FIELD TECHNIQUES--Sample Preservation and Ampoule Disposal

In Reply Refer To:                            October 3, 1989
WGS-Mail Stop 412


SUBJECT:  FIELD TECHNIQUES--Sample Preservation and Ampoule


A number of years ago, the Montana District noted that split 
samples analyzed in the Denver Central Laboratory indicated 
sporadic positive values of mercury (Hg) compared to less-
than-detection values reported by a laboratory in Canada.  
Several months ago, the Illinois District identified a 
possible Hg contamination problem in the analyses of water.  
Samples analyzed by the Illinois Environmental Protection 
Agency (IEPA) indicated that Hg was present in samples 
collected by the U.S. Geological Survey (USGS), but that 
no Hg was found in samples collected by IEPA personnel.  
Furthermore, sites previously sampled by the IEPA and 
presently sampled by the USGS for the National Water-Quality 
Assessment (NAWQA) Program show sporadic measurable 
concentrations of Hg in the NAWQA results.  

Recently, limited field-blank studies conducted by the Office 
of Water Quality (OWQ) resulted in 2 of 10 blanks testing 
positive for Hg.  Additional studies by LeRoy Schroeder, 
Branch of Quality Assurance (BQA), indicated no positive 
results for Hg in field blanks submitted with atmospheric 
deposition samples.  However, Art Horowitz (Georgia District) 
recently investigated the effects of nitrocellulose filters 
and found trace amounts of Hg in filtered blanks.  

At present, the Division appears to have a sporadic Hg con-
tamination problem in water samples, but we have not identified 
the source(s).  During FY 1990, the OWQ, the BQA, and the 
National Water-Quality Laboratory (NWQL) will continue to 
evaluate the problem by conducting collaborative studies with 
selected District offices and with projects of the National 
Research Program.


Until the source(s) of Hg contamination are determined, we 
request that all field personnel pay special attention to 
(1) the order in which preservations are added to sample 
bottles, and (2) the manner in which empty ampoules are 
discarded.  The following procedures will help reduce the 
chances of contaminating trace metal samples with chromium 
and mercury samples with mercury:

1.  Wearing surgical rubber gloves, rinse the gloved hands 
    with deionized or distilled water to remove powder or 
    other residues.  Then, thoroughly dry gloved hands with 
    good quality absorbent paper towels before handling the 
    first preservative.  Rinse and dry gloved hands before 
    adding each successive preservative.

2.  Prepare samples in the following order:

    A.  Fill a bottle with sample for trace metals analysis.      
        Add contents of the nitric acid ampoule to the 
        sample.  Discard used ampoule and tip (see 3A below).
        Cap the sample bottle and set aside.
    B.  Fill a bottle with sample for mercury analysis.   
        Add contents of the nitric acid/potassium dichromate 
        ampoule to the sample.  Discard used ampoule and tip.
        Cap the sample bottle and set aside.
    C.  Fill bottle(s) for nutrient analysis.  Add contents 
        of the mercuric chloride ampoule to the sample(s).
        Discard used ampoule(s) and tip(s).  Cap the sample
        bottle(s) and set aside.
    D.  Fill bottles for stable isotope analysis.  Add a 
        mercuric chloride tablet to each sample.  Cap the 
        bottles and set aside.
    E.  Wash gloved hands and discard the gloves in regular 

3.  A.  Dispose of each empty ampoule and tip immediately
        following use and before filling a bottle for the
        the next sample.  The two parts of the ampoules
        should be placed in either a wide-mouth glass 
        screw-cap Mason jar or a steel disposal can 
        (available from  laboratory supply houses).  The
        disposal container should be filled to 1/4 volume
        with tap water to minimize shock breakage to the 
        used ampoules.  Cap each disposal container before 
        departing the work site to prevent potential escape 
        of Hg vapor.  Use a different container at each site.
    B.  Transport the disposal container to a Field Service
        Unit or Project Laboratory.  
    C.  Place the container in a sink and open carefully 
        with gloved hands while wearing safety glasses.
    D.  Flush container with copious volumes of tap water.
    E.  Drain container, refill, and flush a second time.
    F.  Drain container and place the ampoules and tips in a 
        polyethylene bag.
    G.  Close the bag and discard in regular trash.
    H.  Clean container thoroughly before reuse.

We will update this memorandum as progress is made toward 
identifying and removing the source(s) of Hg contamination.

                               David A. Rickert
                               Chief, Office of Water Quality

This memorandum does not supersede any existing memorandum.

Key words:  Mercury, sample contamination, ampoule disposal

Distribution:  A, B, FO, SO, PO