FIELD TECHNIQUES--Sample Preservation and Ampoule Disposal In Reply Refer To: October 3, 1989 WGS-Mail Stop 412 OFFICE OF WATER QUALITY TECHNICAL MEMORANDUM NO. 90.01 SUBJECT: FIELD TECHNIQUES--Sample Preservation and Ampoule Disposal BACKGROUND ON MERCURY CONTAMINATION 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. PROCEDURES FOR PRESERVATION OF WATER SAMPLES AND AMPOULE DISPOSAL 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 trash. 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