Water Quality--Preservation and Shipment of Water Samples for the Determination of Mercury. In Reply Refer To: September 28, 1984 WGS-Mail Stop 412 QUALITY OF WATER BRANCH TECHNICAL MEMORANDUM 84.18 Subject: Water Quality--Preservation and Shipment of Water Samples for the Determination of Mercury. Effective October 1, 1984, all water samples for the determination of mercury must be contained in 250 mL acid-rinsed glass bottles with polyseal-lined caps and be preserved by the addition of 1 ampoule of nitric acid/potassium dichromate solution. To accomodate the volume of the preservative, the sample volume should not exceed about 200 mL. The preserved sample in its glass bottle should be placed in the poly-foam sleeve provided with each container, the sleeve should be taped closed with nylon strap tape, and the sample placed in double, sealed, polyethylene bags. The bagged sample should be packed and shipped in a water-tight cooler. Samples for mercury determination do not require chilling, but they may be shipped in the same cooler with chilled samples. Standard sample volumes of 200 mL will have a preservative concentration equivalent to 5 percent nitric acid and 0.05 percent potassium dichromate. Samples will have a distinct yellow color and should be designated either FAM or RAM corresponding to filtered or whole-water samples. In his memorandum of September 10, 1984, to Regional Hydrologists, Regional Research Hydrologists, District Chiefs, and Project Offices, the Analytical Services Coordinator announced availability of ampouled nitric acid/potassium dichromate solution and acid-rinsed glass bottles for preserving and containing water samples for the determination of mercury. Bottles and ampoules will be made available in units of 25, free of charge, upon request to the Central Laboratories. Due to limited supply, Districts are urged to limit their requests to reasonable projected needs for not more than 6 months in advance. The logical basis for using an oxidizing agent in conjunction with a strong acid to preserve water samples for the determination of mercury was discussed in the Briefing Paper, "Mercury: Sampling Constraints and Health Considerations," transmitted by Quality of Water Branch Technical Memorandum 84.04, November 30, 1983. If there are further questions concerning preservation and shipment of water samples for mercury determination, please contact Herman Feltz at FTS 928-6834. David A. Rickert WRD Distribution: A, B, FO, PO This memorandum supplements Quality of Water Branch Technical Memorandum 84.16.