United States Prevention, Pesticides EPA738-R-00-010
Environmental Protection And Toxic Substances September 2000
Agency (7508C)
&EPA Rere9istration Eligibility
Decision Addendum and
FQPA Tolerance
Reassessment Progress
Report
Coumaphos
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United States
Environmental Protection
Agency
Prevention, Pesticides
and Toxic Substances
(7508C)
EPA 738-F-00-008
September 2000
Coumaphos Facts
EPA has reassessed the risks of coumaphos and reached a Reregisttation Eligibility Decision
(RED) on the uses of coumaphos where a decision was deferred in the 1996 Coumaphos RED. In
1996, a reregistration decision was only reached for the dip vat use by the U.S. Department of
Agriculture. In this RED Addendum, EPA has determined that if the risk mitigation measures for Ms
organophosphate (OP) pesticide are adopted, coumaphos fits into its own "risk cup"- its individual,
aggregate risks are within acceptable levels. Coumaphos also is eligible for reregistration, pending a full
reassessment of the cumulative risk from all OPs.
Used on livestock (beef and dairy cattle,
horses, goats, sheep and swine) and swine
bedding for the control of arthropod pests,
coumaphos residues in food and drinking water
do not pose risk concerns. With mitigation
limiting exposure to workers who handle this
pesticide, coumaphos fits into its own "risk
cup." With other mitigation measures,
groundwater sources of drinking water could be
further protected from potential pesticide
contamination.
EPA's next step under the Food Quality
Protection Act (FQPA) is to complete a
cumulative risk assessment and risk
management decision encompassing all the OP
pesticides, which share a common mechanism
of toxicity. The interim decision on coumaphos
cannot be considered final until this cumulative
assessment is complete. Further risk mitigation
may be warranted at that time.
EPA is reviewing the OP pesticides to
determine whether they meet current health arid
safety standards. Older OPs need decisions about their eligibility for reregistration under FIFRA. OPs
with residues in food, drinking water, and other non-occupational exposures also must be reassessed to
make sure they meet the new FQPA safety standard.
The OP Pilot Public Participation Process
The organophosphatesare a group of
related pesticides that affect the functioning of the
nervous system. They are among EPA's highest
priority for review under the Food Quality Protection
Act.
EPA is encouraging the public to
participate in the review of the OP pesticides.
Through a six-phased pilot public participation
process, the Agency is releasing for review and
comment its preliminary and revised scientific risk
assessments for individual OPs. (Please contact
the OP Docket, telephone 703-305-5805, or see
EPA's web site, www.epa.gov/pesticides/op.)
EPA is exchanging information with
stakeholders and the public about the OPs, their
uses, and risks through Technical Briefings,
stakeholder meetings, and other fora. USDA is
coordinating input from growers and other OP
pesticide users.
Based on current information from
interested stakeholders and the public, EPA is
making interim risk management decisions for
individual OP pesticides, and will make final
decisions through a cumulative OP assessment.
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The coumaphos reregistration eligibility decision was made through the OP pilot public
participation process, which increases transparency and maximizes stakeholder involvement in EPA's
development of risk assessments and risk management decisions. EPA worked extensively with
affected parties to reach the decisions presented in this interim decision document, which concludes the
OP pilot process for coumaphos.
Uses
An insecticide/acaricide, coumaphos is used to control flies, ticks, and mites, among other
arthropod pests on livestock and swine bedding. Predominant use is on beef cattle.
Coumaphos is an important tool in the USDA Cattle Fever Tick Eradication Program (dip vat
treatment) to prevent the reintroduction of equine and bovine piroplasmosis into the U.S.
Emergency exemptions exist for coumaphos use in bee hives to control varroa mites and small
hive beetles.
Estimated annual domestic use is very low- approximately 71,000 pounds of active ingredient
per year.
Health Effects
Coumaphos can cause cholinesterase inhibition in humans; that is, it can overstimulate the
nervous system causing nausea, dizziness, confusion, and at very high exposures (e.g., accidents
or major spills), respiratory paralysis and death.
Risks
Dietary exposures from eating commodities treated with coumaphos are not of concern for the
entire U.S. population, including infants and children. Drinking water is not a significant source
ofexposure.
Coumaphos is not registered for use in residential areas, therefore residential risks were not
assessed.
Risks are of concern for workers who mix, load, and apply coumaphos to livestock and swine
bedding.
Environmental risks were not reassessed because the Agency has no reason to believe the
conclusions would change since the 1996 RED was issued.
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Risk Mitigation
In order to support a reregistration eligibility decision for coumaphos, the Mowing risk
mitigation measures are necessary:
To mitigate risks to workers:
For dip vat use:
Restrict the use of the 42% flowable product to U.S. Department of Agriculture
(USDA-APfflS) stafFenrolled in the USDA-APHIS cholinesterase monitoring
program.
For spray uses:
Maintain the current use restriction limiting the number of animals an individual can treat
using hand-held sprayers to 100 head per day at the maximum application rate and
move this restriction to a more prominent place on the labels.
For dust uses:
Prohibit the use of mechanical dusters as a method of application for coumaphos
technical, all manufacturing-use products and all end-use products;
Require the use of a dust/mist respirator and a chemical-resistant apron; and
Limit the number of animals an individual may treat using a shaker can to 25 head per
day and the swine bedding area to be treated to 1,000 sq. ft. per day.
To further mitigate any potential ground water contamination:
Restrict the disposal of bioremediated coumaphos spent solution from dip vat
operations to shallow, concrete-lined evaporation ponds.
To reflect the uses currently supported by the technical registrant:
Restrict the formulation of coumaphos products for use on beef cattle, dairy cattle,
horses, swine and swine bedding use only.
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Next Steps
Numerous opportunities for public comment were offered as this decision was being
developed. The Coumaphos RED Addendum therefore is issued in final (see
www.epa.gov/REDs/ or www.epa.gov/pesticides/op ), without a formal public comment
period. The docket remains open, however, and any comments submitted in the future will be
placed in this public docket.
To effect risk mitigation as quickly as possible, time frames for making the changes described in
the Coumaphos RED Addendum are shorter than those in a usual RED. All labels need to be
amended to include the above mitigation and submitted to the Agency within 90 days after
issuance of this RED Addendum.
When the cumulative risk assessment for all organophosphate pesticides is completed, EPA will
issue its final tolerance reassessment decision for coumaphos and may request further risk
mitigation measures. The Agency expects to revoke six tolerances for residues in meat, fat, and
meat byproducts of goats and sheep, because the technical registrant no longer supports these
uses and will request voluntary cancellation of these uses. For all OPs, raising and/or
establishing tolerances will be considered once a cumulative assessment is completed.
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
OFFICE OF
PREVENTION, PESTICIDES
AND TOXIC SUBSTANCES
CERTIFIED MATT,
OCT 2 4 2000
Dear Registrant:
This is to inform you that the Environmental Protection Agency has completed its review of the
available data and public comments related to the revised human health risk assessment for the
organophosphate (OP) pesticide coumaphos. Due to the relatively low volume use of coumaphos
compared to other organophosphates, the Agency determined that a technical briefing was not
necessary for this chemical. During Phase 5 of the OP pilot public participation process, all interested
parties were invited to participate and provide comments and suggestions on ways the Agency might
mitigate the estimated risks presented in the revised risk assessment. This public participation and
comment period commenced on April 26,2000, and closed on June 26,2000. The attached
document entitled, "Reregistration Eligibility Decision Addendum and FQPA Tolerance Reassessment
Progress Report for Coumaphos," which was approved on September 27,2000, summarizes the
Agency's assessment of the dietary and occupational risks from coumaphos. Based on its review and
public comments, EPA has identified risk mitigation measures believed necessary to address the human
health risks associated with the current use of coumaphos. These risk mitigation measures can be found
in the attached document.
The major means by which the Agency reassesses tolerances is through its reregistration
process. Each pesticide registered prior to 1984 is subject to a comprehensive evaluation of its effects
on human health and the environment Such an evaluation includes a determination of whether the
tolerances are safe. Since coumaphos was first registered in 1958, it is subject to reregistration. The
Agency issued a Reregistration Eligibility Decision (RED) document for coumaphos in 1996, prior to
the passage of the Food Quality Protection Act of 1996 (FQPA). However, coumaphos tolerances
are subject to reassessment in accordance with the Federal Food, Drug, and Cosmetic Act (FFDCA)
as amended by FQPA. This Act requires EPA to re-evaluate existing tolerances to ensure that children
and other sensitive populations are protected from pesticide risk. The tolerance reassessment decision
for coumaphos will be finalized once the cumulative assessment for all of the organophosphate
pesticides is complete.
The Coumaphos RED of 1996 established that the U.S. Department of Agriculture-Animal and
Plant Health Inspection Service (USDA-APfflS) uses of coumaphos were eligible for reregistration,
primarily due to the important use of this insecticide in the USDA-APfflS Cattle Fever Tick
Eradication Program and the Program's significant benefit to the U.S. economy. In addition, the
USDA-APfflS has an established cholinesterase monitoring program, in which staff are tested
periodically and prevented from handling coumaphos if cholinesterase levels reach a level of concern.
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In the 1996 RED, the Agency deferred making a regulatory decision on all uses of coumaphos other
than USDA-APHIS uses, contingent on the submission and review of coumaphos-specific handler
exposure studies. However, more recently, based on the small volume, declining trend in the use of
coumaphos as livestock and swine bedding treatments, and other information, the Agency determined
that the chemical-specific handler exposure studies previously required in the Data Call-In issued along
with the 1996 RED were no longer needed.
The attached document, in addition to reassessing coumaphos tolerances, follows-up on the 1996
RED by issuing the reregistration eligibility decision for the non-USDA uses of coumaphos. In order to
make this decision, the Agency reviewed and considered surrogate handler exposure data submitted by
the registrant and conducted an occupational risk assessment incorporating surrogate exposure data
available. The Agency has not conducted a new risk assessment for the effects of coumaphos on non-
target species (e.g., fish, birds, mammals), because we have no reason to believe our conclusions
would change since the 1996 RED.
A Notice of Availability for this Reregistration Eligibility Decision Addendum and FQPA
Tolerance Reassessment Progress Report for coumaphos is being published in the 'Tederal Register."
To obtain a copy of this document, please contact the OPP Public Regulatory Docket (7502C), US
EPA, Ariel Rios Building, 1200 Pennsylvania Avenue NW, Washington, DC 20460, telephone (703)
305-5805. Electronic copies of the RED Addendum and all supporting documents are available on the
Internet See "http://www.epa.gov/pesticides/op."
The RED Addendum is based on the updated technical information found in the coumaphos
public docket. The docket not only includes background information and comments on the Agency's
preliminary risk assessment, it also includes the Agency's revised risk assessment for coumaphos
(revised as of January 13,2000), a document summarizing the Agency's Response to Comments, and
recent revisions/addenda to the dietary (food), drinking water and occupational risk assessments. The
Response to Comments document addresses corrections to the preliminary risk assessment submitted
by the chemical registrant, as well as responds to comments submitted by the general public and
stakeholders during the comment period on the risk assessment. The docket also includes comments
on the revised risk assessment, and risk mitigation proposals submitted during Phase 5. A proposal
was submitted for coumaphos by the technical registrant, Bayer Corporation. Comments and
suggestions on risk mitigation were also submitted by Bayer Corporation.
This document and the process used to develop it are the result of a pilot process to facilitate
greater public involvement and participation in the reregistration and/or tolerance reassessment -
decisions for the organophosphate pesticides. As part of the Agency's effort to involve the public in the
implementation of the Food Quality Protection Act of 1996 (FQPA), the Agency is undertaking a
special effort to maintain open public dockets on the organophosphate pesticides and to engage the
public in the reregistration and tolerance reassessment processes for these chemicals. This open
process follows the guidance developed by the Tolerance Reassessment Advisory Committee (TRAC),
a large multi-stakeholder advisory body that advised the Agency on implementing the new provisions of
the FQPA. The reregistration and tolerance reassessment reviews for the organophosphate pesticides
are following this new process.
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Please note that the coumaphos risk assessment and the attached RED Addendum concern
only this particular organophosphate. This document presents the Agency's reregistration
decision, except for the decision on tolerance reassessment. Because the FQPA directs the
Agency to consider available information on the basis of cumulative risk from substances sharing
a common mechanism of toxicity, such as the toxicity expressed by the organophosphates
through a common biochemical interaction with cholinesterase enzyme, the Agency will evaluate
the cumulative risk posed by the entire organophosphate class of chemicals after completing the
risk assessments for the individual organophosphates. The Agency is working towards
completion of a methodology to assess cumulative risk and the individual risk assessments for
each organophosphate are likely to be necessary elements of any cumulative assessment. The
Agency has decided to move forward with individual assessments and to identify mitigation
measures necessary to address the human health risk estimates associated with the current uses of
coumaphos. The Agency will issue the final tolerance reassessment decision for coumaphos
once the cumulative assessment for all of the organophophates is complete.
In this RED Addendum, the Agency has determined that coumaphos will be eligible for
reregistration provided that all the conditions identified in this document are satisfied, including
implementation of the risk mitigation measures outlined in Section IV of the document. The
Agency believes that current uses of coumaphos may pose unreasonable adverse effects to
human health, and that such effects can be mitigated with the risk mitigation measures identified
in this RED. Accordingly, the Agency recommends that registrants implement these risk
mitigation measures immediately. Section IV of this RED describes labeling amendments for
the technical, manufacturing-use and end-use products necessary to implement these mitigation
measures. Instructions for registrants on submitting revised labeling and the time frame
established to do so can be found in Section V of this document.
Should a registrant fail to implement any of the risk mitigation measures outlined in this
document, the Agency will continue to have concerns about the risks posed by coumaphos.
Where the Agency has identified any unreasonable adverse effect to human health, the Agency
may at any time initiate appropriate regulatory action to address this concern. At that tune, any
affected person(s) may challenge the Agency's action.
If you have questions on this document or the proposed label changes, please contact the
Chemical Review Manager, Monica Alvarez, at (703) 308-8026. For questions about product
reregistration, please contact Moanna Appleyard at (703) 308-8175.
a
Lois A. Rossi^ Director
Special Review and
Reregistration Division
Attachment
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Registration Eligibility Decision Addendum and FQPA
Tolerance Reassessment Progress Report
for
Coumaphos
Case No. 0018
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TABLE OF CONTENTS
COUMAPHOS TEAM
GLOSSARY OF TERMS AND ABBREVIATIONS jv
EXECUTIVE SUMMARY j
I. INTRODUCTION 4
H. CHEMICAL OVERVIEW ^
o
A. Regulatory History 6
B. Chemical Identification 6
C. Use Proffle 7
D. Estimated Usage of Pesticide g
HI. SUMMARY OF COUMAPHOS RISK ASSESSMENT 9
A. Human Health Risk Assessment 9
1. Dietary Risk from Food 10
a. Toxicity 10
b. FQPA Safety Factor 10
c. Population Adjusted Dose (PAD) '.'.'.'.'.10
d. Exposure Assumptions j j
e. Food Risk Characterization 11
2. Dietary Risk from Drinking Water 12
a. Surface Water 13
b. Ground Water 13
c. Drinking Water Levels of Comparison (DWLOCs) 13
3. Aggregate Risk 14
4. Occupational Risk 15
a. Toxicity '.'.'.'.'.'.'.'. 15
b. Exposure lg
c. Occupational Handler Risk Summary 18
1) Occupational Handler Risk 19
2) Post-Application Occupational Risk 24
B. Environmental Risk Assessment 24
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IV. RISK MANAGEMENT AND REREGISTRATION DECISION 24
A. Determination of Reregistration Eligibility 24
B. Summaryof PhaseS Comments and Responses 26
C. Regulatory Position 27
1. FQPA Assessment 27
a. "Risk Cup" Determination •'• 27
b. Tolerance Summary 28
2. Endocrine Disrupter Effects 29
D. Regulatory Rationale 29
1. Human Health Risk Mitigation 30
a. Dietary Risk Mitigation 30
1) Acute Dietary (Food) 30
2) Chronic Dietary (Food) 30
3) Drinking Water 30
b. Occupational Risk Mitigation 31
E. Label Modifications 32
F. Other Labeling Modifications 32
1. Endangered Species Statement 32
V. WHAT REGISTRANTS NEED TO DO 33
A. Manufacturing-Use Products 33
1. Additional Generic Data Requirements 33
2. Labeling for Manufacturing-Use Products 34
B. End-Use Products 34
1. Additional Generic Data Requirements 34
2. Labeling for End-Use Products 34
C. Existing Stocks 34
D. Labeling Changes Summary Table 36
VI. RELATED DOCUMENTS AND HOW TO ACCESS THEM 44
VH. APPENDICES 45
A. TABLE OF USE PATTERNS ELIGIBLE FOR REREGISTRATION 47
B. DATA SUPPORTING GUIDELINE REQUIREMENTS FOR THE
REREGISTRATION OF COUMAPHOS 51
C. LIST OF AVAILABLE RELATED DOCUMENTS 57
D. CITATIONS SUPPORTING THE REREGISTRATION ELIGIBILITY
DECISION ADDENDUM AND FQPA TOLERANCE
REASSESSMENT PROGRESS REPORT (BIBLIOGRAPHY) 59
E. LIST OF REGISTRANTS 69
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COUMAPHOS TEAM
Office of Pesticide Programs:
Health Effects Risk Assessment
Christina Jarvis
Sherrie Kinard
Alan Nielsen
Renee Sandvig
Environmental Fate Risk Assessment
Kevin Costello
James Hetrick
Use and Usage Analysis
ArtGrube
Stephen Smearman
Registration Support
Linda DeLuise
Risk Management
Monica Alvarez
Daniel Helfgott
Reregistration Branch n
Reregistration Branch n
Reregistration Branch n
Reregistration Branch n
Environmental Risk Branch I
Environmental Risk Branch I
Economic Analysis Branch
Economic Analysis Branch
Insecticide Branch
Special Review Branch
Special Review Branch
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GLOSSARY OF TERMS AND ABBREVIATIONS
AE
a.i.
AGDCI
ai
aPAD
AR
ARC
ARI
BCF
CAS
CI
CNS
cPAD
CSF
CFR
CSFII
DCI
DEEM
DFR
DRES
DWEL
DWLOC
EC
EEC
EP
EPA
FAO
FDA
FIFRA
FFDCA
FQPA
FOB
G
GENEEC
GLC
Acid Equivalent
Active Ingredient
Agricultural Data Call-In
Active Ingredient
Acute Population Adjusted Dose
Anticipated Residue
Anticipated Residue Contribution
Aggregate Risk Index
Bioconcentration Factor
Chemical Abstracts Service
Cation
Central Nervous System
Chronic Population Adjusted Dose
Confidential Statement of Formula
Code of Federal Regulations
USDA Continuing Surveys for Food Intake by Individuals
Data Call-in
Dietary Exposure Evaluation Model
Dislodgeable Foliar Residue
Dietary Risk Evaluation System
Drinking Water Equivalent Level (DWEL) The DWEL represents a medium specific
(i.e., drinking water) lifetime exposure at which adverse, noncarcinogenic health effects
are not anticipated to occur.
Drinking Water Level of Comparison.
Emulsifiable Concentrate Formulation
Estimated Environmental Concentration. The estimated pesticide concentration in an
environment, such as a terrestrial ecosystem.
End-Use Product
U.S. Environmental Protection Agency
Food and Agriculture Organization
Food and Drug Administration
Federal Insecticide, Fungicide, and Rodenticide Act
Federal Food, Drug, and Cosmetic Act
Food Quality Protection Act
Functional Observation Battery
Granular Formulation
Tier I Surface Water Computer Model
Gas Liquid Chromatography
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GLOSSARY OF TERMS AND ABBREVIATIONS
GLN Guideline Number
GM Geometric Mean
GRAS Generally Recognized as Safe as Designated by FDA
HA Healtii Advisory (HA)- The HA values are used as informal guidance to municipalities
and other organizations when emergency spills or contamination situations occur.
HAFT Highest Average Field Trial
HOT Highest Dose Tested
IR Index Reservoir
L Liter
LCSO Median Lethal Concentration. A statistically derived concentration of a substance that
can be expected to cause death in 50% of test animals. It is usually expressed as the
weight of substance per weight or volume of water, air or feed, e.g., mg/1, mg/kg or
ppm.
LDSO Median Lethal Dose. A statistically derived single dose that can be expected to cause
death in 50% of the test animals when administered by the route indicated (oral, dermal,
inhalation). It is expressed as a weight of substance per unit weight of animal, e.g.,
mg/kg.
LEL Lowest Effect Level
LOG Level of Concern
LOD Limit of Detection
LOAEL Lowest Observed Adverse Effect Level
MATC Maximum Acceptable Toxicant Concentration
MCLG Maximum Contaminant Level Goal (MCLG) The MCLG is used by the Agency to
regulate contaminants in drinking water under the Safe Drinking Water Act.
mg/kg/day Milligram Per Kilogram Per Day
mg/L Milligrams Per Liter
MOE Margin of Exposure
MP Manufecturing-Use Product
MPI Maximum Permissible Intake
MRID Master Record Identification (number). EPA's system of recording and tracking
studies submitted.
N A Not Applicable
N/A Not Applicable
NAWQA USGS National Water Quality Assessment
NOEC No Observable Effect Concentration
NOEL No Observed Effect Level
NOAEL No Observed Adverse Effect Level
NPDES National Pollutant Discharge Elimination System
IV
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GLOSSARY OF TERMS AND ABBREVIATIONS
NR
OP
OPP
OPPTS
Pa
PAD
PADI
PAG
PAM
PCA
PDP
PHED
Pffl
ppb
PPE
ppm
PRN
PRZM/
EXAMS
Qi*
RAC
RBC
RED
REI
RfD
RQ
RS
RUP
SAP
SCI-GROW
SF
SLC
SLN
TC
TD
TEP
Not Required
Organophosphate
EPA Office of Pesticide Programs
EPA Office of Prevention, Pesticides and Toxic Substances
pascal, the pressure exerted by a force of one newton acting on an area of one square
meter.
Population Adjusted Dose
Provisional Acceptable Daily Intake
Pesticide Assessment Guideline
Pesticide Analytical Method
Percent Crop Area
USDA Pesticide Data Program
Pesticide Handler's Exposure Data
Preharvest Interval
Parts Per Billion
Personal Protective Equipment
Parts Per Million
Pesticide Registration Notice
Tier n Surface Water Computer Model
The Carcinogenic Potential of a Compound, Quantified by the EPA's Cancer Risk
Model
Raw Agriculture Commodity
Red Blood Cell
Reregistration Eligibility Decision
Restricted Entry Interval
Reference Dose
Risk Quotient
Registration Standard
Restricted Use Pesticide
Science Advisory Panel
Tier I Ground Water Computer Model
Safety Factor
Single Layer Clothing
Special Local Need (Registrations Under Section 24(c) of FIFRA)
Toxic Concentration. The concentration at which a substance produces a toxic effect.
Toxic Dose. The dose at which a substance produces a toxic effect.
Typical End-Use Product
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GLOSSARY OF TERMS AND ABBREVIATIONS
TGAI Technical Grade Active Ingredient
TLC Thin Layer Chromatography
TMRC Theoretical Maximum Residue Contribution
torr A unit of pressure needed to support a column of mercury 1 mm high under standard
conditions.
TRR Total Radioactive Residue
Uf? Uncertainty Factor
//g/g Micrograms Per Gram
-jwg/L Micrograms Per Liter
USDA United States Department of Agriculture
USGS United States Geological Survey
UV Ultraviolet
WHO World Health Organization
WP Wettable Powder
WPS Worker Protection Standard
VI
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EXECUTIVE SUMMARY
Coumaphos is an organophosphate insecticide/acaricide used on livestock and swine bedding,
first registered in 1958 for the control of flies, mites, and ticks. Most recently, the Agency granted
emergency FEFRA exemptions to several States for the use of coumaphos in honey bee hives to control
varroa mites and small hive beetles. The Agency also established time-limited tolerances for
coumaphos residues in honey and beeswax associated with these emergency exemptions. Coumaphos
is a small volume use active ingredient, and its use has declined by nearly 50% since 1990.
In the Coumaphos Reregistration Eligibility Decision (RED) document of August 1,1996, the
Agency determined that only U.S. Department of Agriculture-Animal and Plant Health Inspection
Service (USDA-APHIS) uses of coumaphos were eligible for reregistration, primarily due to the
important use of this insecticide in the USDA-APHIS Cattle Fever Tick Eradication Program and the
Program's significant benefit to the U.S. economy. In addition, the USDA-APHIS has an established
cholinesterase monitoring program, in which staff are tested periodically and prevented from handling
coumaphos if cholinesterase levels reach a level of concern. In 1996, prior to the passage of the Food
Quality Protection Act of 1996 (FQPA), the Agency deferred a regulatory decision on all uses of
coumaphos other than the USDA-APHIS dip vat use, contingent on the submission and review of
coumaphos-specific handler exposure studies. Non-USDA uses are spray and back rubber/oiler uses
of the liquid formulations and shaker can, mechanical duster and dust bag uses of the dust formulations.
This document follows up on the Coumaphos RED issued in 1996. It establishes the Agency's
reregistration eligibility and risk management decision for coumaphos uses other than USDA-APHIS
uses, for which no reregistration eligibility decision was made in flie 1996 Coumaphos RED and
provides information on the reassessment of coumaphos tolerances in accordance with the Federal
Food, Drug, and Cosmetic Act (FFDCA) as amended by FQPA. This Act requires EPA to re-
evaluate existing tolerances to ensure that children and other sensitive populations are protected from
pesticide risk, progress of the FQPA tolerance reassessment for coumaphos.
In order to make the reregistration eligibility decision, the Agency reviewed and considered
surrogate handler exposure data submitted by the registrant and conducted an occupational risk
assessment incorporating surrogate exposure data available. The Agency has not conducted a new risk
assessment for the effects of coumaphos on non-target species (e.g., fish, birds, mammals), because we
have no reason to believe our conclusions would change since that time. Because EPA issued the
Coumaphos RED in 1996, before the passage of FQPA; for simplicity, we will refer to this document
as a RED Addendum.
EPA has completed its review of public comments on the revised coumaphos dietary and
occupational risk assessments and is issuing its risk management decisions for this chemical. The
decisions outlined in this document do not include the final tolerance reassessment decision for
coumaphos; however, some tolerance actions will be undertaken prior to the completion of the final
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tolerance reassessment. Six tolerances should be proposed for revocation because the technical
registrant, Bayer Corporation, no longer supports the use of coumaphos on sheep and goats and has
requested voluntary cancellation of these uses. The final tolerance reassessment decision for this
chemical will be issued once the cumulative assessment for all of the organophosphates is complete.
The Agency may need to pursue farther risk management measures for coumaphos once the cumulative
assessment is finalized.
The revised risk assessments are based on review of the required target data base supporting
the use patterns of currently registered products and new information received. The Agency invited
stakeholders to provide proposals, ideas or suggestions on appropriate mitigation measures before the
Agency issued its risk mitigation decision on coumaphos. After considering revised risks, risk
mitigation measures proposed by Bayer Corporation, and comments from other interested parties,
including USDA-APHIS, EPA developed its risk management decision for uses of coumaphos that
pose risks of concern. This decision is discussed fully in this document.
Overall Risk Summary
EPA's human health risk assessment for coumaphos indicates some risk concerns. Food risks,
both acute and chronic, do not exceed the Agency's level of concern. Similarly, acute and chronic
exposures to coumaphos in drinking water, based on surface and groundwater screening modeling, are
not of concern. There are, however, risk concerns for workers who mix, load, and apply coumaphos
to livestock and swine bedding.
To mitigate risks of concern posed by the uses of coumaphos, EPA considered the mitigation
proposal submitted by the technical registrant, as well as comments from other interested parties, and
has decided on a number of label amendments to address worker risk concerns. Results of the risk
• assessments and necessary label amendments to mitigate those risks are presented in this document.
Dietary Risk
Acute and chronic dietary risk assessments for food and drinking water indicate risks do not
exceed the Agency's level of concern; therefore, no mitigation is warranted at this time for any acute or
chronic dietary exposure to coumaphos.
Occupational Risk
Occupational exposure to coumaphos is of concern, and the Agency identified a number of
mitigation measures that need to be implemented at this time. Several applicator risk scenarios
currently exceed the Agency's level of concern [i.e., Margins of Exposure (MOEs) are less than 100 or
Aggregate Risk Indexes (ARIs) are less than 1] at baseline. EPA believes these risks can be mitigated
to an acceptable level with the following label changes: restriction of one formulation to only USDA-
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APHIS use, deletion of a method of application, limitation on the number of animals and area of animal
bedding to be treated, and addition of personal protective equipment. Therefore, with the addition of
the label restrictions and amendments detailed in this document, the Agency has determined that, until
the outcome of the cumulative risk assessment for all of the organophosphates has been decided, all
currently registered uses of coumaphos may continue, except for the uses on sheep and goats for which
the technical registrant has requested voluntary cancellation. In addition, the Agency has determined
that the non-USDA uses of coumaphos, for which no reregistration decision was made in the 1996
RED document, are eligible for reregistration when the label changes outlined in Section IV of this
document are implemented by the registrant.
The Agency is issuing this RED Addendum for coumaphos, as announced in a Notice of
Availability published in the "Federal Register." This document includes guidance and time fiames for
complying with any necessary label changes for products containing coumaphos. As part of the
process discussed by the TRAC, which sought to open up the process to interested parties, the
Agency's risk assessments for coumaphos have already been subject to numerous public comment
periods, and a further comment period for coumaphos was deemed unnecessary. Therefore, there is
no comment period for this document With regard to complying with the risk reduction measures
outlined in this document, the Agency has shortened this time period so that the risks identified herein
are mitigated as quickly as possible. Neither the tolerance reassessment nor the reregistration eligibility
decision for coumaphos can be considered final, however, until the cumulative risk assessment for all
organophosphate pesticides is complete. The cumulative assessment may result in further risk mitigation
measures for coumaphos.
-------
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I.
INTRODUCTION
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was amended in 1988 to
accelerate the reregistration of products with active ingredients registered prior to November 1,1984.
The amended Act calls for the development and submission of data to support the reregistration of an
active ingredient, as well as a review of all submitted data by the U.S. Environmental Protection Agency
(referred to as EPA or "the Agency"). Reregistration involves a thorough review of the scientific
database underlying a pesticide's registration. The purpose of the Agency's review is to reassess the
potential hazards arising from the currently registered uses of the pesticide; to determine the need for
additional data on health and environmental effects; and to determine whether the pesticide meets the
"no unreasonable adverse effects" criteria of FIFRA.
On August 3, 1996, the Food Quality Protection Act of 1996 (FQPA) was signed into law.
This Act amends FIFRA to require tolerance reassessment of all existing tolerances. The Agency had
decided that, for those chemicals that have tolerances and are undergoing reregistration, the tolerance
reassessment will be initiated through this reregistration process. It also requires that by 2006, EPA
must review all tolerances in effect on the day before the date of the enactment of the FQPA, which
was August 3,1996. FQPA also amends the FFDCA to require a safety finding in tolerance
reassessment based on factors including an assessment of cumulative effects of chemicals with a
common mechanism of toxicity. Coumaphos belongs to a group of pesticides called organophosphates,
which share a common mechanism of toxicity - they all affect the nervous system by inhibiting
cholinesterase. Although FQPA significantly affects the Agency's reregistration process, it does not
amend any of the existing reregistration deadlines. Therefore, the Agency is continuing its reregistration
program while it resolves the remaining issues associated with the implementation of FQPA.
The implementation of FQPA has required the Agency to revisit some of its existing policies
relating to the determination and regulation of dietary risk, and has also raised a number of new issues
for which policies need to be created. These issues were refined and developed through collaboration
between the Agency and the Tolerance Reassessment Advisory Committee (TRAC), which was
composed of representatives from industry, environmental groups, and other interested parties. The
TRAC identified the following science policy issues it believed were key to the implementation of
FQPA and tolerance reassessment:
• Applying the FQPA 10-Fold Safety Factor
• Whether and How to Use "Monte Carlo" Analyses in Dietary Exposure Assessments
• How to Interpret "No Detectable Residues" in Dietary Exposure Assessments
• Refining Dietary (Food) Exposure Estimates
• Refining Dietary (Drinking Water) Exposure Estimates
• Assessing Residential Exposure
• Aggregating Exposure from all Non-Occupational Sources
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• How to Conduct a Cumulative Risk Assessment for Organophosphate or Other Pesticides with
a Common Mechanism of Toxicity
• Selection of Appropriate Toxicity Endpoints for Risk Assessments of Organophosphates
• Whether and How to Use Data Derived from Human Studies
The process developed by the TRAC calls for EPA to provide one or more documents for
public comment on each of the policy issues described above. Each of these issues is evolving and in a
different stage of refinement. Some issue papers have already been published for comment in the
Federal Register and others will be published shortly.
In addition to the policy issues that resulted from the TRAC process, the Agency issued on
September 29,2000, a Pesticide Registration Notice (PR 2000-9) that presents EPA's approach for
managing risks from organophosphate pesticides to occupational users. The Worker PR Notice
describes the Agency's baseline approach to managing risks to handlers and workers who may be
exposed to organophosphate pesticides, and the Agency expects other types of chemicals will be
handled similarly. Generally, basic protective measures such as closed mixing and loading systems,
enclosed cab equipment, or protective clothing, as well as increased reentry intervals will be required
for most uses where current risk assessments indicate a risk and such protective measures are feasible.
The policy also states that the Agency will assess each pesticide individually, and based upon the risk
assessment^ determine the need for specific measures tailored to the potential risks of the chemical.
The measures included in this document are consistent with the Worker Pesticide Registration Notice.
This document consists of six sections. Section I contains the regulatory framework for
reregistration/tolerance reassessment as well as descriptions of the process developed by TRAC for
public comment on science policy issues for the organophosphate pesticides and the worker risk
management PR notice. Section n provides a profile of the use and usage of the chemical. Section in
gives an overview of the revised human health risk assessment resulting from public comments and
other information. Section IV presents the Agency's reregjstration eligibility and risk management
decision. Section V summarizes labeling changes necessary based on the risk mitigation measures
outlined in Section IV. Section VI provides information on how to access related documents. Finally,
the Appendices list the use patterns, data supporting guideline requirements and technical supporting
documents, and provide the bibliography, among other information. The revised risk assessments and
related addenda are not included in this document, but are available on the Agency's web page
"http://www.epa.gov/pesticides/op," and in the Public Docket
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H. CHEMICAL OVERVIEW
A. Regulatory History
Coumaphos technical was first registered in the United States in 1958 for use as an insecticide.
The first end-use product, a dust formulation, was registered the following year for the control of insects
on cattle. Coumaphos is currently registered for the control of insects, mites, and ticks on livestock and
swine bedding. Since 1999, the Agency has exempted several State agencies from the provisions of
FIFRA due to emergency conditions that required the use of coumaphos in bee hives to control varroa
mites and small hive beetles. The Agency also established time-limited tolerances for combined
residues of coumaphos and its oxygen analog, coumaphoxon, in honey and beeswax associated with
these emergency exemptions.
The Coumaphos RED, along with a DCI requiring coumaphos-specific worker exposure and
environmental fate studies, was issued in August 1996, prior to the passage of FQPA. In the 1996
RED, the Agency declared the USDA-APfflS dip vat use of coumaphos eligible for reregistration and
deferred making a regulatory determination on the non-USD A uses, pending submission of the worker
exposure data. This RED Addendum reflects a reassessment of all data submitted in response to the
1996 DCI and other available data, provides an update on FQPA tolerance reassessment progress and
announces the reregistration eligibility and risk management decision for the non-USDA uses of
coumaphos.
B. Chemical Identification
Coumaphos:
H5C20
OC2H5
• Common Name:
• Chemical Name:
• Chemical family:
• Case number:
Coumaphos
0,0-diethylO-(3-chloro-4-methyl-2-oxo-2H-l-
benzopyran-7-yl) phosphorothioate
Organophosphate
0018
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CAS registry number:
OPP chemical code:
Empirical formula:
Molecular weight:
Vapor Pressure:
Trade and other names:
Basic manufacturer:
56-72-4
036501
C14H16C105PS
362.8
lxlO-7mmHg
Asuntol, Bay 21/199, Baymix, Co-Ral, ENT-17957,
Muscatox, Resitox
Bayer Corporation (technical registrant)
Technical coumaphos is a tan solid with a purity of 96% and a melting point of 90-95°C. At
20°C, coumaphos is soluble in acetone (23.82 g/100 ml) and diethyl phthalate (21.50 g/100 ml); much
less soluble in denatured alcohol and xylene (0.9 g/100 ml in each); only slightly soluble in octanol (0.13
g/100 ml), hexane (0.07 g/100 ml), and mineral spirits (0.09g/100 ml); and insoluble in water (0.002
g/100 ml). Coumaphos is stable under normal conditions, but hydrolyzes slowly under alkaline
conditions.
C. Use Profile
The following information is based on the currently registered uses of coumaphos:
Type of Pesticide: Insecticide/Acaricide
Summary of Use Sites:
All registered uses are classified as indoor food uses.
Food: Coumaphos is used as a direct animal treatment on beef and dairy cattle, horses,
goats, sheep and swine. Predominant use is on beef cattle.
Residential: None
Public Health: None
Other Nonfood: Swine bedding
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Target Pests: Flies (face fly, horn fly), ticks, lice, mites (scabies mite) and screw
worms.
Formulation Types Registered: Technical Grade Active Ingredient (96% pure),
manufacturing product (25% ai dust), end-use products (1% ai dust, 11.6% ai and
6.15% ai emulsifiable concentrates, and 42% ai flowable concentrate).
Method and Rates of Application:
Equipment - Dip vats, low and high-pressure hand wands, back rubber/oiler,
mechanical dusters, dust bags and shaker cans.
Method and Rate - Applied directly to livestock. Depending on animals treated and
formulation type, the maximum label application rates range from 0.005 to 0.025 Ibs
ai/gallon for spray or dip, 0.076 Ibs ai/gallon of oil for back rubbers, 0.000625 to
0.013 Ibs ai/animal for dust, and 0.042 Ibs ai/1,000 sq. ft. of swine bedding.
Timing - Used primarily during early spring to late summer or during the fly season.
Multiple applications to livestock and livestock areas are allowed.
Use Classification: Two liquid products, the 11.6% emulsifiable concentrate and the
42% flowable are classified as Restricted Use Pesticides (RUPs); all other products
have general classification.
D. Estimated Usage of Pesticide
This section summarizes the best estimates available for many of the pesticide uses of
coumaphos, based on pesticide usage information for 1990-1999 available to the Agency. A full listing
of all uses of coumaphos, with the corresponding use and usage data for each site (cattle or other
livestock), has been completed and is included in the "Quantitative Usage Analysis for Coumaphos,"
dated August 15,2000, which is available in the Public Docket. The data, reported on an aggregate
and site basis, reflect annual fluctuations in use patterns as well as the variability in using data from
various information sources. Approximately 71,000 Ibs a.i. of coumaphos is used annually in the
United States, according to Agency estimates.
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Table 1. Coumaphos Estimated Usage for Representative Sites
Site
Cattle
Other Livestock
Lbs. Active Ingredient Applied (Likely Average1)
59,000
12,000
Percent Livestock Treated (Likely Average) ' ""' ,
5.1%
1.3%
1 Likely averages are the EPA's estimates of what the average uses are likely to be.
Sources: U.S. Census of Agriculture; State Usage Surveys from TX, KS, NY, WY, and NV; State use recommendations; USDA,
NASS, 2000 and EPA data. Refer to the "Quantitative Usage Analysis for Coumaphos," dated August 15, 2000, prepared by
OPP Biological and Economic Analysis Division.
SUMMARY OF COUMAPHOS RISK ASSESSMENT
The following is a summary of EPA's revised human health risk findings and conclusions for the
organophosphate pesticide coumaphos, as fully presented in the document, "Revised Dietary and
Occupational Risk Assessment Update for the Coumaphos RED Published August, 1996," dated
January 13, 2000 and more recent revisions to the dietary (food), drinking water and occupational risk
assessments. The purpose of this summary is to assist the reader by identifying the key features and
findings of this risk assessment, and to better understand the conclusions reached in the assessment.
The risk assessments presented here form the basis of the Agency's risk management decision
for coumaphos only; the Agency must complete a cumulative assessment of the risks of all the
organophosphate pesticides before any final decisions can be made.
A. Human Health Risk Assessment
EPA issued its preliminary risk assessments for coumaphos on September 2, 1999 (Phase 3 of
the TRAC process). In response to public comments and a dietary risk assessment submitted by the
technical registrant during Phase 3, the risk assessments were updated and refined. Major revisions to
the human health risk assessment are listed below:
• Development of refined Tier 3 acute and chronic dietary risk assessments;
• Incorporation of refined percent livestock treated information for beef cattle, dairy
cattle and swine commodities and monitoring data for the U.S. Department of
Agriculture (USDA) Pesticide Data Program (PDP) for milk;
Deletion of spray foam (canceled effective July 29, 1999) and wettable powder
formulations (canceled effective January 31, 2000) from the occupational exposure and
risk assessment.
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In addition to the changes made during Phase 4, the Agency recently revised the dietary (food)
risk assessment to correct an error in the residue files and revised the drinking water assessment to
include less conservative K^. and water solubility assumptions for the oxygen analog, coumaphoxon.
The Agency also developed an addendum to the revised occupational risk assessment, which provides
occupational risk estimates for different handler exposure scenarios considering current labeled
personal protective equipment. These documents are available in the OPP Public Docket for
coumaphos.
1. Dietary Risk from Food
a. Toxicity
The Agency has reviewed all toxiciry studies submitted and has determined that the toxicity
database is essentially complete, and that it supports a reregistration eligibility determination for all
currently registered uses. Further details on the toxicity of coumaphos can be found in the January 13,
2000 human health risk assessment A brief overview of the studies used for the dietary risk
assessment is outlined in Table 2 in this document.
b. FQPA Safety Factor
The FQPA Safety Factor was reduced to IX. The toxiciry database includes an acceptable
two-generation reproduction study in rats, acceptable prenatal developmental toxicity studies in rats
and rabbits, and acceptable acute and subchronic neurotoxiciry studies in rats. These studies show no
increased sensitivity to fetuses as compared to maternal animals following acute in utero exposure in
the developmental rat and rabbit studies and no increased sensitivity to pups as compared to adults in a
multi-generation reproduction study in rats. There was no evidence of abnormalities in the development
of the fetal nervous system in the pre/postnatal studies. Adequate actual data, surrogate data, and/or
modeling outputs are available to satisfactorily assess dietary exposure and to provide a screening level
drinking water exposure assessment. The assumptions and models used in the assessments do not
underestimate the potential risk for infants and children. Therefore, the 10X factor required by FQPA
was reduced to IX.
c.
Population Adjusted Dose (PAD)
The PAD is a term that characterizes the dietary risk of a chemical, and reflects the Reference
Dose, either acute or chronic, that has been adjusted to account for the FQPA safety factor (i.e.,
RfD/FQPA safety factor). In the case of coumaphos, the FQPA safety factor is 1; therefore, the acute
or chronic RfD is the same as the acute or chronic PAD, respectively. A risk estimate that is less than
100% of the acute or chronic PAD does not exceed the Agency's risk concern.
10
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Table 2. Summary of Toxicological Endpoints and Other Factors Used in the Human Dietary
Risk Assessment of Coumaphos
Assessment
Acute Dietary
Chronic Dietary
Dose
2.0 mg/kg/day
(LOAEL)
0.025 mg/kg/day
(NOAEL)
Endpoint-
,
Plasma ChE
inhibition in
females and RBC
ChE inhibition in
both male and
female rats
Plasma and RBC
ChE inhibition in
both male and
female dogs seen
at the LOAEL of
0.77 mg/kg/day
xStudy , >
" ' j-
Acute Oral
Neurotoxicity in
Rats(MRID
44544801)
Chronic Toxicity in
Dog(MRK>
43055301)
OF;;
-
300*
100
fQPA,' '
Safety"*- ,
Factor ^ ,
IX
IX
PAD
, ,
0.007
mg/kg/day
0.0003
mg/kg/day
uncertainty ractor is JUU due to an additional 3X tor the lack of a NOAEL.
d. Exposure Assumptions
Revised acute and chronic dietary risk analyses for coumaphos were conducted with the
Dietary Exposure Evaluation Model (DEEM™). DEEM incorporates consumption data generated in
USDA's Continuing Surveys of Food Intakes by Individuals (CSFII), 1989-92. The dietary exposure
assessments presented in the "Revised Acute and Chronic Dietary Exposure and Risk Analyses for
Coumaphos" and in the "Revised Dietary and Occupational Risk Assessment Update for the
Coumaphos RED Published August, 1996" (both dated January 13,2000) have been revised using the
correct residue values for pork commodities. For more details on this revision, please refer to the
memorandum entitled: "Addendum to the Acute Dietary Exposure Analysis for Coumaphos."
The Tier 3 acute dietary analysis used monitoring data for milk and percent livestock treated for
beef, milk, and pork commodities.
e.
Food Risk Characterization
Generally, a dietary risk estimate that is less than 100% of the acute or chronic Population
Adjusted Dose does not exceed the Agency's risk concerns. The coumaphos acute dietary risk from
food is well below the Agency's level of concern; that is, less than 100% of the acute PAD is utilized.
For example, for the most exposed subgroups, infants (<1 year) and children (1-6 years), the percent
acute PAD values are 21% and 15%, respectively, at the 99.9th percentile of exposure.
11
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The chronic dietary risk from food alone is well below the Agency's level of concern. For the
most exposed subgroups, children (1-6 years) and children (7-12 years) the percent chronic PAD
values are 13% and 9%, respectively.
The revised Tier 3 acute and chronic dietary analyses are highly refined. Additional refinements
can be made using processing data from cooking and processing studies. These refinements will be
considered when the cumulative assessment for all of the organophosphates is conducted.
2. Dietary Risk from Drinking Water
Drinking water exposure to pesticides can occur through ground water and surface water
contamination. EPA considers both acute (one day) and chronic (lifetime) drinking water risks and
uses either modeling or actual monitoring data, if available, to estimate those risks. Modeling is
considered to be an unrefined assessment and provides a high-end estimate of risk In the case of
coumaphos, no monitoring data for either ground or surface water were available; therefore, modeling
was used to estimate drinking water risks from these sources.
The GENEEC and SCI-GROW screening models were used to estimate surface water and
groundwater concentrations of coumaphos and its oxygen analog, coumaphoxon. This degradate is
considered in the drinking water assessment, because it is part of the tolerance expression.
The environmental fate database for coumaphos indicates that it is persistent (tJ/2 >1 year) and
relatively immobile (Kd=61 to 298 ml/g; 1^=3,994 to 11,422) in soil. Since the Agency does not
have environmental fate data for coumaphoxon, it originally used the most conservative assumptions .for
its persistence (t1/2 >1 year) and mobility (K^O.l) for drinking water assessment'purposes. However,
on June 6,2000, the Agency revised the drinking water assessment for coumaphos using a computer
estimation program (EPI version 3.04), and estimated less conservative K^ value (92.3) and water
solubility value (31.61 at 25°C) for coumaphoxon. Therefore, the estimated environmental
concentrations for total coumaphos (coumaphos and coumaphoxon) presented below reflect the
revised concentrations. Please refer to the document: "Revised Tier 1 Drinking Water Assessment for
Coumaphos," dated June 6,2000 for more details.
For other model input parameters used in the drinking water assessment, the Agency used the
guidance it generated on proposed USDA land farming methods. The recommended application rate
for coumaphos spent solution from dip vat operations on non-agricultural land is 10,000 liters (L) of
coumaphos spent solution containing 10 ppb spread over a one-acre field. A conversion efficiency of
coumaphos to coumaphoxon of 10.2% was derived from available (supplemental) data on
photodegradation in water. This conversion efficiency was used to estimate a coumaphoxon
application rate of 0.02 Ibs ai/A.
12
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The Agency believes the revised environmental concentrations (EECs) are still conservative
estimates because most of the coumaphos spent solution resulting from the dip use on livestock is
collected and transported to concrete-lined evaporation pits, thereby negating any potential for
groundwater contamination.
a.
Surface Water
Tier IGENEEC screening model, representing a worst-case runoff scenario for pesticides in
surface water, was used to estimate the upper-bound concentrations in surface water. Total
coumaphos (coumaphos + coumaphoxon) acute and chronic estimated environmental concentrations in
drinking water derived from surface water sources are not likely to exceed 1.86 ppb and 0.41 ppb,
respectively.
b. Ground Water
A Tier I screening model, SCI-GROW, was used to estimate total coumaphos concentrations
in ground water. This is an empirical model based on field data from prospective ground water studies.
Estimated environmental concentration of total coumaphos, representing acute and chronic exposures
to ground water, is 0.17 ppb.
c. Drinking Water Levels of Comparison (DWLOCs)
To determine the maximum allowable contribution of water-containing pesticide residues
permitted in the diet, EPA first looks at how much of the overall allowable risk is contributed by food
(and if appropriate, residential uses) and then determines a "drinking water level of
comparison"(DWLOC) to determine whether modeled or monitoring levels exceed this level. The
Agency uses the DWLOC as a surrogate to capture risk associated with exposure from pesticides in
drinking water. The DWLOC is the maximum concentration in drinking water which, when considered
together with dietary exposure, does not exceed a level of concern.
The results of the Agency's drinking water analysis are summarized herein. Details of this
analysis, which used screening models, are found in the "Revised Dietary and Occupational Risk
Assessment Update for the Coumaphos RED Published August, 1996," dated January 13, 2000. As
mentioned above, the June 16,1999 drinking water assessment for coumaphos was revised on June 6,
2000. The revised coumaphos EECs are presented below in Tables 3 and 4. The reader is referred to
the "Revised Tier 1 Drinking Water Assessment for Coumaphos," dated June 6,2000, for more
details.
For acute risk, potential exposure to drinking water derived from either ground or surface
water is not of concern for any population sub-group. The table below presents the calculations from
the acute drinking water assessment.
13
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Table3. Summary of DWLOC Calculations for Acute Risk
Population %
Subgroup
' • '„ ' '
US.
Population
Females
(13-50 years)
Infants (<1
year)
Acute PAD '
' ""^~~ T,
0.007
0.007
0.007
Food Exposure
(rag&g/day) f,._
\ ^ *
y/ ^ / y s
0.000525
0.000247
0.001492
Allowable
^Water Exposure
' -,«~
0.006475
0.006669
0.005508
Ground -"
Water EEC,
GROW); "
0.17
0.17
0.17
Surface Water *•
EEC/ppb^ --
< r-' *'
1.9
1.9
1.9
DWLOS ',
^PpD/ ^
" i
111
200
55
For chronic risk, potential exposure to drinking water derived from ground water is not of
concern. Average (chronic) EECs in ground water do not exceed OPP's levels of comparison or
DWLOCs for any population sub-group.
Table 4. Summary of DWLOC Calculations for Chronic Risk
Population
Subgroup
'V~ '"/
' /s
US.
Population
Children (1-6
years)
Females (13-
50 years)
Chronic PAD "'"
(mg/kg/day) -
"•*•*
^
10
2.7
8.7
a The GENEEC model estimated 56-day (average) concentration is divided by a factor of 3 prior to comparison with the
DWLOCchronic. In this case, (1.2ppb)/3 = 0.41 ppb.
3. Aggregate Risk
An aggregate risk assessment looks at the combined risk from dietary exposure (food and
drinking water routes) and residential exposure to homeowners who handle pesticides or children who
incidentally become exposed to these chemicals (e.g., hand-to-mouth exposure, turfgrass ingestion) in
residential areas. Since coumaphos has no residential uses, acute and chronic aggregate risks include
exposures from food and drinking water only. Acute exposure refers to the exposure for one day and
chronic refers to that of a lifetime. Generally, all risks from these exposures must have MOEs of
greater than 100 to be not of concern to the Agency. Results of the aggregate risk assessment are
summarized herein, and are discussed extensively in the "Revised Dietary and Occupational Risk
Assessment Update for the Coumaphos RED Published August, 1996," dated January 13, 2000.
14
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Acute and chronic aggregate risks are not of concern for the Agency. When residues of
coumaphos in drinking water are considered with exposures from food uses, the resulting acute and
chronic aggregate human health risks are within acceptable levels.
4. Occupational Risk
Occupational workers can be exposed to a pesticide through mixing, loading, and/or applying a
pesticide, or re-entering treated sites. Residents or homeowners can be exposed to a pesticide through
mixing, loading, or applying a pesticide, or through entering or performing other activities on treated
areas. Since the only registered uses of coumaphos are on livestock and swine bedding, occupational
handlers of coumaphos are limited to individual farmers and USDA-APHIS workers who mix, load,
and/or apply the pesticide. Risk for all of these potentially exposed populations is measured by a
Margin of Exposure (MOE), which determines how close the occupational or residential exposure
comes to a No Observed Adverse Effect Level (NOAEL). Generally, MOEs greater than 100 do not
exceed the Agency's risk concern. In the case of coumaphos, the inhalation target MOE is 300, due to
the uncertainty associated with the use of a LOAEL, and the dermal target MOE is 100.
a. Toxicity
The toxicity of coumaphos is integral to assessing the occupational risk. All risk calculations are
based on the most current toxicity information available for coumaphos, including 21-day dermal and
5-day dermal toxicity studies. The toxicological endpoints, and other factors used in the occupational
risk assessment for coumaphos are listed below.
Table 5a. Summary of Toxicological Endpoints and Other Factors Used in the Human
Occupational Risk Assessment for Coumaphos
Assessment
Short-term dermal
Intermediate- term
dermal
Short-term
inhalation
Intermediate -term
inhalation
Dose
NOAEL = 5.0
mg/kg/day
NOAEL = 0.5
mg/kg/day
LOAEL=2.0
mg/kg/day
LOAEL=0.2
mg'kg/day
Endpoint
Brain ChE inhibition
in female rats
RBC ChE inhibition
in rats
Plasma ChE
inhibition in female
rats and RBC ChE
inhibition in male and
female rats
RBC ChE inhibition
in rats
Study " '' J ,r
,<•" s
11 c \ ?
5-day dermal toxicity study in
rats (MRID 44749401)
21-day dermal toxicity study
in rats (42084901)
Acute oral neurotoxicity study
in rats (MRID 44544801)
1 3-week dietary study in rats
(MRID 00126527)
y" '
,Absotptioa
"iactor -**;
N/A
N/A
100 percent
absorption
assumed
100 percent
absorption
assumed
15
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Coumaphos technical is highly acutely toxic via the oral (toxicity category I) and inhalation
routes of exposure (toxicity category E). It is moderately toxic via the dermal route of exposure
(toxicity category HI) and is not a dermal sensitizer or irritant. Coumaphos is classified as a Group E
chemical, indicating that it is "Not Likely" to be carcinogenic in humans via relevant routes of exposure.
Table 5b. Acute Toxicity Profile for Occupational Exposure for Coumaphos
Route of Exposure
Oral
Dermal
Inhalation
Eye Irritation
Dermal Irritation
Dermal Sensitizer
Category Basis * *
LD50 > 240 mg/kg - male rat; LD50 = 17 mg/kg - female rat
(MRID 001 10597)
LD50> 2400 mg/kg - male and female rats (MRID 001 10598)
1 hour inhalation LC50= 1.081 mg/L -male rat; 1 hour inhalation LCJO
= 0.341 mg/L female rat (MRID 001 10601)
Mild irritant, resolved by day 7 (MRID 001 10599)
Not irritating (MRID 001 10600)
Not a sensitizer (MRID 001 10602)
Tpxicity fcategory
I
in
ii
in
IV
N/A
b. Exposure
Coumaphos-specific handler exposure data were not available, so risks to pesticide handlers
were assessed using data from the Pesticide Handlers Exposure Database (PHED) for most of the
identified occupational exposure scenarios. Since PHED does not contain data to assess exposures
resulting from loading and applying dust formulations, for informational purposes, the Agency used the
published study: "Application Exposure to the Home Gardener" (1985) to estimate dermal exposure
associated with dust application to livestock. However, the Agency believes the exposures derived
from this study are an under estimate. This is because the exposures from applying a dust formulation
to low garden vegetables will be very different from applying to livestock which are taller, mobile, and
more active.
The Occupational and Residential Exposure Task Force (ORETF) study submitted by Hie
technical registrant presents inhalation and dermal exposures estimates from applying dusts to garden
vegetables and could not be used to assess exposure to handlers likely to occur from the use of
coumaphos on livestock. Our concerns for the dermal exposure estimates derived from this study
were the same as our concerns were for the 1985 data. For the inhalation exposure, EPA believes the
exposures from applying dusts to relatively tall, moving livestock are likely to be significantly higher than
those resulting from the application of dusts to low-growing plants since it is likely that more dust will
reach the applicator's breathing zone during application to livestock. Therefore, the Agency had no
data to estimate inhalation exposure from loading and/or applying dust formulations.
Standard assumptions including average body weight, work day, daily animals or area treated,
and volume of pesticide were used to calculate risk estimates. The quality of the data and exposure
16
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factors represent the best sources of data currently available to the Agency for completing these kinds
of assessments. These exposure factors are all standard values that have been used by the Agency
over several years, and the PHED unit exposure values are the best available estimates of exposure.
Some PHED unit exposure values are high quality while others represent low quality, but are the best
available data. The quality of the data used for each scenario assessed is discussed in the revised
"Occupational Exposure and Risk Assessment Updating the Coumaphos RED Published August,
1996," dated December 28,1999, which is available in the public docket.
Anticipated use patterns and application methods, range of application rates, and daily amount
treated were derived from current labeling. Application rates specified oncoumaphos labels range
from 0.005 to 0.025 pounds of active ingredient per gallon for sprays and dips, 0.076 Ibs ai/gallon of
oil for back rubbers, 0.000625 to 0.013 Ibs ai/animal for dust, and 0.042 Ibs ai/1,000 sq. ft. of swine
bedding. The Agency typically uses number of animals or area treated per day that are thought to
represent 8 solid hours of application work for specific types of application equipment
Occupational handler exposure assessments are conducted by the Agency using different levels
of personal protection. The Agency typically evaluates all exposures with minimal protection and then
adds additional protective measures using a tiered approach to obtain an appropriate MOE (i.e., going
from minimal to maximum levels of protection). The lowest tier is represented by the baseline exposure
scenario, followed by, if required (i.e., MOEs are less than 100), increasing levels of risk mitigation,
such as personal protective equipment (PPE) and engineering controls (EC). Some of the current
labels of coumaphos products require handlers to wear long pants, long-sleeved shirt, and chemical-
resistant gloves. The levels of protection that formed the basis for calculations of exposure from
coumaphos activities include:
Baseline:
Label:
Additional PPE:
Engineering controls:
Long-sleeved shirt and long pants, shoes and socks.
Long-sleeved shirt and long pants, chemical-resistant footwear plus
socks and chemical-resistant gloves. (Note: labels of coumaphos liquid
products currently registered require this PPE)
Baseline + coveralls, chemical-resistant gloves, chemical-resistant
apron and a respirator.
A closed mixing/loading system, for example, a farm closed mechanical
transfer system for liquids or a packaged based system. Some
engineering controls are not applicable for certain scenarios (e.g., for
handheld application methods there are no known devices that can be
used to routinely lower the exposures).
All the occupational exposure scenarios identified are of short-term duration (i.e., less than
seven days), except for mixing and loading coumaphos for cattle dip vats, which is considered a short-
term and an intermediate-term (i.e., duration is seven days to several months) occupational exposure
scenario. Most of the non-dip vat uses of coumaphos are performed by farmers on their own animals
17
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when arthropod pests become a problem. Mixing and loading liquids for dip vat operations carried out
by USDA-APHIS are not considered chronic exposures. Chronic exposures are exposures of more
than 180 days per year. USDA-APHIS employees who conduct dip vat operations are expected to
be exposed on a daily basis of no more than 60 days.
c. Occupational Handler Risk Summary
In the revised assessment, EPA assessed handler risk using different toxicological endpoints
and uncertainty factors for dermal and inhalation exposures. For coumaphos, the inhalation target
MOB for the short-term and intermediate-term exposures is 300 and the dermal target MOE for short-
term and intermediate-term exposures is 100. These risks were then combined into an Aggregate Risk
Index (ART). This method is used when the uncertainty factors associated with dermal and inhalation
doses of concern are different and the endpoints are the same, i.e., cholinesterase inhibition. ARIs
show how close the total exposure was to the dose at which no adverse effect was observed
(NOAEL), except where no inhalation data were available. In these latter cases, only dermal MOEs
were calculated. Additionally, the risk associated with certain handler exposure tasks were combined
to represent one exposure scenario (e.g., a farmer mixing, loading and applying a spray solution to his
own livestock). All the occupational exposure scenario descriptions, assumptions and estimated risks
presented herein are included in Tables 3-9 of the revised "Occupational Exposure and Risk
Assessment Updating the Coumaphos RED Published August 1996," dated December 28,1999.
Refer to these tables for more information on the assessment.
The following tables summarize the risk concerns after the occupational risk assessment was
revised to include the most current data and assumptions for occupational handlers. The tables
presented in this summary document outline the occupational handler risks at baseline, current PPE, and
provide the risk estimates for each of these scenarios separately with additional PPE and, in some
cases, with engineering controls to show the level of risk mitigation that could be achieved. Note that
ARIs < 1 (for combined exposure), MOEs < 100 (for dermal exposure) and MOEs < 300 (for
inhalation exposure) represent risks of concern for the Agency. More details on the description of each
occupational exposure scenario, data sources and data quality may be found in Tables 3-9 of the
revised "Occupational Exposure and Risk Assessment Updating the Coumaphos RED Published
August 1996," dated December 28,1999.
1) Occupational Handler Risk
The Agency identified eleven major occupational handler scenarios associated with the use of
coumaphos and assessed risks for eight short-term and two intermediate-term exposure scenarios.
However, the Agency did not develop an informational risk assessment for loading dusts into dust bags
due to the lack of surrogate exposure data. The ten scenarios assessed represent twenty-three
combinations of different application methods, formulations, use rates, number of animals/area treated
for the short-term and intermediate-term exposures assessed. Seven of the nine short-term exposure
18
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scenarios and two intermediate-term exposure scenarios pose risk concerns at baseline. ARIs
presented in the tables below represent combined dermal and inhalation MOEs, except for those
exposure scenarios related to the handling of the dust formulation for which no inhalation data were
available. Dermal MOEs corresponding to the handling of dusts are presented in this document for
informational purposes only, because exposure data used to calculate these MOEs were derived from a
vegetable garden exposure scenario, which the Agency believes underestimates exposures to handlers
from dust application to livestock. The exposure scenarios of concern at baseline are listed below and
in Tables 6a and 6b; the number preceding each of them corresponds to the scenario number given in
the occupational risk assessment document
The short-term exposure scenarios of concern at baseline are:
(la) Mixing/loading (M/L) liquids for high pressure handwand (at the application rate for
cattle/horse, handling a volume of 100 gallons/day). ARI for this exposure scenario is
0.57; the risk is driven by dermal exposure.
(Ib) M/L liquids for hydraulic type dip vats (1,800 gal/day). ARI for this exposure scenario
is 0.027; the risk is driven by dermal exposure.
(Ic) M/L liquids for swim dip vats (4,000 gal/day). ARI for this exposure scenario is 0.012;
dermal exposure drives the risk.
(3) Applying liquids for high pressure hand wand (at the application rate for cattle/horse,
handling a volume of 100 gal/day). ARI for this exposure scenario is 0.70; risk is
driven by dermal exposure.
(4) Applying dusts with a shaker can (at the application rate for cattle/horse, treating 50
animals/day; at the application rate for swine, treating 50 animals/ day; and at the
application rate for swine bedding, treating 1000 sq. ft./day). Dermal MOEs for these
exposure scenarios are 27,55, and 41, respectively. Although the dermal MOEs were
estimated based upon exposures from the application of dusts to garden vegetables,
and are likely an underestimate, the Agency believes they provide a reasonable frame
of reference to qualitatively assess risks to applicators from applying dusts to livestock
and swine bedding. No inhalation data were available to assess risks associated with
the application of dusts to livestock.
(5) Mixing/loading/applying (M/L/A) liquids with a low pressure hand wand (at the
application rate for cattle/horse, handling 40 gal/day; and at the application rate for
swine, handling 40 gal/day). ARIs are 0.042 and 0.17, respectively; risks are driven by
the dermal route of exposure.
19
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(6) Loading/applying dust with a mechanical duster (at the application rate for cattle/horse,
treating 50 animals/day; at the application rate for swine, treating 50 animals/day; and at
the application rate for swine bedding, treating 1000 sq. ft./day). Qualitative dermal
MOEs for these exposure scenarios are 27,55, and 41, respectively. No inhalation
data were available to assess risks associated with the application of dusts to livestock.
It should be noted that individual farmers who treat only their own cattle are more likely to have
short-term exposures (i.e., exposures of seven days or less) than other handlers, such as USDA-
APHIS staff, who operate the dip vats and could be exposed to coumaphos multiple times over the
course of one week or several months.
The intermediate-term exposure scenarios of concern at baseline are:
(Ib) M/L liquids for hydraulic type dip vats (450 gal/day), ARI=0.011;
(Ic) M/L liquids for swim dip vats (1000 gal/day), ARI=0.0048.
The risks calculated from these two exposure scenarios are driven by the dermal route of exposure.
20
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2) Post-Application Occupational Risk
The Agency determined that there is likely to be minimal exposure to people contacting treated
animals after application is complete and believes exposure is relatively lower than that to handlers.
Therefore, post-application exposure was not assessed. In addition, current labeling does not permit
contact with treated livestock immediately after application.
B.
Environmental Risk Assessment
This RED Addendum does not include an environmental risk assessment for coumaphos. The
Agency did not conduct a new environmental risk assessment for the effects of coumaphos on non-
target species (e.g., fish, birds, mammals), because we have no reason to believe our conclusions
would change since the 1996 RED.
IV. RISK MANAGEMENT AND REREGISTRATION DECISION
A. Determination of Reregistration Eligibility
Section 4(g)(2)(A) of HFRA calls for the Agency to determine, after submissions of relevant
data concerning an active ingredient, whether products containing the active ingredient are eligible for
reregistration. The Agency has previously identified and required the submission of the generic (i.e.,
active ingredient specific) data to support reregistration of products containing coumaphos as an active
ingredient
In the Coumaphos Reregistration Eligibility Decision (RED) of 1996, the Agency established
that USDA-APHIS uses of coumaphos were eligible for reregistration because the use of this
insecticide is very important to the USDA-APHIS Cattle Fever Tick Eradication Program and the U.S.
economy. USDA estimated the economic significance of the use of coumaphos to be between $1-5
billion dollars per year. With this program, USDA-APHIS has helped in preventing the re-
establishment of the cattle fever tick and its associated disease, piroplasmosis (babesiosis), into the
United States.
EPA also considered the cholinesterase monitoring program currently run by USDA-APHIS in
making the USDA-APHIS uses eligible for reregistration. As part of this program, all APHIS
employees exposed to any carbamate or organophosphate pesticide as a result of handling the pesticide
in concentrated or diluted form, reentering a treated field, or being exposed to drift are required to be
monitored for cholinesterase levels before assuming their duties to establish baseline, and every 60 days
thereafter. If cholinesterase levels in blood serum indicate a significant drop (50 percent or more from
the highest baseline result, regardless of whether it is within the normal range, males: 10.1-22.1 U/ml
and females: 8.3-20U/ml) or an abnormal result (less than 8.0 U/ml), APHIS will relieve the employee
24
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from work involving contact with the pesticide, retest the employee in 30 days and prevent the
employee from returning to work until another sample shows normal cholinesterase levels.
In the 1996 RED, the Agency deferred making a reregistration eligibility decision for
coumaphos uses other than those to control cattle fever tick by USDA-APHIS until chemical-specific
handler studies were submitted and reviewed. These handler studies were required from the registrant
in a generic Data Call-in (DCI) issued as part of the 1996 RED. However, more recently, based on
the small volume and declining trend in the use of coumaphos as livestock and swine bedding animal
treatments, the Agency determined the chemical-specific handler exposure studies were not needed.
The Agency has completed its assessment of the occupational risk associated with the use of
pesticides containing the active ingredient coumaphos, as well as a coumaphos-specific dietary risk
assessment However, the Agency has not yet considered the cumulative effects of organophosphates
as a class. Based on a review of surrogate handler exposure data submitted by the technical registrant,
dietary and handler exposure data available to the Agency and public comments on the Agency's
assessments for the active ingredient coumaphos, EPA has sufficient information on the human health
effects of coumaphos to make a determination of reregistration eligibility for the non-USDA uses and to
make some decisions as part of the tolerance reassessment process under FQPA. Although the
Agency has not yet completed its cumulative risk assessment for the organophosphates, the Agency is
issuing this assessment now in order to identify risk reduction measures that are necessary to allow the
continued use of coumaphos. Appendix B identifies the generic data requirements that the Agency
reviewed as part of its determination of reregistration eligibility of coumaphos, and lists the submitted
studies that the Agency found acceptable.
As a result of its assessment of the remaining risks of coumaphos alone, EPA has determined
that certain uses of coumaphos, unless amended as set forth in this document, present risks inconsistent
with FIFRA. Accordingly, EPA may commence a full risk/benefit analysis, the outcome of which may
indicate that cancellation proceedings are warranted, unless registrants agree to label changes
implementing the risk reduction measures discussed in this reregistration eligibility decisioa At the time
that a cumulative assessment is conducted, the Agency will address any outstanding risk concerns.
However, the Agency may take further actions or require additional studies, if warranted, to finalize the
reregistration eligibility decision for coumaphos after assessing the cumulative risk of the
organophosphate class. Such an incremental approach to the reregistration process is consistent with
the Agency's goal of improving the transparency of the reregistration and tolerance reassessment
processes. By evaluating each organophosphate in turn and identifying appropriate risk reduction
measures, the Agency is addressing the risks from the organophosphates in as timely a manner as
possible.
Since the Agency has not yet completed the cumulative risk assessment for the
organophosphates, this reregistration eligibility decision does not fully satisfy the reassessment of the
existing coumaphos food residue tolerances as called for by the Food Quality Protection Act (FQPA).
25
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When the Agency has completed the cumulative assessment, coumaphos tolerances will be reassessed
in that light. At that time, the Agency will reassess coumaphos along with the other organophosphate
pesticides to complete the FQPA requirements and make a final reregistration determination. By
publishing this reregistration eligibility decision and requiring risk mitigation now for the individual
chemical coumaphos, the Agency is not deferring or postponing FQPA requirements; rather, EPA is
taking steps to assure that uses which exceed FEFRA's unreasonable risk standard do not remain on
the label indefinitely, pending completion of assessment required under the FQPA. This decision does
not preclude the Agency from making further FQPA determinations and tolerance-related rulemakings
that may be required on this pesticide or any other in the future.
If the Agency determines, before finalization of this document, that any of the determinations
described herein are no longer appropriate, the Agency will pursue appropriate action, including but not
limited to, reconsideration of any portion of this document
B. Summary of Phase 5 Comments and Responses
When making its reregistration decision, the Agency took into account all comments received
during Phase 5 of the OP Pilot Process. Comments on risk mitigation were only submitted by the
technical registrant, Bayer Corporation. These comments in their entirety are available in the docket.
A brief summary of the comments and the Agency response is noted here.
Comment. Bayer commented that submitted worker exposure studies and an upcoming environmental
fate study address each of the Agency's identified risk concerns. To address risk concerns associated
with the application of liquid and dust formulations, the registrant has submitted surrogate exposure data
from the Outdoor Residential Exposure Task Force (ORETF), which Bayer believes yield adequate
margins of safety. In addition, Bayer has deleted the use of the mechanical duster from all its dust end-
use products. Regarding the drinking water dietary risk concern presented in the Agency's "Revised
Dietary and Occupational Risk Assessment Update for the Coumaphos RED Published August, 1996,"
Bayer has conducted and will be submitting an absorption/desorption study on coumaphoxon that the
registrant believes will allow the Agency to refine the conservative assumption for the K^. of
coumaphoxon and that this value, in turn, would yield ground water EECs well below the Agency
DWLOCs.
Response. The ORETF study estimated exposure from applying dusts to a garden. The Agency
believes inhalation exposures from applying dust to livestock are likely to be significantly higher than
those resulting from applying dusts to low-growing garden plants. Livestock are tall and move while
dust application is taking place, therefore, livestock are closer to the applicator's breathing zone than
garden plants. Although the Agency has no exposure study with which to estimate the inhalation
exposure likely from applying dust to livestock and swine bedding with a shaker can or loading dust
into dust bags, EPA believes that adding a dust/mist respirator is a prudent risk reduction measure.
26
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Regarding the dietary (drinking water) risk concern, the Agency has revised the drinking water
assessment (please refer to the "Revised Tier 1 Drinking Water Assessment for Coumaphos," dated
June 6,2000) to reflect more realistic environmental fate parameters, and estimated coumaphos
concentrations in ground water do not exceed the chronic DWLOCs. Therefore, the Agency has no
chronic aggregate (food and water) risk concerns at this time. As an additional safely measure, the
Agency and the registrant have agreed that coumaphos solution from dip vat use be disposed of in
concrete-lined pits. The Agency also encourages Bayer to submit the final study report for the
absorption/desorption study on coumaphoxon.
Comment. Bayer commented that, even though it believes adequate margins of safety exist with the
ORETF worker exposure studies, it is willing to implement several risk mitigation measures, such as
limiting the dip vat use of coumaphos to only USDA and maintaining the current label limit of 100
gallons per day for the treatment of livestock with hand held sprayers at the maximum application rate.
Response. The Agency has reviewed risk mitigation measures proposed by Bayer and determined that
these measures would adequately address the Agency's occupational risk concerns associated with the
use of coumaphos in dip vat operations and with the application of liquid formulations as spray using
hand held sprayers. However, additional measures are necessary to mitigate the remaining
occupational risk concerns. These measures are outlined in the "Label Modifications" section of Ihis
document.
C. Regulatory Position
1. FQPA Assessment
a.
"Risk Cup" Determination
As part of the FQPA tolerance reassessment process, EPA assessed the risks associated with
this organophosphate. The assessment was for this individual organophosphate, and does not attempt
to fully reassess these tolerances as required under FQPA. FQPA requires the Agency to evaluate
food tolerances on the basis of cumulative risk from substances sharing a common mechanism of
toxicity, such as the toxicity expressed by the organophosphates through a common biochemical
interaction with the cholinesterase enzyme. The Agency will evaluate the cumulative risk posed by the
entire class of organophosphates once the methodology is developed and the policy concerning
cumulative assessments is resolved.
EPA has determined that risk from exposure to coumaphos is within its own "risk cup." In
other words, if coumaphos did not share a common mechanism of toxicity with other chemicals, EPA
would be able to conclude today that the tolerances for coumaphos meet the FQPA safety standards.
In reaching this determination, EPA has considered the available information on the special sensitivity of
infants and children, as well as the chronic and acute food exposure. An aggregate assessment was
conducted for exposures through food and drinking water. Results of this aggregate assessment
27
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indicate that the human health risks from these combined exposures are within acceptable levels; that is,
combined risks from all exposures to coumaphos "fit" within the individual risk cup. Therefore, the
coumaphos tolerances remain in effect until a full reassessment of the cumulative risk from all
organophosphates is completed, except for those tolerances no longer supported, which will be
revoked.
b. Tolerance Summary
In the individual assessment, tolerances for residues of coumaphos in/on meat, fat, and meat
byproducts [40 CFR § 180.189] are presently expressed in terms of combined residues of parent
coumaphos and its oxygen analog, coumaphoxon. The Agency has determined that no changes to the
milk, cattle, horse and hog tolerances are presently required. Six coumaphos tolerances for residues in
meat, fat, and meat byproducts of goats and sheep should be proposed for revocation, since the
technical registrant no longer supports these uses and has requested voluntary cancellation of these uses
from all its registered product labels.
Table 7. Tolerance Summary for Coumaphos
« ~ - ... ^ " Cunient Tolerance, , Interaj) Tolerance _
, , - Commodity -« "•"- i • Comment
< * >" ppnx -* " TJecjsion^ppirn « ,\ >f.
Tolerances Listed Under 40 CFR §180.189
Cattle, fat
Cattle, MBYP
Cattle, meat
Goats, fat
Goats, MBYP
Goats, meat
Hogs, fat
Hogs, MBYP
Hogs, meat
Horses, fat
Horses, MBYP
Horses, meat
Milk, fat
Sheep, fat
Sheep, MBYP
Sheep, meat
1
1
1
1
1
1
1
1
1
1
1
1
0.5
1
1
1
• 1
1
1
1
1
1
1
1
1
1
1
1
0.5
1
1
1
To be revoked
To be revoked
To be revoked
To be revoked
To be revoked
To be revoked
'Tolerances may only be reassessed upon completion of the cumulative risk assessment of all organophosphates, as required by
FQPA. The tolerances provided in this table are for this single chemical and are supported by all of the submitted residue data.
28
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The Agency will commence proceedings to revoke sk tolerances for sheep and goat (fat,
MBYP, and meat tolerances for each) as soon as the registrant's request has gone through the
voluntary cancellation process, including the publication of notice in the "Federal Register," as
established by HFRA.
On August 16,2000, the Agency established two time-limited tolerances for combined residues
of coumaphos and its oxygen analog, coumaphoxon, in or on honey (0.1 ppm) and beeswax (100
ppm), in response to the emergency exemptions granted under section 18 of FIFRA, authorising the
use of the pesticide in beehives. These tolerances will expire on December 31,2002 (65 FR 49927).
2. Endocrine Disrupter Effects
EPA is required under the FFDCA, as amended by FQPA, to develop a screening program to
determine whether certain substances (including all pesticide active and other ingredients) "may have an
effect in humans that is similar to an effect produced by a naturally occurring estrogen, or other such
endocrine effects as the Administrator may designate." Following the recommendations of its
Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC), EPA determined that
there was scientific basis for including, as part of the program, the androgen and thyroid hormone
systems, in addition to the estrogen hormone system. EPA also adopted EDSTAC's recommendation
that the Program include evaluations of potential effects in wildlife. For pesticide chemicals, EPA will
use FIFRA and, to the extent that effects in wildlife may help determine whether a substance may have
an effect in humans, FFDCA authority to require the wildlife evaluations. As the science develops and
resources allow, screening of additional hormone systems may be added to the Endocrine Disrupter
Screening Program (EDSP).
When the appropriate screening and/or testing protocols being considered under the Agency's
EDSP have been developed, coumaphos may be subjected to additional screening and/or testing to
better characterize effects related to endocrine disruption.
D. Regulatory Rationale
The following is a summary of the rationale for managing risks associated with the use of
coumaphos. Where labeling revisions are imposed, specific language is set forth in the summary tables
of Section V of this document
29
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1. Human Health Risk Mitigation
a. Dietary Risk Mitigation
1) Acute Dietary (Food)
Acute dietary risk from food is well below the Agency's level of concern. A Tier 3 acute dietary
exposure assessment was performed using DEEM™, and analysis yielded a percent acute PAD value
of 21% for the most highly exposed population subgroup, infants < 1 year, at the 99.9th percentile.
Therefore, no risk mitigation measures are necessary at this time to address acute dietary risk from
food.
2) Chronic Dietary (Food)
Chronic dietary risk from food is also well below the Agency's level of concern. A Tier 3
chronic dietary exposure assessment was performed using DEEM™ and analysis yielded a percent
acute PAD value of 13% for the most highly exposed population subgroup, children 1-6 years.
Therefore, no risk mitigation measures are necessary at this time to address chronic dietary risk from
food.
3) Drinking Water
Acute exposure to drinking water from surface or ground water sources is not of concern;
estimated coumaphos concentrations in surface and ground water do not exceed the acute DWLOCs.
No mitigation is necessary at this time to reduce risks resulting from acute drinking water exposure.
Chronic exposure to drinking water from surface water sources is not of concern. In the revised
risk assessment for coumaphos released on April 26,2000, the Agency identified a potential chronic
risk concern from exposures to drinking water derived from groundwater sources. However, the
Agency revised the drinking water assessment to reflect more realistic environmental fate parameters,
and current estimated environmental concentrations of coumaphos in ground water do not exceed the
chronic DWLOCs for any population sub-group. The revised document: "Revised Tier 1 Drinking
Water Assessment for Coumaphos," dated June 6,2000, is available in the OPP Public Docket for
coumaphos.
To further reduce the possibility of groundwater contamination resulting from the disposal of
bioremediated coumaphos spent solution from dip vat operations, the technical registrant agreed to
incorporate the following risk mitigation measure, in addition to existing label requirements:
• Restrict the disposal of bioremediated coumaphos spent solution from dip vat operations
to shallow, concrete-lined evaporation ponds.
30
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b. Occupational Risk Mitigation
To address risk from dermal and inhalation exposures for the handler scenarios presented in
Section in of this document and shown in Tables 6a and 6b of that section, the risk mitigation measures
presented below, in addition to existing label requirements and label modifications established in the
Coumaphos RED of 1996, need to be incorporated into labels.
For the liquid products:
Restrict the use of the 42% flowable product to USDA-APfflS staff enrolled in the
USDA-APHIS cholinesterase monitoring program; and
Maintain the current use restriction on the liquid formulations, limiting the number of
animals an individual may treat with hand held sprayers tolOO head per day at the
maximum application rate, and move this restriction to a more prominent place on the
labels.
At baseline, risks to handlers from mixing/loading and applying liquids for high-pressure hand
wand at the application rate for cattle/horse (ARI=0.057) and at the application rate for swine
(ARJ=0.24) exceed the Agency's level of concern at a higher use rate of 1,000 gallons per day. The
Agency estimates that one gallon of dilute is used per animal. Therefore, the current label restriction on
all liquid products limiting the number of animals an individual can treat with hand held sprayers to 100
head per day at the maximum- application rate needs to be maintained (200 head per day if they are
treated at Vz maximum label rate, etc.").
The use restriction of 100 head per day at the maximum application rate and at currently
required level of personal protection yields occupational risk estimates that are not of concern to the
Agency. ARIs for exposure from mixing/loading of liquids for high-pressure hand wand (scenario la)
and for exposure from applying liquids with high-pressure hand wand (scenario 3) are 52 and 1.4,
respectively. Current liquid product labels require that handlers use chemical-resistant gloves, which is
a protective equipment not considered at baseline.
For the dust products:
• Prohibit the use of mechanical dusters as a method of application for coumaphos technical,
all dust manufacturing-use products and all dust end-use products;
• Require the use of a dust/mist respirator and a chemical-resistant apron on all dust product
labels; and
31
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• Limit the number of animals an individual may treat with dust products by use of a shaker
can to 25 head per day and the swine bedding area treated to 1,000 sq. ft. per day.
The Agency had no handler exposure data to assess dermal and inhalation risks associated with
the application of coumaphos dusts to livestock and swine bedding. However, dermal risk to
applicators based on surrogate exposure studies provided a frame of reference. In the absence of data,
as a prudent safety precaution, EPA has determined that a dusl/mist respirator and a chemical-resistant
apron are necessary to mitigate occupational risks from the use of coumaphos dust products.
E. Label Modifications
The Agency has determined that the coumaphos registration should be amended to mitigate risks
to handlers from use of coumaphos on livestock and swine bedding. The Agency believes the
measures presented above, in addition to existing label requirements, will reduce worker risks of
concern to acceptable levels and that unreasonable adverse effects are unlikely to result from such uses
or practices. In addition, the technical registrant agreed to implement additional risk mitigation
measures to prevent potential groundwater contamination resulting from the disposal of coumaphos
waste solution on non-agricultural land.
The technical registrant does not support the use of coumaphos on sheep and goats and has
indicated its intention to request voluntary cancellation of these two uses from all coumaphos
manufacturing-use and end-use products; therefore, the following measure needs to be incorporated
into labels:
• Restrict the formulation of coumaphos products for use on beef cattle, dairy cattle, horses,
swine and swine bedding uses only.
Provided the risk mitigation measures are incorporated in their entirely into labels for
coumaphos-containing products, the Agency finds that all currently registered uses of coumaphos are
eligible for reregistration, pending a cumulative assessment of the organophosphate pesticides.
F. Other Labeling Modifications
In order to be eligible for reregistration, other use and safety information need to be placed on
the labeling of all end-use products containing coumaphos. For the specific labeling statements, refer to
Table 8 in Section V of this document
32
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1. Endangered Species Statement
The Agency has developed a program ("The Endangered Species Protection Program") to
identify pesticides whose use may cause adverse impacts on endangered and threatened species and to
implement mitigation measures that will eliminate the adverse impacts. At present, the program
provides information to users to help them protect these species on a voluntary basis. As currently
planned, the final program will call for label modifications referring to limitations on pesticide uses,
typically as depicted in county-specific bulletins or by other site-specific mechanisms as specified by
state partners. A final program will be described in a future "Federal Register" notice. The Agency is
not imposing label modifications at this time through the RED. Rather, any requirements for product
use modification will occur in the future under the Endangered Species Protection Program.
V. WHAT REGISTRANTS NEED TO DO
A. Manufacturing-Use Products
7
In order to be eligible for reregistration, registrants need to implement the risk mitigation
measures outlined in Section IV, by submitting label amendments and meeting the data requirements
described in this section.
1. Additional Generic Data Requirements
The generic data base supporting the reregistration of coumaphos for the above eligible uses has
been reviewed and determined to be essentially complete. The following data gap remains:
• Developmental Neurotoxicity Study, Guideline No. 870.6300
A Data Call-In Notice (DCI) sent on September 10,1999 to registrants of organophosphate
pesticides currently registered under FIFRA (August 6,1999 64FR42945-42947, August 18,1999
64FR44922-44923). DCI requirements included acute, subchronic, and developmental neurotoxicity
studies; due dates are 9/2001. The technical registrant of coumaphos requested a generic data waiver
to the developmental neurotoxicity study, and the Agency denied such request in a letter dated March
10,2000. Currently, the registrant intends to support the registration of coumaphos and has committed
to submit the required developmental neurotoxicity study. As stated in the Agency's March 10 letter to
Bayer Corporation, the DCI issued in September 1999 supercedes previous chemical-specific
determinations that may have been rendered by the Agency. The Agency acknowledges that the
revised risk assessments and supporting documents for coumaphos contain outdated statements that a
developmental neurotoxicity study in rats is not required. These statements are not correct. The
toxicology data base for coumaphos has not been completely fulfilled, and the developmental
neurotoxicity study is still required.
33
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2. Labeling for Manufacturing-Use Products
To remain in compliance with FTFRA, manufactuiing-use product (MPs) labeling should be
revised to comply with all current EPA regulations, PR Notices and applicable policies. In addition,
labeling changes are necessary to implement measures outlined in Section IV above.
The Agency is reviewing revised labeling submitted by the registrants in response to the label
changes outlined in the 1996 Coumaphos RED to determine which additional modifications are needed
to reflect the reregistration conditions specified in this RED Addendum. The Agency will contact the
registrants if label changes, other than the ones already implemented, are necessary. Therefore,
registrants do not need to submit applications for amended registrations or draft labels at this time. The
Special Review and Reregistration Division contact for product reregistration is Moana Appleyard.
Her phone number is (703) 305-5428.
B. End-Use Products
1. Additional Generic Data Requirements
Section 4(g)(2)(B) of FIFRA calls for the Agency to obtain any needed product-specific data
regarding the pesticide after a determination of eligibility has been made. This RED Addendum does
not contain a product-specific data call-in, since it was issued in the 1996 Coumaphos RED.
2. Labeling for End-Use Products
Labeling changes are necessary to implement measures outlined in Section IV above. Specific
language to implement these changes is specified in Table 8 at the end of this section. The Agency is
reviewing revised labeling submitted by the registrants in response to the label changes outlined in the
1996 Coumaphos RED to determine which additional modifications are needed to reflect the
reregistration conditions specified in this RED Addendum. The Agency will contact the registrants if
label changes, other than the ones already implemented, are necessary. Therefore, registrants do not
need to submit applications for amended registrations or draft labels at this time. The Special Review
and Reregistration Division contact for product reregistration is Moana Appleyard. Her phone number
is (703) 305-5428.
C. Existing Stocks
Registrants may generally distribute and sell products bearing old labels/labeling for 12 months
from the date of the issuance of this Reregistration Eligibility Decision Addendum document. Persons
other than the registrant may generally distribute or sell such products for 24 months from the date of
the issuance of this document. However, existing stocks time frames will be established case-by-case,
34
-------
depending on the number of products involved, the number of label changes, and other factors. Refer
to "Existing Stocks of Pesticide Products; Statement of Policy"; "Federal Register", Volume 56, No.
123, June 26,1991.
The Agency has determined that registrant may distribute and sell coumaphos products bearing
old labels/labeling for 12 months from the date of issuance of this RED Addendum. Persons other than
the registrant may distribute or sell such products for 24 months from the date of the issuance of this
document. Registrants and persons other than the registrant remain obligated to meet pre-existing
Agency imposed label changes and existing stocks requirements applicable to products they sell or
distribute.
35
-------
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-------
VL RELATED DOCUMENTS AND HOW TO ACCESS THEM
This Reregistration Eligibility Decision Addendum is supported by documents that are presently
maintained in the OPP docket The OPP docket is located in Room 119, Crystal Mall #2,1921
Jefferson Davis Highway, Arlington, VA. It is open Monday through Friday, excluding legal holidays
from 8:30 am to 4 pm.
The docket initially contained preliminary risk assessments and related documents as of
September 2,1999. Sixty days later the first public comment period closed. The EPA then considered
comments, revised the risk assessment, and added the formal "Response to Comments" document and
the revised risk assessment to the docket on April 26,2000.
All documents, in hard copy form, may be viewed in the OPP docket room or downloaded or
viewed via the Internet at the following site: "http://www.epa.gov/pesticides/op/."
44
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VH. APPENDICES
45
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46
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Appendix A. TABLE OF USE PATTERNS ELIGIBLE FOR REREGISTRATION
Site
Application Type
Formulation
%AI
Max. Single
Application
Rate
(Ibai/gal)
Max.*
Apps
Restrictions/Comments
Food Uses
Beef and Non-Lactating Daily Cattle
Dip vat treatment
Spray treatment
Spray treatment
Spray treatment
Backrubber treatment
Backrubber treatment
Dust bag treatment
42Ib/gal
Flowable
4.2Ib/gal
Flowable
l.OIb/gal
EC
0.5 Ib/gal
EC
l.OIb/gal
EC
0.5 Ib/gal
EC
l%ai bulk dust
0.025 Ib/gal
0.021 Ib/gal
0.029 Ib/gal
0.02 Ib/gal
0.076 Ib/gal
fuel oil
0.038 Ib/gal
fuel oil
N/A
2/year
6/year
Not
specified
6/year
Not
specified
Not
specified
Not
specified
Use of this formulation is restricted
to USDA-APfflS staff enrolled in
theUSDA-APHIS Cholinesterase
Monitoring Program. Animals
should not be dipped more than
twice per year unless additional
treatments are required by APHIS
Veterinary Services
Regulations/Memoranda for Animals
included in the Federal Eradication
Programs.
Individuals must limit the number of
animals they treat per day with hand
held sprayers to no more than 100, if
the animals are treated at the
maximum application label rate, 200
if they are treated at 1A maximum
label rate, etc.
Individuals must limit the number of
animals they treat per day with hand
held sprayers to no more than 100, if
the animals are treated at the
maximum application label rate, 200
if they are treated at Vz maximum
label rate, etc.
Individuals must limit the number of
animals they treat per day with hand
held sprayers to no more than 100, if
the animals are treated at the
maximum application label rate, 200
if they are treated at 54 maximum
label rate, etc.
47
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•Site
Application Type
Shaker can treatment
Shaker can treatment
Formulation
%AI
l%ai bulk dust
l%ai shaker can
Max. Single
Application
Rate
(Ibai/gal)
0.0013 Ib
ai/animal
0.0013 Ib
ai/animal
Max.#
Apps
12/year
12/year
Restrictions/Comments
Individuals must limit the number of
animals they may treat with shaker
can to no more than 25 head per day.
Individuals must limit the number of
animals they may treat with shaker
can to no more than 25 head per day.
Lactating Dairy Cattle
Spray treatment
Spray treatment
Dust bag treatment
l.OIb/gal
EC
0.5Ib/gal
EC
l%ai bulk dust-
0.0024 Ib/gal
0.01 Ib/gal
N/A
Not
specified
6/year
Not
specified
Individuals must limit the number of
animals they treat per day with hand
held sprayers to no more than 1 00, if
the animals are treated at the
maximum application label rate, 200
if they are treated at Vi maximum
label rate, etc.
Individuals must limit the number of
animals they treat per day with hand
held sprayers to no more than 1 00, if
the animals are treated at the
maximum application label rate, 200
if they are treated at 1A maximum
label rate, etc.
48
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Site
Application Type
Formulation
%AI
Max. Single
Application
Rate
(Ibai/gal)
Max.#
Apps
Restrictions/Comments
Horses
Spray treatment
Spray treatment
Spray treatment
4.2 Ib/gal
Flowable
l.OIb/gal
EC
0.5 to/gal
EC
0.021 Ib/gal
0.029 Ib/gal
0.021b/gal
6/year
Not
specified
6/year
Individuals must limit the number of
animals they treat per day with hand
held sprayers to no more than 100, if
the animals are treated at the
maximum application label rate, 200
if they are treated at '/2 maximum
label rate, etc.
Individuals must limit the number of
animals they treat per day with hand
held sprayers to no more than 100, if
the animals are treated at the
maximum application label rate, 200
if they are treated at V4 maximum
label rate, etc.
Individuals must limit the number of
animals they treat per day with hand
held sprayers to no more than 100, if
the animals are treated at the
maximum application label rate, 200
if they are treated at Vz maximum
label rate, etc.
49
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Site
Application Type
Formulation
%AI
Max. Single
Application
Rate
(Ibai/gal)
Max.*
Apps
Restrictions/Comments
Swine
Spray treatment
Spray treatment
Shaker can treatment
Bedding treatment
Shaker can treatment
l.Olb/gal
EC
0.5Ib/gal
EC
l%ai bulk dust
l%ai bulk dust
1% ai shaker can
0.005 Ib/gal
0.005 Ib/gal
0.000625 Ib
ai/animal
0.042 Ib
ai/1000 sq.
ft.
0.000625 Ib
ai/aninisl
Not
specified
6/year
6/year
6/year
6/year
Individuals must limit the number of
animals they treat per day with hand
held sprayers to no more than 100, if
the animals are treated at the
maximum application label rate, 200
if they are treated at '/£ maximum
label rate, etc.
Individuals must limit the number of
animals they treat per day with hand
held sprayers to no more than 100, if
the animals are treated at the
maximum application label rate, 200
if they are treated at '/£ maximum
label rate, etc.
Individuals must limit the number of
animals they may treat with shaker
can to no more than 25 head per day.
Individuals must limit the number of
animals they can treat per day with
shaker can to no more than l,000sq.
ft per day.
Individuals must limit the number of
animals they may treat with shaker
can to no more than 25 head per day.
50
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Appendix B. DATA SUPPORTING GUIDELINE REQUIREMENTS FOR THE
REREGISTRATION OF COUMAPHOS
GUIDE TO APPENDIX B
Appendix B contains listing of data requirements which support the reregistration for active
ingredients within case #0018 (coumaphos) covered by this RED Addendum. It contains generic data
requirements that apply to coumaphos in all products, including data requirements for which a "typical
formulation" is the test substance.
The data table is organized in the following formats:
1. Data Requirement (Column 1). The data requirements are listed in the order in which
they appear in 40 CFR part 158. the reference numbers accompanying each test refer
to the test protocols set in the Pesticide Assessment Guidance, which are available from
the National technical Information Service, 5285 Port Royal Road, Springfield, VA
22161 (703) 487-4650.
2. Use Pattern (Column 2). This column indicates the use patterns for which the data
requirements apply. The following letter designations are used for me given use
patterns.
A. Terrestrial food
B. Terrestrial feed
C. Terrestrial non-food
D. Aquatic food
E. Aquatic non-food outdoor
F. Aquatic non-food industrial
G. Aquatic non-food residential
H. Greenhouse food
I. Greenhouse non-food
J. Forestry
K. Residential
L. Indoor food
M. Indoor non-food
N. Indoor medical
O. Indoor residential
3. Bibliographic Citation (Column 3). If the Agency has acceptable data in its files, this
column list the identify number of each study. This normally is the Master Record
Identification (MRDD) number, but may be a "GS" number if no MRED number has
been assigned. Refer to the Bibliography appendix for a complete citation of the study.
51
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52
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56
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Appendix C LIST OF AVAILABLE RELATED DOCUMENTS
These documents are available from the Public Docket Office or at the following web site:
www.epa.gov/pesticides/op/coumaphosJitm
5) Hazard Assessment of the Organophosphates
6) FQPA Safely Factor Recommendations for the Organophosphates
7) Frequently Asked Questions
8) Federal Register Notice Vol. 65, Number 81, Pages 24468-24469 (Comment period ending
June 26,2000)
9) Federal Register Notice Vol. 64, Number 170, Pages 48164-48165 (Comment period
ending November 1,1999)
10) Transmittal Letter to Bayer Corporation Regarding the Preliminary Risk Assessment
11) Preliminary Dietary and Occupational Risk Assessment
12) Revised Dietary and Occupational Risk Assessment
13) Preliminary Acute and Chronic Dietary Exposure and Risk Analyses
14) Addendum to the Acute and Chronic Dietary Exposure and Risk Analysis
15) Revised Acute and Chronic Dietary Exposure and Risk Analyses
16) Addendum to the Acute Dietary Exposure Analysis for Coumaphos
17) Preliminary Occupational Exposure and Risk Assessment
18) Revised Occupational Exposure and Risk Assessment
19) Addendum to the Occupational Exposure and Risk Assessment
20) Tier 1 Drinking Water Assessment for Land Farming of Bioremediated Coumaphos from Cattle
Dips
21) Revised Tier 1 Drinking Water Assessment for Coumaphos
22) Report of the FQPA Safety Factor Committee
23) Report of the Hazard Identification Assessment Review Committee
24) Percent Dairy Cattle Treated with Coumaphos
25) Quantitative Usage Analysis for Coumaphos
26) Coumaphos Summary
27) Overview of Coumaphos Revised Risk Assessments
28) Registrant's Response to EPA's Letter Transmitting me Preliminary Risk Assessment
29) EPA's Response to the Registrant's Error Comments
30) HED's Response to Public Comments
31) EPA's Response to Public Comments
57
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58
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Appendix D. CITATIONS SUPPORTING THE REREGISTRATION ELIGIBILITY
DECISION ADDENDUM AND FQPA TOLERANCE REASSESSMENT
PROGRESS REPORT (BIBLIOGRAPHY)
GUIDE TO APPENDIX D
1. CONTENTS OF BIBLIOGRAPHY. This bibliography contains citations of all studies
considered relevant by EPA in arriving at the positions and conclusions stated elsewhere in the
Reregistration Eligibility Document. Primary sources for studies in this bibliography have been
the body of data submitted to EPA and its predecessor agencies in support of past regulatory
decisions. Selections from other sources including the published literature, in those instances
where they have been considered, are included
2. UNTTS OF ENTRY. The unit of entry in this bibliography is called a "study." In the case of
published materials, this corresponds closely to an article. In the case of unpublished materials
submitted to the Agency, the Agency has sought to identify documents at a level parallel to the
published article from within the typically larger volumes in which they were submitted. The
resulting "studies" generally have a distinct title (or at least a single subject), can stand alone for
purposes of review and can be described with a conventional bibliographic citation. The
Agency has also attempted to unite basic documents and commentaries upon them, treating
them as a single study.
3. 1DENTMCATION OF ENTRIES. The entries in this bibliography are sorted numerically by
Master Record Identifier, or "MRID" number. This number is unique to the citation, and should
be used whenever a specific reference is required. It is not related to the six-digit "Accession
Number" which has been used to identify volumes of submitted studies (see paragraph 4(d)(4)
below for further explanation). In a few cases, entries added to the bibliography late in the
review may be preceded by a nine character temporary identifier. These entries are listed after
all MRID entries. This temporary identifying number is also to be used whenever specific
reference is needed.
4. FORM OF ENTRY. In addition to the Master Record Identifier (MRID), each entry consists
of a citation containing standard elements followed, in the case of material submitted to EPA, by
a description of the earliest known submission. Bibliographic conventions used reflect the
standard of the American National Standards Institute (ANSI), expanded to provide for certain
special needs.
a Author. Whenever the author could confidently be identified, the Agency has chosen to
show a personal author. When no individual was identified, the Agency has shown an
identifiable laboratory or testing facility as the author. When no author or laboratory
could be identified, the Agency has shown the first submitter as the author.
59
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b.
c.
d.
Document date. The date of the study is taken directly from the document. When the
date is followed by a question mark, the bibliographer has deduced the date from Hie
evidence contained in the document. When the date appears as (1999), the Agency
was unable to determine or estimate the date of the document.
Title. In some cases, it has been necessary for the Agency bibliographers to create or
enhance a document title. Any such editorial insertions are contained between square
brackets.
Trailing parentheses. For studies submitted to the Agency in the past, the trailing
parentheses include (in addition to any self-explanatory text) the following elements
describing the earliest known submission:
(1) Submission date. The date of the earliest known submission appears
immediately following the word "received."
(2) Administrative number. The next element immediately following the word
"under" is the registration number, experimental use permit number, petition
number, or other administrative number associated with the earliest known
submission.
(3) Submitter. The third element is the submitter. When authorship is defaulted to
the submitter, this element is omitted.
(4) Volume Identification (Accession Numbers). The final element in the trailing
parentheses identifies the EPA accession number of the volume in which the
original submission of the study appears. The six-digit accession number
follows the symbol "CDL," which stands for "Company Data Library." This
accession number is in turn followed by an alphabetic suffix which shows the
relative position of the study within the volume.
60
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BIBLIOGRAPHY
MRID CITATION
00110597 Shmidl, J.; Rainey, L.; Kohlenberg, M. (1981) Oral LD50 Evaluation for Coumaphos
Compound: Report No. 72212. (Unpublished study received on unknown date under
11556-4; submitted by Bayvet, Shawnee Mission, KS; CDL:248200-B)
00110598 Shmidl, J.; Kohlenberg, M.; Rainey, L. (1981) Dermal LD50 Evaluation for
Coumaphos Technical Compound: Report No. 72216. (Unpublished study received
on unknown date under 11556-4; submitted by Bayvet, Shawnee Mission, KS;
CDL:248200-C)
00110599 Shmidl, J.; Kohlenberg, M.; Rainey, L. (1981) Eye Irritation Evaluation for Coumaphos
Technical in Rabbits: Report No. 72213. (Unpublished study received on unknown
date under 11556-4; submitted by Bayvet, Shawnee Mission, KS; CDL:248200-D)
00110600 Shmidl, I; Kohlenberg, M.; Rainey, L. (1981) Primary Dermal Irritancy of Coumaphos
Technical to Rabbits: Report No. 72205. (Unpublished study received on unknown
date under 11556-4; submitted by Bayvet, Shawnee Mission, KS; CDL:248200-E)
00110601 Sangha, G.; De Jong, M.; Lamb, D.; et al. (1982) Acute Inhalation Toxieity Study with
Coumaphos Technical in Rats: Study No. 81-041-14, Report No. 72398.
(Unpublished study received on unknown date under 11556-4; submitted by Bayvet,
Shawnee Mission, KS; CDL:248200-F)
00110602 Shmidl, J.; Kohlenberg, M.; Hess, L. (1982) Dermal Sensitization Evaluation of
Coumaphos Technical in Guinea Pigs: Report No. 72452. (Unpublished study
received on unknown date under 11556-4; submitted by Bayvet, Shawnee Mission,
KS; CDL:248200-G)
00115167 Kruckenberg, S. (1981) Acute Delayed Neurotoxicity of Coumaphos in
Hens-81-Chicken-02: [Submitter] 72206. (Unpublished study received Sep 23,
1982 under 11556-11; prepared by Kansas State Univ., Veterinary Medical Center,
Dept of Pathology, submitted by Bayvet, Shawnee Mission, KS; CDL:248397-A)
00126527 Porter, M.; Jasty, V.; Bare, J.; et al. (1983) Subchronic (13 Week) Oral Toxieity
Evaluation of Coumaphos in the Rat: Bayvet Report No. 72586. (Unpublished study
received Mar 21,1983 under 11556-11; prepared in cooperation with Miles
Laboratories, submitted by Bayvet, Shawnee Mission, KS; CDL:249746-A)
61
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BIBLIOGRAPHY
MRID
00131684
00159928
263038
41117401
41117403
41778501
41778502
41847501
42084901
42097401
42097402
CITATION
Clemens, G.; Hartnagel, R. (1983) Study of the Toxicity of Coumaphos: ffl. Teratology
(Segment n) Study in the Rat: Report No. 8; 72754. (Unpublished study received Oct
18,1983 under 11556-11; prepared by Miles Laboratories, Inc., submitted by Bayvet,
Shawnee Mission, KS; CDL:251532-E)
Waggoner, T. (1986) Hydrolysis of pCarbon 14a Coumaphos in Sterile Buffered
Aqueous Solutions: Report No. 73320. Unpublished study prepared by Pharmacology
and Toxicology Research Laboratory. 118 p.
See MRID #159928
Shoup, R. (1989) Rabon Oral Larvicide Manufacturing Base: Product Identity and
Composition. Unpublished study prepared by Fermenta Animal Health Co. 16 p.
Shoup, R. (1989) 75% Rabon Insecticide Wettable Powder: Product Identity and
Composition. Unpublished study prepared by Fermenta Animal Health Co. 16 p.
Rose, W. (1990) Co-Ral 25% Dust Base (Coumaphos): Lab Project Number: 74114;
74115. Unpublished study prepared by Mobay Corp. 77 p.
Rose, W. (1990) Product Chemistry of Coumaphos Technical Grade 1: Lab Project
Number: 74111; 74113; 72899. Unpublished study prepared by Mobay Corporation.
98 p.
Putman, D. (1991) Micronucleus Cytogenetic Assay in Mice: Coumaphos Technical:
Lab Project Number: T9423/122. Unpublished study prepared by Microbiological
Associates, Inc. 36 p.
Sheets, L.; Phillips, S. (1991) Repeated Dose (21-Day) Dermal Toxicity Study with
Technical Grade Coumaphos in Rats: Lab Project Number: 91-122-IE. Unpublished
study prepared by Mobay Corp. 253 p.
Waggoner, T. (1991) Coumaphos: Adsorption/Desorption of Two Degradation
Products: Chlorferon and HOL-5461: Lab Project Number: COUM91E: COUM91D.
Unpublished study prepared by M. C. Bownam and Associates. 101 p.
Waggoner, T. (1991) Coumaphos: Nature of the Residue: Lab Project Number:
9014B. Unpublished study prepared by Southwest Bio-Labs, Inc. 138 p.
62
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BIBLIOGRAPHY
MRID CITATION
42097403 Waggoner, T. (1991) Coumaphos: Residue Analytical Methods: Lab Project Number:
MOBAY-MR-1: MOB AY-MR-1 A. Unpublished study prepared by M. C. Bowman
and Associates. 86 p.
42254501 Goethem, D. (1992) Micronucleus Cytogenetic Assay in Mice: Lab Project Number:
T9423.122. Unpublished study prepared by Microbiological Associates, Inc. 9 p.
42258601 Basel, C. (1992) Analysis of Five Lots of Co-Ral 25 Percent Dust Base and Five Lots
of Coumaphos Technical: Lab Project Number: 92-624-009... 127. Unpublished study
prepared by Miles, Inc. 29 p.
42323401 Waggoner, T. (1992) Coumaphos: Residue Chemistry: Residue Analytical Methods:
Lab Project Number: COUM91H: COUM91H1. Unpublished study prepared by
M.C. Bowman and Associates and Miles, Inc. 74 p.
42323402 Waggoner, T. (1992) Coumaphos: Residue Chemistry: Nature of the Residue: Lab
Project Number: 74311: COUM92E. Unpublished study prepared by M.C. Bowman
and Associates and Miles, Inc. 29 p.
42378501 Brannan, C. (1992) Supplemental Submission to MRID No. 417785-01: Product
Identity and Composition of Coumaphos Technical Grade 1. Unpublished study
prepared by Miles Inc. 10 p.
42378502 Thomas, L. (1992) Progress Report on the Identification of Substances Associated
with Coumaphos in Co-Ral 25% Dust Base/Wettable Powder and Coumaphos
Technical: Lab Project Number: 92-618-016:92-618-023:92-619-035. Unpublished
study prepared by Miles Inc. 25 p.
42512601 Judy, D.; Kaiser, F. (1992) Removal of Coumaphos Active Ingredient from Cattle
Hides Treated with Co-Ral Emulsifiable Liquid Insecticide (E.L.I.): Lab Project
Number: 40329. Unpublished study prepared by ABC Labs, Inc. 117 p.
42512602 Judy, D.; Kaiser, F. (1992) Removal of Coumaphos Active Ingredient from Cattle
Hides Treated with Co-Ral 25% Wettable Powder Insecticide: Lab Project Number:
40418. Unpublished study prepared by ABC Labs, Inc. 112 p.
42512603 Shmidl, J. (1992) Coumaphos: Field Testing-Birds. Unpublished study prepared by
Cornell Lab of Ornithology. 52 p.
63
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BIBLIOGRAPHY
MRID CITATION
42512604 Com, J.; Nettles, V. (1992) Coumaphos: Pilot Field Study to Evaluate Potential
Toxicologic Effects in Wild Birds by Coumaphos Applications to Livestock: Lab
Project Number: SCWDS-001. Unpublished study prepared by The Univ. of
Georgia. 51 p.
42666401 Astroff, A. (1993) Repeated Dose (21 Day) Dermal Toxicity Study with Technical
Grade Coumaphos in Rats: Supplemental To MRID 42084901: Lab Project Number:
91-122-IE. Unpublished study prepared by Miles Inc. 20 p.
42675001 Basel, C. (1993) Identification of Three HPLC Peaks of Unknown Impurities
Associated with Coumaphos: Lab Project Number: 93-633-107: 74386. Unpublished
study prepared by Bayer AG. 30 p.
42675003 Thomas, L. (1993) Analysis of 5 Lots of Co-Ral 25% Dust Base and 5 Lots of
Coumaphos Technical: Revised Report: Lab Project Number: 92-624-009:
92-619-035:74284. Unpublished study prepared by Miles Inc. 40 p.
42764101 Dykes, J. (1993) Determination of the Aqueous Photodegradation of (carbon
14)-Coumaphos: Revised Final Report: Lab Project Number: 1224: 1224-1:74413.
Unpublished study prepared by Analytical Development Corp. 81 p.
42764102 Dykes, J. (1993) Determination of the Aqueous Photodegradation of (carbon
14)-Coumaphos: Addendum No. 1 to Revised Final Report: Lab Project Number:
1224:1-1224:74413-1. Unpublished study prepared by Analytical Development
Corp. 9 p.
42920301 Dykes, J. (1993) Determination of the Photodegradation of (14-C) Coumaphos on the
Surface of Soil: Lab Project Number: ADC 1223. Unpublished study prepared by
Analytical Development Corporation. 82 p.
43022101 Kelley, I; Wood, S. (1993) Aqueous Photolysis of Coumaphos-Identification of the
Main Degradate: A Study to Supplement Miles Report 74413: Lab Project Number:
106221: CS082401. Unpublished study prepared by Miles Inc. Agricultural Div. 43
P-
43055301 Jones, R.; Elcock, L.; Dass, P.; et al. (1993) Chronic Feeding Toxicity Study of
Technical Grade Coumaphos in Beagle Dogs: Lab Project Number: 91-276-JP:
74459. Unpublished study prepared by Miles, Inc. 1487 p.
64
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BIBLIOGRAPHY
MRID CITATION
43061701 Eigenberg, D.; Elcock, L. (1993) A Two-generation Dietary Reproduction Study in
Rats Using Technical Grade Coumaphos: Lab Project Number: 91-672-JI: 74460.
Unpublished study prepared by Miles, Inc. 1044 p.
43066301 Gagliano, G.; Bowers, L. (1993) Early Life Stage Toxicity of
(carbon-14)-Coumaphos to the Rainbow Trout (Oncorhynchus mykiss) Under
Flow-Through Conditions: Lab Project Number: 106245: CS842201. Unpublished
study prepared by Miles Inc. 70 p.
43103901 Kelley, L; Wood, S. (1994) Aqueous Photolysis of Coumaphos-Identification of the
Main Degradate: Lab Project Number: CS082401: 106221. Unpublished study
prepared by Miles Agricultural Division. 43 p.
43115801 Siemann, L. (1993) Product Chemistry for Coumaphos: Lab Project Number: 74462:
3537-F. Unpublished study prepared by Midwest Research Institute. 29 p.
43116601 Gagliano, G.; Fuss, M. (1994) Chronic Toxicity of (carbon 14)-Coumaphos to
Dapbnia magna Under Static Renewal Conditions: Lab Project Number: CS840701:
106410. Unpublished study prepared by Miles, Inc. 57 p.
43123401 Bajzik, M. (1994) The Independent Laboratory Method Validation for the Analysis of
Coumaphos and its Oxygen Analog in Meat and Milk: Lab Project Number:
A012.005: 74473. Unpublished study prepared by Huntingdon Analytical Services.
102 p.
43167401 Dykes, J. (1994) Determination of the Photodegradation of (carbon 14>Coumaphos
on the Surface of Soil: Characterization of Bound Residues and Radioactivity Loss:
Revision #1 to Final Research Report: Lab Project Number: 1223H-1: 74476.
Unpublished study prepared by Analytical Development Corp. 33 p.
43569801 Fought, L. (1994) Coumaphos Residues in Cattle Treated with CO-RAL 25%
Wettable Powder Revised: Lab Project Number: 10820: KC-212-62D. Unpublished
study prepared by Miles, Inc. 7 p.
43569802 Fought, L. (1994) Coumaphos Residues in Cattle Exposed to a Backrubber Prepared
from CO-RAL Emulsifiable Livestock Insecticide: Revised: Lab Project Number
13912: KC-201-64D. Unpublished study prepared by Miles, Inc. 9 p.
65
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BIBLIOGRAPHY
MRID CITATION
43569803 Fought, L. (1994) Coumaphos Residues in the Milk of Cattle Treated with CO-RAL
Emulsifiable Livestock Insecticide: Revised: Lab Project Number 24050:
KC-200-68D. Unpublished study prepared by Miles, Inc. 45 p.
43569804 Fought, L. (1994) Coumaphos Residues in the Fat of Cattle Treated with CO-RAL
Emulsifiable Livestock Insecticide: Revised: Lab Project Number: 26083. Unpublished
study prepared by Miles, Inc. 13 p.
43569805 Fought, L. (1994) Coumaphos Residues in the Fat of Cattle Treated with CO-RAL
25% Wettable Powder: Revised: Lab Project Number: 26084. Unpublished study
prepared by Miles, Inc. 13 p.
43569806 Fought, L. (1994) Coumaphos Residues in the Fat of Cattle Treated with CO-RAL
Insecticide Pour-On: Revised: Lab Project Number: 26107. Unpublished study
prepared by Miles, Inc. 13 p.
43569807 Fought, L. (1994) Coumaphos Residues in the Fat of Cattle Treated with CO-RAL
25% Wettable Powder Revised: Lab Project Number: 27484: AH-70A-743.
Unpublished study prepared by Miles, Inc. 20 p.
43569808 Fought, L. (1994) Coumaphos Residues in the Fat of Cattle Treated with CO-RAL
Insecticide Pour-On: Revised: Lab Project Number: 27486: AH-70A-749.
Unpublished study prepared by Miles, Inc. 13 p.
43569809 Fought, L. (1994) Coumaphos Residues in the Fat of Cattle Dipped in a 50%
Formulation of CO-RAL Wettable Powder: Revised: Lab Project Number. 40856:
AH-74A-932. Unpublished study prepared by Miles, Inc. 25 p.
43569810 Fought, L. (1994) Coumaphos Residues in the Tissues of Cattle Treated with a 3%
Formulation of K.R.S. with CO-RAL Spray Foam Insecticide: Revised: Lab Project
Number: 50836: TR-76A-116. Unpublished study prepared by Miles, Inc. 31 p.
44252901 Niven, KJM et al. (1993) Occupational Hygiene Assessment of Sheep Dipping
Practices and Processes.
44252902 Niven, KJM et al. (1996) Occupational Hygiene Assessment of Exposure to
Insecticide and the Effectiveness of Protective Clothing During Sheep Dipping
Operations.
66
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BIBLIOGRAPHY
MRID CITATION
44296901 Lunchick, C. (1997) Reassessment of Operator Exposure and Risk for the Animal
Spray and Dip Uses of Coumaphos: Lab Project Number: 74852. Unpublished study
prepared by Jellinek, Schwartz & Connolly, Inc. 94 p.
44518501 Merricks, D. (1998) Carbaryl Mker/Loader/Applicator Exposure Study During
Application of RP-2 Liquid (21%) to Fruit Trees and Ornamental Plants: Lab Project
Number: 1518. Unpublished study prepared by Agrisearch Inc., Rhone-Poulenc Ag
Co., and Morse Laboratories, Inc. 320 p.
44544801 Dreist, M.; Popp, A. (1998) Acute Oral Neurotoxicity Screening Study in Wistar Rats:
Coumaphos: Lab Project Number: PH-27054: T 4061287: 74961. Unpublished study
prepared by Bayer AG. 441 p.
44749401 Sheets, L.; Gastner, M. (1999) Repeated-Dose (Two-and Five-Day Exposure) .
Dermal Toxicity Study with Technical Grade Coumaphos in Rats: Lab Project Number.
97-122-NT. Unpublished study prepared by Bayer Corporation. 48 p.
44775901 Dreist, M.; Popp, A. (1998) Coumaphos: Subchronic Neurotoxicity Screening Study in
Wistar Rats (Thirteen Week Administration in the Diet): Lab Project Number:
PH-28342: T 3061060:75026. Unpublished study prepared by Bayer Ag. 485 p.
44972201 Klonne, D. (1999) Integrated Report for Evaluation of Potential Exposures to
Homeowners and Professional Lawn Care Operators Mixing, Loading, and Applying
Granular and Liquid Pesticides to Residential Lawns: Lab Project Number: OMAOO5:
OMAOO1: OMAOO2. Unpublished study prepared by Ricerca, Inc., and Morse
Laboratories. 2213 p.
45129601 Mihlan, G.J. (2000) Reassessment of Operator Exposure and Risk for the Uses of
Coumaphos. Bayer Report No. 75217. Unpublished study prepared by Bayer .
Corporation. 28 p.
67
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BIBLIOGRAPHY
CITATION
The following studies do not have MRE) Numbers:
Kurta, D.A. and W.M. Bode. (1985). Applicator Exposure to the Home Gardener.
American Chemical Society Symposium Series 273, Washington, DC.
Livestock Spraying Practices Survey. (1996). Bayer Animal Health. Vance
Publishing. Attachment of MRID 44296901.
68
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AppendkE. LIST OF REGISTRANTS
Technical Registrant:
Contact:
Address:
Telephone Number:
Bayer Corporation, Agriculture Division, Animal Health
F. Terry McNamara
Bayer Corporation
P.O. Box 390
Shawnee Mission, KS 66201-0390
(913)631-4800
69
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.United States! '
Environmental Protection
Agency
*
Office giW^r (4204)
.V^gShit^jpn DC 20460
"Jgyvw.epa.gov/owm
-*•- " -»^JJ •^ijfet ;
June 2000
fcj
Evaluation of the National'Investment
. -^fa isr *-— -r^—ifer
~*-irrMurn$ipal wastewater Treatment
Executive Summary
.-J».
*
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Dedication
This effort to document the water quality benefits associated with the federal
funding provided through the Construction Grants Program and Clean Water
State Revolving Fund (SRF) Program to help plan, design and construct publicly
owned treatment works (POTWs) was initiated at the request of Michael J.
Qtiigley while he served as Director of the Office of Municipal Pollution Control.
It is dedicated to the many hardworking and conscientious individuals—
including the program advocates and critics alike—who help manage, direct
(or in some cases redirect), and implement the Construction Grants and SRF
Programs, which are among the Nation's largest public works programs, in a
highly professional and effective manner. They include many EPA and state
program managers and staff and local wastewater authority managers and staff,
as well as the many highly qualified consultants and contractors who help the
local authorities conduct the necessary studies, develop the required facilities
plans and project design documents, and construct and operate the treatment
facilities that were established or upgraded with funding from these highly
successful public works programs.
The document could not have been written without the extensive water
quality monitoring efforts across the country undertaken by a legion of highly
qualified field staff and researchers for many local authorities, state and federal
agencies, and colleges and universities. Their efforts produced the extensive water
quality data available in the STORET system and local reports, as well as the
water quality models and local assessments that served as the basis for the analyses
undertaken and reported on in this document.
On The Cover
For four decades beginning in the 1920s the Lower Willamette River near Portland, Oregon, was considered
one of the most polluted urban-industrial rivers in the United States. In 1927 the Portland City Club
declared the Willamette River "ugly and filthy...with intolerable conditions." During the 1950s the Willamette
River was described as the "filthiest waterway in the Northwest and one of the most polluted in the
Nation." In 1967 the Izaak Walton League described the river as a "stinking slimy mess, a menace to
public health, aesthetically offensive and a biological cesspool."
Three decades after enactment of strict water pollution control regulations by the state of Oregon in the
late 1960s and the federal Clean Water Act in 1972, the remarkable improvements in water quality and
the ecological health of the river now provide important recreational and commercial benefits to the
citizens of the Willamette valley. Salmon and steelhead fisheries, once blocked by dams without fish
ladders and constrained by low dissolved oxygen conditions, are now sustained by migratory populations
that can safely reach upriver spawning grounds. The local economies of major cities on the Willamette
River are thriving, and upscale developments are attracted to riverfront locations by the aesthetics of a
clean river that was once considered noxious with an unsightly riverfront. Although the gross water pollution
problems of the first half of the 20th century have been eliminated, nutrient enrichment, sediment loading,
and the lingering presence of toxic chemicals in the river, sediment bed, and biota are ecological problems
that remain. Hopefully, they will be addressed in the early decades of the 21st century.
-------
A River Reborn
"Time has been good to the Potomac River—at least the
last 25 years have been . . . . A generation ago (1960s and
1970), when we had gone to the Potomac for thrills, the river
was ugly and almost frightening in its decay. The water was an
opaque red-brown sludge, smelly and foaming with unknown
chemical pollutants. The shore was littered with the rotting
carcasses of carp and with slime-covered tires, cans, glass and
other filth.
But as we sat talking this time, the water was clear—really
clear—as though we were in the countryside far from a big city.
We could see right to the sandy bottom. The shoreline was free
of debris, and the air smelledfresh.
Best of all were the birds. Mallards swooped overhead,
heading toward the water. Despite the season, some songbirds
still darted through the trees. And far out in the channel, close
to Virginia, a huge flock of birds circled round and round a
cluster of rocks. They seemed to be feeding out there (on what
type of freshwater creature?), and the sun glistened off their
wings....
Who are the stewards of the Potomac? Who is responsible
for the amazing rebirth of a beautiful river? To all, I extend a
hearty thanks..."
—Letter to the editor of The Washington Post,
January 15, 1995 (Chase, 1995)
-------
-------
Progress in Water Quality:
An Evaluation of the National Investment in Municipal Waste-water Treatment
Executive Summary
The existence of serious water
pollution problems in the United
States, first recognized during the 1920s
and 1930s and increasingly well documented
during the 1940s through 1960s, led to the rec-
ognition that the practice of discharging raw
sewage and the use of only primary treatment
in publicly owned treatment works (POTWs)
were generally inadequate technologies for
wastewater disposal.
Excessive loading of organic
matter, nutrients, sediment,
pathogens, and other pollutants
into surface waters, combined
with natural hydrologic (low-
flow) conditions, frequently ac-
counted for incidences of dis-
solved oxygen (DO) depletion,
fish kills, nuisance algal blooms,
and bacterial contamination in
rivers, lakes, and estuaries.
Many of the United States' most
famous water bodies, including
Lake Erie, New York Harbor,
and the Hudson, Upper Mississippi, Potomac,
Chattahoochee, Delaware, and Ohio rivers fell
victim to these symptoms.
In 1948 the 80th Congress encapsulated its frus-
tration with the situation when it declared that
"... The pollution of our water resources by
domestic and industrial wastes has become
an increasingly serious problem for the rapid
growth of our cities and industries. ... Pol-
luted waters menace the public health through
the contamination of water and food sup-
plies, destroy fish and game life, and rob us
of other benefits of our natural resources."
- Senate Report No. 462, 1948
For the first half of
the 20th century,
pollution //i the
Nation's urban
waterways resulted in
frequent occurrences
of low dissolved
oxygen, fish kills,
algal blooms,
and bacterial
contamination.
An Increased Federal
Policy Role in the Control
of Water Pollution
National policy for water pollution control has
been legislated primarily in the Federal "Water
Pollution Control Act. First passed in 1948, the
act has been amended numerous times (in 1956,
1961,1965,1966,1970,1972,1977,1981 and
1987) to gradually expand the
authority of the federal govern-
ment in regulating pollutant
discharges from point sources
to surface waters. Until enact-
ment of the 1972 (PL 92-500)
and more recent amendments,
now known as the Clean Wa-
ter Act (CWA), the primary au-
thority and responsibility for
water pollution control was at
the state level.
Unfortunately, there was a great
diversity among the states in
terms of ability and willingness
to pay the costs of building and upgrading
POTWs and to enforce pollution control laws.
Lack of local water quality standards, monitor-
ing data, and penalties for violators exacerbated
the situation. Despite 49 joint state-federal en-
forcement conferences that were convened af-
ter the 1965 Amendments to abate critical water
pollution problems, national progress in im-
proving water quality was hindered, in part,
because unless a state formally requested inter-
vention by the federal government, federal au-
thority for regulating discharges was restricted
to interstate and coastal waters.
Public awareness of nationwide water pollution
problems served as a political catalyst to shift
increased authority and responsibility for the
regulation of water pollution control from the
The 1972 CWA
shifted primary
authority for
water pollution
control from
the states to
the federal
government.
-------
From 1970 to 1995, USEPA distributed $61.1 billion
in grants for POTW upgrades to secondary treatment or
greater and, since 1988, over $16.1 billion in support
for state revolving loan funds for a wide range
of water quality improvement projects.
states to the federal government. Establishment
of a national policy requiring secondary treatment
of municipal wastewater as the minimum accept-
able technology supplemented by more stringent
water quality-based effluent controls on a site-spe-
cific, as-needed basis was a key provision of the
1972 act. This mandate, coupled with an in-
crease in funding assistance to municipalities
through the Construction Grants Program, led
to a dramatic increase in the number of POTWs
with secondary and advanced treatment capa-
bilities. Congress assumed that these actions
would direcdy support the long-term goal of
the CWA, the national attainment of "fishable
and swimmable" waters.
Figure 1
Annual funding provided by USEPA's Construction Grants
and CWSRF Programs to local municipalities for improve-
ments in water pollution control infrastructure from 1970 to
1999. Costs reported in current year dollars. (Data from
USEPA GICS database and CWSRF Program.)
Construction Grants
CWSRF
i i i i i i i i i i i i i i i i i i
1970
1995
2000
Year
The National Investment In
Municipal Wastewater
Treatment
A total of $61.1 billion ($96.5 billion as con-
stant 1995 dollars) was distributed to munici-
palities through USEPA's Construction Grants
Program in the 25-year period from 1970 to
1995 in support of the CWA's municipal waste-
water treatment program (Figure 1). An addi-
tional $16.1 billion (capitalization) was also dis-
tributed to the states through the Clean Water
State Revolving Fund (CWSRF) Program from
1988 through 1999. Including the state contri-
butions and loan repayments, the CWSRF loan
program assets have grown to over $30 billion
since 1988 and are funding about $3 billion in
water quality projects each year.
In terms of promoting the minimum accept-
able technology-based standard of secondary
treatment nationwide, this investment was an
outstanding success. By 1996 the number of
POTWs offering less than secondary treatment
dwindled to less than 200 (down from 2,435 in
1968 and 4,278 in 1978). Correspondingly,
there was a dramatic increase in the number of
facilities offering secondary treatment or greater
(from 10,052 facilities in 1968 to 13,816 facili-
ties in 1996).
; In 1968, 72 percent of the
Nation's POTWs were providing
secondary treatment and less than
1 percent were providing greater
than secondary treatment (out of
14,051 facilities). By 1996, 59
percent of the Nation's POTWs were
providing secondary treatment and
27 percent were providing greater
than secondary treatment (out of
16,024 facilities).
Executive Summary
-------
The number of people served by POTWs
with secondary or greater levels of
wastewater treatment almost doubled
between 1968 and 1996!
The success of these national investments is also
demonstrated by the increase in the number of
people served by POTWs, which shifted dra-
matically between 1968 (before-CWA) and
1996 (after-CWA), as shown in Figure 2. The
story told in Figure 2 is summarized below.
• The overall number of people served by
POTWs increased from 140.1 million in
1968 to 189.7million in 1996(a 35
percent increase).
• The number of people relying on POTWs
with less than secondary treatment
dropped rapidly after passage of the 1972
CWA. In 1968 about 39 percent (54.2
million) of the 140.1 million people
served by POTWs received less than
secondary treatment (raw and primary).
By 1996 this percentage was reduced to
about 9 percent (17.2 million) of the
189.7 million people served by POTWs.
This 9 percent includes approximately
5.1 million people currently served by
POTWs with CWA Section 301 (h)
waivers allowing the discharge of less
than secondary treated effluent to deep,
well-mixed ocean waters.
• While the number of people served by
POTWs with secondary treatment
remained fairly constant between 1968
and 1996 (a slight decrease of 3.7
million people or about 4 percent of the
population), the number of people
provided with greater than secondary
treatment increased significantly (from
0.3 million people in 1968 to 82.9
million people in 1996). Stated another
way, the U.S. population served by
POTWs with secondary or greater
treatment almost doubled between 1968
and 1996from 85.9 million people in
1968 to 164.8 million people in 1996!
-—————-—™-™«_™ra«™»«_. Figure 2
Population served by POTWs in 1968 (before the
CWA) and in 1996 (after the CWA) by treatment type.
(Data from U.S. Public Health Service municipal
wastewater inventories; USEPA Clean Water Needs
Surveys; USDOI, 1970; USEPA, 1997.)
Raw • < Secondary • Secondary D > Secondary D No Discharge:
Before the CWA (1 968)
After the CWA (1 996)
Raw discharges were eliminated by 1996.
p
Data for the "no-discharge" category were unavailable for 1968.
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
-------
Until now, no national-scale evaluation
of the effectiveness of the CWA's
technology- and water quality-based control
policies has been accomplished.
Was the Public's Investment In POTWs Worth It?
Questions concerning the environmental ben-
efits, as well as the cost-effectiveness, of the na-
tional investment in municipal wastewater treat-
ment have been raised by Congress and by spe-
cial interest, environmental, and business ad-
vocacy groups. In the 25 years after the enact-
ment of the CWA, studies have attempted to
evaluate progress in achieving the goals of the
CWA by documenting (a) administrative ac-
tions (e.g., numbers of discharge permits and
enforcement actions) and programmatic evalu-
ations (see Adler et al., 1993); (b) trends in na-
tional wastewater infrastructure (e.g., popula-
tion served by secondary or greater treatment
levels, effluent loading rates); (c) state and na-
tional inventories of waterways meeting desig-
nated uses (e.g., 305(b) reports); and (d) changes
in water quality following wastewater treatment
plant upgrades for specific waterways.
Evaluations of water quality conditions in the
United States include a pre-CWA national water
quality analysis of conditions from the 1940s
through the 1960s (Wolman, 1971; USEPA,
1974) and post-CWA assessments of the national
effectiveness of the 1972 CWA (e.g., Smith et
al., 1987a, 1987b). Assessments of local (Isaac,
1991; GAO, 1986), regional (Patrick etal., 1992),
and national water quality conditions (Smith et
al., 1992) have demonstrated improvements in
some water quality constituents following up-
grades to secondary or greater levels of wastewa-
ter treatment at municipal facilities.
There is, however, no study that has attempted
a national-scale comprehensive evaluation of the
effectiveness of the CWA's technology- and wa-
ter quality-based effluent control policies in
achieving the "fishable and swimmable" goals
of the act (Mearns, 1995).
STUDY OVERVIEW: The "Three-Legged Stool" Approach
This study takes a unique,
three-pronged approach for an-
swering the prima facie ques-
tion—Has the Clean Water Act's
regulation of wastewater treat-
ment processes at POTWs been
a success? Or posed more di-
rectly, How have the Nations
water quality conditions changed
since implementation of the
1972 CWA's mandate for sec-
ondary treatment as the mini-
mum acceptable technology for
POTWs?
This study takes a
unique three-pronged
approach to evaluate
nationwide progress
in water quality
conditions since
the enactment of
the 1972 CWA.
The three-pronged approach
described below (and presented
in the companion document,
USEPA, 2000) was developed
so that each study phase could
provide cumulative support
regarding the success, or failure,
of the CWA-mandated POTW
upgrades to secondary and
greater than secondary treat-
ment. Using the analogy of a
three-legged stool, the study
authors believed that each leg
must contribute support to the
premise of CWA success. If one
or more legs fail in this objec-
tive, the stool will be unable to
"stand up."
Executive Summary
-------
The First Leg: An
examination of BQD
loadings before and
after the CWA
As increasing numbers of people hooked into
more and upgraded POTWs, there was a corre-
sponding rise in influent BOD1 loading nation-
wide to these facilities. Figure 3 presents the
amount of influent BOD loading to "less than
secondary," secondary, and "greater than second-
ary" facilities for 1968 and 1996 (years repre-
senting before and after the CWA). BOD
loadings are shown both as BOD5 (carbona-
ceous BOD, i.e., oxygen demand from the de-
composition of organic carbon) as well as BODy
(ultimate BOD, which includes nitrogenous
BOD, i.e., oxygen demand from the decom-
position of ammonia and organic nitrogen, in
addition to carbonaceous BOD).
As shown, total influent loading of BOD in-
creased by about 35 percent, from 18,814 to
25,476 metric tons per day. Similarly, total in-
fluent loading of BODy increased by about 35
percent, from 34,693 to 46,979 metric tons per
day. Fortunately, this situation was counteracted
by the CWA wastewater treatment mandates,
which resulted in rising BOD removal efficien-
cies (Figure 3).
In 1968 the national aggregate removal efficien-
cies stood at about 63 percent and 39 percent for
BOD5andBODu> respectively. By 1996national
aggregate removal efficiencies had risen to nearly
85percent and 65percent, respectively!
BOD, or" biochemical oxygen demand" is a
measure of the oxygen-consuming organic
matter and ammonia-nitrogen in wastewater.
The higher the BOD loading, the greater the
depletion of oxygen in the waterway.
The amount of BOD5 and BODu discharged
from POTWs to the Nation's waterways
declined by about 45 percent and 23 percent,
respectively, after the 1972 CWA, despite a 35
percent increase in influent loadings!
' Figure 3
Influent and effluent loading of BOD to and from POTWs
in 1968 (before the CWA) and in 1996 (after the CWA)
by treatment type and associated BOD aggregate
removal efficiencies. (Data from U.S. Public Health
Service municipal wastewater inventories; USEPA Clean
Water Needs Surveys; USDOI, 1970; USEPA, 1997.)
\ < Secondary H Secondary D > Secondary
MM
I
1
t
D)
_C
IB
3
Q
O
m
x^V* X"^*
Before the After the Before the After the
CWA (1968) CWA (1996) CWA (1968) CWA (1996)
Consequently, the net result was decreasing lev-
els of effluent BOD loading to the Nation's wa-
terways (Figure 3). In 1968 the total effluent
loadings for BOD5 and BODy stood at about
6,932 and 21,281 metric tons per day, respec-
tively. By 1996 these amounts had dropped to
3,812 metric tons per day for BOD5 (a 45 per-
cent decline) and 16,325 metric tons per day
for BODy (a 23 percent decline), despite a cor-
responding 35 percent increase in influent BOD
loadings! Since many POTWs operate at even
higher BOD removal efficiencies, these design-
based effluent load reductions are understated,
compared to actual data reported in the Permit
Compliance System (PCS), which may vary
somewhat from year to year.
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
-------
Without continued improvements in wastewater
treatment infrastructure, future population growth
vv/7/ erode away many of the CWA achievements in
effluent loading reduction.
Figure 4
Projections of design-based, national effluent BOD,, loadings
through 2025 using middle-level U.S. population projections.
(Population projection data from U.S. Census, 1996.)
Assumptions:
Influent flow is a constant 165 gallon/capita-day1 with a BODU of 396.5
Projection Results:
Population served (millions)
Percent of total population
Design removal efficiency (BQDJ
Effluent BODU (metric tons/day)
1968
140.1
71%
39%
21,280
1972
141.7
69%
41%
20,831
1978
155.2
70%
52%
19,147
1996
189.7
72%
65%
16,325
mg/L
2016
275.0
88%
71%
19,606
2025
295.0
88%
71%
21,090
BU,UUU-
70,000-
"3; 60,000-
S 50,000-
1
•§• 40.000-
o>
1
o 30,000 -
8 20,000 -
10,000-
n .
• Influent BODu
• Effluent BODu
O Removal Efficiency
O
o
•pggjnE^P^
°^^ '/
„#/
" ~ °
0
o tf •
•"
III
I
O
-i
-I
-1
/
o
i
....
,
BODu Remova
3 O 0 C
- CO U> t
Efficiency (%,
3 O C
t CO C
ZU
-10
Year
165 gal/capita-day is based on the mean of population served and wastewater flow
data in the Clean Water Needs Surveys for 1978 through 1986 and accounts for
residential, commercial, industrial, stormwater, and infiltration and inflow compo-
nents.
Based on middle-level
population
projections, effluent
loading rates of
BODU in 2016 would
be similar to loading
rates experienced in
the mid-1970s, only a
few years after the
CWA!
The dynamic
relationship be-
tween influent
BOD loading,
BOD design re-
moval efficien-
cy, and effluent
BOD loading creates an important model for
planning new investments in wastewater treat-
ment infrastructure (Figure 4). Based on the data
reported in the 1996 Clean Water Needs Sur-
vey Report to Congress (USEPA, 1997), the
overall design BOD removal efficiency is likely
to increase somewhat because there is an appar-
ent trend toward a higher proportion of ad-
vanced (greater than secondary) POTWs. In die
next 20 years, however, the proportion of the
U.S. population served by POTWs is also likely
to increase as the urban population of the na-
tion increases.
Using the assumptions listed in Figure 4, and
using middle-level population growth projec-
tions from the Census Bureau (U.S. Census,
1996), it was estimated that by 2016 nearly 275
million people will be served by POTWs that
discharge to surface waters. Assuming a 165 gal/
capita-day influent flow and 396.5 mg/L con-
centration of influent BODu; this growth
(1996-2016) would result in a 45 percent in-
crease in influent BODy loading to POTWs
(68,030 metric tons per day) and a 20 percent
increase in effluent BODy loading to surface
waters (19,606 metric tons per day). These pro-
jected 2016 effluent BODy loadings are similar
to levels that existed in the mid-1970s, only a few
years after the CWA! Projecting further into the
future, effluent BODu loadings in 2025 (21,090
metric tons per day) would be similar to load-
ing rates experienced in 1968 (21,280 metric
tons per day), when they had reached a historic
maximum
level!
Executive Summary
-------
Future water quality management strategies will
need to consider integrated point and nonpofnt
source controls since POTWs account for only 21
percent of the total BOD5 loadings nationwide.
These types of projections underscore the im-
portance of the need to continually invest in
improvements to wastewater treatment infra-
structure in order to maintain and improve pol-
lutant removal efficiencies. Without these im-
provements, many of todays achievements in wa-
ter pollution control will be overwhelmed by
tomorrow's demand from urban population
growth. A recent report by the "Water Infrastruc-
ture Network (WIN, 2000) also documents the
risk of reversing the environmental gains of the
last three decades.
Although POTWs are often the dominant
source of BOD effluent loading in major urban
areas, other sources affect waterways on a na-
tional scale. To put POTW effluent loading in
perspective, USEPA's National Water Pollution
Control Assessment Model (NWPCAM) and
input data from USEPA's Permit Compliance
System (PCS) and the Clean Water Needs Sur-
vey (CWNS) were used to examine current
BOD5 loading (ca. 1995) for several key point
and nonpoint sources (Bondelid et al., 1999).
From a national perspective, it was found that
currently (ca. 1995) POTWBOD5 loadings ac-
count for only about 38 percent of total point
source loadings and only 21 percent of total
loadings (point and nonpoint). Industrial fa-
cilities (major and minor) currently account for
about 62 percent of total point source BOD
loadings and 34 percent of total BOD5 load-
ings. Clearly, continued improvement in the
water quality conditions of the Nation's water-
ways will require an integrated strategy to ad-
dress all pollutant sources, including both point
and nonpoint sources.
The first leg of the three-legged stool approach
focused on the Nation's investment in building
and upgrading POTWs to achieve at least sec-
ondary treatment. Based on this historical BOD
——. Figure 5
Percent changes in population served, influent BOD loading,
and effluent BOD5 and BODy loading before and after the
1972 CWA (1968 to 1996). (Data from U.S. Public Health
Service municipal wastewater inventories; USEPA Clean
Water Needs Surveys; USDOI, 1970; USEPA, 1997.)
^
1 25-
5 ^°
1
•a
c
B fl-
ff
1
tn
&
a -?1;
o
•£
a>
u
h.
o
"• -50-
ropuiciiioii - , miiuen
Served Load
35% 35%
BOD5
and
BODu
t
Effluent
Load
-45%
BOD5
Effluent
Load
-23%
BODu
loading analysis, it is clear that the CWA's
mandate for secondary treatment as the
minimum acceptable treatment technol-
ogy, supplemented by more stringent wa-
ter quality-based effluent controls on a site-
specific basis, combined with financial as-
sistance from the Construction Grants and
CWSRP Programs, resulted in a dramatic
nationwide decrease in effluent loading of
BOD from POTWs into the Nations wa-
terways (see Figure 5).
The 45 percent nationwide reduction in
effluent BOD5 loading and the 23 percent
reduction in effluent BODjj loading was
achieved during a period when total popu-
lation served and influent loading of BOD
both increased by 35 percent!
Conclusion
of the first leg
of the stool
There was a dramatic
nationwide decrease in
BOD effluent loading
from POTWs after the
1972 CWA despite a
significant increase in
population served!
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
-------
A systematic, peer-
reviewed approach was
developed to identify water
quality station records that
encode the "signal" related
to the water quality
impact of point source
discharges from the "noise"
of millions of historical
records archived in
STORET.
The Second Leg: An
examination of "worst'
case" DO in waterways
below point sources before
and after the CWA
The second leg follows up on the first leg with
the question Has the CWA'spush to reduce BOD
loading resulted in improved water quality in the
Nation's waterways? And, if so, to what extent?
The key phrase in the question is "to what ex-
tent?" Earlier studies by Smith et al. (1987a,
1987b) and Knopman and Smith (1993) con-
clude that any improvements in DO conditions
in the Nation's waterways are detectable only
within relatively local spatial scales downstream
of wastewater discharges.
Because of the ecological significance of DO and
its well-known causal relationship with the de-
composition of organic carbon (car-
bonaceous BOD) and the decompo-
sition of organic nitrogen and ammo-
nia (nitrogenous BOD) from waste-
water discharges, historical DO
records provide an excellent environ-
mental indicator for characterizing
water quality responses to long-term
changes in wastewater loading. A con-
siderable amount of historical data is
archived, and readily accessible, in
STORET, USEPA's national water
quality database.
The inherent difficulty in evaluating
the effectiveness of reductions in point
source loading is the need to isolate
the water quality impact of discharges from the
impacts caused by other confounding factors
such as nonpoint sources, as well as the natural
influence of streamflow and water temperature.
In this assessment, a systematic, peer-reviewed
approach has been designed to identify water
quality station records that encode the "signal"
related to the water quality impact of point
source discharges from the overwhelming
"noise" of millions of historical records archived
in STORET.
With DO as the key water quality indicator, and
keeping in mind the need to evaluate the change
in the DO "signal" over time (before and after
CWA) as well as over different spatial scales (i.e.,
river reaches [which average 10 miles in length],
catalog units, and major river basins), the fol-
lowing "rules" for data analysis were used in a
six-step data mining process to create before-
and after-CWA data sets of "worst case" DO to
be used in an unbiased comparison analysis of
downstream water quality conditions. The
screening rules associated with each phase are
listed below:
Step 1—Data Selection Rules
• DO data were extracted only for
summer (July-September).
• Only surface DO data (within 2 meters
of the surface) were used.
Step 2—Data Aggregation Rules From a
Temporal Perspective
• 1961-1965 served as the "time-block" to
represent persistent dry weather before
the CWA, and 1986-1990 served as the
time-block to represent persistent dry
weather after the CWA. These time-
blocks were selected based on an
analysis of long-term mean summer
streamflow.
• DO data must come from a station in a
catalog unit that had at least 1 dry year
out of the 5 years in each before- and
after-CWA time-block.
Executive Summary
-------
Worst case historical DO data were
aggregated by three scafes of spatial
hydrologic units: reach, catalog unit,
and major river basin.
Step 3—Calculation of the Worst-case
DO Summary Statistic Rules
• For each water quality station, the 10th
percentile of the DO data distribution
from the before-CWA time period (July
through September, 1961-1965) and the
10th percentile of the DO data distribu-
tion from the after-CWA time period
(July through September, 1986-1990)
were used as the DO "worst-case"
statistic for the comparison analysis.
• A station must have a minimum of
eight DO measurements within each of
the 5-year time-blocks.
Step 4—Spatial Assessment Rules
• Only water quality stations on streams
and rivers affected by point sources were
included in the before- and after-CWA
comparison analysis. Stations affected
only by nonpoint sources were ex-
cluded. Out of 64,902 river reaches in
the contiguous United States, 12,476
are downstream of a point source. Also,
out of 2,111 catalog units, 1,666 have
river reaches that are downstream of a
point source.
Step 5—Data Aggregation Rules From a
Spatial Perspective
• For each data set and time-block, the
10th percentile value from each eligible
station was aggregated within the spatial
hydrologic unit. (Since the scales are
hierarchical, a stations summary
statistic was effectively assigned to a
reach and a catalog unit.) A summary
statistic was then calculated and as-
signed to the spatial unit for the
purpose of characterizing its worst-case
DO. If a spatial unit had only one
monitoring station within its borders
meeting the screening criteria, the 10th
percentile DO value from that station
simply served as the unit's worst-case
summary statistic. If, however, there
were two or more stations within a
spatial units borders, the 10th percen-
tile values for all the eligible stations
were averaged, and this value used to
characterize worst-case DO for the unit.
Step 6—Development of the Paired
Data Sets (at each spatial scale)
• To be eligible for the paired (before vs.
after) comparison analysis, a hydrologic
unit must have both a before-CWA and
an after-CWA summary statistic
assigned to it.
The comparative before- and after-CWA analy-
sis of worst-case DO data derived using the
screening criteria described above and aggregated
by three scales of spatial hydrologic units (reach,
catalog unit, and major river basin) yielded the
following results.
Only water quality
stations on streams
and rivers affected by
point sources were
included in the before-
and after-CWA
comparison analysis.
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
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The 311 evaluated reaches
represent a disproportionately
high amount of urban/industrial
population centers.
Reach Scale Analysis
• 69 percent of the reaches evaluated showed
improvements in worst-case DO after the
CWA (311 reaches [out of a possible
12,476 downstream of point sources]
survived the data screening process with
comparable before- and after-CWA DO
summary statistics. The number of
reaches available for the paired analysis
was limited by the historical data
archived for the 1961-1965 period).
• These 311 evaluated reaches represent
a disproportionately high amount of
urban/industrial population centers,
with approximately 13.7 million
people represented (7.2 percent of the
total population served by POTWs in
1996). As shown in Figure 6, the top 25
improving reaches saw their worst-case
DO concentrations increase by 4.1 to
7.2 mglLl
The number of evaluated reaches
characterized by worst-case DO below
5 mg/L was reduced from 167 to 97
(from 54 to 31 percent).
The number of evaluated reaches
characterized by worst-case DO above
5 mg/L increased from 144 to 214
(from 46 to 69 percent).
Key finding at the
reach scale: 69
percent of the paired
reaches showed
worst-case DO
improvements after
the CWA!
10
Executive Summary
-------
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inding at the
catalog unit scale: 68
percent of the paired
catalog units showed
worst-case DO
improvements after
the CWA!
Catalog Unit Scale Analysis
• 68 percent of the catalog units evaluated
showed improvements in worst-case DO
after the CWA (246 catalog units [out of
a possible 1,666 downstream of point
sources] survived the data screening
process with comparable before- and
after-CWA. DO summary statistics).
• The number of evaluated catalog units
characterized by worst-case DO below
5 mg/L was reduced from 115 to 65
(from 47 to 26 percent). The number of
evaluated catalog units characterized by
worst-case DO above 5 mg/L increased
from 131 to 181 (from 53 to 74 per-
cent).
As shown in Figure 7, 53 of the 167
improving catalog units (32 percent)
improved by 2 mg/L or more while only
10 of 79 degrading catalog units (13
percent) degraded by 2 mg/L or more.
These 246 evaluated catalog units
represent a disproportionately high
amount of urban/industrial population
centers (see Figure 8), with approxi-
mately 61.6 million people represented
(32.5 percent of the total population
served by POTWs in 1996).
Figure 7 —
Frequency distribution of the mean 10th percentile DO for 246 catalog units that
improved (n=167) and degraded (n=79) after the CWA. (Source: USEPA STORET.)
(n) = number of catalog units
0>
Q.
7to8 6to7 5to6 4to5 3to4 2to3 1to2 Oto1
(a)
Magnitude of Decrease in
Worst-Case DO (mg/L) after the CWA
Oto1 1to2 2to3 3to4 4to5 5to6 6to7 7to8
(b)
Magnitude of Increase in
Worst-Case DO (mg/L) after the CWA
12
Executive Summary
-------
OQ 3|!iueoj3d mot ueoi/u
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
13
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Statistical tests run on the 311 paired
reaches aggregated as a national whole
revealed significant improvement in DO.
Major River Basin Scale Analysis
• A total of 11 out of 18 major river
basins had sufficient reach-aggregated
worst-case DO data for a before- and
after-CWA comparison.
• Based on two statistical tests, 8 of these 11
major river basins can be characterized as
having statistically significant improve-
ment in worst-case DO levels after the
CWA! The three basins that did not
statistically improve under either test
also did not have statistically significant
degradation (Table 1).
When all the 311 paired (i.e., before vs.
after) reaches were aggregated and the
statistical tests run on the contiguous
states as a national whole, worst-case
DO also showed significant improve-
ment.
Key finding at the
hydrologic region scale:
8 of the 11 major river
basins with sufficient data
had statistically significant
improvement in worst-case
DO levels after the CWA!
Table 1: Statistical Significance of Trends in Mean 10th Percentile (Worst-Case) DO by Major River Basin
Before vs. After the CWA (1961-1965 vs. 1986-1990). (Source: I/SERA STORE!.)
No. of Paired
(before vs. after)
River Basin
All USA (01-18)
01 - New England Basin
02 - Middle Atlantic Basin
03 - South Atlantic-Gulf
04 - Great Lakes Basin
05 - Ohio River Basin
06 - Tennessee River Basin
07 - Upper Mississippi Basin
08 - Lower Mississippi Basin
09 - Souris-Red Rainy Basin
10 - Missouri River Basin
11 - Arkansas-Red — White Basin
12 -Texas-Gulf Basin
13 - Rio Grande Basin
14 - Upper Colorado River Basin
15 - Lower Colorado River Basin
16 - Great Basin
17 - Pacific Northwest Basin
18 - California Basin
Paired t-test: 95% confidence - 2-sided test
"Insufficient data for analysis
Reaches
311
1
17
61
26
66
19
48
25
2
10
7
2
0
1
0
2
17
7
Worst-
Kolmogorov Case DO
Worst- 1
Case DO B
Paired Smirnov (mg/L) (mg/L) g
t-test
Yes
*
Yes
Yes
Yes
Yes
Yes
Yes
No
*
No
No
*
*
*
*
*
Yes
Yes
Kolmogorov Smirnov test:
test
Yes
*
Yes
Yes
Yes
Yes
No
Yes
No
*
No
No
*
*
*
*
*
No
Yes
90% confidence,
1961-65
4.56
4.30
2.80
4.10
3.85
5.40
4.08
3.80
3.79
5.65
5.76
5.36
5.77
--
4.88
—
7.45
7.61
5.61
2-sided test
1986-90 B
,-™ — , — ,™— H
5.53 if
6.90 i
4.94 i
4.73 i
6.06 1
6.04 B
5.23 1
5.31 I
3.94 i
6.75 1
6.53 1
4.60 i
4.37 1
u
7.22 i
H
6.10 I
8.21 1
7.58 I
i
Executive Summary
-------
Closer examination of urban
The second leg of the three-legged stool ap-
proach focused on assessing the change in the
point source discharge/downstream worst-case
DO signal over progressively larger spatial scales.
The results of this analysis show that there were
significant after-CWA improvements in worst-
case summer DO conditions in two-thirds of
the hydrologic units at all three spatial data ag-
gregation scales, from the small subwatersheds
of Reach File Version 1 river reaches (mean
drainage area of 115 mi2) to the very large wa-
tersheds of major river basins (mean area of
434,759 mi2).
These results provide strong evidence that the
CWA's requirements for municipal wastewater
treatment using secondary treatment as the
minimum acceptable technology, supplemented
by more stringent water quality-based effluent
controls on a site-specific basis, yielded broad
as well as localized benefits!
waterways helps identify, quantify,
and document specific causes of
water quality improvements.
Conclusion of
the second leg
of the stool
There were significant
after-CWA improvements
in worst-case summer DO
conditions in two-thirds
of the hydrologic units at
all three spatial scales!
The Third Leg: Case
Study Assessments of
Water Quality
The national-scale evaluation of long-term
trends in water quality conditions associated
with the second leg of the three-legged stool
identified numerous waterways characterized
by substantial improvements in DO after the
CWA. The uniqueness of each waterway and
the activities surrounding it requires an inves-
tigation to go beyond STORET to identify,
quantify, and document in detail the specific
actions that have resulted in water quality im-
provements and associated benefits to water
resource users.
Nine urban waterways were selected for closer
examination of the factors that caused improve-
ment in local water quality and environmental
resources (Figure 9). Note that the case study
site selection was made prior to completion of
the DO trend analysis described in the second
study leg.
Most of the case study waterways were sites
of interstate enforcement cases from 1957 to
1972, were listed as potential waterways to con-
vene state-federal enforcement conferences in
1963, or were subjects of water quality evalua-
tion reports prepared for the National Com-
mission on Water Quality. Two sites (Ohio
River and tributaries to the Hudson-Raritan
estuary) were on a 1970 list of the top 10 most
polluted rivers. Yet, interestingly, these case
study waterways included none of the 25 river
reaches with the greatest before- versus after-
CWA improvements in DO found in the sec-
ond leg of this study (see Figure 6).
These case study waterways represent heavily ur-
banized areas with historically documented wa-
ter pollution problems. A variety of data sources,
including the scientific literature, USEPA's na-
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
15
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Figure 9 ———— —--
Location map of case study waterways and distribution chart of their before- and after-CWA mean 10th
percentile DO for case study RF1 reaches: 1961-1970 vs. 1986-1995. (Source: USEPA STORE!)
2. Hudson-Raritan
estuary
3. Delaware estuary
ftwillamette River |
4. Potomac estuary
,
| 8. Upper Mississippi River [ ' j 7. Ohio River
5. James estuary I
Before the CWA
After the CWA
234567
Case Study Waterway Number
tional water quality database, and federal, state,
and local agency reports, were used to character-
ize long-term trends in population, point source
effluent loading rates, ambient water quality, en-
vironmental resources, and recreational uses. Ad-
ditional information was obtained from validated
water quality models for the Delaware, Potomac,
and James estuaries and Upper Mississippi River
case studies to quantify die water quality improve-
ments achieved by upgrading municipal facili-
ties to secondary and greater levels of treatment
as mandated by die 1972 CWA.
16
Executive Summary
-------
Key findings from the nine case studies are high-
lighted below.
• In each of the case study urban areas,
significant investments were made in
expansions and upgrades to POTWs
with commensurate increases in popula-
tion served.
• Before the CWA, during the 10-year
period from 1961 to 1970, "worst-case"
DO levels fell in the range of 1 to
4 mg/L for most of the case study sites;
after the CWA, during the 10-year
period from 1986 to 1995, worst-case
DO levels improved to levels of almost
5 to 8 mg/L.
• Water quality improvements associated
with BOD5, suspended solids, coliform
bacteria, heavy metals, nutrients, and
algal biomass have been linked to
reductions in municipal and industrial
point source loads for many of the case
study waterways.
• Tremendous progress has been made in
improving water quality, restoring
valuable fisheries and other biological
resources, and creating extensive water-
based recreational opportunities (an-
gling, hunting, boating, bird-watching,
etc.) in all case study waterways.
The results of the third leg of the three-legged
stool approach revealed that the significant in-
vestments made in municipal wastewater treat-
ment resulted in dramatic improvements in re-
storing water quality and biological resources and
in supporting thriving water-based recreational
uses in all the case study areas.'
Although significant progress has been achieved
in eliminating noxious water pollution condi-
tions, remaining problems with nutrient enrich-
ment, sediment contamination, heavy metals,
and toxic organic chemicals continue to pose
threats to human health and aquatic organisms
for these case study waterways. Serious ecologi-
cal problems remain to be solved for many of the
Nation's waterways, including the sites of these
case studies.
Conclusion of
the third leg
of the stool
Tremendous progress
has been achieved in
improving water quality,
restoring valuable
biological resources,
and creating recre-
ational opportunities in
all the case study areas!
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
17
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Conclusion
The three-legged stool approach to answering
the question Has the Clean Water Act's regula-
tion ofwastewater treatment processes atPOTWs
been a success? was developed
so that each of the legs could
provide cumulative support
regarding the success or fail-
ure of the CWA-mandated
POTW upgrades to at least
secondary treatment. Exam-
ining the results of each of
the study legs, the conclu-
sion is overwhelming that
the stool does indeed "stand
Conclusion of
the three-legged
stool approach
up
At both broad and local
scales, the water pollution
control policy decisions
of the 1972 CWA have
achieved significant suc-
cesses nationwide in terms
of reduction of effluent
BOD from POTWs,
worst-case (summertime,
low-flow) DO improve-
ment in waterways, and overall water quality
improvements in urban case study areas.
Each leg of the stool
cumulatively and quantita-
tively supports the theory
that the 1972 CWA's regula-
tion of wastewater treat-
ment processes at POTWs
has been a significant
success!
long-term trends in signals for water quality
parameters other than DO (e.g., suspended
solids, nutrients, toxic chemicals, pathogens) to
develop new performance
measures to track the effec-
tiveness of watershed-based
point source and nonpoint
source controls.
As new monitoring data are
collected, it is crucial for the
success of future perfor-
mance measure evaluations
of pollution control policies
that the data be submitted,
with appropriate QA/QC
safeguards, to accessible
databases. If the millions
of records archived in
STORET had not been
readily accessible, it would
have been impossible to
conduct this national analy-
sis of DO changes over the
last quarter century.
Manu challenges "•.
remain. We must maintain
and enhance the progress alreadu
hi, ,\, Y J
leved in municipal wastewater
pollution control as well as address
other pollution sources and problems
in the Nation's waterways.
The data mining and statisti-
cal methodologies de-
signed for this study
can potentially be
used to detect
Importantly, this study
provides the first national-scale comprehensive
evaluation of the effectiveness of the CWA's
technology- and water quality-based effluent
control policies in achieving the "fishable and
swimmable" goals of the act. Population
growth and expansion of urban development,
however, threaten to erase these achievements
unless improvement in wastewater treatment
and pollution control continues.
With the newer watershed-based strategies
for managing pollutant loading from point
and nonpoint sources detailed in USEPA's
Clean Water Action Plan (USEPA, 1998),
the Nation's state-local-private partner-
ships will continue to work to attain the
original "fishable and swimmable" goals
of the 1972 CWA for all surface waters
of the United States.
18
Executive Summary
-------
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