Changes in Field Treatment Protocols and Bottle Types for Whole-Water Samples Collected for Total Ammonium plus Organic Nitrogen and Total Phosphorus Determinations

Date: Wed, 25 Nov 1998 11:34:53 -0500
From: Nana Snow 
Reply-To: "Nana L Snow, Secretary (OA), Reston, VA "
To: "E  - All WRD Employees"
CC: "  WRD Archive File,  "
Subject: OWQ 99.004--Changes in Field Treatment Protocols and Bottle Types for


In Reply Refer To:
Mail Stop 412                                     November 25, 1998

OFFICE OF WATER QUALITY TECHNICAL MEMORANDUM NO. 99.04

Subject:    Changes in Field Treatment Protocols and Bottle Types for
            Whole-Water Samples Collected for Total Ammonium plus
            Organic Nitrogen and Total Phosphorus Determinations

This technical memorandum pertains to changes, effective January 1,
1999, in field-treatment protocols and bottle types for whole-water
samples collected for determining ammonium (see definitions) plus
organic nitrogen (Kjeldahl nitrogen) and phosphorus.  Specifically, it
announces that,

1.      Whole-water samples collected for these analyses will be 
preserved with sulfuric acid at collection sites, and

2.      Translucent ("plain"), polyethylene bottles will be used to
collect, ship, and store these samples rather than the brown ones
formerly specified.

As a consequence of these changes, RCA and RCC sample designators (see
Table 1) will be discontinued and replaced by a new WCA (Whole-water,
Chilled, Acidified) sample designator (see table 2) on January 1, 1999.
Table 3 shows bottle-type changes for affected analyses.  Note that
National Water Quality Laboratory (NWQL) codes and NWIS (National Water
Information System) parameter and method codes for affected analyses
remain unchanged.

Between January 1, 1999 and February 28, 1999, RCC samples inadvertently
sent to the NWQL will be preserved with sulfuric acid and designated as
WCA samples prior to analyses at no charge to the customer.  After this
grace period, all RCC bottles received at the NWQL will be returned at
submitters' expense or discarded.

Table 1.  Excerpt from the current NWQL catalog showing sample
designations, container sizes, container types, and treatment protocols
that will be discontinued December 31, 1998

[mL, milliliter; oz, ounce; deg C, degree Celsius; RCA, raw chilled
acidified; RCC, raw chilled]
_______________________________________________________________________ 
Sample          Container   Container        Treatment and preservation
designation     size        type
_______________________________________________________________________

RCA             125 mL      Brown           Use unfiltered sample to
                (4 oz)      polyethylene    rinse bottles, acidify with
                            bottle          H2S04, chill and maintain at
                                            4 deg C; ship immediately.

RCC             125 mL      Brown           Use unfiltered sample to 
                (4 oz)      polyethylene    rinse bottles, chill, and 
                            bottle          maintain at 4 deg C; ship 
                                            immediately.
_______________________________________________________________________

Table 2. Entry to the NWQL catalog, effective January 1, 1999, showing
new sample designation, container size, container type, and treatment
protocol for whole-water nutrient samples

[WCA, whole-water, chilled, acidified; mL, milliliter; oz, ounce; deg 
C, degree Celsius]
______________________________________________________________________

Sample          Container     Container     Treatment and preservation
designation     size          type
_______________________________________________________________________

WCA             125 mL        Plain          Use unfiltered sample to 
                (4 oz)        (translucent)  bottles, acidify with 1 mL 
                              polyethylene   of 4.5 normal (N) H2S04, 
                              bottle         chill and maintain at 4 deg 
                                             C; ship immediately.
____________________________________________________________________

Table 3.  Discontinued and replacement bottle types for 
nutrient determinations in whole-water nutrient samples.

[ASF, automated-segmented flow; WWR, whole-water recoverable]
_______________________________________________________________________

Lab     NWIS            Procedure name           Required bottle type
code    Parameter                                Before        After
        (method)                                 1/1/99        12/31/98
        codes
_______________________________________________________________________

1982    00665 (F)     Colorimetry, ASF, acid        RCC          WCA
                      persulfate digestion, low-
                      level phosphorus, as P, WWR

1984    00665 (D)     Colorimetry, ASF, micro-      RCC          WCA
                      Kjeldahl digestion,
                      phosphorus, as P, WWR

1986    00625 (D)     Colorimetry, ASF, micro-      RCC          WCA
                      Kjeldahl digestion, ammonia
                      + organic nitrogen, as N, WWR
 
1993    00665 (E)     Colorimetry, ASF, micro-      RCA          WCA
                      Kjeldahl digestion, phosphorus,
                      as P, WWR, acidified

1995    00625 (E)     Colorimetry, ASF, micro-       RCA         WCA
                      Kjeldahl digestion, ammonia +
                      organic nitrogen, as N, WWR,
                      acidified
_______________________________________________________________________

Process WCA bottles at collection sites as follows:

1.      Field rinse the translucent, 125-mL polyethylene bottles with 
three 10- to 15-mL volumes of well-mixed, whole water dispensed from 
churn or cone splitters.  Then fill bottles to the level of their 
shoulders (approximately 120 mL).
2.      Add 1 mL of sulfuric acid preservative to each WCA bottle and 
secure the cap.
3.      Immediately shake or swirl the bottle to mix the sulfuric acid 
preservative with the sample.
4.      Pack processed sample bottles in ice and ship them with next-day
priority to the NWQL for analyses.


Required field supplies, available from the USGS Quality of Water
Service Unit (QWSU) in Ocala, Florida, are tabulated below.
_______________________________________________________________________

QWSU            Item Description                             Quantity
Number
_______________________________________________________________________

407FLD          Bottle, Poly., Plain, 4 oz (125 mL)          Case (100)
406FLD          Bottle, Poly., Plain, 4 oz (125 mL)          Case (500)
26FLD           Bottle Cap, Plastic, 28 mm                   Box (900)
417FLD          Bottle Cap, Plastic, 28 mm                   Pack (100)
438FLD          Vial (PP), H2SO4, 4.5 N (1:7), 1 mL,         Box (24)
                Whole Water (WCA) Nutrient Preservative
_______________________________________________________________________

RATIONALE FOR CHANGES

On October 1, 1994, the USGS discontinued the practice of adding 
mercuric chloride to samples collected for nutrient analysis (U.S. 
Geological Survey Office of Water Quality Technical Memorandum No. 
94.16, 1994).  The decision to discontinue this practice was based on 
preliminary analysis data from the USGS nutrient preservation experiment
(Patton and Truitt, 1995).  Additional statistical analysis of these 
data (Patton and Gilroy, in press) suggested that for some whole-water 
samples containing high (1.5 to 5.5 mg of NH4-N/L) initial ammonium 
concentrations, sulfuric acid or mercury (II) preservative was necessary
to ensure stability of the ammonium fraction of Kjeldahl nitrogen during
30-day storage at 4°C.  The cause of this instability is unknown, but 
may be rationalized by the assumption of high biological activity in 
affected samples.  Sulfuric acid preservative was selected in preference
to mercury (II) preservative for stabilizing whole-water nutrient 
samples during storage because of its comparable effectiveness and lower
toxicity.  Patton and Gilroy (in press), upon which these changes are 
based, received Director's approval on June 24, 1998, and is accessible 
in its entirety as an Acrobat PDF document from the NWQL home page 
(http://wwwnwql.cr.usgs.gov/).

The primary reason for the change to a translucent container for WCA 
samples is to enable laboratory analysts to estimate the quantity and 
settling rate of suspended solids in whole-water samples by visual 
inspection prior to analysis.  With this change, the analysts' ability 
to obtain representative subsamples for whole-water digest preparation 
will improve.  An added, anticipated benefit of using different bottles 
for collection and storage of dissolved and whole-water nutrient samples
is reduced potential for collection-site and laboratory bottle mix-ups.

The new WCA designation was established to emphasize that a specific 
sulfuric acid concentration (1 mL of 4.5 N H2SO4 per 125-mL container) 
is now required.

Because our data have shown that 30-day storage stability of filtered
nutrient species is not improved by sulfuric acid amendment (Patton and
Gilroy, in press), this memo has no direct effect on field treatment
protocols or bottle types for filtered nutrient samples.  However,
acidification of filtered nutrient samples is required by some U.S.
Environmental Protection Agency (USEPA) protocols.  When filtered 
nutrient samples are collected in compliance with USEPA protocols, it is
recommended that the WCA preservative (1 mL of 4.5 N H2SO4 per 125 mL of
sample) be added to FCA (filtered, chilled, acidified) samples.  Use of
this preservative in all acidified nutrient samples will provide the
NWQL with a known and consistent analytical matrix, which in turn should
improve the analytical data quality.

                                DEFINITIONS

Ammonium.  As discussed in Office of Water Quality Technical Memorandum 
93.12, the long-established and prevailing convention of reporting the 
sum of ammonium (NH4+) and solvated ammonia (NH3 {aq}) as "ammonia" is 
misleading and confusing, because ammonium is the overwhelmingly 
predominant species in most unpolluted natural water systems and in 
Kjeldahl nitrogen digests.  In an effort to achieve and promote 
technical correctness, this memo uses ammonium to describe the analyte 
reported as ammonia in the NWQL SPiN database.

Analyte.  As used in this memo, analyte is the substance being
identified and measured in an analytical determination.

                                REFERENCES

Patton, C.J., and Gilroy, E.J., in press, U.S. Geological Survey
nutrient preservation experimentóExperimental design, statistical
analysis, and interpretation of analytical results: U.S. Geological
Survey Water-Resources Investigations Report 98-4118.

Patton, C.J., and Truitt, E.P., 1995, U.S. Geological Survey nutrient 
preservation experimentóNutrient concentration data for surface-, 
ground-, and municipal-supply water samples: U.S. Geological Survey 
Open-File Report 95-141, 140 p.

U.S. Geological Survey, 1994, New preservation techniques nutrient 
samples: Office of Water Quality Technical Memorandum No. 94.16, 
accessed September 30, 1998, at URL 
http://water.usgs.gov/admin/memo/QW/qw94.16.

U.S. Geological Survey, 1998, Reporting level changes for volatile 
organic compounds (Schedules 2020/2021), Inductively Coupled Plasma- 
Atomic Emission Spectrometry (ICP-AES), Ammonia plus Organic Nitrogen 
and Phosphorus (micro-Kjeldahl) in Water Methods at the National Water 
Quality Laboratory:  National Water Quality Laboratory Technical 
Memorandum No. 98.07, accessed September 30, 1998, at URL 
http://nwql.usgs.gov/Public/tech_memos/nwql.98-07.html.


                        Janice R. Ward
                        Acting Chief, Office of Water Quality

Distribution:   All WRD Employees

Contact:  Charles J. Patton, Methods Research and Development 
Program 303/467-8084; email: cjpatton@usgs.gov

This memorandum does not supersede any other Office of Water Quality
Memorandum.

Key Words: Nutrients, Whole-Water Samples, RCA, RCC, WCA, Preservative