Citation:

HINNERS, T. A. PRESENTED MAY 10, 2005, MERCURY MEASUREMENTS FOR SOLIDS MADE RAPIDLY, SIMPLY, AND INEXPENSIVELY. Presented at Laboratory Technical Information Group (LTIG) Conference, North Chelmsford, MA, May 10 - 11, 2005.

Impact/Purpose:

Provide state-of-the-science sampling, analysis, separation, and detection methods to allow rapid, accurate field and laboratory analyses of contaminated soils, sediments, biota, and groundwater to support Superfund clean-up decisions. Apply state-of-the-science methods in chemical analysis and data interpretation (e.g., mass spectral interpretation) to actual problems of OSWER, the Regions, and the States, in cooperation with the Las Vegas Technical Support Center as well as by direct contacts with Regional and State employees. Provide technical advice and guidance to OSWER using the environmental chemistry expertise (e.g., mass spectrometry, analytical methods development, clean-up methodology, inorganics, organometallics, volatile organics, non-volatile organics, semi-volatile organics, separation technologies, etc.) found within the branch.

Technical research support for various projects initiated either by Regions/Program Offices or ECB scientists. While these efforts will support the Regions and Program Offices, they cannot be predicted or planned in advance, and may serve multiple duty (e.g., solve real-world problems, serve to ground-truth analytical approaches that ECB is developing, transfer new technology). Many of the activities in this task support requests involving enforcement decisions and therefore are categorized as "environmental forensics".

Description:

While traditional methods for determining mercury in solid samples involve the use of aggressive chemicals to dissolve the matrix and the use of other chemicals to properly reduce the mercury to the volatile elemental form, pyrolysis-based analyzers can be used by directly weighing the solid in a sampling boat and initiating the instrumental analysis for total mercury. Although not well suited for trace-level analyses of liquids because of the limited capacity (0.5 mL) of the sampling boat, such pyrolysis-based mercury analyzers (EPA Method 7473) have the following advantages:

A. Throughput: a measurement every 10-15 minutes (including the weighing and logging time

B. Learning Curve: operation simple enough for those with no prior analytical skill

C. Low Cost: capital cost about $35K

D. Green: generation of waste virtually eliminated

E. Sample Size: 1.00 mg to 500 mg, or 0.5 mL, (but use less if absorbance starts before 5s)

F. Detection Limit: 0.01 nanogram Hg

G. Applications:

- non-lethal monitoring of fish (e.g., tissue biopsy)

- longitudinal analysis of hair (to locate peak-exposure periods)

- exposure assessments for other tissues (e.g., feathers, fur, toenails, botanicals)

- near real-time monitoring of contaminated-soil and sediment during remediations

- coal-fired power plant emissions (from difference between coal Hg and solid waste Hg)

- speciation for mercury in tissues (via suitable extracts of the methyl mercury)

Record Details: