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JUDGING PUBLIC RISK - NOT ALL ARSENICS ARE CREATED EQUAL
Citation:
MOMPLAISIR, G., C. G. ROSAL, AND ED HEITHMAR. JUDGING PUBLIC RISK - NOT ALL ARSENICS ARE CREATED EQUAL. Presented at US EPA ESD Open House, Las Vegas, NV, December 09, 2004.
Impact/Purpose:
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.
Description:
Many trace elements occur in the environment in several chemical forms, called species. Each species has unique physical-chemical properties that affect how it moves in the environment, as well as how available and toxic it is to humans and other animals. Hyphenated techniques, the coupling of highly efficient separation methods with selective and sensitive elemental detectors, are employed by chemists in ESD's Environmental Chemistry Branch to selectively measure individual trace-element
species. This analytical chemistry approach is called speciation. Speciation of toxic trace-elements gives environmental decision makers a more complete picture of the potential for exposure than total (non-speciated) trace-element data provides. This poster describes speciation as it is performed at ESD, and demonstrates its application in a project to determine the environmental transformation and fate of arsenic animal-feed additives.