## Analytical Feasibility Support Document for the Second Six

- Year Review of Existing National Primary Drinking Water Regulations

### Office of Water (4607M)
EPA 815-B-09-003
October 2009 www.epa.gov/safewaterEPA

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### 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.EPA

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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 treatmen t 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 th e 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 fi rst 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 presente d 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 an d 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 resul t 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 pro gram 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 sa mples 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 t he radionuclide PT data are evaluated in this report (see Appe ndix B) for completeness, no conclusions are drawn regarding changes to PQLs.

The r esults 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 ofEPA

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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 t ot al of 66 anal ytes . 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

t o 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, cis -1,2-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, trans -1,2-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
i nsufficient to reach a conclusion for 24 analytes : arsenic, beryllium, cadmium,
ch romium, 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 Performa nce 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 ne w methods

. T he existence of new methods with lower detection limits may not directly translate to improvedEPA

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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 t o 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, nitrit e, oxamyl, pentachlorophenol, picloram and 2,4,5- TP), the MDLs are lo wer (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.EPA

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### Abbreviations and Acronyms

μ g/L Microgram s per liter mg/L Milligram s per liter

Der. Derivatization
ACVT Automated Cold Vapor Technique
AES Atomic Emission Spectrometr y APG Analytical Products Group, Inc.
ASTM American Society for Testing and Materials
CASRN Chemical Abstracts Service Registry Number
CBI Confidential Business Information
CCGC Capillary Column Gas Chromatography
CUV Coupled Ultraviolet
CVAAS Cold Vapor Atomic Absorption Spectrometry
CVAFS Cold Vapor Atomic Fluorescence Spectrometry
CFR Code of Federal Regulations 2,4-D 2,4- Dichlorphenoxyacetic acid
DAI Direct Aqueous Injection
DBCP 1,2-Dibromo-3-chloropropane
DCBP Decachlorobiphenyl
DEHA Di(2

- ethylhexyl)adipate

DEHP Di(2

- ethylhexyl)phthalate

DL Detection Limit
ECD Elect ron Capture Detection
ECGC Electron Capture Gas Chromatography

EDB Ethylene Dibromide (1,2-dibromoethane)
ELCD Electrolytic Conductivity Detector
EPA United States Environmental Protection Agency
ERA Environmental Resource Associates (name change d to ERA - A Waters Company, effective July 10, 2009)

FD Fluorescence Detection

FR Federal Register
GC Gas Chromatography
GFAA Graphite Furnace Atomic Absorption
HPLC High P erformance Liquid Chromatography
IC Ion Chromatography
ICP Inductively Coupled Plasma
ICR Information Collection Request

I- EE Ion

- Exchange Extraction

I- ELSE Ion -Exchange Liquid/Solid Extraction

IMDL Interlaboratory Method Detection Limit

LLE Liquid/Liquid Extraction

LLED Liquid/Liquid Extraction and Derivatizatio n LLMED Liquid/Liquid Microextraction and Derivatization
L/S Liquid/Solid
LSE Liquid/Solid ExtractionEPA

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### MCL Maximum Contaminant L evel
MCLG Maximum Contaminant Level Goal

MDL Method Detection Limit

ME Microextraction

ML Minimum Level

MLPD Mul ti

- Laboratory Performance Data

MRL Minimum Reporting L evel
MS Mass S pectrometry NDWAC National Drinking Water Advisory Council
NELAC National Environmental Laboratory Accreditation Conference

NERL National Exposure Research Laboratory

N- PD Nitrog en -Phosphorus Detector

NPDWR National Primary Drinking Water Regulation
OLS Ordinary Least Squares
PCB Polychlorinatedbiphenyl
PDAUVD Photodiode Array Ultraviolet Detector

PE Performance Evaluation

PID Photoionization Detector PQL Practical Qua ntitation Level

PT Pro ficiency T esting QA Quality A ssurance QC Quality C ontrol

RDL Regulatory Detection Limit
SD Standard Deviation(s)
SDWA Safe Drinking Water Act

TNI The NELAC Institute

TT Treatment Technique 2,4,5- TP 2-(2,4,5- Trichlorop henoxy)propionic acid
U.S.C. United States Code
USEPA United States Environmental Protection Agency
UVD Ultraviolet Detection
VOC Volatile Organic CompoundEPA

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### Executive Summary

...................................................................................................................... ii

Abbreviations and Acronyms ...................................................................................................... v

1.0 Introdu ction ....................................................................................................................... 1

2.0 Background ....................................................................................................................... 2

3.1 B IAS

................................................................................................ ............................................................ 9 2.3 O PERATIONAL D ETAILS OF THE PE/ P ROGRAMS

..................................................................................... 6 PT
2.4 E FFORTS M ADE TO O BTAIN D ATA

......................................................................................................... 8 PT



### 3.0 Representativeness of Available Data ....................................................................... 8 PT 2.1 R ELATIONSHIP B ETWEEN SDWA R EQUIREMENTS AND A NALYTICAL M ETHODS

....................................... 2
2.2 PQL D ETERMINATION M ETHODS FOR THE SDWA C ONTAMINANTS

........................................................... 3

3.2 P RECISION

................................................................................................ ................................................... 9
3.3 T HE R EGRESSION M ODEL

.......................................................................................................................... 10



### 4.0 Identification of Regulated Analytes for PQ L Assessment ......................................... 11

5.0 Second Six

- Year Review PQL Assessment Methodology ............................................ 15

5.1 D ATA A VAILABLE FOR PQL A SSESSMENT

................................................................................................ 15
5.2 C ALCULATING N ATIONAL P ASSING R ATES

............................................................................................... 19
5.3 R EGRESSION P LOTS

................................................................................................ ................................... 20



### 6.0 Results of PQL Assessment ............................................................................................ 21

6.1 A NALYTES WITH M AXIMUM C ONTAMINANT L EVEL (MCL) E QUAL TO THE C URRENT PQL AND T HUS 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 

### TABLE OF CONTENTS

Acknowledgments .......................................................................................................................... iEPA

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................................................................................................ ........................................... 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 Assessmen t 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 1,2

- Dibromo -3- chloropropane

.......................................................................................................... 46 Heptachlor

......................................................................................................... ................................................ 47 Results of the Methods Comparison

.......................................................................................................................... 47 Results of the PQL Analysis

................................................................................................ ...................................... 47 Conclusion for Hep tachlor

................................................................................................ ......................................... 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 t he 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

............................................................................................................................... 62EPA

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- ethylhexyl)phthalate (DEHP)

.................................................................................................................... 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 A NALYTES WITH M AX IMUM C ONTAMINANT L EVEL (MCL) G REATER T HAN THE C URRENT PQL AND
T HUS IT IS T ECHNICALLY F EASIBLE TO R EDUCE 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 Met hods Comparison

.......................................................................................................................... 75 Results of the PQL Analysis

................................................................................................ ...................................... 75 Conclusion for 1,4

- Dichlorobenzene

......................................................................................................................... 76
cis

- 1,2

- 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

Resul ts 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

Re sults of the Methods Comparison

.......................................................................................................................... 83 Results of the PQL Analysis

................................................................................................ ...................................... 83
Conclusion for Monochlorobenzene

.......................................................................................................................... 84 Nitrite (as N)

................................................................................................ ...................................................... 85 Results of the Methods Comparison

.......................................................................................................................... 85 Results of the PQL Analysis

................................................................................................ ...................................... 85
Conclusion for Nitrite

................................................................................................ ................................................ 86 Styrene

................................................................................................ ................................................................ 87 Results of the Methods Comparis on

.......................................................................................................................... 87 Results of the PQL Analysis

................................................................................................ ...................................... 87 Conclusion for Styrene

................................................................................................ .............................................. 88
T

oluene

................................................................................................ ............................................................... 89 Results of the Methods Comparison

.......................................................................................................................... 89 Results of the PQL Analysis

................................................................................................ ...................................... 89
Conclusion for Toluene

................................................................................................ ............................................. 90EPA

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- 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

- 1,2

- Dichloroethylene

................................................................................................ ................................ 99 Results of the Methods Comparison

.......................................................................................................................... 99 Results of the PQL Analysis

................................................................................................ ...................................... 99
Conclusion for trans

- 1,2

- 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 Co mparison

........................................................................................................................ 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

................................................................................................ ....................................................... 107
Arsenic

................................................................................................ ............................................................. 107 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

................................................................................................ .......................................................... 111

Results of the Methods Comparison

........................................................................................................................ 111 Results of the PQL Analysis

................................................................................................ .................................... 111
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

................................................................................................ ........................................... 118EPA

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................................................................................................ ............................................................ 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

................................................................................................ ............................................................ 127 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 Compari son

........................................................................................................................ 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 fo r Lead

................................................................................................ ................................................ 140 Mercury

................................................................................................ ............................................................ 141 Results of the Methods Comparison

........................................................................................................................ 141
Res ults 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 Analysi s

................................................................................................ .................................... 145 Conclusion for Oxamyl

................................................................................................ ............................................ 146 Picloram

................................................................................................ ........................................................... 147

Results of the Meth ods Comparison

........................................................................................................................ 147 Results of the PQL Analysis

................................................................................................ .................................... 147
Conclusion for Picloram

................................................................................................ .......................................... 148EPA

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................................................................................................ ........................................................... 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-1

Appendix B: Radionuclide Regressions ................................................................................. B-1

ALPHABETICAL LIST OF ANALYTE PROFILES

1,1,1-Trichloroethane .................................................................................................................................. 93 1,1,2-Trichloroethane .................................................................................................................................. 37 1,1-Dichloroethylene .................................................................................................................................. 79 1,2,4-Trichlorobenzene ............................................................................................................................... 91 1,2-Dibromo-3-chloropropane (DBCP ....................................................................................................... 45 1,2-Dichlorobenzene ................................................................................................................................. 121 1,2-Dichloroethane (Ethylene ..................................................................................................................... 29 1,2-Dichloropropane ................................................................................................................................... 31 1,4-Dichloroben zene ................................................................................................................................... 75 2,4,5- TP (Silvex) ....................................................................................................................................... 105 2,4- Dichlorophenoxyacetic acid (2,4

- D) .................................................................................................. 123
Alachlor ...................................................................................................................................................... 41 Antimony .................................................................................................................................................... 43
Arseni c ...................................................................................................................................................... 107
Atrazine ....................................................................................................................................................... 95
Barium ........................................................................................................................................................ 73
Benzene ....................................................................................................................................................... 23 Benzo(a)pyrene ........................................................................................................................................... 57 Beryllium .................................................................................................................................................. 109
Bromate ....................................................................................................................................................... 59
Cadmium ................................................................................................................................................... 111
Carbofuran .................................................................................................................................................. 97
Carbon Tetrachloride .................................................................................................................................. 25
Chlordane .................................................................................................................................................... 27
Chromium ................................................................................................................................................. 113
cis -1,2-Dichloroethylene ............................................................................................................................. 77 Copper ....................................................................................................................................................... 115 Cyanide ..................................................................................................................................................... 117 Dalapon ..................................................................................................................................................... 119EPA

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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 dibr omide (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
Oxa myl (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 Trichloroethyle ne ........................................................................................................................................ 39 Viny l C hloride ............................................................................................................................................ 55 Xylenes (total) ........................................................................................................................................... 153EPA

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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 Regulate d Analytes 16

Exhibit 4: Analytical Methods for Benzene................................................................................. 23

Exhibit 5: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data

– Be nzene .......................... 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

Ex hibit 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

Exhi bit 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 ...... 50EPA

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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 35: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data – Toxaphene .................... 54

Exhibit 36: Analytical Methods fo r 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

Ex hibit 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 for PCBs: As Decachlorobiphenyl .......................................... 69

Exhibit 51: Analytical Methods for PCBs: 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

Exhi bit 59: Analytical Methods for c is -1,2- Dichloroethylene .................................................... 77

Exhibit 60: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data

– cis -1,2- 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 .... 80EPA

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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 trans -1,2-Dichloroethylene ................................................. 99

Exhibit 82: Evaluation of Six- Yea r 1 and Six- Year 2/ERA PT Data

– trans -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 for Methoxychlor .................................................................... 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

Exhi bit 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........................................................................... 111EPA

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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-e thylhexyl)adipate .................................................. 125

Exhibit 108: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data

– DEHA ....................... 126

Exhibit 109: Analytical Methods for Dinoseb ........................................................................... 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 for Endothall ......................................................................... 131

Exhibit 114: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data – Endothall .................. 132

Exhibit 115: Analytical Methods for Endrin ............................................................................. 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

Exhi bit 121: A nalytical Methods for Lead ................................................................................ 139

Exhibit 122: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data

– Lead .......................... 140

Exhibit 123: Analyt ical Methods for Mercury ........................................................................... 141

Exhibit 124: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data

– Mercury .................... 142

Exhibit 125: Analy tical Methods for Nitrate ............................................................................. 143EPA

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### Exhibit 126: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data

– Nitrate ....................... 144

Exhibit 127: Anal ytical Methods for Oxamyl ........................................................................... 145

Exhibit 128: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data

– Oxamyl ..................... 146

Exhibit 129: Analy tical Methods for Picloram .......................................................................... 147

Exhibit 130: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data

– Picloram .................... 148

Exhibit 131: An alytical 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 R eview Analytical Feasibility Assessment Summary Analytes with MCL Greater than the Current PQL and Thus it is Technically Feasible to Reduce the MCL
- 41 A nalytes ............................................................................................................................... 160

Appendix A

Exhibit A-1: New or Revised Analytical Methods since 2000; Review of NPDWRs under 40
CFR §§141.23, 141.24, and 141.131 .......................................................................................... A-1

Appendix B

Exhibit B-1: U.S. EPA National Primary Drinking Water Standards and Re lated Information

– Radionuclides .............................................................................................................................. B-1

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

Exhibi t 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 : Evaluatio n of ERA PT Data

– Gross Beta ............................................................ B-8

Exhibit B-8: Evaluation of ERA PT Data – Barium -133 .......................................................... B-9

Exhibi t B-9: Evaluation of ERA PT Da ta – Cobalt-60 ............................................................ B-10

Exhibit B-10: Evaluation of ERA PT Data – Cesium -134 ...................................................... B-11

Exhibit B-11: Evaluation of ERA PT Data – Cesium -137 ...................................................... B-12

Exhibit B-12: Evaluation of ERA PT Data – Iodine-131 ........................................................ B-13EPA

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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-17Page xx 

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### 1.0 Introduction

The Safe Drinking Water Act (SDWA), as am ended 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 t he process and strategy EPA uses to review existing
NPDWRs in order t o meet its statutory requirement. T he 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 enable s 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 wher e appropriate, EPA review s 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., monitori ng 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 regulatio ns 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 L evel 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 l imits 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 Accred itation Conference (NELAC) providing oversight.

Anal ytical 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 suppor ted by the approval and availability of new/improved methods to the testing laboratories.

For t he first Six

- Year Review, EPA performed PQL assessme nts 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.EPA

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Page 2 **•** 

### 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

- bru sh 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

c oncentrations of interest, or the results were inconclusive/inadequate regarding a potential to
revi se 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 B ackground

2.1 Relationship Between SDWA Requirements and Analytical Methods

Section 1401(1)( C)(i) of SDWA (as amended in 1996); 42 U.S.C. § 300f(1)(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." Accordi ng 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 lev els " [ § 1401(1)(D) of SDWA ; 42 U.S.C. § 300f(1)(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 w ere 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, someEPA

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### laboratories may have improved in their ability to measure at lower levels using the same
method s 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 speci fied l imits 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 da y- 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 fol lowing (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 addi tion , 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 secon dary 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 theEPA

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### concentration of an analyte at which 75% of all participating laboratories achiev ed 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
int erferences 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 inorganic s typically range f rom 15 to 30% (40 CFR § 141.23(k)(3)(ii)), the acceptance limits for organic s
ge nerally 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

perc entage 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

approa ch, 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

.

Ther e are advantages and disadvantages for each of these approaches. Some of the advantages and disadvantages for these PQL derivation app roaches 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 t he analysis of that contaminant.

**•** 

### May be the prefe rred 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

.EPA

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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

som e 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 demonstrat e 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

sa mples 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 d ri nking 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 m ethods 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.EPA

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### 2.3 Operational Details of the PE/ PT Programs

PE st udies were an integral part of EPA's certificati on 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, inc luding 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 pro duced 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 eva luation, 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 pr ogram. 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.

P riva tization of the PT program made it harder f

or 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 ra tes; 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 concentr ation. 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 (NELA C now refers to these as Acceptance Criteria) for each analyte. Acceptance Criteria can be percentage based ( e.g. , + 30% of the spiked, or true value), standard deviation- bas ed ( e.g. , + 2EPA

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### standard deviations, as described in Section 5.2), or based on aver age 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. , + 40% for spike

conce ntrations <10 **μ** g/L and + 20% for concentrati ons > 10 **μ** g/L ).

The key differences between EPA’s PE program and the current NELAC PT program in

ter ms of the utility of the data for PQL assessment are described in Exhibit 1. For PQL assessment, the most significant implication of the differences betw een 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 concen trations for PT samples were selected below the current PQLs.

Exhib it 1: Summary of Differences Between EPA’s PE Program and NELAC’s PT Progra m 1

Laboratory Accreditation Program Feature During EPA PE Period During NELAC PT Period

Number of Laboratorie s Participating Wide range but typically 10

- 60 laboratories per concentration Wide range but typically 10

- 70 laboratories per concentration Types of Laboratories Participating EPA Regional and State
laboratories - Narrow spectrum of
laboratories and r elatively uniform in performance Public Water System, academic and private with some EPA regional and State laboratories - Broad spectrum of laboratories with wide performance range Number of True (Spike) Concentrations Evaluated/ analyte Approximately 1 0

- 30 59

- 60

Number of True (Spike) Concentrations Below the PQL Of the 66 analytes which had PE data for PQL assessment, 39 analytes had data < the current PQL 2 Of the 66 analytes which had PT data for PQL assessment, 22 analytes had data < the current PQL
Amount of Data Available to EPA for PQL Assessment (% of the National PT data) Percentage unknown Approximately 50% of the
national PT data

Data Broken Down by Analytical Method? Yes No

1 Excludes radionuclides

2 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 PQLEPA

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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 nationallyrepresentative PT data from the private firms that now provide PT ser vices and/or directly from
NELAC:

EPA f irst searched the websites of various PT providers to find out if the laboratory perf ormance 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 rat es 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/fa iling rates at each concentration that were needed for PQL assessment.

3.0 Represen tativeness 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
webs ite 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.EPA

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### 3.1 Bias

The refusal of providers other than ERA to provide data introduces potential nonresponse 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 exi sting 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 be tween 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, qual ity 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

nee d ed 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 willi ng 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

- α , where α is the probability of a type I error. In other words, the proba bility that the prediction interval includes the true regression line is 1- α percent. It is common to estimate either a 95 percent or 99 percent prediction interval.

Sampl ing 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.EPA

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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) Y i 

### = β 0 

### + β 1 

### x i 

### + **ε** i



### Where:

Y i 

### = Dependent variable for observation i. (e.g., laboratory passing rate for true concentration i) ; β 0 

### = Intercept or constant which tells us the expected value of Y when X is equal to zero. (e.g.,
the observed concent ration in a sample that has not been spiked); β 1 

### = The slope, or the change in Y for a change in x;

x i 

### = The independent variable for observation i (the true concentration for observation i);

**ε**

i 

### = Random error, or th e 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) Ŷ i 

### = b 0 

### + b 1 

### x

Where :

Ŷ i 

### = The fitted value predicted by the model.

The parameters b 0 

### and b 1 

### are unbiased estimates of β 0 

### and β 1 

### (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 **ε** i 

### in equation (1). The parts of the error are independent, so the variance of the pr ediction error is the sum of the three variances. Even if the reg ression estimate is based on the entire (finite) population, these last two components of error remain.EPA

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### 4.0 Identif ication of Regulated Analytes for PQL Assessment

For the first Six

- Year analytical feasibility review, EPA focused on assessing whether th e PQL had changed since promulgation for a subset of the 68 chemical NPDWRs. EPA identified and performed the analytical feasibility analysis fo r 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 o f MDLs, current PQL, how the PQL wa s determined, their MCLG, MCL, and the current acceptance criteria for

PT.

Exhibit 2: U.S. EPA National Primary Drinking Water Standards and Related
Information 1

Analyte
CASRN EPA MDL or Range (mg/L) 2 PQL (mg/L) How PQL Determined? MCLG (mg/L) MCL or TT (mg/L) Acceptance Criteria

Acrylamide

79

- 06 -1 N/A N/A N/A Zero TT 3 N/A

Alachlor

15972

- 60 -8 0.000005 - 0.000225 0.002 IMDL x 10 Zero 0.002 + 45%

Antimony

7440

- 36 -0 0.00002 - 0.0008 0.006 PE Data 0.006 0.006 + 30%

Arsenic

7440

- 38 -2 0.0001

- 0.008 0.00 3 PE Data Zero 0.010 + 30%

Atrazine

1912

- 24 -9 0.000003 - 0.0024 0.001 PE Data 0.003 0.003 + 45%

Barium

7440

- 39 -3 0.00004

- 0.001 0.15 PE Data 2 2 + 15%

Benzene

71

- 43 -2 0.00001 - 0.00004 0.005 RDL x 10 Zero 0.005 + 20% or 40%

Benzo[a]pyrene

50

- 32 -8 0.000016 - 0.00023 0.0002 PE Data Zero 0.0002 Mean + 2 Std Dev
Beryllium

7440

- 41 -7 0.00002 - 0.0003 0.001 PE Data 0.004 0.004 + 15%

Bromate

15541

- 45 -4 0.00012 - 0.00144 0.01 N/A Zero 0.01 Mean + 2 Std Dev (changed to

+ 30% , 2007)

Cadmium

7440

- 43 -9 0 .00003 - 0.001 0.002 PE Data 0.005 0.005 + 20%

Carbofuran

156 3

- 66 -2 0.000043

- 0.00052 (note: lower
bound = DL) 0.007 IMDL x 10 0.04 0.04 + 45%

Carbon tetrachloride

56

- 23 -5 0.000002 - 0.00021 0.005 PE Data Zero 0.005 + 20% or 40%

Chlordane

57

- 74 -9 0.000001 – 0.00022 4 0.002 IMDL x 10 0.002 0.002 + 45%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 12 Analyte
CASRN EPA MDL or Range (mg/L) 2 PQL (mg/L) How PQL Determined? MCLG (mg/L) MCL or TT (mg/L) Acceptance Criteria

Chlorite

775 8

- 19

- 2 0.00045 - 0.01 N/A N/A 0.8 1.0 + 30%

Chromium (total)
Cr III: 16065

- 83 -1
Cr VI: 18540

- 29 -9 0.00008 - 0.004 0.01 PE Data 0.1 0.1 + 15%

Copper

744 0

- 50 -8 0.00001 - 0.003 0.05 PE Data 1.3 TT 5 Action level
1.3 + 10 %

Cyanide ( as free cyanide)

57

- 12 -5 N/A 0.1 PE Data 0.2 0.2 + 25%

Dalapon

75

- 99 -0 0.000024 - 0.0013 0.01 MDL x 10 0.2 0.2 Mean + 2 Std Dev

1,2

- D ibromo -3- chloropropane (DBCP)

96

- 12 -8 0.000006 - 0.00001 0.0002 IMDL x 10 Zero 0.00 02 + 40%

1,2

- D ichlorobenzene ( o

- Dichlorobenzene)

95

- 50 -1 0.00002 - 0.00005 0.005 MDL survey
and PE Data 0.6 0.6 + 20% or 40%

1,4

- D ichlorobenzene ( p

- Dichlorobenzene)

106

- 46 -7 0.00001 - 0.00004 0.005 PE Data 0.075 0.075 + 20% or 40%

1,2

- D ichloroethane (Ethylene dichloride)

107

- 06 -2 0.00002 - 0.00006 0.005 PE Data Zero 0.005 + 20% or 40%

1,1

- D ichloroethylene

75

- 35

- 4 0.00004 - 0.00012 0.005 PE Data 0.007 0.007 + 20% or 40%

cis

- 1, 2

- Dichloroethylene

156

- 59

- 2 0.00001 - 0.00012 0.005 MDL survey
and PE Dat a 0.07 0.07 + 20% or 40%

trans

- 1,2

- Dichloroethylene

156

- 60

- 5 0.00003 - 0.00006 0.005 MDL survey
and PE Data 0.1 0.1 + 20% or 40%

Dichloromethane ( Methylene chloride)

75

- 09 -2 0.00001 - 0.00009 0.005 PE Data Zero 0.005 + 20% or 40%

2,4

- D ichlorophenoxyacet ic acid (2,4

- D)

94

- 75 -7 0.000055 - 0.0013 0.005 Raised to near MCL 0.07 0.07 + 50%

1,2

- D ichloropropane

78

- 87 -5 0.00001 - 0.00004 0.005 MDL survey
and PE Data Zero 0.005 + 20% or 40%

Di(2

- et hylhexyl)adipate (DEHA)

103

- 23 -1 0.00009 - 0.01182 0.006 MDL x 10 0.4 0.4 Mean + 2 Std Dev

Di(2

- et hylhexyl) phthalate (DEHP)

117

- 81 -7 0.00046 - 0.00225 0.006 PE Data Zero 0.006 Mean + 2 Std Dev

Dinoseb

88

- 85 -7 0.000081 - 0.0015 0.002 MDL x 10 0.007 0.007 Mean + 2 Std Dev
Diquat

85

- 00 -7 0.00072 0.004 PE Data 0.02 0.02 Mean + 2 Std Dev

Endothall

145

- 73 -3 0.0007 - 0.00179 0.09 MDL x 10 0.1 0.1 Mean + 2 Std DevEPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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CASRN EPA MDL or Range (mg/L) 2 PQL (mg/L) How PQL Determined? MCLG (mg/L) MCL or TT (mg/L) Acceptance Criteria

Endrin

72

- 20 -8 0.000002 - 0.00034 0.0001 MDL x 10 0.002 0.002 + 30%

Epichlorohydrin

106

- 89 -8 N/A N/A N/A Zero TT 3 N/A

Ethylbenzene

100

- 41 -4 0.00001 - 0.00006 0 .005 MDL survey
and PE Data 0.7 0.7 + 20% or 40%

Ethylene dibromide ( EDB)

106

- 93 -4 0.000007 - 0.000032 0.00005 IMDL x 5 Zero 0.00005 + 40%

Fluoride

169 84

- 48 -8 0.009 - 0.01 0.5 PE Data 4 4 + 10%

Glyphosate

107 1

- 83 -6 0.00599 - 0.006 0.06 PE Data 0.7 0.7 M ean + 2 Std Dev
Heptachlor

76

- 44 -8 0.0000015 - 0.00015 0.0004 IMDL x 10 Zero 0.0004 + 45%

Heptachlor epoxide

1024

- 57 -3 0.000001 - 0.000202 0.0002 IMDL x 10 Zero 0.0002 + 45%

Hexachlorobenzene

118

- 74 -1 0.000001 - 0.00013 0.001 PE Data Zero 0.001 Mean +
2 S td Dev
Hexachlorocyclopenta

di ene
77

- 47 -4 0.000004 - 0.00016 0.001 PE Data 0.05 0.05 Mean + 2 Std Dev

Lead

743 9

- 92 -1 0.00002 - 0.0007 0.005 PE Data Zero TT 5 , Action level =
0.015 + 30%

Lindane

58

- 89 -9 0.000002 - 0.00015 0.0002 MDL x 10 0.0002 0.0002 + 45%

Mercury (Inorganic)

743 9

- 97 -6 0.0000018 - 0.0002 0.0005 PE Data 0.002 0.002 + 30%

Methoxychlor

72

- 43 -5 0.000003 - 0.00096 0.01 Raised to near MCL 0.04 0.04 + 45%

Monochlorobenzene ( Chlorobenzene)

108

- 90 -7 0.00001 - 0.00004 0.005 MDL x 10 0.1 0.1 + 20% or 40%

Nitrate (as N)

147 97

- 55 -8 0.002 - 0.008 0.4 PE Data 10 10 + 10%

Nitrite (as N)

147 97

- 65 -0 0.001 - 0.004 0.4 PQL for
nitrate 1 1 + 15%

Oxamyl (Vydate)

231 35

- 22 -0 0.000044 - 0.00086 0.02 MDL x 10 0.2 0.2 Mean + 2 Std Dev
Pentachlorophenol

87 -86-5 0.000014 - 0.0016 0.001 PE Data Zero 0.001 + 50%

Picloram

191 8

- 02 -1 Not
Recovered - 0.001 0.001 DL x 10 0.5 0.5 Mean + 2 Std Dev

Polychlorinated
bi phenyls (PCBs) as Decachlorobiphenyl (DCBP)

1336

- 36 -3 As
Decachlorobi

phenyl (DCBP):
0.00008

As Arocl o rs: 0.000012 -

0.015 6 0.0005 PE Data Zero 0.0005 + 100%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 14 Analyte
CASRN EPA MDL or Range (mg/L) 2 PQL (mg/L) How PQL Determined? MCLG (mg/L) MCL or TT (mg/L) Acceptance Criteria

Selenium

778 2

- 49 -2 0.0005 - 0.0079 0.01 PE Data 0.05 0.05 + 20%

Simazine

122

- 34 -9 0.000008 - 0.0068 0.0007 MDL x 10 0.004 0.004 Mean + 2 Std Dev Styrene

100

- 42 -5 0.00001 - 0.0001 0.005 MDL survey
and PE Data 0.1 0.1 + 20% or 40%

2,3,7,8

- T CDD (Dioxin)

1746

- 01 -6 1.E

- 8 (note: value

is an ML) 3 x 10 -8 MDL x 5 Zero 3 x 10 -8 Mean + 2 Std Dev

Tetrachloroethylene

127

- 18

- 4 0.000002 - 0.00014 0.005 MDL survey
and PE Data Zero 0.005 + 20% or 40%

Thallium

744 0

- 28 -0 0.00001 - 0.0007 0.002 PE Data 0.0005 0.002 + 30%

Toluene

108

- 88 -3 0.00001 - 0.00011 0.005 MDL survey
and PE Data 1 1 + 20% or 40%

Toxaphene

800 1

- 35 -2 0.00013 - 0.0017 0.003 PE Data Zero 0.003 + 45%

2,4,5

- TP ( Silvex)

93

- 72 -1 0.000018 - 0.0018 0.005 Raised to near MCL 0.05 0.05 + 50%

1,2,4

- T richlorobenzene

120

- 82 -1 0.00002 - 0.0002 0.005 MDL x 10 0.07 0.07 + 20% or 40%

1,1,1

- T richloroethane

71

- 55

- 6 0.000005 - 0.00008 0.005 DL x 10 0.2 0.2 + 20% or 40%

1,1,2

- T richloroethane

79

- 00

- 5 0.000012 - 0.0001 0.005 PE Data 0.003 0.005 + 20% or 40%

Trichloroethylene

79

- 01 -6 0.000002 - 0.00019 0.005 PE Data Zero 0.005 + 20% or 40%

Vinyl chloride

75

- 01 -4 0.00001 - 0.00018 0.002 MLPD Zero 0.002 + 40%

Xylenes (total)

133 0

- 20 -7 0.00001 - 0.00013 0.005 MD L survey
and PE Data 10 10 + 20% or 40%

1 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 = I nterlaboratory Method Detection Limit

MDL = Method Detection Limit

ML = Minimum Level

MLPD = Multi

- laboratory Performance Data

PQL = Practical Quantitation Level
RDL = Regulatory Detection Limit

2 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).

3 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 levelEPA

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Page 15 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 **α−** and **γ−** 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 a dditional 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 315 16 , August 18, 1988; 54 FR 22062, May 2 2, 1989; 55 FR 30370, July 25, 199 0; 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 141.131(b )(2)(ii).



### 5.0 Se cond 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 pa ssing 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 laborato ry 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 o f 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
concl usions are drawn regarding changes in PQLs.EPA

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Page 16 

### Exhibit 3: Availability of Six -Year 1 PE Data and Six-Year 2 PT Data for Regulated
Anal ytes

Analyte
CASRN In Six

- Year 1 Data? In Six

- Year 2 ERA Data
1999

- 2004?
Acrylamide

79

- 06 -1 No No

Alachlor

159 72

- 60 -8 Y es
, some data < PQL Y es
, no data < PQL

Antimony

744 0

- 36 -0 Y es
, some data < PQL 1 Y es
, no data < PQL

Arsenic

744 0

- 38 -2 Y es
, some data < PQL 1 Y es
, no data < PQL

Atrazine

191 2

- 24 -9 Y es
, some data < PQL 1 Y es
, no data < PQL

Barium

744 0

- 39 -3 Y es
, some data < PQL 1 Y es
, no data < PQL

Benzene

71

- 43 -2 Y es
, some data < PQL Y es
, some data < PQL

Benzo[a]pyrene

50

- 32 -8 Y es
, no data < PQL Y es
, no data < PQL

Beryllium

744 0

- 41 -7 Y es
, some data < PQL Y es
, no data < PQL

Bromate

155 41

- 45 -4 Y es
, some dat a < PQL Y es
, some data < PQL

Cadmium

744 0

- 43 -9 Y es
, no data < PQL Y es
, no data < PQL

Carbofuran

156 3

- 66 -2 Y es
, some data < PQL Y es
, no data < PQL

Carbon tetrachloride

56

- 23 -5 Y es
, some data < PQL Y es
, some data < PQL

Chlordane

57

- 74 -9 Y es
, some data < PQL Y es
, no data < PQL

Chlorite

775 8

- 19

- 2 Y es , but no PQL Y es , but no PQL

Chromium (total)
C r III: 16065

- 83 -1
Cr VI: 18540

- 29 -9 Y es
, no data < PQL Y es
, no data < PQL

Copper

744 0

- 50 -8 Y es
, some data < PQL 1 Y es
, no data < PQL

Cyanide ( as free cyanide)

57

- 12 -5 Y es , only one datum = PQL; no data < PQL Y es
, no data < PQL

Dalapon

75

- 99 -0 Y es
, some data < PQL; passing rates below PQL could not be
calculated 2 Y es
, no data < PQL

1,2

- D ibromo -3- chloropropane (DBCP)

96

- 12 -8 Y es
, some data < PQL Y es
, some data < PQL

1,2

- D ichlorobenzene ( o

- Dichlorobenzene)

95

- 50 -1 Y es , no data < PQL Y es
, no data < PQLEPA

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Page 17 Analyte
CASRN In Six

- Year 1 Data? In Six

- Year 2 ERA Data
1999

- 2004?

1,4

- D ichlorobenzene ( p

- Dichlorobenzene)

106

- 46 -7 Y es
, some data < PQL Y es
, some data < PQL

1,2

- D ichloroethane (Ethylene dichloride)

107

- 06 -2 Y es
, some data < PQL 1 Y es
, some data < PQL

1,1

- D ichloroethylene

75

- 35

- 4 Y es
, no data < PQL Y es
, some data < PQL

cis

- 1, 2

- Dichloroethylene

156

- 59

- 2 Y es
, no data < PQL Y es
, some data < PQL

trans

- 1, 2

- Dichloroethylene

156

- 60 -5 Y es
, no data < PQL Y es
, some data < PQL

Dich l oromethane (Methylene chloride)

75

- 09 -2 Y es
, no data < PQL Y es
, no data < PQL

2,4

- D ichlorophenoxyacetic acid (2,4

- D)

94

- 75 -7 Y es
, some data < PQL Y es
, no data < PQL

1,2

- D ichloropropane

78

- 87 -5 Y es
, no data < PQL Y es
, some data < PQL

Di(2

- et hylhexyl)adi pate (DEHA)

103

- 23 -1 Y es
, some data < PQL; passing rates below PQL could not be
calculated 2 Y es
, no data < PQL

Di(2

- et hylhexyl) phthalate (DEHP)

117

- 81 -7 Y es
, some data < PQL Y es
, no data < PQL

Dinoseb

88

- 85 -7 Y es
, no data < PQL Y es
, no data < PQL

Diquat

85

- 00 -7 Y es
, no data < PQL Y es
, no data < PQL

Endothall

145

- 73 -3 Y es
, some data < PQL; passing rates below PQL could not be
calculated 2 Y es
, no data < PQL

Endrin

72

- 20 -8 Y es
, no data < PQL 1 Y es
, no data < PQL

Epichlorohydrin

106

- 89 -8 No No

Ethylbenzene

100

- 41 -4 Y es
, no data < PQL Y es
, some data < PQL

Ethylene dibromide (EDB)

106

- 93 -4 Y es
, no data < PQL Y es
, no data < PQL

Fluoride

169 84

- 48 -8 Y es
, some data < PQL Y es
, no data < PQL

Glyphosate

107 1

- 83 -6 Y es
, no data < PQL Y es
, no data < PQL

Heptachlor

76

- 44 -8 Y es
, some data < PQL Y es
, no data < PQL

Heptachlor epoxide

102 4

- 57 -3 Y es
, some data < PQL Y es
, no data < PQL

Hexachlorobenzene

118

- 74 -1 Y es
, some data < PQL Y es
, some data < PQL

Hexachlorocyclopentadiene

77

- 47 -4 Y es
, some data < PQL Y es
, no data < PQLEPA

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Page 18 Analyte
CASRN In Six

- Year 1 Data? In Six

- Year 2 ERA Data
1999

- 2004?

Lead

7439

- 92 -1 Y es
, some data < PQL 1 Y es
, no data < PQL

Lindane

58

- 89 -9 Y es
, some data < PQL 1 Y es
, no data < PQL

Mercury (Inorganic)

7439

- 97 -6 Y es
, no data < PQL Y es
, no data < PQL

Methoxychlor

72

- 43 -5 Y es
, some data < PQL Y es
, no data < PQ L

Monochlorobenzene (Chlorobenzene)

108

- 90 -7 Y es
, no data < PQL Y es
, some data < PQL

Nitrate (as N)

147 97

- 55 -8 Y es
, no data < PQL Y es
, no data < PQL

Nitrite (as N)

147 97

- 65 -0 Y es
, some data < PQL Y es
, no data < PQL

Oxamyl (Vydate)

231 35

- 22 -0 Y es
, some data < PQL Y es
, no data < PQL

Pentachlorophenol

87

- 86 -5 Y es
, some data < PQL Y es
, no data < PQL

Picloram

191 8

- 02 -1 Y es
, no data < PQL Y es
, no data < PQL

Polychlorinated biphenyls (PCBs) as
D ecachlorobiphenyl (DCBP)

1336

- 36 -3 Y es
, some data < PQL Y es
, no data < PQL

Selenium

778 2

- 49 -2 Y es
, some data < PQL 1 Y es
, no data < PQL

Simazine

122

- 34 -9 Y es
, some data < PQL; passing rates below PQL could not be
calculated 2 Y es
, no data < PQL

Styrene

100

- 42 -5 Y es
, no data < PQL Y es
, some data < PQL

2,3,7,8

- T CDD ( Dioxin)

1746

- 01 -6 No Y es
, no data < PQL; only one spike level
Tetrachloroethylene

127

- 18

- 4 Y es
, no data < PQL Y es
, some data < PQL

Thallium

744 0

- 28 -0 Y es
, some data < PQL Y es
, no data < PQL

Toluene

108

- 88 -3 Y es
, no data < PQL Y es
, some data < PQL

Toxa ph ene
8001

- 35 -2 Y es
, some data < PQL Y es
, no data < PQL

2,4,5

- TP ( Silvex)

93

- 72 -1 Y es
, some data < PQL 1 Y es
, no data < PQL

1,2,4

- T richlorobenzene

120

- 82 -1 Y es
, no data < PQL Y es
, some data < PQL

1,1,1

- T richloroethane

71

- 55

- 6 Y es
, some data < PQL Y es , s om e data < PQL

1,1,2

- T richloroethane

79

- 00

- 5 Y es
, no data < PQL Y es
, some data < PQL

Trichloroethylene

79

- 01 -6 Y es
, no data < PQL Y es
, some data < PQLEPA

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Page 19 Analyte
CASRN In Six

- Year 1 Data? In Six

- Year 2 ERA Data
1999

- 2004?
Vinyl chloride

75

- 01 -4 Y es
, no data < PQL Y es , some data < PQL

Xylenes (total)

1330

- 20

- 7 Y es , no dat a < PQL Y es , some data < PQL

1 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.

2 Means passing rates for Si x- 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 Calcu lating 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 priori tized 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 As sessment using
the Six

- Year 1 data.

The Acceptance Criteria that were set forth in various FR notices during the time of the

gener ation 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. , + 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

assess ment; 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 a cceptance cri teria had , apparently, been provided by EPA at that time, the Six- Year 1 regressions for theseEPA

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Page 20 

### 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, a nd 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 Reg ression 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 m ore than 60, with approximately 10 to 30 different concentrations evaluated. The number of laboratories that participate d 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 cas es where the acceptance criteria vary with concentration, the data points that were

less than 10 **μ** g/L a nd those that were greater than or equal to 10 **μ** g/ 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:

**•** 

### A crylamide: No PT data available.

**•** 

### Chlorite: Chlorite has no promulgated PQL.

**•** 

### Epichlorohydrin: No PT da ta available.

**•** 

### 2,3,7,8-Tetrachlorodibenzodioxin (TCDD – dioxin): Only one data point in the ERA data set, and no Six- Year 1 PT data

.EPA

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Page 21 

### 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

pe rformance of the analytical methods available for compliance monitor ing 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.

Des pite of using this two

- step approach, EPA had difficulty in making a quantitative assessment of the improvements in la boratory performance over time. There were severe limitations in the laboratory accreditation studies data, i.e. PE/ PT results were either not

ava ilable 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 e ach analyte, MDLs from EP A-approved methods are compared and a PQL
assessment i s 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 r eadily
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 P E 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 -Y ear 2 may suggest or not suggest potential changes to the PQL.

The r esults 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 pot ential for MCL reduction beyond the current PQL. T he P QL assessments were made and are presented in this report for a t otal 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.

U si ng 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,EPA

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Page 22 

### 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 re cent 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 determi nation 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 assessm ent 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 thi s 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 μg/L) . Only the current evaluations of the Six- Ye ar 1 and
Six

- Year 2/ERA data are presented in this report.

6.1 An alytes with M aximum Contaminant Level (MCL) E qual to the Current PQL and
T hus 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 C urrent 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.EPA

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Page 23 

### Benzene

Results of the Met hods 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.

Exhi bit 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 Technique MDL μg/L

502.2 CCGC with PID/ELC D 0.01

524.2 CCGC/ MS 0.03 - 0.04

Note s : 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 benzene is 5 μ g/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

concent rations below 10 μg/L and + 20% at or above 10 μ 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 μg/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

set s are at or above 75%.EPA

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Page 24 

### Exhibit 5: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data

– Benzene

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for Benzene

The high laboratory passing rates (well above 75%) at concentrations below the current PQL of 5 μg/L for both the Six- Year 1 and Si x -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 perfor mance in the vicinity of the current PQL (and hence suggest possible reduction of the PQ L) have been approved from 2000-2007.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 25 

### Carbon Tetrachloride

Results of the Methods Comparison

Exhibit 6 summarizes the MDLs for carbon tetrachloride as documented in EPAdeveloped 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 Carb on 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 Technique MDL μg/L

502.2 CCGC with PID/ELCD 0.01 - 0.02

524.2 C CGC/ MS 0.08 - 0.21

551.1 LL E/GC w/ ECD 0.002

- 0.050

Note s : 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 μ g/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 o f the March 2003 report. Note that the acceptance criteria are + 40% at spike concentrations below 10 μ g/L and + 20% at or above
10 μ 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 μg/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).EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 26 

### Exhibit 7: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data

– Carbon Tetrachloride

0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for Carbon Tetrachloride

The high laboratory passing rates ( well above 75%) at concentrations below the current PQL of 5 μg/L for both the Six- Year 1 and Si x -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 suppo rts 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 27 

### 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 Exhib it 8 represent ranges for chlordane, **α** -chlordane,

**γ** -chlordane, cis -nonachlor and trans -nonachlor). 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: Analyt ical 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 Technique MDL μg/L

505 ME and GC 0.006 - 0.14

508 GC/ ECD 0.0016

– 0.0041

508.1 LSE and ECGC 0.001

– 0.004

525.2 LSE and CCGC/MS 0. 05

– 0.22

Note s : 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 chlordane is 2 μ g/L. The Six -Year 1 and Six- Year 2/ERA da ta 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 μ g/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 28 

### Exhibit 9: Evaluation of S ix -Year 1 and Six

- Year 2/ERA PT Data – Chlordane

0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 45%

Current PQL = 2 ug/L 75%



### Conclusion for Chlordane

The high laboratory pas sing rates (well above 7 5%) at concentrations below the current PQL of 5 μg/L for the Six

- Year 1 data set s uggest that the PQL coul d 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 b e 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 815 -B- 09

- 003
October 2009

Page 29 

### 1,2- Dichloroethane (Ethylene dichloride)

Results o f the Methods Comparison

Exhibit 10 summarizes the MDLs for 1,2-dichloroethane as documented in EPAdeveloped 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 Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.03

524.2 CCGC/ MS 0.02 - 0.06

Note s : 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
141.2 4(f)(17)(i).



### Results of the PQL Analysis

The current PQL for 1,2-dichloroethane is 5 μ g/L . The Six

- Year 1 and Six

- Year 2/ ERA data sets are regressed separately (see Exhibit 11 ). The Six

- Year 1 P E 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 μg/L and + 20% at or
above 10 μ 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 μg/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 30 

### Exhibit 11: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data – 1,2- Dichloroethane

0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for 1,2-Dichloroethane

The high laboratory passing rates ( well above 75%) at concentrations below the current PQL of 5 μg/L for both the Six- Year 1 and Si x

- Year 2/ERA da ta 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 31 

### 1,2-Dichloropropane

Results of the Methods Comparison

Exhibit 12 summarizes the MDLs for 1,2-dichloropropane as documented in EPAdeveloped 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 Te chnique MDL μg/L

502.2 CCGC with PID/ ELCD 0.01 - 0.03

524.2 CCGC/ MS 0.02 - 0.04

Note s : 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
1 41.24(f)(17)(i).



### Results of the PQL Analysis

The current PQL for 1,2-dichloropropa ne is 5 μ g/L . The Six

- Year 1 and Six

- Year 2/E RA data sets are regressed separately (see Exhibit 13). The Six

- Year 1 P E 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 μg/L and + 20% at or
above 10 μ g/L ; hence the data are regressed as two independent populations. No Six- Year 1 data
are available below the current PQL of 5 μ g/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%).EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 32 

### Exhibit 13: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – 1,2-Dichloropropane

0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for 1,2-Dichloropropane

The hi gh laboratory passing rates (well above 75 %) at concentrations below the current PQL of 5 μg/L for the Six

- Year 2/ ERA data set sug gests 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 33 

### Hexachlorobenzene

Results of th e Methods Comparison

Exhibit 14 summarizes the MDLs for hexachlorobenzene as documented in EPAdeveloped 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 Tec hnique MDL μg/L

505 ME and GC 0.002

508 GC/E CD 0.0077

508.1 L/S E xtraction and ECGC 0.001

525.2 LSE and CCGC/MS 0.049

- 0.13

551.1 LLE/GC w/ ECD 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 μ g/L . The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhib it 15). The Six

- Year 1 P E 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 μ g/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).EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 34 

### Exhibit 15: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Hexachlorobenzene

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 μg/L for both the Six- Year 1 and Six

- Ye ar 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. 0 10 20 30 40 50 60 70 80 90 100

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate

Acceptance Criteria

= Mean + 2 SD

Current PQL = 1 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 35 

### 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 Technique MDL μg/L

502.2 CCGC with PID/ELCD 0.02 - 0.05

524.2 CCGC/M S 0.05 - 0.14

551.1 LLE /GC w/ ECD 0.002

- 0.008

Note s : 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 μ g /L . The Six

- Y ear 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 17). The Six

- Year 1 P E 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 μg/L and + 20% at

or a bove 10 μ g/L ; hence the data are regressed as two independent populations. No Six- Year 1
data are available below the current PQL of 5 μ 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 passin g rates are above 75%. Furthermore, the regression lines are also well above 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 36 

### Exhibit 17: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Tetrachloroethylene

Conclusion for Tetrachloroethylene

T he hi gh laboratory passing rates (well ab ove 75%) at concentrations below the current PQL of 5 μg/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% wh ich 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. 0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 37 

### 1,1,2-Trichloroethane

Results of the Methods Comparison

Exhibit 18 summarizes the MDLs for 1,1,2-trichloroethane as documented in EPAdeveloped 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 1,1,2- Trichloroethane

MCL = 0.005 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L
Ac ceptance Criteria = + 20% or 40% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.04

524.2 CCGC/MS 0.03 - 0.10

551.1 L LE/GC w/ ECD 0.012

- 0.017

Note s : The regulatory DL for volatile organ ic 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 1,1,2-trichloroethane is 5 μ g/L

. The Six

- Year 1 and Six -Y ear 2/ERA data sets are regressed separately (see Exhibit 19). The Six

- Year 1 P E 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 μg/L and + 20% at or

a bove 10 μg/L ; hence the data are regressed as two independent populations. No Six- Year 1 data
are available below the current PQL of 5 μ g/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 38 

### Exhibit 19: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – 1,1,2- T richloroethane

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate



### Conclusion for 1,1,2-Trichloroethane

The hi gh laboratory passing rates (well above 75 %) at concentrations b elow the current PQL of 5 μg/L for the Six

- Y ear 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. 0 10 20 30 40 50 60 70 80 90 100% Laboratories Passing

Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 39 

### 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 M ethods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.01

- 0.06

524.2 CCGC/MS 0.02

- 0.19

551.1 LLE/GC w/ ECD 0.002

- 0.042

Note s : 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 μg/L . The Six

- Y ear 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 21 ). The Six

- Year 1 P E 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 μg/L a nd + 20% at or above 10

μ g/ L ; hence the data are regressed as two independent populations. No Six- Year 1 data are below the current PQL of 5 μ 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 40 

### Exhibit 21: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Trichloroethylene

Conclusion for Trichloroethylene

T he high laboratory passing rates (well above 75 %) at concentrations below the current PQL of 5 μg/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. 0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 41 

### 6.1.2 P QL Assessment May Support Reduction of the C urrent PQL

O f the 25 analytes mentioned in Section 6.1, e ight analytes have an existing PQL that is equal to the MCL and their PE/ PT data suggest that the PQL could possibly be lower.

A lachlor

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 = 0.0002 mg/L Acceptance Criteria = + 45% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

505 ME and GC 0.225

507 GC/N

- PD 0.14

508.1 LSE and ECGC 0.009

525.2 LSE and CCGC/MS 0.069 - 0.16

551.1 LLE/GC w/ ECD 0.005 - 0.025 Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18). Acceptance Criteria for syntheti c organic compounds are listed at 40 CFR 141.24(h)(19)(i)(B).



### Results of the PQL Analysis

T he current PQL for alachlor is 2 μ g/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 we re 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 μ g/L . However, none
of the Six

- Year 2/ERA data are below the curre nt 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 42 

### Exhibit 23: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Alachlor

0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 45%

Current PQL = 2 ug/L 75%



### Conclusion for Alachlor

T he Six

- Year 1 laboratory passing rates below and in the vicinity of the PQL of 2 μg/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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 43 

### 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 -1 ). These updates are associated with administrative and technical changes or clarifications that are not expecte d 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 Technique MDL mg/L

200.8 ICP/MS 0.00002

- 0.0004

200.9 GFAA 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).



### Resul ts 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 sp ike 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 44 

### Exhibit 25: Evaluat ion of Six -Year 1 and Six

- Year 2/ERA PT Data – Antimony

90 100

0 10 20 30 40 50 60 70 80

0.00 0.02 0.04 0.06 0.08 0.10 0.12
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 30%

Current PQL = 0.006 mg/L 75%



### Conclusion for Antimony

G iven 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 45 

### 1,2-Dibromo-3-chloropropane (DBCP)

Results of the Methods Comparison

Exhibit 26 summari zes the MDLs for 1,2-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 : Analytic al 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 Technique MDL μg/L

504.1 ME and GC 0.01

551.1 LLE /GC w/ ECD 0.006

- 0.009

Note s : 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 DBCP is 0.2 μg/L . The Six

- Year 1 and Six

- Y ear 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 μ 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 46 

### Exhibit 27: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – DBCP

Conclusion for 1,2- Dibromo -3-chloropropane

Gi ven the limited data below the current PQL of 0.2 μg/L but high laboratory passing

r ates ( well above 75 %) just below and in the vicinity of the PQL for both Six- Year 2/ER A 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. 0 10 20 30 40 50 60 70 80 90 100

0.0 0.5 1.0 1.5 2.0 2.5 3.0
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 40%

Current PQL = 0.2 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 47 

### 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 h eptachlor 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 Technique MDL μg/L

505 ME and GC 0.003

508 G C/ECD 0.0015

508.1 L SE and ECGC 0.005

525.2 LSE and CCGC/MS 0.059

- 0.15

551.1 LLE/GC w/ ECD 0.002

- 0.081

Note s : 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 heptachlor is 0.4 μ g/L

. The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 29). The Six

- Year 1 P E 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 μ g/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 48 

### Exhibit 29: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Heptachlor

90 100

0 10 20 30 40 50 60 70 80

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 45%

Current PQL = 0.4 ug/L 75%



### Conclusion for Heptachlor

Given the availability of limited dat a below the current PQL of 0.4 μ g/L , but relatively high labo ratory 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 Si x- 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 49 

### Heptachlor Epoxide

Results of the Methods Comparison

Exhibit 30 summarizes the MDLs for heptachlor epoxide as documented in EPAdeveloped 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 Technique MDL μg/L

505 ME and GC 0.004

508 G C/ECD 0.0059

508.1 L SE and ECGC 0.001

525.2 LSE and CCGC/MS 0.048

- 0.13

551.1 LLE/GC w/ ECD 0 .002

- 0.202

Note s : 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 heptachlor epoxide is 0.2 μ g/L. The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 31). The Six

- Year 1 P E 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 μ g/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 passi ng rates displayed significant variability. Furthermore, two of the Six

- Year 2/ERA passing rates near the PQL are below 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 50 

### Exhibit 31: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Heptachlor Epoxide

Conclusion for Heptachlor Epoxide

Given the availability of limited data below the current PQL of 0.2 μg/L , but relatively
hi gh laboratory passing rates (mostly >90%) below and in the vicinity of the PQL for the SixYear 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. 0 10 20 30 40 50 60 70 80 90 100

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 45%

Current PQL = 0.2 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 51 

### Lindane

Results of the Methods Comparison

Exhib it 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 M ethods 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 Technique MDL μg/L

505 ME and GC 0.003

508 GC/ ECD 0.006

508.1 LSE and ECGC 0.006

525.2 LSE and CCGC/MS 0.047

- 0.15

551.1 LLE/GC w/ ECD 0.002

- 0.017

Note s : 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 lindane is 0.2 μ g /L

. T he 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 μ g/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 52 

### Exhibit 33: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Lindane

Conclusion for Lindane

Given the availability of limited data below the current PQL of 0.2 μg/L , but relatively
hi gh laboratory passing rates (well above 75 %) below and in the vicinity of the PQL for the SixYear 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. 0 10 20 30 40 50 60 70 80 90 100

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 45%

Current PQL = 0.2 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 53 

### Toxaphene

Results of the Methods Comparison

Exhibit 34 summarizes the MDLs for toxaphene as documented in EPA-developed analytical method s. 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 = 0.001 m g/L Acceptance Criteria = + 45% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

505 ME and GC 1.0

508 G C/ECD Listed in Method; n o MDLs
determined


### 508.1 LSE and ECGC 0.13

525.2 LSE and CCGC/MS 1.0 - 1.7

Note s : 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 toxaphene is 3 μ g/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 μg/L . None of the Six- Year 2/ERA data are below the current PQL. A ll 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 54 

### Exhibit 35: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Toxaphene

Conclusion for Toxaphene

Given the availability of limited data below the current PQL of 3 μg/L , but relatively
hi gh laboratory passing rates (well above 75 %) below and in the vicinity of the PQL for the SixYear 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 some what 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. 0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 45%

Current PQL = 3 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 55 

### 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 Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.01

- 0.18

524.2 CCGC/MS 0.04 - 0.17

Note s : Th e 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 μ g/L

. The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 37). The Six

- Year 1 P E data for vinyl chloride were evaluated but were not regressed a s part of the March 2003 report. No Six- Year 1 data are
available below the current PQL of 5 μ g/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
line s are well above 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 56 

### Exhibit 37: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Vinyl Chloride

Conclusion for Vinyl Chloride

Given the availability of limited data below the current PQL of 2 μg/L , but relatively hig h laboratory pas sing rates (well above 75 %) below and in the vicinity of the PQL for the SixYear 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 sugg est possible reduction of the PQL) have been approved from 2000-2007. 0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 40%

Current PQL = 2 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### 6.1.3 PQL Assessment Does Not Suppo rt Reduction of the Current PQL or Data are
Insufficient to R each a C onclusion.

Of the 25 analytes mentioned in Section 6.1, e ight analytes have an ex isting PQL that is equal to the MCL and their PE/ PT data either indicate that the PQL should not be lower or their

P E/ PT data are insufficient to reach a conclusion.

Ben zo(a)pyrene

Results of the Methods Comparison

Exhibit 38 summ arizes 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 : Analytic al 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 Technique MDL μg/L

525.2 LSE and CCGC/MS 0.0 32 - 0.23

550 LLE/HPLC w/ CUV and FD 0.029

550.1 LSE/HPLC w/ CUV and FD 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)(1 9)(i)(B).



### Results of the PQL Analysis

The current PQL for benzo(a)pyrene is 0.2 μ g /L

. T he Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 39). The Six

- Year 1 P E data for benzo(a)pyrene were regressed as part of the Mar ch 2003 report. None of the Six- Year 1 or the Six

- Year 2/ERA
data set are below the current PQL of 0.2 μ g/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 %.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 58 

### Exhibit 39: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Benzo(a)pyrene

0 10 20 30 40 50 60 70 80 90 100

0.0 0.5 1.0 1.5 2.0 2.5 3.0
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= Mean + 2 SD

Current PQL = 0.2 ug/L 75%



### Conclusion for Benzo(a)pyrene

A lthough the laboratory passing rate s f or 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 μg/L . I t 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 59 

### Bromate

Results of the Methods Comp arison

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 -1 ]). The MDL s /DL s for bromate by EPA Methods 317.0 , 321.8 and 326 .0 are
lower than those for EPA M ethod 300.1, suggesting that laboratory perfo rmance 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 ar e 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 = 0.010 mg/L Current PQL = 0.01 mg/L D L = N/A Acceptance Criteria = Mean + 2 Std Dev 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL mg/L

300.1 IC 0.00128

- 0.00144

317.0 IC with postcolumn reagent 0.00012

– 0.00098

321.8 IC/ICP/MS 0.00 03 (DL)

326.0 I C with suppressor acidified postcolumn reagent 0.00017

– 0.0012 (DL)

Notes: EPA has not provided a regulatory DL for bromate in the CFR

. A cceptance C riteria for disinfection byproducts are listed at 40 CFR 141. 131(b )( 2 )( i i). As of April 1, 2007, the
A cc eptance C riteri a for bromate were changed to + 30 % (71 FR 388 1/4/2006).



### Results of the PQL Analysis

T he current PQL for bromate 10 μ g/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 μg/L . One of the 60 spike values in the Six

- Year 2/ERA data set is below the PQL. T hree of the Six

- Year 1 concentrations and two of the Six

- Year 2/ERA concentration s have passing rates of less than 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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October 2009

Page 60 

### Exhibit 41: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Bromate

Conclusion for Bromate

A lthough 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 μg/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 c ould suggest possible reduction of the PQL

. 0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= Mean + 2 SD

Current PQL = 10 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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October 2009

Page 61 

### Dichloromethane (Methylene chloride)

Results of the Methods Comparison

Exhibit 42 summarizes the MDLs for dichloromethane as documented in EPA-developed analytica l 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 Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.01

- 0.02

524.2 CCGC/MS 0.03

- 0.09

Note s : 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 dichloromethane is 5 μg/L . The Six

- Year 1 and Six

- Ye ar 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 μ g/L and + 20% at or above 10 μ 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 μ g/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 62 

### Exhibit 43: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Dichloromethane

Conclusion for Dichloromethane

A lthough most laboratory passing rates for both the Six- Year 1and Six

- Year 2/ERA data sets are high ( well above 75 %) in the vicinity of the current PQL of 5 μg/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 an alytical performance in the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-2007. 0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Di(2

- ethylhexyl)phthalate (DEHP)

Results of the Methods Comparison

Exhib it 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 Technique MDL μg/L

506 LLE or LSE and GC/PID 2.25

525.2 L SE and CCGC/MS 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 PQL Analysis

The current PQL for DEHP is 6 μ g/L

. The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 45). The Six

- Year 1 P E data for DEHP were regressed as part of the March 2003 report. Two of the 18 spike values i n the Six- Year 1 data set are below the

current PQL of 6 μ 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%. T hree of the Six

- Year
2/ERA passing rates are less than or equal to 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Exhibit 45: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Di(2

- ethylhexyl)phthalate

ERA Data PQL Six-Year 1 Data 75% Passing Rate 0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35 40 45 50
True Value (ug/L)% Laboratories Passing

Acceptance Criteria

= Mean + 2 SD

Current PQL = 6 ug/L 75%



### Conclusion for Di(2 -e thylhexyl)phthalate

Given the low laboratory passing rates below and in the vicinity of the PQL of 6 μg/L for
the Six

- Year 1 data set and the lack of data below the PQL and the variability of the Six

- Year 2/ERA data set, it is 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Ethylene dibromide (EDB )

Results of the Methods Comparison

Exhibit 46 summarizes the MDLs for ethylene dibromide as documented in EPAdeveloped 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 Analysi s of Drinking Water

Method Technique MDL μg/L

504.1 ME and GC 0.01

551.1 LL E/GC w/ ECD 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 list ed at 40 CFR 141.24(h)(19)(i)(B)

.



### Results of the PQL Analysis

The current PQL for EDB is 0.05 μ g /L

. T he Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 47). The Six

- Year 1 P E 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 μ g/L

. Nearly a ll of the passing rates in the Six

- Year
1 and Six

- Year 2/ERA data set are above 75% (with the exception of three pass ing rates equal to 75%).EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Exhibit 47: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Ethylene Dibromide

Conclusion for Ethylene Dibromide

Although most passing rate of laboratories for both Six- Year 2/ERA and Si x- Year 1 data sets are high ( > 75%), it may not be appropriate to recommend lowering of the PQL due to the
l ack of data below or in the vicinity of the current PQL of 0.05 μg/L . The variability in the passing rates for both data sets further supports this recommendation. No new or r evised 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. 0 10 20 30 40 50 60 70 80 90 100

0.0 0.5 1.0 1.5 2.0 2.5
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 40%

Current PQL = 0.05 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Pentachlorophenol

Results of the Methods Comparison

Exhibit 48 summarizes the MDLs for pentachlorophenol as documented in EPAdeveloped 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-1). 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 -1 ). 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 Technique MDL μg/ L

515.1 GC/ECD 0.032

515.2 LSE and GC/ECD 0.16

515.3 LLED and GC/ELCD 0.021

- 0.085

515.4 LLMED and GC/ECD 0.014

– 0.084

525.2 LSE and CCGC/MS 0.72 - 1.0

555 HP LC/PDAUVD 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 PQL Analysis

The current PQL for pentachlorophenol is 1 μ g/L

. The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 49). The Six

- Year 1 P E 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 μ g/L . None of the Six

- Year
2/ERA data are below the current PQL. Passing rates for both data sets are highly variable.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Exhibit 49: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – P entachlorophenol

0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70 80 90 100
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 50%

Current PQL = 1 ug/L 75%



### Conclusion for Pentachlorophenol

Given the limited data bel ow the PQL of 1 μg/L (only one Six- Y ear 1 datum just below the PQL ) and the high variability in the passing rates in the vicinity of the PQL for both the SixYear 1 an d the Six- Year 2/ERA data sets, it may not be appropriate to recommend lowering of the PQ L. 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Polychlorinatedbiphenyls (PCBs) as Decachlorobiphenyl (DCBP)

R esults of the Methods Comparison

Ex hibits 50 and 51 summarize the MD Ls for polychlorinatedbiphenyls as documented in
EPA -developed analytical methods. Note that the PE/ PT data and the MCL for PCBs are based

on P CBs 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 compli ance 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.

Exhib it 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 = + 100% 

### EPA Methods Approved for the Analysis of Drin king Water

Method Technique MDL μg/L

508A Perchlorination/GC (2

- Chlorobiphenyl as source) 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 141.24(h)(19)(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 = + 100% 

### EPA Methods Approved for the Analysis of Drinking Water

Met hod Technique MDL μg/L

505 ME and GC 0.08 - 15.0

508 GC/ ECD No MDLs

508.1 LSE a nd ECGC 0.012

- 0.044

525.2 LSE and CCGC/MS 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 141.24(h)(19)(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 ).EPA

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### Results of the PQL Analysis

The current PQL for PCBs is 0.5 μ g /L

. T he Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 52). The Six

- Year 1 P E data for PCBs were evaluated but were

not r egressed 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 μ g/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.

Exhibit 52: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – PCBs

0 10 20 30 40 50 60 70 80 90 100

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 100%

Current PQL = 0.5 ug/L 75%



### Conclusion for Polychlorinatedbiphenyls

Although the Six- Year 2/ERA laboratory passing rates are high (well above 75 %), g iven
the low labor atory passing rates and decreasing trend in laboratory passing rates below and in the vicinity of the PQL of 0.5 μg/L for the Six- Y ear 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### 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 Technique MDL mg/L

200.8 IC P/MS 0.00001

- 0.0003

200.9 GFAA 0.0007 Notes: Regulatory DLs for in organic compounds are listed at 40 CFR 141.2 3 ( a )( 4 ) (i)

. Acceptance Criteria for in organic compounds are listed at 40 CFR 141.2 3 ( k )( 3 )( i i).



### Results of the PQL Analysis

The current P QL 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 a ll 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Exhibit 54: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Thallium

0 10 20 30 40 50 60 70 80 90 100

0.00 0.01 0.01 0.02 0.02 0.03 0.03 0.04 0.04
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 30%

Current PQL = 0.002 mg/L 75%



### 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 low er laboratory passing rates in the vicinity of the PQL for the Six- Year 2/ERA data set, it may not be appropriate to recommen d 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### 6.2 Analytes with Maximum Co ntaminant Level (MCL) G reater Than the Current PQL and T hus it is Technically F easible to R educe 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 anal ytes, 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 an alytes 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 PQ L A ssessment Supports Reduction of the C urrent PQL

Of the 41 analytes mentioned above, 11 analytes have an existing PQL that i s 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 -1). 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 = + 15% 

### EPA Methods App roved for the Analysis of Drinking Water

Method Technique MDL mg/L

200.7 ICP

- AES 0. 001

200.8 ICP /MS 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 li sted at 40 CFR 141.23(k)(3)(ii).



### Results of the PQL 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 b arium 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 theEPA

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### exception of one spike value in the Six- Year 1 data, all of the passing rates exce ed 75%. Both
the Six -Year 1 and ERA regression lines are well above 75%.

E xhibit 56: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Barium

0 10 20 30 40 50 60 70 80 90 100

0.00 0.40 0.80 1.20 1.60 2.00 2.40 2.80
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 15%

Current PQL = 0.15 mg/L 75%



### Conclusion for Barium

The high laboratory passing rates (well above 7 5%) 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### 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 = 0.07 5 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 Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.01 - 0.04

524.2 CCG C/MS 0.03 - 0.04

Note s : 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-di chlorobenzene is 5 μ g/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 μg/L and + 20% at or

a bove 10 μg/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 μ g/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Exhibit 58: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – 1,4- Dichlorobenzene

0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for 1,4-Dichlorobenzene

T he high laborat ory passing rates (well above 75 %) at concentrations below the current PQL of 5 μg/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 analytica l 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

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### cis -1,2- Dichloroethylene

Results of the Methods Comparison

Exhibit 59 summarizes th e MDLs for cis -1,2- dichloroethylene as documented in EPA

developed analytical methods . No updated or new analytical methods have been approved for the analysis of cis -1,2-dichloroethylene in drinking water samples during the years 2000-2007.

Exhibit 59: Analytical Methods for cis -1,2- 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 Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.01 - 0.05

524.2 CCG C/MS 0.06 - 0.12

Note s : 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 ci s -1,2-dichloroethylene is 5 μ g/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. N ote that the acceptance
criteria are + 40% at spike concentrations below 10 μg/L and + 20% at or above 10 μ g/L ; hence
the data are regressed as two independent populations. No Six- Year 1 data are available below the current PQL of 5 μ 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%).EPA

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### Exhibit 60: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – cis -1,2- Dichloroethylene

Conclusion for cis -1,2-Dichloroethylene

T he hi gh laboratory passing rates (well above 75 %) at concentrations below the current PQL of 5 μg/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 i mprove analytical performance in the vicinity of the current PQL (and hence suggest possible reduction of the PQL) have been approved from 2000-2007. 0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35 40 45 50
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20%

Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%EPA

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### 1,1- Dichloroethylene

Results of the Methods Comparison

Exhibit 61 summarize s the MDLs for 1,1-dichloroethylene as documented in EPAdeveloped 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 : A nalytical 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 Technique MDL μg/L

502.2 CCGC with PID / ELCD 0.04

- 0.1

524.2 CCGC/MS 0.05

- 0.12

Note s : 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 1,1-dichloroethylene is 5 μ g/L

. The Six

- Year 1 and Six

- Y ear 2/ERA data sets are regressed separately (see Exhibit 62). The Six

- Year 1 P E data for 1,1- dichloroethylene were evaluated but were not regressed as part of the Ma rch 2003 report. N ote that the acceptance criteria are + 40% at spike concentrations below 10 μg/L and + 20% at or
above 10 μ g /L ; he nce the data are regressed as two independent populations. No Six- Year 1 data are available below the current PQL of 5 μ g/ L . Ten of the 60 spike values in the Six

- Y ear 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 μ g/L ) ha s 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) tha t 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 genera lly high laborat ory performance

.EPA

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### Exhibit 62: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – 1,1- Dichloroethylen e

Conclusion for 1,1-Dichloroethylene

T he high laboratory passing rates ( well above 75%) at concentrations below the current PQL of 5 μg/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. 0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 81 

### 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 Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.01 - 0.04

524.2 CCG C/MS 0.03 - 0.06

Note s : 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 μ g/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 2 003 report. N ote that the acceptance criteria are + 40% at spike

c oncentrations below 10 μg/L and + 20% at or above 10 μ g/L ; hence the data are regressed as two independent populations. No Six- Year 1 data are available below the current PQL of 5

μ g/L . Eighteen of the 60 spike values in the Six

- Year 2/ERA data are be low the current PQL. All of the passing rates are above 75% (with the exception of one passing rate equal to 75%).EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 82 

### Exhibit 6 4: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Eth ylbenzene

100

0 10 20 30 40 50 60 70 80 90

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for Ethylbenzene

T he high laboratory passing rates ( well above 75%) at concentrations below the current PQL of 5 μg/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 perfo rmance 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 815 -B- 09

- 003
October 2009

Page 83 

### Monochlorobenzene (Chlorobenzene)

Results of the Methods Comparison

Exhibit 65 su mmarizes the MDLs for monochlorobenzene as documented in EPAdeveloped analytical methods . No updated or new analytical methods have been approved for the analysis of monochlorobenzene in drinking water sampl es 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 Technique MDL μg/L

502.2 CCGC with PID/EL CD 0.01

- 0.02

524.2 CCGC/MS 0.03 - 0.04

Note s : 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 An alysis

The current PQL for monochlorobenzene is 5 μ g/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. N ote that t he acceptance criteria are + 40% at spike concentrations below 10 μg/L and + 20% at or above 10

μ g/L ; hence the data are regressed as two independent populations. No Six- Year 1 data are available below the current PQL of 5 μ g/L . Three of the 60 spike val ues in the Six

- Year 2/ERA
data set are bel ow the current PQL. All of the passing rates are above 75%, and all four regression lines are well above 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 84 

### Exhibit 66: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Monochlorobenzene

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35 40 45 50
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for Monochlorobenzene

T he hi gh laboratory passing rates (well above 75 %) at concentrations below the current PQL of 5 μg/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 815 -B- 09

- 003
October 2009

Page 85 

### Nitrite (as N)

Results of the Methods Comparison

Exhibit 67 summarizes the MDLs for nitrite as documented in E PA

- 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 ; F ederal Register, Vol. 72, No. 47, p. 11200, March 12, 2007 ; see Exhibit A -1). The updates to methods are associated with administrative and technical changes or clarifications that ar e 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 = 1 mg/L Current PQL = 0.4 mg/L DL = 0 .004

- 0.103 mg/L Acceptance Criteria = + 15% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL mg/L

300.0 IC 0. 004

300.1 IC 0. 001

353.2 A uto Colorimetry No MDL
Notes: Regulatory DLs for inorganic compounds are listed a t 40 CFR 141.23(a)(4)(i). Acceptance Criteria for in organic compounds are listed at 40 CFR 141.23(k)(3)(ii).



### Results of the PQL 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 (se e 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 th e passing rates are above 75% and both regression lines are also well above 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 86 

### Exhibit 68: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Nitrite

Conclusion for Nitrite

T he high laborat ory passing rates (above 75%) at concentrations below the current PQL
of 5 μg/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

. 0 10 20 30 40 50 60 70 80 90 100

0.0 0.5 1.0 1.5 2.0 2.5
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 15%

Current PQL = 0.4 mg/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 87 

### Styrene

Results of the Methods Comparison

Exhibit 69 summarizes the MDLs for styrene as documented in EPA -developed analytical meth ods. No updated or new analytical methods have been approved for the analysis of styrene in drinking water samp les 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 Technique MDL μg/L

502.2 CCGC with PID/ELCD 0.01 - 0.1

524.2 CCG C/MS 0.04 - 0.06

Note s : 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 μ g/L

. The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed se parately (see Exhibit 70). The Six- Year 1 PE data for styrene were not evaluated as part of the March 2003 report. N ote that the acceptance criteria are + 40% at spike

c oncentrations below 10 μg/L and + 20% at or above 10 μ g/L ; hence the data are regress ed as two independent populations. No Six- Year 1 data are available below the current PQL of 5

μ 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 passi ng rate equal to 75%)

. Furthermore, the regression lines are well above 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 88 

### Exhibit 70: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Styrene

Conclusion for Styrene

T he high laborat ory passing rates (75 % or above) at concentrations below the current PQL of 5 μg/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. 0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 89 

### 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 dr inking water samp les 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 Wate r
Method Technique MDL μg/L

502.2 CCGC with PID/ELCD 0.01 - 0.02

524.2 CCG C/MS 0.08 - 0.11

Note s : 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 μ 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 regre ssed as part of the March 2003 report. N ote that the acceptance criteria are + 40%

a t spike concentrations below 10 μg/L and + 20% at or above 10 μ g/L ; hence the data are regressed as two independent populations. No Six- Year 1 data are available below the current PQL of 5 μ 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 90 

### Exhibit 72: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Toluene

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20%

Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for Toluene

The hi gh laboratory passing rates (well above 75 %) at concentrations below the current PQL of 5 μg/L for the Six -Year 2/ERA data set suggest that the PQL could be lower. Although
there are no Six

- Year 1 data bel ow 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 815 -B- 09

- 003
October 2009

Page 91 

### 1,2,4- Trichlorobenzene

Results of the Methods Comparison

Exhibit 73 summarizes the MDLs for 1,2,4-trichlorobenzen e 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 Technique MDL μg/L

502.2 CCGC with PID/ELCD 0.02 - 0.08

524.2 CCGC/M S 0.04 - 0.20

Note s : 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-tri chlorobenzene is 5 μ g/L

. The Six

- Year 1 and Six

- Y ear 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. N ote that the acceptance
crit eria are + 40% at spike concentrations below 10 μg/L and + 20% at or above 10 μ g/L ; hence
the data are regressed as two independent populations. No Six

- Year 1 data are available below the current PQL 5 μ g/L . Six of the 60 spike values in the Six

- Year 2/E RA data are bel ow 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 92 

### Exhibit 74: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – 1,2,4-
Trichlorobenzene

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for 1,2,4-Trichlorobenzene

T he high laboratory passing rates (>80%) at concentrations below the current PQL of 5 μg/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 815 -B- 09

- 003
October 2009

Page 93 

### 1,1,1-Trichloroethane

Results of the Methods Comparison

Exhibit 75 summarizes the MDLs for 1,1,1-trichloroethane as documented in EPAdeveloped 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 1,1,1- 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 Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.01

- 0. 03

524.2 CCGC/MS 0.04

- 0.08

551.1 LLE/GC w/ ECD 0.005

- 0.012

Note s : 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 1,1,1-t richloroethane is 5 μ g/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 regres sed as part of the March 2003 report. N ote that the acceptance criteria are + 40% at spike concentrations below 10 μg/L and + 20% at or

a bove 10 μ g/L ; hence the data are regressed as two independent populations. One of the 17 spike values from the Six- Ye ar 1 data is below the current PQL of 5 μ g/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 94 

### Exhibit 76: Evaluation of Six-Year 1 and Six -Y ear 2/ERA PT Data – 1,1,1- Trichloroethane

0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16 18 20
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for 1,1,1-Trichloroethane

T he high laboratory passing rates (generally >90%) at concentrations below the current PQL of 5 μg/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 r evised 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 815 -B- 09

- 003
October 2009

Page 95 

### 6.2.2 PQL A ssessment May Support Reduction of the C urrent PQL

Of the 41 analytes mentioned in Section 6.2, s ix analytes have an existing PQL that is
less than the MCL and their PE/ PT data suggest that the PQL could possibly be lower

.

A trazine

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 ( Federa l Register , Vol. 67, No. 209, p. 65888, October 29, 2002 ; see Exhibit A -1). Since the method is proprietary, t he 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 meth od performance.” Thus, it is uncertain whether new MDLs may be lower than those for other
methods.

Ex hibit 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 Met hods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

505 ME and GC 2.4

507 GC /N

- PD 0.015

508.1 L SE and ECGC 0.003

525.2 L SE and CCGC/MS 0.065

- 0.081

551.1 LLE/GC w/ ECD 0.082

- 0.121 Notes: Regulatory DLs for synthetic organi c 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 atrazine is 1 μ g/L

. The Six

- Year 1 and Six

- Year 2/ERA data se ts 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 μ g/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 96 

### Exhibit 78: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Atrazine

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 45%

Current PQL = 1 ug/L 75%



### Conclusion for Atrazine

Given the limited data below the current PQL of 1 μg/L but generally high laborat ory 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 vicin ity 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 DL s 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 97 

### 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-1). The range of DLs /MDLs for carbofuran by EPA Method 531.2 is appro ximately one order of magnitude less than the MDL from EPA M ethod 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 Cur rent PQL = 0.007 mg/L DL = 0.0009 mg/L Acceptance Criteria = + 45% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

531.1 DAI/HPLC w/ Der. 0.52

531.2 DA I/HPLC w/ Der. 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 PQL Analysis

The current PQL for carbofuran is 7 μ g/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 μ g/L. N o 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 98 

### Exhibit 80: Evaluation of Six- Ye ar 1 and Six

- Year 2/ERA PT Data – Carbofuran

0 10 20 30 40 50 60 70 80 90 100

0 30 60 90 120 150
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 45%

Current PQL = 7 ug/L 75%



### Conclusion for Carbofuran

Given the limited data below the current PQL of 7 μg/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 rang ing from less than 70% to 100% which may not support the Six- Year 1 data conclusio n that the PQL could be lower. The range
of DLs/MDLs for carbo furan 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 99 

### trans-1,2- Dichloroethylene

Results of the Methods Comparison

Exhibit 81 summarizes the MDLs for trans -1,2-dichloroethylene as documented in EPAdeveloped analytical methods . No updated or new analytical methods have been approved for the analysis of trans -1,2-dichloroethylene in drinking water samples during the years 2000-2007.

Exhibit 81: Analytical Methods for trans -1,2- 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 Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.03

- 0.06

524.2 CCGC/MS 0. 03 - 0.06

Note s : 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 trans -1,2 -dichloroethylene is 5 μ g/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. N ote that the acceptance
criteria are + 40% at spike concentrations below 10 μg/L and + 20% at or above 10 μ g/L ; hence
the data are regressed as two independent populations. No Six- Year 1 data are available below the current PQL of 5 μ g/L

. Three of the 60 spike values in the Six

- Year 2/ERA d ata set are below the current PQL. All but two of the passing rates are above 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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### Exhibit 82: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – trans -1,2- Dichloroethylene

Conclusion for trans -1,2-Dichloroethylene

Given the limited data below the current PQL of 5 μg/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 dat a 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 SixYear 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. 0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35 40 45 50
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Hexachlorocyclopentadiene

Results of the Methods Comparison

Exhibit 83 summarizes the MDLs for hexachlorocyclopentadiene as documented in EPAdeveloped analytical methods . No updated or new analytical methods have been approved for the analysis of hexac hlorocyclopentadiene 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 = 0.0001 mg/L Acceptance Criteria = Mean + 2 Std Dev 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

505 ME and GC 0.13

508 GC/ECD No MDL

508.1 LSE and ECGC 0.004

525.2 L SE and CCGC/MS 0.072 - 0.16

551.1 L LE/GC w/ ECD 0.016

- 0.018

Note s : 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 hexachlorocyclopentadiene is 1 μ g/L

. The Six

- Year 1 and S ix

- Year 2/ERA data sets are regressed separately (see Exhibit 84). The Six

- Year 1 P E 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 belo w the current PQL of 1 μ g/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 severa l passing rates below 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Exhibit 84: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Hexachlorocyclopentadiene

Conclusion for Hexachlorocyclopentadiene

G iven the generally high laboratory passing rates ( all but one well above 75%) below and in the vicinity of the current PQL of 1 μg/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 ra nging 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. 0 10 20 30 40 50 60 70 80 90 100

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate

Acceptance Criteria

= Mean + 2 SD

Current PQL = 1 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 103 

### 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 of Drinking Water

Method Technique MDL μg/L

505 ME and GC 0.96

508 G C/ECD 0.022

508.1 L SE and ECGC 0.003

525.2 LSE and CCGC/MS 0.033

- 0.13

551.1 LLE/GC w/ ECD 0.008

- 0.026

Note s : 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

T he current PQL for methoxychlor is 10 μ g/L

. The Six

- Yea r 1 and Six- Year 2/ERA data sets are regressed separately (see Exhibit 86). The Six

- Year 1 P E 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 μ g/L

. All of the p assing
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/E RA regression line predicts a decrease in passing rates with an increase in spike
values

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### Exhibit 86: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Methoxychlor

0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70 80 90 100
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 45%

Current PQL = 10 ug/L 75%



### Conclusion for Methoxychlor

G iven the generally high laboratory passing rates (well above 75%) below and in the vicinity of the current PQL of 10 μg/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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### 2-(2,4,5-Trichlorophenoxy)propano ic 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 t he analysis of 2,4,5-TP in drinking water samples during the years 2000-2007 ( see Exhibit A-1). 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 -1). The MDL for 2,4,5- TP by EPA M ethod 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 = 0.0002 mg/L Acceptance Criteria = + 50% 

### EPA Methods Approved for the Analysis of Dri nking Water

Method Technique MDL μg/L

515.1 GC/ECD 0.21

515.2 LSE and GC/ECD 0.16

515.3 LLE D and GC/ELCD 0.072 - 0.14

515.4 LLM ED and GC/ECD 0.018

– 0.033

555 HPLC/PDAUVD 0.37

- 1.8

Note s : Regulatory DLs for synthetic organic compounds are listed a t 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 2,4,5- TP is 5 μ g/L

. The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separat ely (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 P E data are less than the current PQL of 5 μ g/L

. No Six

- Year 2/ERA data are below the current PQL

. Whi le the passing rates for both data sets are fairly variable, a ll 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 an d Six

- Year 2/ERA regression
lines are above 75%

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 106 

### Exhibit 88: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – 2,4,5-TP (Silvex)

0 10 20 30 40 50 60 70 80 90 100

0 30 60 90 120 150
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 50%

Current PQL = 5 ug/L 75%



### Conclusion for 2,4,5- TP

Given the limited data below the current PQL of 5 μg/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 som e variability, with laboratory passing rates inthe vicinity of the PQL ranging from less than 70% to 100%; which may not support the SixYear 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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### 6.2.3 PQL A ssessment Does Not Support Reduction of the Current PQL or Da ta are
I nsufficient to Reach a C onclusion

O f 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.

A rsenic

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
drin king water samples during the years 2000-2007 (se e Exhibit A -1). 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 propri etary 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

Metho d Technique MDL mg/L

200.7 ICP

- AES 0.008

200.8 IC P/MS 0.0001

- 0.0014

200.9 GFAA 0.0005 Notes: Regulatory DLs for in organic compounds are listed at 40 CFR 141.2 3(a )( 4) (i)

. Acceptance Criteria for inorganic compounds are listed at 40 CFR 141.2 3 ( k )( 3 )( i i).



### Results of the PQL 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 o f 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 108 

### Exhibit 90: Evaluation of Six-Year 1 and Six

- Year 2/E RA PT Data – Arsenic

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 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. 0 10 20 30 40 50 60 70 80 90 100

0.00 0.03 0.06 0.09 0.12 0.15
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 30%

Current PQL = 0.003 mg/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 109 

### 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 -1). 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 = + 15% 

### EPA Methods App roved for the Analysis of Drinking Water

Method Technique MDL mg/L

200.7 I CP

- AES 0.0003

200.8 IC P/MS 0.00002

- 0.0003

200.9 GFAA 0.00002 Notes: Regulatory DLs for in organic compounds are listed at 40 CFR 141.2 3 ( a )( 4 ) (i)

. Acceptance Criteria for inorg anic compounds are listed at 40 CFR 141.2 3 ( k )( 3 )( i i).



### 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 P E 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

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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October 2009

Page 110 

### Exhibit 92: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Beryllium

0 10 20 30 40 50 60 70 80 90 100

0.000 0.005 0.010 0.015 0.020 0.025
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 15%

Current PQL = 0.001 mg/L 75%



### Conclusion for Beryllium

Given the relative lack of data and the downward trend in laboratory passing rates below
the current P QL 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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October 2009

Page 111 

### 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 analys is of cadmium in drinking water samples during the years 2000-2007 ( see Exhibit A -1). 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 Dr inking Water

Method Technique MDL mg/L

200.7 ICP

- AES 0.001

200.8 IC P/MS 0.00003

- 0.0005

200.9 GFAA 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 PQL 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 P E 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 112 

### Exhibit 94: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data – Cadmium

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. 0 10 20 30 40 50 60 70 80 90 100

0.000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 20%

Current PQL = 0.002 mg/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 113 

### 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 (s ee Exhibit A -1). 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 no t 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 = + 15% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL mg/ L

200.7 ICP

- AES 0. 004

200.8 ICP /MS 0.00008

- 0.0009

200.9 GFAA 0.0001 Notes: Regulatory DLs for in organic compounds are listed at 40 CFR 141.2 3 ( a )( 4 ) (i)

. Acceptance Criteria for inorganic compounds are listed at 40 CFR 141.2 3 ( k )( 3 )( i i).



### Results of the PQL 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 P E data for chromium were evaluated but not regressed in the March 2003 report. None of t he 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 114 

### Exhibit 96: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Dat a – Chromium

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. 0 10 20 30 40 50 60 70 80 90 100

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 15%

Current PQL = 0.01 mg/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 115 

### 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 -1). 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 = + 10% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL mg/L

200.7 I CP

- AES 0.003

200.8 IC P/MS 0. 00001

- 0.0005

200.9 GFAA 0.0007

Notes: EPA has not provided a regulatory DL for copper in the CFR. The Acceptance Criteri a for copper are lis ted at 40 CFR 141. 89 ( a )( 1 )( i i) (B)

.



### Results of the PQL Analysis

The current PQL for copper is 0.05 m g/L . T he 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 . T he single concentration value less than the PQL corresponds to a passing rate of less than 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 116 

### Exhibit 98: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Copper

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. 0 10 20 30 40 50 60 70 80 90 100

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 10%

Current PQL

= 0.05 mg/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 117 

### 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 -1). 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 new ly -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 Technique MDL mg/L

335.4 Semi

- Auto Colorimetry No MDL
Notes: Regulatory DLs for in organic compounds are listed at 40 CFR 141.2 3 ( a )( 4 ) (i)

. Acceptance Criteria for in organic compounds are listed at 40 CFR 141.2 3 ( k )( 3 )( i i).



### Results of the PQL 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 20 03 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 118 

### Exhibit 100: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Cyanide

0 10 20 30 40 50 60 70 80 90 100

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 25%

Current PQL = 0.1 mg/L 75%



### 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 lowe ring 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 119 

### Dalapon

Results of the Methods Comparison

Exhibit 101 summarizes the MDLs for dalapon as documented i n 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 , Vo l. 67, No. 209, p. 65888, October 29, 2002, Federal Register, Vol. 72, No. 47, p. 11200, March 12, 2007 ; see Exhibit A

1). The range s 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 De v 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

515.1 GC/ECD 1.3

515.3 LLE D and GC/ELCD 0.53 - 0.97

515.4 LLM ED and GC/ECD 0.054

– 0.074

552.1 I- ELSE/GC w/ ECD 0.32

552.2 LLED/GC w/ ECD 0.119

552.3 LLMED/GC w/ EC D 0.024 - 0.14

Note s : 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 dalapon is 10 μ g/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
evalua ted 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%

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 120 

### Exhibit 102 : Ev aluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Dalapon

Conc lusion for Dalapon

A lthough 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 μg/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. Thi s may lead to an overall improvement in analytical performance in the vicinity of the current PQL and could suggest possible reduction of the PQL. 0 10 20 30 40 50 60 70 80 90 100

0 30 60 90 120 150
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= Mean + 2 SD

Current PQL = 10 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 121 

### 1,2- Dichlorobenzene

Results of the Methods Comparison

Exhibit 103 summarizes t he MDLs for 1,2-dichlorobenzene as documented in EPAdeveloped 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 : Analy tical 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 Technique MDL μg/L

502.2 CCGC with PID/ELCD 0. 02 - 0.05

524.2 CCG C/MS 0.03 - 0.05

Note s : 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 Analysi s

The current PQL for 1,2-di chlorobenzene is 5 μ g/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. N ote that the acceptance criteria

are + 40% at spike concentrations below 10 μ g/L and + 20% at or above 10 μ g/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 μ g/L

. However, all of the passing rates for the two data sets
are well above 75%

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 122 

### Exhibit 104: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – 1,2- Dichlorobenzene

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%



### Conclusion for 1,2-Dichlorobenzene

A lthough 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 μg/L for both data sets, it may not be appropriate to recommend lowering of the PQL. No
new or revised m ethods 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 815 -B- 09

- 003
October 2009

Page 123 

### 2,4-D ichlorophenoxyacetic acid (2,4- D)

Results of the Methods Comparison

E xhibit 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 samp les during the years 2000-2007 ( see Exhibit A -1). These updates are minor technical revisions that are not anticipated to improve analytical performance near the PQL

. In a ddition, a new method, EPA Method 515.4 was approved ( Federal Register , Vol. 67,

No . 209, p. 65888, October 29, 2002 ; see Exhibit A -1). The MDL for 2,4- D by EPA M ethod
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 = 0.0001 mg/L Acceptance Criteria = + 50% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

515.1 GC/ECD 0.078

515.2 L SE and GC/ECD 0.28

515.3 LLE D and GC/ELCD 0.35 - 0.36

515.4 LLM ED and GC/ECD 0.055

- 0.066

555 HPLC/PDAUVD 0.34

- 1.3

Note s : Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18). Acceptance Criteria for synthetic or ganic compounds are listed at 40 CFR 141.24(h)(19)(i)(B).



### Results of the PQL Analysis

The current PQL for 2,4- D is 5 μ g/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 μ g/L

. Several passing rates are below
75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 124 

### Exhibit 106: Evaluation of Six- Year 1 and Six

- Year 2/ERA PT Data – 2,4-D

0 10 20 30 40 50 60 70 80 90 100

0 30 60 90 120 150
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 50 %

Current PQL = 5 ug/L 75%



### Conclusion for 2,4-D

G iven the variable laboratory passing rates for the Six

- Year 1 and Six

- Year 2/ERA data
sets and the lack of dat a below the current PQL of 5 μg/L for both data sets (with th e 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 achievab le 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 125 

### 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 W ater

Method Technique MDL μg/L

506 LLE or LSE and GC/PID 11.82

525.2 LSE and CCGC/MS 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 141.24(h)(19)(i)(B)

.



### Results of the PQL Analysis

The current PQL for DEHA is 6 μ g/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 μ 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%

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 126 

### Exhibit 108: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – DEHA

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35 40 45 50
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= Mean + 2 SD

Current PQL = 6 ug/L 75%



### Conclusion for DEHA

A lthough laboratory passing rates are high (well above 75% in the vicinity o f 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 μg/L for both the Six- Year 1 and Six

Year 2/ERA data sets, it may not be appropriate to reco mmend 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 127 

### Dinoseb

Re sults 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 -1).
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 mg/L Acceptance Criteria = Mean + 2 Std Dev 

### EPA Methods App roved for the Analysis of Drinking Water

Method Technique MDL μg/L

515.1 GC/ECD 0.33

515.2 LSE and GC/ECD 0.28

515.3 LLED and GC/ELCD 0.75 - 0.82

515.4 LLM ED and GC/ECD 0.081

– 0.166

555 HPLC/PDAUVD 0.26 - 1.5
Notes: Regulatory DLs for synthetic or ganic 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 dinoseb is 2 μ 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 μ 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 128 

### Exhibit 110: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Dino seb

Conclusion for Dinoseb

A lthough 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 μg/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

. 0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35 40 45 50
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= Mean + 2 SD

Current PQL = 2 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 129 

### 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 : Anal ytical 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 Technique MDL μg/L

549.2 LSE/HPLC w/ UVD 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 μ g/L

. The S ix

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 112). The Six

- Year 1 P E 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 P QL of 2 μ g/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 13 0 

### Exhibit 112: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Diquat

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 μg/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. 0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35 40 45
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= Mean + 2 SD

Current PQL = 4 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 131 

### Endothall

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 samp les 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 Technique MDL μg/L

548.1 I- EE/Methylate and GC/MS 0.7 - 1.79 Notes: Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18). Acceptance Criteria for synt hetic organic compounds are listed at 40 CFR 141.24(h)(19)(i)(B).



### Results of the PQL Analysis

The current PQL for endothall is 90 μ 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 fo r 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 th at 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 t he 0% passing rate near 220 ug/L from the Six

- Year 1 data was a study that consisted of only one laboratory.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 132 

### Exhibit 114: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Endothall

0 10 20 30 40 50 60 70 80 90 100

0 50 100 150 200 250 300 350 400 450 500
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= Mean + 2 SD

Current PQL = 90 ug/L 75%



### Conclusion for Endothall

A lthough 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 μg/L for both the Six- Year 1 and Six

Year 2/ERA data sets, it may not be appropriate to recommend low ering 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 133 

### Endrin

Results of th e 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 Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

505 ME and GC 0.063

50 8 G C/ECD 0.0062

508.1 L SE and ECGC 0.007

525.2 LSE and CCGC/MS 0.16

- 0.34

551.1 LLE/GC w/ ECD 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 μ g/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 evaluate d 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 μ g/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 134 

### E xhibit 116: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Endrin

0 10 20 30 40 50 60 70 80 90 100

0 1 2 3 4 5 6
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 30%

Current PQL = 0.1 ug/L 75%



### Conclusion for Endrin

Given the variable laboratory passing rates in the vicinity of the current PQL of 0.1 μg/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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 135 

### Fluoride

Results of the Methods Comparison

Exhibit 117 summarizes the MDLs for fluoride as documented in EPA- developed analytical methods. Updates to eleven me thods 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-1). T he updates are associated with administrative and technical changes o r clarifications that are not expected to improve analytical performance near the PQL . The updated methods are proprietary a nd 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 mg/L Current PQL = 0.5 mg/L DL = N /A Acceptance Criteria = + 10% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL mg/L

300.0 IC 0.01

300.1 IC 0.009

Notes: EPA has not provided a regulatory DL for fluoride in the CFR

. Acceptance Criteria for
in organic compounds are listed at 40 CFR 141.2 3 ( k )( 3 )( i i).



### 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 P E data for fluoride were evaluatedbut were not regressed as part of the March 2003 report. One of the 20 spike values in the SixYear 1 da ta 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%

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 136 

### Exhibit 118: Evaluation of Six -Year 1 and Six

- Year 2/ERA PT Data – Fluoride

0 10 20 30 40 50 60 70 80 90 100

0 1 2 3 4 5 6 7 8
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 10%

Current PQL = 0.5 mg/L 75%



### Conclusion for Fluoride

G iven 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

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 137 

### 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 = 0.0 6 mg/L DL = 0.006 mg/L Acceptance Criteria = Mean + 2 Std Dev 

### EPA Methods Approved for the Analysis of Drin king Water

Method Technique MDL μg/L

547 DAI/HPLC w/ Der. and FD 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 μ g/L

. The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 120). The Six

- Year 1 P E 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 μ g/L . All but one of the passing rates in the SixYear 1 data are above 75%; however, several passing rates in the Six

- Year 2/ERA data are less than or equal to 75%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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Page 138 

### Exhibit 120: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Glyphosate

0 10 20 30 40 50 60 70 80 90 100

0 100 200 300 400 500 600 700 800
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= Mean + 2 SD

Current PQL = 60 ug/L 75%



### Conclusion for Glyphosate

G iven 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 μg/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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 139 

### 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 -1). 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 a nd 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 Technique MDL mg/L

200.8 IC P/MS 0.00002

- 0.0006

200.9 GFAA 0.0007

Notes: The r egulatory DL for lead is listed at 40 CFR 141. 89 ( a )( 1 ) (iii)

. Note that the DL is referred to as the “m ethod detection limit” in the CFR. The Acceptance Criteri a for lead are lis ted at 40 CFR 141. 89 ( a )( 1 )( i i) (A)

.



### Results of the PQL Analysis

The current PQL for lead is 5 μ g/L

. The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Ex hibit 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 μg/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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 140 

### Exhibit 122: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Lead

Conclusion for Lead

G iven the relative lack of data and the downward trend in labor atory passing rates below the current PQL of 5 μg/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. 0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70 80 90 100
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 30%

Current PQL = 5 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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Page 141 

### 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 -1). These updates are associated with
administrative and techn ical changes or clarifications that are not expected to improve analytical performance near the PQL . The updated methods are proprietary a nd 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 -1). 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 Technique MDL mg/L

200.8 ICP/MS 0.0002

245.1 CVAA S No MDL

245.2 AC VT No MDL

245.7 C VAFS 0.0000018 Notes: Regulatory DLs for in organic compounds are listed at 40 CFR 141.2 3 ( a )( 4 ) (i)

. Acceptance Criteria for in organic compounds are listed at 40 CFR 141.2 3 ( k )( 3 )( i i).



### 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 Exh ibit 12 4). The Six

- Year 1 P E 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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Page 142 

### Exhibit 124: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Mer cury

0 10 20 30 40 50 60 70 80 90 100

0.000 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 30%

Current PQL = 0.0005 mg/L 75%



### 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 vi cinity of the current PQL and could suggest possible reduction of the PQL.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 143 

### Nitrate (as N)

Results of the Methods Comparison

Exhibit 125 summarizes the MDLs for nitrate as documented in EPA

- developed analytical
methods. Updates t o 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 ; F ederal Registe r, Vol. 72, No. 47, p. 11200, March 12, 2007 ; see Exhibit A -1). 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 proprieta ry a nd are not listed in Exhibit
125. In additio n, MDL data for nitrate by EPA M ethod 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 = 10 mg/L Current PQL = 0.4 mg/L DL = 0.01

- 1 mg/L Acceptance Criteria = + 10% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL mg/L

300.0 IC 0. 002

300.1 IC 0.008

353.2 Auto Colorimetry No MDL
Notes: Regulatory DLs for in organic compounds are listed at 40 CFR 141.2 3 ( a )( 4 ) (i)

. Acceptance Criteria for in organic compounds are listed at 40 CFR 141.2 3 ( k )( 3 )( i i).



### Results of the PQL 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 da ta 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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Page 144 

### Exhibit 126: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Nitrate

0 10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12 14 16
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 10%

Current PQL = 0.4 mg/L 75%



### 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 appropri ate 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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Page 145 

### 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-1). The range of DL s for oxamyl by EPA M ethod 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 Me thods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

531.1 DAI/HPLC w/ Der. 0.86

531.2 DA I/HPLC w/ Der. 0.044 - 0.065 (DL)

Note s : Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18). Acceptance Crit eria for synthetic organic compounds are listed at 40 CFR 141.24(h)(19)(i)(B).



### Results of the PQL Analysis

The current PQL for oxamyl is 20 μg/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 μg/L ; however, none of the Six

- Year 2/ERA data are below the current PQL. Passing rates, particula rly in the Six -Y ear 1 data, are highly variable.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 146 

### Exhibit 128: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Oxamyl

0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70 80
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= Mean + 2 SD

Current PQL = 20 ug/L 75%



### Conclusion for Oxamyl

Given the variable laboratory passing rates in the vicinity of the current PQL of 20 μg/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 low er 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

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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October 2009

Page 147 

### Picloram

Result s 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 Ex hibit A -1). 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 -1). The MDL for picloram by EPA M ethod 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 P icloram

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 Technique MDL μg/L

515.1 GC/ECD 0.15

515.2 L SE and GC/ECD 0.35

515.3 L LE D and GC/ELCD 0.47 - 1.0

515.4 LLM ED and GC/ECD 0.055

– 0.076

555 HPLC/PDAUVD Not
Recovered - 0.5

Note s : 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 picloram is 1 μ g/L

. The Six

- Year 1 and Six

- Year 2/ERA data sets are regressed separately (see Exhibit 130). The Six

- Year 1 P E 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 μ g/L . T he passing rate s begin to drop below 75% approaching the PQL

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 148 

### Exhibit 130: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data

– P icloram

0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70 80
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate

Acceptance Criteria

= Mean + 2 SD

Current PQL = 1 ug/L 75%



### 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 μg/L and the lack of data below the PQL for both data sets, it may not be appropriate

t o 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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October 2009

Page 149 

### Selenium

Results of the Methods Comparison

Exhibit 131 summarizes the MDL s 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 -1). These updates are
associated with administra tive 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 Technique MDL mg/L

200.8 ICP/MS 0.0005

- 0.0079

200.9 GFAA 0.0006 Notes: Regulatory DLs for in organic compounds are listed at 40 CFR 141.2 3 ( a )( 4 ) (i)

. Acceptance Criteria for in organi c compounds are listed at 40 CFR 141.2 3 ( k )( 3 )( i i).



### 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 wer e not

eva luated 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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October 2009

Page 150 

### Exhibit 132: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Selenium

0 10 20 30 40 50 60 70 80 90 100

0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10
True Value (mg/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate Acceptance Criteria

= + 20%

Current PQL = 0.01 mg/L 75%



### 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 rev ised 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

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October 2009

Page 151 

### 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 : Analytica l 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 Technique MDL μg/L

505 ME and GC 6.8

507 GC /N

- PD 0.0 14

508.1 L SE and ECGC 0.008

525.2 LSE and CCGC/MS 0.045

- 0.18

551.1 LLE/GC w/ ECD 0.121

- 0.187

Note s : Regulatory DLs for synthetic organic compounds are listed at 40 CFR 141.24(h)(18). Acceptance Criteria for synthetic organic compounds are listed a t 40 CFR 141.24(h)(19)(i)(B).



### Results of the PQL Analysis

The current PQL for simazine is 0.7 μ g/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
evalua ted in the March 2003 report. None of the Six

- Year 2/ERA data are below the current PQL of 0.7 μ 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. All of the passing r ates 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%.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 152 

### Exhibit 134: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Simazine

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35 40
True Value (ug/L)% Laboratories Passing

ERA Data PQL Six-Year 1 Data 75% Passing Rate

Acceptance Criteria

= Mean + 2 SD

Current PQL = 0.7 ug/L 75%



### Conclusion for Si mazine

A lthough 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 μg/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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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October 2009

Page 153 

### 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 = 10 mg/L Current PQL = 0.005 mg/L DL = 0.0005 mg/L Acceptance Criter ia = + 20% or 40% 

### EPA Methods Approved for the Analysis of Drinking Water

Method Technique MDL μg/L

502.2 CCGC with PID/ ELCD 0.01 - 0.02

524.2 CCG C/MS 0.03 - 0.13

Note s : 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 xylenes is 5 μ 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 μg/L and + 20% at or above 10 μ g/L ; hence the data are

regresse d as two independent populations. No Six- Year 1 data are available below the current PQL of 5 μ g/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 7 5%; however the passing rates for the Six

- Year 2/ERA data set are more variable.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 154 

### Exhibit 136: Evaluation of Six-Year 1 and Six

- Year 2/ERA PT Data – Xylenes

Conclusion for Xylenes

A lthough 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 μg/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. 0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35 40 45 50
True Value (ug/L)% Laboratories Passing

ERA Data Below 10 ug/L ERA Data At or Above 10 ug/L PQL Six-Year 1 Data Below 10 ug/L Six-Year 1 Data At or Above 10 ug/L 10 ug/L Acceptance Criteria Boundary 75% Passing Rate Acceptance Criteria

= + 20% Acceptance Criteria

= + 40%

Current PQL = 5 ug/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 155 

## 7.0 Summary

This document examines analytical method performan ce 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 concl usion 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 prom ulgation to those of the currently approved methods.

E xhibit 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 rec ently -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 μg/L ). Only the current evaluations of the Six- Year 1 and Six

- Year 2/ERA data are presented in this report.

T he overall assessmentdecision presented in the final column of Exhibit 137 consists of
the follo wing possible outcomes:

**•** 

### Regulated Contaminants with Existing PQL Lower than the MCL

- P QL 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 curren t 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

- P QL 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;EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page 156 **•** 

### 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 thi s, 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 (dio xin) could not be analyzed due to a lack of
PE/ PT data, and chlorite has no PQL), the qualitative recommendations for PQL assessment br eak 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 co nsidered 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
ins ufficient 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 c an 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, cis -1,2-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, trans -1,2-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
i nsufficient to reach a conclusion for 24 analytes : arsenic, beryllium, cadmium, chromium, copper, cyanide, dalapon, 1,2-dichlorobenzene, 2,4-dichlorophenoxyacetic

ac id, di(2-ethylhexyl)adipate, dinoseb, diquat, endothall, endrin, fluoride, glyphosate, lead, mercury, nitrate, oxamyl, picloram, selenium, simazine, and xylenes.EPA

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Page 157 

### Several factors often require that these assessments be made qualitatively rather than

qua ntitatively . The regression of PE/ PT data vs . passing rate can be affected by high passing

r ates 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 considere d 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 μg/L are often much higher than those at or above 10 μ g/ L

. Passing rates of less than 75% may occur above 10 μ g/L , while much higher passing rates are often
observed below 10 μ g/L

.

Ex hibits 137 and 138 summarize the qualitative assessment for potential PQL reduction
for the Six

- Year 1 and Six

- Year 2/ERA data sets individually and include a final qualitative
recommendation considering both datasets. These exhibits also include an indication of whether

new or updated analytical method s might be expected to improve analytical performance in the vicinity of the c urrent 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 cur rent PQL, and thus it is technically feasible to reduce an MCL . Analytical method performance assessment for the se 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 C urrent P QL, and thus the PQL is L imiting - 25 Analytes

Analyte C urrent PQL (mg/L) New or Updated
M ethods? PQL Assessment Results

Current
Eva l uation of

Six

- Year 1
Data Current
Evaluation of

Six

- Year 2 (ERA 1999

- 2004) Data Overall Qualitative
Recommendation

Alachlor 0.002 No D at a may support lower PQL No data < current PQL; passing rates high in vicinity of current PQL Reduction of current PQL may be suppor t ed

Antimony 0.006 Y es - not expected to impr ove analytical performance in vicinity of current PQL Data may support lower PQL No data < current PQL; passing rates high in vicinity of current PQL Slight reduction of current PQL may be s up ported

Benzene 0.005 No Dat a support lower PQL Data support
low er PQL R eduction of current PQL supportedEPA

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Page 158 Analyte C urrent PQL (mg/L) New or Updated
M ethods? PQL Assessment Results

Current
Ev a luation of

Six

- Year 1
Data Current
Evaluation of

Six

- Year 2 (ERA 1999

- 2004) Data Overall Qualitative
R eco mmendation

Benzo(a)pyrene 0. 000 2 No No data < current PQL No data < current PQL No change to current PQ L

B romate 0. 01 Y es – may improve analytical performance in vicinity of current PQL . New methods 317.0 and
326.0 have l ower MDLs. Data indicate no change to

current PQL Data indicate no change to

current PQL No change to current PQL

Carbon tetrachloride 0. 005 No D ata support lower PQL Data support lower PQL R eduction of current PQL supported

Chlordane 0. 002 No D ata suppo rt lower PQL No data < current PQL; passing rates generally high in vicinity of current PQL R educ tion of current PQL

s upported

1,2

- D ibromo -3-

c hloropropane (DBCP) 0.0002 No Data may support lower PQL Data may support lower PQL Slight reduction of current PQL may be supported

1,2

- D ichloroethane ( Ethylene dichloride) 0.005 No Data support lower PQL Data support lower PQL R eduction of current PQL supported

Dichloromethane ( M ethylene Chloride) 0.005 No No data < current PQL No data < current PQL No change t o c urrent PQL

1,2

- D ichloropropane 0. 005 No No data < PQL; passing rates high in vicinity of current PQL Data support
l ow er PQL R eduction of current PQL supported

Di(2

- et hylhexyl) phthalate ( DEHP) 0.006 No Data indicate no change to

current PQL No data < current PQL No change to current PQ L

E thylene Dibromide ( ED B) 0.00005 No No data < current PQL No data < current PQL No change to current PQ L

H eptachlor 0. 000 4 No Data support lower PQL No data < current PQL; passing rates
variable in vicinity of

current PQL Reduction of current PQL may
be s uppor ted

Heptachlor epoxide 0. 000 2 No Data support lower PQL No data < current PQL; passing rates
variable in vicinity of current PQL Reduction of current PQL may
be s uppor ted

Hexachlorobenzene 0.001 No D ata support lower PQL Data support lower PQL R eduction of current PQL supported

Lindane 0.000 2 No Data may support lower PQL No data < current PQL; passing rates high in vicinity of current PQL Reduction of current PQL may
be s uppor tedEPA

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- Year Review EPA 815 -B- 09

- 003
October 2009

Page 159 Analyte C urrent PQL (mg/L) New or Updated
M ethods? PQL Assessment Results

Current
Ev a luation of

Six

- Year 1
Data Current
Evaluation of

Six

- Year 2 (ERA 1999

- 2004) Data Overall Qualitative
R eco mmendation

Pentachlorophenol 0. 001 Yes

- may improve analytical performance in vicinity of current PQL . New method 515.4 has capability of a lower MDL. Data indicate no

c hange t o current PQL No data < current PQL No change to current PQ L

PC Bs as DCBP 0. 000 5 No Data indicate no change to

current PQL No data < current PQL No change to current PQ L

T etrachloroethylene 0. 005 No N o data < current PQL; passing rates high in vicinity of current PQL Data support
l ow er PQL R eduction of current PQL supported

Thallium 0.002 No D ata may support lower PQL No data < current PQL No change to current PQ L

T oxaphene 0. 003 No D ata support lower PQL No data < current PQL; passing rates
variable in vicinity of current PQL Reduction of current PQL may
be s uppor ted

1,1,2

- T richloroethane 0. 005 No No data < current PQL; passing rates high in vicinity of current PQL Data support
l ow er PQL R eduction of current PQL supported

Trichloroethylene 0. 005 No N o data < current PQL; passing rates high in vicinity of current PQL Data support
l ow er PQL R eduction of current PQL

s upported

Vinyl chloride 0. 002 No N o data < current PQL; passing rates high in vicinity of current PQL Data may

s uppor t lower PQL Reduction of current PQL may be supportedEPA

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Page 160 

### Exhibit 138 : Second Six

- Year Review Analytical Feasibility Assessment Summary Analytes with MCL Gr eater than the Current PQL and T hus it is Technically Feasible to
R educe the MCL - 41 Analytes

Analyte C urrent PQL (mg/L) New or Updated
M ethods? PQL Assessment Results

Current
Ev a luation of

Six

- Year 1
Data Current
Evaluation of

Si x- Year 2 (ERA 1999

- 2004) Data Overall Qualitative Recommendation

Arsenic 0.003 Y es - not expected to improve analytical performance in vicinity of current PQL Data indicate no change to current PQL No data < current PQL N o c hange to current PQ L

Atrazine 0. 001 Yes

– Effect on performance unknown. DL from
new method
needed to assess effect on analytical performance in vicinity of current PQL Data may

s uppor t lower PQL No data < current PQL; passing rates
variable in vicinity of current PQL R educ tion of current PQL may
be s upported

Barium 0.15 Y es - not expected to improve analytical performance in vicinity of current PQL Data support slightly lower PQL No data < current PQL; passing rates high in vicinity of current PQL S l ight reduction of current PQL

s upported

Beryllium 0. 001 Y es - not expected to improve analytical performance in vicinity of current PQL Data indicate no change to

current PQL No data < current PQL N o c hange to current PQ L

Cadmium 0.002 Yes

- not expected to improve analytical performance in vicinity of current PQL No data < current PQL No data < current PQL No c hange to current PQ L

Carbofuran 0. 007 Yes

- may improve analytical performance in vicinity of current PQL . New method
531.2 has lower
MDL. Data support
l ow er PQL No data <

curren t PQL; passing rates
variable in vicinity of current PQL R educ tion of current PQL may
be s upported

Chromium 0. 01 Yes

- not expected to improve analytical performance in vicinity of current PQL No data < current PQL No data < current PQL N o c hange to curre nt PQL

Copper 0. 05 Yes

- not expected to improve analytical performance in vicinity of current PQL Data indicate no

c hange t o current PQL No data < current PQL N o c hange to current PQ LEPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page 161 Analyte C urrent PQL (mg/L) New or Updated
M ethods? PQL Assessment Results

Current
Eva l uation of

Six

- Year 1
Data Current
Evaluation of

Si x- Year 2 (ERA 1999

- 2004) Data Overall Qualitative
Reco m mendation

Cyanide (as free cyanide) 0.1 Y es – effect on performance
unknown. DLs from new method(s)
needed to assess effect on analytical performance in vicinity of current PQL No data <

current PQL No data < current PQL N o change to current PQ L

D alapon 0.01 Y es – may improve analytical performance in vicinity of current PQL . MDL from
new methods 515.4 and 552.3 are lower than previous MDLs Cannot
deter m ine passing rates for data < current PQL No data < current PQL No change to current PQ L

1, 2

- Dichlorobenzene (o

- D i chlorobenzene) 0.005 No No data < current PQL No data < current P QL No change to current PQ L

1, 4

- Dichlorobenzene (p

- D i chlorobenzene) 0.005 No Data support lower PQL Data support lower PQL R eduction of current PQL supported

1,1

- Dichloroethylene 0. 005 No N o data < current PQL; passing rates high in vicinity of curren t PQL Data support
low er PQL R eduction of current PQL supported

cis

- 1,2

- di chloroethylene 0. 005 No No data < current PQL; passing rates high in vicinity of current PQL Data support
low er PQL R eduction of current PQL supported

trans

- 1,2

- D i chloroethylene 0.005 No No data < current PQL; passing rates high in vicinity of current PQL Data may

suppor t lower PQL; passing rates generally high in vicinity of current PQL R eduction of current PQL may be supported

2,4

- Dichlorophenoxy

ac et ic acid (2,4

- D) 0.005 Yes

- m ay improve analytical performance in vicinity of current PQL . New method
515.4 has lower
MDL. Data indicate no change t o

c urrent PQL No data < current PQL N o change to current PQ L

Di (2

- ethylhexyl) adipate ( D EHA) 0.006 No Cannot
deter m ine passing rate for
data < current PQL No data < current PQL N o change to current PQ L

D inoseb 0.002 Yes

- may improve analytical performance in vicinity of current PQL . New method
515.4 has lower
MDL. No data < current PQL No data < current PQL N o change to current PQ LEPA

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Page 162 Analyte C urrent PQL (mg/L) New or Updated
M ethods? PQL Assessment Results

Current
Ev a luation of

Six

- Year 1
Data Current
Evaluation of

Si x- Year 2 (ERA 1999

- 2004) Data Overall Qualitative
R eco mmendation

Di quat 0. 004 No N o data < current PQL No data < current PQL N o c hange to current PQ L

Endothall 0.09 No C annot det er mine passing rate for
data < current PQL No data < current PQL No c hange to current PQ L

Endrin 0. 000 1 No No data < current PQL No data < current PQ L N o c hange to current PQ L

Ethylbenzene 0.005 No N o data < current PQL; passing rates high in vicinity of current PQL Data support
l ow er PQL R eduction of current PQL supported

Fluoride 0. 5 Yes – may improve analytical performance in vicinity of cur rent PQL . MDL from
new method 300.1 is slightly lower than MDL from
300.0. Insufficient data

< current PQL No data < current PQL N o c hange to current PQ L

Glyphosate 0. 06 No N o data < current PQL No data < current PQL No c hange to current PQ L

Hexachlorocyc l openta

diene 0.001 No Data may support lower PQL No data < current PQL; passing rates
variable in vicinity of current PQL R educ tion of current PQL may
be s upported

Lead 0. 005 Y es - not expected to improve analytical performance in vicinity of current
P QL Data indicate no change to

current PQL No data < current PQL No c hange to current PQ L

Mercury 0. 000 5 Yes – may improve analytical performance in vicinity of current PQL. MDL from
new method 245.7 is significantly lower than previous MDLs Data indicate no change to current PQL No data < current PQL No c hange to current PQ L

Methoxychlor 0. 01 No D ata support lower PQL No data < current PQL; passing rates
variable in vicinity of current PQL R educ tion of current PQL may
be s upported

Monochlorobenzene ( C hlorobenzene) 0.005 No No data < current PQL; passing rates high in vicinity of current PQL Data support
l ow er PQL S light reduction of current PQL supportedEPA

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- Year Review EPA 815 -B- 09

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Page 163 Analyte C urrent PQL (mg/L) New or Updated
M ethods? PQL Assessment Results

Current
Ev a luation of

Six

- Year 1
Data Current
Evaluation of

Si x- Year 2 (ERA 1999

- 2004) Data Overall Qualitative
R eco mmendation

Nitrate (as N) 0. 4 Yes - not expected to improve analytical performance in vicinity of current PQL. MDL from
new method 300.1 is higher than that from 300.0. No data < current PQL No data < current PQL No c hange to current PQ L

Nitrite (as N) 0. 4 Yes

- may improve analytical performance in vicinity of current PQL. MDL from
new method 300.1
is lower tha n previous MDLs Data support
low er PQL No data < current PQL; passing rates high in vicinity of current PQL R educ tion of current PQL

s upported

Oxamyl (Vydate) 0. 02 Y es - may improve analytical performance in vicinity of current PQL. MDL from
new method 5 31.2 is lower than previous MDLs Data indicate no change to current PQL No data < current PQL No c hange to current PQ L

Picloram 0. 001 Y es - may improve analytical performance in vicinity of current PQL. New method
515.4 has lower
MDL. No data < current P QL No data < current PQL No c hange to current PQ L

Selenium 0. 01 Y es - not expected to improve analytical performance in vicinity of current PQL Insufficient data

< current PQL No data < current PQL No c hange to current PQ L

Simazine 0. 000 7 No Cannot
det er mine passing rate for
data < current PQL No data < current PQL No c hange to current PQ L

Styrene 0. 005 No N o data < current PQL; passing rates high in vicinity of current PQL Data support
l ow er PQL R eduction of current PQL supported

Toluene 0. 005 No N o da ta < current PQL; passing rates high in vicinity of current PQL Data support
l ow er PQL R eduction of current PQL supportedEPA

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- Year Review EPA 815 -B- 09

- 003
October 2009

Page 164 Analyte C urrent PQL (mg/L) New or Updated
M ethods? PQL Assessment Results

Current
Ev a luation of

Six

- Year 1
Data Current
Evaluation of

Si x- Year 2 (ERA 1999

- 2004) Data Overall Qualitative
R eco mmendation

2,4,5

- TP ( Silvex) 0. 005 Yes

- may improve analytical performance in vicinity of current PQL. New method 515.4 has capability of a lower MDL. Data support
l ow er PQL No data < PQL; passing
rates variable in vicinity of current PQL R educ tion of current PQL may
be s upported

1,2,4

- T richlorobenzene 0. 005 No No data < current PQL; passing rates high in vicinity of current PQL Data support
lo w er PQL R eduction of current PQL supported

1,1,1

- T richloroethane 0. 005 No Data support lower PQL Data support lower PQL R eduction of current PQL supported

Xylenes (total) 0. 005 No N o data < current PQL Data indicate

no c hang e to current PQL 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, nitrit e, oxamyl, pentachlorophenol, picloram and 2,4,5- TP), the MDLs are lo wer (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 qua litatively 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.EPA

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Page 165 

### 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. Fede ral 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 P rimary 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. 1991a. 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 Rul e. 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. An alytical 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

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Page 166 

### 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 Microbiologica l Contaminants; Final Rule. Federal Register . Vol. 67, p. 65888, October 29, 2002.

USEPA. 2003a. EPA Protocol for the Review of Existing N ational Primary Drinking Water Regulations , EPA -815-R-03-002, June 2003.

USEPA. 2003b. National Primary Drinking W ater 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 Regulat ions: 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.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

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Page A-1 

### Appendix A: Listing of New and Updated Analytical Methods

Exhibit A- 1 lists analytical met hods 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, nitrit e, oxamyl, pentachlorophenol, picl oram and 2,4,5- TP), the MDLs are lo wer (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, M DLs are not k nown, and comparison cannot be made. Lastly, in one case (nitrate), new
or revised methods do not indicate a lower MDL.

Exhibit A -1: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR §§141.23, 141.24, and 141.131

Revised/
N ew Method Old Method NPDWR/Contaminant(s) Notes

Source: Guidelines Establishing Test Procedures for the Analysis of Pollutants Under the Clean Water
Ac t ; National Primary Drinking Water Regulations; and National Secondary Drinking Water Regulations;
Meth ods 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 D297 2

- 93C arsenic Methods updates from 1999 Annual Book of ASTM Standards , Vols. 11.01 and 11.02; revisions to 141.23(k)(1) inorganic analysis; per FR notice,
these do not contain substantive changes in procedures or
instrum entation, 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.) D2972

- 97B D 297 2

- 93B

D3645

- 97B D 364 5

- 93B beryllium

D2036

- 98A D 203 6

- 91A cyanide D2036

- 98B D 20 36

- 91B

D4327

- 97 D432 7

- 91 fluoride, nitrate, nitrite

D3559

- 96D D355 9

- 95D lead

D3223

- 97 D322 3

- 91 mercury

D3859

- 98A D 385 9

- 93A seleniumEPA

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Page A-2 

### Exhibit A

- 1: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR § §141.23, 141.24, and 141.131

Revised/
N ew Method Old Method NPDWR/Contaminant(s) Notes

D3859

- 98B D385 9

- 93B with additional tables of method performance data.” No further method

specific explanations were provided.

3120 Bno name/number change arsenic, barium, beryllium, chromium, copper 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 Registe r 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

eq uipment.” Only the 13 methods listed to the left apply to this Second Six

- Year Review of NPDWRs. 4500

- CN - C

cy an ide 4500

- CN - G

4500

- CN - E

4500

- CN - F

4110 B f l uor ide, nitrate, nitrite

4500 -F- B,D

f l uoride 4500 -F- C

4500 -F- E

4500

- NO 3 - F nitrate, nitrite 4500

- NO 3 - E

4500

- NO 3 - D nitrate

4500

- NO 2 - B nitrite

Source: U nr egulated 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.

EPA Method
531.2 none c ar bofuran and oxamyl Available at: http://www.epa.gov/safewater/methods / ; 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.)EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page A-3 

### Exhibit A

- 1: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR § §141.23, 141.24, and 141.131

Revised/
N ew Method Old Method NPDWR/Contaminant(s) Notes

performance tables using data generat ed with more up to date equipment. Accuracy, precision and
d etection limit data generated using this method is superior to that generated with either of the currently approved methods.

Syngenta AG

- 625 none atr a zine “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 01 none

cy an ide ‘‘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 Informa tion Service (NTIS), PB 2001

– 108275, 5285 Port Royal Road, Springfield, VA 22161;
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 i n drinking
water.”

QuikChem
10

– 2 04

– 00

– 1–X none ‘‘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, WI 53218; 414

– 358

– 4200; see §141.23. New method. Validated in both single and multi

laboratory validation studies, QuikChem 10

- 204

- 00 -1- X is “a satisfactory compliance method for total cyanides in drinking water.”EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page A-4 

### Exhibit A

- 1: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR § §141.23, 141.24, and 141.131

Revised/
N ew Method Old Method NPDWR/Contaminant(s) Notes

Source: Nat i onal 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 obtaine d 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 μg/L using this detector versus 5 μg/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 brom at e The advantage of this method is that it is very specific and sensitive to bromate. The single laboratory
d etection l imit presented in the method is 0.3 μg/L.

EPA Method
326.0 brom at e and chlorite Method provides higher quality bromate data than the currently approved EPA Method 300.1 when
bromate concentrations are below 10 μg/ L. EPA anticipates the number of
laborat ories 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 3 2 7.0 off er s advantages over the currently approved methods in that it is not subject to positive interferences from other chlorine (cont.)EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page A-5 

### Exhibit A

- 1: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR § §141.23, 141.24, and 141.131

Revised/
N ew Method Old Method NPDWR/Contaminant(s) Notes

species and it is easier to use. See §
141.131.

SM 4500

- ClO 2 E and
E- 00 chlorite (daily monitoring only) Standard Methods Section 4500

– ClO2 contains the methods for determining
chlorine dioxide residuals and chlorite
and it includes method 4500

– ClO2E.

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.

ASTM D
6581

- 00 br om ate 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: Gui delines 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, 20 03 and Federal Register, Vol.
69 , p. 18166, April 6, 2004

.

OIA

- 1677,
DW none f or 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 technicall y 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, DW only differs from OIA – 1677 in having (a) updated contact information, and (b)
l ess method modification flexibility (references to performance

- based modifications have been removed). Therefore the validation data on OIA

– 1677 is applicable to OIA – 1677, DW. S ee § 141.23.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page A-6 

### Exhibit A

- 1: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR § §141.23, 141.24, and 141.131

Revised/
N ew Method Old Method NPDWR/Contaminant(s) Notes

ASTM
D688 8

- 04 none ASTM Method D6888

– 04 uses a similar technology to Method OIA

– 1677. ASTM D6888

- 03 was proposed with OIA

– 1677, but later refined and proposed as ASTM D6888

- 04 in 70 FR 7909, February 16, 2005. See §
141.23.

D1179

- 99(B) D 117 9

- 93(B) fluoride

ASTM Method updates “incorporate minor technical and/or editorial revisions that improve the methods.” S ee § 141.23. D1688

- 02(A) D 168 8

- 95(A)
copper D1688

- 02(B) D 168 8

- 95(B)

D2972

- 03(B) D 297 2

- 97(B) arsenic D2972

- 03(C) D 297 2

- 97(C)

D3223

- 02 D322 3

- 97 mercury

D3559

- 03(D) D 355 9

- 96(D) lead

D3645

- 03(B) D 364 5

- 97(B) beryllium

D3697

- 02 D369 7

- 92 antimony

D3859

- 03(A) D 385 9

- 98(A) selenium D3859

- 03(B) D 385 9

- 98(B)

D3867

- 99(B) D 386 7

- 90(B) nitrate, nitrite

D4327

- 03 D432 7

- 97 fluoride, nitrate, nitrite

D5317

- 98 (2003) D 531 7

- 93 2,4

- D, 2,4,5

- TP, pentachlo rophenol, picloram ASTM Method updates “incorporate minor technical and/or editorial revisions that improve the methods.” S ee § 141.24.

D6508, Rev.
2 none fl uor ide, nitrate, nitrite A new method that employs capillary
ion el ec trophoresis to determine

co mmon 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 D6508, 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.)EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page A-7 

### Exhibit A

- 1: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR § §141.23, 141.24, and 141.131

Revised/
N ew Method Old Method NPDWR/Contaminant(s) Notes

other approved methods in the working

range.

3111 B

- 99 3111 B [19th] copper

Standard Methods updates include: “...a number [with]... no changes fro m previously approved version, some incorporate minor technical and editorial revisions to improve user

friendliness, update references, and correct errors.” .” S ee § 141.23. 3112 B

- 99 3112 B [19th] mercury

3113 B

- 99 3113 B [19th] an timony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, selenium

3114 B

- 97 3114 B [19th] arsenic, selenium

3120 B

- 99 3120 B [20th] arsenic, barium, beryllium, chromium, copper

4110 B

- 00 4110 B [20th] fluoride, nitrate, nitrite

4500

- C N E

99 4500

- CN E [20th]

cyanide 4500

- C N F 4500

- CN F [20th]

4500

- C N G

99 4500

- CN G [20th]

4500 -F-B- 97 4500

- F- B [20th]

fluoride 4500 -F-C- 97 4500

- F- C [20th]

4500 -F-D- 97 4500

- F- D [20th]

4500

- NO 2 B00 4500

- NO 2 B [20th] nitrite

4500

- NO 3 -E00 450 0- NO 3- E [20th] nitrate, nitrite 4500

- NO 3- F00 4500

- NO 3- F [20th]

EPA Method
245.7 r ev 2.0 245.7 revision 1.0 mercury Reagent and instrumentation changes; MDL is significantly lower than those from other methods.

EPA Method
552. 3 r ev 1.0 New Method dalapon MDL range is lower than MDLs from
most other methods.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page A-8 

### Exhibit A

- 1: New or Revised Analytical Methods since 2000; Review of NPDWRs under
40 CFR § §141.23, 141.24, and 141.131

Revised/
N ew Method Old Method NPDWR/Contaminant(s) Notes

EPA Method
300. 1 none f luoride, nitrate, nitrite 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 provide d in the proposed rule (66 FR 3526).EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B-1 

### 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 facto rs:

**•** 

### Type of detector;

**•** 

### Volume of sample available;

**•** 

### Duration of analysis

T hus, 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-1 summarizes the regulated radionuclides, along with their current PQL, how the PQL was determined, their MCLG, MCL, and the current acc eptance 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 ( **μ** = 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.

E xhibit B-1: U.S. EPA National Primary Drinking Water Standards and Related
Information – Radio nuclides

Analyte Regulatory Detection Limit (pCi/L) 1 PQL (pCi/L) How PQL Determined? MCLG MCL Acceptance Criteria (pCi/L); **μ** =

assigned value 2

Gross Alpha 3 15 PE data Zero 15 pCi/L Average

– 3- 20 pCi/L: **μ** + 8.66; >20

-

< 75 pCi/L: **μ +**  **0.433μ** Range

- 3- 20 pCi/L: 21.8; >20 -< 75 pCi/L:

1.09 **μ**

Radium

- 22 6 1 5 PE data Zero 5 pCi/L (Ra

226 and Ra

228) Average

– 1- 20 pCi/L: **μ** + 0.260 **μ** Range

- 1- 20 pCi/L:

0.654 **μ**

Radium

- 22 8 1 5 PE data Zero 5 pCi/L (Ra

226 and Ra

228) Average

– 1- 20 pCi/L: **μ** + 0.433 **μ** Range

- 1-2 0 pCi/L:

1.09 **μ**

Uranium N/ A 5 PE data Zero 30 ug/L Average

– 2- 35 pCi/L: **μ** + 5.20; >35

-

< 70 pCi/L: **μ +**  **0.173μ** Range

– 2- 35 pCi/L: 13.1; >35 -< 70 pCi/L:

0.436 **μ** Beta particle and photo emitters See individual constituents listed below 4 millirem/ year (total) See belowEPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B-2 Analyte Regulatory
Detection Limit (pCi/L) 1 PQL (pCi/L) How PQL Determined? MCLG MCL Acceptance Criteria (pCi/L); **μ** =

assigned value 2

Gross Beta 4 30 PE data Zero N/A Average

– 4

- 50 pCi/L: **μ** + 8.66; >50

-

< 65 pCi/L: **μ +**  **17.3** Range

- 4- 50 pCi/L: 21.8; >50 -< 65 pCi/L:
43.6

Barium

- 133 N/ A N/A PE data Zero N/A Average

– 9- 50 pCi/L: **μ** + 8.66; >50

-

< 110 pCi/L:

**μ +**  **0.173μ** Range

- 9-5 0 pCi/L:

21.8; >50 -< 110 pCi/L: 0.436 **μ**

Cesium

- 134 10 10 P E data Zero N/A Average

– 10

- 96 pCi/L: **μ** + 8.66; Range

- 10

- 96 pCi/L:
21.8

Cesium

- 137 N/ A 10 PE data Zero N/A Average

– 20

- 100 pCi/L: **μ** + 8.66;
>100 -< 240 pCi/L:

**μ +**  **0.0866μ** Range

- 20

- 100 pCi/L: 21.8; >100

-

< 240 pCi/L: 0.218 **μ**

Cobalt

- 60 N/ A N/A PE data Zero N/A Average

– 10

- 100 pCi/L: **μ** + 8.66;
>100 -< 120 pCi/L:

**μ +**  **0.0866μ** Range

- 10

- 100 pCi/L: 21.8; >100

-

< 120 pCi/L: 0.218 **μ**

Iodine

- 13 1 1 20 PE data Zero N/A Average

– 1- 15 pCi/L: **μ** + 3.46; >15

-

< 30 pCi /L: **μ +**  **5.20μ** Range

- 1- 215 pCi/L: 8.72; >15 -< 30 pCi/L:
13.1

Strontium

- 89 10 5 PE data Zero N/A Average

– 10

- 70 pCi/L: **μ** + 8.66; Range

- 10

- 70 pCi/L:
21.8

Strontium

- 90 2 5 PE data Zero N/A Average

– 2- 45 pCi/L: **μ** + 8.66; Range

– 2- 45 pCi/L:
21.8

Triti um 1, 000 1,200 PE data Zero N/A Average

– 1,000

- 4,000 pCi/L: **μ** + 294 **μ 0.0933**  ; >4,000

-

< 32,000 pCi/L:

**μ +**  **0.173μ** Range

– 1,000

-

4,000 pCi/L:

741 **μ 0.0933**  ; >4,000

-

< 32,000 pCi/L:

0.436 **μ**EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B-3 Analyte Regulatory
Detection Limit (pCi/L) 1 PQL (pCi/L) How PQL Determined? MCLG MCL Acceptance Criteria (pCi/L); **μ** =

assigned value 2

Zinc

- 65 N/ A N/A PE data Zero N/A Average

– 30

- 50 pCi/L: **μ** + 8.66; >50

-

< 360 pC i/L:

**μ +**  **0.173μ** Range

- 30

- 50 pCi/L: 21.8; >50 -< pCi/L: 0.436 **μ**

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 Stro ntium

- 89 from 1991 is less than the regulatory DL from 2000.
2 Acceptance criteria are available at: http://www.nelac

- institute.org and are subject to change over time. 360



### Exhib it B

- 2: Availability of Six- Year 1 PE Data and Six- Year 2 PE/ PT Data for
R adionuclides

Analyte In Six

- Year 1 Data? 1 In Six

- year 2 ERA Data
2002

- 2006?
Gross Alpha N ot available Y es
, some data < PQL

Radium

- 22 6 N ot available Y es
, some data < PQL

Radium

- 228 Not available Y es , some data < PQL

Uranium N ot available Y es
, some data < PQL
Beta particle and photo emitters

Gross Beta Not available Y es
, some data < PQL

Barium

- 133 N ot available Y es ; no PQL

Cesium

- 134 N ot available Y es
, no data < PQL

Cesium

- 137 N ot available Y es
, no data < PQL

Cobalt

- 60 Not available Y es ; no PQL

Iodine

- 13 1 N ot available Y es
, some data < PQL

Strontium

- 89 N ot available Y es
, no data < PQL

Strontium

- 90 N ot available Y es
, no data < PQL

Tritium N ot available Y es
, no data < PQL

Zinc

- 65 Not available Y es ; no P QL

1 Radionuclides were not included in the Six

- Year 1 Review; therefore, no data are available

.EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B-4 

### Exhibit B-3: Evaluation of ERA PT Data – Gross Alpha

0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate Current PQL = 15 pCi/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B-5 

### Exhibit B-4 : Evaluation of ERA PT Data – Radium -226

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate Current PQL = 5 pCi/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B-6 

### Exhibit B-5 : Evaluation of ERA PT Data – Radium -228

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate Current PQL = 5 pCi/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B-7 

### Exhibit B-6 : Evaluation of ERA PT Data – Uranium

0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate Current PQL = 5 pCi/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B-8 

### Exhibit B-7 : Evaluation of ERA PT Data – Gross Beta

0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate Current PQL = 30 pCi/L 75%

### Exhibit B-8 : Evaluation of ERA PT Data – Barium

- 133

0 10 20 30 40 50 60 70 80 90 100

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)% Laboratories Passing

ERA Data 75% Passing Rate 75% EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B-9EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B- 10 

### Exhibit B-9 : Evaluation of ERA PT Data – Cobalt

- 60

0 10 20 30 40 50 60 70 80 90 100

0.0 20.0 40.0 60.0 80.0 100.0 120.0
True Value (pCi/L)% Laboratories Passing

ERA Data 75% Passing Rate 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B- 11 

### Exhibit B-10 : Evaluation of ERA PT Data – Cesium -134

0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60 70 80 90 100
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate PQL Current PQL = 10 pCi/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B- 12 

### Exhibit B-11 : Evaluation of ERA PT Data – Cesium -137

0 10 20 30 40 50 60 70 80 90 100

0 25 50 75 100 125 150 175 200 225 250
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate Current PQL = 10 pCi/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B- 13 

### Exhibit B-12 : Evaluation of ERA PT Data – Iodine -131

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate Current PQL = 20 pCi/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B- 14 

### Exhibit B-13 : Evaluation of ERA PT Data – Strontium -89

0 10 20 30 40 50 60 70 80 90 100

0 10 20 30 40 50 60
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate Current PQL = 5 pCi/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B- 15 

### Exhibit B-14 : Evaluation of ERA PT Data – Strontium -90

0 10 20 30 40 50 60 70 80 90 100

0 5 10 15 20 25 30 35 40
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate Current PQL = 5 pCi/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B- 16 

### Exhibit B-15 : Evaluation of ERA PT Data – Tritium

0 10 20 30 40 50 60 70 80 90 100

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000
True Value (pCi/L)% Laboratories Passing

PQL ERA Data 75% Passing Rate Current PQL = 1,200 pCi/L 75%EPA

– OGWDW Analytical Feasibility Support Document for the Second Six

- Year Review EPA 815 -B- 09

- 003
October 2009

Page B- 17 

### Exhibit B-16 : Evaluation of ERA PT Data – Zinc -65

0 10 20 30 40 50 60 70 80 90 100

0.0 50.0 100.0 150.0 200.0 250.0 300.0
True Value (pCi/L)% Laboratories Passing

ERA Data 75% Passing Rate 75%