United States
Environmental Protection
Agency
Office of Water
(4303)
EPA 821-B-97-009
January 1998
Environmental
Assessment of Proposed
Effluent Limitations
Guidelines and Standards
for Industrial Waste
Combustors
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AL ASSESSMENT! OF
aDusimiAL WASTEE COMBOSTOES
Prepared Jfor:
Office of Scfeace and Tedinologjr
Standards and Applied ^Science DMsaoa
- ^OlM Street, S;W. „ - '
' Washington, D.C, 2046S , ' %%
Patricia Hanigan ..
Task Manager _
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ACKNOWLEDGMENTS AND DISCLAIMER
This report has been reviewed and approved for publication by the Standards and Applied
Science Division, Office of Science and Technology. This report was prepared, with the support
of Versar, Inc. (Contract 7W-3300-NASA) under the direction and review of the Office of
Science and Technology. Neither the United States Government nor any of its employees,
contractors, subcontractors, or their employees make any warranty, expressed or implied, or
assumes any legal liability or responsibility for any third party's use of or the results of such use
of any information, apparatus, product, or process discussed in this report, or represents that its
use by such party would not infringe on privately owned rights.
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TABLE OF CONTENTS
Page, Nh
EXECUTIVE SUMMARY vi
1. INTRODUCTION . . i
2. METHODOLOGY 3
2.1 Projected Water Quality Impacts 3
2.1.1 Comparison of Instream Concentrations with Ambient Water
Quality Criteria 3
2.1.1.1 Direct Discharging Facilities 4
2.1.1.2 Indirect Discharging Facilities 7
2.1.1.3 Assumptions and Caveats 10
2.1.2 Estimation of Human Health Risks and Benefits 12
2.1.2.1 Fish Tissue .12
2.1.2.2 Drinking Water 15
2.1.2.3 Assumptions and Caveats 16
2.1.3 Estimation of Ecological Benefits 17
2.1.3.1 Assumptions and Caveats 19
2.1.4 Estimation of Economic Productivity Benefits 20
2.1.4.1 Assumptions and Caveats 21
2.2 Pollutant Fate and Toxicity 22
2.2.1 Pollutants of Concern Identification 22
2.2.2 Compilation of Physical-Chemical and Toxicity Data 23
2,2.3 Categorization Assessment 27
2.2.4 Assumptions and Limitations 31
2.3 Documented Environmental Impacts 32
3. DATA SOURCES 33
3.1 Water Quality Impacts .33
3.1.1 Facility-Specific Data 33
3.1.2 Information Used to Evaluate POTW Operations 34
3.1.3 Water Quality Criteria (WQC) . . . 35
3.1.3.1 AquaticLife 35
3.1.3.2 Human Health 36
3.1.4 Information Used to Evaluate Human Health Risks and Benefits ... 40
3.1.5 Information Used to Evaluate Ecological Benefits . 40
3.1.6 Information Used to Evaluate Economic Productivity Benefits ....41
3.2 Pollutant Fate and Toxicity 42
3.3 Documented Environmental Impacts 42
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TABLE OF CONTENTS (Continued)
Page No.
4. SUMMARY OF RESULTS 43
4.1 Projected Water Quality Impacts 43
4.1.1 Comparison of Instream Concentrations with Ambient Water
Quality Criteria 43
4.1.1.1 Direct Discharges 43
4.1.1.2 Indirect Discharges 44
4.1.2 Estimation of Human Health Risks and Benefits 45
4.1.2.1 Direct Discharges 45
4.1.2.2 Indirect Discharges 47
4.1.3 Estimation of Ecological Benefits 48
4.1.3.1 Direct Discharges 48
4.1.3.2 Indirect Discharges 49
4.1.2.3 Additional Ecological Benefits 49
4.1.4 Estimation of Economic Productivity Benefits . . 50
4.2 Pollutant Fate and Toxicity 50
4.3 Documented Environmental Impacts 51
5. REFERENCES R-l
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VOLUME H
Page Nn
Appendix A IWC Facility-Specific Data . A-l
Appendix B National Oceanic and Atmospheric Administration's (NOAA)
Dissolved Concentration Potentials (DCPs) B-l
Appendix C Water Quality Analysis Data Parameters C-l
Appendix D Risks and Benefits Analysis Information D-l
Appendix E Direct Discharger Analysis at Current (Baseline) and
Proposed BAT Treatment Levels . E-l
Appendix F Indirect Discharger Analysis of Current (Baseline) and
Proposed Pretreatment Levels . F-l
Appendix G POTW Analysis at Current (Baseline) and
Proposed Pretreatment Levels G-l
Appendix H Direct Discharger Risks and Benefits Analyses at Current (Baseline)
and Proposed BAT Treatment Levels . . H-l
Appendix I Indirect Discharger Risks and Benefits Analyses at Current (Baseline)
and Proposed Pretreatment Levels 1-1
111
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LIST OF TABLES
Page Nh.
Table 1. Evaluated Pollutants of Concern Discharged from 8 Direct and 3 Indirect
IWC Facilities 52
Table 2 Summary of Pollutant Loadings for Direct and Indirect IWC Facilities 53
Table 3 Summary of Projected Criteria Excursions for Direct IWC Dischargers 54
Table 4 Summary of Pollutants Projected to Exceed Criteria for Direct IWC
Dischargers 55
Table 5 Summary of Projected Criteria Excursions for Indirect IWC Dischargers .... 56
Table 6 Summary of Pollutants Projected to Exceed Criteria for Indirect IWC
Dischargers 57
Table 7 Summary of Projected POTW Inhibition and Sludge Contamination Problems
from Indirect IWC Dischargers : 58
Table 8 Summary of Pollutants from Indirect IWC Dischargers Projected to Cause
POTW Inhibition and Sludge Contamination Problems 59
Table 9 Summary of Potential Human Health Impacts for Direct IWC Dischargers
(Fish Tissue Consumption) 60
Table 10 Summary of Pollutants Projected to Cause Human Health Impacts for
Direct IWC Dischargers (Fish Tissue Consumption) 61
Table 11 Summary of Potential Systemic Human Health Impacts for Direct
IWC Dischargers (Fish Tissue and Drinking Water Consumption) 62
Table 12 Summary of Potential Human Health Impacts for Direct IWC Dischargers
(Drinking Water Consumption) 63
Table 13 Summary of Potential Human Health Impacts for Indirect IWC Dischargers
(Fish Tissue Consumption) 64
IV
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LIST OF TABLES (continued)
Pagp. Nn,
Table 14 Summary of Pollutants Projected to Cause Human Health Impacts
for Indirect IWC Dischargers (Fish Tissue Consumption) 65
Table 15 Summary of Potential Systemic Human Health Impacts for Indirect
IWC Dischargers (Fish Tissue and Drinking Water Consumption) 66
Table 16 Summary of Potential Human Health Impacts for Indirect IWC
Dischargers (Drinking Water Consumption) . 67
Table 17 Summary of Ecological (Recreational) Benefits for Indirect IWC Dischargers . 68
Table 18 Cost Savings from Shifts in Sludge Use or Disposal Practices from
Composite Baseline Disposal Practices 69
Table 19 Potential Fate and Toxicity of Pollutants of Concern 70
Table 20 Toxicants Exhibiting Systemic and Other Adverse Effects 71
Table 21 Human Carcinogens Evaluated, Weight-of-Evidence Classifications,
and Target Organs 72
Table 22 IWCs Included on State 304(1) Short Lists 73
Table 23 POTWs Which Receive Discharge from IWCs and are Included
on State 304(1) Short Lists 74
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EXECUTIVE SUMMARY
This environmental assessment quantifies the water quality-related benefits associated with
achievement of the proposed BAT (Best Available Technology) and PSES (Pretreatment Standards
for Existing Sources) controls for commercial industrial waste combustors (IWCs). Based on site-
specific analyses of current conditions and changes in discharges associated with the proposal, the
U.S. Environmental Protection Agency (EPA) estimated instream pollutant concentrations for 17
priority and nonconventional pollutants from direct and indirect discharges using stream dilution
modeling. The potential impacts and benefits to aquatic life are projected by comparing the
modeled instream pollutant concentrations to published EPA aquatic life criteria guidance or to
toxic effect levels. Potential adverse human health effects and benefits are projected by: (1)
comparing estimated instream concentrations to health-based water quality toxic effect levels or
criteria; and (2) estimating the potential reduction of carcinogenic risk and noncarcinogenic hazard
(systemic) from consuming contaminated fish or drinking water. Upper-bound individual cancer
risks, population risks, and systemic hazards are estimated using modeled instream pollutant
concentrations and standard EPA assumptions. Modeled pollutant concentrations in fish and
drinking water are used to estimate cancer risk and systemic hazards among the general
population, sport anglers and their families, and subsistence anglers and their families. EPA used
the findings from the analyses of reduced occurrence of instream pollutant concentrations in excess
of both aquatic life and human health criteria or toxic effect levels to assess improvements in
recreational fishing habitats that are impacted by IWC wastewater discharges (ecological benefits).
These improvements in aquatic habitats are then expected to improve the quality and value of
recreational fishing opportunities.
Potential inhibition of operations at publicly owned treatment works (POTW) and sewage
sludge contamination (here defined as a sludge concentration in excess of that permitting land
application or surface disposal of sewage sludge) are also evaluated based on current and proposed
pretreatment levels. Inhibition of POTW operations is estimated by comparing modeled POTW
influent concentrations to available inhibition levels. Contamination of sewage sludge is estimated
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by comparing projected pollutant concentrations in sewage sludge to available EPA regulatory
standards for land application and surface disposal of sewage sludge. Economic productivity
benefits are estimated on the basis of the incremental quantity of sludge that, as a result of reduced
pollutant discharges to POTWs, meets criteria for the generally less expensive disposal method,
namely land application and surface disposal.
In addition, the potential fate and toxicity of pollutants of concern associated with IWC
wastewater are evaluated based on known characteristics of each chemical. Recent literature and
studies are also reviewed, and State environmental agencies are contacted for evidence of
documented environmental impacts on aquatic life, human health, POTW operations, and on the
quality of receiving water.
These analyses are performed for discharges of the 11 commercial industrial waste
combustors (8 direct dischargers and 3 indirect dischargers) identified as within the scope of this
regulation. This report provides the results of these analyses, organized by the type of discharge
(direct and indirect).
Comparison of Tnsfream Concentrations with Ambient Water Quality Criteria
at POTWs
The water quality modeling results for 8 direct IWC facilities discharging 17 pollutants
(metals) to 8 receiving streams indicate that at current discharge levels, instream concentrations
of 3 pollutants are projected to exceed acute aquatic life priteria or toxic effect levels in 1 of the
8 receiving streams (12 percent). Instream concentrations of 8 pollutants are projected to exceed
chrnnic aquatic life criteria or toxic effect levels in 50 percent (4 of the total 8) of the receiving
streams. The proposed BAT regulatory option will reduce acute aquatic lifp excursions from
3 pollutants to 2 pollutants. The regulatory option will also reduce the chronic aquatic life
excursions from 8 pollutants to 7 pollutants in the 4 receiving streams. Additionally, at current
discharge levels, instream concentrations of 2 pollutants (using a target risk of 10"6 (1E-6) for
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carcinogens) are projected to exceed human health criteria or toxic effect levels (developed for
consumption of water and organisms) in 50 percent (4 of the total 8) receiving streams. The
instream concentration of 1 pollutant (using a target risk of 10"6 (1E-6) for carcinogens) is
projected to exceed the human health criteria or toxic effect levels (developed for organisms
consumption only) in 25 percent (2 of the total 8) receiving streams. The proposed HAT
regulatory option will eliminate human health criteria or toxic effect level (developed for
consumption of water and organisms) excursions by 1 pollutant, but 4 receiving streams are still
impacted. Human health criteria or toxic effect level (developed for organisms consumption
only) excursions are eliminated in 1 of the 2 impacted receiving streams at the proposed HAT
regulatory option. Under the proposed BAT regulatory option, pollutant loadings are reduced
29 percent.
Modeling results for 3 indirect IWC facilities that discharge 17 pollutants (metals) to 3
POTWs located on 3 receiving streams indicate that at current discharge levels no instream
pollutant concentrations are expected to exceed acute aquatic life criteria or toxic effect levels.
The instream concentration of 1 pollutant is projected to exceed chronic aquatic life criteria or
toxic effect levels in 33 percent (1 of the total 3) receiving streams. The proposed
regulatory option will eliminate this chronic aquatic life excursion. Additionally, at current
discharge levels, the instream concentration of 1 pollutant is projected to exceed both human
health criteria or toxic effect levels (developed for consumption of water and organisms) and
human health criteria or toxic effect levels (developed for organisms consumption only) in 1
receiving stream. Projected excursions are eliminated by the proposed pretreatment regulatory
option. Pollutant loadings are reduced 97 percent.
In addition, POTW inhibition problems and sludge contamination problems are projected
only at current discharge levels. Inhibition problems are projected to occur at 33 percent (1 of
the 3) of the POTWs from the discharge of 1 pollutant. The proposed pretreatment regulatory
option eliminates any inhibition problem. Sludge contamination is projected to occur at 67 percent
vui
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(2 of the 3) of the POTWs due to the discharge of 3 pollutants. The proposed pretreatment
regulatory option will also eliminate sludge contamination problems.
Human Health Risks and Benefits
The excess annual cancer cases at current discharge levels and, therefore, at proposed
BAI and proposed prefreatment discharge levels are projected to be far less than 0.5 for all
populations evaluated from the ingestion of contaminated fish and drinking water for both direct
and indirect IWC wastewater discharges. A monetary value of this benefit to society is, therefore,
not projected. Systemic toxicant effects are projected from fish consumption for both direct and
indirect discharges. For direct discharges, systemic effects are projected to result from the
discharge of 3 pollutants to 3 receiving streams at current discharge levels. An estimated
population of 705 subsistence anglers and their families are projected to be affected. At the
proposed BAT regulatory option, systemic toxicity is limited to 1 pollutant in 1 receiving stream
with 373 subsistence anglers and their families remaining exposed; a 47 percent reduction. For
indirect discharges, systemic toxicant effects are projected at current discharge levels due to the
discharge of 2 pollutants to 1 receiving stream. An estimated population of 249 subsistence
anglers and their families are projected to be affected. No systemic toxicant effects are projected
at proposed pretreafment discharge levels. Monetary values for the reduction of systemic toxic
effects cannot currently be estimated.
Ecological Benefits
Potential ecological benefits of the proposed regulation, based on improvements in
recreational fishing habitats, are projected for only indirect IWC wastewater discharges, because
the proposed regulation is not projected to completely eliminate instream concentrations in excess
of aquatic life and human health ambient water quality criteria (AWQC) in any stream receiving
wastewater discharge from direct discharge IWC facilities. For indirect discharges, concentrations
in excess of AWQC are projected to be eliminated at 1 receiving stream as a result of the
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proposed prefrpatmpnf regulatory option. The monetary value of improved recreational fishing
opportunity is estimated by first calculating the baseline value of the receiving stream using a
value per person day of recreational fishing, and the number of person-days fished on the
receiving stream. The value of improving water quality in this fishery, based on the increase in
value to anglers of achieving contaminant-free fishing, is then calculated. The resulting estimate
of the increase in value of recreational fishing to anglers on the improved receiving stream is
$78,600 to $281 ,000 (1992 dollars).
The estimated benefit of improved recreational fishery opportunities is only a limited
measure of the value to society of the improvements in aquatic habitats expected to result from
the proposed regulation. Additional benefits, which could not be quantified in this assessment,
include increased assimilation capacity of the receiving stream, protection of terrestrial wildlife
and birds that consume aquatic organisms, maintenance of an aesthetically pleasing environment,
and improvements to other recreational activities such as swimming, water skiing, boating, and
wildlife observation. Such activities contribute to the support of local and State economies.
Ecnnnmir Prnrfnptivity
Potential economic productivity benefits, based on reduced sewage sludge contamination
and sewage sludge disposal costs, are projected at 1 POTW that will meet land application
pollutant concentration limits as a result of the proposed regulation. Savings in disposal cost are
estimated at $7,400 (1992 dollars). In addition, 2 POTWs (1 additional) are expected to accrue
a modest benefit through reduced record-keeping requirements and exemption from certain sewage
sludge management practices. A monetary value for these modest benefits cannot currently be
estimated.
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Pollutant Fate and TnviHty
EPA identified 21 pollutants of concern (10 priority pollutants, 4 conventional/classical
pollutant parameters, and 7 nonconventional pollutants) in wastestreams from IWC facilities.
Seventeen (17) of these pollutants (all metals) are evaluated to assess their potential fate and
toxicity based on known characteristics of each chemical.
Most of the 17 pollutants have at least one known toxic effect. Based on available
physical-chemical properties and aquatic life and human health toxicity data for these pollutants,
10 exhibit moderate to high toxicity to aquatic life; 3 are classified as known or probable human
carcinogens; 13 are human systemic toxicants; 13 have drinking water values; and 10 are
designated by EPA as priority pollutants. In terms of projected partitioning, 4 have a moderate
to high potential to bioaccumulate in aquatic biota, potentially accumulating in the food chain and
causing increased risk to higher trophic level organisms and to exposed human populations via
consumption offish and shellfish. All of the modeled pollutants are metals, which in general are
not applicable to evaluation based on volatility and adsorption to solids. It is assumed that all of
the metals have a high potential to sorb to solids.
The impacts of the 4 conventional/classical pollutants are not evaluated when modeling the
effect of the proposed regulation oh receiving stream water quality and POTW operations or when
evaluating the potential fate and toxicity of discharged pollutants. These pollutants are total
suspended solids (TSS), chemical oxygen demand (COD), total dissolved solids (TDS), and total
organic carbon (TOG). The discharge of these pollutants can have adverse effects on human
health and the environment. For example, habitat degradation can result from increased
suspended particulate matter that reduces light penetration, and thus primary productivity, or from
accumulation of sludge particles that alter benthic spawning grounds and feeding habitats. High
COD levels can deplete oxygen concentrations, which can result in mortality or other adverse
effects on fish. High TOC levels may interfere with water quality by causing taste and odor
problems and mortality in fish.
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Documented Tfovirnnmenta] Impacts
This assessment also summarizes documented environmental impacts on aquatic life,
human health, POTW operations, and receiving stream water quality. The summaries are based
on a review of published literature abstracts, State 304(1) Short Lists, State Fishing Advisories,
and contact with State environmental agencies. Two (2) direct discharging IWC facilities and 2
POTWs receiving the discharge from 2 IWC facilities are identified by States as being point
sources causing water quality problems and are included on their 304(1) Short List. State contacts
indicate that of the two direct facilities, one is no longer in operation and the other is currently
in compliance with its permit limits and is no longer a source of impairment. Both of the POTWs
listed are also currently in compliance for the listed pollutants. In addition, two IWC facilities
are located on waterbodies with State-issued fish consumption advisories. However, the advisories
are based on dioxins, which are not proposed for regulation for the IWC industry.
Xll
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1. INTRODUCTION
The purpose of this report is to present an assessment of the water quality benefits of
controlling the discharge of wastewater from commercial industrial waste combustors (IWCs) to
surface waters and publicly-owned treatment works (POTWs). Potential aquatic life and human
health impacts of direct discharges on receiving stream water quality and of indirect discharges
on POTWs and their receiving streams are projected at current, proposed BAT (Best Available
Technology), and proposed PSES (Pretreatment Standards for Existing Sources) levels by
quantifying pollutant releases and by using stream modeling techniques. The potential benefits
to human health are evaluated by: (1) comparing estimated instream concentrations to health-based
water quality toxic effect levels or U.S. Environmental Protection Agency (EPA) published water
quality criteria; and (2) estimating the potential reduction of carcinogenic risk and noncarcinogenic
hazard (systemic) from consuming contaminated fish or drinking water. Reduction in
carcinogenic risks is monetized, if applicable, using estimated willingness-to-pay values for
avoiding premature mortality. Potential ecological benefits are projected by estimating
improvements in recreational fishing habitats and, in turn, by projecting, if applicable, a monetary
value for enhanced recreational fishing opportunities. Economic productivity benefits are
estimated based on reduced POTW sewage sludge contamination (thereby increasing the number
of allowable sludge uses or disposal options). In addition, the potential fate and toxicity of
pollutants of concern associated with IWC wastewater are evaluated based on known
characteristics of each chemical. Recent literature and studies are also reviewed for evidence of
documented environmental impacts (e.g., case studies) on aquatic life, human health, and POTW
operations and for impacts on the quality of receiving water.
While this report does not evaluate impacts associated with reduced releases of one
conventional pollutant (total suspended solids [TSS]) and three classical pollutant parameters
(chemical oxygen demand [COD], total dissolved solids [TDS], and total organic carbon [TOC]),
the discharge of these pollutants can have adverse effects on human health and the environment.
For example, habitat degradation can result from increased suspended particulate matter that
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reduces light penetration and primary productivity, or from accumulation of sludge particles that
alter benthic spawning grounds and feeding habitats. High COD levels can deplete oxygen levels,
which can result in mortality or other adverse effects in fish. High TOC levels may interfere with
water quality by causing taste and odor problems and mortality in fish.
Hie following sections of this report describe: (1) the methodology used in the evaluation
of projected water quality impacts and projected impacts on POTW operations for direct and
indirect discharging facilities (including potential human health risks and benefits, ecological
benefits, and economic productivity benefits) in the evaluation of the potential fate and toxicity
of pollutants of concern, and in the evaluation of documented environmental impacts; (2) data
sources used to evaluate water quality impacts such as plant-specific data, information used to
evaluate POTW operations, water quality criteria, and information used to evaluate human health
risks and benefits, ecological benefits, economic productivity benefits, pollutant fate and toxicity,
and documented environmental impacts; (3) a summary of the results of this analysis; and (4) a
complete list of references cited in this report. The various appendices presented in Volume n
provide additional detail on the specific information addressed in the main report. These
appendices are available in the administrative record.
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2. METHODOLOGY
2.1 Projected Wafpr Quality Imparts
The water quality impacts and associated risks/benefits of IWC discharges at various
treatment levels are evaluated by: (1) comparing projected instream concentrations with ambient
water quality criteria,1 (2) estimating the human health risks and benefits associated with the
consumption of fish and drinking water from waterbodies impacted by the IWC industry, (3)
estimating the ecological benefits associated with improved recreational fishing habitats on
impacted waterbodies, and (4) estimating the economic productivity benefits based on reduced
sewage sludge contamination at POTWs receiving the wastewater of IWC facilities. The
methodologies used in this evaluation are described in detail below.
2.1.1 Comparison of Instream Concentrations with Ambient Water Quality Criteria
Current and proposed pollutant releases are quantified and compared, and potential aquatic
life and human health impacts resulting from current and proposed pollutant releases are evaluated
using stream modeling techniques. Projected instream concentrations for each pollutant are
compared to EPA water quality criteria or, for pollutants for which no water quality criteria have
been developed, to toxic effect levels (i.e., lowest reported or estimated toxic concentration).
Inhibition of POTW operation and sludge contamination are also evaluated. The following three
sections (Le., Section 2.1.1.1 through Section 2.1.1.3) describe the methodology and assumptions
used for evaluating the impact of direct and indirect discharging facilities.
In performing this analysis, EPA used guidance documents published by EPA that recommend numeric human health
and aquatic life water quality criteria for numerous pollutants. States often consult these guidance documents when
adopting water quality criteria as part of their water-quality standards. However, because those State-adopted criteria
may vary, EPA used the nationwide criteria guidance as the most representative values.
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2.1.1.1 Direct Discharging Facilities
Using a stream dilution model that does not account for fate processes other than complete
immediate mixing, projected instream concentrations are calculated at current and proposed BAT
treatment levels for stream segments with direct discharging facilities. For stream segments with
multiple IWC facilities, pollutant loadings are summed, if applicable, before concentrations are
calculated. The dilution model used for estimating instream concentrations is as follows.
LIOD
FF + SF
x CF
(Eq. 1)
where:
Q,
L
OD
FF
SF
CF
instream pollutant concentration (micrograms per liter
facility pollutant loading (pounds/year jibs/year])
facility operation (days/year)
facility flow (million gallons/day [gal/day])
receiving stream flow (million gal/day)
conversion factors for units
The facility-specific data (i.e., pollutant loading, operating days, facility flow, and stream
flow) used in Eq. 1 are derived from various sources as described in Section 3.1.1 of this report.
One of three receiving stream flow conditions (1Q10 low flow, 7Q10 low flow, and harmonic
mean flow) is used for the two treatment levels; use depends on the type of criterion or toxic
effect level intended for comparison. The 1Q10 and 7Q10 flows are the lowest 1-day and the
lowest consecutive 7-day average flow during any 10-year period, respectively, and are used to
estimate potential acute and chronic aquatic life impacts, respectively, as recommended in the
Technical Support Document for Water Quality-based Toxics Control (U.S. EPA, 1991a). The
harmonic mean flow is defined as the inverse mean of reciprocal daily arithmetic mean flow
values and is used to estimate potential human health impacts. EPA recommends the long-term
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harmonic mean flow as the design flow for assessing potential human health impacts, because it
provides a more conservative estimate than the arithmetic mean flow. 7Q10 flows are not
appropriate for assessing potential human health impacts, because they have no consistent
relationship with the long-term mean dilution.
For assessing impacts on aquatic life, the facility operating days are used to represent the
exposure duration; the calculated instream concentration is thus the average concentration on days
the facility is discharging wastewater. For assuming long-term human health impacts, the
operating days (exposure duration) are set at 365 days; the calculated instream concentration is
thus the average concentration on all days of the year. Although this calculation for human health
impacts leads to a lower calculated concentration because of the additional dilution from days
when the facility is not in operation, it is consistent with the conservative assumption that the
target population is present to consume drinking water and contaminated fish every day for an
entire lifetime.
Because stream flows are not available for hydrologically complex waters such as bays,
estuaries, and oceans, site-specific critical dilution factors (CDFs) or estuarine dissolved
concentration potentials (DCPs) are used to predict pollutant concentrations for facilities
discharging to estuaries and bays, if applicable, as follows:
(Eq.2)
where:
L
OD
FF
estuary pollutant concentration C"g/L)
facility pollutant loading (Ibs/year)
facility operation (days/year)
facility flow (million gal/day)
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CDF = critical dilution factor
CF = conversion factors for units
C = L x DCP x CF
(Eq.3)
where:
L
DCP
CF
estuary pollutant concentration (^g/L)
facility pollutant loading (Ibs/year)
dissolved concentration potential (milligrams per liter [mg/L])
conversion factor for units
Site-specific critical dilution factors are obtained from a survey of States and Regions conducted
by EPA's Office of Pollution Prevention and Toxics (OPPT) Mixing Zone Dilution Factors for
New Chemical Exposure Assessments, Draft Report, (U.S. EPA, 1992a). Acute CDFs are used
to evaluate acute aquatic Ufe effects; whereas, chronic CDFs are used to evaluate chronic aquatic
life or adverse human health effects. It is assumed that the drinking water intake and fishing
location are at the edge of the chronic mixing zone.
The Strategic Assessment Branch of the National Oceanic and Atmospheric
Administration's (NOAA) Ocean Assessments Division has developed DCPs based on freshwater
inflow and salinity gradients to predict pollutant concentrations in each estuary in the National
Estuarine Inventory (NET) Data Atlas. These DCPs are applied to predict concentrations. They
also do not consider pollutant fate and are designed strictly to simulate concentrations of
nonreactive dissolved substances. In addition, the DCPs reflect the predicted estuary-wide
response and may not be indicative of site-specific locations.
Water quality excursions are determined by dividing the projected instream (Eq. 1) or
estuary (Eq. 2 and Eq. 3) pollutant concentrations by EPA ambient water quality criteria or toxic
effect levels. A value greater than 1.0 indicates an excursion.
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2.1.1.2 Indirect Discharging Facilities
Assessing the impacts of indirect discharging facilities is a two-stage process. First, water
quality impacts are evaluated as described in Section (a) below. Next, impacts on POTWs are
considered as described in Section (b) that follows.
(a) Water Quality Impacts
A stream dilution model is used to project receiving stream impacts resulting from releases
by indirect discharging facilities as shown in Eq. 4. For stream segments with multiple IWC
facilities, pollutant loadings are summed, if applicable, before concentrations are calculated. The
finality-specific data used in Eq. 4 are derived from various sources as described in Section 3.1.1
of this report. Three receiving stream flow conditions (1Q10 low flow, 7Q10 low flow, and
harmonic mean flow) are used for the current and proposed pretreatment options. Pollutant
concentrations are predicted for POTWs located on bays and estuaries using site-specific CDFs
or NOAA's DCP calculations (Eq. 5 and Eq. 6).
(L/OD) x (l~TMT) X CF
PF + SF
(Eq.4)
where:
L
OD
TMT
PF
SF
CF
instream pollutant concentration
facility pollutant loading (Ibs/year)
facility operation (days/year)
POTW treatment removal efficiency
POTW flow (million gal/day)
receiving stream flow (million gal/day)
conversion factors for units
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L/OD x (l-TMT)}
PF
x CF / CDF
(Eq.5)
where:
L
OD
TMT
PF
CDF
CF
estuary pollutant concentration
facility pollutant loading (Ibs/year)
facility operation (days/year)
POTW treatment removal efficiency
POTW flow (million gal/day)
critical dilution factor
conversion factors for units
Ce=Lx (l-TMT) x DCPx CF
(Eq. 6)
where:
L
TMT
DCP
CF
estuary pollutant concentration
facility pollutant loading (Ibs/year)
POTW treatment removal efficiency
dissolved concentration potential (mg/L)
conversion factors for units
Potential impacts on freshwater quality are determined by comparing projected instream
pollutant concentrations (Eq. 4) at reported POTW flows and at 1Q10 low, 7Q10 low, and
harmonic mean receiving stream flows with EPA water quality criteria or toxic effect levels for
the protection of aquatic life and human health; projected estuary pollutant concentrations (Eq.
5 and Eq. 6), based on CDFs or DCPs, are compared to EPA water quality criteria or toxic effect
levels to determine impacts. Water quality criteria excursions are determined by dividing the
projected instream or estuary pollutant concentration by the EPA water quality criteria or toxic
effect levels. (See Section 2.1.1.1 for discussion of streamflow conditions, application of CDFs
8
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or DCPs, assignment of exposure duration, and comparison with, criteria or toxic effect levels.)
A value greater than 1.0 indicates an excursion.
(b) Impacts on POTWs
Impacts on POTW operations are calculated in terms of inhibition of POTW processes
(i.e., inhibition of microbial degradation) and contamination of POTW sludges, defined as a
sewage sludge concentration that exceeds the levels at which sewage sludge may be land applied
or surface disposed under 40 CFR Part 503. Inhibition of POTW operations is determined by
dividing calculated POTW influent levels (Eq. 7) with chemical-specific inhibition threshold
levels. Excursions are indicated by a value greater than 1.0.
PF
(Eq. 7)
where:
L
OD
PF
CF
POTW influent concentration
facility pollutant loading (Ibs/year)
facility operation (days)
POTW flow (million gal/day)
conversion factors for units
Contamination of sludge (thereby limiting its use for land application, etc.) is evaluated by
dividing projected pollutant concentrations in sludge (Eq. 8) by available EPA-developed criteria
values for sludge. A value greater than 1.0 indicates an excursion.
Csp = Cpi x TMT x PART x SGF
(Eq. 8)
where:
-------
C,p = sludge pollutant concentration (milligrams per kilogram [mg/kg])
Cp; «= POTW influent concentration (>g/L)
TMT = POTW treatment removal efficiency
PART = chemical-specific sludge partition factor
SGF = sludge generation factor (5.96 parts per million Ippm])
Facility-specific data and information used to evaluate POTWs are derived from the
sources described in Sections 3.1.1 and 3.1.2. For facilities that discharge to the same POTW,
their individual loadings are summed, if applicable, before the POTW influent and sludge
concentrations are calculated.
The partition factor is a measure of the tendency for the pollutant to partition in sludge
when it is removed from wastewater. For predicting sludge generation, the model assumes that
1,400 pounds of sludge are generated for each million gallons of wastewater processed (Metcalf
& Eddy, 1972). This results in a sludge generation factor of 5.96 mg/kg per /zg/L (that is, for
every 1 ^g/L of pollutant removed from wastewater and partitioned to sludge, the concentration
in sludge is 5.96 mg/kg dry weight).
2.1.1.3 Assumptions and Caveats
The following major assumptions are used in this analysis:
Background concentrations of each pollutant, both in the receiving stream
and in the POTW influent, are equal to zero; therefore, only the impacts
of discharging facilities are evaluated.
Facilities are assumed to operate 365 days per year.
An exposure duration of 365 days is used to determine the likelihood of
actual excursions of human health criteria or toxic effect levels.
Complete mixing of discharge flow and stream flow occurs across the
stream at the discharge point. This mixing results in the calculation of an
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"average stream" concentration, even though the actual concentration may
vary across the width and depth of the stream.
The process water at each iacility and the water discharged to a POTW are
obtained from a source other than the receiving stream.
The pollutant load to the receiving stream is assumed to be continuous and
is assumed to be representative of long-term facility operations. These
assumptions may overestimate risks to human health and aquatic life, but
may underestimate potential short-term effects.
1Q10 and 7Q10 receiving stream flow rates are used to estimate aquatic life
impacts, and harmonic mean flow rates are used to estimate human health
impacts. 1Q10 low flows are estimated using the results of a regression
analysis conducted by Versar, Inc. for EPA's Office of Pollution
Prevention and Toxics (OPPT) of 1Q10 and 7Q10 flows from
representative U.S. rivers and streams taken from Upgrade of Flow
Statistics Used to Estimate Surface Water Chemical Concentrations for
Aquatic and Human Exposure Assessment (Versar, 1992). Harmonic mean
flows are estimated from the mean and 7Q10 flows as recommended in the
Technical Support Document for Water-QuaUty-based Toxics Control (U.S.
EPA, 1991a). These flows may not be the same as those used by specific
States to assess impacts.
Pollutant fate processes, such as sediment adsorption, volatilization, and
hydrolysis, are not considered. This may result in estimated instream
concentrations that are environmentally conservative (higher).
Pollutants without a specific POTW treatment removal efficiency provided
by EPA or found in the literature are assigned a removal efficiency of zero;
pollutants without a specific partition factor are assigned a value of zero.
Sludge criteria levels are only available for seven pollutants—arsenic,
cadmium, copper, lead, mercury, selenium, and zinc.
Water quality criteria or toxic effect levels developed for freshwater
organisms are used in the analysis of facilities discharging to estuaries or
bays.
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2.1.2 Estimation of Human Health Risks and Benefits
The potential benefits to human health are evaluated by estimating the risks (carcinogenic
and noncarcinogenic hazard [systemic]) associated with reducing pollutant levels in fish tissue and
drinking water from current to proposed treatment levels. Reduction in carcinogenic risks is
monetized, if applicable, using estimated willingness-to-pay values for avoiding premature
mortality. The following three sections (i.e., Section 2.1.2.1 through Section 2.1.2.3) describe
the methodology and assumptions used to evaluate the human health risks and benefits from the
consumption of fish tissue and drinking water derived from waterbodies impacted by direct and
indirect discharging facilities.
2.1.2.1 Fish Tissue
To determine the potential benefits, in terms of reduced cancer cases, associated with
reducing pollutant levels in fish tissue, lifetime average daily doses (LADDs) and individual risk
levels are estimated for each pollutant discharged from a facility based on the instream pollutant
concentrations calculated at current and proposed treatment levels in the site-specific stream
dilution analysis. (See Section 2.1.1.) Estimates are presented for sport anglers, subsistence
anglers, and the general population. LADDs are calculated as follows:
LADD = (CxIRx BCF xFxD)/(BWxLT)
(Eq.9)
where:
LADD = potential lifetime average daily dose (milligrams per kilogram per day
[mg/kg/day])
C = exposure concentration (mg/L)
IR = ingestion rate (See Section 2.1.2.3 - Assumptions)
BCF = bioconcentration factor, (liters per kilogram [L/kg] (whole body x 0.5)
F = frequency duration (365 days/year)
12
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D = exposure duration (70 years)
BW = body weight (70 kg)
LT = lifetime (70 years x 365 days/year)
Individual risks are calculated as follows:
R = LADD x SF
(Eq. 10)
where:
R = individual risk level
LADD = potential lifetime average daily dose (mg/kg/day)
SF = potency slope factor (mg/kg-day)"1
The estimated individual pollutant risk levels are then applied to the potentially exposed
populations of sport anglers, subsistence anglers, and the general population to estimate the
potential number of excess annual cancer cases occurring over the life of the population. The
number of excess cancer cases is then summed on a pollutant, facility, and overall industry basis.
The number of reduced cancer cases are assumed to be the difference between the estimated risks
at current and proposed treatment levels.
A monetary value of benefits to society from avoided cancer cases is estimated if current
wastewater discharges result in excess annual cancer cases greater than 0.5. The valuation of
benefits is based on estimates of society's willingness-to-pay to avoid the risk of cancer-related
premature mortality. Although it is not certain that all cancer cases will result in death, to develop
a worst case estimate for this analysis, avoided cancer cases are valued on the basis of avoided
mortality. To value mortality, a range of values recommended by an EPA, Office of Policy
Analysis (OPA) review of studies quantifying individuals' willingness-to-pay to avoid risks to life
is used (Fisher, Chestnut, and Violette, 1989; and Violette and Chestnut, 1986). The reviewed
studies used hedonic wage and contingent valuation analyses in labor markets to estimate the
13
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amounts that individuals are willing to pay to avoid slight increases in risk of mortality or will
need to be compensated to accept a slight increase in risk of mortality. The willingness-to-pay
values estimated in these studies are associated with small changes in the probability of mortality.
To estimate a willingness-to-pay for avoiding certain or high probability mortality events, they
are extrapolated to the value for a 100 percent probability event.2 The resulting estimates of the
value of a "statistical life saved" are used to value regulatory effects that are expected to reduce
the incidence of mortality.
From this review of willingness-to-pay studies, OPA recommends a range of $1.6 to $8.5
million (1986 dollars) for valuing an avoided event of premature mortality or a statistical life
saved. A more recent survey of value of life studies by Viscusi (1992) also supports this range
with the finding that value of life estimates are clustered in the range of $3 to $7 million (1990
dollars). For this analysis, the figures recommended in the OPA study are adjusted to 1992 using
the relative change in the Employment Cost Index of Total Compensation for All Civilian Workers
from 1986 to 1992 (29 percent). Basing the adjustment in the willingness-to-pay values on change
in nominal Gross Domestic Product (GDP) instead of change in inflation, accounts for the
expectation that willingness-to-pay to avoid risk is a normal economic good, and, accordingly,
society's willingness-to-pay to avoid risk will increase as national income increases. Updating to
1992 yields a range of $2.1 to $11.0 million.
Potential reductions in risks due to reproductive, developmental, or other chronic and
subchronic toxic effects are estimated by comparing the estimated lifetime average daily dose and
the oral reference dose (RfD) for a given chemical pollutant as follows:
HQ =
(Bq.ll)
obese estimates, however, do not represent the willingness-to-pay to avoid the certainty of death.
14
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where:
HQ
OKI
RfD
hazard quotient
oral intake (LADD x BW, mg/day)
reference dose (mg/day assuming a body weight of 70 kg)
A hazard index (i.e., sum of individual pollutant hazard quotients) is then calculated for
each facility or receiving stream. A hazard index greater than 1.0 indicates that toxic effects may
occur in exposed populations. The size of the subpopulations affected are summed and compared
at the various treatment levels to assess benefits in terms of reduced systemic toxicity. While a
monetary value of benefits to society associated with a reduction in the number of individuals
exposed to pollutant levels likely to result in systemic health effects could not be estimated, any
reduction in risk is expected to yield human health related benefits.
2.1.2.2 Drinking Water
Potential benefits associated with reducing pollutant levels in drinking water are determined
in a similar manner. LADDs for drinking water consumption are calculated as follows:
LADD = (CxIRxFxD) / (BWxLT)
(Eq. 12)
where:
LADD
C
IR
F
D
BW
LT
potential lifetime average daily dose (mg/kg/day)
exposure concentration (mg/L)
ingestion rate (2L/day)
frequency duration (365 days/year)
exposure duration (70 years)
body weight (70 kg)
lifetime (70 years x 365 days/year)
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Estimated individual pollutant risk levels greater than 10"6 (1E-6) are applied to the population
served downstream by any drinking water utilities within 50 miles from each discharge site to
determine the number of excess annual cancer cases that may occur during the life of the
population. Systemic toxicant effects are evaluated by estimating the sizes of populations exposed
to pollutants from a given facility, the sum of whose individual hazard quotients yields a hazard
index (HI) greater than 1.0. A monetary value of benefits to society from avoided cancer cases
is estimated, if applicable, as described in Section 2.1.2.1.
2.1.2.3 Assumptions and Caveats
The following assumptions are used in the human health risks and benefits analyses:
A linear relationship is assumed between pollutant loading reductions and
benefits attributed to the cleanup of surface waters.
Synergistic effects of multiple chemicals on aquatic ecosystems are not
assessed; therefore, the total benefit of reducing toxics may be
underestimated.
The total number of persons who might consume recreationally caught fish
and the number who rely upon fish on a subsistence basis in each State is
estimated, in part, by assuming that these anglers regularly share their catch
with family members. Therefore, the number of anglers in each State is
multiplied by the average household size in each State. The remainder of
the population of these States is assumed to be the "general population"
consuming commercially caught fish.
Five percent of the resident anglers in a given State are assumed to be
subsistence anglers; the other 95 percent are assumed to be sport anglers.
Commercially or recreationally valuable species are assumed to occur or to
be taken in the vicinity of the discharges included in the evaluation.
Ihgestion rates of 6.5 grams per day for the general population, 30 grams
per day (30 years) + 6.5 grams per day (40 years) for sport anglers, and
140 grams per day for subsistence anglers are used in the analysis of fish
tissue (Exposure Factors Handbook, U.S. EPA, 1989a)
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All rivers or estuaries within a State are equally fished by any of that
State's resident anglers, and the fish are consumed only by the population
within that State.
Populations potentially exposed to discharges to rivers or estuaries that
border more than one State are estimated based only on populations within
the State in which the facility is located.
The size of the population potentially exposed to fish caught in an impacted
water body in a given State is estimated based on the ratio of impacted river
miles to total river miles in that State or impacted estuary square miles to
total estuary square miles in that State. The number of miles potentially
impacted by a facility's discharge is assumed to be 50 miles for rivers and
the total surface area of the various estuarine zones for estuaries.
%
Pollutant fate processes (e.g., sediment adsorption, volatilization,
hydrolysis) are not considered in estimating the concentration in drinking
water or fish; consequently, estimated concentrations are environmentally
conservative (higher).
2.1.3 Estimation of Ecological Benefits
The potential ecological benefits of the proposed regulation are evaluated by estimating
improvements in the recreational fishing habitats that are impacted by IWC wastewater discharges.
Stream segments are first identified for which the proposed regulation is expected to eliminate all
occurrences of pollutant concentrations in excess of both aquatic life and human health ambient
water quality criteria (AWQC) or toxic effect levels. (See Section 2.1.1.) The elimination of
pollutant concentrations in excess of AWQC is expected to result in significant improvements in
aquatic habitats. These improvements in aquatic habitats are then expected to improve the quality
and value of recreational fishing opportunities. The estimation of the monetary value to society
of improved recreational fishing opportunities is based on the concept of a "contaminant-free
fishery" as presented by Lyke (1993).
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Research by Lyfce (1993) shows that anglers may place a significantly higher value on a
contaminant-free fishery than a fishery with some level of contamination. Specifically, Lyke
estimates the consumer surplus3 associated with Wisconsin's recreational Lake Michigan trout and
salmon fishery, and the additional value of the fishery if it was completely free of contaminants
affecting aquatic life and human health. Lyke's results are based on two analyses:
A multiple site, trip generation, travel cost model was used to estimate net benefits
associated with the fishery under baseline (i.e., contaminated) conditions.
A contingent valuation model was used to estimate willingness-to-pay values for
the fishery if it was free of contaminants.
Both analyses used data collected from licensed anglers before the 1990 season. The estimated
incremental benefit values associated with freeing the fishery of contaminants range from 11.1
percent to 31.3 percent of the value of the fishery under current conditions.
To estimate the gain in value of stream segments identified as showing improvements in
aquatic habitats as a result of the proposed regulation, the baseline recreational fishery value of
the stream segments are estimated on the basis of estimated annual person-days of fishing per
segment and estimated values per person-day of fishing. Annual person-days of fishing per
segment are calculated using estimates of the affected (exposed) recreational fishing populations.
(See Section 2.1.2.) The number of anglers are multiplied by estimates of the average number
of fishing days per angler in each State to estimate the total number of fishing days for each
segment. The baseline value for each fishery is then calculated by multiplying the estimated total
number of fishing days by an estimate of the net benefit that anglers receive from a day of fishing
where net benefit represents the total value of the fishing day exclusive of any fishing-related costs
(license fee, travel costs, bait, etc.) incurred by the angler. In this analysis, a range of median
Consumer surplus is generally recognized as the best measure from a theoretical basis for valuing die net economic
welfare or benefit to consumers from consuming a particular good or service. An increase or decrease in consumer
surplus for particular goods or services as the result of regulation is a primary measure of the gain or loss in consumer
welfare resulting from the regulation.
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net benefit values for warm water and cold water fishing days, $27.75 and $35.14, respectively,
in 1992 dollars is used. Summing over all benefiting stream segments provides a total baseline
recreational fishing value of incinerator stream segments that are expected to benefit by
elimination of pollutant concentrations in excess of AWQC.
To estimate the increase in value resulting from elimination of pollutant concentrations in
excess of AWQC, the baseline value for benefiting stream segments are multiplied by the
incremental gain in value associated with achievement of the "contaminant-free" condition. As
noted above, Lyke's estimate of the increase in value ranged from 11.1 percent to 31.3 percent.
Multiplying by these values yields a range of expected increase in value for the IWC stream
segments expected to benefit by elimination of pollutant concentrations in excess of AWQC.
2.1.3.1
Assumptions and Caveats
The following major assumptions are used in the ecological benefits analysis:
Background concentrations of the IWC pollutants of concern in the
receiving stream are not considered.
The estimated benefit of improved recreational fishing opportunities is only
a limited measure of the value to society of the improvements in aquatic
habitats expected to result from the proposed regulation; increased
assimilation capacity of the receiving stream, improvements in taste and
odor, or improvements to other recreational activities, such as swimming
and wildlife observation, are not addressed.
Significant simplifications and uncertainties are included in the assessment.
This may overestimate or underestimate the monetary value to society of
improved recreational fishing opportunities. (See Sections 2.1.1.3 and
2.1.2.3.)
Potential overlap in valuation of improved recreational fishing opportunities
and avoided cancer cases from fish consumption may exist. This potential
is considered to be minor in terms of numerical significance.
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2.1.4 Estimation of Economic Productivity Benefits
Potential economic productivity benefits are estimated based on reduced sewage sludge
contamination due to the proposed regulation. The treatment of wastewaters generated by IWC
facilities produces a sludge that contains pollutants removed from the wastewaters. As required
by law, POTWs must use environmentally sound practices in managing and disposing of this
sludge. The proposed pretreatment levels are expected to generate sewage sludges with reduced
pollutant concentrations. As a result, the POTWs may be able to use or dispose of the sewage
sludges with reduced pollutant concentrations at lower costs.
To determine the potential benefits, in terms of reduced sewage sludge disposal costs,
sewage sludge pollutant concentrations are calculated at current and proposed pretreatment levels.
(See Section 2.1.1.2.) Pollutant concentrations are then compared to sewage sludge pollutant
limits for surface disposal and land application (minimum ceiling limits and pollutant
concentration limits). If, as a result of the proposed pretreatment, a POTW meets all pollutant
limits for a sewage sludge use or disposal practice, that POTW is assumed to benefit from the
increase in sewage sludge use or disposal options. The amount of the benefit deriving from
changes in sewage sludge use or disposal practices depends on the sewage sludge use or disposal
practices employed under current levels. This analysis assumes that POTWs choose the least
expensive sewage sludge use or disposal practice for which their sewage sludge meets pollutant
limits. POTWs with sewage sludge that qualifies for land application in the baseline are assumed
to dispose of their sewage sludge by land application; likewise, POTWs with sewage sludge that
meets surface disposal limits (but not land application ceiling or pollutant limits) are assumed to
dispose of their sewage sludge at surface disposal sites.
The economic benefit for POTWs receiving wastewater from an incinerator facility is
calculated by multiplying the cost differential between baseline and post-compliance sludge use
or disposal practices by the quantity of sewage sludge that shifts into meeting land application
20
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(minimum ceiling limits and pollutant concentration limits) or surface disposal limits. Using these
cost differentials, reductions in sewage sludge use or disposal costs are calculated for each POTW
(Eq. 13):
SCR = PF x S x CD x PD x CF
(Eq. 13)
where:
SCR = estimated POTW sewage sludge use or disposal cost reductions resulting
from the proposed regulation (1992 dollars)
PF = POTW flow (million gal/year)
S = sewage sludge to wastewater ratio (1,400 Ibs (dry weight) per million
gallons of water)
CD = estimated cost differential between least costly composite baseline use or
disposal method for which POTW qualifies and least costly use or disposal
method for which POTW qualifies post-compliance ($1992/dry metric ton)
PD = percent of sewage sludge disposed
CF = conversion factor for units
2.1.4.1 Assumptions find Caveats
The following major assumptions are used in the economic productivity benefits analysis:
13.4 percent of the POTW sewage sludge generated in the United States is
generated at POTWs that are located too far from agricultural land and
surface disposal sites for these use or disposal practices to be economical.
This percentage of sewage sludge is not associated with benefits from shifts
to surface disposal or land application.
Benefits expected from reduced record-keeping requirements and exemption
from certain sewage sludge management practices are not estimated.
No definitive source of cost-saving differential exists.
overestimate or underestimate the cost differentials.
Analysis may
21
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Sewage sludge use or disposal costs vary by POTW. Actual costs incurred
by POTWs affected by the IWC regulation may differ from those estimates.
»
Due to the unavailability of such data, baseline pollutant loadings from all
industrial sources are not included in the analysis.
2.2 Pollutant Fate and Tniririty
Human and ecological exposure and risk from environmental releases of toxic chemicals
depend largely on toxic potency, inter-media partitioning, and chemical persistence. These factors
are dependant on chemical-specific properties relating to toxicological effects on living organisms,
physical state, hydrophobicity/lipophilicity, and reactivity, as well as the mechanism and media
of release and site-specific environmental conditions.
The methodology used in assessing the fate and toxicity of pollutants associated with IWC
wastewaters is comprised of three steps: (1) identification of pollutants of concern; (2)
compilation of physical-chemical and toxicity data; and (3) categorization assessment. These steps
are described in detail below. A summary of the major assumptions and limitations associated
with this methodology is also presented.
2.2.1 Pollutants of Concern Identification
From 1993 through 1995, EPA conducted three sampling episodes to determine the presence
or absence of priority, conventional, and nonconventional pollutants at IWCs located nationwide.
EPA visited 14 IWCs and collected grab samples of untreated IWC scrubber blowdown water from
12 of the 14 IWCs. EPA also collected samples of wastewater, including influent and effluent
streams at 3 of the 14 IWCs. Most of these samples were analyzed for over 450 analytes to identity
pollutants at these facilities. Using these data, EPA applied two criteria to identify pollutants of
concern. These criteria required concentration levels of 10 times the minimum level, and
concentrations at this level in at least three samples. EPA detected 21 pollutants (10 priority
22
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pollutants, 4 conventional/classical pollutant parameters, and 7 nonconventional pollutants) in waste
streams that met the selection criteria. Seventeen (17) of these pollutants (all metals) are evaluated,
including all of the priority and nonconventional pollutants, to assess their potential fate and toxicity
based on known characteristics of each chemical.
2.2.2 Compilation of Physical-Chemical and Toxicity Data
The chemical specific data needed to conduct the fete and toxicity evaluation for this study
include aquatic life criteria or toxic effect data for native aquatic species, human health reference
doses (RfDs) and cancer potency slope factors (SFs), EPA maximum contaminant levels (MCLs)
for drinking water protection, Henry's Law constants, soil/sediment adsorption coefficients
and bioconcentration factors (BCFs) for native aquatic species:
Sources of the above data include EPA ambient water quality criteria documents and
updates, EPA's Assessment Tools for the Evaluation of Risk (ASTER) and the associated
AQUatic Information REtrieval System (AQUIRE) and Environmental Research Laboratory-
Duluth fathead minnow data base, EPA's Integrated Risk Information System (IRIS), EPA's
1993-1995 Health Effects Assessment Summary Tables (HEAST), EPA's 1991-1996 Superfund
Chemical Data Matrix (SCDM), EPA's 1989 Toxic Chemical Release Inventory Screening Guide,
Syracuse Research Corporation's CHEMFATE data base, EPA and other government reports,
scientific literature, and other primary and secondary data sources. To ensure that the examination
is as comprehensive as possible, alternative measures are taken to compile data for chemicals for
which physical-chemical property and/or toxicity data are not presented in the sources listed
above. To the extent possible, Values are estimated for the chemicals using the quantitative
structure-activity relationship (QSAR) model incorporated in ASTER, or for some physical-
chemical properties, utilizing published linear regression correlation equations.
23
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(a) Aquatic Life Data
Ambient criteria or toxic effect concentration levels for the protection of aquatic life are
obtained primarily from EPA ambient water quality criteria documents and EPA's ASTER. For
several pollutants, EPA has published ambient water quality criteria for the protection of
freshwater aquatic life from acute effects. The acute value represents a maximum allowable 1-
hour average concentration of a pollutant at any time that protects aquatic life from lethality. For
pollutants for which no acute water quality criteria have been developed by EPA, an acute value
from published aquatic toxicity test data or an estimated acute value from the ASTER QSAR
model is used. In selecting values from the literature, measured concentrations from flow-through
studies under typical pH and temperature conditions are preferred. In addition, the test organism
must be a North American resident species of fish or invertebrate. The hierarchy used to select
the appropriate acute value is listed below in descending order of priority.
• National acute freshwater quality criteria;
• Lowest reported acute test values (96-hour LC50 for fish and 48-hour
for daphnids);
Lowest reported LC^ test value of shorter duration, adjusted to estimate a
96-hour exposure period;
Lowest reported LCso test value of longer duration, up to a maximum of 2
weeks exposure; and
Estimated 96-hour LC50 from the ASTER QSAR model.
BCF data are available from numerous data sources, including EPA ambient water quality
criteria documents and EPA's ASTER. Because measured BCF values are not available for
several chemicals, methods are used to estimate this parameter based on the octanol/water partition
coefficient or solubility of the chemical. Such methods are detailed in Lyman et al. (1982).
24
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Multiple values are reviewed, and a representative value is selected according to the following
guidelines:
• Resident U.S. fish species are preferred over invertebrates or estimated
values.
• Edible tissue or whole fish values are preferred over nonedible or viscera
values.
• Estimates derived from octanol/water partition coefficients are preferred
over estimates based on solubility or other estimates, unless the estimate
comes from EPA Criteria Documents.
The most conservative value (i.e., the highest BCF) is selected among comparable candidate
values.
(b) Human Health Data
Human health toxiciry data include chemical-specific RfD for noncarcinogenic effects and
potency SF for carcinogenic effects. RfDs and SFs are obtained first from EPA's IRIS, and
secondarily from EPA's HEAST. The RfD is an estimate of a daily exposure level for the human
population, including sensitive subpopulations, that is likely to be without an appreciable risk of
deleterious noncarcinogenic health effects over a lifetime (U.S. EPA, 1989b). A chemical with
a low RfD is more toxic than a chemical with a high RfD. Noncarcinogenic effects include
systemic effects (e.g., reproductive, immunological, neurological, circulatory, or respiratory
toxicity), organ-specific toxicity, developmental toxicity, mutagenesis, and lethality. EPA
recommends a threshold level assessment approach for these systemic and other effects, because
several protective mechanisms must be overcome prior to the appearance of an adverse
noncarcinogenic effect. In contrast, EPA assumes that cancer growth can be initiated from a
single cellular event and, therefore, should not be subject to a threshold level assessment
approach. The SF is an upper bound estimate of the probability of cancer per unit intake of a
25
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chemical over a lifetime (U.S. EPA, 1989b). A chemical with a large SF has greater potential
to cause cancer than a chemical with a small SF.
Other chemical designations related to potential adverse human health effects include EPA
assignment of a concentration limit for protection of drinking water, and EPA designation as a
priority pollutant. EPA establishes drinking water criteria and standards, such as the MCL, under
authority of the Safe Drinking Water Act (SDWA). Current MCLs are available from IRIS. EPA
has designated 126 chemicals and compounds as priority pollutants under the authority of the
Clean Water Act (CWA).
(c) Physical-Chemical Property Data
Two measures of physical-chemical properties are used to evaluate environmental fate:
Henry's Law constant (HLC) and organic carbon-water partition coefficient
HLC is the ratio of vapor pressure to solubility and is indicative of the propensity of a
chemical to volatilize from surface water (Lyman et al., 1982). The larger the HLC, the more
likely the chemical will volatilize. Most HLCs are obtained from EPA's Office of Toxic
Substances' (OTS) 1989 Toxic Chemical Release Inventory Screening Guide (U.S. EPA, 1989c),
the Office of Solid Waste's (OSW) Superfund Chemical Data Matrix (U.S. EPA, 1994a), or the
quantitative structure activity relationship (QSAR) system (U.S. EPA, 1993), maintained by
EPA's Environmental Research Laboratory (ERL) in Duluth, Minnesota.
. is indicative of the propensity of an organic compound to adsorb to soil or sediment
particles and, therefore, partition to such media. The larger the K^, the more likely the chemical
will adsorb to solid material. Most K^s are obtained from Syracuse Research Corporation's
CHEMFATE data base and EPA's 1989 Toxic Chemical Release Inventory Screening Guide.
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2.2.3 Categorization Assessment
The objective of this generalized evaluation of fate and toxicity potential is to place
chemicals into groups with qualitative descriptors of potential environmental behavior and impact.
These groups are based on categorization schemes derived for:
• Acute aquatic toxicity (high, moderate, or slightly toxic);
• Volatility from water (high, moderate, slight, or nonvolatile);
• Adsorption to soil/sediment (high, moderate, slight, or nonadsorptive); and
• Bioaccumulation potential (high, moderate, slight, or nonbioaccumulative).
Using appropriate key parameters, and where sufficient data exist, these categorization
schemes identify the relative aquatic and human toxicity and bioaccumulation potential for each
chemical associated with IWC wastewater. In addition, the potential to partition to various media
(air, sediment/sludge, or water) and to persist in the environment is identified for each chemical.
These schemes are intended for screening purposes only and do not take the place of detailed
pollutant assessments analyzing all fate and transport mechanisms.
This evaluation also identifies chemicals which: (1) are known, probable, or possible
human carcinogens; (2) are systemic human health toxicants; (3) have EPA human health drinking
water standards; and (4) are designated as priority pollutants by EPA. The results of this analysis
can provide a qualitative indication of potential risk posed by the release of these chemicals.
Actual risk depends on the magnitude, frequency, and duration of pollutant loading; site-specific
environmental conditions; proximity and number of human and ecological receptors; and relevant
exposure pathways. The following discussion outlines the categorization schemes. Ranges of
parameter values defining the categories are also presented.
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(a) Acute Aquatic Toxicity
Key Parameter: Acute aquatic life criteria/LC50 or other benchmark (AT)
Using acute criteria or lowest reported acute test results (generally 96-hour and 48-hour
durations for fish and invertebrates, respectively), chemicals are grouped according to their
relative short-term effects on aquatic life.
Categorization Scheme:
AT < 100
1,000 > AT > 100
AT > 1,000
Highly toxic
Moderately toxic
Slightly toxic
This scheme, used as a rule-of-thumb guidance by EPA's OPPT for Premanufacture Notice
(PMN) evaluations, is used to indicate chemicals that could potentially cause lethality to aquatic
life downstream of discharges.
(b) Volatility from Water
Key Parameter: Henry's Law constant (HLC) (atm-mVmol)
TTT/-I _ Vapor Pressure (atm)
Solubility (mol/m3)
(Eq. 14)
HLC is the measured or calculated ratio between vapor pressure and solubility at ambient
conditions. This parameter is used to indicate the potential for organic substances to partition to
28
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air in a two-phase (air and water) system. A chemical's potential to volatilize from surface water
tcan be inferred from HLC.
Categorization Scheme:
HLC > 10"3
10"3 > HLC > 10'5
10'5 > HLC > 3 x ID'7
HLC.OxlO7'
Highly volatile
Moderately volatile
Slightly volatile
Essentially nonvolatile
This scheme, adopted from Lyman et al. (1982), gives an indication of chemical potential
to volatilize from process wastewater and surface water, thereby reducing the threat to aquatic life
and human health via contaminated fish consumption and drinking water, yet potentially causing
risk to exposed populations via inhalation.
(c) Adsorption to Soil/Sediments
Key Parameter: Soil/sediment adsorption coefficient (K.J
is a chemical-specific adsorption parameter for organic substances that is largely
independent of the properties of soil or sediment and can be used as a relative indicator of
adsorption to such media. K^. is highly inversely correlated with solubility, well correlated with
octanol-water partition coefficient, and fairly well correlated with BCF.
29
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Categorization Scheme:
> 10,000
10,000 > KO, > 1,000
1,000 > K^ > 10
Koc<10
Highly adsorptive
Moderately adsorptive
Slightly adsorptive
Essentially nonadsorptive
This scheme is devised to evaluate substances that may partition to solids and potentially
contaminate sediment underlying surface water or land receiving sewage sludge applications.
Although a high ]£„. value indicates that a chemical is more likely to partition to sediment, it also
indicates that a chemical may be less bioavailable.
(d) Bioaccumulation Potential
Key Parameter: Bioconcentration Factor (BCF)
BCF
Equilibrium chemical concentration in organism (wet weight)
Mean chemical concentration in water
(Eq. 15)
BCF is a good indicator of potential to accumulate in aquatic biota through uptake across
an external surface membrane.
Categorization Scheme:
BCF > 500
500 > BCF > 50
50 > BCF > 5
BCF <5
High potential
Moderate potential
Slight potential
Nonbioaccumulative
30
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This scheme is used to identify chemicals that may be present in fish or shellfish tissues
at higher levels than in surrounding water. These chemicals may accumulate in the food chain and
increase exposure to higher trophic level populations, including people consuming their sport catch
or commercial seafood.
2.2.4 Assumptions and Limitations
The major assumptions and limitations associated with the data compilation and
categorization schemes are summarized in the following two sections.
(a) Data Compilation
If data are readily available from electronic data bases, other primary and
secondary sources are not searched.
Much of the data are estimated and, therefore, can have a high degree of associated
uncertainty.
For some chemicals, neither measured nor estimated data are available for key
categorization parameters. In addition, chemicals identified for this study do not
represent a complete set of wastewater constituents. As a result, this study does
not completely assess IWC wastewater.
(b) Categorization Schemes
• Receiving waterbody characteristics, pollutant loading amounts, exposed
populations, and potential exposure routes are not considered.
• Placement into groups is based on arbitrary order of magnitude data breaks for
several categorization schemes. Combined with data uncertainty, this may lead to
an overstatement or understatement of the characteristics of a chemical.
• Data derived from laboratory tests may not accurately reflect conditions in the
field.
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Available aquatic toxicity and bioconcentration test data may not represent the most
sensitive species.
2.3 Documented Tfrivirnnmental
State environmental agencies are contacted, and State 304(1) Short Lists, State Fishing
Advisories, and published literature are reviewed for evidence of documented environmental
impacts on aquatic life, human health, POTW operations, and the quality of receiving water due
to discharges of pollutants from IWCs. Reported impacts are compiled and summarized by study
site and facility.
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3. DATA SOURCES
3.1 Water Quality Imparts
Readily available EPA and other agency data bases, models, and reports are used in the
evaluation of water quality impacts. The following six sections describe the various data sources
used in the analysis.
3.1.1 Facility-Specific Data
EPA's Engineering and Analysis Division (BAD) provided projected IWC facility effluent
process flows, facility operating days, and pollutant loadings (Appendix A) in May 1997 (U.S. EPA,
1997). For each option, the long-term averages (LTAs) were calculated for each pollutant of concern
based on sampling data. Facilities reported in the 1994 Waste Treatment Industry Phase II:
Incinerator Questionnaire the annual quantity discharged to surface water and POTWs (U.S. EPA,
1994b). The annual quantity discharged (facility flow) was multiplied by the LTA for each pollutant
and converted to the proper units to calculate the loading (in pounds per year) for each pollutant.
The locations of IWC facilities on receiving streams are identified using the U.S.
Geological Survey (USGS) cataloging and stream segment (reach) numbers contained in EPA's
Industrial Facilities Discharge (IFD) data base (U.S. EPA, 1994-1996a). Latitude/longitude
coordinates, if available, are used to locate those facilities and POTWs that have not been assigned
a reach number in IFD. The names, locations, and the flow data for the POTWs to which the
indirect facilities discharge are obtained from the 1994 Waste Treatment Industry Phase II:
Incinerator Questionnaire (U.S. EPA, 1994b), EPA's 1992 NEEDS Survey (U.S. EPA, 1992b),
IFD, and EPA's Permit Compliance System (PCS) (U.S. EPA, 1993-1996). If these sources did
not yield information for a facility, alternative measures are taken to obtain a complete set of
receiving streams and POTWs.
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The receiving stream flow data are obtained from either the W.E. Gates study data or from
measured streamflow data, both of which are contained in EPA's GAGE file (U.S. EPA,
1994-1996b). The W.E. Gates study contains calculated average and low flow statistics based on
the best available flow data and on drainage areas for reaches throughout the United States. The
GAGE file also includes average and low flow statistics based on measured data from USGS
gaging stations. "Dissolved Concentration Potentials (DCPs)" for estuaries and bays are obtained
from the Strategic Assessment Branch of NOAA's Ocean Assessments Division (NOAA/U.S.
EPA, 1989-1991) (Appendix B). Critical Dilution Factors are obtained from the Mixing Zone
Dilution Factors for New Chemical Exposure Assessments (U.S. EPA, 1992a).
3.1.2 Information Used to Evaluate POTW Operations
POTW treatment efficiency removal rates are obtained from a study of 50 well-operated
POTWs, referred to as the "50 POTW Study," September 1982 (U.S. EPA, 1982) (Appendk C).
Due to the large number of pollutants applicable for this industry, additional data from the Risk
Reduction Engineering Laboratory (RREL) data base (now renamed the National Risk Management
Research Laboratory data base) were used to augment the POTW data base for the pollutants for
which the 50 POTW Study did not cover (U.S. EPA, 1995a). When data are not available, the
removal rate is based on the removal rate of a similar pollutant.
Inhibition values are obtained from Guidance Manual for Preventing Interference at
POTWs (U.S. EPA, 1987) and from CERCLA Site Discharges to POTWs: Guidance Manual
(U.S. EPA, 1990a). The most conservative values for activated sludge are used. For pollutants
with no specific inhibition value, a value based on compound type (e.g., aromatics) is used
(Appendix C).
Sewage sludge regulatory levels, if available for the pollutants of concern, are obtained
from the Federal Register 40 CFR Part 503, Standards for the Use or Disposal of Sewage Sludge,
Final Rule (October 25, 1995) (U.S. EPA, 1995b). Pollutant limits established for the final use
34
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or disposal of sewage sludge when the sewage sludge is applied to agricultural and non-
agricultural land are used (Appendix C). Sludge partition factors are obtained from the Report
to Congress on the Discharge of Hazardous Wastes to Publicfy-Owned Treatment Works (Domestic
Sewage Study) (U.S. EPA, 1986) (Appendix C).
3.1.3 Water Quality Criteria (WQC)
The ambient criteria (or toxic effect levels) for the protection of aquatic life and human
health are obtained from a variety of sources including EPA criteria documents, EPA's ASTER,
and EPA's IRIS (Appendix C). Ecological toxicity estimations are used when published values
are not available. The hierarchies used to select the appropriate aquatic life and human health
values are described in the following sections.
3.1.3.1 Aquatic Ltfe
Water quality criteria for many pollutants are established by EPA for the protection of
freshwater aquatic life (acute and chronic criteria). The acute value represents a maximum
allowable 1 -hour average concentration of a pollutant at any time and can be related to acute toxic
effects on aquatic life. The chronic value represents the average allowable concentration of a toxic
pollutant over a 4-day period at which a diverse genera of aquatic organisms and their uses should
not be unacceptably affected, provided that these levels are not exceeded more than once every
3 years.
For pollutants for which no water quality criteria are developed, specific toxicity values
(acute and chronic effect concentrations reported in published literature or estimated using various
application techniques) are used. In selecting values from the literature, measured concentrations
from flow-through studies under typical pH and temperature conditions are preferred. The test
organism must be a North American resident species of fish or invertebrate. The hierarchies used
to select the appropriate acute and chronic values are listed below in descending order of priority.
35 - -
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Acute Aqiiatir. T.ife Values?
• National acute freshwater quality criteria;
• Lowest reported acute test values (96-hour LC50 for fish and 48-hour
EC50/LC50 for daphnids);
• Lowest reported LC50 test value of shorter duration, adjusted to estimate a
96-hour exposure period;
• Lowest reported UCX test value of longer duration, up to a maximum of 2
weeks exposure; and
• Estimated 96-hour LC50 from the ASTER QSAR model.
Oimnif; Aquatic TJfe Vainest
• National chronic freshwater quality criteria;
• Lowest reported maximum allowable toxic concentration (MATC), lowest
observable effect concentration (LOEC), or no observable effect
concentration (NOEC);
• Lowest reported chronic growth or reproductive toxicity test concentration;
and
• Estimated chronic toxicity concentration from a measured acute chronic
ratio for a less sensitive species, QSAR model, or default acute: chronic
ratio of 10:1.
3.1.3.2 Human Health
Water quality criteria for the protection of human health are established in terms of a
pollutant's toxic effects, including carcinogenic potential. These human health criteria values are
developed for two exposure routes: (1) ingesting the pollutant via contaminated aquatic organisms
only, and (2) ingesting the pollutant via both water and contaminated aquatic organisms as
follows.
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For Tenacity Protection (ingestion of organisms only)
= RJD x CF
00 IRjX BCF
(Eq. 16)
where:
RfD =
BCF =
CF
human health value 0/g/L)
reference dose for a 70-kg individual (mg/day)
fish ingestion rate (0.0065 kg/day)
bioconcentration factor (liters/kg)
conversion factor for units (1,000
For Carcinogenic Protection (ingesfinn of organisms only)
„„ BWxRLxCF
tin = '
00 SFxIRfxBCF
(Eq.17)
where:
BW
RL
SF
IR,
BCF
CF
human health value
body weight (70 kg)
risk level (10-6)
cancer slope factor (mg/kg/day)"1
fish ingestion rate (0.0065 kg/day)
bioconcentration factor (liters/kg)
conversion factor for units (1,000
For Toxicitv Protection Cingestion of urater and nrcranismsV
RJDx CF
IRW + (IRfxBCF)
(Eq. 18)
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where:
HH,,,, =
RfD =
BCF =
CF =
human health value
reference dose for a 70-kg individual (mg/day)
water ingestion rate (2 liters/day)
fish ingestion rate (0.0065 kg/day)
bioconcentration factor (liters/kg)
conversion factor for units (1000 y^g/mg)
Fnr Carcinogenic Protection (ingestinn of water anri organisms)
BWxRLx CF
SFx(IRw + (IRfxBCF))
(Eq. 19)
where:
HHWO
BW
RL
SF
BCF
CF
human health value
body weight (70 kg)
risk level (KT6)
cancer slope factor (mg/kg/day)"1
water ingestion rate (2 liters/day)
fish ingestion rate (0.0065 kg/day)
bioconcentration factor (liters/kg)
conversion factor for units (1,000 /ig/rng)
The values for ingesting water and organisms are derived by assuming an average daily ingestion
of 2 liters of water, an average daily fish consumption rate of 6.5 grams of potentially
contaminated fish products, and an average adult body weight of 70 kilograms (U.S.
EPA, 1991a). Values protective of carcinogenicity are used to assess the potential effects on
human health, if EPA has established a slope factor.
Protective concentration levels for carcinogens are developed in terms of non-threshold
lifetime risk level. Criteria at a risk level of 10"6 (1E-6) are chosen for this analysis. This risk
38
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level indicates a probability of one additional case of cancer for every 1-million persons exposed.
Toxic effects criteria for noncarcinogens include systemic effects (e.g., reproductive,
immunological, neurological, circulatory, or respiratory toxicity), organ-specific toxicity,
developmental toxicity, mutagenesis, and lethality.
The hierarchy used to select the most appropriate human health criteria values is listed
below in descending order of priority:
Calculated human health criteria values using EPA's IRIS RfDs or SFs used in
conjunction with adjusted 3 percent lipid BCF values derived from Ambient Water
Quality Criteria Documents (U.S. EPA, 1980); three percent is the mean lipid
content of fish tissue reported in the study from which the average daily fish
consumption rate of 6.5 g/day is derived;
Calculated human health criteria values using current IRIS RfDs or SFs and
representative BCF values for common North American species of fish or
invertebrates or estimated BCF values;
Calculated human health criteria values using RfDs or SFs from EPA's HEAST
used in conjunction with adjusted 3 percent lipid BCF values derived from Ambient
Water Quality Criteria Documents (U.S. EPA, 1980);
Calculated human health criteria values using current RfDs or SFs from HEAST
and representative BCF values for common North American species of fish or
invertebrates or estimated BCF values;
Criteria from the Ambient Water Quality Criteria Documents (U.S. EPA, 1980);
and
Calculated human health values using RfDs or SFs from data sources other than
IRIS or HEAST.
This hierarchy is based on Section 2.4.6 of the Technical Support Document for Water
i
Quality-based Toxics Control (U.S. EPA, 1991a), which recommends using the most current risk
information from IRIS when estimating human health risks. In cases where chemicals have both
RfDs and SFs from the same level of the hierarchy, human health values are calculated using the
39
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formulas for cartinogenitity, which always result in the more stringent value of the two given the
risk levels employed.
3.1.4 Information Used to Evaluate Human Health Risks and Benefits
Fish ingestion rates for sport anglers, subsistence anglers, and the general population are
obtained from the Exposure Factors Handbook (U.S. EPA, 1989a). State population data and
»
average household size are obtained from the 1995 Statistical Abstract of the United States (U.S.
Bureau of the Census, 1995). Data concerning the number of anglers in each State (i.e., resident
fishermen) are obtained from the 1991 National Survey of Fishing, Hunting, and Wildlife
Associated Recreation (U.S. FWS, 1991). The total number of river miles or estuary square miles
within a State are obtained from the 1990 National Water Quality Inventory - Report to Congress
(U.S. EPA, 1990b). Drinking water utilities located within 50 miles downstream from each
discharge site are identified using EPA's PATHSCAN (U.S. EPA, 1996a). The population served
by a drinking water utility is obtained from EPA's Drinking Water Supply Files (U.S. EPA,
1996b) or Federal Reporting Data System (U.S. EPA, 1996c). Willingness-to-pay values are
obtained from OPA's review of a 1989 and a 1986 study The Value of Reducing Risks of Death:
A Note on New Evidence (Fisher, Chestnut, and Violette, 1989) and Valuing Risks: New
Information on the Willingness to Pay for Changes in Fatal Risks (Violette and Chestnut, 1986).
Values are adjusted to 1992, based on the relative change in the Employment Cost Index of Total
Compensation for all Civilian Workers. Information used in the evaluation is presented in
Appendix D.
3.1.5 Information Used to Evaluate Ecological Benefits
The concept of a "contaminant-free fishery" and the estimate of an increase in the
consumer surplus associated with a contaminant-free fishery are obtained from Discrete Choice
Models to Value Changes in Environmental Quality: A Great Lakes Case Study, a thesis submitted
at the University of Wisconsin-Madison by Audrey Lyke in 1993. Data concerning the number
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of resident anglers in each State and average number of fishing days per angler in each State are
obtained from the 1991 National Survey of Fishing, Hunting, and Wildlife Associated Recreation
(U.S. FWS, 1991) (Appendix D). Median net benefit values for warm water and cold water
fishing days are obtained from Nonmarket Values from Two Decades of Research on Recreational
Demand (Walsh et al., 1990). Values are adjusted to 1992, based on the change in the Consumer
Price Index for all urban consumers, as published by the Bureau of Labor Statistics.
3.1.6 Information Used to Evaluate Economic Productivity Benefits
Sewage sludge pollutant limits for surface disposal and land application (ceiling limits and
pollutant concentration limits) are obtained from the Federal Register 40 CFR Part 503, Standards
for the Use or Disposal of Sewage Sludge, Final Rule (October 25, 1995) (U.S. EPA, 1995b).
Cost savings from shifts in sludge use or disposal practices from composite baseline disposal
practices are obtained from the Regulatory Impact Analysis of Proposed Effluent Limitations
Guidelines and Standards for the Metal Products and Machinery Industry (Phase I) (U.S. EPA,
1995c). Savings are adjusted to 1992 using the Construction Cost Index published in the
Engineering News Record. In this report, EPA consulted a wide variety of sources, including:
• 1988 National Sewage Sludge Survey;
• 1985 EPAHandbook for Estimating Sludge Management Costs',
• 1989 EPA Regulatory Impact Analysis of the Proposed Regulations for Sewage
Sludge Use and Disposal;
• Interviews with POTW operators;
• Interviews with State government solid waste and waste pollution control experts;
• Review of trade and technical literature on sewage sludge use or disposal practices
and costs; and
• Research organizations with expertise in waste management.
41
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Information used in the evaluation is presented in Appendix D.
3.2 Pollutant Fate and
The chemical-specific data needed to conduct the fate and toxicity evaluation are obtained
from various sources as discussed in Section 2.2.2 of this report. Aquatic life and human health
values are presented in Appendix C. Physical/chemical property data are also presented in
Appendix C.
3.3 Dnrnmentpd F.nvirnnmentfll Tmparfs
Data are obtained from State environmental agencies in Regions I, n, IE, and IV. Data
are also obtained from the 1990 State 304(1) Short Lists (U.S. EPA, 1991b) and the 1995 National
Listing of Fish and Wildlife Consumption Advisories (U.S. EPA, 1995d). Literature abstracts are
obtained through the computerized information system DIALOG (Knight-Ridder Information,
1996), which provides access to Enviroline, Pollution Abstracts, Aquatic Science Abstracts, and
Water Resources Abstracts.
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4. SUMMARY OF RESULTS
4.1 Projected Water Quality Imparts
4.1.1 Comparison of Instream Concentrations with Ambient Water Quality Criteria
The results of this analysis indicate the water quality benefits of controlling discharges
from IWC facilities to surface waters and POTWs. The following two sections summarize
potential aquatic life and human health impacts on receiving stream water quality and on POTW
operations and their receiving streams for direct and indirect discharges. All tables referred to in
these sections are presented at the end of Section 4. Appendices E, F, and G present the results
of the stream modeling for each type of discharge, respectively.
4.1.1.1 Direct Discharges
The effects of direct wastewater discharges on receiving stream water quality are evaluated
at current and proposed BAT treatment levels for 8 facilities discharging 17 pollutants (metals)
to 8 receiving streams (8 rivers) (Table 1). At current discharge levels, these 8 facilities
discharge 23,532 pounds-per-year of metals (Table 2). These loadings are reduced to 16,765
pounds-per-year at proposed BAT levels; a 29 percent reduction.
Modeled instream pollutant concentrations are projected to exceed human health criteria
or toxic effect levels (developed for water and organisms consumption) in 50 percent (4 of the
total 8) of the receiving streams at current and proposed BAT discharge levels (Table 3). A total
of 2 pollutants at current and 1 pollutant at proposed RAT discharge levels are projected to
exceed instream human health criteria or toxic effect levels using a target risk of 10"* (1E-6) for
carcinogens (Table 4).
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Ihstream pollutant concentrations are projected to exceed chronic qqnatic life criteria or
toxic effect levels in 50 percent (4 of the total 8) of the receiving streams at current discharge
levels (Table 3). A total of 8 pollutants at current are projected to exceed instream criteria or
toxic effect levels (Table 4). Proposed BAT discharge levels reduce projected excursions to 7
pollutants in the 4 receiving streams (Tables 3 and 4).
Excursions of human health criteria or toxic effect levels (developed for organisms
consumption only) and of acute aquatic life criteria or toxic effect levels are also presented in
Table 3. A similar reduction in the number of pollutants exceeding criteria is noted.
4.1.1.2 Indirect Discharges
The effects of POTW wastewater discharges of 17 pollutants (metals) on receiving stream
water quality are evaluated at current and proposed pretreatment discharge levels, for
3 facilities, which discharge to 3 POTWs located on 3 receiving streams (2 rivers and 1 estuary)
(Table 1). Pollutant loadings for 3 facilities at current discharge levels are 48,574 pounds-per-
year (Table 2). The loadings are reduced to 1,298 pounds-per-year after prelrealmenl; a
reduction of 97 percent.
Instream pollutant concentrations are projected to exceed human health criteria or toxic
effect levels (developed for water and organisms consumption) in 33 percent (1 of the total 3) of
the receiving streams at current, discharge levels (Table 5). A total of 1 pollutant at current is
projected to exceed instream criteria or toxic effect levels using a target risk of 10"6 (1E-6) for the
carcinogens (Table 6). No excursions of human health criteria or toxic effect levels are
projected at proposed pretreatment discharge levels. A similar reduction in the number of
pollutants and streams exceeding human health criteria or toxic effect levels (developed for
organism consumption only) is noted (Table 5).
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Instream pollutant concentrations of 1 pollutant are projected to exceed chrnnip
life criteria or toxic effect levels at current discharge levels in 33 percent (1 of the total 3) of the
receiving streams (Tables 5 and 6). No excursions of chronic aqnaf !<• life criteria or toxic effect
levels are projected at proposed pretrpafment discharge levels. No excursions of ap«te
life criteria or toxic effect levels are projected at current or proposed prptrpatmpnt discharge
levels (Table 5).
In addition, the potential impact of 3 facilities, which discharge to 3 POTWs, are evaluated
in terms of inhibition of POTW operation and contamination of sludge. Inhibition problems and
sludge contamination problems are projected at current discharge levels only (Table 7).
Inhibition problems are projected to occur at 33 percent (1 of the 3) of the POTWs from 1
pollutant (Tables 7 and 8). Sludge contamination is projected to occur at 67 percent (2 of the 3)
of the POTWs due to 3 pollutants (Tables 7 and 8) .
4.1.2 Estimation of Human Health Risks and Benefits
The results of mis analysis indicate the potential benefits to human health by estimating the
risks (carcinogenic and systemic effects) associated with current and reduced pollutant levels in
fish tissue and drinking water. The following two sections summarize potential human health
impacts from the consumption of fish tissue and drinking water derived from waterbodies
impacted by direct and indirect discharges. Risks are estimated for recreational (sport) and
subsistence anglers and their families, as well as the general population. Appendices H and I
present the results of the modeling for each type of discharge, respectively!
4.1.2.1 Direct Discharges
The effects of direct wastewater discharges on human health from the consumption of fish
tissue and drinking water are evaluated at current and proposed BAT treatment levels for 8
facilities discharging 17 pollutants (metals) to 8 receiving streams (8 rivers) (Table 1).
45
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(a) fish Tissue
At current and proposed BAT discharge levels, 4 streams have total estimated individual
pollutant cancer risks greater than 10* (1E-6) due to the discharge of 1 carcinogen from 4 facilities
(Tables 9 and 10). Total estimated risks greater than 10* (1E-6) are projected for the general
population, sport: anglerSj and subsistence anglers. At current discharge levels, total excess
annual cancer cases are estimated to be 5.7E-3 (Table 9). Total excess annual cancer cases are
reduced to 3.0E-3 at proposed BAT levels (Table 9). Because the number of excess annual
cancer cases at current discharge levels is less than 0.5, a monetary value of benefits to society
from avoided cancer cases is not estimated.
Systemic toxicant effects (hazard index greater than 1.0) are projected for only subsistence
anglers in 3 receiving streams from 3 pollutants at current, discharge levels (Table 11). An
estimated population of 705 subsistence anglers and their families are projected to be affected.
The proposed BAT discharge level will reduce the systemic toxicant effects to 1 receiving stream
and 1 pollutant affecting an estimated population of 373 subsistence anglers and their families
(Table 11). A monetary value of benefits to society could not be estimated.
(b) Drinking Water
At current, and proposed BAT discharge levels, 4 streams have total estimated individual
pollutant cancer risks greater than 10* (1E-6) due to the discharge of 1 carcinogen from 4 facilities
(Table 12). Estimated risks range from 5.2E-6 to 3.0E-5 at current and from 1.8E-6 to 1.7E-5
at proposed BAT. However, no drinking water utility is located within 50 miles downstream of
any of the discharge sites (i.e., total excess annual cancer cases are not projected). The hazard
index exceeds 1.0 in one receiving stream at current discharge levels only (Table 11). However,
systemic toxicant effects are not projected, because no drinking water utility is located within 50
miles downstream.
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4.1.2.2 Indirect Discharges .
The effects of POTW wastewater.discharges on human health from the consumption of fish
tissue and drinking water are evaluated at current and prnpnspfl pretreatmpnt discharge levels
for 3 facilities that discharge 17 pollutants (metals) to 3 POTWs on 3 receiving streams (2 rivers
and 1 estuary) (Table 1).
(a) Fish Tissue
At rniTpnf discharge levels, 1 stream, receiving the discharge from 1 facility, has a total
estimated individual pollutant cancer risk greater than 10"6 (1E-6) from 1 carcinogen (Tables 13
and 14). Total estimated risks greater than 10"6 (1E-6) are projected for the general population
sport anglers, and .subsistence anglers. Total excess annual cancer cases are estimated at 7.7E-3.
At proposed pretreatment levels, no streams are projected to have a total estimated individual
cancer risk greater than 10* (1E-6) (Table 13). Because the number of excess annual cancer cases
at current discharge levels is less than 0.5, a monetary value of benefits to society from avoided
cancer cases is not estimated.
Systemic toxicant effects (hazard index greater than 1.0) are projected at currant discharge
levels for subsistence anglers only due to the discharge of 2 pollutants to 1 receiving stream (Table
15). An estimated population of 249 subsistence anglers and their families are projected to be
affected. No systemic toxicant effects are projected at proposed pretreatment levels (Table 15).
A monetary value of benefits to society could not be estimated.
(b) Drinking Water
At current discharge levels, 1 stream has a total estimated individual pollutant cancer risk
greater than 10"* (1E-6) due to the discharge of 1 carcinogen from 1 facility (Table 16). The
estimated risk is 1.4E-4. However, no drinking water utility is located within 50 miles
47
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downstream of the discharge site (i.e., total excess annul cancer cases are not projected). At
proposed pretreatment levels, no streams are projected to have a total estimated individual
cancer risk greater than 10"6 (1E-6) (Table 16). In addition, no systemic toxicant effects (hazard
index greater than 1.0) are projected at mrrgnt or proposed pretreatmenf levels (Table 15).
4.1.3 Estimation of Ecological Benefits
The results of this analysis indicate the potential ecological benefits of the proposed
regulation by estimating improvements in the recreational fishing habitats that are impacted by
direct and indirect IWC wastewater discharges. Such impacts include acute and chronic toxicity,
sublethal effects on metabolic and reproductive functions, physical destruction of spawning and
feeding habitats, and loss of prey organisms. These impacts will vary due to the diveristy of
species with differing sensitivities to impacts. For example, lead exposure can cause spinal
deformities in rainbow trout. Copper exposure can affect the growth activity of algae. In
addition, copper and cadmium can be acutely toxic to aquatic life, including finfish. The
following sections summarize the potential monetary benefits for direct and indirect discharges
as well as additional benefits that are not monetized. Appendices H and I present the results of
the analyses for each type of discharge, respectively.
4.1.3.1 Direct Discharges
The effects of direct wastewater discharges on aquatic habitats are evaluated at current and
BAT treatment levels for 8 facilities discharging 17 pollutants (metals) to 8 receiving
streams (Tables 1 and 3). Because the proposed regulation is not estimated to completely
eliminate instream concentrations in excess of AWQC, no benefits to recreational (sport) anglers,
based on improved quality and improved value of fishing opportunities, are estimated.
48
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4.1.3.2 Indirect Discharges
The effects of indirect wastewater discharges on aquatic habitats are evaluated at current
and proposed prctreafmenf levels for 3 facilities that discharge 17 pollutants to 3 POTWs located
on 3 receiving streams (Tables 1 and 5). Concentrations in excess of AWQC are projected to be
eliminated at 1 receiving stream as a result of the proposed regulation. The monetary value of
improved recreational fishing opportunity is estimated by first calculating the baseline value of the
benefiting stream segment (Table 17). From the estimated total of 25,517 person-days fished on
the stream segment, and the value per person-day of recreational fishing ($27.75 and $35.14, 1992
dollars), a baseline value of $708,000 to $897,000 is estimated for the 1 stream segment. The
value of improving water quality in this fishery, based on the increase in value (11.1 percent to
31.3 percent) to anglers of achieving a contaminant-free fishing (Lyke, 1993), is then calculated.
The resulting estimate of the increase in value of recreational fishing to anglers ranges from
$78,600 to $281,000.
4.1.2.3 Additional Ecological Benefits .
As noted in Section 2.1.3.1, the estimated benefit of improved recreational fishing
opportunities is only a limited measure of the value to society of the improvements in aquatic
habitats expected to result from the proposed regulation. Additional ecological benefits include
protection of terrestrial wildlife and birds that consume aquatic organisms. The proposed
regulation will also result in a reduction in the presence and discharge of toxic pollutants, thereby
protecting those aquatic organisms currently under stress, providing the opportunity for the re-
establishment of productive ecosystems in damaged waterways, and protection of resident
endangered species. In addition, recreational activities, such as boating, water skiing, and
swimming, will also be preserved along with the maintenance of an asthetically pleasing
environment. Such activities contribute to the support of local and State economies.
49
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4.1.4 Estimation of Economic Productivity Benefits
The results of this analysis indicate the potential productivity benefits of the proposed
regulation based on reduced sewage sludge contamination at POTWs receiving the discharges from
indirect IWC facilities. As a result of the proposed regulation, 1 POTW will meet land
application pollutant concentration limits. Estimated disposal cost differentials are used to
calculate cost-savings values (Table 18). Based on cost savings of $23/DMT, benefits are
estimated at $7,400 annually (1992 dollars). In addition, 2 POTWs (1 additional) are expected
to accrue a modest benefit through reduced record-keeping requirements and exemption from
certain sewage sludge management practices. A monetary value for these modest benefits could
not be estimated. Appendix I presents the results of the analysis.
4.2 Pplliitant Fafp and Tniricity
Human exposure, ecological exposure, and risk from environmental releases of toxic
chemicals depend largely on toxic potency, inter-media partitioning, and chemical persistence.
These factors are dependent on chemical-specific properties relating to toxicological effects on
living organisms, physical state, hydrophobicity/lipophilicity, and reactivity, as well as the
mechanism and media of release and site-specific environmental conditions. Based on available
physical-chemical properties, and aquatic life and human health toxicity data for the 17 evaluated
pollutants (metals), 10 exhibit moderate to high toxicity to aquatic life; 13 are human systemic
toxicants; 3 are classified as known or probable human carcinogens; 13 have drinking water values
(6 with enforceable health-based MCLs), 5 with secondary MCLs for asthetics or taste, and 2 with
action levels for treatment); and 10 are designated by EPA as priority pollutants (Tables 19, 20,
and 21). In terms of projected environmental partitioning among media, only 1 of the evaluated
pollutants is moderately to highly volatile (potentially causing risk to exposed populations via
inhalation); and 4 have a moderate to high potential to bioaccumulate in aquatic biota (potentially
accumulating in the food chain and causing increased risk to higher trophic level organisms and
to exposed human populations via fish and shellfish consumption). All of the pollutants are
50
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metals, which, in general, are not applicable to evaluation based on volatility and adsorption to
solids. It is assumed that all of the metals have a high potential to sorb to solids.
4.3 Documented Fnvirnnmpntal Tmpapfs
literature abstracts, State 304(1) Short Lists, and State fishing advisories are reviewed for
documented impacts due to discharges from IWC facilities. Two (2) direct IWC facilities and 2
POTWs receiving wastewater from 2 IWC facilities are identified by States as being point sources
causing water quality problems and are included on their 304(1) Short List (Tables 22 and 23).
Section 304(1) of the Water Quality Act of 1987, which requkes States to identify waterbodies
impaired by the presence of toxic substances, to identify point-source discharges of these toxics,
and to develop Individual Control Strategies (ICSs) for these discharges. The Short List is a list
of waters for which a State does not expect applicable water quality standards (numeric or
narrative) to be achieved after technology-based requirements are met due entirely or substantially
to point source discharges of Section 307(a) toxics. State contacts indicate that of the two direct
facilities, one is no longer in operation, and the other is currently in compliance with its permit
limits and is no longer a source of impairment. Both POTWs listed are also currently in
compliance for the listed pollutants. In addition, two IWC facilities are located on waterbodies
with State-issued fish consumption advisories. However, the advisories are based on dioxins,
which are not a pollutant of concern for the IWC industry.
51
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Table 1. Evaluated Pollutants of Concern Discharged from 8 Direct
and 3 Indirect IWC Facilities
CASKutaber '
7429905
7440360
7440382
7440428
7440439
7440473
7440508
7439896
7439921
7439965
7439976
7439987
7782492
7440224
7440315
7440326
7440666
Pollutant Hame
Aluminum
Antimony
Arsenic*
Boron
Cadmium*
Chromium*
Copper*
Iron
Lead*
Manganese
Mercury*
Molybdenum
Selenium
Silver*
Tin
Titantium*
Zinc*
* Proposed for regulation
Source: Engineering and Analysis Division (BAD), May 1997.
July 24, 1997
52
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-------
Table 17. Summary of Ecological (Recreational) Benefits for Indirect IWC Dischargers
(National Basis)
Number of Stream Segments
•with Concentrations -- "
Exceeding AWQC Eliminated.
1
Total Fishing
Days
25,517
Baseike Value of
Fishery ($1992)
$708,000-$897,000
Increased Value of
! Fishery ($1992)
$78,600-$28 1,000
NOTE: Value per person day of recreational fishing = $27.75 (warm water) and $35.14 (cold
water).
Increase value of contaminant-free fishing = 11.1 to 31.3 percent.
July 24, 1997
68
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Table 18. Cost Savings from Shifts in Sludge Use or Disposal Practices from
Composite Baseline Disposal Practices (1992S/DMT)
., -.V" -f
I A^xwiedBaseu^POTWMix
cf Sewage Sludge Use or
Disposal Practices '
Meet surface disposal pollutant
limits; do not meet land
application ceiling pollutant
limits
Assumed disposal mix:
47% dedicated site
28% monofills
25% surface impoundment
Do not meet land application
pollutant limits or surface
disposal pollutant limits
Assumed disposal mix:
32% incineration
68% co-disposal
Post-Compliance POTW Sewage Slaiigetfe? or Disposal Practice
Agricultural Application
{86.6 percent of sewage
stodge thatmeetsWd -"
application pollutant
, limits)
$0-523
$94-$202
Bagged Sewage Sludge
{13.4 percent of sewage
sludge lhaf Bieete land
application pollutant
limits)
$0
$0-$32
Surface Disposal* i
{Meet surface pollutant \
limits; do not meet land :
appucafioa pollutant
limits) :
N/A
$32-8202
* Surface disposal includes monofills, surface impoundments, and dedicated sites.
Source: U.S. Environmental Protection Agency, 1995b.
69
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Table 20. Toxicants Exhibiting Systemic and Other Adverse Effects*'
i Toxicant
Antimony
Arsenic
Boron
Cadmium
Chromium
Lead***
Manganese
Mercury
Molybdenum '.
Selenium
Silver
Tin
Zinc
Reference Dose Target Organ and Effects
Longevity, blood glucose, cholesterol
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Testicular atrophy, spermatogenic arrest
Significant proteinuria
No adverse effects observed**
Cardiovascular and CNS effects
CNS effects
CNS effects
Increased uric acid
^
Clinical selenosis (hair or nail loss), liver dysfunction
Argyria (skin discoloration)
Kidney and liver lesions
Anemia
**
***
Chemicals with EPA verified or provisional human health-based reference doses, referred
to as "systemic toxicants."
Reference dose based on a no observed adverse effect level (NOAEL).
Pollutant has no reference dose; however, EPA criterion for systemic toxicity protection
has been assigned.
71
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Table 21. Human Carcinogens Evaluated, Weight-of-Evidence
Classifications, and Target Organs
Carcinogen
Arsenic
Cadmium
Lead
Weigat-o£Evideace Classification
A
Bl
B2
Target Organs
Skin and lung
Lung, tracheae, and bronchus
Kidney, stomach, and lung
A Human Carcinogen
B1 Probable Human Carcinogen (limited human data)
B2 Probable Human Carcinogen (animal data only)
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R-4
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