 95%
CI on
1988 Estimate
4,678.85
512.18
1,638.78
2,987.14
4,011. 13
911.47
Note: Major use or disposal practice is defined as the practice that used or disposed of the greatest dry
POTW.
weight of sewage sludge in 1988 per
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Final Report
November 11, 1992
CHAP2.TSD
The national estimate of the number of POTWs using Land Application is divided into two subestimates
in Table 2-5. Estimates are presented for the number of POTWs in the Nation that use the sale or
giveaway of sewage sludge in a bag or similar enclosure as a Land Application end use, and for the
number of POTWs that use any other Land Application end uses. For these estimates, r is defined as
r = 1 if POTW uses the sale or giveaway in a bag or similar enclosure
= 2 if POTW uses any other land application end use.
TABLE 2-5
ESTIMATES OF THE NUMBER OF POTWs IN THE NATION
BY REGULATED ANALYTICAL (RA) USE OR DISPOSAL PRACTICE
RA Use or
Disposal Practice
Land Application
Sale or Giveaway
Others
Incineration
Surface Disposal
Not Costed Under Part 503
Unknown
Ineligible/Out of Business
Frequency
in NSSS
195
30
194
70
63
128
79
9
National
Estimate
3,987
199
3,967
327
1,158
2.595
3,534
513
Estimates of the number of POTWs in the Nation by each end use are presented in Table 2-6. If a
POTW uses two or more end uses, the POTW is used in the estimate of each of these end uses. The
end uses contained in these estimates (the r end use categories) are defined below:
r = RA use or disposal practice end use determined from the 1988 NSSS where
{r = 1, 2, 3, ..., 16} are defined as
1 = LA: Agricultural Land
2 = LA: Compost Brokers/Contractors
3 = LA: Forests
4 = LA: Public Contact Sites
5 = LA: Reclamation Sites
6 = LA: Sale or Giveaway in a Bag or Similar Enclosure
7 = LA: Undefined
8 = Incineration
9 = SD: Dedicated Land
10 = SD: Monofill
11 = SD: Other
12 = Not Costed Under Part 503
13 = UNK: Ocean Disposal
14 = UNK: Transfer
15 = UNK: Other
16 = Ineligible/Out of Business.
2-15
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Final Report
November 11, 1992
CHAP2. TSD
TABLE 2-6
ESTIMATES OF THE NUMBER OF POTWs IN THE NATION BY END USE
RA Use or Frequency National
Disposal Practice in NSSS ; Estimate
Land Application
Agricultural Land
Compost Brockers/Contr actors
Forests
Public Contact Sites
Reclamation Sites
Sale or Giveaway
Undefined
Incineration
Surface Disposal
Dedicated Land
Monofill
Other
Not Costed Under Part 503
Unknown
Ocean Disposal
Transfer
Other
Ineligible/Out of Business
152
19
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Final Report
November 11, 1992
CHAP2.TSD
National estimates of the number of POTWs in the Nation that use multiple RA use or disposal
practices are presented in Tables 2-7a and 2-7b. Table 2-7a presents estimates of the number of RA
use or disposal practices per POTW. Table 2-7b presents estimates of the number of POTWs using
each combination of RA use or disposal practices. For the estimates in Table 2-7a, r is defined as
r = 1 if POTW uses one RA use or disposal practice
= 2 if POTW uses two RA use or disposal practices
= 3 if POTW uses three RA use or disposal practices.
For the estimates in Table 2-7b, r is defined by the combination of RA use or disposal practices used
by each POTW. The possible values for r are
1 = Incineration
2 = Land Application
3 = Not Costed Under Part 503
4 = Ineligible/Out of business
5 = Surface Disposal
6 = Unknown
7 = Incineration and Land Application
8 = Incineration and Not Costed Under Part 503
9 = Incineration and Surface Disposal
10 = Incineration and Unknown
11 = Land Application and Not Costed Under Part 503
12 = Land Application and Surface Disposal
13 = Land Application and Unknown
14 = Not Costed Under Part 503 and Surface Disposal
15 = Not Costed Under Part 503 and Unknown
16 = Surface Disposal and Unknown
17 = Incineration, Land Application, and Not Costed Under Part 503
18 = Incineration, Land Application, and Surface Disposal
19 = Incineration, Land Application, and Unknown
20 = Incineration, Not Costed Under Part 503, and Surface Disposal
21 = Incineration, Not Costed Under Part 503, and Unknown
22 = Incineration, Surface Disposal, and Unknown
23 = Land Application, Not Costed Under Part 503, and Surface Disposal
24 = Land Application, Not Costed Under Part 503, and Unknown
25 = Land Application, Surface Disposal, and Unknown
26 = Not Costed Under Part 503, Surface Disposal, and Unknown.
2-17
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Final Report
November 11, 1992
CHAP2. TSD
TABLE 2-7a
ESTIMATES OF THE NUMBER OF POTWs IN THE NATION
USING MULTIPLE REGULATORY ANALYTICAL (RA) USE OR DISPOSAL PRACTICES
Number of RA
Use or Disposal Practices
Frequency
in KSSS
National
Estimate
1 Practice
Single
2 Practices
3 Practices
Multiple
419
419
55
5
60
10,724
10,724
659
24
683
TABLE 2-7b
ESTIMATES OF THE NUMBER OF POTWs IN THE NATION USING EACH
REGULATORY ANALYTICAL (RA) USE OR DISPOSAL PRACTICE COMBINATION
RA Use of Disposal
Practice Combinations
Frequency
in NSSS
National
Estimate
One Practice:
Incineration
Land Application
Not Costed Under Part 503
Ineligible/Out of Business
Surface Disposal
Unknown
Two Practices:
Incineration, Land Application
Incineration, Not Costed Under Part 503
Incineration, Surface Disposal
Land Application, Not Costed Under Part 503
Surface Disposal
Unknown
Surface Disposal
Land Application,
Land Application,
Not Costed Under Part 503,
Surface Disposal, Unknown
Three Practices:
Land Application, Not Costed Under Part 503,
Land Application, Not Costed Under Part 503,
Surface Disposal
Unknown
54
149
88
9
52
67
5
9
2
25
5
6
1
2
280
3,439
2,276
513
1,011
3,205
9
36
2
257
29
230
2
95
19
5
2-18
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Final Report
November 11, 1992
CHAP2.TSD
2.5 COMMENTS
As shown in Table 2-7b, the majority (87.5%) of POTWs use only one RA use or disposal practice.
The greatest portion of those POTWs reporting one RA use or disposal practice reported LAND
APPLICATION. Of the 12.5% that reported multiple RA use or disposal practices, most involved
LAND APPLICATION and one other RA use or disposal practice. Nearly half of the POTWs who
reported RA use or disposal practices, reported LAND APPLICATION and NOT COSTED UNDER
PART 503.
Nineteen out of twenty POTWs reporting ocean disposal in the 1986 NEEDS survey were sampled
for the NSSS. These POTWs were reclassified as UNKNOWN USE OR DISPOSAL PRACTICE,
according to the RA use or disposal practice definitions. In view of this reclassification, the estimated
total number of POTWs in the Nation using UNKNOWN USE OR DISPOSAL PRACTICES in 1988
appears excessive. The reason the estimate is excessive can be attributed primarily to one POTW.
There are two POTWs that reported using ocean disposal in 1988 that were not identified in the
category of Ocean Disposal from 1986 NEEDS survey information. One POTW that reported using
ocean disposal in 1988 was classified as using incineration from 1986 NEEDS survey information.
As the 1986 NEEDS survey classification determines the sampling fraction assigned to the POTW,
the sampling fraction for this facility is f33 = 27/61. Therefore, this POTW added l/f33 or 2 to the
estimated total number of POTWs using the UNKNOWN USE OR DISPOSAL CATEGORY PRACTICE
(Ocean Disposal) in 1988. However, the other POTW that reported using ocean disposal in 1988 was
classified from the 1986 NEEDS survey as using Co-disposal Landfill. The sampling fraction for the
survey stratum to which this POTW belonged was f45 = 80/7421. This POTW added l/f45 or 93
POTWs to the estimated total of POTWs using UNKNOWN USE OR DISPOSAL PRACTICES (Ocean
Disposal) in 1988. This change in disposal practice was noted while the questionnaire data base was
being developed. Followup contact with the POTW indicated that, indeed, it used ocean disposal in
1988. A census of all POTWs that used ocean disposal in 1988 confirmed that there were 28 POTWs
in the Nation that used this RA use or disposal practice in 1988.
2-19
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Final Report
November 11, 1992
CHAP3.TSD
3. ESTIMATION OF THE NUMBER OF PUBLICLY OWNED TREATMENT WORKS (POTWs)
IN THE NATION IN EACH OF FOUR FLOW RATE GROUPS
This chapter provides point and interval estimates of the number of Publicly Owned Treatment Works
(POTWs) in the Nation practicing at least secondary treatment of wastewater in 1988 in each of four
flow rate groups—and also provides a basis for producing the reported estimates. Section 3.1 provides
data conventions and definitions of key variables. Section 3.2 cites the statistical formulae defining the
point estimator of the total number of POTWs from the stratified National Sewage Sludge Survey (NSSS)
random sample and the variance of the total estimate; the section also presents estimates and confidence
intervals.
3.1 DATA CONVENTIONS
For sampling purposes, each secondary treatment POTW in the NSSS sampling frame of 11,407 POTWs
was categorized into one of four flow rate groups based on information reported in the 1986 NEEDS
survey. These flow rate groups are referred to as survey design groups and are defined as
1 = FLOW > 100 million gallons per day (MGD)
2 = 10 < FLOW < 100 MGD
3 = 1 < FLOW < 10 MGD
4 = FLOW < 1 MGD.
The cross-classification of these four levels of average daily flow rate with the six survey disposal
practices created from data in the 1986 NEEDS survey were multiplied to partition the sampling frame
into 24 mutually exclusive strata. From these 24 strata, a total of 479 POTWs was randomly selected
to comprise the questionnaire survey sample.
The average daily flow rate in 1988 for each of the 462 respondent POTWs in the questionnaire survey
was extracted from Question 9B. These data were then categorized into one of four flow rate groups.
The categories for 1988 reported flow rate groups are the same ones that were used to categorize the
1986 NEEDS survey flow rate groups. As reported in Chapter 2, four of the seventeen POTWs that did
not return a completed questionnaire were determined to be OUT OF BUSINESS. Another two POTWs
were classified as being INELIGIBLE because they did not perform secondary treatment of wastewater.
No responses were obtained from 11 POTWs despite several followup contacts. The reported flow rate
group for these 11 nonrespondents was assumed to be the flow rate group determined from the 1986
NEEDS survey data. That is, for the purpose of estimating the total number of POTWs in each flow
3-1
-------
Final Report
November 11, 1992
CHAPS. TSD
rate group during 1988, it was assumed that the average daily flow rate classification did not change
between 1986 and 1988 for survey nonrespondents.
Table 3-1 compares the number of POTWs in the NEEDS survey 1986-based flow rate group with the
NSSS sample in each 1988-based reported flow rate group. Cells on the diagonal in Table 3-1 indicate
the number of POTWs in the sample that did not change average daily flow rate categories from 1986
to 1988.
3.2 ESTIMATION OF NATIONAL TOTALS AND VARIANCES OF THE TOTAL
ESTIMATES
Estimates of the total number of POTWs in the Nation in each of the four reported flow rate groups and
the variances of these total estimates were generated based on methods listed in Cochran (1977, p. 143,
equations 5A.67 and 5A.68) for estimating totals over subpopulations. For a given reported flow rate
group, the number of POTWs in the Nation was first estimated for each of the 24 strata. Strata estimates
were then summed to produce national estimates. The equations from which these estimates were
generated are defined below. However, notational conventions must be established first; these
conventions follow.
Subscript Notation:
i = Design flow rate group based on average daily flow rate reported in 1986 NEEDS survey
where {i = 1, 2, 3, 4} is defined as
1 = FLOW > 100 million gallons per day (MGD)
2 = 10 < FLOW < 100 MGD
3 = 1 < FLOW < 10 MGD
4 = FLOW < 1 MGD.
j = Design disposal practice group based on 1986 NEEDS survey responses where {j = 1,
2, 3, 4, 5, 6} is defined as
1 = Land Application
2 = Distribution and Marketing
3 = Incineration
4 = Monofill
5 = Co-disposal Landfill
6 = Ocean Disposal.
3-2
-------
TABLE 3-1.
POTWS IN THE QUESTIONNAIRE SURVEY
1986 NEEDS FLOW RATE CLASSIFICATION VS. 1988 REPORTED FLOW RATE GROUP FREQUENCIES
Frequency
Percent
Row Pet
Col Pet
1
O
1986 NEEDS Based
Flow Rate
Q
4
i
1
24
5.01
85.71
96.00
| . |
1
0.21
0.93
4.00
1 ____-!
0
0.00
0.00
0.00
1 1
0
0.00
0.00
0.00
2
2
0.42
7.14
1.87
[_„._ |
97
20.25
90.65
90.65
1 i
7
1.46
4.40
6.54
1
0.21
0.54
0.93
198?
3
2
0.42
7.14
1.17
7
1.46
6.54
4.09
139
29.02
87.42
81.29
23
4.80
12.43
13.45
3 Reported Flow Rate Group
4567
o
0.00
0.00
0.00
1 _..J
0
0.00
0.00
0.00
h. - _
11
2.30
6.92
6.92
148
30.90
80.00
93.08
0
0.00
0.00
0.00
0
0.00
0.00
0.00
0
0.00
0.00
0.00
4
0.84
2.16
100.00
0
0.00
0.00
0.00
0
0.00
0.00
0.00
0
0.00
0.00
0.00
2
0.42
1.08
100,00
0
0.00
0.00
0.00
2
0.42
1.87
18.18
2
0.42
1.26
18.18
7
1.46
3.78
63.64
TOTAL 25 107 171 159 4 2 11
5.22 22.34 35.70 33.19 0.84 0.42 2.30
total
h
28
5.85
-
107
22.34
-
159
33.19
-
185
38.62
-
479
100.00
Average Daily Flow Rate Groups:
1 = Greater than 100 MGD
2 = 10 < FLOW <= 100
3=1 < FLOW <= 10
4 = FLOW <= 1
5 = Out of Business
6 = Ineligible
7 = Nonrespondents
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Final Report
November 11, 1992
CHAPS. TSD
Subscript Notation (continued):
ij = Survey design stratum created by crossing the four levels of flow rate group with the six
disposal practices. Thus, ij = 23 implies that the POTW was classified based on 1986
NEEDS survey data as having an average daily flow rate less than or equal to 100 MOD
but more than 10 MOD and incinerated its sewage sludge
{ij = 11, 12, 13,. ...16, 21, 22,. ..,26,. ..,41,. ..,44, 45, 46}.
k = Designates the k"1 POTW in the ij"1 design stratum
{k = 1,2,3,...,^}.
r = Reported flow rate group determined form the 1988 NSSS where
{r = 1, 2, 3, 4, 5, 6} are defined as
1 = FLOW > 100 million gallons per day (MOD)
2 = 10 < FLOW < 100 MGD
3 = 1 < FLOW < 10 MGD
4 = FLOW < 1 MGD.
Define
yijkr = 1 if the k* POTW in the ij111 design stratum reported the r"1 flow rate group
= 0 otherwise.
Ny = the number of POTWs in the ij111 stratum of the sampling frame.
ny = the number of POTWs in the ijth stratum of the sample.
fy = the sampling fraction for the \'f stratum where
Sampling fraction values for the 24 survey stratum are listed in Chapter 2, Table 2-4.
To estimate the total number of POTWs in 1988 using each flow rate group, the number of POTWs used
in a given flow rate group was first estimated for each survey stratum. The national estimate was then
obtained by summing the strata estimates. That is,
3-4
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Final Report
November 11, 1992
CHAP3.TSD
Subscript Notation (continued):
«6 "ij v
£ £
ij-ll Jc-1 ri
Since yijkr equals 1 if the k* POTW in the ij* survey stratum was classified in the r* flow rate group
based 1988 average daily flow and is valued 0 otherwise, then the sum of yijkr over the index k determines
the number of POTWs in the cell where the if1 row intersects the r* column in a cross tabulation of the
survey stratum versus reported flow rate group. Denote the number of POTWs in this cell as n^ where
nijr < iijj. Therefore, the equation for estimating the national total for the r"1 flow rate group in 1988
becomes
'ijr
The estimated variance for the r"1 flow rate group total is
v(9.z) =£
2V2,
k-l
ijk~
n,-
The value (1 - fy) is the finite population correction factor. Again, since yijkr takes on the values of 1 or
0 to designate 1988 classification in the r"1 flow rate group, then the sum of Yijltr2 over the index k is equal
to n;jr, which is also equal to the sum of Yijkr over the index k. Therefore,
3-5
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Final Report
November 11, 1992
CHAPS. TSD
For computational simplicity, define
and
The variance of the total estimate can now be expressed as
V(Yr) =
Confidence intervals of 95% were produced for the 1988 estimated total number of POTWs in the Nation
in each of the four flow rate groups using the following formula:
YT ± l.S6*V(Yr)".
Resulting point and interval estimates are recorded in Table 3-2.
TABLE 3-2.
NATIONAL ESTIMATES OF POTWs BY AVERAGE DAILY FLOW GROUP
Reported Flow
>
10 <
1 <
Out
100 MGD
FLOW <=
FLOW <•*
FLOW <=
Group
100
10
1
of Business
Ineligible
1986 NEEDS 1988
Classification Estimated
28 26
324 420
1,941 2,456
9,114 8,090
229
186
Change Variance
1988 Estimate of the
-1986 NEEDS Estimate
-2
96
515
-1,024
229
186
8,
47,
82,
70,
16,
2
968
198
511
796
808
.8
.3
.8
.3
.0
.7
Lower 95%
CI on
Estimate
22.
234.
2,030.
7,526.
-292.
-68.
.73
.39
.18
.99
.51
11
Upper 95Z
CI on
Estimate
29
605
2,881
8,653
750
440
.27
.61
.82
.01
.51
.11
11,407
11,407
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Final Report
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4. STRATUM WEIGHTS
A total of 11,407 POTWs practiced secondary or greater wastewater treatment in 1986 according to the
EPA Office of Municipal Pollution Control's 1986 NEEDS survey. Because conducting a census of these
11,407 POTWS was impractical and cost-prohibitive, the 1988 NSSS survey components gathered data
from a sample of the 11,407 eligible POTWs. This chapter defines stratum weights used to estimate the
characteristics of the 11,407 POTWs based on the data gathered from the sample. Section 4.1 presents
survey design stratum weights for each of the component surveys. Section 4.2 presents stratum weights
adjusted for POTWs determined to be ineligible because they did not perform secondary treatment of
wastewater. Categories classified under regulatory analytical (RA) use or disposal practices will appear
in the text as CAPITALIZED ITALICS.
4.1 SURVEY DESIGN STRATUM WEIGHTS
Sampling designs for the 1988 NSSS were statistically structured to separate the analysis of survey results
by flow rate group and sewage sludge use or disposal practice. The levels of flow rate group and sewage
sludge use or disposal practice used to develop the survey sampling plan are defined below.
Survey Design Flow Rate Group and Use or Disposal Definitions:
• POTW Average Daily Flow Rate Categories:
1. Flow greater than 100 million gallons per day (MOD)
2. Flow more than 10 MOD but less than or equal to 100 MGD
3. Flow more than 1 MGD but less than or equal to 10 MGD
4. Flow less than or equal to 1 MGD.
• POTW Sewage Sludge Use and Disposal Practice Groups:
1. Land Application
2. Distribution and Marketing
3. Incineration
4. Monofill (sewage-sludge-only landfill)
5. Co-disposal Landfill and Other
6. Ocean Disposal.
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Final Report
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Survey strata were created by applying these survey design definitions to the 1 1,407 POTWs eligible for
sampling in the 1988 NSSS. Analysis of the number of POTWs in each stratum revealed that POTWs
were mostly likely to be in the lowest flow rate group and were disproportionately distributed across the
six disposal practices. A statistical sampling plan was developed to ensure that a sufficient number of
POTWs from each stratum were in the survey while also minimizing the number of POTWs to be
sampled. To ensure this goal, a statistical, stratified sampling plan was developed for each component
survey.
POTWs for the questionnaire component of the NSSS were sampled from 24 strata. These strata
represent all possible combinations of the four flow rate groups and six survey design use or disposal
practices. A total of 479 of the 11,407 POTWs in the Nation were sampled for the questionnaire
component of the NSSS. National estimates are produced first by summing the value of the variable
being estimated across the data point values from the POTWs in a given survey stratum. Stratum
estimates then are calculated as a function of the survey stratum sampling fraction. This sampling
fraction, denoted as fy to designate the sampling fraction specific to the f1 flow rate stratum and the 'f
survey design use or disposal practice, is a function of the number of POTWs in the sample from that
stratum (n^) and the number of POTWs in the Nation in that stratum (N;j.) Table 4.1 presents the
sampling fraction values (f^) for the questionnaire component of the NSSS.
To illustrate the use of sampling fractions, suppose one wishes to estimate the total number of POTWs
in the Nation with the attribute Y. Let Y take on the value of 1 if the attribute is present and 0 if the
attribute is absent. First, sum the values of the variable Y for each stratum, then divide the sum of the
variable Y by the sampling fraction. This sequence yields the estimated number of POTWs in the Nation
with attribute Y in the stratum. The mathematical presentation of this operation is presented below.
u = E
Obtain the estimated total number of POTWs in the Nation with attribute Y by summing the estimated
total number of POTWs with the attributed across all strata.
To estimate the national average for a quantitative variable (Y), obtain the same stratum totals as
illustrated previously. However, then divide the national total by the number of POTWs in the Nation.
The formula for estimating a national average is presented below.
E W^ = E ^*« - E
Jc-1 ij'-l •" ij'-l
The far-right component of this equation indicates that a national average is the weighted sum of the strata
averages. Stratum weights, designated as w0, are defined as the number of POTWs in the stratum (Ns)
divided by the number of POTWs in the Nation. Stratum weights for the questionnaire component of
the NSSS appear at the bottom of Table 4-1.
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File: CHAP4.TSD
TABLE 4-1
SAMPLING FRACTION VALUES FOR THE QUESTIONNAIRE SURVEY STRATA (f£J)
Flow
Group
1=
2= 10
3= 1
4= 0
Rate
(MGD)
> 100
- 100
- 10
- 1
Land
Application
(1)
2/2
13/61
26/524
j 75/1646
Survey Strata Us«
Distribution
and Marketing
(2)
8/8
10/18
23/41
15/27
i Or Disposal Pi
Incineration
(3)
7/7
33/74
27/61
1/2
ractice
Monofill
0
9/11
13/17
13/17
Co-Disposal
Landfill
(5)
7/7
31/148
67/1295
80/7421
Ocean
Disposal
(6)
4/4
11/12
3/3
1/1
Stratum Weights for the Questionnaire Survey
1=
2= 10
3= 1
4= 0
> 100
- 100
- 10
- 1
2/11,407
61/11,407
524/11,407
1646/11,407
8/11,407
18/11,407
41/11,407
27/11,407
7/11,407
74/11,407
61/11,407
2/11,407
0
11/11,407
17/11,407
17/11,407
7/11,407
148/11,407
1295/11,407
7421/11,407
4/11,407
12/11,407
3/11,407
1/11,407
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Final Report
November 11, 1992
File: CHAP4. TSD
A separate, but related stratified sample was drawn for the analytical component of the NSSS. In this
case, the objective was to stratify POTWs with respect to the four flow rate groups. A total of 208
POTWs in the questionnaire component of the NSSS were statistically selected for inclusion in the
analytical component of the NSSS. Because of logistics, POTWs for the analytical survey were restricted
to the 11,346 POTWs located in the contiguous United States. The sampling fractions and stratum
weights for the analytical survey are presented in Table 4-2.
TABLE 4-2
SAMPLING FRACTIONS AND STRATUM WEIGHTS FOR THE ANALYTICAL SURVEY
Stratum Sampling Fraction Stratum Weights
(£1)
FLOW > 100 MGD 20/28 28/11,346
10 < FLOW < 100 MGD 56/324 324/11,346
1 < FLOW < 10 MGD 65/1,927 1,927/11,346
FLOW < 1 MGD 67/9,067 9,067/11,346
4.2 ADJUSTED STRATUM WEIGHTS
Analytical samples were obtained from 180 of the 208 POTWs selected for the analytic survey. Four
POTWs were not sampled because they were classified as either OUT OF BUSINESS or INELIGIBLE
under RA use or disposal practices. The remaining 24 POTWs were not sampled due to logistic
difficulties. Population stratum sizes and the population total were adjusted to exclude POTWs that were
classified as OUT OF BUSINESS, INELIGIBLE, or using wastewater stabilization ponds. In addition to
the four POTWs that were not sampled because they were out of business or ineligible, a fifth POTW
in the analytical survey (Episode 1488) was sampled in 1989 but was excluded from the survey because
the facility was not operational during 1988, the time frame of the survey. Stratum weights were adjusted
after excluding the following five POTWs which were classified as OUT OF BUSINESS or INELIGIBLE:
12-49-455, 25-38-345, 45-25-229, 45-42-387, and 45-42-392.
The number of POTWs that were classified as OUT OF BUSINESS and INELIGIBLE in each population
stratum is determined in Table 4-3.
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TABLE 4-3
ESTIMATED NUMBER OF POTWs CLASSIFIED AS INELIGIBLE/OUT OF BUSINESS
Stratum*
Total
6-SYi^Ni/ni
1 = FLOW > 100 MGD
2 <= 10 < FLOW < 100 MGD
3 •= 1 < FLOW < 10 MGD
4 = FLOW < 1 MGD
1
1
0
3
1*28/20 =
1*324/56 =
0*1927/65 =
3*9067/67 =
1
6
0
406
413
The estimated number of POTWs that were OUT OF BUSINESS or INELIGIBLE in 1988 is 413.
Therefore, the adjusted population total of POTWs in the contiguous United States and the District of
Columbia is 10,933. The stratum weights are adjusted to reflect these exclusions as shown in Table 4-4.
TABLE 4-4.
STRATUM WEIGHTS EXCLUDING POTWs CLASSIFIED AS INELIGIBLE/OUT OF BUSINESS
Stratum*
Adjusted
Total
10,933
Stratum Weight =
1 = FLOW > 100 MGD
2 - 10 < FLOW < 100 MGD
3 = 1 < FLOW < 10 MGD
4 - FLOW < 1 MGD
27
318
1,927
8,661
27/10,933
318/10,933
1,927/10,933
8,661/10,933
= 0.0024
= 0.0291
= 0.1763
= 0.7922
1.0000
In addition to the 5 POTWs that were classified as OUT OF BUSINESS or INELIGIBLE, 18 POTWs from
the analytical survey have been identified zis using wastewater stabilization ponds. POTWs using
wastewater stabilization ponds as a form of secondary treatment are excluded from national estimates of
pollutant concentration because no sewage sludge samples were obtained from this treatment process
during the NSSS analytical survey. Samples were not obtained from the POTWs due to sampling
difficulty and because secondary treatment was not complete. These 18 POTWs that were excluded are
listed in Table 4-5.
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Final Report
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TABLE 4-5
POTWs IN THE ANALYTICAL SURVEY CLASSIFIED AS
USING WASTEWATER STABILIZATION PONDS
Survey ID Episode Survey Stratum
45-02-005
45-11-064
45-13-083
45-13-089
45-14-092
45-15-112
45-16-130
45-17-131
45-19-154
45-23-208
45-24-220
45-25-231
45-26-237
45-28-246
45-29-248
45-30-253
45-45-415
45-50-474
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
The estimated number of POTWs in each population stratum using wastewater stabilization ponds or
classified as INELIGIBLE or OUT OF BUSINESS is determined in Table 4-6.
The estimated number of POTWs classified as OUT OF BUSINESS, INELIGIBLE, or using wastewater
stabilization ponds is 2,849. This reduces the adjusted population total of POTWs in the contiguous
United States and the District of Columbia practicing at least secondary treatment of wastewater to 8,497.
The adjusted stratum weights are in Table 4-7.
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Final Report
November 11, 1992
File: CHAP4.TSD
TABLE 4-6
ESTIMATED NUMBER OF POTWs CLASSIFIED AS INELIGIBLE/OUT OF BUSINESS
AND USING WASTEWATER STABILIZATION PONDS
Stratum^
ZY
ij
rYij*Ni/nl
1 = FLOW > 100 MGD
2 = 10 < FLOW < 100 MGD
3 = 1 < FLOW < 10 MGD
4 = FLOW < 1 MGD
1
1
0
21
1*28/20
1*324/56
0*1927/65
21*9067/67
1
6
0
- 2842
Total
23
2849
TABLE 4-7
STRATUM WEIGHTS EXCLUDING POTWs CLASSIFIED AS INELIGIBLE/OUT OF BUSINESS
AND USING WASTEWATER STABILIZATION PONDS
Adjusted Ni
Total
8,497
Stratum Weight = w±
1 - FLOW > 100 MGD
2 - 10 < FLOW < 100 MGD
3 = 1 < FLOW < 10 MGD
4 = FLOW < 1 MGD
27
318
1,927
6,225
1,
6,
27/8
318/8
927/8
225/8
,632
,632
,632
,497
= 0
= 0
= 0
= 0
.00318
.03742
.22679
.73261
1.00000
The adjusted stratum weights, presented above, were used in the calculation of the pollutant-concentration
estimates presented in this document. Notice that, by applying these adjusted population stratum weights
to the stratum estimates, it is implicitly assumed that the pollutant concentrations from the nonsampled
POTWs not classified as OUT OF BUSINESS, INELIGIBLE, or using wastewater stabilization ponds
would have to be quantified at the level of the estimated stratum statistic.
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5. NATIONAL ESTIMATES FOR THE TOTAL DRY WEIGHT OF
SEWAGE SLUDGE USED OR DISPOSED IN 1988
This chapter presents national estimates of the total dry weight of sewage sludge used or disposed in
1988. These estimates, shown in five tables, were produced using data from the National Sewage Sludge
Survey (NSSS). Estimates of total dry weight of sewage sludge were calculated as weighted averages
of survey strata dry weights. Definitions of subscript notations and variables are followed by comments
specific to the production of estimates in each table, a table summary, and the tables themselves.
References in the text to regulatory analytical (RA) use or disposal practice categories appear as
CAPITALIZED ITALICS.
Subscript Notation:
d = Regulatory analytical (RA) use or disposal practice as classified from responses to the
1988 NSSS. The levels that subscript d can assume are listed in the box below. The
second level of definition is the subcategory or end use definition. Capitalized words
used in the subclassifications are paraphrases of possible responses from the NSSS
questionnaire.
REGULATORY ANALYTICAL (RA) USE OR DISPOSAL PRACTICES
1. LAND APPLICATION
Includes Publicly Owned Treatment Works (POTWs) classified as practicing LAND
APPLICATION and DISTRIBUTION AND MARKETING.
1.1 Agricultural Land (LA: AGRI)
Includes POTWs classified as practicing land application uses ANIMAL FEED CROP
LAND (NOT PASTURE), HUMAN FOOD CROP LAND, PASTURE LAND, and
OTHER, as appropriate. Also includes distribution and marketing end uses FARMERS
and OTHER, as appropriate.
1.2 Forests (LA: FORESTS)
Includes POTWs classified as practicing land application end uses SILVICULTURE
LAND and OTHER, as appropriate. Also includes the distribution and marketing end use
OTHER, as appropriate.
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Final Report
November 11, 1992
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REGULATORY ANALYTICAL (RA) USE OR DISPOSAL PRACTICES (Continued)
1. LAND APPLICA T1ON (Continued)
1.3 Public Contact Sites (LA: PUBLIC)
Includes POTWs classified as practicing land application end uses or distribution and
marketing end uses GOLF COURSES, LANDSCAPE CONTRACTORS, MUNICIPAL
PARKS, HIGHWAYS, and OTHER, as appropriate.
1.4 Reclaimed Land (LA: RECLAIMED)
Includes POTWs classified as practicing land application end uses LAND
RECLAMATION and OTHER, as appropriate. Also includes the distribution and
marketing end use OTHER, as appropriate.
1.5 Sale or Giveaway in a Bag or Similar Enclosure (LA: SALE)
This classification includes POTWs reporting DISTRIBUTION AND MARKETING to the
end use GENERAL PUBLIC. All other POTWs are assumed to use some different RA
use or disposal practice.
1.6 Undefined Land Application (LA: UNDEFINED)
Includes POTWs classified as practicing land application that could not be classified as to
end use. Also includes distribution and marketing end use OTHER, as appropriate.
1.7 Compost Brokers/Contractors (UNK: COMPOST)
Includes POTWs classified as practicing DISTRIBUTION AND MARKETING end use
COMPOST BROKERS/CONTRACTORS.
2. INCINERATION
Includes POTWs classified as practicing INCINERATION.
3. SURFACE DISPOSAL
Includes POTWs classified as practicing DEDICATED LAND FOR SEWAGE SLUDGE
DISPOSAL, MONOFILL, and SURFACE DISPOSAL. However, POTWs responding that they
practice SURFACE DISPOSAL will be evaluated in relation to other survey responses on a case-
by-case basis.
3.1 Dedicated Land (SD: DEDICATED)
Includes POTWs classified as practicing DEDICATED LAND FOR SEWAGE SLUDGE
DISPOSAL.
5-2
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Final Report
November 11, 1992
File: CHAP5.TSD
REGULATORY ANALYTICAL (RA) USE OR DISPOSAL PRACTICES (Continued)
3. SURFACE DISPOSAL (Continued)
3.2 Monofill (SD: MONOFILL)
Includes POTWs classified as practicing MONOFILL.
3.3 Other Surface Disposal (SD: OTHER)
POTWs classified as practicing Surface Disposal that are not classified as Dedicated Land
or MONOFILL.
4. DISPOSAL PRACTICE NOT COSTED UNDER PART 503
Includes POTWs classified as practicing CO-DISPOSAL LANDFILL and CO-INCINERATION.
The costs and benefits of using these disposal practices are not considered under Final Standards
for the Use or Disposal of Sewage Sludge (40 CFR, Part 503).
5. UNKNOWN USE OR DISPOSAL PRACTICE
Includes POTWs classified as practicing OCEAN DISPOSAL, OTHER, WASTEWATER
STABILIZATION POND, and NO SLUDGE. These facilities may, after implementation of the
Final Standards for the Use or Disposal of Sewage Sludge (40 CFR, Part 503), use or dispose of
sewage sludge in some fashion covered by the regulation.
5.1 Ocean Disposal (UNK: OCEAN)
Includes POTWs classified as practicing OCEAN DISPOSAL.
5.2 Other (UNK: OTHER)
Includes POTWs classified as practicing OTHER that did not use or dispose of sewage
sludge in 1988.
5.3 Unknown Transfer (UNK: TRANSFER)
POTWs whose OTHER practice is described as transfer and who cannot otherwise be
classified.
6. INELIGIBLE OR OUT OF BUSINESS
POTWs found to practice less than secondary wastewater treatment and POTWs found to be out of
business.
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November 11, 1992
File: CHAP5.TSD
Subscript Notation: (continued)
f = Average daily flow rate group as determined from responses to the NSSS. The levels of
the subscript f are as follows:
1 = FLOW > 100 million gallons per day (MGD)
2 = 10 < FLOW < 100 MGD
3 = 1 < FLOW < 10 MGD
4 = FLOW < 1 MGD.
ij = The survey design stratum designation. There are 24 levels of the ij subscript. The
design stratum from which a POTW was selected determines the probability that a
POTW was included in the NSSS. The first letter, i, designates which of four design
flow rate groups in the design stratum the POTW was sampled from, while the
second letter, j, indicates to which of six 1986 NEEDS survey use or disposal
practice categories the sample POTW belonged.
k = The k* POTW from the ij* design stratum using the d* RA use or disposal practice
in the f* reported flow rate group.
Variable Definitions:
Ydfijk = Dry weight of sewage sludge disposed using the d* RA use or disposal practice by
the k* POTW in reported flow rate group f. The POTW reporting this dry weight
was selected from the ij111 design stratum.
Ydfij. = Total observed dry weight of sewage sludge from sampled POTWs using the d* RA
use or disposal practice in 1988 reported flow group f from the ij* design stratum.
Dry weights are summed across the k POTWs.
Yd.ij. = Total observed dry weight of sewage sludge from sampled POTWs using the d* RA
use or disposal practice in 1988 in the ij* design stratum. Dry weights are first
summed across the k POTWs in the if1 design stratum that belong to reported flow
rate group f and are classified as using the d* RA use or disposal practice. These dry
weight totals are then summed across reported flow rate groups for POTWs in the
ij* design stratum using the d* RA use or disposal practice.
Y fij = Total observed dry weight of sewage sludge from sampled POTWs in the f1 reported
flow rate group from the ij* design stratum. Dry weights are first summed across the
k POTWs in the ij* design stratum that belong to reported flow rate group f and are
classified as using the d* RA use or disposal practice. These dry weight totals are
then summed across RA use or disposal practices for POTWs in the ij* design
stratum.
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Final Report
November 11, 1992
File: CHAP5.TSD
Subscript Notation: (continued)
N^J = Estimated number of POTWs in the nation using the d* RA use or disposal practice
in reported flow rate group f from the if design stratum.
Nd y = Estimated number of POTWs in the nation using the d* RA use or disposal practice
in 1988 in the if design stratum. Totals are summed across reported flow rate
groups for POTWs in the if design stratum using the d* RA use or disposal
practice.
N.fij = Estimated number of POTWs in the nation in the f1 reported flow rate stratum in
1988 from the if design stratum. Totals are then summed across RA use or disposal
practices for POTWs in the if design stratum.
Table Descriptions and Estimation Methods:
Table 5-1 - Reports national estimates of total dry weight of sewage sludge by RA use or disposal
practice. Multiple RA use or disposal practices were allowed for POTWs. The reported total dry weight
of sewage sludge disposed in 1988 for the d"1 RA use or disposal practice was estimated as
Table 5-2 - Reports national estimates of total dry weight of sewage sludge by regulated end use.
Multiple RA use or disposal practices were allowed for POTWs. The reported total dry weight of sewage
sludge disposed in 1988 for the d"1 RA use or disposal practice was estimated as
Table 5-3 - Reports national estimates of total dry weight of sewage sludge by reported flow rate group.
The total volume of dry weight sewage sludge disposed by a POTW was determined by summing sewage
sludge volumes across the POTW's RA use or disposal practices (i.e., Yfijk). The reported total dry
weight of sewage sludge disposed in 1988 for the f4 reported flow rate group was estimated as
5-5
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Final Report
November 11, 1992
File: CHAPS. TSD
Subscript Notation: (continued)
Tables 5-4 and 5-5 - Report national estimates of total dry weight of sewage sludge by RA use or
disposal practice and dichotomized flow rate group. That is, reported flow rates for the facilities were
distinguished as being greater than one million gallons per day or less than or equal to one million gallons
per day. Multiple RA use or disposal practices were allowed for POTWs. The reported total dry weight
of sewage sludge disposed in 1988 for the d* RA use or disposal practice in the f* flow rate category was
estimated as
24
The index d indicates RA use or disposal practice and end use for Tables 5-4 and 5-5, respectively.
Comments:
National estimates of total dry weight of sewage sludge used or disposed in 1988—obtained by summing
total dry weight estimates across categories—reflect rounding errors. For example, the total volume of
sewage sludge disposed in 1988 obtained by summing across RA use or disposal practices as reported
in Table 5-1 is 5,032,834 U.S. Tons. Summing across regulated end use totals reported in Table 5.2,
the estimated total volume of sewage sludge disposed in 1988 is 5,023,709 U.S. Tons. The RA use or
disposal practice estimate exceeds the total end use estimate by 9,125 U.S. Tons or 0.2%.
Generally, the opportunity of rounding error increases as the number of categories being estimated
increases. Discrepancies in the total dry weight estimates are also a result of the assumption that POTWs
with missing values use or dispose of the average dry weight for their use or disposal/flow group
category. Therefore, as the categories change, the average dry weight for each category, which replaces
the missing values, also changes. This results in differences in the total dry weight estimates. National
estimates of total sewage sludge obtained by summing estimated totals reported in the tables are presented
in the Table Summary on the next page.
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November 11, 1992
File: CHAP5.TSD
TABLE SUMMARY
Table
5-1
5-2
5-3
5-4
5-5
Type of Estimates
By RA Use or
Disposal Practice
By Regulated End Use
By Reported Flow
Group
RA Use or Disposal
Practice and Reported
Flow Group
Regulated End Use
and Reported Flow
Group
National Estimate
(U.S. Tons)
5,032,834
5,023,709
5,053,424
5,036,107
5,028,429
Percentage
Difference
as Compared to
. 5,053,424
U.S. Tons
-0.41%
-0.59%
0
-0.34%
-0.49%
Number of
Estimated
Categories
5
15
4
10
30
TABLE 5-1
NATIONAL ESTIMATES FOR TOTAL DRY WEIGHT OF SEWAGE SLUDGE
USED OR DISPOSED IN 1988
BY REGULATORY ANALYTICAL (RA) USE OR DISPOSAL PRACTICE
RA Use or
Disposal Practice
Estimated
Number of POTWs8
Total Dry Weight
(U.S. Tons)
INCINERATION
LAND APPLICATION
NOT COSTED UNDER PART 503
SURFACE DISPOSAL
UNKNOWN
UNKNOWN - ADJUSTED1
327
3,987
2,595
1,158
3,534
3,447
811,669
1,682,235
1,704,394
519,589
314,947
355,927
A single POTW may employ more than one RA use or disposal practice. Therefore, the sum of the estimated number
of POTWs across RA use or disposal practices is greater than the number of POTWs in the nation.
UNKNOWN - ADJUSTED: Total estimates adjusted to reflect total sludge volumes from a census of 28 POTWs using
Ocean Disposal.
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TABLE 5-2
NATIONAL ESTIMATES FOR TOTAL DRY WEIGHT OF SEWAGE SLUDGE
USED OR DISPOSED IN 1988
BY REGULATED END USE
RA Use or Estimated Total Dry Weight
Disposal Practice Number of POTWs8 (U.S. Tons)
INCINERATION 327 811,669
LA: AGRICULTURAL 3,246 1,098,970
LA: COMPOST 145 141,041
LA: FORESTS 30 29,409
LA: PUBLIC 253 155,891
LA: RECLAIMED 68 61,788
LA: SALE 199 66,707
LA: UNDEFINED 488 119,303
NOT REGULATED 2,595 1,704,394
SD: DEDICATED 383 242,892
SD: MONOFILL 320 147,705
SD: OTHER 456 128,993
UNK: OCEAN1 115 314,947
UNK: OTHER 3,397 0
UNK: TRANSFER 22 0
* LA = Land Application
SD = Surface Disposal
UNK = Unknown
aA single POTW may employ more than one end use. Therefore, the sum of the estimated number of POTWs across
end uses is greater than the number of POTWs in the nation.
A census of POTWs using ocean disposal in 1988 revealed that a total of 355,927 U.S. Tons of sewage sludge was
disposed by 28 POTWs.
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TABLE 5-3
NATIONAL ESTIMATES FOR TOTAL DRY WEIGHT OF SEWAGE SLUDGE
USED OR DISPOSED IN 1988
BY REPORTED FLOW GROUP
REPORTED
FLOW GROUP
NUMBER OF POTWs3
Estimated Adjusted13
TOTAL DRY WEIGHT (U.S. Tons')
Estimated Adjusted15
FLOW
10 < FLOW
1 < FLOW
FLOW
100 MGD --> 26
100 MGD 414
10 MGD 2,456
1 MGD 7,997
30
416
2,455
7,905
1,258,861
2,096,094
1,314,161
384,308
1,303,111
2,092,862
1,314,135
384,625
'Excluding POTWs classified as Ineligible or Out of Business.
'Estimates adjusted to reflect data from a census of 28 POTWs using ocean disposal.
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TABLE 5-4
NATIONAL ESTIMATES FOR TOTAL DRY WEIGHT OF SEWAGE SLUDGE
USED OR DISPOSED IN 1988
BY REGULATORY ANALYTICAL (RA) USE OR DISPOSAL PRACTICE
AND DICHOTOMIZED REPORTED FLOW GROUP
RA Use or
Disposal Practice
Reported
Flow Group
Estimated Total Dry Weight
Number of POTWs3 (U.S. Tons)
INCINERATION
FLOW > 1 MGD
FLOW < 1 MGD
234
93
809,777
1,892
LAND APPLICATION
FLOW > 1 MGD
FLOW < 1 MGD
1,274
2,713
1,486,452
196,420
NOT COSTED UNDER
PART 503
FLOW > 1 MGD
FLOW < 1 MGD
1,026
1,569
1,605,714
101,316
SURFACE DISPOSAL
FLOW > 1 MGD
FLOW < 1 MGD
391
766
429,676
89,913
UNKNOWN
FLOW > 1 MGD
FLOW < 1 MGD
262
3,272
314,896
51
UNKNOWN-ADJUSTED
FLOW > 1 MGD
FLOW < 1 MGD
266
3,180
355,887
40
A single POTW may employ more than one RA use or disposal practice. Therefore, the sum of the estimated number
of POTWs across RA use or disposal practices is greater than the number of POTWs in the nation.
Adjusted to reflect a census of 28 POTWs using ocean disposal.
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TABLE 5-5
NATIONAL ESTIMATES FOR TOTAL DRY WEIGHT OF SEWAGE SLUDGE
USED OR DISPOSED IN 1988
BY REGULATED END USE
AND DICHOTOMIZED REPORTED FLOW GROUP
END USE*
INCINERATION
LA: AGRICULTURAL
LA: COMPOST
LA: FORESTS
LA: PUBLIC
LA: RECLAIMED
LA: SALE
LA: UNDEFINED
NOT COSTED UNDER
PART 503
REPORTED ESTIMATED
FLOW GROUP NUMBER OF POTWsa
FLOW > 1 MGD
FLOW < 1 MGD
FLOW > 1 MGD '
FLOW < 1 MGD
FLOW > 1 MGD
FLOW < 1 MGD
FLOW > 1 MGD
FLOW < 1 MGD
FLOW > 1 MGD
FLOW < 1 MGD
FLOW > 1 MGD
FLOW < 1 MGD
FLOW > 1 MGD
FLOW < 1 MGD
FLOW > 1 MGD
FLOW < 1 MGD
FLOW > 1 MGD
FLOW < 1 MGD
234
93
993
2,253
51
95
8
22
200
53
22
46
99
100
194
293
1,026
1,569
TOTAL DRY WEIGHT
(U.S. Tons)
809,777
1,892
954,271
144,699
108,799
32,242
28,356
1,053
150,845
5,046
61,428
361
66,609
98
108,533
12,855
1,605,714
101,316
* LA = Land Application
SD = Surface Disposal
UNK = Unknown
aA single POTW may employ more than one end use. Therefore, the sum of the estimated number of POTWs across
end uses does not represent the total number of POTWs.
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TABLE 5-5 (con't)
NATIONAL ESTIMATES FOR TOTAL DRY WEIGHT OF SEWAGE SLUDGE
USED OR DISPOSED IN 1988
BY REGULATED END USE
AND DICHOTOMIZED REPORTED FLOW GROUP
END USE*
SD: DEDICATED
SD: MONOFILL
SD: OTHER
UNK: OCEAN1
UNK: OTHER
UNK: TRANSFER
REPORTED ESTIMATED
FLOW GROUP NUMBER OF POTWs3
FLOW >
FLOW <
FLOW >
FLOW <
FLOW >
FLOW <
FLOW >
FLOW <
FLOW >
FLOW <
FLOW >
FLOW <
1
1
1
1
1
1
1
1
1
1
1
1
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
MGD
207
176
124
196
61
394
21
94
240
3,157
0
22
TOTAL DRY WEIGHT
(U.S. Tons)
205,541
37,350
125,045
22,659
99,090
29,903
314,896
51
0
0
0
* LA = Land Application
SD = Surface Disposal
UNK = Unknown
aA single POTW may employ more than one end use. Therefore, the sum of the estimated number of POTWs across
end uses is greater than the number of POTWs in the nation.
A census of POTWs using ocean disposal in 1988 revealed that a total of 355,927 U.S. Tons of sewage sludge was
disposed by 28 POTWs. Dichotomized by reported flow group, the totals from the census are:
REPORTED
FLOW GROUP
FLOW > 1 MGD
FLOW s 1 MGD
NUMBER of POTWs
26
2
TOTAL DRY WEIGHT
355,887
40
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Final Report
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File: CHAP6.TSD
6. NATIONAL ESTIMATES FOR SELECTED ASPECTS OF USE
OR DISPOSAL PRACTICES
Chapter 6 discusses special issues concerning three separate sections of the National Sewage Sludge
Survey (NSSS): Section n—Land Application, Section IV—Incineration, and Section V—Monofill. In
these three areas of the NSSS, the Publicly Owned Treatment Works (POTWs) were instructed to
complete multiple copies of Part B for situations described in the Part B instructions. In Section II, a Part
B was to be completed for each Land Application practice employed at the POTW, in Section IV, for
each Incinerator, and in Section V, for each Monofill. Multiple responses were also allowed in some of
the questions in these sections. This chapter describes how national estimates were achieved accounting
for these special circumstances. The national estimates provided herein are lower bounds. This is
because estimates were generated using data only from POTWs that responded to the specific questions.
No imputation was conducted for nonrespondents. Section 6.1 describes management practices used to
prevent runoff to surface waters, Section 6.2 discusses incineration, and Section 6.3 covers surface
disposal. References in the text to regulatory analytical (RA) use or disposal practice classifications
appear as CAPITALIZED ITALICS.
6.1 MANAGEMENT PRACTICES USED TO PREVENT RUNOFF TO SURFACE WATERS
There are 195 POTWs in the NSSS that have been classified under RA use or disposal practice criteria
as using LAND APPLICATION to dispose of sewage sludge in 1988. The estimated total number of
POTWs in the Nation classified as using LAND APPLICATION is 3,987. Of the 195 POTWs in the
NSSS, 161 POTWs responded to the followup question in the Land Application section. Therefore,
national estimates for select aspects of the LAND APPLICATION category are based on those responses
only. No assumptions were made about POTWs that did not respond to the survey.
The questions of concern from the Land Application section (Section II) are Part B, Questions 11-23, II-
28, and 11-31. The following estimates, taken from responses to Question 11-28 were computed for each
POTW. That is, for each possible response, the POTW was considered to have responded "yes" if the
POTW had responded affirmatively to that option for any of its end uses (i.e., any copy of Part B). Any
POTW that did not answer a question was assumed not to have used any of the given options. The copies
of Section II, Part B, relating to the category Dedicated Land, have been excluded from this analysis
because Dedicated Land has been reclassified as SURFACE DISPOSAL.
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11-28. What type of management practices were used to prevent runoff to surface
waters?
a. None
b. Buffer zone
c. Conservation tillage
d. Maximum slope requirement
e. Sediment basin
f. Terracing/berming
g. Other
The following national estimates represent the number of L.4JVD APPLICATION POTWs in the Nation
that use each management practice in at least one of the end uses.
Estimated number of POTWs using None
Estimated number of POTWs using Buffer Zone
Estimated number of POTWs using Conservation Tillage
Estimated number of POTWs using Maximum Slope Requirement
Estimated number of POTWs using Sediment Basin
Estimated number of POTWs using Terracing/Berming
Estimated number of POTWs using Other Management Practices
635
1,843
278
1,632
34
533
169
The following management practices were reported under the category Other:
Site specific
Approved sediment and erosion control plans
Diversion ditch
Use flat areas
Mix with flyash
Injection
Flood plane
High bank containment
Containment of surface runoff
Site checks during storm events
Runoff recirculation
Vegetation
Seasonal restrictions
Hay bales
Sites approved
Land terraced.
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6.1.1 Mechanisms Used to Maintain Control Over the Ultimate End Use
11-23. What type of arrangement or mechanism was used to maintain control over
the ultimate end use of the sewage sludge?
a. Inter-agency agreements
b. Written contract
c. Other written agreement
d. Other
e. None
The following national estimates represent the number of LAND APPLICATION POTWs in the Nation
that use each type of arrangement or mechanism for at least one of the end uses.
Estimated number of POTWs using Inter-Agency Agreements 214
Estimated number of POTWs using Written Contracts 930
Estimated number of POTWs using Other Written Agreements 478
Estimated number of POTWs using Other Mechanisms 384
Estimated number of POTWs using None 278
The other written agreements reported in Question II-23c include:
Land-lease agreement
Instructions prohibit certain end uses
Agreements with land owners
DER permits
State approval
State permit
Instructions/agreement
Land use agreement
Land owner/contractor agreements
State letter
Proof of ins. and letter agreement
Contracts
Permit
PADER permit
Hauling receipt
OEPA sludge management
DER agreement.
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The other mechanisms reported in Question II-23d include:
IEPA permit limit
State permits
MWCC monitoring
No public or private involvement
Verbal agreement
Request from researcher and letter of approval from PADER
Permit from Maine Department Environmental Protection
POTW manages
Permits, supervision by metro
Oral agreement
In-house control
Land application permit
Set price
Verbal contract
County controls
Written site approval
Permit
Land owner.
6.1.2 Alternative Use Or Disposal Practices
11-31. How would you use or dispose of the sewage sludge available as a result of
reduced application rates?
a. Increase acreage within this land application category
b. Apply to other land application categories
c. Pursue other disposal practices (not land application)
d. Other
The following national estimates represent the number of LAND APPLICATION POTWs in the Nation
that would use each alternative use or disposal practice for at least one of the end uses. Question 11-31
was only to be answered if the response to Question 11-29 was "Yes." However, in the NSSS
questionnaire, there were 22 POTWs that responded to Question II-31 even though the response to
Question II-29 was "No," "Not applicable," or was left blank. The responses from these POTWs are
included in the following estimates.
Estimated number of POTWs using increased acreage within the
land application category 810
Estimated number of POTWs applying to other land application
categories 439
Estimated number of POTWs pursuing other disposal practices 314
Estimated number of POTWs using other options 26
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The Other options specified under Question II-31d include:
Unknown
Recycle compost
Transfer to other.
6.2 INCINERATION
There are 68 POTWs in the NSSS questionnaire that have been classified as using INCINERATION. The
estimated total number of POTWs using INCINERATION in the Nation is 307.
For Questions IV-16 and IV-22 in Part B, only one response was permitted per incinerator. However,
there were four POTWs with missing data for these questions. Therefore, they were considered to have
responded "no" to all the options. This accounts for the remaining incinerators which were not included
in the estimates. For Question IV-26, multiple responses were permitted per incinerator. The estimates
for this question represent the number of incinerators using each of the possible responses.
6.2.1 1
'ypes of Incinerators
IV-16a. Indicate below the incinerator type.
1.
2.
3.
4.
5.
Electric furnace
Fluid bed
Multiple hearth
Rotary kiln
Other
The following estimates represent the number of each type of incinerator in the Nation. These estimates
account for 296 of the estimated 431 incinerators in the Nation. The remaining incinerators are a result
of the four POTWs that did not respond to Question IV-16a.
Estimated number of Electric Furnace incinerators 2
Estimated number of Fluid Bed incinerators 49
Estimated number of Multiple Hearth incinerators 242
Estimated number of Rotary Kiln incinerators 0
Estimated number of Other Types of incinerators 3
The other types of incinerators reported in Question IV-16a(5) were flash driers.
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6.2.2 Afterburners
IV-22. Does this incinerator currently have an afterburner installed?
a. No
b. Afterburner with heat exchanger
c. Afterburner without heat exchanger
The following estimates represent the number of incinerators in the Nation with each type of afterburner.
These estimates account for 298 of the estimated 431 incinerators in the Nation. The remaining
incinerators are a result of the 4 POTWs that did not respond to Question IV-22.
Estimated number of incinerators without an afterburner 186
Estimated number of incinerators with an afterburner
with a heat exchanger 27
Estimated number of incinerators with an afterburner
without a heat exchanger 85
6.2.3 Number of Incinerators
IV-1. How many individual incinerators were used to incinerate your sewage
sludge during 1988?
a. On-site incinerators
b. Off-site incinerators
c. Total number of incinerators
From the estimated 307 POTWs in the Nation that use INCINERATION, the estimated total number of
incinerators in the Nation is 431.
6.2.4 Where Incinerator Ash is Disposed
IV-26. Where is this incinerator ash disposed?
a. Co-disposal landfill
b. Metal extraction processing
c. Recycling (e.g., making bricks)
d. Storage lagoon
e. Waste pile
f. Other
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The following estimates represent the number of incinerators in the Nation using each of the ash disposal
options. Each incinerator may use more than one location for ash disposal.
Estimated number of incinerators using Co-Disposal Landfill 152
Estimated number of incinerators using Metal Extraction Processing 0
Estimated number of incinerators using Recycling 6
Estimated number of incinerators using Storage Lagoons 136
Estimated number of incinerators using Waste Piles 12
Estimated number of incinerators using Other Locations 30
The other ash disposal locations specified in Question IV-26f include:
Cement manufacturing
Ash monofill
Ash landfill.
6.3 SURFACE DISPOSAL
In the NSSS questionnaire, 64 POTWs were classified as using SURFACE DISPOSAL to dispose of
sewage sludge in 1988. The SURFACE DISPOSAL classification comprises all POTWs that reported on
the NSSS questionnaire in the categories Surface Disposal, Monofill, or Dedicated Land for Sewage
Sludge Disposal. However, only the POTWs that reported using monofills were required to answer the
followup questions in Section V. Therefore, the following estimates are based only on POTWs reporting
the use of monofills. Of the 64 POTWs classified as using SURFACE DISPOSAL, 33 reported the use
of monofills. The estimated total number of POTWs in the Nation that use monofills is 320.
There are two POTWs that reported the use of monofills but did not respond to the followup questions
in Section V. Because of the survey design strata of these two POTWs, the missing responses represent
112 POTWs in the Nation.
For Questions V-14, V-15, and V-21 in Part B, only one response per question was requested. However,
some POTWs provided multiple responses to these questions. Therefore, the sum of the national
estimates for Questions V-14, V-15, and V-21 (209), plus the estimated national number from the two
POTWs with missing data (112), does not sum to the estimated total number of monofills (320). The
difference is a result of the multiple responses from some POTWs.
For Question V-20 multiple responses were permitted for each monofill.
6.3.1 MonofiHs Used Per POTW
V-l. How many monofills were used in 1988 to dispose of your sewage sludge?
monofills
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From the estimated 320 POTWs in the Nation that use monofills, the estimated total number of monofills
in the Nation is 320. This represents one monofill per POTW. For the 31 POTWs in the NSSS
questionnaire responding to Question V-l, each POTW used only one monofill.
6.3.2 Estimated Depth to Groundwater
V-21. Estimate the depth to groundwater from the bottom of this monofill.
a. No known groundwater source below monofill
b. Monofill is located in groundwater
c. 0 to 0.5 meters
d. 0.6 to 2 meters
e. 2.1 to 8 meters
f. 8.1 to 12 meters
g. Greater than 12 meters
The following estimates represent the number of monofills in the Nation that fall into each of the depth
to groundwater categories. Two POTWs provided more than one response to this question.
Estimated number of monofills with no known groundwater source 3
Estimated number of monofills located in groundwater 1
Estimated number of monofills with depth between 0 and 0.5 meters 3
Estimated number of monofills with depth between 0.6 and 2 meters 53
Estimated number of monofills with depth between 2.1 and 8 meters 8
Estimated number of monofills with depth between 8.1 and 12 meters 2
Estimated number of monofills with depth greater than 12 meters 139
6.3.3 Release Controls
V-20. Describe the discharge controls at this monofill.
a. Cover practices
b. Leachate collection systems
c. Leachate treatment systems
d. Liners, natural
e. Liners, synthetic
f. Methane controls
g. Monitoring wells
h. Runon/runoff controls
i. No controls
j. Other
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The following estimates represent the number of monofills in the Nation that use each discharge control.
Multiple responses per monofill are permitted.
Estimated number of monofills using Cover Practices 199
Estimated number of monofills using Leachate Collection Systems 11
Estimated number of monofills using Leachate Treatment Systems 4
Estimated number of monofills using Natural Liners 124
Estimated number of monofills using Synthetic Liners 5
Estimated number of monofills using Methane Controls 3
Estimated number of monofills using Monitoring Wells 41
Estimated number of monofills using Runon/Runoff Controls 125
Estimated number of monofills using No Controls 4
Estimated number of monofills using Other Controls 19
The only discharge control specified in the category Other Controls in Question V-20J was Lime
Absorption.
6.3.4 Owner of the Monofill
V-14.
Who is the owner
a. YourPOTW
b. Other POTW
c. Municipality
d. Private party
e. State
f. Other
of this monofill?
The following estimates represent the number of monofills in the Nation owned by each of the POTWs
providing possible responses. Two POTWs provided more than one response to this question.
Estimated number of monofills owned by POTW 63
Estimated number of monofills owned by Other POTW 0
Estimated number of monofills owned by Municipality 124
Estimated number of monofills owned by Private Party 21
Estimated number of monofills owned by State 1
Estimated number of monofills owned by Other 0
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6.3.5 C
>perator of
the Monofill
V-14. Who is the operator of this mono fill?
a.
b.
c.
d.
e.
f.
Your POTW
Other POTW
Municipality
Private party
State
Other
The following estimates represent the number of monofills in the Nation which are operated by each of
the POTWs providing possible responses. One POTW provided more than one response to this question.
Estimated number of monofills operated by POTW 72
Estimated number of monofills operated by Other POTW 0
Estimated number of monofills operated by Municipality 96
Estimated number of monofills operated by Private Party 40
Estimated number of monofills operated by State 1
Estimated number of monofills operated by Other 0
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November 11, 1992
CHAP7.TSD
7. NATIONAL CONCENTRATION ESTIMATES FOR POLLUTANTS
OF CONCERN FROM THE NATIONAL SEWAGE SLUDGE SURVEY (NSSS)
This chapter presents estimates of the expected concentrations of pollutants of concern in sewage sludge
used or disposed in 1988 from POTWs in the Nation practicing secondary or greater treatment of
wastewater, excluding wastewater stabilization ponds. National estimates of the standard deviation of
these pollutant concentrations and estimates of the 90th, 95th, 98th, and 99th percentile concentrations are
also included. Concentration estimates are reported for the pollutants of concern because these are the
pollutants that the Agency proposed to regulate in the February 6, 1989 Federal Register, based on
toxicity, persistence, and health and environmental risk. AH elements, compounds, or solids physically
measured will be referred to in this chapter as pollutants. The term pollutant is used here to mean only
that a substance, in certain quantities, could cause harm to the environment; not that it will cause harm
to the environment. In particular, pollutants such as nitrogen and phosphorous are necessary for plant
growth in soil as long as their concentrations in the soil under consideration are within an appropriate
range.
Reported estimates were produced from National Sewage Sludge Survey (NSSS) pollutant-concentration
data using a modified maximum-likelihood estimation technique with the assumption that pollutant
concentrations follow a lognormal distribution. As a point of reference, nonparametric estimates are also
presented. Pollutant concentrations are not assumed to follow any specific distribution for these
nonparametric estimates. Procedures used to quantify and report pollutant concentrations from NSSS
samples and the techniques used to estimate flow rate group and national pollutant concentrations from
the data were discussed in this chapter.
Chemical analysis methods were adapted specifically for the NSSS to facilitate reliable measurement of
pollutants from the sewage sludge matrix (US EPA, 1989B). Section 7.1 discusses these methods and
the procedure for reporting results. Because some pollutants were not detected in concentrations above
the minimum level of detection, NSSS analytical data contains censored observations. Section 7.2
presents an evaluation of the statistical methods available for analyzing data that contain quantitative and
censored observations. Section 7.3 provides data conventions and aggregation schemes. Section 7.4
discusses the statistical procedures and assumptions used to estimate POTW-based pollutant concentrations
from NSSS data. Section 7.4 also presents tabulated POTW-based pollutant-concentration estimates for
the pollutants of concern and graphical presentations of results. Section 7.5 presents the statistical
procedures and assumptions used to estimate mass-based pollutant concentrations and resulting estimates.
Finally, Section 7.6 contains summary comments about the statistical methods used and the resulting
estimates.
7.1 CHEMICAL ANALYSIS METHODS AND REPORTING PROCEDURES
Samples of final process sewage sludge, collected prior to use or disposal from the 180 secondary
treatment POTWs, excluding POTWs using wastewater stabilization ponds, in the stratified NSSS
analytical survey were tested by EPA contract laboratories for 412 pollutants. The list of tested
pollutants, which includes volatile and semi-volatile organics, metals, pesticides, dibenzofurans, dioxins,
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CHAP7.TSD
and PCBs, was formed from the Clean Water Act (CWA) Section 307(a) priority pollutants, toxic
compounds highlighted in the Domestic Sewage Sludge Study, Resource Conservation and Recovery Act
(RCRA) Appendix VIII pollutants, and contaminants of suspected concern in municipal sewage sludge.
Specific analytical protocols were developed for the NSSS to facilitate reliable measurement of pollutant
concentrations from the sewage sludge matrix. Methods 1624 and 1625 for quantifying volatile and semi-
volatile organic pollutants, respectively, were augmented with gel permeation procedures for sample
cleanup. Likewise, ultrasonic techniques in conjunction with extraction procedures increased the
precision and accuracy of pesticides, PCBs, dibenzofurans, and dioxin concentration determinations.
Each pollutant was assigned a minimum level, a form of "detection limit" used by the Agency, in the
analytical method protocol.
If a pollutant was quantified above the minimum level, as adjusted for interferences, the measured
concentration in dry weight units is reported under the variable "AMOUNT" in the NSSS data base.
However, if analytical testing did not yield a concentration above the minimum level, the dry weight
value of the minimum level is recorded for the sample in the variable "DETLIMIT." Minimum level,
as applied to the determination of pollutants by gas chromatography combined with mass spectrometry
(GCMS), is defined by the EPA's Industrial Technology Division as the level at which "the entire
analytical system shall give recognizable mass spectra and acceptable calibration points" (US EPA,
1989B, p. 41). For elemental pollutants, minimum level is defined "the minimum concentration of
substance that can be measured and reported in 99% confidence that the value is above zero" (Ibid., p.
198). In the NSSS, the minimum level is roughly equivalent to the minimum concentration or amount
of pollutant that could be measured.
NSSS pollutant concentrations and minimum levels were reported in dry weight units due to differences
in the solids contents of sewage sludge samples. A pollutant-concentration reported in dry weight units
is a function of the sample's percent solids. Percent solids range from less than 1% to 100% in NSSS
samples. A standardized reporting unit allows all sewage sludge samples to be evaluated on the same
basis with respect to pollutant loads. Implicit in this form of reporting is that pollutants are associated
with the solid phase of sewage sludge.
Dry weight and wet weight NSSS pollutant concentrations are plotted against percent solids for each of
the pollutants of concern in Figures 7-1 through 7-72. These graphics are located at the end of this
chapter. A density of 1 is assumed for conversions. Odd-numbered figures present dry weight pollutant
concentrations plotted against sample percent solids. Even-numbered figures present wet weight pollutant
concentrations plotted against sample percent solids. For a given pollutant, the wet weight plot generally
illustrates that pollutant concentrations detected above the minimum level tend to increase with increasing
percent solids. However, when dry weight concentrations for the same pollutant are plotted against
percent solids, this increasing trend is no longer evident. That is, dry weight pollutant concentrations
appear to be dispersed randomly with respect to percent solids. Since the conversion from wet to dry
weight concentration takes into account percent solids, this random dispersion of detected pollutant
concentrations reinforces the assertion that sewage sludge samples with differing percent solids can be
evaluated on the same basis with respect to pollutant load if dry weight measurements are used in the
analyses.
7-2
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Final Report
November 11, 1992
CHAP7.TSD
For any given pollutant, the values recorded under the variable "DETLIMIT" are not constant. A
constant value would imply that a fixed volume or amount was tested for all samples with no dilution of
the sample or extract and that there was no matrix effect. A matrix effect is defined as analytical
interference from the sewage sludge sample. This was not the case. All analytical protocols specified
the volume or amount of sewage sludge to be tested. However, when matrix interferences prevented
accurate determination of pollutant concentration, samples were diluted with reagent water and analyzed.
The purpose of dilution was to negate matrix effects. The minimum level for a diluted sample was raised
by the dilution factor, however. For instance, if a sample was diluted by a factor of 10, then the minimal
level was raised by a factor of 10. Analytical protocols provided explicit guidance as to the limits of
dilution.
Likewise, the reporting of analytical results in units per kilogram influences the values reported in the
data base. As mentioned previously, the percent solids of NSSS samples range from 1 to 100%. Because
the dry weight pollutant concentrations and minimum levels are a function of the percent solids in a
sample, the range in percent solids also is reflected in reported pollutant concentrations or minimum
levels. For example, assuming that there was no dilution of samples and that the same quantity of sewage
sludge was tested, the value recorded under "DETLIMIT" for a sample with 1 % solids would be 10 times
higher than that reported for a sample with 10% solids. This is because it would take 10 times the
quantity of the 1% solids sample to produce the same amount of solids in the 10% solids sample.
Figure 7-34 illustrates the wet weight of mercury for NSSS samples. Mercury concentrations detected
above the minimum level are distinguished by the triangle symbol and defined in the exhibit key as
"Above Minimum Level." This designation contrasts with the samples that were not measured above
the minimum level that are identified by the symbol "x" and are listed in the exhibit key as minimum
levels. Notice that the majority of "nondetect" samples have 0.01 mg/1 as the minimum level. The effect
of sample percent solids on the dry weight reporting of mercury minimum levels is illustrated by the plot
of dry weight mercury concentrations in Figure 7-33.
Because POTWs in the NSSS were sampled according to flow rate strata, a test was performed to
determine if there was a statistical association between flow rate group and a categorical variable created
from percent solids data. The three levels of the percent solids categorical variable were greater than
30% solids, between 1% and 30% solids, and less than 1% solids. These 3% solids categories were
selected to parallel the percent solids categories that differentiate sample preparation procedures in the
analytical protocols. The cross-tabulation of these two variables is listed in Table 7-1.
The statistical test of association incorporated the ordinal nature of both variables. Specifically, a test
statistic was calculated and a z-score determined from the difference in the number of concordant and
discordant pairs. The number of concordant and discordant pairs was determined according to the method
listed by Alan Agresti in his book entitled, Analysis of Ordinal Categorical Data (p. 180-181). Standard
error for the estimate of the difference in concordant and discordant pairs was derived using the delta
method under the assumption that the difference between concordant and discordant pairs is 0. This test
is a consistent test against monotonic departures from the null hypothesis that the two variables are
distributed independently.
7-3
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Final Report
November 11, 1992
CHAP7.TSD
TABLE 7-1.
FREQUENCY OF PERCENT SOLIDS IN NATIONAL SEWAGE SLUDGE SURVEY SAMPLES
BY FLOW RATE GROUP
Frequency
Percent
Row Pet
Col Pet
>100 MGD
10-100 MGD
1986 NEEDS based
Flow Rate
*-,
oup
1-10 MGD
<1 MGD
Percent Solids
>30%
4
34
14
8
26
25
11
31
35
i
7
34
24
Total
31
9
50
62
52
16
00
23
81
22
00
43
48
15
50
88
19
65
13
H_
22
73
35
_
22
62
34
t.
11
51
17
62
00 64
30%
J
17
.50
.38
.28
45
.50
.77
.16
44
.00
.86
.38
22
.00
.16
.19
<
0
0
0
1 » _
0
0
0
h_ _
2
5
40
h_
3
13
60
128
.00 5
1%
J
0
.00
.00
.00
0
.00
.00
.00
4
.00
.71
.00
6
.00
.95
.00
Total
26
13.00
61
30.50
70
35.00
43
21.50
10 200
.00 100.00
7-4
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Final Report
November 11, 1992
CHAP7.TSD
The calculated z-score from this test was 0.5675. The attained significance value for this statistic is more
than 0.5 but less than 0.9. Therefore, there is insufficient evidence to reject the null hypothesis that the
distribution of percent solids and flow rate group are independent.
7.2 PARAMETER ESTIMATION WITH CENSORED DATA
When a pollutant is not measured above the minimum level, the data point recording the dry weight
minimum level for that sample is considered "left censored." Left censoring implies that the pollutant
concentration in a sample falls within a restricted range. That is, the concentration in the sample is less
than, or "to the left of," the minimum-level value. When the censoring points (ie., dry weight minimum
levels) differ because of differences in the sewage sludge matrix, the data were considered to be
multicensored.
Several statistical methods are available for estimating pollutant concentration descriptive statistics when
the data contain multiple censor points. The most commonly applied methods include (1) ignoring the
censored observations, (2) setting all censored observations equal to 0, and (3) setting the censored
observation to either the minimum limit of detection or some fraction of the limit of detection. Ignoring
censored data will usually result in descriptive statistics that overestimate true pollutant concentration
values. Setting censored data points to 0 will underestimate true pollutant-concentration levels. Equating
censored points to the minimum level of detection will overestimate pollutant concentrations.
Other methods for estimating multicensored data exist but are used less frequently. Generally, these
methods consist of "fill-in" and maximum-likelihood procedures. "Fill-in" procedures replace censored
data points with pollutant concentrations that have been estimated from measured or noncensored data
points. In maximum-likelihood procedures developed by Cohen (1959), pollutant concentrations are
estimated by maximizing likelihood equations that incorporate both the data measured above the minimum
level and censored data point values. Eight procedures for calculating descriptive statistics from data with
a single censor point value were evaluated by Gilliom and Helsel of the U.S. Geological Survey (USGS)
in 1986. These procedures included simple substitution, "fill-in," and maximum-likelihood techniques.
Monte Carlo experiments with singularly censored data from distributions that mimic the distribution of
water quality measures were used to evaluate the accuracy and reliability of the eight methods.
Simulation results indicated that simple substitution methods produce biased and highly variable estimates.
The maximum-likelihood procedure and a probability plotting "fill-in " procedure, performed on natural
logarithm transformed data, produced the lowest errors of estimation. That is, estimated statistics were
the closest to the known population values. The most reliable estimates of the mean and standard
deviation were produced by the probability plotting procedure, while the maximum-likelihood technique
produced the best median and percentile estimates. Application of these techniques to actual water quality
data confirmed these conclusions.
In 1988, Helsel and Cohn of the USGS extended their study to include multiple censor points. Two
approaches to producing estimates were used in this later study. In the first approach, the maximum
value of the multiple censor points was determined, and single censor techniques were applied using this
maximum value. In the second approach, methods were evaluated using multiple censor points. The
methods using multiple censor points were shown to be better than the application of single censor
7-5
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Final Report
November 11, 1992
CHAP7. TSD
methods. Conclusions in the presence of multiple censor points were the same as those drawn from the
studies with single censor points. Although the "fill-in" procedure is more robust to departures from
lognormality, the maximum-likelihood technique is more desirable when lognormality of the distribution
of pollutants can be assumed. In their 1988 publication, Helsel and Cohn state, "When utilized correctly,
'less than' values frequently contain nearly as much information for estimating population moments and
quantiles as would the same observation had the detection limit been below them."
7.3 DATA CONVENTIONS AND SCHEMES
7.3.1 Conventions
Pollutant-concentration data were collected from 180 POTWs during the analytical component of the 1988
NSSS. However, data from only 178 POTWs were used for these estimates. Data from Episode 1477
are available at EPA's Sample Control Center, but were not included in the data set at the time of these
analyses. Data from Episode 1488 were determined to have been collected in 1989. Because the POTW
was not operational in 1988, trie data from this POTW were also excluded from these analyses. A listing
of these data, by survey stratum, for each of the pollutants of concern is found the appendix to this report
(in Volume II).
The national estimates were calculated for a total of 39 pollutants, including 11 metals, 7 organic
pollutants, 16 pesticides, individual and composite pollutants of concern, phosphorus, total jkeldahl
nitrogen, and percent solids. The composite pollutants consist of Aldrin/Dieldrin, DDT Composite
(DDD, DDE, and DDT), and the PCB Aroclors (PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-
1248, PCB-1254, and PCB-1260). Estimates were calculated for each of the composite pollutants and
each of the individual component pollutants.
Two sets of cadmium data were used in these analyses. A single cadmium concentration of 8,220 mg/kg
from Episode-1492 was determined to be an extreme value, since the next largest observed cadmium
concentration was 299 mg/kg. Therefore, the pollutant-concentration estimates for cadmium have been
calculated including and excluding this extreme concentration value.
The pollutant-concentration data have been aggregated by POTW for these analyses. For each of the 29
POTWs with samples from multiple treatment trains, the mean concentration was determined by weighing
each sample by the corresponding dry weight of sewage sludge disposed by the sample's treatment
process. There was insufficient information to link the samples for 23 of the 29 POTWs with samples
from multiple treatment trains with dry weight data. When the treatment process for each sample could
not be determined, an arithmetic average across treatment train samples was used. Therefore, the data
used for these estimates consists of a single pollutant concentration value per POTW for each pollutant.
If the pollutant concentration was detected above the minimum level for one sample from a POTW and
not detected above the minimum level for another sample from a POTW with multiple treatment trains,
the minimum-level value was used for the nondetected sample when POTW concentrations were
determined.
7-6
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Final Report
November 11, 1992
CHAP7.TSD
For the composite pollutants, the pollutant concentrations first were combined for each sample by
summing the individual concentrations together. The samples then were aggregated for each POTW as
stated above. This mathematical compositing was conducted because regulatory limits will be set for the
related pollutants as opposed to the individual component pollutant.
7.3.2 Adjusted Stratum Weights
Analytical survey stratum weights (w;) used to calculate national estimates have been adjusted to exclude
the POTWs determined to have been INELIGIBLE or OUT OF BUSINESS in 1988 or classified as using
wastewater stabilization ponds. The total number of POTWs (N;) within each survey flow rate stratum,
and the number of POTWs selected for the analytical survey (r$ are tabulated below.
NUMBER OF POTWs IN THE NSSS ANALYTICAL SURVEY
Stratum
1 - Flow > 100 MGD
2 - 10 < Flow < 100 MGD
3 - 1 < Flow < 10 MGD
4 - Flow < 1 MGD
Total
NI
28
324
1,927
9.067
11,346
«i
20
56
65
67
208
Five POTWs in the analytic survey were classified as INELIGIBLE or OUT OF BUSINESS in 1988. In
addition to these five, there were eighteen POTWs classified as using Wastewater Stabilization Ponds.
POTWs using wastewater stabilization ponds as a form of secondary treatment are excluded from national
estimates of pollutant concentration because no sewage sludge samples were obtained from this treatment
process during the NSSS analytical survey. Samples were not obtained from the POTWs due to sampling
difficulty and because secondary treatment was not complete. The adjusted number of eligible POTWs
in the Nation (N;) and the number of POTWs sampled (HJ), after excluding these POTWs, along with the
adjusted stratum weights (w-), are presented below.
ADJUSTED NUMBER OF ELIGIBLE POTWs
Stratumi Ni
1
2
3
4
- Flow
= 10 <
> 100 MGD
Flow < 100 MGD
- 1 < Flow < 10 MGD
= Flow
< 1 MGD
Total
1
6
8
27
318
,927
.225
,497
"i
19
55
65
46
185
Stratum
27/8
318/8
1 , 927/8
6,225/8
,497
,497
,497
,497
Weights=wi
- 0
= 0
= 0
= 0
1
.00318
.03742
.22679
.73261
.00000
7-7
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Final Report
November 11, 1992
CHAP7.TSD
The total number of eligible POTWs sampled was 185. However, pollutant-concentration data were
available for only 178 POTWs. The remaining seven POTWs were considered eligible for the analytic
survey, according to the disposal practices listed in the questionnaire responses, but six could not be
sampled due to logistic difficulties, and data from the seventh was not added to the data base. For the
calculation of the national pollutant-concentration estimates, it is assumed that these POTWs operate at
the stratum mean concentration level.
7.4 POTW-BASED NATIONAL POLLUTANT-CONCENTRATION ESTIMATES
National estimates of POTW-based pollutant concentrations are presented in this section. Descriptive
statistics for pollutant concentrations are generated from the distribution of pollutant concentrations across
all POTWs in the Nation. Thus, the mean pollutant concentration in the Nation is actually the expected
concentration of the given pollutant in sewage sludge from the "average" POTW. The concentration of
a given pollutant in sewage sludge from 90% of the POTWs in the Nation will be less than or equal to
the estimated 90* percentile pollutant concentration.
The first set of estimates presented in this chapter were generated under the assumption that pollutant
concentrations in sewage sludge follow a lognormal distribution. Statistical methods and strata and
national estimates of pollutant-concentration means, standard deviations, and coefficients of variation
under this distributional assumption are presented in section 7.4.1.
As a point of reference, two nonparametric statistical estimates of pollutant concentrations for the
pollutants of concern are tabulated along with estimates, which were generated under the assumption that
pollutant concentrations follow a lognormal distribution. Nonparametric statistical estimation procedures
do not make any assumptions about the distribution of pollutant concentrations in sewage sludge. For one
nonparametric estimate, sample-specific minimum-level values were substituted for those samples from
which a pollutant concentration was not measured above the minimum level of detection. The value of
zero was substituted for those samples from which a pollutant concentration was not measured above the
minimum level of detection in the other nonparametric estimates.
Nonparametric and lognormal national estimates of pollutant concentrations are presented in section 7.4.2.
Estimates include the mean, standard deviation, and coefficient of variation of pollutant concentrations
in the Nation for the pollutants of concern and 95% confidence intervals about the estimated national
mean pollutant concentrations—the latter are included in this document in response to public request.
Finally, section 7.4.3 presents the statistical methodology and results for nonparametric and lognormal
estimates of the 50th, 90th, 95th, 98th, and 99* percentile pollutant concentrations.
Three significant figures are reported for all pollutant-concentration estimates. To maintain a consistent
format, tabulated estimates include two decimal places. If these digits are not significant, zeros are
reported.
7-8
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Final Report
November 11, 1992
CHAP7.TSD
7.4.1 National Pollutant-Concentration Estimates—Assuming Pollutant Concentrations Follow a
Lognormal Distribution
Pollutant concentration descriptive statistics for the NSSS were estimated as weighted functions of
estimates from each of the four flow rate strata in the survey design. Stratum estimates were produced
using the multiple censor point, maximum-likelihood technique. This technique, which requires the
assumption that pollutant concentrations follow a lognormal distribution, was the statistical method of
choice for two reasons: (1) the lognormal distribution is commonly used because it generally provides
a good approximation of the distribution of pollutant concentrations, and (2) there was an insufficient
number of samples detected above the minimum level to use the "fill-in" technique for some strata.
For the i* flow rate stratum, maximum-likelihood estimates (MLE) of the mean (/*;) and variance
of pollutant concentration were obtained by minimizing the following loss function:
LOSS,
-ft
Note that minimizing this loss function is tantamount to maximizing the likelihood function. In the loss
function expression, ln(X^) is the natural logarithm transform of the pollutant concentration for the j*
sample from the i* stratum. The first indicator function I(Xjj > ML;j) takes on the value 1 if the
pollutant concentration from the j* sample from the i* flow rate stratum is greater than the minimum
level, and 0 if otherwise. The second indicator function, l(X$ ^ ML;j), has a value of 1 if the pollutant
concentration hi the ij* sample is not measured above the minimum level, and 0 if it is. Therefore,
observations above the minimum level enter the loss function in the standard fashion. On the other hand,
censored observations contribute to the loss function through the lognormal cumulative distribution
function.
Iterative techniques were used to determine values of the mean 0*;) and variance (a2j) that minimize the
loss function for pollutant concentrations from the i* stratum. The first technique, known as the Simplex
algorithm, employs direct search techniques and does not require a Hessian matrix of second derivatives
to determine the step direction of each iteration. The second technique, the Quasi-Newton algorithm,
makes use of information in the Hessian matrix. Quasi-Newton algorithms approximate the Hessian
matrix at each iteration. A singular or nondefined Hessian matrix precludes parameter estimation.
Several runs were made using both of these minimization techniques to estimate the MLE concentrations
for each stratum. The runs differed in the values of the mean and variance supplied to the algorithms
as starting points. Regardless of the starting points, the same MLEs were produced from each run
7-9
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Final Report
November 11, 1992
CHAP7. TSD
provided that the stratum had at least one noncensored data point. That is, for a given pollutant*stratum,
the same MLEs resulted from both minimization techniques from each series of starting values. When
all data points were censored, the resulting MLEs were not unique. These estimates are listed as missing.
Functions of the maximum-likelihood mean and variance estimates for each pollutant*stratum were
exponentiated to determine the mean, or expected concentration value of X; and the variance of X;. The
variable X; designates pollutant concentration from the 1th flow rate stratum from the survey design.
Again, Xj is assumed to be distributed lognormally. For a given pollutant, the expected pollutant
concentration E(Xj) and variance V(X-) for each stratum were estimated as follows:
E(Xi) =
V(X±) = expUAj+d2,) (exp(d2i)-l) .
A A
In this expression, /^ is the MLE of the i stratum mean, and
-------
Final Report
November 11, 1992
CHAP7.TSD
Pollutant-concentration variance V(X) was estimated as a function of within- and between-strata variance
components. The estimator used for NSSS pollutants will be motivated first by an expression of the
unbiased estimate of population variance based on proportional stratified sampling. This expression,
listed in Sampling Survey Methods and Theory, Vol. II (Hansen, Hurwitz, and Madow. p. 138), is
- i> B* . -^
v(x) = ^
n
where
The subscript h designates the stratum while the subscript i indicates the i* observation in the stratum.
S2wX defines the weighted sum of within-stratum variances for the random variable X.
Under proportional stratified sampling
~n ~ ~N
where n,, is the number of POTWs sampled for stratum h and n is the sum of POTWs sampled over all
strata. Likewise, Nh is the number of elements in the sampling frame stratum and N is the total number
of elements in the sampling frame. N is obtained by summing Nh over all strata.
The sampling fraction, fh, is the same for all strata under proportional stratification since for every
stratum
n N Nh N
Therefore,
_
n N nh
7-11
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Final Report
November 11, 1992
CHAP7. TSD
can be expressed as
1
n
The variance, V(X), for a stratified sample becomes
The first term in this variance expression can be written as
rz-?
h. i-l nh
which equals
After combining like terms, the variance estimate is written as
L w L _
where
nb 1 ~
Q2 = V* k*
6 hx L TT^i
1^1 11h J
defines the within-stratum variance component. The second term in the expression for the variance
estimator is the between-strata sums of squares.
7-12
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Final Report
November 11, 1992
CHAP7.TSD
Therefore, pollutant-concentration variance was estimated from the NSSS as
* v 4
V(X) = V V(X±)—± (n.-i+vAl-f,)) + y w1(E(X,)-E(X))2.
£i * *i K
Table 7-2 presents stratum and national pollutant-concentration estimates for the pollutants of concern.
Individual pollutant estimates for the mathematically composited pollutants are presented in Table 7-3.
Finally, stratum and national MLE estimates for Total Kjeldahl Nitrogen and Phosphorus are provided
in Table 7-4.
7.4.2 Lognormal and Nonparametric Pollutant-Concentration Estimates
Due to the extremely low levels of detection, national estimates are not available for some pollutants
under the parametric assumption that pollutant concentration follows a lognormal distribution.
Nonparametric estimates do not require any distributional assumptions. Because of this, estimates can be
generated for all pollutants. Nonparametric national estimates of pollutant concentration were calculated
using two substitution methods for those samples from which a pollutant was not quantified above the
minimum level of detection. In the first method, sample-specific values of the minimum level of detection
were substituted for those samples from which a pollutant was not quantified above the minimum level
of detection. Estimates produced according to this method are designated as "SM-ML." In the second
nonparametric method, the value zero was substituted for those samples from which a pollutant was not
quantified above the minimum level of detection. Estimates produced using this method are designated
as "SM-0." Although these nonparametric methods yield estimates for all pollutants regardless of the rate
of detection, the reader is cautioned to refer to the discussion in Section 7.2 regarding the pollutant
statistical properties related to estimates resulting from these substitution methods.
7-13
-------
TABLE 7-2.
STRATA AW) NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
ASSUMING A LOGNORNAL DISTRIBUTION OF CONCENTRATION
POLLUTANTS OF CONCERN
Number of
Pollutant Unit Stratum POTWs
Aldrin/Dieldrirr M9/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
Aldrin/Dieldrin"* M9Ag > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
Aldrin/DieldrinM M9/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
Arsenic mg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
19
54
64
41
178
Detect
Percent
0
0
0
0
0
11
4
10
7
8
11
4
10
7
8
74
91
86
78
80
Mean
.
.
•
5.45
14.50
6.03
6.41
6.63
8.83
4.38
7.40
5.68
6.03
8.33
10.60
9.63
9.43
9.52
Standard
Deviation
•
28.20
17,300.00
67.10
210.00
3,320.00
11.60
59.80
15.20
24.10
24.70
4.82
12.60
10.20
18.80
16.90
Coefficient of
Variation (CV)
•
5.18
1,200.00
11.10
32.70
501.00
1.32
13.70
2.06
4.24
4.09
0.58
1.19
1.06
1.99
1.78
= Nonestimable.
* . = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
• Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
" Composite Pollutant Considered a Detect if At Least One Individual Pollutant is Measured Above the Minimum Level.
' Composite Pollutant Concentration Determined by Setting Maximum Nondetect Equal to the Highest Minimum Value and All Other Nondetects to Zero.
' Composite Pollutant Concentration Determined by Setting Nondetect Equal to the Minimum Level.
Note: Aldrin/DeiIdrin is a combination of Aldrin and Dieldrin.
-------
TABLE 7-2. (Continued)
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM TIE NATIONAL SEWAGE SLUDGE SURVEY
ASSUMING A LOGNORMAL DISTRIBUTION OF CONCENTRATION
POLLUTANTS OF CONCERN
l/i
Pollutant Unit
Benzene pg/kg
Benzo(A)pyrene pg/kg
Beryllium mg/kg
Bis(2-Ethylhexyl) Phthalate i»g/kg
Cadmium mg/kg
St ratun
> 100 MOD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
> 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
> 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
> 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
> 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
Number of
POTWs
19
54
64
41
178
19
54
64
41
178
19
54
64
41
178
19
54
64
41
178
19
54
64
41
178
Detect
Percent
11
4
0
0
0
0
6
5
2
3
37
24
38
17
22
100
85
89
54
63
89
100
81
63
69
Mean
98.80
16.30
m
m
•
f
427.00
268.00
•
0.51
0.38
0.52
0.34
0.38
160,000.00
157,000.00
145,000.00
46,900.00
73,600.00
52.10
22.30
16.40
5.48
8.74
Standard Coefficient of
Deviation Variation (CV)
2,700.00
305.00
.
•
•
.
2,770.00
429.00
•
0.14
0.34
0.47
0.36
0.39
415,000.00.
411,000.00
648,000.00
399,000.00
468,000.00
98.60
39.20
38.00
6.36
21.80
27.30
18.70
*
6.48
1.60
•
0.27
0.89
0.90
1.07
1.03
2.60
2.62
4.47
8.50
6.36
1.89
1.76
2.32
1.16
2.49
. = Nonestimable.
* = National Estimates Determined as Weighted Suns of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
-------
TABLE 7-2. (Continued)
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEUAGE SLUDGE SURVEY
ASSUMING A LOGNORMAL DISTRIBUTION OF CONCENTRATION
POLLUTANTS OF CONCERN
Pollutant
Cadmium*
Chlordane
Chromium
Copper
Unit Stratum
mg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
|ig/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
mg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
mg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
Number of
POTWs
19
54
63
41
177
19
54
63
41
177
19
54
64
/. 1
178
19
54
64
41
178
Detect
Percent
89
100
81
63
69
0
0
2
0
0
100
100
100
88
91
100
100
100
100
100
Mean
52.10
22.30
9.52
5.48
7.18
.
23.10
480.00
254.00
189.00
95.50
124.00
901.00
746.00
628.00
752.00
724.00
Standard (
Deviation \
98.60
39.20
11.40
6.36
12.80
403.00
•
596.00
437.00
363.00
302.00
327.00
758.00
629.00
489.00
1,020.00
909.00
:oefficient of
'ariation (CV)
.89
.76
.20
.16
.78
17i40
•
1.24
1.72
1.92
3.17
2.64
0.84
0.84
0.78
1.35
1.25
= Nonestimable.
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
• Estimates Generated After Deleting an Extreme Outlier Observation from Stratum 3.
-------
TABLE 7-2. (Continued)
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEIMGE SLUDGE SURVEY
ASSUMING A LOGNORNAL DISTRIBUTION OF CONCENTRATION
POLLUTANTS OF CONCERN
Pollutant
DDT, Composite*
DDT, Composite"
DDT, Composite"
Heptachlor
Unit Stratum
tig/kg > 100 MOD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
iig/kg > 100 HGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
tig/kg > 100 MGO
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
M9/kg > 100 HGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
Number of
POTWs
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
Detect
Percent
0
0
0
0
0
21
6
5
2
3
21
6
5
2
3
0
2
0
0
0
Mean
•
.
.
•
71.70
13.10
11.30
5.39
7.22
91.40
33.50
31.80
13.50
18.60
3.32
.
.
Standard Coefficient of
Deviation Variation (CV>
•
553.00
62.50
54.40
15.60
43.90
209.00
48.00
33.70
23.70
31.10
4.73
•
7.71
4.76
4.83
2.90
6.08
2.28
1.43
1.06
1.76
1.67
1.42
= Nonestimable.
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
• Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
* Composite Pollutant Considered a Detect if At Least One Individual Pollutant is Measured Above the Minimum Level.
• Composite Pollutant Concentration Determined by Setting Maximum Nondetect Equal to the Highest Minimum Value and All Other Nondetects to Zero
1 Composite Pollutant Concentration Determined by Setting Nondetect Equal to the Minimum Level.
Note: DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDE, and 4,4'-DDT.
-------
TABLE 7-2. (Continued)
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEUAGE SLUDGE SURVEY
ASSUMING A LOGNORMAL DISTRIBUTION OF CONCENTRATION
POLLUTANTS OF CONCERN
-J
oo
Pollutant
Hexach I orobenzene
Hexachlorobutadiene
Lead
Lindane (Gamma-BHC)
Mercury
Unit Stratum
M9/kg > 100 MGD
10 < FLOW <=
1 < FLOW <=
FLOW <=
NATIONAL*
M9/kg > 100 MGD
10 < FLOW <=
1 < FLOW <=
FLOW <=
NATIONAL*
mg/kg > 100 MGD
10 < FLOW <=
1 < FLOW <=
FLOW <=
NATIONAL*
Mg/kg > 100 MGD
10 < FLOW <=
1 < FLOW <=
FLOW <=
NATIONAL*
mg/kg > 100 MGD
10 < FLOW <=
1 < FLOW <=
FLOW <=
NATIONAL*
Number of
POTWs
100
10
1
100
10
1
100
10
1
100
10
1
100
10
1
19
54
64
41
178
19
54
64
41
178
19
54
64
41
178
19
54
63
41
177
19
54
64
41
178
Detect
Percent
0
0
0
0
0
0
0
0
0
0
100
100
89
76
80
0
2
2
0
0
84
87
84
56
64
Mean
•
•
245.
241.
158.
117.
131.
2.
2.
f
•
2.
2.
4.
5.
5.
00
00
00
00
00
68
41
66
98
14
78
30
Standard Coefficient of
Deviation Variation (CV)
•
•
159.
284.
147.
179.
179.
28.
54.
.
•
1.
2.
3.
18.
16.
00
00
00
00
00
80
20
83
61
25
90
30
0
1
0
1
1
10
22
0
0
0
3
3
•
•
.65
.18
.93
.53
.36
.70
.50
.
•
.69
.88
.78
.27
.07
. = Nonestimable.
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
-------
TABLE 7-2. (Continued)
STRATA AM) NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
ASSUMING A LOGNORNAL DISTRIBUTION OF CONCENTRATION
POLLUTANTS OF CONCERN
Pollutant
Molybdenum
N-Nitrosodimethylamine
Nickel
PCB, Composite-
Number of
Unit Stratum POTWs
mg/kg > 100 HGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
i»g/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
mg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
Mg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
19
54
64
41
178
19
54
64
41
178
19
54
64
41
178
19
54
63
41
177
Detect
Percent
68
80
69
46
53
0
0
0
0
0
95
98
83
61
67
0
0
0
0
0
Mean
9.42
12.80
10.60
9.16
9.63
B
B
.
•
104.00
82.80
48.90
42.90
46.00
.
f
,
,
Standard Coefficient of
Deviation Variation (CV)
6.43
16.20
10.80
18.70
17.10
.
.
•
124.00
115.00
48.60
114.00
103.00
f
.
a
0.68
1.26
1.01
2.05
1.78
•
1.19
1.39
0.99
2.66
2.24
\
. = Nonestimable.
* = National Estimates Determined as Weighted Suns of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
• Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1332, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-2. (Continued)
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEUAGE SLUDGE SURVEY
ASSUMING A LOGHORMAL DISTRIBUTION OF CONCENTRATION
POLLUTANTS OF CONCERN
--J
I
o
Pollutant
PCB, Compos i te**
PCB, Composite"
Selenium
Toxaphene
Number of
Unit Stratum POTWs
iig/kg > 100 MGO
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
Mg/kg > 100 MGO
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
mg/kg > 100 HGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <- 1
NATIONAL*
Mg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
19
54
63
41
177
19
54
63
41
177
19
54
64
41
178
19
54
63
41
177
Detect
Percent
21
15
19
20
19
21
15
19
20
19
68
87
78
XI
u_r
68
0
0
0
0
0
Mean
472.00
415.00
471.00
1,600.00
1.300.00
1,050.00
737.00
802.00
923.00
889.00
6.11
5.25
7.12
5.12
5.58
f
.
a
Standard
Deviation
5,540.00
12,700.00
8,600.00
182,000.00
155,000.00
525.00
701.00
721.00
2,780.00
2,400.00
7.11
4.93
7.38
8.10
7.86
.
m
.
Coefficient of
Variation (CV)
11.70
30.70
18.30
114.00
120.00
0.50
0.95
0.90
3.01
2.70
1.16
0.94
1.04
1.58
1.41
_
t
= Nonestimable.
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
• Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
' Composite Pollutant Considered a Detect if At Least One Individual Pollutant is Measured Above the Minimum Level.
• Composite Pollutant Concentration Determined by Setting Maximum Nondetect Equal to the Highest Minimum Value and All Other Nondetects to Zero.
1 Composite Pollutant Concentration Determined by Setting Nondetect Equal to the Minimum Level.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1332, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-2. (Continued)
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
ASSUMING A LOGNORNAL DISTRIBUTION OF CONCENTRATION
POLLUTANTS OF CONCERN
Pollutant
Unit
Stratum
Number of
POTUs
Detect
Percent
Mean
Standard
Deviation
Coefficient of
Variation (CV)
Trichloroethene
eg/kg
> 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL*
19
54
64
41
178
5
6
5
0
1
10.80
49.60
21,900.00
10.10
2,720.00
33,900,000,000.00
0.93
54.80
1,540,000.00
Zinc
mg/kg > 100 MGD 19 100
10 < FLOW <= 100 54 100
1 < FLOW <= 10 64 100
FLOW <= 1 41 100
NATIONAL* 178 100
1,470.00
1,520.00
1,700.00
1,060.00
1,220.00
859.00
1,550.00
2,260.00
1,280.00
1,580.00
0.59
1.02
1.33
1.21
1.30
. = Nonestimable.
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
-------
TABLE 7-3.
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
ASSUMING A LOGNORMAL DISTRIBUTION OF CONCENTRATION
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
--J
to
Number of
Pollutant Unit Stratum POTWs
Aldrin/Dieldrirr |ig/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
Aldrin/Dieldrin" ^g/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
Aldrin/Dieldrin"* M9/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
Aldrin )ig/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
Detect
Percent
0
0
0
0
0
11
4
10
7
8
11
4
10
7
8
5
4
5
2
3
Mean
.
m
•
5.45
14.50
6.03
6.41
6.63
8.83
4.38
7.40
5.68
6.03
2.81
6.35
2.42
1.55
1.93
Standard
Deviation
.
.
m
•
28.20
17,300.00
67.10
210.00
3.320.00
11.60
59.80
15.20
24.10
24.70
5.02.
1,480.00
19.60
54.30
289.00
Coefficient of
Variation (CV)
.
.
•
5.18
1,200.00
11.10
32.70
501.00
1.32
13.70
2.06
4.24
4.09
1.78
234.00
8.07
35.10
150.00
. = Nonestimable.
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
• Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
» Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
c Composite Pollutant Concentration Determined by Setting Maximum Nondetect Equal to the Highest Minimum Value and All Other Nondetects to Zero.
' Composite Pollutant Concentration Determined by Setting Nondetects Equal to the Minimum Level.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
-------
TABLE 7-3. (Continued)
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
ASSUMING A LOGNORNAL DISTRIBUTION OF CONCENTRATION
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
K)
U)
Pollutant
Dieldrin
DDT, Composite*
DDT, Composite"
DDT, Composite"
Number of
Unit Stratum POTWs
pg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
M9/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
(•g/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
tig/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
Detect
Percent
5
0
5
5
5
0
0
0
0
0
21
6
5
2
3
21
6
5
2
3
Mean
3.00
B
2.56
3.23
•
.
t
'
•
71.70
13.10
11.30
5.39
7.22
91.40
33.50
31.80
13.50
18.60
Standard Coefficient of
Deviation Variation (CV)
22.30
.
25.50
80.50
•
_
•
•
553.00
62.50
54.40
15.60
43.90
209.00
48.00
33.70
23.70
31.10
7.43
_
9!96
24.90
•
.
•
7.71
4.76
4.83
2.90
6.08
2.28
1.43
1.06
1.76
1.67
. = Nonestimable.
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
* Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
b Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
° Composite Pollutant Concentration Determined by Setting Maximum Nondetect Equal to the Highest Minimum Value and All Other Nondetects to Zero.
" Composite Pollutant Concentration Determined by Setting Nondetects Equal to the Minimum Level.
Note: DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDE, end 4,4'-DDT.
-------
TABLE 7-3. (Continued)
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEUAGE SLUDGE SURVEY
ASSUMING A LOGNORNAL DISTRIBUTION OF CONCENTRATION
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
to
Pollutant
4, 4' -ODD
4,4'-DDE
4,4'-DDT
PCB, Composite1
Number of
Unit Stratum POTUs
tig/kg > 100 HGO
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
Mg/kg > 100 HGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
Mg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
ng/kg > 100 HGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
Detect
Percent
5
0
C
0
0
5
2
3
0
1
16
4
2
2
2
0
0
0
0
0
Mean
1,260.00
f
.
•
42.30
14.50
7.83
t
•
11.60
11.00
1.82
2.15
2.44
.
m
.
Standard Coefficient of
Deviation Variation (CV)
42.400,000.00 33,700.00
•
4,600.00 109.00
7.85 0.54
29.20 3.73
_
•
22.10 1.91
1,940.00 176.00
9.13 5.02
6.55 3.05
371.00 152.00
.
.
= Nonestimable.
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
• Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-3. (Continued)
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROH THE NATIONAL SEUAGE SLUDGE SURVEY
ASSUMING A LOGNORNAL DISTRIBUTION OF CONCENTRATION
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
to
Ul
Pollutant
PCB, Composite"
PCS, Compos iteM
PCB- 1016
PCB- 1221
Number of
Unit Stratum POTUs
(ig/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
M9/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
iig/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
lig/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
Detect
Percent
21
15
19
20
19
21
15
19
20
19
0
0
0
0
0
0
0
0
0
0
Mean
472.00
415.00
471.00
1.600.00
1,300.00
1.050.00
737.00
802.00
923.00
889.00
•
m
m
m
•
.
m
.
Standard
Deviation
5,540.00
12,700.00
8,600.00
182,000.00
155,000.00
525.00
701 .00
721.00
2,780.00
2,400.00
.
•.
_
•
_
.
Coefficient of
Variation (CV)
11.70
30.70
18.30
114.00
120.00
0.50
0.95
0.90
3.01
2.70
_
.
•
•
. = Nonestimable.
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
" Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
• Composite Pollutant Concentration Determined by Setting Maximum Nondetect Equal to the Highest Minimum Value and All Other Nondetects to Zero.
' Composite Pollutant Concentration Determined by Setting Nondetects Equal to the Minimum Level.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-3. (Continued)
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
ASSUMING A LOGNORNAL DISTRIBUTION OF CONCENTRATION
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
K)
ON
Pollutant
PCB-1232
PCB-1242
PCB-1248
PCB-1254
PCB-1260
Number of
Unit Stratum POTWs
M9/kg > 100 MGD
10 < FLOW <= 100
1 <• FLOW <= 10
FLOW <= 1
NATIONAL
l>g/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
Mg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
Mg/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
M9/kg > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
19
54
63
41
177
Detect
Percent
0
0
0
0
0
0
0
0
0
0
11
11
13
7
9
5
2
6
10
9
16
7
10
10
10
Mean
_
.
.
•
.
f
f
•
91.20
201.00
144.00
47.40
75.10
2,740.00
47.30
79.60
36.100.00
26,500.00
147.00
66.40
105.00
120.00
115.00
Standard
Deviation
•
.
.
•
139.00
4,260.00
1,060.00
118.00
965.00
33,800,000.00
10,700.00
1,120.00
2,920,000,000.00
2,490,000,000.00
433.00
133.00
841.00
1,940.00
1,710.00
Coefficient of
Variation (CV)
•
m
•
1.52
21.10
7.39
Z.SO
12.80
12,300.00
227.00
14.10
80,700.00
94,000.00
2.95
2.00
7.97
16.20
14.90
= Nonestimable.
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
-------
TABLE 7-4.
STRATA AND NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEUAGE SLUDGE SURVEY
ASSUMING A LOGNORNAL DISTRIBUTION OF CONCENTRATION
PERCENT SOLIDS. PHOSPHORUS, AND TOTAL KJELDAHL NITROGEN
-J
to
Pol lutant
Percent Solids
Phosphorus
Total Kjeldahl Nitrogen
Number of
Unit Stratum POTUs
X > 100 MGO
10 < FLOW <= 100
1 < FLOW <= 10
FLOW « 1
NATIONAL
mg/kg > 100 MOD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
mg/kg > 100 HGO
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
NATIONAL
19
54
64
41
178
19
54
64
41
178
19
54
64
41
178
Detect
Percent
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
Mean
26.70
26.60
33.80
30.10
30.80
2.510.00
1.630.00
4,800.00
8,140.00
7,120.00
63,700.00
69,500.00
53,300.00
48,100.00
50,100.00
Standard Coefficient of
Deviation Variation (CV)
52.90
34.60
97.70
138.00
126.00
4,660.00
3,770.00
23,300.00
48,700.00
43,100.00
77.100.00
124,000.00
66,400.00
56,800.00
62,800.00
1.98
1.30
2.89
4.57
4.11
1.86
2.31
4.84
5.99
6.06
1.21
1.78
1.25
1.18
1.25
* = National Estimates Determined as Weighted Sums of Stratum Estimates.
CV = Standard Deviation Divided by the Mean.
-------
Final Report
November 11, 1992
CHAP7. TSD
Once substitutions were made for censored data points, stratum estimates of the expected value of
pollutant concentration E(X;) and variance V(Xj) were generated arithmetically. That is, the stratum
estimate of E(X;) was calculated as
and the variance of the pollutant concentration for the r* stratum V(Xi) as
The variable X;j indicates the pollutant concentration value from the j* POTW sampled in the i"1 stratum.
Likewise, ri; designates the number of POTWs sampled in the i* flow rate stratum.
National, nonparametric pollutant concentrations means and variances are then estimated using the
formulae for the respective national estimates presented in section 7.4.1.
Table 7-5 lists lognormal and nonparametric national estimates of the mean, standard deviation, and
coefficient of variation for the pollutants of concern. Estimates designated as "MLE" indicate that the
national estimate was generated under the assumption that pollutant concentrations follow a lognormal
distribution. National estimates for the individual pollutants for those pollutants which have been
mathematically composited are presented in Table 7-6.
Finally, parametric and nonparametric estimates of the mean, standard deviation, and coefficient of
variation for total kjeldahl nitrogen and phosphorus are listed in Table 7-7.
7-28
-------
TABLE 7-5.
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORHAL AND NONPARANETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation
Coefficient
of Variation (CV)
Aldrin/Dieldrin-
ng/kg
HLE
SM-HL
SH-0
SM-COM
26.70
1.65
14.40
27.00
6.44
14.40
1.01
3.90
1.00
Aldrin/Dieldrin*
i«g/kg
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
6.03
6.63
26.70
1.65
14.40
24.70
,320.00
27.00
6.44
14.40
4.09
501.5
1.01
3.90
1.00
-J
to
Arsenic
ing/kg
80
MLE
SM-ML
SM-0
9.52
10.30
8.66
16.90
14.90
14.70
1.78
1.44
1.70
Benzene
MLE
SM-ML
SM-0
956.00
0.08
2,830.00
3.37
2.96
44.95
MLE s Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Honestimable.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
-------
TABLE 7-5. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEUAGE SLUDGE SURVEY
USING LOGNORNAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
POLLUTANTS OF CONCERN
OJ
o
Percent
Pollutant Unit Detect
Benzo(A)pyrene eg/kg 3
Beryllium mg/kg 22
Bis(2-Ethylhexyl) Phthalate (ig/kg 63
Cadmium mg/kg 69
Cadmiunf mg/kg 69
Chlordane Mg/kg 0
Chromium mg/kg 91
Estimation
Procedure*
MLE
SM-HL
SM-0
HLE
SM-HL
SM-0
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
Mean
9,620.00
76.90
0.38
1.85
0.12
73,600.00
54,000.00
48,600.00
8.74
39.40
36.00
7.18
10.30
6.96
321.00
1.76
124.00
163.00
160.00
Standard
Deviation
13,100.00
1,100.00
0.39
2.43
0.28
468,000.00
106,000.00
107,000.00
21.80
489.00
490.00
12.80
26.20
26.20
338 ! 00
29.30
327.00
438.00
439.00
Coefficient
of Variation (CV)
K36
14.28
1.03
1.31
2.27
6.36
1.96
2.21
2.49
12.42
13.58
1.78
2.53
3.77
1.05
16.67
2.64
2.69
2.74
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
Estimates Generated After Deleting an Extreme Outlier Observation from Stratum 3.
= Nonestimable.
-------
TABLE 7-5. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEUAGE SLUDGE SURVEY
USING LOGNORNAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation
Coefficient
of Variation (CV)
Copper
mg/kg
100
HLE
SM-HL
SM-0
724.00
657.00
657.00
909.00
568.00
568.00
1.25
0.87
0.87
DDT, Composite1
eg/kg
HLE
SM-ML
SM-0
SM-COH
154.00
1.24
65.30
162.00
12.30
68.10
1.05
9.97
1.04
DDT, Composite*
u>
HLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
18.60
7.22
154.00
1.24
65.30
31.10
43.90
162.00
12.30
68.10
1.67
6.08
1.05
9.97
1.04
Heptachlor
M9/kg
MLE
SM-ML
SM-0
25.60
0.02
27.00
0.59
1.06
38.00
* MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs.
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level- Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Note: DDT, Composite is a combination of 4,4'-DDO, 4,4'-DDE, and 4,4'-DDT.
-------
TABLE 7-5. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
POLLUTANTS Of CONCERN
OJ
K)
Percent
Pollutant Unit Detect
Hexachlorobenzene pg/kg 0
Hexachlorobutadiene eg/kg 0
Lead mg/kg 80
Lindane (Gamma-BHC) M9/kg 0
Mercury mg/kg 64
Molybdenum mg/kg 53
N-Nitrosodimethylamine i>g/kg 0
Estimation
Procedure*
MLE
SM-HL
SM-0
HLE
SM-ML
SM-0
MLE
SM-HL
SM-0
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
Mean
9,560.00
0.00
9,560.00
0.00
131.00
135.00
109.00
32.30
0.16
5.30
6.58
3.83
9.63
14.70
6.66
47,800.00
0.00
Standard
Deviation
13,100.00
0.00
13,100.00
0.00
179.00
122.00
128.00
33.80
2.46
16.30
8.77
8.48
17.10
14.50
11.80
65,400.00
0.00
Coefficient
of Variation (CV)
1.37
0.00
1.37
0.00
1.36
0.91
1.18
1.05
15.26
3.07
1.33
2.21
1.78
0.98
1.78
l!37
0.00
* MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
= Honestimable.
-------
TABLE 7-5. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORNAL AND HONPARANETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation
Coefficient
of Variation (CV)
Nickel
mg/kg
67
MLE
SM-HL
SM-0
46.00
58.20
44.00
103.00
95.10
97.60
2.24
1.63
2.22
PCB, Composite*
eg/kg
MLE
SH-ML
SM-0
SM-COM
2,030.00
279.00
535.00
2,070.00
992.00
1,010.00
1.02
3.56
1.89
PCB, Composite*
l>9/kg
19
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
889.00
1,300.00
2,030.00
279.00
535.00
2,400.00
155,000.00
2,070.00
992.00
1,010.00
2.70
119.8
1.02
3.56
1.89
Selenium
mg/kg
68
MLE
SM-ML
SM-0
5.58
7.70
4.28
7.86
11.10
8.09
1.41
1.45
1.89
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-5. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation
Coefficient
of Variation (CV)
Toxaphene
eg/kg
MLE
SM-HL
SM-0
1,280.00
0.00
1,350.00
0.00
1.06
0.00
Trichloroethene
MLE
SM-ML
SM-0
968.00
17.10
2,SAO.00
212.00
2.93
12.37
Zinc
mg/kg
100
MLE
SM-ML
SM-0
1,220.00
1,430.00
1,430.00
1,580.00
4,560.00
4,560.00
1.30
3.19
3.19
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
= Nonestimable.
-------
TABLE 7-6.
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation
Coefficient
of Variation (CV)
Aldrin/Dieldrirr
MLE
SN-ML
SM-0
SM-COM
26.70
1.65
14.40
27.00
6.44
14.40
1.01
3.90
1.00
Aldrin/Dieldrin*
ng/kg
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
6.03
6.63
26.70
1.65
14.40
24.70
3,320.00
27.00
6.44
14.40
4.09
501.0
1.01
3.90
1.00
Aldrin
i>g/kg
MLE
SM-ML
SM-0
1.93
13.10
0.58
289.00
13.50
3.40
150.0
1.03
5.88
Dieldrin
eg/kg
MLE
SM-ML
SM-0
13.50
1.07
13.90
5.58
1.02
5.20
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
-------
TABLE 7-6. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation
Coefficient
of Variation (CV)
DDT, Composite-
eg/kg
HLE
SM-HL
SM-0
SM-COM
154.00
1.24
65.30
162.00
12.30
68.10
1.05
9.97
1.04
DDT, Composite*
i«g/kg
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
18.60
7.22
154.00
1.24
65.30
31.10
43.90
162.00
12.30
68.10
1.67
6.08
1.05
9.97
1.04
4,4'-DDD
tig/kg
MLE
SM-ML
SM-0
64.10
0.07
67.70
5.06
1.06
77.40
4,4'-DDE
MLE
SM-ML
SM-0
64.50
0.67
67.70
9.17
1.05
13.70
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Mote: DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDE, and 4,4'-DDT.
-------
TABLE 7-6. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORNAL AND NONPARAHETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation
Coefficient
of Variation (CV)
.4'-DDT
MLE
SM-ML
SM-0
2.44
25.90
0.50
371.00
27.10
4.31
152.0
1.05
8.61
PCB, Composite-
MLE
SM-ML
SM-0
SM-COM
2,030.00
279.00
535.00
2,070.00
992.00
1,010.00
1.02
3.56
1.89
PCB, Composite''
ng/kg
19
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
889.00
1,300.00
2,030.00
279.00
535.00
2,400.00
155,000.00
2,070.00
992.00
1,010.00
2.70
120.0
1.02
3.56
1.89
PCB-1016
pg/kg
MLE
SM-ML
SM-0
256.00
0.00
270.00
0.00
1.06
0.00
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SH-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-6. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGHORNAL AND NONPARANETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
-J
I
oo
Pollutant
PCB-1221
PCB-1232
PCS -1242
PCB-1248
PCB-1254
PCB-1260
Percent Estimation
Unit Detect Procedure*
iig/kg 0 HLE
SM-ML
SM-0
i>g/kg 0 HLE
SM-ML
SM-0
M9/kg 0 MLE
SM-ML
SM-0
ng/kg 9 MLE
SM-ML
SM-0
(•g/kg 9 MLE
SM-ML
SM-0
tig/kg 10 HLE
SM-HL
SM-0
Mean
256! 00
0.00
256.00
0.00
256!00
0.00
75.10
277.00
32.50
26,500.00
427.00
184.00
115.00
307.00
62.30
Standard
Deviation
270 ! 00
0.00
270.00
0.00
270.00
0.00
965.00
310.00
187.00
2490000000
747.00
744.00
1,710.00
371.00
287.00
Coefficient
of Variation (CV)
l!o6
0.00
1.06
0.00
l!o6
0.00
12.80
1.12
5.75
94000
1.75
4.04
14.90
1.21
4.61
MLE = Weighted Functions of Stratum Multiple Censor Point HLEs. Lognormality Assumed.
SH-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
= Honestimable.
-------
TABLE 7-7.
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORNAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
PERCENT SOLIDS, PHOSPHORUS, AND TOTAL KJELDAHL NITROGEN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation
Coefficient
of Variation (CV)
Percent Solids
100
HUE
SM-ML
SH-0
30.80
21.00
21.00
126.00
24.60
24.60
4.11
1.17
1.17
Phosphorus
mg/kg
100
MLE
SM-ML
SH-0
7,120.00
4,480.00
4,480.00
43,100.00
9,960.00
9,960.00
6.06
2.22
2.22
Total Kjeldahl Nitrogen
mg/kg
100
MLE
SM-ML
SM-0
50,100.00
42,400.00
42,400.00
62,800.00
24,700.00
24,700.00
1.25
0.58
0.58
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
-------
Final Report
November 11, 1992
CHAP7. TSD
Of the 19 individual pollutants for which national pollutant-concentration estimates were produced from
the NSSS data using the maximum-likelihood method, pollutants with higher detection rates tended to
have the smaller coefficients of variation. One pollutant, PCB-1254, had an unrealistic estimate.
Although this pollutant was detected above the minimum level about 9% of the time, it was detected at
concentrations about 10 times higher than the minimum-level values in each stratum. This resulted in
large MLEs of strata variances that are used to produce estimates of both the expected value of the
pollutant concentration E(X) and the variance of the pollutant concentration V(X). Review of the raw
data strongly suggests that, in the case of PCB-1254, the assumption that pollutant concentration is
distributed lognormally is not applicable.
Estimates of the mean pollutant concentration produced using the assumption of lognormality generally
were found to be lower than estimates generated when the minimum level was substituted for censored
data. On the other hand, the mean pollutant concentration estimated under the assumption of
lognormality was higher than estimates produced when no pollutant was assumed to be present in samples
from which the pollutant was not detected above the minimum level. The exceptions to this are bis(2-
ethylhexyl) phthalate, copper, PCB-1254, and zinc.
Tables 7-8, 7-9, and 7-10 present 95% confidence intervals about the estimated national pollutant-
concentration means resulting from each estimation method. These estimates are provided in response to
public request. A negative lower confidence limit indicates that the value zero is statistically credible for
the true mean pollutant concentration. Estimates of the standard deviation of the mean of pollutant
concentrations for a given pollutant reported in Tables 7-8, 7-9, and 7-10 were generated as the square
root of the estimated variance of the distribution of concentration means for that pollutant. The formula
used to generate the variance of the estimated mean pollutant concentrations is that presented by William
G. Cochran in of his book entitled, Sampling Techniques (Chapter 5A.14). Notice that the reported
standard deviations of the mean estimates reported in Tables 7-8, 7-9, and 7-10 are much smaller than
those shown in Tables 7-5, 7-6, and 7-7, respectively. That is because the standard deviations reported
in Tables 7-5, 7-6, and 7-7 estimate the standard deviation across the distribution of a pollutant's
concentrations. The standard deviations reported in Tables 7-8, 7-9, and 7-10, on the other hand,
estimate the standard distribution across the distribution of a pollutant's mean concentrations.
7.4.3 Lognormal and Nonparametric Pollutant-Concentration Percentile Estimates
Three sets of national concentration percentiles for the pollutants of concern are presented in this section.
The first set of estimates were generated assuming that pollutant concentrations follow a lognormal
distribution. Multicensored maximum-likelihood statistical techniques discussed in section 7.4.1 were used
to produce estimates under this assumption. The remaining two sets of nonparametric estimates made no
assumption about the parametric distribution of pollutant concentrations. The two nonparamteric estimates
differed with respect to assumptions made concerning censored pollutant-concentration data. For one set
of nonparametric estimates, censored data were assumed to be present at the minimum level of
quantitation. For the other set of nonparametric estimates, a pollutant was considered to be absent, as
denoted by a concentration value of zero, for censored samples. For all three assumptions, estimates of
the median (50th percentile), 90th, 95th, 98*, and 99th percentile concentrations are reported for each
pollutant.
7-40
-------
TABLE 7-8.
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAHETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation of
Mean Estimate
Lower 95X
Conf. Limit
Upper 95X
Conf. Limit
Aldrin/Dieldrirr
M9/kg
MLE
SM-ML
SM-0
SH-COM
26.70
1.65
14.40
3.04
0.69
1.61
20.70
0.30
11.30
32.60
3.00
17.60
Aldrin/Dieldrin*
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
6.03
6.63
26.70
1.65
14.40
2.63
82.50
3.04
0.69
1.61
0.87
-155.14
20.70
0.30
11.30
11.20
168.00
32.60
3.00
17.60
Arsenic
mg/kg
80
MLE
SM-ML
SM-0
9.52
10.30
8.66
2.03
1.55
1.59
5.53
7.26
5.53
13.50
13.30
11.80
Benzene
MLE
SM-ML
SM-0
956.00
0.08
189.00
0.03
587.00
0.03
1,330.00
0.12
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level- Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Note: Aldrin/Dieldrin is a combination of Aldrin and Oieldrin.
-------
TABLE 7-8. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORHAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
POLLUTANTS OF CONCERN
Pollutant Unit
Benzo(A)pyrene M9/kg
Beryllium mg/kg
Bis(2-Ethylhexyl) Phthalate jig/kg
Cadmium mg/kg
Cadmiunr mg/kg
Chlordane i«g/kg
Percent Estimation
Detect Procedure*
3 MLE
SM-ML
SM-0
22 MLE
SM-HL
SM-0
63 MLE
SM-ML
SM-0
69 MLE
SM-ML
SM-0
69 MLE
SM-ML
SM-0
0 MLE
SM-ML
SM-0
Mean
9,620.00
76.90
0.38
1.85
0.12
73,600.00
54,000.00
48,600.00
8.74
39.40
36.00
7.18
10.30
6.96
321 !00
1.76
Standard
Deviation of
Mean Estimate
1,270.00
31.40
0.04
0.26
0.03
46,400.00
10,300.00
10,500.00
1.28
28.50
28.50
0.78
1.37
1.32
38.20
1.71
Lower 95%
Conf. Limit
7,120.00
15.30
0.30
1.34
0.07
-17,418.38
33,800.00
28,100.00
6.22
-16.37
-19.75
5.65
7.65
4.37
246.00
-1.58
Upper 95X
Conf. Limit
12,100.00
138.00
0.46
2.37
0.17
165,000.00
74,100.00
69,100.00
11.20
95.20
91.80
8.71
13.00
9.55
396^00
5.10
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
Estimates Generated After Deleting an Extreme Outlier Observation from Stratum 3.
= Nonestimable.
-------
TABLE 7-8. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORNAL AND HONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation of
Mean Estimate
Lower 9SX
Conf. Limit
Upper 95X
Conf. Limit
Chromium
mg/kg
91
MLE
SM-ML
SM-0
124.00
163.00
160.00
34.10
44.00
44.10
57.20
76.80
73.90
191.00
249.00
247.00
Copper
mg/kg
100
MLE
SM-ML
SM-0
724.00
657.00
657.00
110.00
65.20
65.20
509.00
529.00
529.00
940.00
784.00
784.00
DDT, Composite*
i«g/kg
MLE
SM-ML
SM-0
SM-COM
154.00
1.24
65.30
18.30
0.59
7.63
119.00
0.08
50.30
190.00
2.39
80.20
DDT, Composite'
eg/kg
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
18.60
7.22
154.00
1.24
65.30
2.74
2.28
18.30
0.59
7.63
13.30
2.75
119.00
0.08
50.30
24.00
11.70
190.00
2.39
80.20
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 x Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Note: DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDD, and 4,4'-DDT.
-------
TABLE 7-8. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAHETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
POLLUTANTS OF CONCERN
Pollutant
Heptachlor
Hexachlorobenzene
Hexachlorobutadiene
Lead
Lindane ( Gamma -BHC)
Mercury
Molybdenum
Percent Estimation
Unit Detect Procedure*
iig/kg 0 MLE
SM-ML
SM-0
eg/kg 0 MLE
SM-ML
SM-0
tig/kg 0 MLE
SM-ML
SM-0
mg/kg 80 MLE
SM-ML
SM-0
Mg/kg 0 MLE
SM-ML
SM-0
mg/kg 64 MLE
SM-ML
SM-0
mg/kg 53 MLE
SM-ML
SM-0
Mean
25.60
0.02
9.56oloQ
0.00
9,560.00
0.00
131.00
135.00
109.00
32! 20
0.16
5.30
6.58
3.83
9.63
14.70
6.66
Standard
Deviation of
Mean Estimate
3^06
0.01
1,270.00
0.00
1,270.00
0.00
19.70
11.50
12.20
3.82
0.13
2.03
1.04
1.04
2.03
1.54
1.25
Lower 95X
Conf. Limit
19.60
-0.01
7,060.00
0.00
7,060.00
0.00
92.80
112.00
84.70
24! 80
-0.10
1.31
4.54
1.79
5.64
11.70
4.20
Upper 95X
Conf. Limit
31.60
0.04
12,100'.00
0.00
12,100.00
0.00
170.00
158,00
132.00
39.70
0.42
9.28
8.63
5.88
13.60
17.70
9.12
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
= Nonestimable.
-------
TABLE 7-8. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAHETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Petect
Estimation
Procedure*
Mean
Standard
Deviation of
Mean Estimate
Lower 95X
Conf. Limit
Upper 9SX
Conf. Limit
N-Nitrosodimethylamine
eg/kg
MLE
SM-ML
SH-0
47,800.00
0.00
6,370.00
0.00
35,300.00
0.00
60,300.00
0.00
Nickel
mg/kg
67
MLE
SM-ML
SM-0
46.00
58.20
44.00
12.30
10.10
10.50
21.80
38.30
23.50
70.10
78.10
64.50
PCB, Composite*
pg/kg
MLE
SM-ML
SM-0
SM-COM
2,030.00
279.00
535.00
238.00
121.00
123.00
1,570.00
40.90
293.00
2,500.00
517.00
777.00
PCB, Composite*
pg/kg
19
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
889.00
1,300.00
2,030.00
279.00
535.00
299.00
19,500.00
238.00
121.00
123.00
304.00
-36,926.19
1,570.00
40.90
293.00
1,470.00
39,500.00
2,500.00
517.00
777.00
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonest finable.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-8. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAHETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation of
Mean Estimate
Loner 95%
Conf. Limit
Upper 95X
Conf. Limit
Selenium
mg/kg
68
MLE
SM-ML
SM-0
5.58
7.70
4.28
0.89
1.26
0.87
3.83
5.24
2.57
7.33
10.20
5.99
Toxaphene
i>9/kg
MLE
SM-ML
SM-0
1,280.00
0.00
153.00
0.00
980.00
0.00
1,580.00
0.00
Trichloroethene
M9/kg
MLE
SM-ML
SM-0
968.00
17.10
189.00
12.20
599.00
-6.74
1,340.00
41.00
Zinc
mg/kg
100
MLE
SM-ML
SM-0
1,220.00
1,430=00
1,430.00
151.00
281.00
281.00
925.00
877.00
877.00
1,520.00
1,980.00
1,980.00
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
= Nonestimable.
-------
TABLE 7-9.
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARANETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation of
Mean Estimate
Lower 9SX
Conf. Limit
Upper 95X
Conf. Limit
-j
•t
-j
Aldrin/Dieldrinr
Aldrin/Dieldrin*
Aldrin
Dieldrin
i«g/kg
eg/kg
MLE
SH-ML
SM-0
SM-COM
MLE-ML
MLE-COM
SH-ML
SM-0
SM-COM
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
26.70
1.65
14.40
6.03
6.63
26.70
1.65
14.40
1.93
13.10
0.58
13.50
1.07
3.04
0.69
1.61
2.63
82.50
3.04
0.69
1.61
8.98
1.53
0.33
1.56
0.62
20.70
0.30
11.30
0.87
-155.14
20.70
0.30
11.30
-15.67
10.10
-0.07
10.50
-0.14
32.60
3.00
17.60
11.19
168.00
32.60
3.00
17.60
19.50
16.10
1.23
16.60
2.28
* MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 * Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
• Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
* Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
. = Nonestimable.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
-------
TABLE 7-9. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEUAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation of
Mean Estimate
Lower 95X
Conf. Limit
Upper 95X
Conf. Limit
~0
I
00
DDT, Composite1
DDT, Composite"
4,4'-DDD
4,4'-DDE
MLE
SM-ML
SM-0
SH-COM
HLE-ML
MLE-COM
SM-ML
SM-0
SH-COM
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
154.00
1.24
65.30
18.60
7.22
154.00
1.24
65.30
64.10
0.06
64.50
0.67
18.30
0.59
7.63
2.74
2.28
18.30
0.59
7.63
7.64
0.04
7.65
0.51
119.00
0.08
50.30
13.30
2.75
119.00
0.08
50.30
49.10
-0.00
49.50
-0.33
190.00
2.39
80.20
24.00
11.70
190.00
2.39
80.20
79.10
0.13
79.50
1.68
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Note: DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDE, and 4,4'-DDT.
-------
TABLE 7-9. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARANETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation of
Mean Estimate
Lower 9SX
Conf. Limit
Upper 95X
Conf. Limit
4,4'-DDT
PCB, Composite*
PCB, Compos iteb
PCB-1016
eg/kg
i>9/kg
us/kg
Vg/kg
19
NLE
SH-ML
SM-0
MLE
SM-ML
SM-0
SM-COM
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
MLE
SM-ML
SM-0
2.44
25.90
0.50
2,030.00
279.00
535.00
889.00
1,300.00
2,030.00
279.00
535.00
256.00
0.00
8.92
3.05
0.29
238.00
121.00
123.00
299.00
19,500.00
238.00
121.00
123.00
30.60
0.00
-15.04
19.90
-0.06
1,570.00
40.90
293.00
304.00
-36,926.19
1,570.00
40.90
293.00
196.00
0.00
19.90
31.80
1.07
2,500.00
517.00
777.00
1,470.00
39,500.00
2,500.00
517.00
777.00
316.00
0.00
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML * Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-9. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAHETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
PCB-1221
PCB-1232
PCB-1242
PCB-1248
PCB-1254
PCS -1260
Percent Estimation
Unit Detect Procedure*
ng/kg 0 MLE
SM-ML
SM-0
Mg/kg 0 MLE
SM-ML
SM-0
i»g/kg 0 MLE
SM-ML
SM-0
ng/kg 9 MLE
SM-ML
SM-0
ng/kg 9 MLE
SM-ML
SM-0
Mg/kg 10 MLE
SM-ML
SM-0
Mean
256.00
0.00
256^00
0.00
256.00
0.00
75.10
277.00
32.50
26,500.00
427.00
184.00
115.00
307.00
62.30
Standard
Deviation of
Mean Estimate
30.60
0.00
30.60
0.00
30.60
0.00
37.50
31.00
10.10
313,000,000.00
91.60
92.10
209.00
43.80
35.10
Lower 95X
Conf. Limit
196.00
0.00
196.00
0.00
196.00
0.00
1.56
216.00
12.80
-613,340,972.58
247.00
3.48
-296.03
221.00
-6.42
Upper 95X
Conf. Limit
0.00
316.00
0.00
316.00
0.00
149.00
338.00
52.30
613,000,000.00
606.00
365.00
525.00
393.00
131.00
* MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparemetric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
= Nonestimable.
-------
TABLE 7-10.
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORNAL AND NONPARANETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
STANDARD DEVIATION AND CONFIDENCE INTERVAL FOR THE MEAN
PERCENT SOLIDS, PHOSPHORUS. AND TOTAL KJELDAHL NITROGEN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Mean
Standard
Deviation of
Mean Estimate
Lower 9SX
Conf. Limit
Upper 95X
Conf. Limit
Percent Solids
100
NLE
SH-ML
SM-0
30.80
21.00
21.00
15.00
2.74
2.74
1.39
15.60
15.60
60.20
26.40
26.40
Phosphorus
mg/kg
100
HUE
SH-ML
SM-0
7,120.00
4,480.00
4,480.00
5,270.00
1,220.00
1,220.00
-3,205.14
2,080.00
2,080.00
17,400.00
6,870.00
6,870.00
Total Kjeldahl Nitrogen
mg/kg
100
HUE
SM-ML
SM-0
50,100.00
42,400.00
42,400.00
6,380.00
2,710.00
2,710.00
37,600.00
37,000.00
37,000.00
62,600.00
47,700.00
47,700.00
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
-------
Final Report
November 11, 1992
CHAP7.TSD
If the variable X denotes pollutant concentration, the p* percentile pollutant concentration is defined as
the smallest value of X such that the cumulative distribution function of X , denoted as F(X), is greater
than or equal to p. That is,
p"1 percentile = Xp where X,, is the smallest value of X such that F(Xp) ^ p ie., F '(p) = X,,.
Percentile estimates produced under the assumption that pollutant concentrations follow a lognormal
distribution were generated using the maximum-likelihood technique. A pollutant's p* percentile
concentration is estimated under the assumption that the pollutant follows a lognormal distribution as
follows:
X =exp(p+Z,*8)
where Zp is the largest z score from the standard normal distribution such that F(zp) < p and the
estimates n and a are the estimates of the mean and standard deviation, respectively, for the national
distribution of the pollutant's concentrations under the assumption of lognormality. The estimated values
of \i and a are determined from national estimates of the pollutant-concentration mean E(X) and the
squared value of the estimated coefficient of variation (CV.)
For the percentiles reported in this section, the value of the Z score for the median is zero, while 7^M
= 1.282, Zo95 = 1.645, and Z^ = 2.055. With the appropriate Z score value, other percentile points
may be calculated using the same method described in this section.
Pollutant concentration is distributed lognormally if the natural logarithm transformation of X (In X) is
distributed normally with mean /i and variance a2 (ie., lx(X) ~ N^o2). Under these conditions, the
mean (E(X)), the variance (V(X)), and the p01 percentile are estimated as follows:
E(X) = exp(fi + -~d2)
V(X) = exp(2p+d2) (exp(82-l)
p^percentile = exp(p+Z d)
7-52
-------
Final Report
November 11, 1992
CHAP7.TSD
Additionally, when X is distributed lognormally, the coefficient of variation (CV) is estimated as
CV(X) =[exp(82-l)]1/2.
In order to estimate the p* percentile, national estimates of n and a are needed. The national estimate
of a2 for a given pollutant was obtained by equating the squared value of the estimated pollutant-
concentration coefficient of variation (CV) to the lognormal expression for the squared coefficient of
variation and solving for er2, as noted below.
CV2 = exp(oz)-l - d2
Likewise, the estimate of /* was obtained for a pollutant by equating the estimated national pollutant-
concentration mean to the lognormal expression of the mean and solving for /i.
X = expU+lo2) - A = InUJ-ld2.
Because the NSSS was conducted as a stratified survey, national pollutant-concentration means (E(X)),
and variances (V(X)), were estimated as weighted combinations of stratum estimates. Monte Carlo
simulations to assess the appropriateness of this assumption are presented in Chapter 10.
Two sets of nonparametric estimates of pollutant concentrations were generated using substitution
methods. Nonparametric estimates do not require any assumptions about the distribution of pollutant
concentration. Assumptions for nonparametric estimates in these analyses regard the concentration of
censored pollutant-concentration data. For the first set of nonparametric estimates, if a pollutant
concentration was not measured above the minimum level (i.e., the value is censored) then it was
assumed that the pollutant concentration occurred at the minimum level. For the second set of estimates,
it was assumed that the pollutant was absent if it was not detected above the minimum level.
7-53
-------
Final Report
November 11, 1992
CHAP7. TSD
Nonparametric national pollutant concentration p"1 percentile estimate (Xp) were generated as a weighted
combination of nonparametric stratum estimates. The equation for estimating the national p* percentile
concentration is given below.
4
Xp = F(X) :>p where F(X) = ]T wiFi(X}
where
and I(X;j < x) =1 if Xs < x for x > 0
= 0 otherwise.
Estimates of the median, 90th, 95th, 98th, and 99th percentile for the pollutants of concern are presented
in Tables 7-11, 7-12, and 7-13. For a given pollutant, the first estimate presented is designated as
"MLE." This indicates that the estimate was generated under the assumption that pollutant concentration
follows a lognormal distribution. The other two estimates are the nonparametric estimates. Estimates
recorded in the rows "SM-ML" indicate that the minimum level was substituted for censored pollutant
concentration values. The estimates in rows designated "SM-0" were produced assuming that the pollutant
was absent if it was not measured above the minimum level.
Also recorded in these tables are the national estimate of percent detection. This estimate was determined
as a weighted linear combination of the four stratum estimates of percent detection. Ten of the pollutants,
including the composite PCBs and DDTs, are not detected at all in the NSSS. For these pollutants,
"MLE" estimates are not available because all of the data were censored. Additionally, MLE percentile
estimates are not available for benzo(a)pyrene, dieldrin, and trichloroethene. This is because the pollutant
was not detected in sewage sludge from any of the POTWS sampled from one or more of the flow rate
strata. Thus, the national estimate was considered nonestimable.
7-54
-------
TABLE 7-11.
NATIONAL POLLUTANT CONCENTRATION PERCENTILE ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Median
90th
Percentile
95th
Percentile
98th
Percentile
99th
Percentilt
-J
Ui
Aldrin/Dieldrin'
Aldrin/Dieldrin11
Arsenic
Benzene
Benzo(A)pyrene
Mg/kg
rag/kg
MgAg
Mg/kg
80
MLE
SM-ML
SM-0
SM-COM
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
20.30
0.00
10.30
1.43
0.01
20.30
0.00
10.30
67
80
4.38
357.00
0.00
,700.00
0.00
41.70
0.00
23.30
12.60
1.21
41.70
0.00
23.30
21.50
21.10
19.50
2,080.00
0.00
28,600.00
0.00
48.60
13.80
40.90
23.30
4.37
48.60
13.80
40.90
33.30
41.30
41.30
3,130.00
0.00
32,900.00
0.00
108.00
24.40
56.80
46.70
18.50
108.00
24.40
56.80
54.30
61.50
60.40
5,020.00
0.00
42,800.00
750.00
149.00
30.40
75.40
74.00
48.20
149.00
30.40
75.40
75.00
61.60
61.60
7,040.00
0.00
43,300.00
965.00
Beryllium
mg/kg
22
MLE
SM-ML
SM-0
0.27
0.90
0.00
0.79
5.00
0.50
1.07
8.00
0.60
1.52
8.34
0.98
1.92
8.56
1.13
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM <= Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
Nonestimable.
I
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
-------
TABLE 7-11. (Continued)
NATIONAL POLLUTANT CONCENTRATION PERCENTILE ESTIMATES FROM THE NATIONAL SEHAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
POLLUTANTS OF CONCERN
Percent Estimation
Pollutant Unit Detect Procedure*
Bis(2-Ethylhexyl) Phthalate Mg/kg 63 MLE
SM-ML
SM-0
Cadmium mg/kg 69 MLE
SM-ML
SM-0
Cadmium' mg/kg 69 MLE
SM-ML
SM-0
Chlordane Mg/kg 0 MLE
SM-ML
i
i SM-0
ON
Chromium mg/kg 91 MLE
SM-ML
SM-0
Copper mg./kg 100 MLE
SM-ML
SM-0
DDT, Composite1 Mg/kg 0 MLE
SM-ML
SM-0
SM-CCM
DDT, Composite" Mg/kg 3 MLE
MLE
SM-ML
SM-0
SM-COM
Median
11,400
17,000
5,020
3
6
3
3
6
3
241
0
43
40
38
451
466
466
118
0,
49.
9.
1.
118.
0.
49.
.00
.00
.00
.25
.50
.60
.52
.50
.60
.00
.00
.90
.10
. 10
.00
.00
.00
.00
.00
.30
57
17
00
00
30
90th
Percentile
135,000
131,000
131,000
19
19
9
16
19
9
505
0
278
273
273
1,570
1,200
1,200
241
0.
103.
41.
13.
241.
0.
103.
.00
.00
.00
.70
.90
.39
.20
.00
.35
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
90
50
00
00
00
95th
Percentile
273,000.
191,000.
191,000.
32
21
17
25
21
16
568
0
470
930
930
2,240
1,940
1,940
274,
0.
135.
63.
27.
274.
0.
135.
.00
.00
.00
.80
.50
.00
.10
.30
.70
.00
.00
.00
.00
.00
.00
,00
.00
.00
.00
,00
90
00
00
00
00
98th
Percentile
603,000
426,000
426,000
58
41
25
40
25
24
1,360
0
848
1,980
1,980
3,330
2,400
2.400
651
12
273
102.
59.
651.
12.
273.
.00
.00
.00
.40
.70
.30
.90
.30
.40
.00
.00
.00
.00
.00
.00
.00
.00
.00
.30
.00
,00
,00
,00
,30
00
99th
Percentile
1,020,000.
516,000.
516,000
85
153
153
56
87
87
1,860
0
1,250
2,040
2,040
4,330
2,970
2,970
893.
27.
374.
140.
98.
893.
27.
374.
.00
.00
.00
.50
.00
.00
.50
.70
.70
.00
.00
.00
.00
.00
.00
.00
.00
.00
.90
.00
00
90
00
,90
00
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
I
Estimates Generated After Deleting an Extreme Outlier Observation from Stratum 3.
= Nonestimable.
-------
TABLE 7-11. (Continued)
RATIONAL POLLUTANT CONCENTRATION PEDCENTILE ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGRORMAL AND NONFARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
POLLUTANTS OF CONCERN
Percent Estimation
Pollutant Unit Detect Procedure*
Heptachlor Mg/kg 0 MLE
SM-ML
SM-0
Hexachlorobenzene Mg/kg 0 MLE
SM-ML
SM-0
Hexachlorobutadiene Mg/kg 0 MLE
SM-ML
SM-0
Lead mg/kg 80 MLE
SM-ML
^j SM-0
Lindane (Gamma-BHC) Mg/kg 0 MLE
SM-ML
SM-0
Mercury mg/kg 64 MLE
SM-ML
SM-0
Median
19,
0,
4,570,
0
4,570,
0
77
106
75
24
0
1.
4.
1.
.50
.00
.00
.00
.00
.00
.70
.00
.90
.40
.00
.64
.30
70
90th
Percentile
39.
0.
28,600.
0.
28,600.
0.
289,
236.
236,
52
0.
11.
12.
6.
90
00
00
00
.00
,00
,00
,00
.00
.00
.00
60
80
39
95th
Percent i le
45,
0.
32.900,
0.
32.900,
0,
419
375
310
57
0
20
16
8
,70
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.40
.80
.54
98th
Percentile
109.
0.
42,800
0
42,800
0
639
530
528
136
0
38
42
40
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.10
.80
.20
99th
Percentile
149.
0,
43,300,
0.
43,300,
0,
843
541
541
186
0
57.
44,
44.
.00
,00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.80
.80
.80
* MLE « Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormallty Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognorroality Assumed. Maximum Hondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 » Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
• Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
* Composite Pollutant Considered a Detect if at Least ,One Individual Pollutant is Measured Above the Minimum Level.
I
«• Nonestimable.
Note: DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDE, and 4,4'-DDT.
-------
TABLE 7-11. (Continued)
NATIONAL POLLUTANT CONCENTRATION FERCENTILE ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGHORMAL AND NONPARAMETRIC SUBSTITUTION METBOD ESTIMATION PROCEDURES
POLLUTANTS OF CONCERN
Percent Estimation
Pollutant Unit Detect Procedure*
Molybdenum mg/kg 53 MLE
SM-ML
SM-0
N-Nitrosodimethylamine eg/kg 0 MLE
SM-ML
SM-0
Nickel mg/kg , 67 MLE
SM-ML
SM-0
PCB, Composite" (ig/kg 0 MLE
SM-ML
T3 SM-0
^3 SM-COM
PCB, Composite* t>g/kg 19 MLE
MLE
SM-ML
SM-0
SM-COM
Selenium mg/kg 68 MLE
SM-ML
SM-0
Toxaphene Mg/kg 0 MLE
SM-ML
SM-0
Median
4.
11.
2.
22,800
0
18
29
14.
1,480.
0
220
309.
10.
1,480.
0.
220.
3.
4.
3.
962.
0.
.72
.20
.26
.00
.00
.70
.20
.60
.00
.00
.00
.00
.80
00
00
00
23
80
50
00
00
90th
Percentile
21
34.
14.
143,000
0
104
110
107
3.050
681
1,250
1,990
568
3,050
681
1,250
12.
12.
6.
2,000.
0.
.80
.80
.10
.00
.00
.00
.00
.00
.00
.00
.00
.00
00
.00
.00
. uu
.30
.50
80
00
00
95th
Percentile
33.
42.
29
164,000
0
170
209
180
5,430
1,320
1,700
3,380
1,760
5,430
1,320
1,700
18
26
9.
2,270.
0.
.70
.50
.40
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.43
.00
00
98th
Percent
54.
56.
55.
214,000
0
294
438
438
8,270
2,510
2,860
6,130
6,240
8.270
2,510
2,860
27
50
28.
5,420.
0.
ile
.90
.40
.30
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.70
.40
.60
.00
.00
99th
Percentile
75.
59.
58
217,000
0
423
460
460
10,070
5,870
6,050
9,100
14,400
10.700
5,870
6,050
36,
56.
41.
7,440.
0.
.90
.40
.30
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.00
.80
.30
.40
00
.00
MLE - Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 - Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
= Nonestimable.
-------
TABLE 7-11. (Continued)
NATIONAL POLLUTANT CONCENTRATION PERCENTILE ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Median
90th
Percentile
95th
Percentile
98th
Pereentile
99th
Percentile
Trichloroethene
CS/kg
MLE
SM-ML
SM-0
357.00
0.00
2.080.00
0.00
3,130.00
0.00
5.020.00
0.00
7,040.00
41.20
Zinc
mg/kg
100
MLE
SM-ML
SM-0
746.00
706.00
706.00
2,660.00
2,370.00
2,370.00
3,820.00
4.120.00
4,120.00
5,730.00
4,790.00
4,790.00
7,500.00
5,990.00
5,990.00
Ul
MLE » Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
= Nonestimable.
-------
TABLE 7-12.
HATIOHAL FOLLUTAHT CONCENTRATION PERCENTILE ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGHORMAL AHD NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure"
Median
90th
Percentile
95th
Percentile
98th
Percentile
99th
Fercentile
Aldrin/Dieldrin1
fg/kg
MLE
SM-ML
SM-0
SM-COM
20.30
0.00
10.30
41.70
0.00
23.30
48.60
13.80
40.90
108.00
24.40
56.80
149.00
30.40
75.40
Aldrin/Dieldrinfc
Mg/kg
MLE
MLE-COM
SM-ML
SM-0
SM-COM
0.01
20.30
0.00
10.30
1.21
41.70
0.00
23.30
4.37
48.60
13.80
40.90
18.50
108.00
24. 40
56.80
48.20
149.00
30.40
75.40
A^drin
O\
O
Mg/kg
MLE
SM-ML
SM-0
0.01
10.00
0.00
0.74
20.80
0.00
2.35
24.00
0.00
8.61
57.50
17.20
20.30
87.00
18.50
Dieldrin
Mg/kg
MLE
SM-ML
SM-0
10.20
0.00
20.80
0.00
33.40
0.00
57.50
24.60
87.00
33.20
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
-------
TABLE 7-12. (Continued)
RATIONAL POLLUTANT CONCENTRATION PERCENT ILE ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONFARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Median
90th
Percentile
95th
Percentile
98th
Percentile
99th
Percentili
DDT. Composited)
Mg/kg
MLE
SM-ML
SM-0
SM-COM
118.00
0.00
49.30
241.00
0.00
103.00
274.00
0.00
135.00
651.11
12.30
273.00
893.00
12.30
374.00
DDT, Composite(2)*
Mg/kg
MLE-ML
MLE-COM
SM-ML
SM-0
SM-COM
9.57
1.17
118.00
0.00
49.30
41.90
13.50
241.00
0.00
103.00
63.90
27.00
274.00
0.00
135.00
102.00
59.00
651.00
12.30
273.00
140.00
98.90
893.00
27.90
374.00
4,4'-DDD
Mg/kg
MLE
SM-ML
SM-0
48.10
0.00
100.00
0.00
114.00
0.00
395.00
0.00
419.00
0.00
'-DDE
4,4'-DDT
eg/kg
Mg/kg
MLE
SM-ML
SM-0
MLE
SM-ML
SM-0
49.20
0.00
0.02
19.70
0.00
102.00
0.00
0.93
41.50
0.00
123.00
0.00
2.94
46.30
0.00
271.00
0.00
10.80
126.00
8.39
372.00
0.00
25.50
155.00
13.20
PCB, Composite'
Mg/kg
MLE
SM-ML
SM-0
SM-COM
1,480.00
0.00
220.00
3,050.00
681.00
1,250.00
5,430.00
1,320.00
1,700.00
8,270.00
2,510.00
2,860.00
10,700.00
5,870.00
6,050.00
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable.
Note: DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDE, and 4,4'-DDT.
-------
TABLE 7-12. (Continued)
RATIONAL POLLUTANT CONCENTRATION FERCENTILE ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
Unit
Percent
Detect
Estimation
Procedure*
Median
90th
Percentile
95th
Percentile
98th
Percentile
99th
Percentile
PCB, Composite11
Mg/kg
MLE
MLE-COM
SM-ML
SM-0
SM-COM
10.80
1,480.00
0.00
220.00
568.00
3,050.00
681.00
1,250.00
1,760.00
5,430.00
1.320.00
1,700.00
6,240.00
8,270.00
2,510.00
2,860.00
14,400.00
10,700.00
5,870.00
6,050.00
PCB-1016
Mg/kg
MLE
SM-ML
SM-0
192.00
0.00
401.00
0.00
454.00
0.00
1,080.00
0.00
1,490.00
0.00
PCB-1221
Mg/kg
MLE
SM-ML
SM-0
192.00
0.00
401.00
0.00
454.00
0.00
1,080.00
0.00
1,490.00
0.00
-1232
f>g/kg
MLE
SM-ML
SM-0
192.00
0.00
401.00
0.00
454.00
0.00
1,080.00
0.00
1,490.00
0.00
FCB-1242
Mg/kg
MLE
SM-ML
SM-0
192.00
0.00
401.00
0.00
454.00
0.00
1,080.00
0.00
1,490.00
0.00
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs . Lognorraality Assumed.
MLE-ML = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Nondetects Set Equal to the Minimum Level.
MLE-COM = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed. Maximum Nondetect Set Equal to the Highest Minimum
Level; Other Nondetects Set Equal to Zero.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetacts Set Equal to Zero.
SM-COM = Weighted Nonparametric Substitution Method Stratum Estimates. Maximum Nondetect Set Equal to the Highest Minimum Level; Other
Nondetects Set Equal to Zero.
Composite Pollutant Considered a Detect if All Individual Pollutants are Measured Above the Minimum Level.
Composite Pollutant Considered a Detect if at Least One Individual Pollutant is Measured Above the Minimum Level.
= Nonestimable ,
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB- 1254 , and PCB-1260.
-------
TABLE 7-12. (Continued)
NATIONAL POLLUTANT CONCENTRATION FERCEHTILE ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USING LOGNORMAL AND NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
Percent
Unit Detect
Estimation
Procedure*
Median
90th
Percentile
95th
Percentile
98th
Percentile
99th
Percentile
PCB-1248
Mg/kg
MLE
SM-ML
SM-0
5.83
209.00
0.00
105.00
428.00
0.00
240.00
673.00
231.00
607.00
1.510.00
354.00
1,120.00
1,660.00
598.00
PCB-1254
Mg/kg
MLE
SM-ML
SM-0
0.28
209.00
0.00
129.00
859.00
0.00
740.00
1.580.00
1,250.00
5,260.00
2,530.00
2,460.00
19.200.00
3,580.00
3,530.00
PCB-1260
Mg/kg
10
MLE
SM-ML
SM-0
7.68
209.00
0.00
151.00
462.00
0.00
352.00
828.00
493.00
913.00
1,910.00
654.00
1,710.00
2,110.00
1.350.00
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
Nonestimable.
-------
TABLE 7-13.
RATIONAL POLLUTANT CONCENTRATION PERCENTILE ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
USIHG LOGNORMAL AHD NONPARAMETRIC SUBSTITUTION METHOD ESTIMATION PROCEDURES
PERCENT SOLIDS. PHOSPHORUS, AND TOTAL KJELDAHL NITROGEN
Percent Estimation 90th 95th 98th 99th
Pollutant Unit Detect Procedure* Median Percentile Percentile Percentile Fercentile
r
Percent Solids X 100 MLE 7.28 64.00 119.00 239.00 378.00
SM-ML 10.70 63.20 71.10 87.00 96.90
SM-0 10.70 63.20 71.10 87.00 96.90
Phosphorus mg/kg 100 MLE 1,160.00 13,300.00 26,600.00 58,100.00 97,400.00
SM-ML 1,250.00 9,900.00 12,400.00 18,200.00 43,800.00
SM-0 1,250.00 9,900.00 12,400.00 18,200.00 43,800.00
Total Kjeldahl Nitrogen mg/kg 100 MLE 31,300.00 108,000.00 155,000.00 230,000.00 299,000.00
•jJ SM-ML 40,600.00 74,200.00 83,600.00 94,300.00 97,900.00
SM-0 40,600.00 74,200.00 83,600.00 94.300.00 97,900.00
MLE = Weighted Functions of Stratum Multiple Censor Point MLEs. Lognormality Assumed.
SM-ML •= Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to the Minimum Level.
SM-0 = Weighted Nonparametric Substitution Method Stratum Estimates. Nondetects Set Equal to Zero.
-------
Final Report
November 11, 1992
CHAP7.TSD
A percentile estimate, denoted as "SM-COM" is included for the composite estimates of aldrin/dieldrin
PCB and DDT. For the composite pollutant-concentration estimates, the maximum of all minimum-level
values for all compounds in a sample's composite was retained. The remaining minimum-level values for
the sample were set to zero. For a sample, these values then were summed across all compounds in the
composite to produce the data point that was used to estimate "SM-COM."
Graphical presentations of cumulative distribution functions estimated under the assumption of
lognormality and using the two nonparametric substitution procedures can be found in Figures 7-73
through 7-110, located at the end of this chapter. Plotted concentration values do not necessarily
represent observed data points. Rather, they represent incremental pollutant concentration values that
were chosen to span the full range of data for a pollutant. Therefore, plotted on the horizontal axis is
the probability that pollutant concentration in sewage sludge is at most the corresponding concentration
plotted on the vertical axis. That is,
fraction of POTffs less than concentration = Fx(c)
where X is the pollutant-concentration random variable and c is the pollutant concentration value plotted
on the vertical axis.
The estimated lognormal cumulative distribution functions used to determine the fraction of POTWs with
sewage sludge containing at most the concentration "c" of a pollutant assume that the concentration of
a pollutant follows a national lognormal distribution. That is, it was assumed that the cumulative
distribution function for a given pollutant could be expressed as
The nonparametric cumulative distributions were estimated for each substitution method as weighted
linear combinations of the stratum cumulative distribution functions. That is,
4
fraction of POTffs less than concentration = FY(c) = V* vf1Fv (c)
Xi
where
7-65
-------
Final Report
November 11, 1992
CHAP7.TSD
The cumulative distribution plots clearly illustrate how the estimation method influences conclusions. For
example, observe the cumulative distribution functions for beryllium in Figure 7-77. The national
detection rate for this metal was 22%. When the minimum level is substituted for observations that are
censored, the cumulative distribution defined by the triangle symbol indicates that approximately 53%
of secondary treatment POTWs would dispose of sewage sludge containing at most 1 milligram per
kilogram (mg/kg) of beryllium. On the other hand, the cumulative distribution function estimated under
the multicensored lognormal assumption suggests that 93% of the POTWs dispose of sewage sludge
containing at most 1 mg/kg of beryllium—this is determined from the plot defined by the symbol "x."
Finally, when it is assumed that samples contained no pollutant if the pollutant was not measured above
the minimum level, then the graph depicted by the symbol "o" suggests that 99% of secondary treatment
POTWs in the Nation dispose of sewage sludge that contains at most 1 mg/kg of beryllium.
7.5 DISTRIBUTIONAL ESTIMATES OF POLLUTANT CONCENTRATION BY AMOUNT OF
SEWAGE SLUDGE
National pollutant-concentration estimates, weighted by amount of sewage sludge disposed, are presented
in Tables 7-14, 7-15, and 7-16 (presented at the end of this chapter). For each pollutant, the national
mean pollutant concentration estimate is presented along with the standard deviation and 95% confidence
interval about the mean.
Two substitution methods were used for pollutant-concentration samples measured below the minimum
detection level. The first, SM-ML, sets the pollutant concentration for nondetects equal to the minimum
detection level. The second, SM-0, sets the pollutant concentration for nondetects to zero. For the
composite pollutants, a third substitution method is used, SM-COM. In this case, for each sample, the
highest minimum detection level among the nondetected samples is determined from the individual
pollutants. This value is substituted for the maximum nondetect, and the other nondetects are set equal
to zero. For example, suppose, for a given sample, DDT is measured at 15 /*g/kg, and ODD and DDE
are not measured above the respective detection limits of 5 ^tg/kg and 10 Mg/kg. The highest minimum
detection level among these nondetects is 10 //g/kg, for DDE. This value is retained and the
concentration for DDD is set equal to zero. Therefore, the values comprising the DDT composite
pollutant are 15, 0, and 10 Mg/kg. The DDT composite pollutant concentration for this sample would
then be 25 /xg/kg.
The dry weight of sewage sludge disposed by each POTW in 1988 was determined from the responses
in the NSSS questionnaire. For each POTW in the analytical survey, the dry weight disposed by each
disposal practice was summed together to produce a total dry weight of sewage sludge, in U.S. tons,
disposed by each POTW. The dry weights, by regulatory analytical use (RA) or disposal practice for
each POTW in the NSSS, are listed in Part A2 of the appendix. Because the quantity of sewage sludge
disposed in 1988, did not pass certain data integrity assessment criteria for 27 POTWs, the quantity of
sewage sludge disposed was imputed. These POTWs are identified in Chapter 9.
Estimates are presented for each of the applicable substitution methods. For some pollutants, the variance
under method SM-0 cannot be calculated because, within at least one stratum, there are no concentration
values above the minimum detection level. The resulting set of zero values precludes the calculation of
7-66
-------
Final Report
November 11, 1992
CHAP7.TSD
Pearson's product-moment estimate of correlation between the pollutant concentration and dry weight of
sewage sludge. These correlations are presented in Tables 7-17, 7-18, and 7-19 (presented at the end of
this chapter). A total of 291 tests of hypothesis were conducted. To control the Type I statistical error
rate to a level of a = 0.05 across all tasks, the null hypothesis of independence between pollutant
concentration and the mass of dry weight of sewage sludge disposed was rejected for individual tests if
the attained significance value (p-value) was 0.0001. Notice that the dry weight amount of sewage sludge
disposed and pollutant concentration were statistically correlated for chromium in stratum 3
(1 < FLOW^.10 MOD) for both substitution methods for those samples not quantified above the minimum
level. This number of statistically significant tests out of the 291 tests is insignificant.
For each of the pollutants of concern, each POTW has a single dry weight concentration value (Xy) and
a dry weight of sewage sludge disposed (Yjj). In order to weight the pollutant concentrations by the
amount of sewage sludge disposed, the concentration is multiplied by the sewage sludge dry weight to
produce a "concentration*dry weight" value (Zy) for each POTW.
The estimate of the weighted pollutant-concentration mean is a ratio estimator of the estimated national
"concentration*dry weight" mean over the estimated national sewage sludge dry weight mean. The
formula for the estimated mean (R) is
£**•>
i^i
where
X}j = dry weight pollutant concentration from the j^1 POTW in stratum i
Y1:j = dry weight of sewage sludge disposed in 1988 by the j"1 POTW in stratum i
Yd = mean dry weight of sewage sludge disposed in 1988 in stratum i
Z± - mean concentration*dry weight in stratum i
NI = adjusted number of POTWs in the Nation in stratum i.
The national estimate for the variance of this ratio estimator is
7-67
-------
Final Report
November 11, 1992
CHAP7.TSD
where
N.I = adjusted number of POTWs in the Nation in stratum i
ft = adjusted total number of POTWs in the Nation (8,497)
ni = number of POTWs selected for the analytic survey in stratum i
W = number of POTWs in stratum i
fl = TT
= number of POTWs in stratum i using or disposing sewage sludge in 1988
Y =
= -1-'1
N
The estimated stratum variance ($•?) is calculated from the following formula:
= S2ix + R2-s2iy - 2-R-pixy-six-siY
where
nf
\^ I V - V \ 2
= Pearson's product-moment correlation between X and Y in stratum i.
The 95% confidence interval about the estimated mean is calculated as
95% C.I. = R ± 1.96 -dr.
Empirical estimates of the median, 90th, 95th, and 98th percentile pollutant concentrations on a sewage
sludge mass basis are presented in Tables 7-20, 7-21, and 7-22 (presented at the end of this chapter).
Estimates are reported for each of the two substitution methods. For the estimated reported as SM-ML,
the minimum-level value was substituted for those POTWs from which a pollutant was not quantified
7-68
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Final Report
November 11, 1992
CHAP7.TSD
above the minimum level. The value zero was reported for those POTWs with a pollutant concentration
not quantified above the minimum level for those estimates reported as SM-O.
For a given pollutant, sewage sludge mass-based percentile estimates were determined first by ordering
POTW sewage sludge data from the smallest to the largest value of observed concentration values for a
pollutant. The amount of sewage sludge disposed by each POTW then was multipled by its survey weight
to estimate the amount of sewage sludge disposed in the Nation. The cumulative percent of sewage
sludge disposed then was estimated for the j* POTW by summing the weighted amounts of sewage sludge
disposed by the i= 1 through j* ordered POTWs, and dividing this cumulative quantity by the total mass
of sewage sludge disposed in the Nation. Concentration percentile estimates then were determined to be
the pollutant concentration associated with the POTW that corresponded to the pth percentile of the
cumulative mass of sewage sludge disposed.
7.6 SUMMARY COMMENTS CONCERNING STATISTICAL METHODS AND RESULTING
ESTIMATES OF POLLUTANT CONCENTRATION FROM THE NSSS
The multicensored, maximum-likelihood estimation (MLE) procedure used to estimate pollutant
concentrations under the assumption that pollutant concentrations follow a lognormal distribution was
selected, as discussed in Section 7.2, because it is the most robust technique available for estimating the
upper percentiles for the distribution. For those pollutants with low rates of censoring, particularly the
metallic pollutants, this method works particularly well, as illustrated in the graphical presentations of
the estimated cumulative distribution functions for each pollutant.
However, for those pollutants for which the rate of detection is either low or zero, MLE estimates are
either unreliable or nonestimable. In the case where detection rates are low, such as PCB-1254, the data
suggest it may not be valid to assume that pollutant concentrations follow a lognormal distribution. For
these pollutants, the nonparametric method of estimating pollutant concentrations, which substitutes the
sample-specific, minimum-level value for those samples from which a pollutant is not detected above the
minimum level, is consistent with a conservative estimate of risk.
The statistical methods used to estimate pollutant concentrations in the presence of the multiple censoring
points with the objective of producing the most statistically robust estimates were presented to the public
for comment in the technical support document for the NSSS Notice of Availability. In general,
comments from the public were favorable. In other cases, commentors referenced statistical techniques
presented by Dennis Helsel in his article entitled, "Less than Obvious: Statistical Treatment of Data
Below the Detection Limit"(p. 1766-1771). The methods presented by Dr. Helsel in this article were the
methods considered by the Agency and discussed in Section 7.2. Other commentors responded with
alternative statistical methods requiring the empirical measurement for those samples not quantified above
the minimum level of detection. Unfortunately, these measurements were not available for the NSSS.
7-69
-------
TABLE 7-14.
RATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE RATIONAL SEWAGE SLUDGE SURVEY
WEIGHTED BY AMOUNT OF SEWAGE SLUDGE DISPOSED
STANDARD DEVIATIONS AND CONFIDENCE INTERVALS FOR THE MEAN
POLLUTANTS OF CONCERN
Substitution
Pollutant Unit Method*
Aldrin/Dielcirin Mg/kg SM-ML
SM-0
SM-COM
Arsenic mg/kg SM-ML
SM-0
Benzene Mg/kg SM-ML
SM-0
T1 Benzo(A)Pyrene MS/kg SM-ML
O SM-0
Beryllium mg/kg SM-ML
SM-0
Bis(2-Ethylhexyl)Phthalate Mg/kg SM-ML
SM-0
Cadmium mg/kg SM-ML
SM-0
Cadmium1 mg/kg SM-ML
SM-0
Mean
19
0
10
11
8
842
1
13,800
21
0
0
110000
107000
38
38
38
37.
.90
.76
.50
.00
.88
.00
.61
.00
.50
.99
.16
.00
.00
.70
.10
.10
,50
Standard
Deviation
1.
0.
0.
0.
0.
75
1,250
0
0
9,890
9,610
3.
3.
3.
3.
78
07
.94
.99
.80
.80
.00
.09
.02
.00
.00
.49
.A3
.41
.35
Lower
Conf.
16.
0.
8.
9.
7.
694
11,400
0
0
90,500
88,000,
31.
31,
31.
30.
95X
Limit
40
63
63
04
32
.00
.00
.81
.14
.00
,00
,90
,40
,40
90
Upper
Conf.
23.
0.
12.
12.
10
991
16,300
1
0
129,000.
126,000.
45,
44.
44.
44.
95X
Limit
.40
.90
.30
.90
,50
.00
.00
.16
.19
.00
.00
.60
.80
.80
.00
* SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
SM-COM = Maximum Nondetect Set Equal to the Highest Minimum Level; Other Nondetects Set Equal to Zero.
• Estimates Generated After Deleting an Extreme Outlier Observation From Stratum 3.
. = Nonestitnable.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
-------
TABLE 7-14. (Continued)
RATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE RATIONAL SEWAGE SLUDGE SURVEY
WEIGHTED BY AMOUNT OF SEWAGE SLUDGE DISPOSED
STANDARD DEVIATIONS AND CONFIDENCE INTERVALS FOR THE MEAN
POLLUTANTS OF CONCERN
Substitution
Pollutant Unit Method*
Chlordane Mg/kg SM-ML
SM-0
Chromium mg/kg SM-ML
SM-0
Copper mg/kg SM-ML
SM-0
-J
^j DDT, Composite . (ig/kg SM-ML
^ SM-0
SM-COM
Heptachlor |ig/kg SM-ML
* ' ' _ SM-0
Hexachlorobenzene Mg/kg SM-ML
SM-0
Hexachlorobutadiene Mg/kg SM-ML
SM-0
Lead mg/kg SM-ML
SM-0
N
Mean
243.00
0.00
589.00
588.00
639.00
639.00
120.00
4.81
53.20
19.40
0.04
13,800.00
0.00
13,800.00
0.00
204.00
200.00
Standard
Deviation
21.70
53.00
52.90
57.50
57.50
10.80
0.43
4.76
1.74
1,240.00
1,240.00
18.40
18.00
Lower 95X
Conf. Limit
200.00
485.00
485.00
526.00
526.00
99.00
3.97
43.80
16.00
11,400.00
11,400.00
168.00
164.00
Upper 95X
Conf. Limit
285.00
693.00
692.00
752.00
752.00
141.00
5.66
62.50
22.80
16,300.00
16,300.00
240.00
235.00
* SM-ML - Nondetects Set Equal to the Minimum Level.
SM-0 " Nondetects Set Equal to Zero.
SM-COM - Maximum Nondetect Set Equal to the Highest Minimum Level; Other Nondetects Set Equal to Zero.
. = Nonestimable.
Note: DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDE, and 4,4'-DDT.
-------
TABLE 7-1*. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE RATIONAL SEWAGE SLUDGE SURVEY
WEIGHTED BY AMOUNT OF SEWAGE SLUDGE DISPOSED
STANDARD DEVIATIONS AND CONFIDENCE INTERVALS FOR THE MEAN
POLLUTANTS OF CONCERN
Pollutant Unit
Lindane yg/kg
Mercury mg/kg
;
Molybdenum mg/kg
N-Ni trosodimethy lamine jig/kg
Nickel mg/kg
PCB, Composite Mg/kg
Selenium mg/kg
Toxaphene Mg/kg
Substitution
Method*
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-COM
SM-ML
SM-0
SM-ML
SM-0
Mean
24.
0.
3.
2
11.
8
69,100
0
90.
87.
1,530.
197.
392.
6.
3.
971.
0.
.60
.26
.24
.62
. 10
.20
.00
.00
.60
.40
.00
.00
00
14
45
00
00
Standard
Deviation
2
0
0
1
0
6,220
8
7
137
17
35
0
0
87.
.20
.29
.24
.00
.74
.00
.16
.86
.00
.70
.10
.55
.31
.00
Lower
Conf.
20,
2
2
9
6
56,900
74
72
1,260
163
323
5.
2
801.
951
Limit
.30
.66
.16
.12
.75
.00
.70
.00
.00
.00
.00
.06
.84
.00
Upper
Conf.
28.
3
3
13
9
81,300
107
103
1,800.
232.
460.
7.
4.
1,140.
95X
Limit
.90
.81
.08
.00
.64
.00
.00
.00
.00
.00
.00
22
.06
00
* SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 - Nondetects Set Equal to Zero.
SM-COM = Maximum Nondetect Set Equal to the Highest Minimum Level; Other Nondetects Set Equal to Zero.
. = Nonestimable.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-14. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE RATIONAL SEWAGE SLUDGE SURVEY
WEIGHTED BY AMOUNT OF SEWAGE SLUDGE DISPOSED
STANDARD DEVIATIONS AND CONFIDENCE INTERVALS FOR THE MEAN
POLLUTANTS OF CONCERN
Pollutant
Unit
Substitution
Method*
Mean
Standard
Deviation
Lower 95X
Conf. Limit
Upper 951
Conf. Limit
Trichloroethene
Zinc
MgAg
rag/kg
SM-ML
SM-0
SM-ML
SM-0
858.00
20.90
1.490.00
1,490.00
77.20
134.00
134.00
707.00
1,230.00
1,230.00
1,010.00
1,750.00
1,750.00
* SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
. = Nonestimable.
-------
TABLE 7-15.
RATIONAL POLLUTAHT CONCENTRATION ESTIMATES FROM THE RATIONAL SEHAGE SLUDGE SURVEY
WEIGHTED BY AMOUNT OF SEHAGE SLUDGE DISPOSED
STANDARD DEVIATIONS AND CONFIDENCE INTERVALS FOR THE MEAN
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Substitution
Pollutant Unit Method*
Aldrin/Dieldrin Mg/kg SM-ML
SM-0
SM-COM
Aldrin Mg/kg SM-ML
SM-0
Dieldrin Mg/kg SM-ML
^j SM-0
i
-4
*"• DDT, Composite Mg/kg SM-ML
SM-0
SM-COM
4,4' -ODD Mg/kg SM-ML
SM-0
4, 4 '-DDE Mg/kg SM-ML
SM-0
4, 4 '-DDT Mg/kg SM-ML
SM-0
Mean
19.
0.
10.
10.
0.
9.
0.
120
4
53
50
2
49
1
20
0
90
76
50
10
.63
.78
.13
.00
.81
.20
.40
.16
.70
.67
.00
.98
Standard
Deviation
1.
0.
0.
0.
0.
0,
10
0
4
4
4
1
0
78
07
.94
.91
,06
.88
.80
.43
.76
.52
.45
.79
.09
Lower 95X
Conf. Limit
16.
0.
8.
8.
0.
8.
99
3
43
41
40
16
0
40
63
63
35
52
.07
.00
.97
.80
.60
.90
.50
.81
Upper
Conf.
23.
0.
12.
11.
0.
11
141
5
62
59
58
23
1
951
Limit
40
90
.30
.90
.74
.50
.00
.66
.50
.30
.40
.50
.15
* SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 " Nondetects Set Equal to Zero.
SM-COM = Maximum Nondetect Set Equal to the Highest Minimum Level; Other Nondetects Set Equal to Zero.
. = Nonestimable.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDE, and 4,4'-DDT.
-------
TABLE 7-15. (Continued)
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE NATIONAL SEWAGE SLUDGE SURVEY
WEIGHTED BY AMOUNT OF SEWAGE SLUDGE DISPOSED
STANDARD DEVIATIONS AND CONFIDENCE INTERVALS FOR THE MEAN
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
PCB, Composite
PCB-1016
PCB-1221
PCB- 1232
PCB-1242
PCB-1248
PCB- 1254
PCB-1260
Unit
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Mg/kg
Substitution
Method*
SM-ML
SM-0
SM-COM
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
Mean
1,530.00
197.00
392.00
194.00
0.00
194.00
0.00
194.00
0.00
194.00
0.00
223.00
39.80
317.00
132.00
215.00
25.80
Standard
Deviation
137.00
17.70
35.10
17.40
17.40
17.40
17.40
19.90
3.57
28.40
11.80
19.20
2.31
Lower 95Z
Conf. Limit
1,260.00
163.00
323.00 '
160.00
160.00
160.00
160.00
183.00
32.90
261.00
109.00
177.00
21.30
Upper 951
Conf. Limit
1,800.00
232.00
460.00
228.00
228.00
228.00
228.00
262.00
46.80
372.00
155.00
252.00
30.30
* SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
SM-COM = Maximum Nondetect Set Equal to the Highest Minimum Level; Other Nondetects Set Equal to Zero.
. = Nonestimable.
Note: PCB, Composite is a combination of PCB-1016. PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-16.
NATIONAL POLLUTANT CONCENTRATION ESTIMATES FROM THE RATIONAL SEWAGE SLUDGE SURVEY
WEIGHTED BY AMOUNT OF SEWAGE SLUDGE DISPOSED
STANDARD DEVIATIONS AND CONFIDENCE INTERVALS FOR THE MEAN
PERCENT SOLIDS. PHOSPHORUS, AND TOTAL KJELDAHL NITROGEN
Pollutant Unit
Percent Solids X
Phosphorus mg/kg
Total Kjeldahl Nitrogen mg/kg
Substitution
Method*
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
Mean
26.80
26.80
1,850.00
1,850.00
42,800.00
42,800.00
Standard
Deviation
2.41
2.41
167.00
167.00
3,850.00
3,850.00
Lower 95Z
Conf. Limit
22.00
22.00
1,520.00
1,520.00
35,300.00
35,300.00
Upper 95Z
Conf. Limit
31.50
31.50
2,180.00
2,180.00
50,400.00
50,400.00
ON
SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
-------
TABLE 7-17.
ESTIMATED GGBBELAXION
BETWEEN POLUJTAHT CONCENTRATION AHD SEWAGE SLUDGE DRY HEIGHT DISPOSED
POLLUTANTS OF CONCERN
Pollutant
Aldrin/Dieldrin
Arsenic
Benzene
Benzo(A)pyrene
Beryllium
Estimation
Procedure*
SM-ML
SM-0
SM-CCM
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
Stratum
> 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <" 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <- 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <» 10
FLOW <- 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <«• 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <= 10
FLOW <= 1
> 100 MGD
10 < FLOW <• 100
1 < FLOW <- 10
FLOW <- 1
Correlation
Coefficient
-0.4146
-0.0655
-0.1162
-0.1225
-0.1276
-0.0902
-0.0984
-0.1032
-0.3044
-0.0856
-0.1362
-0.1447
-0.0934
-0.0390
-0.1249
0.2218
0.0930
-0.0480
-0.0829
0.2035
-0.0318
-0.0152
-0.0955
0.0054
-0.1936
0.5136
0.1203
-0.0748
0 . 1592
-0.0442
-0.2202
-0.0878
-0.1091
-0.2542
-0.0472
-0.1359
-0.0123
D-Value
0.0776
0.6411
0.3727
0.4576
0.6025
0 . 5205
0.4504
0.5319
0.2051
0.5425
0.2954
0.3794
0.7038
0.7814
0.3335
0.1748
0.7049
0.7326
0.5218
0.2139
0.8971
0.9140
0.4602
0.9738
0.4271
0.0001
0.6238
0.5946
0.2164
0.7891
.
0.1132
0.4976
0.5085
0.2937
0.7374
0.2923
0.9409
* SM-ML = Nondetects set equal to the Minimum Level.
SM-0 ° Nondetects set equal to zero.
SM-COM - Maximum nondetect set equal to the highest minimum level; other nondetects set equal to zero.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
7-77
-------
TABLE 7-17. (Continued)
ESTIMATED CORRELATION COEFFICIENTS
BETWEEN POLLUTANT CONCENTRATION AHD SEWAGE SLUDGE DRY WEIGHT DISPOSED
POLLUTANTS OF CONCERN
Estimation
Pollutant Procedure*
Beryllium SM-0
Bis(2-Ethylheryl) Phthalate SM-ML
SM-0
Cadmium SM-ML
SM-0
Cadmiunf SM-ML
SM-0
Chlordane SM-ML
SM-0
Chromium SM-ML
Stratum
> 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <= 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <= 1C)
FLOW <• 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <«= 1
> 100 MGD
10 < FLOW <" 100
1 < FLOW <=• 10
FLOW <» 1
Correlation
Coefficient
0.2979
-0.0738
-0.1127
-0.1107
0.2504
-0.1362
0.1131
0.0331
0.2509
-0.1088
0.1128
0.0575
0.2305
0.0556
-0.0688
-0.1106
0.2356
0.0563
-0.0678
-0.2093
0.2305
0.0556
0.0264
-0.1106
0.2356
0.0563
0.0508
-0.2093
-0.3975
-0.0027
-0.0959
-0.1041
0.5893
-0.1949
0.6846
-0.0837
p-Value
0.2154
0.5994
0.3833
0.5023
0.3012
0.3310
0.3816
0.8412
0.3001
0.4381
0.3828
0.7280
0.3424
0.6928
0.5953
0.5026
0.3315
0.6890
0.6006
0.2010
0.3424
0.6928
0.8401
0.5026
0.3315
0.6890
0.6971
0.2010
0.0919
0.9847
0.4622
0.5282
0.0079
0.1620
0.0001
0.6123
' SM-ML = Nondetects set equal to the Minimum Level.
SM-0 = Nondetects set equal to zero.
Estimates generated after deleting an extreme outlier observation from stratum 3.
7-78
-------
TABLE 7-17. (Continued)
ESTIMATED COBBELAIION COEFFICIENTS
BETNEEH POLLUTAHT CONCENTRATION ADD SEWAGE SLUDGE DRY HEIGHT DISPOSED
PQLLOTAHTS OF COHCEBH
Pollutant
Chromium
Copper
DOT, Composite
Heptachlor
Hexachlorobenzene
Estimation
Procedure* Stratum
SM-0 > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
SM-ML > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
SM-0 > 100 MGD
10 < FLOW <» 100
1 < FLOW <- 10
FLOW <= 1
SM-ML > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <" 1
SM-0 > 100 MGD
10 < FLOW <• 100
1 < FLOW <- 10
FLOW <- 1
SM-COM > 100 MGD
10 < FLOW <- 100
1 < FLOW <" 10
FLOW <- 1
SM-ML > 100 MGD
10 < FLOW <• 100
1 < FLOW <- 10
FLOW <- 1
SM-0 > 100 MGD
10 < FLOW <• 100
1 < FLOW <- 10
FLOW <- 1
SM-ML > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
SM-0 > 100 MGD
10 < FLOW '<- 100
1 < FLOW <- 10
FLOW <- 1
Correlation
Coefficient
0.5893
-0.1949
0.6846
-0.0883
-0.0804
-0.2031
-0.1303
-0.1016
-0.0804
-0.2031
-0.1303
-0.1016
-0.2254
-0.0328
-0.1000
-0.1056
-0.1205
-0.0855
-0.0540
-0.1091
-0.1646
-0.0615
-0.1092
-0.1093
-0.3985
-0.0195
-0.0957
-0.1038
-0.1249
0.1203
-0.0474
0.1596
-0.0432
t
D-Value
0.0079
0.1620
0.0001
0.5931
0.7435
0.1447
0.3130
0.5384
0.7435
0.1447
0.3130
0.5384
0.3535
0.8154
0.4432
0.5221
0.6230
0.5425
0.6794
0.5085
0.5008
0.6619
0.4021
0.5079
0.0910
0.8897
0.4630
0.5295
0.3728
0.6238
0.7361
0.2153
0.7939
.
-
* SM-ML - Nondetects set equal to the Minimum Level.
SM-0 - Nondetects set equal to zero.
SM-COM = Maximum nondetect set equal to the highest minimum level; other nondetects set equal to zero.
Note: DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDE, and 4,4'-DDT.
7-79
-------
TATU.E 7-17. (Continued)
ESTIMATED OORBELATIOH COEFFICIEHTS
BETWEEH POLLUTAHT COHCEHTHATIOH AMD SEHAGE SLUDGE DRY HEIGHT DISPOSED
POLLUTANTS OF COHCEKB
Pollutant
Hexachlorobutadiene
Lead
Lindane (Gamma-BHC )
Mercury
Molybdenum
N-Nitrosodimethylamine
Estimation
Procedure*
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
Stratum
> 100 MOD
10 < FLOW <=• 100
1 < FLOW <= 10
FLOW <= 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <= 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <° 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <= 10
FLOW <- 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <= 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <• 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <- 1
Correlation
Coefficient
0.1203
-0.0474
0.1596
-0.0432
0.3697
-0.1255
-0.0772
0.0016
0.3697
-0.1233
-0.0199
-0.0303
-0.3981
-0.0147
-0.0996
-0.1054
-0.0353
-0.0453
-0.2905
-0.0878
-0.1434
-0.0733
-0.1092
-0.0330
-0.0714
-0.0770
-0.0202
-0.2731
-0.1233
-0.0395
0.3298
-0.2635
0.0039
-0.2112
0.1203
-0.0474
0.1596
-0.0432
p-Value
0.6238
0.7361
0.2153
0.7939
0.1193
0.3704
0.5507
0.9922
0.1193
0.3792
0.8781
0.8549
0.0914
0.9165
0.4452
0.5230
0.8016
0.7286
0.2276
0.5318
0.2663
0.6573
0.6564
0.8145
0.5812
0.6411
0.9347
0.0478
0.3398
0.8114
0.1679
0.0566
0.9761
0.1969
0.623B
0.7361
0.2153
0.7939
SM-ML = Nondetects set equal to the Minimum Level.
SM-0 - Nondetects set equal to zero.
7-80
-------
TABLE 7-17. (Continued)
ESTIMATED
BETWEEN POLLUTANT COHCENTHATION AND SEWAGE SLUDGE DRY HEIGHT DISPOSED
POLLUTANTS OF CONCERN
Pollutant
Estimation
Procedure*
Stratum
Correlation
Coefficient
p-Value
N-Nitrosodimethylamine
Nickel
PCS,Composite
Selenium
Tozaphene
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-COM
SM-ML
SM-0
SM-ML
> 100 MOD
10 < FLOW <" 100
1 < FLOW <- 10
FLOW <= 1
> 100 MGO
10 < FLOW <" 100
1 < FLOW <= 10
FLOW <= 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <= 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <» 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <= 10
FLOW <= 1
> 100 MGD
10 < FLOW <= 100
1 < FLOW <• 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
0.3132
-0.1666
0.1236
-0.1062
0.3195
-0.1660
0.1691
-0.1640
0.0869
-0.1084
-0.1111
-0.097*
0.4476
-0.1018
-0.1017
-0.0267
0.4226
-0.1028
-0.1487
-0.0513
0.2088
0.0230
0.0748
0946
-0
-0.0077
-0.4204
-0.1138
-0.1387
-0.3977
-0.0028
-0.0959
-0.1041
0.1916
0.2332
0.3386
0.5198
0.1823
0.2349
0.1890
0.3186
0.7235
0.4397
0.3938
0.5554
0.0547
0.4683
0.4353
0.8720
0.0715
0.4639
0.2526
0.7564
0.3910
O.B701
0.5636
0.5669
0.9750
0.0017
0.3785
0.3997
0.0917
0.9843
0.4623
0.5281
SM-0
> 100 MGD
10 < FLOW <- 100
1 < FLOW <• 10
FLOW <- 1
* SM-ML - Nondetects set equal to the Minimum Level.
SM-0 • Nondetects set equal to zero.
SM-COM - Maximum nondetect set equal to the highest minimum level; other nondetects set equal to zero.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254,
and FCB-1260.
7-81
-------
TABLE 7-17. (Continued)
ESTIMATED CORRELATION COEFFICIENTS
BETWEEN POLLUTANT CONCENTRATION AND SEWAGE SLUDGE DRY WEIGHT DISPOSED
POLLUTANTS OF CONCERN
Pollutant
Estimation
Procedure*
Stratum
Correlation
Coefficient
p-Value
Trichloroethene
Zinc
SM-ML
SM-0
SM-ML
SM-0
> 100 MOD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
> 100 MOD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
> 100 MOD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MOD
10 < FLOW <= 1CIO
1 < FLOW <- 1CI
FLOW <- 1
-0
0.0284
0.0164
0985
0.0054
-0.1475
-0.0403
-0.0349
0.3363
-0.2165
-0.0619
-0.1599
0.3363
-0.2165
-0.0619
-0.1599
0.9080
0.9072
0.4463
0.9738
0.5468
0.7744
0.7880
0.1592
0.1194
0.6325
0.3309
1592
1194
6325
0.3309
SM-ML = Nondetects set equal to the Minimum Level.
SM-0 " Nondetects set equal to zero.
7-82
-------
TABLE 7-18.
ESTIMATED CORRELATION COEFFICIENTS
BETVJEEH FQLLDXABT CONCENTRATION AND SEWAGE SLUDGE DRY HEIGHT DISPOSED
INDIVIDUAL POLLUTANTS FOR COMPOSITE FOLLUTAHTS OF CONCERN
Estimation
Pollutant Procedure* Stratum
Aldrin/Dieldrin SM-ML > 100 MGD
10 < FLOW <• 100
1 < FLOW <- 10
FLOW <- 1
SM-0 > 100 MGD
10 < FLOW <» 100
1 < FLOW <• 10
FLOW <- 1
SMrCOM > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <" 1
Aldrin SM-ML > 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <- 1
SM-0 > 100 MGD
10 < FLOW <» 100
1 < FLOW <- 10
FLOW <• 1
Dieldrin SM-ML > 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <- 1
SM-0 > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
DDT, Composite . SM-ML > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
SM-0 > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
SM-COM > 100 MGD
10 < FLOW <• 100
1 < FLOW <- 10
FLOW <- 1
Correlation
Coefficient
-0.4146
-0.0655
-011162
-0.1225
-0.1276
-0.0902
-0.0984
-0.1032
-0.3044
-0.0856
-0.1362
-0.1447
-0.3865
-0.0844
-0.1015
-0.1077
-0.0352
-0.0902
-0.0290
-0.0119
-0.3692
-0.0023
-0.1252
-0.1338
-0.1207
-0.0959
-0.1086
-0.2254
-0.0328
-0.1000
-0.1056
-0.1205
-0.0855
-0.0540
-0.1091
-0.1646
-0.0615
-0.1092
-0.1093
D-Value
0.0776
0.6411
0.3727
0.4576
0.6025
0.5205
0.4504
0.5319
0.2051
0.5425
0.2954
0.3794
0 . 1022
0.5481
0.4362
0.5140
0.8662
0.5205
0.8246
0.9427
0.1198
0.9867
0.3362
0.4166
0 . 6226
0.4620
0.5103
0.3535
0.8154
0.4432
0.5221
0.6230
0.5425
0.6794
0.5085
0.5008
0.6619
0.4021
0.5079
* SM-ML = Nondetects set equal to the Minimum Level.
SM-0 = Nondetects set equal to zero.
SM-COM - Maximum nondetect set equal to the highest minimum level; other nondetects set equal to zero.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
DDT, Composite is a combination of 4,4'-ODD, 4,4'-DDE, and 4,4'-DDT.
-------
TABLE 7-18. (Continued)
ESTIMATED CORRELATION COEFFICIENTS
BETHEEH POLLUTANT CONCENTRATION AHD SEWAGE SLUDGE DRY WEIGHT DISPOSED
XUDIVIDUAL POLLUTAHTS FOR COMPOSITE POLLUTANTS OF CONCERN
Estimation
Pollutant Procedure* Stratum
A, 4 '-ODD SM-ML > 100 MOD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <= 1
SM-0 > 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <= 1
4, 4 '-DDE SM-ML > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <- 1
SM-0 > 100 MGD
10 < FLOW <= 100
1 < FLOW <- 10
FLOW <- 1
4 ',4 '-DDT SM-ML > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
SM-0 > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
PCS, Composite SM-ML > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <- 1
SM-0 > 100 MGD
10 < FLOW <- 100
1 < FLOW <= 10
FLOW <- 1
SM-COM > 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <= 1
PCB-1016 SM-ML > 100 MGD
10 < FLOW <= 100
1 < FLOW <= 10
FLOW <- 1
Correlation
Coefficient
-0.1745
-0.0028
-0.0959
-0.1051
-0.1048
-0.2570
-0.0022
-0.1027
-0.1051
-0.1048
0.0635
-0.0426
-0.3430
-0.0838
-0.0999
-0.1083
-0.1636
-0.0954
-0.0611
-0.1091
0.0869
-0.1084
-0.1111
-0.0974
0.4476
-0.1018
-0.1017
-0.0267
0.4226
-0.1028
-0.1487
-0.0513
-0.3980
-0.0027
-0.0959
-0.1043
p-Value
0.4750
0.9842
0.4623
0.5243
0.6693
0.2882
0.9873
0.4312
0.5243
0.6693
0.6516
0.7444
0.1505
0.5507
0.4436
0.5117
0.5033
0.4967
0.6400
0.5085
0.7235
0.4397
0.3938
0.5554
0.0547
0.4683
0.4353
0.8720
0.0715
0.4639
0.2526
0.7564
0.0915
0.9847
0.4624
0.5275
* SM-ML = Nondetects set equal to the Minimum Level.
SM-0 = Nondetects set equal to zero.
SM-COM - Maximum nondetect set equal to the highest minimum level; other nondetects set equal to zero.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254,
and PCB-1260.
7-84
-------
TABLE 7-18. (Continued)
ESTIMATED CORRELATION
BETWEEN POLLUTANT CONCENTRATION AHD SEWAGE SLUDGE DRY HEIGHT DISPOSED
INDIVIDUAL POLLUTANTS FOR COMPOSITE FOLLOTANTS OF CONCERN
Pollutant
Estimation
Procedure*
Correlation
Coefficient
p-Value
PCB-1016
PCB-1221
PCB-1232
PCB-1242
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <• 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <= 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <= 10
FLOW <- 1
> 100 MGD
10 < FLOW <" 100
1 < FLOW <- 10
FLOW <" 1
> 100 MGD
10 < FLOW <• 100
1 < FLOW <- 10
FLOW <- 1
-0.3980
-0.0027
-0.0959
-0.1043
-0.3980
-0.0027
-0.0959
-0.1043
-0.3980
-0.0027
-0.0959
-0.1043
0.0915
0.9847
0.4624
0.5275
0.0915
0.9847
0.4624
0.5275
0.0915
0.9847
0.4624
0.5275
PCB-1248
PCB-1254
SM-0
SM-ML
SM-0
SM-ML
SM-0
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <" 100
1 < FLOW <" 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <= 10
FLOW <" 1
-0.4132
-0.1118
-0.1274
-0.1188
-0.1717
-0.0922
-0.0868
-0.1589
0.7399
-0.0680
-0.1050
-0.0594
0.7680
-0.0726
-0.0388
-0.0363
0.0787
0.4254
0.3279
0.4711
0.4821
0.5113
0.5058
0.3339
0.0003
0.6287
0.4207
0.7196
0.0001
0.6053
0.7663
0.8264
SM-ML - Nondetects set equal to the Minimum Level.
SM-0 «• Nondetects set equal to zero.
7-85
-------
TABLE 7-18. (Continued)
ESTIMATED CORRELATION COEFFICIENTS
BETWEEH POLLDTAHT COHCERTBATIOH AND SEWAGE SLUDGE DRY WEIGHT DISPOSED
IHDIVTDUAL POLLUTAHTS FOR COMPOSITE FOLLUTAHTS OF CONCEBH
Estimation
Pollutant Procedure* Stratum
PCS- 1260 SM-ML > 100 MGD
10 < FLOW <-
1 < FLOW <-
FLOW <=
SM-0 > 100 MGD
10 < FLOW <=
1 < FLOW <=
FLOW <=
Correlation
Coefficient
100
10
1
100
10
1
-0
-0
-0
-0
-0
-0.
-0.
0,
.377*
.0152
:li59
.0305
.2165
.0188
.0670
,0347
p-Value
0
0
0
0
0.
0.
0.
0.
.1112
.9138
.3738
.8536
.3733
,8937
6077
8340
SM-ML • Nondetects set equal to the Minimum Level.
SM-0 = Nondetects set equal to zero.
7-86
-------
TABLE 7-19.
ESTIMATED CORRELATION COEFFICIENTS
BETHEEH FQLLUTAHT COHCENTBATIOR AND SEWAGE SLUDGE DRY HEIGHT DISPOSED
PEBCEHT SOLIDS. FBOSFHCBIIS. AND TOTAL KJELDABL NITROGEN
Pollutant
Estimation
Procedure*
Stratum
Correlation
Coefficient
p-Value
Percent Solids
SM-ML
SM-0
> 100 MOD
10 < FLOW <" 100
1 < FLOW <- 10
FLOW <- 1
> 100 MCD
10 < FLOW <" 100
1 < FLOW <- 10
FLOW <- 1
0.3408
-0
0265
0:1304
0.0549
0.3408
-0
0285
0.1304
0.0549
1534
8394
3124
7399
0.1534
0.8394
0.3124
0.7399
Phosphorus
SM-ML
SM-0
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <= 10
FLOW <- 1
-0
0.1739
0.1102
0.1099
0397
0.4765
-0.1739
-0.1102
-0.1099
-0.0397
4322
3953
0.8102
0.4765
0.4322
0.3953
0.8102
Total Kjeldahl Nitrogen SM-ML
SM-0
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <- 1
> 100 MGD
10 < FLOW <- 100
1 < FLOW <- 10
FLOW <• 1
-0.3412
-0.0728
-0.0616
0.0854
-0.3412
-0.0728
-0.0616
0.0854
0.1528
0.6043
0.6341
0.6052
0.1528
0.6043
0.6341
0.6052
SM-ML = Nondetects set equal to the Minimum Level.
SM-0 = Nondetects set equal to zero.
-------
CO
CO
TABLE 7-20.
NATIONAL SEWAGE SLUDGE MASS BASED POLLUTANT CONCENTRATION PERCENTILE ESTIMATES
POLLUTANTS OF CONCERN
Pollutant
Aldrin/Dieldrin
Arsenic
Benzene
Benzo(A)pyrene
Beryl lium
Bis(2-Ethylhexyl)Phthalate
Cadmium
Cadmium*
Unit
M9/kg
n9/kg
Mg/kg
mg/kg
mg/kg
i»g/kg
pg/kg
i«g/kg
i»g/kg
mg/kg
mg/kg
eg/kg
eg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Substitution
Method*
SM-ML
SM-0
SH-COH
SH-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
Median
20.00
0.00
10.00
6.70
5.20
272.00
0.00
6.670.00
0.00
0.70
0.00
63.300.00
61,700.00
8.95
8.80
8.95
8.80
90th
Percent He
27.00
0.00
15.10
15.00
14.90
1.920.00
0.00
21,300.00
0.00
1.90
0.57
235,000.00
235,000.00
128.00
128.00
128.00
128.00
95th
Percenti le
34.00
0.00
22.00
23.70
19.50
5,260.00
0.00
43,500.00
0.00
2.70
0.72
264,000.00
264,000.00
128.00
128.00
128.00
128.00
98th
Percent i le
47.10
18.50
32.50
41.20
41.20
8,770.00
6.24
100,000.00
0.00
4.00
0.90
379,000.00
379,000.00
210.00
210.00
210.00
210.00
* SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
SM-COM = Maximum Nondetect Set Equal to the Highest Minimum Level; Other Nondetects Set Equal to Zero.
Estimates Generated After Deleting an Extreme Outlier Observation From Stratum 3.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
-------
TABLE 7-20. (Continued)
NATIONAL SEIMGE SLUDGE MASS BASED POLLUTANT CONCENTRATION PERCENTILE ESTIMATES
POLLUTANTS OF CONCERN
Pollutant
Chlordane
Chromium
Copper
DDT.
-J
vo Heptachlor
Hexach I orobenzene
Hexachlorobutadiene
Lead
Unit
M9/kg
t>9/kg
mg/kg
mg/kg
mg/kg
mg/kg
M9/kg
eg/kg
Mg/kg
pg/kg
t>g/kg
eg/kg
i>g/kg
eg/kg
M9/kg
mg/kg
mg/kg
Substitution
Method*
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-COM
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
Median
250.00
0.00
150.00
150.00
444.00
444.00
120.00
0.00
50.00
20.00
0.00
6,670.00
0.00
6,670.00
0.00
152.00
152.00
90th
Percent ile
311.00
0.00
1,670.00
1,670.00
1,180.00
1,180.00
156.00
0.00
71.80
24.80
0.00
21,300.00
0.00
21,300.00
0.00
472.00
472.00
95th
Percent ile
416.00
0.00
2.320.00
2.320.00
1.790.00
1.790.00
206.00
0.00
86.00
33.10
0.00
43,500.00
0.00
43.500.00
0.00
472.00
472.00
98th
Percent ile
556.00
0.00
2,320.00
2,320.00
2,120.00
2,120.00
272.00
30.30
166.00
44.00
0.00
100,000.00
0.00
100,000.00
0.00
525.00
522.00
* SM-ML = Nondetects Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
SM-COM = Maximum Nondetect Set Equal to the Highest Minimum Level; Other Nondetects Set Equal to Zero.
Note: DDT, Composite is a combination of 4.4'-DDD, 4,4'-DDE, and 4,4'-DDT.
-------
TABLE 7-20. (Continued)
NATIONAL SEWAGE SLUDGE MASS BASED POLLUTANT CONCENTRATION PERCENTILE ESTIMATES
POLLUTANTS OF CONCERN
Pollutant
L i ndane
Mercury
Molybdenum
N-Nitrosodimethylamine
Nickel
PCB, Composite
Selenium
Toxaphene
Unit
Mg/kg
Mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
Mg/kg
Mg/kg
mg/kg
mg/kg
Mg/kg
Mu/'kg
mg/kg
mg/kg
Mg/kg
Mg/kg
Substitution
Method*
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
SH-COH
SM-ML
SM-0
SM-ML
SM-0
Median
25.00
0.00
2.30
1.90
8.30
6.60
33,300.00
0.00
46.50
40.60
1,460.00
0.00
210.00
4.50
3.00
999.00
0.00
90th
Percent) le
32.10
0.00
6.70
5.55
20.10
17.00
106,000.00
0.00
236.00
236.00
2,020.00
822.00
1,020.00
13.00
6.60
1,240.00
0.00
95th
Percent He
43.00
0.00
8.70
7.00
29.70
24.70
217,000.00
0.00
236.00
236.00
2,390.00
1,470.00
1,550.00
16.90
10.60
1,670.00
0.00
98th
Percent He
56.00
0.00
11.30
8.30
43.50
37.30
500,000.00
0.00
390.00
390.00
3,120.00
1,470.00
1,550.00
23.50
15.70
2,220.00
0.00
* SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
SM-COM = Maximum Nondetect Set Equal to the Highest Minimum Level; Other Nondetects Set Equal to Zero.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-20. (Continued)
NATIONAL SEIMGE SLUDGE MASS BASED POLLUTANT CONCENTRATION PERCENTILE ESTIMATES
POLLUTANTS OF CONCERN
Pollutant
Trichloroethene
Zinc
Unit
f9/kg
eg/kg
mg/kg
mg/kg
Substitution
Method*
SM-HL
SH-0
SM-HL
SH-0
Median
272.00
0.00
970.00
970.00
90th
Percent ile
1,920.00
0.00
2,660.00
2,660.00
95th
Percent ile
5,260.00
0.00
3.390.00
3.390.00
98th
Percent ile
8,770.00
24.20
4,820.00
4,820.00
SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
-------
TABLE 7-21.
NATIONAL SEUAGE SLUDGE MASS BASED POLLUTANT CONCENTRATION PERCENTILE ESTIMATES
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant Unit
Aldrin/Dieldrin i»g/kg
eg/kg
Mg/kg
Aldrin Mg/kg
Mg/kg
Dieldrin Mg/kg
Mg/kg
DDT, Composite Mg/kg
--o Mg/kg
so Mg/kg
to
4,4'-DDD Mg/kg
Mg/kg
4, 4' -DDE Mg/kg
Mg/kg
4,4- -DDT Mg/kg
Mg/kg
Substitution
Method*
SM-HL
SH-0
SM-COM
SM-ML
SM-0
SH-HL
SM-0
SM-ML
SM-0
SM-COM
SM-ML
SM-0
SM-ML
SM-0
SM-ML
SM-0
Median
20.00
0.00
10.00
10.00
0.00
10.00
0.00
120.00
0.00
50.00
50.00
0.00
50.00
0.00
20.00
0.00
90th
Percent) le
27.00
0.00
15.10
14.30
0.00
12.90
0.00
156.00
0.00
71.80
64.30
0.00
64.80
0.00
27.50
0.00
95th
Percent ile
34.00
0.00
22.00
19.20
0.00
16.60
0.00
206.00
0.00
86.00
83.70
0.00
83.80
0.00
34.30
0.00
98th
Percent ile
47.10
18.50
32.50
22.40
6.52
22.30
0.00
272.00
30.30
166.00
113.00
0.00
113.00
0.00
45.40
0.00
* SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
SM-COM = Maximum Nondetect Set Equal to the Highest Minimum Level; Other Nondetects Set Equal to Zero.
Note: Aldrin/Dieldrin is a combination of Aldrin and Dieldrin.
DDT, Composite is a combination of 4,4'-DDD, 4,4'-DDE, and 4,4'-DDT.
-------
VO
TABLE 7-21. (Continued)
NATIONAL SEWAGE SLUDGE MASS BASED POLLUTANT CONCENTRATION PERCENTILE ESTIMATES
INDIVIDUAL POLLUTANTS FOR COMPOSITE POLLUTANTS OF CONCERN
Pollutant
PCB, Composite
PCB-1016
PCB- 1221
PCB-1232
PCB-1242
PCB-1248
PCB-1254
PCB-1260
Unit
eg/kg
ng/kg
ng/kg
eg/kg
i»g/kg
eg/kg
xg/kg
M9/kg
ng/kg
i«g/kg
i»g/kg
i>g/kg
M9/kg
i>g/kg
Substitution
Method*
SM-HL
SM-0
SM-COM
SM-HL
SM-0
SM-HL
SM-0
SM-ML
SM-0
SM-HL
SM-0
SM-HL
SM-0
SM-HL
SM-0
SM-ML
SM-0
Median
1,460.00
0.00
210.00
200.00
0.00
200.00
0.00
200.00
0.00
200.00
0.00
206.00
0.00
206.00
0.00
204.00
0.00
90th
Percent ile
2,020.00
822.00
1,020.00
248.00
0.00
248.00
0.00
248.00
0.00
248.00
0.00
351.00
0.00
446.00
0.00
305.00
0.00
95th
Percent ile
2,390.00
1.470.00
1.550.00
334.00
0.00
334.00
0.00
334.00
0.00
334.00
0.00
444.00
296.00
1.370.00
1,370.00
444.00
0.00
98th
Percent ile
3,120.00
1,470.00
1,550.00
444.00
0.00
444.00
0.00
444.00
0.00
444.00
0.00
522.00
468.00
1,370.00
1,370.00
596.00
330.00
* SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
SM-COM = Maximum Nondetect Set Equal to the Highest Minimum Level; Other Nondetects Set Equal to Zero.
Note: PCB, Composite is a combination of PCB-1016, PCB-1221, PCB-1232, PCB-1242, PCB-1248, PCB-1254, and PCB-1260.
-------
TABLE 7-22.
NATIONAL SEWAGE SLUDGE MASS BASED POLLUTANT CONCENTRATION PERCENTILE ESTIMATES
PERCENT SOLIDS, PHOSPHORUS. AND TOTAL KJELDAHL NITROGEN
Pollutant
Percent Solids
Phosphorus
Total Kjeldahl Nitrogen
Unit
%
%
mg/kg
mg/kg
mg/kg
mg/kg
Substitution
Method*
SM-HL
SM-0
SM-ML
SM-0
SM-ML
SM-0
Median
20.40
20.40
560.00
560.00
40,300.00
40,300.00
90th
Percent ile
64.00
64.00
5,850.00
5,850.00
73,000.00
73,000.00
95th
Percenti le
66.00
66.00
6,930.00
6,930.00
90,500.00
90,500.00
98th
Percent ile
71.40
71.40
12,600.00
12,600.00
102,000.00
102,000.00
SM-ML = Nondetects Set Equal to the Minimum Level.
SM-0 = Nondetects Set Equal to Zero.
-------
FIGURES 1-110
7-95
-------
WJ
M
60
a
o
• *H
•ft
ft
l-l
•»->
a
u
o
a
o
U
1000.00
100.00
10.00
1.00
0.10
0.01
0.1
x Minimum Level
—i 1 1—i—i—r~r~|—
X
J 1 I I I I I I
Above Minimum Level
i 1 1—i—i—r~r
~i 1 1 1—i—i—i—n
x
X,
X
X
X
1.0 10.0
Percent Solids
100.0
Figure 7-1. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of ALDRIN
-------
1000.00
100.00
1—4
S. 10.00
a
o
a
I i.oo
0
u
0.10
0.01
0.
x Minimum Level A Above Minimum Level
: i i i i i i i i | i i i i i i i i i i ir~ T — i — i — m
A A
r A -
1 A :
x v &Xx X v
— /\ y> &* "
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1.0 10.0 100.0
Percent Solids
Figure 7-2. Percent Solids of.NSSS Samples Versus
WET WEIGHT Concentrations of ALDRIN
-------
-J
00
1000.00
60
M
00
a
o
a
o
u
a
o
U
100.00
10.00
1.00
0.10
0.01
0.1
x Minimum Level
Above Minimum Level
X
"1 I 1—I—I—I I I
X
X
X
I I
1.0 10.0
Percent Solids
100.0
Figure 7-3. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of ARSENIC
-------
-J
vb
1000.00
BO
J
a
.3
-u
2
o
a
o
U
100.00
10.00
1.00
0.10
0.01
0.1
x Minimum Level
—i 1—i—i—i i i i—
A Above Minimum Level
~\ 1 1—i—i—i i i 1
A
X X X XX
A
A
VJ
x
X
J 1 1 I I I I 1
1.0
10.0
100.0
Percent Solids
Figure 7-4. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of ARSENIC
-------
x Minimum Level
Above Minimum Level
1UUUUU.U
10000.0
| 1000.0
w>
3
d
1 1 00.0
tl
+J
a
o
o
a
° 100
u
1.0
0 1
E 1 1 1 1 1 1 1 1 | 1 I 1 1 1 1 1 ! | 1 1 1 1 1 1 | |_
X X ~
XX J
: x/ X x E
- X x X Xx
X X I
\s/ \s V^C^^
*xS v>- 'Xj* X ^^^?^ -
_ x x x x
E x x XxXXxx^x x x x x -
; x>^ ^ x x x x x^fc^ >^ X :
-*^ %, X ^>$<
Xxx x<~ xx^x
r xx| AX
; X x^Sxl.., X E
X '^'VY^X XX ^
X ^Sx *, X ^X y
xx ^x^x^
X vv^x XxxX
/X Xhfc^
— X^X vv^^ >A
: :
- _
1 1 1 1 1 1 LJ 1 1 1 1 1 I I i_ 1 .. i i i i i i i i
0.1 1.0 10.0 100.0
Percent Solids
Figure 7-5. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of BENZENE
-------
-J
o
t-H
60
3
a
0
• *4
rt
IH
**
a
0
0
a
o
O
X Minimum Level A Above Minimum Level
100000.0
10000.0
1000.0
100.0
_
10.0
1.0
0.1
E I i I i i i i i | I I 1 1 — I — I I I | 1 1 1 1 — i — i i i-
— x -
" X
X
- x x x * -
~ -
<_
v
X x x X0< X
-X^
; .. v -
: x x x x x >? x:
x .
x, x x x x x *
^x ^ •&
X XXX
r xx >g *• ^xxW^^ ^c ^ x x xxxx|: %$$&*$< ^^Xxl^ >£
; X X X ^X X X yX^ "
- x xx x :
vx
- • _
.,,.., ,1 , 1
,
0.1 1.0 10.0 100.0
Percent Solids
Figure 7-6. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of BENZENE
-------
x Minimum Level
X
60
a
u
o
o
U
1000000
100000
10000
1000
100
10
0.1
A Above Minimum Level
~i i 1—i—i—i i i i :
x
X X
X
1 - \ - 1 - 1 _ 1 _ 1 _ 1 1
1
x
x x
x
X
x
X
><><
^ * w
X x XX x
X A ** x
X v -^ X
J I I I I I I I
1.0 10.0
Percent Solids
100.0
Figure 1-1. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of BENZO(A)PYRENE
-------
s
60
3
a
.2
*•>
5
a
o
o
a
o
U
1000000
100000
10000
1000
100
10
0.1
x Minimum Level
A Above Minimum Level
~l 1—I—I—I. I I
x
s/
X
X
>* x xx
x * xg
X X
x
x
X X
x
x
xx
x
-1 1—I—I I I I I 1 1 I I I I I I I
x x
X X
X
x
1.0 10.0
Percent Solids
100.0
Figure 7-8. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of BENZO(A)PYRENE
-------
--4
i
o
100.000
00
M
a
.2
•<->
rt
•«•»
a
a>
o
a
o
U
10.000
1.000
0.100
0.010
0.001
0.1
x Minimum Level
x
X
A Above Minimum Level
T i 1 1 I I I
X X
XX,,
vx
X
1 1 1 1—I—I I 1-1
X
X
X
£
AX XX
x x< x
1.0 10.0
Percent Solids
100.0
Figure 7-9. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of BERYLLIUM
-------
x Minimum Level
Above Minimum Level
8
1 UU.UUVJ
10.000
1 1.000
.2
•4»*
rt
IH
+•»
§ 0.100
Q
o
u
0.010
0.001
0
• i i — i — i — i i i i | 1 1 — i — i — i i i i | 1 1 — i — i — i i i i_
^ * AA 4^/1
A A ^^4^*^ A'
X /K^^A A A vx
: x xxw x± x :
X SK X XX XXXX XX&XX. X v»*&X X A ^ X X >^< A -
x x
X X x ^?< A X
- _
- x x :
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
1 1.0 10.0 100.0
Percent Solids
Figure 7-10. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of BERYLLIUM
-------
1000000
M
\
«
a
u
u
a
o
U
100000
10000
1000
100
10
0.1
x Minimum Level
A Above Minimum Level
"T 1 1 I—I I I I
1
A X
A A XXX
X
y v
X A A
X X
A A A
AA "
A
A A
X
1 ..... II
_i i 1—i i i i i
1.0 10.0
Percent Solids
100.0
Figure 7-11. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of BIS(2-ETHYLHEXYL) PHTHALATE
-------
X Minimum Level
A Above Minimum Level
1UUUUUU
100000
5 10000
a
.2
S
| 1000
o
u
100
10
0.
: ... i/T-r-n-i ' ' ' | 1 1 1 i I i I i-
A
A
- A AAAX
; A A ~
A A A A AA ^j± A '
1 A ^ XAA*^AA *A I
- AAA"A * * AX A :
AA AA ^A
-A ^ XA,XAXX X X X AA ^ :
x A A A
AAAX x_
: A E
: x N XA x x x • :
L
1 1.0 10.0 100.0
Percent Solids
Figure 7-12. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of BIS(2-ETHYLHEXYL) PHTHALATE
-------
x Minimum Level
o
oo
DO
M
\
60
J
a
o
"**
rt
o
a
o
U
10000.00
1000.00
100.00
10.00
1.00
0.10
0.01
0.1
X
X
A Above Minimum Level
"i i i i i i i | 1 1 1—i A i i i-
A
X
X
1.0 10.0
Percent Solids
100.0
Figure 7-13. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of CADMIUM
-------
x Minimum Level
J
a
o
a
o
o
a
o
U
10000.00
1000.00
100.00
10.00
1.00
0.10
0.01
0.1
Above Minimum Level
X
~T 1 1 1—I I I-
A :
AA A
A
AA
AX
X X
J 1 i i
1.0 10.0
Percent Solids
100.0
Figure 7-14. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of CADMIUM
-------
10000
1000
'fefi
M
1 100
2
a
u
u
a
o
U
10
1
0.
X Minimum Level A Above Minimum Level
: ' ' ' n ' ' ' ' | ' i~q 1 1 1 — i — i i j i.
X
X
X
- X
: x -
1 x x x ^x A x x :
X N^y ]& X "^ X
^ Xv ^K
'^aA'x
: x x>c
X '
x
x
1 1 1 — i — i i i i 1 i i i i i i i i 1 i |
1 1.0 10.0 100.0
Percent Solids
Figure 7-15. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of CHLORDANE
-------
x Minimum Level
A Above Minimum Level
1UUUU
1000
H
3
a
1 100
**
a
o
0
a
o
O
10
1
0.
- ' ' ' ' ' ' ' ' | " 1 — i — i — i i i i | 1 1 — i — i — i i i i.
"
X Y^
r £ **$$ x x x ~
y v v X *5^?v^ ^.
A A A v X X
X XX x^ x
x x x XXX"X x
A A s*''* X
^— J 1 1 I —l- 1 1 I 1 i I i i i i i i I , ii| | | | |
1 1.0 10.0 100.0
Percent Solids
Figure 7-16. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of CHLORDANE
-------
x Minimum Level
A Above Minimum Level
M
J*
tat
a
o
'•t-t
rt
o
a
o
U
10000.00
1000.00
100.00
10.00
1.00
0.10
0.01
0.1
A
A A
_l 1 I I I 1 I I
1.0 10.0
Percent Solids
100.0
Figure 7-17. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of CHROMIUM
-------
-4
U>
oo
J
a
.3
•M
2
•»-•
a
o
t>
a
o
U
10000.00
1000.00
100.00
10.00
1.00
0.10
0.01
0.1
x Minimum Level
—i 1—i—i—i i i —
A Above Minimum Level
"T 1 1 1 1—II I I
A A
A A
A A'
.
A A A AA A A
A ^ A 4kA A
*A*AA
A ^>
*CX A xx^
J 1 1—i—l i l
-l 1
1.0 10.0
Percent Solids
100.0
Figure 7-18. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of CHROMIUM
-------
10000.0
oo
.*
bo
J
a
o
a
o
o
a
o
U
1000.0
100.0
10.0
0.1
0.1
X Minimum Level
I 1 1 1—I—TT~I
A Above Minimum Level
~i i 1 r~i—i i i i 1
AA
1.0 10.0
Percent Solids
A
100.0
Figure 7-19. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of COPPER
-------
-4
GI
10000.0 E
M
J
fl
.2
**
2
•<->
a
0>
0
a
o
U
1000.0
100.0
10.0
1.0
0.1
0.1
x Minimum Level
—i 1—i—i—i i i —
A Above Minimum Level
-i—i—i—i i i i
* V
1
1.0 10.0
Percent Solids
100.0
Figure 7-20. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of COPPER
-------
1000.00
00
J4
60
a
o
o
a
o
U
100.00
10.00
1.00
0.10
0.01
0.1
x Minimum Level
X
X
A Above Minimum Level
~i—i—i—i i i i
X
X
x x x
X
A
A
X
XX X
X
X
X
-J 1 1—I—I I I I
-I 1 1—I I I I I
1.0 10.0
Percent Solids
100.0
Figure 7-21. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of DIELDRIN
-------
1000.00
a
.8
rt
u
u
a
o
U
100.00
10.00
100
0.10
0.01
0.1
X Minimum Level
A Above Minimum Level
~i 1—i—i—i i i i 1
*
1 1
1.0 10.0
Percent Solids
1 - 1 — i — ii
100.0
Figure 7-22. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of DIELDRIN
-------
00
o
M
\
BO
a
o
u
a
o
U
1000.0
100.0
10.0
1.0
0.1
0.1
x Minimum Level
x
x
X X
Above Minimum Level
~I 1—I—I—I I I
x
1 1 1 1 1 1 1 1
x
x
*
x
x
1.0 10.0
Percent Solids
100.0
Figure 7-23. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of HEPTACHLOR
-------
x Minimum Level
Above Minimum Level
a
a
o
U
a
o
U
1000.0
100.0 -
1.0 10.0
Percent Solids
100.0
Figure 7-24. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of HEPTACHLOR
-------
to
o
a
.8
rt
•M
a
o
o
o
U
1000000
100000
10000
1000
100
10
0.1
x Minimum Level
—i 1—i—i—i i i i—
x
A Above Minimum Level
~i i 1—i—i—i—r~n
x x
X
x x
1 - 1 - 1 - 1 — i — i — r~ r=
X
x
xx
x
x X
X
x xx
X
x
x
X
x<
X
x
i i
1.0 10.0
Percent Solids
100.0
Figure 1-25. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of HEXACHLOROBENZENE
-------
N>
~
M
3
*""^
a
JO
"•«••
rt
IH
**
a
0
o
a
o
U
X Minimum Level A Above Minimum Level
1000000
100000
10000
1000
100
10
1
\ ' ' ' 1 1 1 1 1 1 1 1 1 — 1 — 1 1 1 1 1 1 1 1 — 1 — 1 1 1 1.
r —
x x :
X
- X
: X —
X .. :
^< X v
X X X x JKP&fwit&X WsSK •^•Xv >?\X v>{<
^Wyt /«? ^~
x '
- xx % x x _
X^ -
\^f v> ~
I vX^-'^Xv"
x^ Xx^ ^x x x^^xXx^ x,,^ -
XXX x x X?^
V V
- . x X X )X Xe ^X _
• x M XxxXx xLx^ X X ^ -
x x x •
r x x x x
1 1 — i — i — i i i i 1 i i i i i i i i I , , ,,,,,,
0.1 1.0 10.0 100.0
Percent Solids
Figure 7-26. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of HEXACHLOROBENZENE
-------
x Minimum Level
A Above Minimum Level
-J
h—»
to
1UUUUUU
100000
9 10000
eo
-?i
a
•2 i (\f\f\
<-• i \j\j\j
eg
IH
•M
a
o
u
a
3 loo
10
1
= ' ' ~~1 i > ' ' ' | i ~i i — i — i — iiij 1 1 1 — i — i — i i [_
x
- x x x
- X :
1 v * x x x :
x * x xxx Xvx x -
x x x x x v ^^Ixv x^ x
r *xxX X;?x>5
-------
5
60
s»
^"^
a
o
•^"<
**
rt
Wl
**
a
u
u
a
o
U
x Minimum Level A Above Minimum Level
1000000
100000
10000
1000
100
10
I
| "!" 1 1 1 ' ' ' i | 1 1 1 1 — 1 I 1 1 | 1 1 1 1 — I I i i;
r —
xx :
X
X
: x -
x =
• x x, XxXx xv* •
X X X x !Ji£>S$Mr$X KZ&( ^-Xs/ >?cX X)^
^>'"T'W; 'vf " A
X
* X^ —
• N/ N/ V X ~
><0< ^^ X v> X
_ ^ \x X '^v ^^ \x \/ ^>v *)fC. ^^ XX ^"^C
X. X X \s X^
X XX X v X ^
~ x x x >^< J&. >{< !
?x ^ X jo( ^ 5
-------
•~J
I
to
10000.0
Mk
^
60
a
o
'-M
rt
M
•«->
a
u
u
a
o
U
1000.0
100.0
10.0
1.0
0.1
0.1
x Minimum Level
1 1—i—i—i i i i—
A Above Minimum Level
~i i—i—i—i i i i
i 1 1—i—i—i—rrq
A A
A AA
X
-1 1 I I I I I I
1.0 10.0
Percent Solids
100.0
Figure 7-29. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of LEAD
-------
X Minimum Level
Above Minimum Level
~J
*-*
K)
1 UUUU.U
1000.0
1 100.0
a
.8
i
i 10°
o
U
1.0
0.1
0.
: ' ' ' ' i ' ' ' | i " 1 1 — i i I i | 1 1 1 1 — i i i i-
" ^ -
" \ ^X ^ *
: AA^A* 1 AiA ^ a =
- AA A i Jft^ i^Sk, A
^AAA AAAAA*AAAAAAA A^ j
- A ^AA7A4 A A ^ -
- A AA ^ A AA A "
• ^i ^ ^^ *
— y *xf ^^ ^^ ib^w/^'v VN/ \/ ^^ v^
^V ^^ XV\ ^^^^^^^s ^.^ ^ p^ —
" x :
] A
1 1 1 — i — i — i — ' i 1 i 1 | i .
k
1 1.0 10.0 100.0
Percent Solids
Figure 7-30. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of LEAD
-------
K)
OS
x Minimum Level
A Above Minimum Level
1\J\J\J.\J
100.0
M
t>0
1 1 0.0
§
o
u
o
a
o
U
1.0
0.1
0.
^ ' i i i i i i i | i i r— i — i i i i | — — 1 1 1 — i — i i i i.
X
X
X
— X
- X ;
~ x X x v-X AX * I
X XX ^fe
~ X /^4
X -
X
X
: :
1 1.0 10.0 100.0
Percent Solids
Figure 7-31. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of LINDANE (GAMMA-BHC)
-------
x Minimum Level
Above Minimum Level
-jj
-J
J.UUU.U
100.0
60
3
a
1 1 0.0
•"«
a
o
o
a
o
U
1.0
01
: ' ' ' ' i i i i | i i 1 — i i i i i | 1 1 1 —
I
'- x *»«*»!
P\ S^\/\/ f^
X "^&^s^ 'V —
X .v^
x ^X>< X>
-------
ro
oo
a
M
M
d
o
*j
2
a
4>
O
a
o
U
100.00
10.00
1.00
o.io
x Minimum Level
A Above Minimum Level
"T 1 1 1 1—TT
k. A
~i 1 1 1—i—i i i-i
X
0.01
o.i
1 - 1 - 1 - 1 - 1 - 1 1 1
I I I I I I I I
1.0 10.0
Percent Solids
100.0
Figure 7-33. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of MERCURY
-------
x Minimum Level
Above Minimum Level
1UU.UU
10.00
J
1 10°
a
o
o
a
o
U
0.10
0.01
0.
; ' ' 1 1 1 1 1 1 | 1 1 1 1 1 — 1 1 1 | 1 1 1 1 1 — I I |_
A
I A :
I A -
A **
A A * A A*A
• ^>;-V^ AA:
- A */ A4 A AA
/^r\xw^vws /vx«x\ ^^^^^ MC* X
x :
X
x
— 1 1 1 1 L I 1 1 1 1 II 1 | , | | | | | | L
k
1 1.0 10.0 100.0
Percent Solids
Figure 7-34. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of MERCURY
-------
-J
I
O
1000.00
60
X
60
J
a
o
rt
a
o
u
o
o
U
100.00
10.00
100
0.10
0.01
0.1
x Minimum Level
A Above Minimum Level
~1 I 1 1 1 1—TT
X
;
x
1 - 1 - 1 — i — i — i — i
J 1 1 1 I L_l_
_L
1.0 10.0
Percent Solids
T—i—i—r~ra
AA
X
100.0
Figure 7-35. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of MOLYBDENUM
-------
X Minimum Level
A Above Minimum Level
1 00.00
J 1000
a
.8
-M
s
^J
8 1.00
a
0
u
0.10
0.01
0.
E ~l ' ' ' ' ' ' ' | i i 1 — i — i — i i i | 1 1 1 — i — i — i i i.
r * * A5 ^
" AAAAAAAAAAA-
- A A A A f^**** A*
- y \x w v^^^ ^^^r \/ ^c^^ ""
y '^'^ ^l AA^ O"N V* •^ ^ *^?N ""
A* X>X ^ A
-------
x Minimum Level
OJ
K)
10000000
00
M
00
3
a
o
o
a
o
U
1000000 r
100000
1 0000
1000
100
10
0.1
Above Minimum Level
x
X
X X
X
X
,.v
AX
X
x x
x • x
X
x
•"•
x
# x
x v x x
X
1.0 10.0
Percent Solids
100.0
Figure 7-37. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of N-NITROSODIMETHYLAMINE
-------
x Minimum Level
A Above Minimum Level
A UUUVFUUU
1000000
^ 100000
60
3
*"^
a
0
5 10000
I*
a
o
o
a
5 1000
100
10
: ' ' 1 1 1 1 1 1 | 1 1 1 1 — 1 1 1 1 | 1 1 1 1 I I I i-
r -
X X
: X ~E
v
A.
X
x ,
\J w ^f _
X X " X y&'yS&QfBkXx' ^g^Sf ^Af^sv 'iftc^ w^7
"^ vW»/""^RwC"' '^K^ ^^^'^S /x> o?V\
X -
' vx & X X ;
x1
~
v >C* X "^T ^ ^ y ~
v, ^ .. x O^>< ~=
N/ " \X y X \JtX >, v ~
v AX x1- x, /v\X
- x x x xxx ** :
xxxx x xx
* x xv x >$< x% xx
r x x x
: X :
; X x x ' :
1 1 — i — i — 'iiil 1 i i i i i i i 1 i
0.1
1.0 10.0
Percent Solids
100.0
Figure 7-38. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of N-NITROSODIMETHYLAMINE
-------
bQ
M
M
J3
a
o
a
*j
a
o
o
a
o
U
1000.00
100.00
10.00
1.00
0.10
0.01
0.1
x Minimum Level
x
A Above Minimum Level
A A
A A A
-I I I I I
1.0 10.0
Percent Solids
A A
A
100.0
Figure 7-39. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of NICKEL
-------
1
a
.8
•M
2
+••
8
ft
0
o
1000.00
1 00.00
1 0.00
1.00
0.10
0.01
01
x Minimum Level
I I 1 1 1—TTT
A Above Minimum Level
~i 1 1—i—i—i i i i 1
1 - 1 - 1 — i — i
1 --- 1 1
AAA
A
I I
J 1 I L.
1.0 10.0
Percent Solids
100.0
Figure 7-40. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of NICKEL
-------
10000
x Minimum Level
Above Minimum Level
i 1 1—i—i—r~r
"i 1 1 1—i—i—r~rq
-J
o\
DO
3
rt
d
u
o
o
o
U
1000
100
10
X
X
X
X X
X
X
X
X
XXX
X
X
XX X
X
XX
X
X
0.1
1.0 10.0
Percent Solids
100.0
Figure 7-41. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of PCB-1016
-------
~J
-J
60
a
o
a
o
u
a
o
U
10000
1000
100
10
0.1
x Minimum Level
xx
A Above Minimum Level
x x
XX
1 — 1 1 1
*x< X>
V v X
£ x
x
tf?
XxX
-I 1 I I I I I I I
1.0 10.0
Percent Solids
i.
100.0
Figure 7-42. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of PCB-1016
-------
x Minimum Level
Above Minimum Level
I \J\J\J\J
1000
^_^
og
X
bo
^3
""""
a
1 100
cU
IH
<-«
a
o
o
a
o
U
10
1
E ' ' ' ' ' ' ' ' i ' ' i T — i i i i | r— — i — i — i — i i i i_
x
x
— x _
X
IX -
-
'- x x x x x x -
\S '\s'^ \/ &^\s ^ /%* V —
^>S s*** \X V V \%eC$$v'£s & X ^ XX ^K^S^QK' XV Nrf
^^ ^v^v^ x '^^^I^^^C^fe^:
x ^ x x x '^^^•^^^fe
- x X X X xx ^L
— 'VB'fcy' ~
•— X X^
X ^
—
X
"
X
—
1 1 1 — 1 — 1 — 1 1 1 1 1 1 1 1 1 1 1 l_l. 1 , 1111,1
1 • — • • • — • — ' — ' — •— '
0.1 1.0 10.0 100.0
Percent Solids
Figure 7-43. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of PCB-1221
-------
10000
x Minimum Level
A Above Minimum Level
~i 1—i—i i i I • 1 1 r
-J
VO
60
3
a
.2
-•-»
2
a
u
u
. a
o
U
1000
100
10
0.1
1 - 1 - 1 — 1 — 1 — 1 1 1
1.0 10.0
Percent Solids
100.0
Figure 7-44. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of PCB-1221
-------
x Minimum Level
Above Minimum Level
-J
I
o
1 UUUU
1000
^^
bo
M
00
>~-"
a
1 10°
ea
*J
a
o
o
a
o
U
10
]
: ' r" ' ' ' ' ' ' | i i i i i i i i | 1 1 1 — i — i i i i.
x
x
— x
X
: x :
-
x x x v$^ x •^98||NRSk^&>&
^ x xxx ^^^-^^^5^
- x X>< X xx ^L -
- v ^^Xv-
X ^
-
~
X
k
X
^ ;
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 I | | i i i ,
o.i
1.0 10.0
Percent Solids
100.0
Figure 7-45. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of PCB-1232
-------
M
a
.2
•»•»
s
-t->
a
o
u
a
o
U
10000
1000
100
10
0.1
x Minimum Level
Above Minimum Level
X X
X
X
X X
XX
X
X
*
XxX
X
X
X
1 1 1—I—I I I I
1.0 10.0
Percent Solids
100.0
Figure 7-46. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of PCB-1232
-------
X Minimum Level
A Above Minimum Level
-J
to
1 \J\J\J\J
1000
^^
M
60
1 10°
t_l
a
u
0
a
o
U
10
1
E ' ' r~~1 i " i i | i i — i — i — i i i i | 1 1 — i i — i i i i_
x
x
- x _
X
: x :
- x x x vx x x
X yXv XL xx •>: x
X "^f X "^x X
X x XX xx x >r^^Sc x
X Xvv
X ^
"~
—
X
~
X
- ~
1 1 1 — 1 — 1 — 1 1 1 1 1 1 1 — 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0.1
1.0 10.0
Percent Solids
100.0
Figure 7-47. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of PCB-1242
-------
x Minimum Level
W>
.2
•to*
2
<-•
a
o
u
a
o
U
10000
A Above Minimum Level
1000
100
10
; ' ' ' 1 ' 1 1 1 | 1 1 1 1 1 1 1 1
X
x x ^,
i 1 — i — i — i — i i i.
X >|$${«8$O$&$COX
x *&#$*X(vv^
x xx xX x x
X X Xxv,
XX X* X
t— — i — i — i — i i i i 1 : 1 i .
X
x.
'.
0.1
1.0 10.0
Percent Solids
100.0
Figure 7-48. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of PCB-1242
-------
x Minimum Level A Above Minimum Level
10000
1000
'So
M
\
00
1 100
rt
l-l
•M
a
o
u
a
o
U
10
E~~ ' """ ' ' ' ' ' " | i i i i r i i i | 1 1 1 1 — i | | ,_
A :
X
X
A
r X x
1 x A A A :
xx x #x X XA ^ A :
x *XX xx x*< *xavv x xx £ ^^L^ A A A "
r x x Xx 3*^ -
X XV7
X _
'A
x _
~
X
\ }
— 1 1 1 L_J 1 1 1 1 1 1 1 i ,
l>
o.i i.o 10.0 100.0
Percent Solids
Figure 7-49. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of PCB-1248
-------
x Minimum Level
A Above Minimum Level
~J
I
LA
1 \J\J\J\J
1000
~
60
3
a
0
5 100
M
a
u
o
a
0
U
10
i
: ' ' ' ' ' ' ' ' | i i i i i i i i | i 1 1 — i — i — i i i.
A
-
-
A _
A A
A AA
AA
r A A A
; A :
A x X&OJ896O9C jfct#SC>0«
X \j^8$£-^/V^
ytttMypK^^P^ X ~
fc^jSwIP XxX
X X •Wr^ x
x xx.x^ X X
^5"
— -Jf*. V V V ~
^»^y ^AO
xS /V /\ x\ ^* ^
X XX xX X
x x xx"x.
xx xx x
1 1 — 1 — 1 — 1 1 1 1 1 1 III 1 1 I 1 1
'
k
j. •'•• • • • — 1 1 1 1 — i — i — i — i_j
01 1.0 10.0 100.0
Percent Solids
Figure 7-50. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of PCB-1248
-------
.*>.
ON
60
M
60
«
o
«
o
o
a
o
U
10000
1000
100
10
o.i
x Minimum Level
A Above Minimum Level
x
x
X
x x
x
1 - 1 - 1 — 1 — 1 — 1 I 1
xx
X
1.0 10.0
Percent Solids
x
8:
100.0
Figure 7-51. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of PCB-1254
-------
10000
1000
60
a
1 100
M
•«->
a
u
u
a
0
U
10
1
0.
x Minimum Level A Above Minimum Level
; ' ' ' 1 I~T ' l | 1 1 1 1 1 1 1 1 | | | ' — T 1 1 1 1 |_
A
: * ~
; A AA ^
A
- X -
X x J£Xx X x
XV X
t^S
S^&{_s v.O> ^ '^
X ^A/3t>^\ X
XXX VX X^<^< X
X XXxX X
X Xxxv.,
xx xX x
1 1 L_ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 | | | I | | | | .
1 1.0 10.0 100.0
Percent Solids
Figure 7-52. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of PCB-1254
-------
\
a
.2
•4->
§
a
u
u
a
o
U
10000
1000
100
10
o.i
x Minimum Level
A Above Minimum Level
X
X
x
X
X
x
x
x
x
XX
X
X
X
1.0 10.0
Percent Solids
100.0
Figure 7-53. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of PCB-1260
-------
x Minimum Level
A Above Minimum Level
AUUUU
1000
60
o
^o
g 100
a
o
o
a
o
U
10
1
0.
i ' ' 1 ' ' ' ' ' | ' i 1 — i — i i i i | 1 1 1 — i — i i i i.
; A I
A AA AA
A A
f A A -
^fc\&K&F§ ^^Y^
— O»*Wk i
vv vx ^»*. \S •*
X. X N?^
x $ x* X x
X o>x'o<
- * ^*$£ X^ X
V N/ '^^ \/ ~
x x x ^ x
1 1 1 — 1 — 1 — 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
h
1 1.0 10.0 100.0
Percent Solids
Figure 7-54. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of PCB-1260
-------
~J
o
100.00
10.00
'oi
M
W>
J
1 1.00
2
a
u
u
a
0
U
0.10
0.01
0.
x Minimum Level A Above Minimum Level
E ' ' ' ' i i i i | i i i i i i i : | T 1 [— i — i i i i.
X
X A A
X * A*AAAAAXAA*
- X A A* A A A £ _
: AX^4A^A / A A AA*A^^^^\A| AA
,. Ax ****>* f A A^ ^A A^^
X A A^ X AA .
x x •CAA A
E x A A 1
X
X
1 1 1 1 1 1 1 1 1 1 1 1
L
1 1.0 10.0 100.0
Percent Solids
Figure 7-55. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of SELENIUM
-------
100.00
X Minimum Level
Above Minimum Level
i—i—i i i 1
1 1 1—I—I—I I l_l
60
J
a
o
a
o
u
O
O
U
10.00
1.00
0.10
0.01
0.1
X X
X X X
X
_L
X X
X
X
X
_L
1.0 10.0
Percent Solids
AA
100.0
Figure 7-56. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of SELENIUM
-------
x Minimum Level
Above Minimum Level
1 \J\J\J\J\J
10000
"M
M
""S^
bo
£j
•^•^
rt
% 1000
c1
«
o
o
a
o
U
100
1 0
E r~ ' ' ' ' ' ' ' | ' ' i i — i — iii| 1 1 1 1 — i — rr-r:
- X
: x ~
x
X
x
y X X \/
X X v X
X v*^\/ '^6' vX sX X
X 'v' x ^^s X
- x^x^ ^x*^^^^,^ x xxxx^xx^l||iN&k>%*<
v X \/ v v /^^ /^^^*S*'^^^Lt'
- XX XA ^ ^ y V'^^^^' v
Xy ,«&
^Vtf^V'
X Xv
X ^
"
X
- _
: x :
1 1 1 1 1 1 LJ 1 1 1 I
i \j • • — • — • —
0.1 1.0 10.0 100.0
Percent Solids
Figure 7-57. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of TOXAPHENE
-------
~J
Ul
100000
a
o
a
o
t>
a
o
O
10000
1000
100
10
0.1
x Minimum Level
XX
1 - 1
Above Minimum Level
X
x
X
x
X. i i X
X
X
-X—1 1 1 I I I 1 I I
-I 1_
1.0 10.0
Percent Solids
100.0
Figure 7-58. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of TOXAPHENE
-------
x Minimum Level
Above Minimum Level
1 \JV\J \J\J.\J
10000.0
3 i 000.0
W>
1 1 00.0
rt
a
u
u
5 100
1.0
0.1
0
E i i i i i i i i | i i 1 1 — i — i i i | 1 1 1 1 — i — 1||.
X X I
=- x x _
X x E
; x x x x x< :
x x A _
— XX X x X A A
- x xxxxx>xX x x x x :
vS^te Vy X v X N^C* v v v
"^"t^ vt/ '^ \XL>v 'X^
XxvvX< XXX
/\ A ^ v
\x A
: x^T*x ^ ^ ;
r A ^1
i i i i i i i i 1 i i i i i i i i 1 i i i i i i i i
1 1.0 10.0 100.0
Percent Solids
Figure 7-59. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of TRICHLOROETHENE
-------
x Minimum Level
A Above Minimum Level
I \t\JV\J\J.\J
10000.0
-
^ 1000.0
3
a
1 100.0
a
0
0
6 10.0
1.0
0.1
0.
E ' ' "> ' i i i i | I —1 1 1 — 1 1 1 1 | : 1 1 1 1 I I i |-
- X _
X
X
r x x x *
: A :
x A x A x
X X X;jX
: x ^ x x x x xx x\
*x x x x x x
I x X xx xx^ E
A. \x
X^
1 1 1 — i — i — iiil i i i i i i i i 1 i i i i i i i i i
1 1.0 10.0 100.0
Percent Solids
Figure 7-60. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of TRICHLOROETHENE
-------
x Minimum Level
Above Minimum Level
1 \J\J\J\J\J.\J
10000.0
3 1000.0
j?
1 1 00.0
rt
a
o
I 10.0
1.0
0.1
0.
= r ' ' ' i ' ' ' | ' i i i T — i i i | — — r 1 1 — i — i — i i i-
- A :
- AA _!
- A —
] A A AA i A4 ^ =
A A A A m AA AJ^ AA
f AA AAAA\^^-^l ^^A^W^^A
^^ A A A ~
r A A
I A :
i i i i i i i i 1 i i i i i i i i 1 i i ,
k
1 1.0 10.0 100.0
Percent Solids
Figure 7-61. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of ZINC
-------
x Minimum Level
Above Minimum Level
•~J
-J
CO
a
Q
a
o
o
a
o
u
100000.0
10000.0
1000.0
100.0
10.0
1.0
0.1
0.1
A A
A A
~T 1 1 1 1—I I I-|
1
1.0 10.0
Percent Solids
100.0
Figure 7-62. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of ZINC
-------
x Minimum Level
Above Minimum Level
1 UUU.U
100.0
la
M
\
3
1 10.0
rt
IH
a
u
u
a
0
U
1.0
0.1
0.
x
: A :
X
X
X
- xxxxxx
" xxx x Xx ^
*y^
: x :
x
i i i i i i i i i i i i i i i i ! i i i i i i i i
1 1.0 10.0 100.0
Percent Solids
Figure 7-63. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of 4,4 -DDD
-------
x Minimum Level
Above Minimum Level
1UUU.U
100.0
f—4
M
a
o
2 i o.o
IH
a
o
o
a
o
U
1.0
0 1
_ ~
: A :
_
-
Y-
X 5-x^ ^SKP^^^^^^*"^
- x &$j$*>% X\ '^ A,
1 1 1 i 1 1 1 1 1 1 1 1 1 1 1 III , , , , , , , ,
\ff 1 — . •— — ' ' • — 1— '
0.1 1.0 10.0 100.0
Percent Solids
Figure 7-64. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of 4.4 -DDD
-------
x Minimum Level
Above Minimum Level
-J
I
o
1UUU.U
100.0
•*bfl
^
DO
v~*'
a
3 1 0.0
rt
4->
a
u
u
a
o
U
1.0
m
E ' ' ' ' ' ' ' ' | i r i i — i — i i i | -i 1 1 ; — i — i i i_
~ X
X
X
X .
X
A
- X X x ,vx X x
X N^y* sit' X "^ X -
X p^ -vV" X ^X X \x •v'
>^/*^ sX v ** '^ v ^^^ ' ^ X ^X v j?>X^aa^jsAi: i *
>x^^^v' ^S* ^Sc^ X x X>^v^ v'/^J^^BS^&^'^S^,^,-
X xxx xX x >^^H^
X Xy ^B
"^^
— _
: x :
~
x
"
-
~
1 1 1 — i — i — i i i 1 i i i i i i i i 1 i
0.1
1.0 10.0
Percent Solids
100.0
Figure 1-65. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of 4.4 -DDE
-------
x Minimum Level
A Above Minimum Level
1UUU.U
100.0
M
3
a
1 1 0.0
a
o
o
a
o
U
1.0
0.1
0.
: ' ' | ' i 1 — | 1 1 1 —
~ A _
A
L -^^C*0^
X"«>^X v -
X x^
"~ x^ X X
x $ x>< X x
: x x ^^& x :
1 1 1 1 1— L--I 1 1 1 1 I 1 1 1 1 1 1 ,
1 10 10.0 100.0
Percent Solids
Figure 7-66. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of 4.4 -DDE
-------
1000.0
x Minimum Level
Above Minimum Level
--J
>-—
to
M
M
rt
o
a
o
o
a
o
U
100.0
10.0
1.0
X
x
X
x
*
v v
X
X
X
0.1
0.1
1.0 10.0
Percent Solids
100.0
Figure 7-67. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of 4.4 -DDT
-------
x Minimum Level
A Above Minimum Level
J.UVSU.U
100.0
M
3
a
1 1 0.0
IH
a
o
0
ft
0
O
1.0
0.1
0.
; ' ' ' ' ' ' ' ' | ~ i " i i — i i i i | 1 1 1 1 — i i i i.
I
A A _
X ^ ^ X
f A xXA ^ X x -
X v f w^6?9> y
v v \x X *^fx5vv
XN \xV X
XV X^X V
X\ ^
1 1 1 1 — i — i i i 1 i i i i .1 i i i | | i i i i i i i
1 1.0 10.0 100.0
Percent Solids
Figure 7-68. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of 4.4 -DDT
-------
100000
e*
M
^
tat
a
o
'<->
2
-M
a
u
u
a
o
U
10000
1000
100
10
0.1
x Minimum Level
A Above Minimum Level
i—i—i i i
A A AAA
A
A
A
**A
AA
-1 1 1 I I I I I
-1 I
1.0 10.0
Percent Solids
100.0
Figure 7-69. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of PHOSPHORUS
-------
Y>
Os
100000
60
J
a
.3
a
o
u
a
o
U
10000
1000
100
10
x Minimum Level
—i 1—i—i—i i i i—
Above Minimum Level
1 — III
A -
A A A A
\ A A
-1 1 1—I I I I 1
0.1
1.0 10.0
Percent Solids
100.0
Figure 7-70. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of PHOSPHORUS
-------
1000000
100000
60
CO
l-i
•M
a
u
u
a
o
U
10000
1000
100
10
0.1
x Minimum Level
A Above Minimum Level
~i 1 1 1—i—I
A A
-J 1—_l I I I I I
-1 1 1 I I L_l_
1.0 10.0
Percent Solids
100.0
Figure 7-71. Percent Solids of NSSS Samples Versus
DRY WEIGHT Concentrations of TOTAL KJELDAHL NITROGEN
-------
x Minimum Level
60
J
a
.2
-M
2
•M
a
o
o
a
o
u
1000000
100000
10000
1000
100
10
0.1
_L_L
1
A Above Minimum Level
1 1—i—i—i i i i
T 1 1 1—i—i—nq
1.0 10.0
Percent Solids
100.0
Figure 7-72. Percent Solids of NSSS Samples Versus
WET WEIGHT Concentrations of TOTAL KJELDAHL NITROGEN
-------
1000.0
ON
oo
\
oo
a
o
u
o
a
o
U
100.0
10.0
.u
0.1
I I I I I M I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I II I I I I I I I I I I I I I I I I U
Detection Rate: 3%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-73. Cumulative Distribution Functions: ALDRIN
-------
1000.0
~J
VO
J
a
o
o
a
o
O
100.0 r
10.0 -
1.0 r.f
0.1
I" "MI i i|i 11 n 111111111111111111111 n 111111 u 1111111 M 1111111111111
Detection Rate: 80*
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
Nonparametric with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-74. Cumulative Distribution Functions: ARSENIC
-------
-J
I
o
100000.0
10000.0
M
M
60
rt
o
a
u
o
a
o
U
1000.0
100.0
10.0
1.0
[ I ' I I I I 1 1 I I I I I I I I I I I I I I I I I I I I I M I I I I I I I I I I II I I II I I I I I I I I I I I I I I I I I I I I M I I I I
Detection Rate: 0*
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multiccnsored lognormal nonestimable
Q | I I I I I I I I I I I I I I I I I I I 1 I I I I I I I I I I I I I 1 I I I I I I I II I I I I I I I < 1 I I I I I I I I M I I I I I I I I I I I
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-75. Cumulative Distribution Functions: BENZENE
-------
1000000.0
-4
>—*
-J
100000.0 -
_ 10000.0 r
M
00
ft
o
a
o
u
a
o
U
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-76. Cumulative Distribution Functions: BENZO(A)PYRENE
-------
100.0
•~4
(O
BO
M
M
2
o
a
o
U
10.0
1.0
I ' i I i i I I i i i i i i i i i i I I i i i i 11 i i i i i i i i pn | i i i 11 i i i i | i i i i i i i i i | i
Detection Rate: 2296
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
0.1
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-77. Cumulative Distribution Functions: BERYLLIUM
-------
1000000.0
100000.0
_ 10000.0
I" 11| 11111111 i|ii i 11111111111111111111111111 M 11111 1111 11111 n 1111111
Detection Rate: 63%
Key: x Multicensored lognormal
O Nonparametric with ML set to zero
Nonparametric with ML set to ML
~ 1000.0
a 100.0
O
o
a
o
u 10.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-78. Cumulative Distribution Functions: BIS(2-ETHYLHEXYL) PHTHALATE
-------
10000.0
1000.0
60
60
S 100.0
a
o
•M
ed
\->
•M
a
o
o
a
o
U
10.0 r
1.0
0.1
111111111111111111111111111111111 111111III
Detection Rate: 69%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
Nonparametric with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-79. Cumulative Distribution Functions: CADMIUM
-------
1000.0
oo
M
00
a
o
o
a
o
U
100.0
10.0
1.0
A 1
I' """ " [in HIM i [inn ii iij MIIII i ii|i i ii i ii 111 ii inn i i|n
Detection Rate: 69%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-80. Cumulative Distribution Functions: CADMIUM*
* Excluding an Extreme Outlier Observation From Stratum 3
-------
-jj
Cj
10000.0
1000.0
60
M
at
It
*J
a
u
u
a
o
U
100.0
10.0
1.0
0.1
" " ' 111" 11111111II1111111111111111111111111111111 11111111111111 11111111111_
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-81. Cumulative Distribution Functions: CHLORDANE
-------
-jj
>—»
~J
10000.0
1000.0
BO
J4
to
a
o
o
a
o
U
100.0
10.0
1.0
'I " " ('"" " ' '[" " "I I I I I III II I I I I I I I) I I || I [HI I I II I I | II I II II I I | I I I I I II I I | I I
Detection Rate: 91%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
0.1
r i
c
(
(
1 1 1 1 1 1 1 1 y
—
•
.
HI II 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 i i i i i i i i i 1 iinln 1 i i i i i i i i i 1
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-82. Cumulative Distribution Functions: CHROMIUM
-------
10000.0
1000.0
M
00
J
a
o
• *4
<=»
a
w
4-1
a
o
o
a
o
U
100.0
iO.O
''"''' I " " I " 111111111111111II1111111111111111111 III 111 II
Detection Rate: 100%
Key: x Multicensored lognormal
O Nonparametric with ML set to zero
A Nonparametric with ML set to ML
Q I I I I I I I I I I I I I I I I I I I I I I 111 1 I I I I I I I I I I I I I I I I I I I I I 1 | I ll I I I II I I I I I I I I II II I I I I I I I 1 I
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-83. Cumulative Distribution Functions: COPPER
-------
1000.0
00
a
o
o
u
u
a
o
U
100.0
10.0
1.0
0.1
'I I '["MI ini| i mi mi |i 11 n 111111111 ii i ii i ii 1111111| 111111
Detection Rate: 5%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-84. Cumulative Distribution Functions: DIELDRIN
-------
oo
o
60
a
o
o
a
o
O
1000.0
100.0
10.0
1.0
0
I ' T 'I I I n 1 I I I I I I I I I I [ I I I I I I I I I I I I H I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I [,
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-85. Cumulative Distribution Functions: HEPTACHLOR
-------
oo
1000000.0
100000.0
_ 10000.0
60
M
60
~ 1000.0
a
o
a
u
u
a
o
u
100.0
10.0 -
1.0
11111111111111111111111111111111111 1111II111111111111111 II
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
_ J 1111 nun Inn 11 u 111111111 n 1111 In l.n n i... I I,
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-86. Cumulative Distribution Functions: HEXACHLOROBENZENE
-------
00
(O
1000000.0
100000.0
M
60
J3
a
o
u
u
a
o
U
10000.0
1000.0
100.0
10.0
1.0
' " ' I I I I ' I I ' I H I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I || I I I I I I I I I || I I I I I
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
01 I I I I I I I I I I I I I I I I I I I I I I I I I I I l l l I l l l ll l i i i i i i i I ml null
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-87. Cumulative Distribution Functions: HEXACHLOROBUTADIENE
-------
-4
H—
oo
00
M
eo
J
a
o
a
o
o
a
o
U
10000.0
1000.0
100.0
10.0
1.0
0.1
' I " 'I "I
Detection Rate: 80%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
i >
<)
o
ilnn I
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-88. Cumulative Distribution Functions: LEAD
-------
-J
00
1000.0
00
a
o
o
a
o
U
100.0
10.0
1.0
111111111 11111 I '!11111111111111 1111111111 11111 1111111 11111111111 I 11
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
01 I I I I I I I I I I I I I I I I I I I I I I | | I I I I I I I I I I I I II Ill I I 1 I I I I I I I I I I I I | , I I
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-89. Cumulative Distribution Functions: LINDANE (GAMMA-BHC)
-------
1000.0
-jj
oo
eo
.*
BO
J
a
o
a
o
o
a
o
U
100.0
10.0
1.0
0.1
1 I ""'"H I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I l[ I I I II I I I 1(1 I I II I I I 1) I I I I I I I I I I I I I I I I I I
Detection Rate: 64%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonpatametiic with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-90. Cumulative Distribution Functions: MERCURY
-------
1000.0
oo
o\
06
a
.2
2
<->
a
u
O
rt
O
U
100.0
10.0
i rv
l.\J
0.1
' 'I "I I I I I II I I I I I I I I I I I I I I I I I I I I II I I I I I I I I I I M I I I I I I I I I I I Lj
Detection Rate: 53*
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-91. Cumulative Distribution Functions: MOLYBDENUM
-------
-J
I
oo
1000000.0
100000.0
60
J*
00
1 10000.0
2
4-1
a
4)
O
a
o
O
1000.0
100.0
" ' " " I r" " I " " " ' 111" ' 111111111111111111111111111111111111111111111 M 111111
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
I i^ j
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-92. Cumulative Distribution Functions: N-NITROSODIMETHYLAMINE
-------
10000.0
CXI
00
1000.0
00
M
BO
J
a
o
a
o
u
a
o
U
100.0
10.0
' 11IIIIIII11 1111111111111111111111111111111111111111111111111111111111
Detection Rate: 67%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
0.1
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-93. Cumulative Distribution Functions. NICKEL
-------
~J
oo
10000.0
1000.0
bo
M
60
a
o
o
a
o
O
100.0
10.0
1.0
11 'I "" I'" n 1111111111111111
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored iognormal nonestimable
I I I I I I I I I I LI
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-94. Cumulative Distribution Functions: PCB-1016
-------
-jj
h—i
O
10000.0
1000.0
M
M
rt
o
a
o
o
a
o
U
100.0
10.0
1.0
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-95. Cumulative Distribution Functions: PCB-1221
-------
10000.0
bo
M
00
3
a
o
•r*
*•
2
0
a
o
U
1000.0
100.0
10.0
1.0
I '" ""l I I I I I ' I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I II I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I L
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-96. Cumulative Distribution Functions: PCB-1232
-------
--J
K)
10000.0
oO
M
00
a
o
•F-l
1-1
at
»H
•4-1
a
o
o
a
o
U
1000.0
100.0
10.0
1.0
1' " I "" '' I " ' " " '' I " ''''''' I " 1II1111111111111111111II11111111111111 I
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-97. Cumulative Distribution Functions: PCB-1242
-------
100000.0
10000.0 -
bo
J4
t>0
a
o
a
41
O
a
o
U
1000.0
100.0
I ''" r * i
Detection Rate: 9%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
Nonparametric with ML set to ML
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-98. Cumulative Distribution Functions: PCB-1248
-------
1000000.0
100000.0
_ 10000.0
66
M
a
o
a
o
a
a
o
O
1000.0 r
Detection Rate: 9*
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
Nonparametric with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-99. Cumulative Distribution Functions: PCB-1254
-------
100000.0
10000.0
60
M
60
3
a
o
a
o
o
a
o
1000.0
100.0
I " "" " 'I' "" " " I '" I "" 11111111111111111111111111II1111111111111111 n 11111111
Detection Rate: 10%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
Nonparametric with ML set to ML
0.1
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-100. Cumulative Distribution Functions: PCB-1260
-------
100.0
DO
M
a
o
<->
s
4-»
a
o
u
a
o
U
10.0
1.0
0.
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ..... 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ..... MI
Detection Rate: 68%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-101. Cumulative Distribution Functions: SELENIUM
-------
-^
-J
100000.0
10000.0 -
M
M
00
a
o
3 1000.0
a>
o
a
o
U
100.0
10.0
I1 IIIHTII|II mini 1111111111 j 11 ii mi 11 ii i n 11111 ii 11111111111 n 111
Detection Rate: 0%
Key: O Nonparametric with Minimum Level (ML) set to zero
Nonparametric with ML set to ML
Multicensored lognormal nonestimable
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-102. Cumulative Distribution Functions: TOXAPHENE
-------
100000.0
10000.0
60
M
§ 1000.0
a
100.0
a
o
U
10,0
1.0
I 1111111 111 " 11'" I " 11 [111111111111111II1111111111111111111111111111111 li
Detection Rate: 1%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-103. Cumulative Distribution Functions: TRICHLOROETHENE
-------
100000.0
-J
VO
10000.0
bft
M
bo
J
a
.2
1->
s
4-1
a
o
u
a
o
U
1000.0 r-
100.0
I" |""""'|'"IIIIH|IIIIIIIII|IIII||||||IIIIIIIII|IIIIIIIII|IIHIIIH|IIIIIIH
Detection Rate: 100%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
Nonparametric with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-104. Cumulative Distribution Functions: ZINC
-------
60
M
\
60
El
O
n
O
u
a
o
U
1000.0
100.0
10.0
i.o
"" 1111111 11 1111111111111111111111111111111111 11111111111111111111111
Detection Rate: Ofc
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
Q \ I I I I I I I I I I 111 I I I I I I I I I I I I I I I I I I I I I I l l 11 ii I i i l l i n i i I i I , | , | | I,,
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
"-II
H 1
H )
i )
i.o
Figure 7-105. Cumulative Distribution Functions: 4.4-ODD
-------
1000.0
M
M
60
3
a
o
a
o
o
a
o
U
100.0
10.0
1.0
'I 'I" "I1" I "
Detection Rate: 1%
Key: O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
Multicensored lognormal nonestimable
J llMI III! I I I Illll I II 111 I I I II I! I. Illm I II! I I I I I I . II II I I Hill!
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Fraction of POTW Values Less Than Concentration
1.0
Figure 7-106. Cumulative Distribution Functions: 4.4-DDE
-------
to
o
to
100000.0
10000.0
t*
M
60
3
a
o
a
u
o
a
o
U
1000.0
100.0
10.0
1.0
0.1
"'""I"1"""!111 1
Detection Rate: 2%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-107. Cumulative Distribution Functions: 4.4-DDT
-------
K)
O
1000000.0
100000.0
~ 10000.0
M
3 1000.0
a
£
'•<->
g
a
o
u
a
o
u
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I l[ I I I I I I I I I I I I I I I I I
Detection Rate: 100%
Key: x Multicensored lognorroal
O Nonparametric with Minimum Level (ML) set to zero
Nonparametric with ML set to ML
Q 1 * i Inn 111 nl I mi i nn 11 HIM i n I 11
100.0
10.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-108. Cumulative Distribution Functions: PHOSPHORUS
-------
1000000.0
100000.0
M
60
10000.0
2
u
O
u
O
a
O
u
1 000.0
I' " " " " I 111111111111111 1111111111111 11 I 11111 I
Detection Rate: 100%
Key: x Multicensored lognormal
O Nonparametric with Minimum Level (ML) set to zero
A Nonparametric with ML set to ML
1 00.0 ' ' ' ' ' ' ' ' ^ M I I I I I I I I I I I I I I II I I I I I I I I ! I I, I I I I I I I I llMIMmluilMMlLni.il
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-109. Cumulative Distribution Functions: TOTAL KJELDAHL NITROGEN
-------
to
8
1000.0
a
o
a
o
o
a
o
U
100.0
S 10.0
1.0
0.1
pll U I III) I I I I II I 11)11 III II M I I I I I I I I I I I I I I I I i i i
Detection Rate: 100%
Key: x Multicensored lognortnal
O Nonparametric with Minimum Level (ML) set to zero
Nonparametric with ML set to ML
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Fraction of POTW Values Less Than Concentration
Figure 7-110. Cumulative Distribution Functions: PERCENT SOLIDS
-------
REFERENCES
Volume I and Volume II
Agresti, Alan. 1984. Analysis of Ordinal Categorical Data. John Wiley & Sons, Inc.,
New York, NY.
Aitchison, J., and J.A.C. Brown. 1963. The Lognormal Distribution. Cambridge University Press,
New York, NY.
Barakat, Richard. 1976. "Sums of Independent Lognormally Distributed Random Variables."
Journal of the Optical Society of America. Vol. 66, No. 3 (March).
Cochran, W.G. 1977. Sampling Techniques. Third edition. John Wiley & Sons, Inc.,
New York, NY.
Cohen, A. Clifford, Jr. 1959. "Simplified Estimators for the Normal Distribution When Samples
are Singly Censored or Truncated." Technometrics. Vol. 1, No. 3 (August).
Everitt, B.S. 1977. The Analysis of Contingency Tables. John Wiley & Sons, Inc., New York, NY.
Gilliom, Robert J. and D.R. Helsel. 1986. "Estimation of Distributional Parameters for Censored
Trace Level Water Quality Data. 1. Estimation Techniques." Water Resources Research.
Vol. 22, No. 2 (February).
Hansen, M.H., W.N. Hurwitz, and W.G. Madow. 1953. Sample Survey Method and Theory
Volume II: Theory. John Wiley & Sons, Inc., New York, NY.
Helsel, D.R. and T.A. Cohn. 1988. "Estimation of Descriptive Statistics from Multi-Censored
Water Quality Data." Water Resources Research. Vol. 24, No. 12. (December).
Helsel, D.R., and R.J. Gilliom. 1986. "Estimation of Distributional Parameters for Censored Trace
Level Water Quality Data. 2. Verification and Applications." Water Resources Research.
Vol. 22, No. 2 (February).
Helsel, Dennis. 1990. "Less than Obvious: Statistical Treatment of Data Below the Detection
Limit." Environmental Science Technology. Vol. 24, No. 12.
Hollander, Myles, and D.A. Wolfe. 1973. Nonparametric Statistical Methods. John Wiley & Sons,
Inc., New York, NY.
U.S. Environmental Protection Agency. 1988. "Supporting Statement for the National Sewage
Sludge Survey." (August).
U.S. Environmental Protection Agency. 1989A. "Standards for the Disposal of Sewage Sludge;
Proposed Rule (40 CFR, Parts 257 and 503)." (February).
R-l
-------
REFERENCES
Volume I and Volume II (continued)
U.S. Environmental Protection Agency. 1990. "National Sewage Sludge Survey; Availability of
Information and Data, and Anticipated Impacts on Proposed Regulations; Proposed Rule (40
CFR Part 503)." (November).U.S. Environmental Protection Agency. 1990. Technical Support
Documentation for Part 1 of the National Sewage Sludge Survey Notice of Availability.
(October).
U.S. Environmental Protection Agency, Industrial Technology Division, Office of Water Regulations
and Standards. 1989B. "Analytical Methods for the National Sewage Sludge Survey."
U.S. Environmental Protection Agency, Office of Water. 1990. Analytical Methods for the National
Sewage Sludge Survey. (September).
U.S. Environmental Protection Agency, Office of Water Program Operation, EPA-430/9-78-001.
1978. Field Manual for Performance Evaluation and Troubleshooting at Municipal
Wastewater Treatment Facilities.
R-2
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