Availability of Universal Blank Water for Inorganic and Organic Analyses

In Reply Refer To:
Mail Stop 412                                             April 18, 2002

Office of Water Quality Technical Memorandum 2002.14

Subject: Availability of Universal Blank Water for Inorganic and Organic

The purpose of this memo is to announce that the volatile organic compound
(VOC)/pesticide-grade blank water available from the USGS National Water
Quality Laboratory (NWQL) has been tested and shown to be suitable for use
as inorganic-grade blank water.  Therefore, this blank water, in bottle or
case (One-Stop Shopping item nos. N1580 and N1570), can be used for
equipment and field blanks when collecting samples for organic constituents
(VOCs, pesticides, and/or organic carbon) and inorganic constituents
(nutrients, major ions, and/or trace elements).  This will allow
simultaneous collection of equipment and field blanks for both organic and
inorganic constituents.  Pesticide-grade blank water, in bottle or case
(One-Stop Shopping item nos. N1590 and N1600), is also available from the
NWQL and can be used for simultaneous collection of equipment and field
blanks for both organic (pesticides and/or organic carbon) and inorganic
(major ions and/or trace elements) constituents in situations where VOC
and/or nutrients samples are not being collected.  Inorganic-grade blank
water (One-Stop Shopping item no. Q378FLD) will continue to be available
from the Ocala Water Quality and Research Lab (OWQRL) for projects that are
collecting samples for inorganic analyses only.

BACKGROUND:  At the request of field personnel, and under a NAWQA-NWQL
funded initiative, pesticide-grade blank water that NWQL purchased from EM
Science, and then purged in-house with nitrogen gas to remove VOCs, was
analyzed for nutrients, major ions, and trace elements at several time
intervals.  Initial analyses were run at NWQL immediately after purging,
and again at intervals of 2 weeks, 1 month, and 3 months.  A bottle of a
different lot of EM Science water that had been held in storage at the 
for one year was also tested.  As a field test, the blank water was shipped
to the Maryland District office where samples were prepared for nutrients
(FCC bottle), major ions (FA, FU, and RU bottles), and trace elements (FA
bottle).  Sets of bottles were then reshipped to three other District
offices, which in turn sent them to NWQL as blind blank samples.  NWQL
staff analyzed the blind samples using routine analytical methods: Schedule
2752 (nutrients), Schedule 2750 (major ions), and Schedule 2710 (trace
elements).  In order to ensure suitability for all NWQL customers, NWQL
staff also analyzed these blind samples using the low-level nutrients
method (Schedule 1093).  Details of the experiment are provided in the
attached report (Attachment1).

Tom Maloney and Mary Cast (NWQL Quality Assurance Section) and Michael
Koterba (Maryland District; NAWQA technical support) reviewed the resulting
data.  The data showed that the water is suitable for blanks for inorganic
constituents at the long-term method detection levels (LT-MDL) and the
method reporting levels (MDL) for the analytical methods that were used

The "Universal" blank water can be purchased from NWQL through the One-Stop
Shopping system (item nos. 1570, 1580, 1590, and 1600).  The costs for the
current lot are: N1570 (VOC/Pesticide, nitrogen-purged, case) - $127.00;
N1580 (VOC/Pesticide, nitrogen-purged, bottle) - $42.75; N1590 (Pesticide,
bottle) - $30.25; and N1600 (Pesticide, case) - $102.00.  Pricing for new
lots will be adjusted as necessary to reflect changes in quality-assurance
testing and/or in initial purchase price from the vendor.  The NWQL is
arranging for the purchase of larger lots and anticipates that future costs
will be reduced.  Shelf life is 2 weeks after the purge date for VOCs (no
open bottles of this water are to be stored for use for either inorganic or
organic blanks) or 1 year after the NWQL certificate date (NOT the purchase
date) if the water is not being used for VOCs.  Blank water must be stored
in a location where there is no exposure to vehicle exhaust, cleaning
fluids, or other solvents.

Using this water, blanks can be collected simultaneously for organic and
inorganic analyses.  This change in procedure will necessitate changes in
sections 3.4 and 4.3.1.B of the 'National Field Manual for the Collection
of Water-Quality Data' (NFM) (TWRI Book 9).  Prior to incorporating these
changes into the published chapters, changes will be made in the "Master
Errata" for the NFM, which is located at:

                         Stephen K. Sorenson /s/
                         Acting Chief, Office of Water Quality

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

Distribution:  All WRD Employees

Attachments (2)

(See attached file: blankwater.memo.doc)(See attached file:
waterblank.attach1.doc)(See attached file: blank water-attach2.xls)

Stephen K. Sorenson
Acting Chief, Office of Water Quality
US Geological Survey
412 National Center
Reston, VA  20192