Page 1 of 2 Office of Ground Water and Drinking Water

February 29

, 201 6

MEMORANDUM

SUBJECT: Basis for Expedited Approval of Methods from Hach Company

FROM: William Adams, Chemist, and Glynda A. Smith

, Chemist,

OGWDW/ SRMD/TSC

TO: The Record

This memo documents the reviews that were conducted on methods submitted for evaluation through the drinking water Alternate Test Procedure (ATP) program by Hach Company. The memo provides the background information on why EPA is approving these methods through the expedited methods approval process. Each method is discussed individually below in the order in which they appear in the Federal Register notice :

Hach Method 10241: Spectrophotometric Measurement of Free Chlorine in Drinking Water
Hach M ethod 10241 was submitted as an alternate test procedure to Standard Method 4500

- Cl G, which is approved in the drinking water regulations at 40 CFR 141.74(a)(2) and 40 CFR 141.131(c)(1) for the determination of free chlorine in drinking water.

In Hach Method 10241, free chlorine is converted to monochloramine by addition of an ammonia solution to a drinking water sample. In the presence of a cyanoferrate catalyst, mono chloramine reacts with a substituted phenol to form an intermediate monoamine compound. The intermediate monoamine compound couples with excess substituted phenol to form a green indophenol compound which is measured spectrophotometrically at 655 nm. The a pproved Standard Method
4500

- Cl G uses a DPD indicator for spectrophotometric determination of residual free chlorine in drinking water samples. DPD is subject to interferences associated with the presence of manganese, chloramines, and other oxidants. Hac h Method 10241 is not subject to such interferences.

A multi

- laboratory validation study was conducted to compare the performance of Hach Method

10241 with Standard Method 4500

- Cl G

. The data from three laboratories were used in the multi

laboratory valid ation study. An initial demonstration of capability was performed using different drinking water ma tri c es ( e.g. low ionic strength water, “hard” water with 250 mg/L CO 3 , and high TOC water) at free chlorine concentrations ranging from 0. 0 5 to 4.0 mg/L . Precision and recovery data and
detection limits were also determin ed using low and high ionic strength water and tap water sample s drawn from both ground and surface source waters. The complete data summary is provided in the
Hach ATP Validation Report. Briefly, the results are as follows:

 Detection limits determined as MDLs for the three laboratories ranged from 0.02 mg/L to

0.0 9 mg/L for Hach Method 10241 and 0.0 2 mg/L to 0.0 3 mg/L for the reference Standard

M ethod 4500

- Cl G in low ionic strength wat er. MDLs ranged from 0.0 3 mg/L to 0.05 mg/L
for Hach Method 10241 and 0.0 2 mg/L to 0.0 3 mg /L for the reference Standard Method

4500

- Cl G in high ionic strength water. The pooled MDL results for Hach Method 10241Page 2 of 2

were determined to be 0.0 5 mg/L for low ionic strength matrix water and 0.03 mg/L for high ionic strength matrix water. The pooled MDL resu lts for Standard Method 4500

- Cl G
were determined to be 0.0 2 mg/L for low ionic strength matrix water and 0.0 2 mg/L for high ionic strength mat rix water.

 The average recovery for IPR samples in low ionic strength water for the three
laboratories ranged from 9 4 % to 97 % for Hach M ethod 10241 and 9 4 % to 98 % for the
reference Standard Method 4500

- Cl G

. The average recovery for IPR samples in high ionic strength water for the thre e laboratories ranged from 93% to 97 % for Hach M ethod

10241 and 95 % to 99 % for Standard M ethod 4500

- Cl G

. The pooled low ionic stre ngth matrix recovery results ranged from 89.5 % to 1 01 % with a 95% precision of 0.0 2 for Hach

M ethod 10241 and 89.4 % to 1 04 % with a 95% precision of 0.0 2 for Standard Method

4500

- Cl G

. The pooled high ionic stre ngth matrix recovery results ranged from 84.8 % to

1 04 % with a 95% precision of 0.0 2 for Hach M ethod 10241 and 88.3 % to 1 05 % with a 95% pre cision of 0.0 4 for Standard Method 4500

- Cl G

.

 The average matrix spike recovery results for the three laboratories ranged from 96 .3%
to 10 3 % with an RPD range of 0. 5 to 2.0 for Hach Method 10241 and 8 2.5 % to 9 5 % with

an RPD range of 0. 8 to 1. 3 for the reference Standard Method 4500

- Cl G . The pooled matrix recovery results ranged from 89.9% to 110% for Hach Method 10241 and 66.8 % to

11 4 % for Standard Method 4500

- Cl G

.

Based on the results of the validation study, Hach Method 10241 was determine d to be equally as
effective as the reference Standard Method 4500

- Cl G in determining free chlorine in finished drinking

water.

Hach Method 8026: Spectrophotometric Measurement of Copper in Finished Drinking Water
Hach Method 8026 was submitted as an alt ernate test procedure to EPA method 200.7 for determination of copper in drinking water. Method 200.7 is approved in the national primary drinking water regulations at 40 CFR 141.23(k)(1) for the determination of copper by inductively coupled plasma.

Hach Method 8026 measures cuprous copper colorimetrically after complexation with bicinchoninic acid. Measurements are taken using a spectrophotometer set at 560 nm. The intensity of color is directly proportional to the copper concentration. Cupric copper in samples is chemically reduced to cuprous copper prior to complexation. Interferences are mitigated through the use of a chelating agent. This method is performed through the addition of powder pillows containing the required reagents to the drinking water samples. EPA Method 200.7 and other approved methods require expensive atomic spectroscopy

- based instrumentation and skilled analysts. Hach Method 8026 is
based on well

- known complexation principles and uses a less expensive spectrophotometer and pre

packa ged reagents to determine copper concentrations simply and quickly.

A multi

- laboratory validation study was conducted to compare the performance of Hach Method 8026 with the approved EPA Method 200.7. The data from three laboratories were used in the
mult i

- laboratory validation study. An initial demonstration of capability was performed using different matrixes (e.g. low ionic strength water, “hard” water with 250 mg/L CO 3 , and high TOC water) at various copper concentrations. Precision and recovery data a nd detection limits were also determined using low and high ionic strength water and tap water matrixes from both ground andPage 3 of 2

surface source waters. The complete data summary is provided in the Hach ATP Validation Report. Briefly, the results are as follows:

 Detection limits calculated as MDLs for the three laboratories ranged from 0.02 mg/L to 0.07 mg/L for Hach Method 8026 and 0.004 mg/L to 0.01 mg/L for the reference EPA Method 200.7 in low ionic strength water. MDLs were 0.02 mg/L to 0.05 mg/L fo r Hach Method 8026 and 0.006 mg/L to 0.009 mg /L for the reference EPA Method 200.7 in high ionic strength water. The pooled MDL results for the Hach Method 8026 were determined to be 0.03 mg/L for low ionic strength matrix water and 0.03 mg/L for high ioni c strength
matrix water. The pooled MDL resu lts for EPA Method 200.7 were determined to be 0.0 05 mg/L for low ionic strength matrix water and 0.0 06 mg/L for high ionic strength matrix

water.

 The average recovery for IPR samples in low ionic strength water for the three
laboratories was 97.3% to 106% for Hach Method 8026 and 95.0% to 104% for the
reference EPA Method 200.7. The average recovery for IPR samples in high ionic strength
water for t he three laboratories was 93.8% to 105% for Hach Method 8026 and 88.4% to
101% for the reference EPA Method 200.7. The pooled low ionic stre ngth matrix recovery results ranged from 84.9% to 117 % with a 95% precision of 0.0 2 for Hach M ethod 8026
and 82.7% to 118 % with a 95% precision of 0.0 1 for the reference EPA Method 200.7

. The pooled high ionic stre ngth matrix recovery results ranged from 76.4% to 121% with a 95% precision of 0.01 for Hach M ethod 8026 and 71.0% to 113% with a 95% precision of 0.02 for the reference EPA Method 200.7

.

 The average matrix spike recovery results for the three laboratories ranged from 91.3%
to 100% with an RPD of 0.0 to 6.1 for Hach Method 8026 and 88.5% to 99.3% with an
RPD of 0.0 to 1.0 for the reference EPA Meth od 200.7. The pooled matrix recovery results ranged from 79.5 to 110% for Hach Method 8026 and 77.6% to 113% for the reference
EPA Method 200.7.

Based on the results of the validation study, Hach Method 8026 was determined to be equally as
effective as th e reference EPA Method 200.7 for the determination of copper in finished drinking

water.

Hach Method 10261: Total Organic Carbon in Finished Drinking Water by Catalyzed Ozone Hydroxyl Radical Oxidation Infrared Analysis
Hach Method 10261 was submitted as an alternate test procedure to Standard Method (SM) 5310 C for the analysis of total organic carbon (TOC) in drinking water. SM 5310 C is approved in the national primary drinking water regulations at 40 CFR 141.131(d)(3) for the determination of TOC using UV

persulfate oxidation.

Hach Method 10261 determines TOC in drinking water using two reaction mechanisms. Ozone and a base are added to water to produce hydroxyl radicals. The hydroxyl radicals oxidize organic carbon to produce carbon dioxide and sodium oxalate. The sodium oxalate is further oxidized to carbon dioxide via acidification in the presence of a manganese catalyst. The carbon dioxide produced by both oxidation processes is then measured using non

- dispersive infrared spectroscopy. SM 5310 C
inv olves a multi

- step analysis that can be laborious and may not completely oxidize certain organic compounds, leading to low

- biased results. Hach Method 10261 uses an advanced oxidation process to ensure a more complete oxidation.Page 4 of 2

A multi

- laboratory validat ion study was conducted to compare the performance of Hach Method 10261 with the approved SM 5310 C. The data from three laboratories were used in the multi

laboratory validation study. An initial demonstration of capability was performed using different

m atrixes (e.g. low ionic strength water and “hard” water with 250 mg/L CO 3 ) at various TOC concentrations. Precision and recovery data and detection limits were also collected using low and high ionic strength water and tap water matrixes from both ground a nd surface source waters. The complete data summary is provided in the Hach ATP Validation Report. Briefly, the results are as follows:

 Detection limits calculated as MDLs for the three laboratories ranged from 0.04 mg/L to 0.16 mg/L for Hach Method 10261 and 0.004 mg/L to 0.01 mg/L for the reference SM 5310 C in low ionic strength water. MDLs were 0.06 mg/L to 0.14 mg/L for Hach Method 10261 and 0.06 mg/L to 0.17 mg /L for the reference SM 5310 C in high ionic strength water. The pooled MDL re sults for Hach Method 10261 were determined to be 0.02 mg/L for low ionic strength matrix water and 0.0 9 mg/L for high ionic strength matrix water. The pooled MDL
results for SM 5310 C were determined to be 0.10 mg/L for low ionic strength matrix water
and 0.0 9 mg/L for high ionic strength matrix water.

 The average recovery for IPR samples in low ionic strength water for the three
laboratories was from 99.8% to 100% for Hach Method 10261 and 100% to 102% for the
reference SM 5310 C. The average recovery for IPR samples in high ionic strength water
for the three laboratories was 100% for Hach Method 10261 and 100% to 105% for the
reference SM 5310 C

. The pooled low ionic stre ngth matrix recovery results were 100 % with a 95% precision of 0.0 1 for Hach Method 10261 and 101 % with a 95% precision of

0.0 1 for the reference SM 5310 C

. The pooled high ionic stre ngth matrix recovery results

were 100% with a 95% precision of 0.02 for Hach Method 10261 and 102% with a 95% precision of 0.06 for t he reference SM 5310 C

.

 The average matrix spike recovery results for the three laboratories ranged from 101% to
104% with an RPD of 0.1 to 0.8 for Hach Method 10261 and 102% to 110% with an RPD of 0.3 to 9.3 for the reference SM 5310 C. The pooled matrix recovery results were 102% for
Hach Method 10261 and 105% for the reference SM 5310 C.

Based on the results of the validation study, Hach Method 10261 was determined to be equally as
effective as the reference SM 5310 C for the determination of TOC in dr inking water.

Hach Method 10267: Spectrophotometric Measurement of Total Organic Carbon (TOC) in Finished Drinking Water Hach Method 10267 was submitted as an alternate test procedure to Standard Method (SM) 5310 C for the analysis of total organic carbon (TOC) in drinking water. SM 5310 C is approved in the national primary drinking water regulations at 40 CFR 141.131(d)(3) for the determination of TOC using UV

persulfate oxidation.

Hach Method 10267 determines TOC in drinking water by oxidizing samples using acid persulfate digestions to convert TOC into carbon dioxide. The generated carbon dioxide is passed through a

gas

- permeable membrane into an indicator solution that is measured spectrophotometrically at 435 nm. Interfering inorganic carbon is remov ed from the sample prior to digestion by acidification and agitation. Hach Method 10267 uses simple spectrophotometry and pre

- packaged reagents toPage 5 of 2

quickly analyze for TOC concentration.

A multi

- laboratory validation study was conducted to compare the perf ormance of Hach Method
10267 with SM 5310 C. The data from three laboratories were used in the multi

- laboratory validation study. An initial demonstration of capability was performed using different matrixes (e.g. low ionic strength water and “hard” water with 250 mg/L CO 3 ) at various TOC concentrations. Precision and recovery data and detection limits were also collected using low and high ionic strength water and tap water matrixes from both ground and surface source waters. The complete data

summary is provided in the Hach ATP Validation Report. Briefly, the results are as follows:

 Detection limits calculated as MDLs for the three laboratories ranged from 0.11 mg/L to 0.65 mg/L for Hach Method 10267 and 0.04 mg/L to 0.17 mg/L for the reference SM 5310

C in low ionic strength water. MDLs were 0.23 mg/L to 0.39 mg/L for Hach Method 10267 and 0.07 mg/L to 0.24 mg /L for the reference SM 5310 C in high ionic strength water. The pooled MDL results for Hach Method 10267 were determined to be 0.33 mg/L for low i on ic strength matrix water and 0.25 mg/L for high ionic strength matrix water. The pooled MDL
results for SM 5310 C were determined to be 0.09 mg/L for low ion ic strength matrix water
and 0.12 mg/L for high ionic strength matrix water.

 The average recovery for IPR samples in low ionic strength water for the three
laboratories was from 102% to 105% for Hach Method 10267 and 101% to 103% for the
reference SM 5310 C. The average recovery for IPR samples in high ionic strength water
for the three laboratories was 104% to 107% for Hach Method 10267 and 101% to 107%
for the reference SM 5310 C

. The pooled low ionic stre ngth matrix recovery results were
97.5% to 109 % with a 95% precision of 0.0 3 for Hach Method 10267 and 98.3% to 104 %
with a 95% precision of 0.0 1 for the reference SM 5310 C

. The pooled high ionic stre ngth matrix recovery results were 99.4% to 111% with a 95% precision of 0.02 for Hach Method 10267 and 94.1% to 113% with a 95% precision of 0.06 for the reference SM

5310 C

.

 The av erage matrix spike recovery results for the three laboratories ranged from 97.9%
to 101% with an RPD of 0.3 to 3.3 for Hach Method 10267 and 99.4% to 104% with an RPD of 0.0 to 3.8 for the reference SM 5310 C. The pooled matrix recovery results were
94.3% to 105% for Hach Method 10267 and 94.4% to 108% for the reference SM 5310 C.

Based on the results of the validation study, Hach Method 10267 was determined to be equally as effective as the reference SM 5310 C for the determination of TOC in drinking wate r.

Hach Method 10272: Spectrophotometric Measurement of Copper in Finished Drinking Water (Chemkey) Hach Method 10272 was submitted as an alternate test procedure to EPA method 200.7 for determination of copper in drinking water. Method 200.7 is approved in the national primary drinking water regulations at 40 CFR 141.23(k)(1) for the determination of copper by inductively coupled plasma.

Hach Method 10272 measures cuprous copper colorimetrically after complexation with bicinchoninic
acid. Measurements ar e taken using a spectrophotometer set at 560 nm. The intensity of color is directly proportional to the copper concentration. Cupric copper in samples is chemically reduced to cuprous copper prior to complexation. Interferences are mitigated through the us e of a chelatingPage 6 of 2

agent. This method is performed through the use of a copper Chemkey and portable analyzer. Chemkeys are a patented Hach technology in which all reagents needed for analysis are contained within a single package that, when used with the por table analyzer, allows for the detection of target analytes. EPA Method 200.7 and other approved methods require expensive atomic spectroscopy

based instrumentation and skilled analysts. Hach Method 10272 is based on well

- known complexation principles and uses a less expensive spectrophotometer and pre

- packaged reagents to determine copper concentrations simply and quickly. The analyzer used for Hach Method 10272 adds the additional benefit of being a portable analyzer.

A multi

- laboratory validation study was conducted to compare the performance of Hach Method
10272 with EPA Method 200.7. The data from three laboratories were used in the multi

- laboratory validation study. An initial demonstration of capability was performed using different matrixes (e.g.
lo w ionic strength water, “hard” water with 250 mg/L CO 3 , and high TOC water) at various copper concentrations. Precision and recovery data and detection limits were also collected using low and high ionic strength water and tap water matrixes from both grou nd and surface source waters. The complete data summary is provided in the Hach ATP Validation Report. Briefly, the results are as follows:

 Detection limits calculated as MDLs for the three laboratories ranged from 0.01 mg/L to 0.04 mg/L for Hach Method 10272 and 0.004 mg/L to 0.01 mg/L for the reference EPA Method 200.7 in low ionic strength water. MDLs were 0.02 mg/L to 0.03 mg/L for Hach Method 10272 and 0.006 mg/L to 0.009 mg /L for the reference EPA Method 200.7 in high ionic strength water. T he pooled MDL results for the Hach Method 10272 were determined
to be 0.02 mg/L for low ionic strength matrix water and 0.0 2 mg/L for high ionic strength

matrix water. The pooled MDL resu lts for EPA Method 200.7 were determined to be 0.0 05 mg/L for low ion ic strength matrix water and 0.0 06 mg/L for high ionic strength matrix

water.

 The average recovery for IPR samples in low ionic strength water for the three
laboratories was 95.8% to 101% for Hach Method 10272 and 95.0% to 104% for the
reference EPA Method 200.7. The average recovery for IPR samples in high ionic strength
water for the three laboratories was 90.5% to 97.1% for Hach Method 10272 and 88.4%
to 101% for the reference EPA Method 200.7. The pooled low ionic stre ngth matrix recovery results ranged from 88.4% to 110 % with a 95% precision of 0.0 6 for Hach
Method 10272 and 82.7% to 118 % with a 95% precision of 0.0 1 for the reference EPA
Method 200.7

. The pooled high ionic stre ngth matrix recovery results ranged from 81.7% to 107% with a 95% precision of 0.11 for Hach Method 10272 and 71.0% to 1 13% with a 95% precision of 0.02 for the reference EPA Method 200.7

.

 The average matrix spike recovery results for the three laboratories ranged fr om 85.0% to 93.5% with an RPD of 0.0 to 4.5 for Hach Method 10272 and 88.5% to 99.3% with an RPD of 0.0 to 1.0 for the reference EPA Method 200.7. The pooled matrix recovery results ranged from 74.9 to 102% for Hach Method 10272 and 77.6% to 113% for the r eference
EPA Method 200.7.

Based on the results of the validation study, Hach Method 10272 was determined to be equally as effective as the reference EPA Method 200.7 for the determination of copper in finished drinking

water.Page 7 of 2

Hach Method 10258

– Determi nation of Turbidity by 360 o Nephelometry Hach Method 10258 was submitted as an alternate test procedure to Hach FilterTrak Method 10133 which is approved in the drinking water regulations at 40 CFR 141.74(a)(1) for determination of turbidity in drinking wa ter.

In Hach Method 10258, turbidity is determined using a 360 degree nephelometer. A non

- incandescent light source operates at a wavelength of 660 + 30 nm and light scattered by the sample is collected and detected at an angle 90 degrees to the incident light, 360 degrees around the sample vial. This design offers improved sensitivity and resolution relative to the approved method.

A multi

- facility validation study was conducted to compare the performance of Hach Method 10258 with the approved Hach meth od 10133. The study was conducted at seven different drinking water
facilities

- three of them in the European Union (EU) and four in the United States (US). The laboratories
at the US facilities were all certified to analyze compliance drinking water samp les . Of the total seven facilities, three facilities produced treated water from both conventional and membrane filtration water, two facilities produced only conventional filtration treated water, and two facilities produced only membrane filtration treat ed water. The validation included a total of 120 calibration verification
tests with Hach Method 10258 and 40 calibration verification tests with the approved Hach Method

10133 , and 300 matrix spike tests ranging over three different turbidity levels, for each of the two
methods. Because of the large quantity of data evaluated, the following results summarize the key
data:

 The rounded minimum quantitation limit for Hach Method 10258 derived from an earlier p roof
of c oncept s tudy wa s determined to be 0.0005 Nephelometric Turbidity Units ( NTU )

.

 The linear range of the Hach Method 10258 is determined to be 0.0005 NTU to 40 NTU, with a coefficient of variation of 0.99999 (R 2 ). The range in linearity equates to 4 orders of magnitude, 1 order of magnitude greater in range and 40 times greater in upper quantitation than the approved Hach Method 10133

.

 The lowest resolution of the method (lowest level of change in turbidity tha t can be quantified)
is less than 0.0001 NTU. The value has a resolution that is at least three times lower than that attainable with the approved Hach Method 10133

.

 The stability of the Hach Method 10258 360 o i nstrument as evaluat ed by the calibration

v erification results over two months of measurements in 10 different drinking waters, with a calibration verification range of 1 to 20 NTU, has a range of 1.7% to 3.5%. Hach Method 10133 for the same testing period and drinking water but at a single nomina l calibration verification turbidity of 1 NTU (0.800 NTU actual), is 4.4%.

 The combined matrix spike recovery for a filtration treated water and facilities, is 101% of
theoretical with an 8.0% relative standard deviation for Hach Method 10258

. Hach Metho d

10133 has an equ ivalent matrix spike recovery of 101% with a relative standard deviation of
9.2%

.

Based on the results of the validation study, Hach Method 10258 was determined to be equally as effective as the approved Hach FilterTrak Method 10133 for the determination of drinking water turbidity

.