A EPA
United States
Environmental Protection
Agency
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of
National Primary Drinking Water Regulations
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Office of Water (4607M)
EPA 810-R-16-008
October 2016
www. epa. gov/ safewater
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Table of Contents
Executive Summary ES-1
1. Introduction 1-1
2. Cost Savings 2-1
2.1 Magnitude of Possible MCL Increase 2-1
2.2 Relative Source Water Concentration 2-1
2.3 Co-Occurring Contaminants 2-2
2.4 Treatment Technology 2-2
2.4.1 Ion Exchange 2-3
2.4.2 Granular Activated Carbon 2-3
2.4.3 Packed Tower Aeration 2-4
2.4.4 Lime Softening 2-4
2.4.5 Reverse Osmosis and Electrodialysis 2-4
3. Contaminant Characteristics and Sources 3-1
3.1 Toxic Release Inventory Data 3-2
3.1.1 Alachlor 3-3
3.1.2 Barium and Barium Compounds 3-4
3.1.3 Beryllium and Beryllium Compounds 3-9
3.1.4 2.4-1) 3-13
3.1.5 Lindane 3-15
3.1.6 Picloram 3-17
3.1.7 1,1,1-Trichloroethane 3-19
3.1.8 1,2,4-Trichlorobenzene 3-22
3.2 Pesticide Usage Estimates 3-23
3.2.1 Alachlor 3-24
3.2.2 2.4-1) 3-26
3.2.3 Diquat 3-28
3.2.4 Lindane 3-30
3.2.5 Picloram 3-31
4. Contaminant Occurrence Data Sources 4-1
4.1 NAWQA 4-1
4.2 PDP 4-2
4.3 Contaminant Occurrence 4-3
4.3.1 Alachlor 4-3
4.3.2 Barium 4-5
4.3.3 Beryllium 4-6
4.3.4 1,1-Dichloroethylene 4-8
4.3.5 2.4-1) 4-9
4.3.6 Diquat 4-11
4.3.7 Lindane 4-12
4.3.8 Picloram 4-14
4.3.9 1,1,1-Trichloroethane 4-16
4.3.101,2,4-Trichlorobenzene 4-17
5. Conclusions 5-1
6. References 6-1
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Table of Exhibits
Exhibit 1-1. Current and Possible MCLG Values 1-2
Exhibit 2-1. Possible MCL Increase 2-1
Exhibit 2-2. Summary of Treatment Technologies 2-2
Exhibit 3-1. Potential Sources of the Contaminants 3-1
Exhibit 3-2. Reported Disposal or Release of Alachlor (2013; pounds) 3-3
Exhibit 3-3. Reported Disposal or Release of Alachlor (2013; pounds) 3-4
Exhibit 3-4. Reported Disposal or Release of Barium (2013; pounds) 3-5
Exhibit 3-5. Reported Disposal or Release of Barium (2013; pounds) 3-6
Exhibit 3-6. Reported Disposal or Release of Barium Compounds (2013; pounds) 3-7
Exhibit 3-7. Reported Disposal or Release of Barium Compounds (2013; pounds) 3-9
Exhibit 3-8. Reported Disposal or Release of Beryllium (2013; pounds) 3-10
Exhibit 3-9. Reported Disposal or Release of Beryllium (2013; pounds) 3-11
Exhibit 3-10. Reported Disposal or Release of Beryllium Compounds (2013; pounds) 3-12
Exhibit 3-11. Reported Disposal or Release of Beryllium Compounds (2013; pounds) 3-13
Exhibit 3-12. Reported Disposal or Release of 2,4-D (2013; pounds) 3-14
Exhibit 3-13. Reported Disposal or Release of 2,4-D Compounds (2013; pounds) 3-15
Exhibit 3-14. Reported Disposal or Release of Lindane (2013; pounds) 3-16
Exhibit 3-15. Reported Disposal or Release of Lindane (2013) 3-17
Exhibit 3-16. Reported Disposal or Release of Picloram (2013; pounds) 3-18
Exhibit 3-17. Reported Disposal or Release of Picloram (2013; pounds) 3-19
Exhibit 3-18. Reported Disposal or Release of 1,1,1-Trichloroethane (2013; pounds) 3-20
Exhibit 3-19. Reported Disposal or Release of 1,1,1-Trichloroethane (2013; pounds) 3-21
Exhibit 3-20. Reported Disposal or Release of 1,2,4-Trichlorobenzene (2013; pounds) 3-22
Exhibit 3-21. Reported Disposal or Release of 1,2,4-Trichlorobenzene (2013; pounds) 3-23
Exhibit 3-22. Lower Bound Estimated Agricultural Use of Alachlor, 2012 3-24
Exhibit 3-23. Upper Bound Estimated Agricultural Use of Alachlor, 2012 3-25
Exhibit 3-24. Lower Bound Estimated Agricultural Use of 2,4-D, 2012 3-26
Exhibit 3-25. Upper Bound Estimated Agricultural Use of 2,4-D, 2012 3-27
Exhibit 3-26. Lower Bound Estimated Agricultural Use of Diquat, 2012 3-28
Exhibit 3-27. Upper Bound Estimated Agricultural Use of Diquat, 2012 3-29
Exhibit 3-28. Lower and Upper Bound Estimated Agricultural Use of Lindane, 2012 3-30
Exhibit 3-29. Lower Bound Estimated Agricultural Use of Picloram, 2012 3-31
Exhibit 3-30. Upper Bound Estimated Agricultural Use of Picloram, 2012 3-32
Exhibit 4-1. NAWQA Study Units 4-2
Exhibit 4-2. Summary of Alachlor Occurrence in NAWQA - Number and Percent of Locations
by Location Type 4-4
Exhibit 4-3. NAWQA Occurrence Data for Alachlor Based on Maximum Sample Values 4-4
Exhibit 4-4. Summary of Alachlor Occurrence for Raw Water Samples in USDA Agricultural
Marketing Service Pesticide Data Program (2007 - 2013) 4-5
Exhibit 4-5. Summary of Barium Occurrence in NAWQA - Number and Percent of Locations by
Location Type 4-5
Exhibit 4-6. NAWQA Occurrence Data for Barium Based on Maximum Sample Values 4-6
Exhibit 4-7. Summary of Beryllium Occurrence in NAWQA - Number and Percent of Locations
by Location Type 4-7
Exhibit 4-8. NAWQA Occurrence Data for Beryllium Based on Maximum Sample Values 4-7
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 4-9. Summary of 1,1-Dichloroethylene Occurrence in NAWQA - Number and Percent
of Locations by Location Type 4-8
Exhibit 4-10. Plot of 1-1-Dichloroethylene NAWQA Occurrence Data 4-9
Exhibit 4-11. Summary of 2,4-D Occurrence in NAWQA - Number and Percent of Locations by
Location Type 4-10
Exhibit 4-12. Plot of 2,4-D NAWQA Occurrence Data 4-10
Exhibit 4-13. Summary of 2,4-D Occurrence for Raw Water Samples in USD A Agricultural
Marketing Service Pesticide Data Program (2007 - 2013) 4-11
Exhibit 4-14. Crop and Noncrop Diquat Application for California in 2012 4-11
Exhibit 4-15. National Pesticide Use for Crops (2000 to 2009, pounds) 4-12
Exhibit 4-16. Summary of Lindane Occurrence in NAWQA - Number and Percent of Locations
by Location Type 4-12
Exhibit 4-17. Plot of Lindane NAWQA Occurrence Data 4-13
Exhibit 4-18. Summary of Lindane Occurrence for Raw Water Samples in USD A Agricultural
Marketing Service Pesticide Data Program (2007 - 2013) 4-13
Exhibit 4-19. Summary of Picloram Occurrence in NAWQA - Number and Percent of Locations
by Location Type 4-14
Exhibit 4-20. Plot of Picloram NAWQA Occurrence Data 4-15
Exhibit 4-21. Summary of Picloram Occurrence for Raw Water Samples in USDA Agricultural
Marketing Service Pesticide Data Program (2007 - 2013) 4-16
Exhibit 4-22. Summary of 1,1,1-Trichloroethane Occurrence in NAWQA - Number and Percent
of Locations by Location Type 4-16
Exhibit 4-23. Plot of 1,1,1-Trichloroethane NAWQA Occurrence Data 4-17
Exhibit 4-24. Summary of 1,2,4-Trichlorobenzene Occurrence in NAWQA - Number and
Percent of Locations by Location Type 4-18
Exhibit 4-25. Plot of 1,2,4-Trichlorobenzene NAWQA Occurrence Data 4-18
Exhibit 5-1. Summary of Potential for Cost Savings Based on Source Water Concentrations... 5-1
Exhibit 5-2. Summary of Potential for Cost Savings Based on Treatment Technology 5-2
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Abbreviations and Acronyms
AT SDR
Agency for Toxic Substances & Disease Registry
BAT
best available technology
CF
coagulation filtration
DBP
disinfection byproduct
EDR
electrodialysis reversal
EPA
U.S. Environmental Protection Agency
GAC
granular activated carbon
IX
ion exchange
LS
lime softening
MCL
maximum contaminant level
MCLG
maximum contaminant level goal
MSBA
multi-stage bubbling aeration
NAICS
North American Industry Classification System
NAWQA
National Water Quality Assessment
NPDWR
National Primary Drinking Water Regulation
PAC
powdered activated carbon
PDP
U.S. Department of Agriculture Pesticide Data Program
POTW
publicly owned treatment works
POU
point-of-use
PTA
packed tower aeration
RO
reverse osmosis
SDWA
Safe Drinking Water Act
TRI
Toxics Release Inventory
USD A
U.S. Department of Agriculture
USGS
U.S. Geological Survey
iv
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Executive Summary
The U.S. Environmental Protection Agency (EPA or the Agency) has completed its third Six-
Year Review (Six-Year Review 3) of national primary drinking water regulations (NPDWRs).
The 1996 Safe Drinking Water Act (SDWA) Amendments require EPA to periodically review
existing NPDWRs. Section 1412(b)(9) of SDWA reads:
,..[t]he Administrator shall, not less often than every 6 years, review and revise,
as appropriate, each national primary drinking water regulation promulgated
under this subchapter. Any revision of a national primary drinking water
regulation shall be promulgated in accordance with this section, except that each
revision shall maintain, or provide for greater, protection of the health of persons.
The primary goal of the Six-Year Review process is to identify NPDWRs for possible regulatory
revision. Although the statute does not define when a revision is "appropriate," as a general
benchmark, EPA considered a possible revision to be "appropriate" if, at a minimum, it presents
a meaningful opportunity to:
• improve the level of public health protection, and/or
• achieve cost savings while maintaining or improving the level of public health protection.
For Six-Year Review 3, EPA obtained and evaluated new information that could affect a
NPDWR, including information on health effects (USEPA, 2016c), analytical feasibility
(USEPA, 2016b), and finished water occurrence (USEPA, 2016a). EPA identified new health
effects assessments that indicate the possibility to raise maximum contaminant level goal
(MCLG) values for a number of regulated contaminants. Consequently, EPA reviewed data on
contaminant occurrence in source water to determine if there is a meaningful opportunity to
achieve cost savings while maintaining or improving the level of public health protection. This
document describes this review.
Exhibit ES-1 shows the current MCLG values for contaminants for which new health effects
assessments indicate a possible MCLG that is higher than the MCLG in the NPDWR. The new
health effects information results in a wide range of possible MCLG increases. The lowest
relative increase is 2 times the current MCLG for both diquat and picloram. The highest relative
increase is 150 times the current MCLG for the possible MCLG for lindane.
The exhibit also shows the current maximum contaminant level (MCL) values, most of which
equal the MCLG values. The possible MCLG value for each contaminant is higher than the
corresponding current MCL value. Thus, a revision to the MCLG for a contaminant would affect
the MCL, which could reduce costs for drinking water systems that control the contaminant to
meet the MCL.
ES-1
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit ES-1. Current MCLG/MCL Values and Possible MCLG Values
Contaminant
Current MCLG/MCL
(mq/L)
Possible MCLG
(mq/L)
Alachlor1
0.0 (MCLG)
0.002 (MCL)
0.04
Barium1
2
6
Beryllium
0.004
0.01
1,1 -Dichloroethylene1
0.007
0.4
2,4-Dichlorophenoxyacetic acid (2,4-D)
0.07
2
Diquat1
0.02
0.04
Lindane (gamma-Hexachlorocyclohexane)1
0.0002
0.03
Picloram1
0.5
1
1,1,1 -T richloroethane1
0.2
14
1,2,4-T richlorobenzene
0.07
0.7
Source: USEPA, 2016c
1. Although new health effects information indicated a possibility to increase MCLG during the first or second Six-Year
Review, EPA made a decision not to revise the NPDWR because the revision was a low priority.
The potential for and magnitude of cost savings related to MCL changes depend on four factors:
• The magnitude of increase in the MCL;
• The concentration of the contaminant in the source water, relative to the current MCL
and the possible MCLG;
• The presence of co-occurring contaminants treated with the same technology and the
relative importance to the design and operation of the treatment technology; and
• The specific treatment technology currently employed.
EPA's analysis of the potential for cost savings was constrained to readily available data. The
data available to characterize contaminant occurrence was especially limited because there is no
comprehensive dataset that characterizes source water quality for drinking water systems. Data
from the National Water Quality Assessment (NAWQA) program conducted by the U.S.
Geological Survey (USGS); and U.S. Department of Agriculture (USD A) Pesticide Data
Program (PDP) water monitoring survey provide useful insights into potential contaminant
occurrence in source water. However, these data are not based on random or representative
sampling events and, therefore, cannot be used directly to derive quantitative estimates of
national occurrence in drinking water sources.
Nevertheless, the available data indicate relatively infrequent contaminant occurrence in
potential source waters at the levels of interest. The NAWQA data, which provide the most
extensive coverage of potential source waters, indicate that only alachlor is found in
concentrations that exceed the possible MCLG. In particular, picloram is not found at levels
above either the current MCLG or the possible MCLG in either dataset. Diquat, which is not
included in these datasets, potentially occurs infrequently in source water given less frequent use
compared to the other pesticides in the table (alachlor, lindane and picloram) and that it tends to
dissipate quickly from surface water and be immobile in soils.
ES-2
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Without national estimates of contaminant occurrence in drinking water sources, EPA cannot
estimate how many systems currently treat for the contaminants listed in Exhibit ES-1. EPA also
does not have national data regarding the treatment technologies being utilized to control these
contaminants. Use of some technologies would result in higher operational cost savings from
reduced use; however, co-occurrence considerations for all of the Best Available Technologies
(BAT) could diminish the ability to alter treatment for possible higher MCLGs.
Despite the possibility for changes in MCLG values that range from 2 to 150 times higher than
current MCLs, the available occurrence data for potential drinking water sources indicate
relatively low contaminant occurrence in the concentration ranges of interest. As a consequence,
EPA cannot conclude that there is a meaningful opportunity for system cost savings.
ES-3
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
1. Introduction
The U.S. Environmental Protection Agency (EPA or the Agency) has completed its third Six-
Year Review (Six-Year Review 3) of national primary drinking water regulations (NPDWRs).
The 1996 Safe Drinking Water Act (SDWA) Amendments require the Agency to periodically
review existing NPDWRs. Section 1412(b)(9) of SDWA reads:
,..[t]he Administrator shall, not less than every 6 years, review and revise, as
appropriate, each primary drinking water regulation promulgated under this title.
Any revision of a national primary drinking water regulation shall be promulgated
in accordance with this section, except that each revision shall maintain, or
provide for greater, protection of the health of persons.
The primary goal of the Six-Year Review process is to identify NPDWRs for possible regulatory
revision. Although the statute does not define when a revision is "appropriate," as a general
benchmark, EPA considered a possible revision to be "appropriate" if, at a minimum, it presents
a meaningful opportunity to:
• improve the level of public health protection, and/or
• achieve cost savings while maintaining or improving the level of public health protection.
For Six-Year Review 3, EPA implemented the protocol that it developed for the first Six-Year
Review (USEPA, 2003), including minor revisions developed during the second review process
(USEPA, 2009). EPA obtained and evaluated new information that could affect a NPDWR,
including information on health effects (USEPA, 2016c), analytical feasibility (USEPA, 2016b),
and finished water occurrence (USEPA, 2016a). EPA identified new health effects assessments
that indicate the possibility to raise maximum contaminant level goal (MCLG) values for a
number of regulated contaminants. An MCLG is a concentration at which there is no known
health risk. Consequently, EPA reviewed data on contaminant occurrence in source water to
determine whether there is a meaningful opportunity to achieve cost savings while maintaining
the level of public health protection. This document describes this review.
Exhibit 1-1 shows the current MCLG values for contaminants for which new health effects
assessments indicate a possible MCLG that is higher than the MCLG in the NPDWR. The new
health effects information results in a wide range of possible MCLG increases. The lowest
relative increase is 2 times the current MCLG for diquat and picloram. The highest relative
increase is 150 times the current MCLG for the possible MCLG for lindane.
Exhibit 1-1 also shows the current maximum contaminant level (MCL) values, most of which
equal current MCLG values. The MCL values are the regulatory standards that limit contaminant
concentrations in water distributed by public water systems. The possible MCLG value for each
contaminant is greater than the corresponding current MCL value. Thus, a revision to the MCLG
for each contaminant would need to be accompanied by an increase in the corresponding MCL.
Increasing the regulatory limit could result in reduced treatment costs for drinking water systems
that control the contaminant to meet the current MCL while providing the same level of health
protection.
1-1
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 1-1. Current and Possible MCLG Values
Contaminant
Current MCLG
(mq/L)
Current MCL
Possible MCLG
(mq/L)
Alachlor1
0
0.002
0.04
Barium1
2
2
6
Beryllium1
0.004
0.004
0.01
1,1 -Dichloroethylene1
0.007
0.007
0.4
2,4-Dichlorophenoxyacetic acid (2,4-
D)
.07
.07
2
Diquat1
0.02
0.02
0.04
Lindane (gamma-
Hexachlorocyclohexane)1
0.0002
0.0002
0.03
Picloram1
0.5
0.5
1
1,1,1 -T richloroethane1
0.2
0.2
14
1,2,4-T richlorobenzene
0.07
0.07
0.7
Source: USEPA, 2016c
1. Although new health effects information indicated a possibility to increase MCLG during the first or second Six-Year Review,
EPA made a decision not to revise the NPDWR because the revision was a low priority.
In making its recommendation to revise or take no action regarding an MCLG, EPA needs to
determine whether there is a meaningful opportunity for cost savings while maintaining the same
level of protection. This report provides the information EPA reviewed to make this
determination.
During the first and second Six-Year Review cycles, EPA made a recommendation not to revise
several NPDWRs for which an increase in MCLG was possible, including several under
consideration again during the current review. EPA's past recommendations were based on its
determination that the potential for cost savings was low. As a result, EPA classified the MCLG
revisions as a low priority activity for the Agency because of competing workload priorities,
administrative costs associated with rulemaking, and the burden on States and the regulated
community to implement any regulatory change that resulted.
This technical support document addresses the potential for cost savings, which depends on the
potential cost savings impact at the system level and the number of systems affected. Section 2
provides a discussion of the factors affecting the potential for cost savings for each contaminant
of interest. Section 3 discusses the sources of these contaminants and current usage of some of
the contaminants. Section 4 summarizes water quality data that is readily available to
characterize contaminant occurrence. Section 5 provides a summary of information regarding
whether possible changes to the MCLGs constitute a meaningful opportunity to reduce costs
while maintaining health protection. USEPA (2016a) provides occurrence analysis information
for other contaminants included in the Six-Year Review 3.
1-2
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
2. Cost Savings
MCLG revisions alone do not produce cost-savings. The potential for cost savings comes from
subsequent revisions to the MCL values, which could affect treatment activities at regulated
public water systems. The magnitude of these cost savings depend on four factors:
• The magnitude of increase in the MCL
• The concentration of the contaminant in the source water, relative to the current MCL
and the possible MCLG
• The presence of co-occurring contaminants treated with the same technology and the
relative importance to the design and operation of the treatment technology
• The specific treatment technology currently employed.
The following sections address each of these factors.
2.1 Magnitude of Possible MCL Increase
In general, the potential for cost savings increases as the magnitude of the MCL change
increases. A larger MCL increase has the potential to affect a greater number of systems and to
result in more substantial changes in treatment operations. Exhibit 2-1 presents the magnitude of
possible change for the contaminants of interest.
Exhibit 2-1. Possible MCL Increase
Contaminant
Multiple of Current MCL
Alachlor
20
Barium
3
Beryllium
2.5
1,1 -Dichloroethylene
57
2,4-D
29
Diquat
2
Lindane (gamma-Hexachlorocyclohexane)
150
Picloram
2
1,1,1 -T richloroethane
70
1,2,4-Trichlorobenzene
10
Based solely on multiples of the current MCLs, the potential for cost savings appears lower for
barium, beryllium, diquat, and picloram than for alachlor, 1,1-dichloroethylene, 1,1,1-
trichloroethane and 1,2,4-trichlorobenzene . Given the uncertainty in the possible MCLG range
for lindane, the potential ranges from low to high.
2.2 Relative Source Water Concentration
If an MCL increases, there are two potential scenarios that could result in treatment cost savings:
• Treatment is no longer required because the source water concentration is less than the
possible higher MCL
• Less treatment is required even though the source water concentration is greater than the
possible higher MCL.
2-1
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Occurrence Analysis for Potential Source Waters
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The potential cost savings under the first scenario are greater than under the second, because a
system could cease treatment for the contaminant altogether. There is no comprehensive
database of source water quality for public water systems. Therefore, EPA reviewed available
data on contaminant releases and ambient water quality to characterize source water occurrence.
Section 3 provides contaminant release data from EPA's Toxics Release Inventory (TRI) and
pesticide application rate estimates produced by the U.S. Geological Survey (USGS). Section 4
contains occurrence data summaries from two source water quality monitoring programs the
National Water Quality Assessment (NAWQA) program conducted by the USGS and the
Pesticide Data Program (PDP) conducted by the U.S. Department of Agriculture (USDA).
2.3 Co-Occurring Contaminants
The presence of co-occurring contaminants is a potential limiting factor on the cost savings that
can be achieved given an MCL increase. Co-occurring contaminants are relevant when the same
treatment process that removes the target contaminant also removes the co-occurring
contaminant(s). Potential cost savings depend on the relative importance of each contaminant to
the design and operation of the process. If the target contaminant controls treatment operation,
then there may be a greater opportunity for cost savings. On the other hand, if a co-occurring
contaminant controls treatment operation, then it may not be possible to adjust operations.
For example, a system with coagulation/filtration to remove turbidity, followed by granular
activated carbon (GAC) to remove lindane, could realize a cost savings as a result of an increase
in the lindane MCL if the GAC system can be adjusted without a significant effect on turbidity
removal. If, however, the GAC process also removes other regulated organic contaminants, the
operation may not be able to be adjusted despite a change in the lindane MCL.
2.4 Treatment Technology
Exhibit 2-2 summarizes the best available technologies (BAT) and small system compliance
technologies for each of the contaminants.
Exhibit 2-2. Summary of Treatment Technologies
Contaminant
Best Available Treatment
Small System Compliance
Technologies
Alachlor
GAC
GAC, POU GAC, PAC
Barium
IX, LS, RO, EDR
CF, IX, LS, RO, EDR, POU IX, POU RO
Beryllium
AA, CF, IX, LS, RO
AA, CF, IX, LS, RO, POU IX, POU RO
Diquat
GAC
GAC, POU GAC, PAC
1,1 -Dichloroethylene
PTA, GAC
PTA, GAC, MSBA, Aeration (diffused, tray,
shallow tray)
Lindane (gamma-
Hexachlorocyclohexane)
GAC
GAC, POU GAC, PAC
Picloram
GAC
GAC, POU GAC, PAC
1,1,1 -T richloroethane
PTA, GAC
PTA, GAC, MSBA, Aeration (diffused, tray,
shallow tray, spray)
2-2
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Contaminant
Best Available Treatment
Small System Compliance
Technologies
2,4-D
GAC
GAC, POU GAC, PAC
1,2,4-Trichlorobenzene
PTA, GAC
PTA, GAC, MSBA, Aeration (diffused, tray,
shallow tray)
AA = Activated Alumina; CF = Coagulation/Filtration; EDR = Electrodialysis; GAC = Granular Activated Carbon; IX = Ion
Exchange; LS = Lime Softening; MSBA = Multi Stage Bubble Aeration; PAC = Powdered Activated Carbon; POU = point-of-
use; PTA = Packed Tower Aeration; RO = Reverse Osmosis;
Sources: 40 CFR 141.61 and 141.62, USEPA 1998b.
One potential operational change that is highly dependent on the magnitude of the MCL increase
is the degree of blending used by a treatment system. Some systems treat only a portion of the
source water to a level well below the MCL and then blend the treated water with untreated
water, resulting in blended water with contaminant concentrations below the MCL. An MCL
increase could result in a system reducing the quantity of water being treated and increasing the
quantity of untreated water in its blending operation. This change could result in reduced
operating costs such as labor costs for operating the treatment system and, potentially, reduced
energy costs for pumping water through the treatment process.
The potential for cost savings (e.g., chemical use, energy, media replacement) vary by treatment
technology (i.e., some technologies, once in place, are more amenable to operational changes
than others). The following sections provide discussions of the factors affecting the potential cost
savings for each technology in Exhibit 2-2.
2.4.1 Ion Exchange
Increasing the MCL for a target contaminant in an ion exchange system could allow for greater
run times before regeneration or replacement of the ion exchange resin. This longer run length
would mean a reduction in regeneration chemical use, with associated cost savings, or a
reduction in the cost of replacement resin/media. Alternatively, by changing bed depth, a system
can reduce the quantity of resin or media present, with similar cost savings. Therefore, these cost
savings could be large relative to the total operating cost of the technology, particularly if the
magnitude of the MCL change is large.
Also, ion exchange systems are more likely than other systems to be operated for the removal of
a single contaminant. This circumstance is particularly true of systems with contaminant-specific
resins. Thus, co-occurring contaminants may be less of a concern for some systems using this
technology. Even when operated to remove multiple contaminants, this technology is amenable
to changes in the resin used. If the MCL for one contaminant increases such that it is no longer a
concern, the system can switch to a contaminant-specific resin (e.g., resin designed for arsenic
removal) that is more efficient for removal of a co-occurring contaminant, with potential cost
savings.
2.4.2 Granular Activated Carbon
Similar to ion exchange, with an increased MCL, granular activated carbon (GAC) systems may
be able to be adjusted to extend the run length before regeneration or replacement of the GAC
media or decrease the bed depth to reduce the GAC quantity. Cost savings could be large relative
2-3
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Occurrence Analysis for Potential Source Waters
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to the total operating cost of the technology, particularly if the magnitude of the MCL change is
large.
Unlike ion exchange, however, GAC removes a wide spectrum of organic and inorganic
compounds including disinfection byproduct (DBP) precursors, and is more likely to be used for
the removal of multiple contaminants. Thus, co-occurring contaminants may limit or eliminate
the potential for cost savings, depending on which contaminant(s) have the greatest influence on
GAC operation. Also, although all GAC media are not the same, there is less potential for a
change in GAC media to result in significant cost savings.
2.4.3 Packed Tower Aeration
An increased MCL could allow packed tower aeration (PTA) systems treating for 1,1-
dichloroethylene, 1,1,1-trichloroethane, or 1,2,4-trichlorobenzene to reduce the air-to-water ratio,
resulting in reduced energy cost for blowers. Blower energy costs, however, make up a small
portion of total operating costs. Thus, the cost savings could be small relative to the total
operating cost of the technology.
Also like GAC, PTA can remove a wide range of contaminants, specifically volatile
contaminants, and is more likely to be used for the removal of multiple contaminants. Thus, co-
occurring contaminants may eliminate the potential for cost savings or limit the savings to the
extent 1,1-dichloroethylene, 1,1,1-trichloroethane, or 1,2,4-trichlorobenzene treatment controls
the air-to-water ratio.
2.4.4 Lime Softening
An increased MCL may allow lime softening systems to reduce the dose of treatment chemicals
(coagulant or lime), resulting in reduced cost. Similar to oxidation, however, lime softening
systems also are typically installed for another primary purpose (e.g., solids and/or hardness
removal). The treatment of the target contaminant would likely be a secondary benefit of the
system. Cost savings would be limited to the extent that the MCL increase controls the coagulant
or lime dose. Although chemical costs make up a moderate portion of operating cost for this
technology, the ability to reduce these costs significantly would likely be small because of
treatment needs for other contaminants. It is unlikely systems would be able to cease lime
softening treatment, given the need to continue removal of solids and/or hardness.
2.4.5 Reverse Osmosis and Electrodialysis
These two technologies generally achieve a very high removal rate for a wide variety of
contaminants. Although some operational adjustments may be possible (e.g., changes in blending
ratios), these changes would not have a dramatic effect on operating costs unless there are no co-
occurring contaminants. These technologies are very likely to be used for removal of multiple
contaminants, thereby limiting the potential for cost savings due to an MCL change for one
contaminant.
2-4
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
3. Contaminant Characteristics and Sources
Toxic pollutants can be introduced to surface water through natural sources as well as human
activities. Exhibit 3-1 provides a brief summary of the uses and potential sources for the
contaminants of interest.
Exhibit 3-1. Potential Sources of the Contaminants
Contaminant
Sources of Potential
Release to the
Environment
Description/Uses
Environmental Fate and
Transport
Alachlor
Agricultural runoff
Herbicide used for weed control:
corn, soybeans, sorghum, peanuts,
and beans.
Low absorption to soil; soluble
and highly mobile in water;
leaches to ground water.
Barium
Industrial waste; drilling
waste ground application,
offshore drilling waste
water; copper smelting;
erosion of natural
deposits.
Naturally occurring metal; used in oil
and gas drilling mud, jet fuel,
pesticides, paint, bricks, ceramics,
glass, and rubber.
Leaching and erosion of natural
deposits into ground water;
atmospheric deposition;
precipitate out of aquatic media
as insoluble salt; adsorb to
suspended solids in surface
water; not mobile in soil systems.
Beryllium
Wastewater discharge
from industry and electric
utilities, deposition of
atmospheric beryllium,
and weathering of rocks
and soils.
Metal commonly converted into
alloys; used in making electrical and
electronic parts, construction
materials for machinery, molds for
plastics, automobiles, sports
equipment, vehicles, and dental
bridges.
Does not degrade in the
environment; carried to rivers by
deposition or land erosion; low
mobility in sediment.
1,1-
Dichloroethylene
Atmospheric emissions or
wastewater discharge
from manufacturing
plants.
Industrial chemical used in making
adhesives, synthetic fibers,
refrigerants, food packaging, and
coating resins.
Hydrophobic; highly volatile; if
spilled on land, may leach to
ground water.
2,4-D
Runoff from agricultural,
forest, aquatic, and
residential application.
Herbicide used for control of
broadleaf weeds, fruit & vegetable
crops, forestry, right-of-way, aquatic,
and residential applications.
Intermediately to very mobile in
soil; leaches to ground water;
Diquat
Agricultural runoff;
manufacturing
wastewater discharges.
Herbicide used to control plant
growth in aquatic environments and
as agricultural and residential
herbicide.
Permanently adsorbs to soil;
rapidly adheres to sediments
when released to water;
immobile.
Lindane (gamma-
Hexachlorocycloh
exane)
Agricultural runoff;
atmospheric emissions;
rain and snow deposition.
Insecticide used to treat a variety of
crop seeds until 2011.
Volatile; sorbs to soil, leaching to
ground water (soluble in water at
7 mg/L).
Picloram
Runoff from agricultural,
forest, and rights-of-way
application.
Herbicide used to control feed crop
pastures, nonfood crops (rights-of-
way), and in forestry.
Highly soluble and mobile in
water; leaches to ground water,
no degradation.
3-1
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Contaminant
Sources of Potential
Release to the
Environment
Description/Uses
Environmental Fate and
Transport
1,1,1-
Trichloroethane
Atmospheric emissions or
wastewater discharge
from manufacturing
plants, discharge or
leaching from landfills.
Industrial chemical used as a solvent
and in production of
hydrofluorocarbons.
Highly volatile; sorbs to soil, may
leach to ground water;
atmospheric deposition; moderate
solubility.
1,2,4-
Trichlorobenzene
Atmospheric emissions or
wastewater discharge
from manufacturing
plants, discharge or
leaching from landfills.
Industrial chemical used as a solvent,
a chemical intermediate (e.g., in dye
and pesticide production), a dielectric
fluid in transformers, a lubricant, and
in synthetic transformer oils.
Volatile; sorbs to soil, sediment
and suspended solids; may leach
to ground water
Source: USEPA, 1998a; ATSDR, 2002; ATSDR, 2007; USEPA, 2002; USEPA, 1995a; USEPA, 2006; USEPA, 1995b; USEPA,
2007; ATSDR, 2006, ATSDR, 2014, USEPA, 2005.
3.1 Toxic Release Inventory Data
EPA collected the most recently reported state level releases and disposal data for the pollutants
of concern from its Toxic Release Inventory (TRI). This data identifies states that are most likely
to have anthropogenic sources of the contaminants of interest that are reported to the TRI, which
excludes agricultural applications of pesticides. TRI does not have release or disposal data for
1,1-dichloroethane or diquat. The following table and map exhibits show the total number of
pounds of each pollutant of interest reportedly released or disposed of on-site to different media,
the total off-site disposal/releases, and a graphical representation of the total releases/disposal.
3-2
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
3.1.1 Alachlor
Alachlor releases occurred only in Iowa, Ohio, and Texas in 2013 (see Exhibit 3-2 and Exhibit
3-3). Most of the 32 pounds were released to air; 4 pounds were disposed off-site.
Exhibit 3-2. Reported Disposal or Release of Alachlor (2013; pounds)
Total Off-
On-site
On-site
site
Total On-
Surface
Under-
On-site
Other On-
Total On-site
Disposal
and Off-site
On-site
Water
ground
Landfill
site
Disposal or
or
Disposal or
State
Air1
Discharges2
Injection3
Disposal4
Releases5
Releases
Releases6
Releases
Iowa
15
1
0
0
0
16
4
20
Ohio
4
0
0
0
0
4
0
4
Texas
8
0
0
0
0
8
ND
8
Total
27
1
0
0
0
28
4
32
Source: USEPA, 2015
ND: no data reported
1. Includes fugitive and point source air releases. Fugitive emissions are all releases to air that are not released through a confined
air stream. Fugitive emissions include equipment leaks, evaporative losses from surface impoundments and spills, and releases
from building ventilation systems. Point source air emissions occur through confined air streams such as stacks, vents, ducts, or
pipes.
2. Releases to water include discharges to streams, rivers, lakes, oceans, and other bodies of water. This includes releases from
contained sources, such as industrial process outflow pipes or open trenches. Releases due to runoff, including storm water runoff
are also reported.
3. Underground injection is the subsurface emplacement of fluids through wells including Class I, II, III, IV, or V wells.
4. Total on-site disposal to Class I underground injection Resource Conservation and Recovery Act landfills and other landfills.
5. Includes land treatment, surface impoundments, and other land disposal. Other disposal is the disposal of the toxic chemical to
land at the facility that does not fall into one of the other on-site land releases listed. Other disposal includes such activities as
placement in waste piles and spills or leaks.
6. Disposal of toxic chemicals in waste to off-site locations includes discharges to publicly owned treatment works or disposal at
other off-site facilities. Other off-site disposal facilities may include underground injection, landfills, solidification/stabilization (metals),
water treatment (metals), surface impoundments, land treatment, waste broker, or other unknown off-site facilities.
3-3
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-3. Reported Disposal or Release of Alachlor (2013; pounds)
HAWAII
100
ALASKA
Legend
Total On-Site and Off-Site Disposal or Other Releases (lbs.)
Alachlor
PUERTO RICO
100 200 300 400
Miles
-20
Source: IJSEPA, 2015
3.1.2 Barium and Barium Compounds
Reported releases and disposal of barium were approximately 5.6 million pounds in 2013.
Exhibit 3-4 and Exhibit 3-5 show that Arizona reported the greatest release and disposal of 2.8
million pounds (50%) followed by Kansas (0.8 million pounds), Oregon (0.3 million pounds),
and Wyoming (0.6 million pounds). In total, 4.6 million pounds of barium (82.4%) releases and
disposal came from the electric utilities sector [North American Industry Classification System
(NAICS) 2211] and most were disposed of in on-site landfills (USEPA, 2015). Kentucky
reported the highest release to surface water of 250 pounds
3-4
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-4. Reported Disposal or Release of Barium (2013; pounds)
Total On-
Total Off-
and Off-
On-site
On-site
Total On-
site
site
Surface
Under-
On-site
Other On-
site
Disposal
Disposal
On-site
Water
ground
Landfill
site
Disposal or
or
or
State
Air1
Discharges2
Injection3
Disposal4
Releases5
Releases
Releases6
Releases
Arizona
2,086
0
0
2,778,152
153
2,780,391
0
2,780,391
California
3
0
0
15,132
8
15,143
311
15,453
Colorado
5,299
0
0
18,393
47,677
71,369
ND
71,369
Connecticut
3
0
0
0
0
3
3,399
3,402
Florida
17
0
0
0
0
17
30,167
30,184
Georgia
16
0
0
0
0
16
1,960
1,977
Idaho
1,553
0
0
174,547
1
176,101
ND
176,101
Illinois
0
6
0
10,864
0
10,870
ND
10,870
Indiana
11
0
0
0
0
11
3,491
3,501
Iowa
442
0
0
0
0
442
766
1,208
Kansas
7,448
0
0
143,380
0
150,828
684,672
835,500
Kentucky
844
250
0
0
0
1,094
255
1,349
Louisiana
7
0
0
140,004
0
140,011
1,275
141,286
Michigan
36
0
0
0
0
36
ND
36
Minnesota
3
0
0
0
0
3
28,015
28,018
Nebraska
1,048
0
0
0
17,963
19,011
271,807
290,818
Nevada
3
0
0
54,232
0
54,235
3
54,238
New York
0
117
0
3,723
0
3,840
4,315
8,155
Ohio
45
0
0
95,024
0
95,069
1,432
96,502
Oregon
0
0
0
256,077
0
256,077
262
256,339
South Carolina
5
0
0
0
0
5
28,586
28,591
South Dakota
346
0
0
2,846
0
3,192
ND
3,192
Tennessee
10
0
0
0
0
10
21,996
22,006
Texas
0
10
0
31,461
0
31,472
1,430
32,902
Utah
0
0
0
0
0
0
6,262
6,262
Wyoming
3,410
0
0
0
0
3,410
660,000
663,410
Puerto Rico
0
0
0
0
0
0
1
1
Total
22,636
383
0
3,723,836
65,802
3,812,657
1,750,404
5,563,061
Source: USEPA, 2015
ND: no data reported
1. Includes fugitive and point source air releases. Fugitive emissions are all releases to air that are not released through a confined air
stream. Fugitive emissions include equipment leaks, evaporative losses from surface impoundments and spills, and releases from
building ventilation systems. Point source air emissions occur through confined air streams such as stacks, vents, ducts, or pipes.
2. Releases to water include discharges to streams, rivers, lakes, oceans, and other bodies of water. This includes releases from
contained sources, such as industrial process outflow pipes or open trenches. Releases due to runoff, including storm water runoff are
also reported.
3. Underground injection is the subsurface emplacement of fluids through wells including Class I, II, III, IV, or V wells.
4. Total on-site disposal to Class I underground injection Resource Conservation and Recovery Act landfills and other landfills.
5. Includes land treatment, surface impoundments, and other land disposal. Other disposal is the disposal of the toxic chemical to land
at the facility that does not fall into one of the other on-site land releases listed. Other disposal includes such activities as placement in
waste piles and spills or leaks.
6. Disposal of toxic chemicals in waste to off-site locations includes discharges to publicly owned treatment works or disposal at other
off-site facilities. Other off-site disposal facilities may include underground injection, landfills, solidification/stabilization (metals), water
treatment (metals), surface impoundments, land treatment, waste broker, or other unknown off-site facilities.
3-5
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-5. Reported Disposal or Release of Barium (2013; pounds)
28018
96502
10870 3501
15453
71369
22006
28591
;29o:.
HAWAII
30184
ALASKA
0 100 200 300 400
1 l I l I
Legend
Total On-Site and Off-Site Disposal or Other Releases (lbs.)
Barium
1-8155
| 8156-96502
| 96503 - 835500
¦ 835501 - 2780391
PUERTO RICO
Source: USEPA, 2015
Reported releases and di sposal of barium compounds were approximately 320.6 million pounds
in 2013. Exhibit 3-6 and Exhibit 3-7 show that Utah reported the greatest release and disposal
of 106.2 million pounds (33%) followed by Illinois (18.9 million pounds) and Texas (17.7
million pounds). In total, 62% of the reported releases and disposal came from the electric
utilities sector (NAICS 2211) and 32% came from the metals mining sector (NAICS 2122)
(USEPA, 2015). The total release directly to surface waters in 2013 was approximately one
million pounds. Illinois reported the highest release to surface water of 245,126 pounds followed
by Tennessee (122,755 pounds) and Kentucky (65,285 pounds).
3-6
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-6. Reported Disposal or Release of Barium Compounds (2013; pounds)
Total On-
site
Total Off-
Total On-
Surface
Under-
On-site
Other On-
Disposal or
site
and Off-site
State
Air1
Water
Discharges2
ground
Injection3
Landfill
Disposal4
site
Releases5
Other
Releases
Disposal or
Releases6
Disposal or
Releases
Alabama
38,432
59,789
0
1,357,544
7,203,623
8,659,388
18,387
8,677,775
Alaska
4,582
0
0
302,658
62,644
369,884
332,016
701,900
Arizona
11,222
0
0
3,890,911
1,740,161
5,642,294
8,505
5,650,799
Arkansas
38,708
59,751
0
5,585,929
308,519
5,992,907
24,108
6,017,015
California
987
24
0
949
5
1,965
10,048
12,013
Colorado
5,284
931
0
5,009,452
16,807
5,032,474
1,331,003
6,363,477
Connecticut
1
0
0
0
0
1
46
46
Delaware
387
7,001
0
100,040
0
107,429
8,759
116,187
Florida
14,962
17,253
0
955,953
108,676
1,096,844
61,487
1,158,331
Georgia
26,739
48,673
0
103,413
5,491,030
5,669,855
244,598
5,914,453
Hawaii
24
0
0
0
0
24
146,342
146,366
Idaho
4,971
3
0
84,502
277,029
366,505
63,793
430,298
Illinois
79,374
245,126
0
4,581,218
6,034,451
10,940,169
7,976,699
18,916,869
Indiana
28,801
27,938
0
4,301,383
2,823,815
7,181,937
1,010,572
8,192,509
Iowa
98,588
9,648
0
4,307,547
306,520
4,722,303
1,342,391
6,064,694
Kansas
10,439
3,333
0
4,215,268
192,000
4,421,040
49,179
4,470,219
Kentucky
26,230
65,285
7,938
2,876,150
1,945,163
4,920,766
201,393
5,122,159
Louisiana
50,757
33,131
0
1,884,262
1,972,447
3,940,597
58,295
3,998,892
Maine
2,112
4,500
0
73,404
0
80,016
33,101
113,117
Maryland
1,728
331
0
0
440,580
442,638
653,571
1,096,209
Massachusetts
788
1,440
0
5,320
274
7,822
65,593
73,415
Michigan
61,727
26,886
0
6,983,194
2,873,482
9,945,289
1,889,666
11,834,955
Minnesota
73,065
2,210
0
937,837
8,651,609
9,664,722
1,130,117
10,794,838
Mississippi
2,282
6,744
0
817,313
51,343
877,682
683,974
1,561,656
Missouri
88,822
6,193
0
3,896,682
5,929,364
9,921,061
22,193
9,943,254
Montana
111,563
879
0
8,507,108
117,743
8,737,293
414,955
9,152,248
Nebraska
138,043
4,836
0
5,381,950
24,178
5,549,007
460,697
6,009,704
Nevada
499
0
0
445,343
190,343
636,184
82
636,267
New
Hampshire
204
70
0
1,057
0
1,331
17,836
19,167
New Jersey
1,300
12
0
0
0
1,312
98,200
99,512
New Mexico
5,370
3,076
0
2,954,434
906,486
3,869,366
32,438
3,901,804
New York
4,229
5,515
0
131,127
0
140,871
550,460
691,331
North Carolina
50,267
45,002
0
1,291,254
364,900
1,751,423
979,585
2,731,008
North Dakota
41,633
2,402
0
6,792,719
4,281,851
11,118,605
2,585,053
13,703,658
Ohio
16,872
25,186
0
1,485,200
2,250,113
3,777,371
1,834,243
5,611,614
Oklahoma
9,761
7,844
0
1,534,990
368,755
1,921,350
682,706
2,604,055
Oregon
6,936
1,951
0
540,290
60
549,237
75
549,312
Pennsylvania
14,714
31,179
0
1,660,887
789,462
2,496,241
2,457,885
4,954,126
Rhode Island
5
18
0
0
0
23
9,938
9,961
South Carolina
6,573
38,454
0
287,913
179,532
512,472
272,368
784,840
South Dakota
2,465
0
0
531,311
0
533,776
186,545
720,321
Tennessee
10,896
122,756
0
2,033,878
3,447,661
5,615,191
1,779,612
7,394,803
3-7
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-6. Reported Disposal or Release of Barium Compounds (2013; pounds)
Total On-
site
Total Off-
Total On-
Surface
Under-
On-site
Other On-
Disposal or
site
and Off-site
Water
ground
Landfill
site
Other
Disposal or
Disposal or
State
Air1
Discharges2
Injection3
Disposal4
Releases5
Releases
Releases6
Releases
Texas
66,176
57,547
0
15,592,055
1,682,821
17,398,600
301,767
17,700,367
Utah
5,985
162
0
4,570,241
101,600,158
106,176,546
66,718
106,243,264
Virginia
3,152
37,569
0
915,124
412,292
1,368,137
148,053
1,516,190
Washington
1,278
1,329
0
842,965
2,984
848,556
165,447
1,014,003
West Virginia
13,553
9,408
0
1,982,600
1,265,212
3,270,773
2,387,278
5,658,051
Wisconsin
51,442
13,694
0
378,878
397,189
841,203
4,103,505
4,944,708
Wyoming
68,122
4,082
0
4,637,407
919,594
5,629,205
925,305
6,554,510
Puerto Rico
1,471
0
0
0
0
1,471
1,471
Total
1,303,522
1,039,160
7,938
114,769,660
165,630,875
282,751,155
37,826,587
320,577,743
Source: USEPA, 2015
ND: no data reported
1. Includes fugitive and point source air releases. Fugitive emissions are all releases to air that are not released through a confined air
stream. Fugitive emissions include equipment leaks, evaporative losses from surface impoundments and spills, and releases from
building ventilation systems. Point source air emissions occur through confined air streams such as stacks, vents, ducts, or pipes.
2. Releases to water include discharges to streams, rivers, lakes, oceans, and other bodies of water. This includes releases from
contained sources, such as industrial process outflow pipes or open trenches. Releases due to runoff, including storm water runoff are
also reported.
3. Underground injection is the subsurface emplacement of fluids through wells including Class I, II, III, IV, or V wells.
4. Total on-site disposal to Class I underground injection Resource Conservation and Recovery Act landfills and other landfills.
5. Includes land treatment, surface impoundments, and other land disposal. Other disposal is the disposal of the toxic chemical to land
at the facility that does not fall into one of the other on-site land releases listed. Other disposal includes such activities as placement in
waste piles and spills or leaks.
6. Disposal of toxic chemicals in waste to off-site locations includes discharges to publicly owned treatment works or disposal at other
off-site facilities. Other off-site disposal facilities may include underground injection, landfills, solidification/stabilization (metals), water
treatment (metals), surface impoundments, land treatment, waste broker, or other unknown off-site facilities.
3-8
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-7. Reported Disposal or Release of Barium Compounds (2013; pounds)
1014003
113117
19167
430298
4944708
691331
-73415
4954126
¦99512
116187
¦1096209
1516190-
4470219
2731008
2604055
784840
3901804
: 1561656
3998892
115833*
PUERTO RICO
I I I I I
Miles
° HAWAII
146366
•4.
0 100 200 300 400
Legend
Total On-Site and Off-Site Disposal or Other Releases (lbs.)
Barium Compounds
46 - 784840
784841 -4954126
| 4954127 - 9943254
¦ 9943255 -106243264
701900
ALASKA
Source: USEPA, 2015
3.1.3 Beryllium and Beryllium Compounds
Reported releases and disposal of beryllium were approximately 37,300 pounds in 2013. Exhibit
3-8 and Exhibit 3-9 show that Oregon reported the greatest release and disposal of 16,571
pounds (44.4%) followed by Idaho (12,242 pounds), and Ohio (6,800 pounds). Most beryllium
was reported to be released to air or disposed of in on-site landfills; only 16 pounds were
released to surface waters in 2013.
3-9
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-8. Reported Disposal or Release of Beryllium (2013; pounds)
Total On-
Total Off-
and Off-
Total On-
site
site
Surface
Under-
On-site
Other On-
site
Disposal
Disposal
Water
ground
Landfill
site
Disposal or
or
or
State
Air1
Discharges2
Injection3
Disposal4
Releases5
Releases
Releases6
Releases
Georgia
27
0
0
0
0
27
2
29
Idaho
2
0
0
12,240
0
12,242
0
12,242
Kansas
5
0
0
0
0
5
0
5
Louisiana
133
0
0
0
0
133
0
133
North Carolina
55
0
0
0
0
55
0
55
Ohio
6,800
0
0
0
0
6,800
0
6,800
Oregon
0
0
0
16,571
0
16,571
0
16,571
Pennsylvania
1
16
0
0
0
17
895
912
Tennessee
1
0
0
0
0
1
52
53
Texas
0
0
0
499
0
499
0
499
Total
7,024
16
0
29,309
0
36,349
950
37,299
Source: USEPA, 2015
ND: no data reported
1. Includes fugitive and point source air releases. Fugitive emissions are all releases to air that are not released through a confined air
stream. Fugitive emissions include equipment leaks, evaporative losses from surface impoundments and spills, and releases from
building ventilation systems. Point source air emissions occur through confined air streams such as stacks, vents, ducts, or pipes.
2. Releases to water include discharges to streams, rivers, lakes, oceans, and other bodies of water. This includes releases from
contained sources, such as industrial process outflow pipes or open trenches. Releases due to runoff, including storm water runoff are
also reported.
3. Underground injection is the subsurface emplacement of fluids through wells including Class I, II, III, IV, or V wells.
4. Total on-s-Site disposal to Class I underground injection Resource Conservation and Recovery Act landfills and other landfills.
5. Includes land treatment, surface impoundments, and other land disposal. Other disposal is the disposal of the toxic chemical to land
at the facility that does not fall into one of the other on-site land releases listed. Other disposal includes such activities as placement in
waste piles and spills or leaks.
6. Disposal of toxic chemicals in waste to off-site locations includes discharges to publicly owned treatment works or disposal at other
off-site facilities. Other off-site disposal facilities may include underground injection, landfills, solidification/stabilization (metals), water
treatment (metals), surface impoundments, land treatment, waste broker, or other unknown off-site facilities.
3-10
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-9. Reported Disposal or Release of Beryllium (2013; pounds)
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-10. Reported Disposal or Release of Beryllium Compounds (2013;
Total On-
Total Off-
and Off-
On-site
On-site
Total On-
site
site
Surface
Under-
On-site
Other On-
site
Disposal
Disposal
On-site
Water
ground
Landfill
site
Disposal or
or
or
State
Air1
Discharges2
Injection3
Disposal4
Releases5
Releases
Releases6
Releases
Arizona
19
0
0
6,022
0
6,041
0
6,041
Florida
60
0
0
2,231
2
2,293
363
2,656
Georgia
45
0
0
0
10,000
10,045
0
10,045
Illinois
45
12
0
34,059
124
34,240
3,195
37,435
Indiana
100
42
0
1,407
40,400
41,949
9,841
51,790
Kansas
6
0
0
2
0
8
0
8
Kentucky
390
22
0
18,140
41,632
60,184
0
60,184
Michigan
19
31
0
0
6,200
6,250
3
6,253
Montana
20
0
0
7,910
0
7,930
50
7,980
New Mexico
32
0
0
17,590
9,588
27,210
7
27,217
North Carolina
52
12
0
14,630
1,090
15,784
0
15,784
Ohio
299
26
0
47,682
23,766
71,773
20,809
92,582
Pennsylvania
70
1
0
0
0
71
10,219
10,290
South Carolina
6
12
0
57
1,352
1,427
0
1,427
Tennessee
11
0
0
4,200
1,947
6,158
0
6,158
Texas
67
0
0
52,325
3,805
56,197
0
56,197
Utah
27
0
0
104
11,083
11,214
66,359
77,573
West Virginia
51
0
0
11,210
2,565
13,826
11,000
24,826
Total
1,319
158
0
217,569
153,554
372,599
121,846
494,446
aounds)
Source: USEPA, 2015
ND: no data reported
1. Includes fugitive and point source air releases. Fugitive emissions are all releases to air that are not released through a confined air
stream. Fugitive emissions include equipment leaks, evaporative losses from surface impoundments and spills, and releases from
building ventilation systems. Point source air emissions occur through confined air streams such as stacks, vents, ducts, or pipes.
2. Releases to water include discharges to streams, rivers, lakes, oceans, and other bodies of water. This includes releases from
contained sources, such as industrial process outflow pipes or open trenches. Releases due to runoff, including storm water runoff are
also reported.
3. Underground injection is the subsurface emplacement of fluids through wells including Class I, II, III, IV, or V wells.
4. Total on-site disposal to Class I underground injection Resource Conservation and Recovery Act landfills and other landfills.
5. Includes land treatment, surface impoundments, and other land disposal. Other disposal is the disposal of the toxic chemical to land
at the facility that does not fall into one of the other on-site land releases listed. Other disposal includes such activities as placement in
waste piles and spills or leaks.
6. Disposal of toxic chemicals in waste to off-site locations includes discharges to publicly owned treatment works or disposal at other
off-site facilities. Other off-site disposal facilities may include underground injection, landfills, solidification/stabilization (metals), water
treatment (metals), surface impoundments, land treatment, waste broker, or other unknown off-site facilities.
3-12
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-11. Reported Disposal or Release of Beryllium Compounds (2013;
pounds)
10290
37435
15784
27217
10045
HAWAII
ALASKA
0 100 200 300 400
Legend
Total On-Site and Off-Site Disposal or Other Releases (lbs.)
Beryllium Compounds
5-55
56-912
| 913-6800
¦ 6801 - 16571
PUERTO RICO
Source: USEPA, 2015
3.1.4 2,4-D
Reported releases and disposal of 2,4-D were approximately 2,363 pounds in 2013. Exhibit
3-12 and Exhibit 3-13 show that Missouri reported the greatest release and disposal of 866
pounds (37%) followed by Iowa (500 pounds), and Ohio (375 pounds). The majority of 2,4-D
was released to air or disposed off-site; the total release directly to surface water in 2013 was
only 9 pounds.
3-13
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-12. Reported Disposal or Release of 2,4-D (2013; pounds)
On-site
On-site
Total Off-
Total On-
Surface
Under-
On-site
Other On-
Total On-site
site
and Off-site
On-site
Water
ground
Landfill
site
Disposal or
Disposal or
Disposal or
State
Air1
Discharges2
Injection3
Disposal4
Releases5
Releases
Releases6
Releases
Illinois
43
0
0
0
0
43
9
52
Iowa
500
0
0
0
0
500
ND
500
Kansas
10
0
0
0
0
10
176
186
Michigan
110
9
0
49
0
168
ND
168
Missouri
179
0
0
0
0
179
687
866
Montana
10
0
0
0
0
10
55
65
Nebraska
6
0
0
0
0
6
ND
6
Ohio
262
0
0
0
0
262
113
375
Texas
30
0
0
0
0
30
ND
30
Utah
115
0
0
0
0
115
ND
115
Total
1,264
9
0
49
0
1,323
1,040
2,363
Source: USEPA, 2015
ND: no data reported
1. Includes fugitive and point source air releases. Fugitive emissions are all releases to air that are not released through a confined
air stream. Fugitive emissions include equipment leaks, evaporative losses from surface impoundments and spills, and releases from
building ventilation systems. Point source air emissions occur through confined air streams such as stacks, vents, ducts, or pipes.
2. Releases to water include discharges to streams, rivers, lakes, oceans, and other bodies of water. This includes releases from
contained sources, such as industrial process outflow pipes or open trenches. Releases due to runoff, including storm water runoff
are also reported.
3. Underground injection is the subsurface emplacement of fluids through wells including Class I, II, III, IV, or V wells.
4. Total on-site disposal to Class I underground injection Resource Conservation and Recovery Act landfills and other landfills.
5. Includes land treatment, surface impoundments, and other land disposal. Other disposal is the disposal of the toxic chemical to
land at the facility that does not fall into one of the other on-site land releases listed. Other disposal includes such activities as
placement in waste piles and spills or leaks.
6. Disposal of toxic chemicals in waste to off-site locations includes discharges to publicly owned treatment works or disposal at
other off-site facilities. Other off-site disposal facilities may include underground injection, landfills, solidification/stabilization (metals),
water treatment (metals), surface impoundments, land treatment, waste broker, or other unknown off-site facilities.
3-14
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-13. Reported Disposal or Release of 2,4-D Compounds (2013; pounds)
HAWAII
Legend
Total On-Site and Off-Site Disposal or Other Releases (lbs.)
2,4-D
6 - 65
~ 66 - 500
ALASKA
PUERTO RICO
Source: IJSEPA, 2015
3.1.5 Lindane
As shown in Exhibit 3-14 and Exhibit 3-15, 9,079 pounds of lindane were reportedly released
and disposed of in 2013 from five states. Hazardous Waste and Solvent Recovery facilities
(NAICS 562) in Indiana disposed the largest quantity of lindane (9,032 pounds) at off-site
facilities.
3-15
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-14. Reported Disposal or Release of Lindane (2013; pounds)
On-site
On-site
Total Off-
Total On- and
Surface
Under-
On-site
Other On-
Total On-site
site
Off-site
On-site
Water
ground
Landfill
site
Disposal or
Disposal or
Disposal or
State
Air1
Discharges2
Injection3
Disposal4
Releases5
Releases
Releases6
Releases
Indiana
0
0
0
0
0
0
9,032
9,032
Nebraska
3
0
0
0
0
3
ND
3
Ohio
4
0
0
0
0
4
1
5
Texas
31
0
0
0
0
31
ND
31
Utah
8
0
0
0
0
8
ND
8
Total
46
0
0
0
0
46
9,033
9,079
Source: USEPA, 2015
ND: no data reported
1. Includes fugitive and point source air releases. Fugitive emissions are all releases to air that are not released through a confined
air stream. Fugitive emissions include equipment leaks, evaporative losses from surface impoundments and spills, and releases from
building ventilation systems. Point source air emissions occur through confined air streams such as stacks, vents, ducts, or pipes.
2. Releases to water include discharges to streams, rivers, lakes, oceans, and other bodies of water. This includes releases from
contained sources, such as industrial process outflow pipes or open trenches. Releases due to runoff, including storm water runoff
are also reported.
3. Underground injection is the subsurface emplacement of fluids through wells including Class I, II, III, IV, or V wells.
4. Total on-site disposal to Class I underground injection Resource Conservation and Recovery Act landfills and other landfills.
5. Includes land treatment, surface impoundments, and other land disposal. Other disposal is the disposal of the toxic chemical to
land at the facility that does not fall into one of the other on-site land releases listed. Other disposal includes such activities as
placement in waste piles and spills or leaks.
6. Disposal of toxic chemicals in waste to off-site locations includes discharges to publicly owned treatment works or disposal at other
off-site facilities. Other off-site disposal facilities may include underground injection, landfills, solidification/stabilization (metals), water
treatment (metals), surface impoundments, land treatment, waste broker, or other unknown off-site facilities.
3-16
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-15. Reported Disposal or Release of Lindane (2013)
HAWAII
100
Legend
Total On-Site and Off-Site Disposal or Other Releases (lbs.)
Lindane
ALASKA
PUERTO RICO
0 100 200 300 400
-31
Miles
32 - 9032
Source: IJSEPA, 2015
3.1.6 Picloram
Reported releases and disposal of picloram were approximately 245 pounds in 2013. As shown
in Exhibit 3-16 and Exhibit 3-17, only Mi chigan and Texas reported releases. All of the
reported releases and disposal came from the chemical sector (NAICS 325) and most was
disposed of in on-site landfills (USEPA, 2015). The total release directly to surface water in
2013 was only 18 pounds, all of which was reported in Michigan.
3-17
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-16. Reported Disposal or Release of Picloram (2013; pounds)
Total Off-
On-site
On-site
site
Total On- and
Surface
Under-
On-site
Other On-
Total On-site
Disposal
Off-site
On-site
Water
ground
Landfill
site
Disposal or
or
Disposal or
State
Air1
Discharqes2
Injection3
Disposal4
Releases5
Releases
Releases6
Releases
Michigan
23
18
0
0
0
41
41
Texas
204
0
0
0
0
204
204
Total
227
18
0
0
0
245
0
245
Source: USEPA, 2015
ND: no data reported
1. Includes fugitive and point source air releases. Fugitive emissions are all releases to air that are not released through a confined
air stream. Fugitive emissions include equipment leaks, evaporative losses from surface impoundments and spills, and releases from
building ventilation systems. Point source air emissions occur through confined air streams such as stacks, vents, ducts, or pipes.
2. Releases to water include discharges to streams, rivers, lakes, oceans, and other bodies of water. This includes releases from
contained sources, such as industrial process outflow pipes or open trenches. Releases due to runoff, including storm water runoff
are also reported.
3. Underground injection is the subsurface emplacement of fluids through wells including Class I, II, III, IV, or V wells.
4. Total on-site disposal to Class I underground injection Resource Conservation and Recovery Act landfills and other landfills.
5. Includes land treatment, surface impoundments, and other land disposal. Other disposal is the disposal of the toxic chemical to
land at the facility that does not fall into one of the other on-site land releases listed. Other disposal includes such activities as
placement in waste piles and spills or leaks.
6. Disposal of toxic chemicals in waste to off-site locations includes discharges to publicly owned treatment works or disposal at
other off-site facilities. Other off-site disposal facilities may include underground injection, landfills, solidification/stabilization (metals),
water treatment (metals), surface impoundments, land treatment, waste broker, or other unknown off-site facilities.
3-18
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-17. Reported Disposal or Release of Picloram (2013; pounds)
HAWAII
ALASKA
0 00 200 300 400
Legend
Total On-Site and Off-Site Disposal or Other Releases (lbs.)
Picloram
PUERTO RICO
Source: IJSEPA, 2015
3.1.7 1,1,1 -T richloroethane
Reported releases and disposal of 1,1,1-trichloroethane were approximately 110,000 pounds in
2013. Exhibit 3-18 and Exhibit 3-19 show that Louisiana reported the greatest release and
disposal of 51,461 pounds (47%) followed by New Mexico (22,413 pounds), and Oregon
(16,235 pounds). In Louisiana all releases and disposal came from the chemical sector (NAICS
325) and most was released into the air (USEPA, 2015). The total release directly to surface
water in 2013 was 1,371 pounds, 1,300 of which were reported by Louisiana.
3-19
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-18. Reported Disposal or Release of 1,1,1 -Trichloroethane (2013; pounds)
Total Off-
Total On-
On-site
On-site
Total On-site
site
and Off-site
Surface
Under-
On-site
Other On-
Disposal or
Disposal or
Disposal or
On-site
Water
ground
Landfill
site
Other
Other
Other
State
Air1
Discharqes2
Injection3
Disposal4
Releases5
Releases
Releases6
Releases
Arkansas
2
0
0
0
0
2
ND
2
Illinois
500
0
0
0
0
500
ND
500
Indiana
1,506
0
0
0
0
1,506
ND
1,506
Kentucky
706
61
0
0
0
767
ND
767
Louisiana
50,161
1,300
0
0
0
51,461
0
51,461
Nebraska
39
0
0
0
0
39
0
39
New Jersey
2,009
10
0
0
0
2,019
ND
2,019
New Mexico
465
0
0
0
21,948
22,413
ND
22,413
New York
1
0
0
0
0
1
ND
1
Ohio
77
0
0
0
0
77
235
312
Oklahoma
0
0
0
12,908
0
12,908
ND
12,908
Oregon
11
0
0
16,224
0
16,235
ND
16,235
Pennsylvania
500
0
0
0
0
500
ND
500
South Carolina
2
0
0
0
0
2
ND
2
Texas
917
0
0
1
0
918
250
1,168
Utah
9
0
0
0
0
9
97
106
Washington
73
0
0
0
0
73
0
73
Total
56,978
1,371
0
29,133
21,948
109,430
582
110,012
Source: USEPA, 2015
ND: no data reported
1. Includes fugitive and point source air releases. Fugitive emissions are all releases to air that are not released through a confined
air stream. Fugitive emissions include equipment leaks, evaporative losses from surface impoundments and spills, and releases from
building ventilation systems. Point source air emissions occur through confined air streams such as stacks, vents, ducts, or pipes.
2. Releases to water include discharges to streams, rivers, lakes, oceans, and other bodies of water. This includes releases from
contained sources, such as industrial process outflow pipes or open trenches. Releases due to runoff, including storm water runoff
are also reported.
3. Underground injection is the subsurface emplacement of fluids through wells including Class I, II, III, IV, or V wells.
4. Total on-site disposal to Class I underground injection Resource and Conservations Recovery Act landfills and other landfills.
5. Includes land treatment, surface impoundments, and other land disposal. Other disposal is the disposal of the toxic chemical to
land at the facility that does not fall into one of the other on-site land releases listed. Other disposal includes such activities as
placement in waste piles and spills or leaks.
6. Disposal of toxic chemicals in waste to off-site locations includes discharges to publicly owned treatment works or disposal at
other off-site facilities. Other off-site disposal facilities may include underground injection, landfills, solidification/stabilization (metals),
water treatment (metals), surface impoundments, land treatment, waste broker, or other unknown off-site facilities.
3-20
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-19. Reported Disposal or Release of 1,1,1 -Trichloroethane (2013;
pounds)
HAWAII
Legend
ALASKA
Total On-Site and Off-Site Disposal or Other Releases (lbs.)
1,1,1 -Trichloroethane
1 - 500
~~| 501 -2019
PUERTO RICO
2020-22413
22414-51461
Source: USEPA, 2015
3-21
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
3.1.8 1,2,4-Trichlorobenzene
Reported releases and disposal of 1,2,4-trichlorobenzene were approximately 8,000 pounds in
2013. Exhibit 3-20 and Exhibit 3-23 and show that Ohio reported the greatest release and
disposal of 6,844 pounds (84%) followed by West Virginia (955 pounds), and Pennsylvania (273
pounds). In Ohio, all releases and disposal came from the chemical sector (NAICS 325) and the
hazardous waste/chemical recovery sector (NAICS 562). There were no reported releases
directly to surface water in 2013.
Exhibit 3-20. Reported Disposal or Release of 1,2,4-Trichlorobenzene (2013; pounds)
On-site
On-site
Total Off-
Total On-
Surface
Under-
On-site
Other On-
Total On-site
site
and Off-site
On-site
Water
ground
Landfill
site
Disposal or
Disposal or
Disposal or
State
Air1
Discharges2
Injection3
Disposal4
Releases5
Releases
Releases6
Releases
Alabama
10
0
0
0
0
10
10
Louisiana
12
0
0
0
0
12
2
14
Ohio
6,573
0
0
0
0
6,573
271
6,844
Pennsylvania
23
0
0
0
0
23
250
273
Texas
46
0
0
0
0
46
46
West Virginia
955
0
0
0
0
955
955
Total
7,618
0
0
0
0
7,618
523
8,141
Source: USEPA, 2015
ND: no data reported
1. Includes fugitive and point source air releases. Fugitive emissions are all releases to air that are not released through a confined
air stream. Fugitive emissions include equipment leaks, evaporative losses from surface impoundments and spills, and releases from
building ventilation systems. Point source air emissions occur through confined air streams such as stacks, vents, ducts, or pipes.
2. Releases to water include discharges to streams, rivers, lakes, oceans, and other bodies of water. This includes releases from
contained sources, such as industrial process outflow pipes or open trenches. Releases due to runoff, including storm water runoff
are also reported.
3. Underground injection is the subsurface emplacement of fluids through wells including Class I, II, III, IV, or V wells.
4. Total on-site disposal to Class I underground injection Resource Conservation and Recovery Act landfills and other landfills.
5. Includes land treatment, surface impoundments, and other land disposal. Other disposal is the disposal of the toxic chemical to
land at the facility that does not fall into one of the other on-site land releases listed. Other disposal includes such activities as
placement in waste piles and spills or leaks.
6. Disposal of toxic chemicals in waste to off-site locations includes discharges to publicly owned treatment works or disposal at
other off-site facilities. Other off-site disposal facilities may include underground injection, landfills, solidification/stabilization (metals),
water treatment (metals), surface impoundments, land treatment, waste broker, or other unknown off-site facilities.
3-22
-------
Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-21. Reported Disposal or Release of 1,2,4-Trichlorobenzene (2013;
pounds)
273
955
46
HAWAII
ALASKA
Legend
Total On-Site and Off-Site Disposal or Other Releases (lbs.)
1,2,4-Trichlorobenzene
10-46
~~I 47 - 955
PUERTO RICO
100 200 300 400
Miles
956 - 6,844
Source: USEPA, 2015
3.2 Pesticide Usage Estimates
A second source of environmental release information is the USGS estimates of pesticide use.
The USGS estimates annual pesticide use at the county level based on crop-specific usage rates
(pounds per acre) obtained via survey and county-level crop production data obtained from the
U.S. Department of Agriculture (USDA; Baker and Stone, 2015). The usage rates reflect
practices at a sample of farms in each of 15 USDA Crop Reporting Districts. Whenever the
sample usage rate was zero, the USDA used two extrapolation approaches to generate upper and
lower bounds the uncertainty estimates. The "low" estimate reflects a usage rate of zero and the
"high" estimate reflects usage rates in adjacent Crop Reporting Districts.
Estimates compiled for 2012 include several of the contaminants in this report: alachlor, 2,4-D,
diquat, lindane, and picloram. The following figures come from the USGS online data analysis
tool, which generates application rate maps and annual national usage charts by pesticide for
both the low and high estimate scenarios, labeled EPest-Low and EPest-High in the USGS
figures.
3-23
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Occurrence Analysis for Potential Source Waters
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3.2.1 Alachlor
Exhibit 3-22 and Exhibit 3-23 show that the alachlor application rates are highest in the
Midwest, with primary application to corn and soybean crops. Annual usage rates have declined
substantially from more than 50 million pounds in 1992 to less than 10 million pounds in 2012.
Exhibit 3-22. Lower Bound Estimated Agricultural Use of Alachlor, 2012
EPest-Low
Estimated use
agricultural land, in
pounds per square mile
I I < 0.15
I I 0.15- 1 72
¦ 1.73 -9.71
H > 9.71
I I No estimated use
Use by Year and Crop
n^r"F=
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Occurrence Analysis for Potential Source Waters
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Exhibit 3-23. Upper Bound Estimated Agricultural Use of Alachlor, 2012
Estimated use
agricultural land, in
pounds per square mile
I I < 0.15
~ 0.15- 1.72
H 1.73-9.71
^¦>9.71
I I No estimated use
EPest-High
Use by Year and Crop
¦
20-]
10
Lf> ID
cn
<7> CT)
Ot-«VJ
o o o
ooo
(M (VI M
MTiniiJNCDfflO'— <\1
ooooooo>—>—•—
oooooooooo
i—i Other crops
i i Pasture and nay
i i AlTara
¦1 Orchards and grapes
i—i Rioe
I I Vegetables and fruft
Cotton
gg vmeat
r—i Soyoeans
I I Com
Source: USGS, 2015b
3-25
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Occurrence Analysis for Potential Source Waters
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3.2.2 2,4-D
Exhibit 3-24 and Exhibit 3-25 show widespread 2,4-D application rates primarily in the
Midwest, South, and Southeastern regions, with primary application to pasture and row crops
(corn, soybeans, wheat). Annual usage rates are in the 30 to 40 million pounds range throughout
the period
Exhibit 3-24. Lower Bound Estimated Agricultural Use of 2,4-D, 2012
EPest-Low
Estimated use
agricultural land, in
pounds per square mile
~ <2.85
I I 2 85-9.88
HI 9.89 - 25.83
HI > 25.83
I I No estimated use
Use by Year and Crop
ifii
l^j Other crops
i—i Pasture and nay
czi Allan
B Orchards and grapes
CZI Woe
I I Vegetables ana Trull
Hi Cotton
¦i weal
is—i soybeans
l l Corn
0'—<\J
ci(7iffioffi(n
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 3-25. Upper Bound Estimated Agricultural Use of 2,4-D, 2012
EPest-High
Estimated use
agricultural land, in
pounds per square mile
I I < 2.85
~ 2.85 - 9.88
¦I 9,89 -25.83
HI >25.83
I I No estimated use
Use by Year and Crop
i—i Other crops
i Pasture and nay
CH Airaifa
Hi Orchards and grapes
CD Woe
IZU vegetal*es ana fruit
Cotton
IH V/neat
i—i Soybeans
I I Com
OlOKJlOlOKJlOlOlOOaOOOOOOOr-r-r
ClOicriaimcrioxjiQoooooooooooo
Source: USGS, 2015b
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Occurrence Analysis for Potential Source Waters
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3.2.3 Diquat
Exhibit 3-26 and Exhibit 3-27 show diquat application rates primarily in the Northern latitudes,
especially in the Great Lakes states. The pesticide is primarily applied to vegetables and fruit.
Uncertainty regarding 2,4-D application rates for alfalfa predominate differences between the
low and high use estimates. Annual usage rates are around 0.2 million pounds for the last decade.
Exhibit 3-26. Lower Bound Estimated Agricultural Use of Diquat, 2012
EPest-Low
f
Estimated use on
agricultural land, in
pounds per square mile
~ <0.01
~ 0.01 -0.02
0.03 - 0.04
M > 0.04
I I No estimated use
0.6
0 5-
0.4-
0.3
0 2
0.1
0,0
Use by Year and Crop
CM CO
O CD
cncn
i—i Other crops
i—i Pasture and hay
Aifafa
IB Orchards and grapes
L J
i i vegetattes ana truit
H Ccttor
B wneat
i—i soy&eans
I I Com
Tlfl(0SC5OT—N
ffi0ic(i(jio-
OlOKFIOKnOlOOOOOOOOOOOOQ
— t-t—t—r-T-(\j(\j<\jc\jr\jr»j(\j<\i<\j<\j<\jf\jrsj
Source: USGS, 2015b
3-28
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Occurrence Analysis for Potential Source Waters
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Estimated use on- ___[
agricultural land, in
pounds per square mile
I I <0.01
~ 0.01 -0.02
0.03 - 0.04
Exhibit 3-27. Upper Bound Estimated Agricultural Use of Diquat, 2012
£ EPest-High
k i&iPCr. f\
H > 0.04
I I No estimated use
Use by Year and Crop
r
I—I Other crops
Hi Pasture ana nay
i—i Aifafa
H Orctiards ana grapes
CZ3 woe
en vegetatxes aria fruit
M Ccttor
H wneat
i—i SoyDeans
I I Com
5tin(DNCDcnat-MCOtinu)rvG3cr50i-(\j
lOICIOlOlCDCnOOOOOOOOOOi-'-r-
)Ol5l«l«lfflfflOOOOOOOOOOOOO
Source: USGS, 2015b
3-29
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Occurrence Analysis for Potential Source Waters
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3.2.4 Lindane
Exhibit 3-28 shows that lindane use ended in 2011. Lindane application to corn occurred from
2004 to 2010. Prior to that, applications to orchards and grapes dominated use, especially for the
lower bound estimates. The higher bound estimates included corn and wheat applications.
Exhibit 3-28. Lower and Upper Bound Estimated Agricultural Use of Lindane, 2012
Use by Year and Crop
| 0.02-
kH
i—i Other crops
i i P35IL "0 and nay
i—i Alfafa
¦H Orcnards and trapes
l—l Rice
I I vegetatteB ana 1wit
i—i Cottar
H wne&t
I—i SovCeans
l l Com
(si«^rmtoKojenoT-(Mco^-in«)Kei3cnoi-M
ffiOKnOimClOlfflOOOOOOOOOOr-i-r
OlOjanJlOlfflClOlOOOOOOOQOOOUO
*— '— T— »— r— r— i— c\l (\J C\J M (M (VI fM (\l (\J (\l (\i r^oi-CM
ciOTcnooooooooocti-»-i-
COOlOlOOdOOOOCOOOOO
'— i— i—
Source: USGS, 2015b
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Occurrence Analysis for Potential Source Waters
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3.2.5 Picloram
Exhibit 3-29 and Exhibit 3-30 show picloram application primarily in the Great Plains states
and the South. Picloram is primarily applied to pasture. Annual usage rates are somewhat lower
in the last three years, but generally range from 1 to 2 million pounds in the low estimates.
Exhibit 3-29. Lower Bound Estimated Agricultural Use of Picloram, 2012
EPest-Low
Estimated use
agricultural land, in
pounds per square mile
I I < 0 06
I I 0.06 - 0.38
¦10.39-1.92
1.92
I I No estimated use
Use by Year and Crop
i—i Other crops
r—i Pasture ana nay
i—i AITara
¦¦ Orchards and japes
a Rice
I I VegetaHesanflirult
m Cotton
H wneat
i—i sovceans
I I Com
ocjoocricnaxTsooooooooooT—t—i—
oioiOTcnaiCTicnoiooooooooooooo
Source: USGS, 2015b
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Occurrence Analysis for Potential Source Waters
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Exhibit 3-30. Upper Bound Estimated Agricultural Use
EPest-High
Of
Picloram, 2012
Estimated use
agricultural land, in
pounds per square mile
I I <0.06
I I 0 06 -0.38
M 0,39 -1.92
¦¦> 1.92
I I No estimated use
Use by Year and Crop
j£ 2.5
1.5
0 0J
HI
i—i Overcrops
¦¦ Pa&lure ana nay
i—i Altera
¦i orchards and grapes
II | CZJ vegetataes *>a truit
Cottor
M v/neal
i~i Soybeans
III m Com
fSJCO *
go en e
o>cr> c
lO CO
en en
O) 0)
Co c
cn cn c
cn cn c
3f-fMCT?-mu3KCOC50t-(M
300000Q0QQ1— i— »—
SOOOOOOOOOOOO
Source: USGS, 2015b
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Occurrence Analysis for Potential Source Waters
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4. Contaminant Occurrence Data Sources
EPA obtained data from two sources that provide information on contaminant occurrence in
source water: USGS' NAWQA Program and USDA's Pesticide Data Program (PDP) water
monitoring survey. This section provides background information on these three sources as well
as occurrence summary data for the contaminants of interest.
4.1 NAWQA
In 1991, USGS implemented the NAWQA Program, in part, to characterize the condition of
streams, rivers, and ground water in the United States. For the NAWQA Program, the USGS
conducted interdisciplinary assessments, including water chemistry, hydrology, land use, stream
habitat, and aquatic life, and established a baseline understanding of water-quality conditions in
51 of the Nation's river basins and aquifers, referred to as Study Units (USGS, 2006a). Exhibit
4-1 depicts these study units.
USGS selected these Study Units to reflect important hydrologic and ecological resources;
critical sources of contaminants, including agricultural, urban, and natural sources; and a high
percentage of population served by municipal water supply and irrigated agriculture. These areas
account for more than 70% of total water use (excluding thermoelectric and hydropower) and
more than 50% of the supply of drinking water (Gilliom et al., 2006).
The Study-Unit design used a rotational sampling scheme; therefore, sampling intensity varied
year to year at the different sites. During the first decade, 20 investigations began in 1991; 16 in
1994; and 15 in 1997. During the time period 2001-2012, rotational monitoring continued in 42
of the 51 Study Units.
USGS has made most of this data available through the NAWQA Warehouse (USGS, 2015a).
EPA analyzed all available water quality sampling data for the contaminants of interest. EPA
selected the maximum reported concentration for each contaminant analyzed at each location for
analysis purposes. The results shown below are based on these maximum concentrations and,
therefore, represent upper bounds on contaminant occurrence in the NAWQA database.
4-1
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Occurrence Analysis for Potential Source Waters
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Exhibit 4-1. NAWQA Study Units
NAWQA Study Units
1
Acadian-Pontchartrain Drainages
27
New England Coastal Basins
2
Albemarle-Pamlico Drainage Basin
28
Northern Rockies Intermontane Basins
3
Allegheny and Monongahela River Basins
29
Ozark Plateaus
4
Apalachicola-Chattahoochee-Flint River Basin
30
Potomac River Basin
5
Central Arizona Basins
31
Puget Sound Basin
6
Central Columbia Plateau
32
Red River of the North Basin
7
Central Nebraska Basins
33
Rio Grande Valley
8
Connecticut, Housatonic, and Thames River Basins
34
Sacramento River Basin
9
Cook Inlet Basin
35
San Joaquin-Tulare Basins
10
Delaware River Basin
36
Santa Ana Basin
11
Delmarva Peninsula
37
Santee River Basin and Coastal Drainages
12
Eastern Iowa Basins
38
South-Central Texas
13
Georgia-Florida Coastal Plain
39
South Platte River Basin
14
Great and Little Miami River Basins
40
Southern Florida
15
Great Salt Lake Basins
41
Trinity River Basin
16
Hudson River Basin
42
Upper Colorado River Basin
17
Island of Oahu
43
Upper Illinois River Basin
18
Kanawha-New River Basins
44
Upper Mississippi River Basin
19
Lake Erie-Lake Saint Clair Drainages
45
Upper Snake River Basin
20
Long Island-New Jersey Coastal Drainages
46
Upper Tennessee River Basin
21
Lower Illinois River Basin
47
Western Lake Michigan Drainages
22
Lower Susquehanna River Basin
48
White River Basin
23
Lower Tennessee River Basin
49
Willamette Basin
24
Las Vegas Valley Area and the Carson and Truckee River Basins
50
Yakima River Basin
25
Mississippi Embayment
51
Yellowstone River Basin
26
Mobile River Basin
Source: USGS, 2006b.
4.2 PDF
The USD A established the PDP in 1991 to collect data pertaining to pesticide residues in food
consumed by infants and children. In 1996, Congress expanded the program to include pesticide
residues in drinking water. Implementation of this portion of the program began in 2001 and
ended in 2013.
NAWQA Study Units
1 | Initiated 1991
Initiated 1994
1 I Initiated 1997
High Plains Regional Ground
Water Study, initiated 1999
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Occurrence Analysis for Potential Source Waters
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The USDA collects and publishes annual databases. Each database contains:
• residual concentrations of more than 300 pesticides in drinking water, raw food, and
processed food
• results from consumables originating in 43 countries, 50 states, Washington D.C., and
Puerto Rico
The drinking water data in the PDP provide information to support the Food Quality Protection
Act authorized in 1996 by Congress. When data collection began in 2001, USDA limited
sampling to treated water at community water systems in New York and California. In 2002,
monitoring efforts expanded to include five additional systems in Colorado, Kansas, and Texas;
these locations were eliminated after 2003. The study expanded again in 2004 to include systems
in Michigan, North Carolina, Ohio, Oregon, Pennsylvania, and Washington.
Although the USDA collects both raw water and treated water samples, the data reported below
reflects only the raw water samples, which are better indicators of source water quality. The
treated water samples reflect the effects of water treatment on contaminant removal. For years of
2009 through 2013, the PDP data also include a few samples taken from source waters of schools
and day care centers. Because these facilities may be classified as non-transient, non-community
water systems that are subject to most of the same drinking water standards as a municipal
system, EPA included those samples in the occurrence estimates below.
4.3 Contaminant Occurrence
The following sections discuss the occurrence of contaminants of interest, and present summary
data from the NAWQA and PDP databases. Each summary table juxtaposes the occurrence data
with the current MCLG value (or MCL value when it is greater than the MCLG) and one or more
possible MCLG values that are based on new health risk information. EPA also developed maps
that plot the NAWQA data to demonstrate the spatial extent of the sampling locations and
occurrence results.
EPA did not identify any readily available water quality data for diquat. The Agency, therefore,
obtained available information on diquat use and environmental fate and transport to characterize
potential source water occurrence.
4.3.1 Alachlor
Exhibit 4-2 provides comparisons of the maximum alachlor concentrations found at locations in
the NAWQA database with the current MCL (which is greater than the MCLG of zero) and the
possible MCLG value. The maximum concentrations at less than 0.4% of NAWQA sampling
locations exceed the current MCL and the maximum concentration at only one location exceeds
the possible MCLG. Exhibit 4-3 presents a spatial representation of the NAWQA data. Exhibit
4-4 shows alachlor raw water concentrations from the PDP database. None of the samples
contained alachlor concentrations that exceeded either the current MCL or possible MCLG.
Together, data from these sources indicate minimal occurrence of this contaminant above the
current MCLG and the higher possible MCLG value.
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Occurrence Analysis for Potential Source Waters
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Exhibit 4-2. Summary of Alachlor Occurrence in NAWQA - Number and Percent of
Locations by Location Type
Surface Water
Ground Water
Other
Total
Occurrence Result
Locations
Locations
Locations
Locations
Total locations
2,371 (100%)
8,702 (100%)
211 (100%)
11,284 (100%)
All samples are nondetects1
1,813(76.5%)
8,578 (98.6%)
203 (96,2%)
10,594 (93.9%)
At least one detection
558 (23.5%)
124(1,4%)
8 (3.8%)
690 (6.1%)
Maximum concentration exceeds
current MCL2 (0.002 mg/L)
33(1.4%)
4 (<0.1 %)
0 (0%)
37 (0.3%)
Maximum concentration exceeds
possible MCLG (0.04 mg/L)
1 (<0.1 %)
0 (0%)
0 (0%)
1 (<0,1 %)
Source: USGS, 2015a (national data from 1991 to 2014; estimates based on maximum sample values at each location).
1. The detection limits range from 0.038 to 0.1 mg/L; the mode is 0.000002 mg/L,
2. The current MCLG is zero. Because of analytical limitations, EPA cannot determine the number of samples that do not
exceed the current MCLG. Consequently, EPA reports the number exceeding the current MCL instead of the MCLG.
Exhibit 4-3. NAWQA Occurrence Data for Alachlor Based on Maximum Sample
Values
PUERTO RICO
> r~
0 50 t~—T—-
Miles
HAWAII
ALASKA
Legend
NAWQA Stations
Alachlor
Nondetect
0 100 200 300 400 * Detect - No Exceedance
1 1——J 1 1 • Detect - Exceeds Current MCL Only (0.002 mg/L)
Miles
• Detect - Exceeds Possible MCLG (0.04 mg/L)
Source: USGS, 2015a
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Occurrence Analysis for Potential Source Waters
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Exhibit 4-4. Summary of Alachlor Occurrence for Raw Water Samples in USDA
Agricultural Marketing Service Pesticide Data Program (2007 - 2013)
Occurrence Result
Number of Samples (% total samples)
Total Samples
2,405 (100%)
Detected quantity1
24(1%)
Exceeds current MCL (0.002 mg/L)
0 (0%)
Exceeds possible MCLG (0.04 mg/L)
0 (0%)
Source: USDA, 2014a; 2014b; 2013; 2012; 2011; 2009; and 2008.
1. Detected quantities range from 1.3 X10 5 mg/L to 7.5 X10 5 mg/L. Detection limits range from 1.0 X10 5 mg/L to 9.8 X10 6
mg/L.
4.3.2 Barium
Exhibit 4-5 provides a comparison of maximum barium concentrations for locations in the
NAWQA database with the current MCLG and possible MCLG values. Exhibit 4-6 presents a
spatial representation of the NAWQA data. These data indicate that less than 1% of the total
sampling locations for this contaminant have maximum concentrations between the current
MCLG and the possible MCLG value. Although barium occurs in detected quantities at most of
the NAWQA sampling locations, less than 0.1% of ground water sampling locations and no
surface water sampling locations in NAWQA report maximum concentrations above the current
MCLG.
Exhibit 4-5. Summary of Barium Occurrence in NAWQA - Number and Percent of
Locations by Location Type
Surface Water
Ground Water
Other
Total
Occurrence Result
Locations
Locations
Locations
Locations
Total locations
523(100%)
6,934 (100%)
9 (100%)
7,466 (100%)
All samples are nondetects1
1 (0.2%)
31 (0.4%)
1 (11.1%)
33 (0.4%)
At least one detection
522 (99.8%)
6,903 (99.6%)
8 (88.9%)
7,433 (99.6%)
Exceeds current MCLG (2.0
mg/L)
0 (0%)
5(0.1%)
0 (0%)
5(0.1%)
Exceeds possible MCLG (6.0
mg/L)
0 (0%)
1 (<0.1 %)
0 (0%)
1 (<0.1 %)
Source: USGS, 2015s (national data from 1991 to 2014; estimates based on maximum sample values at each location).
1. The detection limits range from 0.00001 to 0.185 mg/L; the mode is 0.001 mg/L.
4-5
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 4-6. NAWQA Occurrence Data for Barium Based on Maximum Sample
Values
PUERTO RICO
• <
r ^
0 50
Mites
HAWAII
ALASKA
0 100 200 300 400 Detect - No Exceedance
• Detect - Exceeds Current MCLG Only (2.0 mg/L)
• Detect - Exceeds Possible MCLG (6.0 mg/L)
Legend
NAWQA Stations
Barium
Nondetect
Source: USGS, 2015a
4.3.3 Beryllium
Exhibit 4-7 provides comparisons of maximum beryllium concentrations for locations in the
NAWQA database with the current MCLG and possible MCLG values. Exhibit 4-8 presents a
spatial representation of the NAWQA data. These data indicate that less than 0.1% of NAWQA
locations have maximum concentrations between the current MCLG and the possible MCLG.
4-6
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Occurrence Analysis for Potential Source Waters
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Exhibit 4-7. Summary of Beryllium Occurrence in NAWQA - Number and
Percent of Locations by Location Type
Surface Water
Ground Water
Other
Total
Occurrence Result
Locations
Locations
Locations
Locations
Total locations
487 (100%)
6913(100%)
4 (100%)
7404 (100%)
All samples are nondetects1
465 (95.5%)
5679 (82.1%)
4 (100%)
6148 (83.0%)
At least one detection
22 (4.5%)
1234 (17.9%)
0 (0%)
1256 (17.0%)
Exceeds current MCLG (0,004
mg/L)
2 (0.4%)
8 (0,1%)
0 (0%)
10(0,1%)
Exceeds possible MCLG (0,01
mg/L)
2 (0,4%)
3 (<0.1 %)
0 (0%)
5(0.1%)
Source: USGS, 2015a (national data from 1991 to 2014; estimates based on maximum sample values at each location).
1. The detection limits range from 0.000006 to 0.032 mg/L; the mode is 0.001 mg/L.
Exhibit 4-8. NAWQA Occurrence Data for Beryllium Based on Maximum Sample
Values
PUERTO RICO
0 100 200 300 400
Legend
NAWQA Stations
Beryllium
Nondetect
Detect - No Exceedance
• Detect - Exceeds Current MCLG Only (0.004 mg/L)
• Detect - Exceeds Possible MCLG (0.01 mg/L)
<3 ^ HAWAII
%
ALASKA
Source: USGS, 2015a
4-7
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Occurrence Analysis for Potential Source Waters
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4.3.4 1,1-Dichloroethylene
Exhibit 4-9 provides a comparison of maximum 1,1-dichloroethylene concentrations for
locations in the NAWQA database with the current MCLG and possible MCLG values. Exhibit
4-10 presents a spatial representation of the NAWQA data. These data indicate that less than
0.1% of NAWQA locations have maximum concentrations between the current MCLG and the
higher possible MCLG values.
Exhibit 4-9. Summary of 1,1-Dichloroethylene Occurrence in NAWQA - Number
and Percent of Locations by Location Type
Occurrence Result
Surface Water
Locations
Ground Water
Locations
Other
Locations
Total
Locations
Total locations
262 (100%)
7,523 (100%)
197 (100%)
7,982 (100%)
All samples are nondetects1
254 (96.9%)
7,450 (99.0%)
192 (97.5%)
7,896 (98.9%)
At least one detection
8(3.1%)
73 (1.0%)
5 (2.5%)
86 (1.1%)
Exceeds current MCLG (0.007
mg/L)
1 (0.4%)
1 (<0.1 %)
0 (0%)
2 (<0.1 %)
Exceeds possible MCLG (0.4
mg/L)
0 (0%)
0 (0%)
0 (0%)
0 (0%)
Source: USGS, 2015a (national data from 1991 to 2014; estimates based on maximum sample values at each location).
1. The detection limits range from 0.00002 to 0.1 mg/L; the mode is 0.00004 mg/L.
4-8
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Occurrence Analysis for Potential Source Waters
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Exhibit 4-10. Plot of 1 -1 -Dichloroethylene NAWQA Occurrence Data
PUERTO RICO
-
0 50 ~
1 i i i I
Miles
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Occurrence Analysis for Potential Source Waters
for the Third Six-Year Review of NPDWRs
Exhibit 4-11. Summary of 2,4-D Occurrence in NAWQA - Number and Percent of
Locations by Location Type
Occurrence Result
Surface Water
Locations
Ground Water
Locations
Other
Locations
Total
Locations
Total locations
1,083(100%)
5,729 (100%)
167 (100%)
6,979 (100%)
All samples are nondetects1
774 (71.5%)
5,707 (99.6%)
157 (94,0%)
6,638 (95.1%)
At least one detection
309 (28.5%)
22 (0,4%)
10 (6.0%)
341 (4,9%)
Exceeds current MCLG (0,07
mg/L)
1 (0.1%)
0 (0%)
0 (0%)
1 (<0.1 %)
Exceeds possible MCLG (2
mg/L)
0 (0%)
0 (0%)
0 (0%)
0 (0%)
Source: USGS, 2015a (national data from 1991 to 2014; estimates based on maximum sample values at each location).
1. The detection limits range from 0.000013 to 0.00083 mg/L; the mode is 0.000035 mg/L.
Exhibit 4-12. Plot of 2,4-D NAWQA Occurrence Data
- %
m
HAWAII
Legend
ALASKA
NAWQA Stations
2,4-D
Nondetect
PUERTO RICO
Detect - No Exceedance
0 100 200 300 400
Detect - Exceeds Current MCLG Only (0.07 mg/L)
Detect - Exceeds Possible MCLG (2.0 mg/L)
Miles
Source: USGS, 2015a
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Occurrence Analysis for Potential Source Waters
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Exhibit 4-13. Summary of 2,4-D Occurrence for Raw Water Samples in USDA
Agricultural Marketing Service Pesticide Data Program (2007 - 2013)
Occurrence Result
Number of Samples (% total samples)
Total Samples
2,400 (100%)
Detected quantity1
1467 6(1%)
Exceeds current MCLG (0.07 mg/L)
0 (0%)
Exceeds possible MCLG (2 mg/L)
0 (0%)
Source: USDA, 2014a; 2014b; 2013; 2012; 2011; 2009; and 2008.
1. Detected quantities range from 0.004 mg/L to 1.0 X10 6 mg/L. Detection limits range from 9.0 X10 5 mg/L to7.0 X10 7 mg/L.
4.3.6 Diquat
Water quality results for diquat were not available in NAWQA. To characterize potential source
water occurrence, EPA obtained pesticide application estimates because the primary uses of
diquat are as an algaecide, defoliant, desiccant, and herbicide (USEPA, 1995a).
As Exhibit 3-26 and Exhibit 3-27 show, the annual diquat application to crops is generally about
0.2 million pounds. These estimates do not include non-agricultural applications, however.
Pesticide application data from California indicate the potential for crop usage estimates to
understate total diquat use. The State maintains a comprehensive pesticide use reporting
database. Exhibit 4-14 provides a summary of detailed pesticide application estimates for 2012.
Major non-crop used include right-of-way (49,773 pounds), landscape maintenance (14,411
pounds), and water plant treatment (4,160 pounds). The top crop uses were alfalfa (16,796
pounds) and potatoes (5,098 pounds). Total diquat use is almost four times higher than reported
crop use.
Exhibit 4-14. Crop and Noncrop Diquat Application for California in 2012
Use1
Pounds
Percent of Total
Crop Application
23,970
27%
Non Crop Application
64,864
73%
Total Application
88,834
100%
Source: California Department of Pesticide Regulation, 2013.
1. Crop total comprises the following use categories: alfalfa, almonds, figs, grapes, olive, peach, pistachio, pomegranate, potato,
strawberry, tangerine, and uncultivated agriculture. Non-crop total includes all other use categories.
Of the pesticides addressed in this document, only lindane has lower national usage rates than
diquat. Exhibit 4-15 provides national crop use estimates for diquat and the other pesticides
included in this report that were developed by USGS. These data suggest that even if the actual
national use of diquat is several times greater than the crop use estimate indicates, the usage rate
for diquat would be one of the lowest in terms of pounds applied.
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Exhibit 4-15. National Pesticide Use for Crops (2000 to 2009, pounds)
Pesticide
Low
High
2,4-D
297,373,764
326,500,950
Alachlor
45,414,057
91,001,139
Diquat
1,939,863
2,157,264
Lindane
109,614
259,637
Picloram
13,591,501
17,472,227
Source: Thelin and Stone, 2013
USEPA (1995a) notes that although diquat is persistent (i.e., it does not hydrolyze and is
resistant to degradation), it becomes immobile when it adsorbs to soil particles and, therefore, is
unlikely to contaminate ground water. Furthermore, diquat dissipates quickly from surface water
because it adsorbs to soil sediments, vegetation, and organic matter; the estimated half-life in
surface water is 1 to 2 days, based on a study of two ponds in Florida (USEPA, 1995a). These
factors indicate the possibility of low occurrence in drinking water sources.
4.3.7 Lindane
Exhibit 4-16 provides a comparison of maximum lindane concentrations for locations in the
NAWQA database with the current MCLG and the possible MCLG value. Exhibit 4-17 presents
a spatial representation of the NAWQA data. These data indicate that less than 0.1% of NAWQA
locations have maximum concentrations between the current MCLG and the higher possible
MCLG value. Exhibit 4-18 shows lindane raw water concentrations from the PDP database.
Data from both sources indicate almost no occurrence of this contaminant above the current
MCLG and no occurrence above the higher possible MCLG value.
Exhibit 4-16. Summary of Lindane Occurrence in NAWQA - Number and Percent
of Locations by Location Type
Surface Water
Ground Water
Other
Total
Occurrence Result
Locations
Locations
Locations
Locations
Total locations
1994(100%)
6766 (100%)
6 (100%)
8766 (100%)
All samples are nondetects1
1891 (94.8%)
6758 (99.9%)
6 (100%)
8655 (98.7%)
At least one detection
103 (5.2%)
8(0.1%)
0 (0%)
111 (1.3%)
Exceeds current MCLG
(0.0002 mg/L)
1 (0.1%)
0 (0%)
0 (0%)
1 (<0.1 %)
Exceeds possible MCLG (0.03
0 (0%)
0 (0%)
0 (0%)
0 (0%)
mg/L)
Source: USGS, 2015a (national data from 1991 to 2014; estimates based on maximum sample values at each location).
1. The detection limits range from 0.000001 to 0.0939 mg/L; the mode is 0.000004 mg/L.
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Exhibit 4-17. Plot of Lindane NAWQA Occurrence Data
HAWAII
100
Legend
ALASKA
NAWQA Stations
Lindane
Nondetect
PUERTO RICO
Detect - No Exceedance
0 100 200 300 400
• Detect - Exceeds Current MCLG Only (0.0002 mg/L)
• Detect - Exceeds Possible MCLG (0.03 mg/L)
Miles
Source: USGS, 2015a
Exhibit 4-18. Summary of Lindane Occurrence for Raw Water Samples in LISDA
Agricultural Marketing Service Pesticide Data Program (2007 - 2013)
Occurrence Result
Number of Samples (% total samples)
Total Samples
1,881 (100%)
Detected quantity1
3 (0%)
Exceeds current MCL (0.0002 mg/L)
0 (0%)
Exceeds possible MCLG (0.03 mg/L)
0 (0%)
Source: USDA, 2014a; 2014b; 2013; 2012; 2011; 2009; and 2008.
1. Detected quantities range from 1.0 X 10~4 mg/L to 3.3 X10"5 mg/L. Detection limits range from 1.0 X10"5 mg/L to 2.0 X10"5
mg/L.
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4.3.8 Picloram
Exhibit 4-19 provides a comparison of maximum picloram concentrations for locations in the
NAWQA database with the current MCLG and possible MCLG values. Exhibit 4-20 presents a
spatial representation of the NAWQA data. Exhibit 4-21 shows picloram raw water
concentrations from the PDP database. Data from both sources indicate no occurrence of this
contaminant above the current MCLG and the higher possible MCLG values.
Exhibit 4-19. Summary of Picloram Occurrence in NAWQA - Number and Percent
of Locations by Location Type
Occurrence Result
Surface Water
Locations
Ground Water
Locations
Other
Locations
Total
Locations
Total locations
1081 (100%)
5790 (100%)
174 (100%)
7045 (100%)
All samples are nondetects1
1065 (98.5%)
5777 (99.8%)
174 (100%)
7016 (99.6%)
At least one detection
16(1.5%)
13 (0.2%)
0 (0%)
29 (0.4%)
Exceeds current MCLG (0.5
mg/L)
0 (0%)
0 (0%)
0 (0%)
0 (0%)
Exceeds possible MCLG (1.0
mg/L)
0 (0%)
0 (0%)
0 (0%)
0 (0%)
Source: USGS, 2015a (national data from 1991 to 2014; estimates based on maximum sample values at each location).
1. The detection limits range from 0.0000198 to 0.00073 mg/L; the mode is 0.00005 mg/L.
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Exhibit 4-20. Plot of Picloram NAWQA Occurrence Data
PUERTO RICO
0 50
I I I I I
Miles
<3 HAWAII
ALASKA
Legend
NAWQA Stations
Picloram
Nondetect
100 200 300 400 Detect - No Exceedance
J • Detect - Exceeds Current MCLG Only (0.5 mg/L)
Miles
• Detect - Exceeds Possible MCLG (1.0 mg/L)
Source: USGS, 2015a
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Exhibit 4-21. Summary of Picloram Occurrence for Raw Water Samples in USDA
Agricultural Marketing Service Pesticide Data Program (2007 - 2013)
Occurrence Result
Number of Samples (% total samples)
Total Samples
2,407 (100%)
Detected quantity1
25(1%)
Exceeds current MCLG (0.5 mg/L)
0 (0%)
Exceeds possible MCLG (1.0 mg/L)
0 (0%)
Source: USDA, 2014a; 2014b; 2013; 2012; 2011; 2009; and 2008.
1. Detected quantities range from 3.0 X10 4 mg/L to 2.0 X10 5 mg/L. Detection limits range from 4.0 X10 4 mg/L to1.0 X10 5
mg/L.
4.3.9 1,1,1-Trichloroethane
Exhibit 4-22 provides a comparison of maximum 1,1,1-trichloroethane concentrations for
locations in the NAWQA database with the current MCLG and possible MCLG values. Exhibit
4-23 presents a spatial representation of the NAWQA data. The NAWQA data indicate that none
of the sampling locations for this contaminant have maximum concentrations between the
current MCLG and the possible MCLG values.
Exhibit 4-22. Summary of 1,1,1-Trichloroethane Occurrence in NAWQA - Number
and Percent of Locations by Location Type
Occurrence Result
Surface Water
Locations
Ground Water
Locations
Other
Locations
Total
Locations
Total locations
261 (100%)
7,522 (100%)
197 (100%)
7,980 (100%)
All samples are nondetects1
247 (94.6%)
7,350 (97.7%)
194 (98.5%)
7,791 (97.6%)
At least one detection
14(5.4%)
172 (2.3%)
3(1.5%)
189 (2.4%)
Exceeds current MCLG (0.2
mg/L)
0 (0%)
0 (0%)
0 (0%)
0 (0%)
Exceeds possible MCLG (14
mg/L)
0 (0%)
0 (0%)
0 (0%)
0 (0%)
Source: USGS, 2015a (national data from 1991 to 2014; estimates based on maximum sample values at each location).
1. The detection limits range from 0.00002 to 0.1 mg/L; the mode is 0.000032 mg/L.
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Exhibit 4-23. Plot of 1,1,1-Trichloroethane NAWQA Occurrence Data
HAWAII
Legend
ALASKA
NAWQA Stations
1,1,1-Trichloroethane
Nondetect
PUERTO RICO
Detect - No Exceedance
0 100 200 300 400
Detect - Exceeds Current MCLG Only (0.2 mg/L)
Detect - Exceeds Possible MCLG (14 mg/L)
Miles
Source: USGS, 2015a
4.3.10 1,2,4-T richlorobenzene
Exhibit 4-24 provides a comparison of maximum 1,2,4-trichlorobenzene concentrations for
locations in the NAWQA database with the current MCLG and possible MCLG values. Exhibit
4-25 presents a spatial representation of the NAWQA data. The NAWQA data indicate that none
of the sampling locations for this contaminant have maximum concentrations between the
current MCLG and the possible MCLG values.
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Exhibit 4-24. Summary of 1,2,4-Trichlorobenzene Occurrence in NAWQA -
Number and Percent of Locations by Location Type
Surface Water
Ground Water
Other
Total
Occurrence Result
Locations
Locations
Locations
Locations
Total locations
253 (100.0%)
7558 (100,0%)
197 (100.0%)
8008 (100.0%)
All samples are nondetects1
252 (99.6%)
7557 (100.0%)
197(100.0%)
8006 (100.0%)
At least one detection
1 (0.4%)
1 (0,0%]_
0 (0.0%)
2 (0,0%)
Maximum concentration
exceeds current MCL (0.07
mg/L)
0 (0.0%)
0 (0.0%)
0 (0.0%)
0 (0.0%)
Maximum concentration
exceeds possible MCLG (0.7
mg/L)
0 (0.0%)
0 (0.0%)
0 (0.0%)
0 (0.0%)
Source: USGS, 2015a (national data from 1991 to 2014; estimates based on maximum sample values at each location).
1. The detection limits range from 0.04 to 12,0 mg/L; the mode is 0.12 mg/L.
Exhibit 4-25. Plot of 1,2,4-Trichlorobenzene NAWQA Occurrence Data
PUERTO RICO
I i i i l
Miles
<3 HAWAII
Legend
NAWQA Stations
1,2,4-Trichlorobenzene
Nondetect
0 100 200 300 400 * Detect - No Exceedance
1 1——J 1 1 • Detect - Exceeds Current MCLG Only (0.07 mg/L)
Miles
• Detect - Exceeds Possible MCLG (0.7 mg/L)
Source: USGS, 2015a
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5. Conclusions
In its third Six-Year Review, EPA identified the potential to increase the MCLG for several
contaminants based on new health effects information. A possible MCLG increase and
accompanying MCL increase raises the possibility of cost savings to systems treating for the
contaminant. The potential for cost savings from possible MCL increases is system-specific and
depends on various factors including the magnitude of the MCL increase, the concentration of a
contaminant in source water, the specific treatment technology in use, and the extent to which
co-occurring contaminants can affect decisions to change treatment operation. Exhibit 5-1 and
Exhibit 5-2 present a summary of this information.
Exhibit 5-1. Summary of Potential for Cost Savings Based on Source Water
Concentrations
NAWQA -
NAWQA -
PDP-
PDP-
Magnitude
Exceed the
Exceed the
Exceed the
Exceed the
of MCLG
Current
Possible
Current
Possible
Contaminant
Increase1
MCLG
MCLG
MCLG
MCLG
Alachlor
20
0.3%
<0.1%
0%
0%
Barium
3
0.1%
<0.1%
-
-
Beryllium
2.5
0.1%
0.1%
-
-
1,1 -Dichloroethylene
57
<0.1%
0%
-
-
2,4-D
29
<0.1%
0%
0%
0%
Diquat
2
-
-
-
-
Lindane
150
<0.1%
0%
0%
0%
Picloram
2
0%
0%
0%
0%
1,1,1 -T richloroethane
70
0%
0%
-
-
1,2,4-T richlorobenzene
10
0%
0%
-
-
No data were available.
1. Number indicates ratio of the possible MCLG to the current MCL. For example the ratio of the possible MCLG for
alachlor (0.04 mg/L) to the current MCL (0.002 mg/L) is 20, indicating that the possible MCLG is 20 times higher than the
current MCLG.
The new health effects information results in a wide range of possible MCL increases (see
Exhibit 5-1). The lowest relative increase is 2 times the current MCL for both diquat and
picloram. The highest relative increase is 150 times the current MCL for the possible MCLG for
lindane.
EPA's analysis of the potential for cost savings was constrained to readily available data. The
data available to characterize contaminant occurrence was especially limited because there is no
comprehensive dataset that characterizes source water quality for drinking water systems. The
TRI release data indicate relatively widespread releases for barium, beryllium, and 1,1-
dichloroethylene, but sparse releases of the other contaminants. The USGS pesticide use maps
show widespread applications of 2,4-D and picloram, more limited applications of alachlor and
diquat, and no application of lindane since 2011. Despite these environmental release patterns,
water quality data from the NAWQA Program and PDP indicate minimal occurrence above
current MCLG or MCL values. EPA notes that these monitoring datasets are not based on
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random or representative sampling events. Furthermore, the datasets include samples from water
resources that are not drinking water sources. Therefore, these datasets cannot be used directly to
derive quantitative estimates of national occurrence in drinking water sources.
Exhibit 5-2. Summary of Potential for Cost Savings Based on Treatment
Technology
Cost Savings
Co-occurring
Contaminants Limit
Contaminant
Best Available Technology
Potential
Savings?
Alachlor
Granular Activated Carbon
High
Yes
Ion Exchange
High
Yes
Barium
Lime Softening
Moderate
Yes
Reverse Osmosis
Low
Yes
Electrodialysis
Low
Yes
Activated Alumina
High
Yes
Coagulation Filtration
Moderate
Yes
Beryllium
Ion Exchange
High
Yes
Lime Softening
Moderate
Yes
Reverse Osmosis
Low
Yes
1,1 -Dichloroethylene
Packed Tower Aeration
Low
Yes
Granular Activated Carbon
High
Yes
2,4-D
Granular Activated Carbon
High
Yes
Diquat
Granular Activated Carbon
High
Yes
Lindane
Granular Activated Carbon
High
Yes
Picloram
Granular Activated Carbon
High
Yes
1,1,1 -T richloroethane
Packed Tower Aeration
Low
Yes
Granular Activated Carbon
High
Yes
1,2,4-
Packed Tower Aeration
Low
Yes
Trichlorobenzene
Granular Activated Carbon
High
Yes
Nevertheless, the summary of the available data in Exhibit 5-1 shows relatively infrequent
contaminant occurrence in potential source waters at the levels of interest. The NAWQA data
indicate that alachlor, barium, beryllium, 1,1-dichlorethylene, 2,4-D, and lindane occur in
concentrations that exceed current MCLG values. Only alachlor, barium, and beryllium occur in
concentrations that exceed the possible MCLG values, and these exceedances are rare. Three
contaminants - picloram, 1,1,1-trichlorethane, and 1,2,4-trichlorobenzene - are not found at
levels above either the current MCLG or the possible MCLG. Diquat, which is not included in
the either the NAWQA or PDP datasets, may occur infrequently in source water given less
frequent use compared to the other pesticides in the table based on usage patterns (alachlor,
lindane, and picloram) and the tendency of diquat to dissipate quickly from surface water and be
immobile in soils.
As Exhibit 5-2 shows, there is higher potential for operational cost savings for some BAT;
however, co-occurrence considerations for all BAT could diminish the potential to alter
treatment for possible higher MCLGs. Without national estimates of contaminant occurrence in
drinking water sources, EPA cannot determine how many systems currently treat for the
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contaminants listed in Exhibit 5-2. EPA also does not have national data regarding the treatment
technologies being utilized by drinking water systems to control these contaminants.
Despite the possibility for changes in MCLG values that range from 2 to 150 times higher than
current MCLs, the available occurrence data for potential drinking water sources indicate
relatively low contaminant occurrence in the concentration ranges of interest. As a consequence,
EPA cannot conclude that there is a meaningful opportunity for system cost savings.
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6. References
Agency for Toxic Substances & Disease Registry (ATSDR). 2002. Toxicological Profile for
Beryllium. Online at: http://www.atsdr.cdc.gov/ToxProfiles/tp4.pdf.
ATSDR. 2006. Toxicological Profile for 1,1,1-Trichloroethane. Online at:
http://www.atsdr.cdc.gov/toxprofiles/tp70.pdf.
ATSDR. 2007. Toxicological Profile for Barium and Barium Compounds. Online at:
http://www.atsdr.cdc.gov/toxprofiles/tp24.pdf.
ATSDR. 2014. Toxicological Profile for Trichlorobenzenes. Online at:
http://www.atsdr.cdc.gov/toxprofiles/tpl99.pdf.
Baker, N.T., and Stone, W.W., 2015, Estimated annual agricultural pesticide use for counties of
the conterminous United States, 2008-12: U.S. Geological Survey Data Series 907, 9 p.
California Department of Pesticide Regulation, 2013. Summary of Pesticide Use Report Data
2012: Indexed by Chemical. Online http://www.cdpr.ca.gov/docs/pur/purl2rep/chmrptl2.pdf.
Gilliom, R.J., J.E. Barbash, C. G. Crawford, P.A. Hamilton, J.D. Martin, N. Nakagaki, L.H.
Nowell, J.C. Scott, P.E. Stackelberg, G.P. Thelin, and D.M. Wolock. 2006. The Quality of Our
Nation's Waters—Pesticides in the Nation's Streams and Ground Water, 1992-2001: U.S.
Geological Survey Circular 1291. Reston, VA: U.S. Department of the Interior, U.S. Geological
Survey.
Thelin, G.P., and Stone, W.W. 2013. Estimation of Annual Agricultural Pesticide Use for
Counties of the Conterminous United States, 1992-2009. U.S. Geological Survey Scientific
Investigations Report 2013-5009, 54 p.
U.S. Department of Agriculture (USD A). 2008. Pesticide Data Program: Annual Summary,
Calendar Year 2007. Washington, D.C.: USD A, Agricultural Marketing Service, Science and
Technology Program.
USDA. 2009. Pesticide Data Program: Annual Summary, Calendar Year 2008. Washington,
D.C.: USDA, Agricultural Marketing Service, Science and Technology Program.
USDA. 2011. Pesticide Data Program: Annual Summary, Calendar Year 2009. Washington,
D.C.: USDA, Agricultural Marketing Service, Science and Technology Program.
USDA. 2012. Pesticide Data Program: Annual Summary, Calendar Year 2010. Washington,
D.C.: USDA, Agricultural Marketing Service, Science and Technology Program.
USDA. 2013. Pesticide Data Program: Annual Summary, Calendar Year 2011. Washington,
D.C.: USDA, Agricultural Marketing Service, Science and Technology Program.
USDA. 2014a. Pesticide Data Program: Annual Summary, Calendar Year 2013. Washington,
D.C.: USDA, Agricultural Marketing Service, Science and Technology Program.
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USDA. 2014b. Pesticide Data Program: Annual Summary, Calendar Year 2012. Washington,
D.C.: USDA, Agricultural Marketing Service, Science and Technology Program.
U.S. Environmental Protection Agency (USEPA). 1995a. Reregi strati on Eligibility Decision
(RED) Diquat Dibromide. EPA 738-R-05-016. Online at:
http://archive.epa.gov/pesticides/reregistration/web/pdf/0288.
USEPA. 1995b. Reregi strati on Eligibility Decision (RED) Picloram. Online at:
http://archive.epa.gov/pesticides/reregistration/web/pdf/0096.pdf.
USEPA. 1998a. R E D. Facts: Alachlor. EPA 738-F-98-018. Online at:
https://www3.epa.gOv/pesticides/chem_search/reg_actions/reregistration/fs_PC-090501_l-Dec-
98.pdf.
USEPA. 1998b. Small System compliance Technology List for the Non-Microbial contaminants
Regulated Before 1996. EPA Report 815-R-98-002. Washington, D.C.: USEPA Office of Water.
USEPA. 2002. 1,1 -Dichloroethylene (1,1-DCE); CASRN 75-35-4. Online at:
http://cfpub.epa.gov/ncea/iris/iris_documents/documents/subst/0039_summary.pdf.
USEPA. 2003. EPA Protocol for Review of Existing National Primary Drinking Water
Regulations. EPA 815-R-03-002.
USEPA. 2005. Reregi strati on Eligibility Decision for 2,4-D. EPA 738-R-05-002. Online at:
https://archive.epa.gov/pesticides/reregistration/web/pdf/24d_red.pdf.
USEPA. 2006. Addendum to the July 2002 Lindane Reregi strati on Eligibility Decision. Online
at: https://archive.epa.gov/pesticides/reregistration/web/pdf/lindane_red_addendum.pdf.
USEPA. 2007. Toxicological Review of 1,1,1-Trichloroethane. Online at:
https://cfpub.epa.gov/ncea/iris/iris_documents/documents/toxreviews/0197tr.pdf.
USEPA. 2009. EPA Protocol for the Second Review of Existing National Primary Drinking
Water Regulations (Updated). EPA 815-B-09-002.
USEPA. 2015. TRI Explorer. 2013 National Analysis dataset (released October 2014) (Updated
Nov 24, 2014)) [Internet database]. Online at: http://www.epa.gov/triexplorer, accessed February
05, 2015.
USEPA. 2016a. The Analysis of Regulated Contaminant Occurrence Data from Public Water
Systems in Support of the Third Six-Year Review of National Primary Drinking Water
Regulations: Chemical Phase Rules and Radionuclides Rules. EPA 810-R-16-014.
USEPA. 2016b. Analytical Feasibility Support Document for the Third Six-Year Review of
National Primary Drinking Water Regulations: Chemical Phase Rules and Radionuclides Rules.
EPA 810-R-16-005
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USEPA. 2016c. Six-Year Review 3 - Health Effects Assessment for Existing Chemical and
Radionuclide National Primary Drinking Water Regulations - Summary Report EPA 833-R-16-
008.
U.S. Geological Survey (USGS). 2006a. About NAWQA Study Units. December. Online at:
http ://water.usgs.gov/nawqa/ studies/study_units.html.
USGS. 2006b. National Water Quality Assessment (NAWQA) Program. Online at
http://infotrek.er.usgs.gov, accessed 8/28/06.
USGS.2015a. National Water Quality Assessment (NAWQA) Program. Online at
http://infotrek.er.usgs.gov, accessed 1/30/15.
USGS. 2015b. Pesticide National Synthesis Project. Online at
http://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php, accessed 3/20/2015.
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