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DETERMINATION OF TOTAL MERCURY IN FISH TISSUES USING PYROLYSIS ATOMIC ABSORPTION SPECTROMETRY WITH GOLD AMALGAMATION
Cizdziel, J V., T A. Hinners, AND E M. Heithmar. DETERMINATION OF TOTAL MERCURY IN FISH TISSUES USING PYROLYSIS ATOMIC ABSORPTION SPECTROMETRY WITH GOLD AMALGAMATION. WATER, AIR AND SOIL POLLUTION:FOCUS 135(1-4):355-370, (2002).
The overall goals of the task are to apply NERL's core capability in advanced chemical science and technology for maximum benefit in estimating exposures of ecosystems and humans to chemical stressors and to identify emerging pollution concerns, in particular long-range airborne transport of contaminants. This task comprises several subtasks, each with individual objectives:
Subtask 1: screen exposures of National Park PRIMENet ecosystems to chemical stressors, identifying indications of exposure requiring further evaluation, and use these samples evaluate new analytical methods as replacements for standard methods in future assessments of ecosystem contaminant exposures.
Subtask 2: evaluate a new mercury analytical approach with superior performance on complex solid matrices such as biological tissues, and apply the approach to estimating exposure of ecosystems and humans to mercury.
Subtask 3: determine distribution patterns of chemical contaminants in the southern Sierra Nevada Range of California, investigate topographic and weather factors that may influence the distributions, and determine if a correlation exists between contaminant distributions and extirpation patterns of the mountain yellow-legged frog.
Subtask 4: provide analytical methods to measure a number of inorganic and organic arsenic species in a variety of environmental matrices, elucidate the environmental transformations undergone by organoarsenic animal-feed additives, and determine if the potential exists for substantially increased exposure of humans and aquatic organisms to arsenic.
A simple and rapid procedure for measuring total mercury in fish tissues is evaluated and
compared with conventional techniques. Using an automated instrument incorporating combustion, preconcentration by amalgamation with gold, and atomic absorption spectrometry (AAS), milligram quantities of wet fish tissue were analyzed directly for mercury (i.e., without acid digestion). Seven tissue types (skeletal muscle, liver, blood, gonad, brain, 01, and heart) from five species offish were analyzed. Because of the small quantities of tissue needed for analysis, we document the homogeneity of mercury within the tissues and determine a preferred sampling technique and location for skeletal muscle. The precision was found to be generaHy<10%(rsd),and the accuracy was determined by using certified reference materials (dogfish muscle, dogfish liver, and oyster tissue). Comparisons to conventional cold-vapor AAS (CV-AAS) and isotope dilution inductively coupled plasma mass spectrometry found that the methods give statistically equivalent (p > 0.05) results. Because the combustion-AAS method is faster than conventional CV-AAS and produces no waste reagents, it should be particularly useful for laboratories that analyze large numbers of fish for mercury. The method detection limit for fish-muscle homogenate was estimated at 0.9 ng/g.
Record Details:Record Type: DOCUMENT (JOURNAL/NON-PEER REVIEWED JOURNAL)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL EXPOSURE RESEARCH LABORATORY
ENVIRONMENTAL SCIENCES DIVISION
ENVIRONMENTAL CHEMISTRY BRANCH