United States
Environmental Protection
Agency
Analytical Feasibility Support Document for the Second Six-Year Review of
Existing National Primary Drinking Water Regulations
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Office of Water (4607M)
EPA815-B-09-003
October 2009
www. epa. gov/safewater
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Acknowledgments
Thanks to Mr. Shawn Kassner and Dr. Mark Carter (formerly) of Environmental
Resource Associates (ERA; now ERA - A Waters Company) for sharing their expertise and their
PT data.
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
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Executive Summary
The Safe Drinking Water Act (SDWA), as amended in 1996, requires the Environmental
Protection Agency (EPA) to review and revise, if appropriate, existing National Primary
Drinking Water Regulations (NPDWRs). Review involves consideration of five key elements,
as appropriate: health effects, analytical and treatment feasibility, implementation-related issues,
occurrence and exposure, and economic impact. This report addresses the analytical feasibility
aspect of the review which has been based on the laboratories' analytical performance data
generated as part of the EPA's certification program for drinking water laboratories. This
analytical feasibility assessment is based jointly on the recent analytical performance data
collected during the second six year review as well as on earlier data collected during the first six
year review. Efforts are also made to determine if the analytical performance assessments based
on the laboratory data are supported by the approval of improved methods or revision of existing
methods since the last review. The goal is to create a comprehensive document that addresses all
regulated chemical analytes for which data are available.
Analytical Performance Assessment Based on the Laboratories' Analytical Performance Data
The Practical Quantitation Level (PQL) assessments are presented by way of linear
regressions that plot laboratory passing rate versus true concentration. The PQL is defined as
"the lowest achievable level of analytical quantitation during routine laboratory operating
conditions within specified limits of precision and accuracy" (50 FR 46902, November 13,
1985). It has been set at the concentration where 75% of laboratories are predicted to meet
acceptance criteria. PQL determination can be a useful tool in assessing whether promulgated
PQLs can be reduced as a result of improved laboratory performance over time.
The Six-Year 1 laboratory passing rate data were generated during the EPA-administered
Performance Evaluation (PE) Program from the late 1980s through late 1999, at which time, the
laboratory performance program became privatized under the direction of the National
Environmental Laboratory Accreditation Conference (NELAC; now The NELAC Institute -
TNI). The current report includes PQL assessments for all available Six-Year 1 PE data and
more recent laboratory passing rate data that were generated under the TNI Proficiency Testing
(PT) program. Environmental Resource Associates (ERA) was the only provider of PT samples
to the testing laboratories that was willing to share PT data with EPA. ERA estimates that during
the period from late 1999 through 2006, they have accounted for approximately 50% of all PT
results nationwide.
For non-radionuclides, the ERA dataset encompasses the period from late 1999 through
2004. ERA data for radionuclides were generated from 2002-2006. Note that for the
radionuclides, limitations of laboratory performance at low concentrations is generally not an
issue, as PQLs can be lowered, if necessary, by increasing sample volume and/or radiological
analysis duration. Thus, though the radionuclide PT data are evaluated in this report (see
Appendix B) for completeness, no conclusions are drawn regarding changes to PQLs.
The results for the regulated analytes are broken down into two categories based on the
limitation of the PQL for setting the Maximum Contaminant Level (MCL) at the time of
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promulgation: 1) analytes with MCL equal to the current PQL, and thus the PQL is limiting; or
2) analytes with MCL greater than the current PQL and thus it is technically feasible to reduce an
MCL. PQL assessment for this second group of analytes can indicate the potential for MCL
reduction beyond the current PQL. Using this as a framework, the PQL assessments based on
the PT/PE data were made and are presented in this report for a total of 66 analytes. Four
analytes could not be analyzed for the reasons stated: acrylamide, epichlorohydrin, 2,3,7,8-
TCDD (dioxin) lacked PE/PT data, and chlorite has no PQL. The recommendations for PQL
assessment are as follows:
For 25 analytes, the PQL is equal to the MCL and hence the PQL is limiting. Of these 25
analytes, PQL assessment indicates that:
- The PQL can be reduced for 9 analytes: benzene, carbon tetrachloride, chlordane,
1,2-dichloroethane, 1,2-dichloropropane, hexachlorobenzene, tetrachloroethylene,
1,1,2-trichloroethane, and trichloroethylene;
- The PQL might be considered for reduction for 8 analytes: alachlor, antimony, 1,2-
dibromo-3-chloropropane (DBCP), heptachlor, heptachlor epoxide, lindane,
toxaphene, and vinyl chloride; and
- PT data do not support reduction of the PQL or data are inconclusive or insufficient
to reach a conclusion for 8 analytes: benzo(a)pyrene, bromate, dichloromethane,
di(2-ethylhexyl)phthalate (DEHP), ethylene dibromide (EDB), pentachlorophenol,
polychlorinatedbiphenyls (PCBs), and thallium.
For 41 analytes, the PQL is less than the MCL; hence the MCL can be reduced. For these
41 analytes, PQL assessment indicates that:
- The PQL can be reduced further (beyond the current PQL) for 11 analytes: barium,
1,4-dichlorobenzene, c/5-l,2-dichloroethylene, 1,1-dichloroethylene, ethylbenzene,
monochlorobenzene, nitrite, styrene, toluene, 1,2,4-trichlorobenzene, and 1,1,1-
trichloroethane;
- The PQL might be considered for further reduction for 6 analytes: atrazine,
carbofuran, rram--l,2-dichloroethylene, hexachlorocyclopentadiene, methoxychlor,
and 2,4,5-TP (Silvex); and
- PE/PT data do not support further reduction of the PQL or data are inconclusive or
insufficient to reach a conclusion for 24 analytes: arsenic, beryllium, cadmium,
chromium, copper, cyanide, dalapon, 1,2-dichlorobenzene, 2,4-dichlorophenoxyacetic
acid (2,4-D), di(2-ethylhexyl)adipate, dinoseb, diquat, endothall, endrin, fluoride,
glyphosate, lead, mercury, nitrate, oxamyl, picloram, selenium, simazine, and
xylenes.
Analytical Performance Assessment Based on New Methods Approval/Revision of Existing
Methods
For those analytes with new methods, improved analytical performance (and hence,
possible reduction of the PQL) may be suggested by lower detection limits from new methods.
The existence of new methods with lower detection limits may not directly translate to improved
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analytical performance, however. It is possible that only a small number of laboratories will use
a new method, or it may take time for the method to be utilized to its full effectiveness.
Improved analytical performance (and hence, possible PQL reduction) may also be
supported by the approval and availability of new or revised analytical methods with lower
MDLs (note that in some analytical methods, the term DL is used instead of MDL, but these
quantities are essentially equivalent). For 15 regulated analytes, new methods have been
approved. For 12 of these analytes (bromate, carbofuran, 2,4-D, dalapon, dinoseb, fluoride,
mercury, nitrite, oxamyl, pentachlorophenol, picloram and 2,4,5-TP), the MDLs are lower (or
their range of MDLs includes values that are lower) than those from earlier-approved methods.
In two cases (atrazine and cyanide), the methods are proprietary and are not readily available;
hence, MDLs are not known, and comparison cannot be made. Lastly, in one case (nitrate), new
or revised methods do not indicate a lower MDL.
Overall, the results show that only for 20 of the 66 analytes evaluated in this report,
laboratory performance data was sufficient to qualitatively conclude that the PQL can be
lowered. For 14 analytes there were indications for a lower PQL but for the remaining 32 either
the data were inconclusive or insufficient to draw a conclusion. Furthermore, for only 3 of the
20 analytes for which PQL could be lowered, the improved analytical performance was
supported by new and improved methods approval. For others, there was either no correlation or
correlation could not be made due to insufficient data.
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Abbreviations and Acronyms
mg/L
Der.
ACVT
AES
APG
ASTM
CASRN
CBI
CCGC
CUV
CVAAS
CVAFS
CFR
2,4-D
DAI
DBCP
DCBP
DEHA
DEHP
DL
BCD
ECGC
EDB
ELCD
EPA
ERA
FD
FR
GC
GFAA
HPLC
1C
ICP
ICR
I-EE
I-ELSE
IMDL
LLE
LLED
LLMED
L/S
LSE
Micrograms per liter
Milligrams per liter
Derivatization
Automated Cold Vapor Technique
Atomic Emission Spectrometry
Analytical Products Group, Inc.
American Society for Testing and Materials
Chemical Abstracts Service Registry Number
Confidential Business Information
Capillary Column Gas Chromatography
Coupled Ultraviolet
Cold Vapor Atomic Absorption Spectrometry
Cold Vapor Atomic Fluorescence Spectrometry
Code of Federal Regulations
2,4-Dichlorphenoxyacetic acid
Direct Aqueous Injection
l,2-Dibromo-3-chloropropane
Decachlorobiphenyl
Di(2-ethylhexyl)adipate
Di(2-ethylhexyl)phthalate
Detection Limit
Electron Capture Detection
Electron Capture Gas Chromatography
Ethylene Dibromide (1,2-dibromoethane)
Electrolytic Conductivity Detector
United States Environmental Protection Agency
Environmental Resource Associates (name changed to ERA - A
Waters Company, effective July 10, 2009)
Fluorescence Detection
Federal Register
Gas Chromatography
Graphite Furnace Atomic Absorption
High Performance Liquid Chromatography
Ion Chromatography
Inductively Coupled Plasma
Information Collection Request
Ion-Exchange Extraction
Ion-Exchange Liquid/Solid Extraction
Interlaboratory Method Detection Limit
Liquid/Liquid Extraction
Liquid/Liquid Extraction and Derivatization
Liquid/Liquid Microextraction and Derivatization
Liquid/Solid
Liquid/Solid Extraction
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MCL
MCLG
MDL
ME
ML
MLPD
MRL
MS
NDWAC
NELAC
NERL
N-PD
NPDWR
OLS
PCB
PDAUVD
PE
PID
PQL
PT
QA
QC
RDL
SD
SDWA
TNI
TT
2,4,5-TP
u.s.c.
USEPA
UVD
VOC
Maximum Contaminant Level
Maximum Contaminant Level Goal
Method Detection Limit
Microextraction
Minimum Level
Multi-Laboratory Performance Data
Minimum Reporting Level
Mass Spectrometry
National Drinking Water Advisory Council
National Environmental Laboratory Accreditation Conference
National Exposure Research Laboratory
Nitrogen-Phosphorus Detector
National Primary Drinking Water Regulation
Ordinary Least Squares
Polychlorinatedbiphenyl
Photodiode Array Ultraviolet Detector
Performance Evaluation
Photoionization Detector
Practical Quantitation Level
Proficiency Testing
Quality Assurance
Quality Control
Regulatory Detection Limit
Standard Deviation(s)
Safe Drinking Water Act
The NELAC Institute
Treatment Technique
2-(2,4,5-Trichlorophenoxy)propionic acid
United States Code
United States Environmental Protection Agency
Ultraviolet Detection
Volatile Organic Compound
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TABLE OF CONTENTS
Acknowledgments i
Executive Summary ii
Abbreviations and Acronyms v
1.0 Introduction 1
2.0 Background 2
2.1 RELATIONSHIP BETWEEN SDWA REQUIREMENTS AND ANALYTICAL METHODS 2
2.2 PQL DETERMINATION METHODS FOR THE SDWA CONTAMINANTS 3
2.3 OPERATIONAL DETAILS OF THE PE/PT PROGRAMS 6
2.4 EFFORTS MADE TO OBTAIN PT DATA 8
3.0 Representativeness of Available PT Data 8
3.1 BIAS 9
3.2 PRECISION 9
3.3 THE REGRESSION MODEL 10
4.0 Identification of Regulated Analytes for PQL Assessment 11
5.0 Second Six-Year Review PQL Assessment Methodology 15
5.1 DATA AVAILABLE FOR PQL ASSESSMENT 15
5.2 CALCULATING NATIONAL PASSING RATES 19
5.3 REGRESSION PLOTS 20
6.0 Results of PQL Assessment 21
6.1 ANALYTES WITH MAXIMUM CONTAMINANT LEVEL (MCL) EQUAL TO THE CURRENT PQL AND THUS THE
PQL is LIMITING 22
6.1.1 PQL Assessment Supports Reduction of the Current PQL 22
Benzene 23
Results of the Methods Comparison 23
Results of the PQL Analysis 23
Conclusion for Benzene 24
Carbon Tetrachloride 25
Results of the Methods Comparison 25
Results of the PQL Analysis 25
Conclusion for Carbon Tetrachloride 26
Chlordane 27
Results of the Methods Comparison 27
Results of the PQL Analysis 27
Conclusion for Chlordane 28
1,2-Dichloroethane (Ethylene dichloride) 29
Results of the Methods Comparison 29
Results of the PQL Analysis 29
Conclusion for 1,2-Dichloroethane 30
1,2-Dichloropropane 31
Results of the Methods Comparison 31
Results of the PQL Analysis 31
Conclusion for 1,2-Dichloropropane 32
Hexachlorobenzene 33
Results of the Methods Comparison 33
Results of the PQL Analysis 33
Conclusion for Hexachlorobenzene 34
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Tetrachloroethylene 35
Results of the Methods Comparison 35
Results of the PQL Analysis 35
Conclusion for Tetrachloroethylene 36
1,1,2-Trichloroethane 37
Results of the Methods Comparison 37
Results of the PQL Analysis 37
Conclusion for 1,1,2-Trichloroethane 38
Trichloroethylene 39
Results of the Methods Comparison 39
Results of the PQL Analysis 39
Conclusion for Trichloroethylene 40
6.1.2 PQL Assessment May Support Reduction of the Current PQL 41
Alachlor 41
Results of the Methods Comparison 41
Results of the PQL Analysis 41
Conclusion for Alachlor 42
Antimony 43
Results of the Methods Comparison 43
Results of the PQL Analysis 43
Conclusion for Antimony 44
1,2-Dibromo-3-chloropropane (DBCP) 45
Results of the Methods Comparison 45
Results of the PQL Analysis 45
Conclusion for l,2-Dibromo-3-chloropropane 46
Heptachlor 47
Results of the Methods Comparison 47
Results of the PQL Analysis 47
Conclusion for Heptachlor 48
Heptachlor Epoxide 49
Results of the Methods Comparison 49
Results of the PQL Analysis 49
Conclusion for Heptachlor Epoxide 50
Lindane 51
Results of the Methods Comparison 51
Results of the PQL Analysis 51
Conclusion for Lindane 52
Toxaphene 53
Results of the Methods Comparison 53
Results of the PQL Analysis 53
Conclusion for Toxaphene 54
Vinyl Chloride 55
Results of the Methods Comparison 55
Results of the PQL Analysis 55
Conclusion for Vinyl Chloride 56
6.1.3 PQL Assessment Does Not Support Reduction of the Current PQL or Data are Insufficient to Reach a
Conclusion 57
Benzo(a)pyrene 57
Results of the Methods Comparison 57
Results of the PQL Analysis 57
Conclusion for Benzo(a)pyrene 58
Bromate 59
Results of the Methods Comparison 59
Results of the PQL Analysis 59
Conclusion for Bromate 60
Dichloromethane (Methylene chloride) 61
Results of the Methods Comparison 61
Results of the PQL Analysis 61
Conclusion for Dichloromethane 62
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Di(2-ethylhexyl)phthalate (DEEP) 63
Results of the Methods Comparison 63
Results of the PQL Analysis 63
Conclusion for Di(2-ethylhexyl)phthalate 64
Ethylene dibromide (EDB) 65
Results of the Methods Comparison 65
Results of the PQL Analysis 65
Conclusion for Ethylene Dibromide 66
Pentachlorophenol 67
Results of the Methods Comparison 67
Results of the PQL Analysis 67
Conclusion for Pentachlorophenol 68
Polychlorinatedbiphenyls (PCBs) as Decachlorobiphenyl (DCBP) 69
Results of the Methods Comparison 69
Results of the PQL Analysis 70
Conclusion for Polychlorinatedbiphenyls 70
Thallium 71
Results of the Methods Comparison 71
Results of the PQL Analysis 71
Conclusion for Thallium 72
6.2 ANALYTES WITH MAXIMUM CONTAMINANT LEVEL (MCL) GREATER THAN THE CURRENT PQL AND
THUS IT is TECHNICALLY FEASIBLE TO REDUCE AN MCL 73
6.2.1 PQL Assessment Supports Reduction of the Current PQL 73
Barium 73
Results of the Methods Comparison 73
Results of the PQL Analysis 73
Conclusion for Barium 74
1,4-Dichlorobenzene 75
Results of the Methods Comparison 75
Results of the PQL Analysis 75
Conclusion for 1,4-Dichlorobenzene 76
cis-l,2-Dichloroethylene 77
Results of the Methods Comparison 77
Results of the PQL Analysis 77
Conclusion for cis-1,2-Dichloroethylene 78
1,1-Dichloroethylene 79
Results of the Methods Comparison 79
Results of the PQL Analysis 79
Conclusion for 1,1-Dichloroethylene 80
Ethylbenzene 81
Results of the Methods Comparison 81
Results of the PQL Analysis 81
Conclusion for Ethylbenzene 82
Monochlorobenzene (Chlorobenzene) 83
Results of the Methods Comparison 83
Results of the PQL Analysis 83
Conclusion for Monochlorobenzene 84
Nitrite (asN) 85
Results of the Methods Comparison 85
Results of the PQL Analysis 85
Conclusion for Nitrite 86
Styrene 87
Results of the Methods Comparison 87
Results of the PQL Analysis 87
Conclusion for Styrene 88
Toluene 89
Results of the Methods Comparison 89
Results of the PQL Analysis 89
Conclusion for Toluene 90
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1,2,4-Trichlorobenzene 91
Results of the Methods Comparison 91
Results of the PQL Analysis 91
Conclusion for 1,2,4-Trichlorobenzene 92
1,1,1-Trichloroethane 93
Results of the Methods Comparison 93
Results of the PQL Analysis 93
Conclusion for 1,1,1-Trichloroethane 94
6.2.2 PQL Assessment May Support Reduction of the Current PQL 95
Atrazine 95
Results of the Methods Comparison 95
Results of the PQL Analysis 95
Conclusion for Atrazine 96
Carbofuran 97
Results of the Methods Comparison 97
Results of the PQL Analysis 97
Conclusion for Carbofuran 98
trans-l,2-Dichloroethylene 99
Results of the Methods Comparison 99
Results of the PQL Analysis 99
Conclusion for /rawi-l,2-Dichloroethylene 100
Hexachlorocyclopentadiene 101
Results of the Methods Comparison 101
Results of the PQL Analysis 101
Conclusion for Hexachlorocyclopentadiene 102
Methoxychlor 103
Results of the Methods Comparison 103
Results of the PQL Analysis 103
Conclusion for Methoxychlor 104
2-(2,4,5-Trichlorophenoxy)propanoic acid (2,4,5-TP; Silvex) 105
Results of the Methods Comparison 105
Results of the PQL Analysis 105
Conclusion for 2,4,5-TP 106
6.2.3 PQL Assessment Does Not Support Reduction of the Current PQL or Data are Insufficient to Reach a
Conclusion 707
Arsenic 707
Results of the Methods Comparison 107
Results of the PQL Analysis 107
Conclusion for Arsenic 108
Beryllium 109
Results of the Methods Comparison 109
Results of the PQL Analysis 109
Conclusion for Beryllium 110
Cadmium Ill
Results of the Methods Comparison Ill
Results of the PQL Analysis Ill
Conclusion for Cadmium 112
Chromium 113
Results of the Methods Comparison 113
Results of the PQL Analysis 113
Conclusion for Chromium 114
Copper 115
Results of the Methods Comparison 115
Results of the PQL Analysis 115
Conclusion for Copper 116
Cyanide 117
Results of the Methods Comparison 117
Results of the PQL Analysis 117
Conclusion for Cyanide 118
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Dalapon 119
Results of the Methods Comparison 119
Results of the PQL Analysis 119
Conclusion for Dalapon 120
1,2-Dichlorobenzene 121
Results of the Methods Comparison 121
Results of the PQL Analysis 121
Conclusion for 1,2-Dichlorobenzene 122
2,4-Dichlorophenoxyacetic acid (2,4-D) 123
Results of the Methods Comparison 123
Results of the PQL Analysis 123
Conclusion for 2,4-D 124
Di(2-ethylhexyl)adipate (DEHA) 125
Results of the Methods Comparison 125
Results of the PQL Analysis 125
Conclusion for DEHA 126
Dinoseb 727
Results of the Methods Comparison 127
Results of the PQL Analysis 127
Conclusion for Dinoseb 128
Diquat 129
Results of the Methods Comparison 129
Results of the PQL Analysis 129
Conclusion for Diquat 130
Endothall 131
Results of the Methods Comparison 131
Results of the PQL Analysis 131
Conclusion for Endothall 132
Endrin 133
Results of the Methods Comparison 133
Results of the PQL Analysis 133
Conclusion for Endrin 134
Fluoride 135
Results of the Methods Comparison 135
Results of the PQL Analysis 135
Conclusion for Fluoride 136
Glyphosate 137
Results of the Methods Comparison 137
Results of the PQL Analysis 137
Conclusion for Glyphosate 138
Lead 139
Results of the Methods Comparison 139
Results of the PQL Analysis 139
Conclusion for Lead 140
Mercury 141
Results of the Methods Comparison 141
Results of the PQL Analysis 141
Conclusion for Mercury 142
Nitrate (as N) 143
Results of the Methods Comparison 143
Results of the PQL Analysis 143
Conclusion for Nitrate 144
Oxamyl (Vydate) 145
Results of the Methods Comparison 145
Results of the PQL Analysis 145
Conclusion for Oxamyl 146
Picloram 147
Results of the Methods Comparison 147
Results of the PQL Analysis 147
Conclusion for Picloram 148
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Selenium 149
Results of the Methods Comparison 149
Results of the PQL Analysis 149
Conclusion for Selenium 150
Simazine 151
Results of the Methods Comparison 151
Results of the PQL Analysis 151
Conclusion for Simazine 152
Xylenes (total) 153
Results of the Methods Comparison 153
Results of the PQL Analysis 153
Conclusion for Xylenes 154
7.0 Summary 155
8.0 References 165
Appendix A: Listing of New and Updated Analytical Methods A-l
Appendix B: Radionuclide Regressions B-l
ALPHABETICAL LIST OF ANALYTE PROFILES
1,1,1-Trichloroethane 93
1,1,2-Trichloroethane 37
1,1-Dichloroethylene 79
1,2,4-Trichlorobenzene 91
l,2-Dibromo-3-chloropropane (DBCP 45
1,2-Dichlorobenzene 121
1,2-Dichloroethane (Ethylene 29
1,2-Dichloropropane 31
1,4-Dichlorobenzene 75
2,4,5-TP (Silvex) 105
2,4-Dichlorophenoxyacetic acid (2,4-D) 123
Alachlor 41
Antimony 43
Arsenic 107
Atrazine 95
Barium 73
Benzene 23
Benzo(a)pyrene 57
Beryllium 109
Bromate 59
Cadmium Ill
Carbofuran 97
Carbon Tetrachloride 25
Chlordane 27
Chromium 113
cis-l,2-Dichloroethylene 77
Copper 115
Cyanide 117
Dalapon 119
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Di(2-ethylhexyl)adipate (DEHA) 125
Di(2-ethylhexyl)phthalate (DEHP) 63
Dichloromethane (Methylene chloride) 61
Dinoseb 127
Diquat 129
Endothall 131
Endrin 133
Ethylbenzene 81
Ethylene dibromide (EDB) 65
Fluoride 135
Glyphosate 137
Heptachlor 47
Heptachlor Epoxide 49
Hexachlorobenzene 33
Hexachlorocyclopentadiene 101
Lead 139
Lindane 51
Mercury 141
Methoxychlor 103
Monochlorobenzene (Chlorobenzene) 83
Nitrate (as N) 143
Nitrite (as N) 85
Oxamyl (Vydate) 145
Pentachlorophenol 67
Picloram 147
Polychlorinatedbiphenyls (PCBs) as Decachlorobiphenyl (DCBP) 69
Selenium 149
Simazine 151
Styrene 87
Tetrachloroethylene 35
Thallium 71
Toluene 89
Toxaphene 53
trans-1,2-Dichloroethylene 99
Trichloroethylene 39
Vinyl Chloride 55
Xylenes (total) 153
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LIST OF EXHIBITS
Exhibit 1: Summary of Differences Between EPA's PE Program and NELAC' s PT Program.... 7
Exhibit 2: U.S. EPA National Primary Drinking Water Standards and Related Information 11
Exhibit 3: Availability of Six-Year 1 PE Data and Six-Year 2 PT Data for Regulated Analytes 16
Exhibit 4: Analytical Methods for Benzene 23
Exhibit 5: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Benzene 24
Exhibit 6: Analytical Methods for Carbon Tetrachloride 25
Exhibit 7: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Carbon Tetrachloride 26
Exhibit 8: Analytical Methods for Chlordane 27
Exhibit 9: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Chlordane 28
Exhibit 10: Analytical Methods for 1,2-Dichloroethane 29
Exhibit 11: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,2-Dichloroethane 30
Exhibit 12: Analytical Methods for 1,2-Dichloropropane 31
Exhibit 13: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,2-Dichloropropane 32
Exhibit 14: Analytical Methods for Hexachlorobenzene 33
Exhibit 15: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Hexachlorobenzene 34
Exhibit 16: Analytical Methods for Tetrachloroethylene 35
Exhibit 17: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Tetrachloroethylene 36
Exhibit 18: Analytical Methods for 1,1,2-Trichloroethane 37
Exhibit 19: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,1,2-Trichloroethane... 38
Exhibit 20: Analytical Methods for Trichloroethylene 39
Exhibit 21: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Trichloroethylene 40
Exhibit 22: Analytical Methods for Alachlor 41
Exhibit 23: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Alachlor 42
Exhibit 24: Analytical Methods for Antimony 43
Exhibit 25: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Antimony 44
Exhibit 26: Analytical Methods for DBCP 45
Exhibit 27: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - DBCP 46
Exhibit 28: Analytical Methods for Heptachlor 47
Exhibit 29: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Heptachlor 48
Exhibit 30: Analytical Methods for Heptachlor Epoxide 49
Exhibit 31: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Heptachlor Epoxide 50
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Exhibit 32: Analytical Methods for Lindane 51
Exhibit 33: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Lindane 52
Exhibit 34: Analytical Methods for Toxaphene 53
Exhibit 3 5: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Toxaphene 54
Exhibit 36: Analytical Methods for Vinyl Chloride 55
Exhibit 37: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Vinyl Chloride 56
Exhibit 38: Analytical Methods for Benzo(a)pyrene 57
Exhibit 39: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Benzo(a)pyrene 58
Exhibit 40: Analytical Methods for Bromate 59
Exhibit 41: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Bromate 60
Exhibit 42: Analytical Methods for Dichloromethane 61
Exhibit 43: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Dichloromethane 62
Exhibit 44: Analytical Methods for Di(2-ethylhexyl)phthalate 63
Exhibit 45: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Di(2-ethylhexyl)phthalate
64
Exhibit 46: Analytical Methods for Ethylene Dibromide 65
Exhibit 47: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Ethylene Dibromide 66
Exhibit 48: Analytical Methods for Pentachlorophenol 67
Exhibit 49: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Pentachlorophenol 68
Exhibit 50: Analytical Methods forPCBs: As Decachlorobiphenyl 69
Exhibit 51: Analytical Methods forPCBs: As Aroclors 69
Exhibit 52: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - PCBs 70
Exhibit 53: Analytical Methods for Thallium 71
Exhibit 54: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Thallium 72
Exhibit 55: Analytical Methods for Barium 73
Exhibit 56: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Barium 74
Exhibit 57: Analytical Methods for 1,4-Dichlorobenzene 75
Exhibit 58: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,4-Dichlorobenzene .... 76
Exhibit 59: Analytical Methods for c/5-l,2-Dichloroethylene 77
Exhibit 60: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - c/5-l,2-Dichloroethylene
78
Exhibit 61: Analytical Methods for 1,1-Dichloroethylene 79
Exhibit 62: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data- 1,1-Dichloroethylene.... 80
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Exhibit 63: Analytical Methods for Ethylbenzene 81
Exhibit 64: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Ethylbenzene 82
Exhibit 65: Analytical Methods for Monochlorobenzene 83
Exhibit 66: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Monochlorobenzene 84
Exhibit 67: Analytical Methods for Nitrite (as N) 85
Exhibit 68: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Nitrite 86
Exhibit 69: Analytical Methods for Styrene 87
Exhibit 70: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Styrene 88
Exhibit 71: Analytical Methods for Toluene 89
Exhibit 72: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Toluene 90
Exhibit 73: Analytical Methods for 1,2,4-Trichlorobenzene 91
Exhibit 74: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,2,4-Trichlorobenzene 92
Exhibit 75: Analytical Methods for 1,1,1-Trichloroethane 93
Exhibit 76: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,1,1-Trichloroethane... 94
Exhibit 77: Analytical Methods for Atrazine 95
Exhibit 78: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Atrazine 96
Exhibit 79: Analytical Methods for Carbofuran 97
Exhibit 80: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Carbofuran 98
Exhibit 81: Analytical Methods for ^ram'-l,2-Dichloroethylene 99
Exhibit 82: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - tmns-1,2-
Dichloroethylene 100
Exhibit 83: Analytical Methods for Hexachlorocyclopentadiene 101
Exhibit 84: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data -
Hexachlorocyclopentadiene 102
Exhibit 85: Analytical Methods forMethoxychlor 103
Exhibit 86: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Methoxychlor 104
Exhibit 87: Analytical Methods for 2,4,5-TP (Silvex) 105
Exhibit 88: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 2,4,5-TP (Silvex) 106
Exhibit 89: Analytical Methods for Arsenic 107
Exhibit 90: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Arsenic 108
Exhibit 91: Analytical Methods for Beryllium 109
Exhibit 92: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Beryllium 110
Exhibit 93: Analytical Methods for Cadmium Ill
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Exhibit 94: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Cadmium 112
Exhibit 95: Analytical Methods for Chromium 113
Exhibit 96: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Chromium 114
Exhibit 97: Analytical Methods for Copper 115
Exhibit 98: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Copper 116
Exhibit 99: Analytical Methods for Cyanide 117
Exhibit 100: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Cyanide 118
Exhibit 101: Analytical Methods for Dalapon 119
Exhibit 102: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Dalapon 120
Exhibit 103: Analytical Methods for 1,2-Dichlorobenzene 121
Exhibit 104: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,2-Dichlorobenzene 122
Exhibit 105: Analytical Methods for 2,4-D 123
Exhibit 106: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 2,4-D 124
Exhibit 107: Analytical Methods for Di(2-ethylhexyl)adipate 125
Exhibit 108: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - DEHA 126
Exhibit 109: Analytical Methods forDinoseb 127
Exhibit 110: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Dinoseb 128
Exhibit 111: Analytical Methods for Diquat 129
Exhibit 112: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Diquat 130
Exhibit 113: Analytical Methods forEndothall 131
Exhibit 114: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Endothall 132
Exhibit 115: Analytical Methods forEndrin 133
Exhibit 116: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Endrin 134
Exhibit 117: Analytical Methods for Fluoride 135
Exhibit 118: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Fluoride 136
Exhibit 119: Analytical Methods for Glyphosate 137
Exhibit 120: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Glyphosate 138
Exhibit 121: Analytical Methods for Lead 139
Exhibit 122: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Lead 140
Exhibit 123: Analytical Methods for Mercury 141
Exhibit 124: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Mercury 142
Exhibit 125: Analytical Methods for Nitrate 143
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Exhibit 126: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Nitrate 144
Exhibit 127: Analytical Methods for Oxamyl 145
Exhibit 128: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Oxamyl 146
Exhibit 129: Analytical Methods for Picloram 147
Exhibit 130: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Picloram 148
Exhibit 131: Analytical Methods for Selenium 149
Exhibit 132: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Selenium 150
Exhibit 133: Analytical Methods for Simazine 151
Exhibit 134: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Simazine 152
Exhibit 135: Analytical Methods for Xylenes 153
Exhibit 136: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Xylenes 154
Exhibit 137: Second Six-Year Review Analytical Feasibility Assessment Summary Analytes
with MCL Equal to the Current PQL, and thus the PQL is Limiting - 25 Analytes 157
Exhibit 138: Second Six-Year Review Analytical Feasibility Assessment Summary Analytes
with MCL Greater than the Current PQL and Thus it is Technically Feasible to Reduce the MCL
-41 Analytes 160
Appendix A
Exhibit A-l: New or Revised Analytical Methods since 2000; Review of NPDWRs under 40
CFR §§141.23, 141.24, and 141.131 A-l
Appendix B
Exhibit B-l: U.S. EPA National Primary Drinking Water Standards and Related Information -
Radionuclides B-l
Exhibit B-2: Availability of Six-Year 1 PE Data and Six-Year 2 PE/PT Data for Radionuclides
B-3
Exhibit B-3 Evaluation of ERA PT Data-Gross Alpha B-4
Exhibit B-4 Evaluation of ERA PT Data-Radium-226 B-5
Exhibit B-5 Evaluation of ERA PT Data-Radium-228 B-6
Exhibit B-6 Evaluation of ERA PT Data-Uranium B-7
Exhibit B-7 Evaluation of ERA PT Data-Gross Beta B-8
Exhibit B-8 Evaluation of ERA PT Data-Barium-133 B-9
Exhibit B-9: Evaluation of ERA PT Data-Cobalt-60 B-10
Exhibit B-10: Evaluation of ERA PT Data-Cesium-134 B-ll
Exhibit B-l 1: Evaluation of ERA PT Data-Cesium-137 B-12
Exhibit B-12: Evaluation of ERA PT Data-Iodine-131 B-13
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Exhibit B-13: Evaluation of ERA PT Data-Strontium-89 B-14
Exhibit B-14: Evaluation of ERA PT Data- Strontium-90 B-15
Exhibit B-15: Evaluation of ERA PT Data-Tritium B-16
Exhibit B-16: Evaluation of ERA PT Data-Zinc-65 B-17
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1.0 Introduction
The Safe Drinking Water Act (SDWA), as amended in 1996, requires the Environmental
Protection Agency (EPA) to review and revise, if appropriate, existing National Primary
Drinking Water Regulations (NPDWRs). As part of the review, EPA developed a protocol
document (USEPA, 2003a) that describes the process and strategy EPA uses to review existing
NPDWRs in order to meet its statutory requirement. The protocol was based on the
recommendations from the National Drinking Water Advisory Council (NDWAC), internal
Agency deliberations, and discussions with the diverse stakeholders involved in drinking water
and its protection. The protocol enables EPA to target those NPDWRs that are the most
appropriate candidates for revision and thus efficiently utilize its resources. As part of the
review, and where appropriate, EPA reviews the following key technical elements to make
decisions regarding regulatory changes: health effects assessments; technology assessments
(analytical feasibility and treatment technology); other regulatory revisions (e.g., monitoring and
reporting); occurrence and exposure analyses; and available economic information. This
document discusses the analytical feasibility aspect of the second Six-Year Review.
Analytical feasibility assessment is one of the key components of regulations review
because the analytical feasibility may have been the limiting factor in setting the Maximum
Contaminant Level (MCL) for some of the existing NPDWRs or because the health effects
reviews may indicate a potential change in the Maximum Contaminant Level Goal (MCLG).
This document examines analytical method performance over time by determining if the
Practical Quantitation Levels (PQLs) may have changed since promulgation. The PQL is
defined as "the lowest achievable level of analytical quantitation during routine laboratory
operating conditions within specified limits of precision and accuracy" (50 FR 46902, November
13, 1985) and is derived from the laboratory accreditation studies performed as part of the
drinking water laboratory certification program. Data from these studies was referred to as
Performance Evaluation (PE) data while the program was under EPA oversight until 1999, and
as Proficiency Testing (PT) data when the program was privatized with the National
Environmental Laboratory Accreditation Conference (NELAC) providing oversight.
Analytical method performance is also assessed by comparing the Method Detection
Limits (MDLs) of the analytical methods which were available at the time of promulgation to
those of the currently approved methods. The purpose is to determine if PQL changes based on
the PE/PT data are also supported by the approval and availability of new/improved methods to
the testing laboratories.
For the first Six-Year Review, EPA performed PQL assessments for 40 analytes that met
either of the following two criteria:
First, for those contaminants where the MCL is currently limited by analytical feasibility
(i.e., the MCL is set at the PQL) and the MCLG is still appropriate, EPA evaluated the
currently approved methods for those contaminants and available PE data to determine
whether it might be possible to lower the PQL and hence set an MCL that is closer to the
MCLG.
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The second circumstance under which EPA re-evaluated the PQL was for contaminants
identified under the Six-Year health effects technical review as having potential changes
to their MCLG. Because the information for the health effects review was not completely
available at the time the analytical methods analysis began, EPA took a broad-brush
approach and included a number of contaminants that may not have needed a
reassessment of their analytical feasibility.
In this document, PQL assessments are presented for all regulated contaminants for
which data was available, using both the original data from the first Six-Year Review (all
available data for regulated analytes; not just the 40 prioritized for Six-Year 1) and the new data
for the second Six-Year Review, and on approval and availability of new and improved methods.
The goal is to create a comprehensive document regarding laboratory analytical performance for
regulated analytes based on available approaches.
During the course of this study, EPA noted that for the Six Year Review 2 it did not have
sufficient data or the data was inconclusive to actually recalculate any PQLs for the reasons
discussed later in the report. PE/PT results were either not available below the current PQL, the
concentrations of interest, or the results were inconclusive/inadequate regarding a potential to
revise PQL. This limited EPA to use the data only to indicate a potential trend (qualitative
assessment) for PQL revision. In view of this, EPA explored the use of two other sources of
information regarding the potential to revise PQL: the minimum reporting levels (MRLs) in the
Six Year Review Information Collection Request (ICR) data set and the MDL multiplier
approach. These approaches and their results are discussed in a separate document prepared by
EPA entitled: Development of Estimated Quantitation Levels for the Six-Year Review of
National Primary Drinking Water Regulations (USEPA, 2009).
2.0 Background
2.1 Relationship Between SDWA Requirements and Analytical Methods
Section 1401(l)(C)(i) of SDWA (as amended in 1996); 42 U.S.C. § 300f(l)(C)(i), states
that an MCL for a national primary drinking water regulation is set "if, in the judgment of the
Administrator, it is economically and technologically feasible to ascertain the level of such
contaminant in water in public water systems." According to SDWA, NPDWRs include "criteria
and procedures to assure a supply of drinking water which dependably complies with such
maximum contaminant levels; including accepted methods of quality control and testing
procedures to insure compliance with such levels" [§1401(1)(D) of SDWA; 42 U.S.C. §
300f(l)(D)]. Except in certain circumstances, EPA is to set the MCL as close to the MCLG as is
feasible with the best available technologies (Section 1412 (b)(4)(B)) of SDWA. The MCLs for
several SDWA contaminants were set at levels higher than MCLGs due to the limits of the
analytical feasibility at that time. Since the promulgation of pre-1996 SDWA NPDWRs, newer
analytical methods and updated methods for measuring SDWA contaminants have been
approved. The approval of newer analytical techniques may have provided laboratories with the
analytical capability to measure some contaminants at lower levels. In addition, some
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laboratories may have improved in their ability to measure at lower levels using the same
methods that were originally promulgated.
In considering analytical methods for use in compliance monitoring, EPA evaluates the
overall sensitivity of the techniques. In previous regulations, EPA has used two measures of
analytical capability, the MDL and the PQL.
The MDL is a measure of method sensitivity. The MDL is defined at 40 CFR Part 136
Appendix B as "the minimum concentration of a substance that can be reported with 99%
confidence that the analyte concentration is greater than zero." MDLs can be operator,
method, laboratory, and matrix-specific. Due to normal day-to-day and run-to-run
analytical variability, MDLs may not be reproducible within a laboratory or between
laboratories. The regulatory significance of the MDL is that EPA uses the MDL to
determine when a contaminant is considered to be detected and it can be used to calculate
a PQL for that contaminant.
The PQL is defined as "the lowest achievable level of analytical quantitation during
routine laboratory operating conditions within specified limits of precision and accuracy"
(56 FR 46902, November 13, 1985). The Agency has used the PQL to estimate or
evaluate the minimum concentration at which most laboratories can be expected to
reliably measure a specific chemical contaminant during day-to-day analyses of drinking
water samples. The PQL is a means of integrating information on the performance of the
approved analytical methods into the development of a drinking water regulation (52 FR
25690, July 8, 1987). The PQL incorporates the following (50 FR 46880, November 13,
1985; 52 FR 25690, July 8, 1987; 54 FR 22062, May 22, 1989):
- quantitation,
- precision and bias,
normal operations of a laboratory, and
the fundamental need to have a sufficient number of laboratories available to conduct
compliance monitoring analyses.
In some cases, the quantitation level for a particular analyte may have been the limiting
factor in the determination of the MCL for that analyte. This could be especially true for
contaminants with MCLGs of zero. In addition, there are several SDWA contaminants with non-
zero MCLGs that have their MCL set at the PQL.
2.2 PQL Determination Methods for the SDWA Contaminants
Historically, EPA has used two main approaches to determine a PQL for SDWA
analytes. One approach (and the preferred approach) used data from laboratory Performance
Evaluation (PE studies, now called PT or Proficiency Testing studies). Although the primary use
of the PE/PT data was for EPA's laboratory certification, the data were also used as a secondary
data source for many years to develop PQLs when the spike concentrations were in the
appropriate concentration range. The derivation of the PQL involved determining the
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concentration of an analyte at which 75% of all participating laboratories achieved results within
a specified range around the spike value.
A PQL derived in such a manner is considered a stringent target for routine laboratory
performance because:
PE/PT samples are prepared in reagent water and therefore do not contain the matrix
interferences that may occur in field samples.
Laboratories analyze only a small number of samples for the study and are aware that the
samples are for the purposes of performance evaluation (i.e., they are not "blind"
samples).
In deriving a PQL from the laboratory performance data, the Agency typically sets a
fixed percentage or 2 sigma (2 standard deviation) acceptance window around the known
concentration (or spike value) of the samples. While the acceptance limits for inorganics
typically range from 15 to 30% (40 CFR §141.23(k)(3)(ii)), the acceptance limits for organics
generally range from 20 to 50% (40 CFR §141.24(f)(17)(i) and 40 CFR §141.24(h)(19)(i)).
Several SDWA analytes have acceptance limits of 2 sigma (2 standard deviations). The
percentage of laboratories achieving results within the specified acceptance window (y-axis) is
plotted against the known spike concentration of the PE/PT samples (x-axis). Linear regression
or graphical analysis is performed to determine the concentration at which 75% of the
participating laboratories achieve acceptable results.
In the absence of PE/PT data, EPA has relied on the MDL multiplier method. In this
approach, a PQL is calculated by multiplying the EPA-derived MDL by a factor of 5 or 10. The
5 or 10 multiplier is used to account for the variability and uncertainty that can occur at the
MDL. The MDL multiplier method was mostly used in the early years of rule development for
NPDWRs when insufficient PE/PT data were available. Once sufficient data became available,
most of the PQLs that were developed using the MDL multiplier were validated using PE/PT
data.
There are advantages and disadvantages for each of these approaches. Some of the
advantages and disadvantages for these PQL derivation approaches are as follows:
(1) PE/PT data to derive a new PQL
Advantages -
Uses inter-laboratory data collected at concentrations near the MCL.
More representative of what methods are being used for the analysis of that contaminant.
May be the preferred approach for contaminants with MCLGs of zero because MCLs for
these contaminants are set at the PQL and EPA strives to use their preferred approach in
these cases.
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Disadvantages -
The PQL derived for each contaminant is affected by EPA's choice of "an acceptable
level of precision." Acceptance criteria are not the same for all methods or contaminants.
These levels have been set at + 10% or more (see Exhibit 2).
PT data from 1999 and earlier are obtained from varying numbers of laboratories; hence
some passing rates may represent dozens of laboratories, while others may represent very
few laboratories. Despite this, linear regression treats each national passing rate equally.
Further, passing rates of near 100% can influence the regression line in such a manner as
to "mask" low passing rates below 75%. For example, if at higher concentrations the
passing rates are all at or near 100%, but at lower concentrations near the PQL there are
several passing rates well below 75%, the resultant regression line may still predict
greater than 75% of laboratories to pass over the entire range of true (or spike)
concentrations even though the data near the PQL demonstrate that this may not be the
case.
During Six Year 1, some stakeholders felt that the PQL may be influenced by the set of
data used (i.e., using data from all laboratories as opposed to only using data from EPA
State and Regional laboratories, which was the case with Six Year 1 data).
Some stakeholders felt that the laboratory performance may be skewed because PE/PT
samples may be treated as special samples that are critical for laboratory certification.
The derivation of PQLs from laboratory performance data is a resource- and time-
intensive process.
PE/PT data are generated as part of the drinking water laboratory certification program
which is designed to test precision and accuracy around the MCL. Therefore,
concentrations representing laboratory performance at orders of magnitude below the
current MCL are generally not represented.
(2) The MDL-Multiplier Approach
Advantage
It is a relatively easy and straightforward process
Disadvantages
A PQL derived from the MDL using a multiplier to account for laboratory variability and
uncertainty may not be practical or realistic.
Several methods with varying MDLs may be approved for the same contaminant and it
can be difficult to decide which Method/MDL to select for the PQL calculation.
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2.3 Operational Details of the PE/PT Programs
PE studies were an integral part of EPA's certification program for drinking water
laboratories for over 20 years (thru 1999). Historically, performance studies were conducted
semi-annually by EPA for all current and proposed drinking water contaminants. Although the
studies were conducted semi-annually, for certification purposes, laboratories were only required
to demonstrate acceptable performance once a year (40 CFR 141.23(k)(3) and 141.24(f)(17)).
PE study samples (spike samples) were sent to all laboratories that conduct drinking water
analyses, including utility laboratories, commercial laboratories, and State and EPA Regional
laboratories. Samples or sample concentrates that were analyzed, contained all SDWA analytes
and analytes that were being considered for regulation under the SDWA.
As part of these studies, EPA's National Exposure Research Laboratory (NERL) in
Cincinnati, Ohio, sent participating laboratories a set of stable sample concentrates in sealed
glass ampules, a data reporting form, and appropriate instructions. Each laboratory produced the
study samples by diluting a measured quantity of the specific concentrates to volume with
reagent water. The laboratory then analyzed the samples using an EPA-approved method of
their choice. The completed reporting form was sent to EPA for evaluation, the data were
carefully reviewed per Quality Assurance/Quality Control (QA/QC) procedures, entered into a
database, and a fully detailed report was then returned to each laboratory. The responsible State
or EPA office contacted those laboratories that demonstrated potential problems.
Performance Evaluation studies are no longer performed by EPA. In December 1999, the
PT program was privatized, with NELAC providing oversight to what is now referred to as the
PT program. NELAC is a cooperative association of State and Federal agencies and, in 2006,
NELAC and the Institute for National Environmental Laboratory Accreditation combined to
form The NELAC Institute (TNI). For the purposes of this document, "NELAC" is used to
represent both NELAC and TNI. PT data services under the NELAC's program are provided by
private companies that prepare and provide PT samples (spiked at concentrations in accordance
with NELAC policies) to analytical laboratories as part of maintaining laboratory accreditation.
Approximately 10-12 such PT providers (e.g., Environmental Resource Associates - ERA) exist
nationwide. PT providers also compile the results of the PT analyses for use by NELAC.
Privatization of the PT program made it harder for the Agency to obtain PT data. As a
result, during the second six year review, only one PT provider (ERA) was willing to share
national pass/fail rates with EPA (see Section 2.4 for further discussion). ERA provided EPA
with general summary statistics and national failure rates; however, no information regarding
laboratory identification was shared, thereby maintaining laboratory confidentiality. Depending
on the analyte and/or concentration, the PT data from ERA may represent more than 70
laboratories at any single concentration. According to ERA personnel, since December 1999,
when the PT process was privatized, ERA has accounted for approximately 50% of all PT results
nationwide.
A laboratory either passes or fails for each analyte based upon the Acceptance Limits
(NELAC now refers to these as Acceptance Criteria) for each analyte. Acceptance Criteria can
be percentage based (e.g., ą 30% of the spiked, or true value), standard deviation-based (e.g., ą 2
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standard deviations, as described in Section 5.2), or based on average and range of replicate
analyses (radionuclides only). In certain cases (e.g., volatile organic compounds - VOCs) the
acceptance criteria may differ depending on the concentration (e.g., ą 40% for spike
concentrations <10 (ig/L and + 20% for concentrations > 10 ng/L).
The key differences between EPA's PE program and the current NELAC PT program in
terms of the utility of the data for PQL assessment are described in Exhibit 1. For PQL
assessment, the most significant implication of the differences between the two programs is that,
while more laboratories and more spiking concentrations are represented in the NELAC PT data,
fewer analytes have data at or below their PQL. As the PE/PT programs were designed for the
purpose of laboratory accreditation, both programs exhibited shortcomings with respect to the
use of the data for PQL assessment. As far as the data from the NELAC PT program is
concerned, EPA would have benefitted if a) data from all PT providers were available, and b)
additional spike concentrations for PT samples were selected below the current PQLs.
Exhibit 1: Summary of Differences Between EPA's PE Program and NELAC's PT
Program1
Laboratory Accreditation
Program Feature
Number of Laboratories
Participating
Types of Laboratories
Participating
Number of True (Spike)
Concentrations Evaluated/
analyte
Number of True (Spike)
Concentrations Below the PQL
Amount of Data Available to EPA
for PQL Assessment (% of the
National PT data)
Data Broken Down by Analytical
Method?
During EPA PE Period
Wide range but typically 1 0 - 60
laboratories per concentration
EPA Regional and State
laboratories - Narrow spectrum of
laboratories and relatively
uniform in performance
Approximately 1 0 - 30
Of the 66 analytes which had PE
data for PQL assessment, 39
analytes had data < the current
PQL^
Percentage unknown
Yes
During NELAC PT Period
Wide range but typically 1 0 - 70
laboratories per concentration
Public Water System, academic
and private with some EPA
regional and State laboratories -
Broad spectrum of laboratories
with wide performance range
59-60
Of the 66 analytes which had PT
data for PQL assessment, 22
analytes had data < the current
PQL
Approximately 50% of the
national PT data
No
Excludes radionuclides
Passing rates at or below the PQL could not be calculated for dalapon, DEHA, endothall or simazine
because the NELAC regression coefficients that are used to calculate national passing rates (see
Section 5.2) are not valid at or below the PQL for these four analytes. As a result only 35 of the 39 analytes
have passing rates at or below the PQL
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2.4 Efforts Made to Obtain PT Data
The following is a summary of efforts that were made by EPA to obtain nationally-
representative PT data from the private firms that now provide PT services and/or directly from
NELAC:
EPA first searched the websites of various PT providers to find out if the laboratory
performance data was posted on-line. Although, some PT providers (e.g., APG of Belpre, OH)
posted various PT statistics online, it did not include the passing/failing rates at each spike
concentration which was needed for PQL assessment. At that point, requests for data were sent
or discussed with PT Providers, members of the NELAC PT Committee and members of the
NELAC PT Board. Only basic information was requested: the contaminant name being tested;
the concentration of the PT sample; the number of labs in the PT round (no names or IDs, just
the total number); and the number of labs that passed and/or number of labs that failed at each
concentration. In all contacts, it was made clear that EPA needed just this basic information and
would not require the identity of any individual lab, etc., and would not require the disclosure of
what could be considered confidential business information (CBI).
After multiple attempts, it was made clear by NELAC and the PT providers contacted
that the data were considered to be CBI and therefore, could not be released. One exception to
this was the PT provider ERA of Arvada, Colorado. ERA willingly and quickly sent their failure
rates, true concentrations and basic summary statistics to EPA in August 2004. Note that ERA
provided summary statistics and national failure rates as cited above, and no information
regarding laboratory identification or other CBI was provided by ERA. Although APG also
provided to EPA many hundreds of pages of analyzed data from the PT program across the
country, it did not include the passing/failing rates at each concentration that were needed for
PQL assessment.
3.0 Representativeness of Available PT Data
During the period when the available Six-Year 2/ERA data were generated, there were
approximately 10-12 companies that provided PT data services nationwide (a review of the TNI
website indicates that that number is smaller in 2009). Only one of these providers, ERA, was
willing to provide their pass/fail rates to EPA. According to ERA personnel, since December
1999, when the PT process was privatized, they account for approximately 50% of all PT results
nationwide. As described in Section 2.4, substantial efforts were made to obtain additional PT
data to no avail. The assessments made in this report are based on PT data that were available,
and this limitation is recognized. The refusal of other PT providers/NELAC to provide results
raises some questions about the validity of the data set available to EPA. In other words, is the
available data set sufficient to perform the assessments herein? The issues can be divided into
three broad areas: bias, precision, and the regression model.
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3.1 Bias
The refusal of providers other than ERA to provide data introduces potential non-
response bias. If ERA procedures and results are different from that of other providers, the data
may not be representative. Because no data are available from the other providers, it is difficult
to quantify the potential bias. EPA considered options to evaluate the potential bias:
Compare ERA's data to existing EPA data from the first Six-Year Review. EPA can test
whether the percentage of laboratories passing is significantly different for individual
analytes. However, because laboratory performance tends to improve over time, the
degree of difference between ERA and other providers from Six-Year 1 becomes
confounded.
Collect and compare any available information about the procedures used by ERA and
the other providers. This includes the processes used to identify and collect data from
laboratories, quality control measures, and analytical approaches. Given the lack of
response from other PT providers, this is not likely to be feasible.
EPA could use this information to evaluate the results from ERA. EPA could make
subjective judgments about the potential sign and magnitude of the bias, and might also conduct
sensitivity analyses to explore the potential impact of the non-response bias on the results.
3.2 Precision
For EPA to determine whether the available data are adequate for its analysis, EPA
needed to establish data quality objectives for its analysis. An important data quality objective
that is affected by the size of the sample is the precision of the estimates made with the sample.
EPA could consider:
The margin of error the Agency is willing to tolerate The data are used to estimate
regression parameters and a predicted regression line. A prediction interval can be
estimated for the regression line. EPA could specify the size of this prediction interval,
and might also want to consider the size of the confidence interval for each parameter of
the regression model.
The confidence level the Agency requires for its estimates. Confidence levels are
usually expressed as 1-a, where a is the probability of a type I error. In other words, the
probability that the prediction interval includes the true regression line is 1-a percent. It
is common to estimate either a 95 percent or 99 percent prediction interval.
Sampling is not the only source of uncertainty in the analysis, as is discussed in the next
section. But EPA also considered the impact of the sample size on the regression error. This
requires a subjective judgment regarding the level of error EPA is willing to tolerate; the Agency
could then consider the impact the margin of error may have on the PQL determination through a
sensitivity analysis.
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3.3 The Regression Model
The PT data are used to estimate a simple linear regression using ordinary least squares
(OLS). The regression of the percentage of laboratories passing at the spiked concentrations of
an analyte is used in recalculation of the PQL. The standard results of the theory of linear
regression is not entirely suited for sample surveys. The theory assumes the population is
infinite, or that the observed finite population is drawn from an infinite superpopulation. This
implies that sampling error is not the only source of error in a regression estimate. In fact, the
error of the regression estimate consists of three parts, as discussed below.
The use of a sample is one potential source of error. It is useful to think of the regression
as an estimate of the conditional mean of the percentage of laboratories passing. The average
estimate of the mean across repeated samples will equal the true population mean. But the mean
of a specific sample may differ from the population mean. The second source of error is in the
estimated parameters of the regression model. The regression is of the form (Weisberg, 1985):
(1) Yi=#>+M + S
Where:
Y; = Dependent variable for observation i. (e.g., laboratory passing rate for true concentration
i);
Po = Intercept or constant which tells us the expected value of Y when X is equal to zero, (e.g.,
the observed concentration in a sample that has not been spiked);
PI = The slope, or the change in Y for a change in x;
x; = The independent variable for observation i (the true concentration for observation i);
Si = Random error, or the difference between the observed passing rate and the model's
prediction. It is due to random error or variables excluded from the model. (Which,
ideally, are not correlated with the independent variables.)
It is estimated by:
(2) Y = b0 + 6ix
Where:
Y = The fitted value predicted by the model.
The parameters bo and b\ are unbiased estimates of/?o and/?i (the true parameters), but
they can differ for a particular finite population.
Finally, the error of an individual prediction has a third component, the difference
between the observed percentage for a true concentration and the average percentage for that
concentration. This is Ģ; in equation (1). The parts of the error are independent, so the variance
of the prediction error is the sum of the three variances. Even if the regression estimate is based
on the entire (finite) population, these last two components of error remain.
10
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4.0 Identification of Regulated Analytes for PQL Assessment
For the first Six-Year analytical feasibility review, EPA focused on assessing whether the
PQL had changed since promulgation for a subset of the 68 chemical NPDWRs. EPA identified
and performed the analytical feasibility analysis for a total of 40 NPDWRs based on the
priorities discussed in Section 1.0.
For the second Six-Year analytical feasibility review, EPA's goal is to create a
comprehensive document that includes PQL assessments for all regulated analytes for which PT
data are available. Exhibit 2 summarizes these analytes, along with their range of MDLs, current
PQL, how the PQL was determined, their MCLG, MCL, and the current acceptance criteria for
PT.
Exhibit 2: U.S. EPA National Primary Drinking Water Standards and Related
Information1
Analyte
CASRN
Acrylamide
79-06-1
Alachlor
15972-60-8
Antimony
7440-36-0
Arsenic
7440-38-2
Atrazine
1912-24-9
Barium
7440-39-3
Benzene
71-43-2
Benzo[a]pyrene
50-32-8
Beryllium
7440-41-7
Bromate
15541-45-4
Cadmium
7440-43-9
Carbofuran
1563-66-2
Carbon tetrachloride
56-23-5
Chlordane
57-74-9
EPAMDLor
Range
(mg/L)2
N/A
0.000005 -
0.000225
0.00002 -
0.0008
0.0001 -
0.008
0.000003 -
0.0024
0.00004-
0.001
0.00001 -
0.00004
0.000016-
0.00023
0.00002-
0.0003
0.00012-
0.00144
0.00003 -
0.001
0.000043 -
0.00052
(note: lower
bound = DL)
0.000002 -
0.00021
0.000001 -
0.000224
PQL
(mg/L)
N/A
0.002
0.006
0.003
0.001
0.15
0.005
0.0002
0.001
0.01
0.002
0.007
0.005
0.002
How PQL
Determined?
N/A
IMDLxlO
PE Data
PE Data
PE Data
PE Data
RDLxlO
PE Data
PE Data
N/A
PE Data
IMDLxlO
PE Data
IMDLxlO
MCLG
(mg/L)
Zero
Zero
0.006
Zero
0.003
2
Zero
Zero
0.004
Zero
0.005
0.04
Zero
0.002
MCLorTT
(mg/L)
TT3
0.002
0.006
0.010
0.003
2
0.005
0.0002
0.004
0.01
0.005
0.04
0.005
0.002
Acceptance
Criteria
N/A
+ 45%
+ 30%
+ 30%
+ 45%
+ 15%
ą 20% or 40%
Mean +
2 Std Dev
+ 15%
Mean +
2 Std Dev
(changed to
+ 30%, 2007)
ą 20%
+ 45%
+ 20% or 40%
+ 45%
Page 11
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Analyte
CASRN
Chlorite
7758-19-2
Chromium (total)
Crlll: 16065-83-1
CrVI: 18540-29-9
Copper
7440-50-8
Cyanide
(as free cyanide)
57-12-5
Dalapon
75-99-0
1,2-Dibromo-3-
chloropropane (DBCP)
96-12-8
1 ,2-Dichlorobenzene
(o-Dichlorobenzene)
95-50-1
1 ,4-Dichlorobenzene
(p-Dichlorobenzene)
106-46-7
1,2-Dichloroethane
(Ethylene dichloride)
107-06-2
1,1-Dichloroethylene
75-35-4
c/s-1,2-
Dichloroethylene
156-59-2
frans-1,2-
Dichloroethylene
156-60-5
Dichloromethane
(Methylene chloride)
75-09-2
2,4-
Dichlorophenoxy acetic
acid (2,4-D)
94-75-7
1,2-Dichloropropane
78-87-5
Di(2-ethylhexyl)adipate
(DEHA)
103-23-1
Di(2-ethylhexyl)
phthalate (DEHP)
117-81-7
Dinoseb
88-85-7
Diquat
85-00-7
Endothall
145-73-3
EPAMDLor
Range
(mg/L)2
0.00045-
0.01
0.00008-
0.004
0.00001 -
0.003
N/A
0.000024 -
0.0013
0.000006 -
0.00001
0.00002-
0.00005
0.00001 -
0.00004
0.00002-
0.00006
0.00004 -
0.00012
0.00001 -
0.00012
0.00003-
0.00006
0.00001 -
0.00009
0.000055 -
0.0013
0.00001 -
0.00004
0.00009-
0.01182
0.00046-
0.00225
0.000081 -
0.0015
0.00072
0.0007 -
0.00179
PQL
(mg/L)
N/A
0.01
0.05
0.1
0.01
0.0002
0.005
0.005
0.005
0.005
0.005
0.005
0.005
0.005
0.005
0.006
0.006
0.002
0.004
0.09
How PQL
Determined?
N/A
PE Data
PE Data
PE Data
MDLxlO
IMDLxlO
MDL survey
and PE Data
PE Data
PE Data
PE Data
MDL survey
and PE Data
MDL survey
and PE Data
PE Data
Raised to
near MCL
MDL survey
and PE Data
MDLxlO
PE Data
MDLxlO
PE Data
MDLx 10
MCLG
(mg/L)
0.8
0.1
1.3
0.2
0.2
Zero
0.6
0.075
Zero
0.007
0.07
0.1
Zero
0.07
Zero
0.4
Zero
0.007
0.02
0.1
MCLorTT
(mg/L)
1.0
0.1
TT5 Action level
1.3
0.2
0.2
0.0002
0.6
0.075
0.005
0.007
0.07
0.1
0.005
0.07
0.005
0.4
0.006
0.007
0.02
0.1
Acceptance
Criteria
+30%
+ 15%
+ 10%
+ 25%
Mean +
2 Std Dev
+ 40%
+ 20% or 40%
+ 20% or 40%
+ 20% or 40%
+ 20% or 40%
+ 20% or 40%
+ 20% or 40%
+ 20% or 40%
+ 50%
+ 20% or 40%
Mean +
2 Std Dev
Mean +
2 Std Dev
Mean +
2 Std Dev
Mean +
2 Std Dev
Mean +
2 Std Dev
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Analyte
CASRN
Endrin
72-20-8
Epichlorohydrin
106-89-8
Ethylbenzene
100-41-4
Ethylene dibromide
(EDB)
106-93-4
Fluoride
16984-48-8
Glyphosate
1071-83-6
Heptachlor
76-44-8
Heptachlor epoxide
1024-57-3
Hexachlorobenzene
118-74-1
Hexachlorocyclopenta-
diene
77-47-4
Lead
7439-92-1
Lindane
58-89-9
Mercury (Inorganic)
7439-97-6
Methoxychlor
72-43-5
Monochlorobenzene
(Chlorobenzene)
108-90-7
Nitrate (as N)
14797-55-8
Nitrite (as N)
14797-65-0
Oxamyl (Vydate)
23135-22-0
Pentachlorophenol
87-86-5
Picloram
1918-02-1
Polychlorinated
biphenyls (PCBs) as
Decachlorobiphenyl
(DCBP)
1336-36-3
EPAMDLor
Range
(mg/L)2
0.000002 -
0.00034
N/A
0.00001 -
0.00006
0.000007 -
0.000032
0.009-0.01
0.00599-
0.006
0.0000015-
0.00015
0.000001 -
0.000202
0.000001 -
0.00013
0.000004 -
0.00016
0.00002-
0.0007
0.000002 -
0.00015
0.0000018-
0.0002
0.000003 -
0.00096
0.00001 -
0.00004
0.002 - 0.008
0.001 -0.004
0.000044 -
0.00086
0.000014-
0.0016
Not
Recovered -
0.001
As
Decachlorobi-
phenyl
(DCBP):
0.00008
As Aroclors:
0.000012-
0.0156
PQL
(mg/L)
0.0001
N/A
0.005
0.00005
0.5
0.06
0.0004
0.0002
0.001
0.001
0.005
0.0002
0.0005
0.01
0.005
0.4
0.4
0.02
0.001
0.001
0.0005
How PQL
Determined?
MDLxlO
N/A
MDL survey
and PE Data
IMDLxS
PE Data
PE Data
IMDLxlO
IMDLxlO
PE Data
PE Data
PE Data
MDLxlO
PE Data
Raised to
near MCL
MDLxlO
PE Data
PQL for
nitrate
MDLxlO
PE Data
DLxlO
PE Data
MCLG
(mg/L)
0.002
Zero
0.7
Zero
4
0.7
Zero
Zero
Zero
0.05
Zero
0.0002
0.002
0.04
0.1
10
1
0.2
Zero
0.5
Zero
MCLorTT
(mg/L)
0.002
TT3
0.7
0.00005
4
0.7
0.0004
0.0002
0.001
0.05
TT5, Action level =
0.015
0.0002
0.002
0.04
0.1
10
1
0.2
0.001
0.5
0.0005
Acceptance
Criteria
+ 30%
N/A
+ 20% or 40%
+ 40%
+ 10%
Mean +
2 Std Dev
+ 45%
+ 45%
Mean +
2 Std Dev
Mean +
2 Std Dev
+ 30%
+ 45%
+ 30%
+ 45%
+ 20% or 40%
+ 10%
+ 15%
Mean +
2 Std Dev
+ 50%
Mean +
2 Std Dev
+ 100%
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Analyte
CASRN
Selenium
7782-49-2
Simazine
122-34-9
Styrene
100-42-5
2,3,7,8-TCDD (Dioxin)
1746-01-6
Tetrachloroethylene
127-18-4
Thallium
7440-28-0
Toluene
108-88-3
Toxaphene
8001-35-2
2,4,5-TP (Silvex)
93-72-1
1 ,2,4-Trichlorobenzene
120-82-1
1,1,1-Trichloroethane
71-55-6
1 , 1 ,2-Trichloroethane
79-00-5
Trichloroethylene
79-01-6
Vinyl chloride
75-01-4
Xylenes (total)
1330-20-7
EPAMDLor
Range
(mg/L)2
0.0005 -
0.0079
0.000008 -
0.0068
0.00001 -
0.0001
1.E-8
(note: value
is an ML)
0.000002 -
0.00014
0.00001 -
0.0007
0.00001 -
0.00011
0.00013-
0.0017
0.000018-
0.0018
0.00002 -
0.0002
0.000005 -
0.00008
0.000012-
0.0001
0.000002 -
0.00019
0.00001 -
0.00018
0.00001 -
0.00013
PQL
(mg/L)
0.01
0.0007
0.005
3x10'8
0.005
0.002
0.005
0.003
0.005
0.005
0.005
0.005
0.005
0.002
0.005
How PQL
Determined?
PE Data
MDLxlO
MDL survey
and PE Data
MDLxS
MDL survey
and PE Data
PE Data
MDL survey
and PE Data
PE Data
Raised to
near MCL
MDLxlO
DLxlO
PE Data
PE Data
MLPD
MDL survey
and PE Data
MCLG
(mg/L)
0.05
0.004
0.1
Zero
Zero
0.0005
1
Zero
0.05
0.07
0.2
0.003
Zero
Zero
10
MCLorTT
(mg/L)
0.05
0.004
0.1
3x10'8
0.005
0.002
1
0.003
0.05
0.07
0.2
0.005
0.005
0.002
10
Acceptance
Criteria
+ 20%
Mean +
2 Std Dev
+ 20% or 40%
Mean +
2 Std Dev
+ 20% or 40%
+ 30%
+ 20% or 40%
+ 45%
+ 50%
+ 20% or 40%
+ 20% or 40%
+ 20% or 40%
+ 20% or 40%
+ 40%
+ 20% or 40%
Definitions
Chemical Abstracts Services Registry Number (CASRN)
Maximum Contaminant Level (MCL) - The highest level of a contaminant that is allowed in drinking water. MCLs
are set as close to MCLGs as feasible using the best available treatment technology and taking cost into
consideration. MCLs are enforceable standards.
Treatment technique (TT) - A required process intended to reduce the level of a contaminant in drinking water.
DL = Detection Limit
IMDL = Interlaboratory Method Detection Limit
MDL = Method Detection Limit
ML = Minimum Level
MLPD = Multi-laboratory Performance Data
PQL = Practical Quantitation Level
RDL = Regulatory Detection Limit
The MDLs and/or ranges were obtained from the individual analytical methods developed by EPA; non-EPA
methods are not represented. Therefore, the MDL ranges presented may not represent the entire range of
possible values. Methods can be found at the National Environmental Methods Index website (NEMI, 2008).
Each water system must certify, in writing to the state (using third-party or manufacturers certification) that when it
uses acrylamide and/or epichlorohydrin to treat water, the combination (or product) of dose and monomer level
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does not exceed the levels specified, as follows: Acrylamide = 0.05% dosed at 1 mg/L (or equivalent);
Epichlorohydrin = 0.01% dosed at 20 mg/L (or equivalent).
4 MDL range for chlordane including a- and y-chlordane and trans-nonachlor.
5 Lead and copper are regulated by a Treatment Technique that requires systems to control the corrosiveness of
their water. If more than 10% of tap water samples exceed the action level, water systems must take additional
steps. For copper, the action level is 1.3 mg/L, and for lead is 0.015 mg/L. From 40 CFR Part 140 revised as of
July 1, 2003, and EPA 816-F-03-016 June 2003 (USEPA, 2003b).
6 MDL range for PCBs is from EPA Method 508A only. Other methods (505, 508.1 and 525.2) are screening
methods and are not used for comparison to MCLs.
PQL values and the basis for their determination can be found at 50 FR 46880, November 13, 1985; 52 FR 25690.
July 8, 1987; 53 FR 31516, August 18, 1988; 54 FR 22062, May 22, 1989; 55 FR 30370, July 25, 1990; 56 FR
3526, January 30, 1991; 57 FR 31776, July 17, 1992; 63 FR 69390, December 16, 1998; and EPA-815-R-00-010:
"Analytical Methods Support Document For Arsenic In Drinking Water" (USEPA, 1999).
Acceptance criteria are available at: http://www.nelac-institute.org/and at 40 CFR 141.24(f)(17)(i), 40 CFR
141.24(h)(19)(i)(B), 40 CFR 141.23(k)(3)(ii), 40 CFR 141.89(a)(1)(ii)(A), 40 CFR 141.89(a)(1)(ii)(B) and 40 CFR
5.0 Second Six-Year Review PQL Assessment Methodology
5.1 Data Available for PQL Assessment
Qualitative PQL assessments are based on all available laboratory performance data from
Six-Year 1 and from one major PT provider (ERA) that was willing to share PT data with EPA.
Exhibit 3 summarizes the availability of Six-Year 1 PE data and Six-Year 2 PT data and whether
data are available at or below the PQL for each analyte. Having data below the PQL is
considered to be important in concluding whether a PQL could be reduced, regardless of how
high passing rates are above the PQL. For non-radionuclides, the ERA dataset encompasses the
period from late 1999 through 2004. ERA data for radionuclides were generated from 2002-
2006.
A review of new or revised analytical methods that have been approved by EPA for the
analysis of regulated analytes was undertaken for the period of 2000 through 2007. The approval
and availability of these analytical methods might indicate an improvement in laboratory
analytical performance. New and updated methods for the regulated analytes are discussed in
each contaminant profile in Section 6. A complete listing of new and updated analytical methods
is provided in Appendix A.
Regression plots for radionuclides based on laboratory performance data obtained from
ERA (for the period 2002-2006) are presented in Appendix B. Radionuclides were not included
in the Six-Year 1 review and therefore, no data are available. Note that for the radionuclides,
limitations of laboratory performance at low concentrations is generally not an issue, as PQLs
can be lowered, if necessary, by increasing sample volume and/or radiological analysis duration.
Thus, though the radionuclide PT data are evaluated in this report for completeness, no
conclusions are drawn regarding changes in PQLs.
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Exhibit 3: Availability of Six-Year 1 PE Data and Six-Year 2 PT Data for Regulated
Analytes
Analyte
CASRN
Acrylamide
79-06-1
Alachlor
15972-60-8
Antimony
7440-36-0
Arsenic
7440-38-2
Atrazine
1912-24-9
Barium
7440-39-3
Benzene
71-43-2
Benzo[a]pyrene
50-32-8
Beryllium
7440-41-7
Bromate
15541-45-4
Cadmium
7440-43-9
Carbofuran
1563-66-2
Carbon tetrachloride
56-23-5
Chlordane
57-74-9
Chlorite
7758-19-2
Chromium (total)
CM II: 16065-83-1
CrVI: 18540-29-9
Copper
7440-50-8
Cyanide
(as free cyanide)
57-12-5
Dalapon
75-99-0
1 ,2-Dibromo-3-chloropropane (DBCP)
96-12-8
1 ,2-Dichlorobenzene
(o-Dichlorobenzene)
95-50-1
In Six-Year 1 Data?
No
Yes, some data < PQL
Yes, some data < PQL1
Yes, some data < PQL1
Yes, some data < PQL1
Yes, some data < PQL1
Yes, some data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, but no PQL
Yes, no data < PQL
Yes, some data < PQL1
Yes, only one datum =
PQL; no data < PQL
Yes, some data < PQL;
passing rates below
PQL could not be
calculated 2
Yes, some data < PQL
Yes, no data < PQL
In Six-Year 2 ERA Data
1999-2004?
No
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, but no PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
16
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EPA815-B-09-003
October 2009
Analyte
CASRN
1 ,4-Dichlorobenzene
(p-Dichlorobenzene)
106-46-7
1,2-Dichloroethane (Ethylene
dichloride)
107-06-2
1,1-Dichloroethylene
75-35-4
c/s-1 ,2-Dichloroethylene
156-59-2
frans-1 ,2-Dichloroethylene
156-60-5
Dichloromethane (Methylene chloride)
75-09-2
2,4-Dichlorophenoxyacetic acid (2,4-D)
94-75-7
1,2-Dichloropropane
78-87-5
Di(2-ethylhexyl)adipate (DEHA)
103-23-1
Di(2-ethylhexyl) phthalate (DEHP)
117-81-7
Dinoseb
88-85-7
Diquat
85-00-7
Endothall
145-73-3
Endrin
72-20-8
Epichlorohydrin
106-89-8
Ethylbenzene
100-41-4
Ethylene dibromide (EDB)
106-93-4
Fluoride
16984-48-8
Glyphosate
1071-83-6
Heptachlor
76-44-8
Heptachlor epoxide
1024-57-3
Hexachlorobenzene
118-74-1
Hexachlorocyclopentadiene
77-47-4
In Six-Year 1 Data?
Yes, some data < PQL
Yes, some data_< PQL1
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, some data < PQL;
passing rates below
PQL could not be
calculated 2
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL;
passing rates below
PQL could not be
calculated 2
Yes, no data < PQL1
No
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, some data_< PQL
In Six-Year 2 ERA Data
1999-2004?
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
No
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Analyte
CASRN
Lead
7439-92-1
Lindane
58-89-9
Mercury (Inorganic)
7439-97-6
Methoxychlor
72-43-5
Monochlorobenzene (Chlorobenzene)
108-90-7
Nitrate (as N)
14797-55-8
Nitrite (as N)
14797-65-0
Oxamyl (Vydate)
23135-22-0
Pentachlorophenol
87-86-5
Picloram
1918-02-1
Polychlorinated biphenyls (PCBs) as
Decachlorobiphenyl (DCBP)
1336-36-3
Selenium
7782-49-2
Simazine
122-34-9
Styrene
100-42-5
2,3,7,8-TCDD (Dioxin)
1746-01-6
Tetrachloroethylene
127-18-4
Thallium
7440-28-0
Toluene
108-88-3
Toxaphene
8001-35-2
2,4,5-TP (Silvex)
93-72-1
1 ,2,4-Trichlorobenzene
120-82-1
1,1,1-Trichloroethane
71-55-6
1 , 1 ,2-Trichloroethane
79-00-5
Trichloroethylene
79-01-6
In Six-Year 1 Data?
Yes, some data < PQL1
Yes, some data < PQL1
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, some data < PQL1
Yes, some data < PQL;
passing rates below
PQL could not be
calculated 2
Yes, no data < PQL
No
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, some data < PQL1
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
In Six-Year 2 ERA Data
1999-2004?
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL; only
one spike level
Yes, some data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Page 18
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Analyte
CASRN
Vinyl chloride
75-01-4
Xylenes (total)
1330-20-7
In Six-Year 1 Data?
Yes, no data < PQL
Yes, no data < PQL
In Six-Year 2 ERA Data
1999-2004?
Yes, some data < PQL
Yes, some data < PQL
Means passing rates for Six-Year 1 data were calculated for this report, as these analytes were not
evaluated in the March 2003 report, and acceptance criteria are percentage-based, not+ 2 S.D.
Means passing rates for Six-Year 1 data at or below the PQL could not be calculated for this report, as
these analytes were not evaluated in the March 2003 report, acceptance criteria are + 2 S.D., and
available regression coefficients are not valid at or below the PQL.
5.2 Calculating National Passing Rates
ERA provided national failure rates that were converted into passing rates by subtracting
the percent of laboratories failing from 100%. Six-Year 1 PT data for the 40 analytes that were
prioritized for analysis in the March 2003 report had been compiled (and passing rates
calculated) in 2003 from original printed output from participating laboratories and EPA
archives. In a few cases, some of the original data could not be used because the original hard
copies were not legible. For analytes that were evaluated in the March 2003 report, the passing
rates and true concentrations were taken directly from the report. In addition, passing rates were
calculated for analytes that were not prioritized for the 2003 Six-Year 1 PQL Assessment using
the Six-Year 1 data.
The Acceptance Criteria that were set forth in various FR notices during the time of the
generation of the Six-Year 1 data were used to calculate the passing rates. However, while this
was a relatively straightforward procedure for analytes with percentage-based acceptance criteria
(e.g., ą 30%), fourteen analytes have acceptance criteria of+2 standard deviations (SD) about
the estimated mean recovery for each PT study. The mean and acceptance criteria must be
calculated by using coefficients that were applicable during the generation of the Six-Year 1 PE
data; these coefficients are not available from EPA at this time. The equations are:
Mean = a*T + b
. SD = c*T + d
Where a, b, c, and d are the coefficients, and T is the true or spiked concentration.
Coefficients that were published by the NELAC in 2002 were available for this
assessment; however it is not clear whether these coefficients were in place during the generation
of the Six-Year 1 data. Re-calculation of passing rates for several of these analytes using the
2002 NELAC coefficients indicated considerable agreement in passing rates, although values
were different in some cases (there was no apparent pattern to the values that were not in
agreement). This suggested that the coefficients may not have changed or at least not changed
substantially from the 1990s to 2002; however this is uncertain. Since eight of the 14 analytes
with acceptance criteria of + 2 SD were evaluated in the March 2003 report, and acceptance
criteria had, apparently, been provided by EPA at that time, the Six-Year 1 regressions for these
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October 2009
eight analytes are taken directly from the data in the March 2003 report. These eight analytes
are: benzo(a)pyrene, di(2-ethylhexyl)phthalate, diquat, glyphosate, hexachlorobenzene,
hexachlorocyclopentadiene, oxamyl, and picloram. The remaining six of 14 analytes that had
not been prioritized for inclusion in the March 2003 report are: bromate, dalapon, di(2-
ethylhexyl)adipate, dinoseb, endothall, and simazine. Passing rates for these six analytes were
calculated using the 2002 NELAC coefficients. As a result, there is some uncertainty associated
with the Six-Year 1 PT data analysis for these six analytes.
It should be noted that for dalapon, di(2-ethylhexyl)adipate, endothall, and simazine,
passing rates for data below the PQL were not determined, as the 2002 NELAC criteria are only
valid over specific concentration ranges, and the ranges did not extend below the PQLs for these
analytes.
5.3 Regression Plots
The PQL assessments are illustrated using linear regressions that plot laboratory passing
rate versus true concentration. The PQL often has been set at the concentration where 75% of
laboratories are predicted to meet acceptance criteria. The number of laboratories that
participated in the Six-Year 1 PT studies for the regulated analytes ranged from approximately
10 to more than 60, with approximately 10 to 30 different concentrations evaluated. The number
of laboratories that participated in the ERA PT studies from 1999-2004 for the regulated analytes
ranged from approximately 10 to more than 70, with 59-60 different concentrations evaluated.
In cases where the acceptance criteria vary with concentration, the data points that were
less than 10 ng/L and those that were greater than or equal to 10 ng/L are plotted as independent
data populations, as the variable acceptance criteria tend to result in two "clusters" of data. The
following sections present the results of the regressions used in Six-Year 1, the regressions of the
1999-2004 ERA PT data, and any methods that have been approved for these analytes since
2000. The ERA data comprise approximately 50% of the nationwide PT data, while the PT data
used in Six-Year 1 was from state and EPA laboratories across the country. Several analytes in
Exhibit 1 could not be evaluated in this report for a number of reasons. These include:
Acrylamide: No PT data available.
Chlorite: Chlorite has no promulgated PQL.
Epichlorohydrin: No PT data available.
2,3,7,8-Tetrachlorodibenzodioxin (TCDD - dioxin): Only one data point in the ERA data
set, and no Six-Year 1 PT data.
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6.0 Results of PQL Assessment
EPA used two very different approaches to assess improvements in laboratory analytical
performance over time: 1) evaluating data from the laboratory accreditation studies performed
as part of the drinking water laboratory certification program (PE/PT data), and 2) comparing
performance of the analytical methods available for compliance monitoring at the time of
promulgation to those available currently. For analytes with no new methods, analytical
performance was measured solely by PE/PT data. For those analytes with new methods,
analytical performance was measured by PE/PT data, but may be supported by lower detection
limits from new methods. The existence of new methods with lower detection limits may not
directly translate to improved analytical performance, however. It is possible that only a small
number of laboratories will use a new method, or it may take time for the method to be utilized
to its full effectiveness.
Despite of using this two-step approach, EPA had difficulty in making a quantitative
assessment of the improvements in laboratory performance over time. There were severe
limitations in the laboratory accreditation studies data, i.e. PE/PT results were either not
available below the current PQL, the concentrations of interest, or the results were
inconclusive/inadequate regarding a potential to revise the PQL. As a result, EPA did not have
sufficient data to recalculate any PQLs with certainty. Instead, EPA used the data to indicate
potential (qualitative assessment) for PQL revision.
For each analyte, MDLs from EPA-approved methods are compared and a PQL
assessment is presented by means of linear regression of both the Six-Year 1 dataset and the
ERA dataset from Six-Year 2. Note that MDLs from proprietary methods (i.e., analytical
methods not developed by EPA) are not included in the MDL comparison, as they are not readily
available. A qualitative conclusion is drawn by presenting a recommendation of whether a PQL
might be reduced. The discussion includes an indication of whether an analyte was evaluated in
the March 2003 report (e.g., included for discussion, but PE data were not necessarily regressed),
whether the Six-Year 1 data were regressed in the March 2003 report (e.g., analyte was included
and the PE data were regressed), how the true concentrations relate to the PQL, and how the PE
data from Six-Year 1 and the ERA PT data from Six-Year 2 may suggest or not suggest potential
changes to the PQL.
The results for the regulated analytes are broken down into two categories based on the
limitation of the PQL for setting MCL at the time of promulgation: 1) analytes with Maximum
Contaminant Level (MCL) equal to the current PQL, and thus the PQL is limiting; or 2) analytes
with MCL greater than the current PQL and thus it is technically feasible to reduce an MCL.
PQL assessment for these analytes can indicate the potential for MCL reduction beyond the
current PQL. The PQL assessments were made and are presented in this report for a total of 66
analytes. Four analytes could not be analyzed for the reasons stated: acrylamide,
epichlorohydrin, 2,3,7,8-TCDD (dioxin) lacked PE/PT data, and chlorite has no PQL.
Using this as a framework, the following sub-categories are used to summarize the results
of PQL analysis. These categorizations were made based on a visual inspection of the
regressions. In some cases, even though the regression line(s) were above the 75% passing rate,
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several factors, including poor performance above the PQL or lack of data below the PQL led to
a conclusion that perhaps the PQL should not be reduced. In addition, consideration was given
to recent laboratory performance as indicated by the ERA data. For example, if the older Six-
Year 1 data indicated that the PQL should not be reduced, and if the more recent ERA data
indicated better performance, this was a factor in making the overall determination as to whether
or not a PQL could be reduced.
Analytes with MCL equal to the current PQL, and thus the PQL is limiting
PQL assessment supports reduction of the current PQL;
PQL assessment may support reduction of the current PQL; and
- PQL assessment does not support reduction of the current PQL, or data are
inconclusive or insufficient to reach a conclusion
Analytes with MCL greater than the current PQL and thus it is technically feasible to
reduce an MCL
PQL assessment supports reduction of the current PQL;
PQL assessment may support reduction of the current PQL; and
- PQL assessment does not support reduction of the current PQL, or data are
inconclusive or insufficient to reach a conclusion.
Note that the qualitative conclusions presented in this report are not necessarily identical
to the conclusions that were documented in the March 2003 report. Rather, a new assessment is
made herein considering the advantages and disadvantages of the PQL concept, the availability
of PT data in the vicinity of and/or below the PQL, and outliers. The qualitative conclusions are
based primarily on data that are in the vicinity of and/or below the PQL (for most of the VOCs,
this corresponds to concentrations <10 |ig/L). Only the current evaluations of the Six-Year 1 and
Six-Year 2/ERA data are presented in this report.
6.1 Analytes with Maximum Contaminant Level (MCL) Equal to the Current PQL and
Thus the PQL is limiting
Twenty-five analytes have an MCL that is set at the PQL. As a result, PQL assessment is
required to determine whether an MCL might be lowered in the future. These 25 analytes can be
further categorized into the three groups mentioned in Section 6.0 depending on whether or not
the PT assessments support the reduction of the current PQL.
6.1.1 PQL Assessment Supports Reduction of the Current PQL
Of the 25 analytes mentioned above, nine analytes have an existing PQL that is equal to
the MCL and their PE/PT data suggest that the PQL could be lower.
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Benzene
Results of the Methods Comparison
Exhibit 4 summarizes the MDLs for benzene as documented in EPA-developed analytical
methods. No updated or new analytical methods have been approved for the analysis of benzene
in drinking water samples during the years 2000-2007.
Exhibit 4: Analytical Methods for Benzene
MCL = 0.005 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01
0.03-0.04
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the POL Analysis
The current PQL for benzene is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 5). The Six-Year 1 PE data for benzene were regressed as
part of the March 2003 report. Note that the acceptance criteria are + 40% at spike
concentrations below 10 jig/L and + 20% at or above 10 u.g/L; hence the data are regressed as
two independent populations. Two of the 17 spike values from the Six-Year 1 data set are below
the current PQL of 5 |ig/L. Eight of the 60 spike values from the Six-Year 2/ERA data set are
less than the current PQL. All of the passing rates for the Six-Year 1 and Six-Year 2/ERA data
sets are at or above 75%.
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 5: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Benzene
O)
c
'in
in
n
a.
in
Ģ
o
5
o
.a
n
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
n -
^JA^ ^MT^ '
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
i ^Ŧ_. Vir^y^
v^*^ ,:
75%
Acceptance Criteria
= + 20%
10 15
True Value (ug/L)
20
25
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data At or Above 10 ug/L
PQL
-10 ug/L Acceptance Criteria Boundary
Conclusion for Benzene
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 ug/L for both the Six-Year 1 and Six-Year 2/ERA data sets suggest that the PQL could
be lower. Although there are limited Six-Year 1 data below the PQL, laboratory passing rates
below and in the vicinity of the PQL are well above 75%, which supports the conclusion that the
PQL could be lower. No new or revised methods that may be expected to improve analytical
performance in the vicinity of the current PQL (and hence suggest possible reduction of the
PQL) have been approved from 2000-2007.
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EPA815-B-09-003
October 2009
Carbon Tetrachloride
Results of the Methods Comparison
Exhibit 6 summarizes the MDLs for carbon tetrachloride as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of carbon tetrachloride in drinking water samples during the years 2000-2007.
Exhibit 6: Analytical Methods for Carbon Tetrachloride
MCL = 0.005 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
551.1
Technique
CCGCwithPID/ELCD
CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.01 -0.02
0.08-0.21
0.002 -
0.050
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for carbon tetrachloride is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA
data sets are regressed separately (see Exhibit 7). The Six-Year 1 PE data for carbon
tetrachloride were evaluated but were not regressed as part of the March 2003 report. Note that
the acceptance criteria are + 40% at spike concentrations below 10 |ig/L and + 20% at or above
10 |ig/L; hence the data are regressed as two independent populations. One of the 17 spike
values from the Six-Year 1 data set is below the current PQL of 5 |ig/L. Nine of the 60 Six-Year
2/ERA spike values are below the current PQL. Nearly all of the passing rates for the Six-Year 1
and Six-Year 2/ERA data sets are above 75% (with the exception of two Six-Year 2/ERA
passing rates).
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EPA815-B-09-003
October 2009
Exhibit 7: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Carbon Tetrachloride
S
100
8 eo H
s.
8 so H
40 -
30 -
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
75%
Acceptance Criteria
= + 20%
3 10 12
True Value (ug/L)
14
16
18
20
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data Ator Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for Carbon Tetrachloride
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 ug/L for both the Six-Year 1 and Six-Year 2/ERA data sets suggest that the PQL could
be lower. Although there is only one Six-Year 1 datum below the PQL, laboratory passing rates
below and in the vicinity of the PQL are well above 75%, which supports the conclusion that the
PQL could be lower. No new or revised methods that may be expected to improve analytical
performance in the vicinity of the current PQL (and hence suggest possible reduction of the
PQL) have been approved from 2000-2007.
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Chlordane
Results of the Methods Comparison
Exhibit 8 summarizes the MDLs for chlordane as documented in EPA-developed
analytical methods (note that the MDLs in Exhibit 8 represent ranges for chlordane, a-chlordane,
y-chlordane, c/'s-nonachlor and trans-nonachlof). No updated or new analytical methods have
been approved for the analysis of chlordane in drinking water samples during the years 2000-
2007.
Exhibit 8: Analytical Methods for Chlordane
MCL = 0.002 mg/L Current PQL = 0.002 mg/L DL = 0.0002 mg/L
Acceptance Criteria = + 45%
EPA Methods Approved for the Analysis of Drinking Water
Method
505
508
508.1
525.2
Technique
ME and GC
GC/ECD
LSE and ECGC
LSE and CCGC/MS
MDL ug/L
0.006-0.14
0.0016-
0.0041
0.001 -
0.004
0.05-0.22
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141 .24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the PQL Analysis
The current PQL for chlordane is 2 u.g/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 9). The Six-Year 1 PE data for chlordane were evaluated in
the March 2003 report; however, these data were not regressed in the report. Three of the 20
spike values from the Six-Year 1 data set are below the current PQL of 2 |ig/L. No Six-Year
2/ERA data are below the current PQL. All of the Six-Year 1 passing rates and all but two of the
Six-Year 2/ERA passing rates exceed 75%.
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EPA 81 5-B-09-003
October 2009
Exhibit 9: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Chlordane
100
1/1
in
ra
a.
in
at
Ģ
2
o
ra
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 45%
Current PQL
= 2 ug/L
3 10 12
True Value (ug/L)
14
16
18
20
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Chlordane
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 |ig/L for the Six-Year 1 data set suggest that the PQL could be lower. Although there
are no Six-Year 2/ERA data below the PQL, laboratory passing rates in the vicinity of the PQL
are well above 75% which may support the Six-Year 1 data conclusion that the PQL could be
lower. No new or revised methods that may be expected to improve analytical performance in
the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
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1,2-Dichloroethane (Ethylene dichloride)
Results of the Methods Comparison
Exhibit 10 summarizes the MDLs for 1,2-dichloroethane as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of 1,2-dichloroethane in drinking water samples during the years 2000-2007.
Exhibit 10: Analytical Methods for 1,2-Dichloroethane
MCL = 0.005 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.03
0.02-0.06
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the POL Analysis
The current PQL for 1,2-dichloroethane is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA
data sets are regressed separately (see Exhibit 11). The Six-Year 1 PE data for 1,2-
dichloroethane were evaluated but were not regressed as part of the March 2003 report. Note
that the acceptance criteria are + 40% at spike concentrations below 10 jig/L and + 20% at or
above 10 u.g/L; hence the data are regressed as two independent populations. One of the 17
spike values from the Six-Year 1 data set is below the current PQL of 5 |ig/L. Seven of the 60
Six-Year 2/ERA spike values are below the current PQL. All of the passing rates for the Six-
Year 1 and Six-Year 2/ERA data are above 75%.
Page 29
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 11: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,2-Dichloroethane
90
80 -
70 -
O)
1 6°-
ro
Q.
1 50-
|
| 4°~
s? 3°-
20 -
10 -
; ŧ*.
1
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
B m
.. ' ^SiT^^^^
75%
Acceptance Criteria
= + 20%
3 10 12
True Value (ug/L)
14
16
18
20
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data Ator Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for 1,2-Dichloroethane
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 |ig/L for both the Six-Year 1 and Six-Year 2/ERA data sets suggest that the PQL could
be lower. Although there is only one Six-Year 1 datum below the PQL, laboratory passing rates
below and in the vicinity of the PQL are well above 75%, which supports the conclusion that the
PQL could be lower. No new or revised methods that may be expected to improve analytical
performance in the vicinity of the current PQL (and hence suggest possible reduction of the
PQL) have been approved from 2000-2007.
30
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
1,2-Dichloropropane
Results of the Methods Comparison
Exhibit 12 summarizes the MDLs for 1,2-dichloropropane as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of 1,2-dichloropropane in drinking water samples during the years 2000-2007.
Exhibit 12: Analytical Methods for 1,2-Dichloropropane
MCL = 0.005 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01 -0.03
0.02-0.04
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the POL Analysis
The current PQL for 1,2-dichloropropane is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA
data sets are regressed separately (see Exhibit 13). The Six-Year 1 PE data for 1,2-
dichloropropane were evaluated but were not regressed as part of the March 2003 report. Note
that the acceptance criteria are + 40% at spike concentrations below 10 jig/L and + 20% at or
above 10 u.g/L; hence the data are regressed as two independent populations. No Six-Year 1 data
are available below the current PQL of 5 |ig/L. Nine of the 60 spike values in the Six-Year
2/ERA data set are below the current PQL. All of the passing rates are above 75% (with the
exception of one passing rate equal to 75%).
Page 31
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 13: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,2-Dichloropropane
O)
_c
'in
in
ra
a.
in
01
c
S
2
o
.a
ra
100
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
75%
Acceptance Criteria
= + 20%
3 10 12
True Value (ug/L)
14 16 18 20
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data Ator Above 10 ug/L
Six-Year 1 Data Ator Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for 1,2-Dichloropropane
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 ug/L for the Six-Year 2/ERA data set suggests that the PQL could be lower. Although
there are no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL
are well above 75% which may support the Six-Year 2/ERA data conclusion that the PQL could
be lower. No new or revised methods that may be expected to improve analytical performance
in the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
Page 32
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Hexachlorobenzene
Results of the Methods Comparison
Exhibit 14 summarizes the MDLs for hexachlorobenzene as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of hexachlorobenzene in drinking water samples during the years 2000-2007.
Exhibit 14: Analytical Methods for Hexachlorobenzene
MCL = 0.001 mg/L Current PQL = 0.001 mg/L DL = 0.0001 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
505
508
508.1
525.2
551.1
Technique
ME and GC
GC/ECD
L/S Extraction and ECGC
LSE and CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.002
0.0077
0.001
0.049-0.13
0.001 -
0.003
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141 .24(h)(19)(i)(B).
Results of the PQL Analysis
The current PQL for hexachlorobenzene is 1 |ig/L. The Six-Year 1 and Six-Year 2/ERA
data sets are regressed separately (see Exhibit 15). The Six-Year 1 PE data for
hexachlorobenzene were evaluated but were not regressed as part of the March 2003 report.
Eight of the 14 spike Six-Year 1 values are below the current PQL of 1 |ig/L. Nine of the 60
Six-Year 2/ERA spike values are below the current PQL. Nearly all of the passing rates for the
Six-Year 1 and Six-Year 2/ERA hexachlorobenzene data are above 75% (with the exception of
two Six-Year 2/ERA passing rates).
Page 33
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 15: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Hexachlorobenzene
O
.a
ra
100
90 -
70 -
O)
I 60
ro
a.
a! so
c
Ģ
ra
40 -
30 -
20 -
10 -
At1
75%
Acceptance Criteria
= Mean + 2 SD
Current PQL
= 1 ug/L
0.0 0.5 1.0 1.5 2.0 2.5
True Value (ug/L)
3.0
4.0
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Hexachlorobenzene
The high laboratory passing rates (generally well above 75%) at concentrations below
and in the vicinity of the current PQL of 1 |ig/L for both the Six-Year 1 and Six-Year 2/ERA
data sets suggest that the PQL could be lower. No new or revised methods that may be expected
to improve analytical performance in the vicinity of the current PQL (and hence suggest possible
reduction of the PQL) have been approved from 2000-2007.
Page 34
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Tetrachloroethylene
Results of the Methods Comparison
Exhibit 16 summarizes the MDLs for tetrachloroethylene as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of tetrachloroethylene in drinking water samples during the years 2000-2007.
Exhibit 16: Analytical Methods for Tetrachloroethylene
MCL = 0.005 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
551.1
Technique
CCGCwithPID/ELCD
CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.02-0.05
0.05-0.14
0.002 -
0.008
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for tetrachloroethylene is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA
data sets are regressed separately (see Exhibit 17). The Six-Year 1 PE data for
tetrachloroethylene were evaluated but were not regressed as part of the March 2003 report.
Note that the acceptance criteria are + 40% at spike concentrations below 10 |ig/L and + 20% at
or above 10 |ig/L; hence the data are regressed as two independent populations. No Six-Year 1
data are available below the current PQL of 5 u.g/L. Thirteen of the 60 spike values in the Six-
Year 2/ERA data set are below the current PQL. All but two of the passing rates are above 75%.
Furthermore, the regression lines are also well above 75%.
Page 35
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 17: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Tetrachloroethylene
n
in
ra
a.
in
o
.a
100
90 -
80 -
70 -
50 -
40 -
30 -
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
75%
Acceptance Criteria
= + 20%
3 10 12
True Value (ug/L)
16
18
20
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data At or Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for Tetrachloroethylene
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 |ig/L for the Six-Year 2/ERA data set suggests that the PQL could be lower. Although
there are no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL
are well above 75% which may support the Six-Year 2/ERA data conclusion that the PQL could
be lower. No new or revised methods that may be expected to improve analytical performance
in the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
36
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
1,1,2- Trichloroethane
Results of the Methods Comparison
Exhibit 18 summarizes the MDLs for 1,1,2-trichloroethane as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of 1,1,2-trichloroethane in drinking water samples during the years 2000-2007.
Exhibit 18: Analytical Methods for l,l?2-Trichloroethane
MCL = 0.005 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
551.1
Technique
CCGCwithPID/ELCD
CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.04
0.03-0.10
0.012-
0.017
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the POL Analysis
The current PQL for 1,1,2-trichloroethane is 5 |ig/L. The Six-Year 1 and Six-Year
2/ERA data sets are regressed separately (see Exhibit 19). The Six-Year 1 PE data for 1,1,2-
trichloroethane were evaluated but were not regressed as part of the March 2003 report. Note
that the acceptance criteria are + 40% at spike concentrations below 10 jig/L and + 20% at or
above 10 u.g/L; hence the data are regressed as two independent populations. No Six-Year 1 data
are available below the current PQL of 5 |ig/L. Twelve of the 60 spike values in the Six-Year
2/ERA data are below the current PQL. All of the passing rates are above 75%.
Page 37
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 19: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,1,2-Trichloroethane
100
90 -
80 -
70 -
ro
Q.
I 50
&
ra
40 ^
30 i
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
' -__j^LJ^^
75%
Acceptance Criteria
= + 20%
Conclusion for 1,1,2-Trichloroethane
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 ug/L for the Six-Year 2/ERA data set suggests that the PQL could be lower. Although
there are no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL
are well above 75% which may support the Six-Year 2/ERA data conclusion that the PQL could
be lower. No new or revised methods that may be expected to improve analytical performance
in the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
38
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Trichloroethylene
Results of the Methods Comparison
Exhibit 20 summarizes the MDLs for trichloroethylene as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of trichloroethylene in drinking water samples during the years 2000-2007.
Exhibit 20: Analytical Methods for Trichloroethylene
MCL = 0.005 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
551.1
Technique
CCGCwithPID/ELCD
CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.01 -0.06
0.02-0.19
0.002 -
0.042
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for trichloroethylene is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA
data sets are regressed separately (see Exhibit 21). The Six-Year 1 PE data for trichloroethylene
were evaluated but were not regressed as part of the March 2003 report. Note that the
acceptance criteria are + 40% at spike concentrations below 10 |ig/L and + 20% at or above 10
u.g/L; hence the data are regressed as two independent populations. No Six-Year 1 data are
below the current PQL of 5 u.g/L. Six of the 60 spike values in the Six-Year 2/ERA data are
below the current PQL. All but one of the passing rates are above 75%. Furthermore, the
regression lines are also well above 75%.
39
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 21: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Trichloroethylene
O)
_c
'in
in
ra
a.
in
o
2
Z
o
&
ra
100
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
75%
Acceptance Criteria
= + 20%
3 10 12
True Value (ug/L)
14
16
18
20
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
75% Passing Rate
ERADataAtor Above 10 ug/L
Six-Year 1 Data Ator Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for Trichloroethylene
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 ug/L for the Six-Year 2/ERA data set suggests that the PQL could be lower. Although
there are no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL
are well above 75% which may support the Six-Year 2/ERA data conclusion that the PQL could
be lower. No new or revised methods that may be expected to improve analytical performance
in the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
Page 40
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
6.1.2 PQL Assessment May Support Reduction of the Current PQL
Of the 25 analytes mentioned in Section 6.1, eight analytes have an existing PQL that is
equal to the MCL and their PE/PT data suggest that the PQL could possibly be lower.
Alachlor
Results of the Methods Comparison
Exhibit 22 summarizes the MDLs for alachlor as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of alachlor in drinking water samples during the years 2000-2007.
Exhibit 22: Analytical Methods for Alachlor
MCL = 0.002 mg/L Current PQL = 0.002 mg/L DL =
Acceptance Criteria = + 45%
= 0.0002 mg/L
EPA Methods Approved for the Analysis of Drinking Water
Method
505
507
508.1
525.2
551.1
Technique
ME and GC
GC/N-PD
LSE and ECGC
LSE and CCGC/MS
LLE/GC w/ ECD
Notes: Regulatory DLs for synthetic organic compounds are listed at
Acceptance Criteria for synthetic organic compounds are listed at 40
MDL ug/L
0.225
0.14
0.009
0.069-0.16
0.005 -
0.025
40CFR141.24(h)(18).
CFR141.24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for alachlor is 2 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 23). The Six-Year 1 PE data for alachlor were evaluated in
the March 2003 report; however, these data were not regressed in that report. Four of the 20
spike values from the Six-Year 1 data set are below the current PQL of 2 |ig/L. However, none
of the Six-Year 2/ERA data are below the current PQL. The percentage of laboratories passing
is variable, ranging from 71.4% to 100%. The Six-Year 1 passing rates generally exceed 75%
(with the exception of one spike value) and all of the Six-Year 2/ERA passing rates are greater
than or equal to 75%.
Page 41
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 23: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Alachlor
O)
_c
'in
in
ra
a.
in
o
2
2
o
100
90 -
80
70
60 -
50 -
40 -
30 -
20 -
10 -
I
75%
Acceptance Criteria
= + 45%
Current PQL
= 2 ug/L
3 10 12
True Value (ug/L)
16
18
20
ERA Data
PQL
Six-Year 1 Data
75% Passing Rate
Conclusion for Alachlor
The Six-Year 1 laboratory passing rates below and in the vicinity of the PQL of 2 |ig/L
are above 75% with one exception. Given the lack of Six-Year 2/ERA data below the PQL, but
passing rates above 75% in the vicinity of the PQL, a reduction of the PQL may be considered.
No new or revised methods that may be expected to improve analytical performance in the
vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
Page 42
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Antimony
Results of the Methods Comparison
Exhibit 24 summarizes the MDLs for antimony as documented in EPA-developed
analytical methods. Updates to two methods have been approved for the analysis of antimony in
drinking water samples during the years 2000-2007 (see Exhibit A-l). These updates are
associated with administrative and technical changes or clarifications that are not expected to
improve analytical performance near the PQL.
Exhibit 24: Analytical Methods for Antimony
MCL = 0.006 mg/L Current PQL = 0.006 mg/L DL = 0.0004-0. 003mg/L
Acceptance Criteria = +30%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.8
200.9
Technique
ICP/MS
GFAA
MDL mg/L
0.00002 -
0.0004
0.0008
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the PQL Analysis
The current PQL for antimony is 0.006 mg/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 25). The Six-Year 1 PE data for antimony were not
evaluated in the March 2003 report. Two of the 20 spike values from the Six-Year 1 data are
below the current PQL of 0.006 mg/L. No Six-Year 2/ERA data are below the current PQL. All
of the passing rates in both data sets exceed 75%. The regression lines are also well above 75%.
Page 43
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 25: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Antimony
in
ra
a.
in
at
Ģ
2
o
ra
80
70 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 30%
Current PQL
= 0.006 mg/L
0.00
0.02
0.04 0.06
True Value (mg/L)
0.08
0.10
0.12
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Antimony
Given the availability of limited data below the current PQL of 0.006 mg/L, but relatively
high laboratory passing rates (above 75%) just below and in the vicinity of the PQL for the Six-
Year 1 data, and above 75% passing rates in the vicinity of the PQL for the Six-Year 2/ERA
data, a reduction of the PQL may be considered. No new or revised methods that may be
expected to improve analytical performance in the vicinity of the current PQL (and hence
suggest possible reduction of the PQL) have been approved from 2000-2007.
Page 44
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
1,2-Dibromo-3-chloropropane (DBCP)
Results of the Methods Comparison
Exhibit 26 summarizes the MDLs for l,2-dibromo-3-chloropropane as documented in
EPA-developed analytical methods. No updated or new analytical methods have been approved
for the analysis of DBCP in drinking water samples during the years 2000-2007.
Exhibit 26: Analytical Methods for DBCP
MCL = 0.0002 mg/L Current PQL = 0.0002 mg/L DL = 0.00002 mg/L
Acceptance Criteria = + 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
504.1
551.1
Technique
ME and GC
LLE/GC w/ ECD
MDL ug/L
0.01
0.006 -
0.009
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141 .24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the POL Analysis
The current PQL for DBCP is 0.2 ug/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 27). The Six-Year 1 PE data for DBCP were evaluated but
were not regressed as part of the March 2003 report. One of the 14 spike values from the Six-
Year 1 data is below the current PQL of 0.2 u.g/L. Three of the 60 Six-Year 2/ERA spike values
are below the current PQL. All of the passing rates for the Six-Year 1 and Six-Year 2/ERA data
are above 75%.
Page 45
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 27: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - DBCP
n
in
ra
a.
in
o
2
2
o
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0.0
^
75%
Acceptance Criteria
= + 40%
Current PQL
= 0.2 ug/L
0.5
1.0 1.5
True Value (ug/L)
2.0
2.5
3.0
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for l,2-Dibromo-3-chloropropane
Given the limited data below the current PQL of 0.2 |ig/L but high laboratory passing
rates (well above 75%) just below and in the vicinity of the PQL for both Six-Year 2/ERA and
Six-Year 1 data set, a reduction of the PQL may be considered. No new or revised methods that
may be expected to improve analytical performance in the vicinity of the current PQL (and hence
suggest possible reduction of the PQL) have been approved from 2000-2007.
Page 46
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Heptachlor
Results of the Methods Comparison
Exhibit 28 summarizes the MDLs for heptachlor as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of heptachlor in drinking water samples during the years 2000-2007.
Exhibit 28: Analytical Methods for Heptachlor
MCL = 0.0004 mg/L Current PQL = 0.0004 mg/L DL = 0.00004 mg/L
Acceptance Criteria = + 45%
EPA Methods Approved for the Analysis of Drinking Water
Method
505
508
508.1
525.2
551.1
Technique
ME and GC
GC/ECD
LSE and ECGC
LSE and CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.003
0.0015
0.005
0.059-0.15
0.002 -
0.081
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141 .24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the PQL Analysis
The current PQL for heptachlor is 0.4 |ig/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 29). The Six-Year 1 PE data for heptachlor were
evaluated but were not regressed as part of the March 2003 report. Three of the 19 spike values
in the Six-Year 1 data set are below the current PQL of 0.4 |ig/L. None of the Six-Year 2/ERA
data are below the current PQL. Although all of the Six-Year 1 passing rates, along with both
regression lines, are well above 75%, the Six-Year 2/ERA passing rates display significant
variability. Furthermore, three of the Six-Year 2/ERA passing rates are below 75%.
Page 47
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 29: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Heptachlor
n
in
ra
a.
in
o
2
2
o
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 45%
Current PQL
= 0.4ug/L
0.0 0.5 1.0 1.5 2.0 2.5 3.0
True Value (ug/L)
3.5
4.0
4.5
5.0
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Heptachlor
Given the availability of limited data below the current PQL of 0.4 |ig/L, but relatively
high laboratory passing rates (well above 75%) below and in the vicinity of the PQL for the Six-
Year 1 data, and a lack of data below the PQL for the Six-Year 2/ERA data, a reduction of the
PQL may be considered. The passing rates in the vicinity of the PQL for the Six-Year 2/ERA
data are variable which may not support the Six-Year 1 data conclusion that the PQL might be
reduced. No new or revised methods that may be expected to improve analytical performance in
the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
Page 48
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Heptachlor Epoxide
Results of the Methods Comparison
Exhibit 30 summarizes the MDLs for heptachlor epoxide as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of heptachlor epoxide in drinking water samples during the years 2000-2007.
Exhibit 30: Analytical Methods for Heptachlor Epoxide
MCL = 0.0002 mg/L Current PQL = 0.0002 mg/L DL = 0.00002 mg/L
Acceptance Criteria = + 45%
EPA Methods Approved for the Analysis of Drinking Water
Method
505
508
508.1
525.2
551.1
Technique
ME and GC
GC/ECD
LSE and ECGC
LSE and CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.004
0.0059
0.001
0.048-0.13
0.002 -
0.202
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141 .24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the PQL Analysis
The current PQL for heptachlor epoxide is 0.2 |ig/L. The Six-Year 1 and Six-Year
2/ERA data sets are regressed separately (see Exhibit 31). The Six-Year 1 PE data for
heptachlor epoxide were evaluated but were not regressed as part of the March 2003 report.
Three of the 19 spike values in the Six-Year 1 data are below the current PQL of 0.2 |ig/L. None
of the Six-Year 2/ERA data are below the current PQL. Although all of the Six-Year 1 passing
rates, along with both regression lines, are well above 75%, the Six-Year 2/ERA passing rates
displayed significant variability. Furthermore, two of the Six-Year 2/ERA passing rates near the
PQL are below 75%.
Page 49
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 31: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Heptachlor Epoxide
in
ra
a.
in
3
Ģ
o
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0
75%
Acceptance Criteria
= + 45%
Current PQL
= 0.2 ug/L
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
True Value (ug/L)
5.0
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Heptachlor Epoxide
Given the availability of limited data below the current PQL of 0.2 |ig/L, but relatively
high laboratory passing rates (mostly >90%) below and in the vicinity of the PQL for the Six-
Year 1 data, and a lack of data below the PQL for the Six-Year 2/ERA data, a reduction of the
PQL may be considered. The passing rates in the vicinity of the PQL for the Six-Year 2/ERA
data are highly variable which may not support the Six-Year 1 data conclusion that the PQL
might be reduced. No new or revised methods that may be expected to improve analytical
performance in the vicinity of the current PQL (and hence suggest possible reduction of the
PQL) have been approved from 2000-2007.
50
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Lindane
Results of the Methods Comparison
Exhibit 32 summarizes the MDLs for lindane as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of lindane in drinking water samples during the years 2000-2007.
Exhibit 32: Analytical Methods for Lindane
MCL = 0.0002 mg/L Current PQL = 0.0002 mg/L DL = 0.00002 mg/L
Acceptance Criteria = + 45%
EPA Methods Approved for the Analysis of Drinking Water
Method
505
508
508.1
525.2
551.1
Technique
ME and GC
GC/ECD
LSE and ECGC
LSE and CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.003
0.006
0.006
0.047-0.15
0.002 -
0.017
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141 .24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the PQL Analysis
The current PQL for lindane is 0.2 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 33). The Six-Year 1 PE data for lindane were not evaluated
in the March 2003 report. Three of the 20 spike values in the Six-Year 1 data set are less than or
equal to the current PQL of 0.2 |ig/L. None of the Six-Year 2/ERA data are below the current
PQL. All the passing rates in both data sets are above 75%. Furthermore, the regression lines
are also well above 75%.
Page 51
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 33: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Lindane
n
in
ra
a.
in
o
2
2
o
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 45%
Current PQL
= 0.2 ug/L
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
True Value (ug/L)
4.0
4.5
5.0
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Lindane
Given the availability of limited data below the current PQL of 0.2 |ig/L, but relatively
high laboratory passing rates (well above 75%) below and in the vicinity of the PQL for the Six-
Year 1 data, and a lack of data below the PQL for the Six-Year 2/ERA data, a reduction of the
PQL may be considered. The passing rates in the vicinity of the PQL for the Six-Year 2/ERA
data are somewhat variable, but all above 75%, which may support the Six-Year 1 data
conclusion that the PQL might be reduced. No new or revised methods that may be expected to
improve analytical performance in the vicinity of the current PQL (and hence suggest possible
reduction of the PQL) have been approved from 2000-2007.
Page 52
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Toxaphene
Results of the Methods Comparison
Exhibit 34 summarizes the MDLs for toxaphene as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of toxaphene in drinking water samples during the years 2000-2007.
Exhibit 34: Analytical Methods for Toxaphene
MCL = 0.003 mg/L Current PQL = 0.003 mg/L DL
Acceptance Criteria = + 45%
= 0.001 mg/L
EPA Methods Approved for the Analysis of Drinking Water
Method
505
508
508.1
525.2
Technique
ME and GC
GC/ECD
LSE and ECGC
LSE and CCGC/MS
Notes: Regulatory DLs for synthetic organic compounds are listed at
Acceptance Criteria for synthetic organic compounds are listed at 40
MDL ug/L
1.0
Listed in
Method; no
MDLs
determined
0.13
1.0-1.7
40CFR141.24(h)(18).
CFR141.24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for toxaphene is 3 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 35). The Six-Year 1 PE data for toxaphene were evaluated
but were not regressed in the March 2003 report. Three of the 20 spike values in the Six-Year 1
data set are less than the current PQL of 3 |ig/L. None of the Six-Year 2/ERA data are below the
current PQL. All of the Six-Year 1 passing rates and regression line are well above 75%.
Although the Six-Year 2/ERA data display some variability (and two of the passing rates are
below 75%), the regression line is well above the 75% threshold.
Page 53
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 35: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Toxaphene
100
O)
_c
'in
in
ra
a.
in
01
c
S
o
&
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
f
75%
Acceptance Criteria
= + 45%
Current PQL
= 3 ug/L
3 10 12
True Value (ug/L)
14
16 18
20
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Toxaphene
Given the availability of limited data below the current PQL of 3 |ig/L, but relatively
high laboratory passing rates (well above 75%) below and in the vicinity of the PQL for the Six-
Year 1 data, and a lack of data below the PQL for the Six-Year 2/ERA data, a reduction of the
PQL may be considered. The passing rates in the vicinity of the PQL for the Six-Year 2/ERA
data are somewhat variable but all above 75%, which may support the Six-Year 1 data
conclusion that the PQL might be reduced. No new or revised methods that may be expected to
improve analytical performance in the vicinity of the current PQL (and hence suggest possible
reduction of the PQL) have been approved from 2000-2007.
Page 54
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Vinyl Chloride
Results of the Methods Comparison
Exhibit 36 summarizes the MDLs for vinyl chloride as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of vinyl chloride in drinking water samples during the years 2000-2007.
Exhibit 36: Analytical Methods for Vinyl Chloride
MCL= 0.002 mg/L Current PQL = 0.002 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01 -0.18
0.04-0.17
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for vinyl chloride is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 37). The Six-Year 1 PE data for vinyl chloride were
evaluated but were not regressed as part of the March 2003 report. No Six-Year 1 data are
available below the current PQL of 5 |ig/L. Two of the 60 spike values in the Six-Year 2/ERA
data are below the current PQL (a third is equal to the PQL). All of the passing rates are above
75% (with the exception of one passing rate that is equal to 75%). Furthermore, the regression
lines are well above 75%.
55
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 37: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Vinyl Chloride
100 -
90 -
80 -
70 -
O)
1 6°-
ro
Q.
8 50 i
S
Ģ
o
&
ra
40 -
30 -
20 -
10 -
I
.vo . *
75%
Acceptance Criteria
= + 40%
Current PQL
= 2 ug/L
10
15 20
True Value (ug/L)
25
30
35
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Vinyl Chloride
Given the availability of limited data below the current PQL of 2 |ig/L, but relatively
high laboratory passing rates (well above 75%) below and in the vicinity of the PQL for the Six-
Year 2/ERA data, and a lack of data below the PQL for the Six-Year 1 data, a reduction of the
PQL may be considered. The passing rates in the vicinity of the PQL for the Six-Year 1 data are
variable, but all are >75%, which may support the Six-Year 2/ERA data conclusion that the PQL
might be reduced. No new or revised methods that may be expected to improve analytical
performance in the vicinity of the current PQL (and hence suggest possible reduction of the
PQL) have been approved from 2000-2007.
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
6.1.3 PQL Assessment Does Not Support Reduction of the Current PQL or Data are
Insufficient to Reach a Conclusion.
Of the 25 analytes mentioned in Section 6.1, eight analytes have an existing PQL that is
equal to the MCL and their PE/PT data either indicate that the PQL should not be lower or their
PE/PT data are insufficient to reach a conclusion.
Benzo(a)pyrene
Results of the Methods Comparison
Exhibit 38 summarizes the MDLs for benzo(a)pyrene as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of benzo(a)pyrene in drinking water samples during the years 2000-2007.
Exhibit 38: Analytical Methods for Benzo(a)pyrene
MCL = 0.0002 mg/L Current PQL = 0.0002 mg/L DL = 0.00002 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
525.2
550
550.1
Technique
LSE and CCGC/MS
LLE/HPLC w/ CUV and FD
LSE/HPLC w/ CUV and FD
MDL ug/L
0.032-0.23
0.029
0.016
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141.24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for benzo(a)pyrene is 0.2 |ig/L. The Six-Year 1 and Six-Year 2/ERA
data sets are regressed separately (see Exhibit 39). The Six-Year 1 PE data for benzo(a)pyrene
were regressed as part of the March 2003 report. None of the Six-Year 1 or the Six-Year 2/ERA
data set are below the current PQL of 0.2 |ig/L. All of the passing rates in the Six-Year 1 data
are above 75% while several passing rates in the Six-Year 2/ERA data are less than or equal to
75%.
57
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 39: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Benzo(a)pyrene
100
90 -
80 -
70 -
ro
a.
8 50 4
S
Ģ
o
&
ra
40 -
30 -
20 -
10 -
0.0
75%
Acceptance Criteria
= Mean + 2 SD
Current PQL
= 0.2 ug/L
0.5
1.0 1.5 2.0
True Value (ug/L)
2.5
3.0
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Benzo(a)pyrene
Although the laboratory passing rates for the Six-Year 1 data set are above 75%, the
passing rates for the Six-Year 2/ERA data set are low in the vicinity of the PQL of 0.2 |ig/L. It
may not be appropriate to recommend lowering of the PQL due to the lack of data below the
current PQL for both data sets and the variability of the Six-Year 2/ERA passing rates. No new
or revised methods that may be expected to improve analytical performance in the vicinity of the
current PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-
2007.
Page 58
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Bromate
Results of the Methods Comparison
Exhibit 40 summarizes the MDLs for bromate as documented in EPA-developed
analytical methods. Four new analytical methods have been approved for the analysis of
bromate in drinking water samples during the years 2000-2007 (EPA Methods 317.0 (Rev. 2.0),
321.8, 326.0, and ASTM D6581-00 [Federal Register, Vol. 71, No. 2, p. 388, January 4, 2006;
see Exhibit A-l]). The MDLs/DLs for bromate by EPA Methods 317.0, 321.8 and 326.0 are
lower than those for EPA Method 300.1, suggesting that laboratory performance at low
concentrations may improve through use of Methods 317.0, 321.8 and 326.0. Since the new
ASTM method is proprietary, it is uncertain whether new MDLs may be lower than those for
other methods. Note that the acceptance criteria for bromate are given as +2 SD. NELAC
changed the acceptance criteria to +30% in March 2007, but +2 SD were in place during the
generation of the PT data used in this report.
Exhibit 40: Analytical Methods for Bromate
MCL = 0.01 0 mg/L Current PQL = 0.01 mg/L DL = N/A
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
300.1
317.0
321.8
326.0
Technique
1C
1C with postcolumn reagent
IC/ICP/MS
1C with suppressor acidified postcolumn reagent
MDL mg/L
0.00128-
0.00144
0.00012-
0.00098
0.0003 (DL)
0.00017-
0.0012 (DL)
Notes: EPA has not provided a regulatory DL for bromate in the CFR. Acceptance Criteria for
disinfection byproducts are listed at 40 CFR 141.1 31 (b)(2)(ii). As of April 1, 2007, the
Acceptance Criteria for bromate were changed to + 30% (71 FR 388 1/4/2006).
Results of the POL Analysis
The current PQL for bromate 10 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets are
regressed separately (see Exhibit 41). The Six-Year 1 PE data for bromate were not evaluated in
the March 2003 report. Three of the nine spike values in the Six-Year 1 data set are below the
current PQL of 10 |ig/L. One of the 60 spike values in the Six-Year 2/ERA data set is below the
PQL. Three of the Six-Year 1 concentrations and two of the Six-Year 2/ERA concentrations
have passing rates of less than 75%.
Page 59
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 41: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Bromate
100
in
ra
0.
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= Mean + 2 SD
Current PQL
= 10 ug/L
10
20
30
40
50
60
True Value (ug/L)
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Bromate
Although many of the laboratory passing rates for both the Six-Year 1 and Six-Year
2/ERA data sets are >75%, it may not be appropriate to recommend lowering of the PQL due to
the low passing rates below the current PQL of 10 |ig/L for the Six-Year 1 data set and the
variability of the Six-Year 2/ERA data set in the vicinity of the PQL. However, the approval of
EPA Methods 317.0 (Rev. 2.0) and 326.0 for the analysis of bromate provides lower MDLs that
were achievable by use of other approved methods. This may lead to an overall improvement in
analytical performance in the vicinity of the current PQL and could suggest possible reduction of
the PQL.
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Dichloromethane (Methylene chloride)
Results of the Methods Comparison
Exhibit 42 summarizes the MDLs for dichloromethane as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of dichloromethane in drinking water samples during the years 2000-2007.
Exhibit 42: Analytical Methods for Dichloromethane
MCL = 0.005 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01 -0.02
0.03-0.09
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the POL Analysis
The current PQL for dichloromethane is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA
data sets are regressed separately (see Exhibit 43). The Six-Year 1 PE data for dichloromethane
were evaluated but not regressed in the March 2003 report. Note that the acceptance criteria are
+ 40% at spike concentrations below 10 jig/L and + 20% at or above 10 u.g/L; hence the data are
regressed as two independent populations. None of the Six-Year 1 or the Six-Year 2/ERA data
are below the current PQL of 5 |ig/L. All but one of the passing rates in the Six-Year 1 data are
above 75%. Two of the passing rates in the Six-Year 2/ERA data are equal to 75%.
61
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 43: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Dichloromethane
100 -
ra
a.
in
.g
&
2
o
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
v.-^- ^--^
75%
Acceptance Criteria
= + 20%
3 10 12
True Value (ug/L)
16
18
20
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data Ator Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for Dichloromethane
Although most laboratory passing rates for both the Six-Year land Six-Year 2/ERA data
sets are high (well above 75%) in the vicinity of the current PQL of 5 |ig/L, it may not be
appropriate to recommend lowering of the PQL due to the lack of data below the current PQL.
No new or revised methods that may be expected to improve analytical performance in the
vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
62
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Di(2-ethylhexyl)phthalate (DEHP)
Results of the Methods Comparison
Exhibit 44 summarizes the MDLs for di(2-ethylhexyl)phthalate as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of DEHP in drinking water samples during the years 2000-2007.
Exhibit 44: Analytical Methods for Di(2-ethylhexyl)phthalate
MCL = 0.006 mg/L Current PQL = 0.006 mg/L DL = 0.0006 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
506
525.2
Technique
LLE or LSE and GC/PID
LSE and CCGC/MS
MDL ug/L
2.25
0.46-1.3
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141.24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for DEHP is 6 u,g/L. The Six-Year 1 and Six-Year 2/ERA data sets are
regressed separately (see Exhibit 45). The Six-Year 1 PE data for DEHP were regressed as part
of the March 2003 report. Two of the 18 spike values in the Six-Year 1 data set are below the
current PQL of 6 u.g/L. None of the Six-Year 2/ERA data are below the current PQL. Four
concentrations from the Six-Year 1 data set (two below the current PQL and two in the vicinity
of the current PQL) have passing rates of less than or equal to 75%. Three of the Six-Year
2/ERA passing rates are less than or equal to 75%.
63
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 45: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Di(2-
ethylhexyl)phthalate
O)
_c
'in
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Ethylene dibromide (EDB)
Results of the Methods Comparison
Exhibit 46 summarizes the MDLs for ethylene dibromide as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of EDB in drinking water samples during the years 2000-2007.
Exhibit 46: Analytical Methods for Ethylene Dibromide
MCL = 0.00005 mg/L Current PQL = 0.00005 mg/L DL = 0.00001 mg/L
Acceptance Criteria = + 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
504.1
551.1
Technique
ME and GC
LLE/GC w/ ECD
MDL ug/L
0.01
0.007 -
0.032
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141 .24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for EDB is 0.05 ug/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 47). The Six-Year 1 PE data for EDB were evaluated but
not regressed in the March 2003 report. None of the Six-Year 1 or the Six-Year 2/ERA PT data
for EDB are below the current PQL of 0.05 |ig/L. Nearly all of the passing rates in the Six-Year
1 and Six-Year 2/ERA data set are above 75% (with the exception of three passing rates equal to
75%).
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Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 47: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Ethylene Dibromide
100
g
ro
Q_
I
2
ro
fc
90 -
70 -
60 H
50 -
30 H
20 -
10 -
0.0
.
75%
Acceptance Criteria
= + 40%
Current PQL
= 0.05 ug/L
0.5
1.0 1.5
True Value (ug/L)
2.0
2.5
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Ethylene Dibromide
Although most passing rate of laboratories for both Six-Year 2/ERA and Six-Year 1 data
sets are high (> 75%), it may not be appropriate to recommend lowering of the PQL due to the
lack of data below or in the vicinity of the current PQL of 0.05 |ig/L. The variability in the
passing rates for both data sets further supports this recommendation. No new or revised
methods that may be expected to improve analytical performance in the vicinity of the current
PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-2007.
66
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Pentachlorophenol
Results of the Methods Comparison
Exhibit 48 summarizes the MDLs for pentachlorophenol as documented in EPA-
developed analytical methods. Updates to one method (ASTM D5317-98) have been approved
for the analysis of pentachlorophenol in drinking water samples during the years 2000-2007 (see
Exhibit A-l). These updates are minor technical revisions that are not anticipated to improve
analytical performance near the PQL. In addition, a new method, EPA Method 515.4, was
approved (Federal Register, Vol. 67, No. 209, p. 65888, October 29, 2002; see Exhibit A-l).
The low end of the MDL range for pentachlorophenol by EPA Method 515.4 is lower than that
obtained from other approved methods, which suggests that laboratory performance at low
concentrations may be improved through use of Method 515.4.
Exhibit 48: Analytical Methods for Pentachlorophenol
MCL = 0.001 mg/L Current PQL = 0.001 mg/L DL = 0.00004 mg/L
Acceptance Criteria = + 50%
EPA Methods Approved for the Analysis of Drinking Water
Method
515.1
515.2
515.3
515.4
525.2
555
Technique
GC/ECD
LSE and GC/ECD
LLED and GC/ELCD
LLMED and GC/ECD
LSE and CCGC/MS
HPLC/PDAUVD
MDL ug/L
0.032
0.16
0.021 -
0.085
0.014-
0.084
0.72-1.0
0.15-1.6
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141 .24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for pentachlorophenol is 1 |ig/L. The Six-Year 1 and Six-Year 2/ERA
data sets are regressed separately (see Exhibit 49). The Six-Year 1 PE data for
pentachlorophenol were regressed as part of the March 2003 report. Only one of the 16 spike
values in the Six-Year 1 data set is below the current PQL of 1 |ig/L. None of the Six-Year
2/ERA data are below the current PQL. Passing rates for both data sets are highly variable.
67
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Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 49: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Pentachlorophenol
in
ra
a.
in
at
Ģ
2
o
ra
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 50%
Current PQL
= 1 ug/L
10 20 30 40 50 60 70 80
True Value (ug/L)
90 100
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Pentachlorophenol
Given the limited data below the PQL of 1 |ig/L (only one Six-Year 1 datum just below
the PQL) and the high variability in the passing rates in the vicinity of the PQL for both the Six-
Year 1 and the Six-Year 2/ERA data sets, it may not be appropriate to recommend lowering of
the PQL. However, the approval of EPA Method 515.4 for the analysis of pentachlorophenol
provides a lower MDL than was achievable by use of other approved methods. This may lead to
an overall improvement in analytical performance in the vicinity of the current PQL and could
suggest possible reduction of the PQL.
68
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Polychlorinatedbiphenyls (PCBs) as Decachlorobiphenyl (DCBP)
Results of the Methods Comparison
Exhibits 50 and 51 summarize the MDLs for polychlorinatedbiphenyls as documented in
EPA-developed analytical methods. Note that the PE/PT data and the MCL for PCBs are based
on PCBs as decachlorobiphenyl. Performing this analysis involves a perchlorination step that
converts mono- to octa-chlorinated biphenyl to the completely chlorinated perchlorobiphenyl or
decachlorobiphenyl (see EPA Method 508A below). However, PCBs may also be quantitated as
carbon:chlorine mass ratio groups known as aroclors. EPA Method 508A must be used for
compliance if aroclor screening (e.g., qualitative identification) indicates the presence of PCBs.
Available MDLs for both groups are given in Exhibits 50 and 51. No updated or new analytical
methods have been approved for the analysis of PCBs in drinking water samples during the years
2000-2007.
Exhibit 50: Analytical Methods for PCBs: As Decachlorobiphenyl
MCL = 0.0005 mg/L Current PQL = 0.0005 mg/L DL = 0.0001 mg/L
Acceptance Criteria = + 1 00%
EPA Methods Approved for the Analysis of Drinking Water
Method
508A
Technique
Perchlorination/GC (2-Chlorobiphenyl as source)
MDL ug/L
0.08
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Exhibit 51: Analytical Methods for PCBs: As Aroclors
MCL = 0.0005 mg/L Current PQL = 0.0005 mg/L DL = 0.00008-0.02 mg/L
Acceptance Criteria = + 1 00%
EPA Methods Approved for the Analysis of Drinking Water
Method
505
508
508.1
525.2
Technique
ME and GC
GC/ECD
LSE and ECGC
LSE and CCGC/MS
MDL ug/L
0.08-15.0
No MDLs
0.012-
0.044
0.018-0.56
Notes: Regulatory DLs for PCBs as Aroclors are listed at 40 CFR 141 .24(h)(13)(2).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Note that use of these methods is only permitted for screening of drinking water samples.
Demonstration of compliance with the MCL if Aroclors are detected must be performed in
accordance with EPA Method 508A (see Exhibit 50).
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Results of the POL Analysis
The current PQL for PCBs is 0.5 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets are
regressed separately (see Exhibit 52). The Six-Year 1 PE data for PCBs were evaluated but were
not regressed as part of the March 2003 report. Only one of the 11 spike values in the Six-Year
1 data set is below the current PQL of 0.5 |ig/L. None of the Six-Year 2/ERA data are below the
current PQL. Passing rates in the vicinity of the current PQL are highly variable.
in
ra
a.
tn
at
2
o
ra
Exhibit 52: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - PCBs
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 100%
Current PQL
= 0.5ug/L
0.0 0.5 1.0 1.5 2.0 2.5 3.0
True Value (ug/L)
3.5
4.0
4.5
5.0
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Polychlorinatedbiphenvls
Although the Six-Year 2/ERA laboratory passing rates are high (well above 75%), given
the low laboratory passing rates and decreasing trend in laboratory passing rates below and in the
vicinity of the PQL of 0.5 |ig/L for the Six-Year 1 data set and the lack of data below the PQL
for the Six-Year 2/ERA data set, it may not be appropriate to recommend lowering of the PQL.
No new or revised methods that may be expected to improve analytical performance in the
vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Thallium
Results of the Methods Comparison
Exhibit 53 summarizes the MDLs for thallium as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of thallium in drinking water samples during the years 2000-2007.
Exhibit 53: Analytical Methods for Thallium
MCL = 0.002 mg/L Current PQL = 0.002 mg/L DL = 0.0003-0.001 mg/L
Acceptance Criteria = + 30%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.8
200.9
Technique
ICP/MS
GFAA
MDL mg/L
0.00001 -
0.0003
0.0007
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the POL Analysis
The current PQL for thallium is 0.002 mg/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 54). The Six-Year 1 PE data for thallium were
evaluated but were not regressed in the March 2003 report. Only one of the 19 spike values in
the Six-Year 1 data set is less than the current PQL of 0.002 mg/L. None of the Six-Year 2/ERA
data are below the current PQL. Nearly all of the passing rates in both data sets are above 75%
(with the exception of two passing rates in the Six-Year 2/ERA data that are equal to 75%). In
addition, both regression lines are well above 75%.
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 54: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Thallium
100
in
ra
a.
in
at
S
2
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 30%
Current PQL
= 0.002 mg/L
0.00 0.01 0.01 0.02 0.02 0.03
True Value (mg/L)
0.03
0.04
0.04
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Thallium
Although the Six-Year 1 laboratory passing rates are high (above 75%) below and in the
vicinity of the PQL of 0.002 mg/L, given the lack of data below the PQL and the lower
laboratory passing rates in the vicinity of the PQL for the Six-Year 2/ERA data set, it may not be
appropriate to recommend lowering of the PQL. No new or revised methods that may be
expected to improve analytical performance in the vicinity of the current PQL (and hence
suggest possible reduction of the PQL) have been approved from 2000-2007.
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October 2009
6.2 Analytes with Maximum Contaminant Level (MCL) Greater Than the Current
PQL and Thus it is Technically Feasible to Reduce an MCL
The analytes in this category have an existing PQL that is less than the MCL. If new
health information were to become available for any of these analytes, causing EPA to consider
reducing the MCL, the existing PQL would not hinder reduction of the MCL (to the level of the
current PQL). Forty-one analytes fit into this category. These 41 analytes can be further
categorized into the three groups mentioned in Section 6.0 depending on whether or not the
PE/PT assessments support the further reduction of the current PQL.
6.2.1 PQL Assessment Supports Reduction of the Current PQL
Of the 41 analytes mentioned above, 11 analytes have an existing PQL that is less than
the MCL and their PE/PT data suggest that the PQL could be lower.
Barium
Results of the Methods Comparison
Exhibit 55 summarizes the MDLs for barium as documented in EPA-developed analytical
methods. Updates to three methods have been approved for the analysis of barium in drinking
water samples during the years 2000-2007 (see Exhibit A-l). These updates are associated with
administrative and technical changes or clarifications that are not expected to improve analytical
performance near the PQL. The updated methods are proprietary and are not listed in Exhibit 55.
Exhibit 55: Analytical Methods for Barium
MCL = 2 mg/L Current PQL =0.15 mg/L DL = 0.002-0.1 mg/L
Acceptance Criteria = + 1 5%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.7
200.8
Technique
ICP-AES
ICP/MS
MDL mg/L
0.001
0.00004 -
0.0008
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the POL Analysis
The current PQL for barium is 0.15 mg/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 56). The Six-Year 1 PE data for barium were not evaluated
in the March 2003 report. Two of the 19 spike values in the Six-Year 1 data set are below the
current PQL of 0.15 mg/L. No Six-Year 2/ERA data are below the current PQL. With the
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
exception of one spike value in the Six-Year 1 data, all of the passing rates exceed 75%. Both
the Six-Year 1 and ERA regression lines are well above 75%.
Exhibit 56: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Barium
100
90 -
80 -
70 -
ro
Q.
I 50
Ģ
ro
o
&
ra
40 -
30 -
20 -
10 -
0.00
75%
Acceptance Criteria
= + 15%
Current PQL
= 0.15 mg/L
0.40
0.80 1.20 1.60
True Value (mg/L)
2.00
2.40
2.80
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Barium
The high laboratory passing rates (well above 75%) at just below and in the vicinity of
the current PQL of 15 mg/L for the Six-Year 1 data set suggest that the PQL could be lower;
however any reduction might be small due to the lower passing rate at the lowest spike
concentration. Although there are no Six-Year 2/ERA data below the PQL, laboratory passing
rates in the vicinity of the PQL are also high, which may support the Six-Year 1 data conclusion
that the PQL could be lower. No new or revised methods that may be expected to improve
analytical performance in the vicinity of the current PQL (and hence suggest possible reduction
of the PQL) have been approved from 2000-2007.
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
1,4-Dichlorobenzene
Results of the Methods Comparison
Exhibit 57 summarizes the MDLs for 1,4-dichlorobenzene as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of 1,4-dichlorobenzene in drinking water samples during the years 2000-2007.
Exhibit 57: Analytical Methods for 1,4-Dichlorobenzene
MCL = 0.075 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01 -0.04
0.03-0.04
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for 1,4-dichlorobenzene is 5 |ig/L. The Six-Year 1 and Six-Year
2/ERA data sets are regressed separately (see Exhibit 58). The Six-Year 1 PE data for 1,4-
dichlorobenzene were evaluated but were not regressed as part of the March 2003 report. Note
that the acceptance criteria are + 40% at spike concentrations below 10 |ig/L and + 20% at or
above 10 u.g/L; hence the data are regressed as two independent populations. One of the 17
spike values from the Six-Year 1 data is below the current PQL of 5 |ig/L. Nine of the 60 Six-
Year 2/ERA spike values are at or below the current PQL. All of the passing rates for the Six-
Year 1 and Six-Year 2/ERA data are well above 75%.
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EPA815-B-09-003
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Exhibit 58
100
Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,4-Dichlorobenzene
90 -
80 -
70 -
O)
1 6°-
ro
a.
8 50 1
S
40 -
30 -
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
II.
75%
Acceptance Criteria
= + 20%
3 10 12
True Value (ug/L)
14
16
18
20
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data Ator Above 10 ug/L
Six-Year 1 Data Ator Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for 1,4-Dichlorobenzene
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 ug/L for both the Six-Year 1 and Six-Year 2/ERA data sets suggest that the PQL could
be lower. Although there is only one Six-Year 1 datum below the PQL, laboratory passing rates
below and in the vicinity of the PQL are well above 75%, which supports the Six-Year 2/ERA
data conclusion that the PQL could be lower. No new or revised methods that may be expected
to improve analytical performance in the vicinity of the current PQL (and hence suggest possible
reduction of the PQL) have been approved from 2000-2007.
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
cis-1,2-Dichloroethylene
Results of the Methods Comparison
Exhibit 59 summarizes the MDLs for c/5-l,2-dichloroethylene as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of c/5-l,2-dichloroethylene in drinking water samples during the years 2000-2007.
Exhibit 59: Analytical Methods for cis-l,2-Dichloroethylene
MCL = 0.07 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01 -0.05
0.06-0.12
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for c/5-l,2-dichloroethylene is 5 |ig/L. The Six-Year 1 and Six-Year
2/ERA data sets are regressed separately (see Exhibit 60). The Six-Year 1 PE data for cis-1,2-
dichloroethylene were not evaluated as part of the March 2003 report. Note that the acceptance
criteria are + 40% at spike concentrations below 10 |ig/L and + 20% at or above 10 |ig/L; hence
the data are regressed as two independent populations. No Six-Year 1 data are available below
the current PQL of 5 u.g/L. Five of the 60 spike values in the Six-Year 2/ERA data are below the
current PQL. All of the passing rates are above 75% (with the exception of one passing rate
equal to 75%).
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Exhibit 60: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - cis-1,2-
Dichloroethylene
in
01
2
o
Ģ1
ra
100
90 -
70 -
O)
c
8 60
ro
50 -
40 -
30 -
20 -
10 -
Acceptance Criteria
= + 40%
75%
Acceptance Criteria
= + 20%
Current PQL
= 5 ug/L
10 15 20 25 30
True Value (ug/L)
35
40
45
50
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data Ator Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for c/s-l,2-Dichloroethylene
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 ug/L for the Six-Year 2/ERA data set suggest that the PQL could be lower. Although
there are no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL
are also high, which may support the Six-Year 2/ERA data conclusion that the PQL could be
lower. No new or revised methods that may be expected to improve analytical performance in
the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
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1,1-Dichloroethylene
Results of the Methods Comparison
Exhibit 61 summarizes the MDLs for 1,1-dichloroethylene as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of 1,1-dichloroethylene in drinking water samples during the years 2000-2007.
Exhibit 61: Analytical Methods for 1,1-Dichloroethylene
MCL = 0.007 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.04-0.1
0.05-0.12
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the POL Analysis
The current PQL for 1,1-dichloroethylene is 5 |ig/L. The Six-Year 1 and Six-Year
2/ERA data sets are regressed separately (see Exhibit 62). The Six-Year 1 PE data for 1,1-
dichloroethylene were evaluated but were not regressed as part of the March 2003 report. Note
that the acceptance criteria are + 40% at spike concentrations below 10 jig/L and + 20% at or
above 10 |ig/L; hence the data are regressed as two independent populations. No Six-Year 1 data
are available below the current PQL of 5 |ig/L. Ten of the 60 spike values in the Six-Year
2/ERA data are below the current PQL. While three of the four regression lines are above the
75% passing rate threshold, a few passing rates (all above the current PQL) are below 75%. One
of the Six-Year 1 spike values (equal to 11.7 |ig/L) has a passing rate of just under 20%. This
causes the Six-Year 1 regression line to cross below the 75% threshold. This potential outlier
represents 56 laboratories, of which 45 failed. It is possible (but uncertain) that this low passing
rate is not due to poor laboratory performance but rather to an erroneous PE sample or other
aberration, since low "national" passing rates around 20% are very uncommon. The more recent
Six-Year 2/ERA data support generally high laboratory performance.
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Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
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Exhibit 62: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,1-Dichloroethylene
O)
c
3
.a
3
70 -
ro
a.
I 50
40 -
30 -
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
75%
Acceptance Criteria
= + 20%
6 8 10 12
True Value (ug/L)
16
18
20
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data Ator Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for 1,1-Dichloroethylene
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 |ig/L for the Six-Year 2/ERA data set suggest that the PQL could be lower. Although
there are no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL
are also high, which may support the Six-Year 2/ERA data conclusion that the PQL could be
lower. No new or revised methods that may be expected to improve analytical performance in
the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
Ethylbenzene
Results of the Methods Comparison
Exhibit 63 summarizes the MDLs for ethylbenzene as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of ethylbenzene in drinking water samples during the years 2000-2007.
Exhibit 63: Analytical Methods for Ethylbenzene
MCL = 0.7 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01 -0.04
0.03-0.06
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for ethylbenzene is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 64). The Six-Year 1 PE data for ethylbenzene were not
evaluated as part of the March 2003 report. Note that the acceptance criteria are + 40% at spike
concentrations below 10 |ig/L and + 20% at or above 10 |ig/L; hence the data are regressed as
two independent populations. No Six-Year 1 data are available below the current PQL of 5
u.g/L. Eighteen of the 60 spike values in the Six-Year 2/ERA data are below the current PQL.
All of the passing rates are above 75% (with the exception of one passing rate equal to 75%).
81
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 64: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Ethylbenzene
in
ra
0.
in
at
90 -
80 -
70
60
50
40
30
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
75%
Acceptance Criteria
= + 20%
3 10 12
True Value (ug/L)
14
16
18
20
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data At or Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for Ethylbenzene
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 ug/L for the Six-Year 2/ERA data set suggest that the PQL could be lower. Although
there are no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL
are also high, which may support the Six-Year 2/ERA data conclusion that the PQL could be
lower. No new or revised methods that may be expected to improve analytical performance in
the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
82
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
Monochlorobenzene (Chlorobenzene)
Results of the Methods Comparison
Exhibit 65 summarizes the MDLs for monochlorobenzene as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of monochlorobenzene in drinking water samples during the years 2000-2007.
Exhibit 65: Analytical Methods for Monochlorobenzene
MCL = 0.1 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01 -0.02
0.03-0.04
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the POL Analysis
The current PQL for monochlorobenzene is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA
data sets are regressed separately (see Exhibit 66). The Six-Year 1 PE data for
monochlorobenzene were not evaluated as part of the March 2003 report. Note that the
acceptance criteria are + 40% at spike concentrations below 10 jig/L and + 20% at or above 10
|ig/L; hence the data are regressed as two independent populations. No Six-Year 1 data are
available below the current PQL of 5 |ig/L. Three of the 60 spike values in the Six-Year 2/ERA
data set are below the current PQL. All of the passing rates are above 75%, and all four
regression lines are well above 75%.
83
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 66: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Monochlorobenzene
100
in
in
ra
0.
in
at
90 -
80 -
70 -
60 -
50 -
O 40 H
ro
^ 30 H
20 -
10 -
0
VK
Acceptance Criteria
= + 40%
75%
Acceptance Criteria
= + 20%
Current PQL
= 5 ug/L
0
10 15 20 25 30
True Value (ug/L)
35
40
45
50
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data At or Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for Monochlorobenzene
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 ug/L for the Six-Year 2/ERA data set suggest that the PQL could be lower. Although
there are no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL
are also high, which may support the Six-Year 2/ERA data conclusion that the PQL could be
lower. No new or revised methods that may be expected to improve analytical performance in
the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Nitrite (as N)
Results of the Methods Comparison
Exhibit 67 summarizes the MDLs for nitrite as documented in EPA-developed analytical
methods. Updates to eleven methods and two new methods (EPA Method 300.1 and ASTM
D6508, rev. 2) have been approved for the analysis of nitrite in drinking water samples during
the years 2000-2007 (Federal Register, Vol. 67, No. 205, p. 65220, October 23, 2002; Federal
Register, Vol. 72, No. 47, p. 11200, March 12, 2007; see Exhibit A-l). The updates to methods
are associated with administrative and technical changes or clarifications that are not expected to
improve analytical performance near the PQL. The MDL for EPA Method 300.1 is lower than
that for EPA Method 300.0 which suggests that laboratory performance at low concentrations
may be improved through use of Method 300.1. Since the new ASTM method is proprietary, it
is uncertain whether new MDLs may be lower than those for other methods; in addition, the
updated methods are proprietary and are not listed in Exhibit 67.
Exhibit 67: Analytical Methods for Nitrite (as N)
MCL=1mg/L Current PQL = 0.4 mg/L DL = 0.004-0.103 mg/L
Acceptance Criteria = + 1 5%
EPA Methods Approved for the Analysis of Drinking Water
Method
300.0
300.1
353.2
Technique
1C
1C
Auto Colorimetry
MDL mg/L
0.004
0.001
No MDL
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the POL Analysis
The current PQL for nitrite is 0.4 mg/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 68). The Six-Year 1 PE data for nitrite were not evaluated
in the March 2003 report. Five of the 20 spike values in the Six-Year 1 data set are less than the
current PQL of 0.4 mg/L. No Six-Year 2/ERA data are below the current PQL. All of the
passing rates are above 75% and both regression lines are also well above 75%.
85
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 68: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Nitrite
100
n
in
ra
a.
in
o
2
o
&
ra
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0.0
75%
Acceptance Criteria
= + 15%
Current PQL
= 0.4mg/L
0.5
1.0 1.5
True Value (mg/L)
2.0
2.5
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Nitrite
The high laboratory passing rates (above 75%) at concentrations below the current PQL
of 5 |ig/L for the Six-Year 1 data set suggest that the PQL could be lower. Although there are no
Six-Year 2/ERA data below the PQL, laboratory passing rates in the vicinity of the PQL are also
high, which may support the Six-Year 1 data conclusion that the PQL could be lower. In
addition, the approval of EPA Method 300.1 for the analysis of nitrite provides a lower MDL
than was achievable by use of EPA Method 300.0. This may lead to an overall improvement in
analytical performance in the vicinity of the current PQL and could suggest possible reduction of
the PQL.
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
Styrene
Results of the Methods Comparison
Exhibit 69 summarizes the MDLs for styrene as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of styrene in drinking water samples during the years 2000-2007.
Exhibit 69: Analytical Methods for Styrene
MCL = 0.1 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01 -0.1
0.04-0.06
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for styrene is 5 u.g/L. The Six-Year 1 and Six-Year 2/ERA data sets are
regressed separately (see Exhibit 70). The Six-Year 1 PE data for styrene were not evaluated as
part of the March 2003 report. Note that the acceptance criteria are + 40% at spike
concentrations below 10 |ig/L and + 20% at or above 10 |ig/L; hence the data are regressed as
two independent populations. No Six-Year 1 data are available below the current PQL of 5
u.g/L. Six of the 60 spike values in the Six-Year 2/ERA data are below the current PQL. All of
the passing rates are above 75% (with the exception of one passing rate equal to 75%).
Furthermore, the regression lines are well above 75%.
87
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 70: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Styrene
100
O)
90
80
70
60
50
ra
5 40
30
20
10
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
75%
Acceptance Criteria
= + 20%
8 10 12
True Value (ug/L)
14
16
18
20
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
75% Passing Rate
ERAData AtorAbove 10 ug/L
Six-Year 1 Data AtorAbove 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for Styrene
The high laboratory passing rates (75% or above) at concentrations below the current
PQL of 5 ug/L for the Six-Year 2/ERA data set suggest that the PQL could be lower. Although
there are no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL
are also high, which may support the Six-Year 1 data conclusion that the PQL could be lower.
No new or revised methods that may be expected to improve analytical performance in the
vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
Toluene
Results of the Methods Comparison
Exhibit 71 summarizes the MDLs for toluene as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of toluene in drinking water samples during the years 2000-2007.
Exhibit 71: Analytical Methods for Toluene
MCL = 1 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01 -0.02
0.08-0.11
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for toluene is 5 u.g/L. The Six-Year 1 and Six-Year 2/ERA data sets are
regressed separately (see Exhibit 72). The Six-Year 1 PE data for toluene were evaluated but
were not regressed as part of the March 2003 report. Note that the acceptance criteria are + 40%
at spike concentrations below 10 |ig/L and + 20% at or above 10 |ig/L; hence the data are
regressed as two independent populations. No Six-Year 1 data are available below the current
PQL of 5 u.g/L. Nine of the 60 spike values in the Six-Year 2/ERA data are below the current
PQL. All of the passing rates and all four regression lines are above 75%.
89
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 72: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Toluene
O)
_c
'in
V)
ra
a.
V)
.0)
&
5
o
.a
100
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
75%
Acceptance Criteria
= + 20%
10 15
True Value (ug/L)
20
25
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data At or Above 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for Toluene
The high laboratory passing rates (well above 75%) at concentrations below the current
PQL of 5 ug/L for the Six-Year 2/ERA data set suggest that the PQL could be lower. Although
there are no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL
are also high, which may support the Six-Year 2/ERA data conclusion that the PQL could be
lower. No new or revised methods that may be expected to improve analytical performance in
the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been
approved from 2000-2007.
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
1,2,4- Trichlorobenzene
Results of the Methods Comparison
Exhibit 73 summarizes the MDLs for 1,2,4-trichlorobenzene as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of 1,2,4-trichlorobenzene in drinking water samples during the years 2000-2007.
Exhibit 73: Analytical Methods for 1,2,4-Trichlorobenzene
MCL = 0.07 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.02-0.08
0.04-0.20
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for 1,2,4-trichlorobenzene is 5 |ig/L. The Six-Year 1 and Six-Year
2/ERA data sets are regressed separately (see Exhibit 74). The Six-Year 1 PE data for 1,2,4-
trichlorobenzene were not evaluated as part of the March 2003 report. Note that the acceptance
criteria are + 40% at spike concentrations below 10 |ig/L and + 20% at or above 10 |ig/L; hence
the data are regressed as two independent populations. No Six-Year 1 data are available below
the current PQL 5 u.g/L. Six of the 60 spike values in the Six-Year 2/ERA data are below the
current PQL. All but four of the Six-Year 2/ERA passing rates are above 75%. Furthermore, the
four regression lines are well above 75%.
91
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 74: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,2,4-
Trichlorobenzene
n
in
ra
a.
in
o
.a
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
'^ą*.
*
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
. *
_S__.j_ŧ ^-*-
V -^*^
75%
Acceptance Criteria
= + 20%
10 15
True Value (ug/L)
20
25
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data Ator Above 10 ug/L
Six-Year 1 Data Ator Above 10 ug/L
PQL
-10 ug/L Acceptance Criteria Boundary
Conclusion for 1,2,4-Trichlorobenzene
The high laboratory passing rates (>80%) at concentrations below the current PQL of 5
Hg/L for the Six-Year 2/ERA data set suggest that the PQL could be lower. Although there are
no Six-Year 1 data below the PQL, laboratory passing rates in the vicinity of the PQL are also
high, which may support the Six-Year 2/ERA data conclusion that the PQL could be lower. No
new or revised methods that may be expected to improve analytical performance in the vicinity
of the current PQL (and hence suggest possible reduction of the PQL) have been approved from
2000-2007.
92
-------
EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
1,1,1-Trichloroethane
Results of the Methods Comparison
Exhibit 75 summarizes the MDLs for 1,1,1-trichloroethane as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of 1,1,1-trichloroethane in drinking water samples during the years 2000-2007.
Exhibit 75: Analytical Methods for l,l?l-Trichloroethane
MCL = 0.07 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
551.1
Technique
CCGCwithPID/ELCD
CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.01 -0.03
0.04-0.08
0.005 -
0.012
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the POL Analysis
The current PQL for 1,1,1-trichloroethane is 5 |ig/L. The Six-Year 1 and Six-Year
2/ERA data sets are regressed separately (see Exhibit 76). The Six-Year 1 PE data for 1,1,1-
trichloroethane were evaluated but were not regressed as part of the March 2003 report. Note
that the acceptance criteria are + 40% at spike concentrations below 10 |ig/L and + 20% at or
above 10 |ig/L; hence the data are regressed as two independent populations. One of the 17
spike values from the Six-Year 1 data is below the current PQL of 5 |ig/L. Ten of the 60 Six-
Year 2/ERA spike values are below the current PQL. All of the passing rates for the Six-Year 1
and Six-Year 2/ERA data are above 75%.
93
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 76: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,1,1-Trichloroethane
100
s?
70-
O)
8 60
ra
a.
I 50
90%) at concentrations below the current
PQL of 5 ug/L for both the Six-Year 1 and Six-Year 2/ERA data sets suggest that the PQL could
be lower. Although there is only one Six-Year 1 datum below the PQL, laboratory passing rates
below and in the vicinity of the PQL are well above 75%, which supports the conclusion that the
PQL could be lower. No new or revised methods that may be expected to improve analytical
performance in the vicinity of the current PQL (and hence suggest possible reduction of the
PQL) have been approved from 2000-2007.
94
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
6.2.2 PQL Assessment May Support Reduction of the Current PQL
Of the 41 analytes mentioned in Section 6.2, six analytes have an existing PQL that is
less than the MCL and their PE/PT data suggest that the PQL could possibly be lower.
Atrazine
Results of the Methods Comparison
Exhibit 77 summarizes the MDLs for atrazine as documented in EPA-developed
analytical methods. No updated methods have been approved for the analysis of atrazine in
drinking water samples during the years 2000-2007; however, a new method, Syngenta AG-625,
was approved (Federal Register, Vol. 67, No. 209, p. 65888, October 29, 2002; see Exhibit A-l).
Since the method is proprietary, the MDL/DL for atrazine by Syngenta AG-625 is not known,
but the Federal Register notice indicates that this method "meets EPA's criteria for method
performance." Thus, it is uncertain whether new MDLs may be lower than those for other
methods.
Exhibit 77: Analytical Methods for Atrazine
MCL = 0.003 mg/L Current PQL = 0.001 mg/L DL = 0.0001 mg/L
Acceptance Criteria = + 45%
EPA Methods Approved for the Analysis of Drinking Water
Method
505
507
508.1
525.2
551.1
Technique
ME and GC
GC/N-PD
LSE and ECGC
LSE and CCGC/MS
LLE/GC w/ ECD
MDL ug/L
2.4
0.015
0.003
0.065 -
0.081
0.082 -
0.121
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141 .24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for atrazine is 1 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 78). The Six-Year 1 PE data for atrazine were not
evaluated in the March 2003 report. Three of the 20 spike values in the Six-Year 1 data are
below the current PQL of 1 |ig/L. No Six-Year 2/ERA data are below the current PQL. With
the exception of one spike value, all of the Six-Year 1 passing rates exceed 75%, while the Six-
Year 2/ERA passing rates are more variable. Both regression lines are well above 75%.
95
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 78: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Atrazine
n
in
ra
a.
in
o
2
2
o
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 45%
Current PQL
= 1 ug/L
10
15
20
25
30
True Value (ug/L)
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Atrazine
Given the limited data below the current PQL of 1 |ig/L but generally high laboratory
passing rates (mostly above 75%) below and in the vicinity of the PQL for the Six-Year 1 data
set, a reduction of the PQL may be considered. The Six-Year 2/ERA data exhibit some
variability, but laboratory passing rates in the vicinity of the PQL are generally >75% and may
also support PQL reduction. While a new method, Syngenta AG-625, was approved for the
analysis of atrazine in 2002, the method is proprietary and it is not known whether the DLs
and/or MDLs from this method could lead to an overall improvement in analytical performance
in the vicinity of the current PQL and suggest possible reduction of the PQL.
96
-------
EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Carbofuran
Results of the Methods Comparison
Exhibit 79 summarizes the MDLs for carbofuran as documented in EPA-developed
analytical methods. No updated methods have been approved for the analysis of carbofuran in
drinking water samples during the years 2000-2007; however, a new method, EPA Method
531.2, was approved (Federal Register, Vol. 67, No. 209, p. 65888, October 29, 2002; see
Exhibit A-l). The range of DLs/MDLs for carbofuran by EPA Method 531.2 is approximately
one order of magnitude less than the MDL from EPA Method 531.1, which suggests that
laboratory performance at low concentrations may be improved through use of Method 531.2.
Exhibit 79: Analytical Methods for Carbofuran
MCL = 0.04 mg/L Current PQL = 0.007 mg/L DL = 0.0009 mg/L
Acceptance Criteria = + 45%
EPA Methods Approved for the Analysis of Drinking Water
Method
531.1
531.2
Technique
DAI/HP LC w/ Der.
DAI/HP LC w/ Der.
MDL ug/L
0.52
0.043 -
0.058 (DL)
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141.24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for carbofuran is 7 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 80). The Six-Year 1 PE data for carbofuran were evaluated
in the March 2003 report; however, these data were not regressed in that report. Two of the 20
spike values in the Six-Year 1 data are below the current PQL of 7 |ig/L. No Six-Year 2/ERA
data are below the current PQL. The Six-Year 1 passing rates were all well above 75%; however
the passing rates for the Six-Year 2/ERA data are more variable.
97
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 80: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Carbofuran
n
in
ra
a.
in
o
2
o
&
ra
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 45%
Current PQL
= 7 ug/L
30
90
120
150
True Value (ug/L)
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Carbofuran
Given the limited data below the current PQL of 7 |ig/L but generally high laboratory
passing rates (above 75%) below and in the vicinity of the PQL for the Six-Year 1 data set, a
reduction of the PQL may be considered. The Six-Year 2/ERA data exhibit some variability,
with laboratory passing rates in the vicinity of the PQL ranging from less than 70% to 100%
which may not support the Six-Year 1 data conclusion that the PQL could be lower. The range
of DLs/MDLs for carbofuran by recently-approved EPA Method 531.2 is approximately one
order of magnitude lower than the MDL from EPA Method 531.1. This may lead to an overall
improvement in analytical performance in the vicinity of the current PQL and could suggest
possible reduction of the PQL.
98
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
trans-l,2-Dichloroethylene
Results of the Methods Comparison
Exhibit 81 summarizes the MDLs for frvms-l^-dichloroethylene as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of fr'am'-l,2-dichloroethylene in drinking water samples during the years 2000-2007.
Exhibit 81: Analytical Methods for fraŦs-l,2-Dichloroethylene
MCL = 0.1 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.03-0.06
0.03-0.06
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the POL Analysis
The current PQL for fraw5-l,2-dichloroethylene is 5 |ig/L. The Six-Year 1 and Six-Year
2/ERA data sets are regressed separately (see Exhibit 82). The Six-Year 1 PE data for trans-1,2-
dichloroethylene were not evaluated as part of the March 2003 report. Note that the acceptance
criteria are + 40% at spike concentrations below 10 jig/L and + 20% at or above 10 |ig/L; hence
the data are regressed as two independent populations. No Six-Year 1 data are available below
the current PQL of 5 |ig/L. Three of the 60 spike values in the Six-Year 2/ERA data set are
below the current PQL. All but two of the passing rates are above 75%.
99
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 82: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - tmns-1,2-
Dichloroethylene
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(fl
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D.
(fl
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3
100
90
80
70 -
60
50
40
30
20
10 -
Acceptance Criteria
= + 40%
75%
Acceptance Criteria
= + 20%
Current PQL
= 5 ug/L
10 15 20 25 30
True Value (ug/L)
35
40
45
50
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L PQL
Six-Year! Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary
Conclusion for frvmy-Q-Dichloroethylene
Given the limited data below the current PQL of 5 |ig/L but generally high laboratory
passing rates (well above 75%) below and in the vicinity of the PQL for the Six-Year 2/ERA
data set and in the vicinity of the PQL for the Six-Year 1 data set, a reduction of the PQL may be
considered. The Six-Year 2/ERA data exhibit some variability, with laboratory passing rates in
the vicinity of the PQL ranging from slightly below 75% to 100%; which may support the Six-
Year 1 data conclusion that the PQL could be lower. No new or revised methods that may be
expected to improve analytical performance in the vicinity of the current PQL (and hence
suggest possible reduction of the PQL) have been approved from 2000-2007.
Page 100
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Hexachlorocyclopentadiene
Results of the Methods Comparison
Exhibit 83 summarizes the MDLs for hexachlorocyclopentadiene as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of hexachlorocyclopentadiene in drinking water samples during the years 2000-
2007.
Exhibit 83: Analytical Methods for Hexachlorocyclopentadiene
MCL = 0.05 mg/L Current PQL = 0.001 mg/L DL =
Acceptance Criteria = Mean + 2 Std Dev
0.0001 mg/L
EPA Methods Approved for the Analysis of Drinking Water
Method
505
508
508.1
525.2
551.1
Technique
ME and GC
GC/ECD
LSE and ECGC
LSE and CCGC/MS
LLE/GC w/ ECD
Notes: Regulatory DLs for synthetic organic compounds are listed at
Acceptance Criteria for synthetic organic compounds are listed at 40
MDL ug/L
0.13
No MDL
0.004
0.072-0.16
0.016-
0.018
40CFR141.24(h)(18).
CFR141.24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for hexachlorocyclopentadiene is 1 |ig/L. The Six-Year 1 and Six-Year
2/ERA data sets are regressed separately (see Exhibit 84). The Six-Year 1 PE data for
hexachlorocyclopentadiene were evaluated but were not regressed as part of the March 2003
report. Six of the 20 spike values in the Six-Year 1 data set are below the current PQL of 1 |ig/L.
No Six-Year 2/ERA data are below the current PQL. All but one of the Six-Year 1 passing rates,
along with the Six-Year 1 regression line, are above 75%; however, the Six-Year 2/ERA passing
rates are more variable, with several passing rates below 75%.
Page 101
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 84: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data
Hexachlorocyclopentadiene
100
in
ra
a.
in
01
c
S
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0
0.0
75%
Acceptance Criteria
= Mean +2 SD
Current PQL
= 1 ug/L
0.5
1.0 1.5
2.0 2.5 3.0
True Value (ug/L)
3.5
4.0 4.5
5.0
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Hexachlorocyclopentadiene
Given the generally high laboratory passing rates (all but one well above 75%) below and
in the vicinity of the current PQL of 1 |ig/L for the Six-Year 1 data set, a reduction of the PQL
may be considered. The Six-Year 2/ERA data exhibit some variability, with laboratory passing
rates in the vicinity of the PQL ranging from less than 70% to 100%, which may not support the
Six-Year 1 data conclusion that the PQL could be lower. No new or revised methods that may
be expected to improve analytical performance in the vicinity of the current PQL (and hence
suggest possible reduction of the PQL) have been approved from 2000-2007.
Page 102
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Methoxychlor
Results of the Methods Comparison
Exhibit 85 summarizes the MDLs for methoxychlor as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of methoxychlor in drinking water samples during the years 2000-2007.
Exhibit 85: Analytical Methods for Methoxychlor
MCL = 0.04 mg/L Current PQL = 0.01 mg/L DL = 0.0001 mg/L
Acceptance Criteria = + 45%
EPA Methods Approved for the Analysis
Method
505
508
508.1
525.2
551.1
of Drinking Water
Technique
ME and GC
GC/ECD
LSE and ECGC
LSE and CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.96
0.022
0.003
0.033-0.13
0.008 -
0.026
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the PQL Analysis
The current PQL for methoxychlor is 10 |ig/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 86). The Six-Year 1 PE data for methoxychlor were
evaluated but were not regressed as part of the March 2003 report. Four of the 20 spike values in
the Six-Year 1 methoxychlor PE data are below the current PQL of 10 |ig/L. All of the passing
rates are above 75%. None of the Six-Year 2/ERA values are below the current PQL and the
data exhibit more variability. The Six-Year 1 regression line is well above 75%; however, the
Six-Year 2/ERA regression line predicts a decrease in passing rates with an increase in spike
values.
Page 103
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 86: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Methoxychlor
in
ra
a.
in
at
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&
ra
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 45%
Current PQL
= 10 ug/L
10 20 30 40 50 60
True Value (ug/L)
70
80
90
100
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Methoxychlor
Given the generally high laboratory passing rates (well above 75%) below and in the
vicinity of the current PQL of 10 |ig/L for the Six-Year 1 data set, a reduction of the PQL may be
considered. The Six-Year 2/ERA data exhibit some variability, with laboratory passing rates in
the vicinity of the PQL generally above 80%; however, there is more variability at higher
concentrations and a predicted downward trend at higher concentrations. Overall, the Six-Year 2
data may not support the Six-Year 1 data conclusion that the PQL could be lower. No new or
revised methods that may be expected to improve analytical performance in the vicinity of the
current PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-
2007.
Page 104
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
2-(2,4,5-Trichlorophenoxy)propanoic acid (2,4,5-TP; Silvex)
Results of the Methods Comparison
Exhibit 87 summarizes the MDLs for 2-(2,4,5-trichlorophenoxy)propanoic acid as
documented in EPA-developed analytical methods. Updates to one method have been approved
for the analysis of 2,4,5-TP in drinking water samples during the years 2000-2007 (see Exhibit
A-l). These updates are minor technical revisions that are not anticipated to improve analytical
performance near the PQL. In addition, a new method, EPA Method 515.4 was approved
(Federal Register, Vol. 67, No. 209, p. 65888, October 29, 2002; see Exhibit A-l). The MDL for
2,4,5-TP by EPA Method 515.4 is somewhat lower than that obtained from other EPA methods,
which suggests that laboratory performance at low concentrations may be improved through use
of Method 515.4.
Exhibit 87: Analytical Methods for 2,4,5-TP (Silvex)
MCL = 0.05 mg/L Current PQL = 0.005 mg/L DL =
Acceptance Criteria = + 50%
0.0002 mg/L
EPA Methods Approved for the Analysis of Drinking Water
Method
515.1
515.2
515.3
515.4
555
Technique
GC/ECD
LSE and GC/ECD
LLED and GC/ELCD
LLMED and GC/ECD
HPLC/PDAUVD
Notes: Regulatory DLs for synthetic organic compounds are listed at
Acceptance Criteria for synthetic organic compounds are listed at 40
MDL ug/L
0.21
0.16
0.072-0.14
0.018-
0.033
0.37-1.8
40CFR141.24(h)(18).
CFR141.24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for 2,4,5-TP is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 88). The Six-Year 1 PE data for 2,4,5-TP were not
evaluated in the March 2003 report. Three of the 20 spike values in the Six-Year 1 PE data are
less than the current PQL of 5 |ig/L. No Six-Year 2/ERA data are below the current PQL.
While the passing rates for both data sets are fairly variable, all of the Six-Year 1 passing rates
are above 75% (with the exception of one passing rate that is equal to 75%). One passing rate in
the Six-Year 2/ERA data is below 75%. Both the Six-Year 1 and Six-Year 2/ERA regression
lines are above 75%.
Page 105
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 88: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 2,4,5-TP (Silvex)
in
in
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a.
tn
at
s
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&
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100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 50%
Current PQL
= 5 ug/L
30
90
120
150
True Value (ug/L)
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for 2A5-TP
Given the limited data below the current PQL of 5 |ig/L but generally high laboratory
passing rates (well above 75%) below and in the vicinity of the PQL for the Six-Year 1 data set
and in the vicinity of the PQL for the Six-Year 2/ERA data, a reduction of the PQL may be
considered. The Six-Year 2/ERA data exhibit some variability, with laboratory passing rates in
the vicinity of the PQL ranging from less than 70% to 100%; which may not support the Six-
Year 1 data conclusion that the PQL could be lower. In addition, EPA Method 515.4 has a lower
range of MDLs compared to previously-approved methods. This may lead to an overall
improvement in analytical performance in the vicinity of the current PQL and could suggest
possible reduction of the PQL.
Page 106
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
6.2.3 PQL Assessment Does Not Support Reduction of the Current PQL or Data are
Insufficient to Reach a Conclusion
Of the 41 analytes mentioned in Section 6.2, 24 analytes have an existing PQL that is less
than the MCL and their PE/PT data either indicate that the PQL should not be lower or their
PE/PT data are insufficient to reach a conclusion.
Arsenic
Results of the Methods Comparison
Exhibit 89 summarizes the MDLs for arsenic as documented in EPA-developed
analytical methods. Updates to eight methods have been approved for the analysis of arsenic in
drinking water samples during the years 2000-2007 (see Exhibit A-l). These updates are
associated with administrative and technical changes or clarifications that are not expected to
improve analytical performance near the PQL. The updated methods are proprietary and are not
listed in Exhibit 89.
Exhibit 89: Analytical Methods for Arsenic
MCL = 0.010 mg/L Current PQL = 0.003 mg/L DL = 0.005-0.0014 mg/L
Acceptance Criteria = + 30%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.7
200.8
200.9
Technique
ICP-AES
ICP/MS
GFAA
MDL mg/L
0.008
0.0001 -
0.0014
0.0005
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the POL Analysis
The current PQL for arsenic is 0.003 mg/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 90). The Six-Year 1 PE data for arsenic were not
evaluated in the March 2003 report. Four of the 26 spike values in the Six-Year 1 data set are
below the current PQL of 0.003 mg/L. No Six-Year 2/ERA data are below the current PQL.
With the exception of two spike values, all of the Six-Year 1 passing rates exceed 75%. The low
passing rate just below the PQL is of concern, however. In general, many of the passing rates
around the PQL are highly variable. Furthermore, some of the Six-Year 2/ERA passing rates
above the PQL are below 75%.
Page 107
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
Exhibit 90: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Arsenic
n
in
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a.
in
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&
2
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.Q
100 -
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0.00
75%
Acceptance Criteria
= + 30%
Current PQL
= 0.003 mg/L
0.03
0.06 0.09
True Value (mg/L)
0.12
0.15
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Arsenic
Given the relative lack of data below the current PQL of 0.003 mg/L, the downward trend
in laboratory passing rates below the PQL for the Six-Year 1 data set, and the lack of data in the
vicinity of the PQL for the Six-Year 2/ERA dataset, it may not be appropriate to recommend
lowering of the PQL. No new or revised methods that may be expected to improve analytical
performance in the vicinity of the current PQL (and hence suggest possible reduction of the
PQL) have been approved from 2000-2007.
Page 108
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Beryllium
Results of the Methods Comparison
Exhibit 91 summarizes the MDLs for beryllium as documented in EPA-developed
analytical methods. Updates to five methods have been approved for the analysis of beryllium in
drinking water samples during the years 2000-2007 (see Exhibit A-l). These updates are
associated with administrative and technical changes or clarifications that are not expected to
improve analytical performance near the PQL. The updated methods are proprietary and are not
listed in Exhibit 91.
Exhibit 91: Analytical Methods for Beryllium
MCL = 0.004 mg/L Current PQL = 0.001 mg/L DL = 0.00002-0.0003 mg/L
Acceptance Criteria = + 1 5%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.7
200.8
200.9
Technique
ICP-AES
ICP/MS
GFAA
MDL mg/L
0.0003
0.00002 -
0.0003
0.00002
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the PQL Analysis
The current PQL for beryllium is 0.001 mg/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 92). The Six-Year 1 PE data for beryllium were
regressed as part of the March 2003 report. Four of the 19 spike values in the Six-Year 1 data set
are below the current PQL of 0.001 mg/L. No Six-Year 2/ERA data are below the current PQL
of 0.001 mg/L. The four concentration values from the Six-Year 1 data set that are below the
current PQL also have passing rates of less than 75%. The Six-Year 2/ERA data in the vicinity
of the current PQL have variable passing rates.
Page 109
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 92: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Beryllium
100
in
ra
0.
in
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.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 15%
Current PQL
= 0.001 mg/L
0.000
0.005
0.010 0.015
True Value (mg/L)
0.020
0.025
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Beryllium
Given the relative lack of data and the downward trend in laboratory passing rates below
the current PQL of 0.001 mg/L for the Six-Year 1 data set and the lack of data and high
variability below the PQL for the Six-Year 2/ERA dataset, it may not be appropriate to
recommend lowering of the PQL. No new or revised methods that may be expected to improve
analytical performance in the vicinity of the current PQL (and hence suggest possible reduction
of the PQL) have been approved from 2000-2007.
Page 110
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Cadmium
Results of the Methods Comparison
Exhibit 93 summarizes the MDLs for cadmium as documented in EPA-developed
analytical methods. Updates to one method have been approved for the analysis of cadmium in
drinking water samples during the years 2000-2007 (see Exhibit A-l). These updates are
associated with administrative and technical changes or clarifications that are not expected to
improve analytical performance near the PQL. The updated method is proprietary and is not
listed in Exhibit 93.
Exhibit 93: Analytical Methods for Cadmium
MCL = 0.005 mg/L Current PQL = 0.002 mg/L DL = 0.0001-0.001 mg/L
Acceptance Criteria = + 20%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.7
200.8
200.9
Technique
ICP-AES
ICP/MS
GFAA
MDL mg/L
0.001
0.00003 -
0.0005
0.00005
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the POL Analysis
The current PQL for cadmium is 0.002 mg/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 94). The Six-Year 1 PE data for cadmium were
evaluated but not regressed in the March 2003 report. None of the Six-Year 1 or the Six-Year
2/ERA data are below the current PQL of 0.002 mg/L. However, all of the passing rates, as well
as the two regression lines, are well above 75%.
Page 111
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 94: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Cadmium
O)
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a.
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2
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70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 20%
Current PQL
= 0.002 mg/L
0.000 0.005 0.010
0.015 0.020 0.025 0.030
True Value (mg/L)
0.035
0.040
0.045
0.050
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Cadmium
Although laboratory passing rates are high (well above 75%) for the Six-Year 1 and Six-
Year 2/ERA data sets, given the lack of data below the current PQL of 0.002 mg/L for both data
sets, it may not be appropriate to recommend lowering of the PQL. No new or revised methods
that may be expected to improve analytical performance in the vicinity of the current PQL (and
hence suggest possible reduction of the PQL) have been approved from 2000-2007.
Page 112
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Chromium
Results of the Methods Comparison
Exhibit 95 summarizes the MDLs for chromium as documented in EPA-developed
analytical methods. Updates to three methods have been approved for the analysis of chromium
in drinking water samples during the years 2000-2007 (see Exhibit A-l). These updates are
associated with administrative and technical changes or clarifications that are not expected to
improve analytical performance near the PQL. The updated methods are proprietary and are not
listed in Exhibit 95.
Exhibit 95: Analytical Methods for Chromium
MCL = 0.1 mg/L Current PQL = 0.01 mg/L DL = 0.001-0.007 mg/L
Acceptance Criteria = + 1 5%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.7
200.8
200.9
Technique
ICP-AES
ICP/MS
GFAA
MDL mg/L
0.004
0.00008 -
0.0009
0.0001
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the POL Analysis
The current PQL for chromium is 0.01 mg/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 96). The Six-Year 1 PE data for chromium were
evaluated but not regressed in the March 2003 report. None of the Six-Year 1 or the Six-Year
2/ERA data for chromium are below the current PQL of 0.01 mg/L. However, all of the passing
rates, as well as the two regression lines, are well above 75%.
Page 113
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 96: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Chromium
S
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&
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100
90 -
80 -
70 -
O)
s 6°-
ro
a.
8 50 H
40 -
30 -
20 -
10 -
Jfc!
~
75%
Acceptance Criteria
= + 15%
Current PQL
= 0.01 mg/L
0.00 0.02 0.04 0.06 0.08 0.10 0.12
True Value (mg/L)
0.14
0.16
0.18
0.20
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Chromium
Although laboratory passing rates are high (well above 75%) for the Six-Year 1 and Six-
Year 2/ERA data sets, given the lack of data below the current PQL of 0.01 mg/L for both data
sets, it may not be appropriate to recommend lowering of the PQL. No new or revised methods
that may be expected to improve analytical performance in the vicinity of the current PQL (and
hence suggest possible reduction of the PQL) have been approved from 2000-2007.
Page 114
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Copper
Results of the Methods Comparison
Exhibit 97 summarizes the MDLs for copper as documented in EPA-developed analytical
methods. Updates to six methods have been approved for the analysis of copper in drinking
water samples during the years 2000-2007 (see Exhibit A-l). These updates are associated with
administrative and technical changes or clarifications that are not expected to improve analytical
performance near the PQL. The updated methods are proprietary and are not listed in Exhibit 97.
Exhibit 97: Analytical Methods for Copper
Action Level = 1 .3 mg/L Current PQL = 0.05 mg/L DL = N/A
Acceptance Criteria = + 1 0%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.7
200.8
200.9
Technique
ICP-AES
ICP/MS
GFAA
MDL mg/L
0.003
0.00001 -
0.0005
0.0007
Notes: EPA has not provided a regulatory DL for copper in the CFR. The Acceptance Criteria
for copper are listed at 40 CFR 141 .89(a)(1)(ii)(B).
Results of the POL Analysis
The current PQL for copper is 0.05 mg/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 98). The Six-Year 1 PE data for copper were not evaluated
in the March 2003 report. One of the 19 spike values in the Six-Year 1 data set is below the
current PQL of 0.05 mg/L. No Six-Year 2/ERA data are below the PQL. The single
concentration value less than the PQL corresponds to a passing rate of less than 75%.
Page 115
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 98: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Copper
a.
(0
100
90
80
70
0>
Ģ 60
50
40
30
20
10
75%
Acceptance Criteria
= + 10%
Current PQL
= 0.05 mg/L
0.0 0.2 0.4 0.6 0.8 1.0 1.2
True Value (mg/L)
1.4
1.6
1.8
2.0
ERA Data
PQL
Six-Year 1 Data
75% Passing Rate
Conclusion for Copper
Although laboratory passing rates are high (above 75% just above the PQL) for the Six-
Year 1 and Six-Year 2/ERA data sets, given the lack of data below the current PQL of 0.05 mg/L
for both data sets (with the exception of one laboratory passing rate below 75%), it may not be
appropriate to recommend lowering of the PQL. No new or revised methods that may be
expected to improve analytical performance in the vicinity of the current PQL (and hence
suggest possible reduction of the PQL) have been approved from 2000-2007.
Page 116
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Cyanide
Results of the Methods Comparison
Exhibit 99 summarizes the MDLs for cyanide as documented in EPA-developed
analytical methods. Updates to nine methods and four new methods (Kelada 01, QuikChem 10-
204-00-1-X, OIA-1677 and ASTM D6888-04) have been approved for the analysis of cyanide in
drinking water samples during the years 2000-2007 (67 FR 65220, October 23, 2002, 67 FR
65888, October 29, 2002, 72 FR 11200, March 12, 2007; see Exhibit A-l). While the updates
are associated with administrative and technical changes or clarifications that are not expected to
improve analytical performance near the PQL, the new methods may improve analytical
performance near the PQL; however, because the newly-approved methods are proprietary, the
MDLs/DLs from these methods are not known. In addition, the updated methods are proprietary
and are not listed in Exhibit 99.
Exhibit 99: Analytical Methods for Cyanide
MCL = 0.2 mg/L Current PQL = 0.1 mg/L DL = 0.0005-0.05 mg/L
Acceptance Criteria = + 25%
EPA Methods Approved for the Analysis of Drinking Water
Method
335.4
Technique
Semi-Auto Colorimetry
MDL mg/L
NoMDL
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the POL Analysis
The current PQL for cyanide is 0.1 mg/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 100). The Six-Year 1 PE data for cyanide were not
evaluated in the March 2003 report. One of the 20 spike concentrations from the Six-Year 1 data
set is equal to the PQL; however, none of these data are below the current PQL of 0.1 mg/L. No
Six-Year 2/ERA data are below the current PQL. Several passing rates are below 75%.
Page 117
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 100: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Cyanide
100
O)
_c
'in
in
ra
0.
in
01
c
S
2
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0.0
75%
Acceptance Criteria
= + 25%
Current PQL
= 0.1 mg/L
0.1
0.2
0.3 0.4
True Value (mg/L)
0.5
0.6
0.7
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Cyanide
Given the variable laboratory passing rates for the Six-Year 1 and Six-Year 2/ERA data
sets and the lack of data below the current PQL of 0.1 mg/L for both data sets (with the
exception of one laboratory passing rate from the Six-Year 1 data set just above 75% at the
PQL), it may not be appropriate to recommend lowering of the PQL. Although four new
methods have been approved for the analysis of cyanide, DLs/MDLs are not available for these
methods since they are proprietary. Hence it is not known whether use of these newly-approved
methods could improve laboratory performance at low concentrations and potentially affect the
PQL. While four new methods have been approved for the analysis of cyanide in drinking water,
the methods are proprietary and it is not known whether the DLs and/or MDLs from this method
could lead to an overall improvement in analytical performance in the vicinity of the current
PQL and suggest possible reduction of the PQL.
Page 118
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Dalapon
Results of the Methods Comparison
Exhibit 101 summarizes the MDLs for dalapon as documented in EPA-developed
analytical methods. No updated methods have been approved for the analysis of dalapon in
drinking water samples during the years 2000-2007; however, two new methods, EPA Method
515.4 and EPA Method 552.3 were approved (Federal Register, Vol. 67, No. 209, p. 65888,
October 29, 2002, Federal Register, Vol. 72, No. 47, p. 11200, March 12, 2007; see Exhibit A-
1). The ranges of MDLs for dalapon by EPA Method 515.4 and 552.3 are lower than most of the
MDLs from other methods, which suggests that laboratory performance at low concentrations
may be improved through use of Methods 515.4 and 552.3.
Exhibit 101: Analytical Methods for Dalapon
MCL = 0.2 mg/L Current PQL = 0.01 mg/L DL = 0.001 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
515.1
515.3
515.4
552.1
552.2
552.3
Technique
GC/ECD
LLED and GC/ELCD
LLMED and GC/ECD
I-ELSE/GC w/ ECD
LLED/GC w/ ECD
LLMED/GC w/ ECD
MDL ug/L
1.3
0.53-0.97
0.054 -
0.074
0.32
0.119
0.024-0.14
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141 .24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the POL Analysis
The current PQL for dalapon is 10 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 102). The Six-Year 1 PE data for dalapon were not
evaluated in the March 2003 report. None of the Six-Year 2/ERA data for dalapon are below the
PQL, and passing rates for Six-Year 1 data below the PQL could not be calculated as the
NELAC regression coefficients are not valid over that range. However, all of the passing rates,
as well as the two regression lines, are well above 75%.
Page 119
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 102: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Dalapon
100
in
ra
a.
in
at
S
2
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= Mean+ 2 SD
Current PQL
= 10 ug/L
30
60 90
True Value (ug/L)
120
150
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Dalapon
Although laboratory passing rates are high (above 75%) for the Six-Year 1 and Six-Year
2/ERA data sets, given the lack of data below the current PQL of 10 |ig/L for both data sets, it
may not be appropriate to recommend lowering of the PQL. However, the approval of EPA
Methods 515.4 and 552.3 for the analysis of dalapon provides lower MDLs than were achievable
by use of other approved methods. This may lead to an overall improvement in analytical
performance in the vicinity of the current PQL and could suggest possible reduction of the PQL.
Page 120
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
1,2-Dichlorobenzene
Results of the Methods Comparison
Exhibit 103 summarizes the MDLs for 1,2-dichlorobenzene as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of 1,2-dichlorobenzene in drinking water samples during the years 2000-2007.
Exhibit 103: Analytical Methods for 1,2-Dichlorobenzene
MCL = 0.6mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.02-0.05
0.03-0.05
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the PQL Analysis
The current PQL for 1,2-dichlorobenzene is 5 |ig/L. The Six-Year 1 and Six-Year
2/ERA data sets are regressed separately (see Exhibit 104). The Six-Year 1 PE data for 1,2-
dichlorobenzene were not evaluated in the March 2003 report. Note that the acceptance criteria
are + 40% at spike concentrations below 10 |ig/L and + 20% at or above 10 |ig/L; hence the data
were regressed as two independent populations. None of the Six-Year 1 or the Six-Year 2/ERA
data are below the current PQL of 5 u.g/L. However, all of the passing rates for the two data sets
are well above 75%.
Page 121
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 104: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 1,2-Dichlorobenzene
in
ra
a.
in
100
90 -
80 -
70 -
60 -
50 -
40 -
s
ro
o
3
S? 30 H
20 -
10 -
Acceptance Criteria
= + 40%
Current PQL
= 5 ug/L
^T^
~~~ŧ
75%
Acceptance Criteria
= + 20%
10 15
True Value (ug/L)
20
25
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
-75% Passing Rate
ERA Data At or Above 10 ug/L
Six-Year 1 Data At or Above 10 ug/L
PQL
-10 ug/L Acceptance Criteria Boundary
Conclusion for 1,2-Dichlorobenzene
Although laboratory passing rates are high (well above 75% in the vicinity of the PQL)
for the Six-Year 1 and Six-Year 2/ERA data sets, given the lack of data below the current PQL
of 5 ug/L for both data sets, it may not be appropriate to recommend lowering of the PQL. No
new or revised methods that may be expected to improve analytical performance in the vicinity
of the current PQL (and hence suggest possible reduction of the PQL) have been approved from
2000-2007.
Page 122
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
2,4-Dichlorophenoxyacetic acid (2,4-D)
Results of the Methods Comparison
Exhibit 105 summarizes the MDLs for 2,4-dichlorophenoxyacetic acid as documented in
EPA-developed analytical methods. Updates to one method have been approved for the analysis
of 2,4-D in drinking water samples during the years 2000-2007 (see Exhibit A-l). These updates
are minor technical revisions that are not anticipated to improve analytical performance near the
PQL. In addition, a new method, EPA Method 515.4 was approved (Federal Register, Vol. 67,
No. 209, p. 65888, October 29, 2002; see Exhibit A-l). The MDL for 2,4-D by EPA Method
515.4 is somewhat lower than that obtained from other EPA methods, which suggests that
laboratory performance at low concentrations may be improved through use of Method 515.4.
Exhibit 105: Analytical Methods for 2,4-D
MCL = 0.07 mg/L Current PQL = 0.005 mg/L DL =
Acceptance Criteria = + 50%
0.0001 mg/L
EPA Methods Approved for the Analysis of Drinking Water
Method
515.1
515.2
515.3
515.4
555
Technique
GC/ECD
LSE and GC/ECD
LLED and GC/ELCD
LLMED and GC/ECD
HPLC/PDAUVD
Notes: Regulatory DLs for synthetic organic compounds are listed at
Acceptance Criteria for synthetic organic compounds are listed at 40
MDL ug/L
0.078
0.28
0.35-0.36
0.055 -
0.066
0.34-1.3
40CFR141.24(h)(18).
CFR141.24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for 2,4-D is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets are
regressed separately (see Exhibit 106). The Six-Year 1 PE data for 2,4-D were not evaluated in
the March 2003 report. Only one of the 20 spike values in the Six-Year 1 data set and none of
the Six-Year 2/ERA data are below the current PQL of 5 |ig/L. Several passing rates are below
75%.
Page 123
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 106: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - 2,4-D
100 1
90 -
70 -
O)
8 60
ro
S 50
S
Ģ
o
&
ra
40 -
30 -
20 -
10 -
'. ' '"
^_j j-^VMr^ .
75%
Acceptance Criteria
= + 50 %
Current PQL
= 5 ug/L
30
90
120
150
True Value (ug/L)
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for 2,4-D
Given the variable laboratory passing rates for the Six-Year 1 and Six-Year 2/ERA data
sets and the lack of data below the current PQL of 5 |ig/L for both data sets (with the exception
of one laboratory passing rate from the Six-Year 1 data set just above 75%), it may not be
appropriate to recommend lowering of the PQL. However, the approval of EPA Method 515.4
for the analysis of 2,4-D provides a lower MDL that was achievable by use of other approved
methods. This may lead to an overall improvement in analytical performance in the vicinity of
the current PQL and could suggest possible reduction of the PQL.
Page 124
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Di(2-ethylhexyl)adipate (DEHA)
Results of the Methods Comparison
Exhibit 107 summarizes the MDLs for di(2-ethylhexyl)adipate as documented in EPA-
developed analytical methods. No updated or new analytical methods have been approved for
the analysis of DEHA in drinking water samples during the years 2000-2007.
Exhibit 107: Analytical Methods for Di(2-ethylhexyl)adipate
MCL = 0.4 mg/L Current PQL = 0.006 mg/L DL = 0.0006 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
506
525.2
Technique
LLE or LSE and GC/PID
LSE and CCGC/MS
MDL ug/L
11.82
0.09-1.3
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the POL Analysis
The current PQL for DEHA is 6 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets are
regressed separately (see Exhibit 108). The Six-Year 1 PE data for DEHA were not evaluated in
the March 2003 report. None of the Six-Year 2/ERA data for DEHA are below the current PQL
of 6 u.g/L and passing rates for Six-Year 1 data below the PQL could not be calculated as the
NELAC regression coefficients are not valid over that range. However, all but two of the
passing rates for the two data sets are above 75%.
Page 125
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 108:
100
Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - DEHA
90 -
70 -
S 60
ro
Q_
I 50
"C
s
ro
.Q
ro
40 i
30 H
20 -
10 -
75%
Acceptance Criteria
= Mean + 2 SD
Current PQL
= 6 ug/L
10 15 20 25 30 35 40 45
True Value (ug/L)
50
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for DEHA
Although laboratory passing rates are high (well above 75% in the vicinity of the PQL)
for the Six-Year 1 data set, given the variable laboratory passing rates for the Six-Year 2/ERA
data set and the lack of data below the current PQL of 6 |ig/L for both the Six-Year 1 and Six-
Year 2/ERA data sets, it may not be appropriate to recommend lowering of the PQL. No new or
revised methods that may be expected to improve analytical performance in the vicinity of the
current PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-
2007.
Page 126
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Dinoseb
Results of the Methods Comparison
Exhibit 109 summarizes the MDLs for dinoseb as documented in EPA-developed
analytical methods. No updated methods have been approved for the analysis of dinoseb in
drinking water samples during the years 2000-2007; however, a new method, EPA Method 515.4
was approved (Federal Register, Vol. 67, No. 209, p. 65888, October 29, 2002; see Exhibit A-l).
The MDL range for dinoseb by EPA Method 515.4 is lower than that obtained from other EPA
methods, which suggests that laboratory performance at low concentrations may be improved
through use of Method 515.4.
Exhibit 109: Analytical Methods for Dinoseb
MCL = 0.007 mg/L Current PQL = 0.002 mg/L DL = 0.0002
Acceptance Criteria = Mean + 2 Std Dev
mg/L
EPA Methods Approved for the Analysis of Drinking Water
Method
515.1
515.2
515.3
515.4
555
Technique
GC/ECD
LSE and GC/ECD
LLED and GC/ELCD
LLMED and GC/ECD
HPLC/PDAUVD
MDL ug/L
0.33
0.28
0.75-0.82
0.081 -
0.166
0.26-1.5
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141.24(h)(19)(i)(B).
Results of the POL Analysis
The current PQL for dinoseb is 2 u.g/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 110). The Six-Year 1 PE data for dinoseb were not
evaluated in the March 2003 report. None of the Six-Year 1 or the Six-Year 2/ERA data are
below the current PQL of 2 u.g/L. In general, many of the passing rates around the PQL are
highly variable. Although all of the passing rates in the Six-Year 1 data are above 75%, three
passing rates in the Six-Year 2/ERA data are below 75%.
Page 127
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 110: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Dinoseb
100
90 -
70 -
8 so H
ro
Q.
8 50
S
ra
o
.a
ra
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= Mean+ 2 SD
Current PQL
= 2 ug/L
10 15 20 25 30
True Value (ug/L)
35
40
45
50
ERA Data
PQL
Six- Yea r 1 Data
-75% Passing Rate
Conclusion for Dinoseb
Although laboratory passing rates are high (well above 75% in the vicinity of the PQL)
for the Six-Year 1 data set, given the variable laboratory passing rates for the Six-Year 2/ERA
data set and the lack of data below the current PQL of 2 jig/L for both the Six-Year 1 and Six-
Year 2/ERA data sets, it may not be appropriate to recommend lowering of the PQL. However,
the approval of EPA Method 515.4 for the analysis of dinoseb provides a lower MDL than was
achievable by use of other approved methods. This may lead to an overall improvement in
analytical performance in the vicinity of the current PQL and could suggest possible reduction of
the PQL.
Page 128
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Diquat
Results of the Methods Comparison
Exhibit 111 summarizes the MDLs for diquat as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of diquat in drinking water samples during the years 2000-2007.
Exhibit 111: Analytical Methods for Diquat
MCL = 0.02 mg/L Current PQL = 0.004 mg/L DL = 0.0004 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
549.2
Technique
LSE/HPLC w/ UVD
MDL ug/L
0.72
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141 .24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141.24(h)(19)(i)(B).
Results of the PQL Analysis
The current PQL for diquat is 4 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets are
regressed separately (see Exhibit 112). The Six-Year 1 PE data for diquat were evaluated but
were not regressed in the March 2003 report. None of the Six-Year 1 or the Six-Year 2/ERA
data are below the current PQL of 2 |ig/L. All of the passing rates in the Six-Year 1 data are
above 75%; meanwhile, five passing rates in the Six-Year 2/ERA data are less than or equal to
75%.
Page 129
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 112: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Diquat
in
ra
a.
in
&
2
o
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= Mean + 2 SD
Current PQL
= 4 ug/L
10 15 20 25
True Value (ug/L)
30
35
40
45
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Diquat
Although laboratory passing rates are high (above 75% in the vicinity of the PQL) for the
Six-Year 1 data set, given the variable laboratory passing rates for the Six-Year 2/ERA data set
and the lack of data below the current PQL of 4 jig/L for both the Six-Year 1 and Six-Year
2/ERA data sets, it may not be appropriate to recommend lowering of the PQL. No new or
revised methods that may be expected to improve analytical performance in the vicinity of the
current PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-
2007.
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Endothatt
Results of the Methods Comparison
Exhibit 113 summarizes the MDLs for endothall as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of endothall in drinking water samples during the years 2000-2007.
Exhibit 113: Analytical Methods for Endothall
MCL = 0.1 mg/L Current PQL = 0.09 mg/L DL = 0.009 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
548.1
Technique
l-EE/Methylate and GC/MS
MDL ug/L
0.7-1.79
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the PQL Analysis
The current PQL for endothall is 90 u.g/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 114). The Six-Year 1 PE data for endothall were not
evaluated in the March 2003 report. None of the Six-Year 2/ERA data for endothall are below
the PQL and passing rates for Six-Year 1 data below the PQL could not be calculated as the
NELAC regression coefficients are not valid over that range. All but one of the passing rates in
the Six-Year 1 data are above 75%; meanwhile, four passing rates in the Six-Year 2/ERA data
are less than or equal to 75%. Note that the 0% passing rate near 220 ug/L from the Six-Year 1
data was a study that consisted of only one laboratory.
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 114: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Endothall
100
in
ra
a.
in
at
S
2
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= Mean + 2SD
Current PQL
= 90 ug/L
50 100 150 200 250 300
True Value (ug/L)
350
400
450
500
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Endothall
Although laboratory passing rates are high (well above 75% in the vicinity of the PQL)
for the Six-Year 1 data set, given the variable laboratory passing rates for the Six-Year 2/ERA
data set and the lack of data below the current PQL of 90 |ig/L for both the Six-Year 1 and Six-
Year 2/ERA data sets, it may not be appropriate to recommend lowering of the PQL. No new or
revised methods that may be expected to improve analytical performance in the vicinity of the
current PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-
2007.
Page 132
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Endrin
Results of the Methods Comparison
Exhibit 115 summarizes the MDLs for endrin as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of endrin in drinking water samples during the years 2000-2007.
Exhibit 115: Analytical Methods for Endrin
MCL = 0.002 mg/L Current PQL = 0.0001 mg/L DL = 0.00001 mg/L
Acceptance Criteria = + 30%
EPA Methods
Method
505
508
508.1
525.2
551.1
Approved for the Analysis of Drinking Water
Technique
ME and GC
GC/ECD
LSE and ECGC
LSE and CCGC/MS
LLE/GC w/ ECD
MDL ug/L
0.063
0.0062
0.007
0.16-0.34
0.002 -
0.003
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141 .24(h)(19)(i)(B).
Results of the PQL Analysis
The current PQL for endrin is 0.1 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 116). The Six-Year 1 PE data for endrin were not evaluated
in the March 2003 report. None of the Six-Year 1 or the Six-Year 2/ERA data are below the
current PQL of 0.1 |ig/L. One passing rate for the Six-Year 1 data is below 75%; however, the
Six-Year 2/ERA passing rates are more variable, with several passing rates below 75%.
Page 133
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 116: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Endrin
100
O)
o
Ģ1
ra
90 -
70 -
S 60
ro
Q.
I 50
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 30%
Current PQL
= 0.1 ug/L
234
True Value (ug/L)
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Endrin
Given the variable laboratory passing rates in the vicinity of the current PQL of 0.1 |ig/L
and the lack of data below the current PQL for both the Six-Year 1 and Six-Year 2/ERA data
sets, it may not be appropriate to recommend lowering of the PQL. No new or revised methods
that may be expected to improve analytical performance in the vicinity of the current PQL (and
hence suggest possible reduction of the PQL) have been approved from 2000-2007.
Page 134
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Fluoride
Results of the Methods Comparison
Exhibit 117 summarizes the MDLs for fluoride as documented in EPA-developed analytical
methods. Updates to eleven methods and two new methods (EPA Method 300.1 and ASTM
D6508, rev. 2) have been approved for the analysis of fluoride in drinking water samples during
the years 2000-2007 (Federal Register, Vol. 72, No. 47, p. 11200, March 12, 2007; see Exhibit
A-l). The updates are associated with administrative and technical changes or clarifications that
are not expected to improve analytical performance near the PQL. The updated methods are
proprietary and are not listed in Exhibit 117. The MDL for EPA Method 300.1 is slightly lower
than that for EPA Method 300.0, which suggests that laboratory performance at low
concentrations may be improved through use of Method 300.1. Since the new ASTM method is
proprietary, it is uncertain whether new MDLs may be lower than those for other methods.
Exhibit 117: Analytical Methods for Fluoride
MCL = 4
EPA Methods
Method
300.0
300.1
mg/L Current PQL = 0.5 mg/L
Acceptance Criteria = + 1 0%
Approved for the Analysis of
DL= N/A
Drinking Water
Technique
1C
1C
MDL mg/L
0.01
0.009
Notes: EPA has not provided a regulatory DL for fluoride in the CFR. Acceptance Criteria for
inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the PQL Analysis
The current PQL for fluoride is 0.5 mg/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 118). The Six-Year 1 PE data for fluoride were evaluated
but were not regressed as part of the March 2003 report. One of the 20 spike values in the Six-
Year 1 data set is below the current PQL of 0.5 mg/L. No Six-Year 2/ERA data are below the
current PQL. All but one of the Six-Year 1 passing rates are above 75%. Furthermore, two of
the Six-Year 2/ERA passing rates are below 75%.
Page 135
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 118: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Fluoride
100
90 -
70 -
8 60 H
ro
a.
SS 50
40 -
S
Ģ
o
.a
ra
i? 30-
20 -
10 -
75%
Acceptance Criteria
= + 10%
Current PQL
= 0.5 mg/L
345
True Value (mg/L)
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Fluoride
Given the variable laboratory passing rates for the Six-Year 1 and Six-Year 2/ERA data
sets in the vicinity of the current PQL of 0.5 mg/L and the lack of data below the PQL for both
data sets (with the exception of one laboratory passing rate from the Six-Year 1 data set slightly
below the PQL), it may not be appropriate to recommend lowering of the PQL. However, the
approval of EPA Method 300.1 for the analysis of fluoride provides a slightly lower MDL than
was achievable by use of other approved methods. This may lead to a slight improvement in
analytical performance in the vicinity of the current PQL and could suggest possible reduction of
the PQL.
Page 136
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Glyphosate
Results of the Methods Comparison
Exhibit 119 summarizes the MDLs for glyphosate as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of glyphosate in drinking water samples during the years 2000-2007.
Exhibit 119: Analytical Methods for Glyphosate
MCL = 0.7 mg/L Current PQL = 0.06 mg/L DL = 0.006 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
547
Technique
DAI/HPLC w/ Der. and FD
MDL ug/L
5.99-6.00
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 141 .24(h)(19)(i)(B).
Results of the PQL Analysis
The current PQL for glyphosate is 60 u.g/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 120). The Six-Year 1 PE data for glyphosate were
evaluated but not regressed in the March 2003 report. None of the Six-Year 1 or the Six-Year
2/ERA data are below the current PQL of 60 |ig/L. All but one of the passing rates in the Six-
Year 1 data are above 75%; however, several passing rates in the Six-Year 2/ERA data are less
than or equal to 75%.
Page 137
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 120: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Glyphosate
n
in
ra
a.
in
o
2
o
.a
ra
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= Mean + 2 SD
Current PQL
= 60 ug/L
100 200 300 400 500
True Value (ug/L)
600
700
800
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Glyphosate
Given the variable laboratory passing rates for the Six-Year 2/ERA data set and the lack
of data below or in the vicinity of the current PQL of 60 |ig/L for both the Six-Year 1 and Six-
Year 2/ERA data sets, it may not be appropriate to recommend lowering of the PQL. No new or
revised methods that may be expected to improve analytical performance in the vicinity of the
current PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-
2007.
Page 138
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Lead
Results of the Methods Comparison
Exhibit 121 summarizes the MDLs for lead as documented in EPA-developed analytical
methods. Updates to three methods have been approved for the analysis of lead in drinking
water samples during the years 2000-2007 (see Exhibit A-l). These updates are associated with
administrative and technical changes or clarifications that are not expected to improve analytical
performance near the PQL. The updated methods are proprietary and are not listed in Exhibit
121.
Exhibit 121: Analytical Methods for Lead
Action Level = 0.015 mg/L Current PQL = 0.005 mg/L DL = 0.001 mg/L
Acceptance Criteria = + 30%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.8
200.9
Technique
ICP/MS
GFAA
MDL mg/L
0.00002 -
0.0006
0.0007
Notes: The regulatory DL for lead is listed at 40 CFR 141 .89(a)(1)(iii). Note that the DL is
referred to as the "method detection limit" in the CFR. The Acceptance Criteria for lead are
listed at 40 CFR 141.89(a)(1)(ii)(A).
Results of the POL Analysis
The current PQL for lead is 5 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets are
regressed separately (see Exhibit 122). The Six-Year 1 PE data for lead were not evaluated in
the March 2003 report. Four of the 20 spike values in the Six-Year 1 data set are less than or
equal to the current PQL of 5 |ig/L. No Six-Year 2/ERA data are below the PQL. Three of the
Six-Year 1 concentration values had passing rates of less than 75%.
Page 139
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 122: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Lead
O)
_c
'in
in
ra
0.
in
01
c
S
o
.a
ra
100
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 30%
Current PQL
= 5 ug/L
10 20 30 40 50 60
True Value (ug/L)
70
90
100
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Lead
Given the relative lack of data and the downward trend in laboratory passing rates below
the current PQL of 5 |ig/L for the Six-Year 1 data set and the lack of data below the PQL for the
Six-Year 2/ERA dataset, it may not be appropriate to recommend lowering of the PQL. No new
or revised methods that may be expected to improve analytical performance in the vicinity of the
current PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-
2007.
Page 140
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Mercury
Results of the Methods Comparison
Exhibit 123 summarizes the MDLs for mercury as documented in EPA-developed analytical
methods. Updates to three methods have been approved for the analysis of mercury in drinking
water samples during the years 2000-2007 (see Exhibit A-l). These updates are associated with
administrative and technical changes or clarifications that are not expected to improve analytical
performance near the PQL. The updated methods are proprietary and are not listed in Exhibit
123. However, a new method, EPA Method 245.7, rev. 2.0, was approved (Federal Register,
Vol. 72, No. 47, p. 11200, March 12, 2007; see Exhibit A-l). The MDL from this method is
significantly lower than the MDLs from other methods, suggesting that laboratory performance
at low concentrations may improve through use of Method 245.7.
Exhibit 123: Analytical Methods for Mercury
MCL = 0.002 mg/L Current PQL = 0.0005 mg/L DL = 0.0002 mg/L
Acceptance Criteria = + 30%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.8
245.1
245.2
245.7
Technique
ICP/MS
CVAAS
ACVT
CVAFS
MDL mg/L
0.0002
No MDL
No MDL
0.0000018
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the PQL Analysis
The current PQL for mercury is 0.0005 mg/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 124). The Six-Year 1 PE data for mercury were
evaluated but not regressed in the March 2003 report. None of the Six-Year 1 or the Six-Year
2/ERA data are below the current PQL of 0.0005 mg/L. (One of the Six-Year 1 values is equal
to 0.000506 mg/L, just above the PQL.) All but one of the passing rates in the Six-Year 1 data
set and all of the passing rates in the Six-Year 2/ERA data set are above 75%.
Page 141
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
Exhibit 124: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Mercury
100
O)
_c
'in
in
ra
0.
in
01
c
S
2
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 30%
Current PQL
= 0.0005 mg/L
0.000 0.001 0.002 0.003 0.004 0.005
True Value (mg/L)
0.006
0.007
0.008
0.009
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Mercury
Given the variable laboratory passing rates the vicinity of the current PQL of 0.5 mg/L
for the Six-Year 1 data set and the lack of data below the PQL for both the Six-Year 1 and Six-
Year 2/ERA data sets (with the exception of one laboratory passing rate from the Six-Year 1 data
set just below the PQL), it may not be appropriate to recommend lowering of the PQL.
However, the approval of EPA Method 245.7 (Rev 2.0) for the analysis of mercury provides a
significantly lower MDL than was achievable by use of other approved methods. This may lead
to an overall improvement in analytical performance in the vicinity of the current PQL and could
suggest possible reduction of the PQL.
Page 142
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Nitrate (as N)
Results of the Methods Comparison
Exhibit 125 summarizes the MDLs for nitrate as documented in EPA-developed analytical
methods. Updates to ten methods and two new methods (EPA Method 300.1 and ASTM D6508,
rev. 2) have been approved for the analysis of nitrate in drinking water samples during the years
2000-2007 (Federal Register, Vol. 67, No. 205, p. 65220, October 23, 2002; Federal Register,
Vol. 72, No. 47, p. 11200, March 12, 2007; see Exhibit A-l). The updates are associated with
administrative and technical changes or clarifications that are not expected to improve analytical
performance near the PQL. The updated methods are proprietary and are not listed in Exhibit
125. In addition, MDL data for nitrate by EPA Method 300.1 indicate a higher MDL than is
obtained from EPA Method 300.0, which does not suggest that laboratory performance at low
concentrations may be improved through use of Method 300.1.
Exhibit 125: Analytical Methods for Nitrate
MCL = 1 0 mg/L Current PQL = 0.4 mg/L DL = 0.01 -1 mg/L
Acceptance Criteria = + 1 0%
EPA Methods Approved for the Analysis of Drinking Water
Method
300.0
300.1
353.2
Technique
1C
1C
Auto Colorimetry
MDL mg/L
0.002
0.008
No MDL
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the POL Analysis
The current PQL for nitrate is 0.4 mg/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 126). The Six-Year 1 PE data for nitrate were not evaluated
in the March 2003 report. None of the Six-Year 1 or the Six-Year 2/ERA data are below the
current PQL of 0.4 mg/L, although several of the Six-Year 1 values are just above the PQL.
Several of the passing rates (especially in the Six-Year 1 data set) are below 75%.
Page 143
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 126: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Nitrate
in
ra
a.
in
at
Ģ
2
o
ra
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 10%
Current PQL
= 0.4mg/L
6 8 10
True Value (mg/L)
12
14
16
ERA Data
PQL
Six-Yea r1 Data
-75% Passing Rate
Conclusion for Nitrate
Given the variable laboratory passing rates for the Six-Year 1 and Six-Year 2/ERA data
sets and the lack of data below the current PQL of 0.4 mg/L for both data sets, it may not be
appropriate to recommend lowering of the PQL. No new or revised methods that may be
expected to improve analytical performance in the vicinity of the current PQL (and hence
suggest possible reduction of the PQL) have been approved from 2000-2007.
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Oxamyl (Vydate)
Results of the Methods Comparison
Exhibit 127 summarizes the MDLs for oxamyl as documented in EPA-developed
analytical methods. No updated methods have been approved for the analysis of oxamyl in
drinking water samples during the years 2000-2007; however, a new method, EPA Method
531.2, was approved (Federal Register, Vol. 67, No. 209, p. 65888, October 29, 2002; see
Exhibit A-l). The range of DLs for oxamyl by EPA Method 531.2 are lower than the MDL from
EPA Method 531.1, suggesting that laboratory performance at low concentrations may improve
through use of Method 531.2.
Exhibit 127: Analytical Methods for Oxamyl
MCL = 0.2 mg/L Current PQL = 0.02 mg/L DL = 0.002 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
531.1
531.2
Technique
DAI/HP LC w/ Der.
DAI/HP LC w/ Der.
MDL ug/L
0.86
0.044 -
0.065 (DL)
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141 .24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the POL Analysis
The current PQL for oxamyl is 20 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 128). The Six-Year 1 PE data for oxamyl were regressed as
part of the March 2003 report. Seven of the 20 spike values in the Six-Year 1 data set are below
the current PQL of 20 |ig/L; however, none of the Six-Year 2/ERA data are below the current
PQL. Passing rates, particularly in the Six-Year 1 data, are highly variable.
Page 145
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 128: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Oxamyl
n
in
ra
a.
in
o
2
o
.a
ra
100
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= Mean + 2 SD
Current PQL
= 20 ug/L
10
20
30 40 50
True Value (ug/L)
60
70
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Oxatnyl
Given the variable laboratory passing rates in the vicinity of the current PQL of 20 |ig/L
for the Six-Year 1 and Six-Year 2/ERA data sets and the lack of data below the PQL for the Six-
Year 2 data set, it may not be appropriate to recommend lowering of the PQL. The approval of
EPA Method 531.2 for the analysis of oxamyl provides a lower range of MDLs than was
achievable by use of other approved methods. This may lead to an overall improvement in
analytical performance in the vicinity of the current PQL and could suggest possible reduction of
the PQL.
Page 146
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Picloram
Results of the Methods Comparison
Exhibit 129 summarizes the MDLs for picloram as documented in EPA-developed
analytical methods. Updates to one method have been approved for the analysis of picloram in
drinking water samples during the years 2000-2007 (see Exhibit A-l). These updates are minor
technical revisions that are not anticipated to improve analytical performance near the PQL. In
addition, a new method, EPA Method 515.4 was approved (Federal Register, Vol. 67, No. 209,
p. 65888, October 29, 2002; see Exhibit A-l). The MDL for picloram by EPA Method 515.4 is
lower than those obtained from other approved methods, suggesting that laboratory performance
at low concentrations may improve through use of Method 515.4.
Exhibit 129: Analytical Methods for Picloram
MCL = 0.5 mg/L Current PQL = 0.001 mg/L DL = 0.0001 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
515.1
515.2
515.3
515.4
555
Technique
GC/ECD
LSE and GC/ECD
LLED and GC/ELCD
LLMED and GC/ECD
HPLC/PDAUVD
MDL ug/L
0.15
0.35
0.47-1.0
0.055-
0.076
Not
Recovered -
0.5
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the POL Analysis
The current PQL for picloram is 1 u.g/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 130). The Six-Year 1 PE data for picloram were evaluated
but not regressed in the March 2003 report. None of the Six-Year 1 or the Six-Year 2/ERA data
are below the current PQL of 1 |ig/L. The passing rates begin to drop below 75% approaching
the PQL.
Page 147
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit 130: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Picloram
100
O)
_c
'in
in
ra
a.
in
01
c
S
o
.a
ra
90 -
80 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= Mean + 2 SD
Current PQL
= 1 ug/L
10
20
30 40 50
True Value (ug/L)
60
70
80
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Picloram
Although the laboratory passing rates for both the Six-Year 1 and Six-Year 2/ERA data
sets are generally high, given the lower laboratory passing rates in the vicinity of the current
PQL of 1 |ig/L and the lack of data below the PQL for both data sets, it may not be appropriate
to recommend lowering of the PQL. However, the approval of EPA Method 515.4 for the
analysis of picloram provides a lower MDL than was achievable by use of other approved
methods. This may lead to an overall improvement in analytical performance in the vicinity of
the current PQL and could suggest possible reduction of the PQL.
Page 148
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Selenium
Results of the Methods Comparison
Exhibit 131 summarizes the MDLs for selenium as documented in EPA-developed
analytical methods. Updates to four methods have been approved for the analysis of selenium in
drinking water samples during the years 2000-2007 (see Exhibit A-l). These updates are
associated with administrative and technical changes or clarifications that are not expected to
improve analytical performance near the PQL.
Exhibit 131: Analytical Methods for Selenium
MCL = 0.05 mg/L Current PQL = 0.01 mg/L DL = 0.002 mg/L
Acceptance Criteria = + 20%
EPA Methods Approved for the Analysis of Drinking Water
Method
200.8
200.9
Technique
ICP/MS
GFAA
MDL mg/L
0.0005 -
0.0079
0.0006
Notes: Regulatory DLs for inorganic compounds are listed at 40 CFR 141 .23(a)(4)(i).
Acceptance Criteria for inorganic compounds are listed at 40 CFR 141 .23(k)(3)(ii).
Results of the PQL Analysis
The current PQL for selenium is 0.01 mg/L. The Six-Year 1 and Six-Year 2/ERA data
sets are regressed separately (see Exhibit 132). The Six-Year 1 PE data for selenium were not
evaluated in the March 2003 report. Only one of the 20 spike values in the Six-Year 1 data set is
below the current PQL of 0.01 mg/L. No Six-Year 2/ERA data are below the current PQL. All
of the passing rates are well above 75%. Furthermore, both regression lines are also well above
75%.
Page 149
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit 132: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Selenium
100
in
ra
0.
in
01
c
S
2
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= + 20%
Current PQL
= 0.01 mg/L
0.00 0.01 0.02 0.03 0.04 0.05 0.06
True Value (mg/L)
0.07
0.08
0.09
0.10
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Selenium
Although the laboratory passing rates for both the Six-Year 1 and Six-Year 2/ERA data
sets are generally high, given the lack of data below the PQL of 0.01 mg/L for both data sets
(with the exception of one value from the Six-Year 1 data set just below the PQL), it may not be
appropriate to recommend lowering of the PQL. No new or revised methods that may be
expected to improve analytical performance in the vicinity of the current PQL (and hence
suggest possible reduction of the PQL) have been approved from 2000-2007.
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Simazine
Results of the Methods Comparison
Exhibit 133 summarizes the MDLs for simazine as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of simazine in drinking water samples during the years 2000-2007.
Exhibit 133: Analytical Methods for Simazine
MCL = 0.004 mg/L Current PQL = 0.0007 mg/L DL = 0.00007 mg/L
Acceptance Criteria = Mean + 2 Std Dev
EPA Methods Approved for the Analysis of Drinking Water
Method
505
507
508.1
525.2
551.1
Technique
ME and GC
GC/N-PD
LSE and ECGC
LSE and CCGC/MS
LLE/GC w/ ECD
MDL ug/L
6.8
0.014
0.008
0.045-0.18
0.121 -
0.187
Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141 .24(h)(18).
Acceptance Criteria for synthetic organic compounds are listed at 40 CFR 1 41 .24(h)(1 9)(i)(B).
Results of the PQL Analysis
The current PQL for simazine is 0.7 |ig/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 134). The Six-Year 1 PE data for simazine were not
evaluated in the March 2003 report. None of the Six-Year 2/ERA data are below the current
PQL of 0.7 |ig/L and passing rates for Six-Year 1 data below the PQL could not be calculated as
the NELAC regression coefficients are not valid over that range. All of the passing rates in the
Six-Year 1 data are above 75%; however, several passing rates in the Six-Year 2/ERA data are
less than or equal to 75%.
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Exhibit 134: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Simazine
n
in
ra
a.
in
o
2
o
&
ra
100
90 -
80
70
60 -
50 -
40 -
30 -
20 -
10 -
75%
Acceptance Criteria
= Mean + 2 SD
Current PQL
= 0.7 ug/L
10 15 20 25
True Value (ug/L)
30
35
40
ERA Data
PQL
Six-Year 1 Data
-75% Passing Rate
Conclusion for Simazine
Although the laboratory passing rates for the Six-Year 1 data set are generally high (well
above 75%), given the lack of data below the PQL of 0.7 |ig/L for both the Six-Year 1 and Six-
Year 2/ERA data sets and the variability in laboratory passing rates in the vicinity of the PQL for
the Six-Year 2 data set, it may not be appropriate to recommend lowering of the PQL. No new
or revised methods that may be expected to improve analytical performance in the vicinity of the
current PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-
2007.
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Xylenes (total)
Results of the Methods Comparison
Exhibit 135 summarizes the MDLs for xylenes as documented in EPA-developed
analytical methods. No updated or new analytical methods have been approved for the analysis
of xylenes in drinking water samples during the years 2000-2007.
Exhibit 135: Analytical Methods for Xylenes
MCL = 1 0 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Acceptance Criteria = + 20% or 40%
EPA Methods Approved for the Analysis of Drinking Water
Method
502.2
524.2
Technique
CCGCwithPID/ELCD
CCGC/MS
MDL ug/L
0.01 -0.02
0.03-0.13
Notes: The regulatory DL for volatile organic compounds is listed at 40 CFR
141.24(k)(17)(ii)(C). Acceptance Criteria for volatile organic compounds are listed at 40 CFR
141.24(f)(17)(i).
Results of the POL Analysis
The current PQL for xylenes is 5 u.g/L. The Six-Year 1 and Six-Year 2/ERA data sets
are regressed separately (see Exhibit 136). The Six-Year 1 PE data for xylenes were evaluated
but were not regressed as part of the March 2003 report. Note that the acceptance criteria are +
40% at spike concentrations below 10 jig/L and + 20% at or above 10 u.g/L; hence the data are
regressed as two independent populations. No Six-Year 1 data are available below the current
PQL of 5 |ig/L. Only one of the 60 spike values in the Six-Year 2/ERA data set is below the
current PQL. All of the passing rates for the Six-Year 1 data set are above 75%; however the
passing rates for the Six-Year 2/ERA data set are more variable.
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Exhibit 136: Evaluation of Six-Year 1 and Six-Year 2/ERA PT Data - Xylenes
in
ra
a.
in
01
c
S
o
&
ra
100
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
Acceptance Criteria
= + 40%
Acceptance Criteria
= + 20%
75%
Current PQL
= 5 ug/L
10 15 20 25 30
True Value (ug/L)
35
40
45
50
ERA Data Below 10 ug/L
Six-Year 1 Data Below 10 ug/L
75% Passing Rate
ERAData AtorAbove 10 ug/L
Six-Year 1 Data AtorAbove 10 ug/L
PQL
10 ug/L Acceptance Criteria Boundary
Conclusion for Xylenes
Although the laboratory passing rates for the Six-Year 1 data set are generally high (well
above 75%), given the lack of data below the PQL of 5 |ig/L for the Six-Year 1 data set and the
variability in laboratory passing rates for the Six-Year 2 data set, it may not be appropriate to
recommend lowering of the PQL. No new or revised methods that may be expected to improve
analytical performance in the vicinity of the current PQL (and hence suggest possible reduction
of the PQL) have been approved from 2000-2007.
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7.0 Summary
This document examines analytical method performance over time by determining if the
Practical Quantitation Levels (PQLs) may have changed since promulgation. PQL assessments
are presented by means of linear regression of available Six-Year 1 data and the ERA dataset
from Six-Year 2. A qualitative conclusion is drawn by presenting a recommendation of whether
a PQL might be reduced. In addition, analytical method performance is also assessed by
comparing the Method Detection Limits (MDLs) of the analytical methods which were available
at the time of promulgation to those of the currently approved methods.
Exhibit 137 provides summary observations from this review of PE data that were
compiled in the first Six-Year Review and of ERA's 1999-2004 PT data. It also includes a
notation as to whether any recently-approved analytical methods or updates (i.e., from 2000-
2007) are available for these analytes that might indicate improved laboratory performance at
low concentrations. Lastly, a recommendation as to whether a PQL can be reduced is provided
(these analytes are italicized). Note that the entries in the "Current Evaluation of Six-Year 1
Data" column are not necessarily identical to the conclusions that were documented in the March
2003 report. Rather, a new assessment is made herein considering the advantages and
disadvantages of the PQL concept, the availability of PE/PT data in the vicinity of and/or below
the PQL, and outliers. The qualitative conclusions are based primarily on data that are in the
vicinity of and/or below the PQL (for most of the VOCs, this corresponds to concentrations <10
Hg/L). Only the current evaluations of the Six-Year 1 and Six-Year 2/ERA data are presented in
this report.
The overall assessment decision presented in the final column of Exhibit 137 consists of
the following possible outcomes:
Regulated Contaminants with Existing PQL Lower than the MCL
- PQL assessment supports reduction of the current PQL;
PQL assessment may support reduction of the current PQL; and
PQL assessment does not support reduction of the current PQL, or data are
inconclusive or insufficient to reach a conclusion
Regulated Contaminants for Which the MCL is Set at the PQL, and thus, the PQL is
Limiting
- PQL assessment supports reduction of the current PQL;
PQL assessment may support reduction of the current PQL; and
PQL assessment does not support reduction of the current PQL, or data are
inconclusive or insufficient to reach a conclusion.
The recommendation to not reduce the PQL/MCL (or not to reduce it further in cases
where the PQL < MCL) could be related to many factors, since each of the Six-Year 1 and ERA
data sets may reflect one or more of the following traits:
No PE/PT data are available at or below the PQL;
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Laboratory performance is poor near the PQL;
Laboratory performance is highly variable over the range of concentrations analyzed.
The data sets may suggest entirely opposite recommendations, in that one data set may
suggest that the PQL could be reduced while the other may suggest the opposite. Hence there is
no simple, succinct way to reflect the reason why a recommendation of "No change to the PQL"
was obtained, although a lack of data at or below the PQL for both data sets implies that the data
are insufficient to support a reduction in the PQL. However, in a case such as this, laboratory
performance across the range of concentrations analyzed is still a contributing factor in the
recommendation.
As shown in Exhibit 137, of the 66 analytes that could be analyzed in this report
(acrylamide, epichlorohydrin, 2,3,7,8-TCDD (dioxin) could not be analyzed due to a lack of
PE/PT data, and chlorite has no PQL), the qualitative recommendations for PQL assessment
break down as follows:
For 25 analytes, the PQL is equal to the MCL and hence PQL is limiting. Of these 25
analytes, PQL assessment indicates that:
- The PQL can be reduced for 9 analytes: benzene, carbon tetrachloride, chlordane,
1,2-dichloroethane, 1,2-dichloropropane, hexachlorobenzene, tetrachloroethylene,
1,1,2-trichloroethane, and trichloroethylene;
- The PQL might be considered for reduction for 8 analytes: alachlor, antimony, 1,2-
dibromo-3-chloropropane, heptachlor, heptachlor epoxide, lindane, toxaphene, and
vinyl chloride; and
- PE/PT data do not support reduction of the PQL or data are inconclusive or
insufficient to reach a conclusion for 8 analytes: benzo(a)pyrene, bromate,
dichloromethane, di(2-ethylhexyl)phthalate, ethylene dibromide, pentachlorophenol,
polychlorinatedbiphenyls (PCBs), and thallium.
For 41 analytes, the PQL is less than the MCL; hence the MCL can be reduced. For these
41 analytes, PQL assessment indicates that:
- The PQL can be reduced further (beyond the current PQL) for 11 analytes: barium,
1,4-dichlorobenzene, c/5-l,2-dichloroethylene, 1,1-dichloroethylene, ethylbenzene,
monochlorobenzene, nitrite, styrene, toluene, 1,2,4-trichlorobenzene, and 1,1,1-
trichloroethane;
- The PQL might be considered for further reduction for 6 analytes: atrazine,
carbofuran, fram'-l,2-dichloroethylene, hexachlorocyclopentadiene, methoxychlor,
and 2,4,5-TP (Silvex); and
- PE/PT data do not support further reduction of the PQL or data are inconclusive or
insufficient to reach a conclusion for 24 analytes: arsenic, beryllium, cadmium,
chromium, copper, cyanide, dalapon, 1,2-dichlorobenzene, 2,4-dichlorophenoxyacetic
acid, di(2-ethylhexyl)adipate, dinoseb, diquat, endothall, endrin, fluoride, glyphosate,
lead, mercury, nitrate, oxamyl, picloram, selenium, simazine, and xylenes.
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Several factors often require that these assessments be made qualitatively rather than
quantitatively. The regression of PE/PT data vs. passing rate can be affected by high passing
rates even when there are also passing rates that are well below the 75% threshold (e.g., a large
number of passing rates >90% will "offset" passing rates below 75%, resulting in a regression
line that is well above 75% across the range of spike concentrations). Thus, even when the
regression line is above the 75% passing rate threshold, a few relatively low passing rates,
particularly near the PQL, may be considered to be more important than much higher passing
rates at other concentrations. In some cases, the recommendation resulting from the Six-Year 1
data set is opposite from that resulting from the ERA data set. In these cases, the more recent
ERA data may drive the recommendation. The variable acceptance criteria (based on analyte
concentration) for several analytes (most of the VOCs) also confound the issue. In these cases,
the passing rates below 10 jig/L are often much higher than those at or above 10 |ig/L. Passing
rates of less than 75% may occur above 10 |ig/L, while much higher passing rates are often
observed below 10 |ig/L.
Exhibits 137 and 138 summarize the qualitative assessment for potential PQL reduction
for the Six-Year 1 and Six-Year 2/ERA datasets individually and include a final qualitative
recommendation considering both datasets. These exhibits also include an indication of whether
new or updated analytical methods might be expected to improve analytical performance in the
vicinity of the current PQL. Exhibit 137 summarizes the PQL assessments for the 25 analytes
that have an MCL set at the current PQL, and thus the PQL is limiting. Exhibit 138 summarizes
the PQL assessments for the 41 analytes that have an MCL that is greater than the current PQL,
and thus it is technically feasible to reduce an MCL. Analytical method performance assessment
for these analytes can indicate the potential for MCL reduction beyond the current PQL.
Exhibit 137: Second Six-Year Review Analytical Feasibility Assessment Summary
Analytes with MCL Equal to the Current PQL, and thus the PQL is Limiting - 25 Analytes
Analyte
Alachlor
Antimony
Benzene
Current
PQL
(mg/L)
0.002
0.006
0.005
New or Updated
Methods?
No
Yes - not expected
to improve
analytical
performance in
vicinity of current
PQL
No
PQL Assessment Results
Current
Evaluation of
Six-Year 1
Data
Data may
support lower
PQL
Data may
support lower
PQL
Data support
lower PQL
Current
Evaluation of
Six-Year 2
(ERA 1999-
2004) Data
No data <
current PQL;
passing rates
high in vicinity
of current PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
Data support
lower PQL
Overall Qualitative
Recommendation
Reduction of current PQL may
be supported
Slight reduction of current PQL
may be supported
Reduction of current PQL
supported
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Analyte
Benzo(a)pyrene
Bromate
Carbon tetrachloride
Chlordane
1,2-Dibromo-3-
chloropropane (DBCP)
1,2-Dichloroethane
(Ethylene dichloride)
Dichloromethane
(Methylene Chloride)
1,2-Dichloropropane
Di(2-ethylhexyl) phthalate
(DEHP)
Ethylene Dibromide
(EDB)
Heptachlor
Heptachlor epoxide
Hexachlorobenzene
Lindane
Current
PQL
(mg/L)
0.0002
0.01
0.005
0.002
0.0002
0.005
0.005
0.005
0.006
0.00005
0.0004
0.0002
0.001
0.0002
New or Updated
Methods?
No
Yes- may improve
analytical
performance in
vicinity of current
PQL. New
methods 317.0 and
326.0 have lower
MDLs.
No
No
No
No
No
No
No
No
No
No
No
No
PQL Assessment Results
Current
Evaluation of
Six-Year 1
Data
No data <
current PQL
Data indicate no
change to
current PQL
Data support
lower PQL
Data support
lower PQL
Data may
support lower
PQL
Data support
lower PQL
No data <
current PQL
No data < PQL;
passing rates
high in vicinity
of current PQL
Data indicate no
change to
current PQL
No data <
current PQL
Data support
lower PQL
Data support
lower PQL
Data support
lower PQL
Data may
support lower
PQL
Current
Evaluation of
Six-Year 2
(ERA 1999-
2004) Data
No data <
current PQL
Data indicate
no change to
current PQL
Data support
lower PQL
No data <
current PQL;
passing rates
generally high
in vicinity of
current PQL
Data may
support lower
PQL
Data support
lower PQL
No data <
current PQL
Data support
lower PQL
No data <
current PQL
No data <
current PQL
No data <
current PQL;
passing rates
variable in
vicinity of
current PQL
No data <
current PQL;
passing rates
variable in
vicinity of
current PQL
Data support
lower PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
Overall Qualitative
Recommendation
No change to current PQL
No change to current PQL
Reduction of current PQL
supported
Reduction of current PQL
supported
Slight reduction of current PQL
may be supported
Reduction of current PQL
supported
No change to current PQL
Reduction of current PQL
supported
No change to current PQL
No change to current PQL
Reduction of current PQL may
be supported
Reduction of current PQL may
be supported
Reduction of current PQL
supported
Reduction of current PQL may
be supported
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Analyte
Pentachlorophenol
PCBs as DCBP
Tetrachloroethylene
Thallium
Toxaphene
1 , 1 ,2-Trichloroethane
Trichloroethylene
Vinyl chloride
Current
PQL
(mg/L)
0.001
0.0005
0.005
0.002
0.003
0.005
0.005
0.002
New or Updated
Methods?
Yes - may improve
analytical
performance in
vicinity of current
PQL. New method
515.4 has capability
of a lower MDL.
No
No
No
No
No
No
No
PQL Assessment Results
Current
Evaluation of
Six-Year 1
Data
Data indicate no
change to
current PQL
Data indicate no
change to
current PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
Data may
support lower
PQL
Data support
lower PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
Current
Evaluation of
Six-Year 2
(ERA 1999-
2004) Data
No data <
current PQL
No data <
current PQL
Data support
lower PQL
No data <
current PQL
No data <
current PQL;
passing rates
variable in
vicinity of
current PQL
Data support
lower PQL
Data support
lower PQL
Data may
support lower
PQL
Overall Qualitative
Recommendation
No change to current PQL
No change to current PQL
Reduction of current PQL
supported
No change to current PQL
Reduction of current PQL may
be supported
Reduction of current PQL
supported
Reduction of current PQL
supported
Reduction of current PQL may
be supported
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Exhibit 138: Second Six-Year Review Analytical Feasibility Assessment Summary
Analytes with MCL Greater than the Current PQL and Thus it is Technically Feasible to
Reduce the MCL - 41 Analytes
Analyte
Arsenic
Atrazine
Barium
Beryllium
Cadmium
Carbofuran
Chromium
Copper
Current
PQL
(mg/L)
0.003
0.001
0.15
0.001
0.002
0.007
0.01
0.05
New or Updated
Methods?
Yes - not expected
to improve
analytical
performance in
vicinity of current
PQL
Yes - Effect on
performance
unknown. DLfrom
new method
needed to assess
effect on analytical
performance in
vicinity of current
PQL
Yes - not expected
to improve
analytical
performance in
vicinity of current
PQL
Yes - not expected
to improve
analytical
performance in
vicinity of current
PQL
Yes - not expected
to improve
analytical
performance in
vicinity of current
PQL
Yes - may improve
analytical
performance in
vicinity of current
PQL. New method
531.2 has lower
MDL
Yes - not expected
to improve
analytical
performance in
vicinity of current
PQL
Yes - not expected
to improve
analytical
performance in
vicinity of current
PQL
PQL Assessment Results
Current
Evaluation of
Six-Year 1
Data
Data indicate no
change to
current PQL
Data may
support lower
PQL
Data support
slightly lower
PQL
Data indicate no
change to
current PQL
No data <
current PQL
Data support
lower PQL
No data <
current PQL
Data indicate no
change to
current PQL
Current
Evaluation of
Six-Year 2
(ERA 1999-
2004) Data
No data <
current PQL
current PQL;
passing rates
variable in
vicinity of
current PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
No data <
current PQL
No data <
current PQL
current PQL;
passing rates
variable in
vicinity of
current PQL
No data <
current PQL
No data <
current PQL
Overall Qualitative
Recommendation
No change to current PQL
Reduction of current PQL may
be supported
Slight reduction of current PQL
supported
No change to current PQL
No change to current PQL
Reduction of current PQL may
be supported
No change to current PQL
No change to current PQL
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Analyte
Cyanide (as free cyanide)
Dalapon
1 ,2-Dichlorobenzene
(o-Dichlorobenzene)
1 ,4-Dichlorobenzene
(p-Dichlorobenzene)
1,1-Dichloroethylene
c/s-1 ,2-dichloroethylene
frans-1,2-
Dichloroethylene
2,4-Dichlorophenoxy-
acetic acid (2,4-D)
Di(2-ethylhexyl) adipate
(DEHA)
Dinoseb
Current
PQL
(mg/L)
0.1
0.01
0.005
0.005
0.005
0.005
0.005
0.005
0.006
0.002
New or Updated
Methods?
Yes - effect on
performance
unknown. DLsfrom
new method(s)
needed to assess
effect on analytical
performance in
vicinity of current
PQL
Yes- may improve
analytical
performance in
vicinity of current
PQL. MDLfrom
new methods 515.4
and 552.3 are lower
than previous MDLs
No
No
No
No
No
Yes - may improve
analytical
performance in
vicinity of current
PQL. New method
515.4 has lower
MDL
No
Yes - may improve
analytical
performance in
vicinity of current
PQL. New method
515.4 has lower
MDL.
PQL Assessment Results
Current
Evaluation of
Six-Year 1
Data
No data <
current PQL
Cannot
determine
passing rates
for data <
current PQL
No data <
current PQL
Data support
lower PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
Data indicate no
change to
current PQL
Cannot
determine
passing rate for
data < current
PQL
No data <
current PQL
Current
Evaluation of
Six-Year 2
(ERA 1999-
2004) Data
No data <
current PQL
No data <
current PQL
No data <
current PQL
Data support
lower PQL
Data support
lower PQL
Data support
lower PQL
Data may
support lower
PQL; passing
rates generally
high in vicinity
of current PQL
No data <
current PQL
No data <
current PQL
No data <
current PQL
Overall Qualitative
Recommendation
No change to current PQL
No change to current PQL
No change to current PQL
Reduction of current PQL
supported
Reduction of current PQL
supported
Reduction of current PQL
supported
Reduction of current PQL may
be supported
No change to current PQL
No change to current PQL
No change to current PQL
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Analyte
Diquat
Endothall
Endrin
Ethylbenzene
Fluoride
Glyphosate
Hexachlorocyclopenta-
diene
Lead
Mercury
Methoxychlor
Monochlorobenzene
(Chlorobenzene)
Current
PQL
(mg/L)
0.004
0.09
0.0001
0.005
0.5
0.06
0.001
0.005
0.0005
0.01
0.005
New or Updated
Methods?
No
No
No
No
Yes- may improve
analytical
performance in
vicinity of current
PQL. MDLfrom
new method 300.1
is slightly lower
than MDLfrom
300.0.
No
No
Yes - not expected
to improve
analytical
performance in
vicinity of current
PQL
Yes- may improve
analytical
performance in
vicinity of current
PQL. MDLfrom
new method 245.7
is significantly lower
than previous MDLs
No
No
PQL Assessment Results
Current
Evaluation of
Six-Year 1
Data
No data <
current PQL
Cannot
determine
passing rate for
data < current
PQL
No data <
current PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
Insufficient data
< current PQL
No data <
current PQL
Data may
support lower
PQL
Data indicate no
change to
current PQL
Data indicate no
change to
current PQL
Data support
lower PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
Current
Evaluation of
Six-Year 2
(ERA 1999-
2004) Data
No data <
current PQL
No data <
current PQL
No data <
current PQL
Data support
lower PQL
No data <
current PQL
No data <
current PQL
No data <
current PQL;
passing rates
variable in
vicinity of
current PQL
No data <
current PQL
No data <
current PQL
No data <
current PQL;
passing rates
variable in
vicinity of
current PQL
Data support
lower PQL
Overall Qualitative
Recommendation
No change to current PQL
No change to current PQL
No change to current PQL
Reduction of current PQL
supported
No change to current PQL
No change to current PQL
Reduction of current PQL may
be supported
No change to current PQL
No change to current PQL
Reduction of current PQL may
be supported
Slight reduction of current PQL
supported
Page 162
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EPA815-B-09-003
October 2009
Analyte
Nitrate (as N)
Nitrite (as N)
Oxamyl (Vydate)
Picloram
Selenium
Simazine
Styrene
Toluene
Current
PQL
(mg/L)
0.4
0.4
0.02
0.001
0.01
0.0007
0.005
0.005
New or Updated
Methods?
Yes - not expected
to improve
analytical
performance in
vicinity of current
PQL. MDLfrom
new method 300.1
is higher than that
from 300.0.
Yes - may improve
analytical
performance in
vicinity of current
PQL. MDLfrom
new method 300.1
is lower than
previous MDLs
Yes - may improve
analytical
performance in
vicinity of current
PQL. MDLfrom
new method 531.2
is lower than
previous MDLs
Yes - may improve
analytical
performance in
vicinity of current
PQL. New method
515.4 has lower
MDL
Yes - not expected
to improve
analytical
performance in
vicinity of current
PQL
No
No
No
PQL Assessment Results
Current
Evaluation of
Six-Year 1
Data
No data <
current PQL
Data support
lower PQL
Data indicate no
change to
current PQL
No data <
current PQL
Insufficient data
< current PQL
Cannot
determine
passing rate for
data < current
PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
Current
Evaluation of
Six-Year 2
(ERA 1999-
2004) Data
No data <
current PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
No data <
current PQL
No data <
current PQL
No data <
current PQL
No data <
current PQL
Data support
lower PQL
Data support
lower PQL
Overall Qualitative
Recommendation
No change to current PQL
Reduction of current PQL
supported
No change to current PQL
No change to current PQL
No change to current PQL
No change to current PQL
Reduction of current PQL
supported
Reduction of current PQL
supported
Page 163
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EPA815-B-09-003
October 2009
Analyte
2,4,5-TP (Silvex)
1 ,2,4-Trichlorobenzene
1,1,1-Trichloroethane
Xylenes (total)
Current
PQL
(mg/L)
0.005
0.005
0.005
0.005
New or Updated
Methods?
Yes - may improve
analytical
performance in
vicinity of current
PQL. New method
515.4 has capability
of a lower MDL.
No
No
No
PQL Assessment Results
Current
Evaluation of
Six-Year 1
Data
Data support
lower PQL
No data <
current PQL;
passing rates
high in vicinity
of current PQL
Data support
lower PQL
current PQL
Current
Evaluation of
Six-Year 2
(ERA 1999-
2004) Data
No data <
PQL; passing
rates variable
in vicinity of
current PQL
Data support
lower PQL
Data support
lower PQL
Data indicate
no change to
current PQL
Overall Qualitative
Recommendation
Reduction of current PQL may
be supported
Reduction of current PQL
supported
Reduction of current PQL
supported
No change to current PQL
Improved analytical performance (and hence, possible PQL reduction) may also be
supported by the approval and availability of new or revised analytical methods with lower
MDLs (note that in some analytical methods, the term DL is used instead of MDL, but these
quantities are essentially equivalent). For 15 regulated analytes, new methods have been
approved. For 12 of these analytes (bromate, carbofuran, 2,4-D, dalapon, dinoseb, fluoride,
mercury, nitrite, oxamyl, pentachlorophenol, picloram and 2,4,5-TP), the MDLs are lower (or
their range of MDLs includes values that are lower) than those from earlier-approved methods.
In two cases (atrazine and cyanide), the methods are proprietary and are not readily available;
hence, MDLs are not known, and comparison cannot be made. Lastly, in one case (nitrate), new
or revised methods do not indicate a lower MDL.
Overall, the results show that only for 20 of the 66 analytes evaluated in this report,
laboratory performance data was sufficient to qualitatively conclude that the PQL can be
lowered. For 14 analytes there were indications for a lower PQL but for the remaining 32 either
the data were inconclusive or insufficient to draw a conclusion. Furthermore, for only 3 of the
20 analytes for which PQL could be lowered, the improved analytical performance was
supported by new and improved methods approval. For others, there was either no correlation or
correlation could not be made due to insufficient data.
Page 164
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October 2009
8.0 References
NEMI. 2008. National Environmental Methods Index, available on the Internet at:
http://www.nemi.gov/apex/f?p=237:1:1342350837485455: accessed March, 2008.
USEPA. 1985a. National Primary Drinking Water Regulations; Volatile Synthetic Organic
Chemicals; Final Rule and Proposed Rule. Federal Register. Vol. 50, No. 219, p. 46880,
November 13, 1985.
USEPA. 1985b. National Primary Drinking Water Regulations; Volatile Synthetic Organic
Chemicals; Proposed Rule. Federal Register. Vol. 50, No. 219, p. 46902, November 13, 1985.
USEPA. 1987. National Primary Drinking Water Regulations - Synthetic Organic Chemicals;
Monitoring for Unregulated Contaminants; Final Rule. Federal Register. Vol. 52, No. 130,
p. 25690, July 8, 1987.
USEPA. 1988. Drinking Water Regulations; Maximum Contaminant Level Goals and National
Primary Drinking Water Regulations for Lead and Copper; Proposed Rule. Federal Register.
Vol. 53, No. 160, p. 31516, August 18, 1988.
USEPA. 1989. National Primary and Secondary Drinking Water Regulations; Synthetic Organic
Chemicals and Inorganic Chemicals; Proposed Rule. Federal Register. Vol. 55, No. 143, p.
30370, July 25, 1990.
USEPA. 1990. National Primary and Secondary Drinking Water Regulations; Proposed Rule.
Federal Register. Vol. 54, No. 97, p. 22062, May 22, 1989.
USEPA. 199la. National Primary Drinking Water Regulations - Synthetic Organic Chemicals
and Inorganic Chemicals; Monitoring for Unregulated Contaminants; National Primary
Drinking Water Regulations Implementation; National Secondary Drinking Water
Regulations; Final Rule. Federal Register. Vol. 56, No. 30, p. 3526, January 30, 1991.
USEPA. 1991b. Drinking Water; National Primary Drinking Water Regulations; Radionuclides;
Proposed Rule. Federal Register. Vol. 56, No. 138, p. 33050, July 18, 1991.
USEPA. 1992. National Primary and Secondary Drinking Water Regulations - Synthetic
Organic Chemicals and Inorganic Chemicals; National Primary Drinking Water Regulations
Implementation Federal Register. Vol. 57, No. 138, p. 31776, July 17, 1992.
USEPA. 1998. National Primary Drinking Water Regulations: Disinfectants and Disinfection
Byproducts; Final Rule. Federal Register. Vol. 63, No. 241, p. 69390, December 16, 1998.
USEPA. 1999. Analytical Methods Support Document For Arsenic In Drinking Water, EPA-
815-R-00-010, December.
USEPA. 2000. National Primary Drinking Water Regulations; Radionuclides; Final Rule.
Federal Register. Vol. 65, No. 236, p. 76708, December 7, 2000.
Page 165
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EPA - OGWDW Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
USEPA. 2002a. Guidelines Establishing Test Procedures for the Analysis of Pollutants Under
the Clean Water Act; National Primary Drinking Water Regulations; and National Secondary
Drinking Water Regulations; Methods Update; Final Rule. Federal Register. Vol. 67, p.
65220, October 23, 2002.
USEPA. 2002b. Unregulated Contaminant Monitoring Regulation: Approval of Analytical
Method for Aeromonas; National Primary and Secondary Drinking Water Regulations:
Approval of Analytical Methods for Chemical and Microbiological Contaminants; Final Rule.
Federal Register. Vol. 67, p. 65888, October 29, 2002.
USEPA. 2003a. EPA Protocol for the Review of Existing National Primary Drinking Water
Regulations, EPA-815-R-03-002, June 2003.
USEPA. 2003b. National Primary Drinking Water Standards, EPA-816-F-03-016, June 2003.
USEPA. 2003c. Analytical Feasibility Support Document for the Six-Year Review of National
Primary Drinking Water Regulations, EPA-815-R-03-003, March 2003.
USEPA. 2006. National Primary Drinking Water Regulations: Stage 2 Disinfectants and
Disinfection Byproducts Rule; Final Rule. Federal Register. Vol. 71, p. 388, January 4, 2006.
USEPA. 2007. Guidelines Establishing Test Procedures for the Analysis of Pollutants Under the
Clean Water Act; National Primary Drinking Water Regulations; and National Secondary
Drinking Water Regulations; Analysis and Sampling Procedures; Final Rule. Federal Register.
Vol. 72, p. 11200, March 12, 2007.
USEPA. 2009. Development of Estimated Quantitation Levels for the Six-Year Review of
National Primary Drinking Water Regulations. Draft; in preparation.
Weisberg, S. 1985. Applied Linear Regression, New York: John Wiley & Sons, Inc.
Page 166
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EPA815-B-09-003
October 2009
Appendix A: Listing of New and Updated Analytical Methods
Exhibit A-l lists analytical methods that have been developed or revised and approved
for the analysis of drinking water during the years 2000 - 2007. In many cases, the new methods
or revisions to existing methods are not expected to significantly improve laboratory
performance at low concentration (i.e., in the vicinity of the current PQL). Many of the revisions
relate to clarifications to technical language, solvent replacements to improve safety, or other
administrative changes/clarifications that are not expected to affect analytical performance.
Improved analytical performance (and hence, possible PQL reduction) may also be
supported by the approval and availability of new or revised analytical methods with lower
MDLs (note that in some analytical methods, the term DL is used instead of MDL, but these
quantities are essentially equivalent). For 15 regulated analytes, new methods have been
approved. For 12 of these analytes (bromate, carbofuran, 2,4-D, dalapon, dinoseb, fluoride,
mercury, nitrite, oxamyl, pentachlorophenol, picloram and 2,4,5-TP), the MDLs are lower (or
their range of MDLs includes values that are lower) than those from earlier-approved methods.
In two cases (atrazine and cyanide), the methods are proprietary and are not readily available;
hence, MDLs are not known, and comparison cannot be made. Lastly, in one case (nitrate), new
or revised methods do not indicate a lower MDL.
Exhibit A-l: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR §§141.23, 141.24, and 141.131
Revised/
New Method
Old Method
NPDWR/Contaminant(s)
Notes
Source: Guidelines Establishing Test Procedures for the Analysis of Pollutants Under the Clean Water
Act; National Primary Drinking Water Regulations; and National Secondary Drinking Water Regulations;
Methods Update; Final Rule. Federal Register, Vol. 67, No. 205, p. 65220, October 23, 2002. Initial rule
notices, including direct final rule and proposed rule published January 16, 2001 : Federal Register, Vol.
66, p. 3466 and Federal Register, Vol. 66, p. 3526, respectively.1
D2972-97C
D2972-97B
D3645-97B
D2036-98A
D2036-98B
D4327-97
D3559-96D
D3223-97
D3859-98A
D2972-93C
D2972-93B
D3645-93B
D2036-91A
D2036-91B
D4327-91
D3559-95D
D3223-91
D3859-93A
arsenic
beryllium
cyanide
fluoride, nitrate, nitrite
lead
mercury
selenium
Methods updates from 1999 Annual
Book ofASTM Standards, Vols. 1 1 .01
and 1 1 .02; revisions to 141 .23(k)(1)
inorganic analysis; per FR notice,
these do not contain substantive
changes in procedures or
instrumentation, rather, they focus on
safety factors; see §141 .23. Examples
of minor technical changes are
recommendations for the handling of
hazardous materials and safer or
better ways to conduct certain
hazardous or complicated analytical
procedures. Some of the ASTM
methods have been augmented (cont.)
Page A-l
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit A-l: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR §§141.23,141.24, and 141.131
Revised/
New Method
Old Method
NPDWR/Contaminant(s)
Notes
D3859-98B
D3859-93B
with additional tables of method
performance data." No further method-
specific explanations were provided.
3120 B
arsenic, barium, beryllium,
chromium, copper
4500-CN- C
4500-CN- G
4500-CN- E
4500-CN- F
4110B
4500-F- B,D
4500-F- C
CD
O)
C
CO
.C
o
i_
CD
Ģ2
E
CD
CO
cyanide
fluoride, nitrate, nitrite
fluoride
4500-F- E
4500-NO, - F
4500-NO-, - E
nitrate, nitrite
4500-NO-, - D
nitrate
4500-N02 - B
nitrite
Methods updates from Standard
Methods for the Examination of Water
and Wastewater, 20th Ed., 1998;
revisions to 141.23(k)(1) Inorganic
analysis; per FR notice changes are
editorial and technical clarifications;
see §141.23. More specifically, the
initial Federal Register notice (66 FR
3466) explains that: "Of the 71
Standard Methods included in today's
rule, 52 methods are unchanged from
previous versions. The remaining 19
methods contain minor editorial
changes or technical clarifications.
Some of these revisions are minor
modifications or voluntary but useful
options, such as better explanations on
conducting a specific step in the
method; recommendations for safer
handling or disposal of hazardous
reagents; and options to use
alternative procedures, reagents, or
equipment." Only the 13 methods
listed to the left apply to this Second
Six-Year Review of NPDWRs.
Source: Unregulated Contaminant Monitoring Regulation: Approval of Analytical Method for
Aeromonas; National Primary and Secondary Drinking Water Regulations: Approval of Analytical
Methods for Chemical and Microbiological Contaminants. Federal Register, Vol. 67, No. 209, p. 65888,
October 29, 2002. Proposed rule: Federal Register, Vol. 67, p. 10532, March 7, 2002.
EPA Method
515.4
none
2,4-D (as acid, salts and esters),
2,4,5-TP (Silvex), dinoseb,
pentachlorophenol, picloram and
dalapon
Available at:
http://www.epa.gov/safewater/methods
/; see §141.24. New method. Method
515.4 is a Gas Chromatography
method that was initially approved for
Unregulated Contaminant Monitoring
Regulation analyses.
Available at:
http://www.epa.gov/safewater/methods
EPA Method
531.2
none
carbofuran and oxamyl
/; see §141.24. New method. This
method improves sample preservation
procedures that are required under
EPA Method 531.1 and SM 6610, and
updates the method (cont.)
Page A-2
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit A-l: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR §§141.23, 141.24, and 141.131
Revised/
New Method
Syngenta
AG-625
Kelada 01
QuikChem
10-204-00-
1-X
Old Method
none
none
none
NPDWR/Contaminant(s)
atrazine
cyanide
Notes
performance tables using data
generated with more up to date
equipment. Accuracy, precision and
detection limit data generated using
this method is superior to that
generated with either of the currently
approved methods.
"Atrazine in Drinking Water by
Immunoassay", February 2001
available from Syngenta Crop
Protection, Inc., 410 Swing Road, Post
Office Box 18300, Greensboro, NC
27419, Phone number (336) 632-
6000; see §141.24. New method.
This is an industry-developed method
that meets EPA's criteria for method
performance, and is "a satisfactory
compliance method for atrazine in
drinking water."
"Kelada Automated Test Methods for
Total Cyanide, Acid Dissociable
Cyanide, And Thiocyanate", Revision
1 .2, August 2001 , EPA # 821-B-01-
009 for cyanide is available from the
National Technical Information Service
(NTIS), PB 2001-108275, 5285 Port
Royal Road, Springfield, VA22161;
800-553-6847; see § 141.23. New
method. Validated in both single and
multi-laboratory validation studies,
Kelada 01 is "a satisfactory compliance
method for total cyanide in drinking
water."
"Digestion and distillation of total
cyanide in drinking and wastewaters
using MICRO DIST and determination
of cyanide by flow injection analysis",
Revision 2.1 , November 30, 2000 for
cyanide is available from Lachat
Instruments, 6645 W. Mill Rd.,
Milwaukee, Wl 53218; 414-358-4200;
see §141 .23. New method.
Validated in both single and multi-
laboratory validation studies,
QuikChem 1 0-204-00-1 -X is "a
satisfactory compliance method for
total cyanides in drinking water."
Page A-3
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit A-l: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR §§141.23,141.24, and 141.131
Revised/
New Method
Old Method
NPDWR/Contaminant(s)
Notes
Source: National Primary Drinking Water Regulations: Stage 2 Disinfectants and Disinfection
Byproducts Rule; Final Rule. Federal Register, Vol. 71, No. 2, p. 388, January 4, 2006. Proposed Rule:
Federal Register, Vol. 68, No. 159, p. 49548, August 18, 2003.
EPA Method
317.0 rev 2.0
300.1
bromate and chlorite
EPA Method 317.0 Revision 2 uses the
EPA Method 300.1 technology, but it
adds a postcolumn reactor that
provides a more sensitive and specific
analysis for bromate than is obtained
using EPA Method 300.1.
Several advantages of this method:
(1) Very few ions react with ODA to
form compounds that are detected by
the UV/Vis detector. This makes the
method less susceptible to
interferences for bromate.
(2) The UV/Vis detector is very
sensitive to the chromophore, so lower
concentrations of bromate can be
detected and quantitated. (Bromate
concentrations can be reliably
quantitated as low as 1 ug/L using this
detector versus 5 ug/L for EPA Method
300.1.)
(3) Since the front part of the analysis
is the same as EPA Method 300.1,
bromate, chlorite, and bromide can be
determined in the same analysis.
EPA Method
321.8
bromate
The advantage of this method is that it
is very specific and sensitive to
bromate. The single laboratory
detection limit presented in the method
is 0.3 ug/L.
EPA Method
326.0
bromate and chlorite
Method provides higher quality
bromate data than the currently
approved EPA Method 300.1 when
bromate concentrations are below 10
ug/ L. EPA anticipates the number of
laboratories using this method will
increase as utilities become aware of
the method's sensitivity and begin to
request it be used for their samples.
EPA Method
327.0 rev 1.1
chlorite (daily monitoring only)
EPA Method 327.0 offers advantages
over the currently approved methods in
that it is not subject to positive
interferences from other chlorine (cont.)
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit A-l: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR §§141.23,141.24, and 141.131
Revised/
New Method
Old Method
NPDWR/Contaminant(s)
Notes
species and it is easier to use. See §
141.131.
SM 4500-
CIO2 E and
E-00
chlorite (daily monitoring only)
Standard Methods Section 4500-CIO2
contains the methods for determining
chlorine dioxide residuals and chlorite
and it includes method 4500-CIO2E.
On-Line Version of Standard Methods
[were]... cited in addition to the 19th
editions in order to allow flexibility for
the water systems performing the
analyses.
ASTMD
6581-00
bromate and chlorite
This method uses the same
procedures as EPA Method 300.1 (the
method promulgated in the Stage 1
DBPR) and thus is considered
equivalent to the approved method.
The ASTM method includes
interlaboratory study data that were not
available when EPA Method 300.1 was
published. The study data demonstrate
good precision and low bias for all
analytes.
Source: Guidelines Establishing Test Procedures for the Analysis of Pollutants Under the Clean Water
Act; National Primary Drinking Water Regulations; and National Secondary Drinking Water Regulations;
Analysis and Sampling Procedures; Final Rule. Federal Register, Vol. 72, No. 47, p. 11200, March 12,
2007. Proposed rules: Federal Register, Vol. 68, p. 49548, August 18, 2003 and Federal Register, Vol.
69, p. 18166, April 6, 2004.
OIA-1677,
DW
none for
drinking
water
cyanide
EPA-821-R-99-013, August 1999
Method OIA-1677, DW "Available
Cyanide by Flow Injection, Ligand
Exchange, and Amperometry,"
January 2004 is technically equivalent
to Method OIA-1677, which is
currently approved for determination of
available cyanide in the NPDES
program (64 FR 73414; December 30,
1999). Method OIA-1677, DWonly
differs from OIA- 1677 in having (a)
updated contact information, and (b)
less method modification flexibility
(references to performance-based
modifications have been removed).
Therefore the validation data on OIA-
1677 is applicable to OIA- 1677, DW.
See §141.23.
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit A-l: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR §§141.23, 141.24, and 141.131
Revised/
New Method
ASTM
D6888-04
D1 179-99(6)
D1688-02(A)
D1688-02(B)
D2972-03(B)
D2972-03(C)
D3223-02
D3559-03(D)
D3645-03(B)
D3697-02
D3859-03(A)
D3859-03(B)
D3867-99(B)
D4327-03
D5317-98
(2003)
D6508, Rev.
2
Old Method
none
01179-93(6)
D1688-95(A)
01688-95(6)
02972-97(6)
02972-97(0)
03223-97
03559-96(0)
03645-97(6)
03697-92
D3859-98(A)
03859-98(6)
03867-90(6)
04327-97
05317-93
none
NPDWR/Contaminant(s)
fluoride
copper
arsenic
mercury
lead
beryllium
antimony
selenium
nitrate, nitrite
fluoride, nitrate, nitrite
2,4-0, 2,4,5-TP,
pentachlorophenol, picloram
fluoride, nitrate, nitrite
Notes
ASTM Method 06888-04 uses a
similar technology to Method OIA-
1677. ASTM 06888-03 was proposed
with OIA-1677, but later refined and
proposed as ASTM 06888-04 in 70 FR
7909, February 16, 2005. See §
141.23.
ASTM Method updates "incorporate
minor technical and/or editorial
revisions that improve the methods."
See §141 .23.
ASTM Method updates "incorporate
minor technical and/or editorial
revisions that improve the methods."
See §141 .24.
A new method that employs capillary
ion electrophoresis to determine
common anions in wastewater and
drinking water. "Test Method for
Determination of Dissolved Inorganic
Anions in Aqueous Matrices Using
Capillary Ion Electrophoresis and
Chromate Electrolyte" (Method 06508,
Rev. 2) appears to provide an
acceptable technological alternative to
ion chromatography and wet chemical
methods in terms of method
performance and is equivalent to (cont.)
Page A-6
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit A-l: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR §§141.23, 141.24, and 141.131
Revised/
New Method
3111 B-99
3112B-99
31 13 B-99
3114B-97
31 20 B-99
4110B-00
4500-CN E-
99
4500-CN F
4500-CN G-
99
4500-F-B-97
4500-F-C-97
4500-F-D-97
4500-N02 B-
00
4500-NC-3-E-
00
4500-NO3_F-
00
EPA Method
245.7 rev 2.0
EPA Method
552.3 rev 1 .0
Old Method
3111 B[19th]
31 12 B [19th]
31 13 B [19th]
31 14 B [19th]
31 20 B [20th]
41 10 B [20th]
4500-CN E
[20th]
4500-CN F
[20th]
4500-CN G
[20th]
4500-F-B
[20th]
4500-F-C
[20th]
4500-F-D
[20th]
4500-N02 B
[20th]
4500-NO3_ E
[20th]
4500-NO3_F
[20th]
245.7
revision 1 .0
New Method
NPDWR/Contaminant(s)
copper
mercury
antimony, arsenic, barium,
beryllium, cadmium, chromium,
copper, lead, selenium
arsenic, selenium
arsenic, barium, beryllium,
chromium, copper
fluoride, nitrate, nitrite
cyanide
fluoride
nitrite
nitrate, nitrite
mercury
dalapon
Notes
other approved methods in the working
range.
Standard Methods updates include:
"...a number [with]... no changes from
previously approved version, some
incorporate minor technical and
editorial revisions to improve user-
friendliness, update references, and
correct errors." ." See §141 .23.
Reagent and instrumentation changes;
MDL is significantly lower than those
from other methods.
MDL range is lower than MDLs from
most other methods.
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit A-l: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR §§141.23, 141.24, and 141.131
Revised/
New Method
EPA Method
300.1
Old Method
none
NPDWR/Contaminant(s)
fluoride, nitrate, nitrite
Notes
EPA Method 300.1 is extended to use
for these NPDWRs, to provide greater
flexibility to laboratories and allows
them to reduce analytical costs.
1. A proposed and a direct final rule (DFR) for these methods were published simultaneously on January
16, 2001. This was done to ensure that public input requirements were met, and if no public comments
were received on the DFR, then a second revised final rule would not have been needed. The details of
the rule were contained in the DFR (66 FR 3466), and the required public comment request and
explanation of the combined proposal and DFR publication was provided in the proposed rule (66 FR
3526).
Page A-8
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Appendix B: Radionuclide Regressions
Radionuclides are a unique group of substances, as their measurement requires a unique
analytical technology compared to other analytes. MDLs and PQLs for radionuclides in drinking
water are affected by three major factors:
Type of detector;
Volume of sample available;
Duration of analysis
Thus, for the radionuclides, limitations of laboratory performance at low concentrations
is generally not an issue, as MDLs and PQLs can be lowered, if necessary, by increasing sample
volume and/or radiological analysis duration. The radionuclides for which PT data were
available from ERA (2002-2006) are included in this report for completeness; however no
conclusions regarding PQL assessment are made (note that Barium-133, Cobalt-60 and Zinc-65
do not have promulgated PQLs per 58 FR, 33050, July 18, 1991 and 65 FR 76752, December 7,
2000). Exhibit B-l summarizes the regulated radionuclides, along with their current PQL, how
the PQL was determined, their MCLG, MCL, and the current acceptance criteria for PT.
Acceptance criteria for radionuclides are based on both the average of three analyses and the
range of values obtained from three analyses (n = the assigned value). Exhibit B-2 summarizes
the availability of PE and PT data and whether data are available at or below the PQL for each
radionuclide.
Exhibit B-l: U.S. EPA National Primary Drinking Water Standards and Related
Information - Radionuclides
Analyte
Gross Alpha
Radium-226
Radium-228
Uranium
Beta particle and
photo emitters
Regulatory
Detection
Limit (pCi/L)1
3
1
1
N/A
PQL
(pCi/L)
15
5
5
5
How PQL
Determined?
PE data
PE data
PE data
PE data
MCLG
Zero
Zero
Zero
Zero
See individual constituents listed below
MCL
15pCi/L
5 pCi/L (Ra-
226 and Ra-
228)
5 pCi/L (Ra-
226 and Ra-
228)
30 ug/L
4 millirem/
year (total)
Acceptance
Criteria (pCi/L); j^ =
assigned value2
Average - 3-20
pCi/L: ^ + 8.66; >20-
<75 pCi/L: ^ + 0.433^1
Range - 3-20 pCi/L:
21.8; >20-<75 pCi/L:
1.09^
Average- 1-20
pCi/L:n+ 0.260^
Range- 1-20pCi/L:
0.654^
Average- 1-20
pCi/L' |^+0 433|^
Range- 1-20pCi/L:
1.09^
Average - 2-35
pCi/L: n + 5.20; >35-
<70 pCi/L: n + 0.173n
Range - 2-35 pCi/L:
13.1; >35-<70 pCi/L:
0.436^
See below
Page B-l
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Analyte
Gross Beta
Barium-133
Cesium-134
Cesium-137
Cobalt-60
lodine-131
Strontium-89
Strontium-90
Tritium
Regulatory
Detection
Limit (pCi/L)1
4
N/A
10
N/A
N/A
1
10
2
1,000
PQL
(pCi/L)
30
N/A
10
10
N/A
20
5
5
1,200
How PQL
Determined?
PE data
PE data
PE data
PE data
PE data
PE data
PE data
PE data
PE data
MCLG
Zero
Zero
Zero
Zero
Zero
Zero
Zero
Zero
Zero
MCL
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Acceptance
Criteria (pCi/L); n =
assigned value2
Average - 4-50
pCi/L: j^ + 8.66; >50-
<65 pCi/L: n+17.3
Range - 4-50 pCi/L:
21.8; >50-<65 pCi/L:
43.6
Average - 9-50
pCi/L: n + 8.66; >50-
<110pCi/L:
H + 0.173n
Range - 9-50 pCi/L:
21.8; >50-<110
pCi/L: 0.436^
Average -10-96
pCi/L: 1^+8.66;
Range- 10-96 pCi/L:
21.8
Average -20-1 00
pCi/L: n + 8.66;
>100-<240pCi/L:
H + 0.0866^
Range -20-1 00
pCi/L:21.8; >100-
<240pCi/L: 0.21 8n
Average- 10-100
pCi/L: n + 8.66;
>100-<120pCi/L:
l^ + 0.0866|^
Range- 10-100
pCi/L:21.8; >100-
<120pCi/L: 0.218n
Average - 1-15
pCi/L: ną3.46; >15-
<30 pCi/L: n + 5.20n
Range- 1-215pCi/L:
8.72; >15-<30pCi/L:
13.1
Average - 1 0-70
pCi/L: 1^+8.66;
Range- 10-70 pCi/L:
21.8
Average - 2-45
pCi/L: ną8.66;
Range - 2-45 pCi/L:
21.8
Average - 1,000-
4,000 pCi/L: n +
294|V-0933; >4,000-
<32,000 pCi/L:
H + 0.173n
Range- 1,000-
4,000 pCi/L:
74V°-0933; >4,000-
<32,000 pCi/L:
0.436^
Page B-2
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Analyte
Zinc-65
Regulatory
Detection
Limit (pCi/L)1
N/A
PQL
(pCi/L)
N/A
How PQL
Determined?
PE data
MCLG
Zero
MCL
N/A
Acceptance
Criteria (pCi/L); n =
assigned value2
Average - 30-50
pCi/L: n + 8.66; >50-
<360 pCi/L:
H + 0.173n
Range - 30-50 pCi/L:
21.8;>50-<360
pCi/L: 0.436^
1 Regulatory Detection Limits for radionuclides can be found at FR 65 76708, December 7, 2000.
Corresponding PQLs can be found at: 58 FR, 33050, July 18, 1991. Note that the PQL for Strontium-89
from 1991 is less than the regulatory DL from 2000.
2 Acceptance criteria are available at: http://vwvw.nelac-institute.org and are subject to change over time.
Exhibit B-2: Availability of Six-Year 1 PE Data and Six-Year 2 PE/PT Data for
Radionuclides
Analyte
Gross Alpha
Radium-226
Radium-228
Uranium
Beta particle and photo emitters
Gross Beta
Barium-133
Cesium-134
Cesium-137
Cobalt-60
lodine-131
Strontium-89
Strontium-90
Tritium
Zinc-65
In Six-Year 1 Data?1
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
Not available
In Six-year 2 ERA Data
2002-2006?
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes, some data < PQL
Yes; no PQL
Yes, no data < PQL
Yes, no data < PQL
Yes; no PQL
Yes, some data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes, no data < PQL
Yes; no PQL
1 Radionuclides were not included in the Six-Year 1 Review; therefore, no data are available.
Page B-3
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Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit B-3: Evaluation of ERA PT Data - Gross Alpha
100
O)
_c
'in
in
ra
0.
in
01
c
S
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0
0
Current PQL
= 15 pCi/L
10
20
30 40
True Value (pCi/L)
50
75%
60
70
PQL
ERA Data
-75% Passing Rate
Page B-4
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit B-4: Evaluation of ERA PT Data - Radium-226
100
O)
_c
'in
in
ra
0.
in
01
c
S
2
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0
0
75%
Current PQL
= 5 pCi/L
10
15
20
True Value (pCi/L)
PQL
ERA Data
-75% Passing Rate
Page B-5
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit B-5: Evaluation of ERA PT Data - Radium-228
100
O)
_c
'in
in
ra
0.
in
01
c
S
2
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0
0
75%
Current PQL
= 5 pCi/L
10
15
20
True Value (pCi/L)
PQL
ERA Data
-75% Passing Rate
Page B-6
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit B-6: Evaluation of ERA PT Data - Uranium
100
O)
_c
'in
in
ra
0.
in
01
c
S
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0
0
Current PQL
= 5 pCi/L
10
20
30 40
True Value (pCi/L)
50
75%
60
70
PQL
ERA Data
-75% Passing Rate
Page B-7
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit B-7: Evaluation of ERA PT Data - Gross Beta
100
O)
_c
'in
in
ra
0.
in
01
c
S
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0
0
10
20
Current PQL
= 30 pCi/L
30 40
True Value (pCi/L)
50
75%
60
70
PQL
ERA Data
-75% Passing Rate
Page B-8
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit B-8: Evaluation of ERA PT Data - Barium-133
100
O)
_c
'in
in
ra
0.
in
01
c
S
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0
75%
0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0 110.0
True Value (pCi/L)
ERA Data
-75% Passing Rate
Page B-9
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit B-9: Evaluation of ERA PT Data - Cobalt-60
100
O)
_c
'in
in
ra
0.
in
01
c
S
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0
0.0
75%
20.0
40.0 60.0 80.0
True Value (pCi/L)
100.0
120.0
ERA Data
-75% Passing Rate
PageB-10
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit B-10: Evaluation of ERA PT Data - Cesium-134
100
O)
_c
'in
in
ra
0.
in
01
c
S
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
75%
Current PQL
= 10 pCi/L
10 20 30 40 50 60 70
True Value (pCi/L)
90
100
PQL
ERA Data
-75% Passing Rate
PQL
PageB-11
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review EPA 815-B-09-003
October 2009
Exhibit B-ll: Evaluation of ERA PT Data - Cesium-137
100
O)
_c
'in
in
ra
0.
in
01
c
S
o
.a
ra
90 -
70 -
60 -
50 -
40 -
30 -
20 -
10 -
0
75%
Current PQL
= 10 pCi/L
0 25 50 75 100 125 150
True Value (pCi/L)
175
200
225
250
PQL
ERA Data
-75% Passing Rate
PageB-12
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
90 -
80 -
70 -
O)
c
"> fin -
in uu
ro
Q.
1 50-
fi
ro
5 40-
S? 30-
20 -
10 -
Exhibit B-12: Evaluation of ERA PT Data - Iodine-131
"~ ! _
75%
Current PQL
= 20 pCi/L
] 5 10 15 20 25 3
True Value (pCi/L)
0
PageB-13
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
Exhibit B-13: Evaluation of ERA PT Data - Strontium-89
o
&
ra
100
90 -
70 -
60 -
in
in
ro
a.
8 50-1
40 -
30 -
20 -
10 -
0
0
Current PQL
= 5 pCi/L
10
20 30
True Value (pCi/L)
40
75%
50
60
PQL
ERA Data
-75% Passing Rate
PageB-14
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
90 -
80 -
70 -
O)
c
"> fin -
in uu
ro
Q.
1 50-
fi
ro
5 40-
S? 30-
20 -
10 -
Exhibit B-14: Evaluation of ERA PT Data - Strontium-90
75%
Current PQL
= 5 pCi/L
] 5 10 15 20 25 30 35 4
True Value (pCi/L)
0
PageB-15
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EPA - OGWDW
Analytical Feasibility Support Document for the Second Six-Year Review
EPA815-B-09-003
October 2009
100 -
90 -
80 -
70 -
O)
c
"> fin -
in uu
ro
Q.
1 50-
fi
ro
5 40-
.Q
S? 30-
20 -
10 -
o -
Exhibit B-15: Evaluation of ERA PT Data - Tritium
4
75%
Current PQL
= 1,200pCi/L
] 5,000 10,000 15,000 20,000 25,000 30,000 35,000
True Value (pCi/L)
PageB-16
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Analytical Feasibility Support Document for the Second Six-Year Review
EPA 81 5-B-09-003
October 2009
100 -
90 -
80 -
70 -
O)
s 6°-
ro
a.
1 5°-
'C
(0
I 4°
S? 30-
20 -
10 -
0 -
0
Exhibit B-16: Evaluation of ERA PT Data - Zinc-65
r2_i^-r - ' '
75%
0 50.0 100.0 150.0 200.0 250.0 300.0
True Value (pCi/L)
PageB-17
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