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National Field Manual for the Collection of Water-Quality Data
Comments and Errata

 [image: beaker]

(Revision history for the National Field Manual)

A "Comments and Errata" archive file lists changes incorporated into the National Field Manual from 1999 through July 2005. The home page for each chapter provides links to archived versions or editions.

Note: A zip file containing the National Field Manual chapters, current as of 2/21/2008, is available. Downloading instructions.

To go to a particular chapter, please access the links below.

| Chapter 1 | Chapter 2 | Chapter 3 | Chapter 4 | Chapter 5| Chapter 6 | Chapter 7 | Chapter 8 | Chapter 9 |


Chapter 1. Preparations for Water Sampling

DATE POSTED/
SECTION/PAGE
COMMENTS/ERRATA ACTION
6/2007

A comprehensive chapter is needed on the topics of quality assurance (QA) and quality control (QC).

Revisions to Chapter 1 to address QA/QC are planned for FY 2008
4/2007

Sections of Chapter 1 that relate to surface-water and ground-water sampling preparations should be incorporated into their respective sections in Chapter 4.

Done. See Chapter 4, version 2.0.
7/2006

URL for cited Water Resources Policy Memo No. 99.34 was http://water.usgs.gov/admin/ memo/WRD/wrdpolicy99.34.html.

Updated URL is http://water.usgs.gov/admin/ memo/policy/wrdpolicy99.34.html.
5/2006

Purpose, title, and contents for Chapter 1 are in need of updating.

Work in process for FY 2006-2007 includes change of chapter title to Quality Assurance and Quality Control for Water Sampling. The quality control section that currently resides in NFM 4 will move to Chapter 1, and the information currently in Chapter 1 that is relevant to surface-water and ground-water sample collection is being merged into Chapter 4.
8/2005

For changes incorporated from 1999 thorugh July 2005, go to the archive file.

Currently no changes are noted for version 2.0 dated 1/2005.

Chapter 2. Selection of Equipment for Water Sampling

DATE POSTED/
SECTION/PAGE
COMMENTS/ERRATA ACTION
July 23, 2012
Section 2.2.3, Filtration Systems, and Section 2.2.3.B, Organic Compounds
Add information about use of the Teflon inline filter holder. Add information about use of the syringe filter and sample volume for the DAI-LC/MSMS method for pesticides and some pharmaceuticals. (DAI-LC/MSMS -- direct-aqueous injection liquid chromatrography mass spectrometry). Delete all information about organonitrogen-herbicide filtration and samples, as this is being superseded by the DAI method. Revisions described are being prepared for publication by the end of FY 2012 or early FY 2013.
9/24/2009   The following statement will be added to the pertinent sections of this chapter when the chapter is updated:

The Office of Water Quality advises that preservatives, standards, buffers, and other reagents and substances used in the processes of water-quality field and laboratory activities are not to be used beyond their expiration date, but should be discarded appropriately; i.e., in a manner that conforms with local and federal regulations and that does not impair the quality of a water resource with respect to its purpose or environmental viability.

3/30/2009, section 2.0.3,
p. 19 and Table 2-15
Pages indicate that VPBW or PBW are suitable for collecting blank samples to be analyzed for major ions and trace elements. However, VPBW and PBW are no longer used for inorganics. Only IBW should be used for inorganics.
8/2006 - section 2.4, p. 101Sunscreen and insect repellent are missing from table 2-17. Add to table 2-17:
Sunscreen (wash hands thoroughly after application)
Insect repellent - instead of a DEET-containing repellent, recommend either (a) oil of lemon eucalyptus, or (b) picaridin (a chemical). Reference: http://www.cdc.gov/od/oc/Media/pressrel/r050428.htm
8/2006 section 2.1.1.A, p. 24-30

US DH-2 and US D-96 A-1 samplers are missing and should be added.

Add US DH-2 and US D-96 A-1 samplers to table 2.2; add US DH-2 to fig. 2-1. Incorporate descriptions into text. A commercial version of the DH-2 bag sampler can be found at www.carnettechnology.com as "US DH-2A." The D-96 A-1 is an aluminum version of the US D-96.
6/2006  "Universal" blank water has been discontinued for use as inorganic blank water.
8/2005

For changes incorporated from 1999 through July 2005, go to the archive file.

Currently no changes are noted for version 2.0 dated 3/2003.

Chapter 3. Cleaning of Equipment for Water Sampling

DATE POSTED/
SECTION/PAGE
COMMENTS/ERRATAACTION
March 12, 2012
Sections 3.2 (flowchart), 3.2.1, 3.3.4.A, 3.3.4.C, 3.4
Cleaning procedure for filtration units for inorganic-constituent sampling:
  1. Review the requirements/guidance for precleaning filter units for capsule and disc (AquaPrep-type) filtration units for inorganic-constituent sampling, considering declined/declining analytical levels:
    1. Is it necessary to use blank water or may WSC-produced ASTM Type 1 water be used in the preclean?
    2. Should the procedure be different when the objective is to collect a blank sample?
    3. Determine if the guidance decided on deviates from the rule-of-thumb to collect blanks in the same manner as environmental samples.


  2. Review the requirements/guidance for precleaning filters and filtration apparatus for organic-compound sampling, considering declined/declining analytical levels (answer (a), (b), and (c) above).


  3. Add a section (3.3.4.D?) to provide guidance for the 47-mm Teflon cartridge unit being used for filtering pesticide samples.


  4. Inorganic sampling using capsule/disc filter units :Provide current guidance on whether or not, and under what circumstances, an acid rinse should be added to the procedure.
    1. Verify use only of ultrpure HCl.
    2. Determine if Versapor filter medium can withstand an acid rinse.

In Section 3.2.1, this pertains to any qualifications that should be added with respect to filtration. Check for consistency with Chapter 5, especially Section 5.2.

(Revise the guidance according to answers determined for the issues posed; include footnotes to the various flowcharts, as appropriate)
March 10, 2011
Section 3.3.1, p. 35
Strike the last sentence, first paragraph that says to use acid-rinsed bottles for mercury-analysis samples. The Q29FLD 250 mL bottles no longer are acid rinsed, per NWQL Rapi-Note 09-005. Deleted by strike-through on 2/17/2011: "Glass bottles for samples for mercury analysis also are acid rinsed and should arrive capped."
11/16/2010
Page 64
Inaccurate information is given for the factors to be used when estimating the volume of water storage in sample tubing and needs to be corrected in the text and in footnote 2. The correct conversion is 28.3 L per cubic foot. Footnote 2 uses a single factor (0.1 gal per 10 feet) for the additional rinse requirement. This factor is close to the (incorrect) 0.04 L/ft factor used for 1/2 inch tubing; however, even if the factor were correct it would not apply to 3/8 inch or other diameter tubing. The formula shown also should be revised, as needed. The changes recommended will be made.

9/24/2009   The following statement will be added to the pertinent sections of this chapter when the chapter is updated:

The Office of Water Quality advises that preservatives, standards, buffers, and other reagents and substances used in the processes of water-quality field and laboratory activities are not to be used beyond their expiration date, but should be discarded appropriately; i.e., in a manner that conforms with local and federal regulations and that does not impair the quality of a water resource with respect to its purpose or environmental viability.

8/10/2009   The following guidance given in NFM 2, p. 18, Section 2.0.2, also applies to Chapter 3.

  • Wear powderless nitrile gloves when handling equipment and chemical solutions. Do not allow the water that enters the sample bottle to contact gloved (or bare) hands.
  • After putting the gloves on, rinse them with water while gently rubbing hands together to remove any surface residue before handling sampling equipment.
5/20/2009
p. 42
  • Use 100 mL of IBW...
  • Use 50 mL of IBW...
2/2008
p. 71
Change second dash under the "Field blank" bullet. Rewrite this guidance to reflect current protocol.

"If the same equipment is used at several sites during a single field trip, the equipment must be properly cleaned and stored each time before leaving for the next site. Collect the field blank before collecting the environmental sample. If one field blank will be collected for such a field trip, generally it is collected at the last site unless study needs dictate otherwise."
8/2006
Section 3.3.9
p. 54
Instructions for cleaning the Teflon bag are missing. Instructions are provided courtesy of A. Amsberg and H. Johnson (USGS).

Add to section 3.3.9, at the end of the first paragraph: "The Teflon bag used in bag samplers must be cleaned and field rinsed before use. The special cleaning procedures recommended are described under step 2 on p. 54. The field-rinse procedure is described in NFM 4.1."
Change step 2, p. 54, to read:
Soak components (except for the Teflon bag) in a detergent solution for 30 minutes. Wearing appropriate disposable, powderless gloves, scrub components with a soft brush or sponge and rinse thoroughly (section 3.2.1 or 3.2.2). Change gloves. To clean the Teflon bag:
1. Fill the bottom of the bag with warm 0.1% Liquinox solution (approx. 100-200 mL).
2. Pull the bag (gently) into a tube-like shape; loosely fold the top (opening) over and slosh the solution back and forth from the bottom to the top of the bag.
3. With the bag still pulled into a tube-like shape, hold it horizontally and rotate it around, making sure the Liquinox flows into all of the folds.
4. Rinse with hot tap water, in the same fashion as the soapy rinses; back and forth from top to bottom, then rotating while holding horizontally.
5. Repeat this procedure with 5% HCl.
6. Repeat the rinse technique three times, using fresh DIW.
7. Holding the bag open with one hand, squirt the inside of the bag with methanol (only necessary if samples will be analyzed for organic compounds). Ensure full contact of inside bag surfaces by repeating the sloshing and rolling techniques before decanting waste methanol into approriate containers.
6/2006  "Universal" blank water has been discontinued for use as inorganic blank water.
11/21/2005
Ver. 2.0, 4/2004, pg. 12.
  Add a new first arrow above the existing first arrow, with the following text:
Clean all surfaces (for example, bench and counter tops) on which you will be working. If a disinfectant is used, thoroughly rinse and dry the surface afterwards and be sure to air out the area to remove any fumes from the dininfection agent. Do not expose a sample to the area if fumes remain that could contaminate the sample with an analyte of interest.
11/21/2005
Ver. 2.0, 4/2004, pg. 13.
  Insert after the first sentence or add as a footnote to the first sentence the following:
Refer to NFM 7.1 for sterilization and disinfection requirements when sampling for microbial organisms.
11/21/2005
Ver. 2.0, 4/2004, pg. 14, Table 3-1.

Add a row to the table after the "Detergent" row.

LEFT COLUMN: Disinfectant
RIGHT COLUMN: Hypochlorite wipes (commercially available), dilute bleach solution, or methyl or ethyl alcohol solution.
ADD FOOTNOTE TO TABLE:
Hypochlorite wipes: At 0.525-percent (1:10) dilution, these wipes are more concentrated than that of the bleach solution and could be more corrosive to equipment if not followed by the standard DIW rinse.
11/21/2005
Ver 2.0, 4/2004, pg. 53. #1 under "Disinfecting an electric or steel tape:"
1. Select a disinfectant: either a chlorine bleach solution (described below) or a methyl or ethyl alcohol solution. If using bleach, prepare a dilute 50 mg/L (0.005 percent) solution of common household chlorine bleach (1 mL of bleach to 900 mL water). .... 1. Select a disinfectant: either a chlorine bleach solution (described below), commercially available hypochlorite (disinfectant) wipes, or a methyl or ethyl alcohol solution.
o If using the hypochlorite wipes, be sure to check the expiration date printed on the packet; do not use wipes with expired dates. Note: as these wipes are more concentrated in hypochlorite (0.525 percent) than the bleach solution (0.005 percent), care should be taken to avoid equipment damage.

o To prepare a 0.005-percent (50 mg/L) bleach solution9: (a) Wearing laboratory gloves, add 1 mL of common household chlorine bleach to 900 mL water, then add water to bring it to a volume of 1,000 mL (USEPA, 1982, p. 253, and 1996, p. VIII-41). The bleach solution should be prepared fresh for each day of use (NFM 7.3). (b) Label a polyethylene sample bottle as "Well-Tape Disinfectant" and record the date of preparation, using an indelible marker. (c) Fill the bottle with the dilute disinfectant solution. Cap the bottle tightly, and double-bag it in ziplock plastic bags for transport.
2. At the well site, put on disposable gloves before disinfecting the equipment. Wipe down the section of the tape that was submerged in the well water, using the disinfectant of choice.
o For the bleach or alcohol solution, wet a clean cloth.
o If disinfecting an electric tape, check with the manufacturer before exposing the tape and related equipment to a solvent.
3. Rinse the tape thoroughly with DIW or tap water: prolonged exposure of the tape to chlorine bleach can damage the tape. Take care to keep the tape clean; prevent it from dragging on the ground.

4. Rewind the tape onto the reel and place it into a clean plastic bag for storage and transport.
o Using a clean, dry cloth, dry the steel tape completely before rewinding, to prevent it from rusting.
o Recommendation: If the tape will be stored for a month or more, put a drying agent such as a silica-gel packet into the plastic bag before sealing the bag.
Footnote #9 (see second bullet from no. 1): Prepare a 0.02-percent (200 mg/L) solution if pH is less than 6 or greater than 8.
8/2005

For changes incorporated from 1999 thorugh July 2005, go to the archive file.

Currently no changes are noted for version 2.0 dated 4/2004.

Chapter 4. Collection of Water Samples

=
DATE POSTED/
SECTION/PAGE
COMMENTS/ERRATAACTION
9/11/2013
Section 4.1.3
For the next revision or update to NFM 4, add and expand on the following information provided by Dennis Evans regarding efficiency tests for bag samplers: We will be running an efficiency test for the bag samplers at all sites when using the bag sampler. A rating will be calculated for each sampling. The variability when using a bag sampler in velocities between 1.5 and 2.0 ft/sec will show in that efficiency test. Because sand could be in suspension at a velocity of >1.5 we should try to collect an isokinetic sample each time that criteria is met.  
11/16/2010
Appendix A4-D
Referring to the changes needed on p. 64 of Ch. 3 for estimating the volume of water storage in tubing, the information in this Appendix needs to be reviewed. Any revisions needed will be implemented.
8/10/2009   The following guidance given in NFM 2, p. 18, Section 2.0.2, also applies to Chapter 4.

  • Wear powderless nitrile gloves when handling equipment and chemical solutions. Do not allow the water that enters the sample bottle to contact gloved (or bare) hands.
  • After putting the gloves on, rinse them with water while gently rubbing hands together to remove any surface residue before handling sampling equipment.
2/25/2008
App. A4-C, page APP.C2
(1) Under the "General description" column, first bullet, delete option (a) and reword.
(2) Under the "Purpose" column, delete the second paragraph and replace with wording that reflects the purpose for the field blank.
(Keep the first paragraph.) Second paragraph should read: "Identify contamination of sampling equipment caused by inadequate equipment cleaning, equipment storage during transport from office to field site or between field sites, and ambient conditions at the field site."
1/14/2008
Section 4.3.3
p. 148-149
Change wording on p. 148, 2nd para., and p. 149, Step 1, to remove ambiguity about when samples should be spiked and chilled. p. 148. Add the following sentence: To address bias from degradation, samples should be spiked in the field as soon as possible after collection.

p. 149. The text for Step 1 (before the bulleted list) was replaced with:
Samples should be processed, spiked, and chilled immediately after collection. If spiking is delayed, keep sample chilled until and after it is spiked. Check that the sample bottles are labeled appropriately:
6/1/2007Chapter 4, dated 9/99, needs to be updated. Chapter 4 has been revised and updated extensively. See version 2.0 dated 9/2006.
6/2006  "Universal" blank water has been discontinued for use as inorganic blank water.
5/2006 Surface-water and ground-water sampling protocols need updating. Revisions are being completed in FY 2006 and will be published in FY 2007 or before. Updates include changes to surface-water sampler tables (in the appendix), in addition to other information. Important changes are being made to the ground-water guidance for purging and sampling, including guidance when working at low-yield wells. The quality-control section (NFM 4.3) is being moved from Chap. 4 to Chap. 1.
11/08/04 --
p. CF-5, App. A4-B, and App.A4-C table 1
Update chapter to reflect the closure of the Ocala Water Quality and Research Laboratory Delete reference to the Ocala laboratory. Supplies are available from the USGS "One-Stop Shopping."
5/2/03 -- NFM 4.2.1, Step 3, page 78Additional guidance is needed to properly rinse out the sample line during the purge and before samples are collected. Insert as first sentence for Step 3b: "Discharge initial well water through the waste line that goes to the flowthrough chamber."

Insert as first sentence for Step 3c: "When the water runs clear, switch the flow to the sample line (line that goes to the collection chamber) and allow at least two tubing volumes to pass through so as to rinse and condition the sample line with well water. Then. . . " (continue into next sentence, changing the B in Begin to lower case).
5/2/03 -- NFM 4.2.2, Step 3d, page 86Additional guidance is needed to properly rinse out the sample line during the purge and before samples are collected. Add a fourth bullet: "While purging the first two well volumes, and before starting field measurements, once the well water is running clear, switch the flow from the "waste" line to the sample line, to ensure that the sample line is thoroughly rinsed of methanol and other equipment-cleaning agents."
11/29/02--REF-2 Add reference for Izbicki, John, Christensen, Allen, and Hanson, Randy, 1999, U.S. Geological Survey combined well-bore flow and depth-dependent water sampler, U.S. Geological Survey Fact Sheet 196-99, 2 p., at http://ca.water.usgs.gov/archive/ reports/fs19699.pdf

Add reference for Miller, James, ed., 2002, Ground water atlas of the United States, http://capp.water.usgs.gov/gwa/index.html
4/4/01 -- p. 69 of NFM A4 Third bullet, second to last sentence: "... (2) field measurements must be monitored before collecting samples." "...(2) field-measurement values should be determined before collecting samples, if possible."

Chapter 5. Processing of Water Samples

DATE POSTED/
SECTION/PAGE
COMMENTS/ERRATA ACTION
February 18, 2014
Section 5.4.2
Chemical Treatment
There is a recommendation to incorporate the following protocol into the section on use of chemical preservatives: "Check the expiration date on the preservative ampoule label. Do not use chemical preservatives after the expiration date on the ampoule label." Chapter A5 is in the process of being updated. The recommendation not to use expired chemical preservatives is being incorporated in the draft updated version, which will go through colleague review before publication.
October 4, 2012
Section 5.6.4.A Arsenic Speciation
Due to typographical error, the document refers to the USEPA drinking-water standard for arsenic as 1 ug/L. The correct standard is 10 ug/L. Temporary errata page inserted on October 3, 2012, at front of Section 5.6.4.A version 2.0 dated 8/8/2012, was deleted on October 4, 2012, and the correction was made to Section 5.6.4.A and republished as version 2.1, dated 10/4/2012.
August 8, 2012
Section 5.6.4.A Arsenic Speciation
(A separate section attached under
Ch. A5 on the NFM homepage)
(See the entry dated April 7, 2010.) Section 5.6.4.A has been revised and numbered version 2.0 dated 8/8/2012.
July 23, 2012
Section 5.6.1.F
Revise and update the entire section. The update of this section is underway and publication is expected in early FY 2013.
July 23, 2012
Section 5.6 and 5.6.1, including 5.6.1.B (current priority), 5.6.1.C, 5.6.1.D, 5.6.1.E.
(1) Delete Organonitrogen Herbicides; (2) Revise section to include revised sample container information for the hormone method (Filtered samples LS2434, container HFL; Unfiltered samples LS4434 container type HUN; Samples requiring dechlorination agent, bottle N3600 from One Stop); store frozen if not shipped immediately. (3) Add samples for pharmaceutical analyses by LS 2440 are filtered and collected in 40-mL VOA vials with headspace to allow for expansion (air bubble is not an issue); (4) Make updates to remaining sections of 5.6.1 and incorporate the revised section 5.6.1.F into Chapter 5 when ready. See descriptions enumerated under "Change From." All changes are scheduled to be implemented in FY 2013.
July 23, 2012
Section 5.2.2
(1) Make updates to the intro section to include information on the new hormone, pharmaceutical, and pesticide (DAI) methods; (2) Section 5.2.2.A — add information for the inline filter holder; (3) Section 5.2.2.B — delete organonitrogen method and replace with the syringe-filter (DAI) method; (4) review entirety of organic-compound information in Chapter 5 to ensure consistency with and incorporation of the changes made in the sections cited. See descriptions enumerated under "Change From." All changes are scheduled to be implemented in FY 2013.
April 7, 2010
Section 5.6.4.A
This section of the NFM (filename: 5.6.4.A_v.1.1.pdf) is based on recently discontinued lab schedules for arsenic speciation and needs to be revised. Field extraction is no longer a viable option; the only option for arsenic-speciation analysis is the laboratory extraction method (new lab code 3142). Section 5.6.4.A must be revised (numbering it as version 2.0 and assigning a new date) in accordance with the changes described and provided by NWQL Rapi-Note 10-006, dated 3/19/2010, on the appropriate laboratory code for arsenic species. All references in this section to a field extraction for arsenic speciation should be deleted.
9/24/2009   The following statement will be added to the pertinent sections of this chapter when the chapter is updated:

The Office of Water Quality advises that preservatives, standards, buffers, and other reagents and substances used in the processes of water-quality field and laboratory activities are not to be used beyond their expiration date, but should be discarded appropriately; i.e., in a manner that conforms with local and federal regulations and that does not impair the quality of a water resource with respect to its purpose or environmental viability.

8/10/2009
Section 5.3.2
Solid-Phase Extraction by Carbopak-BT Column This section is replaced with a new section entitled "Instructions for Field Use of Spike Solutions for Organic-Analyte Samples".
8/10/2009   The following guidance given in NFM 2, p. 18, Section 2.0.2, also applies to Chapter 5.

  • Wear powderless nitrile gloves when handling equipment and chemical solutions. Do not allow the water that enters the sample bottle to contact gloved (or bare) hands.
  • After putting the gloves on, rinse them with water while gently rubbing hands together to remove any surface residue before handling sampling equipment.

March 20, 2008
p. 73
  • Pass 100 mL of organic-grade water...
  • Pass 50 mL of organic-grade water...
March 20, 2008
p. 72
See second arrow bullet:
The small-capacity disc filter that is in current use and quality controlled at the NWQL (One Stop item Q460FLD) has a 19.6 cm2 effective filter area and should be rinsed with 100 mL of VPBW
The small-capacity disc filter that is in current use and quality controlled at the NWQL (One Stop item Q460FLD) has a 19.6 cm2 effective filter area and should be rinsed with 50 mL of VPBW
March 2008, NFM 5.0.3/p.20; NFM 5.2.1/p.40,44,46, 50 Sample-collection sequence shown. The order of sample collection for filtered inorganic constituents now shown as: (1) Trace elements and major cations; (2) Separate-treatment constituents (if needed; e.g., mercury); (3) Nutrients; (4) Major anions and alkalinity; (5) Radiochemicals and stable isotopes.

Dissolved organic carbon (DOC) may be collected through a sufficiently rinsed capsule filter after the project-designated filtered inorganic-constituent samples have been collected.
March 2008,
NFM 5.3.2
Delete this section, as the CarboPak-B method no longer is in use by the NWQL. This section, titled "Solid-Phase Extraction by Carbopak-B Column" has been deleted.
March 2008,
NFM 5.6.3.J and NFM 5.6.3.K
Combine these sections into one and replace the guidance with a link to the USGS CFC laboratory. The methods are updated and maintained by the CFC laboratory, which is the source for the field instructions and guidance for analytes used for age-dating, including chlorofluorocarbons, sulfur hexafluoride, dissolved gas, and tritium/helium-3. Therefore, the NFM guidance has been replaced with a link to the CFC laboratory Web pages.
11/25/2008, p. 74b in version 2 of
chap. 5 dated 4/02
Question: Page 74b refers to regulating the DOC filtration pressure to less than 15 psi. A pressure gage is listed as optional in the equipment table. Should a pressure gage be used if employing a peristaltic pump for pressure filtration? Response: In the National Training Center training courses we check the pressure exerted on the filter with a pressure gage; a quick check with a Cole Parmer WU-68612-04 may work (they cost about $12). If a battery-operated pump is being used in the field, make sure the battery has a full charge, as rpm's will degrade as the battery weakens. Check each pump at maximum rpm if you are using a variable speed pump. The peristaltic pumps currently in use for DOC filtration are not strong enough to overpressurize the filter.
10/24/2008, p. 40 in version 2 of chap. 5 dated 4/02 Updates to text are needed to modify capsule-filter procedures and include disc-filter procedures. The heading for 5.2.1.A should read "Capsule-Filter and Disc-Filter Procedures"
Then revise the beginning and ending of the first paragraph to read:
The capsule or disc filter is a disposable, self-contained unit composed of a [delete "pleated"] filter medium encased in a plastic housing.......
The capsule filter, having an effective filtration area of at least 600 cm2, is required when filtering large-volume or sediment-laden samples for trace-element analysis and is recommended when filtering samples for major-ion or other inorganic-constituent (including nutrients and carbon) analyses. The disc filter has an effective filtration of only about 20 cm2 and should be used only when the amount of suspended material in the sample is low (not or barely visible) and for a sample volume of less than 100 mL.

In the second bullet (an arrow), change "Preclean capsule filters..." to "Preclean capsule/disc filters..."
10/24/2008, p. 41 in version 2 of chap. 5 dated 4/02 To prepare the work space, sample bottles, and capsule filter: To prepare the work space, sample bottles, and capsule/disc filter:
10/24/2008, p. 42 in version 2 of chap. 5 dated 4/02 Text is being revised to include disc filters rather than discussing capsule filters exclusively. The following sentence is deleted from the first paragraph:
More rigorous precleaning procedures that include rinsing with trace-metal-grade hydrochloric acid are required for samples containing ppb concentrations of target analytes (table 5-3).
5. Clean the capsule/disc filter. If the filter was precleaned, go to the sections that follow on "To filter a composite sample" or "To filter a pumped sample," as appropriate. The steps below comprise sufficient precleaning of the filter for inorganic analytes at the parts-per-billion (ppb) concentration level. Only CH touches those portions of tubing that will be in direct contact with the DIW or filter.

a. CH: In the processing chamber, remove filter from protective bags.
- Attach pump tubing to inlet connector of filter, keeping tubing as short as possible. Make sure direction of flow through filter matches the direction-of-flow arrow on the side of the capsule, if applicable.
- To help minimize aeration of the sample (usually for ground-water samples), secure a short length of clean fluorocarbon polymer tubing onto filter outlet to extend into the sample bottle so the bottle can be filled from the bottom up.
b. CH/DH: Pump 1 L of DIW through capsule filter or 100 mL through disc filter; discharge waste rinse water through a sink funnel or to a toss bottle.
(Revise the second bullet under b.)
- CH inverts the filter so the arrow on the housing is pointing up to help expel trapped air from the filter during initial filling. Do not allow water to spray onto the chamber walls.
c. Delete "capsule" in the fourth line.
d. Delete "capsule" in the first line.
10/24/2008, p. 43 in version 2 of chap. 5 dated 4/02 Delete text "capsule filter or other" in lines 1 and 2. Lines 1 and 2 read: ...a well using a bailer, consider using a bailer to which the filtration device can be connected....

In #2. on this page, delete every use of the word "capsule."
10/24/2008, p. 44 in version 2 of chap. 5 dated 4/02 Revisions continue. Lines 1 and 2 read: ...DH: Stop the peristaltic pump as soon as the filter is full of sample and air in the filter has been expelled.

1. Collect sample filtrate.
a. CH: Check that there is a tight connectoin between the pump tubing and the filter.
DH: (Keep as is.)
CH: Collect a maximum of 25 mL (capsule filter) or 10 mL (disc filter) of the water to be sampled as it discharges through the filter. Do not exceed the 25 mL or 10 mL requirement.
(The remaining text under "a." remains the same.)
b. DH: Start pump and resume flow from pump to the filter.
CH: Capsule filter--Filter only the next 200 mL of the sample....
Disc filter--filter the next 100 mL of sample; change to a clean disc filter or switch to the capsule filter if a visible amount of suspended material is accumulating on the filter.
(Then continue on to "e.")
e. CH: Field rinse....Use no more than a total of 100 mL of filtrate per capsule filter or 25 mL of filtrate per disc filter to field rinse any remaining bottles for filtered sample.
10/24/2008, p. 45 in version 2 of chap. 5 dated 4/02 "Capsule" is mentioned numerous times. Delete the work "capsule" where used on this page.
10/24/2008, p. 68 in version 2 of chap. 5 dated 4/02Black Box at top of page says "ALERT! Do not field rinse the baked DOC or pesticide bottles." Revise text to read "ALERT! Do not field rinse the baked TOC/DOC or pesticide bottles."

Also, in 3.b. on this page, add the following sentency at the end of 3.b.:
(Replace the air filter at least annually.)
10/24/2008, p. 74a in version 2 of chap. 5 dated 4/02 Addition to text needed. In 2.a. on this page, add the following sentence at the end of 2.a.:
(Replace air filter at least annually.)
8/15/2008
5.2.2.C (p. 61, 72-73); Table 5-6c
(p. 65); 5.6.1.D
(p. 107)
Instructions that permit samples for DOC analysis to be filtered through a high-capacity Whatman capsule filter are to be discontinued immediately and replaced with the option to filter through a Pall Aquaprep disc filter, in accordance with Office of Water Quality Information Note 2008.13, issued 8/6/2008. Use of the Whatman capsule filter, starting with lot number T873, has been discontinued for samples for DOC analysis because of systematic contamination problems. Instructions for use of the capsule filter (One Stop item Q398FLD) for processing the DOC sample have been removed and replaced with the option to use either the NWQL quality-controlled small-capacity disc filter (One Stop item Q460FLD) or the 25-mm glass fiber filter (Q441FLD) with the Teflon DOC-25 filter unit or filter funnel and flask.
6/03/2008
Section 5.6.3.I
QUESTION:
When you collect radon samples, do you use a new needle in the syringe for each sample or can it be reused? The NFM currently advises to field-rinse the syringe with native water at least one time before sampling. Does this suggest that the needle and syringe are reusable? A clarification is needed.
When collecting radon samples, use of disposable needles with disposable syringes is recommended. Use of a glass syringe and reusable, non-boring needle is acceptable, but this equipment must be cleaned appropriately after each use. A field rinse immediately before collecting the sample is required when using either the disposable or the reusable equipment (refer to NFM section 5.6.3.I).
1/16/2008
5.6.1.E
Methylene Blue Active Substances (MBAS) and Oil and Grease
Revise this section with respect to collecting a sample for analysis of oil and grease; add total petroleum hydrocarbons (TPHs). Change section title to: 5.6.1.E. Methylene Blue Active Substances, Oil and Grease, and Total Petroleum Hydrocarbons

EXPLANATION: USGS personnel are advised that analyses for oil and grease and total petroleum hydrocarbons (TPHs) are being contracted to an outside laboratory as of Jan. 15, 2008. This change includes obtaining pre-preserved sample containers from the contract laboratory, and requires that the USGS manager of the DODESP Program be contacted before samples are sent to the contract lab. Do not send these samples to NWQL. For additional information, USGS personnel should access NWQL Rapi-Note 08-001.
9/17/2007
5.6.4.A, Arsenic Speciation
Section author listed as J.R. Garbarino Author list revised to: J.R. Garbarino, M.E. Lewis, and A.J. Bednar
6/28/2007
p. 118, Section 5.6.3.I and
APP-C-3
Change "RUR-SV" to "RURCV" The sample-designation code for Radon-222 has been changed to RURCV.
6/28/2007
p. 116, Section 5.6.3.E
Change "radon" to "radium" The following correction has been made: Label . . . and add the appropriate laboratory code ("LC 794" for radium-226 and "LC 1364" for radium-228).
10/2006  The silver-filter method for processing DOC samples no longer is used by USGS water-quality field personnel. This method will be removed in the forthcoming revision of NFM 5.
6/2006  "Universal" blank water has been discontinued for use as inorganic blank water.
5/16/05 Chapter needs to be updated and compiled to include new sections. Update is in process. Expected completion date of 10/30/05 has been extended into FY 2007.
1/2005 -- 5.6.4.A Update references to McCleskey and others (in press) McCleskey and others was published in Applied Science in 2004.
9/30/04 -- 5.4.2, Chemical Treatment, p. 93, step 5.c. Correct the preservation order and update text to reflect current chemical treatments Correct preservation order and preservatives as follows:
1. Nutrients (4.5 N H2SO4)
2. Organic carbon (4.5 N H2SO4)
3. Trace elements (HNO3)
4. Major ions (HNO3)
5. Mercury (6 N HCL)
6. Others that require acidifying (HCL first)
7. Samples requiring other preservatives (zinc acetate, sodium hydroxide, etc.)
2/23/04 -- 5.2.2, "Filtration"  Starting 2/23/2004, a low-capacity (19.6 cm2) disposable filter-- the "Aquaprep"TM--will be available for USGS use through the One-Stop Shopping program ('Q460FLD--Filter, AquaprepTM, 0.45 micrometer'). This filtration device only is acceptable for filtration of small-volume water samples at sites at which the amount of suspended material is sufficiently low so that the filter will not clog during the sample-filtering process. These special conditions for use must be adhered to strictly. To prepare the 19.6 cm2-AquaprepTM for field use, follow the same procedures as for the 600-cm2 disposable AquaprepTM capsule filter, but use 100 mL (instead of 1,000 mL) of quality-controlled DIW to rinse the interior of the unit.
1/5/04 -- 5.6.1.E, Oil and Grease COMMENT -- The procedure for adding acid to adjust sample pH to 2 or less should provide guidance as to how to determine the volume of acid needed for a given sample. ACTION -- The next version of section 5.6.1.E will be revised by adding the following technical note under Step 3:
TECHNICAL NOTE: To establish the volume of H2SO4 required, collect a separate aliquot of sample and adjust the pH of this aliquot by adding the acid until pH indicator paper verifies that the pH has been lowered to or less than 2. This aliquot is for testing purposes only and is not to be used for oil and grease analysis. Add the volume of acid determined to the sample to be analyzed. Do not dip pH paper, a pH electrode, a stirring rod, or other materials into a sample that will be used for Hexane Extractable Materials or Silica Gel Treated - Hexane Extractable Materials determination.
1/2/04 -- 5.0.1, 5.0.3, 5.6.2 COMMENT: IBW should be used instead of DIW for rinsing bottles used for mercury and other trace-element samples if the DIW is not of known quality and could contaminate the sample. NFM 5.0.1 -- RESPONSE: (page 16, 2nd arrow, 2nd dash), add "inorganic-grade blank water (IBW) or" before the words "deionized water (DIW)" and after "(DIW)" add "of appropriate quality."
Same section, page 18: second dash, add "IBW or" before each occurrence of "DIW."
NFM 5.0.3 -- RESPONSE: (page 21), first sentence, before the word "DIW" add "IBW or"; Table 5-2, add "IBW, inorganic-grade blank water" to headnote. Changes to both bullets -- add "IBW or" before "DIW" in all places and delete footnote 1.
NFM 5.6.2 -- RESPONSE: (page 107), after first sentence add: "Use IBW instead of DIW for the pre-field bottle rinse/fill if the composition of the DIW could contain target analytes at detectable concentrations for the analysis to be performed on the environmental samples. (DIW could have measureable concentrations of trace elements, for example, if the ion-exchange column is nearing its exchange capacity or is defective; DIW should be analyzed periodically to determine that the system is operating as intended). Alternatively, if the pre-field bottle rinse/fill procedure is not being used, the sample bottle should be rinsed in the field twice with IBW, followed by a field rinse with sample (wholewater for wholewater samples, filtrate for filtered samples) before filling the bottle (NFM 5.0.3). The DIW/IBW rinse of bottles for samples being collected for wholewater analysis can be substituted by field rinsing with sample a minimum of three times before filling the bottle."
5/21/03 -- 5.6.3.K, Chlorofluorocarbons, p. 122-125. A new method for collecting CFC age dating samples has been developed that eliminates the need for flame sealing of the samples for most sampling applications. Add the description of the new method to all appropriate references in Chapter 5, including section 5.6.3.K. (Chapter 5 is in the process of being revised and new instructions will be incorporated.) A new method for collecting CFC age dating samples has been developed that eliminates the need for flame sealing of the samples for most sampling applications. The new method is similar to the method for collecting dissolved gas samples. Bottles with special caps are filled and capped under water. Check for information at the webpage water.usgs.gov/lab/cfc/ under "New Sampling Method for CFCs." The new method simplifies sample collection greatly. If long-term archival of samples is desired, the original flame sealing technique can still be applied.
11/29/02 -- REF-1  Add reference to Izbicki, John, Christensen, Allen, and Hanson, Randy, 1999, U.S. Geological Survey combined well-bore flow and depth-dependent water sampler, U.S. Geological Survey Fact Sheet 196-99, 2 p., at ca.water.usgs.gov/archive/reports/fs19699.pdf
3/17/01 -- CFC sampling, p. 123-128 of NFM A5COMMENT: CFC sampling -- SF6 sampling methods and information can be found at http://water.usgs.gov/lab/ cfc/sampling/sf6.html. This information should be used in conjunction with the instructions for CFC sampling on p. 123-128 of NFM A5, for samples to be analyzed by the USGS CFC Laboratory.Section is being updated.
3/17/01 -- Dissolved gases sampling (in ground water).Comment: Sampling procedures for collection of methane and other dissolved gases in ground water can be found at http://water.usgs.gov/lab/dissolved-gas/ and in "Baedecker, M.J., and Cozzarelli, I.M., 1992, The determination and fate of unstable constituents of contaminated groundwater, in Lesage, Suzanne, and Jackson, R.E., eds., 1992, Groundwater contamination and analysis at hazardous waste sites: New York, Marcel Dekkar, Inc., p. 425-461." The method to be selected depends on study objectives, site conditions, and the analyzing laboratory.
Suggestion: Collection and processing methods for commonly sampled gases should be added to NFM Chapter A5
11/8/00 -- Appendix A5-A, p. APP-A-2, column 1, Append to table a listing for "Ultraviolet-absorbing substances"

Comment: An entry for ultraviolet absorbing substances should be added to the table in the future.

In progress. Bottle type and other instructions are in development. Contact Ron Brenton/NWQL (rbrenton@usgs.gov, 303-236-3210) for update.
10/27/00 -- 5.3 Solid-Phase Extraction by C-18 Column - pages 77-82 A COMMENT has been made to update the C-18 SPE method, method 2011, and change the reference to Sandstrom and others (2000). Add to Fig. 5-2 a line for "Extraction Date". Add a line to Fig. 5-3 about the addition of NaCl to the sample in the sample field form for 2051. NO CHANGE AT THIS TIME.
ANALYSIS: Users are alerted to this information and that these changes will be made in a future version but, at this time, have been assigned a noncritical status.
10/19/00 -- Appendix A5-A, page APP-A-1 In fourth row, last column, change "Filtered sample (0.7-um GF/F), untreated. Chill/maintain at 4 degrees C." Replace with "Raw, untreated sample. Chill/maintain at 4 degrees C."

Chapter 6. Field Measurements

DATE POSTED/
SECTION/PAGE
COMMENTS/ERRATAACTION
September 10, 2013
Section 6.2, Dissolved Oxygen
Version 3.0 has been released. Section 6.2 has been updated and published as Version 3.0.
June 10, 2013
Section 6.2, Dissolved Oxygen
Version 3.0, the update to version 2 that currently is being prepared for publication, includes an unresolved question regarding use of the air-calibration chamber in water method for calibration of optical DO equipment. The following comment arose after report approval and could not be addressed in version 3.0 of section 6.2:

The chamber in water method is in use at some Water Science Centers for calibration of optical sensors. This method may be the only option to satisfy the requirements of step 3 below and technical note-6 (see below) on very hot days when the water to be measured is quite cold. Would laboratory calibrations be less accurate when measured waters are colder than about 15 °C or warmer than about 35 °C?

        Step 3. To the degree possible, the temperature in the chamber should approximate the temperature of the water body in which DO will be determined within about 10 °C.

        Technical Note-6: Most instrument manufacturers recommend calibrating at temperatures that are at least within 10 °C of the ambient water temperature. The most accurate calibration will be achieved if the temperature difference between the environmental water and the calibration chamber is minimized as much as possible.
The suggestion is made that the air-calibration chamber in water method is applicable to optical (luminescence) equipment as well as to amperometric equipment and should be added as a valid calibration option for optical sensors.

Response from NFM managing editor: In previous versions of this DO-sensor calibration guidance, and in accordance with DO-instrument manufacturers, use of that method for optical-sensor calibration was ruled out. Any change to that guidance needs to be explained, peer reviewed within the USGS and by manufacturers, verified, and the results documented. At this writing, the change suggested should be incorporated in future updates only upon verification that the method (described in version 3.0 as Procedure 4 (air-calibration chamber in water)) can be applied reliably in the given environment with the given equipment. Quality-control and quality-assurance testing also should be documented, as should the caveats for when the method is not applicable or advisable.

Responses from three manufacturers of DO equipment used most commonly by USGS projects:
  1. YSI—The method is certainly valid when done properly, however I do feel that this method has the highest risk of water droplets not being detected on the thermistor or membrane which could cause a larger measurement error. We could also recommend that a user test their particular equipment in a lab setting to see what the accuracy is when calibrating at room temperature and measuring in colder or warmer field conditions. If this accuracy is within their field QA/QC requirements then the field calibration step could be eliminated saving time. If you have site knowledge you can also calibrate in a saturated water environment that is within 10 degrees of the expected in situ environment.
  2. In-Situ—From our experience, we have not seen any variation in performance from any of the methods if done accurately. Procedures 1-3 are more stable and easy to use whereas I also have some concerns on Procedure 4 [the air-calibration chamber in water method]. With Procedure 4, you are up against pressure differentials and vapor properties of water at various temperatures. If done correctly, it should produce accurate results, but there is more room to introduce error. I am not opposed to leaving it in the method for optical sensors, but there needs to be some notes and/or warnings on where the errors could occur. I like [YSI’s] idea … on recommending a user test the equipment prior to use. This is good practice in general.
  3. Hach—... when it comes to a DO percentage saturation calibration, the goal is always the same. A 100% saturated environment needs to be created and the oxygen sensor, the sensors for the dependency parameters (temperature and conductivity/salinity, if available) and the electronics should be in this environment – all at the same temperature ideally. Complications arise when considering manufacturer-to-manufacturer sensor design differences that can legitimately make one method “better” for one instrument or sensor type than another. This is why heavy weight should go to the recommendations of the manufacturer. The calibration instructions included with Hydrolab sondes take all this into consideration, as is most likely the case with other instrument and sensor manufacturers. Because we let the sonde do the adjustments for temperature and salinity based on accepted compensation methods, we recommend avoiding the complications and risks that come with calibrating near the temperature expected in the measurement environment, whether in the field or a contrived laboratory environment. From my perspective, best practices of calibration always start with process consistency and minimization of risk.
June 10, 2013
Section 6.2, Dissolved Oxygen
The following review comment arose after report approval and could not be addressed in version 3.0 of section 6.2:
     A better way to approach [how the calibration sections of version 3.0 are organized] would be to characterize the methods as air-saturated water and water-saturated air (includes towel and chamber methods). There is no difference between a chamber in air or in water provided the temperature is stable and sensors are vented to the atmosphere.
This suggestion was responded to by the In-Situ technical support team as follows: ... in favor of ... [the] suggestion and modifying the section to Air-Saturated-Water and Water-Saturated-Air. Your Air-saturated-water method is the bucket method with a bubbler whereas there are three options for Water-Saturated-Air – the 100% saturated air chamber at ambient temperature, the wet towel method at field temperature, and the 100% saturated air chamber at expected sample temperature.

From F. Wilde: The suggested reorganization is documented here for consideration for the next update of Section 6.2.

May 16, 2013
Section 6.2, Dissolved Oxygen
Current version of NFM 6.2 is being updated and parts rewritten. Incorporate changes to computation of DO solubility in text and tables. NFM 6.2, version 3.0, constitutes a full revision of the previous version. It has been approved and is being prepared for publication.
May 16, 2013
Section 6.7, Turbidity Home Page
  1. The turbidity parameter and methods codes (May 2012) spreadsheet that currently is linked to the html homepage for NFM 6.7 near the bottom of the page under "For more information" needs to be updated.
  2. Move the link on the homepage up as the last entry under Contents.
  1. The spreadsheet has been updated and linked to the homepage.
  2. The link has been moved and a notice of the update and new link location added to the homepage section titled "USGS Internal Notices."
May 16, 2013
Section 6.3, Specific Electrical Conductance
This section needs to be updated. First draft of an update and rewrite has been received. Anticipated time of republication is in FY2014 - 2015.
September 10, 2012
Section 6.6
Update Section 6.6, version 3 and replace it with the new version. The new version replaces the "simple speciation method" for calculating carbonate species with the "advanced speciation method." Section 6.6, version 3, has been replaced with Section 6.6, version 4.0. Version 4.0 provides guidelines and establishes policy for USGS projects, implementing use of the "advanced speciation method" as the standard method for calculation of carbonate and bicarbonate species. The simple speciation method has been discontinued. Explanation of this method and policy change is given in Technical Memorandum qw12.05 (see http://water.usgs.gov/admin/memo/QW/).
March 8, 2012
Section 6.8
Provisional updates to:
p. 16, 18, and 19.
The requirements for calibration checks of digital thermistors in NFM 6.8 that reference or repeat protocols cited in NFM 6.1 are out of date in some respects, which especially is a concern with regard to groundwater applications. Until the updates and revisions needed can be studied and completed, make the following provisional changes to the pages listed: Provisional strike-outs and edits added in red to these pages that pertain calibration of sensors, in particular, temperature sensors. Changes made directly on the pdf pages and were dated, as follows: "Note 3/8/2012: Calibration requirements ... are under review." DONE 3/8/2012
March 8, 2012
Section 6.8.3B, p. 36
Second paragraph
If the purpose of sampling is to obtain field measurements only, these data can be obtained in situ by deploying the multiparameter sensor or sonde downhole, followed by a submersible pump to draw water upward. If water-quality samples will be collected, pumping the water from the well to and through a flowthrough cell that contains the sonde or sensors is a preferable and efficient method for collecting field-measurement data without having to remove and redeploy sampling equipment." If the purpose of sampling is to obtain field measurements only, these data can be obtained in situ by deploying the sensor or multiparameter sonde downhole, followed by a submersible pump to draw water upward. If water-quality samples will be collected, pumping the water from the well to and through a flowthrough cell that contains the sonde or sensors is another efficient method for collecting field-measurement data without having to remove and redeploy sampling instruments." DONE -- 3/8/2012
August 15, 2011
Section 6.2
Update of NFM 6.2
Global changes to text, tables, and appendices with respect to change in methods for computing DO solubility Conform entire section to the change in computation of DO solubility as described in Water Quality Technical Memorandum 2011.03.
March 10, 2011
Section 6.0, p. 5
Tables 6.0-1
Under column "Stabilization criteria," add criteria needed for continuous water-quality monitor use per Wagner and others (2006). pH — second sentence now reads: "Allow +/- 0.3 pH units if drifting persists, if measurement is in low-conductivity (~75 µs/cm) water, or for continuous monitor".
DO — added: (+/- 0.3 mg/L for continuous monitor).
March 10, 2011
Section 6.2, p. 4 and p. 7
Tables 6.2-1
Added note to bottom of page 4 "This section addresses DO measurement using single or dual (DO and temperature) instruments. Guidelines, in particular stabilization criteria, are provided in Section 6.8 for use of multiparameter instruments and in Wagner and others (2006) for use of continuous water-quality monitors." On table 6.2-1, p. 7, under "DO," add the criterion for continuous monitor use. Note has been added to p. 4. On p. 7, the following has been added to the DO section, last line: "(+/- 0.3 mg/L when deploying a water-quality continuous monitor; see Section 6.8 and Wagner and others, 2006)."
March 10, 2011
Section 6.8, p. 34
Table 6.8-5
Added the DO and pH criteria when using continuous water-quality monitors. The stabilization-criteria column for pH and DO now read —
  • pH: +/- 0.1 to 0.2 pH unit; if drifting persists or if measuring low-conductivity waters (</ = 75 µs/cm), allow +/- 0.3 pH units)
  • DO: +/- 0.2 mg/L to +/- 0.3 mg/L
  • Turbidity: a semicolon was added after "turbidity 100 FNU"
October 26, 2010
Section 6.2,
Tables 6.2-6 and 6.2-7
  The equations used to calculate DO solubility are under review and revisions to Tables 6.2-6 and 6.2-7 are expected as a result of this review.
January 28, 2010
Section 6.3, Page 4
  Add the following guidance: A good rule of thumb is to record on the standard the date that it is opened. This is especially applicable for values less than 100 µs/cm and greater than about 30,000 µs/cm. Low conductivity standards tend to concentrate with head space in the container and high conductivity standard values tend to diminish if not shaken to redissolve precipitates. Also, bringing additional bottles of standard with different conductivity may help troubleshoot a problematic lot of standard."
January 28, 2010
Section 6.3, Page 4
Change the sentence "Prepare standards outside this range or order them from suppliers of chemical reagents." The sentence should read "Order standards outside this range from suppliers of chemical reagents."
January 28, 2010
Section 6.3, Page 9
Last bullet under Step 14 says: Switching instrument calibration scales could require recalibration. Remove the last bullet under Step 14, as it reflects information that is applicable only to older analog meters.
January 28, 2010
Section 6.3, Page 11
The equation in NFM 6.3, p. 11 contains a rounded constant (0.02) in the equation and should be changed to the value in Standard Methods (0.0191).
August 5, 2009
Section 6.2.1
Luminescent-sensor method The term "luminescent-sensor method" should be more correctly worded "luminescence-sensor method" throughout 6.2.1.
July 14, 2009
Section 6.3
QUESTION: When taking field parameters, for example for conductivity, what does (+/-3% of SC> 100 uS/cm) mean?

I have gotten several opinions on how to interpret this and cannot find anything in the NFM or elsewhere that states it obviously.

Example of 5 minute measurement values:

   1010
   1020
   1025
   1022
   1041

Here are some opinions I have received:

  1. 3% of 1010 (minimum value) = 30.30, all values ARE NOT within


  2. 3% of 1041(maximum value) = 31.23, all values ARE within


  3. 3% on either side (+/-) of the median, all values ARE within


  4. 3% on either side (+/-) of the mean, all values ARE within


  5. 1.5% on either side (+/-) [3% total] of the median, all values ARE NOT within


  6. 1.5% on either side (+/-) [3% total] of the mean, all values ARE NOT within

What is the +/- compared to?

RESPONSE: The NFM is somewhat vague here, but the +/-3% is typically applied to the maximum, as you described in opinion #2.

You may see less variation in your measurements if:

  1. The well is sufficiently developed and properly purged (typically monitor wells are not well developed and may require larger purge volumes than supply wells).


  2. The pump rate is about 500 mls/ minute (this is usually a lower rate than used to purge and reduces the potential for drawing water from different parts of the aquifer).


  3. Water levels show little variation while purging and sampling (variations may indicate withdrawal from different parts of the aquifer).

June 5, 2009
Section 6.6.1 (p. 5)
Section 6.6.1.A (p. 8)
Section 6.6.4.A (p. 19)
Add guidance to the alkalinity/ANC section on how and when to check and correct calibration for the digital titrator. Page 5, second arrow bullet:
–delete "is not as accurate as a buret, but"

Page 8: Add the following sentence to the end of the first paragraph: "Follow manufacturer's instructions and the guidance below for maintenance of the digital titrator."

Page 8: Add the following information to the bottom of page 8:
"Digital titrator: Perform a calibration check on the accuracy and precision of the digital titrator annually (or more if routine quality-control checks indicate a possible problem) by using either reference samples or by comparing the results of an alkalinity or ANC measurement with those determined by performing a buret titration on the same sample. If results show an equipment calibration problem, contact the manufacturer for repair or replacement."

Page 19: At the end of the first arrow bullet, top of page, last sentence: replace the final period with a comma and add: "and whenever the accuracy or precision of the digital titrator is in question. See the guidance in section 6.6.1.A on maintenance of the digital titrator."
May 18, 2009
Section 6.2
The section of the National Field Manual on dissolved oxygen needs to be updated to provide better guidance on the use of optical dissolved-oxygen (DO) sensors. Currently, optical DO is mentioned only in passing although this technology now is in use at most WSCs. Inconsistencies between the optical and amperometric sensor guidance needs to be addressed, especially in stating for optical sensors the lower bounds of accuracy below which data is to be reported as "less than." The technology has matured sufficiently and proven its usefulness such that it warrants a more complete discussion in the NFM. This request has been placed in the queue for revisions to section 6.2 of the National Field Manual. However, because of the publication of Section 6.8 that addresses use of the optical DO sensor with multiparameter instruments, the revision of NFM 6.2 is not listed as having high priority.

With respect to the bounds of accuracy, this depends on the technology used by the manufacturer and the concentration of dissolved oxygen in the water being measured. For example,

  • In-Situ RDO sensor and Hach LDO sensor list the following specification for measurement accuracy: +/- 0.1 mg/L from 0 to 8 mg/L, and +/-0.2 mg/L from 8 to 20 mg/L of DO in water.
  • YSI ROX sensor: +/- 0.1 mg/L from 0 to 20 mg/L or 1 percent of the reading, whichever is greater; and for waters with 20 to 50 mg/L, apply +/- 15 percent of the reading.
  • Eureka Luminescence DO sensor: +/- 0.1 mg/L in water with less than 8 mg/L DO; +/-0.2 mg/L in water from 8 to 25 mg/L DO.

Therefore, DO measurements using optical sensors should be reported as "less than" (<) when the value measured is below 0.2 mg/L; at DO values of 0.2 mg/L and above the measurement should be reported to the nearest 0.1 mg/L; and should be recorded as "greater than" (>) 20 mg/L for measurements that exceed 20 mg/L of DO.

May 11, 2009
Section 6.0
Section 6.0, "General information and guidelines" by F.D. Wilde and D.B. Radtke, dated 8/2005. Section 6.0 has been revised to version 2.0, "Guidelines for field-measured water-quality properties" by Franceska D. Wilde, dated 10/2008.
Aug. 5, 2008
Section 6.2
Comment received: The NFM recommends use of spectrophotometric methods for accurate measurement of dissolved oxygen (DO) below 2.0 mg/L. However, there are no reporting guidelines for low DO values measured using amperometric or luminescent methods. It has been recommended that such values be reported as estimated. Consistency in guidance for both measurement and reporting is needed. (Response in preparation.)
July 9, 2008
Section 6.8
p. 28, 29, 33
StableCal is listed as a registered product. More commonly, Hach "StablCal" is the product name used. References to "StableCal" have been changed to "StablCal."
Feb. 15, 2008
Section 6.8
p. 7 and p. 8
In the headnote for Table 6.8-2 (p. 7) and in the Description column for "Turbidity standard"
(p. 8) the "greater than or equal to" symbol is used.
Change the symbol to a "less than or equal to" symbol.

The version number for this section changes from version 1.0 to version 1.1.
Dec. 20, 2007
Section 6.6.4
p. 13 and p. 26
  Notes have been added to the pages that the inflection-point titration (IPT) method also is known as the "incremental titration method."
Dec. 10, 2007
Section 6.1
p. 7 and p. 21
Change "Wagner and others (in press)" Wagner and others (2006)
Dec. 6, 2007
Section 6.6.7, p. 48
If calculating ANC, alkalinity, bicarbonate, or carbonate in milligram units, then report:
- Less than (<) 1,000 mg/L and greater than (>) 10 mg/L to whole numbers.
- 1,000 mg/L and above, up to three significant figures.
Change made to online report on Dec. 6, 2007:
For measurements made using section 6.6.4 procedures, when calculating ANC, alkalinity, bicarbonate, or carbonate in milligram units, report:
- Less than (<) 1,000 mg/L and equal to (=) or greater than (>) 100 mg/L to whole numbers; however, to the tenths place if less than 100 mg/L.
- 1,000 mg/L and above to three significant figures.
Nov. 16, 2007
Section 6.6.5.A, p. 44
1.0.1 Change made to online report on Dec. 3, 2007:
At the bottom of page 44, change "1.0.1" to "1.01"
Nov. 16, 2007
Section 6.6.7
The rounding of values between 10 and 100 mg/L do not coincide with the default codes in NWIS for rounding. This issue is being examined. A notice of how this will be resolved will be announced here and the National Field Manual will be updated appropriately. (SEE UPDATE ABOVE FOR DEC 3, 2007)
July 20, 2007 -- Section 6.0,
Table 6.0-1
Change the text and the value in the row for dissolved oxygen. Under "Dissolved oxygen:" change "Amperometric method" to "Amperometric/luminescent method". Either the amperometric method or the luminescent-sensor method can be used.

In the second column for dissolved oxygen, change +/- 0.3 mg/L to +/- 0.2 mg/L
June 2007 A new section is needed that provides guidelines when using multiparameter instruments. A new section 6.8 on multiparameter instruments is being prepared. The target date for release is Sept. 2007.
April 23, 2007 -- Section 6.6, Alkalinity and Acid Neutralizing Capacity There is an apparent contradiction or mismatch of information between the National Field Manual and NWIS for reporting of carbonate data as parameter code 63788. The National Field Manual infers that carbonate values can be reported down to 0.1 mg/L. The Parameter Code rounding array for the carbonate parameter 63788 infers that the carbonate value should be reported as a whole number, or down to 1 mg/L. The discrepancy will be corrected with the release of NWIS 4.7, scheduled for September 2007.
March 28, 2007 -- Section 6.5, Reduction-Oxidation Potential (Electrode Method), p. 22 A citation is incorrect in the References: Sato, Michiaki, 1960, Dissolved oxygen in aqueous systems: Economic Geology, v. 55, p. 928-949. The correct citation is: Sato, Motoaki, 1960, Oxidation of sulfide ore bodies, 1. Geochemical environments in terms of Eh and pH: Economic Geology, v. 55, p. 928-961.
August 22, 2006 -- Section 6.6, Alkalinity and Acid Neutralizing Capacity 2nd Edition, 9/2001 Version 3.0, 7/2006, contains minor updates. The term "edition" was changed to "version" to be consist with the tracking convention for other sections.
August 14, 2006 -- NFM 6.5.1.B, page 6
and NFM 6.5.2, page 8
Add information about disposal of ZoBell's solution. Page 6, add new paragraph after step 3: To dispose of ZoBell's solution after use:

o Do not dispose of through the sewer system. Use a qualified hazardous waste hauler and Treatment, Storage, or Disposal Facility (TSDF) (see http://www.epa.gov/radiation/mixed-waste/mw_pg11a.htm)
o Note that the cyanide compounds in this waste stream are at a concentration of one percent and can be classified as a RCRA D003 (reactive) or non-hazardous waste stream. It is up to the generator of the waste to make this determination.
o Whether you dispose of this as RCRA haz or non haz, the U.S. Department of Transportation (DOT) shipping name is cyanide solutions, n.o.s. 6.1 (Toxics).

Also on p. 6, change the Black Box to:
"CAUTION -- ZoBell's solution is toxic - handle with care and dispose of ZoBell's-solution waste according to governmental regulations."

Page 8, third arrow, add a third dash:
"- ZoBell's is considered a hazardous waste; after use, contain the waste properly for subsequent appropriate and legal disposal. If in doubt, consult your safety officer."
June 20, 2006 -- NFM 6.5, Section 6.5.5 Report the calculated Eh in mV to two significant figures. Potentials are reported to the nearest 10 mV, along with the temperature at which the measurement was made, the electrode system employed, and the pH at the time of measurement. Report Eh in millivolts (mV), calculated relative to the standard hydrogen electrode. Do not report raw data. Replicate measurements should stabilize within plus or minus 10 mV. Report the median of at least three replicate measurements to the nearest mV. If continual drifting without stabilization occurs after extending the measurement period, record this difficulty on the field form along with the length of time during which Eh values were monitored.
June 16, 2006 -- Section 6.2 Update description of the equipment for the spectrophotometric method. Version 2.1, 6/2006; table 6.2-4. the VacuVial catalog number was changed to K-7553 and information was added about the photometer.
June 7, 2006 -- Section 6.2 Version 2.0, May 2006 Version 2.1, June 2006. Updates were made to the example information listed for CHEMetrics, Inc.
June 6, 2006 -- Section 6.0, p. 27 In the footnote for fig. 6.0-3, the URL was http://water.usgs.gov/owq/turbidity/ turbidity.pcodes_mcodes.update.xls The updated URL is:
http://water.usgs.gov/owq/turbidity_codes.xls
May 23, 2006
Section 6.2, Dissolved Oxygen
The original version, dated April 1998, is due for an update to reflect new technology and method changes. Version 2.0, 5/2006: A new method has been added for DO measurement by luminescent sensor technology.

Updates have been made for the amperometric and spectrophotometric methods. At DO concentrations of less that 2 mg/L (instead of 1 mg/L), the spectrophotometric method is recommended. The iodometric (Winkler) method has been moved to the main body of the report.
May 23, 2006 A section on the use of multiparameter instruments is needed. A new section is being prepared on the use of multiparameter instruments to collect field measurements. Publication is scheduled for FY 2007.
May 3, 2006 -- Reference update for Chapter 6 In "Selected References" for NFM 6 sections, the following reference is being replaced: Wagner, R.J., Mattraw, H.C., Ritz, G.F., and Smith, B.A., 2000, Guidelines and standard procedures for continuous water-quality monitors--Site selection, field operation, calibration, record computation, and reporting: U.S. Geological Survey Water-Resources Investigations Report 00-4252, 53 p. The updated report is: Wagner, R.J., Boulger, R.W., Jr., Oblinger, C.J., and Smith, B.A., 2006, Guidelines and standard procedures for continuous water-quality monitors--Station operation, record computation, and data reporting: U.S. Geological Survey Techniques and Methods 1-D3, 51 p. + 8 attachments, online only at http://pubs.water.usgs.gov/tm1d3
April 5, 2006 -- 6.1, Temperature Version 1.2, April 2004 Version 2, March 2006. The Calibration section received major updates. Other sections received minor modifications.
March 1, 2006 -- pH, Section 6.4 Version 1.2, 7/2003 Version 1.3, 1/2006. The new version includes minor updates and reformatting of subsections.
9/30/05 -- Section 6.7 Revise the Excel spreadsheet of turbidity parameter and method codes. Changes are ongoing and can be accessed from water.usgs.gov/owq/FieldManual/Chapter6/ 6.7_contents.html.
9/30/05 -- Change from 5/16/05 entry (below) Update 6.0, 6.6, 6.7, as needed. Updated versions of sections 6.0 and 6.3 have been posted.
5/16/05 --
Sections 6.1, 6.2, 6.3, 6.4, 6.5
Updates are being made to listed sections, and references will be included with each section rather than being grouped in the back of the chapter. 6.1 Temperature (updates needed)
6.2 Dissolved Oxygen (rewrite in completion) (8/2005)
6.3 Specific Electrical Conductance (updates needed)
6.4 pH (updates needed)
6.5 Redox (updates needed)
2/2/05 -- Section 6.7 - "Tubidity"
(version 2.0, 8/2004)
Selected references (see "Change To" column) to NTU should be updated to include NTRU. p. 36, section 1b, 3rd line: Insert "or NTRU" after "in NTU"

p. 38, section 1, first bullet, 2nd line down: Insert "or NTRU" after "and NTU"

p. 41, section 6e, first bullet: Insert "or NTRU" after "use NTU".
1/31/05 -- Section 6.7 - "Turbidity."
On Web page water.usgs.gov/owq/ FieldManual/Chapter6/ 6.7_contents.html,
go to the link for "Turbidity parameter codes and methods codes"
(Excel spreadsheet)
For the Orion AQ4500 turbidity meter (Thermo Electron Corporation), the correct reporting unit and NWIS pcode for white-light source are NTRU (63676). Delete NTU 63675 codes. Also, add the AU 63678 and FAU 63683 codes. The changes for the Orion AQ4500 listed below will be entered with the next update of the Excel spreadsheet as follows:
Instrument:     Orion AQ4500     Method
NWIS Pcode     Rep. Unit         Description/                                                             Source
63676                  NTRU             EPA 180
63680                   FNU             ISO-NEPH
63683                  FAU             ISO-ABSB and
                                                    IR%T
63681                   FNRU         IR RATIO
63678                   AU             WHITE   %T
8/11/04 -- Section 6.7, "Turbidity" Add a section or explanation on how to use calibration constants to troubleshoot and quality assure turbidity calibrations. This suggestion is likely to be incorporated into the next update of section 6.7. An example of use of calibration constants for quality assurance of the turbidity determination follows:

The submersible probes manufactured by YSI (models 6026 and 6136) have a desired operating range for their constants (see the YSI 6-series manual); these can be quite valuable in determining the validity of a calibration. For example, a discrepancy was found in some calibrations when going from an old bottle of Formazin to a new one (from the same manufacturer). Technical support at YSI suggested checking the constants, and the resulting data showed significant improvement in the constant when a new bottle of standard was used. Also, data showing deterioration of the constant after instrument calibration indicates that there may be a problem with the instrument sensor or with the particular bottle of standard used. Constants also can be used to determine how carefully field personnel mix standards. For the YSI units, the constants can be easily retrieved using a display unit or they can be downloaded as a printable historic record/file using their Ecowatch software (usually provided free with the purchase of a sonde unit). Assuming that one keeps good notes and careful track of their standards, monitoring the constants could potentially save time and money when trying to clear up confusion or subtle problems that might arise with successive calibrations.
8/28/03-- Section 6.4.1Second paragraph begins: "Measurement of pH can be either electrometric or colorimetric." Delete this sentence.

Chapter 7. Biological Indicators

DATE POSTED/
SECTION/PAGE
COMMENTS/ERRATAACTION
July 11, 2013
Section 7.1
Section 7.1 needs to be checked for updates. Check for broken links, such as http://oh.water.usgs.gov/micro/qcmanual/manual.html on p. 40, 7.1.3.A Replace link with http://oh.water.usgs.gov/micro_qaqc.htm
Feb.5, 2008
Cover, Contents, and Introduction
Updates needed. The front pages of Chapter 7 have been updated to include a new section in the Contents: 7.5, "Cyanobacteria in Lakes and Reservoirs: Toxin and Taste-and-Odor Sampling Guidelines." Additional minor revisions updated the pages.
11/2/2007
Section 7.4,
ver. 1.0 (8/2007)
p. 39
INQUIRY - Please explain the following: "If the water body being sampled is too shallow to collect at half of the Secchi depth, then collect the sample at half the depth of the water column." Can you measure the Secchi depth when it is greater than the depth of the water column? Maybe if Secchi depth is determined at a different, deeper location?" RESPONSE - Yes, one can measure Secchi depth when it is greater than depth of the water column; however, when reporting the data, use a "greater than" (>) remark code (it is better than no measurement at all).
11/2/2007
Section 7.4,
ver. 1.0 (8/2007)
p. 39
INQUIRY - Page 39 states that the depth of the euphotic zone "commonly is approximated by measuring the Secchi depth and collecting the sample at half of the Secchi depth." Shouldn't one DOUBLE the Secchi depth to approximate the euphotic zone? The Secchi depth approximates the penetration of 5 percent of the incident surface light. Since the euphotic zone is defined as the depth to which 1 percent of the surface light penetrates, the euphotic zone would have to be greater than the Secchi depth, not less. RESPONSE - The authors explain that no change to the text is needed.
The purpose for collecting at half the Secchi depth is to sample at the approximate middle of the euphotic zone. The text on p. 39 could be modified as follows to clarify the intended meaning:
1. Determine the euphotic zone using Secchi depth and (or) a light meter and the location to be sampled. (Note: The calculated euphotic depth is comparable to a Secchi-disk depth in lakes.)
2. Collect samples within the euphotic zone. This depth commonly is approximated by measuring the Secchi depth. (The text in italics repeats step 1.) Samples are commonly collected at half of the Secchi depth, which is the approximate middle of the euphotic zone.
-- If the water body being sampled is too shallow to collect at half of the Secchi depth, then collect the sample at half the depth of the water column.
-- These methods may vary depending on study objectives.
Oct. 23, 2007
Section 7.4,
ver. 1.0 (8/2007)
p. 11 and 65
USEPA Method 445 for chlorophyll (CHL) analysis stipulates a holding time of 24.5 days from the time of sample collection for frozen samples. The holding time stipulated in NFM 7.4 is 24 days. Note that the protocol of the USGS National Water Quality Laboratory (NWQL) is that the data for CHL samples that are analyzed after 25 days will be qualified appropriately. The NWQL protocol for CHL samples that are analyzed after 25 days from sampling has been added.
October 2007
Section 7.1,
ver. 2.0 (2/2007) p. 40 and 73
The references to Office of Water Quality (OWQ) Technical Memorandum 2005.02 need updating. OWQ Tech Memo 2007.06 supersedes OWQ Tech Memo 2005.02. Change 2005.02 to 2007.06 twice on page 40 (and the year 2005 to 2007) and revise the reference on p. 73 from OWQ Tech Memo 2005.02 to OWQ Tech Memo 2007.06.
June 2007 Need to add information on chylorphyll sampling. A new section on sampling for algal biomass indicators has been approved. Publication is scheduled for FY 2007.
June 2007 Updates are needed to relevant sections of Chapter 7 to reflect information in Office of Water Quality Technical Memorandum 2005.02 (available from water.usgs.gov/admin/memo/). Updates to Section 7.1, Fecal Indicator Bacteria, have been approved. The section is being prepared for online publication.
8/26/2005
Section 7.1.5, first sentence.
1. mENDO medium for total coliform analysis.
    a. Empty the vial containing 4.8 g of dehydrated mENDO medium into a 250-mL flask and add 100 mL of a 2 percent ethanol solution.
1. mENDO medium for total coliform analysis.
    a. Empty the vial containing 5.1 g of dehydrated mENDO medium into a 250-mL flask. Add 100 mL of an ethanol solution. To prepare the ethanol solution, combine 2 mL of 95% undenatured ethanol with 98 mL of deionized/distilled water and mix well.
8/2005 For changes incorporated from 1999 thorugh July 2005, go to the archive file. Currently no changes are noted for the third edition of chapter 7.

Chapter 8. Bottom-Material Samples

DATE POSTED/
SECTION/PAGE
COMMENTS/ERRATAACTION
8/2005 For changes incorporated from 1999 thorugh July 2005, go to the archive file. Currently no changes are noted for version 1.1 dated 6/2005.

Chapter 9. Safety in Field Activities

Comment: For a comprehensive safety policy on streamgaging, see USGS Water Resources Division (WRD) Memorandum 99.32, SAFETY--WRD Policy for Safety Associated with Discharge Measurements, Sampling, and Related Streamgaging Activities. The memo is available at: http://water.usgs.gov/admin/memo/. Click on "WRD Policy and Safety", scroll down the page and click on "wrdpolicy99.32.html". This memo not only provides policy, but it also is meant to improve safety awareness. Emphasizing safety in the workplace does reduce the chance of serious injury and benefits everyone.

DATE POSTED/
SECTION/PAGE
COMMENTS/ERRATA ACTION
8/2006 -- p. 45
Section 9.9.1
Danger from mosquitoes is missing. Add information on mosquitoes to section 9.9.1, including the following recommendation on use of insect repellent to avoid contaminating the sample with DEET: Instead of a DEET-containing repellent, use (a) oil of lemon eucalyptus, or (b) picaridin (a chemical). Reference: http://www.cdc.gov/od/oc/Media/pressrel/r050428.htm
10/10/00 -- p. 11
Section 9.1.1, first paragraph
Reference for A Guide to Safe Field Operations is U.S. Geological Survey, 1995 Change reference to read: A Guide to Safe Field Operations (Yobbi and others, 1996)

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